Device and method for co-treating wastewater by using coal water slurry

Abstract

The invention relates to the technical field of coal water slurry pressurized gasification and waste water treatment, in particular to a device and method for co-treating waste water through coal water slurry, the device comprises a gasification furnace system, a waste water and waste gas recovery treatment system and an oxidation furnace system, the gasification furnace system comprises a weighing coal feeder, a coal grinding mechanism, a coal slurry boosting mechanism and a gasification furnace which are communicated in sequence, the waste water and waste gas recovery treatment system comprises a waste water pipeline, a waste gas pipeline, an induced draft fan and an exhaust pipeline, the waste water pipeline is respectively communicated with the coal grinding mechanism and the oxidation furnace system, and the exhaust pipeline is respectively communicated with the coal grinding mechanism and the coal slurry boosting mechanism and is communicated with the waste gas pipeline through the induced draft fan; the waste gas pipeline is respectively communicated with the oxidizing furnace system and the boiler fan, and the oxidizing furnace system is also communicated with the flue gas after-treatment system. By adopting the device and the method for co-treating the wastewater by using the coal water slurry, the problems of safety, environmental protection and cost in a high-concentration organic wastewater treatment process are solved.

Description

Technical Field

[0001] The invention relates to the technical field of water-coal slurry pressurized gasification and wastewater treatment, and in particular to a device and method for co-disposing wastewater by using water-coal slurry. Background Art

[0002] In the process of continuous development of modern industry, the number of new and expanded projects of enterprises is increasing, which makes the amount of wastewater generated show an increasing trend year by year, and the pressure faced by wastewater treatment is also increasing dramatically. Taking the production equipment of pyridine, hydrogen peroxide, tetramethylbenzene, etc. as an example, the wastewater generated by them not only has a very high organic content, but also contains some toxic and harmful substances. The treatment of this type of wastewater is extremely difficult, and traditional sewage treatment equipment often fails to achieve the ideal effect when treating it. If outsourcing is chosen, the cost is even higher. If the wastewater generated cannot be treated in time, the temporary storage of wastewater in the factory area will increase, and the safety and environmental protection pressure will be great. Not only may it pose a potential threat to the surrounding environment, but it may also face risks in environmental protection supervision, affecting the normal production and operation of the enterprise.

[0003] At present, common treatment processes for this type of organic wastewater include biochemical, incineration and oxidation treatment. Although the biochemical treatment method is widely used in the field of wastewater treatment, its treatment process is lengthy, the control links during operation are complex, and it is more suitable for treating low-concentration wastewater. For high-concentration organic wastewater, the biochemical treatment effect is not good and the treatment cost will increase significantly. The incineration method and oxidation method are to oxidize hazardous wastes in an oxygen-rich state. This method is suitable for the treatment of hazardous wastes with high organic components and high calorific value. However, there are obvious defects in its treatment of wastewater. On the one hand, CO2 and NO will be produced during the treatment process. X , smoke, SO2, HCl, dioxins and other pollutants require corresponding secondary pollution control equipment, which undoubtedly increases the treatment cost and technical difficulty; on the other hand, when treating wastewater, the consumption of natural gas is large, resulting in high energy consumption and high operating costs. Summary of the invention

[0004] The purpose of the present invention is to provide a device and method for the coordinated treatment of wastewater by water-coal slurry, which solves the safety, environmental protection and cost problems in the treatment process of high-concentration organic wastewater.

[0005] To achieve the above-mentioned purpose, the present invention provides a device for the coordinated treatment of wastewater by water-coal slurry, comprising a gasification furnace system, a wastewater and waste gas recovery and treatment system and an oxidation furnace system, the gasification furnace system comprising a weighing coal feeder, a coal grinding mechanism, a coal slurry boosting mechanism and a gasification furnace connected in sequence, the wastewater and waste gas recovery and treatment system comprising a wastewater pipeline, a waste gas pipeline, an induced draft fan and an exhaust pipeline, the wastewater pipeline is respectively connected to the coal grinding mechanism and the oxidation furnace system, the exhaust pipeline is respectively connected to the coal grinding mechanism and the coal slurry boosting mechanism, the exhaust pipeline is connected to the waste gas pipeline through the induced draft fan, the waste gas pipeline is respectively connected to the oxidation furnace system and the boiler fan, and the oxidation furnace system is also connected to the flue gas post-treatment system.

[0006] Preferably, the coal grinding mechanism includes a coal grinding water tank, a grinding water pump and a coal grinding machine, the water inlet of the coal grinding water tank is connected to the fresh water pipeline and the waste water pipeline, and the water outlet of the coal grinding water tank is connected to the inlet chute of the coal grinding machine through the grinding water pump.

[0007] Preferably, the coal slurry boosting mechanism includes a drum screen, a mill discharge trough and a large coal slurry trough. The drum screen is arranged at the outlet of the coal mill. The bottom of the drum screen is connected to the mill discharge trough. The bottom of the mill discharge trough is connected to the large coal slurry trough through a low-pressure coal slurry pump. The bottom of the large coal slurry trough is connected to the gasifier through a high-pressure coal slurry pump.

[0008] Preferably, the top of the coal grinding water tank is provided with an exhaust port 1 connected to the exhaust pipeline, the top of the drum screen is provided with an exhaust port 2 connected to the exhaust pipeline, the top of the mill discharge trough is provided with an exhaust port 3 connected to the exhaust pipeline, and the top of the large coal slurry tank is provided with an exhaust port 4 connected to the exhaust pipeline.

[0009] Preferably, an overflow pipe is further provided at the bottom of the drum screen, and a check valve is provided on the overflow pipe.

[0010] Preferably, the oxidation furnace system includes an oxidation furnace and an oxidation furnace blower, the exhaust gas pipeline is connected to the oxidation furnace through the oxidation furnace blower, the waste water pipeline is connected to the waste water heat exchanger, and the waste water heat exchanger is connected to the oxidation furnace.

[0011] Preferably, the flue gas post-treatment system includes a waste heat recovery device and an SCR reactor, the flue gas duct of the oxidation furnace is connected to the waste heat recovery device, the flue gas duct of the waste heat recovery device is connected to the SCR reactor, and the SCR reactor is connected to the wastewater heat exchanger.

[0012] The above-mentioned method for treating wastewater by using a water-coal slurry coordinated wastewater treatment device comprises the following steps: S1. Turn on the induced draft fan of the wastewater and waste gas recovery and treatment system to form a slightly negative pressure state in the weighing coal feeder, coal grinding mechanism, and coal slurry boosting mechanism; S2. The wastewater is sent to the coal milling mechanism and the oxidation furnace system through the wastewater pipeline. The coal milling mechanism generates coal slurry mixed with wastewater, which is increased in pressure by the coal slurry boosting mechanism and then sent to the gasification furnace for combustion. The wastewater enters the oxidation furnace system and is burned together with the natural gas and waste gas. S3, the waste gas extracted from the coal grinding mechanism and the coal slurry boosting mechanism is respectively sent to the oxidation furnace system and the boiler fan through the waste gas pipeline; S4. The flue gas burned in the oxidation furnace system enters the flue gas post-treatment system for waste heat recovery and denitrification treatment.

[0013] Beneficial effects of the present invention: (1) The present invention adopts the above-mentioned device and method for the coordinated treatment of wastewater by water-coal slurry, and pumps the coal mill water tank, mill outlet drum screen, mill discharge tank and large coal slurry tank into a slightly negative pressure state through the exhaust pipeline, so that the entire gasification wastewater system is in a sealed negative pressure environment, effectively preventing the gas in the wastewater from diffusing into the surrounding atmosphere. The collected waste gas is finally discharged after high-temperature combustion and subsequent perfect flue gas treatment system, which greatly protects the on-site environment and the health of operators.

[0014] (2) The present invention adopts the above-mentioned device and method for the coordinated treatment of wastewater with water-coal slurry, and sends the wastewater from the pyridine device to the gasification furnace system and the oxidation furnace system for treatment. In the gasification furnace, the wastewater and coal slurry participate in the combustion reaction together, which helps to optimize the combustion process and improve the output and quality of synthesis gas; in the oxidation furnace, the combustion of wastewater and volatile waste gas also provides part of the energy for the oxidation furnace, reducing the use of fuels such as natural gas, which not only ensures the treatment volume of wastewater, but also greatly reduces energy costs. At the same time, the treatment of high-concentration organic wastewater basically does not increase production costs, and in the process of treating wastewater, it replaces part of the fresh water, which can save a large amount of industrial water every year, and the economic benefits are very obvious.

[0015] (3) The present invention adopts the above-mentioned device and method for the coordinated treatment of wastewater by water-coal slurry, which can make full use of organic wastewater. The organic wastewater is completely cracked at high temperature in the gasifier. After passing through the quenching chamber, the quenching speed is fast and no secondary pollution is generated. The H2, CO, CO2, H2S, etc. produced by the cracking are converted into liquid ammonia, liquid CO2, sulfuric acid and other products through subsequent transformation, low-methane, synthetic ammonia and other systems, and are comprehensively utilized as synthesis gas.

[0016] (4) The present invention adopts the above-mentioned device and method for the coordinated treatment of wastewater with water-coal slurry, which has a scientific and reasonable design, simple and practical structure, safe and reliable operation, and easy operation and use, and has extremely high promotion and application value.

[0017] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of a device for the coordinated treatment of wastewater by using water-coal slurry according to the present invention; Figure 2 It is a partial enlarged view of the coal slurry boosting mechanism of the present invention.

[0019] Reference numerals: 1. Gasifier system; 11. Weighing coal feeder; 12. Coal grinding mechanism; 121. Coal grinding water tank; 122. Grinding water pump; 123. Coal mill; 124. Fresh water pipeline; 125. Inlet chute; 126. Air extraction port 1; 13. Coal slurry boosting mechanism; 131. Drum screen; 132. Mill discharge trough; 133. Large coal slurry trough; 134. Low-pressure coal slurry pump; 135. High-pressure coal slurry pump; 136. Overflow pipe; 137. Check valve; 138. Air extraction port 2; 139. Air extraction port 3; 1310. Air extraction port 4; 14. Gasifier; 2. Wastewater and waste gas recovery and treatment system; 21. Wastewater pipeline; 22. Waste gas pipeline; 23. Induced draft fan; 24. Exhaust pipeline; 3. Oxidation furnace system; 31. Oxidation furnace; 32. Oxidation furnace blower; 33. Wastewater heat exchanger; 4. Boiler fan; 5. Flue gas post-treatment system; 51. Waste heat recovery device; 52. SCR reactor. DETAILED DESCRIPTION

[0020] The present invention is further described below in conjunction with the accompanying drawings and embodiments. Unless otherwise defined, the technical terms or scientific terms used in the present invention should be the common meanings understood by people with ordinary skills in the field to which the present invention belongs. The above-mentioned features or features mentioned in the specific examples mentioned in the present invention can be combined arbitrarily, and these specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0021] Example 1 Figure 1It is a schematic diagram of a device for the coordinated treatment of wastewater by water-coal slurry of the present invention. As shown in the figure, the present invention provides a device for the coordinated treatment of wastewater by water-coal slurry, including a gasifier system 1, a wastewater and waste gas recovery and treatment system 2 and an oxidation furnace system 3. The gasifier system 1 includes a weighing coal feeder 11, a coal grinding mechanism 12, a coal slurry boosting mechanism 13 and a gasifier 14 connected in sequence. The wastewater and waste gas recovery and treatment system 2 includes a wastewater pipeline 21, a waste gas pipeline 22, an induced draft fan 23 and an exhaust pipeline 24. The wastewater and waste gas recovery and treatment system 2 is connected to the gasifier system 1 and the oxidation furnace system 3 respectively. The wastewater in the wastewater pipeline 21 comes from the pyridine device and other wastewater. The wastewater is sent to the gasifier system 1 for combustion through the wastewater and waste gas recovery and treatment system 2, and the waste gas volatilized from the wastewater is sent to the oxidation furnace system 3 for combustion through the wastewater and waste gas recovery and treatment system 2, thereby realizing the recycling of wastewater, reducing the cost of wastewater treatment, and improving the economic benefits of wastewater treatment.

[0022] Figure 2 It is a partial enlarged view of the coal slurry boosting mechanism of the present invention. As shown in the figure, the coal grinding mechanism 12 includes a coal grinding water tank 121, a grinding water pump 122 and a coal mill 123. The water inlet of the coal grinding water tank 121 is connected to the fresh water pipeline 124 and the wastewater pipeline 21, and the water outlet of the coal grinding water tank 121 is connected to the inlet chute 125 of the coal mill 123 through the grinding water pump 122. The coal slurry boosting mechanism 13 includes a drum screen 131, a mill discharge trough 132 and a large coal slurry trough 133. The drum screen 131 is arranged at the outlet of the coal mill 123. The bottom of the drum screen 131 is connected to the mill discharge trough 132. The bottom of the mill discharge trough 132 is connected to the large coal slurry trough 133 through a low-pressure coal slurry pump 134. The bottom of the large coal slurry trough 133 is connected to the gasifier 14 through a high-pressure coal slurry pump 135.

[0023] The water inlet of the coal mill water tank 121 includes fresh water and waste water. As waste water is continuously added to the coal mill water tank 121, the fresh water decreases accordingly. The normal liquid level of the coal mill water tank 121 is maintained, and the amount of waste water entering is adjusted according to the coal slurry concentration and slurry characteristics to ensure the stable operation of the gasifier system 1. The water outlet of the coal mill water tank 121 enters the grinding water pump 122, and the grinding water pump 122 pumps the waste water into the inlet chute 125 of the coal mill 123. The waste water enters the coal mill 123 together with the coal dropped from the weighing coal feeder 11. The ground coal slurry passes through the drum screen 131 and enters the mill discharge trough 132. An overflow pipe 136 is also provided at the bottom of the drum screen 131, and a check valve 137 is provided on the overflow pipe 136. The check valve 137 is opened only when the material is dropped, and remains closed at other times. The coal slurry in the mill discharge trough 132 is sent to the large coal slurry tank 133 through the low-pressure coal slurry pump 134, and then sent to the burner of the gasifier 14 through the high-pressure coal slurry pump 135. The coal slurry mixed with wastewater enters the gasifier 14 together with oxygen and is burned, and the generated synthesis gas is sent to the synthetic ammonia device for treatment.

[0024] The top of the coal mill water tank 121 is provided with a suction port 126 connected to the suction pipeline 24, the top of the drum screen 131 is provided with a suction port 238 connected to the suction pipeline 24, the top of the mill discharge tank 132 is provided with a suction port 339 connected to the suction pipeline 24, and the top of the large coal slurry tank 133 is provided with a suction port 41310 connected to the suction pipeline 24. The suction pipeline 24 collects the waste gas generated by the waste water in the coal mill water tank 121, the drum screen 131, the mill discharge tank 132, and the large coal slurry tank 133. The exhaust pipeline 24 is connected to the exhaust gas pipeline 22 through the induced draft fan 23, and the exhaust gas pipeline 22 is respectively connected to the oxidation furnace system 3 and the boiler fan 4. The exhaust gas collected by the exhaust pipeline 24 enters the exhaust gas pipeline 22 through the induced draft fan 23, and then is sent to the boiler fan 4 and the oxidation furnace system 3 through the exhaust gas pipeline 22 for combustion treatment.

[0025] The oxidation furnace system 3 includes an oxidation furnace 31 and an oxidation furnace blower 32. The exhaust gas pipeline 22 is connected to the oxidation furnace 31 through the oxidation furnace blower 32. The waste water pipeline 21 is connected to the waste water heat exchanger 33. The waste water heat exchanger 33 is connected to the oxidation furnace 31. The oxidation furnace blower 32 delivers the exhaust gas transported by the exhaust gas pipeline 22 into the oxidation furnace 31. At the same time, the waste water in the waste water pipeline 21 is heated by the waste water heat exchanger 33 and then enters the nozzle of the oxidation furnace 31, and burns in the oxidation furnace 31 together with the natural gas and other exhaust gases.

[0026] The oxidation furnace system 3 is also connected to the flue gas post-treatment system 5, which includes a waste heat recovery device 51 and an SCR reactor 52. The flue gas pipeline of the oxidation furnace 31 is connected to the waste heat recovery device 51, and the flue gas pipeline of the waste heat recovery device 51 is connected to the SCR reactor 52, and the SCR reactor 52 is connected to the waste water heat exchanger 33. The flue gas generated by the oxidation furnace 31 enters the waste heat recovery device 51 for recycling, and the flue gas obtained by cooling in the waste heat recovery device 51 is then denitrated by the SCR reactor 52. The flue gas after denitration is further discharged from the chimney after passing through the waste water heat exchanger 33 to further recover the flue gas heat.

[0027] The present invention introduces the pyridine device and other wastewater into the wastewater pipeline 21, and sends them to the gasification furnace system 1 and the oxidation furnace system 3 for combustion treatment through the wastewater and waste gas recovery and treatment system 2, thereby realizing the resource utilization of wastewater. The wastewater that originally required a lot of cost to be treated now becomes part of the raw materials in the combustion process of the gasification furnace 14 and the oxidation furnace 31, avoiding the waste of resources, improving the comprehensive utilization rate of resources, reducing the dependence on external fresh water resources, and reducing the water cost of the enterprise.

[0028] Example 2 The method for treating wastewater by using a device for treating wastewater with water-coal slurry in Example 1 comprises the following steps: S1. Before the wastewater is fed into the gasification furnace system 1, the induced draft fan 23 of the wastewater and waste gas recovery and treatment system 2 is turned on to form a slightly negative pressure state in the weighing coal feeder 11, the coal grinding mechanism 12, and the coal slurry boosting mechanism 13; the section to which the waste gas is sent is selected according to the operation conditions of the oxidation furnace 31 and the boiler.

[0029] S2. The waste water is sent to the coal grinding mechanism 12 and the oxidation furnace system 3 respectively through the waste water pipeline 21. The coal grinding mechanism 12 generates coal slurry mixed with waste water, which is sent to the gasification furnace 14 for combustion treatment after the pressure is increased by the coal slurry boosting mechanism 13. After the waste water enters the oxidation furnace system 3, it is burned together with the natural gas and the waste gas. When the gasification furnace system 1 is operating normally, the digested waste water should reach the maximum amount, and the remaining waste water is sent to the oxidation furnace system 3 for treatment, so as to minimize the load of the oxidation furnace 31 and achieve maximum energy saving and consumption reduction.

[0030] The waste gas extracted from S3, the coal grinding mechanism 12 and the coal slurry boosting mechanism 13 is respectively sent to the oxidation furnace system 3 and the boiler fan 4 through the waste gas pipeline 22; the waste gas generated by the waste water in the coal grinding water tank 121, the drum screen 131, the mill discharge tank 132, and the large coal slurry tank 133 is extracted and finally sent to the oxidation furnace 31 or the boiler for combustion treatment.

[0031] S4. The flue gas burned in the oxidation furnace system 3 enters the flue gas post-treatment system 5 for waste heat recovery and denitrification treatment, and is finally discharged from the chimney.

[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A device for the coordinated treatment of wastewater by coal-water slurry, characterized in that: It includes a gasifier system, a wastewater and waste gas recovery and treatment system and an oxidation furnace system. The gasifier system includes a weighing coal feeder, a coal grinding mechanism, a coal slurry boosting mechanism and a gasifier which are connected in sequence. The wastewater and waste gas recovery and treatment system includes a wastewater pipeline, a waste gas pipeline, an induced draft fan and an exhaust pipeline. The wastewater pipeline is connected to the coal grinding mechanism and the oxidation furnace system respectively. The exhaust pipeline is connected to the coal grinding mechanism and the coal slurry boosting mechanism respectively. The exhaust pipeline is connected to the waste gas pipeline through the induced draft fan. The waste gas pipeline is connected to the oxidation furnace system and the boiler fan respectively. The oxidation furnace system is also connected to the flue gas post-treatment system.

2. The device for treating wastewater with coal water slurry according to claim 1, characterized in that: The coal grinding mechanism includes a coal grinding water tank, a grinding water pump and a coal grinding machine. The water inlet of the coal grinding water tank is connected with the fresh water pipeline and the waste water pipeline, and the water outlet of the coal grinding water tank is connected with the inlet chute of the coal grinding machine through the grinding water pump.

3. The device for treating wastewater with coal water slurry according to claim 2, characterized in that: The coal slurry boosting mechanism includes a drum screen, a mill discharge trough and a large coal slurry trough. The drum screen is arranged at the outlet of the coal mill. The bottom of the drum screen is connected to the mill discharge trough. The bottom of the mill discharge trough is connected to the large coal slurry trough through a low-pressure coal slurry pump. The bottom of the large coal slurry trough is connected to the gasifier through a high-pressure coal slurry pump.

4. The device for treating wastewater with coal water slurry according to claim 3, characterized in that: The top of the coal grinding water tank is provided with an exhaust port 1 connected to the exhaust pipeline, the top of the drum screen is provided with an exhaust port 2 connected to the exhaust pipeline, the top of the mill discharge trough is provided with an exhaust port 3 connected to the exhaust pipeline, and the top of the large coal slurry tank is provided with an exhaust port 4 connected to the exhaust pipeline.

5. The device for treating wastewater with coal water slurry according to claim 3, characterized in that: An overflow pipe is also provided at the bottom of the drum screen, and a check valve is provided on the overflow pipe.

6. The device for treating wastewater with coal water slurry according to claim 1, characterized in that: The oxidation furnace system comprises an oxidation furnace and an oxidation furnace blower, the exhaust gas pipeline is connected with the oxidation furnace through the oxidation furnace blower, the waste water pipeline is connected with the waste water heat exchanger, and the waste water heat exchanger is connected with the oxidation furnace.

7. The device for treating wastewater with coal water slurry according to claim 6, characterized in that: The flue gas post-treatment system includes a waste heat recovery device and an SCR reactor. The flue gas duct of the oxidation furnace is connected to the waste heat recovery device, the flue gas duct of the waste heat recovery device is connected to the SCR reactor, and the SCR reactor is connected to the wastewater heat exchanger.

8. A method for treating wastewater according to any one of claims 1 to 7 using a device for treating wastewater with water-coal slurry, characterized in that: The following steps are included: S1. Turn on the induced draft fan of the wastewater and waste gas recovery and treatment system to form a slightly negative pressure state in the weighing coal feeder, coal grinding mechanism, and coal slurry boosting mechanism; S2. The wastewater is sent to the coal milling mechanism and the oxidation furnace system through the wastewater pipeline. The coal milling mechanism generates coal slurry mixed with wastewater, which is increased in pressure by the coal slurry boosting mechanism and then sent to the gasification furnace for combustion. The wastewater enters the oxidation furnace system and is burned together with the natural gas and waste gas. S3, the waste gas extracted from the coal grinding mechanism and the coal slurry boosting mechanism is respectively sent to the oxidation furnace system and the boiler fan through the waste gas pipeline; S4. The flue gas burned in the oxidation furnace system enters the flue gas post-treatment system for waste heat recovery and denitrification treatment.

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