A shale dry distillation wastewater resourceful treatment and recycling system and process

Abstract

A shale dry distillation wastewater resource treatment and recycling system and process, in which a first condenser condenses and liquefies ammonia steam discharged from a stripping ammonia distillation tower, and a second condenser condenses and liquefies ammonia steam discharged from the stripping ammonia distillation tower; an ammonia water recovery tank is used to store ammonia water generated by condensation and liquefaction; the ammonia water recovery tank is connected to a lower section of an oxidation circulator through a pipeline, one side of the lower section of the oxidation circulator is connected to an oxygen input pipeline, the other side of the lower section of the oxidation circulator is connected to an oxygen output pipeline connected to a middle section of a desulfurization tower; an ammonia liquid input pipeline is connected between the lower section of the oxidation circulator and the middle section of the desulfurization tower; a lower section of the desulfurization tower is connected to a boiler flue gas input pipeline and an ammonium sulfate output pipeline, and the desulfurization tower is used to desulfurize boiler flue gas by using ammonia water and oxygen delivered by the oxidation circulator. The present application reduces the consumption of steam and alkali liquor, efficiently utilizes ammonia resources, and greatly reduces energy consumption.

Description

Technical Field

[0001] This invention relates to a system and process for the resource-based treatment and reuse of shale dry distillation wastewater, belonging to the field of industrial wastewater treatment technology. Background Technology

[0002] Oil shale is a sedimentary rock that, when heated to around 500℃, yields shale oil. Shale oil is similar to petroleum but not identical. The production, processing, and use of shale oil generate large amounts of shale distillation wastewater. In recent years, the environmental problems caused by shale distillation wastewater from chemical plants have become increasingly serious, particularly in industrial production processes such as tire manufacturing, chemical production, and fine chemicals, all of which generate significant quantities of shale distillation wastewater.

[0003] Shale carbonization wastewater contains a wide variety of pollutants, with complex compositions and high concentrations, including high levels of ammonia nitrogen and organic pollutants. It is recognized globally as a difficult-to-treat wastewater and is one of the key industries for which China has introduced advanced treatment technologies. The large quantities of high-concentration ammonia nitrogen wastewater generated during shale carbonization, when discharged into rivers and lakes, can cause eutrophication, disrupting the balance of aquatic ecosystems and consequently impacting human health and the living environment. Furthermore, the large amount of ammonia nitrogen in the wastewater cannot be recovered and reused, resulting in significant resource waste.

[0004] Currently, it is difficult to directly use ordinary biological treatment for shale carbonization wastewater containing high concentrations of ammonia nitrogen. Due to the extremely high ammonia nitrogen concentration, most of the ammonia nitrogen pollutants must be removed from the wastewater before it enters the biological treatment process. At present, the main methods for treating high concentrations of ammonia nitrogen include stripping, magnesium ammonium phosphate, and ammonia stripping.

[0005] The stripping method mainly relies on air to strip ammonia nitrogen from wastewater in the form of ammonia molecules. The process mainly consumes electrical energy from pumps and blowers. The ammonia molecules treated by this method are discharged into the atmosphere with the air and cannot be recovered. It is suitable for situations where the ammonia nitrogen concentration is not too high and the requirements for the treated effluent are not too high.

[0006] The magnesium ammonium phosphate method mainly involves adding reagents to cause a precipitation reaction between the reagents and ammonia nitrogen in the wastewater. It is suitable for treating wastewater with relatively low ammonia nitrogen concentrations. However, precipitation will occur during the process. If the wastewater contains pollutants such as heavy metals, it can easily become hazardous waste, thus causing secondary pollution.

[0007] Ammonia stripping primarily relies on external steam as a heat source, resulting in low energy consumption and suitability for treating wastewater with high ammonia nitrogen concentrations. It can recover relatively high concentrations of ammonia water, demonstrating promising application prospects. However, in actual operation, high ammonia concentrations often occur in the bottom of the stripping tower, affecting the efficiency of the system and making recovery difficult. Furthermore, ammonia water recovered using conventional stripping techniques is prone to loss and develops a foul odor during recovery and transportation. Summary of the Invention

[0008] The purpose of this invention is to provide a system and process for the resource-based treatment and reuse of shale carbonization wastewater, which solves the problems of difficulty in resource-based reuse, high recycling difficulty, and easy pollution caused by traditional shale carbonization wastewater treatment.

[0009] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: a shale dry distillation wastewater resource treatment and reuse system, including a raw water storage tank, a reboiler, an alkali storage tank, a stripping ammonia stripping tower, a primary condenser, a secondary condenser, a recovered ammonia water storage tank, an oxidation circulator and a desulfurization tower;

[0010] The raw water storage tank is connected to the middle section of the stripping ammonia tower via a pipeline. The raw water storage tank is used to transport shale dry distillation wastewater to the stripping ammonia tower.

[0011] The reboiler is connected to the middle section of the stripping ammonia tower via a pipeline, and the reboiler is used to deliver steam to the stripping ammonia tower.

[0012] The alkali storage tank is connected to the middle section of the stripping ammonia tower via a pipeline. The alkali storage tank is used to mix the shale dry distillation wastewater and alkali solution transported to the stripping ammonia tower.

[0013] The pipeline at the top of the ammonia stripping tower is divided into two branches, connecting to the primary condenser and the secondary condenser. The primary condenser is connected to the secondary condenser via a pipeline, and the secondary condenser is connected to the recovered ammonia water storage tank via a pipeline. The primary condenser is used for primary condensation and liquefaction of the ammonia vapor discharged from the ammonia stripping tower, and the secondary condenser is used for secondary condensation and liquefaction of the ammonia vapor discharged from the ammonia stripping tower. The recovered ammonia water storage tank is used to store the ammonia water produced by condensation and liquefaction.

[0014] The ammonia recovery storage tank is connected to the lower section of the oxidation circulator via a pipeline. One side of the lower section of the oxidation circulator is connected to an oxygen input pipeline, and the other side of the lower section of the oxidation circulator is connected to an oxygen output pipeline that connects to the middle section of the desulfurization tower. An ammonia input pipeline is connected between the lower section of the oxidation circulator and the middle section of the desulfurization tower. The lower section of the desulfurization tower is connected to a boiler flue gas input pipeline and an ammonium sulfate output pipeline. The desulfurization tower is used to desulfurize the boiler flue gas using the ammonia and oxygen supplied by the oxidation circulator.

[0015] As a preferred embodiment of the shale carbonization wastewater resource treatment and reuse system, the upper end of the raw water storage tank is connected to a shale carbonization wastewater input pipeline, which is used to transport the shale carbonization wastewater to the raw water storage tank.

[0016] As a preferred embodiment of the shale carbonization wastewater resource treatment and reuse system, the bottom of the reboiler is connected to a steam input pipeline, and a steam pump is installed on the steam input pipeline; the steam input pipeline delivers steam to the reboiler through the steam pump.

[0017] As a preferred embodiment of the shale dry distillation wastewater resource treatment and reuse system, the alkali storage tank is connected to an alkali input pipeline, which is used to transport NaOH alkali solution to the alkali storage tank.

[0018] As a preferred scheme for the resource-based treatment and reuse system of shale dry distillation wastewater, a dilute ammonia water circulation pipeline is connected between the middle section of the primary condenser and the stripping ammonia tower. The dilute ammonia water circulation pipeline is equipped with a dilute ammonia water circulation pump. The dilute ammonia water liquefied in the primary condenser is returned to the stripping ammonia tower for concentration and purification through the dilute ammonia water circulation pump.

[0019] As a preferred scheme for the resource-based treatment and reuse system of shale dry distillation wastewater, a water washing circulation input pipeline is connected between one side of the upper section of the oxidation circulator and the upper section of the desulfurization tower, and a water washing circulation pump is installed on the water washing circulation input pipeline. A water washing circulation output pipeline is connected between the other side of the upper section of the oxidation circulator and the water washing section of the desulfurization tower.

[0020] As a preferred solution for the resource-based treatment and reuse system of shale dry distillation wastewater, an ammonia pump is installed on the ammonia inlet pipeline, and the ammonia inlet pipeline delivers ammonia water to the desulfurization tower through the ammonia pump.

[0021] As a preferred solution for the resource-based treatment and reuse system of shale dry distillation wastewater, an ammonium sulfate circulation pipeline is connected to one side of the lower section of the desulfurization tower, and an ammonium sulfate circulation pump is installed on the ammonium sulfate circulation pipeline; an ammonium sulfate discharge pump is installed on the ammonium sulfate output pipeline.

[0022] The upper section of the desulfurization tower is connected to a water washing pipeline, and an inlet pump is installed on the water washing pipeline; the water washing pipeline uses the inlet pump to wash and cool the purified flue gas.

[0023] The top of the desulfurization tower is connected to a chimney, which is used to discharge the purified flue gas.

[0024] This invention also provides a process for the resource-based treatment and reuse of shale carbonization wastewater, which employs the above-mentioned shale carbonization wastewater resource-based treatment and reuse system and includes the following steps:

[0025] The pre-treated shale distillation wastewater enters the raw water storage tank. After being pressurized in the raw water storage tank, it enters the middle section of the stripping ammonia stripping tower. The alkali solution is released after entering the alkali solution storage tank and is mixed with the shale distillation wastewater before entering the middle section of the stripping ammonia stripping tower.

[0026] After being pressurized by external steam, it enters the reboiler for heating and then enters the middle section of the ammonia stripping tower, where steam, shale dry distillation wastewater, and alkaline solution are mixed for stripping.

[0027] The ammonia vapor obtained from the stripping of ammonia is discharged from the top of the stripping ammonia tower and then enters the first-stage condenser. Part of the ammonia vapor is liquefied into dilute ammonia water by the first-stage condenser and flows back to the middle section of the stripping ammonia tower for further concentration and purification. The remaining ammonia vapor and the concentrated and purified ammonia vapor enter the second-stage condenser to liquefy produce ammonia water. The produced ammonia water enters the ammonia water recovery storage tank and is used as a raw material for desulfurization.

[0028] Ammonia water is pressurized in the ammonia water recovery storage tank and enters the lower oxidation section of the oxidation cycler. On the other side of the lower oxidation cycler, the ammonia water is pressurized and pumped into the middle spray desulfurization section of the desulfurization tower to absorb and desulfurize the boiler flue gas. After the boiler flue gas is absorbed by ammonia water, an ammonium sulfite solution is generated. Oxygen is blown into the lower concentration section of the desulfurization tower through the oxidation cycler to oxidize the ammonium sulfite solution formed in the spray desulfurization section, and after oxidation, an ammonium sulfate solution is generated.

[0029] Boiler flue gas enters the concentration section from the bottom of the desulfurization tower. In the desulfurization section, it is absorbed and reacted with countercurrent ammonia water. The remaining unreacted flue gas continues to enter the upper water washing section of the desulfurization tower. The upper water washing section performs water washing and cooling operations on the purified flue gas.

[0030] After being washed, the washing liquid flows back into the upper section of the oxidation circulator. The upper section of the oxidation circulator pumps the circulating water into the washing section of the desulfurization tower to form a washing cycle. The purified flue gas after being washed is discharged from the flue gas outlet at the top of the desulfurization tower and then discharged into the chimney.

[0031] The resulting dilute ammonium sulfate solution is pressurized and circulated back to the upper part of the concentration section from the bottom of the desulfurization tower to wash and concentrate the flue gas. The high-concentration ammonium sulfate solution is discharged from the bottom of the desulfurization tower and then utilized as a resource.

[0032] As a preferred process for the resource-based treatment and reuse of shale dry distillation wastewater, the operating pressure of the stripping ammonia stripping tower is 0.3 MPa, the operating temperature at the top of the stripping ammonia stripping tower is <93℃, the operating temperature at the bottom of the stripping ammonia stripping tower is <104℃, and the pH of the mixed liquid is 10-11.

[0033] This invention boasts advantages such as high resource utilization performance, low energy consumption, no environmental pollution, and good stability, meeting the requirements of green chemical production. It reduces the consumption of steam and alkali solution, efficiently utilizes ammonia resources, significantly lowers energy consumption, and substantially reduces equipment investment. This invention improves ammonia water quality, reduces the cost of ammonia stripping treatment in shale distillation wastewater, and lowers the cost of flue gas desulfurization raw materials, turning waste into treasure. It enables low-carbon, environmentally friendly, efficient, and low-cost resource utilization of ammonia stripping from shale distillation wastewater. This invention belongs to a new type of clean technology for the circular economy, possessing advantages such as high desulfurization efficiency, no secondary pollution, resource recovery of sulfur dioxide, and economical solution to ammonia loss. The produced ammonium sulfate solution can also be used for soil improvement, meeting the requirements of the circular economy, further achieving resource utilization and environmental protection requirements. Attached Figure Description

[0034] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0035] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0036] Figure 1 This is a schematic diagram of a shale dry distillation wastewater resource treatment and reuse system provided in an embodiment of the present invention;

[0037] Figure 2 This is a schematic diagram of the shale dry distillation wastewater resource utilization process provided in an embodiment of the present invention.

[0038] In the diagram, 1. Raw water storage tank; 2. Reboiler; 3. Alkali storage tank; 4. Ammonia stripping tower; 5. Primary condenser; 6. Secondary condenser; 7. Ammonia recovery storage tank; 8. Oxidation circulator; 9. Desulfurization tower; 10. Oxygen input pipeline; 11. Oxygen output pipeline; 12. Ammonia input pipeline; 13. Boiler flue gas input pipeline; 14. Ammonium sulfate output pipeline; 15. Shale distillation wastewater input pipeline; 16. Steam input pipeline; 17. Steam pump; 18. Alkali input pipeline; 19. Dilute ammonia circulation pipeline; 20. Dilute ammonia circulation pump; 21. Washing water circulation input pipeline; 22. Washing water circulation pump; 23. Washing water circulation output pipeline; 24. Ammonia pump; 25. Ammonium sulfate circulation pipeline; 26. Ammonium sulfate circulation pump; 27. Ammonium sulfate discharge pump; 28. Washing water supply pipeline; 29. ​​Inlet pump; 30. Chimney. Detailed Implementation

[0039] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0041] See Figure 1 This invention provides a shale dry distillation wastewater resource treatment and reuse system, including a raw water storage tank 1, a reboiler 2, an alkali storage tank 3, a stripping ammonia stripping tower 4, a primary condenser 5, a secondary condenser 6, a recovered ammonia water storage tank 7, an oxidation circulator 8, and a desulfurization tower 9.

[0042] Among them, the raw water storage tank 1 is connected to the middle section of the stripping ammonia tower 4 through a pipeline. The raw water storage tank 1 is used to transport shale dry distillation wastewater to the stripping ammonia tower 4.

[0043] The reboiler 2 is connected to the middle section of the stripping ammonia tower 4 via a pipeline. The reboiler 2 is used to transport steam to the stripping ammonia tower 4.

[0044] Among them, the alkali storage tank 3 is connected to the middle section of the stripping ammonia tower 4 through a pipeline. The alkali storage tank 3 is used to mix the shale dry distillation wastewater and alkali solution transported to the stripping ammonia tower 4.

[0045] The pipeline at the top of the ammonia stripping tower 4 is divided into two lines, connecting to the primary condenser 5 and the secondary condenser 6. The primary condenser 5 is connected to the secondary condenser 6 via a pipeline, and the secondary condenser 6 is connected to the ammonia recovery storage tank 7 via a pipeline. The primary condenser 5 is used for primary condensation and liquefaction of the ammonia vapor discharged from the ammonia stripping tower 4, and the secondary condenser 6 is used for secondary condensation and liquefaction of the ammonia vapor discharged from the ammonia stripping tower 4. The ammonia recovery storage tank 7 is used to store the ammonia water produced by condensation and liquefaction.

[0046] The ammonia recovery storage tank 7 is connected to the lower section of the oxidation circulator 8 via a pipeline. One side of the lower section of the oxidation circulator 8 is connected to an oxygen input pipeline 10, and the other side of the lower section of the oxidation circulator 8 is connected to an oxygen output pipeline 11, which connects to the middle section of the desulfurization tower 9. An ammonia liquid input pipeline 12 is connected between the lower section of the oxidation circulator 8 and the middle section of the desulfurization tower 9. The lower section of the desulfurization tower 9 is connected to a boiler flue gas input pipeline 13 and an ammonium sulfate output pipeline 14. The desulfurization tower 9 is used to desulfurize the boiler flue gas using the ammonia water and oxygen transported by the oxidation circulator 8.

[0047] In this embodiment, the upper end of the raw water storage tank 1 is connected to a shale distillation wastewater inlet pipeline 15, which is used to transport shale distillation wastewater to the raw water storage tank 1. The bottom of the reboiler 2 is connected to a steam inlet pipeline 16, and a steam pump 17 is installed on the steam inlet pipeline 16; the steam inlet pipeline 16 transports steam to the reboiler 2 through the steam pump 17. The alkali storage tank 3 is connected to an alkali inlet pipeline 18, which is used to transport NaOH alkali solution to the alkali storage tank 3.

[0048] Specifically, the pre-treated wastewater from shale distillation first enters the feed water storage tank 1. After being pressurized in the feed water storage tank 1, it enters the middle section of the stripping ammonia stripping tower 4 from the bottom of the tank. Simultaneously, the NaOH alkali solution is released after entering the alkali solution storage tank 3. Before entering the middle section of the stripping ammonia stripping tower 4, it is thoroughly mixed with the shale distillation wastewater. External steam is pressurized by steam pump 17 and heated to 105°C in reboiler 2 before entering the middle section of the stripping ammonia stripping tower 4. The shale distillation wastewater, NaOH alkali solution, and steam are mixed for stripping.

[0049] The ammonia stripping tower 4 operates at a pressure of 0.3 MPa, with a top temperature of <93℃ and a bottom temperature of <104℃. The pH of the mixed liquid is 10-11. The concentration of ammonia in the dry distillation wastewater is lower than that in the steam. A gas-liquid mass transfer reaction occurs on the packing surface of the ammonia stripping tower 4. The steam generated after heating the dry distillation wastewater removes the ammonia nitrogen from the dry distillation wastewater, thus achieving ammonia stripping from the dry distillation wastewater.

[0050] Among them, after the stripping wastewater is mixed with NaOH alkaline solution, the hydrogen sulfide in the wastewater is neutralized by NaOH. The ammonia nitrogen concentration in the wastewater is low, and it can be discharged from the bottom of the stripping ammonia stripping tower 4 for subsequent biochemical treatment. The N3H content in the effluent from the bottom of the stripping ammonia stripping tower 4 is <100mg / L.

[0051] In this embodiment, a dilute ammonia water circulation pipeline 19 is connected between the middle section of the primary condenser 5 and the stripping ammonia tower 4. The dilute ammonia water circulation pipeline 19 is equipped with a dilute ammonia water circulation pump 20. The dilute ammonia water circulation pipeline 19 uses the dilute ammonia water circulation pump 20 to return the liquefied dilute ammonia water from the primary condenser 5 to the stripping ammonia tower 4 for concentration and purification.

[0052] Specifically, the ammonia vapor obtained from ammonia stripping is discharged from the top of ammonia stripping tower 4. The ammonia vapor temperature is <45℃, the N3H concentration is >15%, and the H2S content is <5mg / L. After discharge, it enters the primary condenser 5, where most of the ammonia vapor is liquefied into dilute ammonia water and then returned to the middle section of ammonia stripping tower 4 by dilute ammonia water circulation pump 20 for further concentration and purification. The remaining ammonia vapor and the concentrated and purified ammonia vapor enter the secondary condenser 6 for deep liquefaction to produce ammonia water with an N3H concentration >20%. The produced ammonia water enters the ammonia water recovery storage tank 7 and is used as a raw material for subsequent desulfurization operations.

[0053] In this embodiment, a water washing circulation input pipeline 21 is connected between one side of the upper section of the oxidation circulator 8 and the upper section of the desulfurization tower 9. A water washing circulation pump 22 is installed on the water washing circulation input pipeline 21. A water washing circulation output pipeline 23 is connected between the other side of the upper section of the oxidation circulator 8 and the water washing section of the desulfurization tower 9. An ammonia liquid pump 24 is installed on the ammonia liquid input pipeline 12, and the ammonia liquid input pipeline 12 delivers ammonia water to the desulfurization tower 9 through the ammonia liquid pump 24.

[0054] Specifically, the ammonia solution with a concentration of 20% or higher produced is pressurized in the ammonia storage tank and enters the lower oxidation section of the oxidation cycler 8. On the other side of the lower oxidation cycler 8, the ammonia solution is pressurized by the ammonia pump 24 and pumped into the spray desulfurization section in the middle of the desulfurization tower 9 to absorb and desulfurize the boiler flue gas. After the ammonia solution absorbs the boiler flue gas, it generates an ammonium sulfite solution, which continues to react with SO2 in the flue gas at a reasonable concentration obtained through limited experiments, preventing the ammonia solution from evaporating into the flue gas. Simultaneously, oxygen is introduced through the oxygen inlet at the bottom of the oxidation cycler 8 and blown into the lower concentration section of the desulfurization tower 9 from the bottom on the other side. This oxygen is used to oxidize the ammonium sulfite solution formed by the absorption of SO2 in the flue gas by the ammonia solution in the desulfurization section into an ammonium sulfate solution.

[0055] In this embodiment, an ammonium sulfate circulation pipeline 25 is connected to one side of the lower section of the desulfurization tower 9, and an ammonium sulfate circulation pump 26 is installed on the ammonium sulfate circulation pipeline 25; an ammonium sulfate discharge pump 27 is installed on the ammonium sulfate output pipeline 14; a water washing pipeline 28 is connected to the upper section of the desulfurization tower 9, and an inlet pump 29 is installed on the water washing pipeline 28; the water washing pipeline 28 uses the inlet pump 29 to wash and cool the purified flue gas; a chimney 30 is connected to the top of the desulfurization tower 9, and the chimney 30 is used to discharge the purified flue gas.

[0056] Specifically, boiler flue gas enters from the concentration section at the bottom of desulfurization tower 9, and undergoes absorption and reaction with countercurrent ammonia water in the middle spray desulfurization section. The remaining unreacted flue gas continues upward into the upper water washing section. The upper water washing section uses water pump 29 to pressurize and cool the purified flue gas. After washing, the water flows back into the upper section of oxidation circulator 8. Simultaneously, the water washing circulation pump 22 on one side of the upper section of oxidation circulator 8 pumps circulating water into the water washing section of desulfurization tower 9, achieving the purpose of thorough water washing of the purified flue gas and improving resource utilization.

[0057] Meanwhile, the purified flue gas, after being thoroughly washed with water, is discharged from the top exhaust port of desulfurization tower 9 and then fed into chimney 30 for emission. The SO2 content of the purified flue gas after desulfurization is <30mg / Nm³. 3 Ammonia content in flue gas ≤5mg / Nm 3 The desulfurization efficiency can reach 98%. After the flue gas is absorbed and reacted in the middle desulfurization section of desulfurization tower 9, residual waste liquid ammonium sulfite solution is produced. This solution flows into the lower concentration section of desulfurization tower 9 and combines with oxygen to oxidize into ammonium sulfate solution. The resulting dilute ammonium sulfate solution is pressurized and circulated back to the upper end of the concentration section by ammonium sulfate circulation pump 26 on one side of the bottom of desulfurization tower 9 for further washing and concentration of the flue gas. During the process of cooling the flue gas, the ammonium sulfate circulating liquid is further oxidized and concentrated to obtain a solution concentration that meets the requirements. The resulting high-concentration ammonium sulfate solution is discharged by ammonium sulfate discharge pump 27 connected to the bottom of desulfurization tower 9 for subsequent treatment and resource utilization.

[0058] Support Figure 1 and Figure 2 The present invention also provides a process for the resource-based treatment and reuse of shale carbonization wastewater, which adopts the above-mentioned shale carbonization wastewater resource-based treatment and reuse system and includes the following steps:

[0059] The pre-treated shale distillation wastewater enters the raw water storage tank 1. After being pressurized in the raw water storage tank 1, it enters the middle section of the stripping ammonia stripping tower 4. The alkaline solution is released after entering the alkaline solution storage tank 3 and is mixed with the shale distillation wastewater before entering the middle section of the stripping ammonia stripping tower 4.

[0060] After being pressurized, the external steam enters the reboiler 2 for heating and then enters the middle section of the ammonia stripping tower 4, where steam, shale dry distillation wastewater, and alkaline solution are mixed for stripping.

[0061] The ammonia vapor obtained from the stripping of ammonia is discharged from the top of the stripping ammonia tower 4. After being discharged, it enters the first-stage condenser 5. Part of the ammonia vapor is liquefied into dilute ammonia water by the first-stage condenser and flows back to the middle section of the stripping ammonia tower 4 for further concentration and purification. The remaining ammonia vapor and the concentrated and purified ammonia vapor enter the second-stage condenser 6 to liquefy and produce ammonia water. The produced ammonia water enters the ammonia water recovery storage tank 7 and is used as a raw material for desulfurization.

[0062] Ammonia water is pressurized in the ammonia water recovery storage tank 7 and enters the lower oxidation section of the oxidation circulator 8. On the other side of the lower section of the oxidation circulator 8, the ammonia water is pressurized and pumped into the middle spray desulfurization section of the desulfurization tower 9 to absorb and desulfurize the boiler flue gas. After the boiler flue gas is absorbed by ammonia water, an ammonium sulfite solution is generated. Oxygen is blown into the lower concentration section of the desulfurization tower 9 through the oxidation circulator 8 to oxidize the ammonium sulfite solution formed in the spray desulfurization section, and after oxidation, an ammonium sulfate solution is generated.

[0063] Boiler flue gas enters the concentration section from the bottom of desulfurization tower 9. In the desulfurization section, it is absorbed and reacted with countercurrent ammonia water. The remaining unreacted flue gas continues to enter the upper water washing section of desulfurization tower 9. The upper water washing section performs water washing and cooling operation on the purified flue gas.

[0064] After washing, the washing liquid flows back into the upper section of the oxidation circulator 8. The upper section of the oxidation circulator 8 pumps the circulating water into the washing section of the desulfurization tower 9 to form a washing cycle. The purified flue gas after washing is discharged from the top exhaust port of the desulfurization tower 9 and then discharged into the chimney 30.

[0065] The resulting dilute ammonium sulfate solution is pressurized and circulated back to the upper part of the concentration section from the bottom of the desulfurization tower 9 to wash and concentrate the flue gas. The high-concentration ammonium sulfate solution is discharged from the bottom of the desulfurization tower 9 and then utilized as a resource.

[0066] In this embodiment, the remaining shale distillation wastewater after pretreatment first enters the raw water storage tank 1. After being pressurized in the raw water storage tank 1, it enters the middle section of the stripping ammonia stripping tower 4 from the bottom of the tank. At the same time, the NaOH alkaline solution is released after entering the alkaline solution storage tank 3. Before entering the middle section of the stripping ammonia stripping tower 4, it is fully mixed with the shale distillation wastewater. External steam is pressurized by steam pump 17 and heated to 105°C in reboiler 2 before entering the middle section of the stripping ammonia stripping tower 4. The shale distillation wastewater, NaOH alkaline solution, and steam are mixed for stripping.

[0067] In this embodiment, the operating pressure of the ammonia stripping tower 4 is 0.3 MPa, the working temperature at the top of the tower is <93℃, the working temperature at the bottom of the tower is <104℃, and the pH of the mixed liquid is 10-11. Taking advantage of the fact that the concentration of ammonia in the dry distillation wastewater is lower than that in the steam, a gas-liquid mass transfer reaction is carried out on the surface of the packing of the ammonia stripping tower 4. The steam generated after heating the dry distillation wastewater is used to remove the ammonia nitrogen in the dry distillation wastewater, thereby realizing the stripping of ammonia from the dry distillation wastewater.

[0068] In this embodiment, after the stripping wastewater is mixed with NaOH alkaline solution, the hydrogen sulfide in the wastewater is neutralized by NaOH. The ammonia nitrogen concentration in the wastewater is low, and it can be discharged from the bottom of the stripping ammonia stripping tower 4 for subsequent biochemical treatment. The N3H content in the effluent from the bottom of the stripping ammonia stripping tower 4 is <100mg / L.

[0069] In this embodiment, the ammonia vapor obtained from ammonia stripping is discharged from the top of the ammonia stripping tower 4. The ammonia vapor temperature is <45℃, the N3H concentration is >15%, and the H2S content is <5mg / L. After discharge, it enters the primary condenser 5, where most of the ammonia vapor is liquefied into dilute ammonia water and then returned to the middle section of the ammonia stripping tower 4 by the dilute ammonia water circulation pump 20 for further concentration and purification. The remaining ammonia vapor and the concentrated and purified ammonia vapor enter the secondary condenser 6 for deep liquefaction to produce ammonia water with an N3H concentration >20%. The produced ammonia water enters the ammonia water recovery storage tank 7 and is used as a raw material for subsequent desulfurization operations.

[0070] In this embodiment, the ammonia water with a concentration of 20% or higher produced is pressurized in an ammonia water storage tank and enters the lower oxidation section of the oxidation circulator 8. On the other side of the lower oxidation circulator 8, the ammonia water is pressurized by an ammonia liquid pump 24 and pumped into the spray desulfurization section in the middle of the desulfurization tower 9 to absorb and desulfurize the boiler flue gas. After the boiler flue gas is absorbed by the ammonia water, an ammonium sulfite solution is generated. This solution continues to react with SO2 in the flue gas at a reasonable concentration obtained through a limited number of experiments, preventing the ammonia water from evaporating into the flue gas. Simultaneously, oxygen is introduced through the oxygen inlet at the bottom of the oxidation circulator 8 and blown into the lower concentration section of the desulfurization tower 9 from the bottom on the other side. This oxygen is used to oxidize the ammonium sulfite solution formed by the absorption of SO2 in the flue gas by the ammonia water in the desulfurization section into an ammonium sulfate solution.

[0071] In this embodiment, boiler flue gas enters from the concentration section at the bottom of desulfurization tower 9, and undergoes absorption and reaction with countercurrent ammonia water in the middle spray desulfurization section. The remaining unreacted flue gas continues to enter the upper water washing section. The upper water washing section pressurizes and inputs water through water pump 29 to perform water washing and cooling operations on the purified flue gas. After washing, the water wash liquid flows back into the upper section of oxidation circulator 8. At the same time, the water washing circulation pump 22 on one side of the upper section of oxidation circulator 8 pumps circulating water into the water washing section of desulfurization tower 9, achieving the purpose of thorough water washing of purified flue gas and improving resource utilization.

[0072] In this embodiment, the purified flue gas, after thorough water washing, is discharged from the top exhaust port of desulfurization tower 9 and then fed into chimney 30 for emission. The SO2 content of the desulfurized flue gas is <30mg / Nm3, and the ammonia content is ≤5mg / Nm3. 3The desulfurization efficiency can reach 98%. After the flue gas is absorbed and reacted in the middle desulfurization section of desulfurization tower 9, residual waste liquid ammonium sulfite solution is produced. This solution flows into the lower concentration section of desulfurization tower 9 and combines with oxygen to oxidize into ammonium sulfate solution. The resulting dilute ammonium sulfate solution is pressurized and circulated back to the upper end of the concentration section by ammonium sulfate circulation pump 26 on one side of the bottom of desulfurization tower 9 for further washing and concentration of the flue gas. During the process of cooling the flue gas, the ammonium sulfate circulating liquid is further oxidized and concentrated to obtain a solution concentration that meets the requirements. The resulting high-concentration ammonium sulfate solution is discharged by ammonium sulfate discharge pump 27 connected to the bottom of desulfurization tower 9 for subsequent treatment and resource utilization.

[0073] In summary, this invention possesses advantages such as good resource utilization performance, low energy consumption, no environmental pollution, and good stability, meeting the requirements of green chemical production. It reduces the consumption of steam and alkali solution, efficiently utilizes ammonia resources, significantly reduces energy consumption, and substantially lowers equipment investment. This invention improves ammonia water quality, reduces the cost of ammonia stripping treatment in shale distillation wastewater, and lowers the cost of flue gas desulfurization raw materials, turning waste into treasure. It enables low-carbon, environmentally friendly, efficient, and low-cost resource utilization of ammonia stripping from shale distillation wastewater. This invention belongs to a new type of clean technology for the circular economy, possessing advantages such as high desulfurization efficiency, no secondary pollution, resource recovery of sulfur dioxide, and economical solution to ammonia loss problems. The produced ammonium sulfate solution can also be used for soil improvement, meeting the requirements of the circular economy, and further achieving resource utilization and environmental protection requirements.

[0074] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0075] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A system for the resource-based treatment and reuse of shale carbonization wastewater, characterized in that, It includes a raw water storage tank (1), a reboiler (2), an alkali storage tank (3), a stripping ammonia stripping tower (4), a primary condenser (5), a secondary condenser (6), a recovered ammonia water storage tank (7), an oxidation circulator (8), and a desulfurization tower (9). The raw water storage tank (1) is connected to the middle section of the stripping ammonia tower (4) via a pipeline. The raw water storage tank (1) is used to transport shale dry distillation wastewater to the stripping ammonia tower (4). The reboiler (2) is connected to the middle section of the stripping ammonia tower (4) via a pipeline. The reboiler (2) is used to deliver steam to the stripping ammonia tower (4). The alkali storage tank (3) is connected to the middle section of the stripping ammonia tower (4) via a pipeline. The alkali storage tank (3) is used to mix the shale dry distillation wastewater and alkali solution that are transported to the stripping ammonia tower (4). The pipeline at the top of the ammonia stripping tower (4) is connected in two directions to the primary condenser (5) and the secondary condenser (6). The primary condenser (5) is connected to the secondary condenser (6) via a pipeline, and the secondary condenser (6) is connected to the ammonia recovery storage tank (7) via a pipeline. The primary condenser (5) is used for primary condensation and liquefaction of the ammonia vapor discharged from the ammonia stripping tower (4), and the secondary condenser (6) is used for secondary condensation and liquefaction of the ammonia vapor discharged from the ammonia stripping tower (4). The ammonia recovery storage tank (7) is used to store the ammonia water produced by condensation and liquefaction. The ammonia recovery tank (7) is connected to the lower section of the oxidation circulator (8) via a pipeline. One side of the lower section of the oxidation circulator (8) is connected to an oxygen input pipeline (10), and the other side of the lower section of the oxidation circulator (8) is connected to an oxygen output pipeline (11) which is connected to the middle section of the desulfurization tower (9). An ammonia liquid input pipeline (12) is connected between the lower section of the oxidation circulator (8) and the middle section of the desulfurization tower (9). The lower section of the desulfurization tower (9) is connected to a boiler flue gas input pipeline (13) and an ammonium sulfate output pipeline (14). The desulfurization tower (9) is used to desulfurize the boiler flue gas using the ammonia water and oxygen transported by the oxidation circulator (8). A water washing circulation input pipeline (21) is connected between the upper section of the oxidizing circulator (8) and the upper section of the desulfurization tower (9). A water washing circulation pump (22) is provided on the water washing circulation input pipeline (21). A water washing circulation output pipeline (23) is connected between the other side of the upper section of the oxidizing circulator (8) and the water washing section of the desulfurization tower (9).

2. The shale carbonization wastewater resource treatment and reuse system according to claim 1, characterized in that, The upper end of the raw water storage tank (1) is connected to a shale dry distillation wastewater inlet pipeline (15), which is used to transport shale dry distillation wastewater to the raw water storage tank (1).

3. The shale carbonization wastewater resource treatment and reuse system according to claim 2, characterized in that, The bottom of the reboiler (2) is connected to a steam input pipe (16), and a steam pump (17) is provided on the steam input pipe (16); the steam input pipe (16) delivers steam to the reboiler (2) through the steam pump (17).

4. The shale carbonization wastewater resource treatment and reuse system according to claim 3, characterized in that, The alkali storage tank (3) is connected to an alkali input pipeline (18), which is used to transport NaOH alkali solution to the alkali storage tank (3).

5. The shale carbonization wastewater resource treatment and reuse system according to claim 4, characterized in that, A dilute ammonia water circulation pipeline (19) is connected between the middle section of the primary condenser (5) and the stripping ammonia tower (4). The dilute ammonia water circulation pipeline (19) is equipped with a dilute ammonia water circulation pump (20). The dilute ammonia water circulation pipeline (19) uses the dilute ammonia water circulation pump (20) to return the liquefied dilute ammonia water from the primary condenser (5) to the stripping ammonia tower (4) for concentration and purification.

6. The shale carbonization wastewater resource treatment and reuse system according to claim 5, characterized in that, The ammonia inlet pipeline (12) is equipped with an ammonia pump (24), and the ammonia inlet pipeline (12) delivers ammonia water to the desulfurization tower (9) through the ammonia pump (24).

7. A shale carbonization wastewater resource treatment and reuse system according to claim 6, characterized in that, The lower section of the desulfurization tower (9) is connected to an ammonium sulfate circulation pipeline (25), and an ammonium sulfate circulation pump (26) is installed on the ammonium sulfate circulation pipeline (25); an ammonium sulfate discharge pump (27) is installed on the ammonium sulfate output pipeline (14). The upper section of the desulfurization tower (9) is connected to a water washing pipeline (28), and an inlet pump (29) is provided on the water washing pipeline (28); the water washing pipeline (28) uses the inlet pump (29) to wash and cool the purified flue gas. The top of the desulfurization tower (9) is connected to a chimney (30), which is used to discharge the purified flue gas.

8. A process for the resource-based treatment and reuse of shale carbonization wastewater, employing the shale carbonization wastewater resource-based treatment and reuse system according to any one of claims 1 to 7, characterized in that, Includes the following steps: Shale distillation wastewater that has undergone pretreatment enters the raw water storage tank (1). After being pressurized by the raw water storage tank (1), it enters the middle section of the stripping ammonia tower (4). The alkali solution is released after entering the alkali solution storage tank (3) and is mixed with the shale distillation wastewater before entering the middle section of the stripping ammonia tower (4). After being pressurized, the external steam enters the reboiler (2) for heating and then enters the middle section of the stripping ammonia tower (4). Steam, shale dry distillation wastewater and alkaline solution are mixed for stripping. The ammonia vapor obtained from the stripping of ammonia is discharged from the top of the stripping ammonia tower (4). After being discharged, it enters the first-stage condenser (5). Part of the ammonia vapor is liquefied into dilute ammonia water by the first-stage condenser and flows back to the middle section of the stripping ammonia tower (4) for further concentration and purification. The remaining ammonia vapor and the ammonia vapor after concentration and purification enter the second-stage condenser (6) to liquefy and produce ammonia water. The produced ammonia water enters the ammonia water recovery storage tank (7) and is then used as a raw material for desulfurization. Ammonia water is pressurized in the ammonia water storage tank (7) and enters the lower oxidation section of the oxidation circulator (8). Ammonia water is pressurized on the other side of the lower section of the oxidation circulator (8) and pumped into the middle spray desulfurization section of the desulfurization tower (9) to absorb and desulfurize the boiler flue gas. After the boiler flue gas is absorbed by ammonia water, an ammonium sulfite solution is generated. Oxygen is blown into the lower concentration section of the desulfurization tower (9) through the oxidation circulator (8) to oxidize the ammonium sulfite solution formed in the spray desulfurization section. After oxidation, an ammonium sulfate solution is generated. Boiler flue gas enters the concentration section from the bottom of the desulfurization tower (9). In the desulfurization section, it is absorbed and reacted with countercurrent ammonia water. The remaining unreacted flue gas continues to enter the upper water washing section of the desulfurization tower (9). The upper water washing section performs water washing and cooling operation on the purified flue gas. After being washed, the washing liquid flows back into the upper section of the oxidation circulator (8). The upper section of the oxidation circulator (8) pumps the circulating water into the washing section of the desulfurization tower (9) to form a washing cycle. The purified flue gas, after being washed with water, is discharged from the top exhaust port of the desulfurization tower (9) and then fed into the chimney (30) for emission. The resulting dilute ammonium sulfate solution is pressurized and circulated back to the upper part of the concentration section from the bottom of the desulfurization tower (9) to wash and concentrate the flue gas. The high-concentration ammonium sulfate solution is discharged from the bottom of the desulfurization tower (9) and then utilized as a resource.

9. The shale carbonization wastewater resource treatment and reuse process according to claim 8, characterized in that, The operating pressure of the stripping ammonia tower (4) is 0.3 MPa, the working temperature at the top of the stripping ammonia tower (4) is <93℃, the working temperature at the bottom of the stripping ammonia tower (4) is <104℃, and the pH of the mixed liquid is 10-11.

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