CN214457793U

CN214457793U - Coal gasification conversion system and coal gasification synthetic ammonia system

Info

Publication number: CN214457793U
Application number: CN202120348514.1U
Authority: CN
Inventors: 宋文健; 杨科; 鲁思达; 张�林; 于经伟; 杨伟东; 李晓鹏
Original assignee: Beijing Aerospace Innovation Patent Investment Center (limited Partnership); Xi'an Aerospace Yuan Dongli Engineering Co ltd
Current assignee: Beijing Aerospace Innovation Patent Investment Center (limited Partnership); Xi'an Aerospace Yuan Dongli Engineering Co ltd
Priority date: 2021-02-07
Filing date: 2021-02-07
Publication date: 2021-10-22
Anticipated expiration: 2031-02-07

Abstract

The utility model discloses a coal gasification conversion system and coal gasification synthetic ammonia system. The coal gasification conversion system comprises: the fixed bed gasification furnace is provided with a gasification chamber and a coal gas outlet communicated with the gasification chamber, and is used for gasifying raw material coal to generate crude synthesis gas; an inlet of the communicating pipe is connected with a coal gas outlet of the fixed bed gasification furnace; the water-coal-slurry gasification furnace is provided with a combustion chamber, a crude synthesis gas inlet communicated with the combustion chamber and a water-coal-slurry nozzle communicated with the combustion chamber, wherein the crude synthesis gas inlet is positioned at the top of the water-coal-slurry gasification furnace and is connected with an outlet of a communicating pipe, and the water-coal-slurry gasification furnace carries out secondary gasification on the crude synthesis gas to obtain synthesis gas.

Description

Coal gasification conversion system and coal gasification synthetic ammonia system

Technical Field

The utility model belongs to the technical field of the coal chemical industry, concretely relates to coal gasification conversion system and coal gasification synthetic ammonia system.

Background

Coal, as a fossil fuel, is one of the indispensable energy sources for people to produce and live at present and even for a long time in the future. If coal is directly combusted, a large amount of resources are wasted, and SO is discharged₂、NO_xAnd harmful gases such as CO, etc., causing environmental pollution. Therefore, promoting clean utilization of coal has become a necessary choice for industry development.

Coal gasification is one of the important ways for clean utilization of coal. The existing coal gasification technology is that coal is added into a fixed bed gasification furnace and reacts with a gasification agent under pressure to prepare synthesis gas. The synthesis gas is generally treated by a direct water washing, temperature reduction and impurity removal process. Due to the high content of phenol, tar, aliphatic hydrocarbon and the like in the obtained synthesis gas, the synthesis gas has low quality, and a large amount of wastewater containing high-concentration organic matters, ammonia nitrogen, cyanide and other toxic substances can be generated in the subsequent treatment process. If the waste water is directly discharged or does not reach the standard after treatment, the environment is seriously polluted. The treatment cost of wastewater discharge after reaching standards is very high, and heavy burden is brought to enterprises.

SUMMERY OF THE UTILITY MODEL

The utility model discloses the first aspect provides a coal gasification conversion system, and the system includes:

the fixed bed gasification furnace is provided with a gasification chamber and a coal gas outlet communicated with the gasification chamber, and is used for gasifying raw material coal to generate crude synthesis gas;

an inlet of the communicating pipe is connected with a coal gas outlet of the fixed bed gasification furnace;

the water-coal-slurry gasification furnace is provided with a combustion chamber, a crude synthesis gas inlet communicated with the combustion chamber and a water-coal-slurry nozzle communicated with the combustion chamber, wherein the crude synthesis gas inlet is positioned at the top of the water-coal-slurry gasification furnace and is connected with an outlet of a communicating pipe, and the water-coal-slurry gasification furnace carries out secondary gasification on the crude synthesis gas to obtain synthesis gas.

The second aspect of the utility model provides a coal gasification synthetic ammonia system, the system includes according to the utility model discloses a coal gasification conversion system.

The utility model discloses a coal gasification conversion system, through the advantage complementation with fixed bed gasifier and coal slurry gasifier, can obtain the synthesis gas product of high quality. The content of phenol, tar, aliphatic hydrocarbon and the like in the synthesis gas is reduced, and the problem of wastewater treatment can be effectively relieved. CH in syngas₄The content is reduced, and the catalyst can be used as raw material gas for synthesizing ammonia, and is favorable for reducing the purge gas amount and energy consumption of an ammonia synthesis system.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required to be used in the embodiments of the present invention will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a flow chart of a coal gasification conversion system according to an embodiment of the present invention.

Fig. 2 is a flow chart of another coal gasification conversion system according to an embodiment of the present invention.

FIG. 3 is a flow diagram of a coal gasification ammonia synthesis system according to an embodiment of the present invention.

FIG. 4 is a flow diagram of another coal gasification ammonia synthesis system according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantageous effects of the present invention more clear, features and exemplary embodiments of various aspects of the present invention will be described in detail below. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. In the drawings and the following description, at least some well-known structures and techniques have not been shown in detail in order to avoid unnecessarily obscuring the present invention; also, the dimensions of some of the structures may be exaggerated for clarity. Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

In the description of the present invention, it is to be noted that, unless otherwise specified, "above" and "below" are inclusive; "plural" and "several" mean two or more; the terms "upper", "lower", "left", "right", "inner", "outer", and the like, indicate orientations or positional relationships only for convenience in describing the present invention and to simplify the description, but do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

The directional terms appearing in the following description are directions shown in the drawings and do not limit the specific structure of the embodiments of the present invention. In the description of the present invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "mounted" and "connected" are to be interpreted broadly, e.g., as either a fixed connection, a removable connection, or an integral connection; can be directly connected or indirectly connected. The specific meaning of the above terms in the present invention can be understood as the case may be, by those of ordinary skill in the art.

The above summary of the present invention is not intended to describe each disclosed embodiment or every implementation of the present invention. The following description more particularly exemplifies illustrative embodiments. At various points throughout this application, guidance is provided through a list of embodiments that can be used in various combinations. In each instance, the list is merely a representative group and should not be construed as exhaustive.

Firstly, a coal gasification conversion system provided by the utility model is explained. Fig. 1 shows a coal gasification conversion system as an example. Referring to fig. 1, the present invention provides a coal gasification conversion system including a fixed bed gasification furnace 100, a coal water slurry gasification furnace 200, and a communication pipe 300 connected between the fixed bed gasification furnace 100 and the coal water slurry gasification furnace 200.

The fixed-bed gasification furnace 100 may employ a type known in the art. The fixed bed gasification furnace 100 may be a slag solid gasification furnace or a slag liquid gasification furnace. The fixed-bed gasification furnace 100 has a gasification chamber 110 and a coal gas outlet 120 communicating with the gasification chamber 110. The fixed bed gasification furnace 100 is further provided with a feed inlet 130 at the top of the furnace body, a slag discharge port 140 at the bottom of the furnace body, and a gasification agent nozzle 150 at the side wall of the furnace body. Generally, the gasification chamber 110 may include a drying zone, a retort zone, a gasification zone, a combustion zone, and a slag zone in a direction from the feed inlet 130 to the slag discharge outlet 140. The slag zone can be either an ash zone (slagging solids) or a slag zone (slagging liquid). The gas outlet 120 is typically located in the side wall of the furnace body and may be located between the drying zone and the feed inlet 130. The gasifying agent nozzle 150 is arranged on the side wall of the furnace body corresponding to the combustion zone. Generally, more than 1 (e.g., 4 to 6) gasifying agent nozzles 150 are distributed along the circumferential direction of the side wall of the furnace body.

The fixed bed gasifier 100 generally uses lump coal as a raw material, and reacts with a gasification agent under pressurization to prepare synthesis gas, and has the advantage of wide raw material adaptability. For example, the raw material coal may be selected from anthracite, bituminous coal, lignite, and the like. In the fixed bed gasification furnace 100, raw material coal is fed from a furnace top feed inlet 130, and after passing through five regions of a drying region, a dry distillation region, a gasification region, a combustion region and a slag region (ash region) in turn, the residual slag (ash) after reaction is discharged from a furnace bottom slag discharge port 140. The gasifying agent is added into the combustion zone from a gasifying agent nozzle 150 to participate in the gasification reaction. The gas in the furnace moves from bottom to top, and the sensible heat of the gas can be fully utilized. The raw synthesis gas is finally sent out through the gas outlet 120. The main components of the crude synthesis gas are CO and H₂、CO₂And entrains more phenol, tar and aliphatic hydrocarbon (such as CH) generated in the dry distillation zone₄) And the like.

The coal-water slurry gasification furnace 200 has a combustion chamber 210, a raw synthesis gas inlet 220 communicating with the combustion chamber 210, and a coal-water slurry nozzle 230 communicating with the combustion chamber 210. The raw synthesis gas inlet 220 is positioned at the top of the coal-water slurry gasification furnace 200. The inlet of the communicating pipe 300 is connected to the gas outlet 120 of the fixed-bed gasification furnace 100, and the outlet of the communicating pipe 300 is connected to the raw synthesis gas inlet 220 of the coal-water slurry gasification furnace 200. The raw synthesis gas generated from the fixed-bed gasification furnace 100 is fed into the combustion chamber 210 from the top of the coal-water slurry gasification furnace 200 through the communicating pipe 300, and flows downward along the axis of the combustion chamber 210. The furnace entering flow direction of the synthesis gas is consistent with the final flow direction of fluid in the furnace, so that the flow field is relatively stable.

In some embodiments, the raw syngas inlet 220 is located at an intermediate position at the top of the coal-water slurry gasifier 200. Specifically, the raw syngas inlet 220 is centered on the central axis of the combustion chamber 210. The raw syngas is injected into the combustion chamber 210 along the axis of the combustion chamber 210 and perpendicular to the cross section of the combustion chamber 210, which facilitates the raw syngas to be uniformly distributed to the whole cross section of the combustion chamber 210, i.e. the uniform distribution is more effective. Therefore, the crude synthesis gas can be fully mixed with the coal water slurry and the oxygen, and the chemical reaction efficiency is improved.

The coal-water slurry nozzle 230 may be provided at a portion of the coal-water slurry gasification furnace 200 corresponding to the upper half of the combustion chamber 210. The number of the coal-water slurry nozzles 230 may be one or more than two. For example, the number of the coal-water slurry nozzles 230 is 1, 2, 3, or 4, etc.

In some embodiments, a plurality of coal-water slurry nozzles 230 are distributed along the circumference of the raw syngas inlet 220 at the top of the coal-water slurry gasifier 200. As an example, the raw synthesis gas inlet 220 is located at the middle position of the top of the coal-water slurry gasification furnace 200, and the plurality of coal-water slurry nozzles 230 are uniformly distributed around the center of the raw synthesis gas inlet 220 and on the same circumference of the raw synthesis gas inlet 220. Thus being beneficial to the full mixing of the coal water slurry, the oxygen and the raw synthesis gas so as to carry out full chemical reaction. As a specific example, the furnace wall FW of the coal-water slurry gasification furnace includes a side wall SW and an upper head HW connected to a top end of the side wall SW. The raw synthesis gas inlet 220 is located in the middle of the upper head HW. The plurality of coal water slurry nozzles 230 are disposed on the upper head HW, and are uniformly distributed around the same circumference of the raw synthesis gas inlet 220 with the center of the raw synthesis gas inlet 220 as the center of circle.

In these embodiments, the coal-water slurry nozzles 230 are preferably arranged obliquely with respect to the central axis of the combustion chamber 210. Further, the angle of inclination is 15 to 45 degrees, alternatively 20 to 35 degrees, or 25 to 40 degrees, or 30 to 45 degrees, or the like. The inclination angle of the water-coal-slurry nozzle 230 is in a proper range, which is convenient for opening a hole at the top of the water-coal-slurry gasification furnace 200 to install the water-coal-slurry nozzle 230, simultaneously realizes the sufficient mixing of the water-coal-slurry, the oxygen and the crude synthesis gas, and enables the whole mixed fluid to vertically flow downwards to perform sufficient chemical reaction, so that the content of phenol, tar and aliphatic hydrocarbon in the obtained synthesis gas is low, and the components of the synthesis gas are stable.

In some embodiments, the coal-water slurry gasification furnace includes a sidewall SW and an upper head HW connected to a top end of the sidewall SW, and the plurality of coal-water slurry nozzles 230 may be distributed on the sidewall SW along a circumferential direction of the sidewall SW. Preferably, the distance between the water-coal-slurry nozzle 230 and the connection part of the upper end enclosure HW and the side wall SW is 500mm to 1000mm, such as 500mm to 700mm, 600mm to 800mm, or 700mm to 900 mm. Alternatively, the plurality of coal-water slurry nozzles 230 are located at the same height.

In these embodiments, the coal-water slurry nozzles 230 are preferably arranged obliquely with respect to the central axis of the combustion chamber 210. Further, the inclination angle is 60 to 90 degrees, for example, 60 to 75 degrees, 65 to 80 degrees, or 70 to 85 degrees. The inclination angle of the water-coal-slurry nozzle 230 is within a proper range, and the water-coal-slurry and oxygen have vertical downward component velocities, so that the flow direction of the mixed water-coal-slurry and oxygen is consistent with the final flow direction of the fluid in the furnace, which is beneficial to being distributed to the whole section of the combustion chamber 210 and improves the process efficiency of the water-coal-slurry gasification furnace 200. And, the inclination angle of the water-coal-slurry nozzle 230 is suitable for ensuring that the mixed fluid has enough residence time in the furnace, thereby ensuring the full reaction.

By reasonably arranging the water-coal-slurry nozzle 230, the water-coal-slurry, oxygen and the crude synthesis gas can be fully mixed, and the whole mixed fluid vertically flows downwards to perform full chemical reaction, so that the content of phenol, tar and aliphatic hydrocarbon in the obtained synthesis gas is low, and the components of the synthesis gas are stable.

In some embodiments, there are an even number of coal-water slurry nozzles 230, such as 2, 4, etc. Every two coal-water slurry nozzles 230 are symmetrically arranged on two sides of the raw synthesis gas inlet 220 along the radial direction of the coal-water slurry gasification furnace. The coal-water slurry nozzles 230 are symmetrically arranged, the central axes thereof meet at the same point, and the intersection point is located on the central axis of the coal-water slurry gasification furnace 200. Therefore, the central axes of the outlets of all the coal-water slurry nozzles 230 and the communicating pipe 300 are intersected at the same point on the central axis of the coal-water slurry gasification furnace 200, so that the coal-water slurry, the oxygen and the synthesis gas can be more fully collided and mixed, a sufficient chemical reaction can be carried out, and the reaction efficiency can be improved. This facilitates the increase of the available gas (CO + H)₂) The gas production rate of (2) and reduce phenol, tar and CH₄And the like. PreferablyAnd the water-coal-slurry nozzle 230 is arranged at the top of the water-coal-slurry gasification furnace 200. Thus, the coal water slurry, the oxygen and the synthesis gas fed into the coal water slurry gasification furnace 200 can be more fully collided and mixed, a better flow field is formed, the gas production rate of the effective gas is further improved, and the phenol, the tar and the CH are further reduced₄And the like.

In some embodiments, the bottom of the coal-water slurry gasification furnace 200 is provided with a slag water outlet 240. The coal-water slurry gasification furnace 200 is also internally provided with a chilling chamber 250 positioned between the combustion chamber 210 and the slag water outlet 240, and the combustion chamber 210 is communicated with the chilling chamber 250 through a slag hole. The slag notch is typically provided with a downcomer 260 extending from the slag notch in the direction of the slag water outlet 240. The synthesis gas outlet 270 of the coal-water slurry gasification furnace 200 is arranged on the furnace body side wall SW and is communicated with the chilling chamber 250, and is positioned in the area, close to the combustion chamber 210, of the corresponding chilling chamber 250. The synthesis gas and the slag generated by the combustion chamber 210 enter the chilling chamber 250 through the down pipe 260, chilling water is contained in the chilling chamber 250, and the synthesis gas and the slag are cooled by the chilling water and separated in the chilling chamber 250. The synthesis gas is then sent out of the coal water slurry gasification furnace 200 through the synthesis gas outlet 270, and the cooled and solidified slag and slag water are discharged out of the coal water slurry gasification furnace 200 through the slag water outlet 240.

In some embodiments, the communication pipe 300 includes an inner pipe shell 310 and an outer pipe shell 320 sleeved outside the inner pipe shell 310, and the first heat exchange interlayer 330 is formed between the inner pipe shell 310 and the outer pipe shell 320 at intervals. By introducing a cooling medium such as water into the first heat exchange interlayer 330, the communication pipe 300 can be cooled and protected.

In some embodiments, a portion of the furnace wall FW of the coal-water slurry gasification furnace, which corresponds to the combustion chamber 210, includes an inner wall FW1 and an outer wall FW2 sleeved outside the inner wall FW1, and a second heat exchange interlayer FW3 is formed between the inner wall FW1 and the outer wall FW2 at intervals. By introducing a cooling medium such as water into the second heat exchange sandwich FW3, the furnace wall FW can be cooled and protected. Further, the inner wall FW1 is made of a refractory material such as firebrick. Thus, the coal-water slurry gasification furnace 200 has a longer service life. The inner wall FW1 made of refractory materials and the inner wall FW1 and the outer wall FW2 form a heat exchange sandwich structure, so that the heat insulation effect of the furnace wall FW is better, the process temperature in the furnace can be higher, the gasification conversion of methane, phenol and tar in the crude synthesis gas is facilitated, the contents of methane, phenol and tar can be reduced, and the quality of the synthesis gas is improved.

In some embodiments, second heat exchange interlayer FW3 is in communication with first heat exchange interlayer 330. This can reduce the number of cooling medium inlet and outlet pipes and simplify the structure of the device. As an example, the cooling medium inlet I may be located at a bottom end of a portion of the furnace wall FW of the coal-water slurry gasifier corresponding to the combustion chamber 210, and the cooling medium outlet O may be located in a region of the communicating tube 300 near the fixed-bed gasifier 100. And the cooling medium enters the heat exchange interlayer from the cooling medium inlet I for heat exchange and is discharged from the cooling medium outlet O.

In some embodiments, the communicating tube 300 is further optionally provided with a flow regulating device (not shown in the figure). The flow of the raw synthesis gas entering the water coal slurry gasifier 200 is conveniently adjusted by the flow adjusting device.

Referring to fig. 2, in some embodiments, the system further includes a wash unit 400. The washing unit 400 is used for cooling and dedusting the synthesis gas sent out by the coal water slurry gasification furnace 200. As an example, the washing unit 400 may include a venturi scrubber 410 connected to the syngas outlet 270 of the coal-water slurry gasification furnace 200, and a washing tower 420 connected to a gas outlet of the venturi scrubber 410. The venturi scrubber 410 may dust and cool the syngas. The scrubber 420 may provide fine dust removal and further cooling of the syngas. The scrubber 420 may be a packed scrubber, a spray tower, or the like.

The scrubbing liquid of the venturi scrubber 410 and the scrubbing tower 420 can be selected as desired. As an example, the scrubbing liquid of the venturi scrubber 410 and the scrubbing tower 420 can both be water.

Because phenol, tar and CH in the synthesis gas sent out by the coal water slurry gasification furnace 200₄And the content of the washing water is low, so that the water quality of the washing water washed by the washing unit 400 is simple, the washing water can be recycled, and the wastewater discharge is greatly reduced. In some embodiments, the wash unit 400 further comprises a bottoms outlet connected to the wash column 420 anda solid-liquid separation device 430 and a circulation pump 440 between the inlets for the overhead scrubbing liquid. The solid-liquid separation equipment 430 performs solid-liquid separation treatment on the tower bottoms to obtain a washing liquid. The solid-liquid separation device 430 may be a settling tank. The washing liquid returns to the washing tower 420 through the circulation pump 440, realizing recycling.

In some embodiments, the bottom outlet of the washing tower 420 is connected to a chilled water inlet (not shown) of the coal-water slurry gasifier 200. At least a part of the bottom liquid of the washing tower 420 may be used for chilling water of the coal-water slurry gasification furnace 200.

In some embodiments, the liquid outlet of the venturi scrubber 410 is connected to the chilled water inlet of the coal-water slurry gasifier 200. At least a portion of the bottoms of the venturi scrubber 410 may be used for chilling water of the coal-water slurry gasifier 200.

In some embodiments, the washing water after washing by the washing unit 400 may also be used to make the coal water slurry.

Although not shown in the drawings, the coal gasification conversion system of the present invention may optionally further include a coal feeding unit, a slag discharging unit, a gasifying agent supply unit, a cooling medium circulation unit, and the like. The coal charging unit, the slag discharging unit, the gasifying agent supply unit, and the cooling medium circulating unit may respectively include related devices known in the art.

Next, a coal gasification conversion process is provided. The coal gasification conversion method can be implemented by adopting the coal gasification conversion system. The method comprises a fixed bed gasification step and a coal water slurry gasification step.

The fixed bed gasification step comprises the step of performing pressure gasification on the raw material coal in a fixed bed gasification furnace by using oxygen-containing gas and water vapor as gasification agents to generate crude synthesis gas.

The fixed bed gasification furnace usually adopts lump coal as raw material, and reacts with a gasification agent under pressurization to prepare synthesis gas, and has the advantage of wide raw material adaptability. For example, the raw material coal may be selected from anthracite, bituminous coal, lignite, and the like. In a fixed bed gasification furnace, raw material coal is added from a feed inlet at the top of the furnace, and after the raw material coal passes through five areas of a drying area, a dry distillation area, a gasification area, a combustion area and a slag area (slag area) downwards in sequence, the residual slag (slag) after reaction is discharged from the bottom of the furnaceAnd discharging from a slag discharge port. The gasifying agent is added into the combustion zone from a gasifying agent nozzle to participate in the gasification reaction. The gas in the furnace moves from bottom to top, and the sensible heat of the gas can be fully utilized. Finally, the raw synthesis gas is sent out from a gas outlet. The main components of the crude synthesis gas are CO and H₂、CO₂And entrains more phenol, tar and aliphatic hydrocarbon (such as CH) generated in the dry distillation zone₄) And the like.

In some embodiments, the oxygen-containing gas is oxygen in a fixed bed gasification step. Further, if the fixed bed gasification furnace is a solid-state slag discharge gasification furnace, the mass-to-volume ratio of water vapor to oxygen in the gasification agent may be 3kg/Nm³～7kg/Nm³Or 4kg/Nm³～6kg/Nm³. If the fixed bed gasification furnace is a slag tapping gasification furnace, the mass volume ratio of water vapor and oxygen in the gasification agent can be 0.7kg/Nm³～1.2kg/Nm³Or 0.9kg/Nm³～1.1kg/Nm³. The mass to volume ratio of water vapor and oxygen refers to the mass of water vapor in kg to oxygen in Nm³Volume ratio in kg/Nm³。Nm³Is a standard cubic meter and represents the amount of gas in 1 cubic meter at a pressure of one standard atmosphere (101.325kPa), a temperature of 0 c, and a relative humidity of 0%. The proportion of the water vapor and the oxygen in the gasifying agent is in a proper range, which is beneficial to improving the reaction temperature of a gasification zone, thereby improving the effective gas (CO + H)₂) The gas production rate.

In some embodiments, the temperature of the retort zone can be from 300 ℃ to 800 ℃. In the dry distillation area, the raw material coal is subjected to low-temperature dry distillation, and the generated dry distillation coal gas mainly comprises CH₄、H₂CO, and phenol, tar, and the like. The temperature of the gasification zone is greater than 800 ℃, for example greater than 800 ℃ and less than or equal to 1400 ℃. The temperature of the gasification zone is high, and the main components of the obtained coal gas in the zone are CO and CO₂、H₂And H₂O, and the content of the effective gas is higher.

The step of gasifying the coal water slurry comprises the steps of introducing the crude synthesis gas into a combustion chamber of the coal water slurry gasification furnace from the top of the coal water slurry gasification furnace, spraying oxygen and the coal water slurry into the combustion chamber from a coal water slurry nozzle, and pressurizing and gasifying the crude synthesis gas and the coal water slurry in the combustion chamber to obtain a synthesis gas product.

The water-coal-slurry gasification furnace belongs to one kind of entrained flow bed gasification, and has the advantages of less impurities in the produced synthesis gas and the like. The raw synthesis gas from the fixed bed gasification furnace is fed into the furnace from the top of the furnace, the coal water slurry and oxygen are sprayed into the furnace through the coal water slurry nozzle, and are fully mixed and undergo a series of chemical reactions under the pressurization condition to generate synthesis gas. The content of effective gas in the synthesis gas generated by the coal water slurry gasification furnace is high, phenol, tar and CH₄The content of iso is very low and the composition of the synthesis gas is stable.

The coal water slurry can be prepared from coal powder and water. Optionally, the mass percentage concentration of the raw material coal in the coal water slurry is 50-60%. The water for preparing the coal water slurry can also utilize industrial organic wastewater and saline wastewater. This is beneficial to alleviating the problem of enterprise wastewater treatment. The gasification of coal water slurry has certain requirements on coal types. The raw material coal of the coal water slurry gasification furnace can be selected from coal types such as bituminous coal, lignite and the like. Anthracite coal may also be selected without regard to production costs.

The utility model discloses a coal gasification conversion method can obtain high-quality synthetic gas product through the advantage complementation with fixed bed gasifier and coal slurry gasifier to can simplify follow-up waste water treatment process, effectively alleviate the waste water treatment difficult problem. CH in syngas₄Low content, and can reduce the purge gas amount and energy consumption of the ammonia synthesis system when used as the raw material gas of the ammonia synthesis system.

In some embodiments, the amount of oxygen added to the coal-water slurry gasification furnace satisfies the following conditions: the ratio of the mass of coal in the coal water slurry to the volume of oxygen is 0.7kg/Nm³～0.8kg/Nm³. The amount of oxygen added into the coal water slurry gasification furnace is proper, which is beneficial to improving the gas production rate of effective gas and reducing phenol, tar and CH₄And the like.

In some embodiments, the mass to volume ratio of the coal-water slurry to the raw syngas is 0.8kg/Nm³～0.9kg/Nm³. The ratio of the coal water slurry to the crude synthesis gas is proper, which is beneficial to improving the gas yield of the effective gas and reducing phenol, tar and CH₄And the like.

In some embodiments, in the step of gasifying the coal water slurry, the reaction temperature in the coal water slurry gasifier is 1100 ℃ to 1300 ℃, or 1200 ℃ to 1300 ℃.

In some embodiments, the pressure of the pressurized gasification in the fixed bed gasification step is greater than the pressure of the pressurized gasification in the coal water slurry gasification step. Therefore, the crude synthesis gas generated by the fixed bed gasification furnace can flow to the water-coal-slurry gasification furnace conveniently, high-temperature gas in the water-coal-slurry gasification furnace can be prevented from flowing back to the fixed bed gasification furnace, the system is ensured to operate stably, and equipment is prevented from being damaged.

In some embodiments, the fixed bed gasification step is conducted at a pressure of 2.5MPa to 6.5MPa, such as 2.5MPa to 4MPa, 3.5MPa to 4.5MPa, or 3MPa to 5 MPa.

In some embodiments, the pressure at which the pressure gasification is carried out in the coal water slurry gasification step is from 2MPa to 4MPa, such as from 2MPa to 3MPa, or from 2.5MPa to 3.5 MPa.

Herein, the coal gasification conversion process may be performed using a coal gasification conversion system. Furthermore, the technical features described herein for a coal gasification conversion system may also be applied to the coal gasification conversion process of the present invention.

The synthesis gas produced by the coal gasification conversion system and the method of the utility model can be used as chemical raw material gas, industrial coal gas, fuel gas and the like. In some embodiments, syngas may be used as a feed gas for the synthesis of ammonia. Due to CH in the synthesis gas₄The content is reduced, thereby being beneficial to reducing the purge gas amount and the energy consumption of the ammonia synthesis system.

The utility model provides a coal gasification synthetic ammonia system. FIG. 3 is a flow diagram of a coal gasification ammonia synthesis system as one example. Referring to fig. 3, a coal gasification ammonia synthesis system according to an embodiment of the present invention includes a gas making unit 1, a shift unit 2, a decarbonization unit 3, a double-shell refining unit 4, and an ammonia synthesis unit 5.

The gas making unit 1 comprises a coal gasification conversion system provided by the utility model. The gas making unit 1 gasifies the raw material coal to produce synthesis gas. The synthesis gas may be sent directly to the shift unit 2 for shift processing.

Conversion unit 2 and gas-generating unit1 for receiving syngas from the gas-making unit 1 and subjecting the syngas to a shift treatment for converting CO to CO₂And sending out the transformation gas.

The decarbonizing unit 3 is configured to decarbonize the shift gas from the shift unit 2 to obtain a decarbonized gas. Decarbonizing CO in a decarbonized gas₂The content is obviously reduced.

The double refining unit 4 is used for double refining the decarbonized gas from the decarbonization unit 3 to obtain a raw material gas. Refining with methanol or methanation to obtain CO and CO in the decarbonized gas₂And a methyl compound is produced as a byproduct. The content of carbon oxide in the raw material gas reaches the strict requirement of synthetic ammonia by the refining treatment of the dimethyl formamide.

The synthesis ammonia unit 5 is used for receiving the raw material gas from the double-methyl refining unit 4 and synthesizing ammonia by using the raw material gas.

Referring to fig. 4, in some embodiments, if the sulfur content of the syngas from the gas-generating unit 1 is greater than 0.05ppm, the system may further include a shift unit 6 and a desulfurization unit 7. The shift unit 6 and the desulfurization unit 7 are sequentially disposed between the shift unit 2 and the decarburization unit 3, and are used for desulfurizing the synthesis gas.

The shift unit 2, the decarbonization unit 3, the dimethyl refining unit 4, the ammonia synthesis unit 5, the shift unit 6 and the desulfurization unit 7 can adopt the processes and devices known in the art.

The features described herein with respect to the coal gasification conversion process and system of the present invention are also applicable to the coal gasification ammonia synthesis system of the present invention.

In this context, the content of the components in the gas is referred to as volume percentage.

Examples

The following example employs a coal gasification conversion system as shown in FIG. 1.

Example 1

The fixed bed gasification furnace is a solid slag discharge gasification furnace (Lurgi furnace). The raw material coal adopts smokeless lump coal, is added into the fixed bed gasification furnace from a furnace top feed inlet of the furnace through a coal adding unit, and is added into the furnaceUnder the gasification pressure of 4.5MPa, the oxygen vaporizing agent is added into the gasification agent nozzle (the mass volume ratio of the water vapor to the oxygen is 4.7kg/Nm³) Carrying out a series of reactions to generate crude synthesis gas which is discharged from a coal gas outlet. The temperature of the raw synthesis gas is 520 ℃, and the effective gas (CO + H)₂) Content 62.5%, CH₄The content is 9.5 percent, and the content of impurities such as phenol, tar and the like is 0.6 percent. The reacted coal slag is discharged from a slag discharge port as solid slag (ash slag), and can be recycled.

The water-coal-slurry gasification furnace is provided with a combustion chamber at the upper part and a chilling chamber at the lower part, a crude synthesis gas inlet communicated with the combustion chamber is arranged at the middle position of the top of the water-coal-slurry gasification furnace, and the crude synthesis gas inlet is communicated with a coal gas outlet of the fixed bed gasification furnace through a communicating pipe. The two water-coal-slurry nozzles are distributed at the top of the water-coal-slurry gasification furnace along the circumferential direction of the crude synthesis gas inlet and are symmetrically distributed at two sides of the crude synthesis gas inlet along the radial direction of the water-coal-slurry gasification furnace. The water-coal-slurry nozzle is inclined by 30 degrees relative to the central axis of the combustion chamber. Mixing the bituminous coal with the waste water after the coal gas is washed, and preparing the coal water slurry with the coal mass percentage concentration of 60%. The coal water slurry and oxygen are sprayed into the coal water slurry gasification furnace from the coal water slurry nozzle, and simultaneously, the crude synthesis gas from the fixed bed gasification furnace enters the coal water slurry gasification furnace from the top of the furnace through the communicating pipe. The oxygen amount added into the coal water slurry gasification furnace meets the requirement that the ratio of the mass of the coal in the coal water slurry to the volume of the oxygen is 0.8kg/Nm³. The mass volume ratio of the coal water slurry to the crude synthesis gas is 0.8kg/Nm³. Under the conditions of gasification pressure of 4.0MPa and gasification temperature of 1250 ℃, the crude synthesis gas, coal water slurry and oxygen are subjected to a series of reactions in a furnace to generate synthesis gas. In the process, the crude synthesis gas is subjected to secondary gasification, wherein phenol, tar and CH are contained₄And the like are removed by a combustion reaction with oxygen. In addition, organic matter in the wastewater is removed by a combustion reaction with oxygen. The content of effective gas in the obtained synthesis gas is 81.2 percent, and the content of CH₄The total content of phenol and tar impurities is less than 0.5 percent, and the quality of the synthesis gas is greatly improved.

The synthetic gas carries with slag and flows downwards, is discharged from a synthetic gas outlet after being cooled by chilling water, and can be used as chemical raw material gas, industrial coal gas, fuel gas and the like. The slag is discharged from a slag water outlet after quenching, and can be recycled.

The subsequent washing unit washes the synthesis gas, the quality of the generated washing water is simple, the washing water can be recycled or used for pulping, and the wastewater discharge is greatly reduced.

Table 1 shows the composition of the raw synthesis gas discharged from the fixed-bed gasification furnace and the synthesis gas produced from the coal-water slurry gasification furnace according to example 1.

TABLE 1

Gas component	CO	H₂	CO₂	CH₄	H₂S	N₂+Ar	Tar, phenol, etc
								Raw synthesis gas	25.7	36.8	26.2	9.5	0.7	0.5	0.6
Synthesis gas	43.6	37.6	17.9	0.1	0.3	0.4	0.1

Example 2

The fixed bed gasification furnace is a liquid slag discharge gasification furnace (fixed bed slag gasification furnace). The raw material coal is lignite lump coal, is added into the fixed bed gasification furnace from a furnace top feed inlet of the furnace through a coal adding unit, and is mixed with an oxygen steaming oxidant (the mass volume ratio of water vapor to oxygen is 0.96 kg/Nm) added by a gasification agent nozzle under the gasification pressure of 4MPa³) Carrying out a series of reactions to generate crude synthesis gas which is discharged from a coal gas outlet. The temperature of the crude synthesis gas is 350 ℃, and the effective gas (CO + H)₂) Content 70.2%, CH₄The content is 8.5 percent, and the content of impurities such as phenol, tar and the like is 1.2 percent. The reacted coal slag is chilled to form glass state slag as liquid slag (molten slag), and can be recycled.

The water-coal-slurry gasification furnace is provided with a combustion chamber at the upper part and a chilling chamber at the lower part, a crude synthesis gas inlet communicated with the combustion chamber is arranged at the middle position of the top of the water-coal-slurry gasification furnace, and the crude synthesis gas inlet is communicated with a coal gas outlet of the fixed bed gasification furnace through a communicating pipe. The two water-coal-slurry nozzles are distributed at the top of the water-coal-slurry gasification furnace along the circumferential direction of the crude synthesis gas inlet and are symmetrically distributed at two sides of the crude synthesis gas inlet along the radial direction of the water-coal-slurry gasification furnace. The water-coal-slurry nozzle is inclined by 30 degrees relative to the central axis of the combustion chamber. Mixing lignite with the waste water after coal gas washing to prepare coal water slurry with coal mass percentage concentration of 60%. Spraying the coal water slurry and oxygen into the coal water slurry gasification furnace from the coal water slurry nozzle and simultaneously from the fixed bed gasification furnaceThe raw synthesis gas enters the coal water slurry gasification furnace from the furnace top through a communicating pipe. The oxygen amount added into the coal water slurry gasification furnace meets the requirement that the ratio of the mass of the coal in the coal water slurry to the volume of the oxygen is 0.8kg/Nm³. The mass volume ratio of the coal water slurry to the crude synthesis gas is 0.8kg/Nm³. Under the conditions of gasification pressure of 3.0Mpa and gasification temperature of 1200 ℃, the crude synthesis gas, coal water slurry and oxygen are reacted in a furnace to generate synthesis gas. In the process, the crude synthesis gas is subjected to secondary gasification, wherein phenol, tar and CH are contained₄And the like are removed by a combustion reaction with oxygen. In addition, organic matter in the wastewater is removed by a combustion reaction with oxygen. The content of effective gas in the obtained synthesis gas is 82.0 percent, and the content of CH₄The total content of phenol and tar is less than 0.5 percent, and the quality of the synthesis gas is greatly improved.

Table 2 shows the composition of the raw synthesis gas discharged from the fixed-bed gasification furnace and the synthesis gas produced from the coal-water slurry gasification furnace according to example 2.

TABLE 2

Gas component	CO	H₂	CO₂	CH₄	H₂S	N₂+Ar	Tar, phenol, etc
								Raw synthesis gas	40.2	30.0	17.6	8.5	0.4	2.1	1.2
Synthesis gas	43.9	38.1	16.9	0.1	0.1	0.6	0.3

Example 3

The fixed bed gasification furnace is a liquid slag discharge gasification furnace. The raw material coal is lignite lump coal, is added into the fixed bed gasification furnace from a furnace top feed inlet of the furnace through a coal adding unit, and is mixed with an oxygen steaming oxidant (the mass volume ratio of water vapor to oxygen is 0.96 kg/Nm) added by a gasification agent nozzle under the gasification pressure of 4MPa³) Carrying out a series of reactions to generate crude synthesis gas which is discharged from a coal gas outlet. The temperature of the crude synthesis gas is 350 ℃, and the effective gas (CO + H)₂) Content 70.2%, CH₄The content is 8.5 percent, and the content of impurities such as phenol, tar and the like is 1.2 percent. The reacted coal slag is chilled to form glass state slag as liquid slag (molten slag), and can be recycled.

The water-coal-slurry gasification furnace is provided with a combustion chamber at the upper part and a chilling chamber at the lower part, a crude synthesis gas inlet communicated with the combustion chamber is arranged at the middle position of the top of the water-coal-slurry gasification furnace, and the crude synthesis gas inlet is communicated with a coal gas outlet of the fixed bed gasification furnace through a communicating pipe. Two slurriesThe nozzles are distributed on the side wall along the circumferential direction of the side wall of the water-coal-slurry gasification furnace, and are symmetrically arranged on two sides of the crude synthesis gas inlet along the radial direction of the water-coal-slurry gasification furnace, and the distance between the water-coal-slurry nozzles and the connection part of the upper end enclosure and the side wall is 600 mm. The water-coal-slurry nozzle is inclined at 75 degrees relative to the central axis of the combustion chamber. Mixing lignite with the waste water after coal gas washing to prepare coal water slurry with coal mass percentage concentration of 60%. The coal water slurry and oxygen are sprayed into the coal water slurry gasification furnace from the coal water slurry nozzle, and simultaneously, the crude synthesis gas from the fixed bed gasification furnace enters the coal water slurry gasification furnace from the top of the furnace through the communicating pipe. The oxygen amount added into the coal water slurry gasification furnace meets the requirement that the ratio of the mass of the coal in the coal water slurry to the volume of the oxygen is 0.8kg/Nm³. The mass volume ratio of the coal water slurry to the crude synthesis gas is 0.8kg/Nm³. Under the conditions of gasification pressure of 3.0Mpa and gasification temperature of 1200 ℃, the crude synthesis gas, coal water slurry and oxygen are reacted in a furnace to generate synthesis gas. In the process, the crude synthesis gas is subjected to secondary gasification, wherein phenol, tar and CH are contained₄And the like are removed by a combustion reaction with oxygen. In addition, organic matter in the wastewater is removed by a combustion reaction with oxygen. The content of effective gas in the obtained synthetic gas is 79.5 percent, and the content of CH₄The total content of phenol and tar is less than 1 percent, and the quality of the synthesis gas is greatly improved.

Table 3 shows the composition of the raw synthesis gas discharged from the fixed-bed gasification furnace and the synthesis gas produced from the coal-water slurry gasification furnace according to example 3.

TABLE 3

Gas component	CO	H₂	CO₂	CH₄	H₂S	N₂+Ar	Tar, phenol, etc
								Raw synthesis gas	40.2	30.0	17.6	8.5	0.4	2.1	1.2
Synthesis gas	42.4	37.1	18.9	0.3	0.1	0.8	0.4

From the above results, it can be seen that a high-quality syngas product can be obtained by using the coal gasification conversion system and method of the present invention. The content of phenol, tar, aliphatic hydrocarbon and the like in the synthesis gas is reduced, and the problem of wastewater treatment can be effectively relieved.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of various equivalent modifications or replacements within the technical scope of the present invention, and these modifications or replacements should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A coal gasification conversion system, comprising:

the coal water slurry gasification furnace is provided with a combustion chamber, a crude synthesis gas inlet communicated with the combustion chamber and a coal water slurry nozzle communicated with the combustion chamber, wherein the crude synthesis gas inlet is positioned at the top of the coal water slurry gasification furnace and is connected with an outlet of the communicating pipe, and the coal water slurry gasification furnace carries out secondary gasification on the crude synthesis gas to obtain synthesis gas.

2. The system of claim 1, wherein the raw syngas inlet is located at a middle position of the top of the coal-water slurry gasification furnace;

and the plurality of water-coal-slurry nozzles are distributed at the top of the water-coal-slurry gasification furnace along the circumferential direction of the crude synthesis gas inlet.

3. The system of claim 2, wherein the coal-water slurry nozzle is disposed at an angle of 15-45 degrees with respect to a central axis of the combustion chamber.

4. The system of claim 1, wherein the coal water slurry gasification furnace comprises a side wall and an upper end enclosure connected to the top end of the side wall, the coal water slurry nozzles are distributed on the side wall along the circumferential direction of the side wall, and the distance between the coal water slurry nozzles and the connection position of the upper end enclosure and the side wall is 500-1000 mm.

5. The system of claim 4, wherein the coal-water slurry nozzle is arranged obliquely with respect to the central axis of the combustion chamber at an angle of 60-90 degrees.

6. The system according to any one of claims 2 to 5, wherein the number of the coal-water slurry nozzles is even, and every two coal-water slurry nozzles are symmetrically arranged on two sides of the raw synthesis gas inlet along the radial direction of the coal-water slurry gasification furnace.

7. The system of claim 1, wherein the communication pipe comprises an inner pipe shell and an outer pipe shell sleeved outside the inner pipe shell, and a first heat exchange interlayer is formed between the inner pipe shell and the outer pipe shell at intervals;

the part of the furnace wall of the coal water slurry gasification furnace, which corresponds to the combustion chamber, comprises an inner wall and an outer wall sleeved outside the inner wall, a second heat exchange interlayer is formed between the inner wall and the outer wall at intervals, and the second heat exchange interlayer is communicated with the first heat exchange interlayer.

8. The system of claim 1, wherein the communicating tube is provided with a flow regulating device.

9. The system of claim 1, further comprising:

the Venturi scrubber is connected with a synthesis gas outlet of the coal water slurry gasification furnace;

a scrubber tower connected to the gas outlet of the venturi scrubber; and

and the solid-liquid separation equipment and the circulating pump are arranged between the tower bottom liquid outlet and the tower top washing liquid inlet of the washing tower.

10. The system of claim 9, wherein a slag water outlet is arranged at the bottom of the coal water slurry gasification furnace, a chilling chamber is arranged in the coal water slurry gasification furnace and is positioned between the combustion chamber and the slag water outlet, and the combustion chamber is communicated with the chilling chamber through a slag hole; and

a tower bottom liquid outlet of the washing tower is connected with a chilling water inlet of the coal water slurry gasification furnace; and/or the liquid outlet of the Venturi scrubber is connected with the chilling water inlet of the coal water slurry gasification furnace.

11. The system of claim 1, wherein the fixed bed gasifier is a solid-state or liquid-state slagging gasifier.

12. A coal gasification ammonia synthesis system comprising the coal gasification conversion system according to any one of claims 1 to 11.