A device and method for coordinated treatment of saline wastewater by split-flow coal gasification heat recovery.

Abstract

This invention discloses a device and method for coordinated treatment of saline wastewater through a split-flow coal gasification heat recovery system. The device includes a coal gasifier, a syngas cooler, a cyclone separator, a material feeder, a particulate matter controller, raw material burners, a saline wastewater feeder, and lined pipes. This invention injects oxygen into the generated crude syngas through an oxygen nozzle at the connection between the coal gasifier and the lined pipes, causing the carbonaceous materials in the crude syngas to undergo a combustion reaction with the oxygen, thus reheating the crude syngas and preventing the molten fly ash from solidifying; instead, it exists in the form of a molten fluid. Solid particles are used as the heat transfer medium; the specific surface area of ​​the solid particles is extremely large, resulting in an overall heat transfer coefficient more than five times that of traditional radiant waste boilers. This invention achieves the coordinated treatment of saline wastewater and the generation of vitreous material while recovering the sensible heat of the crude syngas. The cooling and purification process of the crude syngas in this invention is entirely a dry process, with no water-containing fine slag generated.

Description

Technical Field

[0001] This invention belongs to the technical field of syngas production and saline wastewater treatment, specifically relating to a device and method for coordinated treatment of saline wastewater by a split-flow coal gasification heat recovery system. Background Technology

[0002] Coal is the world's most abundant and widely distributed fossil fuel, providing a favorable environment for the development of the coal chemical industry. The clean and efficient utilization of coal is a major technological challenge in the fields of energy and environmental protection today.

[0003] In recent years, many foreign companies have conducted research and development on combined cycle gasification power generation technology to improve the thermal efficiency of coal-fired power plants, thus promoting the development of coal gasification technology. In existing industrial plants, there are two common processes for recovering heat from high-temperature syngas: one is the waste heat boiler process, represented by Shell's dry pulverized coal gasifier, and the other is the quench process, represented by GE's (formerly Texaco) coal-water slurry gasifier. Shell's gasification process has disadvantages such as low efficiency in cooling syngas, increased equipment investment, high compressor power consumption, and the need for circulating dust removal of the syngas used for quenching. GE's coal-water slurry gasification process has two forms of syngas heat recovery: a gasifier using direct quenching or a gasifier equipped with a radiant cooler. In the direct quench gasifier, high-temperature syngas is sprayed with water in the quench chamber and quenched to 130–260°C, directly converting the sensible heat of the syngas into steam during the washing process. This method of converting high-temperature heat sources into low-grade, low-temperature heat energy is extremely unreasonable in terms of heat energy utilization, and the value of heat recovery is also low. Gasifiers equipped with radiant coolers employ either water-cooled wall structures or water-tube structures. High-temperature syngas first undergoes radiant heat exchange through the descending channel of the radiant cooler, reducing its temperature to the range of 250–600°C, before being quenched with water to remove slag. In this heat recovery method, molten ash easily adheres to the surface of the water-cooled walls or water tubes, which can severely reduce the heat transfer efficiency of the radiant cooler.

[0004] In addition, a direct contact gas quenching mode can be used to directly mix the high-temperature crude syngas with the cold gas, thereby reducing the temperature of the mixed gas and promoting the cooling and solidification of molten fly ash. The disadvantage of this method is that direct gas quenching consumes a lot of energy. High-temperature convection waste heat boilers can also be used to recover the sensible heat of crude syngas. The disadvantages of this method are that the investment in heat exchangers is large, and the solidified fine slag particles are prone to accumulation and affect the normal operation of the equipment. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems existing in the prior art and to provide an apparatus and method for coordinated treatment of saline wastewater by a split-flow coal gasification heat recovery system.

[0006] To achieve the above objectives, the present invention provides a device for coordinated treatment of saline wastewater through a split-flow coal gasification heat recovery system, comprising a coal gasifier, a syngas cooler, a cyclone separator, a particulate matter controller, and lined pipes. The coal gasifier is divided from bottom to top into a slag-water zone, a reaction zone, and a constant-temperature zone. The syngas cooler is divided from bottom to top into a dense phase zone, a transition zone, a heat exchange zone, and a separation zone. The particulate matter controller is divided from bottom to top into a cooling zone, a moving zone, and a desolvation zone. The reaction zone of the coal gasifier is equipped with a feed burner, and the constant-temperature zone is equipped with an oxygen nozzle. The top of the gasifier is connected to the dense phase zone of the syngas cooler via lined pipes. The dense phase zone of the syngas cooler is connected to the saline wastewater feed device, and the separation zone is connected to the cyclone separator. The upper part of the separator is connected; the bottom of the cyclone separator is connected to the transition zone of the syngas cooler through the material leg and the circulating sealed tank; the heat exchange zone of the syngas cooler is equipped with a heat exchange system, which is connected to the boiler feedwater system; the bottom outlet of the syngas cooler is connected to the glass collector through a No. 1 continuous cooling pressure reduction and ash discharge device; the top of the cyclone separator is connected to the desolidification zone of the particulate matter controller; the desolidification zone of the particulate matter controller is equipped with a gas-solid separation unit, the moving zone is equipped with a fine powder level monitoring system, and the cooling zone is connected to the downstream ash silo through a No. 2 continuous cooling pressure reduction and ash discharge device; the top of the particulate matter controller is connected to the crude syngas subsequent treatment system and the backflushing system respectively.

[0007] Furthermore, there are at least two raw material burners, and the angle between the centerlines of adjacent raw material burners is 360° divided by the total number of raw material burners.

[0008] Furthermore, a saline wastewater nozzle is provided at the connection between the dense phase zone of the aforementioned syngas cooler and the saline wastewater feed device.

[0009] Furthermore, the angle α between the aforementioned lining pipe and the horizontal plane is 10° to 45°.

[0010] The method for coordinated treatment of saline wastewater by using the above-mentioned device to achieve heat recovery from upstream and downstream coal gasification includes the following steps:

[0011] a) Before starting work, a cooling water bath should be set up in the slag and water area of ​​the coal gasification furnace, and solid particles heated to 200-400°C should be filled into the material leg.

[0012] b) Use the feed burners in the reaction zone of the coal gasifier to inject preheated fuel and air and ignite them to raise the temperature of the reaction zone of the coal gasifier to 950°C, while ensuring that the temperature of the dense phase zone of the syngas cooler is above 300°C.

[0013] c) Replace the preheated fuel injected into the feedstock burner with gasification feedstock and gasifying agent, and adjust the ratio of gasification feedstock and gasifying agent to gradually increase and stabilize the temperature of the coal gasifier reaction zone to 1200-1600℃, so that the gasification feedstock and gasifying agent undergo gasification reaction in the reaction zone to generate crude syngas. The generated crude syngas carries molten fly ash and flows upward into the constant temperature zone; at the same time, start the syngas cooler, heat exchange system and boiler feedwater system.

[0014] d) Start the oxygen nozzle in the constant temperature zone of the coal gasifier and inject oxygen into the crude syngas. The amount of oxygen injected is 1 to 5 vol% of the total crude syngas entering the lining pipe.

[0015] e) Gradually add solid particles from the feed leg into the syngas cooler until the solid particle content in the transition zone of the syngas cooler reaches 0.3 to 0.6 times the total volume of the syngas cooler; as the operating temperature of the separation zone of the syngas cooler reaches 200 to 500°C, the syngas cooler begins normal circulating fluidization; the water from the boiler feedwater system exchanges heat with the crude syngas in the heat exchange zone of the syngas cooler through the heat exchange system to generate steam, and the crude syngas after heat exchange enters the cyclone separator from the separation zone, and the generated steam is incorporated into the steam pipeline network;

[0016] f) Start the backflush system at the top of the particulate matter controller to perform regular backflush operations on the desolidification zone; at the same time, start the cooling water supply to the cooling zone and the fine powder level monitoring system in the moving zone; the coarse syngas, after further separation by the cyclone separator, enters the desolidification zone of the particulate matter controller, and after further separation in the gas-solid separation unit, it enters the coarse syngas post-processing system, and the resulting fine powder enters the moving zone of the particulate matter controller downwards.

[0017] g) Start the No. 2 continuous cooling pressure reduction and ash discharge device to cool and depressurize the fine powder in the moving area of ​​the particulate matter controller and discharge it to the downstream ash silo.

[0018] h) Start the saline wastewater feeding device and spray saline wastewater into the dense phase zone of the syngas cooler. At the same time, start the No. 1 continuous cooling pressure reduction and ash discharge device. The molten fly ash entrained in the crude syngas and the soluble salt solids in the saline wastewater are converted into glass in the dense phase zone and transition zone of the syngas cooler. The No. 1 continuous cooling pressure reduction and ash discharge device cools and depressurizes the glass before discharging it to the glass collector.

[0019] After completing the above steps, the entire device will enter the normal production process.

[0020] Furthermore, in step c) above, when the gasification feedstock is dry coal powder, the gasifying agent is oxygen and steam, and the crude syngas composition is: CH4 content of 0.01–0.1 vol%, H2 content of 5–15 vol%, CO content of 35–45 vol%, CO2 content of 3–10 vol%, and water content of 35–45 vol%. When the gasification feedstock is coal-water slurry, the gasifying agent is oxygen, and the crude syngas composition is: CH4 content of 0.01–0.1 vol%, H2 content of 15–25 vol%, CO content of 20–30 vol%, CO2 content of 10–15 vol%, and water content of 40–50 vol%.

[0021] Furthermore, in step d) above, the apparent velocity of the crude syngas in the lining pipe is 10–25 m / s.

[0022] Furthermore, in step e) above, the operating pressure of the syngas cooler after normal circulating fluidization is 1-8 MPaG, the operating temperature of the dense phase zone is 1250-1600℃, the operating temperature of the transition zone is 800-900℃, the operating temperature of the heat exchange zone is 200-800℃, and the operating temperature of the separation zone is 200-500℃.

[0023] Furthermore, the particle size of the solid particles is 50–200 μm, and in step e), the apparent velocity of the crude syngas participating in the circulating fluidization of the solid particles is 0.5–10 m / s.

[0024] Furthermore, in step e) above, the steam pressure generated by the boiler feedwater system via the heat exchange system is 0.5–10 MPaG, and the temperature is 150–540°C.

[0025] Furthermore, in step h) above, the salt content of the saline wastewater is mainly NaCl and Na2SO4, and its total dissolved solids content is 10,000 to 60,000 mg / L.

[0026] The beneficial effects of this invention are as follows:

[0027] 1. In this invention, oxygen is injected into the generated crude syngas through an oxygen nozzle at the connection between the constant temperature zone of the coal gasifier and the lining pipe. This causes the carbon-containing materials in the crude syngas to undergo an oxidation reaction with the oxygen, releasing heat and reheating the crude syngas. The heated crude syngas, carrying molten fly ash, flows upward into the lining pipe, preventing the molten fly ash from solidifying. Instead, it exists in a molten state and exhibits fluid flow properties with a viscosity of 20 Pa·s.

[0028] 2. This invention uses solid particles as a heat transfer medium, so that the high-temperature crude syngas and solid particles are completely mixed in the dense phase zone and transition zone of the syngas cooler. The heat of the crude syngas is first transferred to the solid particles, and then the solid particles directly contact the heat exchange system in the heat exchange zone. The solid particles have a very large specific surface area, so the overall heat transfer coefficient is more than 5 times that of the traditional radiant waste boiler, and the equipment investment is small.

[0029] 3. This invention utilizes a syngas cooler to cool and recover heat from the high-temperature crude syngas from the coal gasification furnace. It solidifies the molten fly ash entrained in the high-temperature crude syngas and the soluble salts from the saline wastewater feeder into a glassy substance. During the temperature drop from above 1250℃ to below 900℃, this glassy substance undergoes granulation in the dense phase and transition zones, using solid particles from the syngas cooler as auxiliary materials. This achieves the simultaneous treatment of saline wastewater and the generation of sodalite-like material (Na4Al3Si3O4) while recovering the sensible heat of the crude syngas. 12 The glassy form of products such as Cl), calcium chlorosilicate (Ca7(SiO4)2Cl6), and lapis lazuli (Na6Ca2(AlSiO4)6(SO4)4) was obtained, which enabled the co-treatment of saline wastewater and the generation of glassy form during the recovery of the sensible heat of crude syngas.

[0030] 4. The cooling and purification process of the crude syngas in this invention adopts a completely dry process, thereby avoiding the method of water washing and solidification of the crude syngas. Instead, the particulate matter in the crude syngas is removed by gas-solid separation, and no water-containing fine residue is generated in this process. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of the device of the present invention.

[0032] In the diagram: 1-Coal gasification furnace, 2-Synthesis gas cooler, 3-Cyclone separator, 4-Feed leg, 5-Circulating sealed tank, 6-Particulate matter controller, 7-No. 1 continuous pressure reducing cooling and ash removal device, 8-No. 2 continuous pressure reducing cooling zone ash removal device, 9-Raw material burner, 10-Heat exchange system, 11-Material level detection system, 12-Gas-solid separation unit, 13-Backflush system, 14-Glass collector, 15-Saline wastewater feeder, 16-Lined pipe, 17-Downstream ash silo, 18-Boiler feedwater system, 19-Crude syngas post-treatment system. Detailed Implementation

[0033] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments, but the scope of protection of the present invention is not limited to these embodiments.

[0034] like Figure 1As shown, the device for coordinated treatment of saline wastewater by upper and lower flow type coal gasification heat recovery according to the present invention includes a coal gasifier 1, a syngas cooler 2, a cyclone separator 3, a material leg 4, a circulating sealed tank 5, a particulate matter controller 6, a first continuous pressure reduction cooling ash discharge device 7, a second continuous pressure reduction cooling ash discharge device 8, a raw material burner 9, a heat exchange system 10, a material level detection system 11, a gas-solid separation unit 12, a backflushing system 13, a glass collector 14, a saline wastewater feeding device 15, a lined pipe 16, a downstream ash silo 17, a boiler feedwater system 18, and a crude syngas post-treatment system 19.

[0035] The coal gasifier 1 is divided into a slag-water zone, a reaction zone, and a constant temperature zone from bottom to top. The syngas cooler 2 is divided into a dense phase zone, a transition zone, a heat exchange zone, and a separation zone from bottom to top. The particulate matter controller 6 is divided into a cooling zone, a moving zone, and a desolidification zone from bottom to top.

[0036] The slag-water zone of the coal gasifier 1 is equipped with a coarse slag cooling water bath, and the reaction zone is equipped with raw material burners 9 and oxygen nozzles. The top of the reaction zone is connected to the dense phase zone of the syngas cooler 2 through a lining pipe 16. The inner walls of the reaction zone and the constant temperature zone of the coal gasifier 1 are both lined with refractory linings; there are at least two raw material burners 9, and the included angle between the centerlines of adjacent raw material burners 9 is 360° divided by the total number of raw material burners 9; the included angle α between the lining pipe 16 and the horizontal plane is 10° to 45°. After the gasification feedstock and gasifying agent undergo a gasification reaction in the reaction zone of the coal gasifier 1, the generated crude syngas, carrying molten fly ash, flows upward into the constant temperature zone. The carbonaceous materials in the crude syngas react with oxygen injected through the oxygen nozzle, releasing heat and further heating the crude syngas before it enters the lining pipe 16. This prevents the temperature of the crude syngas from dropping, which could cause the molten fly ash to stick to the wall and form slag. Simultaneously, the heated crude syngas, carrying molten fly ash, enters the lining pipe 16, preventing the molten fly ash from solidifying and allowing it to exist as a molten fluid. The coarse slag falls downwards into the water bath of the slag-water zone due to gravity, where it is cooled and discharged to the downstream slag pool.

[0037] The dense phase zone of the syngas cooler 2 is connected to the saline wastewater feed device 15, and the separation zone is connected to the upper part of the cyclone separator 3. The bottom of the cyclone separator 3 is connected to the transition zone of the syngas cooler 2 via the material leg 4 and the circulating sealed tank 5. A saline wastewater nozzle is provided at the connection between the dense phase zone of the syngas cooler 2 and the saline wastewater feed device 15. A heat exchange system 10 is provided in the heat exchange zone, and the heat exchange system 10 is connected to the boiler feedwater system 18. The heat exchange system 10 consists of a saturation unit, a superheating unit, and a preheating unit. The bottom outlet of the syngas cooler 2 is connected to the glass collector 14 via a first continuous cooling pressure reducing ash removal device 7. The material leg 4 is used to fill solid particles with a particle size of 50-200 μm, specifically corundum, quartz sand, catalyst, etc. Syngas cooler 2 uses circulating fluidized solid particles as the heat transfer medium, so that the high-temperature crude syngas and solid particles are completely mixed in the dense phase zone and transition zone of syngas cooler 2. The heat of crude syngas is first transferred to solid particles, and then the solid particles directly contact the heat exchange system 10 in the heat exchange zone. The solid particles have a very large specific surface area, so the overall heat transfer coefficient is more than 5 times that of traditional radiant waste boilers. At the same time, syngas cooler 2 cools down the high-temperature crude syngas from coal gasifier 1 and recovers heat. It solidifies the molten fly ash entrained in the high-temperature crude syngas and the soluble salts from the saline wastewater feeder 15 into a glassy substance. The glassy substance is granulated in the dense phase zone and transition zone with the solid particles in syngas cooler 2 as auxiliary material. Finally, the granulated glassy substance is cooled and discharged to the glassy substance collector 14 by the No. 1 continuous cooling pressure reduction ash discharge device 7.

[0038] The top of the cyclone separator 3 is connected to the desolidification zone of the particulate matter controller 6. The desolidification zone of the particulate matter controller 6 is equipped with a gas-solid separation unit 12, the moving zone is equipped with a fine powder level monitoring system 11, and the cooling zone is equipped with cooling water pipes. The cooling zone is connected to the downstream ash silo 17 through the second continuous cooling pressure reduction and ash discharge device 8. The top of the particulate matter controller 6 is connected to the crude syngas post-treatment system 19 and the backflushing system 13. The crude syngas separated by the cyclone separator 3 enters the desolidification zone of the particulate matter controller 6. After further separation in the gas-solid separation unit 12, the crude syngas enters the crude syngas post-treatment system 19. The resulting fine powder flows downward into the moving zone of the particulate matter controller 6. After the fine powder level monitoring system 11 detects that it has reached a certain level, it enters the cooling zone of the particulate matter controller 6. After being cooled by the second continuous cooling pressure reduction and ash discharge device 8, it is collected through the downstream ash silo 17.

[0039] The method for coordinated treatment of saline wastewater by using the above-mentioned device to achieve heat recovery from upstream and downstream coal gasification includes the following steps:

[0040] a) Before starting work, a cooling water bath is set up in the slag and water area of ​​the coal gasifier 1, and solid particles heated to 200-400°C are filled into the material leg 4.

[0041] b) The preheated fuel and air are injected into the raw material burner 9 in the reaction zone of the coal gasifier 1 and ignited to raise the temperature of the reaction zone of the coal gasifier 1 to 950°C, while ensuring that the temperature of the dense phase zone of the syngas cooler 2 is higher than 300°C.

[0042] c) Replace the preheated fuel injected into the feedstock burner 9 with gasification feedstock and gasifying agent, adjust the ratio of gasification feedstock and gasifying agent to gradually increase and stabilize the temperature of the reaction zone of the coal gasifier 1 to 1200-1600℃, so that the gasification feedstock and gasifying agent undergo gasification reaction in the reaction zone to generate crude syngas, and the generated crude syngas carries molten fly ash upward into the constant temperature zone; at the same time, start the syngas cooler 2, heat exchange system 10, boiler feedwater system 18.

[0043] d) Start the oxygen nozzle at the connection between the constant temperature zone of the coal gasifier 1 and the lining pipe 16, and inject oxygen into the crude syngas entering the lining pipe 16. The amount of oxygen injected is 1 to 5 vol% of the total amount of crude syngas entering the lining pipe 16.

[0044] e) Gradually add solid particles from feed leg 4 into syngas cooler 2, until the solid particle content in the transition zone of syngas cooler 2 reaches 0.3 to 0.6 times the total volume of syngas cooler 2; as the operating temperature of the separation zone of syngas cooler 2 reaches 200 to 500°C, syngas cooler 2 begins normal circulating fluidization; water from boiler feedwater system 18 exchanges heat with the crude syngas in the heat exchange zone of syngas cooler 2 through heat exchange system 10 to generate steam, and the crude syngas after heat exchange enters cyclone separator 3 from the separation zone, and the generated steam is incorporated into the steam pipeline network;

[0045] f) Start the back-flushing system 13 at the top of the particulate matter controller 6 to perform periodic back-flushing operations on the desolidification zone; at the same time, start the cooling water supply system in the cooling zone and the fine powder level monitoring system 11 in the moving zone; the coarse syngas after further separation by the cyclone separator 3 enters the desolidification zone of the particulate matter controller 6, and after further separation in the gas-solid separation unit 12, it enters the coarse syngas post-processing system 19, and the generated fine powder enters the moving zone of the particulate matter controller 6 downwards;

[0046] g) Start the No. 2 continuous cooling pressure reduction and ash discharge device 8 to cool and depressurize the fine powder in the moving area of ​​the particulate matter controller 6 and discharge it to the downstream ash silo 17.

[0047] h) Start the saline wastewater feeding device 15 and spray saline wastewater into the dense phase zone of the syngas cooler 2. At the same time, start the No. 1 continuous cooling pressure reduction and ash discharge device 7. The molten fly ash entrained in the crude syngas and the soluble salt solids in the saline wastewater are converted into glass in the dense phase zone and transition zone of the syngas cooler 2. The No. 1 continuous cooling pressure reduction and ash discharge device 7 cools the glass and depressurizes it before discharging it to the glass collector 14.

[0048] After completing the above steps, the entire device will enter the normal production process.

[0049] In step c) above, when the gasification feedstock is dry coal powder, the gasifying agent is oxygen and steam, and the crude syngas composition is: CH4 content of 0.01-0.1 vol%, H2 content of 5-15 vol%, CO content of 35-45 vol%, CO2 content of 3-10 vol%, and water content of 35-45 vol%. When the gasification feedstock is coal-water slurry, the gasifying agent is oxygen, and the crude syngas composition is: CH4 content of 0.01-0.1 vol%, H2 content of 15-25 vol%, CO content of 20-30 vol%, CO2 content of 10-15 vol%, and water content of 40-50 vol%.

[0050] In step d) above, the apparent velocity of the crude syngas in the lining pipe 16 is 10-25 m / s.

[0051] In step e) above, the operating pressure of the syngas cooler 2 after normal circulating fluidization is 1-8 MPaG, the operating temperature of the dense phase zone is 1250-1600℃, the operating temperature of the transition zone is 800-900℃, the operating temperature of the heat exchange zone is 200-800℃, and the operating temperature of the separation zone is 200-500℃; the steam pressure generated by the boiler feedwater system 18 through the heat exchange system 10 is 0.5-10 MPaG, and the temperature is 150-540℃; the apparent velocity of the crude syngas participating in the circulating fluidization of solid particles is 0.5-10 m / s.

[0052] In step h) above, the salt content of the saline wastewater is mainly NaCl and Na2SO4, and its total dissolved solids content is 10,000 to 60,000 mg / L.

[0053] Example 1

[0054] Bituminous coal is ground into dry pulverized coal using a dry mill as the gasification feedstock, with oxygen and steam used as gasifying agents. Preheated fuel and air are injected and ignited through four feedstock burners (9) in the reaction zone of gasifier 1. Once the temperature in the reaction zone of gasifier 1 reaches 950℃, the preheating fuel is replaced with dry pulverized coal, and the air is replaced with oxygen and steam. The dry pulverized coal flow rate of each feedstock burner (9) is gradually increased to 31.25 t / h, while the oxygen and steam flow rates are gradually increased to 67500 Nm³. 3 With a flow rate of 10000 kg / h and 10000 kg / h, the temperature in the reaction zone of gasifier 1 gradually increases and stabilizes at approximately 1600℃. The pressure in gasifier 1 is 4 MPaG. The operating temperature in the dense phase zone is 1350℃, the operating temperature in the transition zone is 850℃, the operating temperature in the heat exchange zone is 500℃, and the operating temperature in the separation zone is 240℃. During this process, 500 Nm³ of oxygen is injected into the crude syngas entering the lining pipe 16. 3 The temperature of the crude syngas is maintained above 1600℃, and the apparent velocity of the crude syngas in the lined pipe 16 is 18 m / s. Subsequently, 130 t / h of saline wastewater (the main salts in the saline wastewater are NaCl and Na2SO4, with a total dissolved solids content of 10000 mg / L) is injected into the dense phase zone of the syngas cooler 2. The molten fly ash entrained in the high-temperature crude syngas and the soluble salts from the saline wastewater are solidified and transformed into sodalite-like material (Na4Al3Si3O4). 12 The syngas consists of a glassy mass primarily composed of Cl, calcium chlorosilicate (Ca7(SiO4)2Cl6), and kosmochlor (Na6Ca2(AlSiO4)6(SO4)4). This glassy mass is granulated in the dense phase and transition zones using quartz sand (50–200 μm particle size) circulating fluidized within the syngas cooler 2 as an auxiliary material. The apparent velocity of the crude syngas participating in the quartz sand circulation fluidization is 5 m / s. Approximately 3.5 t / h of glassy mass is generated at this point and discharged from the first continuous cooling and pressure reducing ash removal device 7. After passing through the syngas cooler 2, the temperature of the crude syngas drops to 240℃. At this point, the heat exchange system 10 generates 150 t / h of steam at a pressure of 10 MPaG and a temperature of 540℃. After passing through the particulate matter controller 6, the solid content of the crude syngas is less than 0.1 ppm, with a 99.99% removal efficiency for 1 μm particles. The final crude syngas composition was: CH4 content 0.01 vol%, H2 content 13 vol%, CO content 38 vol%, CO2 content 4 vol%, and water content 44.5 vol%.

[0055] Example 2

[0056] Bituminous coal is ground into a 62% (w / w) coal-water slurry using a wet mill, which serves as the gasification feedstock, with oxygen as the gasifying agent. Preheated fuel and air are injected and ignited at two burners (9) in the reaction zone of gasifier 1. Once the temperature in the reaction zone of gasifier 1 reaches 950℃, the preheating fuel is replaced with coal-water slurry, and the air is replaced with oxygen. The flow rate of the coal-water slurry at each burner (9) is gradually increased to 62.5 t / h, while the oxygen flow rate is gradually increased to 85000 Nm³. 3 The gasification process is as follows: At a rate of / h, the temperature in the reaction zone of gasifier 1 gradually increases and stabilizes at approximately 1350℃. The pressure in gasifier 1 is 6.5 MPaG. The operating temperature in the dense phase zone is 1250℃, the transition zone is 850℃, the heat exchange zone is 500℃, and the separation zone is 280℃. During this process, 500 Nm³ of oxygen is injected into the crude syngas entering the lining pipe 16. 3 The temperature of the crude syngas is maintained above 1350℃, and the apparent velocity of the crude syngas in the lined pipe 16 is 18 m / s. Subsequently, 80 t / h of saline wastewater (the main salts in the saline wastewater are NaCl and Na2SO4, with a total dissolved solids content of 10000 mg / L) is injected into the dense phase zone of the syngas cooler 2. The molten fly ash entrained in the high-temperature crude syngas and the soluble salts from the saline wastewater are solidified and transformed into sodalite-like material (Na4Al3Si3O4). 12 The syngas consists of a glassy mass primarily composed of Cl, calcium chlorosilicate (Ca7(SiO4)2Cl6), and kosmochlor (Na6Ca2(AlSiO4)6(SO4)4). This glassy mass is granulated in the dense phase and transition zones using quartz sand (50–200 μm particle size) circulating fluidized within the syngas cooler 2 as an auxiliary material. The apparent velocity of the crude syngas participating in the quartz sand circulation fluidization is 5 m / s. Approximately 2 t / h of glassy mass is generated at this point and discharged from the first continuous cooling and pressure reducing ash removal device 7. After passing through the syngas cooler 2, the temperature of the crude syngas drops to 260℃. At this point, the heat exchange system 10 generates 60 t / h of steam with a pressure of 10 MPaG and a temperature of 540℃. After passing through the particulate matter controller 6, the solid content of the crude syngas is less than 0.1 ppm, with a 99.99% removal efficiency for 1 μm particles. The final crude syngas composition was: CH4 content 0.03 vol%, H2 content 17 vol%, CO content 26 vol%, CO2 content 10 vol%, and water content 46.5 vol%.

Claims

1. A device for coordinated treatment of saline wastewater through a split-flow coal gasification heat recovery system, characterized in that, Includes a coal gasifier (1), a syngas cooler (2), a cyclone separator (3), a particulate matter controller (6), and lined pipes (16); The coal gasifier (1) is divided into a slag-water zone, a reaction zone and a constant temperature zone from bottom to top. The syngas cooler (2) is divided into a dense phase zone, a transition zone, a heat exchange zone and a separation zone from bottom to top. The particulate matter controller (6) is divided into a cooling zone, a moving zone and a desolidification zone from bottom to top. The reaction zone of the coal gasification furnace (1) is equipped with a raw material burner (9), the constant temperature zone is equipped with an oxygen nozzle, and the top is connected to the dense phase zone of the syngas cooler (2) through a lining pipe (16). The dense phase zone of the syngas cooler (2) is connected to the saline wastewater feed device (15), and the separation zone is connected to the upper part of the cyclone separator (3). The bottom of the cyclone separator (3) is connected to the transition zone of the syngas cooler (2) through the material leg (4) and the circulating sealed tank (5). The heat exchange zone of the syngas cooler (2) is equipped with a heat exchange system (10), which is connected to the boiler feedwater system (18). The bottom outlet of the syngas cooler (2) is connected to the glass collector (14) through the No. 1 continuous cooling pressure reducing ash discharge device (7). The top of the cyclone separator (3) is connected to the desolidification zone of the particulate matter controller (6); the desolidification zone of the particulate matter controller (6) is equipped with a gas-solid separation unit (12), the moving zone is equipped with a fine powder level monitoring system (11), and the cooling zone is connected to the downstream ash silo (17) through the No. 2 continuous cooling pressure reduction ash discharge device (8); the top of the particulate matter controller (6) is connected to the crude syngas subsequent treatment system (19) and the backflushing system (13) respectively.

2. The apparatus for coordinated treatment of saline wastewater by upper and lower flow split-flow coal gasification heat recovery according to claim 1, characterized in that, There are at least two raw material burners (9), and the angle between the centerlines of adjacent raw material burners (9) is 360° divided by the total number of raw material burners (9).

3. The apparatus for coordinated treatment of saline wastewater by upper and lower flow split-flow coal gasification heat recovery according to claim 1, characterized in that, The angle α between the lining pipe (16) and the horizontal plane is 10° to 45°; a saline wastewater nozzle is provided at the connection between the dense phase zone of the syngas cooler (2) and the saline wastewater feed device (15).

4. A method for coordinated treatment of saline wastewater by using the apparatus described in claim 1 for upstream and downstream split-flow coal gasification heat recovery, characterized in that, Includes the following steps: a) Before starting work, a cooling water bath is set up in the slag water area of ​​the coal gasification furnace (1), and solid particles heated to 200-400°C are filled into the material leg (4); b) The preheated fuel and air are injected into the raw material burner (9) of the reaction zone of the coal gasifier (1) and ignited to raise the temperature, thereby raising the temperature of the reaction zone of the coal gasifier (1) to 950°C, while ensuring that the temperature of the dense phase zone of the syngas cooler (2) is higher than 300°C. c) Replace the preheated fuel injected into the raw material burner (9) with gasification raw material and gasification agent, adjust the ratio of gasification raw material and gasification agent to gradually increase the temperature of the reaction zone of the coal gasifier (1) and stabilize it at 1200-1600℃, so that the gasification raw material and gasification agent can undergo gasification reaction in the reaction zone to generate crude syngas. The generated crude syngas carries molten fly ash and flows upward into the constant temperature zone; at the same time, start the syngas cooler (2), heat exchange system (10), and boiler feedwater system (18). d) Start the oxygen nozzle in the constant temperature zone of the coal gasifier (1) and inject oxygen into the crude syngas. The amount of oxygen injected is 1 to 5 vol% of the total crude syngas entering the lining pipe (16). e) Gradually add solid particles from the feed leg (4) into the syngas cooler (2) until the solid particle content in the transition zone of the syngas cooler (2) reaches 0.3 to 0.6 times the total volume of the syngas cooler (2); as the operating temperature of the separation zone of the syngas cooler (2) reaches 200 to 500°C, the syngas cooler (2) begins normal circulating fluidization; the water from the boiler feedwater system (18) exchanges heat with the crude syngas in the heat exchange zone of the syngas cooler (2) through the heat exchange system (10) to generate steam, and the crude syngas after heat exchange enters the cyclone separator (3) from the separation zone, and the generated steam is incorporated into the steam pipeline network; f) Start the backflush system (13) at the top of the particulate controller (6) to perform periodic backflush operations on the desolidification zone; at the same time, start the cooling water supply system in the cooling zone and the fine powder level monitoring system (11) in the moving zone; the coarse syngas after further separation by the cyclone separator (3) enters the desolidification zone of the particulate controller (6), and after further separation in the gas-solid separation unit (12), it enters the coarse syngas post-processing system (19), and the generated fine powder enters the moving zone of the particulate controller (6) downwards; g) Start the No. 2 continuous cooling pressure reduction and ash discharge device (8) to cool and depressurize the fine powder in the moving area of ​​the particulate matter controller (6) and discharge it to the downstream ash silo (17); h) Start the saline wastewater feeding device (15) and spray saline wastewater into the dense phase zone of the syngas cooler (2). At the same time, start the No. 1 continuous cooling pressure reduction and ash discharge device (7). The molten fly ash entrained in the crude syngas and the soluble salt solids in the saline wastewater are transformed into glass in the dense phase zone and transition zone of the syngas cooler (2). The No. 1 continuous cooling pressure reduction and ash discharge device (7) cools the glass and depressurizes it before discharging it to the glass collector (14). After completing the above steps, the entire device will enter the normal production process.

5. The method for coordinated treatment of saline wastewater by split-flow coal gasification heat recovery according to claim 4, characterized in that, In step c), when the gasification feedstock is dry coal powder, the gasifying agent is oxygen and steam, and the crude syngas composition is: CH4 content 0.01-0.1 vol%, H2 content 5-15 vol%, CO content 35-45 vol%, CO2 content 3-10 vol%, and water content 35-45 vol%. When the gasification feedstock is coal-water slurry, the gasifying agent is oxygen, and the crude syngas composition is: CH4 content 0.01-0.1 vol%, H2 content 15-25 vol%, CO content 20-30 vol%, CO2 content 10-15 vol%, and water content 40-50 vol%.

6. The method for coordinated treatment of saline wastewater by split-flow coal gasification heat recovery according to claim 4, characterized in that, In step d), the apparent velocity of the crude syngas in the lining pipe (16) is 10-25 m / s.

7. The method for coordinated treatment of saline wastewater by split-flow coal gasification heat recovery according to claim 4, characterized in that, In step e), the operating pressure of the syngas cooler (2) after normal circulation fluidization is 1-8 MPaG, the operating temperature of the dense phase zone is 1250-1600℃, the operating temperature of the transition zone is 800-900℃, the operating temperature of the heat exchange zone is 200-800℃, and the operating temperature of the separation zone is 200-500℃.

8. The method for coordinated treatment of saline wastewater by split-flow coal gasification heat recovery according to claim 4, characterized in that, The particle size of the solid particles is 50-200 μm, and in step e), the apparent velocity of the crude syngas participating in the circulating fluidization of the solid particles is 0.5-10 m / s.

9. The method for coordinated treatment of saline wastewater by split-flow coal gasification heat recovery according to claim 4, characterized in that, In step e), the steam pressure generated by the boiler feedwater system (18) through the heat exchange system (10) is 0.5-10 MPaG and the temperature is 150-540℃.

10. The method for coordinated treatment of saline wastewater by split-flow coal gasification heat recovery according to claim 4, characterized in that, In step h), the salt content of the saline wastewater is mainly NaCl and Na2SO4, and its total dissolved solids content is 10,000 to 60,000 mg / L.

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