A system for treating coal gasification wastewater containing sulfur and high ammonia nitrogen

Abstract

A kind of coal gasification sulfur-containing high ammonia nitrogen wastewater treatment system, system one includes: wastewater storage tank, microchannel oxidation reactor, alkali mixed reaction kettle, filter press, ammonia water collection tank;System two includes: wastewater storage tank, microchannel oxidation reactor, alkali mixed reaction kettle, heat exchanger, stripping tower, ammonia water collection tank.The utility model discloses system simple structure, can effectively treat the complex wastewater system of high ammonia nitrogen, high COD, high carbonate and small amount of sulfide generated in the process of coal gasification, and convert the pollutants in wastewater into recyclable byproduct, realize the complete zero discharge of wastewater, process flow is simple, convenient operation, with good impact load capacity, low in cost, suitable for industrial production.

Description

Technical Field

[0001] This utility model relates to a treatment system for ammonia nitrogen wastewater, specifically a treatment system for sulfur-containing high ammonia nitrogen wastewater from coal gasification. Background Technology

[0002] Coal chemical engineering is a technological system that uses coal as raw material and transforms it into gaseous fuels, liquid fuels, and chemicals through chemical processing. Among them, coal gasification technology is the core process, which converts coal into syngas (mainly composed of CO and H2) under high temperature and high pressure conditions. Its complete process includes: raw material processing, gasification reaction, purification and refining (covering CO sulfur-resistant conversion and low-temperature methanol washing, etc.), and synthesis and utilization.

[0003] High-ammonia-nitrogen wastewater from coal gasification is typically represented by the condensate from the shift stripping system in a coal chemical plant. This stripping system is used for centralized treatment of shift condensate from the CO sulfur-resistant shift unit and process condensate from the low-temperature methanol washing unit. The incoming liquid contains dissolved CO2, H2S, NH3, methanol, and trace amounts of HCN and Cl. - Impurities such as CO2, H2S, and NH3 are efficiently separated after stripping, and the purified condensate meets reuse or discharge standards. The separated gas phase, after condensation and redissolved in water, forms a condensate containing high levels of ammonia nitrogen, high COD, high carbonate, and a small amount of sulfides. Industry regulations prohibit ammonia-containing wastewater from entering coal mill units to produce coal-water slurry, and also prohibit flares from being used as industrial devices to burn ammonia-containing gases. The aforementioned stripping gas phase condensate is a typical form of sulfur-containing, high-ammonia-nitrogen wastewater from coal gasification, and direct discharge is strictly prohibited; further treatment is required.

[0004] Currently, the treatment of coal chemical conversion condensate generally employs a combination of physical and chemical methods. A typical process involves adding reagents in conjunction with a stripping process to remove carbon dioxide and ammonia nitrogen, thereby recovering ammonia and sulfur; simultaneously, volatile organic compounds (VOCs) are introduced into a flare for treatment; the treated effluent that meets the standards can be recycled or fed into subsequent biochemical systems. However, this process has the following technical defects: During the condensation process, the carbon dioxide, ammonia, and water vapor in the mixed gas discharged from the top of the stripping tower easily recombine to form ammonium carbonate crystals, which accumulate at the bottom of the condenser. At the same time, the small amount of sulfides in the mixed gas will gradually corrode the equipment, which will not only lead to a decrease in separation efficiency, but also significantly shorten the service life of the condenser. If the mixed gas that has not been condensed is directly discharged, it will inevitably cause serious air pollution. After the mixed gas is condensed, the temperature is still as high as 50-80°C, with high ammonia nitrogen, high water vapor content and trace sulfur ions. These characteristics of high temperature, high water vapor and sulfur content can easily cause the flare to go out. The organic matter contained in the mixed gas will partially dissolve in the condensate during the condensation process, interfering with the efficient recovery of ammonia and sulfur.

[0005] CN113526716A discloses a process for reducing ammonia nitrogen in high-ammonia-nitrogen wastewater, which uses catalytic wet oxidation and stripping to remove ammonia nitrogen from acesulfame potassium production wastewater. While this reduces COD and ammonia nitrogen in the wastewater, it does not recover the stripped ammonia nitrogen and is unsuitable for wastewater containing high levels of carbonate. During the wet catalytic oxidation process, carbonate and ammonia in the wastewater can form ammonium carbonate and crystallize, posing a risk of clogging equipment and pipelines.

[0006] In summary, there is an urgent need to find a simple system that can effectively treat complex wastewater containing high ammonia nitrogen, high COD, high carbonate, and a small amount of sulfides generated during coal gasification, and convert the pollutants in the wastewater into recyclable by-products, achieving complete zero discharge of wastewater. The system should have a simple process flow, be easy to operate, have good resistance to shock loads, be low in cost, and be suitable for the treatment of sulfur-containing, high ammonia nitrogen wastewater from coal gasification in industrial production. Utility Model Content

[0007] The technical problem to be solved by this utility model is to overcome the above-mentioned defects of the existing technology and provide a simple structure that can effectively treat complex wastewater containing high ammonia nitrogen, high COD, high carbonate and a small amount of sulfides generated in the coal gasification process, and convert the pollutants in the wastewater into recyclable by-products, achieving complete zero discharge of wastewater. The process is simple, easy to operate, has good resistance to shock loads, low cost, and is suitable for the treatment of sulfur-containing high ammonia nitrogen wastewater from coal gasification in industrial production.

[0008] The technical solution adopted by this utility model to solve its technical problem is as follows: a treatment system for sulfur-containing and high ammonia nitrogen wastewater from coal gasification. System 1 includes: wastewater storage tank, microchannel oxidation reactor, alkali mixing reactor, filter press, and ammonia collection tank; System 2 includes: wastewater storage tank, microchannel oxidation reactor, alkali mixing reactor, heat exchanger, stripping tower, and ammonia collection tank; In systems one and two, the wastewater storage tank is provided with a wastewater inlet and a return inlet on one side, and a wastewater outlet on the other side. The wastewater outlet is connected to the wastewater inlet on one side of the microchannel oxidation reactor via a pump, and the oxidation desulfurization wastewater outlet on the other side is connected to the oxidation desulfurization wastewater inlet at the top of the alkali mixing reactor. In System 1, the mixing outlet at the bottom of the alkali mixing reactor is connected to the feed inlet of the filter press via a pump; the liquid outlet of the filter press is connected to the ammonia inlet of the ammonia collection tank; and the filter press is also equipped with a discharge outlet. In System 2, the mixing outlet at the bottom of the alkali mixing reactor is connected to the shell-side inlet of one end of the heat exchanger via a pump, and the shell-side outlet at the other end of the heat exchanger is connected to the alkali treatment wastewater inlet at the middle and upper parts of the stripping tower; the lower part of the stripping tower is also provided with a carrier gas inlet, and the bottom liquid outlet of the stripping tower is provided at the bottom and connected to the return inlet of the wastewater storage tank; the carrier gas inlet is connected to a gas distributor, and the top of the stripping tower is provided with a tail gas discharge outlet; a steam tube inlet is provided near the shell-side outlet of the heat exchanger, and a condensate tube outlet is also provided on the heat exchanger.

[0009] The working process of the coal gasification sulfur-containing high ammonia nitrogen wastewater treatment system of this utility model is as follows: The coal gasification sulfur-containing high ammonia nitrogen wastewater in the wastewater storage tank is pumped from the wastewater outlet into the wastewater inlet of the microchannel oxidation reactor. At the same time, the oxidant is pumped in through the oxidant inlet of the microchannel oxidation reactor. After the circulating cooling water is turned on to control the temperature and carry out the oxidation and desulfurization reaction, the desulfurized wastewater is pumped into the alkali mixing reactor. Alkali is added at the alkali inlet and after alkali treatment, it is sent to the filter press for solid-liquid separation. The ammonia water is discharged through the outlet of the filter press and sent to the ammonia water collection tank for collection or returned to the wastewater storage tank. The mixed sediment is discharged from the outlet of the filter press.

[0010] The working process of the second treatment system for coal gasification sulfur-containing high ammonia nitrogen wastewater of this utility model is as follows: The coal gasification sulfur-containing high ammonia nitrogen wastewater in the wastewater storage tank is pumped from the wastewater outlet into the wastewater inlet of the microchannel oxidation reactor. At the same time, the oxidant is pumped in through the oxidant inlet of the microchannel oxidation reactor. After the circulating cooling water is turned on to control the temperature and carry out the oxidation and desulfurization reaction, the desulfurized wastewater is pumped into the alkali mixing reactor. Alkali solution is added at the alkali inlet for alkali treatment. After alkali treatment, the alkali-treated wastewater is sent to the shell-side inlet of one end of the heat exchanger. After being heated by steam heat exchange, it is discharged from the shell-side outlet of the other end of the heat exchanger and sent to the stripping tower for spraying. Carrier gas is introduced into the carrier gas inlet at the bottom of the stripping tower to strip the alkali-treated wastewater. The resulting bottom liquid of the stripping tower is returned to the wastewater storage tank or transported to the outside for the preparation of coal-water slurry.

[0011] Preferably, in systems one and two, the Reynolds number of the microchannel oxidation reactor is 100–2000 (more preferably 1000–2000). The use of a microchannel oxidation reactor can reduce the amount of oxidant used, accelerate the reaction rate, and lower reaction conditions, thus saving costs. When the Reynolds number is too low, laminar flow dominates, resulting in a long diffusion distance, which reduces the diffusion rate, prolongs the reaction time, and decreases the reaction rate. When the Reynolds number is too high, the pressure drop is too large, and turbulent pulsation easily accelerates the decomposition of the oxidant, increasing reagent costs.

[0012] Preferably, in systems one and two, the type of microchannel includes passive microchannels, etc.

[0013] Preferably, in systems one and two, the passive type includes T-shaped, Y-shaped, umbrella-shaped, or heart-shaped, etc. More preferably, it is heart-shaped. Microchannel oxidation reactors have the advantages of large specific surface area, short diffusion distance, and high mass transfer efficiency. The heart-shaped structure can even generate Dean's vortex at bends, as well as local turbulence (Re peak value can reach 5000) to improve mixing.

[0014] Preferably, in systems one and two, the microchannel oxidation reactor is made of one or more of the following materials: stainless steel, duplex stainless steel, Hastelloy, glass, ceramics, or engineering plastics. The stainless steel includes one or more of SS316, SS316L, or SS304. The duplex stainless steel includes 2205 and / or 2507 duplex stainless steel. The engineering plastics include PTFE and / or PEEK.

[0015] Preferably, systems one and two also include an oxidant storage tank and an alkali storage tank. An alkali storage tank is provided when the alkali is added in liquid or solution form.

[0016] Preferably, in systems one and two, the outlet of the oxidant storage tank is connected to the oxidant inlet of the microchannel oxidation reactor via a pump.

[0017] Preferably, in systems one and two, the oxidant storage tank is also provided with a feed inlet.

[0018] Preferably, in systems one and two, the outlet of the alkali storage tank is connected to the alkali inlet on the alkali mixing reactor via a pump.

[0019] Preferably, in systems one and two, the alkali storage tank is also provided with a feed inlet.

[0020] Preferably, in systems one and two, the microchannel oxidation reactor is further provided with an oxidant inlet.

[0021] Preferably, in systems one and two, the cooling channel on the outer layer of the microchannel oxidation reactor is further provided with a cooling water inlet and a cooling water outlet.

[0022] Preferably, in systems one and two, an oxidation-reduction potential detector is provided on the microchannel oxidation reactor and / or outside the outlet of its desulfurization wastewater.

[0023] Preferably, in systems one and two, the upper part of the alkali mixing reactor is also provided with an alkali inlet.

[0024] Preferably, in systems one and two, the ammonia collection tank is also provided with an ammonia outlet.

[0025] Preferably, in System 2, the stripping tower includes a Mem microfilm stripping tower, etc.

[0026] Preferably, in System 2, the gas distributor includes Nanofiltrate developed by Hunan Zhongtianyuan Environmental Engineering Co., Ltd. TM Membrane gas distributor. Utilizing microporous dispersion technology, it can form micro-nano bubbles, resulting in good gas distribution uniformity, high mass transfer efficiency, and good anti-clogging ability, which is more conducive to ammonia stripping.

[0027] Preferably, in system two, an adsorption tower and an absorption tower are connected in series after the stripping tower.

[0028] Preferably, in system two, the exhaust port of the stripping tower is connected to the air inlet at the bottom of the adsorption tower.

[0029] Preferably, in System 2, the top of the adsorption tower is provided with an adsorption tower tail gas discharge port, and the bottom of the adsorption tower is provided with an adsorption tower bottom liquid outlet connected to the return water inlet of the wastewater storage tank.

[0030] Preferably, in System 2, the adsorption tower includes a packed tower, etc.

[0031] Preferably, the packing material in the packed tower includes activated carbon and / or molecular sieves. The packing material can selectively adsorb and remove low-boiling-point organic matter and ammonia from the mixed gas, preventing organic matter from entering the absorption tower and being absorbed by the absorbent, thus affecting the quality of the dilute ammonia solution. Activated carbon is more preferably used as the packing material.

[0032] Preferably, in System 2, the adsorption tower is made of materials including stainless steel. The stainless steel includes SS304, etc.

[0033] Preferably, in system two, the exhaust port of the adsorption tower is connected to the air inlet at the bottom of the absorption tower.

[0034] Preferably, in System 2, the top of the absorption tower is provided with an absorption tower tail gas emission port.

[0035] Preferably, in System 2, the bottom of the absorption tower is provided with a circulating absorbent outlet, which is connected to the circulating absorbent inlet at the top of the absorption tower via a pump or to the ammonia inlet of the ammonia collection tank.

[0036] Preferably, in system two, the lower part of the absorption tower is also provided with a water inlet.

[0037] Preferably, in system two, the absorption tower includes a spray tower or a packed tower, etc. A spray tower is more preferably used as the absorption tower.

[0038] Preferably, in System 2, the absorption tower is a dual-tower series configuration. The first-stage absorption tower removes most of the ammonia, and the remaining gas enters the second-stage absorption tower for further treatment to ensure that the ammonia is fully absorbed.

[0039] Preferably, in system two, the absorption tower is filled with packing material. The packing material can enhance the gas-liquid contact surface area.

[0040] Preferably, the packing includes one or more of the following: corrugated plates, Pall rings, stepped rings, or rectangular saddle packing.

[0041] Preferably, in System 2, the absorber and packing material includes stainless steel, etc. The stainless steel includes SS304, etc.

[0042] The working process when an adsorption tower and an absorption tower are installed is as follows: the tail gas from the stripping tower is sent to the adsorption tower for adsorption. The resulting bottom liquid from the adsorption tower is pumped back to the wastewater storage tank through the bottom liquid outlet of the adsorption tower. The tail gas from the adsorption tower is sent to the absorption tower for absorption. The water inlet at the bottom of the absorption tower replenishes the absorbent. The circulating absorbent outlet is pumped to the circulating absorbent inlet at the top of the absorption tower for spraying, and countercurrent absorption is performed. When the circulating absorbent is enriched with ammonia and becomes dilute ammonia water, it is sent to the ammonia water collection tank through the circulating absorbent outlet. When multiple absorption towers are connected in series, this process is repeated, and the tail gas from the absorption tower is sent to the next stage absorption tower for further absorption.

[0043] The beneficial effects of this utility model's coal gasification wastewater treatment system for sulfur-containing and high-ammonia-nitrogen wastewater are as follows: (1) The treatment system for sulfur-containing and high ammonia nitrogen wastewater from coal gasification of this utility model adopts a microchannel oxidation reactor, which has high mass and heat transfer efficiency, high oxidant utilization rate, and precise reaction temperature control; Mem microfilm stripping tower and Nanofiltrate are selected. TM Membrane gas distributors can increase stripping efficiency and reduce carrier gas costs. The bottom liquid of the stripping tower can be reused or used for coal-water slurry preparation. An adsorption tower is set up before the absorption tower to adsorb and remove low-boiling-point organic matter in the stripped mixed gas, preventing an increase in COD in the dilute absorbent. (2) The treatment system for sulfur-containing high ammonia nitrogen wastewater from coal gasification has a simple structure. In view of the water quality characteristics of high ammonia nitrogen, high COD, high carbonate and sulfide in coal gasification high ammonia nitrogen wastewater, the organic coupling of multiple devices can effectively remove sulfides and ammonia nitrogen from the wastewater. The treatment efficiency meets the requirements. Ammonia gas is recovered to produce dilute ammonia water by-product. The bottom liquid of the stripping tower is used for resource utilization. The resource utilization path is clear, which effectively reduces the cost and achieves complete zero discharge of wastewater. The process is simple and easy to operate. It has good resistance to shock loads, low cost and is suitable for industrial production. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the treatment system for sulfur-containing and high-ammonia-nitrogen wastewater from coal gasification of this utility model; Figure 2 This is a schematic diagram of the structure of Embodiment 2 of the treatment system for sulfur-containing and high ammonia nitrogen wastewater from coal gasification according to this utility model. Detailed Implementation

[0045] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0046] The Nanofiltrate used in this embodiment of the utility model TM The membrane gasifier was purchased from Hunan Zhongtianyuan Environmental Engineering Co., Ltd.

[0047] Example 1 of a treatment system for sulfur-containing, high-ammonia-nitrogen wastewater from coal gasification The treatment system for sulfur-containing and high ammonia nitrogen wastewater from coal gasification includes: wastewater storage tank 1, microchannel oxidation reactor 2, alkali mixing reactor 3, filter press 4, ammonia water collection tank 9, oxidant storage tank 10, and alkali solution storage tank 11. The wastewater storage tank 1 has a wastewater inlet 1-1 and a return inlet 1-2 on one side, and a wastewater outlet 1-3 on the other side. The wastewater outlet 1-3 is connected to the wastewater inlet 2-1 on one side of the microchannel oxidation reactor 2 via a pump 12, and the oxidation desulfurization wastewater outlet 2-3 on the other side is connected to the oxidation desulfurization wastewater inlet 3-1 at the top of the alkali mixing reactor 3. The mixing outlet 3-3 at the bottom of the alkali mixing reactor 3 is connected to the feed inlet 4-1 of the filter press via a pump 12. The liquid outlet 4-2 of the filter press is connected to the ammonia inlet 9-1 of the ammonia collection tank 9. The filter press is also equipped with a discharge outlet 4-3. The microchannel oxidation reactor 2 is a passive heart-shaped microchannel oxidation reactor with a Reynolds number of 1600, and the material is 316L. The outlet 10-2 of the oxidant storage tank 10 is connected to the oxidant inlet 2-2 of the microchannel oxidation reactor 2 via a pump 12; the oxidant storage tank 10 is also provided with an inlet 10-1; the outlet 11-2 of the alkali storage tank 11 is connected to the alkali inlet 3-2 of the alkali mixing reactor via a pump 12; the alkali storage tank 11 is also provided with an inlet 11-1; The microchannel oxidation reactor 2 is also equipped with an oxidant inlet 2-2; the cooling channel on the outer layer of the microchannel oxidation reactor 2 is also equipped with a cooling water inlet 2-4 and a cooling water outlet 2-5; an oxidation-reduction potential detector 2-6 is provided outside the oxidation and desulfurization wastewater outlet 2-3 of the microchannel oxidation reactor 2; an alkali inlet 3-2 is also provided on the upper part of the alkali mixing reactor; and an ammonia water outlet 9-2 is also provided on the ammonia water collection tank 9.

[0048] The working process of this utility model's coal gasification sulfur-containing high ammonia nitrogen wastewater treatment system is as follows: The coal gasification sulfur-containing high ammonia nitrogen wastewater in the wastewater storage tank 1 is pumped from the wastewater outlet 1-3 into the wastewater inlet 2-1 of the microchannel oxidation reactor 2 through pump 12. At the same time, the oxidant is pumped in through the oxidant inlet 2-2 of the microchannel oxidation reactor 2. After the circulating cooling water is turned on to control the temperature and carry out the oxidation and desulfurization reaction, the desulfurized wastewater is pumped into the alkali mixing reactor 3. Alkali is added at the alkali inlet 3-2 for alkali treatment. After alkali treatment, it is sent to the filter press 4 for solid-liquid separation. The ammonia water is discharged through the liquid outlet 4-2 of the filter press 4 and sent to the ammonia water collection tank 9 for collection or returned to the wastewater storage tank 1. The mixed sediment is discharged through the discharge outlet 4-3 of the filter press 4.

[0049] Example 2 of a treatment system for sulfur-containing, high-ammonia-nitrogen wastewater from coal gasification The treatment system for sulfur-containing and high ammonia nitrogen wastewater from coal gasification includes: wastewater storage tank 1, microchannel oxidation reactor 2, alkali mixing reactor 3, heat exchanger 5, stripping tower 6, ammonia water collection tank 9, oxidant storage tank 10, alkali storage tank 11, adsorption tower 7, and absorption tower 8. The wastewater storage tank 1 has a wastewater inlet 1-1 and a reflux inlet 1-2 on one side, and a wastewater outlet 1-3 on the other side. The wastewater outlet 1-3 is connected to the wastewater inlet 2-1 on one side of the microchannel oxidation reactor 2 via a pump 12, and the oxidation desulfurization wastewater outlet 2-3 on the other side is connected to the oxidation desulfurization wastewater inlet 3-1 at the top of the alkali mixing reactor 3. The mixing outlet 3-3 at the bottom of the alkali mixing reactor 3 is connected to the shell-side inlet 5-1 at one end of the heat exchanger 5 via a pump 12, and the shell-side outlet 5-2 at the other end of the heat exchanger 5 is connected to the alkali treatment wastewater inlet 6-1 at the middle and upper part of the stripping tower 6. The stripping tower 6 also has a carrier gas inlet 6-2 at the bottom and a bottom liquid outlet 6-4 at the bottom, which is connected to the reflux inlet 1-2 of the wastewater storage tank 1. The carrier gas inlet 6-2 is connected to a Nanofiltrate. TM The membrane gas distributor 6-5 and the top of the stripping tower 6 are provided with a stripping tower tail gas discharge port 6-3; the stripping tower is a Mem micro membrane stripping tower; a steam tube inlet 5-3 is provided near the shell-side outlet 5-2 of the heat exchanger 5; the heat exchanger 5 is also provided with a condensate tube-side outlet 5-4. The microchannel oxidation reactor 2 is a passive heart-shaped microchannel oxidation reactor with a Reynolds number of 1600, and the material is 316L. The outlet 10-2 of the oxidant storage tank 10 is connected to the oxidant inlet 2-2 of the microchannel oxidation reactor 2 via a pump 12; the oxidant storage tank 10 is also provided with an inlet 10-1; the outlet 11-2 of the alkali storage tank 11 is connected to the alkali inlet 3-2 of the alkali mixing reactor 3 via a pump 12; the alkali storage tank 11 is also provided with an inlet 11-1; The microchannel oxidation reactor 2 is also equipped with an oxidant inlet 2-2; the cooling channel on the outer layer of the microchannel oxidation reactor 2 is also equipped with a cooling water inlet 2-4 and a cooling water outlet 2-5; an oxidation-reduction potential detector 2-6 is installed outside the oxidation and desulfurization wastewater outlet 2-3 of the microchannel oxidation reactor 2; an alkali inlet 3-2 is also provided on the upper part of the alkali mixing reactor 3; and an ammonia water outlet 9-2 is also provided on the ammonia water collection tank 9. The stripping tower 6 has a tail gas discharge port 6-3 connected to the air inlet 7-1 at the bottom of the adsorption tower 7; the adsorption tower 7 has a tail gas discharge port 7-2 at the top and a bottom liquid outlet 7-3 at the bottom, which is connected to the return inlet 1-2 of the wastewater storage tank 1; the adsorption tower 7 is a packed tower made of SS304 and filled with activated carbon. The exhaust port 7-2 of the adsorption tower 7 is connected to the air inlet 8-1 at the bottom of the absorption tower 8; the top of the absorption tower 8 is provided with the exhaust port 8-2; the bottom of the absorption tower 8 is provided with the circulating absorbent outlet 8-3, which is connected to the circulating absorbent inlet 8-4 at the top of the absorption tower 8 via pump 12 or to the ammonia inlet 9-1 of the ammonia collection tank 9; the bottom of the absorption tower 8 is also provided with the water replenishment port 8-5; the absorption tower 8 is a spray tower, with two towers connected in series, and the material is SS304; the absorption tower 8 is filled with corrugated plate packing 8-6, which is made of SS304.

[0050] The working process of this utility model's coal gasification sulfur-containing high ammonia nitrogen wastewater treatment system is as follows: The coal gasification sulfur-containing high ammonia nitrogen wastewater in the wastewater storage tank 1 is pumped from the wastewater outlet 1-3 into the wastewater inlet 2-1 of the microchannel oxidation reactor 2 via pump 12. Simultaneously, the oxidant is pumped in through the oxidant inlet 2-2 of the microchannel oxidation reactor 2. After the circulating cooling water is turned on to control the temperature and the oxidation and desulfurization reaction is carried out, the desulfurized wastewater is pumped into the alkali mixing reactor 3. An alkali solution is added at the alkali inlet 3-2 for alkali treatment. The alkali-treated wastewater is then sent to the shell-side inlet 5-1 at one end of the heat exchanger 5. After being heated by steam heat exchange, it is discharged from the shell-side outlet 5-2 at the other end of the heat exchanger 5 and sent to the stripping tower 6 for spraying. Air is introduced into the carrier gas inlet 6-2 at the bottom of the stripping tower 6. Carrier gas is used to strip alkaline wastewater. The resulting bottom liquid from the stripping tower is returned to wastewater storage tank 1 through the bottom liquid outlet 6-4 or transported externally for the preparation of coal-water slurry. The tail gas from the stripping tower is sent to adsorption tower 7 for adsorption. The resulting bottom liquid from the adsorption tower is returned to wastewater storage tank 1 through the bottom liquid outlet 7-3 via pump 12. The tail gas from the adsorption tower is sent to absorption tower 8 for absorption. The water supply outlet 8-5 at the bottom of absorption tower 8 replenishes the absorbent. The circulating absorbent outlet 8-3 is pumped by pump 12 to the circulating absorbent inlet 8-4 at the top of absorption tower 8 for spraying and countercurrent absorption. When the circulating absorbent is enriched with ammonia to dilute ammonia water, it is sent to ammonia water collection tank 9 through the circulating absorbent outlet 8-3 for collection. This process is repeated until the tail gas from absorption tower 8 is sent to the next stage absorption tower 8 for further absorption.

Claims

1. A treatment system for sulfur-containing, high-ammonia-nitrogen wastewater from coal gasification, characterized in that: System 1 includes: wastewater storage tank, microchannel oxidation reactor, alkali mixing reactor, filter press, and ammonia collection tank; System 2 includes: wastewater storage tank, microchannel oxidation reactor, alkali mixing reactor, heat exchanger, stripping tower, and ammonia collection tank; In systems one and two, the wastewater storage tank is provided with a wastewater inlet and a return inlet on one side, and a wastewater outlet on the other side. The wastewater outlet is connected to the wastewater inlet on one side of the microchannel oxidation reactor via a pump, and the oxidation desulfurization wastewater outlet on the other side is connected to the oxidation desulfurization wastewater inlet at the top of the alkali mixing reactor. In System 1, the mixing outlet at the bottom of the alkali mixing reactor is connected to the feed inlet of the filter press via a pump; the liquid outlet of the filter press is connected to the ammonia inlet of the ammonia collection tank; and the filter press is also equipped with a discharge outlet. In System 2, the mixing outlet at the bottom of the alkali mixing reactor is connected to the shell-side inlet of one end of the heat exchanger via a pump, and the shell-side outlet at the other end of the heat exchanger is connected to the alkali treatment wastewater inlet at the middle and upper parts of the stripping tower; the lower part of the stripping tower is also provided with a carrier gas inlet, and the bottom liquid outlet of the stripping tower is provided at the bottom and connected to the return inlet of the wastewater storage tank; the carrier gas inlet is connected to a gas distributor, and the top of the stripping tower is provided with a tail gas discharge outlet; a steam tube inlet is provided near the shell-side outlet of the heat exchanger, and a condensate tube outlet is also provided on the heat exchanger.

2. The treatment system for sulfur-containing, high-ammonia-nitrogen wastewater from coal gasification according to claim 1, characterized in that: In Systems 1 and 2, the Reynolds number of the microchannel oxidation reactor is 100 to 2000; the type of microchannel includes passive type; the passive type includes T-type, Y-type, umbrella-type, or heart-type; the material of the microchannel oxidation reactor includes one of stainless steel, duplex steel, Hastelloy, glass, ceramic, or engineering plastics. In systems one and two, an oxidant storage tank and an alkali storage tank are also provided; the outlet of the oxidant storage tank is connected to the oxidant inlet of the microchannel oxidation reactor via a pump; the oxidant storage tank is also provided with a feed inlet; the outlet of the alkali storage tank is connected to the alkali inlet of the alkali mixing reactor via a pump; the alkali storage tank is also provided with a feed inlet. In systems one and two, the microchannel oxidation reactor is also equipped with an oxidant inlet; the cooling channel on the outer layer of the microchannel oxidation reactor is also equipped with a cooling water inlet and a cooling water outlet; the microchannel oxidation reactor and / or its desulfurization wastewater outlet are equipped with an oxidation-reduction potential detector; the upper part of the alkali mixing reactor is also equipped with an alkali inlet; and the ammonia water collection tank is also equipped with an ammonia water outlet. In System 2, the stripping tower includes a Mem microfilm stripping tower.

3. The treatment system for sulfur-containing, high-ammonia-nitrogen wastewater from coal gasification according to claim 1 or 2, characterized in that: In System 2, an adsorption tower and an absorption tower are connected in series after the stripping tower; The stripping tower's exhaust gas outlet is connected to the air inlet at the bottom of the adsorption tower; the adsorption tower has an adsorption tower exhaust gas outlet at the top and an adsorption tower bottom liquid outlet at the bottom, which is connected to the return water inlet of the wastewater storage tank; the adsorption tower includes a packed tower; the packing material in the packed tower includes activated carbon and / or molecular sieves; the material of the adsorption tower includes stainless steel. The exhaust port of the adsorption tower is connected to the air inlet at the bottom of the absorption tower; the top of the absorption tower is provided with an exhaust port; the bottom of the absorption tower is provided with a circulating absorbent outlet connected to the circulating absorbent inlet at the top of the absorption tower via a pump or connected to the ammonia inlet of the ammonia collection tank; a water replenishment port is also provided at the bottom of the absorption tower; the absorption tower includes a spray tower or a packed tower; the absorption tower adopts a double-tower series configuration; the absorption tower is filled with packing material; the packing material includes one or more of corrugated plates, Pall rings, stepped rings or rectangular saddle packing; the material of the absorption tower and the packing material includes stainless steel.

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