A process and system for pyrolysis and co-gasification of water-coal slurry and solid waste

Abstract

A process and system for pyrolysis and co-gasification of water-coal slurry and solid waste, comprising the following steps: S1, dehydrating and drying the solid waste to obtain dry water vapor and dry solid waste; S2, pyrolyzing the dry solid waste to obtain low-temperature water vapor, semi-coke, pyrolysis gas and tar, and then crushing the semi-coke to obtain semi-coke powder; S3, cooling the dry water vapor to obtain cooling water, and grinding the raw coal and mixing it with the cooling water to obtain water-coal slurry; S4, mixing the semi-coke powder, pyrolysis gas, tar and water-coal slurry and then adding oxygen for gasification to obtain crude synthesis gas; S5, cooling the crude synthesis gas to obtain synthesis gas and high-temperature and high-pressure water vapor; the high-temperature and high-pressure water vapor provides heat for the pyrolysis of S2. The semi-coke powder obtained by drying, pyrolyzing and crushing the solid waste replaces part of the raw coal to prepare synthesis gas, which saves coal resources while reducing and recycling part of the solid waste, saving 22% of the raw coal and 2% of the oxygen, and increasing the total amount of synthesis gas obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of coal pyrolysis and gasification, and specifically relates to a pyrolysis and co-gasification process and system for water-coal slurry and solid waste. Background Art

[0002] Large-scale coal gasification technology is a mature, environmentally friendly and widely used clean coal technology. It is a leading technology in coal chemical industry and the basis for the development of coal-based chemical synthesis (ammonia, methanol, acetic acid, olefins, etc.), liquid fuel synthesis (dimethyl ether, gasoline, diesel, etc.), advanced IGCC power generation systems, cogeneration systems, hydrogen production, fuel cells, direct reduction ironmaking and other process industries. It is a public technology, key technology and leading technology in these industries.

[0003] According to the different feeding methods, the entrained-bed coal gasification process can be divided into dry gasification (dry pulverized coal feeding) and wet gasification (water-coal slurry feeding). Wet gasification (water-coal slurry feeding) is a relatively mature pressurized gasification technology in the entrained-bed technology. It has the advantages of a wide range of adaptability of raw coal, good quality of synthesis gas, high effective gas composition, simple process flow, large production capacity, and low environmental pollution. However, the water-coal slurry coal gasification technology has strict requirements on the slurryability of coal types, high oxygen consumption, low cold gas efficiency, and strict requirements on equipment materials, especially nozzles and refractory bricks; while dry gasification (dry pulverized coal feeding) has advanced technical indicators, strong adaptability to coal types, and O 2 The process has the advantages of low coal consumption, high effective gas content, no three wastes pollution, and long burner service life (guaranteed for 1 year). However, the process uses a waste heat boiler with a membrane wall, a high-temperature and high-pressure ceramic filter, a quenching circulator compressor, and a relatively complex structure of key gasification equipment, as well as a long manufacturing cycle, resulting in high equipment cost, high investment, and a long project construction period. The raw coal grinding, nitrogen pressurization, and recycled synthesis gas pressurization require relatively large power consumption, and the initial investment is too high, so there are few industrial operation devices. Summary of the invention

[0004] In view of the above problems, the purpose of the present invention is to provide a process and system for the pyrolysis and co-gasification of water-coal slurry and solid waste, in which semi-coke powder obtained by drying, pyrolyzing and crushing solid waste replaces part of the raw coal to prepare synthesis gas, which saves coal resources and reduces and recycles part of the solid waste; and the cooling water obtained by drying the solid waste is mixed with the ground raw coal to prepare water-coal slurry, saving a large amount of water resources; at the same time, the heat required for the pyrolysis of solid waste is provided by the high-temperature and high-pressure water vapor obtained by cooling the crude synthesis gas, which can be recycled and only needs a small amount of supplement when it is insufficient, thus saving energy as a whole; for the production of a certain amount of synthesis gas, the process of the present invention saves 22% of the raw coal and 2% of the oxygen, improves the utilization efficiency of water in the water-coal slurry, reduces the content of water vapor in the crude synthesis gas, increases the total amount of synthesis gas produced, and increases the cold gas efficiency from 72% to 74%, and the specific oxygen consumption from 568Nm~600Nm 3 / kNm 3 Reduced to ~556Nm 3 / kNm 3 .

[0005] To achieve the above object, the technical solution adopted by the present invention includes:

[0006] A pyrolysis and co-gasification process of water-coal slurry and solid waste comprises the following steps:

[0007] S1, dehydrating and drying the solid waste to obtain dry water vapor and dry solid waste;

[0008] S2, pyrolyzing the dry solid waste obtained in S1 to obtain low-temperature water vapor, semi-coke, pyrolysis gas and tar, and then crushing the semi-coke to obtain semi-coke powder; wherein the low-temperature water vapor is circulated to S1 and used for dehydration and drying of the solid waste;

[0009] S3, cooling the dry water vapor obtained in S1 to obtain cooling water, and grinding the raw coal and mixing it with the cooling water to obtain a water-coal slurry;

[0010] S4, mixing the semi-coke powder, pyrolysis gas and tar obtained in S2 and the water-coal slurry obtained in S3, and then adding oxygen for gasification to obtain a crude synthesis gas;

[0011] S5, cooling the crude synthesis gas obtained in S4 to obtain synthesis gas and high-temperature and high-pressure steam; the high-temperature and high-pressure steam provides heat for the thermal decomposition of S2.

[0012] Preferably, the mass ratio of dried solid waste: raw coal: oxygen is (0.6-1.3):1:(1-1.4); the moisture content of the solid waste is 50-80%, and the moisture content of the solid waste after drying is 5-10%.

[0013] Preferably, the dehydration and drying temperature of the solid waste in S1 is 105-120°C, and the temperature of the drying and water vapor produced by S1 is 115-120°C.

[0014] Preferably, the pyrolysis temperature of the dry solid waste in S2 is 350-400°C, and the pyrolysis time is 30min±5min.

[0015] Preferably, the concentration of the water-coal slurry obtained in S3 is 60-70%.

[0016] Preferably, the gasification temperature of S4 is 1300-1400°C.

[0017] Preferably, the high-temperature and high-pressure steam obtained in S5 has a temperature of 500 to 550° C. and a pressure of 9 to 9.8 MPa.

[0018] Preferably, the particle size of the semi-coke powder is 150-200 mesh.

[0019] A water-coal slurry and solid waste pyrolysis co-gasification system, according to the process disclosed in the present invention, comprises a solid waste drying pyrolysis mechanism, a water-coal slurry preparation mechanism, a crude synthesis gas preparation mechanism and a synthesis gas preparation circulation mechanism;

[0020] The solid waste drying and pyrolysis mechanism is used for dehydration, drying and pyrolysis of solid waste. The solid waste is dehydrated and dried to obtain dry water vapor and dry solid waste. The dry solid waste is pyrolyzed to obtain low-temperature water vapor, semi-coke, pyrolysis gas and tar. The semi-coke is then crushed to obtain semi-coke powder. The warm water vapor is circulated for dehydration and drying of the solid waste.

[0021] The water-coal slurry preparation mechanism is used to cool the dry water vapor obtained by dehydrating and drying the solid waste into cooling water, and grind the raw coal and mix it with the cooling water to obtain water-coal slurry;

[0022] The crude synthesis gas preparation mechanism is used to mix semi-coke powder, pyrolysis gas, tar and water-coal slurry and then add oxygen for gasification to obtain crude synthesis gas;

[0023] The synthesis gas preparation circulation mechanism is used to cool the raw synthesis gas output by the synthesis gas preparation mechanism to obtain synthesis gas and high-temperature and high-pressure water vapor, and the high-temperature and high-pressure water vapor provides heat to the pyrolysis cycle of the drying pyrolysis mechanism.

[0024] Preferably, the drying pyrolysis mechanism includes a drying pyrolysis furnace and a crusher, and the semi-coke discharge port of the drying pyrolysis furnace is connected to the input end of the crusher; the water-coal slurry preparation mechanism includes a first cooler and a pulverizer, the input end of the first cooler is connected to the drying water vapor outlet of the drying pyrolysis furnace, and the output end of the first cooler is connected to the input end of the pulverizer; the crude synthesis gas preparation mechanism includes a gasifier, and the input end of the gasifier is respectively connected to the pyrolysis gas outlet of the drying pyrolysis furnace, the output end of the crusher and the output end of the pulverizer; the synthesis gas preparation circulation mechanism includes a second cooler, the input end of the second cooler is connected to the output end of the gasifier, and the water vapor output end of the second cooler is connected to the drying pyrolysis furnace.

[0025] Compared with the prior art, the advantages of the present invention are:

[0026] (1) The water-coal slurry and solid waste pyrolysis co-gasification process and system of the present invention uses semi-coke powder obtained by drying, pyrolyzing and crushing solid waste to replace part of the raw coal to prepare synthesis gas, thereby saving coal resources and reducing and reusing part of the solid waste. The cooling water obtained by drying the solid waste is mixed with the ground raw coal to prepare water-coal slurry, saving a large amount of water resources. At the same time, the heat required for the pyrolysis of the solid waste is provided by the high-temperature and high-pressure water vapor obtained by cooling the crude synthesis gas, which can be recycled and only needs to be supplemented in small amounts when it is insufficient, thereby saving energy overall.

[0027] (2) The water-coal slurry and solid waste pyrolysis co-gasification process of the present invention sets the mass ratio of dry solid waste: raw coal: oxygen. For the production of a certain amount of synthesis gas, the process of the present invention can save 22% of raw coal and 2% of oxygen compared with the gasification process using only raw coal.

[0028] (3) Compared with the gasification process using only raw coal, the process of the present invention for pyrolysis and co-gasification of water-coal slurry and solid waste has an increased CO content in the synthesis gas, while the ratio of other components does not change significantly, thus meeting the demand for synthesis gas. At the same time, due to the addition of semi-coke powder in the process of the present invention, the utilization efficiency of water in the water-coal slurry is improved, the content of water vapor in the crude synthesis gas is reduced, the total amount of synthesis gas produced is increased, the cold gas efficiency is increased from 72% to 74%, and the specific oxygen consumption is increased from 568Nm~60. 3 / kNm 3 Reduced to ~556Nm 3 / kNm 3 . BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention, but do not constitute a limitation of the present invention. In the accompanying drawings:

[0030] Figure 1It is a schematic diagram of the process flow of pyrolysis and co-gasification of water-coal slurry and solid waste of the present invention;

[0031] Figure 2 It is a structural schematic diagram of the water-coal slurry and solid waste pyrolysis and co-gasification system of the present invention;

[0032] The meaning of each symbol in the accompanying drawings:

[0033] 1 pyrolysis furnace; 2 first cooler; 3 coal mill; 4 crusher; 5 gasification furnace; 6 second cooler. DETAILED DESCRIPTION

[0034] The present invention will be further described in detail below in conjunction with the accompanying drawings, which are intended to explain the present invention rather than to limit it.

[0035] The components of the synthesis gas prepared by the present invention are CO and H 2 Mainly, and contains a small amount of CH 4 , CO 2 The contents of the main components are: 2 The molar percentage of is 31% ± 2%, the molar percentage of CO is 51% ± 2%, and the molar percentage of CH 4 The molar percentage of CO is 0.005% ± 0.0002%, 2 The mole percentage is 16%±1%.

[0036] The solid waste in the present invention is solid waste with high water content, which can be selected from Chinese medicine residues, papermaking black liquor, urban domestic garbage, etc., and the water content is greater than 50%.

[0037] The composition of the crude synthesis gas in the process of the present invention is H 2 O, CO, and H 2 Mainly, and contains a small amount of CH 4 , CO 2 The contents of the main components are: 2 The molar percentage of O is 23% ± 2%, and the molar percentage of H 2 The molar percentage of CO is 24% ± 2%, the molar percentage of CH 4 The molar percentage of CO is 0.004% ± 0.0002%, 2 The mole percentage is 12%±1%.

[0038] The pyrolysis gas in the process of the present invention is mainly composed of H 2 ,CO,CO 2 and CH 4 composition.

[0039] The equipment used in each device of the system of the present invention is all existing equipment. Among them, the pyrolysis furnace 1 is preferably a steam coil heating and trolley feeding structure, the maximum operating temperature of the tank is 500-550°C, the maximum operating pressure is ~2MPa, the maximum operating temperature of the heating coil is 550-600°C, the maximum operating pressure is ~10MPa, and it adopts an internal insulation and fast opening door structure, and the temperature measurement and control points are 10-25 points; the gasification furnace 5 is preferably a Texaco water-coal slurry gasification furnace, a multi-material slurry gasification furnace or a Jinhua furnace, the maximum operating temperature is 1100-1450°C, the maximum operating pressure is ~7MPa, and it adopts a water-cooled wall structure.

[0040] Example 1

[0041] A pyrolysis and co-gasification process of a water-coal slurry and solid waste in this embodiment includes the following steps:

[0042] S1, dehydrating and drying the solid waste to obtain dry water vapor and dry solid waste;

[0043] S2, pyrolyzing the dry solid waste obtained in S1 to obtain low-temperature water vapor, semi-coke, pyrolysis gas and tar, and then crushing the semi-coke to obtain semi-coke powder; wherein the low-temperature water vapor is circulated to S1 and used for dehydration and drying of the solid waste;

[0044] S3, cooling the dry water vapor obtained in S1 to obtain cooling water, and grinding the raw coal and mixing it with the cooling water to obtain a water-coal slurry;

[0045] S4, mixing the semi-coke powder, pyrolysis gas and tar obtained in S2 and the water-coal slurry obtained in S3, and then adding oxygen for gasification to obtain a crude synthesis gas;

[0046] S5, cooling the crude synthesis gas obtained in S4 to obtain synthesis gas and high-temperature and high-pressure steam; the high-temperature and high-pressure steam provides heat for the pyrolysis of S2;

[0047] Its functions are as follows: the present invention uses semi-coke powder obtained by drying, pyrolyzing and crushing solid waste to replace part of the raw coal to prepare synthesis gas, which saves coal resources and can reduce and recycle part of the solid waste; and the cooling water obtained by drying the solid waste is mixed with the ground raw coal to prepare water-coal slurry, saving a large amount of water resources; at the same time, the heat required for the pyrolysis of S1 and S2 solid wastes is provided by the high-temperature and high-pressure water vapor obtained by cooling the crude synthesis gas in S5, which can be recycled and only needs a small amount of supplement when it is insufficient, thus saving energy as a whole.

[0048] Specifically, the mass ratio of dried solid waste: raw coal: oxygen is (0.6-1.3):1:(1-1.4); the moisture content of the solid waste is 50-80%, and the moisture content of the solid waste after drying is 5-10%.

[0049] Its function is: by setting the mass ratio of dry solid waste: raw coal: oxygen, the process of the present invention can save 22% of raw coal and 2% of oxygen compared with the gasification process using only raw coal; compared with the gasification process using only raw coal, the content of CO in the generated synthesis gas of the present invention is increased, and the proportion of other components does not change significantly, thus meeting the demand for synthesis gas.

[0050] The dry solid waste in this embodiment is Chinese medicinal slag with a moisture content of 63.68%, and the raw coal is lignite.

[0051] Specifically, the dehydration and drying temperature of the solid waste in S1 is 105-120°C, preferably 120°C; the temperature of the drying and water vapor produced by S1 is 115-120°C, preferably 120°C.

[0052] Specifically, the pyrolysis temperature of the dry solid waste in S2 is 350-400°C, preferably 380°C, and the pyrolysis time is 30min±5min.

[0053] Specifically, the concentration of the water-coal slurry obtained in S3 is 60-70%, preferably 60%.

[0054] Specifically, the gasification temperature of S4 is 1300-1400°C, and the preferred gasification temperature is 1350°C.

[0055] Specifically, the high-temperature and high-pressure steam obtained in S5 has a temperature of 500 to 550° C., preferably 550° C., and a pressure of 9 to 9.8 MPa, preferably 9 MPa.

[0056] Specifically, the particle size of the semi-coke powder is 150-200 mesh;

[0057] Its function is: the setting of the particle size of the semi-coke powder increases the heating area of ​​the semi-coke and improves the gasification rate.

[0058] Among them, semi-coke powder is CO 2 As carrier gas, CO 2 The mass ratio of coke to semi-coke powder is 3 to 6:20.

[0059] In this embodiment, for the production of 21.75 cum of synthesis gas, under certain gasification conditions, the simulation results using Aspenplus chemical process simulation software show that the gasification process using only raw coal consumes 12.84 kg of raw coal, 12.37 kg of oxygen consumption, and the CO and H2 contents in the produced synthesis gas are 13.136 cum and 8.614 cum respectively; the process of this embodiment requires the consumption of 10 kg of raw coal, 11.177 kg of traditional Chinese medicine slag, and 12.1 kg of oxygen consumption. The CO and H2 contents in the synthesis gas are 13.437 cum and 8.312 cum respectively.

[0060] In summary, the process of this embodiment can save 22% of raw coal and 2% of oxygen compared with the gasification process (wet gasification) using only raw coal; compared with the gasification process using only raw coal, the content of CO in the synthesis gas generated by the process of this embodiment is increased, and the proportion of other components does not change significantly, which can meet the demand for synthesis gas; at the same time, compared with the gasification process using only raw coal, the process of this embodiment improves the utilization efficiency of water in the water-coal slurry due to the addition of semi-coke powder, so the content of water vapor in the crude synthesis gas is reduced, the total amount of synthesis gas produced is increased, the cold gas efficiency is also increased from 72% to 74%, and the specific oxygen consumption is increased from ~568Nm 3 / kNm 3 Reduced to ~556Nm 3 / kNm 3 .

[0061] Example 2

[0062] A water-coal slurry and solid waste pyrolysis co-gasification system of this embodiment, according to the process of embodiment 1, includes a solid waste drying pyrolysis mechanism, a water-coal slurry preparation mechanism, a crude synthesis gas preparation mechanism and a synthesis gas preparation circulation mechanism;

[0063] The solid waste drying and pyrolysis mechanism is used for dehydration, drying and pyrolysis of solid waste. The solid waste is dehydrated and dried to obtain dry water vapor and dry solid waste. The dry solid waste is pyrolyzed to obtain low-temperature water vapor, semi-coke, pyrolysis gas and tar. The semi-coke is crushed to obtain semi-coke powder, and the warm water vapor is circulated for dehydration and drying of the solid waste; the water-coal slurry preparation mechanism is used to cool the dry water vapor obtained by dehydration and drying of the solid waste into cooling water, and grind the raw coal and mix it with cooling water to obtain water-coal slurry; the crude synthesis gas preparation mechanism is used to mix semi-coke powder, pyrolysis gas, tar and water-coal slurry and then add oxygen for gasification to obtain crude synthesis gas; the synthesis gas preparation circulation mechanism is used to cool the crude synthesis gas output by the synthesis gas preparation mechanism to obtain synthesis gas and high-temperature and high-pressure water vapor, and the high-temperature and high-pressure water vapor provides heat to the pyrolysis cycle of the drying and pyrolysis mechanism.

[0064] Specifically, the drying pyrolysis mechanism includes a drying pyrolysis furnace 1 and a crusher 4, and the semi-coke discharge port of the drying pyrolysis furnace 1 is connected to the input end of the crusher 4;

[0065] Its functions are as follows: the drying pyrolysis furnace 1 is used to dehydrate the solid waste at a drying temperature of 120°C to obtain dry solid waste with a water vapor produced at 250-300°C and a water content of 5-10%, and then the dry solid waste is pyrolyzed at 380°C for 30 minutes to obtain low-temperature water vapor, semi-coke, pyrolysis gas and tar at 250-300°C; the crusher 4 is used to crush the semi-coke obtained by pyrolysis to obtain semi-coke powder with a particle size of 150-200 meshes;

[0066] Among them, low-temperature water vapor circulation is used to dehydrate and dry solid waste, saving energy;

[0067] The water-coal slurry preparation mechanism includes a first cooler 2 and a coal mill 3, wherein the input end of the first cooler 2 is connected to the dry water vapor outlet of the dry pyrolysis furnace 1, and the output end of the first cooler 2 is connected to the input end of the coal mill 3;

[0068] Its functions are as follows: the first cooler 2 is used to cool the dry water vapor obtained by dehydrating and drying the solid waste into cooling water, and the raw coal is ground in the coal mill 3 and mixed with the cooling water to obtain a water-coal slurry with a concentration of 60-70%;

[0069] The raw synthesis gas preparation mechanism includes a gasifier 5, the input end of the gasifier 5 is respectively connected to the pyrolysis gas outlet of the drying pyrolysis furnace 1, the output end of the crusher 4 and the output end of the coal mill 3;

[0070] Its function is as follows: the gasifier 5 is used to mix the semi-coke powder, pyrolysis gas, tar and water-coal slurry, then add oxygen and gasify them at 1350°C to obtain a crude synthesis gas;

[0071] The synthesis gas preparation circulation mechanism includes a second cooler 6, the input end of the second cooler 6 is connected to the output end of the gasifier 5, and the water vapor output end of the second cooler 6 is connected to the drying pyrolysis furnace 1;

[0072] Its functions are as follows: the second cooler 6 is used to cool the raw synthesis gas output by the gasifier 5 to obtain synthesis gas and high-temperature and high-pressure water vapor at 500-550°C; wherein the water vapor output end of the second cooler 6 is connected to the dry pyrolysis furnace 1 to realize the high-temperature and high-pressure water vapor to provide heat to the pyrolysis cycle of the dry pyrolysis mechanism; wherein the synthesis gas obtained meets the demand for synthesis gas.

[0073] Preferably, in order to improve energy utilization efficiency, the drying pyrolysis mechanism includes two drying pyrolysis furnaces 1, one of which performs pyrolysis reaction and the other performs drying. The energy required for pyrolysis and drying comes from low-temperature water vapor generated by heat recovery in the process.

[0074] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0075] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0076] In addition, the various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the content invented by the present disclosure.

Claims

1. A process for pyrolysis and co-gasification of water-coal slurry and solid waste, characterized in that: The steps include: S1, dehydrating and drying the solid waste to obtain dry water vapor and dry solid waste; The mass ratio of the dried solid waste: raw coal: oxygen is (0.6-1.3):1:(1-1.4); the moisture content of the solid waste is 50-80%, and the moisture content of the solid waste after drying is 5-10%; The dehydration and drying temperature of the solid waste in S1 is 105-120°C, and the temperature of the drying and water vapor produced by S1 is 115-120°C; S2, pyrolyzing the dry solid waste obtained in S1 to obtain low-temperature water vapor, semi-coke, pyrolysis gas and tar, and then crushing the semi-coke to obtain semi-coke powder; Among them, low-temperature water vapor circulates to S1 and is used for dehydration and drying of solid waste; The pyrolysis temperature of the dry solid waste in S2 is 350-400°C, the pyrolysis time is 30min±5min, and the particle size of the semi-coke powder is 150-200 mesh; S3, cooling the dry water vapor obtained in S1 to obtain cooling water, and grinding the raw coal and mixing it with the cooling water to obtain a water-coal slurry; The concentration of the water-coal slurry obtained in S3 is 60-70%; S4, mixing the semi-coke powder, pyrolysis gas and tar obtained in S2 and the water-coal slurry obtained in S3, and then adding oxygen for gasification to obtain a crude synthesis gas; The gasification temperature of S4 is 1300-1400°C; S5, cooling the crude synthesis gas obtained in S4 to obtain synthesis gas and high-temperature and high-pressure steam; The high temperature and high pressure steam provides heat for the pyrolysis of S2; The high-temperature and high-pressure steam obtained in S5 has a temperature of 500 to 550° C. and a pressure of 9 to 9.8 MPa.

2. A water-coal slurry and solid waste pyrolysis co-gasification system, characterized in that: The process according to claim 1 comprises a solid waste drying and pyrolysis mechanism, a water-coal slurry preparation mechanism, a crude synthesis gas preparation mechanism and a synthesis gas preparation circulation mechanism; The solid waste drying and pyrolysis mechanism is used for dehydration, drying and pyrolysis of solid waste. The solid waste is dehydrated and dried to obtain dry water vapor and dry solid waste. The dry solid waste is pyrolyzed to obtain low-temperature water vapor, semi-coke, pyrolysis gas and tar. The semi-coke is crushed to obtain semi-coke powder. The warm water vapor is circulated for dehydration and drying of the solid waste. The water-coal slurry preparation mechanism is used to cool the dry water vapor obtained by dehydrating and drying the solid waste into cooling water, and grind the raw coal and mix it with the cooling water to obtain the water-coal slurry; The crude synthesis gas preparation mechanism is used to mix the semi-coke powder, pyrolysis gas, tar and water-coal slurry and then add oxygen for gasification to obtain crude synthesis gas; The synthesis gas preparation circulation mechanism is used to cool the raw synthesis gas output by the synthesis gas preparation mechanism to obtain synthesis gas and high-temperature and high-pressure steam, and the high-temperature and high-pressure steam provides heat to the pyrolysis cycle of the drying pyrolysis mechanism.

3. The water-coal slurry and solid waste pyrolysis co-gasification system according to claim 2, characterized in that: The drying pyrolysis mechanism comprises a drying pyrolysis furnace (1) and a crusher (4), wherein the semi-coke discharge port of the drying pyrolysis furnace (1) is connected to the input end of the crusher (4); The water-coal slurry preparation mechanism comprises a first cooler (2) and a coal mill (3), wherein the input end of the first cooler (2) is connected to the dry water vapor outlet of the dry pyrolysis furnace (1), and the output end of the first cooler (2) is connected to the input end of the coal mill (3); The raw synthesis gas preparation mechanism comprises a gasifier (5), the input end of the gasifier (5) is respectively connected to the pyrolysis gas outlet of the drying pyrolysis furnace (1), the output end of the crusher (4) and the output end of the coal mill (3); The synthesis gas preparation circulation mechanism comprises a second cooler (6), the input end of the second cooler (6) is connected to the output end of the gasifier (5), and the water vapor output end of the second cooler (6) is connected to the drying pyrolysis furnace (1).

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