MXPA99011280A - Acid gas solvent filtration system - Google Patents

Abstract

La invención es un proceso para separar los gasesácidos de gas sintético, y tratar los sólidos resultantes. Una mezcla que comprende el gas sintético y gasácido se pone en contacto con un fluido que reacciona con el gasácido para formar un sólido particulado disperso en un fluido. La suspensión que comprende el fluido y el sólido particulado se filtra para separar el sólido particulado del fluido por medio de un filtro regenerarle. Los sólidos particulados son removidos del filtro regenerarle por relavado con fluido de relavado para formaruna suspensión bombearle que comprende una mezcla de sólidos particulados y fluido de relavado. La suspensión es gasificada para formar gas sintético y sólidos vitrificados.

Description

ACID GASEOUS SOLVENT FILTRATION SYSTEM FIELD OF THE INVENTION The invention relates to the removal of acid gas gases (synthetic gas), and more particularly to the separation and recycling of the particulate solids resulting from the gasification reactor.

BACKGROUND OF THE INVENTION Gas production from carbonaceous solids and liquids, especially coal, coal, and liquid hydrocarbon feeds, has been used for a considerable period of time and has recently experienced significant improvements due to the increased demand for Energy. The gas can be produced by heating carbonaceous fuels with reactive gases, such as air or oxygen, often in the presence of steam in a gasification reactor to obtain the fuel gas, which is extracted from the bottom of the gasification reactor. The gassin is then subjected to several cleaning operations to release it from the different pollutants that are formed or are released from the feed during the gasification operation. These materials can easily contaminate the steam process units if they are not properly treated during the gasification operation. For example, materials frequently found in gassin include hydrogen sulfide, ammonia, cyanides, and particles in the form of carbon and trace metals. The degree of contaminants in the feed is determined by the type of feed and the particular gasification process used, as well as the operating conditions. In any case, the removal of these pollutants is critical to make gasification a viable process. When the gaseous product is discharged, the gasifier is usually subjected to a cooling and cleaning operation that involves a purification technique where the gas is introduced in a depuration and put in contact with a spray of water which cools the gas and removes the particles and ionic constituents of the gassin. The initially cooled gas can then be treated to desulfurize the gas before the use of the gaseous product.

BRIEF DESCRIPTION OF THE INVENTION The invention is a process for separating acid gases from synthetic gas and treating the resulting solids. A mixture comprising synthetic gas and acid gas is contacted with a fluid which reacts with the acid gas to form a suspension of particulate solids dispersed in a fluid and synthetic gas. The suspension comprising fluid and particulate solids is separated from the synthetic gas in the conventional separator or by other means. The suspension is then filtered to remove the particulate solids from the fluid by means of a regenerable filter. The particulate solids are removed from the regenerable filter by washing again with a rewet fluid to form a pumpable suspension comprising a mixture of particulate solids and rewet fluid.

DETAILED DESCRIPTION OF THE INVENTION As used herein, a "fluid that reacts with acid gas" includes fluids that preferentially dissolve acid gases, as well as fluids containing one or more compounds that are dissolved, dispersed or suspended therein and that they react with acid gases. The fluid itself can be an inert fluid. As used herein, "acid gases" comprises hydrogen sulfide, carbon dioxide or a mixture thereof. Other acid gases may be present in traces.

The fluid can react with one or both of these acid gases. Typical fluids may include an amine such as ethanolamine. The fluids can be solvents such as lower monohydric alcohols, such as methanol, or polyhydric alcohols such as ethylene glycol and the like. . As used herein, "synthetic gas" or "gassin" comprises the gas comprising carbon monoxide, hydrogen and occasionally inert gases such as nitrogen. How it is used here, a "regenerable filter" is a filter that, when it is charged and partially clogged with solids, can be regenerated. Regeneration is usually done by removing the service filter, and then inverting the flow direction and the relieved particles from the filter face. The relieved material is a suspension that is advantageously isolated from the process vapor. Then, when enough material has been replenished, the flow direction is reversed again and the filter is put back into service. The invention is a process for separating acid gases from a synthetic gas and treating the resulting solids. Gassing can be produced by heating carbonaceous fuels with reactive gases, such as air or oxygen, often in the presence of steam in a gasification reactor to obtain the fuel gas which is extracted from the gasification reactor. The gas thus manufactured often contains contaminants such as acid gases. A mixture comprising the synthetic gas and acid gas is contacted with a fluid which reacts with the acid gas to form a particulate solid dispersed in a fluid and synthetic gas. The contact is usually in a tower of trays or counter-current bubbles, but any type of contact scrubber can be used, including the jet scrubber, inverted jet scrubbers and venturi scrubbers. The type of contact apparatus is not important. Similarly, the type of fluid that reacts with the acid gas is not important. There are many fluids, particles and suspensions known in the art to remove acid gases. See, for example, US Patent 4,039,619, US Patent 4,052,176, US Patent 4,496,371, US Patent 4,769,045, US Patent 5,289,676 and US Patent 5,447,702, the disclosures of which are incorporated herein by reference. The fluid may contain an amine such as diethanolamine, methanol, N-methyl-pyrrolidone, or a dimethyl ether of polyethylene glycol. The fluid may contain particulate iron, caustic salts, carbonates, iron oxides, nickel, nickel oxides or a combination thereof. The suspension comprising the fluid and particulate solids is separated from the synthetic gas in a separation zone in a tower, in a conventional separator, or by other means. The separation of a suspension from a gas is well known in the art. The suspension is then filtered to remove the particulate solid from the fluid by means of a regenerable filter. It is often advantageous to have preconcentration steps such as sedimentation in a settler or centrifugation to increase the charge of solids in the suspension before filtration. However, the suspension can be filtered without preconcentration. The suspension is filtered by being forced by a pressure flow through the filters. The filters remove a fraction, often greater than 70%, of the solids in the suspension. The filters allow the fluid, and occasionally some solids, to pass through and be recycled to the contactor. When those solids accumulate on the filter, it forms the filter cake. The pressure difference increases until it reaches a point where the flow through the flow is damaged. At some point before the filter is completely clogged, the filter is removed from service. The fluid that reacts with the acid gas is expensive, so that it may be advantageous to displace this fluid with a less expensive rewetting fluid. It is preferred to displace the fluid that reacts with the acid gas through the filter in the same direction that the process normally flows, so as not to load the fluid that reacts with the acid gas with solids. The fluid that displaces the fluid that reacts with the acid gas is not critical. The fluid that reacts with the acid gas can be displaced with, among other things, water, a hydrocarbon, an alcohol, a gas, or a vapor. It is advantageous to displace the fluid that reacts with acid gas with the rewet fluid. The particulate solids are removed from the regenerable filter by rewetting with a rewet fluid to form a pumpable suspension comprising a mixture of particulate solids and rewet fluid. This suspension can be treated as waste or it can be recycled to the gasification reactor where the organic products will be degassed, and the particles will be vitrified, thereby doing both environmentally hazardous things. The rewet fluid should be compatible with its subsequent phase. The rewet fluid may be water, a hydrocarbon, an alcohol or other compatible fluid. Of course, it may be simpler and more economical to use a fluid that reacts with the acid gas as the rewet fluid. The rewet fluid does not necessarily need to be miscible with the fluid that reacts with the acid gas, although it is often advantageous to do so. Water is often preferred, since water is cheap and can itself be a residual flow of another process.

The regenerable filter can be any kind of relavable filter. A preferred commercial modality is the sleeve filter. This is a cloth filter that covers an interior support in which fluids can enter and be extracted. The process steam flows from the outer side of the sleeve, through the fabric of the sleeve, and into the inner support. The solids accumulate on the outer side of the sleeve until they are replenished. It is advantageous to have two or more sleeves capable of operating in parallel in a system. A control system can place a filter out of line isolating it from the contactor. Next, advantageously, the fluid that reacts with the acid gas can be displaced from the filter. Finally, the fluid can be injected through the central support and out through the sleeve at a rate sufficient to remove the particulate solids. Then, the rewet fluid is advantageously displaced by the fluid that reacts with the acid gas, and the filter is put back into service. It is advantageous if the suspension is pumpable. This reduces the costs of handling or handling, and allows easy recycling to the gasification reactor. The liquid and any organic compounds are gasified in the reactor. The solids are vitrified, which stabilizes the solids for non-hazardous waste.

Claims (12)

CHAPTER CLAIMEDICATORÍO Having described the invention, it is considered as a novelty and, therefore, the content is claimed in the following CLAIMS:

1. A process for separating acid gases from synthetic gas, characterized in that it comprises a. contacting a mixture comprising synthetic gas and acid gas with a fluid that reacts with the acid gas to form a particulate solid dispersed in a fluid and synthetic gas, b. separating the synthetic gas from a suspension comprising fluid and particulate solids, c. separating the particulate solids from the fluid by means of a regenerable filter, d. relieving the particulate solids of the regenerable filter with a rewet fluid to form a pumpable suspension comprising a mixture of particulate solids and rewet fluid.

2. The process according to claim 1, characterized in that the fluid reacts with acid gas comprising an amine.

3. It processed according to claim 1, characterized in that the particulate solid comprises iron sulfide. .

4. The process according to claim 1, characterized in that the rewind fluid comprises water.

5. The process according to claim 1, characterized in that the fluid that reacts with the acid gas comprises an iron compound.

6. The process according to claim 1, characterized in that the regenerable filter is a sleeve filter. The process according to claim 1, characterized in that the plurality of sleeve filters is used in step (c). The process according to claim 1, characterized in that the separation of the particulate solids from the fluid is by means of at least one of at least two regenerable filters, and because it also comprises the step of controlling the process so that at least a filter separates the particulate solids from the fluid that reacts with the acid gas while at least one regenerable filter is replenished. 9. The process according to claim 1, characterized in that the fluid that reacts with the acid gases in step (a) is used as a rewind fluid in step (d). The process according to claim 1, characterized in that it further comprises pumping the pumpable suspension to a gasification reactor, where the suspension is gasified to form synthetic gas and vitrified solids. The process according to claim 1, characterized in that the rewet fluid comprises a compound selected from the group consisting of a hydrocarbon, an alcohol, water and mixtures thereof. The process according to claim 1, characterized in that it further comprises replacing the fluid which reacts with an acid gas of the regenerable filters with a compound selected from one or more of a hydrocarbon, an alcohol, water, or other rewet fluid before the wash.