MX2008005998A - Functional fluid and a process for the preparation of the functional fluid - Google Patents

Abstract

A new functional fluid for the removal of contaminates such as but not limited to, acid causing components in gas, sulphur components and carbon oxides from fluid streams, and removal and treatment of NOX&SOXfrom post combustion emissions. Also described is the manufacturing process to produce the functional fluid both in a batch atmospheric process system as well as a closed system capable of operating at above or below atmospheric conditions.

Description

FUNCTIONAL FLUID AND A PROCEDURE FOR THE PREPARATION OF FUNCTIONAL FLUID TECHNICAL FIELD The present invention relates to a functional fluid and particularly to a functional fluid for use in, for example, the treatment and removal of acids, acidulated components (for example H2S) and gases C02, CO, NO? and SOx of fluid streams (for example a fluid stream based on hydrocarbons) or fuels or post-combustion gases. The invention also relates to a process for the preparation of the functional fluid.

BACKGROUND OF THE INVENTION In the extraction, processing and refining, storage and combustion of compositions based on hydrocarbons and carbon (for example crude oil, synthetic crude, natural gas, coal and coke) are found and / or produce significant amounts of toxic substances. These substances include, for example, hydrogen sulfide gas, mercaptans, SOx gases (for example S02 and S03) and NOx gases (for example NO, N02 and N20). Hydrogen sulfide and mercaptans are often extracted with crude oil. Carbon dioxide, carbon monoxide and SOx gases can be produced during processing and refining of crude oil. NO gases? they can be produced with the combustion of hydrocarbon-based fuels. Moreover, post-combustion fumes from coal-fired power stations, coking plants, and steel production plants generally contain one or more of these gases. Therefore there is a continuous need for the development of compositions and procedures that allow the removal of these gases from hydrocarbon-based streams, chimneys and leaks. The H2S-exclusive compounds typically comprise amine adducts and methods of preparing them often require the use of complex reaction protocols and toxic reaction materials to the environment. For example, GB 2409859 discloses a petroleum-soluble sulfur excluder that includes substantially monomeric aldehyde-amine adducts from the reaction of at least one sterically hindered primary or secondary amine and a molar excess of at least one aldehyde, or a donor of the same. U.S. Patent Application No. 2005/0214199 discloses a high surface area manganese oxide compound used to remove contaminants such as NO ?, SO ?, and CO by adsorption and oxidation. The manganese oxide is prepared by the reaction of a bivalent manganese salt with solutions of permanganate and alkali metal hydroxide in the presence of ion exchange water under specific reaction conditions. Reported removal rates of up to 35% are reported with respect to carbon monoxide.

Then, there is a need for additional compositions for use in the removal of toxic substances. There is also a need for compositions that can be prepared through relatively direct and inexpensive reaction protocols. There is also a need for the preparation and isolation of compositions having multifunctional use in a number of applications, such as those described above.

BRIEF DESCRIPTION OF THE INVENTION According to a first aspect of the present invention there is provided a process for the preparation of a functional fluid comprising reacting silicon, alkali metal hydroxide and a solution comprising water and chlorine in a reaction vessel at a temperature no greater than approximately 93 ° C (200 ° F). The optional features of the first aspect of the invention are the subject matter of the dependent claims. Then, the process provides for the preparation and isolation of a new functional fluid through an economical and relatively direct process. It has been found that the functional fluid has utility in a number of applications as an electron donor, reducing agent or antioxidant. Advantageously, the process provides an exclusive functional fluid without the need to include chemical compounds costly organics that can result in the formation of reaction byproducts. Such by-products can be difficult and expensive to eliminate, due to environmental conditions. An additional advantage is that the functional fluid can be prepared under atmospheric or pressurized conditions. According to a second aspect of the invention there is provided a functional fluid having a specific gravity of about 1.25 to 5, and a pH of about 9 to about 13, which is obtained by the method of the first aspect of the invention. Another advantage of the invention lies in the preparation and isolation of a functional fluid, which has a multifunctional use. For example, the functional fluid can be used in the oil and gas production industry as an exclusion of H2S in crude oil pumping pipes as a corrosion inhibitor in pipelines. Furthermore, the fluid can be used in the treatment of C02 and N02 that are produced during the refining of crude oil, and / or with the combustion of the crude product. The functional fluid of the second aspect of the invention can be used as an excluder of CO, C02 or H2S. The functional fluid can be used as an exponent of H2S in wet oil and gas production systems. The functional fluid can be used in the treatment of NOx (for example NO and N02) and SOx gases (for example S02 and SO3).

The functional fluid can be used in acidified gas treatment systems. The functional fluid can be used as a corrosion inhibitor. The functional fluid can be used as a carbon steel pacifier to reduce the corrosion rates associated with acid gases. The functional fluid can be used as an antifoaming agent. The functional fluid can be used in the removal of residual water contaminants or boiler feed water. The functional fluid can be used as a storage for hydrogen gas. According to a third aspect of the invention, there is provided a process for the desulfurization of a stored hydrocarbon gas feed comprising: (i) contacting the stored hydrocarbon gas feed with a functional fluid as specified in the first and second embodiments under suitable conditions to form a functional fluid enriched in sulfur; and (ii) recovering a stored feed of desulphurized gaseous hydrocarbon from the functional fluid enriched in sulfur. The method of the third aspect of the invention may optionally comprise, the steps of: (iii) contacting the sulfur-enriched functional fluid with a flocculating agent under conditions sufficient to allow precipitation of the sulfur from the functional fluid enriched in sulfur; and (v) separating the precipitated sulfur from the fluid to recover a functional fluid as specified in the first or second aspects of the invention. According to a fourth aspect of the invention, a method is provided for the removal of C02 from the stored hydrocarbon gas feed, which has a C02 component, comprising the steps of: (i) contacting the functional fluid and the stored hydrocarbon gas feed under conditions sufficient to dissolve C02 in the functional fluid; (ii) separating the stored feed of gaseous hydrocarbon from the functional fluid; and (iii) depressurizing the functional fluid to cause evolution of the C02 gas of the functional fluid.

BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of the present invention, and to demonstrate more clearly how it can be carried out, reference will now be made, by way of example, to the following drawings, in which: Figure 1 is a schematic representation of an atmospheric process for the manufacture of the functional fluid of the invention; Figure 2 is a schematic representation of a closed pressure system above or below atmospheric for the manufacture of the functional fluid of the invention; Figure 3 is a schematic representation of a process for the removal of H2S from a methane gas feed; Figure 4 is a schematic representation of an example of a desulphurisation process applied to an existing desulfurization process as a retrofit; and Figure 5 is a schematic representation of a process for the removal of C02 from a methane gas feed.

DETAILED DESCRIPTION OF THE INVENTION The functional fluid is formed by the reaction of an alkali metal or a derivative thereof with silicon. First, the reagents used in the reaction process will be described.

Silicon The silicon used in the process of the invention can be elemental silicon, or metallic silicon. The metallic silicon exists in a number of degrees of purity. Examples of silicon metal that can be used in the process are grade 551 metallic silicon (98.5% Si, 0.5% maximum Fe content, 0.10% maximum Ca content), 553 grade silicon metal (98.5% Si, 0.5% maximum Fe content, 0.30% maximum Ca content), silicon metal grade 441 (99% Si, 0.5% maximum Fe content, 0.10% maximum Ca content), silicon metal grade 442 (99% Yes, 0.4% maximum content of Fe, 0.20% maximum content of Ca), silicon metal grade 4406 (99.3% Si, 0.4% maximum content of Fe, 0.06% maximum content of Ca), silicon metal grade 4403 (98.5% Si, 0.4% maximum Fe content, 0.03% maximum Ca content), 331 grade metallic silicon (99.3% Si, 0.3% maximum Fe content, 0.10% maximum Ca content), grade 3305 metallic silicon (99.4% Si, 0.3% maximum Fe content, 0.05% maximum Ca content), grade 3303 metallic silicon (99.4% Si, 0.3% m Maximum Fe content, 0.03% maximum Ca content), 2204 grade silicon metal (99.5% Si, 0.2% maximum Fe content, 0.04% maximum Ca content), 2202 grade silicon metal (99.5% Yes, 0.2% maximum content of Fe, 0.02% maximum content of Ca) or silicon metal grade 1501 (99.5% Si, 0.15% maximum Fe content, 0.01% maximum Ca content). The grade 441 metallic silicon is the preferred grade of metallic silicon used in the process for preparing the functional fluid of the invention.

The silicon or metallic silicon can comprise a scale of particle sizes. These particles may be in the form of coarse pieces or ingots (for example having an average diameter of up to about 150 mm), or in the form of powder. In one embodiment, the silicon or metallic silicon comprises particles with a mean particle diameter of between about 1 mm and about 150 mm. In another embodiment, the silicon or the metallic silicon comprises particles with a mean particle diameter of between about 24 mm and 150 mm. In a further embodiment, the average particle diameter is greater than about 10 μm, such as greater than 100 μm, for example greater than 500 μm. the average particle diameter can also be less than 10 mm, for example less than 5 mm, such as less than 2 mm or less than 1 mm. Where the particles are not spherical, the term "diameter" refers to the largest dimension of the particle. Some individual particles may have an outside diameter of the specified values. However, preferably at least 50%, for example at least 95%, such as 99% of the particles have a diameter within the specified values. In one embodiment, substantially all particles have a diameter within the specified scale.

Alkali metal hydroxide The alkali metal hydroxide used in the process may comprise lithium hydroxide, sodium hydroxide or potassium hydroxide. In one embodiment sodium hydroxide is used. Combinations of lithium hydroxide, sodium hydroxide and potassium hydroxide can also be used in the process. The alkali metal hydroxide (for example sodium hydroxide) can be used in solid form or in the form of an aqueous solution prepared from the alkali metal hydroxide. In the solid form the alkali metal hydroxide may be in the form of flakes, beads or powder. Alternatively, the alkali metal hydroxide can be replaced by another alkaline and alkaline earth metal hydroxide such as rubidium hydroxide, beryllium hydroxide, magnesium hydroxide, calcium hydroxide, strontium hydroxide or barium hydroxide.

Water and chlorine solution The water and chlorine solution used in the process comprises water, preferably distilled water, and a source of chlorine. The source of chlorine can be chlorine gas which then dissolves in water. In a preferred embodiment, the source of chlorine is liquid chlorine, also known as sodium hypochlorite (NaOCI). Water (preferably distilled) and liquid chlorine are combined in a ratio of about 10: 1 to about 30: 1 in volume (water: liquid chlorine), for example between about 15: 1 and about 25: 1. In one embodiment, the ratio of water to chlorine is approximately 20: 1. The water and the liquid chlorine can be combined before the addition to the reaction vessel comprising the silicon and the alkali metal hydroxide, or the water and the chlorine can be added separately, in situ.

The procedure and the resulting functional fluid As discussed above, the duration of the process of the first aspect of the invention will depend on factors such as reaction temperature and reagent particle size (due to the effect of particle size on the considerations of the area). superficial). The duration of the reaction will be shorter when using small particles and longer when large particles are used. In most embodiments, the duration of the reaction will be greater than about one hour, for example longer than about 3 hours such as longer than about 6 hours. The duration of the reaction may also be less than about 3 days for example less than about 2 days such as less than about 1 day or less than about 12 hours. Because the reaction is exothermic, the particle size control of the reagent provides a means to control to some degree the speed of the reaction and then the degree to which it requires cooling the reaction vessel during the process of the first aspect. The reaction vessel is maintained at a temperature below about 93 ° C. Subject to this condition, in some embodiments, the reaction temperature may be maintained at a temperature greater than about 60 ° C, for example greater than about 70 ° C. In one embodiment, the reaction temperature is maintained at a value of about 80 ° C. The following analysis is limited to a process comprising grade 441 metal silicon and sodium hydroxide, by way of example. Also included are references to Figures 1 and 2 of the invention to aid in the understanding of the method of the invention. However, these are non-limiting, and the skilled person will be aware that the following analysis will be typical for a number of alternative systems as described above. Typically, grade 441 metal silicon and alkali metal hydroxide are combined in a reaction vessel. Figure 1 shows an atmospheric batch process for the manufacture of the functional fluid of the invention. An open reactor 1, preferably made of stainless steel, is charged with silicon (metal grade silicon 441) 2 of a particle distribution in the range of 24 mm to 150 mm in average diameter. The silicon 2 is charged at a height equivalent to 30% of the reactor volume including the voids of the silicon particles 2. Sodium hydroxide 3 (flake form) is added to the silicon 2 in reactor 1 at a level approximately equivalent to the gaps available in the silicon 2, so that the level of the solids in the reactor substantially does not change. This is effected by perfectly mixing the silicon 2 and the sodium hydroxide 3. The amount of silicon to sodium hydroxide is approximately typically 1: 1 by volume. It will be clear to the skilled person that the size of the silicon particles used will affect the reaction rate (i.e. with the addition of the water-chlorine solution) depending on the surface area of the silicon particles. Distilled water 4 is dosed with liquid chlorine 5, for example in a water to liquid chlorine ratio of approximately 20: 1 by volume, before introducing the same to reactor 1, and initiating the reaction between the components. The water-chlorine solution is added at one level (level 6 in Figure 1) at least equal to or greater than the level of the silicon / sodium hydroxide mixture, so that the silicon / sodium hydroxide is completely submerged in the water-chlorine solution. Typically, there will be a period of time before any appreciable reaction occurs. This space of time will depend on the amount of reagents used (ie the ratio of the volume of silicon to sodium hydroxide), and the particle size of silicon 2 and sodium hydroxide 3. The resulting exothermic reaction begins to efferve with the release of hydrogen gas 7 and steam 8. Therefore, adequate safety measures must be employed. The reaction temperature is maintained so that it does not exceed approximately 93 ° C (200 ° F), and is maintained preferably below about 80 ° C (175 ° F). The temperature of the reaction is maintained using external heating / cooling means 10, for example, by the use of a heating / cooling jacket. Additional water and / or water-chlorine solution is added as the reaction proceeds to maintain the level of the solution above the silicon / sodium hydroxide (ie to equal the losses that are attributed to the loss of hydrogen gas and steam). Under the conditions described above, typically the reaction takes up to six hours, after which the degree of effervescence begins to decrease, and the resulting functional fluid is ready to decant through outlet 9 through a suitable filtration medium for remove any unwanted particles, which can continue reacting. The finished chemical is then stored in sealed drums ready for use. Figure 2 shows an example of a closed or pressurized system apparatus, which can be operated above or below atmospheric pressure. A hopper 33 is loaded with the same quantities and qualities as described for Fig. 1, silicon 21 and sodium hydroxide 20, for a given lot size. However, it has been found in practice that in a closed system, such as the one shown in Fig. 2, silicon can be used of a considerably smaller particle size distribution as low as 1 mm, thus enabling the area surface of silicon available for the contact to increase substantially. This, together with the ability to control the pressure inside the container by pressure control means 29 allows the reaction to be more controlled, and then reduces the required reaction time of the silicon to produce the required chemical. The silicon 21 and the sodium hydroxide 20 are fed from the hopper 33, controlled by valve means 28, into the pressure reaction vessel 27. The valve means 28 is then closed, and a pump 24 is started, which is fed with a mixture of water 23 and chlorine 22. The mixture is reported through the valve means 25 to a vortex generator 31, located inside the pressure vessel 27. Then the reaction starts and is subsequently accelerated by the constant intermixing of the particles 20 and 21 and the liquid 22 and 23, by the centrifugal forces inside the vortex. The hydrogen gas and vapor generated by this reaction are collected in the upper portion of the pressure vessel 27, and the pressure inside the pressure vessel 27 is controlled to the set point required by a pressure sensor, controller and a valve. pressure control 29. The gases removed from the pressure vessel 27 can be routed to a flame recuperator 30, and / or a scrubber / condenser 37, which in turn, if required, can reroute the hydrogen back into the pressurized reactor 27 without the associated water vapor caused by the reaction. Hydrogen can then be reabsorbed to further enrich the chemical, or if not required, it can be stored or carried to a waste torch. It is an additional requirement of the procedure, that the level of liquid in the pressure reactor 27 remain within the limits of the required level. Therefore the level indicator 26 has the ability to operate the pump 24 and to operate the valve means 25 to add spare water as required. When the pump 24 is not in operation and it is required to maintain the vortex inside the pressure reactor 27, then a pump 40 is started and the chemical is recirculated through the vortex generator 31 as required to maintain the solids 20 and 21 in suspension. A cooling jacket 41 can be fed with a cooling means to regulate the temperature of the process within the required limits by interacting with the temperature controller 32. If requiredVacuum can be used at the steam outlet 29, which in some conditions will increase the production of the chemical. When the chemical reaction is finished, the pump 40 is stopped and the valve means 39 are closed. The valve means 34 is opened and the chemical is reported to the filter 35, and in the storage container 36. The function of the chlorine The liquid in the reaction is not completely understood, but without wishing to be bound by any theory it is believed that chlorine acts as an electron collector of the reaction. If liquid chlorine is not used, then sodium silicate salts will be formed instead of the functional fluid. If an aqueous sodium hydroxide solution is used, then the space of time will be much shorter due to the presence of water liquid before the addition of the water-chlorine solution. Under these circumstances, liquid chlorine should be added before effervescence to minimize silicate formation. The functional fluid prepared by the reaction described above is typically a clear, transparent, viscous liquid having a specific gravity of about 1.25 to 5, for example about 5, and a pH on the scale of about 9 to about 13, for example of approximately 9 to approximately 12. However, the functional fluid may sometimes appear translucent. The functional fluid can be used as prepared, or it can be used in a diluted form; for example, the functional fluid can be diluted to a specific gravity of about 1.25 before use.

Characterization of the functional fluid of the invention The precise composition and the form of the functional fluid are not completely understood, but it is believed that silicon and alkali metal ions form a monomeric inorganic complex soluble in water with the chlorine water solution. It is not clear if chlorine, probably present as chlorine ions, is part of the inorganic complex. It is found that the resulting functional fluid comprising the silicon-alkali metal complex is rich in electrons (possibly comprising free electrons), and acts rapidly as a reducing agent in the presence of other chemicals with the conversion of these chemicals to salts soluble in water, or even elemental compounds. For example, with the reaction between the functional fluid and H2S, elemental sulfur can be formed. Then, the functional fluid of the present invention has the ability to selectively remove target contaminants from any fluid, carbon-based stream.

Utility of the functional fluids of the present invention The functional fluid of the invention has utility in a number of applications, for example: • As an exclusion of C02 • As an exclusion of H2S • In the treatment of NO gases? (for example NO and N02) & of SO? (for example S02 and S03) • As a corrosion inhibitor • In the increase of acidified gas treatment systems such as amine plants • In the removal of contaminants from water eg pre-treatment of boiler feed water and treatment wastewater by Volatile Organic Compounds (VOC) and Tertiary Methyl Butyl Ether (MTBE) and The destruction of many forms of bacteria such as feta coli, cryptosporidium and legionnaires • Rejection of hydrocarbons from solids wetted with oil, for example, in the solid rock formations through which oil is formed, the functional fluid moisturizes the production zone and is attracted to the formation of rocks, thus forcing oil out of the rock, reducing drag and improving oil flow • In the removal of all types of sulfur-containing substances, in particular carbonyl sulfide (COS- for its acronym in English) is known to be hydrolyzed with water to form H2S , S and C02. • As an antifoaming agent • As a flame retardant • As an antioxidant corrosion inhibitor, for example, when the chemical is injected into a pipe or container made of carbon steel, it has the ability to protect the pipe or container from corrosion • As a medicine or in the manufacture of a medicine, for example, for the treatment of an insect bite, a viral and / or blood condition.

Process for the desulfurization of stored hydrocarbon gas feed In a third aspect of the invention, the stored hydrocarbon gas feed (which can be, for example, natural methane gas) can be contacted with the functional fluid of the invention using any device suitable known in the art for that purpose. For example, an in-line mixer / contactor or a countercurrent flow separation tower can be used. In contrast to the prior art desulfurization units such as amine systems, the process of the third aspect does not require boilers, heaters, acid separators or reinjection processing units. The process of the third aspect can therefore be carried out at room temperature, for example greater than about 5 ° C, such as greater than 10 ° C or greater than about 15 ° C. The process temperature may be less than about 60 ° C, for example less than about 40 ° C, such as less than 30 ° C. This method is therefore particularly useful in, for example, for pre-treating natural methane gas prior to processing, offshore Liquefied Natural Gas (LNG) plants, where the close proximity of heat sources to units Cryogenic and cooling boxes can present a dangerous operation. The method of the third aspect of the invention can further optionally comprise the steps of: (n) contacting the sulfur-enriched functional fluid with a flocculating agent under conditions sufficient to allow precipitation of the sulfur from the functional fluid enriched in sulfur; and (iv) separating the precipitated sulfur from the fluid to recover functional fluid from the first or second aspects of the invention. The flocculating agent can be any known flocculating agent capable of inducing the precipitation of sulfur in the alkaline environment of the functional fluid. For example, the flocculating agent can be an alkali metal halide, preferably sodium chloride. The precipitated sulfur can be separated by any suitable separation process. For example, a plate filter press can be used. It has been found that the use of a plate filter press gives a reasonably dry solid suitable to avoid disposal from the site. The tests to date have shown that the solids generated by this procedure are suitable for sanitary landfills and result in minimal impact to the environment. It has been found that the method according to the third aspect of the invention is capable of reducing the level of hydrogen sulfide in the natural methane gas from a level in the region of 10,000 ppm to a level of less than 1 ppm. The method may further comprise the step of recycling the functional fluid recovered for use in step (i) of the third aspect of the invention.

Before recycling, the pH of the recovered functional fluid can be modified to be greater than about 12, for example at a pH of about 13. This can be done by adding an alkali metal hydroxide, for example sodium hydroxide. The stored gaseous hydrocarbon feed may be any stored gaseous hydrocarbon feed but more typically it will be a stored feed comprising predominantly methane such as natural gas. The third aspect of the invention will now be illustrated with reference to a process for the removal of H2S from a stored methane feed. References to Figures 3 and 4 of the drawings are also included to aid in the understanding of the method of the invention. However, these are not limiting, and the experts will be aware that the following analysis will be typical for a number of alternative systems as described above. Fig 3 shows a three-phase process exemplifying the third aspect of the invention. The gas to be treated is fed to the contactor of phase one in which the functional fluid (designated MonoChem) and the acidulated gas are brought into contact with each other. The functional fluid is separated from H2S and rejects methane gas. The gas sweetened within specification then exits the contactor of phase one and goes directly to any of a tertiary polishing system or, if the gas condition is acceptable, to a gas export pipe for its use. The functional fluid enriched with H2S from the contactor of phase one is then directed, under level control in the case of a contact tower, to phase two, to a smaller secondary mixer / contactor, with sufficient residence time to act as a development tank. The flocculator is added to the MonoChem stream at the entrance of this tank to allow the sulfur to flocculate and develop as a solid. The mixture of liquid and solids from phase two is then directed to phase three, which can be any form of filtration or clarification of liquids / solids. In practice, a plate filter press has been shown to be suitable for this purpose, giving a reasonably dry solid adequate to avoid disposal from the site. The tests to date have shown that the solids generated by this procedure are suitable for sanitary landfills with minimal impacts to the environment. The liquid filtrate from phase three is recycled to phase one, for reuse in the procedure. Depending on the pH of the recycled functional fluid and its specific gravity, a pH-correcting chemical may be added to maintain the pH of the functional fluid at about 13. In Fig 3 the functional fluid of the invention is recirculated in the system at a rate of flow determined by the amount of H2S that is going to be removed from the gas stream. In one example 37.85 liters per minute (10 US gallons per minute) (it was enough to remove up to 10,000 ppm of H2O of 19,822 cubic meters per day (700,000 standard cubic feet per day) (SCFD) of natural gas. The aforementioned procedure has also proven to be useful for the removal of C02. It can be shown that C02 can evaporate instantaneously to a gas phase again once the MonoChem pressure drops. To date, C02 levels of up to 10,000 ppm together with 10,000 ppm of H2S in a methane gas stream have been removed simultaneously.

The application of retro-adjustment of the procedure of the third aspect In practice, existing gas treatment processing plants, such as the Amina and Claus units, can be a bottleneck in systems where the entry conditions have been changed by any reason, for example: • The gas volume is increased • Pressure drops • The volume of H2S is increased • Variations in the inlet temperature Changes of this type, in the entrance of the Amina systems can alter the operation and require changes in the system, which in most cases adjust and cause chain reactions in the operation of the plant leading to major alterations.

Due to the simplicity of the functional fluid system of the MonoChem it is now possible to offer a process phase to apply upstream of existing gas sweetening plants to effectively eliminate the process bottleneck, or to substantially reduce the cost of maintenance where existing systems are of the absorption type, which requires spending material to be removed and replaced. Fig. 4 shows said system. In Fig. 4, a compact functional fluid contactor system is placed in front of an existing gas treatment plant. The compact functional fluid contactor may optionally be derived or used to treat a proportion of the total gas flow to be treated. The proportion of treated gas can be sufficiently large that when re-combined with the untreated gas, the resultant H2S ppm left in the system is manageable by the existing gas treatment plants. In Figure 4, numerous online mixers / contactors are used in series with each unit having the MonoChem injected therein. Each unit is capable of removing up to 50% of the H2S by volume at the gas inlet as described in Table 1 below. This is an example that illustrates the procedure. The removal efficiency of each phase depends on factors such as the condition of the functional fluid in each phase and the levels of contaminants present in the feed in the phase: TABLE 1 Generally, it can be said that the more units used, the better the removal of H2S, although there will be a point at which the benefit gained from each extra unit is minimal. The retrofit system is normally designed to effect a total removal level of up to 95% leaving the final H2S to be removed in the existing equipment. This retrofit system offers numerous advantages to operators of the process plant, such as: - By using recovery in progress within the inlet pipe of existing plants, the modifications do not necessarily require causing a plant shutdown. - If required the existing Amina tower can be quickly converted to a system that uses MonoChem with the MonoChem reporting to the development tank and filtering units used to recover the MonoChem from the In this aspect of the invention, the stored hydrocarbon gas feed (which can be, for example, natural methane gas) can be contacted with the functional fluid of the invention using any suitable apparatus known in the art for that purpose. For example, an in-line mixer / contactor or a countercurrent flow separation tower can be used. The pressure at which the functional fluid and the stored gaseous hydrocarbon feed are brought into contact will depend on the required degree of removal of C02 from the stored feed. Under conditions of higher pressure, more C02 will dissolve in the functional fluid. Typically, the system pressure will be greater than 1 kg / cm2, for example greater than 5.16 kg / cm2 such as greater than 10.33 kg / cm2. The pressure can also typically be less than 30.99 kg / cm2, for example less than 20.66 kg / cm2. In an alternative embodiment, the functional fluid and stored hydrocarbon gas feed may be contacted under ambient conditions or at a below ambient pressure, with the proviso that, following step (ii) above (the separation of the feed stored gaseous hydrocarbon functional fluid), the pressure is further lowered to cause the evolution of C02 functional fluid. It is believed that the solubility of C02 in the functional fluid is inversely proportional to the temperature of the fluid. Therefore, for contactors of the pipes. In this way, the units downstream of the Amina plants become redundentes, this substantially reduces the emissions from the site. - No liquid acid is formed so there is no need to remove a liquid acid from the site. - The possibility of converting to solids is suffered in fertilizer, for commercial use.

Selective removal of stored hydrocarbon gas feed CQ2 comprising CO? Components and sulfur According to a fourth aspect of the invention, a method is provided for the removal of CO2 from a stored hydrocarbon gas feed, which has a C02 component, comprising the steps of: (i) contacting the fuid functional and the stored hydrocarbon gas feed under conditions sufficient to dissolve C02 in the functional fluid; (ii) separating the stored feed of the gaseous hydrocarbon from the functional fluid; and (iii) depressurizing the functional fluid to cause evolution of the C02 gas of the functional fluid.

To increase the solubility of C02 in the functional fluid, the functional fluid should be provided at a reduced temperature. The fluid can in principle be provided at any temperature above its freezing point, with the highest solubility of C02 exhibiting at the lowest temperatures. However, there is an economic consideration associated with the cooling of the functional fluid and thus in some embodiments, the fluid will be provided at high temperatures. In some embodiments, the fluid is provided at a temperature below about 50 ° C, for example below about 40 ° C or below about 30 ° C. The fluid can also be provided at a temperature below about 20 ° C for example below about 10 ° C. In a preferred embodiment, the fluid is provided at a temperature below 5 ° C, such as on the scale of about 1-3 ° C, for example about 2 ° C. The process may further comprise the step of liquefying the separate CO 2 gas obtained in step (iii) of the process. This procedure is therefore advantageous in that it allows the collection of C02 for commercial applications, while preventing it from escaping into the environment. The liquefied C02 has a very advanced market in the following areas: (a) Fraccionamiento at the bottom of the well (fracc de C02) (b) Formation of flood of Recovery of Secondary or Increased Oil (EOR- for its acronym in English). (c) Treatment of PLM (for its acronym in English) or NGL (for its acronym in English) for standard gas (d) Many other commercial and industrial uses of C02. In an alternative mode, which is currently the least preferred, following the dissolution of C02 in the functional fluid it is possible to break the bond between the C02 and the functional fluid and filter the carbon content as a solid, typically as sodium bicarbonate, with the O2 being released into the system. In this embodiment, the functional fluid is sacrificed as an excluder and this results in the depletion of the functional fluid. In an embodiment of the fourth aspect of the invention, the hydrocarbon feed comprises sulfur-containing compounds (such as H2S) in addition to the specified CO 2 component. It was surprisingly found that by providing the functional fluid at a reduced temperature, it is possible to selectively separate C02 from the stored hydrocarbon feed, without removing the H2S component. In this embodiment of the invention, the functional fluid can be provided at a temperature below about 5 ° C, preferably in the range of about 1-3 ° C, for example at a temperature of about 2 ° C. The process may also comprise the removal of the sulfur compounds from the separated gaseous stored feed using the method of the third aspect of the invention.

The fourth aspect of the invention will now be illustrated with reference to a process for the removal of C02 from a stored methane feed containing C02 and H2S. The reference to Figure 5 of the drawings is included to aid in the understanding of the method of the invention. However, reference to this figure is not limiting, and the skilled person will be aware that the following analysis will be typical for a number of alternative systems as described above. Fig. 5 below shows a typical system for use when C02 and H2S coexist in a methane gas stream and C02 is required to be selectively removed from the gas stream. For the removal of C02 from the natural methane gas stream, the pressurized methane gas and associated C02 are directed into the contactor T101 where a stream of the functional fluid of the invention (M), at a temperature of about 1 to 2 ° C. , it is distributed above a typically random packing inside the countercurrent separation tower. The gas contacts the functional fluid, where the CO2 associated with the gas is preferably dissolved in the functional fluid. The functional fluid rejects the methane gas that then exits the contactor. A level control valve (L) allows the functional fluid with the C02 in solution to exit the contactor where it is directed to the extraction vessel of C02 T102, through an array of spray nozzles. A pressure drop in the container T102 together with the agitation caused by the spray nozzles drives the C02 out of the solution. The C02 leaves the top of the T102 through a spray eliminator. Depending on the procedure and regulations of the local environment, C02 can then be burned or liquefied for use in flood or used in other applications. The C02 free functional fluid exits the bottom of T102 and is pumped through a refrigerated heat exchanger to cool it back to the required 1 to 2 ° C. The functional fluid exits the heat exchanger and is directed to contactor T101 through the spray nozzles that soak into the contactor package and the procedure is repeated. Little or nothing of the MonoChem is consumed in the procedure; any loss is replaced by a replenishment system of the MonoChem.

EXAMPLES OF USE A functional fluid was prepared and tested as follows: The functional fluid was tested in exhaust gas from a natural gas combustion gas turbine, operating at approximately 720 rpm. The NO ?, CO, 02 and C02 levels were monitored during a period of 1 hour. The results are shown in Table 1A and 1B. In experiments C-1A, C-2A and C-3A, the gas levels at the outputs were measured for 1 hour. In the experiments C-1 B, C-2B and C-3B the exhaust gases were passed through the functional fluid in a contact container, and the levels of the gases in the outlet were measured after passing through the fluid functional for 1 hour.

TABLE 1A TABLE 1B

Claims (56)

NOVELTY OF THE INVENTION CLAIMS

1. - A process for the preparation of a functional fluid comprising: reacting silicon, an alkali metal hydroxide and a solution comprising water and a chlorine source in a reaction vessel at a temperature not higher than about 95 ° C (200 F).

2. The process according to claim 1, further characterized in that the silicon and the alkali metal hydroxide are added to the reaction vessel before the addition of the solution comprising water and chlorine.

3. The process according to claim 1 or 2, further characterized in that the source of chlorine is chlorine gas or liquid chlorine.

4. The process according to claim 3, further characterized in that the source of chlorine is liquid chlorine.

5. The process according to claim 4, further characterized in that the water and the liquid chlorine are in a ratio of about 10: 1 about 30: 1 by volume.

6. The method according to claim 5, further characterized in that the water and the liquid chlorine are in a proportion of approximately 20: 1 by volume.

7. The process according to any of the preceding claims, further characterized in that the amount of silicon to alkali metal hydroxide is in a ratio of about 1: 5 to about 5: 1 by volume.

8. The process according to claim 6, further characterized in that the amount of silicon to alkali metal hydroxide is about 1: 1 by volume.

9. The process according to any of the preceding claims, further characterized in that the additional solution comprising water and liquid chlorine is added at a sufficient rate to maintain the reaction until one or more of the metal silicon or sodium hydroxide is spent. .

10. The process according to any of the preceding claims, further characterized in that the reaction temperature is not greater than about 80 ° C (175 ° F).

11. The process according to any of the preceding claims, further characterized in that the metal of the alkali metal hydroxide is lithium, sodium or potassium.

12. The process according to claim 11, further characterized in that the metal is sodium.

13. The process according to claim 12, further characterized in that the sodium hydroxide is in solid form.

14. - The process according to claim 12, further characterized in that the sodium hydroxide is in the form of an aqueous solution.

15. The method according to any of the preceding claims, further characterized in that the silicon is grade 441 metal silicon.

16. The process according to any of the preceding claims, further characterized in that the silicon comprises particles that have a diameter of average particle ranging from about 1 mm to about 150 mm.

17. The process according to claim 16, further characterized in that the silicon comprises particles having an average particle diameter ranging from about 24 mm to about 150 mm.

18. The process according to any of the preceding claims, further characterized in that the water is distilled water.

19. The process according to any of the preceding claims, further characterized in that the reactor vessel is open to the atmosphere.

20. The process according to any of claims 1-18, further characterized in that the reactor vessel is closed to the atmosphere.

21. - The process according to any of the preceding claims, further characterized in that the silicon and sodium hydroxide in solid form are charged at an equivalent height of about 30% of the volume of the reactor vessel, before the addition of the solution comprising water and liquid chlorine.

22. A functional fluid having a specific gravity of about 1.25 to 5, and a pH of about 9 to about 13, which is obtained by the process according to any of claims 1-21.

23. The functional fluid according to claim 22, further characterized in that it has a specific gravity of about 5, and a pH of about 9 to about 12, which is obtained by the process according to any of claims 1-21. .

24. The functional fluid according to claim 22 or

23, further characterized in that the alkali metal hydroxide is sodium hydroxide.

25. The functional fluid according to any of claims 22-24, further characterized in that the silicon is grade 441 metal silicon.

26.- The use of a functional fluid as claimed in any of claims 22-25. as an excluder of CO, C02 or H2S.

27. - The use of a functional fluid as claimed in any of claims 22-25 as an H2S excluder in wet oil and gas production systems.

28. The use of a functional fluid as claimed in any of claims 22-25 in the treatment of NOx and SOx gases.

29. The use of a functional fluid as claimed in any of claims 22-25 in acidulated gas treatment systems.

30. The use of a functional fluid as claimed in any of claims 22-25 as a corrosion inhibitor.

31. The use of a functional fluid as claimed in any of claims 22-25 as a carbon steel peacemaker to reduce the corrosion rate associated with acid gases.

32. The use of a functional fluid as claimed in any of claims 22-25 as an antifoaming agent.

33. The use of a functional fluid as claimed in any of claims 22-25 in the removal of residual water contaminants or boiler feed water. 34.- A process for the desulphurization of a gaseous hydrocarbon-based food supply comprising: (i) contacting the stored gaseous hydrocarbon feed with a functional fluid as claimed in any of claims 1-24

under suitable conditions to form a functional fluid enriched in sulfur; and 0) recovering a stored feed of desulphurized gaseous hydrocarbon from the functional fluid enriched in sulfur.

The method according to claim 34, further characterized by additionally comprising the steps of: (iii) contacting the functional fluid enriched in sulfur with a flocculating agent under conditions sufficient to allow the precipitation of sulfur from the functional fluid enriched in sulfur; and (iv) separating the sulfur precipitated from the fluid to recover a functional fluid as claimed in any of claims 1-24.

36.- The method according to claim 35, further characterized in that it further comprises the step of recycling the functional fluid for use in step (i) of claim 34.

37.- The method according to claim 36, characterized also because the pH of the recycled functional fluid is modified to be greater than about 12.

38.- The method according to claim 37, further characterized in that the pH of the recycled functional fluid is modified to approximately 13.

39.- The procedure according to claim 34, further characterized in that the stored hydrocarbon gas feed is predominantly natural methane gas.

40. - The method according to claim 34, further characterized in that the processing conditions are such that C02 is also removed from the stored hydrocarbon feed.

41.- A procedure for the removal of C02 from a stored hydrocarbon gas feed having a C02 component, comprising the steps of: (i) contacting the functional fluid and the stored hydrocarbon gas feed under pressure conditions elevated to dissolve C02 in the functional fluid; (ii) separating the stored feed of gaseous hydrocarbon from the functional fluid; (iii) depressurizing the functional fluid to cause evolution of the C02 gas in the functional fluid.

42.- The procedure according to claim 41, further characterized in that the stored hydrocarbon gas feed also comprises sulfur-containing compounds.

43.- The method according to claim 41 or claim 42, further characterized in that the functional fluid is provided at a temperature of less than 5 ° C.

44. The method according to claim 43, further characterized in that the functional fluid is provided at a temperature in the range from about 1 ° C to about 3 ° C.

45. - The method according to claim 44, further characterized in that the functional fluid is provided at a temperature of about 2 ° C.

46.- The method according to claim 41, further characterized in that it further comprises the step of liquefying the separated gas C02.

47.- The method according to claim 41, further characterized in that it further comprises the step of desulfurizing the stored hydrocarbon gas feed in step (ii) of claim 41, using the method of claim 34.

48.- A apparatus for use in the method of any of claims 34 to 40 comprising a first contactor, a second contactor placed downstream of the first contactor, and a separator placed downstream of the second contactor to substantially remove a solid from a liquid.

49. The apparatus according to claim 48, further characterized in that the separator is a plate filter press.

50.- The apparatus according to claim 48 or claim 49, further characterized in that it is when it is retro-fitted to a gas treatment plant for use in the partial treatment of a stored gas feed.

51. - An apparatus for use in the method of any of claims 41 to 47 comprising a contactor and a vessel for depressurization, placed downstream of the contactor.

52. A functional fluid according to any of claims 22 to 25 useful as a medicament. 53.- The use of a functional fluid as claimed in any of claims 22 to 25 in the manufacture of a medicine useful for the treatment of insect bites. 54.- The functional fluid according to any of claims 22 to 25 further characterized in that it is useful as a biocide. 55.- The use of a functional fluid as claimed in any of claims 22 to 25 in the manufacture of a medicament useful for the treatment of a viral and / or blood condition. 56.- A pharmaceutical composition comprising a functional fluid according to any of claims 22 to 25.