BR102014003010A2 - coal separation unit for a gasification system, high ash content gasification system and method for reducing the ash content of a high ash feed stream in a gasification system - Google Patents

Abstract

coal separation unit for a gasification system, high ash content coal gasification system and method for reducing the ash content of a high ash feed stream in a gasification system. It is a coal separation unit for a gasification system that includes a container having an upper part and a bottom part, a first inlet configured to receive a feed stream including at least coal and ash from a milling unit, a second inlet configured to receive a flushing fluid stream, a first outlet configured to carry a low ash feed stream, and a second outlet configured to carry a high ash stream. In operation, the feed stream is flushed with the wash fluid stream in the separation unit to separate at least a portion of the coal ash. the separated ashes decant to the bottom of the container and are transported through the second outlet as the high ash stream, the separated coal floats to the top of the container and is transported through the first outlet to a gasification unit as low ash feed flow

Description

“CHARCOAL SEPARATION UNIT FOR A GASIFICATION SYSTEM, HIGH CONTENT COAL GASIFICATION SYSTEM AND PAF1A METHOD REDUCE THE HIGH CONTENT OF A GASIFICATION HIGH CONTENT GRAY FEED FLOW FEEDING SYSTEM” Invention The field of the invention generally relates to gasification systems and more specifically to gasification systems for high ash content fuels.

Raw material, such as coal, petroleum coke, biomass, wood-based materials, agricultural waste, tar, coke oven gas and asphalt, and other carbon-containing items may be gasified for use in the production of electricity, chemicals, synthetic fuels, and for a variety of other applications. Gasification involves reacting a carbonaceous fuel and oxygen at a very high temperature to produce synthesis gas, a fuel containing carbon monoxide and hydrogen. Synthesis gas typically burns more efficiently and cleaner than the fuel in its original state prior to gasification. Synthesis gas can be used for power generation, chemical production, and any other suitable application. Some carbon-containing raw materials have an ash content, however, this makes these raw materials unsuitable for use in connection with some gasification systems.

Brief Description In one aspect, a coal separation unit is provided for a gasification system having a grinding unit and a gasification unit. The separation unit includes a container having an upper part and a bottom part, a first inlet configured to receive a feed stream including at least coal and ash from the grinding unit, and a second inlet configured to receive a flushing fluid flow. The separation unit further includes a first outlet configured to carry a low ash feed stream, and a second outlet configured to carry a high ash stream. In operation, the feed stream is flushed with the wash fluid stream in the separation unit to separate at least a portion of the coal ash. The separated ash settles to the bottom of the container and is transported through the second outlet as the high ash stream. The separated coal floats to the top of the container and is conveyed through the first outlet to the gasification unit as the low ash feed stream.

In another aspect, a high ash content coal gasification system is provided. The system includes a grinding unit configured to reduce the particle size of a high ash feed stream comprising at least coal and ash, a gasification unit configured to receive a low ash feed stream and produce a synthesis gas from the low ash feed stream, and a coal separation unit coupled between the grinding unit and the gasification unit. The separation unit includes a container having an upper part and a bottom part, a first inlet in flow communication with the milling unit and configured to receive the high particle size high ash feed stream, and a second inlet configured to receive a flush fluid flow. The separation unit further includes a first outlet coupled in flow communication with the gasification unit and configured to carry the low ash feed stream to it, and a second outlet configured to carry a high ash flow. . In operation, the high ash feed stream is flushed with the washer fluid stream in the separation unit to separate at least a portion of the ash from the coal. The separated ashes decant to the bottom of the container and are transported through the second outlet as the high ash stream, and the separated coal floats to the upper part of the container. It is conveyed to the gasification unit through the first outlet as the low ash feed stream.

In yet another aspect, a method is provided for reducing the ash content of a high ash feed stream in a gasification system. The method includes providing a coal separation unit, the separation unit including a container having an upper part, a bottom part, a first and second inlet, and a first and second outlet. The method further includes providing the high ash feed stream for the first inlet, the high ash feed stream that includes at least charcoal and ashes, ii providing a wash fluid stream for the second inlet, contacting the high ash feed stream with the wash fluid flow into the container, and separate at least a portion of the coal ash. The separated ashes decant to the bottom end of the container and the coal floats to the top of the container.

Brief Description of the Figures FIGURE 1 is a schematic view of an exemplary gasification system; FIGURE 2 is an exemplary detailed schematic view of the gasification system shown in FIGURE 1; and FIGURE 3 is a cross-sectional view of an exemplary coal separation unit for use in the gasification systems shown in FIGURES 1 and 2.

Detailed Description FIGURE 1 is a simplified schematic illustration of an exemplary gasification system 10 including a grinding unit 12, a coal separation unit 14, a gasification unit 16, a black water handling unit 18, a gray water handling unit 20, and an air separation unit (ASU) 22. In the exemplary embodiment, coal is described as the raw material for gasification system 10. However, any other suitable type of material may be used as raw material for gasification system 10.

As used herein, the terms "high ash" and "low ash" are used in a relative sense, and high ash means a gray content greater than approximately 20%, and low ash means an ash content of less than approximately 20%.

In the exemplary embodiment, milling unit 12 receives a high ash content coal feedstock (i.e. ash content greater than 20%) (not shown), reduces the coal to a predetermined particle size , and conveys a coal feed stream 24 to the separation unit 14. The coal and ashes are separated into the separation unit 14, as further described herein, to produce a high ash flow 26 and a feed stream. low ash feed 28. Gasification unit 16 receives a fluid flow 30 from ASU 22 and a low ash feed flow 28 and produces a synthesis gas flow 32. At least a portion of the Synthesis gas stream 32 is conveyed to the black water handling unit 18 and gray water handling unit 20 for removal of impurities from the synthesis gas flow. FIGURE 2 is a detailed schematic system view of exemplary gasification 10. In the exemplary embodiment, gasification system 10 includes a generation facility 100 that can produce and / or burn a synthetic gas, ie synthesis gas, to conversion to electricity and / or to make chemicals. For example, it should be understood that while the exemplary embodiment illustrates electricity generation with a power island I 166, other embodiments may optionally not include power island 166. For example, other installation embodiments 100 may include chemical installations, synthesis gas production facilities, and any other suitable industrial installation. for the production of synthesis gas-based chemicals and chemical compositions.

In the exemplary embodiment, a raw material 102 (e.g., high ash content coal) and a flux 104 are transported to a raw material handling and storage unit 106. The flux 104 may be added to the raw material 102 in the raw material handling and storage unit 106 to adjust the melting behavior of the raw material 102. The flux 104 may include, for example, sand, rock, limestone, bauxite, and iron ore. The raw material handling and storage unit 106 directs the raw material 102 and flux 104 mixture into a pulp milling and preparation unit 108 which resizes or reformats the flux raw material mixture 104 by cutting, grinding, shredding, spraying, briquetting, or I

It is pelleting raw material 102 and fluxantie 104 to generate gasification fuel. Additionally, a water feed 110 and / or reagent '244, or other suitable fluids may be added to the raw material 102 and flux mixture 104 in the pulp milling and preparation unit 108 to create a pulp fuel 112.

In the exemplary embodiment, pulp fuel 112 is conveyed to separation unit j14. The feed to the separation unit 14 may include a solid feed, a liquid feed, and / or a gas feed. Separation upright 14 includes a separation type flotation column 00 (shown in FIGURE 3) which separates pulp fuel 112 into a high ash stream 114 and a low ash feed stream. 116, as further described herein. The high ash stream 114 is conveyed as a waste stream, a product stream, or is used for other suitable processes, and the low ash feed stream 116 is conveyed to a carbonator 118. In the exemplary embodiment , aerator 118 is a drag stream aerator configured to receive feed stream 116 as a paste.

In the exemplary embodiment, aerator 118 converts feed stream 116 into a synthesis gas, for example, a combination of carbon monoxide and hydrogen. This conversion can be accomplished by subjecting the fuel to a controlled amount of any moderator and limited oxygen at high pressure (e.g., between about 40 bar and 90 bar) and elevated temperatures (for example, between about 1200 ° C and 150 ° C). C) depending on the type of fuel used. Heating of fuel during a pyrolysis process can generate slag 120 and waste gases (eg carbon monoxide, hydrogen, and nitrogen).

In the exemplary embodiment, then a partial oxidation (i.e. gasification) process on a gasifier 118 may occur. To aid the gasification process, an oxygen flow 122 is supplied to gasifier 118 from ASU 22, which operates to separate air 124 into component gases. ASU 22 separates air 124 into oxygen 122 and nitrogen 126, and oxygen 122 is directed to gasifier 118 and o. nitrogen 126 may be transported to other components or processes in system 10. -.

In the exemplary embodiment, coal and waste gases may react with oxygen 122 to form carbon dioxide and carbon monoxide, which provide heat for subsequent gasification reactions. Temperatures during the gasification process may range from approximately 1200 ° C to approximately 1500 ° C. Additionally, steam (not shown) may be introduced into gasifier 118 to allow some raw material to be burned to produce carbon monoxide and energy, which can trigger a second reaction that additionally converts raw material into hydrogen and additional carbon dioxide.

In the exemplary embodiment, a resulting synthesis gas stream 128 and slag 120 are produced by aerator 118. Slag 120 is conveyed to a coarse slag handling system 130 which produces coarse slag 132 to be sold as a product, and the flow Synthesis gas 128 is conveyed to a scrubber 134 to remove certain particulate matter and other pollutants. In the exemplary embodiment, any suitable debugging technique may be used. For example, the scrubber 134 may utilize a water-supplied water spray from a condensate return 136 and a gray water return 138. Synthesis gas flow 128 may contact the water spray as it condenses certain condensables such as like tar and oil. The synthesis gas stream 128 may also be cooled to remove particulate matter. In the exemplary embodiment, the scrubber 134 produces a water 144 containing particulate matter removed from the synthesis gas stream 128 during the scrubbing process. Water 144 is directed to a water expansion system 146 to expand water 144 into an expanded gas. In the exemplary embodiment, a high ash content pulp or coal feed 212 is fed from the milling 12 for a column inlet 214 located in a collection zone 208 that is oriented below a cleaning zone 210. Fluid flushing unit 202 supplies a fluid 216 (e.g., water) through one or more inlets 218 at the top of the column to create a generally downward stream of scrubbing fluid 220 that contacts feed 212 entering column 200 through inlet 214. Contact between scrubbing fluid 220 and feed 212 facilitates the separation of ash and charcoal contained in the high ash content coal feed 212. The ashes are typically hydrophilic, and the separate ashes 222 will tend to move downward and settle on a bottom 224 of the column. In contrast, coal is typically hydrophobic, and separate coal 226 will tend to float and move upward to a top 228 of column 200. Separate ashes 222 are removed from column 200 through outlet 230 as a stream. high ash content 232, and separate coal 226 is removed from column 200 through outlet 234 as a low ash feed stream 236 which is conveyed to gasification unit 16.

In the exemplary embodiment, the separation of ash and coal contained in the high ash content coal 212 is further facilitated by air unit 204 and reagent unit 206. Air unit 204 provides an air supply 238 for inlet 240 located at the bottom of column 224. As such, air supply 238 generates air bubbles 242 that create turbulent flow within the scrubbing fluid 220 to facilitate separation of the high ash content coal feed 212 and to increase the upstream of the separated coal 226. In the exemplary embodiment, reagent unit 206 provides a reagent feed 244 for coal feed 212. As such, reagent feed 244 increases the hydrophobicity of coal in coal feed 212 to facilitate upward flow of separate coal 226. In the exemplary embodiment, reagent feed 244 is diesel and / or a a glycol-containing composition. Alternatively, reagent feed 244 is any composition that enables system 14 to function as described herein | document.

In operation, the milling unit 12 supplies the high ash content coal feed 212 through the inlet 214 in the separating column 200. The fluid flushing unit 202 provides downflow of flushing fluid 220 through (s) ) inlet (s) from column (s) 218 to contact feed 212 and subject feed 212 to a foam flotation process to separate the ash and coal from feed 212. As such, the separated ashes 222 decant to the bottom. from column 224, and separate carbon 226 floats to the top of column 228. Feed 212 is further separated by injecting air supply 238 through column inlet 240 to generate upstream air bubbles 242 and injecting reagent feed 244 through column inlet 246 to increase the hydrophobicity of coal. Separate ash 222 collected at the bottom of column 224 is removed from column 200 through outlet 230, and separate coal 226 is removed from column 200 through outlet 234 as low ash flow 236. In the exemplary embodiment, the process of Foam flotation of the separation unit 14 produces low ash flow 236 with an ash content of less than 20%, and flow 236 can be subsequently treated in a pulp thickening / thinning system 248 to produce a pulp. low ash coal 250 with a solid content of at least 40% (by weight), which is then transported to gasification unit 16 for synthesis gas production. In an alternative embodiment, the separation unit 14 produces low ash flux 236 with an ash content of less than 10%. As described herein, systems and methods are provided for reducing the ash content of high ash content fuels such as high ash content coal. High ash content fuel is foamed to separate ash from the fuel to produce a low ash paste. Typically, drag stream gasification is not an efficient method for gasifying high ash containing fuel. The systems and methods described herein enable drag stream gasification systems to use high-content fuels, thereby allowing access to otherwise unusable coal or fuel sources. Additionally, these systems and methods reduce or eliminate the cost associated with coal beneficiation, which is a process for reducing non-combustible fuel content and improving fuel quality. As such, the systems and methods described herein enable gasification systems to use fuels from markets such as India and South America, which have vast reserves of low cost high ash content.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention! which includes making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. It is understood that these other examples are within the scope of the claims if they themselves have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with minor differences from the literal language of the claims.

Claims (20)

1. COAL SEPARATION UNIT FOR A GASIFICATION SYSTEM, which has a grinding unit and a gasification unit, said coal separation unit comprising: a container having an upper part and a bottom part; a first inlet configured to receive a feed stream comprising at least coal and ash from the grinding unit; a second inlet configured to receive a flush fluid flow; a first outlet configured to carry a low ash feed stream; and a second outlet configured to transpose a high ash stream, wherein in operation, the feed stream is flushed with the wash fluid stream in said coal separation unit to separate at least a portion of the coal ash. wherein the separated ashes decant to said bottom part of said container and are transported through said second outlet as the high ash stream, and the separated coal floats to said upper part! of said container and is conveyed through said first outlet to the gasification unit as the low ash feed stream. The charcoal separation unit of claim 1, wherein said coal separation unit further comprises a third inlet configured to receive an air flow to facilitate the separation of coal and ash from the feed stream and / or flow of coal to said upper part of the container. The COAL SEPARATION UNIT according to claim 1, wherein said carbon separation unit is configured to receive a reactant stream to increase the hydrophobicity of the coal, and wherein the reactant stream is mixed with the reactant. high ash feed flow before said first inlet. The COAL SEPARATION UNIT according to claim 3, wherein said coal separation unit comprises that the reactant stream comprises at least one of diesel and glycol based composition. The COAL SEPARATION UNIT according to claim 2, wherein said coal separation unit comprises said third inlet being located at the bottom of said container. The COAL SEPARATION UNIT according to claim 1, wherein said coal separation unit comprises said second inlet being located in the upper part of said container. The COAL SEPARATION UNIT according to claim 1, wherein said coal separation unit comprises said first outlet being located in said upper part of said container and said second outlet being located in said part of said container. bottom of said container. 8. HIGH GRAY CONTENT COAL GASIFICATION SYSTEM, said system comprising: a grinding unit configured to reduce the particle size of a high ash feed stream comprising at least coal and ash ; a gasification unit configured to receive a low ash feed stream and produce a synthesis gas from the low ash feed stream; and a carbon separation unit coupled between said milling unit and said gasification unit, wherein said carbon separation unit comprises: a container having an upper part and a bottom part; a first input in flow communication with said milling unit and configured to receive the high ash feed stream having reduced particle size; a second inlet configured to receive a flush fluid flow; a first outlet coupled in flow communication with said gasification unit and configured to carry the low ash feed stream thereon; and a second outlet configured to carry a high ash stream, wherein in operation, the high ash feed stream is flushed with the wash fluid stream in said coal separation unit to separate at least one part of the ashes the coal, the separated ashes decant to said bottom part of said container and are carried through said second outlet as the high ash stream, and the separated coal floats to said upper part of said container and is conveyed to said gasification unit through said first outlet as the low ash feed stream. A system according to claim 8, wherein said system comprises that said carbon separation unit further comprises a third inlet configured to receive an air flow to facilitate separation of charcoal and ash from the feed stream. and / or the flow of coal to said upper part of the container. A system according to claim 8, wherein said system comprises said carbon separation unit being configured to receive a reagent stream to increase the hydrophobicity of the coal, and wherein the reactant stream is mixed with the reactant stream. high ash feed flow before said first inlet. A system according to claim 10, wherein said system comprises that the reactant flow comprises at least one of diesel and glycol based composition. A system according to claim 9, wherein said system comprises said coal separation unit being configured to receive the high ash feed stream with an ash content greater than 20%, and To produce the low ash feed stream I cut an ash content of less than 20%. { A system according to claim 8, wherein said system comprises said secure inlet being located in said upper part of said container. j A system according to claim 8, wherein said system comprises said first outlet being located in said upper part of said container and said second outlet being located in said bottom part of said container. 15. METHOD FOR REDUCING THE GRAY CONTENT OF A HIGH GRAY FEED FEED FLOW IN A GASIFICATION SYSTEM. container having an upper part, a bottom part, a first and second inlet, and a first and second outlet; provide the high ash feed stream for the first inlet, the high ash feed stream including at least coal and ash; providing a flow of flushing fluid to the second inlet; contacting the high ash feed stream with the wash fluid stream in the container; and separating at least a portion of the coal ashes, wherein the separated ashes decant to the bottom of the container and the coal floats to the top of the container. The method of claim 15, wherein said method further comprises coupling a grinding unit to the coal separation unit and producing the high ash feed stream in the grinding unit. The method of claim 15, wherein said method further comprises extracting a low ash feed stream from the first outlet and extracting a high ash stream from the second outlet. The method of claim 17, wherein said method further comprises conveying the low ash feed stream to a gasifier. The method of claim 15, wherein said method further comprises providing a third inlet in the container and providing an air flow to the third inlet to facilitate separation of the coal ash from the high feed content stream. ashes and / or the flow of coal to the top of the container. The method of claim 15, wherein said method further comprises providing a reactant stream to the high ash feed stream prior to the first inlet, wherein the reactant stream increases the hydrophobicity of the can /. high ash feed flow.