Method for up-to-standard treatment of waste alkali liquor of coal-to-olefin device

Abstract

The invention provides a coal-to-olefin device waste lye up-to-standard treatment method which comprises the following steps: (1) removal of butter in waste lye: the butter in the waste lye is removed by a butter remover with a special structural design; (2) butter-removing waste alkali liquor treatment: performing ozone oxidation and biochemical pretreatment on the butter-removing waste alkali liquor, then performing filtration, post-ozone oxidation and deep treatment by a biological aerated filter, and discharging the butter-removing waste alkali liquor after the butter-removing waste alkali liquor reaches the standard; and (3) innocent treatment of the butter and regeneration and recycling of the accompanying sand: mixing the butter and the accompanying sand in proportion, carrying out incineration treatment, removing the butter, and regenerating and recycling the accompanying sand at the same time. The method can effectively treat the butter in the waste lye, solves the problem of butter blockage in the waste lye treatment process, and realizes up-to-standard discharge of the high-COD and high-salt waste lye.

Description

Technical Field

[0001] This invention relates to a method for treating waste alkaline solution from a coal-to-olefins plant to meet emission standards, belonging to the field of environmental engineering technology. Background Technology

[0002] Ethylene, propylene, and other low-carbon olefins are important organic chemical raw materials. Traditionally, ethylene and propylene have primarily been sourced from hydrocarbon steam cracking, with naphtha as the main feedstock. my country, a country with abundant coal reserves but limited oil resources, has the potential to vigorously develop its coal chemical industry. Over the past 20 years, with domestic technological breakthroughs, coal-to-olefins has gradually become an important component of China's olefin production route. This is of great significance for reducing dependence on imported petroleum feedstocks, ensuring national energy security, and meeting the growing demand for downstream chemicals.

[0003] The olefin separation unit of a coal-to-olefins plant uses sodium hydroxide solution for washing to remove carbon dioxide gas from the reaction gases. However, this alkaline washing process generates a large amount of high-COD, high-salt waste alkaline solution. Furthermore, unsaturated hydrocarbons in the waste alkaline solution undergo free radical reactions under trace oxygen conditions, forming cross-linked polymers; aldehydes, ketones, and other oxygen-containing compounds undergo aldol condensation reactions under alkaline conditions, forming high-molecular-weight polymers, commonly known as "butter." The waste alkaline solution contains large amounts of inorganic salts such as sodium hydroxide and sodium carbonate, making it strongly alkaline. The butter in the waste alkaline solution has poor fluidity and easily clogs pipes; the organic pollutants are complex in composition, have poor biodegradability, and cannot be accepted by wastewater treatment systems.

[0004] The most common method for treating waste alkaline liquor from coal-to-olefins plants, both domestically and internationally, is incineration. This involves directly incinerating the waste alkaline liquor at approximately 1100℃. The incineration process is as follows: In the incinerator, fuel is completely burned in the burner chamber, releasing heat and forming high-temperature flue gas that flows downwards into the furnace. The waste alkaline liquor, after atomization, enters from the top of the furnace and comes into contact with the high-temperature flue gas. Through this contact, the organic matter in the waste alkaline liquor is oxidized and decomposed, transforming into inorganic salts, carbon dioxide, and water. However, waste alkaline liquor containing grease enters the furnace through nozzles, and the grease adhesion can cause nozzle blockage. Furthermore, the sodium hydroxide and sodium carbonate in the waste alkaline liquor, when burned at high temperatures, form molten ash. This molten material adheres to the furnace walls and tubes, combining with fly ash in the flue gas. This ash then cools and hardens in the slightly cooler waste heat recovery boiler, quench tower, and flue, forming hard coke and ash deposits, causing blockages and leading to frequent shutdowns for maintenance, preventing normal and stable operation of the incinerator. In addition, due to direct incineration, the volume of waste alkali liquid is large, resulting in high investment in incinerators, high operating costs, and a large amount of hazardous waste generated.

[0005] Some coal-to-olefins enterprises mix waste alkaline solutions with coal and then send them to boilers for incineration, or use the waste alkaline solutions as coal grinding water. This is actually a pollution transfer of waste.

[0006] The "Action Plan for Comprehensive Management of Solid Waste," issued on December 27, 2025, proposes to "deepen special rectification campaigns, strictly implement closed-loop management, and build a comprehensive solid waste management system that includes source reduction, process control, end-of-pipe utilization, and harmless management throughout the entire chain. By 2030, significant results will be achieved in the special rectification of solid waste in key areas." Therefore, effectively addressing the issue of treating coal-to-olefins waste alkali liquor and reducing or eliminating solid waste generation during the treatment process has become an urgent problem for enterprises.

[0007] In view of the aforementioned problems in the treatment of waste alkaline liquid from coal-to-olefins plants, developing a method that can operate stably and continuously, generate no hazardous waste during the process, and treat waste alkaline liquid from coal-to-olefins plants in compliance with standards is of great significance to enterprises, especially those in coastal areas that have wastewater discharge requirements. Summary of the Invention

[0008] To address the problems in the prior art, the purpose of this invention is to provide a method for treating waste alkaline solution from a coal-to-olefins plant to meet standards. This method utilizes the principle of communicating vessels to perform fully automated hydraulic degreasing of waste alkaline solution containing butter, under suitable temperature ranges (energy saving, gravity separation capability, and minimizing organic matter dissolution) and appropriate surface hydraulic load conditions. Simultaneously, measures such as lining the butter discharge pipes with oleophobic materials, using higher heating temperatures, and lining the butter delivery pipes and butter bags with oleophobic materials are employed to improve the butter's fluidity and prevent blockage of equipment and pipes. The butter separated from the waste alkaline solution is mixed with accompanying sand in a specific ratio (the purpose of adding accompanying sand is to ensure uniform heating and complete pyrolysis of the butter during pyrolysis, preventing the formation of carbon black). High-temperature complete pyrolysis is then performed using a sand-frying method. The pyrolysis-regenerated accompanying sand is cooled, desalinated, dehydrated, and recycled. High-temperature dust removal is also applied to the incinerator flue gas to address the problem of harmless butter treatment in a reasonable and feasible manner. Finally, a combined chemical strong oxidation and biochemical process is used to treat the difficult-to-biochemical organic wastewater to meet discharge standards under high salinity conditions of 12000~18000 mg / L.

[0009] Using the method of this invention, the grease in coal-to-olefins waste alkaline solution can be effectively removed, enabling the waste alkaline solution to meet discharge standards. This method has the advantages of high processing efficiency, ease of operation, and ease of industrial application.

[0010] To achieve the above objectives, the present invention employs the following technical means:

[0011] The present invention provides a method for treating waste alkaline solution from a coal-to-olefins plant to meet emission standards, comprising the following steps performed sequentially:

[0012] (1) Removal of butter from waste alkali solution

[0013] Waste alkaline liquid from the coal-to-olefins unit is transported to a grease remover. The density difference between the grease and the waste alkaline liquid causes them to separate into layers. The upper part of the grease remover contains grease, and the lower part contains the grease-removed waste alkaline liquid. The separated grease flows by gravity to a grease bag for collection, while the grease-removed waste alkaline liquid is sent to a buffer tank through a drainage level regulator. The inner walls of the grease bag and the grease conveying pipeline are lined with an oleophobic material. At the same time, the grease remover, grease bag, and grease conveying pipeline are equipped with heat tracing.

[0014] (2) Treatment of waste alkali solution for removing butter

[0015] (2a) Pretreatment of waste alkaline solution

[0016] The waste alkaline solution obtained after step (1) is treated with 1 to 1.5 times the weight of the waste alkaline solution and diluted with cooling brine containing sand. The solution is mixed in a buffer tank, cooled, and then sent to an ozone oxidation reactor. Ozone is introduced to break down the chains of the organic matter in the waste alkaline solution and oxidize it with ozone, thereby improving the biodegradability of the waste alkaline solution. The effluent from the ozone oxidation reactor is neutralized with acidic substances and sent to a degassing tank for degassing. The cooling brine containing sand is the water used in step (3) for cooling and washing the sand from the incinerator. The sodium carbonate content is less than 1% and the COD is less than 10 mg / L.

[0017] The effluent from the degassing tank is mixed with the conditioning water and then enters the biochemical reactor. The total dissolved solids (TDS) of the mixed wastewater is controlled at 12,000~18,000 mg / L. At the same time, antagonistic nutrients are added in proportion, air is blown in, and biochemical treatment is carried out. Organic pollutants in the mixed wastewater are removed by aerobic microorganisms, and the treated effluent is discharged to buffer tank two.

[0018] (2b) Deep treatment of waste alkaline solution

[0019] The mixed wastewater treated in step (2a) is sent to a filter to remove particulate pollutants such as suspended solids (SS). The mixed wastewater then enters a post-ozone reactor where ozone is introduced to chemically oxidize the organic matter in the mixed wastewater that is difficult to biodegrade.

[0020] The effluent from the post-ozone reactor is degassed and sent to the aerated biological filter, where air is blown in to biochemically degrade the remaining organic matter in the mixed wastewater. The effluent is then sent to the monitoring pool and discharged in compliance with standards.

[0021] The waste gas generated during ozone oxidation and biochemical treatment is then treated in an incinerator.

[0022] (3) Harmless treatment of butter and recycling of accompanying sand

[0023] The butter in the butter package and the recycled sand are fed to the sand-oil mixing feeder. The sand is heated and dehydrated in the front section of the sand-oil mixing feeder, and the sand and butter are stirred and mixed in the back section. The weight ratio of sand to butter is 5:1 to 12:1.

[0024] The sand-oil mixing feeder delivers the uniformly mixed and adhered sand and butter mixture to the incinerator, where it undergoes pyrolysis at a temperature between 650 and 800°C. The butter adhering to the surface of the sand is oxidized and decomposed at high temperature. The pyrolyzed sand and ash are then washed and desalted with demineralized water by a sand cooling and washing conveyor before being sent back to the sand-oil mixing feeder for recycling. The flue gas generated during incineration and pyrolysis passes through a high-temperature bag filter to intercept the tiny sodium salt and ash particles produced during pyrolysis before entering the secondary combustion chamber for incineration. After recovering heat energy through a waste heat boiler, the flue gas is then treated in sequence in a cooling tower and a spray tower before being discharged at high altitude after meeting emission standards.

[0025] Preferably, in step (1), under normal circumstances, the density of grease in the waste alkaline solution of the coal-to-olefins unit is slightly lower than that of the waste alkaline solution. Oil-water separation can be achieved by gravity separation. A portion of the waste alkaline solution that has been treated to remove grease is concentrated by vacuum evaporation and then mixed with the feed of the grease remover to increase the density of the waste alkaline solution and accelerate the oil-water separation speed.

[0026] Preferably, the waste alkaline solution from the coal-to-olefins unit in step (1) refers to a waste alkaline solution with sodium hydroxide (NaOH) between 1 and 2 wt%, sodium carbonate (Na2CO3) between 1.5 and 4 wt%, butter between 2500 and 6000 mg / L, chemical oxygen demand (COD) between 8000 and 20000 mg / L, TDS between 40000 and 80000 mg / L, and pH between 13 and 14.

[0027] Preferably, in step (1), the effective liquid level of the grease remover is not less than 5m; the surface hydraulic load is 0.03~0.1m. 3 / (m 2 (·h), with an optimal surface hydraulic loading of 0.05~0.06m. 3 / (m 2 •h); The grease package is integrated on the side wall of the grease remover and shares a grease inlet with the grease remover, avoiding long-distance transport;

[0028] The degreaser includes a waste alkali inlet, a waste alkali outlet, a grease outlet, vent a, vent b, a utility port, a temperature instrument port, a flange level gauge lower port, a flange level gauge upper port, a pressure instrument port, a breather valve port, a nitrogen seal port, an emergency vent, a waste gas outlet, an upper maintenance manhole, a lower maintenance manhole, an oil-water manifold, a water distribution ring pipe, a water collection ring pipe, an inlet connecting pipe, an outlet connecting pipe, a siphon breaking pipe, and sight glasses a, b, and c. The components include: a mirror (d), a drain level regulator, and a grease bag; the structure of the oil-water manifold in the grease remover includes an inlet, a water distribution ring pipe interface, a water collection ring pipe interface, an outlet, an inner cavity, and an annular jacket cavity; the structure of the drain level regulator includes a handwheel, a nut bracket, a lead screw, an O-ring, a siphon breaking interface, an inlet, an adjustable sleeve, and an outlet; the structure of the grease bag includes a manhole with a sight glass, a temperature instrument port, a grease drain port, a level instrument port, and a grease inlet port;

[0029] The diameter of the grease remover is D; the oil-water manifold is located in the center of the grease remover; the vertical height of the water distribution ring pipe from the bottom of the grease remover is H1, where H1 is 2.5~3m, and the water distribution ring pipe has evenly distributed upward-facing water distribution holes. The water distribution ring pipe is connected to the water distribution ring pipe interface of the oil-water manifold through three interconnecting pipes at 120° intervals. The water distribution ring pipe interface is connected to the liquid inlet of the grease remover through an annular jacket cavity. The liquid inlet of the grease remover is connected to the waste alkali liquid inlet through a water inlet connecting pipe; the water collection ring pipe is located at the bottom of the grease remover, with a vertical height of H2 from the bottom of the grease remover, where H2 is 0.4~0.8m, and the water collection ring pipe has evenly distributed downward-facing water collection holes. The water collection ring pipe is connected to the oil-water manifold through three interconnecting pipes at 120° intervals. The water collection ring pipe interface is connected, and the water collection ring pipe interface is connected to the outlet of the degreaser through the inner cavity. The outlet of the degreaser is connected to the outlet of the degreased waste alkali liquid through the water outlet connecting pipe. One end of the siphon breaking pipe is connected to the siphon breaking interface of the drainage level regulator, and the other end is connected to the gas phase space inside the degreaser to maintain the pressure balance between the degreased waste alkali liquid surface and the grease liquid surface. The grease outlet and the grease inlet of the grease bag are the same. The vertical distance between the lower edge of the grease outlet and the center of the water inlet of the adjustable sleeve in the drainage level regulator is Δh, which can be adjusted between 0.05 and 0.20 m. The vertical distance between the lower edge of the grease outlet and the oil-water interface is the oil layer thickness H, where H = ρ × Δh / Δρ; where ρ is the density of the waste alkali liquid, in kg / m³. 3 Δh is the difference between the lower edge elevation of the butter outlet and the center elevation of the adjustable sleeve inlet in the drain level regulator, in meters (m); Δρ is the density difference between the waste alkali solution and the butter, in kilograms per cubic meter of water. 3The sight glasses a-d are evenly distributed on the side wall of the grease remover, at a height of H along the oil layer thickness. The inlet of the drain level regulator is connected to the outlet of the grease remover's waste alkali solution. By adjusting the height of the adjustable sleeve, Δh is adjusted to control the oil layer thickness H. The grease pack is located on the side wall of the grease remover, sharing the same wall with it. The top of the grease remover is equipped with a pressure gauge port, a breather valve port, a nitrogen seal port, an emergency release port, a waste gas outlet, and an upper maintenance manhole. The side wall is equipped with a lower flange port for the level gauge, an upper flange port for the level gauge, a temperature instrument port, sight glasses a-d, and a lower maintenance manhole. The bottom is equipped with an vent.

[0030] Preferably, in step (1), the inner wall of the butter package and the inner wall of the butter delivery pipe are lined with an oleophobic material to reduce butter adhesion. The lining material is polytetrafluoroethylene (PTFE), silicone, fluorinated ethylene propylene copolymer (FEP), or perfluoroalkoxy resin (PFA). More preferably, the oleophobic lining material is polytetrafluoroethylene (PTFE).

[0031] Preferably, in step (1), the grease remover, grease bag and grease delivery pipeline are heated by steam heating, hot water heating or electric heating to maintain the internal temperature between 30 and 50°C.

[0032] Preferably, the grease remover, grease bag, and grease delivery pipeline are heated by electric heating; the temperature inside the grease remover and grease bag is maintained between 35 and 38°C; and the temperature inside the grease delivery pipeline is maintained between 40 and 45°C.

[0033] Preferably, in step (2a), the buffer tank one, buffer tank two, cooler, and ozone oxidation reactor are integrated devices.

[0034] Preferably, the integrated equipment is divided into three chambers from top to bottom: chamber A, chamber B, and chamber C. Chamber A is an ozone oxidation reactor, chamber B is a second buffer tank, and chamber C is a first buffer tank. Chamber A includes an inlet, an ozone inlet, an outlet, an air outlet, a bottom manhole, a top manhole, a waste gas outlet, a breather valve, a filter media unloading hole, a water distribution perforated pipe, a gas distribution perforated pipe, and filter media. Chamber B includes a biochemical water inlet, a backwash drainage inlet, an outlet, an air outlet, a waste gas outlet, an upper flange level gauge, a lower flange level gauge, and a manhole. Chamber C includes an inlet for grease-removing waste alkali solution, an inlet for cooling brine with accompanying sand, an outlet, an air outlet, a waste gas outlet, an upper flange level gauge, a lower flange level gauge, a temperature instrument port, a cooling water inlet, a cooling water outlet, a manhole, and a cooler.

[0035] The integrated device has a diameter of D, with an upper section (cavity A), a middle section (cavity B), and a lower section (cavity C). Cavity A has a top manhole, an exhaust outlet, and a breather valve at the top; its side walls have a water inlet, an ozone inlet, a water outlet, an air outlet, a bottom manhole, a filter media unloading hole, a water distribution perforated pipe, and an air distribution perforated pipe. The filter media is located in the middle of cavity A, with a layer height of 2.5-4m and a distance of more than 1.2m between the bottom of the filter media and the bottom of cavity A. The water distribution perforated pipe and the air distribution perforated pipe are located at the bottom of cavity A, with a distance of 0.3-0.5m between them. The side wall of chamber B is equipped with a biochemical water inlet, a backwash drainage inlet, a water outlet, a waste gas outlet, an upper flange level gauge inlet, a lower flange level gauge inlet, and a manhole; a vent is provided at the bottom. The side wall of chamber C is equipped with a waste alkali solution inlet for removing grease, a demineralized water inlet for the accompanying sand, a water outlet, a waste gas outlet, an upper flange level gauge inlet, a lower flange level gauge inlet, a temperature instrument port, a cooling water inlet, a cooling water outlet, and a manhole; a vent is provided at the bottom. The cooler is located at the lower part of chamber C (buffer tank one) and is connected to the cooling water inlet and cooling water outlet.

[0036] Preferably, in step (2a), an acidic substance is added to neutralize the pH value. The acidic substance is sulfuric acid, hydrochloric acid, or sodium bisulfate.

[0037] Preferably, the acidic substance used to adjust the pH of the neutralized waste alkaline solution is sulfuric acid.

[0038] Preferably, in step (2a), the degassing tank and the biochemical reactor are integrated devices.

[0039] The structure of the integrated equipment is divided into chamber A and chamber B from top to bottom. Chamber A is a degassing tank and chamber B is a biochemical reactor. Chamber A includes an ozone oxidation reactor water inlet, regulating water inlet, vent, outlet, exhaust gas outlet, and manhole. Chamber B includes a degassing tank water inlet, compressed air inlet, vent a, vent b, outlet, exhaust gas outlet, breather valve, dissolved oxygen meter port, manhole a, manhole b, floating plate packing, main gas distribution pipe, and branch gas distribution pipe.

[0040] The integrated device has a diameter of D, with the upper section being cavity A and the lower section being cavity B. Cavity A (degassing tank) has a waste gas outlet and a manhole at the top; the side wall has an ozone oxidation reactor inlet, a regulating water inlet, an air outlet, and a water outlet. Cavity B (biochemical reactor) has an inlet, a compressed air inlet, a water outlet, a waste gas outlet, a breather valve, a dissolved oxygen meter port, and a manhole on its side wall; the bottom has an air outlet. The floating disc packing is located in the middle of cavity B, with a packing density of 90~95v%. The main gas distribution pipe and branch gas distribution pipe are located in the lower part of cavity B, with the main gas distribution pipe 0.15~0.3m from the bottom of cavity B. The branch gas distribution pipe is connected to the main gas distribution pipe, and aeration holes at a 45° downward angle are evenly distributed on the branch gas distribution pipe.

[0041] Preferably, in step (2a), the antagonistic nutrient is potassium ions (K+). + The main component is glucose, with small amounts of nitrogen (N), phosphorus (P), and ferric or ferrous ions (Fe). 3+ or Fe 2+ ), magnesium (Mg) 2+ The antagonistic nutrient agent comprises ions and an aqueous solution using water as a solvent; preferably, when the antagonistic nutrient agent is added to the mixed wastewater, the dosage of each component satisfies the following:

[0042] The concentration of potassium ions added is 5~10 mg / L;

[0043] The concentration of ferric or ferrous ions added is 1~2 mg / L;

[0044] The concentration of magnesium ions added is 2~3 mg / L;

[0045] The glucose dosage is 20 wt% of the total COD in the mixed wastewater;

[0046] The nitrogen dosage is 2.5 wt% of the total COD in the mixed wastewater;

[0047] The amount of phosphorus added is 0.5 wt% of the total COD in the mixed wastewater.

[0048] Preferably, in step (2b), the post-ozone reactor, post-degassing tank, aerated biological filter and monitoring pool are integrated devices.

[0049] The integrated equipment is structured from top to bottom as follows: Chamber A, Chamber B, Chamber C, and Chamber D. Chamber A is the post-ozone reactor, including a filter inlet, ozone inlet, outlet, vent, bottom manhole, top manhole, exhaust gas outlet, breather valve, filter media unloading hole, water distribution perforated pipe, air distribution perforated pipe, and filter media. Chamber B is the post-degassing tank, including a post-ozone reactor inlet, outlet, exhaust gas outlet, vent, and manhole. Chamber C is the aerated biological filter, including a post-degassing tank inlet, outlet, compressed air inlet, backwash drain, exhaust gas outlet, breather valve, dissolved oxygen meter port, manhole a, manhole b, filter media unloading hole, pressure meter port, vent, water distribution perforated pipe, air distribution perforated pipe, and filter media. Chamber D is the monitoring tank, including an aerated biological filter inlet, outlet, vent, exhaust gas outlet, upper flange level gauge port, lower flange level gauge port, and manhole.

[0050] The integrated device has a diameter of D, with the upper section being cavity A, the middle sections being cavities B and C, and the lower section being cavity D. Cavity A has an exhaust gas outlet, a breather valve, and a manhole at the top; its side walls have a candle filter inlet, an ozone inlet, an outlet, a manhole, a filter media discharge port, a water distribution perforated pipe, and a gas distribution perforated pipe; and a vent at the bottom. The filter media is located in the middle of cavity A, with a filter media layer height of 2.5~4m, and the bottom of the filter media is more than 1.2m above the bottom of cavity A. The water distribution perforated pipe and the gas distribution perforated pipe are located at the lower part of cavity A, with a distance of 0.3~0.5m between them. Cavity B has an ozone reactor inlet, an outlet, an exhaust gas outlet, and a manhole on its side walls; and a vent at the bottom. The C chamber has the following features: a rear degassing tank inlet, outlet, compressed air inlet, backwash drain outlet, exhaust gas outlet, breather valve outlet, dissolved oxygen meter outlet, manhole, filter media unloading hole, pressure meter outlet, water distribution perforated pipe, and air distribution perforated pipe; an exhaust port is located at the bottom; the filter media is located in the middle of the C chamber, with a filter media layer height of 2.5~4m and a bottom height of more than 1.2m from the bottom of the C chamber; the water distribution perforated pipe and air distribution perforated pipe are located at the bottom of the C chamber, with a distance of 0.3~0.5m between them; the D chamber has the aerated biological filter inlet, outlet, exhaust gas outlet, upper flange level gauge outlet, lower flange level gauge outlet, and manhole on its side wall; an exhaust port is located at the bottom.

[0051] Preferably, in step (3), the pyrolysis time of the incinerator is 1 to 2 hours and the pyrolysis temperature is 650 to 800°C; more preferably, the pyrolysis temperature of the incinerator is 680 to 750°C.

[0052] Preferably, in step (3), the accompanying sand can be quartz sand, river sand, ceramic sand or metal sand; the particle size is between 0.1 and 5 mm; the Mohs hardness is not less than 5; and the melting point is not less than 900°C.

[0053] Preferably, the particle size of the accompanying sand is between 0.2 and 1.5 mm; the Mohs hardness is not less than 6; and the melting point is not less than 1200°C; more preferably, the accompanying sand is quartz sand.

[0054] Preferably, in step (3), the sand-oil mixing feeder integrates the dehydration of the recycled sand, the mixing with butter, and the incinerator feed into one unit; first, the sand is indirectly heated by steam generated by a waste heat boiler in the conveying section with a jacket layer to dehydrate it; second, the dehydrated sand is mixed with butter in proportion through the mixing conveying section; and finally, it is sent to the incinerator feed port.

[0055] Preferably, the sand-oil mixing feeder has a structure including a mixing feeder auger end shaft, bearing cover, bracket, oil seal cover, seat cover, copper sleeve, auger shell end flange, sand inlet, auger shell, blades, auger shaft, grease inlet inspection box, gravity seal cover, grease inlet, grease and sand mixture outlet, rear end cover, oil seal cover II, steam jacket, steam inlet, condensate outlet, and gas phase outlet.

[0056] Preferably, in step (3), the sand cooling and washing conveyor integrates the cooling, washing and conveying of the recycled sand; firstly, in the horizontal conveying section, washing water enters on one side and overflows on the other side to cool and wash the sand; secondly, the recycled sand is sent to the sand-oil mixing feeder for reuse through the rear buried scraper.

[0057] Preferably, the sand cooling and salt washing conveyor has a structure including a sand washing water outlet, a water tank, an overflow baffle, a tail section, a driven wheel, a tail inspection port, a feeding section, an inlet for recycled sand from the incinerator, a sand washing water inlet, a lower curved section, an inspection port for the lower curved section, an inspection port at the back of the lower curved section, a vertical section, an upper curved section, an inspection port for the upper curved section, a head section, a head inspection port, an outlet for the cooled and desalinated sand, and a driving wheel.

[0058] Preferably, in step (3), a high-temperature bag filter is installed in the pyrolysis section and the secondary combustion chamber section of the incinerator to intercept tiny sodium salt particles and fly ash generated during the pyrolysis process; the flue gas from the secondary combustion chamber first passes through a waste heat boiler to recover heat energy for dehydration and heating of the accompanying sand; after being treated by a cooling tower and a spray tower, it meets the standards and is discharged into the air through a chimney.

[0059] Preferably, the high-temperature bag filter is a high-temperature metal fiber bag filter with a temperature resistance of not less than 750℃.

[0060] Compared with the prior art, the method of the present invention has the following beneficial effects:

[0061] 1. For coal-to-olefins waste alkaline liquor, the main problems with current industrialized treatment processes are grease clogging at the front end and clogging of nozzles and low-temperature sections in incineration methods. This invention employs multiple measures to effectively solve these clogging problems. First, under nitrogen-sealed conditions, multiple heating points (grease remover, grease bag, grease conveying line, and nitrogen-sealed air inlet line) improve the fluidity of the grease. A specially designed separation device performs non-powered separation of the grease from the waste alkaline liquor. The grease bag and grease conveying pipes are lined with oleophobic materials to prevent grease adhesion and clogging during transport. Second, the separated grease is mixed with accompanying sand in a specific ratio and fed into the incinerator for high-temperature pyrolysis using a sand-frying method. Due to the stability and uniform heating of the selected accompanying sand at high temperatures, the grease is heated evenly during pyrolysis, does not stick to the furnace wall, oxidizes thoroughly, and no carbon black is formed. Furthermore, the pyrolysis temperature is controlled below the melting point of sodium carbonate (851℃) to avoid the formation of molten salt, effectively solving the clogging problem.

[0062] 2. The method of the present invention mainly uses butter and accompanying sand in the incineration process. Compared with the conventional direct incineration of waste alkali liquid, the incineration volume is small, the calorific value is high, the fuel consumption is small, and the energy consumption is low. At the same time, the accompanying sand regenerated by incineration can be reused twice, the replenishment amount is small, and no solid waste is generated in the whole process.

[0063] 3. The method of the present invention can treat coal-to-olefins waste alkaline liquid to meet standards. After treatment, the effluent indicators can reach COD < 50 mg / L; suspended solids < 50 mg / L; petroleum < 3 mg / L; pH 6-9. Attached Figure Description

[0064] Figure 1 This is a flowchart of a method for treating waste alkaline solution from a coal-to-olefins plant to meet standards, according to the present invention.

[0065] Figure 2 This invention provides a process flow diagram for treating waste alkaline liquor from coal-to-olefins processes to remove grease and ensure compliant discharge of waste alkaline liquor.

[0066] Figure 3 This is a process flow diagram of the harmless treatment of butter and the regeneration of accompanying sand according to the present invention;

[0067] Figure 4 This is an elevation view of the grease remover of the present invention;

[0068] Figure 5 This is an elevation view of the oil-water manifold in the grease remover of the present invention;

[0069] Figure 6 This is a schematic diagram of the drain level regulator at the outlet of the grease remover of the present invention.

[0070] Figure 7 This is a plan view of the water distribution ring pipe in the grease remover of the present invention;

[0071] Figure 8 This is a plan view of the water collection ring pipe in the grease remover of the present invention;

[0072] Figure 9 This is an elevation view of the integrated device 1 (including buffer tank 1, buffer tank 2, ozone oxidation reactor and cooler) in this invention;

[0073] Figure 10 This is an elevation view of the integrated device 2 (including a degassing tank and a biochemical reactor) in this invention;

[0074] Figure 11 This is an elevation view of the integrated equipment three (including a post-ozone reactor, a post-degassing tank, an aerated biological filter, and a monitoring water tank) in this invention;

[0075] Figure 12 This is a schematic diagram of the sand-oil mixing feeder structure in this invention;

[0076] Figure 13 This is a schematic diagram of the sand cooling and salt washing conveyor in this invention.

[0077] Explanation of reference numerals in the attached figures:

[0078] Grease remover-1, Waste alkali inlet-101, Waste alkali outlet for grease removal-102, Grease outlet-103, Drain port a-104, Drain port b-105, Utility port-106, Temperature instrument port-107, Flange level gauge lower port-108, Flange level gauge upper port-109, Pressure instrument port-110, Breather valve port-111, Nitrogen seal port-112, Emergency vent port-113, Exhaust gas outlet-114, Upper maintenance manhole-115, Lower maintenance manhole-116, Oil-water manifold-117, Water distribution ring pipe-118, Water collection ring pipe-119, Inlet connecting pipe-120, Outlet connecting pipe-121, Siphon breaking pipe-122, Sight glass a-134, Sight glass b-1 35. Sight glass c-136, Sight glass d-137; Liquid inlet-123, Water distribution ring pipe interface-124, Water collection ring pipe interface-125, Liquid outlet-126, Inner cavity-127, Annular jacket cavity-128; Drainage level regulator-138, Handwheel-139, Nut bracket-140, Screw-141, O-ring-142, Siphon breaking interface-143, Liquid inlet-144, Adjustable sleeve-145, Liquid outlet-146; Grease pack-133, Manhole with sight glass-147, Temperature instrument port-148, Grease drain port-149, Liquid level instrument port-150, Grease inlet-151, Integrated device-3, Water inlet-301, Ozone inlet-302, Water outlet Manhole-303, Drain-304, Bottom Manhole-305, Top Manhole-306, Exhaust Gas Outlet-307, Breather Valve-308, Filter Material Discharge Hole-309, Water Distribution Perforated Pipe-310, Air Distribution Perforated Pipe-311, Filter Material-312; Biochemical Water Inlet-313, Backwash Drainage Inlet-314, Water Outlet-315, Exhaust Gas Outlet-317, Flange Level Gauge Upper Inlet-318, Flange Level Gauge Lower Inlet-319, Manhole-320, Drain-316, Degreased Alkali Liquid Inlet-321, Accompanying Sand Demineralized Water Washing Water Inlet-322, Water Outlet-323, Exhaust Gas Outlet-325, Flange Level Gauge Upper Inlet-326, Flange Level Gauge Lower Inlet-327, Temperature Instrument Port -328, Cooling water inlet -329, Cooling water outlet -330, Manhole -331, Drain -324, Cooler -332, Integrated equipment -4, Ozone oxidation reactor inlet -401, Adjusting water inlet -402, Drain -403, Outlet -404, Exhaust gas outlet -405, Manhole -406, Degassing tank inlet -407, Compressed air inlet -408, Drain a -409, Drain b -410, Outlet -411, Exhaust gas outlet -412, Breathing valve port -413, Dissolved oxygen instrument port -414, Manhole a -415, Manhole b -416, Floating disc packing -417, Main gas distribution pipe -418, Branch gas distribution pipe -419;Integrated Equipment - 5, Candle Filter Inlet - 501, Ozone Inlet - 502, Outlet - 503, Exhaust Outlet - 504, Manhole - 505, Manhole - 506, Exhaust Gas Outlet - 507, Breathing Valve - 508, Filter Media Discharge Hole - 509, Water Distribution Perforated Pipe - 510, Air Distribution Perforated Pipe - 511, Filter Media - 512, Ozone Reactor Inlet - 513, Outlet - 514, Exhaust Gas Outlet - 515, Manhole - 517, Exhaust Outlet - 516, Post-Degassing Tank Inlet - 518, Outlet - 519, Compressed Air Inlet - 520, Backwash Drain - 521, Exhaust Gas Outlet - 522, Breathing Valve - 523, Dissolved Oxygen Meter Port - 524, Manhole - 525, 526, Filter Media Discharge Hole-527, Pressure gauge port-528, Water distribution perforated pipe-530, Air distribution perforated pipe-531, Exhaust port-529; Filter media-532, Aerated biological filter inlet-533, Outlet-534, Exhaust gas outlet-536, Flange level gauge upper port-537, Flange level gauge lower port-538, Manhole-539, Exhaust port-535, Sand-oil mixer feeder-6, Mixer feeder auger end shaft-601, Bearing cover-602, Bracket-603, Oil seal cover-604, Seat cover-605, Copper sleeve-606, Auger housing end flange-607, Accompanying sand inlet-608, Auger housing-609, Blade-610, Auger shaft-611, Grease inlet inspection box-612, Gravity seal cover- 613. Butter Inlet - 614. Butter and Mixed Sand Mixture Outlet - 615. Rear End Cover - 616. Oil Seal Cover II - 617. Steam Jacket - 618. Steam Inlet - 619. Condensate Outlet - 620. Vapor Phase Outlet - 621. Sand Cooling and Salt Washing Conveyor - 7. Sand Washing Water Outlet - 701. Water Tank - 702. Overflow Baffle - 703. Tail - 704. Driven Wheel - 705. Tail Inspection Port - 706. Feed Section - 707. Inlet for Regenerated Mixed Sand from Incinerator - 708. Sand Washing Water Inlet - 709. Lower Bending Section - 710. Lower Bending Section Inspection Port - 711. Lower Bending Section Back Inspection Port - 712. Vertical Section - 713. Upper Bending Section - 714. Upper Bending Section Inspection Port - 715. Head -716, Head Inspection Port -717, Cooling and Desalination Post-Containing Sand Outlet -718, Drive Wheel -719, Grease Delivery Pump -8, Buffer Tank I Lift Pump -9, Ozone Generator -10, Pipeline Mixer -11, Buffer Tank II Lift Pump -12, Filter -13, Sulfuric Acid Dosing Pack -14, Antagonistic Nutrient Dosing Pack -15, Backwash Water Pump -16, Exhaust Gas Fan -17, Pyrolysis Incinerator -18, Pyrolysis Incinerator Oxygenation Fan -19, Cooling Wash Brine Lift Pump -20, High-Temperature Metal Fiber Bag Filter -21, Secondary Combustion Chamber -22, Secondary Combustion Chamber Oxygenation Fan -23, Urea Dosing Pack -24, Waste Heat Boiler -25, Spray Tower -26, Water Tank -27, Spray Water Circulation Pump -28, Exhaust Fan -29, Chimney -30. Detailed Implementation

[0079] The present invention will be further described in detail below with reference to the embodiments.

[0080] The following examples illustrate the implementation process of the method of the present invention in more detail. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Without substantial changes to the technical content, it should also be considered within the scope of the present invention.

[0081] Example 1: Screening quartz sand for butter mixture

[0082] Waste alkaline liquid from the coal-to-olefins unit of a coal chemical enterprise was collected. This waste alkaline liquid was discharged from the alkaline washing tower of the coal-to-olefins unit. After standing for 48 hours, a layer of viscous, brownish-yellow solid polymer, commonly known as "butter," appeared on the surface of the liquid in the sampling bucket.

[0083] Weigh 2g of the above-mentioned butter into 6 crucibles respectively. Add 8g of quartz sand with a particle size of 0.1~0.4mm to crucible #1, 10g of quartz sand with a particle size of 0.1~0.4mm to crucible #2, 8g of quartz sand with a particle size of 0.2~1.5mm to crucible #3, 10g of quartz sand with a particle size of 0.2~1.5mm to crucible #4, 8g of quartz sand with a particle size of 1.5~5mm to crucible #5, and 10g of quartz sand with a particle size of 1.5~5mm to crucible #6.

[0084] The water bath temperature of the six crucibles was maintained at 40℃. They were stirred and mixed with glass rods. Sample 4 had moderate stirring resistance, good uniformity, and did not stick to the crucible. Sample 3 had moderate stirring resistance, good uniformity, and slightly stuck to the crucible. Samples 5 and 6 had low stirring resistance, average uniformity, and the butter stuck to the crucible. Samples 1 and 2 had high stirring resistance, good uniformity, and the butter did not stick to the crucible.

[0085] This embodiment illustrates that the weight ratio of quartz sand to butter should be greater than 5:1, and the preferred particle size of the quartz sand is 0.2~1.5mm.

[0086] Example 2: Pyrolysis of oil-sand mixture

[0087] Weigh 2g of the above-mentioned butter into five crucibles, add 10g of quartz sand with a particle size of 0.2~1.5mm, maintain the water bath temperature at 45℃, stir evenly with a glass rod, and place in a muffle furnace for pyrolysis. Control the temperature at 600℃, 650℃, 700℃, 750℃, and 800℃ respectively, and the pyrolysis time is 1 hour for each. After pyrolysis, add 100mg / L water to wash the sand, and analyze the COD of the filtrate.

[0088] Table 1 COD values ​​of sand washing water filtrate after pyrolysis

[0089]

[0090] The results are shown in Table 1. Sample #7, after pyrolysis at 600℃, contained black solids in its ash, some of which adhered to the crucible wall, indicating incomplete pyrolysis and the production of carbon black. If carbon black enters the system, it will accumulate and adversely affect the treatment system. The filtrate also has a high COD value, making direct discharge impossible during engineering implementation. Samples #8 to #11, at pyrolysis temperatures of 650℃ to 800℃, did not contain black solids in their ash, did not adhere to the wall, and the COD values ​​of the filtrates obtained after dissolution and filtration were all less than 10 mg / L. Therefore, 650℃ to 800℃ was selected as the pyrolysis control temperature for the rotary kiln.

[0091] Example 3: COD removal by ozone oxidation at different dilution ratios

[0092] The waste alkaline solution after removing the butter in Example 1 was analyzed for its components, and the results are shown in Table 2 below.

[0093] Table 2. Composition Information of Waste Alkali Solution

[0094]

[0095] “CODcr” represents chemical oxygen demand; “TDS” represents total dissolved solids (which may also be referred to as salt in this application).

[0096] The above-mentioned waste alkaline solution was diluted with distilled water by 2, 3, and 4 times respectively. 150 mL of each solution was then taken and oxidized with ozone for 1 hour at a concentration of 100 mg / L and a flow rate of 0.1 L / min. The COD values ​​after oxidation are shown in Table 3 below.

[0097] Table 3 COD values ​​(mg / L) after ozone oxidation at different dilution ratios

[0098]

[0099] The COD removal rate was 0.406 g / h after a 2-fold dilution, 0.350 g / h after a 3-fold dilution, and 0.305 g / h after a 4-fold dilution. The 2-fold dilution resulted in the highest COD removal rate. With an ozone dosage of 0.6 g / h and an oxidation time of 1 hour, the ozone-to-COD ratios after 2-fold, 3-fold, and 4-fold dilutions were 1.48:1, 1.72:1, and 1.97:1, respectively.

[0100] This example illustrates that a 2-fold dilution of COD results in the highest removal rate, while the ratio of ozone to COD is the lowest. During project implementation, ozone oxidation treatment should be performed after diluting the COD by 2-3 times, depending on the actual situation.

[0101] Example 4: Treatment of Waste Alkali Solution to Meet Standards

[0102] Take the waste alkaline solution after removing the butter from Example 1, dilute it 5 times, and oxidize it with ozone for 4 hours (because the ozone generator is too small, the reaction time is extended to reduce the COD to the expected value). The COD is 734 mg / L. Neutralize with sulfuric acid and adjust the pH to 8. Take the wastewater after ozone oxidation for biochemical experiments.

[0103] Activated sludge from a wastewater treatment plant was used for cultivation, acclimatization, and biochemical experiments. In a 2L graduated cylinder, 500mL of the ozone-oxidized waste alkaline solution was added, along with a certain amount of sludge (sludge concentration controlled at 4000mg / L). The volume was adjusted to 1.8L with clean water, and 1g of glucose and 2mL of antagonistic nutrient were added. The water bath temperature was maintained at 32℃, and aerobic biochemical treatment was carried out for 16 hours. The COD of the filtrate was analyzed. Then, the top 1.3L of supernatant was discarded, and 760mL of waste alkaline solution, 0.8g of glucose, and 2mL of antagonistic nutrient were added, bringing the volume to 1.8L and aeration continued for 16 hours. Afterward, the glucose volume was reduced by 0.2g and the waste alkaline solution volume increased by 260mL daily. After 5 days, glucose was discontinued, and the sludge cultivation and acclimatization were complete. The antagonistic nutrient was potassium ions (K... + The main component is glucose, with small amounts of nitrogen (N), phosphorus (P), and ferric or ferrous ions (Fe). 3+ or Fe 2+ ), magnesium (Mg) 2+ The dosage of each component, including potassium ions and water-based aqueous solutions, meets the following requirements: potassium ion concentration of 5-10 mg / L, ferric or ferrous ion concentration of 1-2 mg / L, magnesium ion concentration of 2-3 mg / L, glucose dosage of 20 wt% of the total COD in the mixed wastewater, nitrogen dosage of 2.5 wt% of the total COD in the mixed wastewater, and phosphorus dosage of 0.5 wt% of the total COD in the mixed wastewater.

[0104] By operating the waste alkaline solution for 3 days, the COD was reduced from 600~650mg / L to 240~360mg / L through biochemical treatment.

[0105] After filtering 1L of the biochemical supernatant, ozone oxidation was carried out for 1 hour at an ozone concentration of 100mg / L and a flow rate of 0.1L / min, reducing the COD to about 80mg / L. Biochemical treatment was continued for another 3 hours, reducing the COD to 30~50mg / L.

[0106] This example illustrates that the waste alkaline solution after removing the butter is diluted 5 times, and after ozone oxidation and biochemical treatment, the COD is reduced to less than 400 mg / L. After another ozone oxidation and biochemical treatment, the COD can be reduced to less than 50 mg / L.

[0107] Example 5: Pilot-scale test of waste alkali solution treatment and grease harmless treatment

[0108] Figure 1This is a flowchart of a method for treating waste alkaline solution from a coal-to-olefins plant to meet standards, according to the present invention. Figure 2 This invention relates to a process flow diagram for removing grease from waste alkaline liquor and treating waste alkaline liquor in coal-to-olefins production. Figure 3 This is a flowchart of the process for harmless treatment of butter and regeneration of accompanying sand according to the present invention.

[0109] (1) Removal of butter

[0110] Waste alkali liquid is introduced into a degreasing unit from the alkali washing tower pipeline of a coal chemical plant. Through specially designed internal components, the density difference between the grease and the waste alkali liquid causes them to separate into two layers: the upper part of the degreasing unit contains grease, and the lower part contains the degreased waste alkali liquid. The separated grease flows by gravity to a grease bag for collection, while the degreased waste alkali liquid is sent to a buffer tank via a drainage level regulator. The degreasing unit, grease bag, and grease delivery pipeline are heated electrically to maintain the temperature inside the degreasing unit and grease bag between 35 and 38°C; the temperature inside the grease delivery pipeline is maintained between 40 and 45°C; and the waste alkali liquid flow rate is controlled at 0.5 m³ / min. 3 / h.

[0111] Under normal circumstances, the density of grease in the waste alkaline solution of coal-to-olefins plant is slightly lower than that of the waste alkaline solution. Oil and water can be separated by gravity separation. If it is necessary to speed up the oil-water separation, a portion of the waste alkaline solution that has undergone grease removal treatment can be concentrated by vacuum evaporation and then mixed with the feed of the grease remover to increase the density of the waste alkaline solution and speed up the oil-water separation.

[0112] The degreaser 1 adopts the principle of communicating vessels and uses specially designed internal components to perform fully automatic hydraulic degreasing by utilizing the density difference between grease and waste alkali solution. The liquid level regulator 138 with a special structure is used to adjust the liquid level height at the outlet of the degreaser waste alkali solution. The grease bag 133 is integrated on the side wall of the degreaser and shares a grease outlet with the degreaser to avoid long-distance transportation.

[0113] Figure 4 This is an elevation view of the grease remover of the present invention; Figure 5 This is an elevation view of the oil-water manifold in the grease remover of the present invention; Figure 6 This is a schematic diagram of the drain level regulator at the outlet of the grease remover of the present invention. Figure 7 This is a plan view of the water distribution ring pipe in the grease remover of the present invention; Figure 8This is a plan view of the water collection ring pipe in the grease remover of the present invention. The grease remover 1 includes a waste alkali inlet 101, a waste alkali outlet 102, a grease outlet 103, an vent a 104, an vent b 105, a utility port 106, a temperature instrument port 107, a flange level gauge lower port 108, a flange level gauge upper port 109, a pressure instrument port 110, a breather valve port 111, a nitrogen sealing port 112, an emergency vent 113, a waste gas outlet 114, an upper maintenance manhole 115, a lower maintenance manhole 116, an oil-water manifold 117, a water distribution ring pipe 118, a water collection ring pipe 119, a water inlet connecting pipe 120, a water outlet connecting pipe 121, a siphon breaking pipe 122, and sight glasses a 134, b 135, c 136, and d. 137. Drainage level regulator 138. Grease pack 133; The structure of the oil-water manifold 117 in the grease remover 1 includes an inlet 123, a water distribution ring pipe interface 124, a water collection ring pipe interface 125, an outlet 126, an inner cavity 127, and an annular jacket cavity 128; The structure of the drainage level regulator 138 includes a handwheel 139, a nut bracket 140, a lead screw 141, an O-ring 142, a siphon breaking interface 143, an inlet 144, an adjustable sleeve 145, and an outlet 146; The structure of the grease pack 133 includes a manhole with a sight glass 147, a temperature instrument port 148, a grease discharge port 149, a level instrument port 150, and a grease inlet 151;

[0114] The diameter of the degreaser 1 is D; the oil-water manifold 117 is located in the center of the degreaser 1; the vertical height of the water distribution ring pipe 118 from the bottom of the degreaser 1 is H1, where H1 is 2.5~3m; the water distribution ring pipe 118 has evenly distributed upward-facing water distribution holes 130; the water distribution ring pipe 118 is connected to the water distribution ring pipe interface 124 of the oil-water manifold 117 through three connecting pipes 129 at 120° intervals; the water distribution ring pipe interface 124... 24 is connected to the liquid inlet 123 through the annular interlayer cavity 128, and the liquid inlet 123 is connected to the waste alkali liquid inlet 101 through the water inlet connecting pipe 120; the water collecting ring pipe 119 is located at the lower part of the degreaser 1, and the vertical height from the bottom of the degreaser 1 is H2, where H2 is 0.4~0.8m. The water collecting ring pipe 119 has downward-facing water collection holes evenly distributed on it, and the water collecting ring pipe 119 is connected to three connecting pipes 131 at 120° to each other. The oil-water manifold 117 is connected to the water collection ring interface 125. The water collection ring interface 125 is connected to the liquid outlet 126 through the inner cavity 127. The liquid outlet 126 is connected to the degreased waste alkali liquid outlet 102 through the water outlet connecting pipe 121. One end of the siphon breaking pipe 122 is connected to the siphon breaking interface 143 of the drainage level regulator 138, and the other end is connected to the gas phase space inside the degreaser 1 to maintain the pressure balance between the degreased waste alkali liquid surface and the grease liquid surface. The grease outlet 103 and the grease inlet 151 of the grease bag 133 are the same outlet. The vertical distance between the lower edge of the grease outlet 103 and the center of the water inlet of the adjustable sleeve 145 in the drainage level regulator 138 is Δh, which can be adjusted between 0.05 and 0.20 m. The vertical distance between the lower edge of the grease outlet 103 and the oil-water interface is the oil layer thickness H, where H = ρ × Δh / Δρ (ρ: density of waste alkali liquid / kg / m³). 3 Δh: The difference between the lower edge elevation of the butter outlet and the center elevation of the adjustable sleeve inlet in the drain level regulator (m); Δρ: The density difference between the waste alkali solution and the butter (kg / m³). 3 The sight glasses 134-137 are evenly distributed on the side wall of the grease remover 1 at a height of H along the oil layer thickness; the inlet 144 of the drain level regulator 138 is connected to the outlet 102 of the grease removal waste alkali liquid of the grease remover 1, and the oil layer thickness H is controlled by adjusting the height of the adjustable sleeve 145 and adjusting Δh; the grease pack 133 is located on the side wall of the grease remover 1 and shares the same wall with the grease remover 1; the top of the grease remover 1 is provided with a pressure gauge port 110, a breather valve port 111, a nitrogen sealing port 112, an emergency release port 113, an exhaust gas outlet 114, and an upper maintenance manhole 115; the side wall is provided with a level gauge lower flange port 108, a level gauge upper flange port 109, a temperature instrument port 107, sight glasses 134-137, and a lower maintenance manhole 116; the bottom is provided with vent ports 104 and 105.

[0115] The degreasing device measures φ2.8×6m. Waste alkali solution is distributed into the degreasing device via an oil-water manifold. The grease-containing waste alkali solution is left to stand in the tank, where the grease accumulates at the top. The waste alkali solution is collected through a bottom ring pipe and enters the central pipe of the oil-water manifold. From the waste alkali solution outlet, the drainage level is adjusted by a drain level regulator to control the Δh at 0.06m. The waste alkali solution is then discharged into buffer tank one, with a surface hydraulic load of 0.08m. 3 / (m 2 •h). A 0.3m line is drawn from the outlet of the grease remover. 3 The waste alkaline solution after removing the grease was evaporated and concentrated at a rate of / h, yielding a concentrate of 0.06m³. 3 / h, the reflux is returned to the feed line of the grease remover, and the evaporated condensate is discharged to the evaporation and concentration water inlet point of the grease remover outlet line. After grease removal, the density of the waste alkaline solution increases to 1096 kg / m³. 3 This increases the density difference between the butter and the waste lye solution, making it easier to remove the butter. After 11 days, the butter that has accumulated at the top flows by gravity through the butter outlet to the butter package.

[0116] The inner walls of the butter package and the inner walls of the butter delivery pipe are lined with an oleophobic material to reduce butter adhesion. The lining material is polytetrafluoroethylene (PTFE), silicone, fluorinated ethylene propylene copolymer (FEP), or perfluoroalkoxy resin (PFA); preferably, the oleophobic lining material is polytetrafluoroethylene (PTFE).

[0117] (2) Treatment of waste alkaline solution to meet standards

[0118] The composition information of the waste alkali solution in the feed pipeline of the buffer tank after removing the grease was analyzed, and the results are shown in Table 4 below.

[0119] Table 4. Composition Information of Waste Alkali Solution

[0120]

[0121] “CODcr” represents chemical oxygen demand; “TDS” represents total dissolved solids (which may also be referred to as salt in this application).

[0122] (2a) Pretreatment of waste alkaline solution

[0123] The waste alkaline solution obtained after step (1) is treated with 1 to 1.5 times the weight of the waste alkaline solution and diluted with cooling brine containing sand. The solution is mixed in a buffer tank, cooled, and then sent to an ozone oxidation reactor. Ozone is introduced to break down the chains of the organic matter in the waste alkaline solution and oxidize it with ozone, thereby improving the biodegradability of the waste alkaline solution. The effluent from the ozone oxidation reactor is neutralized with acidic substances and sent to a degassing tank for degassing. The cooling brine containing sand is the water used in step (3) for cooling and washing the sand from the incinerator. The sodium carbonate content is less than 1% and the COD is less than 10 mg / L.

[0124] The effluent from the degassing tank is mixed with the conditioning water and then enters the biochemical reactor. The total dissolved solids (TDS) of the mixed wastewater is controlled at 12,000~18,000 mg / L. At the same time, antagonistic nutrients are added in proportion, air is blown in, and biochemical treatment is carried out. Organic pollutants in the mixed wastewater are removed by aerobic microorganisms, and the treated effluent is discharged to buffer tank two.

[0125] The buffer tank 1, buffer tank 2, cooler, and ozone oxidation reactor are integrated into a single integrated device. Figure 9 This is an elevation view of the integrated equipment (including buffer tank 1, buffer tank 2, ozone oxidation reactor and cooler).

[0126] The integrated device 1 has the structure of integrated device 3, and is divided into three chambers from top to bottom: chamber A (ozone oxidation reactor), chamber B (buffer tank 2), and chamber C (buffer tank 1). Chamber A (ozone oxidation reactor) includes an inlet 301, an ozone inlet 302, an outlet 303, an exhaust outlet 304, a bottom manhole 305, a top manhole 306, a waste gas outlet 307, a breather valve 308, a filter media discharge hole 309, a water distribution perforated pipe 310, a gas distribution perforated pipe 311, and filter media 312. Chamber B (buffer tank 2) has a biochemical water inlet 313, a backwash drainage inlet 314, an outlet 315, and a waste gas outlet 312 on its side wall. Gas outlet 317, flange level gauge upper inlet 318, flange level gauge lower inlet 319, manhole 320; vent 316 is provided at the bottom; the side wall of cavity C (buffer tank one) is provided with grease removal waste alkali inlet 321, accompanying sand demineralized water washing water inlet 322, water outlet 323, waste gas outlet 325, flange level gauge upper inlet 326, flange level gauge lower inlet 327, temperature instrument port 328, cooling water inlet 329, cooling water outlet 330, manhole 331; vent 324 is provided at the bottom; the cooler 332 is located at the lower part of cavity C (buffer tank one) and is connected to cooling water inlet 329 and cooling water outlet 330.

[0127] The buffer tank has a specification of φ1.4×2m, and contains waste alkali solution of butter and 1m 3 The cooled wash brine is mixed in a buffer tank at a rate of / h and then pumped to the ozone oxidation reactor.

[0128] The ozone oxidation reactor feed line is equipped with a coil cooler (integrated into buffer tank 1), using circulating cooling water to maintain the temperature of the waste alkaline solution at approximately 30°C. The ozone oxidation reactor has dimensions of φ1.4×7m, and the ozone dosage is set at 92 Nm³ for a concentration of 100 mg / L. 3 Ozone is aerated using perforated pipes at a rate of / h. The hydraulic retention time of the ozone oxidation reactor is 6 hours, and the effluent flows by gravity to the deaeration tank. The COD index of the effluent from the ozone oxidation reactor is shown in Table 5 below:

[0129] Table 5. Influent and Effluent Data of Ozone Oxidation Reactor (Unit: mg / L)

[0130]

[0131] The degassing tank and biochemical reactor are integrated into a second integrated device, which has the same structure as the fourth integrated device. Figure 10 This is an elevation view of the integrated device 4 (including a degassing tank and a biochemical reactor) of the present invention. The diameter is D. The upper section is chamber A (degassing tank), and the lower section is chamber B (biochemical reactor). Chamber A (degassing tank) has a waste gas outlet 405 and a manhole 406 at its top; its side wall has an ozone oxidation reactor water inlet 401, a regulating water inlet 402, an air outlet 403, and a water outlet 404. Chamber B (biochemical reactor) has a water inlet 407, a compressed air inlet 408, a water outlet 411, a waste gas outlet 412, and a breather valve on its side wall. The reactor includes a port 413, a dissolved oxygen meter port 414, and manholes 415 and 416; vents 409 and 410 are located at the bottom; the floating plate packing 417 is located in the middle of chamber B (biochemical reactor), with a packing density of 90-95%; the main gas distribution pipe 418 and the branch gas distribution pipe 419 are located at the bottom of chamber B (biochemical reactor), with the main gas distribution pipe 418 0.15-0.3m from the bottom of chamber B (biochemical reactor); the branch gas distribution pipe 419 is connected to the main gas distribution pipe 418, and aeration holes at a 45° downward angle are evenly distributed on the branch gas distribution pipe 419.

[0132] The degassing tank is integrated into the upper part of the biochemical reactor, with specifications of φ2.5×2m. A pipeline mixer is installed in the feed pipeline of the degassing tank. Concentrated sulfuric acid is added to the pipeline mixer to adjust the pH of the wastewater to 7-8. The dosage of 98% sulfuric acid is 9 kg / h. After neutralization, the TDS of the wastewater is 19000 mg / L. Conditioning water is introduced into the degassing tank. The conditioning water is the enterprise's circulating wastewater discharge. The conditioning water has a COD between 200-400 mg / L, a pH between 6-9, a TDS between 1000-2000 mg / L, a calcium ion concentration between 30-70 mg / L, and petroleum hydrocarbons <10 mg / L. The flow rate is 1 m³ / h. 3 / h; the mixed wastewater after mixing of waste alkaline solution and difficult-to-biochemical wastewater has a COD between 560~660mg / L, a pH between 7~8, a TDS between 12000mg / L, and a temperature between 25~28℃. Due to the high salt content, an antagonistic nutrient needs to be added to the regulating water pipeline at a dosage of 1L / h. The effluent from the degassing tank flows by gravity to the aerobic biological reactor. The antagonistic nutrient is potassium ions (K... + The main component is glucose, with small amounts of nitrogen (N), phosphorus (P), and ferric or ferrous ions (Fe). 3+ or Fe2+ ), magnesium (Mg) 2+ The antagonistic nutrient agent comprises ions and an aqueous solution using water as a solvent; preferably, when the antagonistic nutrient agent is added to the mixed wastewater, the dosage of each component satisfies the following:

[0133] The concentration of potassium ions added is 5~10 mg / L;

[0134] The concentration of ferric or ferrous ions added is 1~2 mg / L;

[0135] The concentration of magnesium ions added is 2~3 mg / L;

[0136] The glucose dosage is 20 wt% of the total COD in the mixed wastewater;

[0137] The nitrogen dosage is 2.5 wt% of the total COD in the mixed wastewater;

[0138] The amount of phosphorus added is 0.5 wt% of the total COD in the mixed wastewater.

[0139] The aerobic bioreactor has a specification of φ2.5×10m. By adjusting the aeration rate, the DO value at a depth of 0.3~1.0 meters below the liquid surface of the aerobic bioreactor is controlled between 1.5~4mg / L. The hydraulic retention time is 18h. The effluent from the aerobic bioreactor flows by gravity to the second buffer tank (specification φ1.4×4m).

[0140] The aerobic biochemical reactor was prepared by introducing biochemically activated sludge from the company's wastewater treatment plant 10 days in advance, with a certain amount of glucose and antagonistic nutrients added daily. Initially, 0.1 m³ of sludge was introduced. 3 The amount of waste alkali solution after ozone oxidation is increased appropriately every two days until the expected value of 0.5m³ is reached. 3 After reaching the expected flow rate for 2 days, stop adding glucose, and the sludge cultivation and acclimatization is complete.

[0141] (2b) Deep treatment of waste alkaline solution

[0142] The effluent from buffer tank two is pumped to a candle filter to remove suspended solids (SS) and other particulate pollutants. One candle filter is in operation and one is on standby. Regular backwashing is performed, and the backwash water is discharged back to buffer tank two. Sludge is bagged and transported to the wastewater treatment plant for centralized sludge disposal. The effluent from the candle filter is pressurized to the post-ozone reactor, where ozone is introduced to chemically and strongly oxidize the recalcitrant organic matter in the mixed wastewater. The COD index of the candle filter effluent is shown in Table 6 below.

[0143] Table 6. Data on influent from the biological treatment plant and effluent from the candle filter (unit: mg / L)

[0144]

[0145] The effluent from the post-ozone reactor is degassed and sent to the aerated biological filter, where air is blown in to biochemically degrade the remaining organic matter in the mixed wastewater. The effluent is then sent to the monitoring pool and discharged in compliance with standards.

[0146] The waste gas generated during ozone oxidation and biochemical treatment is then treated in an incinerator.

[0147] The post-ozone reactor, post-deaeration tank, aerated biological filter, and monitoring tank are integrated into a single integrated device, possessing the structure of a single integrated device. Figure 11 This is an elevation view of the integrated equipment 5, which is divided into four chambers from top to bottom: Chamber A (post-ozone reactor), Chamber B (post-degassing tank), Chamber C (aerated biological filter), and Chamber D (monitoring tank). Chamber A (post-ozone reactor) has an exhaust gas outlet 507, a breather valve 508, and a manhole 506 at the top; its side walls have a candle filter inlet 501, an ozone inlet 502, an outlet 503, a manhole 505, a filter media discharge hole 509, a water distribution perforated pipe 510, and an air distribution perforated pipe 511; the bottom is equipped with… There is an exhaust port 504; the filter media 512 is located in the middle of chamber A (post-ozone reactor), the filter media layer height is 2.5~4m, and the bottom of the filter media is more than 1.2m above the bottom of chamber A (post-ozone reactor); the water distribution perforated pipe 510 and the gas distribution perforated pipe 511 are located in the lower part of chamber A (ozone oxidation reactor), and the distance between them is 0.3~0.5m; the side wall of chamber B (post-degassing tank) is provided with an ozone reactor water inlet 513, an outlet 514, an exhaust gas outlet 515, and a manhole 517; bottom The chamber is equipped with an air vent 516; the side wall of chamber C (aerated biological filter) is provided with a rear degassing tank, a water inlet 518, an outlet 519, a compressed air inlet 520, a backwash drain 521, a waste gas outlet 522, a breather valve 523, a dissolved oxygen meter port 524, a manhole 525, 526, a filter media unloading hole 527, a pressure meter port 528, a water distribution perforated pipe 530, and an air distribution perforated pipe 531; an air vent 529 is provided at the bottom; the filter media 532 is located in the middle of chamber C (aerated biological filter). The height of the filter media layer is 2.5~4m, and the distance between the bottom of the filter media and the bottom of the C chamber (aerated biological filter) is greater than 1.2m; the water distribution perforated pipe 530 and the air distribution perforated pipe 531 are located at the bottom of the C chamber (aerated biological filter), and the distance between them is 0.3~0.5m; the side wall of the D chamber (monitoring water tank) is provided with an inlet 533 for the aerated biological filter, an outlet 534, an exhaust gas outlet 536, an upper port 537 for the flange level gauge, a lower port 538 for the flange level gauge, and a manhole 539; the bottom is provided with an exhaust port 535.

[0148] The post-ozone reactor has dimensions of φ1.5×7m, and the ozone dosage is set at 15Nm for a concentration of 100mg / L. 3The ozone aeration is carried out using perforated pipes at a rate of 1000 liters per hour. The hydraulic retention time of the subsequent ozone reactor is 4 hours, and the effluent flows by gravity to the post-deaeration tank.

[0149] The post-deaeration tank has a diameter of φ1.5×2m, and the aerated biological filter has a diameter of φ1.5×7m. The effluent from the post-deaeration tank enters the aerated biological filter, where residual organic matter is biochemically degraded. The aerated biological filter contains volcanic rock filter media. Compressed air is introduced, and after a 2-hour empty bed retention time in the filter media, the effluent is sent to the monitoring tank. The effluent meets discharge standards. The backwash wastewater from the aerated biological filter is periodically sent to buffer tank two.

[0150] The effluent from the biological treatment process was further treated by ozone oxidation and aerated biological filter. The effluent quality data are shown in Table 7 below.

[0151] Table 7. Effluent Water Quality Data (Unit: mg / L)

[0152]

[0153] In this embodiment, the final effluent has a COD of <50mg / L, a petroleum content of <3mg / L, and a pH between 6 and 9.

[0154] (3) Harmless treatment of butter and recycling of quartz sand

[0155] The butter in the butter package and the recycled sand are fed to the sand-oil mixing feeder. The sand is heated and dehydrated in the front section of the sand-oil mixing feeder, and the sand and butter are stirred and mixed in the back section. The weight ratio of sand to butter is 5:1.

[0156] The sand-oil mixing feeder delivers the uniformly mixed and adhered sand and butter mixture to the incinerator, where it undergoes pyrolysis at a temperature between 650 and 800°C. The butter adhering to the surface of the sand is oxidized and decomposed at high temperature. The pyrolyzed sand and ash are then washed and desalted with demineralized water (demineralized water refers to water that has undergone purification treatment, is basically free of calcium and magnesium ions, and has a very low total dissolved solids) by a sand cooling and salt washing conveyor. The sand is then sent back to the sand-oil mixing feeder for recycling. The flue gas generated by incineration and pyrolysis passes through a high-temperature bag filter to intercept the tiny sodium salt and ash particles generated during pyrolysis before entering the secondary combustion chamber for incineration. After recovering heat energy through a waste heat boiler, the flue gas then enters a cooling tower and a spray tower for treatment before being discharged at high altitude after meeting emission standards.

[0157] The grease bag measures 1×1×2.5m and is integrated into the side wall of the grease outlet of the grease remover. The grease separated by the grease remover is temporarily stored in the grease bag and then pumped to the sand-oil mixing feeder. The grease delivery pump has a flow rate of 10kg / h. The grease bag and its inlet and outlet pipelines are lined with polytetrafluoroethylene and electrically heated for insulation, maintaining the temperature of the grease bag and pipelines at 35~40℃.

[0158] The sand-oil mixing feeder adopts a special design structure that integrates the dehydration of recycled sand, mixing with butter, and feeding into the incinerator. First, the sand is indirectly heated by steam generated by a waste heat boiler in the conveying section with a jacket layer to dehydrate it. Second, the dehydrated sand is mixed with butter in proportion in the mixing conveying section. Finally, it is sent to the incinerator feed port.

[0159] Figure 12 This is a schematic diagram of the sand-oil mixing feeder structure in this invention. The sand-oil mixing feeder has the structure of a sand-oil mixing feeder 6, specifically including a mixing feeder auger end shaft 601, a bearing cover 602, a bracket 603, an oil seal cover 604, a seat cover 605, a copper sleeve 606, an auger shell end flange 607, a mixed sand inlet 608, an auger shell 609, blades 610, an auger shaft 611, a grease inlet inspection box 612, a gravity sealing cover 613, a grease inlet 614, a grease and mixed sand mixture outlet 615, a rear end cover 616, a second oil seal cover 617, a steam jacket 618, a steam inlet 619, a condensate outlet 620, and a vapor phase outlet 621. The sand-oil mixing feeder has a specification of DN50×6m. 60kg / h of cooled and washed quartz sand is dried by steam from a waste heat boiler at the front of the sand-oil mixing feeder, and then mixed with grease at the rear. The mixture then enters the pyrolysis incinerator (rotary kiln). The sand-oil mixing feeder and its inlet and outlet pipelines are electrically heated and insulated. The grease package is heated at a temperature of 35~38℃, and the grease conveying pipeline is heated at a temperature of 40~45℃.

[0160] The total flow rate of the pyrolysis incinerator's mixture of grease and quartz sand is approximately 70 kg / h. Fuel gas and hot air are introduced into the rotary kiln of the pyrolysis incinerator; the rotary kiln has dimensions of φ0.8 × 7 m. The rotary kiln temperature is controlled at 750℃, with an oxygen content of 6 vol%-10 vol%. A high-temperature metal fiber filter bag dust collector is installed between the rotary kiln and the secondary combustion chamber to trap any ash that may enter the secondary combustion chamber. The temperature of the secondary combustion chamber is controlled at approximately 1100℃. The exhaust gas passes through a waste heat boiler, a scrubbing tower, and an induced draft fan before being discharged in compliance with standards. A portion of the steam generated by the waste heat boiler is used to dry the quartz sand before the sand-oil mixing feeder, with the remainder discharged to the main steam pipe.

[0161] Add 1m to the sand cooling and washing salt conveyor 3 The demineralized water is processed at a rate of / h to wash the quartz sand. The cooled wash water is discharged into buffer tank 1, and the COD value of the cooled wash water is ≤10mg / L. The quartz sand is then conveyed to the sand-oil mixing feeder for recycling. Quartz sand experiences some wear, so it is periodically replenished with quartz sand of 0.2~1.5mm particle size every 10 days, with each replenishment amounting to 20~50kg.

[0162] The sand cooling and washing conveyor adopts a special design structure that integrates the cooling, washing and conveying of recycled sand into one unit. First, in the horizontal conveying section, washing brine enters from one side and overflows from the other side to cool and wash the sand. Second, the recycled sand is sent to the reuse point through the buried scraper at the rear. Figure 13 This is a schematic diagram of the sand cooling and salt washing conveyor structure of the present invention. The sand cooling and salt washing conveyor has the structure of a sand cooling and salt washing conveyor 7, specifically including a sand washing water outlet 701, a water tank 702, an overflow baffle 703, a tail section 704, a driven wheel 705, a tail inspection port 706, a feeding section 707, an inlet for recycled sand from the incinerator 708, a sand washing water inlet 709, a lower curved section 710, a lower curved section inspection port 711, a lower curved section back inspection port 712, a vertical section 713, an upper curved section 714, an upper curved section inspection port 715, a head section 716, a head inspection port 717, a cooled and desalinated recycled sand outlet 718, and a driving wheel 719.

[0163] The pyrolysis section and the secondary combustion chamber section of the incinerator are equipped with high-temperature bag filters to intercept tiny sodium salt particles and fly ash generated during pyrolysis. The flue gas from the secondary combustion chamber first passes through a waste heat boiler to recover heat energy for dehydration and heating of the accompanying sand. After being treated by a cooling tower and a spray tower, it meets the standards and is discharged into the atmosphere through a chimney. The high-temperature bag filter is a high-temperature metal fiber bag filter with a temperature resistance of not less than 750℃.

[0164] The pilot plant performed grease removal, grease harmless treatment, and standard-compliant treatment on coal-to-olefins waste alkaline liquor, proving the feasibility of the waste alkaline liquor treatment method. After two months of continuous and stable operation of the pilot plant, the equipment and pipelines were inspected. The grease inlet and outlet pipelines were found to be unblocked, the rotary kiln and secondary combustion chamber were free of scaling and blockage, the quartz sand was recycled, and the grease was rendered harmless.

[0165] As can be seen from the embodiments, the method for treating coal-to-olefins waste alkaline solution of the present invention is feasible.

[0166] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that, based on the technical solutions of the present invention, various modifications or variations of equivalent structures or equivalent processes that can be made by those skilled in the art without creative effort, or directly or indirectly applied to other related technical fields, are still within the scope of protection of the present invention.

Claims

1. A method for treating waste alkaline solution from a coal-to-olefins plant to meet standards, characterized in that, This includes the following steps performed sequentially: (1) Removal of butter from waste alkali solution Waste alkaline liquid from the coal-to-olefins unit is transported to a grease remover. The density difference between the grease and the waste alkaline liquid causes them to separate into layers. The upper part of the grease remover contains grease, and the lower part contains the grease-removed waste alkaline liquid. The separated grease flows by gravity to a grease bag for collection, while the grease-removed waste alkaline liquid is sent to a buffer tank through a drainage level regulator. The inner walls of the grease bag and the grease conveying pipeline are lined with an oleophobic material. At the same time, the grease remover, grease bag, and grease conveying pipeline are equipped with heat tracing. (2) Treatment of waste alkali solution for removing butter (2a) Pretreatment of waste alkaline solution The waste alkaline solution obtained after step (1) is treated with 1 to 1.5 times the weight of the waste alkaline solution and diluted with cooling brine containing sand. The mixture is then mixed in a buffer tank and cooled before being sent to an ozone oxidation reactor. Ozone is introduced to break down the chains of the organic matter in the waste alkaline solution that is difficult to biodegrade and to oxidize it with ozone, thereby improving the biodegradability of the waste alkaline solution. The effluent from the ozone oxidation reactor is neutralized with acidic substances and sent to a degassing tank for degassing. The cooling brine containing sand is the water used in step (3) for cooling and washing the sand from the incinerator, wherein the sodium carbonate content is less than 1% and the chemical oxygen demand (COD) is less than 10 mg / L. The effluent from the degassing tank is mixed with the conditioning water and then enters the biochemical reactor. The total dissolved solids (TDS) of the mixed wastewater is controlled at 12,000~18,000 mg / L. At the same time, antagonistic nutrients are added in proportion, air is blown in, and biochemical treatment is carried out. Organic pollutants in the mixed wastewater are removed by aerobic microorganisms, and the treated effluent is discharged to buffer tank two. (2b) Deep treatment of waste alkaline solution The mixed wastewater treated in step (2a) is sent to a filter to remove particulate pollutants such as suspended solids (SS). The mixed wastewater then enters a post-ozone reactor where ozone is introduced to chemically oxidize the organic matter in the mixed wastewater that is difficult to biodegrade. The effluent from the post-ozone reactor is degassed and sent to the aerated biological filter, where air is blown in to biochemically degrade the remaining organic matter in the mixed wastewater. The effluent is then sent to the monitoring pool and discharged in compliance with standards. The waste gas generated during ozone oxidation and biochemical treatment is then treated in an incinerator. (3) Harmless treatment of butter and recycling of accompanying sand The butter in the butter package and the recycled sand are fed to the sand-oil mixing feeder. The sand is heated and dehydrated in the front section of the sand-oil mixing feeder, and the sand and butter are stirred and mixed in the back section. The weight ratio of sand to butter is 5:1 to 12:

1. The sand-oil mixing feeder delivers the uniformly mixed and adhered sand and butter mixture to the incinerator, where it undergoes pyrolysis at a temperature between 650 and 800°C. The butter adhering to the surface of the sand is oxidized and decomposed at high temperature. The pyrolyzed sand and ash are then washed and desalted with demineralized water by a sand cooling and washing conveyor before being sent back to the sand-oil mixing feeder for recycling. The flue gas generated during incineration and pyrolysis passes through a high-temperature bag filter to intercept the tiny sodium salt and ash particles produced during pyrolysis before entering the secondary combustion chamber for incineration. After recovering heat energy through a waste heat boiler, the flue gas is then treated in sequence in a cooling tower and a spray tower before being discharged at high altitude after meeting emission standards.

2. The method according to claim 1, characterized in that, The waste alkaline solution from the coal-to-olefins unit mentioned in step (1) refers to a waste alkaline solution with sodium hydroxide (NaOH) between 1 and 2 wt%, sodium carbonate (Na2CO3) between 1.5 and 4 wt%, butter between 2500 and 6000 mg / L, COD between 8000 and 20000 mg / L, TDS between 40000 and 80000 mg / L, and pH between 13 and 14.

3. The method according to claim 1, characterized in that, In step (1), the effective liquid level of the grease remover is not less than 5m; the surface hydraulic load is 0.03~0.1m. 3 / (m 2 •h); The grease package is integrated on the side wall of the grease remover and shares a grease inlet with the grease remover, avoiding long-distance transport; Preferably, the hydraulic load on the surface of the grease remover is 0.05~0.06m. 3 / (m 2 ·h); The degreaser includes a waste alkali inlet, a waste alkali outlet, a grease outlet, vent a, vent b, a utility port, a temperature instrument port, a flange level gauge lower port, a flange level gauge upper port, a pressure instrument port, a breather valve port, a nitrogen seal port, an emergency vent, a waste gas outlet, an upper maintenance manhole, a lower maintenance manhole, an oil-water manifold, a water distribution ring pipe, a water collection ring pipe, an inlet connecting pipe, an outlet connecting pipe, a siphon breaking pipe, and sight glasses a, b, and c. The components include: a mirror (d), a drain level regulator, and a grease bag; the structure of the oil-water manifold in the grease remover includes an inlet, a water distribution ring pipe interface, a water collection ring pipe interface, an outlet, an inner cavity, and an annular jacket cavity; the structure of the drain level regulator includes a handwheel, a nut bracket, a lead screw, an O-ring, a siphon breaking interface, an inlet, an adjustable sleeve, and an outlet; the structure of the grease bag includes a manhole with a sight glass, a temperature instrument port, a grease drain port, a level instrument port, and a grease inlet port; The diameter of the grease remover is D; the oil-water manifold is located in the center of the grease remover; the vertical height of the water distribution ring pipe from the bottom of the grease remover is H1, where H1 is 2.5~3m, and the water distribution ring pipe has evenly distributed upward-facing water distribution holes. The water distribution ring pipe is connected to the water distribution ring pipe interface of the oil-water manifold through three interconnecting pipes at 120° intervals. The water distribution ring pipe interface is connected to the liquid inlet of the grease remover through an annular jacket cavity. The liquid inlet of the grease remover is connected to the waste alkali liquid inlet through a water inlet connecting pipe; the water collection ring pipe is located at the bottom of the grease remover, with a vertical height of H2 from the bottom of the grease remover, where H2 is 0.4~0.8m, and the water collection ring pipe has evenly distributed downward-facing water collection holes. The water collection ring pipe is connected to the oil-water manifold through three interconnecting pipes at 120° intervals. The water collection ring pipe interface is connected, and the water collection ring pipe interface is connected to the outlet of the degreaser through the inner cavity. The outlet of the degreaser is connected to the outlet of the degreased waste alkali liquid through the water outlet connecting pipe. One end of the siphon breaking pipe is connected to the siphon breaking interface of the drainage level regulator, and the other end is connected to the gas phase space inside the degreaser to maintain the pressure balance between the degreased waste alkali liquid surface and the grease liquid surface. The grease outlet and the grease inlet of the grease bag are the same. The vertical distance between the lower edge of the grease outlet and the center of the water inlet of the adjustable sleeve in the drainage level regulator is Δh, which can be adjusted between 0.05 and 0.20 m. The vertical distance between the lower edge of the grease outlet and the oil-water interface is the oil layer thickness H, where H = ρ × Δh / Δρ; where ρ is the density of the waste alkali liquid, in kg / m³. 3 Δh is the difference between the lower edge elevation of the butter outlet and the center elevation of the adjustable sleeve inlet, in meters (m); Δρ is the density difference between the waste alkali solution and the butter, in kilograms per cubic meter of water. 3 The sight glasses a-d are evenly distributed on the side wall of the grease remover, at a height of H along the oil layer thickness. The inlet of the drain level regulator is connected to the outlet of the grease remover's waste alkali solution. By adjusting the height of the adjustable sleeve, Δh is adjusted to control the oil layer thickness H. The grease pack is located on the side wall of the grease remover, sharing the same wall with it. The top of the grease remover is equipped with a pressure gauge port, a breather valve port, a nitrogen seal port, an emergency release port, a waste gas outlet, and an upper maintenance manhole. The side wall is equipped with a lower flange port for the level gauge, an upper flange port for the level gauge, a temperature instrument port, sight glasses a-d, and a lower maintenance manhole. The bottom is equipped with an vent.

4. The method according to claim 1, characterized in that, In step (1), the inner wall of the butter package and the inner wall of the butter delivery pipe are lined with an oleophobic material to reduce butter adhesion. The lining material is polytetrafluoroethylene (PTFE), silicone, fluorinated ethylene propylene copolymer (FEP), or perfluoroalkoxy resin (PFA). Preferably, the oleophobic liner is polytetrafluoroethylene (PTFE).

5. The method according to claim 1, characterized in that, In step (1), the grease remover, grease bag and grease delivery pipeline are heated by steam heating, hot water heating or electric heating to maintain the internal temperature between 30 and 50°C. Preferably, the grease remover, grease bag, and grease delivery pipeline are heated by electric heating; the temperature inside the grease remover and grease bag is maintained between 35 and 38°C; and the temperature inside the grease delivery pipeline is maintained between 40 and 45°C.

6. The method according to claim 1, characterized in that, In step (2a), the buffer tank one, buffer tank two, cooler, and ozone oxidation reactor are integrated devices. Preferably, the integrated equipment is structured from top to bottom as follows: chamber A, chamber B, and chamber C. Chamber A is an ozone oxidation reactor, chamber B is a second buffer tank, and chamber C is a first buffer tank. Chamber A includes an inlet, an ozone inlet, an outlet, an air outlet, a bottom manhole, a top manhole, a waste gas outlet, a breather valve, a filter media unloading hole, a water distribution perforated pipe, a gas distribution perforated pipe, and filter media. Chamber B includes a biochemical water inlet, a backwash drainage inlet, an outlet, an air outlet, a waste gas outlet, an upper flange level gauge, a lower flange level gauge, and a manhole. Chamber C includes a grease-removing waste alkali inlet, a mixed sand cooling brine inlet, an outlet, an air outlet, a waste gas outlet, an upper flange level gauge, a lower flange level gauge, a temperature instrument port, a cooling water inlet, a cooling water outlet, a manhole, and a cooler. The integrated device has a diameter of D, with an upper section (cavity A), a middle section (cavity B), and a lower section (cavity C). Cavity A has a top manhole, an exhaust outlet, and a breather valve at the top; its side walls have a water inlet, an ozone inlet, a water outlet, an air outlet, a bottom manhole, a filter media unloading hole, a water distribution perforated pipe, and an air distribution perforated pipe. The filter media is located in the middle of cavity A, with a layer height of 2.5~4m, and the bottom of the filter media is more than 1.2m above the bottom of cavity A. The water distribution perforated pipe and the air distribution perforated pipe are located at the bottom of cavity A, with a distance of 0.3~0m between them. 0.5m; the side wall of cavity B is provided with a biochemical water inlet, a backwash drainage inlet, a water outlet, a waste gas outlet, an upper flange level gauge inlet, a lower flange level gauge inlet, and a manhole; a vent is provided at the bottom; the side wall of cavity C is provided with a waste alkali solution inlet for removing grease, a demineralized water inlet for the accompanying sand, a water outlet, a waste gas outlet, an upper flange level gauge inlet, a lower flange level gauge inlet, a temperature instrument port, a cooling water inlet, a cooling water outlet, and a manhole; a vent is provided at the bottom; the cooler is located at the lower part of cavity C and is connected to the cooling water inlet and cooling water outlet.

7. The method according to claim 1, characterized in that, In step (2a), an acidic substance is added to neutralize the pH value. The acidic substance is sulfuric acid, hydrochloric acid, or sodium bisulfate. Preferably, the acidic substance used to adjust the pH of the neutralized waste alkaline solution is sulfuric acid.

8. The method according to claim 1, characterized in that, In step (2a), the degassing tank and the biochemical reactor are integrated devices. The structure of the integrated equipment is divided into chamber A and chamber B from top to bottom. Chamber A is a degassing tank and chamber B is a biochemical reactor. Chamber A includes an ozone oxidation reactor water inlet, regulating water inlet, vent, outlet, exhaust gas outlet, and manhole. Chamber B includes a degassing tank water inlet, compressed air inlet, vent a, vent b, outlet, exhaust gas outlet, breather valve, dissolved oxygen meter port, manhole a, manhole b, floating plate packing, main gas distribution pipe, and branch gas distribution pipe. The integrated device has a diameter of D, with the upper section being cavity A and the lower section being cavity B. Cavity A (degassing tank) has a waste gas outlet and a manhole at the top; the side wall has an ozone oxidation reactor inlet, a regulating water inlet, an air outlet, and a water outlet. Cavity B (biochemical reactor) has an inlet, a compressed air inlet, a water outlet, a waste gas outlet, a breather valve, a dissolved oxygen meter port, and a manhole on its side wall; the bottom has an air outlet. The floating disc packing is located in the middle of cavity B, with a packing density of 90~95v%. The main gas distribution pipe and branch gas distribution pipe are located in the lower part of cavity B, with the main gas distribution pipe 0.15~0.3m from the bottom of cavity B. The branch gas distribution pipe is connected to the main gas distribution pipe, and aeration holes at a 45° downward angle are evenly distributed on the branch gas distribution pipe.

9. The method according to claim 1, characterized in that, In step (2a), the antagonistic nutrient is potassium ions (K ions). + The main component is glucose, with small amounts of nitrogen (N), phosphorus (P), and ferric or ferrous ions (Fe). 3+ or Fe 2+ ), magnesium (Mg) 2+ The antagonistic nutrient agent comprises ions and an aqueous solution using water as a solvent; preferably, when the antagonistic nutrient agent is added to the mixed wastewater, the dosage of each component satisfies the following: The concentration of potassium ions added is 5~10 mg / L; The concentration of ferric or ferrous ions added is 1~2 mg / L; The concentration of magnesium ions added is 2~3 mg / L; The glucose dosage is 20 wt% of the total COD in the mixed wastewater; The nitrogen dosage is 2.5 wt% of the total COD in the mixed wastewater; The amount of phosphorus added is 0.5 wt% of the total COD in the mixed wastewater.

10. The method according to claim 1, characterized in that, In step (2b), the post-ozone reactor, post-degassing tank, aerated biological filter and monitoring pool are integrated devices. The integrated equipment is structured from top to bottom as follows: Chamber A, Chamber B, Chamber C, and Chamber D. Chamber A is the post-ozone reactor, including a filter inlet, ozone inlet, outlet, vent, bottom manhole, top manhole, exhaust gas outlet, breather valve, filter media unloading hole, water distribution perforated pipe, air distribution perforated pipe, and filter media. Chamber B is the post-degassing tank, including a post-ozone reactor inlet, outlet, exhaust gas outlet, vent, and manhole. Chamber C is the aerated biological filter, including a post-degassing tank inlet, outlet, compressed air inlet, backwash drain, exhaust gas outlet, breather valve, dissolved oxygen meter port, manhole a, manhole b, filter media unloading hole, pressure meter port, vent, water distribution perforated pipe, air distribution perforated pipe, and filter media. Chamber D is the monitoring tank, including an aerated biological filter inlet, outlet, vent, exhaust gas outlet, upper flange level gauge port, lower flange level gauge port, and manhole. The integrated device has a diameter of D, with the upper section being cavity A, the middle sections being cavities B and C, and the lower section being cavity D. Cavity A has an exhaust gas outlet, a breather valve, and a manhole at the top; its side walls have a candle filter inlet, an ozone inlet, an outlet, a manhole, a filter media discharge port, a water distribution perforated pipe, and a gas distribution perforated pipe; and a vent at the bottom. The filter media is located in the middle of cavity A, with a filter media layer height of 2.5~4m, and the bottom of the filter media is more than 1.2m above the bottom of cavity A. The water distribution perforated pipe and the gas distribution perforated pipe are located at the lower part of cavity A, with a distance of 0.3~0.5m between them. Cavity B has an ozone reactor inlet, an outlet, an exhaust gas outlet, and a manhole on its side walls; and a vent at the bottom. The C chamber has the following features: a rear degassing tank inlet, outlet, compressed air inlet, backwash drain outlet, exhaust gas outlet, breather valve outlet, dissolved oxygen meter outlet, manhole, filter media unloading hole, pressure meter outlet, water distribution perforated pipe, and air distribution perforated pipe; an exhaust port is located at the bottom; the filter media is located in the middle of the C chamber, with a filter media layer height of 2.5~4m and a bottom height of more than 1.2m from the bottom of the C chamber; the water distribution perforated pipe and air distribution perforated pipe are located at the bottom of the C chamber, with a distance of 0.3~0.5m between them; the D chamber has the aerated biological filter inlet, outlet, exhaust gas outlet, upper flange level gauge outlet, lower flange level gauge outlet, and manhole on its side wall; an exhaust port is located at the bottom.

11. The method according to claim 1, characterized in that, In step (3), the pyrolysis time of the incinerator is 1 to 2 hours; the pyrolysis temperature is 650 to 800°C. Preferably, the pyrolysis temperature of the incinerator is 680~750℃.

12. The method according to claim 1, characterized in that, In step (3), the accompanying sand can be quartz sand, river sand, ceramic sand or metal sand; the particle size is between 0.1 and 5 mm; the Mohs hardness is not less than 5; and the melting point is not less than 900℃. Preferably, the particle size of the accompanying sand is between 0.2 and 1.5 mm; the Mohs hardness is not less than 6; and the melting point is not less than 1200°C. Preferably, the accompanying sand is quartz sand.

13. The method according to claim 1, characterized in that, In step (3), the sand-oil mixing feeder integrates the dehydration of recycled sand, mixing with butter, and feeding into the incinerator; firstly, the sand is dehydrated by indirect heating with steam generated by a waste heat boiler in the conveying section with a jacket layer; Secondly, the dehydrated sand and butter are mixed in proportion through a mixing conveyor section; finally, the mixture is sent to the incinerator feed inlet. Preferably, the sand-oil mixing feeder has a structure including a mixing feeder auger end shaft, bearing cover, bracket, oil seal cover, seat cover, copper sleeve, auger shell end flange, sand inlet, auger shell, blades, auger shaft, grease inlet inspection box, gravity seal cover, grease inlet, grease and sand mixture outlet, rear end cover, oil seal cover II, steam jacket, steam inlet, condensate outlet, and vapor phase outlet.

14. The method according to claim 1, characterized in that, In step (3), the sand cooling and washing conveyor integrates the cooling, washing and conveying of the recycled sand. First, in the horizontal conveying section, washing water enters on one side and overflows on the other side to cool and wash the sand. Second, the recycled sand is sent to the sand-oil mixing feeder for reuse through the rear scraper. Preferably, the sand cooling and salt washing conveyor has a structure including a sand washing water outlet, a water tank, an overflow baffle, a tail section, a driven wheel, a tail inspection port, a feeding section, an inlet for recycled sand from the incinerator, a sand washing water inlet, a lower curved section, an inspection port for the lower curved section, an inspection port at the back of the lower curved section, a vertical section, an upper curved section, an inspection port for the upper curved section, a head section, a head inspection port, an outlet for the cooled and desalinated recycled sand, and a driving wheel.

15. The method according to claim 1, characterized in that, In step (3), high-temperature bag filters are installed in the pyrolysis section and the secondary combustion chamber section of the incinerator to intercept tiny sodium salt particles and fly ash generated during the pyrolysis process; the flue gas from the secondary combustion chamber first passes through the waste heat boiler to recover heat energy for dehydration and heating of the accompanying sand; after being treated by the cooling tower and spray tower, it meets the standards and is discharged into the air through the chimney. Preferably, the high-temperature bag filter is a high-temperature metal fiber bag filter with a temperature resistance of not less than 750℃.

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