A device and method for co-disposing wastewater with coal water slurry

Abstract

This invention relates to the field of pressurized coal-water slurry gasification and wastewater treatment technology, and particularly to an apparatus and method for the co-treatment of wastewater using coal-water slurry. The apparatus includes a gasifier system, a wastewater and waste gas recovery and treatment system, and an oxidizer system. The gasifier system comprises a weighing feeder, a coal milling mechanism, a coal slurry pressurization mechanism, and the gasifier, 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 extraction pipeline. The wastewater pipeline is connected to both the coal milling mechanism and the oxidizer system. The extraction pipeline is connected to both the coal milling mechanism and the coal slurry pressurization mechanism. The extraction pipeline is connected to the waste gas pipeline via the induced draft fan. The waste gas pipeline is connected to both the oxidizer system and a boiler fan. The oxidizer system is also connected to a flue gas after-treatment system. This invention, employing the aforementioned apparatus and method for the co-treatment of wastewater using coal-water slurry, solves the safety, environmental protection, and cost issues in the treatment of high-concentration organic wastewater.

Description

Technical Field

[0001] This invention relates to the fields of pressurized gasification of coal-water slurry and wastewater treatment, and in particular to an apparatus and method for co-processing wastewater with coal-water slurry. Background Technology

[0002] With the continuous development of modern industry, the number of newly built and expanded projects by enterprises is increasing, leading to a year-on-year increase in wastewater generation and a corresponding surge in the pressure on wastewater treatment. Taking the production facilities of pyridine, hydrogen peroxide, and mesitylene as examples, the wastewater generated not only has extremely high organic content but also contains some toxic and harmful substances. Treating this type of wastewater is extremely difficult, and traditional wastewater treatment equipment often fails to achieve ideal results. Outsourcing treatment further exacerbates the problem with high costs. If the generated wastewater cannot be treated in a timely manner, the amount of wastewater temporarily stored within the factory area will increase, creating significant safety and environmental pressures. This could not only pose a potential threat to the surrounding environment but also expose the enterprise to environmental regulatory risks, affecting its normal production and operation.

[0003] Currently, common treatment processes for this type of organic wastewater include biological treatment, incineration, and oxidation. While biological treatment is widely used in wastewater treatment, its process is lengthy, its control procedures are complex, and it is more suitable for treating low-concentration wastewater. For high-concentration organic wastewater, biological treatment is ineffective, and treatment costs increase significantly. Incineration and oxidation methods oxidize hazardous waste under oxygen-rich conditions, making them suitable for treating hazardous waste with high organic content and high calorific value. However, they have significant drawbacks when treating wastewater; on the one hand, the process generates CO2 and NO. x The treatment of wastewater involves a variety of pollutants, such as smoke, dust, SO2, HCl, and dioxins, requiring corresponding secondary pollution control devices, which undoubtedly increases the treatment cost and technical difficulty. On the other hand, the treatment of wastewater consumes a large amount of natural gas, resulting in high energy consumption and high operating costs. Summary of the Invention

[0004] The purpose of this invention is to provide an apparatus and method for co-treating wastewater with coal-water slurry, which solves the safety, environmental protection and cost issues in the treatment of high-concentration organic wastewater.

[0005] To achieve the above objectives, the present invention provides an apparatus for co-processing wastewater from coal-water slurry, comprising a gasifier system, a wastewater and waste gas recovery and treatment system, and an oxidizer system. The gasifier system includes a weighing feeder, a coal milling mechanism, a coal slurry pressurization mechanism, and a gasifier 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 gas pipeline. The wastewater pipeline is connected to the coal milling mechanism and the oxidizer system, respectively. The exhaust gas pipeline is connected to the coal milling mechanism and the coal slurry pressurization mechanism, respectively. The exhaust gas pipeline is connected to the waste gas pipeline via the induced draft fan. The waste gas pipeline is connected to the oxidizer system and a boiler fan, respectively. The oxidizer system is also connected to a flue gas after-treatment system.

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

[0007] Preferably, the coal slurry pressurization mechanism includes a drum screen, a mill discharge trough, and a large coal slurry trough. The drum screen is located at the outlet of the coal mill, and 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, and 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 mill water tank is provided with an air extraction port one connected to the air extraction pipeline, the top of the drum screen is provided with an air extraction port two connected to the air extraction pipeline, the top of the mill discharge trough is provided with an air extraction port three connected to the air extraction pipeline, and the top of the large coal slurry tank is provided with an air extraction port four connected to the air extraction pipeline.

[0009] Preferably, the bottom of the drum screen is also equipped with an overflow pipe, and a check valve is installed on the overflow pipe.

[0010] Preferably, the oxidizer system includes an oxidizer and an oxidizer blower. The exhaust gas pipeline is connected to the oxidizer through the oxidizer blower, the wastewater pipeline is connected to the wastewater heat exchanger, and the wastewater heat exchanger is connected to the oxidizer.

[0011] Preferably, the flue gas aftertreatment system includes a waste heat recovery device and an SCR reactor. The flue gas duct of the oxidizer 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 wastewater treatment method of the above-mentioned coal-water slurry co-processing wastewater treatment device includes the following steps:

[0013] S1. Turn on the induced draft fan of the wastewater and waste gas recovery and treatment system to create a slightly negative pressure state for the weighing coal feeder, coal milling mechanism and coal slurry pressurization mechanism.

[0014] S2. Wastewater is sent to the coal mill and the oxidizer system through wastewater pipelines. The coal mill produces coal slurry mixed with wastewater. After the coal slurry is pressurized by the coal slurry pressurization mechanism, it is sent to the gasifier for combustion. After the wastewater enters the oxidizer system, it is burned together with natural gas and waste gas.

[0015] S3. The exhaust gas extracted from the coal milling mechanism and the coal slurry pressurization mechanism is sent to the oxidation furnace system and the boiler fan through exhaust gas pipelines respectively.

[0016] S4. The flue gas from the combustion of the oxidation furnace system enters the flue gas post-treatment system for waste heat recovery and denitrification.

[0017] The beneficial effects of this invention are:

[0018] (1) The present invention employs the above-mentioned apparatus and method for co-processing wastewater with coal-water slurry. Through an extraction pipeline, the coal mill water tank, the mill outlet drum screen, the mill discharge trough, and the large coal slurry tank are drawn into a slightly negative pressure state, ensuring 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 ultimately discharged after high-temperature combustion and a subsequent improved flue gas treatment system, greatly protecting the on-site environment and the health of operators.

[0019] (2) The present invention employs the above-mentioned apparatus and method for co-treating wastewater with coal-water slurry. The wastewater from the pyridine plant is sent 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 yield and quality of syngas. In the oxidation furnace, the combustion of wastewater and volatile waste gas also provides some energy for the oxidation furnace, reducing the use of fuels such as natural gas. This not only ensures the treatment volume of wastewater but also significantly reduces energy costs. At the same time, the treatment of high-concentration organic wastewater does not increase production costs, and it replaces some fresh water in the process of treating wastewater, saving a large amount of industrial water every year, resulting in significant economic benefits.

[0020] (3) The present invention uses the above-mentioned device and method for co-processing wastewater with coal-water 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 quench chamber, the quenching speed is fast and no secondary pollution is generated. The H2, CO, CO2, H2S, etc. generated by cracking are used to generate liquid ammonia, liquid CO2, sulfuric acid and other products through subsequent conversion, low-methane, and ammonia synthesis systems, which are then used as syngas for comprehensive utilization.

[0021] (4) The present invention adopts the above-mentioned device and method for co-processing wastewater with coal-water slurry. The design is scientific and reasonable, the structure is simple and practical, the operation is safe and reliable, and the operation is convenient. It has extremely high promotion and application value.

[0022] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a device for co-processing wastewater with coal-water slurry according to the present invention;

[0024] Figure 2 This is a partially enlarged view of the coal slurry pressurization mechanism of the present invention.

[0025] Figure label:

[0026] 1. Gasification furnace system;

[0027] 11. Weighing coal feeder;

[0028] 12. Coal grinding mechanism; 121. Coal grinding water tank; 122. Grinding water pump; 123. Coal mill; 124. Fresh water pipeline; 125. Inlet chute; 126. Exhaust port 1;

[0029] 13. Coal slurry pressurization mechanism; 131. Rotary drum screen; 132. Mill discharge chute; 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 two; 139. Air extraction port three; 1310. Air extraction port four;

[0030] 14. Gasification furnace;

[0031] 2. Wastewater and exhaust gas recovery and treatment system; 21. Wastewater pipeline; 22. Exhaust gas pipeline; 23. Exhaust fan; 24. Exhaust gas pipeline;

[0032] 3. Oxidation furnace system; 31. Oxidation furnace; 32. Oxidation furnace blower; 33. Wastewater heat exchanger;

[0033] 4. Boiler fan;

[0034] 5. Flue gas after-treatment system; 51. Waste heat recovery device; 52. SCR reactor. Detailed Implementation

[0035] The present invention will be further described below with reference to the accompanying drawings and embodiments. Unless otherwise defined, the technical or scientific terms used in this invention should be understood in their ordinary sense by those skilled in the art. The features mentioned above or in the specific examples mentioned in this invention can be combined arbitrarily, and these specific embodiments are only used to illustrate the invention and are not intended to limit the scope of the invention.

[0036] Example 1

[0037] Figure 1This is a schematic diagram of an apparatus for co-processing wastewater with coal-water slurry according to the present invention. As shown in the figure, the present invention provides an apparatus for co-processing wastewater with coal-water slurry, including a gasifier system 1, a wastewater and waste gas recovery and treatment system 2, and an oxidizer system 3. The gasifier system 1 includes a weighing coal feeder 11, a coal milling mechanism 12, a coal slurry pressurization 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 gas pipeline 24. The wastewater and waste gas recovery and treatment system 2 is connected to both the gasifier system 1 and the oxidizer system 3. 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 via the wastewater and waste gas recovery and treatment system 2. The waste gas volatilized from the wastewater is sent to the oxidizer system 3 for combustion via 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 efficiency of wastewater treatment.

[0038] Figure 2 This is a partially enlarged view of the coal slurry pressurization 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 inlet of the coal grinding water tank 121 is connected to the fresh water pipeline 124 and the wastewater pipeline 21, and the 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 pressurization mechanism 13 includes a drum screen 131, a mill discharge trough 132, and a large coal slurry tank 133. The drum screen 131 is located at the outlet of the coal mill 123, and 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 tank 133 through a low-pressure coal slurry pump 134, and the bottom of the large coal slurry tank 133 is connected to the gasifier 14 through a high-pressure coal slurry pump 135.

[0039] The inlet water of the coal pulverizing tank 121 includes both fresh water and wastewater. As wastewater is continuously added to the coal pulverizing tank 121, the amount of fresh water decreases accordingly, maintaining the normal liquid level of the coal pulverizing tank 121. The amount of wastewater entering is adjusted according to the coal slurry concentration and slurry formation characteristics to ensure the stable operation of the gasifier system 1. The effluent from the coal pulverizing tank 121 enters the grinding water pump 122, which pumps the wastewater into the inlet chute 125 of the coal mill 123. The wastewater, along with the coal falling from the weighing feeder 11, enters the coal mill 123. The ground coal slurry passes through the drum screen 131 and then enters the mill discharge chute 132. The bottom of the drum screen 131 is also equipped with an overflow pipe 136, and a check valve 137 is provided on the overflow pipe 136. The check valve 137 is only opened when the material is discharged and is kept closed at other times. The coal slurry from the mill discharge trough 132 is sent to the large coal slurry trough 133 after passing 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 for combustion along with oxygen, and the generated syngas is sent to the ammonia synthesis unit for treatment.

[0040] The top of the coal pulverizing water tank 121 is equipped with an exhaust port 126 connected to the exhaust pipeline 24; the top of the drum screen 131 is equipped with an exhaust port 138 connected to the exhaust pipeline 24; the top of the mill discharge trough 132 is equipped with an exhaust port 139 connected to the exhaust pipeline 24; and the top of the large coal slurry tank 133 is equipped with an exhaust port 1310 connected to the exhaust pipeline 24. The exhaust pipeline 24 collects the waste gas generated from the wastewater in the coal pulverizing water tank 121, drum screen 131, mill discharge trough 132, and large coal slurry tank 133. The exhaust pipe 24 is connected to the waste gas pipe 22 via the induced draft fan 23. The waste gas pipe 22 is connected to the oxidizer system 3 and the boiler fan 4 respectively. The waste gas collected by the exhaust pipe 24 enters the waste gas pipe 22 via the induced draft fan 23, and then is sent to the boiler fan 4 and the oxidizer system 3 respectively for combustion treatment.

[0041] The oxidizer system 3 includes an oxidizer 31 and an oxidizer blower 32. The exhaust gas pipeline 22 is connected to the oxidizer 31 via the oxidizer blower 32, and the wastewater pipeline 21 is connected to the wastewater heat exchanger 33, which in turn is connected to the oxidizer 31. The oxidizer blower 32 delivers the exhaust gas from the exhaust gas pipeline 22 into the oxidizer 31. Simultaneously, the wastewater from the wastewater pipeline 21 is heated by the wastewater heat exchanger 33 and then enters the oxidizer 31 through the nozzles, where it is burned together with natural gas and other exhaust gases within the oxidizer 31.

[0042] The oxidizer system 3 is also connected to the flue gas after-treatment system 5, which includes a waste heat recovery device 51 and an SCR reactor 52. The flue gas duct of the oxidizer 31 is connected to the waste heat recovery device 51, the flue gas duct of the waste heat recovery device 51 is connected to the SCR reactor 52, and the SCR reactor 52 is connected to the wastewater heat exchanger 33. The flue gas generated by the oxidizer 31 enters the waste heat recovery device 51 for recovery and utilization. The flue gas cooled in the waste heat recovery device 51 is then denitrified by the SCR reactor 52. After denitrification, the flue gas is further denitrified by the wastewater heat exchanger 33 before being vented through the chimney.

[0043] This invention introduces pyridine equipment and other wastewater into wastewater pipeline 21, which is then fed into gasification furnace system 1 and oxidation furnace system 3 for combustion treatment via wastewater and waste gas recovery and treatment system 2, thus realizing the resource utilization of wastewater. Wastewater that previously required costly treatment now becomes part of the raw material in the combustion process of gasification furnace 14 and oxidation furnace 31, avoiding resource waste, improving the comprehensive utilization rate of resources, reducing dependence on external fresh water resources, and lowering the company's water costs.

[0044] Example 2

[0045] Example 1 describes a wastewater treatment method using a coal-water slurry co-treatment device, comprising the following steps:

[0046] S1. Before the wastewater is sent into the gasifier system 1, the induced draft fan 23 of the wastewater and waste gas recovery and treatment system 2 is turned on, so that the weighing coal feeder 11, the coal milling mechanism 12, and the coal slurry pressurization mechanism 13 form a slightly negative pressure state; the waste gas is sent to which section according to the operation of the oxidizer 31 and the boiler.

[0047] S2. Wastewater is sent to the coal mill 12 and the oxidizer system 3 through the wastewater pipeline 21. The coal mill 12 produces coal slurry mixed with wastewater. After the coal slurry pressurization mechanism 13 increases the pressure, it is sent to the gasifier 14 for combustion. The wastewater enters the oxidizer system 3 and is burned together with natural gas and exhaust gas. When the gasifier system 1 is operating normally, the amount of wastewater digested should reach the maximum. The remaining wastewater is then sent to the oxidizer system 3 for treatment to minimize the load on the oxidizer 31 and achieve maximum energy saving and consumption reduction.

[0048] The exhaust gas extracted from the coal milling mechanism 12 and the coal slurry pressurization mechanism 13 is sent to the oxidizer system 3 and the boiler fan 4 respectively through the exhaust gas pipeline 22; the exhaust gas generated from the wastewater in the coal mill 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 oxidizer 31 or the boiler for combustion treatment.

[0049] S4. The flue gas from the combustion of the oxidizer system 3 enters the flue gas post-treatment system 5 for waste heat recovery and denitrification treatment, and is finally vented from the chimney.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. An apparatus for co-treating wastewater with coal-water slurry, characterized in that: It includes a gasifier system, a wastewater and waste gas recovery and treatment system, and an oxidizer system. The gasifier system includes a weighing coal feeder, a coal milling mechanism, a coal slurry pressurization mechanism, and a gasifier connected in sequence. The wastewater and waste gas recovery and treatment system includes wastewater pipelines, waste gas pipelines, an induced draft fan, and an exhaust gas pipeline. The wastewater pipelines are connected to the coal milling mechanism and the oxidizer system, respectively. The exhaust gas pipelines are connected to the coal milling mechanism and the coal slurry pressurization mechanism, respectively. The exhaust gas pipelines are connected to the waste gas pipelines through the induced draft fan, respectively. The waste gas pipelines are connected to the oxidizer system and the boiler fan, respectively. The oxidizer system is also connected to the flue gas after-treatment system. 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, and the wastewater pipeline is connected to the wastewater heat exchanger. The wastewater heat exchanger is connected to the oxidation furnace. The wastewater treatment method of the above-mentioned coal-water slurry co-processing wastewater treatment device includes the following steps: S1. Turn on the induced draft fan of the wastewater and waste gas recovery and treatment system to create a slightly negative pressure state for the weighing coal feeder, coal milling mechanism and coal slurry pressurization mechanism. S2. Wastewater is sent to the coal mill and oxidizer system through wastewater pipelines. The coal mill produces coal slurry mixed with wastewater, which is then pressurized by the coal slurry pressurization mechanism and sent to the gasifier for combustion. The exhaust gas extracted from the coal mill and coal slurry pressurization mechanism is sent to the oxidizer system and boiler fan through exhaust gas pipelines. Wastewater enters the oxidizer system and is burned together with natural gas and exhaust gas. S3. The flue gas from the combustion of the oxidation furnace system enters the flue gas post-treatment system for waste heat recovery and denitrification.

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

3. The apparatus for co-treating wastewater with coal-water slurry according to claim 2, characterized in that: The coal slurry pressurization mechanism includes a rotary screen, a mill discharge chute, and a large coal slurry trough. The rotary screen is located at the outlet of the coal mill, and its bottom is connected to the mill discharge chute. The bottom of the mill discharge chute is connected to the large coal slurry trough via a low-pressure coal slurry pump, and the bottom of the large coal slurry trough is connected to the gasifier via a high-pressure coal slurry pump.

4. The apparatus for co-treating wastewater with coal-water slurry according to claim 3, characterized in that: The top of the coal mill water tank is equipped with an air extraction port 1 connected to the air extraction pipeline; the top of the drum screen is equipped with an air extraction port 2 connected to the air extraction pipeline; the top of the mill discharge trough is equipped with an air extraction port 3 connected to the air extraction pipeline; and the top of the large coal slurry tank is equipped with an air extraction port 4 connected to the air extraction pipeline.

5. The apparatus for co-treating wastewater with coal-water slurry according to claim 3, characterized in that: The bottom of the drum screen is also equipped with an overflow pipe, and a check valve is installed on the overflow pipe.

6. The apparatus for co-treating wastewater with coal-water slurry according to claim 1, characterized in that: The flue gas aftertreatment system includes a waste heat recovery device and an SCR reactor. The flue gas duct of the oxidizer 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.

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