CN205102149U - Multiple gas cleaning is demercuration device in coordination - Google Patents

Abstract

The utility model discloses a multiple gas cleaning is demercuration device in coordination, including clean coal device, boiler, SCR denitrification facility, dust remover and FGD desulphurization unit, the discharge gate of clean coal device is connected to the feed inlet of boiler, and the floss hole of boiler is connected to SCR denitrification facility's input port, and SCR denitrification facility's delivery outlet is connected to dry dust collector, and dry dust collector exports FGD desulphurization unit to. The beneficial effects of the utility model are that: 1 )The organic integration of technique is progressively in coordination with desorption mercury. 2 )Equipment compatibility and operational safety are good. 3 )Adaptability is good.

Description

A variety of flue gas purification and mercury removal devices

technical field

The utility model belongs to a purification synergistic mercury removal device, and more specifically relates to a plurality of flue gas purification synergistic mercury removal devices.

Background technique

According to the prediction of the World Energy Conference, the status of coal as an important part of primary energy will not change for a long time. It is estimated that coal will account for 33.7% of the world's primary energy consumption in 2020. my country is a large country of coal production and use. In 2011, coal provided 68.8% of my country's primary energy. Coal-fired power plants are the sector with the largest coal consumption in my country, and for a long period of time in the future, my country will continue to maintain its power structure. The basic pattern of coal-fired power plants. With the development of the economy, the demand and supply of electricity continue to grow, and the installed capacity of coal-fired power plants has been rising rapidly, resulting in high emissions of air pollutants and an increasingly serious impact on the ecological environment.

Coal-fired power plants are major sources of emissions of air pollutants such as soot, sulfur dioxide (SO2) and nitrogen oxides (NOX). In recent years, my country has formulated a series of laws and regulations, standards, plans, technical policies, etc., which put forward higher and higher requirements for the emission control of air pollutants in coal-fired power plants. Air pollutants such as smoke, SO2 and NOX Some achievements have been made in governance. Electric dust removal technology and limestone-gypsum wet desulfurization technology have been widely used. With the release of the new "Emission Standard of Air Pollutants for Thermal Power Plants" (GB13223-2011) in 2011, efficient dust removal technology and selection Sexual catalytic reduction (SCR) denitrification technology will also be widely used. According to statistics, by the end of 2012, the capacity of flue gas desulfurization units put into operation across the country was 680 million kilowatts, accounting for 89% of the capacity of coal-fired power units, and more than 90% of the flue gas desulfurization devices used limestone-gypsum wet desulfurization technology; The capacity of the flue gas denitrification unit is about 230 million kilowatts, accounting for 28% of the thermal power unit capacity, and more than 95% of the denitrification devices use SCR denitrification technology.

Mercury emissions have drawn great attention from governments and environmental protection organizations. Mercury is a heavy metal pollutant with strong biological toxicity in the environment. It is difficult to be excreted after entering the organism, which seriously threatens human health. The United Nations Environment Program (UNEP) pointed out that coal-fired power plants are the largest source of man-made mercury pollution, accounting for about 67% of global mercury emissions, so controlling mercury emissions from coal-fired power plants is very urgent.

With the improvement of people's awareness of environmental protection and the deepening of understanding, regulations on mercury emissions are also gradually introduced. After the U.S. enacted the Clean Air Act (CAAA) in 1990 and mercury pollution emissions received great attention, governments of various countries have also paid great attention to the status quo of mercury pollution. If all goes well, the governments of various countries, including China, are expected to reach an international mercury pollution control convention in 2013. After the 18th National Congress of the Communist Party of China, in the latest ruling program, the content of building an ecological civilization and a beautiful China has been written, and special requirements have been put forward for the control of air pollution, and it is an independent chapter.

According to statistics, as of the end of 2012, my country's coal-fired power plants emit about 150 tons of mercury into the atmosphere every year, which is more than twice the annual mercury emissions of the United States, and is one of the main sources of mercury pollution in the world (see Figure 1 and Figure 2) . Faced with increasingly severe international negotiation pressure, the Ministry of Environmental Protection of China promulgated GB13223-2011 "Emission Standards of Air Pollutants for Thermal Power Plants" for the first time in July 2011, including mercury as a new control indicator, requiring new power plants after 2012 The mercury emission limit is 0.03mg/m3. From January 1, 2015, all coal-fired units in operation must meet this mercury emission standard. So far, my country's first coal-fired mercury pollution control standard has been issued.

Utility model content

The purpose of the utility model is to overcome the deficiencies of the prior art, and provide a variety of flue gas purification synergistic mercury removal devices and methods with reasonable structure, good purification effect, good equipment compatibility and operation safety.

Such a variety of flue gas purification and mercury removal devices include clean coal devices, boilers, SCR denitrification devices, dust collectors and FGD desulfurization devices. The outlet of the clean coal devices is connected to the feed port of the boiler, and the smoke The crossing is connected to the input port of the SCR denitration device, the output port of the SCR denitrification device is connected to the dry dust collector, and the output of the dry dust collector is to the FGD desulfurization device.

The SCR denitrification device includes a sequentially connected injection active adsorbent device and a denitrification catalyst device.

The FGD desulfurization device includes an oxidant adding device, a spray washing device and a wet electrostatic precipitator connected in sequence.

The beneficial effects of the utility model are:

1) Organic integration of technologies to gradually and synergistically remove mercury

The synergistic mercury removal technology of various flue gas purification devices organically integrates a variety of advanced mercury removal technologies. The rational arrangement of various technologies and equipment in this collaborative mercury removal technology also makes the mercury removal efficiency of this collaborative mercury removal technology reach a new height, enabling power plants to meet the latest national mercury emission standard of 0.03 mg when burning high-mercury coal /m ³ .

2) Good equipment compatibility and operation safety

A variety of flue gas purification devices cooperate with mercury removal technology to integrate multiple devices. Through device integration, the compatibility and matching degree between devices can be improved. The addition of other devices can improve the mercury removal efficiency of a single device (such as modified catalysts and The oxidant oxidizes the zero-valent mercury into divalent mercury, which is then removed by the downstream wet desulfurization unit) to achieve a synergistic mercury removal effect.

3) Good adaptability

The collaborative mercury removal technology of various flue gas purification devices can be applied to various coal-fired units, and can be adjusted according to the conditions and requirements of the units to achieve the best results.

Description of drawings

Fig. 1 is a device diagram of the present utility model;

Fig. 2 is a working principle diagram of the utility model;

detailed description

Below in conjunction with accompanying drawing and embodiment the utility model is described further. Although the utility model will be described in conjunction with preferred embodiments, it should be understood that it does not mean that the utility model is limited to the embodiments. On the contrary, the invention is to cover alternatives, modifications and equivalents, which may be included within the scope of the invention as defined by the appended claims.

As shown in Figures 1 to 2, this multiple flue gas purification and mercury removal device includes a clean coal device, a boiler, an SCR denitrification device, a dust collector, and a FGD desulfurization device. The outlet of the clean coal device is connected to The feed port of the boiler and the flue port of the boiler are connected to the input port of the SCR denitration device, the output port of the SCR denitrification device is connected to the dry dust collector, and the output of the dry dust collector is to the FGD desulfurization device.

The SCR denitrification device includes a sequentially connected injection active adsorbent device and a denitrification catalyst device.

The FGD desulfurization device includes an oxidant adding device, a spray washing device and a wet electrostatic precipitator connected in sequence.

The method of multiple flue gas purification in conjunction with a mercury removal device comprises the following steps:

Step 1, using foam flotation method to wash coal, and then adopting mild pyrolysis method to evaporate mercury by heating;

Step 2, coal enters the boiler for combustion;

Step 3. The flue gas produced by the coal combustion of the boiler enters the SCR destocking device, and the active adsorbent is sprayed into the flue behind the air preheater, which continuously absorbs mercury in the flue gas to form mercury particles; the active adsorbent is fly ash or Activated carbon, etc. The adsorption of mercury by fly ash is mainly through physical adsorption, chemical adsorption, chemical reaction and the combination of the three. The higher the carbon content of the fly ash, the more favorable the adsorption of mercury.

Step 4. Through the denitration catalyst in the SCR denitrification device, the zero-valent mercury is transformed into water-soluble divalent mercury and particulate mercury, and then the divalent mercury is removed in the subsequent wet desulfurization device;

Step 5: The flue gas from the SCR removal device enters the dry dust collector to remove the contained mercury particles;

Step 6. The flue gas from the dry precipitator enters the FDG desulfurization device, and the zero-valent mercury is converted into divalent mercury through the addition of front-end oxidant, and then the divalent mercury is removed by spray washing, and then passed through the wet electrostatic precipitator Carry out dust removal to remove particulate mercury.

Utilize the existing coal washing, desulfurization and denitrification devices of coal-fired power plants, through the application of clean coal technology, active adsorption medium injection technology, catalyst modification technology, oxidant addition technology and wet electrostatic precipitator technology, the particulate mercury and bivalent Mercury is effectively removed. Zero-valent mercury is extremely difficult to be removed by existing pollutant removal devices. The focus of this technology is to convert zero-valent mercury into particulate mercury and divalent mercury, and then remove them, so as to realize the coordinated removal of mercury (details See Figure 1, Figure 2).

1. Clean coal technology

Using foam flotation method for coal washing can reduce the mercury content of coal by more than 30%, and then adopt mild pyrolysis method to evaporate mercury by heating, further reducing the mercury content in coal, and the removal efficiency can reach more than 80%. With the help of these two clean coal technologies, the mercury content of the coal can be reduced by 85% before it enters the boiler for combustion.

2. Active adsorption medium injection technology

Mercury in flue gas can be removed by the adsorption of active agents such as fly ash and activated carbon. The adsorption of mercury by fly ash is mainly through physical adsorption, chemical adsorption, chemical reaction and the combination of the three. The higher the carbon content of the fly ash, the more favorable the adsorption of mercury. In this method, the active adsorbent is injected into the flue after the air preheater, which continuously adsorbs the mercury in the flue gas, and then is removed by the dry dust collector behind it.

3. Oxidant addition technology

The oxidant addition technology is to spray the halide solution on the coal in front of the furnace or spray it directly into the furnace. Increasing the content of chlorine or bromine in the coal can increase the conversion rate of elemental mercury to water-soluble divalent mercury in the flue gas. Finally, it is captured by the wet desulfurization device to achieve the purpose of mercury removal.

4. Modified catalyst technology

The catalyst in the SCR denitrification device is modified so that it can not only have the function of a normal denitrification catalyst, but also improve its ability to oxidize zero-valent mercury, improve the conversion rate of zero-valent mercury to water-soluble divalent mercury, and then in the subsequent wet The divalent mercury is removed in the desulfurization device.

5. Wet desulfurization and mercury removal technology

Through the oxidation of zero-valent mercury by the front-end oxidant addition technology and modified catalyst, most of the zero-valent mercury is converted into divalent mercury, and then most of the mercury oxide in the flue gas is removed in the wet desulfurization device, and the removal efficiency can be improved. Up to 80% or more.

Through the full integration and mutual synergy of the above five technologies, the mercury content in the flue gas that is finally discharged into the atmosphere can be far lower than the national standard of 0.03mg/m ³ , reaching the emission requirement of ≤5μg/Nm ³ .

The collaborative mercury removal technology of various flue gas purification devices has been applied to the 1×1000MW unit of Jiaxing Power Plant, which is a renovation project. The mercury emission value of flue gas at the total outlet is 1.99μg/Nm ³ , which is far lower than the national standard.

Claims (3)

1. mercury removal device is worked in coordination with in one kind of multiple gas cleanings, it is characterized in that: comprise Filter Tuber For Clean Coal device, boiler, SCR denitration device, deduster and FGD desulfurizer, the discharging opening of described Filter Tuber For Clean Coal device is connected to the charging aperture of boiler, the floss hole of boiler is connected to the input port of SCR denitration device, the delivery outlet of SCR denitration device is connected to dry collector, and dry collector exports FGD desulfurizer to.

2. mercury removal device is worked in coordination with in multiple gas cleaning according to claim 1, it is characterized in that: described SCR denitration device comprise connect successively spray into hypersober device and denitrating catalyst device.

3. mercury removal device is worked in coordination with in multiple gas cleaning according to claim 2, it is characterized in that: described FGD desulfurizer comprises the oxidant adding set, spray washing device and the wet electrical dust precipitator that connect successively.