A device for treating sewage containing sulphurous ammonia

Abstract

The application discloses a sulfur-containing ammonia sewage treatment device and relates to the technical field of sewage treatment. The sulfur-containing ammonia sewage is pressurized by a sewage pressurizing pump and preheated by a raw material sewage preheater, and then enters a sewage dehydrocarbon column. The overhead gas is condensed and separated, the incondensable gas is discharged, and the liquid phase flows to a water-containing light oil storage tank. The dehydrocarbonized sewage is heat-exchanged and enters a sewage buffer tank, and then is divided into two streams by a sewage delivery pump. One stream is cooled and enters the top of a sewage stripping tower, and the other stream is heat-exchanged and enters the middle and upper part of the sewage stripping tower. A reboiler provides heat for the sewage stripping tower, and the sewage stripping tower removes hydrogen sulfide and ammonia. The gas phase is delivered to a sulfur recovery system after being cooled and separated, the liquid phase is delivered to a fractionating column reflux tank, and the middle ammonia gas is delivered to an ammonia water recovery system after being heat-exchanged, so that efficient treatment and resource recovery of the sulfur-containing ammonia sewage are realized. The application solves the problems of secondary pollution and high operation and maintenance cost in the prior art.

Description

Technical Field

[0001] This application relates to the field of wastewater treatment technology, and in particular to a device for treating sulfur-containing ammonia wastewater. Background Technology

[0002] The wastewater stripping system of the DCC (Catalytic Residue Crack) unit uses a single-tower side-stream ammonia extraction process to remove ammonia and hydrogen sulfide from sulfur-containing ammonia wastewater. Acidic hydrogen sulfide is extracted from the top of the tower, ammonia is extracted from the side stream, and purified water from the bottom is sent to a wastewater treatment plant. Because the sulfur-containing ammonia wastewater contains a large amount of oil, the light components vaporize within the wastewater stripping tower, making it difficult to control key operating parameters and prone to tower overflow. The oil content of the extracted acidic hydrogen sulfide from the top, the extracted ammonia from the side stream, and the purified water from the bottom all exceed design values. Ammonia and hydrogen sulfide cannot be recovered and reused, significantly impacting environmental performance.

[0003] Industrially, deep filtration is commonly used for oil removal. This process, in addition to initial oil removal, incorporates an oil-water separator containing a graphene-based oleophilic-hydrophobic filter element to effectively treat emulsified and dissolved oils, further reducing the oil content. Finally, a hollow fiber membrane filter is used to block and collect dissolved oil in the wastewater, thus removing it. The total oil content of the treated wastewater is ≤20mg / L. While this process effectively addresses the oil content issue in the influent of wastewater stripping, it introduces secondary sludge discharge during the process. Furthermore, filter rods, filter elements, and hollow fiber membrane modules are consumables, susceptible to membrane fouling, requiring regular replacement and resulting in high operating and maintenance costs. Utility Model Content

[0004] This application provides a sulfur-containing ammonia wastewater treatment device, which solves the problems of secondary sewage discharge and high operation and maintenance costs in the existing technology during the wastewater treatment process.

[0005] This application provides a sulfur-containing ammonia wastewater treatment device, including a wastewater pressurization pump, a raw wastewater preheater, a wastewater dehydrogenation tower, a tower top condenser, a separator, a reboiler, a wastewater buffer tank, a wastewater transfer pump, a sulfur-containing wastewater recooler, a heat exchanger between rich ammonia gas and sulfur-containing wastewater, a heat exchanger between sulfur-containing wastewater and purified water, a wastewater stripping tower, a reboiler, an acid gas cooler, a separator, and a purified water pump. The inlet of the wastewater pressurization pump is used to input sulfur-containing ammonia wastewater, and the outlet of the wastewater pressurization pump is connected to the inlet of the raw wastewater preheater, which is connected to the inlet of the wastewater dehydrogenation tower. The gas phase outlet of the wastewater dehydrogenation tower is connected to the inlet of the tower top condenser, and the outlet of the tower top condenser is connected to the separator. The reboiler is connected to the wastewater dehydrogenation tower to form a heat source circulation path to provide a heat source for the wastewater dehydrogenation tower. The liquid phase outlet of the wastewater dehydrogenation tower is connected to the raw wastewater... The water preheater is connected to the inlet of the sewage buffer tank; the inlet of the sewage transfer pump is connected to the outlet of the sewage buffer tank, and the outlet of the sewage transfer pump is connected to the inlets of the sulfur-containing sewage recooler and the ammonia-rich gas-sulfur-containing sewage heat exchanger; the outlet of the ammonia-rich gas-sulfur-containing sewage heat exchanger is connected to the inlet of the sulfur-containing sewage-purified water heat exchanger, and then connected to the sewage stripping tower; the reboiler is connected to the sewage stripping tower to form a heat source circulation path to provide a heat source for the sewage stripping tower; the gas phase outlet of the sewage stripping tower is connected to the inlet of the separator through the acid gas cooler; the inlet of the purified water pump is connected to the liquid phase outlet of the sewage stripping tower, and the outlet of the purified water pump is connected to the sulfur-containing sewage-purified water heat exchanger; the ammonia gas extracted from the middle of the sewage stripping tower is transported to the ammonia-rich gas-sulfur-containing sewage heat exchanger, where it exchanges heat with the sulfur-containing ammonia sewage, and then is transported to the ammonia water recovery system.

[0006] In one possible implementation, the inlets of both the reboiler and the re-boiler are used to input low-pressure steam, and the outlets of both the reboiler and the re-boiler are connected to the steam condensate pipeline network.

[0007] In one possible implementation, the upper gas phase outlet of the separator is connected to the flare system, and the lower liquid phase outlet of the separator is connected to the water-containing light oil storage tank. Nitrogen introduced from the outside enters the separator and then enters the flare system from the upper gas phase outlet of the separator.

[0008] In one possible implementation, the upper gas phase outlet of the separator is connected to the sulfur recovery system, and the lower liquid phase outlet of the separator is connected to the fractionation tower reflux tank.

[0009] In one possible implementation, both the wastewater dehydrocarbonization tower and the wastewater stripping tower adopt a plate tower structure.

[0010] In one possible implementation, centrifugal pumps are used for the sewage booster pump, sewage transfer pump, and purified water pump.

[0011] In one possible implementation, an electric valve is also included; the electric valve is installed at the outlet of the sewage booster pump, sewage transfer pump, and purified water pump.

[0012] The one or more technical solutions provided in this application have at least the following technical effects or advantages: Addressing the problem of high oil content in sulfur-containing ammonia wastewater, this application utilizes a wastewater dehydrogenation tower with steam stripping to remove most of the oil and small amounts of hydrogen sulfide and ammonia from the top of the tower, achieving efficient oil removal from sulfur-containing ammonia wastewater. Simultaneously, hydrogen sulfide and ammonia are stripped from the wastewater in the stripping tower, and the ammonia gas extracted from the middle of the tower is transported to an ammonia water recovery system to produce ammonia water, achieving resource recovery and utilization. The sulfur-containing ammonia wastewater after dehydrogenation at the bottom of the dehydrogenation tower enters the subsequent treatment stage after heat exchange. The two streams of wastewater separated by the wastewater transfer pump participate in different heat exchange processes, fully utilizing the thermal energy within the system, reducing additional heat input, lowering energy consumption, and improving the overall energy efficiency of the device. This application does not require additional consumables or reagents; it achieves effective treatment and resource recovery of sulfur-containing ammonia wastewater solely through reasonable process design and equipment configuration. Compared to traditional treatment methods that require large amounts of chemicals or frequent replacement of consumables, this method significantly reduces the treatment cost of sulfur-containing ammonia wastewater, improves economic efficiency, and provides an economical and feasible solution for treating sulfur-containing ammonia wastewater. It also solves the problems of secondary sewage discharge and high operation and maintenance costs associated with existing technologies. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments of this application or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a schematic diagram of a sulfur-containing ammonia wastewater treatment device provided in an embodiment of this application.

[0015] Icons: 1-Wastewater booster pump; 2-Raw wastewater preheater; 3-Wastewater dehydrocarbonization tower; 4-Tower top condenser; 5-Separator; 6-Reboiler; 7-Wastewater buffer tank; 8-Wastewater transfer pump; 9-Sulfur-containing wastewater recooler; 10-Ammonia-rich gas and sulfur-containing wastewater heat exchanger; 11-Sulfur-containing wastewater and purified water heat exchanger; 12-Wastewater stripping tower; 13-Reboiler; 14-Acid gas cooler; 15-Separating tank; 16-Purified water pump; 17-Ammonia water recovery system; 18-Steam condensate pipeline network; 19-Flame system; 20-Water-containing light oil storage tank; 21-Sulfur recovery system; 22-Fracturing tower reflux tank. Detailed Implementation

[0016] In the description of the embodiments of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the embodiments of this application and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances.

[0017] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0018] Figure 1 This is a schematic diagram of a sulfur-containing ammonia wastewater treatment device provided in an embodiment of this application. Figure 1 As shown, the sulfur-containing ammonia wastewater treatment device includes a wastewater pressurization pump 1, a raw wastewater preheater 2, a wastewater dehydrocarbonization tower 3, a tower top condenser 4, a separator 5, a reboiler 6, a wastewater buffer tank 7, a wastewater transfer pump 8, a sulfur-containing wastewater recooler 9, a heat exchanger between rich ammonia gas and sulfur-containing wastewater 10, a heat exchanger between sulfur-containing wastewater and purified water 11, a wastewater stripping tower 12, a reboiler 13, an acid gas cooler 14, a separator 15, and a purified water pump 16.

[0019] The inlet of the wastewater booster pump 1 is used to input sulfur-containing ammonia wastewater. The outlet of the wastewater booster pump 1 is connected to the inlet of the raw wastewater preheater 2, and the outlet of the raw wastewater preheater 2 is connected to the inlet of the wastewater dehydrocarbonization tower 3.

[0020] Specifically, the sulfur-containing ammonia wastewater originates from the DCC (Catalytic Crack) unit. After being pressurized by wastewater booster pump 1, the sulfur-containing ammonia wastewater flows out from the outlet of pump 1 and is transported to the inlet of the raw wastewater preheater 2. The raw wastewater preheater 2 is a device for preheating wastewater. After preheating, the sulfur-containing ammonia wastewater flows out from the outlet of the raw wastewater preheater 2 and is transported to the inlet of the wastewater dehydrocarbonization tower 3, where it begins the next stage of the treatment process.

[0021] The gas phase outlet of the wastewater dehydrocarbon removal tower 3 is connected to the inlet of the top condenser 4, and the outlet of the top condenser 4 is connected to the separator 5. The upper gas phase outlet of the separator 5 is connected to the flare system 19, and the lower liquid phase outlet of the separator 5 is connected to the water-containing light oil storage tank 20. Nitrogen introduced from the outside enters the separator 5 and then enters the flare system 19 from the upper gas phase outlet of the separator 5.

[0022] Specifically, the wastewater dehydrocarbonization tower 3 vaporizes most of the oily substances and small amounts of hydrogen sulfide and ammonia in the sulfur-containing ammonia wastewater, forming a gaseous mixture. This gaseous mixture escapes from the gaseous outlet of the wastewater dehydrocarbonization tower 3 and is transported to the inlet of the top condenser 4. After entering the top condenser 4, the gaseous mixture undergoes sufficient heat exchange with the cooling medium. Under the action of the cooling medium, the temperature of the gaseous mixture drops rapidly, and the condensable gases are condensed into liquids, while the non-condensable gases remain gaseous. The mixture after condensation flows out from the outlet of the top condenser 4 and is transported to the separator 5. The separator 5 is an important site for gas-liquid separation. Due to the density difference between the gaseous and liquid substances, the mixture entering the separator 5 naturally stratifies within the separator 5. The separated gaseous substances accumulate in the upper part of the separator 5, while the liquid substances deposit in the lower part of the separator 5. The upper gaseous outlet of the separator 5 is connected to the flare system 19. Non-condensable gases, including some light hydrocarbons and other harmful gases, are safely transported to the flare system 19 through the upper gas phase outlet. In the flare system 19, these harmful gases are combusted and converted into relatively harmless substances that are released into the atmosphere, effectively avoiding direct harm to the environment and human health. The lower liquid phase outlet of separator 5 is connected to the water-containing light oil storage tank 20. Liquid substances such as water-containing sludge deposited at the bottom are collected through the lower liquid phase outlet and transported to the water-containing light oil storage tank 20 for buffering. The substances in the water-containing light oil storage tank 20 are recycled through the fractionation tower reflux tank 22 to maximize resource utilization and minimize pollution.

[0023] In addition, externally introduced nitrogen also enters separator 5. Nitrogen, as an inert gas, plays a protective and purging role in the device. The nitrogen entering separator 5 mixes with the gas inside and then enters the flare system 19 from the upper gas phase outlet of separator 5. The introduction of nitrogen helps maintain stable pressure within separator 5, prevents air from entering the system and causing hazards, and also dilutes the concentration of harmful gases to a certain extent, ensuring the safety and stability of the entire treatment process.

[0024] The reboiler 6 is connected to the wastewater dehydrocarbon tower 3 to form a heat source circulation path, which is used to provide a heat source for the wastewater dehydrocarbon tower 3.

[0025] The liquid phase outlet of the wastewater dehydrocarbonization tower 3 is connected to the inlet of the wastewater buffer tank 7 through the raw wastewater preheater 2.

[0026] Specifically, the wastewater buffer tank 7 serves to store and buffer wastewater, ensuring that the wastewater can enter the subsequent treatment process stably and evenly.

[0027] The inlet of the sewage transfer pump 8 is connected to the outlet of the sewage buffer tank 7, and the outlet of the sewage transfer pump 8 is connected to the inlet of the sulfur-containing sewage recooler 9 and the inlet of the ammonia-rich gas and sulfur-containing sewage heat exchanger 10, respectively.

[0028] Specifically, when the sewage reaches a certain level in the sewage buffer tank 7, the sewage transfer pump 8 starts to draw the sewage out of the sewage buffer tank 7. The sewage transfer pump 8 divides the sewage into two streams: one stream is sent to the sulfur-containing sewage recooler 9 for cooling treatment, and the other stream is sent to the ammonia-rich gas and sulfur-containing sewage heat exchanger 10.

[0029] After the outlet of the ammonia-rich gas heat exchanger 10 and the inlet of the sulfur-containing wastewater heat exchanger 11 are connected, they are connected to the wastewater stripping tower 12.

[0030] The reboiler 13 is connected to the wastewater stripping tower 12 to form a heat source circulation path, which is used to provide a heat source for the wastewater stripping tower 12.

[0031] The gas phase outlet of the wastewater stripping tower 12 is connected to the inlet of the separator 15 via the acid gas cooler 14. The upper gas phase outlet of the separator 15 is connected to the sulfur recovery system 21, and the lower liquid phase outlet of the separator 15 is connected to the fractionation tower reflux tank 22.

[0032] The inlet of the purified water pump 16 is connected to the liquid phase outlet of the sewage stripping tower 12, and the outlet of the purified water pump 16 is connected to the sulfur-containing sewage and purified water heat exchanger 11.

[0033] The ammonia gas extracted from the middle of the wastewater stripping tower 12 is transported to the ammonia-rich gas and sulfur-containing wastewater heat exchanger 10. After exchanging heat with the sulfur-containing ammonia wastewater, it is transported to the ammonia water recovery system 17.

[0034] Specifically, the ammonia recovery system 17 produces 10wt% ammonia.

[0035] Specifically, in the sulfur-containing wastewater and purified water heat exchanger 11, the sulfur-containing ammonia wastewater exchanges heat with the purified water from the bottom of the wastewater stripping tower 12. After further adjusting the temperature, the wastewater enters the wastewater stripping tower 12, and the treatment process in the wastewater stripping tower 12 is started.

[0036] After stripping, the gaseous material escapes from the gas outlet of the wastewater stripping tower 12. This gaseous material passes through an acid gas cooler 14, where it exchanges heat with a cooling medium, lowering its temperature. The cooled gaseous material then enters a separator 15 for gas-liquid separation, ensuring a purer output gaseous material and preparing it for subsequent processing, such as sending it to a sulfur recovery unit.

[0037] The inlets of both reboiler 6 and reboiler 13 are used to input low-pressure steam, and the outlets of both reboiler 6 and reboiler 13 are connected to the steam condensate pipeline network 18.

[0038] It should be noted that the two steam condensate pipe networks 18 have identical structures. One steam condensate pipe network 18 is connected to the reboiler 6, and the other steam condensate pipe network 18 is connected to the reboiler 13. Low-pressure steam is used as the heating medium, and the steam condensate pipe network 18 is used to drain the generated condensate.

[0039] Both the wastewater dehydrocarbon removal tower 3 and the wastewater stripping tower 12 adopt a plate tower structure.

[0040] The sewage booster pump 1, sewage transfer pump 8, and purified water pump 16 are all centrifugal pumps.

[0041] Specifically, centrifugal pumps can adjust their output pressure according to actual needs to meet the pressure requirements of various process stages.

[0042] This application also includes electric valves. The electric valves are installed at the outlets of the sewage booster pump 1, the sewage transfer pump 8, and the purified water pump 16.

[0043] The various embodiments in this specification are described in a progressive manner. For the same or similar parts between the various embodiments, please refer to each other. Each embodiment focuses on describing the differences from other embodiments.

[0044] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of this application.

Claims

1. A sulfur-containing ammonia wastewater treatment device, characterized in that, It includes a wastewater booster pump (1), a raw wastewater preheater (2), a wastewater dehydrogenation tower (3), a tower top condenser (4), a separator (5), a reboiler (6), a wastewater buffer tank (7), a wastewater transfer pump (8), a sulfur-containing wastewater recooler (9), an ammonia-rich gas and sulfur-containing wastewater heat exchanger (10), a sulfur-containing wastewater and purified water heat exchanger (11), a wastewater stripping tower (12), a reboiler (13), an acid gas cooler (14), a separator (15), and a purified water pump (16); The inlet of the sewage booster pump (1) is used to input sulfur-containing ammonia sewage, and the outlet of the sewage booster pump (1) is connected to the inlet of the raw sewage preheater (2). The outlet of the raw sewage preheater (2) is connected to the inlet of the sewage dehydrocarbonization tower (3). The gas phase outlet of the wastewater dehydrocarbon removal tower (3) is connected to the inlet of the top condenser (4), and the outlet of the top condenser (4) is connected to the separator (5). The reboiler (6) is connected to the wastewater dehydrogenation tower (3) to form a heat source circulation path, which is used to provide a heat source for the wastewater dehydrogenation tower (3); The liquid phase outlet of the wastewater dehydrocarbonization tower (3) is connected to the inlet of the wastewater buffer tank (7) through the raw wastewater preheater (2); The inlet of the sewage transfer pump (8) is connected to the outlet of the sewage buffer tank (7), and the outlet of the sewage transfer pump (8) is connected to the inlet of the sulfur-containing sewage recooler (9) and the ammonia-rich gas and sulfur-containing sewage heat exchanger (10), respectively. After the outlet of the ammonia-rich gas heat exchanger (10) and the inlet of the sulfur-containing wastewater heat exchanger (11) are connected, it is connected to the wastewater stripping tower (12). The reboiler (13) is connected to the wastewater stripping tower (12) to form a heat source circulation path, which is used to provide a heat source for the wastewater stripping tower (12); The gas phase outlet of the wastewater stripping tower (12) is connected to the inlet of the separator (15) through the acid gas cooler (14); The inlet of the purification water pump (16) is connected to the liquid phase outlet of the sewage stripping tower (12), and the outlet of the purification water pump (16) is connected to the sulfur-containing sewage and purification water heat exchanger (11). The ammonia gas extracted from the middle of the wastewater stripping tower (12) is transported to the ammonia-rich gas and sulfur-containing wastewater heat exchanger (10), where it exchanges heat with the sulfur-containing ammonia wastewater and is then transported to the ammonia water recovery system (17).

2. The sulfur-containing ammonia wastewater treatment device according to claim 1, characterized in that, The inlets of both the reboiler (6) and the reboiler (13) are used to input low-pressure steam, and the outlets of both the reboiler (6) and the reboiler (13) are connected to the steam condensate pipeline network (18).

3. The sulfur-containing ammonia wastewater treatment device according to claim 2, characterized in that, The upper gas phase outlet of the separator (5) is connected to the flare system (19), and the lower liquid phase outlet of the separator (5) is connected to the water-containing light oil storage tank (20). After the externally introduced nitrogen enters the separator (5), it enters the flare system (19) from the upper gas phase outlet of the separator (5).

4. The sulfur-containing ammonia wastewater treatment device according to claim 3, characterized in that, The upper gas phase outlet of the separator (15) is connected to the sulfur recovery system (21), and the lower liquid phase outlet of the separator (15) is connected to the fractionation tower reflux tank (22).

5. The sulfur-containing ammonia wastewater treatment device according to claim 4, characterized in that, Both the wastewater dehydrocarbon removal tower (3) and the wastewater stripping tower (12) adopt a plate tower structure.

6. The sulfur-containing ammonia wastewater treatment device according to claim 5, characterized in that, Centrifugal pumps are selected for the sewage booster pump (1), sewage transfer pump (8) and purified water pump (16).

7. The sulfur-containing ammonia wastewater treatment device according to claim 6, characterized in that, It also includes electric valves; Electric valves are installed at the outlets of the sewage booster pump (1), the sewage transfer pump (8), and the purified water pump (16).

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