JP7470488B2 - Fluidized bed apparatus and method for controlling emissions - Google Patents

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of U.S. Patent Application No. 14/808,563, filed July 24, 2015, and claims the benefit of U.S. Provisional Application No. 62/029,044, filed July 25, 2014, and U.S. Provisional Application No. 62/133,791, filed March 16, 2015, the disclosures of which are incorporated herein by reference in their entireties.

This application relates generally to industrial emission control systems and methods, and to apparatus for use in such systems and methods for removing pollutants from gaseous and non-gaseous emissions. An additional field of application relates to marine ship waste and/or ballast water discharges from ships, such as military vessels, cargo ships, tankers, cruise ships, etc.

This section presents background information related to the subject matter disclosed herein that is not necessarily prior art.

Industries in many economic sectors produce one or more types of emissions. These emissions can be divided into two basic groups, one gaseous and the other non-gaseous. Emissions in the gaseous group and non-gaseous groups often contain harmful pollutants. Emissions in the gaseous group may be exhaust gases generated by coal-burning plants or natural gas-burning facilities. Emissions in the non-gaseous group may be liquid, sludge or slurry-like substances. When the levels of harmful pollutants in the emissions reach and/or exceed acceptable limits, the pollutants must be neutralized, captured, collected, removed, disposed of and/or contained in some manner.

Many industries rely on burning fuels as a means to accomplish some aspect of their processes. For example, in the first instance, steel mills burn and/or melt metals during metal forming, extrusion, and other metal casting processes. Processes used within the metal industry include operations that release powders as metal vapors and ionized metals. Harmful contaminants to the environment, plants, animals, and/or humans are released into the air via the metal vapors. To varying degrees, the harmful contaminants in the metal vapors and/or metal vapor compounds must be collected and properly disposed of. In the second instance, the mining industry for precious metals such as gold, silver, and platinum generates metals, metal vapor emissions, and even powders that contain heavy metal contaminants that could be harmful if not captured, collected, and properly disposed of. In the third instance, industries that burn natural gas generate emissions that often contain high levels of pollutants that could be harmful if not captured, collected, and properly disposed of. As a fourth example, energy producers who use coal as a combustible consumable to generate steam in boilers that spin electrical generators generate significant amounts of emissions containing metal vapors and metal compounds that are considered hazardous to the environment, plants, animals, and humans. Metal vapor emissions often contain mercury (Hg), among other hazardous pollutants.

Due to global jet stream patterns, airborne metal vapor emissions can be transported from one country and deposited in another. For example, much of the mercury emissions generated in China and/or India can actually end up in the ocean waters of the United States and/or there between. Similarly, much of the mercury-containing emissions generated in the United States can actually end up in the oceans of Europe and/or there between. Completing the cycle, mercury-containing emissions generated in Europe can actually end up in China and/or India. Thus, mercury and other hazardous pollutants in industrial emissions are a global problem with global implications that require a global effort to solve.

National and international regulations, rules, limitations, fees, oversight, and many, evolving and increasingly stringent laws have been proposed and/or implemented for generators of such emissions. Regulations and/or limitations on harmful emissions vary from country to country throughout the world. However, it is difficult, if not impossible, for one country to enact control measures that encourage (let alone compel) other countries to take steps to reduce harmful emissions generated in that country, even when the emissions may end up in another country, for example.

Japan has been a global leader in reducing mercury production and mercury-containing emissions since the 1970s. Japan has enacted regulations that affect how the larger global community responds to environmental issues specifically related to mercury production. Japan's efforts to promote international mercury legislation are aimed at preventing mercury-related illnesses. In addition to Japan, the United States also has some of the most stringent and restrictive laws and regulations in the world, enforced by the United States Environmental Protection Agency (EPA). Mercury is one of the most harmful pollutants in metal vapor emissions. The EPA has issued new and revised programs, such as the Mercury and Toxic Air Substances Standards, which regulate mercury emissions from various public facilities across the United States, with the goal of reducing the amount of mercury emitted from coal-burning plants by 91% by 2016. These imposed regulations are an ongoing subject of political and legal debate, but the problem remains that harmful pollutants must be dealt with.

EPA enforcement does not extend to producers of toxic emissions within industrialized countries such as India, China, and other foreign countries. Therefore, the United Nations (UN) is trying to pressure its member states to reduce emissions of toxic metal vapors. Representatives of at least 140 member states have agreed to reduce mercury emissions worldwide under a treaty that came into force in 2013. But while some countries have seen global improvements, the expansion of newly industrialized countries appears to be far outpacing advanced reduction efforts.

Although the focus on mercury does not reduce the harmful effects of other pollutants in metal vapor emissions, mercury is potentially the most prevalent and most harmful to animals and humans. Mercury is a natural element present in plants, soils, and animals worldwide. However, human industrial processes have increased mercury accumulations and/or mercury deposits far beyond naturally occurring levels. Globally, the total amount of mercury released by human activities is estimated to be 1,960 metric tons per year. This figure was calculated from data analyzed in 2010. Globally, the largest contributors to this particular type of emission are coal combustion (24%) and gold mining (37%) activities. In the United States, coal combustion accounts for a higher percentage of emissions than gold mining activities.

The main problem with mercury exposure for animals and humans is that mercury is a bioaccumulator. Thus, any amount of mercury ingested by a fish or other animal remains in the animal (i.e., accumulates) and is transferred to humans, or to other animals if the former is ingested by the latter. Furthermore, mercury is not excreted from the host's body. In the food chain, larger predators that are the longest-lived and/or that feed on large numbers of other animals, are most at risk for excessive mercury accumulation. Humans who eat animals (especially fish) that contain mercury are exposed to a wide range of well-known medical problems, including neurological disorders and/or reproductive problems.

There are three main types of mercury emissions: anthropogenic releases, re-releases, and natural releases. Anthropogenic releases are mostly the product of industrial activities. Anthropogenic sources include industrial coal-burning plants, natural gas burning facilities, cement production plants, oil refineries, chlor-alkali and vinyl chloride industries, mining and refining operations. Re-releases occur when mercury is deposited in the soil and redispersed by floods or forest fires. Mercury absorbed and/or deposited in the soil is released back into water by storm runoff and/or flooding. Soil erosion contributes to this problem. Forest fires (whether natural, arson, or fires caused by deliberate deforestation) re-release mercury into the air and/or water sources, where it is deposited elsewhere. Natural releases include volcanoes and geothermal vents. It is estimated that roughly half of all mercury released into the atmosphere comes from natural events such as volcanoes and geothermal vents.

As mentioned above, coal-burning plants release large amounts of mercury and other pollutants into the environment each year. Thus, numerous efforts are currently underway to reduce the amount of harmful pollutants in flue gas emissions generated by coal-burning plants. Many coal-burning plants in the United States are equipped with emissions control systems that capture, seal, and/or regenerate harmful elements such as mercury. In coal-burning plants, coal is burned to boil water, turn the water into steam, and drive generators. Flue gas emissions from coal combustion are often routed through a ducting system and/or a jet dryer system to a fluid gas desulfurization unit, which removes some of the emissions and harmful gases such as sulfur dioxide (SO2) and hydrogen chloride (HCl) from the flue gas. A typical ducting system then routes the flue gas stream to a wet/dry gas scrubber, where more of the sulfur dioxide, hydrogen chloride, and fly ash are removed. The flue gas stream passes through a baghouse, which separates particles from the airflow in the flue gas, similar to a household vacuum cleaner bag. The flue gas passes through a filter-like bag with a porosity that allows the airflow to pass through but not the larger particles moving in the airflow. The surface of the filter bag is agitated and/or washed to collect the trapped particles so that they can be disposed of. Generally, these deposits are themselves hazardous emissions and must be disposed of. The remainder of the flue gas that passes through this type of emission control system is released into the atmosphere through a tall chimney.

The problem with this type of emissions control system is that it is practically ineffective at capturing and/or collecting heavy metals such as mercury contained in metal vapors and vapor-like metal compounds. Because coal-fired systems burn coal at relatively high temperatures, approximately 1500 degrees Fahrenheit, the mercury is transformed into nano-sized particles that can pass through even the most effective filter systems. As a result, large amounts of airborne mercury and other harmful pollutants are released into the atmosphere.

Several known systems have been developed to address this challenge to capture and collect mercury from coal combustion systems and/or other emission sources. These fall into one of three categories:

The first category is a group of methods and/or systems that capture mercury by injecting a sorbent into the flue gas stream. Besides precious metals, the most common sorbent material is activated carbon, which is often halogenated with bromine. The sorbent is injected into the flue gas to capture the pollutants in one and/or a combination of the following common emission control systems: electrostatic precipitators, fluidized gas desulfurization systems, scrubber systems, or fabric filter systems. There are several variations of these systems that require the injection of activated carbon at various points in the emission control system after the coal combustion. Some exemplary methods and/or systems of the first category are disclosed in U.S. Patent Nos. 7,578,869, 7,575,629, 7,494,632, 7,306,774, 7,850,764, 7,704,920, 7,141,091, 6,905,534, 6,712,878, 6,695,894, 6,558,454, 6,451,094, 6,136,072, 7,618,603, 7,494,632, 8,747,676, 8,241,398, 8,728,974, 8,728,217, 8,721,777, 8,685,351, and 8,029,600. All of the methods and/or systems described in these exemplary patents produce hazardous and/or unusable waste products that present their own disposal problems. In addition, these methods and/or systems are generally not economically viable and fail to meet emissions regulations imposed by the EPA and/or other agencies.

The main problem with the methods and/or systems of the first category of known solutions is that using activated carbon is expensive and inefficient. The initial cost of the activated carbon is high because only about 10% of the activated carbon interacts with the metal vapor as it passes through the system. Thus, as much as 90% of the expensive activated carbon is wasted in the flue gas, mainly as carbon monoxide (CO) and/or carbon dioxide (CO2). Another problem is that activated carbon often produces fly ash that is not suitable as a raw material for the manufacture of concrete or other industrial products that require a filler. Although there is no significant income from selling the fly ash, in large quantities this by-product of the coal burning plant is actually an additional source of income. By-product amounts of fly ash that are not suitable for use as a filler in concrete must be classified as hazardous waste and therefore incur disposal costs. On the other hand, by-product amounts of fly ash that are suitable for use as a filler in concrete are not classified as hazardous waste and therefore are a saleable product that does not incur disposal costs.

Another problem with the methods and/or systems of the first category of known solutions is that as much as 10% of the mercury in the flue gas is not removed and is released into the environment. This percentage is high compared to the amount of mercury emissions permitted by the EPA and other agencies. Thus, none of the methods and/or systems of the first category of known solutions meet current regulations for the collection and/or capture of mercury in coal-burning plants or similar industrial applications.

Yet another problem with using activated carbon is that its combustion produces carbon monoxide and/or carbon dioxide, which are released into the atmosphere. In the United States alone, it is estimated that 2.8 billion tons of carbon dioxide are produced annually from the use of activated carbon in coal-burning plants. Worldwide, it is estimated that 14.4 billion tons of carbon dioxide are produced annually from the use of activated carbon in coal-burning plants. In addition, activated carbon is not very effective at removing mercury from other forms of non-gaseous emissions, so other methods must be used.

The second category is a set of methods and/or systems that pretreat coal fuels prior to combustion to reduce mercury levels therein. Some exemplary methods and/or systems in this second category are described in U.S. Patent Nos. 7,540,384, 7,275,644, 8,651,282, 8,523,963, 8,579,999, 8,062,410, and 7,987,613. All of the methods and/or systems described in these exemplary patents generate large amounts of unusable coal, which is also considered a hazardous waste. As a result, the methods and/or systems in this second category of known solutions are ineffective and expensive to implement. Furthermore, coal pretreatment often requires large amounts of capital and physical space, making it impractical to modify many existing emission control systems with the necessary equipment.

The third category is a group of methods and/or systems that inject a catalyst into the emission control equipment upstream of the activated carbon injection system. The catalyst in these methods and/or systems ionize the mercury, facilitating its collection and removal from the flue gas. However, such methods and/or systems have low efficiency and high operating costs, making the methods and/or systems in this third category of known solutions not cost-effective. Examples of this third category are described in U.S. Patent Nos. 8,480,791, 8,241,398, 7,753,992, and 7,731,781. In addition to these examples, U.S. Patent No. 7,214,254 discloses a method and apparatus for regenerating expensive sorbent materials using a microwave oven and a fluidized bed reactor. The method selectively vaporizes mercury from the sorbent, at which point the mercury can be captured or concentrated in a special filter for collection. Due to the use of a microwave oven, this method is not practical for large-scale commercial applications and is therefore only useful for regenerating expensive sorbents. Another example is shown in U.S. Patent Application No. 2006/0120935, which discloses a method of using one of several substrate materials to remove mercury from flue gases by imparting an affinity to the mercury as the flue gas passes through an emissions control facility. This method is also not practical for large-scale commercial use.

Current emission control systems and methods therefore generally operate by transferring harmful pollutants from gaseous to non-gaseous emissions, which creates additional emission management problems.

While many laws and regulations focus on metal vapor emissions, other types of hazardous pollutant-containing discharges should not be overlooked, such as slurry and/or slurry-like discharges, sludge and/or sludge-like discharges, liquid and/or liquid-like discharges, and other types of discharges. All of the types of discharges listed may require treatment to neutralize, capture, collect, remove, dispose of, and/or contain in some appropriate manner the hazardous pollutants contained therein. Historically, the most cost-effective and most widely used hazardous pollutant removal treatment involves the use of activated carbon (in some form) through which the discharge passes. Thus, the demand for activated carbon in the United States is expected to exceed 1 billion pounds per year, growing annually through 2017, and cost the industry more than $1 to $1.50 per pound. This equates to approximately $1 billion per year. Much of the projected increase in activated carbon demand will be driven by the implementation of rules issued by the EPA that will require utilities and manufacturers to update their coal-burning plants to comply with stricter requirements.

In addition to the increasingly stringent gaseous emissions regulations, the EPA is also placing stricter regulations on non-gaseous emissions through the Clean Water Act, which must be fully compliant by 2016. The strengthened composite regulations for all types of emissions cover multiple types of emissions produced by various different industries. Businesses that burn fuel to generate electricity, such as electric utilities, generate primary gaseous emissions that contain harmful pollutants. In accordance with industry standards, these gaseous emissions are exposed to activated carbon to capture a sufficient amount of the harmful pollutants to reduce the contaminants in the gaseous emissions to below acceptable limits. The process of removing harmful pollutants from the gaseous emissions resulting from burning this fuel produces secondary non-gaseous emissions, which are liquid or slurry-like materials that contain the harmful pollutants. The harmful pollutants in the secondary non-gaseous emissions must also be captured and/or properly sealed to prevent the release of the harmful pollutants into the environment. Both the primary gaseous effluents and the secondary non-gaseous effluents require means to adequately capture and/or regenerate and/or contain sufficient harmful pollutants to comply with environmental standards. The costs to industry of known methods capable of removing harmful pollutants from secondary non-gaseous effluents are largely prohibitive, forcing some industries to shut down facilities if the costs cannot be passed on to consumers.

According to some practices, non-gaseous emissions that are considered hazardous because they contain high levels of contaminants are disposed of and stored for long periods of time in ponds, piles, or drying beds. While such practices sequester the hazardous contaminants, they are expensive and consume land without neutralizing the hazardous contaminants themselves, which can result in environmental problems at the storage site. One example of a non-gaseous emission is fly ash, which is a natural product of burning coal. Fly ash is essentially identical in composition to volcanic ash. Fly ash contains trace (i.e., minute) concentrations of many heavy metals and other known hazardous and toxic contaminants (e.g., mercury, beryllium, cadmium, barium, chromium, copper, lead, molybdenum, nickel, radium, selenium, thorium, uranium, vanadium, and zinc). By some estimates, 10% of the coal burned in the United States is made up of unburnable material that becomes ash. Thus, the concentrations of harmful trace elements in coal ash are 10 times higher than the concentrations of these elements in the original coal.

Fly ash is considered a pozzolanic material and has long been used in the manufacture of concrete because, when mixed with calcium carbonate, it forms a cementitious material that, when combined with water and other compounds, clumps together to produce a concrete mix suitable for roads, airport runways, and bridges. Fly ash, produced in coal-burning plants, is flue ash consisting of ultra-fine particles that rise with the combustion exhaust gases. Ash that does not rise is often called bottom ash. In early coal-burning plants, the fly ash was simply released into the atmosphere. In recent years, environmental regulations have required the installation of emission control mechanisms to prevent the release of fly ash into the atmosphere. Many plants use electrostatic precipitators to capture the fly ash before it reaches the chimney and escapes into the atmosphere. The bottom ash is usually mixed with the captured fly ash to form what is known as coal ash. Fly ash usually contains higher levels of harmful pollutants than bottom ash, which means that mixing bottom ash with fly ash produces proportional levels of harmful pollutants that comply with many standards for non-gaseous emissions. However, future standards may redefine fly ash as a hazardous material. If fly ash were to be redefined as a hazardous material, it would no longer be able to be used in the manufacture of cement, asphalt, and other commonly used applications. According to one study, banning fly ash from concrete production would increase costs by more than $5 billion per year in the United States alone. This increased cost would be a direct result of substituting other, more expensive materials for fly ash. In addition, due to its unique physical properties, there are no other known suitable substances that can be directly substituted for fly ash as an additive in cement.

According to reports, over 130 million tons of fly ash are generated annually in the United States at over 450 coal-fired power plants. One report estimates that only 40% of fly ash is reused, which means that 52 million tons/year of fly ash is reused, while 78 million tons/year is stored as is in slurry ponds and piles. Fly ash is typically stored in wet slurry ponds to reduce airborne particles and the transport of contaminants out of bulk storage and into the atmosphere or surrounding environment. In addition to airborne emissions of bulk stored fly ash, containment systems required to contain fly ash for long periods of time can also be damaged and/or fail. In one well-known breach in Tennessee in 2008, the dike of a wet storage fly ash pond collapsed, spilling 5.4 million cubic yards of fly ash. This spillage destroyed several homes and polluted nearby rivers. Cleanup costs have not been determined at the time of filing and could exceed $1.2 billion.

As another example, non-gaseous emissions may be found as a by-product of wastewater generation systems in typical coal-fired facilities. Typical wastewater generation systems produce large volumes of water from the boiler and water cooling processes. These large volumes of wastewater contain relatively low levels of contaminants and are used to dilute other wastewater streams that contain higher levels of contaminants. The contaminated wastewater streams, typically discharged from scrubbers, are diluted with large volumes of wastewater from the boiler and/or cooling water processes and then treated with lime in large continuous mixing tanks to form gypsum, which is then pumped to a settling pond. During this process, certain amounts of mercury and other heavy metals are incorporated into the gypsum, which is stabilized for use in wallboard and cement. This gypsum is generally considered non-leachable and is not considered pollution. However, the water from the settling pond is typically discharged down a drain. Current regulations allow this ongoing discharge, but upcoming regulations propose that certain pollutants and/or certain levels of these pollutants must be considered hazardous pollution.

With regard to removing mercury and heavy metals from non-gaseous industrial wastewater streams, carbonates, phosphates or sulfates are often used to reduce the harmful contaminants to low residual levels. One known method for removing mercury and other harmful contaminants from industrial wastewater streams is chemical precipitation. Another known method uses ion exchange. One of the major problems with chemical precipitation and ion exchange methods is that when the amounts of contaminants are high (e.g., when treating fly ash slurry effluents), these methods are not sufficient to comply with increasingly stringent EPA regulations for non-gaseous effluents.

Another source of polluted non-gaseous emissions is the discharge of waste and ballast water from marine vessels. Commercial ships, such as cargo ships and tankers, have both waste and ballast water. Recreational cruise ships also have wastewater that must be treated in port. Military and escort ships also have significant amounts of wastewater.

Offshore drilling operations also generate significant wastewater. Treating the waste on-site at the offshore drilling facility is significantly cheaper than transporting the waste to land for treatment. Therefore, efficient filtration of marine waste prior to discharge into the sea is necessary to maintain appropriate and acceptable ecological regulations.

There are also various known commercial emission control methods and systems sold under different trade names for treating secondary non-gaseous effluents. A process known as Blue PRO is a reactive filtration process that utilizes co-precipitation and adsorption to remove mercury from secondary non-gaseous effluents. Another process known as MERSORB-LW uses a powdered coal-based sorbent to remove mercury from secondary non-gaseous effluents by co-precipitation and adsorption. Another process known as Chloralkali Electrolysis Wastewater removes mercury from secondary non-gaseous effluents during electrolytic production of chlorine. Another process uses adsorption kinetics and activated carbon derived from manure wastewater to remove mercury from secondary non-gaseous effluents. Another process uses polyethyleneimine modified porous cellulose matrix as an adsorbent to remove mercury from secondary non-gaseous effluents. Another process uses microorganisms during enzymatic reduction to remove mercury from secondary non-gaseous effluents. Yet another treatment method, known by the trade name MerCURxE, uses chemical precipitation reactions to treat contaminated liquid non-gaseous effluents.

This section provides a general summary of the disclosure and is not intended to be a comprehensive disclosure of its entire scope or all of its features.

In one aspect of the present disclosure, an apparatus for removing contaminants from an exhaust is disclosed. The apparatus includes an inverted venturi-shaped housing. The housing includes an inlet section through which the exhaust flows at a predetermined inlet flow rate, an outlet section through which the exhaust flows at a predetermined outlet flow rate, and an expanded diameter section disposed between the inlet section and the outlet section of the housing and configured to capture contaminants in the exhaust. The inlet section, the outlet section, and the expanded diameter section of the housing are disposed to be in fluid communication with one another. In addition, the inlet section of the housing has an inlet cross-sectional area, the outlet section of the housing has an outlet cross-sectional area, and the expanded diameter section of the housing has an expanded diameter cross-sectional area. According to the inverted venturi shape of the housing, the expanded diameter cross-sectional area is larger than the inlet cross-sectional area and the outlet cross-sectional area. Due to the shape of the housing, the exhaust flowing into the expanded diameter section of the housing is decelerated and passes through the expanded diameter section of the housing at a slower speed than the speed passing through the inlet and outlet sections of the housing. Because the flow of the exhaust slows down in the expanded diameter section of the housing, the residence time of the exhaust in the expanded diameter section of the housing is increased. The apparatus also includes a reactant mass disposed within the enlarged diameter portion of the housing. The reactant mass has a reactive outer surface disposed to contact the effluent. Additionally, the reactant mass includes an amalgam-forming metal on the reactive outer surface. The amalgam-forming metal in the reactant mass chemically bonds with at least a portion of the contaminants in the effluent that pass through the enlarged diameter portion of the housing and reach the reactive outer surface of the reactant mass.

In another aspect of the present disclosure, an emissions control method for removing pollutants from a gaseous exhaust is disclosed. The method includes the steps of burning fuel in a furnace to produce a gaseous exhaust containing pollutants, passing the gaseous exhaust through an electrostatic precipitator and removing a first portion of particulate pollutants from the gaseous exhaust using the electrostatic precipitator, passing the gaseous exhaust through a fluidized gas desulfurization unit and removing sulfur dioxide pollutants from the gaseous exhaust using the fluidized gas desulfurization unit, and passing the gaseous exhaust through a fabric filter unit and removing a second portion of particulate pollutants from the gaseous exhaust using the fabric filter unit. The method may include passing the gaseous exhaust through an inverted venturi device and removing heavy metal pollutants from the gaseous exhaust using the inverted venturi device. Passing the gaseous exhaust through an inverted venturi device and removing heavy metal pollutants from the gaseous exhaust using the inverted venturi device includes passing the gaseous exhaust through a reactant mass disposed in the inverted venturi device. The reactant mass includes amalgam-forming metals that chemically combine with the heavy metal contaminants in the gaseous effluent. Thus, as the heavy metal contaminants combine with the amalgam-forming metals in the reactant mass, the heavy metal contaminants are captured in the inverted venturi device. The method further includes sending the gaseous effluent to a chimney that releases the gaseous effluent to the surrounding atmosphere.

In yet another aspect of the present disclosure, an emission control method for removing contaminants from a non-gaseous effluent is disclosed. The method includes settling the contaminant-containing non-gaseous effluent in a settling basin to remove a portion of the contaminants in the non-gaseous effluent, dewatering a first portion of the non-gaseous effluent in the settling basin, using the dewatered by-product in a secondary industrial process, removing a second portion of the non-gaseous effluent from the settling basin, and subjecting the second portion of the non-gaseous effluent to a dry waste treatment process. The method may further include conveying a third portion of the non-gaseous effluent in the settling basin to a treatment vessel containing a sorbent. The sorbent includes amalgam-forming metals that chemically bond with heavy metal contaminants in the third portion of the non-gaseous effluent. Thus, the sorbent captures heavy metal contaminants in the treatment vessel as the heavy metal contaminants chemically bond with the amalgam-forming metals in the sorbent. The method may further include conveying the non-gaseous effluent from the treatment vessel to a drain for discharge.

The apparatus and methods described herein have numerous advantages over known emission control systems and methods. The disclosed apparatus and methods significantly reduce and/or eliminate the need for activated carbon for coal burning emissions. Currently, the initial cost of the amalgam-forming metals and sorbent in the reactant mass disclosed herein is only $1 to $1.5 higher than the pound acquisition cost of activated carbon. However, the amalgam-forming metals can be reactivated and the hazardous contaminants can be collected and reused, so the increased cost is a one-time expense. As a result, the first year cost of using the amalgam-forming metal containing materials disclosed herein, including regeneration and reactivation costs, is estimated to be 1.5 times the annual cost of activated carbon or $1.5 billion nationwide. However, the estimated annual cost after the first year investment only includes the annual regeneration and reactivation costs, which is estimated to be $250 million nationwide. Thus, over a ten-year period, the first year cost to the U.S. industry would be $1.5 billion, with regeneration and revitalization costs of $250 million each for the next nine years, for a total ten-year cost of $3.75 billion. This figure is low compared to the over $10 billion cost of using activated carbon, and represents a significant cost savings of $6.5 billion over ten years.

In addition to significant cost savings, the present apparatus and methods are more efficient at removing hazardous pollutants from gaseous and non-gaseous emissions than known emission control systems and methods. These improvements are significant enough to allow the industry to meet and/or exceed anticipated regulatory requirements that are not economically feasible with current technology. Thus, the present apparatus and methods have the ability to allow the continued use of fly ash even if regulations reclassify it as a hazardous material, thereby preventing significant cost increases for the construction industry, commercial power generation industry, and other industries that generate non-gaseous ash by-products.

The disclosed apparatus and methods also greatly reduce, if not completely eliminate, the reliance on activated carbon to remove harmful pollutants from gaseous emissions. Reducing the use of activated carbon in emissions control systems is estimated to reduce annual carbon dioxide emissions by as much as 2 billion tons in the United States alone.

In another aspect of the present disclosure, an emissions control method for removing contaminants from a gaseous emission is disclosed. The method includes the steps of: introducing a potentially contaminated gaseous emission source into the system, optionally passing the emission through a dedicated pre-filter, passing the emission through an inverted venturi fluidized bed, optionally passing the emission through a dedicated post-filter, and then discharging the emission from the system. Discharging the emission from the system may be for either an appropriate dedicated disposal of the uncontaminated gas stream and/or for environmentally controlled reduction and/or release.

Specifically, the inverted venturi fluidized bed may be sized to have a length to diameter ratio to optimize the limit residence time of the gaseous effluent as it passes through the specialized adsorbent contained within the device. Through trial and error, the optimal length to diameter ratio for a fluidized bed vessel has been determined to be between 2.9:1 and 9.8:1, preferably 4.4:1, for example. Thus, in one exemplary preferred embodiment, for a 4.5 foot diameter, the length would be 19.8 feet, resulting in a length to diameter ratio of 4.4:1.

Another feature of the exemplary inverted venturi fluidized bed apparatus for gaseous effluent is that it has generally curved, convex ends when viewed from either end of the exterior of the vessel. Testing of an exemplary system with a fluidized bed has demonstrated that the gaseous effluent flow returns randomly on its own, minimizing cavitation turbulence and thus maximizing intimate contact and residence time with the adsorbent. The generally curved, convex ends allow relatively smooth return flow at both ends of the fluidized bed and also minimizes cavitation turbulence of the gaseous effluent. Cavitation turbulence through a filter is known to impede and/or interrupt flow. Extended residence time in the fluidized bed is desired to optimally capture and remove contaminants from the gaseous effluent. However, extended residence time is not optimal in the case of cavitation turbulence. Various baffles and other application-specific flow-restricting obstacles can be incorporated into the fluidized bed housing.

In yet another aspect of the present disclosure, an emission control method for removing contaminants from a non-gaseous emission is disclosed. The method includes the steps of: introducing a potentially contaminated non-gaseous emission source into the system, optionally passing the emission through a dedicated pre-filter, passing the emission through an inverted venturi fluidized bed, optionally passing the emission through a dedicated post-filter, and then discharging the emission from the system. Discharging the emission from the system may be for either an appropriate dedicated disposal of the uncontaminated non-gaseous stream and/or for environmentally controlled reduction and/or release.

Specifically, the inverted venturi fluidized bed may be sized to have a length to diameter ratio that optimizes the limit residence time of the non-gaseous effluent as it passes through the specialized adsorbent contained within the device. Through trial and error, an optimal length to diameter ratio for a fluidized bed vessel has been determined to be between 2.9:1 and 9.8:1, with a preferred length to diameter ratio of, for example, 4.4:1. Thus, in one exemplary preferred embodiment, for a 4.5 foot diameter, the length would be 19.8 feet, resulting in a length to diameter ratio of 4.4:1.

Another feature of the exemplary inverted venturi fluidized bed apparatus for non-gaseous effluent is that it has generally curved, convex ends when viewed from either end of the exterior of the vessel. Testing of the exemplary fluidized bed system has revealed that the flow of non-gaseous effluent returns randomly on its own, minimizing cavitation turbulence and thus maximizing intimate contact and residence time with the adsorbent. The generally curved, convex ends allow relatively smooth return flow at both ends of the inverted venturi fluidized bed, minimizing cavitation turbulence of the non-gaseous effluent. Turbulence associated with cavitation through a filter is known to impede and/or interrupt flow. Extended residence time in the inverted venturi fluidized bed is desired to optimally capture and remove contaminants from the non-gaseous effluent. However, extended residence time is not optimal in the case of turbulent cavitation. Various baffles and other application-specific flow-restricting obstacles can be incorporated into the fluidized bed housing.

In another aspect of the present disclosure, the inverted venturi fluidized bed system for gaseous and/or non-gaseous effluents can be removed from the inverted venturi fluidized bed vessel to capture contaminants from the adsorbent, where the captured contaminants can be appropriately disposed of and/or recycled to appropriate industrial applications. After the adsorbent has been regenerated and/or activated, it can be redeployed to the fluidized bed for further use within the system. A built-in adsorbent inlet can be provided to maintain the amount of adsorbent in the fluidized bed.

According to another aspect of the present disclosure, the inverted venturi shaped fluidized bed can be significantly lighter for personal civilian applications or larger in size for very large commercial applications while maintaining the disclosed length to diameter ratio and generally curved outwardly protruding convex end characteristics. Permanent systems include, but are not limited to, land-based site systems and/or field assembled systems on escort or military vessels and consumer cruise ships. Other possible applications for field assembled systems include industrial coal burning plants, natural gas burning facilities, cement production plants, oil refineries, chlor-alkali industry, vinyl chloride industry, mining operations and smelting operations, among others.

In addition to application-specific permanent systems, the system can also be configured as a portable system. Examples of portable systems include, but are not limited to, truck-mounted systems, barge-mounted systems, trailer-mounted systems, and railcar systems. Applications of portable systems are useful in providing a bypass to a permanent field-assembled system by providing a temporary emissions bypass for repair, inspection, and/or maintenance of the permanent field-assembled system. Portable systems are also useful in providing excess filtration to a permanent field-assembled facility during times when the flow rate of polluted emissions exceeds the capacity of the permanent field-assembled system.

The use of the special sorbents described herein in conjunction with the disclosed apparatus and methods provides numerous advantages. In general, the ability of the disclosed effluent apparatus to capture, contain and/or recycle mercury and other harmful substances is not previously possible using known emission control systems and methods. Another important advantage of the sorbents disclosed herein is that they can be used to treat both gaseous and non-gaseous effluents, thereby overcoming many of the problems of known methods for treating contaminated non-gaseous effluents, such as secondary effluents from primary emission control processes used to treat gaseous effluents. In addition, the sorbents described herein provide the ability to treat gaseous effluents efficiently enough to eliminate the need for secondary treatment of non-gaseous effluents that arise as a by-product of the primary gaseous effluent treatment process. The sorbents disclosed herein are also beneficial in that they are reusable. Through reprocessing methods, harmful contaminants that chemically bind with the amalgam-forming metals in the sorbent can be collected (i.e., removed) from the sorbent, thereby restoring the sorbent's ability to remove contaminants from gaseous and non-gaseous effluents.

Further scope of applicability will become apparent from the description herein. The descriptions and specific examples in this Abstract are for illustrative purposes only and are not intended to limit the scope of the present disclosure.

The drawings described herein are merely intended to illustrate selected embodiments rather than all possible implementations and are not intended to limit the scope of the present disclosure.

Other advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description taken in conjunction with the accompanying drawings, in which:
1 is a schematic diagram illustrating a known configuration of a coal-fired power plant. FIG. 2 is a schematic diagram illustrating a known configuration of an emissions control system used to remove pollutants from the emissions produced by a coal-fired power plant of the type shown in FIG. 1 . 3 is a schematic diagram of the emission control system shown in FIG. 2 and modified by the addition of an exemplary reverse venturi device constructed in accordance with the present disclosure; FIG. 1 is a side cross-sectional view of an exemplary reverse venturi device having a housing with an inlet portion, an expansion portion, and an outlet portion, constructed in accordance with the present disclosure. FIG. 4B is a front cross-sectional view of an inlet portion of the housing of the exemplary reverse venturi device shown in FIG. 4A. FIG. 4B is a front cross-sectional view of the expanded diameter portion of the housing of the exemplary reverse venturi device shown in FIG. FIG. 4B is a front cross-sectional view of an outlet portion of the housing of the exemplary reverse venturi device shown in FIG. 4A. FIG. 2 is a side cross-sectional view of another example reverse venturi device in which a series of interleaved baffles are disposed in an expanded diameter section of a housing to create a serpentine flow path for exhaust material, constructed in accordance with the present disclosure; FIG. 2 is a side cross-sectional view of another exemplary reverse venturi device in which a helical baffle is disposed in an flared portion of a housing to form a helical flow path for exhaust material, constructed in accordance with the present disclosure; FIG. 6B is a front perspective view of the helical baffle of the exemplary reverse venturi device shown in FIG. FIG. 2 is a side cross-sectional view of another example reverse venturi device having a plurality of spaced apart baffles disposed in an expanded diameter portion of a housing, constructed in accordance with the present disclosure; FIG. 7B is a front cross-sectional view of the exemplary reverse venturi device shown in FIG. 7A taken along line AA, with one orifice of the baffle shown. FIG. 2 is a side cross-sectional view of another example reverse venturi device constructed in accordance with the present disclosure, with multiple pieces disposed in an expanded diameter portion of a housing; FIG. 2 is a side cross-sectional view of another exemplary reverse venturi device constructed in accordance with the present disclosure, in which a plurality of entangled threads are disposed in an enlarged diameter portion of a housing to form a filament; FIG. 2 is a side cross-sectional view of another example reverse venturi device constructed in accordance with the present disclosure, the filter element being disposed in an expanded diameter portion of the housing; FIG. 2 is a side cross-sectional view of another example reverse venturi device constructed in accordance with the present disclosure, where the expanded diameter portion of the housing accommodates a plurality of baffles and a plurality of various sized debris disposed between adjacent baffles; FIG. 12 is a front view of an example of a debris size that can be accommodated in the expanded diameter portion of the housing of the example reverse venturi device shown in FIG. FIG. 12 is a front view of another example of a size of debris that can be accommodated in the expanded diameter portion of the housing of the example reverse venturi device shown in FIG. FIG. 12 is a front view of another example of a size of debris that can be accommodated in the expanded diameter portion of the housing of the example reverse venturi device shown in FIG. FIG. 12 is a front view of another example of a size of debris that can be accommodated in the expanded diameter portion of the housing of the example reverse venturi device shown in FIG. FIG. 12 is a front view of one example of an asterisk-shaped piece of loose material that can be used in combination with other pieces to replace the debris shown in the exemplary reverse venturi device shown in FIGS. 8 and 11 . FIG. 12 is a front view of an example of a crystal flake that can be used in combination with other crystal flakes to replace the debris shown in the example reverse venturi device shown in FIGS. 8 and 11 . FIG. 12 is a front view of one example of a wire coil that can be used in combination with other wire coils to replace the debris shown in the example reverse venturi device shown in FIGS. 8 and 11 . FIG. 2 is a side cross-sectional view of another example reverse venturi device having two separated expansion sections connected in series, constructed in accordance with the present disclosure; FIG. 2 is a side cross-sectional view of another exemplary reverse venturi device having two separated expansion sections connected in parallel, constructed in accordance with the present disclosure; FIG. 2 is a side cross-sectional view of another exemplary reverse venturi device constructed in accordance with the present disclosure. 1 is a block flow diagram illustrating a known method for removing pollutants from a gaseous effluent. FIG. 18 is a block diagram illustrating the method of removing contaminants from the gas effluent shown in FIG. 17 modified by adding the step of injecting an adsorbent into the gas effluent at a first introduction point and then passing the gas effluent through an inverse venturi device. FIG. 18 is a block diagram illustrating the method of removing contaminants from the gas effluent shown in FIG. 17 modified by adding the step of injecting an adsorbent into the gas effluent at a second introduction point and then passing the gas effluent through an inverse venturi device. FIG. 1 is a block diagram illustrating a known method for removing contaminants from non-gaseous effluents, which involves settling the non-gaseous effluents in a settling pond. FIG. 20 is a block diagram illustrating the method for removing contaminants from the non-gaseous effluent shown in FIG. 19 modified to include the step of treating a portion of the non-gaseous effluent extracted from the settling pond with a sorbent. 2 is a graph showing the percentage of pollutants removed from an exhaust by known emission control systems and the percentage of pollutants removed from an exhaust by the apparatus and method disclosed herein; 1 is a block flow diagram illustrating an example of a method for using an inverted venturi fluidized bed apparatus to remove contaminants from a gaseous effluent and to scrub reactants that separate the contaminants from the gaseous effluent. 1 is a block flow diagram illustrating an example of a method for using an inverted venturi fluidized bed apparatus to remove contaminants from a non-gaseous effluent and to scrub reactants that separate the contaminants from the non-gaseous effluent. 1 is a flow diagram illustrating an extended non-turbulent effluent flow through an exemplary inverted venturi fluidized bed apparatus and exemplary method steps for washing and recycling the sorbent that separates contaminants from the effluent.

The apparatus and method for removing pollutants from industrial emissions are described with reference to the drawings, in which like reference numerals refer to corresponding elements throughout.

The exemplary embodiments are described more fully with reference to the accompanying drawings. The exemplary embodiments are presented so as to make the disclosure thorough and fully convey the scope of the present disclosure to those skilled in the art. Numerous specific details are described, such as examples of specific components, elements and methods, in order to provide a thorough understanding of the embodiments of the present disclosure. It will be apparent to one skilled in the art that the specific details are not necessary and that the exemplary embodiments can be implemented in many different forms and should not be construed as limiting the present disclosure. In some exemplary embodiments, known methods, known element structures and known techniques are not described in detail.

The terms used herein are for the purpose of describing specific exemplary embodiments only and are not intended to be limiting. As used herein, the singular is intended to include the plural unless expressly stated. The terms "comprises," "comprising," "including," and "having" are inclusive and identify the presence of stated features, integers, steps, operations, elements, and/or components, but do not exclude the presence or addition of one or more features, integers, steps, operations, elements, components, and/or groups. The method steps, processes, and operations described herein should not be construed as necessarily requiring execution in the particular order described or illustrated, unless specifically identified as an order of execution. It is understood that additional or alternative steps may be used.

When an element or layer is described as being "on", "engaged with", "connected to" or "coupled to" another element or layer, the element or layer may be directly on, engaged with, connected to, or coupled to the other element or layer, or there may be an intervening element or layer. On the other hand, when an element is described as being "directly on", "directly engaged with", "directly connected to" or "directly coupled to" another element or layer, there may not be an intervening element or layer. Other language used to describe the relationship of elements (e.g., "between" and "directly between", "adjacent" and "directly adjacent") should be interpreted similarly. As used herein, the term "and/or" includes all combinations of one or more of the associated listed items.

Terms such as first, second, third, etc. are used herein to describe various elements, parts, regions, layers, and/or cut surfaces, but these elements, parts, regions, layers, and/or cut surfaces are not limited by these terms. These terms may be used only to distinguish one element, part, region, layer, and/or cut surface from another region, layer, or cut surface. Terms such as "first," "second," and other numerical terms as used herein do not imply an order or sequence unless clearly indicated by the context. Thus, the first elements, parts, regions, layers, and/or cut surfaces discussed below may be referred to as second elements, parts, regions, layers, and/or cut surfaces without departing from the teachings of the embodiments.

Spatially relative terms such as "inner," "outer," "below," "below," "lower," "above," "on top," and the like may be used herein to facilitate the description of the relationship of one element or feature to another element or feature when illustrated. Spatially relative terms may be intended to encompass different orientations of the device during use or operation in addition to the orientation depicted. For example, if the device in the figures were turned over, an element described as "below" or "below" another element or feature would be placed "above" the other element or feature. Thus, the exemplary term "below" can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein would be interpreted accordingly.

Additionally, the term "conduit" as used herein is intended to cover the description of all pipes typically available for conveying liquid and/or liquid-like effluents and gas and/or gaseous effluents. No preference is intended or implied regarding the actual method of conveying the effluent, regardless of the type of effluent.

With reference to FIG. 1, a schematic diagram of a typical coal-fired power plant 100 is shown. The coal-fired power plant 100 has a fluidized bed reactor 1, which is an industrial facility that burns one or more coal fuels 2 to generate electricity 7. The electricity 7 may then be distributed to the grid via power lines 8. Combustion in the fluidized bed reactor 1 is carried out with air 3, fire 4, and the coal fuel 2. The combustion process is used to heat water to generate steam 5. The steam is then used to turn a generator 6 to generate electricity 7. Gaseous emissions 10 from the combustion process are released into the environment through a chimney 9. If the coal-fired power plant 100 is not provided with any emissions control system (FIG. 1), the emissions 10 include many harmful pollutants such as fly ash, mercury (Hg), metal vapors, sulfur dioxide (SO2), hydrogen chloride (HCl), and other harmful gases.

2, a schematic diagram of an improved coal-fired power plant 200 is shown having a conventional emission control system 202. The emission control system 202 captures and collects a portion of the harmful pollutants in the gaseous exhaust 10. The emission control system 202 conveys the gaseous exhaust 10 from the fluidized bed reactor 1, where the combustion reaction occurs, to a wet/dry scrubber 11, which removes a portion of the sulfur dioxide and fly ash pollutants from the gaseous exhaust 10. Alternatively or in addition to conveying the gaseous exhaust 10 to the wet/dry scrubber 11, the emission control system 202 may convey the gaseous exhaust 10 to a jet dryer 12, where a portion of the sulfur dioxide, harmful gases and other pollutants are captured and collected. The exhaust may be passed through a fabric filter unit 13 (i.e., baghouse), which uses filter bags to remove particles from the gaseous exhaust 10 stream. This system collects and removes many of the pollutants from the gaseous effluent 10 before it is released into the surrounding atmosphere (i.e., the environment) through a chimney 9. The problem with the typical emissions control system 202 shown in FIG. 2 is that nano-sized pollutants such as mercury contained in metal vapor emissions easily pass through the wet/dry scrubber 11, the blow dryer 12, and the fabric filter unit 13 of the emissions control system 202.

3, a schematic diagram of an improved coal-fired power plant 300 is shown having an adsorbent injector 14 and an inverted venturi device 15 in addition to the emission control system 202 shown in FIG. 2. The adsorbent injector 14 operates to add adsorbent to the gaseous effluent 10 and may be located upstream of the inverted venturi device 15. More specifically, in the example shown in FIG. 3, the adsorbent injector is located between the spray dryer 12 and the fiber filter unit 13. In FIG. 3, the inverted venturi device 15 is located between the fiber filter unit 13 and the chimney 9, although it is possible to locate the inverted venturi device 15 in a different location. One of the main advantages of this arrangement is that the inverted venturi device 15 can be installed in an existing facility and only a "Modification to Existing Permit" needs to be applied for, saving both time and money compared to applying for a completely new emission control system. In operation, the gaseous exhaust 10 is directed from the fabric filter unit 13 to the inverse venturi device 15. As will be described in more detail below, the inverse venturi device 15 is equipped with internal structures suitable for collecting and trapping substantial amounts of mercury, heavy metals, nano-sized particles and other contaminants. Thus, the gaseous exhaust 10 exiting the chimney 9 is substantially purified of all harmful contaminants.

4A-4D, the reverse venturi device 15 includes a housing 16 having a reverse venturi shape. It will be appreciated that a venturi is generally described as a conduit that first narrows from a larger cross-section to a smaller cross-section and then expands from the smaller cross-section to a larger cross-section. Thus, the term "reverse venturi" as used herein means the reverse, i.e., a conduit that first expands from a smaller cross-section to a larger cross-section and then narrows from the larger cross-section to the smaller cross-section. Specifically, the housing 16 of the disclosed reverse venturi device 15 extends along a central axis 17 and has an inlet section 18, an expanding section 19, and an outlet section 20. The inlet section 18 of the housing 16 is sized such that the gaseous discharge 10 enters at a predetermined inlet flow rate characterized by an inlet velocity V1 and a pressure P1. The outlet section 20 of the housing 16 is sized such that the gaseous discharge 10 exits at a predetermined outlet flow rate characterized by an outlet velocity V3 and a pressure P3. The enlarged diameter portion 19 is disposed between the inlet portion 18 and the outlet portion 20 of the housing 16, and defines an enlarged diameter chamber 21 therein for capturing contaminants in the gaseous exhaust 10. The enlarged diameter portion 19 of the housing 16 has an inner surface 68 that is generally opposite the central axis 17. The inlet portion 18, the enlarged diameter portion 19, and the outlet portion 20 of the housing 16 are sequentially disposed along the central axis 17 such that the inlet portion 18, the enlarged diameter portion 19, and the outlet portion 20 of the housing 16 are in fluid communication with one another. That is, the inlet portion 18, the enlarged diameter portion 19, and the outlet portion 20 of the housing 16 collectively form a conduit that extends along the central axis 17.

The inlet section 18 of the housing 16 has an inlet cross-sectional area A1 transverse to the central axis 17, and the outlet section 20 of the housing 16 has an outlet cross-sectional area A3 transverse to the central axis 17. The inlet cross-sectional area A1 may be equal to (i.e., the same as) the outlet cross-sectional area A3 such that a given inlet flow rate is equal to (i.e., the same as) a given outlet flow rate. Alternatively, the inlet cross-sectional area A1 and the outlet cross-sectional area A3 may be different (i.e., smaller or larger) such that a given inlet flow rate is different (i.e., smaller or larger) from a given outlet flow rate. As used herein, the term "flow rate" refers to the volumetric flow rate of the discharge.

The enlarged diameter section 19 of the housing 16 crosses the central axis 17 and has an enlarged diameter section cross-sectional area A2 larger than the inlet section cross-sectional area A1 and the outlet section cross-sectional area A3. Thus, the enlarged diameter section 19 is sized such that the flow rate V2 of the gas discharge 10 in the enlarged diameter section 19 of the housing 16 is smaller than the flow rate V1 of the gas discharge 10 in the inlet section 18 of the housing 16 and smaller than the flow rate V3 of the gas discharge 10 in the outlet section 20 of the housing 16. This reduction in flow rate increases the residence time of the gas discharge 10 in the enlarged diameter section 19 of the housing 16. Note that the term "residence time" as used herein means the average time required for molecules in the gas discharge 10 to pass through the enlarged diameter section 19 of the housing 16. In other words, the "residence time" of the enlarged diameter section 19 of the housing 16 is equal to the time required for all the discharge in the enlarged diameter chamber 21 to be renewed. Additionally, the term "cross-sectional area" as used herein refers to the internal cross-sectional area (i.e., the space inside the housing 16) that is the same regardless of changes in the thickness of the housing 16. Thus, the expansion section cross-sectional area A2 reflects the size of the expansion chamber 21 and is defined by the inner surface 68.

Due to the shape of the housing 16, the internal pressure P1 of the gas exhaust 10 passing through the inlet portion 18 of the housing 16 and the internal pressure P3 of the gas exhaust 10 passing through the outlet portion 20 of the housing 16 are greater than the internal pressure P2 of the gas exhaust 10 passing through the enlarged diameter portion 19 of the housing 16. Combined with the fact that the flow velocity V2 of the gas exhaust 10 in the enlarged diameter portion 19 of the housing 16 is less than the flow velocity V1 of the gas exhaust 10 at the inlet portion 18 of the housing 16 and less than the flow velocity V3 of the gas exhaust 10 at the outlet portion 20 of the housing 16, this pressure difference causes the gas exhaust 10 to remain in the enlarged diameter portion 19 of the housing 16. As a result of the pressure and velocity difference described above, and because the gas exhaust 10 naturally expands to occupy the entire volume of the enlarged diameter chamber 21, an expansion force is applied to the gas exhaust 10 in the enlarged diameter portion 19 of the housing 16. This fact, combined with the effects of laminar flow, pneumatic dynamics, and gas behavior physics, results in an increase in residence time that enhances the ability of the reverse venturi device 15 to efficiently capture and thereby remove contaminants from the gas exhaust 10.

The housing 16 may have a variety of different shapes and configurations. As a non-limiting example, the inlet section 18, the flared section 19, and the outlet section 20 of the housing 16 shown in Figures 4A-4D all have circular cross-sectional areas A1, A2, A3. Alternatively, one or more of the cross-sectional areas A1, A2, A3 of the inlet section 18, the flared section 19, and the outlet section 20 of the housing 16 may be non-circular, and various combinations of circular and non-circular cross-sections are possible and are considered within the scope of the present disclosure. In some configurations, the flared section 19 of the housing 16 may have a diverging end 22 and a converging end 23. According to these configurations, the flared section 19 of the housing 16 tapers outward from the inlet section cross-sectional area A1 to the flared section cross-sectional area A2 at the diverging end 22. That is, the cross-section of the flared section 19 of the housing 16 increases at the diverging end 22 as one moves away from the inlet section 18 of the housing 16. In contrast, the diverging section 19 of the housing 16 tapers gradually inwardly at the converging end 23 from the diverging section cross-sectional area A2 to the exit cross-sectional area A3. That is, the cross-section of the diverging section 19 of the housing 16 decreases at the converging end 23 as one moves in a direction toward the exit section 20 of the housing 16. Thus, the gaseous effluent 10 within the diverging section 19 of the housing 16 flows from approximately the diverging end 22 to the converging end 23. In embodiments in which the inlet section 18, the diverging section 19, and the exit section 20 of the housing 16 all have circular cross-sectional areas A1, A2, A3, the diverging and converging ends 22, 23 of the housing 16 may be approximately conical in shape. Notwithstanding the above, the diverging and converging ends 22, 23 of the diverging section 19 of the housing 16 may be otherwise shaped. As a non-limiting example, the diverging and converging ends 22, 23 may be polygonal to facilitate ease of manufacture while not significantly affecting the flow of the gaseous effluent 10 through the housing 16 of the reverse venturi device 15. In another alternative configuration, the expanding section 19 of the housing 16 may have a sausage-like shape with relatively abrupt changes between the inlet section 18 and the diverging end 22 and between the converging end 23 and the outlet section 20. It is presumed that a smooth transition is preferred over an abrupt transition because it favors a more laminar flow behavior of the gaseous effluent 10. However, a slight disturbance to the laminar flow of the gaseous effluent 10 during an abrupt transition is not considered to be an absolute problem, and may even result in better flow in areas where increased residence time is not required.

Continuing with reference to Figures 4A-4D and further to Figures 5-11, a reactant mass 24 is disposed within the enlarged diameter portion 19 of the housing 16. The reactant mass 24 has a reactive outer surface 25 that is disposed in contact with the gaseous effluent 10. Additionally, the reactant mass 24 contains an amalgam-forming metal on its reactive outer surface 25 that chemically bonds with at least a portion of the contaminants in the gaseous effluent 10 that pass through the enlarged diameter portion 19 of the housing 16 and reach the reactive outer surface 25 of the reactant mass 24. In this manner, the contaminants that are bound to the reactive outer surface 25 of the reactant mass 24 remain trapped within the enlarged diameter portion 19 of the housing 16 and are therefore removed from the flow of the gaseous effluent 10 that exits the enlarged diameter portion 19 of the housing 16 and enters the outlet portion 20 of the housing 16. As used herein, the term "amalgam-forming metal" refers to a material selected from a group of metals that are capable of forming a compound with one or more of the contaminants in the gaseous effluent 10. As a non-limiting example, the amalgam-forming metal may be zinc and the contaminant in the gaseous effluent 10 may be mercury, such that an amalgam of zinc and mercury may form when the gaseous effluent 10 contacts the reactive outer surface 25 of the reactant mass 24.

The expansion 19 of the housing 16 must be sized to accommodate the gaseous effluent 10 at a given inlet flow rate while still providing a long enough residence time for the amalgam-forming metals in the reactants 24 to chemically combine with the contaminants in the gaseous effluent 10. Thus, to achieve this balance, the expansion cross-sectional area A2 may range from 3 square feet to 330 square feet to provide a residence time ranging from 1 second to 2.5 seconds. This particular residence time is necessary to provide sufficient time for the contaminants in the gaseous effluent 10 to chemically combine with the amalgam-forming metals in the reactants mass 24. Thus, the range of expansion cross-sectional areas A2 has been calculated to provide this residence time for coal-fired power plants 100 having a power output ranging from 1 megawatt (MW) to 6000 megawatts (MW). As is known in the chemical arts, the amalgam-forming metals may be a variety of different metals. By way of non-limiting example, the amalgam-forming metal may be selected from the group consisting of zinc, iron, and aluminum. The housing 16 is made of a different material than the reactant mass 24. By way of non-limiting example, the housing 16 may be made of steel, plastic, or fiberglass.

The reactant mass 24 may have any of a variety of different configurations. In FIG. 4A, the reactant mass 24 is shown as coating the inner surface 68 of the housing 16. Alternatively, as shown in FIGS. 5-11, the reactant mass 24 may form one or more obstruction elements 26a-26j disposed within the enlarged portion 19 of the housing 16. These obstruction elements 26a-26j themselves form a tortuous flow path 27 for the gaseous effluent 10 passing through the enlarged portion 19 of the housing 16. Thus, the obstruction elements 26a-26j increase the residence time of the gaseous effluent 10 passing through the enlarged portion 19 of the housing 16. In some embodiments described below, the flow of the gaseous effluent 10 through the enlarged portion 19 of the housing 16 is completely disrupted, so that the tortuous flow path 27 formed is completely random, which greatly increases the opportunity for chemical reaction between contaminants in the gaseous effluent 10 and the amalgam-forming metals in the reactant mass 24.

The obstacle elements 26a-26j of each of the structures shown in Figures 5-11 have a large surface area, which increases the reactive outer surface 25 of the reactant mass 24. This is advantageous because a chemical reaction between the amalgam-forming metal in the reactive outer surface 25 of the reactant mass 24 and the contaminants in the gaseous effluent 10 allows the contaminants to be trapped, captured, and/or collected in the enlarged portion 19 of the housing 16, thereby removing the contaminants from the gaseous effluent 10. Thus, the amount of contaminants that can be removed from the gaseous effluent 10 passing through the enlarged chamber 21 by the enlarged portion 19 of the housing 16 is proportional to the size of the reactive outer surface 25 of the reactant mass 24 in the enlarged portion 19 of the housing 16. In addition, the complex surface shape and/or texture of the obstacle elements 26a-26j provide additional surface area that facilitates physical capture of contaminants, whether or not the capture of the contaminants is the result of a chemical reaction between the contaminants and the amalgam-forming metal.

Referring again to FIG. 3, the sorbent added to the effluent by the sorbent injector 14 includes an amalgam-forming metal. The amalgam-forming metal in the sorbent chemically bonds with at least some of the contaminants in the gaseous effluent 10 before the gaseous effluent 10 enters the enlarged diameter portion 19 of the housing 16. Although the sorbent may have many different compositions, the sorbent may be, for example, zinc (Zn) powder or a copper zinc tin sulfide (CZTS) compound. The sorbent enhances the removal of contaminants from the gaseous effluent 10 by the reactant mass 24 because the sorbent chemically bonds with at least some of the contaminants in the gaseous effluent 10 before the gaseous effluent 10 enters the enlarged diameter portion 19 of the housing 16.

5, the obstruction elements 26a-26j are provided as a series of interleaved baffles 26a extending from the inner surface 68 of the enlarged diameter portion 19 of the housing 16. The series of interleaved baffles 26a traverse the central axis 17 and provide a serpentine shape for the meandering flow path 27. The serpentine shape of the meandering flow path 27 increases the residence time of the gaseous exhaust 10 within the enlarged diameter portion 19 of the housing 16, thereby enhancing the capture and removal of contaminants in the gaseous exhaust 10 by the reactant mass 24 forming the series of interleaved baffles 26a. In one example, the series of interleaved baffles 26a is made of zinc. In another example, the series of interleaved baffles 26a is made of a material other than zinc that is coated with zinc. The arrangement of the interleaved baffles 26a need not be equally spaced or symmetrical along the length of the central axis 17. In some applications, it is preferable to have more space between adjacent baffles 26a, while in other applications it is preferable to have less space between adjacent baffles 26a. Also, the series of interleaved baffles 26a may be replaced and/or cleaned as needed if they become saturated during operation of the reverse venturi device 15.

6A-6B, at least one of the obstacle elements 26a-26j may be a helical baffle 26b. The helical baffle 26b extends along the central axis 17 and in a spiral shape within the enlarged portion 19 of the housing 16 about the central axis 17. The helical baffle 26b thus provides a helical shape for the meandering flow path 27. The helical shape of the meandering flow path 27 increases the residence time of the gaseous exhaust 10 within the enlarged portion 19 of the housing 16, thereby facilitating the capture and removal of contaminants from the gaseous exhaust 10 by the reactant mass 24 forming the helical baffle 26b. In one example, the helical baffle 26b is made of zinc. In another example, the helical baffle 26b is made of a material other than zinc that is coated with zinc. In yet another example, the helical baffle 26b is mechanically driven to rotate within the enlarged portion 19 of the housing 16 about the central axis 17. By rotating the helical baffle 26b, the flow of the gaseous exhaust 10 through the expansion 19 of the housing 16 can be artificially accelerated or decelerated depending on the direction of rotation of the helical baffle. The helical baffle 26b may be replaced and/or cleaned as needed if it becomes saturated during operation of the reverse venturi device 15.

7A-7B, at least one of the barrier elements 26a-26j is a plurality of baffles 26c. Each baffle 26c extends from an inner surface 68 of the enlarged portion 19 of the housing 16 across the enlarged portion 19 of the housing 16. The baffles 26c are spaced apart from one another along the central axis 17, and each baffle 26c has an orifice 28 that allows the flow of the gaseous exhaust 10 through the baffle 26c. Of course, any number of baffles 26c may be provided, including a configuration having only a single baffle 26c. The size, shape, and number of the orifices 28 in each baffle 26c may vary. For example, the baffles 26c may be screen-like, with the orifices 28 located between the crosshairs of the screen. The orifices 28 in the baffles 26c restrict the flow of the gas exhaust 10 within the enlarged portion 19 of the housing 16 and increase the residence time of the gas exhaust 10 within the enlarged portion 19 of the housing 16. This enhances the capture and removal of contaminants from the gas exhaust 10 by the reactant mass 24 forming the baffles 26c. In one example, the baffles 26c are made of zinc. In another example, the baffles 26c are made of a material other than zinc that is coated with zinc. The baffles 26c may be replaced and/or cleaned as needed if they become saturated during operation of the reverse venturi device 15. In yet another example, the size of the orifices 28 in one baffle 26c is different from the size of the orifices 28 in an adjacent baffle 26c. Using different size orifices 28 in different baffles 26c can accelerate and/or restrict the flow of the gas exhaust 10 and enhance the capture and removal of contaminants in the gas exhaust 10 by the reactant mass within the baffles 26c. Similarly, the baffles 26c do not have to be evenly spaced in the expansion chamber 21, and the orifices 28 of one baffle 26c do not have to be the same size, shape, or location as the orifices 28 of an adjacent baffle 26c. By varying the size, shape, and location of the orifices 28 from one baffle 26c to another, and by varying the spacing of the baffles 26c, the residence time of the gaseous exhaust 10 within the expansion 19 of the housing 16 can be increased to promote increased contact with physical and chemical entrapment and collection sites along the reactant mass 24.

In another configuration shown in Figures 8-11, at least one of the obstacles 26a-26j may not be fixed to the housing 16 itself, but may instead be freely positioned within the enlarged diameter portion 19 of the housing 16. In such a configuration, at least one of the obstacle elements 26a-26j may include obstacle media 26d-26j in various forms. Like the obstacle elements 26a-26c, the obstacle media 26d-26j may be made of zinc or may be made of a material other than zinc that is coated with zinc. Zinc is easily melted and can be cast into complex shapes using conventional molding methods, wax-loss methods, centrifugal methods, etc. Other forming methods include cutting, extrusion, sintering, stamping, hot forging and forming, laser cutting, etc. Alternatively, a prototype may be made of steel and then coated or plated with zinc as a surface cover. The obstruction media 26d-26j can be used to completely fill the entire expansion chamber 21, partially fill the expansion chamber 21, or fill between the baffles 26c described above in connection with Figures 7A-7B.

8 shows a configuration in which at least one of the obstruction elements 26a-26j is a plurality of pieces 26d housed within the enlarged diameter portion 19 of the housing 16. With this configuration, the gaseous discharge 10 passes through spaces between adjacent pieces 26d as the gaseous discharge 10 moves through the enlarged diameter portion 19 of the housing 16 from the inlet portion 18 of the housing 16 toward the outlet portion 20 of the housing 16. To this end, the plurality of pieces 26d may be of an irregular shape such that the pieces 26d are loosely packed within the enlarged diameter portion 19 of the housing 16. As a non-limiting example, the plurality of pieces 26d may be made of mossy zinc. Mossy zinc is a popcorn-shaped zinc structure produced by immersing molten zinc in a cooling liquid such as water. The resulting molten zinc droplets solidify into relatively small, spherical structures having a very large surface area to volume ratio. In addition, the surface area of the resulting structure has a mossy surface texture. These structures can be manufactured to size for specific applications. Steel can be machined to produce composite spherical structures of steel plates similar to Modified Zinc, which may be coated with zinc.

The loose packing of the fragments 26d in FIG. 8 creates a random shape for the meandering flow path 27, which increases the residence time of the gaseous exhaust 10 within the enlarged diameter portion 19 of the housing 16. This enhances the capture and removal of contaminants from the gaseous exhaust 10 by the reactant mass 24 forming the fragments 26d. The fragments 26d in FIG. 8 may be replaced and/or cleaned as needed if they become saturated during operation of the reverse venturi device 15.

In another configuration shown in FIG. 9, at least one of the obstruction elements 26a-26j is a plurality of entangled threads 26e housed within the enlarged portion 19 of the housing 16. The plurality of entangled threads 26e form a filament within the enlarged portion 19 of the housing 16. In one possible configuration, the plurality of entangled threads 26e are folded and rolled like steel wool to form a mass with a very large surface area. The entangled threads 26e themselves may be of the same composition, thickness and length, or may be a combination of different compositions, thicknesses and/or lengths. In one example, the plurality of entangled threads 26e are made of zinc wire and are randomly entangled to form zinc wool. The zinc wool can be manufactured from wires of various levels of density and/or size to impart specific flow restriction capabilities. In another example, the plurality of entangled threads 26e are made of steel wire and are randomly entangled to form steel wool. The steel wool may be coated with zinc. The loose packing of the entangled threads 26e in FIG. 9 creates a random shape for the meandering flow passage 27, which increases the residence time of the gaseous discharge 10 passing through the enlarged diameter section 19 of the housing 16. This promotes the capture and removal of contaminants in the gaseous discharge 10 by the reactant mass 24 forming the entangled threads 26e. The entangled threads 26e may be replaced and/or cleaned as needed if they become saturated during operation of the reverse venturi device 15.

10, another alternative configuration is shown in which the at least one of the elements 26a-26j is a filter element 26f. The filter element 26f extends across the enlarged portion 19 of the housing 16 relative to the central axis 17. The filter element 26f is porous, and the pores in the filter element 26f allow the gaseous exhaust 10 to pass through the filter element 26f as it flows through the enlarged portion 19 of the housing 16 from the inlet portion 18 to the outlet portion 20 of the housing 16. This configuration of the filter element 26f, which may be made of sintered metal, results in a random shape of the meandering flow path 27, which increases the residence time of the gaseous exhaust 10 passing through the enlarged portion 19 of the housing 16. This promotes the capture and removal of contaminants in the gaseous exhaust 10 by the reactant mass 24 forming the filter element 26f. The sintered metal of the filter element 26f is preferably made of zinc or a non-zinc material coated with zinc. This filter element 26f may be replaced and/or cleaned as necessary if it becomes saturated during operation of the reverse venturi device 15.

11, at least one obstruction element 26a-26j is shown as a combination of baffles 26c shown in FIGS. 7A-7B and fragments 26g-26j of different sizes similar to fragments 26d shown in FIG. 8. According to this alternative configuration, the baffles 26c and fragments 26g-26j are disposed within the enlarged portion 19 of the housing 16. Similar to FIGS. 7A-7B, the baffles 26c shown in FIG. 11 extend from the inner surface 68 of the enlarged portion 19 of the housing 16 across the enlarged portion 19 of the housing 16. Additionally, the baffles 26c are spaced apart from one another along the central axis 17 such that the baffles 26c divide the enlarged chamber 21 into multiple compartments. An orifice 28 in each baffle 26c allows the flow of the gaseous exhaust 10 through the baffle 26c. The multiple fragments 26g-26j are arranged between adjacent baffles 26c (i.e., within multiple compartments of the expansion chamber 21).

11 and 12A-12D, the reactant mass 24 is made up of a number of fragments 26g-26j. The fragments 26g-26j may be of different sizes and grouped together with the same size (i.e., fragments 26g, 26h, 26i, and 26j may be in different groups) and separated from the other size fragments by a baffle 26c. For example, the fragments 26g-26j may be arranged such that the size of the fragments 26g-26j decreases as they move away from the inlet 18 of the housing 16 and toward the outlet 20 of the housing 16. That is, the size of the fragments 26g-26j in each group may gradually change and decrease in the general flow direction of the gaseous discharge 10 in the enlarged portion 19 of the housing 16. In one example, the fragments 26g-26j are made of zinc. For example, pieces 26g-26j can be formed by dripping molten zinc into a cooling liquid to create popcorn-shaped structures with a very large surface area and random moss-like texture. In another example, pieces 26g-26j of different sizes can be mixed together and not separated based on size.

13A-13C show several alternatively shaped obstacle elements 26k-26m as non-compressible materials that can be used in addition to or instead of the multiple pieces 26d and 26g-26j shown in Figs. 8 and 11. Fig. 13A shows an example where the obstacle 26k forms the reactant mass 24 and has an asterisk shape similar to the children's toy "Jacks". Fig. 13B shows an example where the alternatively shaped obstacle elements 26k-26m are multiple crystal flakes 26l (only one shown) that form the reactant mass 24 and may be disposed in the enlarged portion 19 of the housing 16, similar to the pieces 26d and 26g-26j shown in Figs. 8 and 11. The crystal flakes 26l have a shape similar to a snowflake. FIG. 13C illustrates an example where the alternatively shaped obstruction elements 26k-26m are multiple wire coils 26m (only one shown) that form the reactant mass 24 and may be placed in the expansion 19 of the housing 16, similar to the pieces 26d and 26g-26j shown in FIGS. 8 and 11. The obstruction 26k and multiple crystal flakes 26l may be made of zinc or non-zinc materials that are coated with zinc using various processes, including but not limited to lost wax forging and 3D printing. The multiple wire coils 26m may be made, for example, by winding zinc wire around a spring-like mandrel core and then cutting the entire coil of wire along the entire length of the mandrel core to obtain rings of individual coils. The alternatively shaped obstruction elements 26k-26m may or may not completely fill the expansion chamber 21.

Various combinations of the above-mentioned various obstacle elements 26a-26k may be mixed. Examples of such mixed combinations include combining one or more baffles 26a-26c shown in Figures 5, 6A-6B, and 7A-7B with the multiple pieces 26d and 26g-26j shown in Figures 8 and 11. Another example of a mixed combination includes combining multiple entangled threads 26e shown in Figure 9 with the multiple pieces 26d and 26g-26j shown in Figures 8 and 11. Another configuration is possible that combines the above-mentioned various obstacle elements 26a-26k with other filter elements, such as activated carbon. Activated carbon, like a sponge, collects contaminants by surface contact. Thus, a limited amount of activated carbon may be introduced into the enlarged diameter portion 19 of the housing 16 to work with the above-mentioned various obstacle elements 26a-26k. Preferably, the obstruction elements 26a-26k hold the activated carbon within the enlarged section 19 of the housing 16 so that the activated carbon is relatively statically positioned throughout the enlarged chamber 21. This configuration is the opposite of typical emission control systems that release the activated carbon into the gaseous exhaust 10 flow. Because the activated carbon does not flow freely with the gaseous exhaust, more efficient use of the activated carbon is possible. Those skilled in the art will readily appreciate that the disclosed examples of the reverse venturi device 15 are merely exemplary and that numerous combinations beyond the few examples disclosed herein are possible and desirable to accommodate particular applications.

14, another exemplary reverse venturi device 15' is shown with two expansions 19, 19' connected in series by a conduit 38. One expansion 19 of the housing 16 extends between the inlet 18 of the housing 16 and the conduit 38, and the other expansion 19' extends between the conduit 38 and the outlet 20 of the housing 16. Thus, the tortuous flow path 27 of the gaseous effluent 10 is extended. With this configuration, the gaseous effluent 10 is directed from the expansion 19 through the conduit 38 to the expansion 19' where additional contaminants are collected and/or captured. The present disclosure is not limited to using only one or two expansions 19, 19' in series, as some applications involving large-scale emissions and/or high levels of contaminants may require numerous expansions connected in series.

15, another exemplary reverse venturi device 15'' is shown with two expansions 19, 19'' connected in parallel. A three-way inlet valve 39 controls the flow of the gas exhaust 10 and allows the gas exhaust 10 to flow into the conduit 41 or 42. A three-way outlet valve 40 allows the gas exhaust 10 to flow out of the conduit 41 or 42 without directly backflowing from the conduit 41 to the conduit 42 or from the conduit 42 to the conduit 41. The gas exhaust 10 flows from the inlet 18 into the expansion 19 and out of the outlet 20 when the gas exhaust 10 is sent from the conduit 41. The gas exhaust 10 flows from the inlet 18'' into the expansion 19'' and out of the outlet 20'' when the gas exhaust 10 is sent from the conduit 42. One advantage of the reverse venturi device 15'' shown in FIG. 15 is that if one of the expansions 19, 19'' requires maintenance, repair, or cleaning, it can be isolated and taken offline without shutting down the entire system, since the other expansion 19, 19'' can remain operational.

Over time, chemical reactions occurring on the outer reactant surface 25 of the reactant mass 24 and/or physical entrapment of contaminants can cause the reactant mass 24 to reach a saturation point, reducing the efficiency of the reverse venturi device 15. Thus, the configuration shown in FIG. 15 allows the reactant mass 24 within the enlarged diameter portions 19, 19'' of the housing 16 to be removed, replaced and/or cleaned, restoring the reverse venturi device to its pre-saturation efficiency without a complete shutdown.

The process of removing contaminants from the saturated reactant mass depends on the specific type of contaminant and the type of amalgam-forming metal used. Access to the expansion chamber 21, 21'' located within the expansion 19, 19'' of the housing 16 depends on the type of obstruction used. If a relatively small, non-compressible obstruction is used, pouring and/or draining type access is required. If the obstruction is a relatively large block, plate, baffle or assembly, appropriate lifting and handling methods and access are required.

15, the inverted venturi device 15 may include one or more spray nozzles 81 in fluid communication with the enlarged portion 19, 19'' of the housing 16. The spray nozzles 81 are positioned to inject deoxidizing acid onto the reactant mass 24 within the enlarged portion 19, 19'' of the housing 16. In operation, the deoxidizer flushes contaminants from the reactant mass 24 to activate the reactant mass 24. Alternatively, a drain 82 may be in fluid communication with the enlarged portion 19, 19'' of the housing 16 to carry spent deoxidizer and contaminants away from the enlarged portion 19, 19'' of the housing 16. Saturated zinc, whether coated on steel or in a solid zinc structure, is preferred in that it can be recycled and reused. Thus, the materials used in the obstruction can be reused. Additionally, many of the captured contaminants, especially heavy metals such as mercury, can be reused for lighting and chlorine production.

16, another exemplary reverse venturi device 15 is shown in which the expansion chamber 45 has a volume that is significantly larger than the volume of the inlet conduit 43 and the outlet conduit 44. The expansion 46 may be circular, square, triangular, elliptical, or virtually any one of a number of shapes desired to provide an enlarged, tortuous flow path 77 for the gaseous exhaust flowing through the expansion 46 (a rectangular shape is shown).

Referring to FIG. 17, a block diagram of a typical gaseous emission control system is shown. The gaseous emission is introduced from a furnace 47 to an electrostatic precipitator (ESP) 48, a fluidized gas desulfurization (FGD) unit 49, and a fabric filter (FF) unit 50 before being discharged to the atmosphere via a chimney 51. A first concentration of pollutants 52 is removed from the gaseous emission in the ESP 48. Similarly, a second concentration of pollutants 53 is removed from the gaseous emission in the FGD unit 49. The second concentration 53 produced by the FGD unit 49 often contains mercury and other heavy metals and typically flows into the wastewater. A third concentration of pollutants 54 is removed from the gaseous emission in the FF unit 50.

Finally, the final emissions discharged to the atmosphere may still not meet EPA emission rules and regulations. An EPA sanctionable emission requires that at least 90% of harmful pollutants be removed, whereas current common emission control systems can only remove 88-90% of harmful pollutants. A major problem for industries that produce polluting emissions is that regulations governing emissions are becoming more stringent over time, while current emission control technologies are potentially reaching their limits. Thus, the current pace of technological advances cannot keep up with the pace of ever-tightening emission regulations.

18A-18B, the block diagram of FIG. 17 is modified in that an adsorbent injection point is introduced and an additional step is provided where the gaseous effluent passes through the above-mentioned reverse venturi device 15. In FIG. 18A, a first adsorbent introduction point 55 is shown between the furnace 47 and the ESP 48. Alternatively, in FIG. 18B, a second adsorbent introduction point 56 is shown between the FDG unit 49 and the FF unit 50. Which option is considered the most favorable for the adsorbent depends on the existing structure and plant conditions. There are many more introduction points or combinations of introduction points where the adsorbent can be introduced than the two options shown in FIG. 18A-18B, and therefore these two options are shown for illustrative purposes. The reverse venturi device 15 in FIG. 18A-18B is placed after the FF unit 50 and before the chimney 51. This reverse venturi device 15 may be constructed according to any of the above-mentioned examples as appropriate for various applications. Ultimately, the final gas emissions exiting the reverse venturi device 15 and released to the atmosphere through the stack 51 will be able to meet and exceed current and future EPA emissions rules and regulations.

18A-18B includes burning fuel in a furnace 47 to generate a gaseous effluent containing pollutants, flowing the gaseous effluent from the furnace 47 into an ESP 48, and using the ESP 48 to remove a first portion of particulate pollutants from the gaseous effluent. Using the ESP 48 to remove a first portion of particulate pollutants from the gaseous effluent forms a first condensate 52 that includes a first portion of the particulate pollutants removed from the gaseous effluent by the ESP 48. In operation, the ESP 48 removes fine pollutants from the gaseous effluent using an applied electrostatic charge. The method also includes introducing the gaseous effluent from the ESP 48 into an FDG unit 49 and using the FDG unit 49 to remove sulfur dioxide pollutants from the gaseous effluent. Using the FDG unit 49 to remove sulfur dioxide pollutants from the gaseous effluent forms a second condensate 53 that includes the sulfur dioxide pollutants removed from the gaseous effluent by the FDG unit 49. The method further includes introducing the gaseous exhaust from the FDG unit 49 into a FF unit 50 (i.e., baghouse) and removing a second portion of the particulate contaminants in the gaseous exhaust using the FF unit 50. The step of removing a second portion of the particulate contaminants in the gaseous exhaust using the FF unit 50 forms a third concentrate 54 that includes the second portion of the particulate contaminants removed from the gaseous exhaust by the FF unit 50. In operation, contaminant particles are removed from the gaseous exhaust as the gaseous exhaust passes through one or more fabric filters (not shown) in the FF unit 50.

According to the present disclosure, the method further includes the step of directing the gaseous effluent from the FF unit 50 to an inverted venturi device 15 and removing heavy metal contaminants in the gaseous effluent using the inverted venturi device 15. The step of removing heavy metal contaminants in the gaseous effluent using the inverted venturi device 15 causes the gaseous effluent to pass through (i.e., flow over) a reactant mass disposed in the inverted venturi device 15. Amalgam-forming metals in the reactant mass chemically combine with the heavy metal contaminants in the gaseous effluent. Thus, the heavy metal contaminants in the inverted venturi device 15 are captured by the reactant mass as they combine with the amalgam-forming metals in the reactant mass. The method further includes directing the gaseous effluent from the inverted venturi device 15 to a chimney 51 that releases the gaseous effluent to the surrounding atmosphere. The reverse venturi device 15 has the advantage that it has a relatively small footprint and can be easily integrated and installed between the emission control devices 48, 49, 50 of an existing system and the stack 51 to the atmosphere.

The method may include a step of injecting a sorbent into the gaseous effluent. According to this step, the sorbent may be injected into the gaseous effluent at a first sorbent introduction point 55 located between the furnace 47 and the ESP 48, as shown in FIG. 18A. Alternatively, the sorbent may be injected into the gaseous effluent at a second sorbent introduction point 56 located between the FDG unit 49 and the FF unit 50, as shown in FIG. 18B. The sorbent includes amalgam-forming metals and binds at least a portion of the heavy metal contaminants in the gaseous effluent before the gaseous effluent enters the inverse venturi device 15. By injecting the sorbent into the gaseous effluent at the first sorbent introduction point 55 or the second sorbent introduction point 56, more mercury, heavy metals, and acid gases can be collected in the FF unit 50 at levels not previously achievable. As mentioned above, the amalgam-forming metals may be selected from the group consisting of zinc, iron, and aluminum, and the sorbent may be, for example, a CZTS compound. The adsorbents can be regenerated and activated so that harmful pollutants can be captured and recycled.

19, a block diagram of a typical non-gaseous effluent control system is shown. Liquid and/or liquid-like effluent is sent from a fluidized gas desulfurization (FGD) unit 59 and/or from a wet gas scrubber 58 to a lime treatment unit 60 before being sent to a settling pond 61. After a suitable time, the non-gaseous effluent is sent from the settling pond 61 into a treatment system or dewatering system 62 for preparation of a dry waste 64. The non-gaseous effluent sent through the treatment of the dry waste 64 is prepared for disposal in a disposal site 65. The non-gaseous effluent sent through the dewatering system 62, possibly with a recirculation system, is prepared for use in a secondary industrial process 63, which may include, for example, gypsum and/or cement manufacturing. The non-gaseous effluent not sent from the settling pond 61 to the dewatering system 62 or treatment for the dry waste 64 is sent to be discharged through a drain 66. The final non-gaseous effluent discharged to the drain 66 is not regulated as it will be in the future years. The proposed EPA water effluent rules and regulations are highly restrictive compared to what can currently be discharged down the drain. Industries that are required to discharge polluted liquid effluents down the drain have current discharge control technology that is virtually incapable of meeting and/or complying with upcoming EPA regulations.

Referring to FIG. 20, the block diagram of FIG. 19 is modified by one or more treatment tanks 67 containing the adsorbents described above. The treatment tanks 67 are placed after the non-gaseous effluents are sent from the settling tank 61 and before they are discharged to the drain 66. The method shown in FIG. 20 includes the steps of collecting the non-gaseous effluent containing pollutants, passing the non-gaseous effluent through an FGD unit 59 and/or a wet scrubber 58 to remove some of the pollutants in the non-gaseous effluent, sending the non-gaseous effluent from the FGD unit 59 and/or the wet scrubber 58 to a lime treatment unit 60, and passing the non-gaseous effluent through the lime treatment unit 60 to soften the non-gaseous effluent by the Clark process. In operation, the lime treatment unit 60 removes certain ions (e.g., calcium (Ca) and magnesium (Mg)) from the non-gaseous effluent by precipitation. The method also includes the steps of: sending the non-gaseous effluent from the lime processing unit 60 to a settling pond 61, settling and removing a portion of the contaminants in the non-gaseous effluent; dewatering a first portion of the non-gaseous effluent in the settling pond 61; using the dewatered by-product in a secondary industrial process 63; removing a second portion of the non-gaseous effluent from the settling pond 61; and applying a dry waste treatment 64 to the second portion of the non-gaseous effluent. In the steps of dewatering the first portion of the non-gaseous effluent in the settling pond 61 and using the dewatered by-product in a secondary industrial process 63, the dewatering step may include recycling the first portion of the non-gaseous effluent, which may include, for example, a gypsum or cement manufacturing process. In the steps of removing the second portion of the non-gaseous effluent from the settling pond 61 and applying a dry waste treatment 64 to the second portion of the non-gaseous effluent, the dry waste treatment 64 may include depositing the second portion of the non-gaseous effluent in a waste site 65.

As disclosed herein, the method further includes the step of passing a third portion of the non-gaseous effluent in the settling basin 61 to a treatment vessel 67 containing a disclosed sorbent. The sorbent includes an amalgam-forming metal that binds with heavy metal contaminants in the non-gaseous effluent. Thus, the sorbent captures heavy metal contaminants in the treatment vessel 67 as the heavy metal contaminants bind to the sorbent and precipitate/deposit from the non-gaseous effluent. The method may then pass the non-gaseous effluent from the treatment vessel 67 to a drain 66 for discharge. The treatment vessel 67 may be designed to allow a continuous flow of the non-gaseous effluent (i.e., a wastewater stream) from the treatment vessel 67.

Several exemplary embodiments of the adsorbents disclosed herein are disclosed. These exemplary embodiments are merely examples and are not intended to be an exhaustive list of all possible variations on this theme.

As mentioned above, one exemplary sorbent is elemental zinc powder. Zinc powder consists of elemental zinc. The zinc may be used as a powder or as granules. One method used to extend the useful life and reduce and/or prevent pre-oxidation of zinc powder and/or granules used in any gaseous effluent at high temperatures is to mix or coat the granules and/or powder with a solid acid, such as sulfamic acid, citric acid, and other organic acids. This powder/acid mixture may be injected into the gaseous effluent (e.g., flue gas stream) and/or placed in an appropriate embodiment of the inverse venturi device 15.

The optimum particle size for zinc powder is in the range of 0.5 nanometers to 7,500 microns. Additionally, it has been found that powder mixtures having different particle size ranges are advantageous, particularly when the particle size range is 0.5 nanometers to 7,500 microns. Similarly, the optimum particle size for zinc granules is in the range of 7,500 microns to 3.0 inches. Additionally, it has been found that powder mixtures having different particle size ranges are advantageous, particularly when the particle size range is 7,500 microns to 3.0 inches.

In another exemplary embodiment, the adsorbent is CZTS, with the molecular formula Cu2ZnSnS4. CZTS may advantageously be composed of other phases of copper, zinc, tin, and sulfur. CZTS and/or associated phases of copper, zinc, tin, and sulfur may be mixed in stoichiometric ratios followed by mechanochemical blending in a mill. Additionally, the CZTS may be mixed with either clay, such as bentonite or zeolite, in equal proportions, and calcium hydroxide (CaOH). The optimal particle size of the CZTS powder ranges from 0.5 nanometers to 7,500 microns. During testing and development, it has been found that CZTS powder mixtures with different size particle size ranges are advantageous, especially when the particle size range is from 0.5 nanometers to 7,500 microns. For applications where specialized CZTS granules are preferred, the optimal particle size has been found to be in the range of 7500 microns to 3.0 inches. Additionally, mixtures of CZTS granules having different size particle size ranges have been found to be advantageous, particularly in the particle size range of 7,500 microns to 3.0 inches.

For most contaminants, CZTS is most effective at the smallest particle size within the ranges mentioned above, with a large amount of metallic CZTS present. Note that during the production of CZTS, copper, zinc, tin and sulfur are not completely converted to CZTS, but rather result in a mixture of phases (e.g., danbanite (CuZn2) and tin sulfide (SnS)).

In one exemplary method for producing CZTS, copper, zinc, tin, and sulfur are added to a mill in no particular order. The milling process can be accomplished using a ball mill or some type of attrition mill, or a combination of milling devices used sequentially to obtain the desired particle size. Exemplary particle sizes range from 325 standard mesh screen to 100 standard mesh screen (1 standard mesh screen=7500 microns). The resulting particles are then weighed to a predetermined molar ratio of copper:zinc:tin:sulfur=1.7:1.2:1.0:4.0. After verifying the mesh size and molar ratio, the particles are milled and mechanochemically compounded into CZTS and other phases. The milling time is controlled to provide optimal properties for the specific application. The milling process can be performed using a wet milling process with the addition of a suitable solvent such as glycol ether, ethylene glycol, ammonia, or other alcohols in an inert gas atmosphere, or a dry milling process in an inert gas atmosphere.

During the milling process, samples are taken intermittently to determine particle size using a particle size analyzer, SEM, XRD, or to determine phase transformation ratio using Raman techniques. The mill ball size is important and testing has shown it to be optimized when the ball-to-powder weight ratio (charge ratio) is at least 5:1. Most preferably, the mill balls are made of steel, ceramic, zirconia, or other material that achieves size and/or phase transformation without contaminating the final product. If wet milling is employed, the CZTS is dried. The CZTS is then mixed with the bentonite or zeolite and calcium hydroxide using a ribbon blender, V-blender, or other suitable mixer to mix evenly.

According to the above-described method, the sorbent is introduced into the gaseous effluent at a temperature of approximately 750° F. or less. The sorbent is introduced into the gaseous effluent by any of several methods, including, but not limited to, injection, fluidized bed, coated filter, and capture. The method of introduction can be selected based on existing emission control systems in the plant and for ease of installation. One convenient method is to inject CZTS into the gaseous effluent instead of activated carbon, and the same injection equipment can be used with or without modification.

In some applications, the treatment of gaseous effluents is optimized when CZTS is mixed with bentonite to effectively remove pollutants. Alternatively, the treatment of non-gaseous effluents is optimized when CZTS is mixed with zeolite. The particular materials mixed with CZTS as well as the ratios of the mixtures can be application specific to provide optimal pollutant removal capabilities.

18A-18B, when CZTS is used for gaseous effluent treatment, a fabric filter unit 50 is placed downstream of the CZTS introduction point 55, 56 to capture the sorbent particles and increase the contact time between the gaseous effluent and the sorbent. The sorbent is deposited on the fabric filter (i.e., bag) of the fabric filter unit 50 to allow for longer contact between the gaseous effluent and the sorbent, and the sorbent can be collected and subsequently regenerated. The small particle size of the sorbent allows it to be carried along with the gaseous effluent flow, much like dust is carried by the wind. During the period in which the sorbent is carried in the gaseous effluent flow, the sorbent comes into contact with the contaminants moving in the gaseous effluent flow, which causes the contaminants to chemically react and bond with the sorbent. Upon reaching the fabric filter unit 50, the gaseous effluent continues to pass through the filter in the fabric filter unit 50, while the combined sorbent and contaminant particles are too large to pass through the filter. If the CZTS particles are 10 microns or smaller, it may be necessary to pre-coat the filter in the fabric filter unit 50 with larger CZTS particles, activated carbon, talc, lime, or other suitable material to prevent the smaller CZTS particles from passing through the filter. Alternatively, a smaller micron-sized filter may be used in the fabric filter unit 50.

In other applications for non-gaseous effluents, the CZTS may be introduced into a treatment tank 67 as shown in FIG. 20. In this configuration, the CZTS is preferably introduced into the treatment tank 67 and agitated for a period of time, after which the non-gaseous effluent (e.g., wastewater) is subjected to pH adjustment, flocculation, and filtration before being discharged. The CZTS in the treatment tank 67 may then be subjected to a regeneration step to remove contaminants from the CZTS. The spent CZTS can be regenerated by filtering the mercury from the CZTS or by vacuum distillation. The resulting contaminants can then be utilized in other industries. CZTS also provides the advantage of being able to reduce nitrate and nitride levels in the non-gaseous effluent.

The wastewater regulations established by the EPA, effective in 2016, are much stricter than those for air. Some of the current EPA regulations, listed in nanograms/liter (ng/L), micrograms/liter (ug/L), and/or grams/L, are: mercury 119 ng/L, arsenic (As) 8 ug/L, selenium (Se) 10 ug/L, nitrogen dioxide (NO2) and nitrates (NO3) 0.13 g/L. Other heavy metals such as lead (Pb) and cadmium (Cd) are also included in the proposed EPA regulation levels. Many existing plants send wastewater with pollution levels that exceed the allowable discharge regulations to retention ponds and/or some other type of sludge holding tank. CZTS can treat solids in retention ponds in the same way that it treats non-gaseous effluents as disclosed herein. Depending on the ionic form of the heavy metals, the sludge composition and/or the pH, the contact time of the CZTS in the basin can be appropriately adjusted. Sufficient pH adjustment, flocculation, and subsequent filtration allow for normal discharge, disposal, and/or use in other industries, none of which was previously possible.

It is noted that the adsorbents disclosed herein, including activated carbons currently used in the industry, do not contain any free carbon. As a result, none of the metal sulfides produced as by-products of the disclosed methods are filtered out. These by-products are therefore of high commercial value in gypsum wallboard and cement applications. The EPA's metal sulfide filtration tests are known and well documented for use in these products.

Activated carbon is available in several alternative configurations, but the limited use of activated carbon in these variations does not allow the activated carbon to leak into the effluent. For example, in one example, the activated carbon is embedded in the filter of the fibrous filter unit 50. The activated carbon does not leak freely into the gaseous effluent stream. Another limited use of activated carbon is to coat the crystalline form of CZTS with activated carbon to produce CZTS with a carbon film that is 1.0 nanometer or less thick. This promotes the capture of extremely small mercury metal vapor particles. Similarly, the crystalline CZTS can be coated with a nanometer zeolite film or other coating to target specific harmful pollutants for specific applications. Again, the activated carbon in this variation does not leak freely into the gaseous effluent stream.

Referring to FIG. 21, a graph is shown showing the percentage of pollutants removed from the exhaust by known emission control systems and the percentage of pollutants removed by the inverted venturi device and method disclosed herein. A 90% pollutant level 78 is currently established for gaseous exhaust by the EPA. Existing emission control systems 79 are effective at removing 88% to 90% of harmful pollutants. However, the EPA has been increasing the required minimum pollutant removal percentages for several years, and many existing emission control systems are unable to meet this requirement, and many other existing emission control systems are only able to meet the requirement when operating at the maximum removal capacity available under current technology.

21, the exemplary emission control system 80 is a new emission control system based on the inverted venturi device, adsorbents and/or methods disclosed herein, or an existing emission control system that has been modified and augmented to include the inverted venturi device, adsorbents and/or methods disclosed herein. Testing has confirmed that the exemplary emission control system 80 is capable and effective at removing at least 98% of harmful pollutants, well above current EPA regulatory levels.

22 and 24, an example of an emission control method is illustrated. According to this, a contaminated gas source 150 is introduced into the system, passes through one or more fluidized bed pre-filters 151, a fluidized bed 152, one or more fluidized bed post-filters 153, and a system side exhaust 154, and the gaseous emissions are released through a chimney 155 due to environmental regulation emissions. It is noted that it is not always necessary to pass the contaminated gas source 150 through one or more fluidized bed pre-filters 151 first, but one or more fluidized bed pre-filters 151 may be required depending on the requirements of a particular application.

The fluidized bed 152 has an inverted venturi shape with a specific length L to diameter D ratio of at least 2.9:1 and at most 9.8:1. This ratio is optimized to extend the residence time of the contaminated gas source 150 in the fluidized bed 152 loaded with a special adsorbent, such as reactant 164, which is an adsorbent made of copper zinc tin sulfide (CZTS) compounds and/or alloys thereof. A preferred length L to diameter D ratio for the fluidized bed 152 is 4.4:1, which was determined by trial and error testing.

Preferably, the fluidized bed 152 has a generally curved cross-section. Although not shown in FIG. 24, the fluidized bed 152 can incorporate one or more of various baffles and/or other application-specific flow-restricting obstacles disclosed herein. The fluidized bed 152 also features generally outwardly extending convex ends 168 and 169 to extend residence time and minimize turbulence through the reactants 164. When the flow of the contaminated gas source 150 enters the fluidized bed 152 through the inlet 165, it first comes into intimate contact with the reactants 164, resulting in random non-turbulent flow 166. The random non-turbulent flow 166 reverses itself through the generally outwardly extending convex ends 168 and 169, resulting in an extended residence time in the fluidized bed 152 before the non-turbulent flow 166 exits the fluidized bed 152 through the outlet 167. The reactants 164 promote random non-turbulent flow 166, creating a randomly meandering flow path for the contaminated gas source 150. Note that the length L of the fluidized bed 152 does not include the convex ends 168 and 169.

The fluidized bed 152 has a side outlet 170 leading to a sorbent wash station 156, which may remove spent sorbent 157 from the system for disposal. Additionally, contaminants 158 captured from the gas source 150 contaminated by reactants 164 and separated from the reactants 164 in the sorbent wash station 156 may be disposed of and/or recycled. The sorbent wash station 156 allows the washed reactants 164 to be returned to the fluidized bed 152 through the sorbent return port 159. The bulk replenishment sorbent container 168 allows the reactants 164 to be replenished as needed to replace the removed spent sorbent 157. The system side exhaust 154 allows the gaseous effluent to be discharged through the exhaust stack 155 for release under environmental regulations. Additionally, the captured waste 160 may be discharged.

23 and 24, an example of emission control is illustrated. According to this, when a contaminated non-gaseous source 161 is introduced into the system, it passes through one or more fluidized bed pre-filters 151, a fluidized bed 152, one or more fluidized bed post-filters 153, and a system side exhaust 154, and the non-gaseous emissions are released by environmental regulation release 162. It is noted that it is not always necessary to pass the contaminated non-gaseous source 161 first through one or more fluidized bed pre-filters 151, but one or more fluidized bed pre-filters 151 may be required depending on the requirements of a particular application.

The fluidized bed 152 has an inverted venturi shape with a specific length L to diameter D ratio of at least 2.9:1 and at most 9.8:1, which is optimized to extend the residence time of the contaminated non-gaseous source 161 in the fluidized bed 152 loaded with a special adsorbent, such as reactant 164. The reactant 164 is an adsorbent made of copper zinc tin sulfide (CZTS) compounds and/or alloys thereof. A preferred length L to diameter D ratio for the fluidized bed 152 is 4.4:1, which has been determined by trial and error testing.

Preferably, the fluidized bed 152 also features generally outwardly extending convex ends 168 and 169 to enhance residence time and minimize turbulence through the reactants 164. As the flow of contaminated non-gaseous source 161 enters the fluidized bed 152 through the inlet 165, it first comes into intimate contact with the reactants 164, resulting in random non-turbulent flow 166. The random non-turbulent flow 166 is reversed by the generally outwardly extending convex ends 168 and 169, resulting in an extended residence time in the fluidized bed 152 before the random non-turbulent flow 166 exits the fluidized bed 152 through the outlet 167. The reactants 164 promote the random non-turbulent flow 166 and create a randomly tortuous flow path for the contaminated gas source 161. Note that the length L of the fluidized bed 152 does not include the convex ends 168 and 169.

Preferably, the fluidized bed 152 has a generally curved cross-section. Although not shown in FIG. 24, the fluidized bed 152 can incorporate one or more of various baffles and/or other application-specific flow-restricting obstacles disclosed herein. The fluidized bed 152 has a side outlet 170 leading to a sorbent washing station 156. The sorbent washing station 156 may remove spent sorbent 157 from the system for disposal. Additionally, contaminants 158 captured from the non-gaseous source 161 contaminated by reactants 164 and separated from the reactants 164 in the sorbent washing station 156 can be disposed of and/or recycled. The sorbent washing station 156 can return the washed reactants 164 to the fluidized bed 152 through a sorbent return port 159. A bulk replenishment sorbent container 168 allows the reactants 164 to be replenished as needed to replace the removed spent sorbent 157. The system side exhaust 154 allows for non-gaseous exhaust with release 162 based on environmental regulations. In addition, it allows for the exhaust of captured waste 163.

It should be noted that although the steps in the method are described and illustrated in a particular order, the steps may be performed in a different order without departing from the scope of the present disclosure, unless the order of the steps is otherwise described. Similarly, the method described and illustrated herein may be performed without including all of the steps described above or with additional intermediate steps not described, without departing from the scope of the present disclosure.

It will be apparent that the present invention is susceptible to numerous modifications in light of the above disclosure and may be practiced otherwise than as specifically described within the scope of the appended claims. These prior descriptions should be construed to cover any combination in which inventive novelty is available. The use of the word "the" in an apparatus claim indicates antecedent basis that is a positive statement intended to be included within the scope of the claim, but the word "the" precedes terms that are not intended to be included within the scope of the claim.

Claims (11)

1. A fluidized bed apparatus for removing contaminants from an effluent, comprising:
a housing having an inverted venturi shape and including an inlet portion through which the exhaust flows at a predetermined inlet flow rate, an outlet portion through which the exhaust flows at a predetermined outlet flow rate, and an expanded diameter portion disposed between the inlet portion and the outlet portion and configured to capture the contaminants in the exhaust,
the inlet portion, the outlet portion, and the expanded diameter portion of the housing are in fluid communication with one another;
the length of the expansion is greater than its diameter, the ratio of the length to the diameter being greater than or equal to 2.9:1 and less than or equal to 9.8:1;
a reactant mass is disposed within the enlarged diameter portion of the housing;
the reactant mass having a reactive outer surface disposed in contact with the effluent, and the reactant mass comprising an alloy of copper , zinc, tin, sulfide (CZTS) compounds;
the reactant mass includes an amalgam-forming metal on its outer surface that chemically bonds with at least a portion of the contaminants in the effluent that reach the reactant mass's outer surface through the enlarged diameter portion of the housing;
the housing has a side outlet leading to a sorbent washing station and a sorbent return port;
the sorbent washing station is adapted to introduce the reactant mass from the housing through the side outlet, to separate the contaminants from the reactant mass and to wash the reactant mass, and to inject the washed reactant mass back into the housing through the sorbent return port for recycling;
the reactant mass is disposed within the enlarged portion of the housing and defines at least one obstruction element that defines a tortuous flow path for the effluent passing through the enlarged portion of the housing;
11. A fluidized bed apparatus comprising: said effluent serving as a fluid in a fluidized bed; and said reactant mass being fluidized within said expansion section for removing said contaminants from said effluent. The fluidized bed apparatus according to claim 1, characterized in that the enlarged diameter portion has a circular cross section. 3. The fluidized bed apparatus of claim 2, wherein the ratio of said length to said diameter of said expansion is 4.4:1. 2. The fluidized bed apparatus of claim 1, wherein said enlarged diameter section has outwardly extending convex ends. 1. An emission control method for removing heavy metal contaminants from a non-gaseous emission, comprising:
passing the non-gaseous effluent to a treatment system including an inverted venturi fluidized bed device including a sorbent comprising an alloy of copper , zinc, tin, sulfide (CZTS) compounds, the sorbent being a reactant that chemically binds with the heavy metal contaminants carried by the non-gaseous effluent, and an expansion in which the sorbent is disposed;
passing the non-gaseous effluent through a tortuous flow path defined by at least one obstruction element disposed within the inverted venturi fluidized bed apparatus, the obstruction element containing the adsorbent;
allowing the reactants contained within the inverted venturi fluidized bed device to capture the heavy metal contaminants;
directing the non-gaseous effluent from which the heavy metal contaminants have been removed away from the inverted venturi fluidized bed apparatus;
discharging the adsorbent from a side outlet in the inverted venturi fluidized bed apparatus;
separating the heavy metal contaminants from the adsorbent discharged from the side outlet to produce a washed adsorbent;
and injecting the washed adsorbent into the inverted venturi fluidized bed apparatus through an adsorbent return port provided in the inverted venturi fluidized bed apparatus to recycle the washed adsorbent.
the non-gaseous effluent serves as a fluid in a fluidized bed, and the adsorbent is a fluidized bed within the expansion for removing the heavy metal contaminants from the non-gaseous effluent;
13. The method of claim 12, wherein a ratio of a length of the expansion along a direction of flow of the non-gaseous effluent to a diameter of the expansion is greater than or equal to 2.9:1 and less than or equal to 9.8:1. 6. The method of claim 5, wherein the inverted venturi fluidized bed apparatus includes an expansion having a circular cross section, the expansion having a length greater than its diameter. 7. The method of claim 6, wherein the ratio of said length to said diameter of said expansion is 4.4:1. 6. A method for controlling emissions as claimed in claim 5, comprising:
and disposing of the heavy metal contaminants separated from the adsorbent discharged from the side outlet. 1. A method for emission control for removing heavy metal contaminants from a gaseous effluent, comprising:
passing the gaseous effluent to a treatment system comprising an inverted venturi fluidized bed device including a sorbent comprising an alloy of copper , zinc, tin, sulfide (CZTS) compounds, the sorbent being a reactant that chemically binds with the heavy metal contaminants carried by the gaseous effluent, and an expansion in which the sorbent is disposed;
passing the gaseous effluent through a tortuous flow path defined by at least one obstruction element disposed within the inverted venturi fluidized bed apparatus, the obstruction element containing the adsorbent;
allowing the reactants contained within the inverted venturi fluidized bed device to capture the heavy metal contaminants;
directing the gaseous effluent from which the heavy metal contaminants have been removed away from the inverted venturi fluidized bed apparatus;
discharging the adsorbent from a side outlet in the inverted venturi fluidized bed apparatus;
separating the heavy metal contaminants from the adsorbent discharged from the side outlet to produce a washed adsorbent;
and injecting the washed adsorbent into the inverted venturi fluidized bed apparatus through an adsorbent return port provided in the inverted venturi fluidized bed apparatus to recycle the washed adsorbent.
the gaseous effluent serves as a fluid in a fluidized bed, and the adsorbent is a fluidized bed within the expansion for removing the heavy metal contaminants from the gaseous effluent;
13. The method of claim 12, wherein a ratio of a length of the expansion along a direction of flow of the gaseous emissions to a diameter of the expansion is greater than or equal to 2.9:1 and less than or equal to 9.8:1. 10. The method of claim 9 , wherein the ratio of the length to the diameter of the expansion is 4.4:1. 10. A method for controlling emissions as claimed in claim 9 , comprising:
and disposing of the heavy metal contaminants separated from the adsorbent discharged from the side outlet.

Images