A coal gasification system and method for treating organic waste liquid

Abstract

The invention discloses a coal gasification system and method for treating organic waste liquid, the gasification system comprising a gasifier, an organic waste liquid unit and a boiler water unit; the gasifier comprises a gasification chamber, a cooling chamber located below the gasification chamber and a slag lowering port connecting the gasification chamber and the cooling chamber, and a burner portion is provided on the top of the gasification chamber; the burner portion comprises a burner seat fixed to a furnace body, an ignition burner arranged at the center of the burner seat and a plurality of process burners uniformly arranged around the ignition burner; the process burner is provided with an oxygen channel, a coal powder channel, a liquid channel and a cooling water jacket in sequence from the inside to the outside; the feed port of the liquid channel is respectively connected to the boiler water unit, the organic waste liquid unit and the inert gas source through pipelines; the invention simplifies the pulverized coal gasification process, realizes water / organic waste liquid as an auxiliary gasifying agent, and treats and converts organic matter in the waste liquid, taking into account both environmental protection and recycling.

Description

Technical Field

[0001] The invention relates to the field of coal gasification, in particular to a coal gasification system and method for treating organic waste liquid. Background Art

[0002] my country's energy and resource consumption is mainly coal. Many chemicals are produced and manufactured through coal conversion. The source of these conversions is to use coal gasification technology to convert coal into synthesis gas mainly composed of carbon monoxide and hydrogen, and then further synthesize and manufacture downstream chemicals or fuels. Dry powder coal fluidized flow pressurized gasification technology has been widely used by domestic coal chemical plants due to its advantages in gasification efficiency. This technology is to grind and dry the raw coal into small particles of coal powder, which are then transported to the gasifier through pneumatic dense phase for gasification reaction with oxygen. The coal conversion rate can reach more than 99%, the effective gas content is 87-93%, the cold gas efficiency is 79-83%, and the oxygen consumption and coal consumption per unit product are low.

[0003] However, when using the above-mentioned gasification technology, in order to achieve heat balance and temperature balance in the gasifier, a certain amount of water vapor needs to be added (as an auxiliary gasification agent to participate in the reaction), especially for raw coal with high carbon content and high calorific value such as anthracite and coke powder, the amount of steam added during gasification will be higher. The pressure of pulverized coal gasification is generally around 4.0MPaG, and the water vapor is added by superheating 5.0-5.5MPaG saturated steam (~300℃) and mixing it with oxygen, and then entering the burner in the form of mixed gas (in order to prevent water vapor condensation from damaging the equipment, oxygen also needs to be heated to above 160℃).

[0004] However, most chemical companies do not have medium-pressure steam of ~5.0MPaG (self-built power plants are not allowed). It is difficult to obtain superheated steam, and high-pressure steam must be used to obtain it through temperature and pressure reduction, which complicates the process and increases investment. In addition, oxygen is a high-risk gas, and water vapor and oxygen need to be absolutely clean when mixed. Even trace impurities may cause safety accidents such as explosion. In addition, affected by the temperature of water vapor and oxygen, the sealing and material selection requirements of the equipment, pipelines and instruments of the oxygen system are increased, and the investment cost and maintenance cost of the device are increased accordingly. In particular, from the oxygen steam mixing point to the burner, the pipelines and equipment on the pipelines must use high-alloy, extremely low-carbon nickel-based materials, which are extremely expensive and difficult to process, bringing great burdens to the device in terms of cost and construction period. Therefore, canceling the mixing system before oxygen and water vapor enter the burner and considering directly feeding in the form of liquid water can effectively improve the safety of the device, simplify the process flow, and reduce the investment in devices and equipment. In addition, considering that coal chemical plants often have some high COD organic waste liquid, it is difficult to treat and the treatment cost is high. For example, a large amount of toxic waste water (also called tar waste water) is produced during the coal tar processing. The waste water contains high concentrations of organic matter, complex components, and is difficult to treat. The water in the organic waste liquid can participate in the reaction as an auxiliary gasification agent, and the organic matter in the waste liquid is burned and treated under the high temperature environment of the gasifier, which can reduce environmental pollution. At the same time, the multi-carbon organic matter is decomposed into small molecular substances mainly composed of CO, H2, CO2, etc., which is not only easy to handle in the later stage, but also can be converted into synthesis gas to improve economic benefits.

[0005] Therefore, in view of the shortcomings and disadvantages of the above-mentioned gasification principle and existing gasification systems, it is very necessary to develop a pulverized coal gasification system that eliminates the oxygen and water vapor mixing system and instead uses oxygen and water / organic waste liquid direct feeding, which can not only simplify the process and reduce investment, but also treat organic waste liquid, reduce pollution and create added value. Summary of the invention

[0006] The purpose of the present invention is to provide a coal gasification system for treating organic waste liquid, simplify the pulverized coal gasification process, realize water / organic waste liquid as an auxiliary gasification agent and treat and transform organic matter in the waste liquid, taking into account environmental protection and recycling.

[0007] In order to achieve the above-mentioned invention object, the present invention adopts the following technical scheme:

[0008] A coal gasification system for treating organic waste liquid, wherein the gasification system comprises a gasifier, an organic waste liquid unit and a boiler water unit; the gasifier comprises a gasification chamber separated by a water-cooled wall in a furnace body, a cooling chamber located below the gasification chamber and a slag lowering port connecting the gasification chamber and the cooling chamber, and a burner is provided on the top of the gasification chamber; the cooling chamber is used to cool down the gasification product from the slag lowering port;

[0009] The burner portion comprises a burner seat fixed to the furnace body, an ignition burner arranged at the center of the burner seat, and a plurality of process burners uniformly arranged on the burner seat around the ignition burner;

[0010] The process burner is used to feed gasification raw materials into the gasification chamber so as to carry out gasification reaction in the gasification chamber. The process burner is provided with an oxygen channel, a coal powder channel, a liquid channel and a cooling water jacket from the inside to the outside.

[0011] The feed port of the liquid channel is connected to the boiler water unit, the organic waste liquid unit and the inert gas source through pipelines, so as to receive boiler water from the boiler water unit, organic waste liquid from the organic waste liquid unit and inert gas; the boiler water unit is also provided with a pipeline for providing cooling water to the water-cooled wall and the burner cooling water jacket.

[0012] In one embodiment of the present invention, the organic waste liquid unit includes an organic waste liquid storage tank, a filter for filtering the organic waste liquid to be introduced into the organic waste liquid storage tank, a viscometer for measuring the organic waste liquid from the organic waste liquid storage tank, and a waste liquid delivery pump for delivering the organic waste liquid after viscosity measurement into the liquid phase channel.

[0013] In one embodiment of the present invention, the boiler unit comprises:

[0014] A waste heat boiler, used to recover heat from boiler water of the water-cooled wall to produce steam as a by-product;

[0015] A boiler water storage tank for receiving boiler water after heat recovery from outside the limit area and the waste heat boiler; and

[0016] A boiler water pump is used to deliver the boiler water in the boiler water storage tank into the liquid phase channel and as cooling water into the water-cooled wall and the burner cooling water jacket.

[0017] In one embodiment of the present invention, the number of process burners is 3 to 6; there is a certain angle between the process burner and the axial direction of the gasifier so that the head of the process burner is inclined toward the center of the gasification chamber of the gasifier, and the angle is 0-15. Those skilled in the art can understand that when the angle is 0°, the process burner is arranged parallel to the axial direction of the gasifier.

[0018] In one embodiment of the present invention, the burner heads of the oxygen channel and the pulverized coal channel are both provided with swirlers so that oxygen and pulverized coal are ejected from the burner heads at certain tangential and axial speeds; the burner head of the liquid phase channel is provided with an injector so that the liquid phase is broken up and atomized and then injected into the gasifier.

[0019] In one embodiment of the present invention, a downcomer and a quenching ring arranged at the upper end of the downcomer are provided in the cooling chamber, wherein the downcomer is used to introduce the gasification product from the lower slag port into the lower water bath of the quenching chamber for cooling and washing, and the quenching ring is used to spray quenching water to protect the downcomer.

[0020] In one embodiment of the present invention, the ignition burner is provided with a fuel gas channel, an oxygen channel and a cooling water jacket in sequence from the inside to the outside, wherein an igniter and a flame detector are also provided in the fuel gas channel.

[0021] In one embodiment of the present invention, the water-cooled wall is a spiral coil type or a shell and tube type water-cooled wall, which is provided with a water-cooled wall fireproof lining on the fire side; the cooling water jackets of the ignition burner and the process burner are both provided with pipelines connected to the boiler water pump to receive cooling water.

[0022] The present invention further provides a method for treating organic waste liquid using the above-mentioned coal gasification system, wherein the organic waste liquid is sprayed into the gasification chamber through the liquid phase channel for treatment.

[0023] In one embodiment of the present invention, when ignition is started, oxygen and fuel gas are introduced through the ignition burner at the top center of the gasifier, and ignition is ignited by high voltage discharge at the head of the igniter, and then the ignition state is determined by the flame detector. After ignition is determined, the flow rate of oxygen and fuel gas is increased to increase the temperature in the furnace;

[0024] After the ignition is successful and the oxygen and fuel gas flow rates meet the specified requirements, the pulverized coal and oxygen are gradually fed into the gasifier through the process burner;

[0025] After the pulverized coal and oxygen of the corresponding process burner are put into operation and the operation is stable, the liquid phase channel is switched from inert gas to organic waste liquid, and then the flow rate and ratio of oxygen, pulverized coal and water / organic waste liquid of the process burner are adjusted to achieve good gasification efficiency in the furnace;

[0026] After the process burner is charged, the flow rate and heat load of oxygen and fuel gas of the ignition burner are reduced to continue to be used as a permanent lamp, or inert gas is introduced into the oxygen and fuel gas channels of the ignition burner for positive pressure sealing protection.

[0027] In one embodiment of the method of the present invention, when the organic waste liquid feed of the process burner is insufficient, part of the boiler water is fed into the liquid phase channel by valve switching to replace part of the organic waste liquid, thereby forming a common feed of boiler water and organic waste liquid;

[0028] When the supply of organic waste liquid stops, boiler water is used to completely replace the organic waste liquid and sent into the liquid phase channel to ensure the water content in the feed of the process burner, thereby ensuring the gasification effect;

[0029] When the gasifier is in an unstable state or is about to be shut down, the feed in the liquid phase channel is switched to an inert gas feed to perform positive pressure sealing protection, that is, to prevent the material in the gasification chamber from entering the liquid phase channel.

[0030] In one embodiment, the organic wastewater is tar wastewater.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. The invention has the characteristics of high efficiency of dry coal powder gasification, eliminates the oxygen heating system, steam pressure reduction and filtration system, and oxygen-steam mixing system, and uses low-temperature water / organic waste liquid for direct feeding, simplifies the process, reduces equipment, and reduces the material requirements for corresponding oxygen system equipment and pipelines, thereby greatly reducing engineering construction costs and improving the safety of the device (reduced oxygen temperature).

[0033] 2. The gasification system adopts a top-mounted multi-nozzle downward spraying structure, which has good mixing and back-mixing effects in the furnace, and uniform distribution of flow field and temperature field in the furnace. Water / organic waste liquid is directly sprayed into the high-temperature flame center area of ​​the gasification chamber in the form of high-speed tiny droplets through the injection and atomization device, which can ensure its high treatment effect with high gasification efficiency and low raw material consumption.

[0034] 3. For dry powder gasification, in order to ensure the stability of coal powder transportation, the water content in the coal powder needs to be controlled within a certain range, but when the gasifier is running, a certain amount of water vapor needs to be added to the gasifier to maintain the temperature and heat balance inside the gasifier. In this patent, organic waste liquid is introduced into the gasifier, which can not only meet the original process requirements but also treat the organic waste liquid in the factory, which can protect the environment, reduce wastewater treatment investment and treatment costs, and create economic benefits and added value through recycling.

[0035] 4. Storage, transportation and addition systems for water feed and organic waste liquid are set up at the same time. The water feed uses the boiler water circulation pump of the original water-cooled wall and burner cooling water system in the gasification device. The process is simple and no additional equipment is added; the organic waste liquid feed is an independent system. During operation, both organic waste liquid and water can be fed independently, and water and organic waste liquid can be fed as a mixed feed, ensuring that the gasifier can still operate efficiently and stably when the supply of organic waste liquid is abnormal.

[0036] 5. Through the design of the burner adopted in this patent, the gasification device that has been in operation can be upgraded by adding corresponding equipment to achieve the treatment of organic waste liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1A schematic diagram of an embodiment of a coal gasification system of the present invention;

[0038] Figure 2 is a cross-sectional schematic diagram of the process burner;

[0039] Among them, 10-gasifier, 11-gasification chamber, 12-cooling chamber, 13-slag outlet, 14-burner seat, 15-ignition burner, 16'-a plurality of process burner collection, 16-process burner, 18-down pipe, 19-quenching ring, 21-boiler water storage tank, 22-waste heat boiler, 23-boiler water pump, 31-organic waste liquid storage tank, 32-filter, 33-waste liquid delivery pump, 34-viscometer, 161-oxygen channel, 162-oxygen inlet, 163-coal powder inlet, 164-coal powder channel, 165-liquid phase channel, 166-liquid phase inlet, 167-process burner cooling water jacket, 168-burner cooling water inlet, 169-burner cooling water outlet, 170-coal powder cyclone, 171-oxygen cyclone, 172-injector. DETAILED DESCRIPTION

[0040] The technical scheme and its effects of the present invention are further described below through specific implementation methods. The following implementation methods are only used to illustrate the content of the present invention, and the invention is not limited to the following implementation methods or examples. Simple changes made to the present invention using the concept of the present invention are all within the scope of protection claimed by the present invention.

[0041] like Figure 1-2 As shown, the coal gasification system of the present invention comprises a gasifier 10, an organic waste liquid unit and a boiler water unit; the gasifier 1 comprises a gasification chamber 11 separated by a water-cooled wall 17 in a furnace body, a cooling chamber 12 located below the gasification chamber 11 and a lower slag port 13 connecting the gasification chamber 11 and the cooling chamber 12, and a burner portion is provided at the top of the gasification chamber 11;

[0042] The burner portion includes a burner seat 14 fixed to the furnace body, an ignition burner 15 arranged at the center of the burner seat 14, and a plurality of process burners uniformly arranged on the burner seat 14 around the ignition burner 15 (see Figure 1 16', however, to simplify the drawings, Figure 1 Only one process burner is shown, for example 3 to 6 (such as Figure 1 The process burner 16 is arranged parallel to the axial direction of the gasifier 10 (as shown in FIG. Figure 1 ), or the head of the process burner 16 (ie, the fire end) is tilted toward the center of the gasification chamber 11 of the gasifier, and the angle is 0-15° (excluding 0°).

[0043] The process burner 16 is used to feed gasification raw materials into the gasification chamber 11 so as to carry out a gasification reaction in the gasification chamber 11. The process burner 16 is provided with an oxygen channel 161, a coal powder channel 164, a liquid channel 165 and a cooling water jacket 167 from the inside to the outside; wherein, the feed port 166 of the liquid channel 165 is respectively connected to the boiler water unit, the organic waste liquid unit and the inert gas source through pipelines to receive boiler water from the boiler water unit, organic waste liquid from the organic waste liquid unit and inert gas.

[0044] The burner head of the oxygen channel 161 of the process burner 16 is provided with an oxygen cyclone 171, so that oxygen is ejected from the burner head at a certain tangential and axial speed; the burner head of the pulverized coal channel 164 is provided with a pulverized coal cyclone 170, so that pulverized coal is ejected from the burner head at a certain tangential and axial speed; the burner head of the liquid phase channel 165 is provided with a water / organic waste liquid injector 172, so that the liquid phase is broken up and then injected into the gasifier 10, wherein water and organic waste liquid can be fed separately or mixed in a certain proportion. After leaving the burner head, the pulverized coal and oxygen are cut, swirled and uniformly mixed through their tangential and axial speeds, thereby improving the gasification efficiency of the pulverized coal in the high temperature environment of the furnace and the uniform slag in the gasifier; after the water / organic waste liquid is broken up and atomized, it is ejected in the form of droplets, accelerating the vaporization (evaporation) speed, and increasing the speed of its gasification reaction with pulverized coal, oxygen and synthesis gas in the central flame area.

[0045] The organic waste liquid unit includes an organic waste liquid storage tank 31, a filter 32 for filtering the organic waste liquid to be entered into the organic waste liquid storage tank 31, a viscometer 34 for measuring the organic waste liquid from the organic waste liquid storage tank 31, and a waste liquid delivery pump 33 for delivering the organic waste liquid after the viscosity is measured into the liquid phase channel 165. The viscosity of the organic waste liquid is measured online by the viscometer 34. When the viscosity value exceeds the specified value, the organic waste liquid feeding is stopped by interlocking, and the liquid phase channel 165 of the process burner 16 is changed to water operation or inert gas for positive pressure protection to prevent the high-temperature synthesis gas from flowing back. The organic waste liquid unit can also include a flow meter and a flow regulating valve. The flow setting value is given according to the operation load, operation load, operating temperature, and coal quality of the gasifier. By comparing the setting value with the measured value of the flow meter, the flow regulating valve is automatically adjusted to control the flow of the organic waste liquid entering the process burner.

[0046] The boiler water unit is also provided with a pipeline for providing cooling water for the water-cooled wall 17 and the burner cooling water jacket. The boiler unit includes a waste heat boiler 22, a boiler water storage tank 21 and a boiler water pump 23, wherein the waste heat boiler 22 is used to recover heat from the boiler water of the water-cooled wall 17 to produce steam as a by-product; the boiler water storage tank 21 is used to receive boiler water after heat recovery from outside the boundary area and the waste heat boiler 22; the boiler water pump 23 is used to send the boiler water in the boiler water storage tank 21 into the liquid phase channel 165 and into the water-cooled wall 17 as cooling water. At the same time, the cooling water jackets 167 of the ignition burner 15 and the process burner 16 are both provided with pipelines connected to the boiler water pump 23 to receive cooling water from the boiler water pump 23 to cool the burner head and prevent the burner head from being damaged by long-term high temperature.

[0047] The ignition burner 15 is provided with a fuel gas channel, an oxygen channel and a cooling water jacket (not shown in the figure) from the inside to the outside, wherein an igniter and a flame detector are also provided in the fuel gas channel. In one embodiment, the ignition burner is located at the center of the top of the gasifier, vertically inserted into the gasifier, and the head is flush with the burner seat. Oxygen and fuel gas enter the gasifier through different inlets and internal channels on the burner, respectively. The igniter and the flame detector are installed on the ignition burner as auxiliary devices. During ignition, a small amount of oxygen and fuel gas are introduced into the gasifier, and the fuel gas and oxygen ejected from the head of the ignition burner are ignited by the ignition gun that penetrates into the head of the burner. The flame detector automatically determines whether the fuel gas and oxygen in the furnace are ignited; after determining that the ignition is successful, the oxygen and fuel gas flow rates are increased, and the combustion intensity and heat load in the furnace are increased to the specified requirements before the process burner can be fed. After the process burner is successfully fed, the ignition burner can reduce the flow rate and continue to pass oxygen and fuel gas for use, or inert gas can be passed into the oxygen and fuel gas channels for positive pressure sealing protection.

[0048] The cooling chamber 12 is used to cool the gasification product from the lower slag port 13, and can be a full water quenching type, a waste boiler type, or a water quenching + waste boiler type. Figure 1 and 2 As shown, the cooling chamber adopts a full water quenching type, and is provided with a down pipe 18 and a quenching ring 19 arranged at the upper end of the down pipe 18, wherein the down pipe 18 is used to introduce the gasification product from the lower slag port 13 into the lower water bath of the cooling chamber 12 for cooling and washing, and the quenching ring 19 is used to spray quenching water to protect the down pipe 18.

[0049] Of course, those skilled in the art will appreciate that the coal gasification system may also include other instruments, valves, pumps, etc., and the configuration of these devices may be determined by those skilled in the art according to actual needs, and will not be elaborated herein.

[0050] The working mode of this equipment system is as follows:

[0051] In the gasification chamber of the gasifier, oxygen, coal powder, water / organic waste liquid react and are converted into synthesis gas (the multi-carbon organic matter in the organic waste liquid is decomposed into CO, CO2, H2, H2S, N2, NH3, HCN and other small molecular substances or gases at high temperature) and sent to the downstream device as a product after being cooled in the quenching chamber. The gasification temperature is 1400-1700℃ and the gasification pressure is 2.0-4.5MPaG.

[0052] When ignition is started, oxygen and fuel gas are introduced into the ignition burner at the top center of the gasifier. The high voltage discharge at the head of the igniter ignites and the ignition state is determined by the flame detector. After ignition is confirmed, the flow of oxygen and fuel gas is increased to increase the temperature in the furnace to create conditions for the input of coal powder, oxygen, water / organic waste liquid. Inert gas purge interfaces are set on the pipelines before oxygen and fuel gas enter the burner, which are used for purge before start-up and after shutdown, and for sealing during switching or operation failure to prevent "flashback" of high-temperature synthesis gas.

[0053] Pulverized coal and oxygen are fed into the gasifier one by one or simultaneously through three process burners evenly arranged around the ignition burner after successful ignition and the oxygen and fuel gas flow rates meet the specified requirements. Nitrogen purge interfaces are set on the pipelines before oxygen and fuel gas enter the burners for purge before start-up and after shutdown, and for sealing in case of operating failures to prevent "flashback" of high-temperature syngas.

[0054] After the pulverized coal and oxygen of the corresponding process burners are added and the operation is stable, water / organic waste liquid can be added. Water can be directly fed through the boiler water circulation pump. When feeding organic waste liquid, the conveying system needs to be started. The water / organic liquid channel is switched from inert gas to water / organic waste liquid, and the flow and proportion of oxygen, pulverized coal and water / organic waste liquid are adjusted to achieve good gasification efficiency in the furnace.

[0055] After the process burner is fed, the ignition burner can reduce the flow and heat load of oxygen and fuel gas and continue to be used as a permanent lamp, or inert gas can be introduced into the oxygen and fuel gas channels for positive pressure sealing protection.

[0056] The water / organic waste liquid feed of the process burner can be switched, the flow rate or ratio adjusted during operation, and the water / organic waste liquid can be withdrawn, or only inert gas can be introduced for positive pressure sealing protection. For example, during operation, when the organic waste liquid supply of the process burner is insufficient, part of the boiler water is sent to the liquid phase channel through valve switching to replace part of the organic waste liquid, forming a common feed of boiler water and organic waste liquid; when the supply of organic waste liquid stops, boiler water is used to completely replace the organic waste liquid and sent to the liquid phase channel to ensure the water content in the process burner feed, thereby ensuring the gasification effect; when the gasifier is in an unstable state or stopped, the feed in the liquid phase channel is switched to inert gas feed for positive pressure sealing protection.

[0057] Therefore, in the present invention, the flow ratio of water / organic waste liquid of the process burner can be controlled by split range, that is, the flow rates of water and organic waste liquid are adjusted to complement each other to meet the total water volume requirement.

[0058] Coal powder, oxygen, water / organic waste liquid undergo gasification reaction in the gasification chamber of the gasifier. The generated high-temperature synthesis gas carries molten ash into the cooling chamber through the slag outlet for cooling and ash separation, and is then sent to the post-system device as a product.

[0059] The invention is further described below with reference to the embodiments.

[0060] Implementation examples:

[0061] Coal chemical plants use coal as raw material to produce a variety of chemicals. The coal quality data is shown in Table 1. Some raw coal is pyrolyzed to produce tar, other oil products and coke powder, and some raw coal is gasified to produce synthesis gas for downstream synthesis of other chemicals. The wastewater discharged from tar wastewater has high COD and ammonia nitrogen content (water quality see Table 2), containing ammonia nitrogen, phenols, indoles, quinoline and other monocyclic or polycyclic aromatic compounds and heterocyclic organic matter containing nitrogen, sulfur and oxygen, which is one of the most difficult wastewaters to treat.

[0062] The gasification device in the plant uses multiple pulverized coal pressurized gasification equipment as above. Take a single gasification equipment with a coal input of 1,500 tons as an example. Figure 1 and 2As shown, a top-mounted 3+1 burner is used, namely, 1 ignition burner and 3 process burners. After ignition and start-up, the water / organic waste liquid channel of the process burner is fed with tar waste water, the gasification temperature is 1500℃, and the gasification pressure is 4.0MPaG. The coal input of each pulverized coal burner is 17t / h, oxygen is 9100Nm / h, and the organic waste liquid input is 8-10t / h. The production of synthesis gas (dry basis) is 90000Nm3 / h, the effective gas content is 92vol%, and the carbon conversion rate is 99%. The waste water discharged by gasification is 15t / h, and its main components are shown in Table 3, COD is less than 300mg / L, ammonia nitrogen is less than 250mg / L, and it does not contain organic compounds greater than 1 carbon. It can be treated by ordinary biochemical sewage treatment system and then reused or discharged in compliance with standards. When the coal pyrolysis gas purification device is shut down, water can be switched to serve as the auxiliary gasification agent with a flow rate of 8 to 9 t / h to ensure efficient operation of the gasifier.

[0063] Compared with the traditional pulverized coal gasification device with superheated steam, the oxygen heating system, steam pressure reduction and filtration system, and oxygen steam mixing system are eliminated, and the corresponding oxygen pipeline material is reduced from nickel-based alloy to stainless steel. A single system can save investment of 500,000 yuan and reduce steam use by 12t / h. During operation, the above-mentioned gasification system can treat 8-10t / h of organic waste liquid per set. Without considering the benefits of gasifying organic matter in wastewater to produce synthesis gas, compared with traditional organic waste liquid treatment methods, it can save investment in wastewater treatment equipment of 7 million yuan and save operating costs of wastewater treatment of 600,000 yuan / year (based on 8,000 hours of annual operation).

[0064] Table 1: Raw coal data table

[0065]

[0066]

[0067] Table 2: Tar wastewater quality table

[0068] project CODcr Ammonia nitrogen phenol SS PH unit mg / L mg / L mg / L mg / L Numeric 6900～7700 2500～2600 900～1100 <300 8～9

[0069] Table 3: Gasification wastewater quality table

[0070] project CODcr Ammonia nitrogen phenol SS PH unit mg / L mg / L mg / L mg / L Numeric <200 <100 0 <100 6～9

Claims

1. A coal gasification system for treating organic waste liquid, characterized in that: The gasification system comprises a gasifier, an organic waste liquid unit and a boiler water unit; wherein the gasifier comprises a gasification chamber separated by a water-cooled wall in a furnace body, a cooling chamber located below the gasification chamber and a slag lowering port connecting the gasification chamber and the cooling chamber, and a burner is provided on the top of the gasification chamber; the cooling chamber is used to cool down the gasification product from the slag lowering port; The burner portion comprises a burner seat fixed to the furnace body, an ignition burner arranged at the center of the burner seat, and a plurality of process burners uniformly arranged on the burner seat around the ignition burner; The ignition burner is provided with a fuel gas channel, an oxygen channel and a cooling water jacket from the inside to the outside, wherein an igniter and a flame detector are also provided in the fuel gas channel; The number of the process burners is 3 to 6; the process burners are arranged parallel to the axial direction of the gasifier; The process burner is used to feed gasification raw materials into the gasification chamber so as to carry out gasification reaction in the gasification chamber. The process burner is provided with an oxygen channel, a coal powder channel, a liquid phase channel and a cooling water jacket from the inside to the outside. The feed port of the liquid phase channel is connected to the boiler water unit, the organic waste liquid unit and the inert gas source through pipelines to receive boiler water from the boiler water unit, organic waste liquid from the organic waste liquid unit and inert gas; the boiler water unit is also provided with a pipeline for providing cooling water for the water-cooled wall and the burner cooling water jacket; The organic waste liquid unit comprises an organic waste liquid storage tank, a filter for filtering the organic waste liquid to be introduced into the organic waste liquid storage tank, a viscometer for measuring the viscosity of the organic waste liquid from the organic waste liquid storage tank, and a waste liquid delivery pump for delivering the organic waste liquid after the viscosity is measured into the liquid phase channel; The boiler unit comprises: A waste heat boiler, used to recover heat from boiler water of the water-cooled wall to produce steam as a by-product; A boiler water storage tank, used to receive boiler water after heat recovery from outside the boundary area and the waste heat boiler; A boiler water pump is used to deliver the boiler water in the boiler water storage tank into the liquid phase channel and as cooling water into the water-cooled wall and the burner cooling water jacket.

2. The coal gasification system according to claim 1, characterized in that: The burner heads of the oxygen channel and the pulverized coal channel are both provided with swirlers, so that oxygen and pulverized coal are ejected from the burner heads at certain tangential and axial speeds; the burner head of the liquid phase channel is provided with an ejector so that the liquid phase is broken up into atomized liquid and then ejected into the gasifier.

3. The gasification system according to claim 2, characterized in that: The cooling chamber is provided with a downcomer and a quenching ring arranged at the upper end of the downcomer, wherein the downcomer is used to introduce the gasification product from the lower slag outlet into the lower water bath of the quenching chamber for cooling and washing, and the quenching ring is used to spray quenching water to protect the downcomer.

4. The gasification system according to claim 3, characterized in that: The water-cooled wall is a spiral coil type or a tube-in-tube type water-cooled wall, and a water-cooled wall fireproof lining is laid on the fire side; the cooling water jackets of the ignition burner and the process burner are both provided with pipelines connected to the boiler water pump to receive cooling water.

5. A method for treating organic waste liquid using the coal gasification system according to any one of claims 1 to 4, wherein: The organic waste liquid is sprayed into the gasification chamber through the liquid phase channel for treatment; in, When ignition is started, oxygen and fuel gas are introduced through the ignition burner at the top center of the gasifier, and ignition is ignited by high voltage discharge at the igniter head. Then the ignition state is determined by the flame detector. After ignition is confirmed, the flow of oxygen and fuel gas is increased to increase the temperature in the furnace. After the ignition is successful and the oxygen and fuel gas flow rates meet the specified requirements, the pulverized coal and oxygen are gradually fed into the gasifier through the process burner; After the pulverized coal and oxygen of the corresponding process burner are put into operation and the operation is stable, the liquid phase channel is switched from inert gas to organic waste liquid, and then the flow rate and ratio of oxygen, pulverized coal and organic waste liquid of the process burner are adjusted to achieve good gasification efficiency in the furnace; After the process burner is charged, the flow rate and heat load of oxygen and fuel gas of the ignition burner are reduced to continue to be used as a permanent lamp, or inert gas is introduced into the oxygen and fuel gas channels of the ignition burner for positive pressure sealing protection; Wherein, when the organic waste liquid feed of the process burner is insufficient, part of the boiler water is fed into the liquid phase channel through valve switching to replace part of the organic waste liquid, thereby forming a common feed of boiler water and organic waste liquid; When the supply of organic waste liquid stops, boiler water is used to completely replace the organic waste liquid and sent into the liquid phase channel to ensure the water content in the feed of the process burner; When the gasifier is in an unstable state or stopped, the feed in the liquid phase channel is switched to inert gas feed for positive pressure sealing protection.

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