A gasified black water vacuum flash treatment system

Abstract

The present invention discloses a vacuum flash treatment system for vaporized black water, comprising a vacuum flash evaporator, a gas phase pipe, a vacuum flash condenser, a vacuum flash separator, a gray water tank, a clarifier, and a condensation and impurity remover. The flash steam outlet of the vacuum flash evaporator is connected to the condensation and impurity remover via the gas phase pipe, and the gas outlet pipe of the condensation and impurity remover is directly connected to the gas inlet of the vacuum flash condenser via a pipeline. By arranging the condensation and impurity remover before the vacuum flash condenser, the present invention allows liquid with accumulated impurities to settle in advance, thereby reducing the impurity content in the gas entering the vacuum flash condenser, avoiding the blockage of the cooling pipe of the vacuum flash condenser by impurities, and improving the stability of the vaporized black water treatment system.

Description

Technical Field

[0001] The present invention relates to the technical field of coal gasification industry, and in particular to a gasified black water vacuum flash evaporation treatment system. Background Art

[0002] The gasifier in the coal chemical gasification section produces a large amount of black water with a relatively high temperature. Black water treatment requires high-pressure flash evaporation, low-pressure flash evaporation, and vacuum flash evaporation. Flash evaporation is used to remove acidic gases such as carbon dioxide and hydrogen sulfide from the black water.

[0003] Existing vacuum flash treatment system (please refer to Figure 6 ), the black water after low-pressure flash evaporation enters the vacuum flash evaporator 1 with a flash pressure of -0.052MPa and a flash temperature of 80℃ for flash evaporation. The gas (steam and acid gas) generated by flash evaporation enters the vacuum flash condenser 3 (shell-and-tube heat exchanger) along the gas phase pipe 2. The gas is cooled to 50 degrees through heat exchange in the vacuum flash condenser 3. The cooled gas enters the vacuum flash separator 4 to achieve gas-water separation. The condensate enters the ash water tank 5 along the bottom for storage, and the acidic non-condensable gas will be sent to the flare through a vacuum pump for combustion and discharge. The black water after flash evaporation in the vacuum flash evaporator 1 enters the clarification tank 6 through the bottom for clarification.

[0004] However, due to the complex water quality of black water, high hardness and soluble solid impurity content, tiny impurities (calcium and magnesium impurities) will enter the cooling tubes of the vacuum flash condenser 3 along with the gas phase. The solid content of the inlet gas of the vacuum flash condenser 3 detected by pipeline sampling is 0.2-0.3 mg / L. Since the numerous cooling tubes in the vacuum flash condenser 3 are relatively long (4-6m) and relatively thin (1-2cm) in diameter, these impurities will adhere to the cooling tubes. After long-term accumulation, these thin and long tubes will be blocked by impurities, affecting the heat exchange effect of the vacuum flash condenser 3 and reducing the operating efficiency of the black water vacuum flash evaporation system. Therefore, it is necessary to disassemble the vacuum flash condenser 3 and flush the tubes under high pressure. The disassembly, maintenance and flushing are not only performed at a high frequency of 2-3 months, but are also time-consuming and labor-intensive. In addition, the switching tube 21 needs to be used to cut out the vacuum flash condenser 3 during maintenance. This will cause the temperature in the vacuum flash separator 4 to be high without cooling the vacuum flash condenser 3, resulting in a high temperature in the ash water tank 5. These high-temperature ash waters are sent to the sewage treatment unit for treatment through the ash water pump 19, which requires additional cooling, and greatly increases energy consumption.

[0005] Therefore, there is still a need to improve the existing technology and propose more reasonable technical solutions to solve the above technical problems. Summary of the Invention

[0006] In order to solve the above problems, the purpose of the present invention is to provide a vacuum flash treatment system for vaporized black water which is energy-saving, not prone to clogging of the vacuum flash condenser, and has stable operation.

[0007] The present invention is achieved through the following technical solutions:

[0008] A gasified black water vacuum flash treatment system comprises a vacuum flash evaporator, a gas phase pipe, a vacuum flash condenser, a vacuum flash separator, an ash water tank, a clarifier, a condenser and impurity remover, an ash water pump, and a vacuum pump. The flash steam outlet of the vacuum flash evaporator is connected to the condenser and impurity remover by the gas phase pipe, and the gas outlet pipe of the condenser and impurity remover is directly connected to the gas inlet of the vacuum flash condenser by a pipeline; the vacuum flash evaporator outlet is connected to the clarifier through a pipeline, the upper outlet of the clarifier is connected to the ash water tank by a pipeline, and the lower outlet of the clarifier is connected to the inlet of a filter press; the outlet gas of the vacuum flash condenser is directly connected to the vacuum flash separator by a pipeline, the gas of the vacuum flash separator is sent to the torch via a vacuum pump, the liquid in the vacuum flash separator is sent to the ash water tank, and the liquid in the ash water tank is transported to a water treatment unit via the ash water pump.

[0009] Preferably, the lower outlet of the coagulation and impurity removal device is connected to the clarification tank via a settling pipe, a sewage pipe and a control valve.

[0010] Preferably, the condensation and impurity remover includes an installation box and a condensation box body installed in the installation box, the inlet of the installation box is connected to the guide pipe, the upper outlet of the installation box is connected to the air outlet pipe, and the lower outlet of the installation box is connected to the sedimentation pipe. After the condensation box body is installed, the installation box is divided into a condensation zone and a mixing zone. The condensation box body is located in the condensation zone, and the condensation zone is connected to the guide pipe. A baffle is arranged on the inner wall of the installation box between the air outlet pipe and the sedimentation pipe.

[0011] Preferably, a partition separates the condensation box into two cooling cavities, and a plurality of condensation tubes are arranged obliquely downward in the two cooling cavities in the condensation box, with outlets of the condensation tubes communicating with the mixing zone.

[0012] Preferably, the angle formed between the condensation tube and the horizontal plane is 30-60°.

[0013] Preferably, the inner diameter of the condensation tube is 3-5 cm, and the length of the condensation tube is in the range of 20-60.

[0014] Preferably, the cooling pipe inlet is connected to the liquid inlet of the condensation box through a pressure pump and a water supply pipe and further connected to the two cooling cavities. The outlets of the two cooling cavities are connected to the cooling pipe outlet through the liquid outlet of the condensation box and a drain pipe.

[0015] Preferably, a mounting cover is provided above the condensation box body, and the condensation box body is detachably mounted on the mounting box through the mounting cover plate.

[0016] Preferably, the condensation box further comprises a plurality of nozzles, which are arranged at the upper end of the mixing zone and are connected to the water supply pipe via a flushing pipe, a control valve and a branch pipe.

[0017] Compared with the existing technology, the beneficial effects of the present invention are:

[0018] The gasified black water vacuum flash treatment system of the present application sets a condenser and impurity remover in front of the vacuum flash condenser, so that the liquid with accumulated impurities is settled in advance, which greatly reduces the impurity content in the gas entering the vacuum flash condenser, avoids the blockage of impurities in the cooling pipe of the vacuum flash condenser, extends the frequency of maintenance and flushing of the vacuum flash condenser, maximizes the stability of the gasified black water treatment system, and also reduces the impurity content in the vacuum flash separator, ultimately reducing the gray water concentration in the gray water tank, reducing the load of subsequent water treatment, and reducing treatment energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic diagram of a gasified black water vacuum flash treatment system according to an embodiment of the present application;

[0020] Figure 2 This is a schematic structural diagram of a condensation impurity remover according to an embodiment;

[0021] Figure 3 yes Figure 2 Schematic diagram of the decomposition;

[0022] Figure 4 is a three-dimensional schematic diagram of a condensation box according to an embodiment;

[0023] Figure 5 is a cross-sectional view of a condensation box according to an embodiment;

[0024] Figure 6 It is a schematic diagram of a prior art gasification black water vacuum flash treatment system;

[0025] In the figure: vacuum flash evaporator 1, gas phase pipe 2, vacuum flash condenser 3, vacuum flash separator 4, ash water tank 5, clarification tank 6, guide pipe 7, condensation and impurity remover 8, mixing zone 81, installation box 9, sedimentation pipe 10, condensation box body 11, outer shell 111, partition 112, condensation pipe 113, liquid inlet 114, liquid outlet 115, installation cover 116, flushing pipe 117, nozzle 118, air outlet pipe 12, baffle 13, pressure pump 14, water supply pipe 15, branch pipe 151, drain pipe 16, cooling pipe 17, sewage pipe 18, ash water pump 19, vacuum pump 20, switching pipe 21. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0027] like Figure 1-Figure 5 As shown, the gasified black water vacuum flash treatment system of the present application includes a vacuum flash evaporator 1, a gas phase pipe 2, a vacuum flash condenser 3, a vacuum flash separator 4, an ash water tank 5, a clarifying tank 6, a condenser and impurity remover 8, an ash water pump 19, and a vacuum pump 20. The flash steam outlet of the vacuum flash evaporator 1 is connected to the condenser and impurity remover 8 by the gas phase pipe 2, and the gas outlet pipe 12 of the condenser and impurity remover 8 is directly connected to the gas inlet of the vacuum flash condenser 3 by a pipeline; the outlet of the vacuum flash evaporator 1 is connected to the clarifying tank 6 through a pipeline, the upper outlet of the clarifying tank 6 is connected to the ash water tank 5 by a pipeline, and the lower outlet of the clarifying tank 6 is connected to the inlet of the filter press; the outlet gas of the vacuum flash condenser 3 is directly connected to the vacuum flash separator 4 by a pipeline, the gas of the vacuum flash separator 4 is sent to the flare via the vacuum pump 20, the liquid in the vacuum flash separator 4 is sent to the ash water tank 5, and the liquid in the ash water tank 5 is transported to the water treatment unit via the ash water pump 19.

[0028] In one embodiment, the condensation impurity remover 8 includes an installation box 9 and a condensation box body 11 installed in the installation box 9, the inlet of the installation box 9 is connected to the guide pipe 7, the upper outlet of the installation box 9 is connected to the air outlet pipe 12, and the lower outlet of the installation box 9 is connected to the sedimentation pipe 10. After the condensation box body 11 is installed, the installation box (9) is divided into a condensation zone and a mixing zone 81. The condensation box body 11 is located in the condensation zone, which is connected to the guide pipe 7. The baffle 13 is arranged on the inner wall of the installation box 9 between the air outlet pipe 12 and the sedimentation pipe 10. All condensation pipes 113 are accommodated in the space surrounded by the shell 111. The partition 112 divides the condensation box body 11 into two cooling cavities. A plurality of condensation pipes 113 are arranged obliquely downward in the two cooling cavities in the condensation box body 11, and the outlets of the condensation pipes 113 are connected to the mixing zone 81.

[0029] In one embodiment, the angle between the baffle 13 and the horizontal line is 45° to 90°, more preferably 55° to 60°, and even more preferably 60°.

[0030] In one embodiment, the baffle 13 may have a conventional thickness in the art. Preferably, the minimum thickness of the baffle 13 is 26 mm.

[0031] In one embodiment, the surface of the baffle 13 is coated with chromium carbide. The thickness of the chromium carbide coating can be selected as needed, for example, within the range of 0.20-0.40 mm.

[0032] In one embodiment, the baffle 13 may be made of a conventional material in the art, preferably a highly wear-resistant material, and more preferably 316L stainless steel.

[0033] In one embodiment, the inlet of the cooling pipe 17 is connected to the liquid inlet 114 of the condensation box 11 through the pressure pump 14 and the water supply pipe 15, and further connected to the two cooling cavities. The outlets of the two cooling cavities are connected to the outlet of the cooling pipe 17 through the liquid outlet 115 and the drain pipe 16 of the condensation box 11; that is, the circulating water enters the left cooling cavity from the liquid inlet 114, exchanges heat with the left half of the condensation tube 113, then bypasses the partition 112 and continues to exchange heat with the right half of the condensation tube 113, and finally leaves the condensation box 11 through the liquid outlet 115. The provision of the partition 112 can increase the circulation time of the circulating water in the condensation box 11, thereby improving the cooling effect. In other embodiments, there can be multiple partitions 112.

[0034] In one embodiment, a mounting cover 116 is provided above the condensation box 11 , and the condensation box 11 is detachably mounted to the mounting box 9 via the mounting cover 116 .

[0035] In one embodiment, the coagulation tank 11 further includes a plurality of nozzles 118 . The nozzles 118 are disposed at the upper end of the mixing zone 81 . The nozzles 118 are connected to the water supply pipe 15 via a flushing pipe 117 , a control valve, and a branch pipe 151 .

[0036] The working principle or process of the gasified black water vacuum flash treatment system of this embodiment is described below:

[0037] The black water after low-pressure flash evaporation enters the vacuum flash evaporator 1 with a flash pressure of -0.052MPa and a flash temperature of 80°C. After negative pressure flash evaporation, the black water after flash evaporation is discharged along the bottom pipe of the vacuum flash evaporator 1 to the clarification tank 6 for clarification treatment. The supernatant clarified in the clarification tank 6 overflows to the gray water tank 5 through the pipeline for storage, and the impurities deposited at the bottom of the clarification tank 6 are discharged to the filter press through the lower outlet for treatment; the gas formed after flash evaporation is transported to the condensation and impurity remover 8 along the gas phase pipe 2 at the top of the vacuum flash evaporator 1. When entering the condensation and impurity remover 8, it first passes through the inclined condensation pipe 113 of the condensation box 11, and exchanges heat with the liquid circulating in the condensation box 11 to reduce the temperature in the gas. Part of the steam will condense into liquid, which will adsorb the tiny particle impurities in the flash steam to the surface of the water droplets to achieve aggregation and impurity removal. The liquid that adsorbs impurities and the acidic non-condensable gas are discharged along the inclined The condensation tube 113 moves toward the baffle 13 facing it. After being blocked by the baffle 13, the liquids with accumulated impurities will fall along the sedimentation tube 10 under the action of gravity and gather to form impurity-containing sewage. After the sewage accumulated in the sedimentation tube 10 has accumulated for a certain period of time, the sewage in the sedimentation tube 10 is discharged into the clarification tank 6 by opening the control valve on the sewage pipe 18. This greatly reduces the content of impurities in the gas entering the vacuum flash condenser 3, avoids the blockage of impurities in the cooling tube 17 of the vacuum flash condenser 3, and extends the frequency of maintenance and flushing of the vacuum flash condenser 3 from the previous flushing every 2-3 months to every 8-10 months, thereby maximizing the stability of the gasification black water treatment system and reducing the impurity content in the vacuum flash separator 4, thereby ultimately reducing the gray water concentration in the gray water tank 5 and reducing the load of subsequent water treatment.

[0038] The non-condensable acid gas and the uncondensed steam will continue to enter the vacuum flash condenser 3 along the outlet pipe 12 and exchange heat with the cooling circulating water of the cooling pipe 17. The outlet temperature is 40-45 degrees Celsius. At this time, the inlet solid content of the empty flash condenser 3 is detected to be 0.05-0.1 mg / L. The gas and condensed water after heat exchange enter the vacuum flash separator 4. The condensed water will gather downward and finally be transported to the ash water tank 5 for storage. The liquid in the ash water tank 5 is transported to the water treatment unit for treatment through the ash water pump 19, and the acidic non-condensable gas entering the vacuum flash separator 4 is extracted by the vacuum pump 20 and sent to the flare for combustion and discharge.

[0039] After the cooling circulating water in the cooling pipe 17 exchanges heat with the non-condensable acid gas and the non-condensable steam in the vacuum flash condenser 3 , the temperature of the cooling circulating water increases and the cooling circulating water is discharged through the drain pipe 16 or continues to be recycled.

[0040] The condensation chamber 11 has several condensation tubes 113 arranged downwardly at an angle of 30-60 degrees. Flash gas flows along the inclined condensation tubes 113 into the mixing zone 81 for mixing. The inclined condensation tubes 113 cause the gas to impact the baffle 13. After rapidly impacting the baffle 13, the gas diffuses back toward the mixing zone 81, resulting in a more uniform mixing of the water droplets and unabsorbed micro-impurities. This maximizes the adsorption effect of the water droplets on the unabsorbed micro-impurities, significantly reducing the impurity content in the gas entering the outlet pipe 12. A guide pipe 7 is provided at the front end of the inlet of the condensation and impurity remover 8, aligned with the direction of the condensation tubes 113, to provide better flow stability for the gas entering the guide pipe 7. The outlets of the multiple condensation tubes 113 of the condensation chamber 11 are arranged as an inclined surface, providing the mixing zone 81 with a larger mixing space, ensuring a better mixing effect. The diameter of the condensation tube 113 is set to 3-5 cm, and the length range is between 20-60 to ensure gas permeability and avoid impurities clogging the condensation tube 113.

[0041] The cooling water of the condensation box 11 is supplied by the pressure pump 14, and the liquid in the inlet part of the cooling pipe 17 of the vacuum flash condenser 3 is pressurized and sent to the condensation box 11 along the water supply pipe 15 through the liquid inlet 114, and then passes through the two cooling cavities separated by the partition 112 in the condensation box 11 in turn, and finally is sent to the outlet of the cooling pipe 17 along the liquid outlet 115 and the drain pipe 16 for circulation.

[0042] When the condensate remover 8 has a long service life, the control valve of the branch pipe 151 on the water supply pipe 15 can be opened, and high-pressure water enters the flushing pipe 117 along the branch pipe 151, and is sprayed from each nozzle 118 to flush the mixing area 81, so that the impurities deposited in the mixing area 81 are flushed online to avoid clogging of the mixing area 81. At the same time, when the system is stopped, the bolts on the mounting cover 116 of the condensate box 11 can be removed. After removal, the condensate box 11 is taken out, and the condensate pipe 113 and the interior of the condensate remover 8 are completely cleaned to ensure the subsequent operation stability of the condensate remover 8.

[0043] Flash evaporation principle: When a high-pressure, saturated liquid enters a relatively low-pressure container, the sudden drop in pressure causes it to transform into a portion of saturated vapor and liquid at the container's pressure. The boiling point of a substance increases with increasing pressure, while the lower the pressure, the lower the boiling point. This allows the high-pressure, high-temperature fluid to undergo decompression, lowering its boiling point. Upon entering the flash tank, where the fluid temperature is higher than its boiling point at that pressure, it rapidly boils and vaporizes, and the two phases separate. Flash evaporation does not require heating.

[0044] The key equipment of the gasified black water vacuum flash treatment system of the present application is the condenser and impurity remover. The angle between the baffle and the horizontal line and the angle between the condensation pipe and the horizontal line in the condenser and impurity remover will affect the pipeline of the vacuum flash condenser, that is, the stable operation cycle. The results are shown in Table 1 below.

[0045] Table 1

[0046] Table 1 shows that changing the angle between the baffle and the horizontal line or the condenser tube in the condensate remover can affect the scaling of the cooling tubes in the vacuum flash condenser and also affect the stable operation cycle. As shown in the table above, setting the angle between the baffle and the horizontal line and the condenser tube to the horizontal line at appropriate angles can reduce pipe scaling and increase the stable operation cycle of the vacuum flash condenser.

[0047] The gasified black water vacuum flash treatment system of the present application sets a condenser and impurity remover in front of the vacuum flash condenser 3, so that the liquid with accumulated impurities is settled in advance, which greatly reduces the impurity content in the gas entering the vacuum flash condenser 3, avoids the blockage of impurities in the cooling pipe 17 of the vacuum flash condenser 3, extends the frequency of maintenance and flushing of the vacuum flash condenser 3, maximizes the stability of the gasified black water treatment system, and also reduces the impurity content in the vacuum flash separator 4, ultimately reducing the gray water concentration in the gray water tank 5, reducing the load of subsequent water treatment, and reducing treatment energy consumption.

[0048] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A gasified black water vacuum flash treatment system, comprising a vacuum flash evaporator (1), a gas phase pipe (2), a vacuum flash condenser (3), a vacuum flash separator (4), an ash water tank (5), a clarifier (6), a condensation and impurity removal device (8), an ash water pump (19), and a vacuum pump (20), characterized in that: The flash steam outlet of the vacuum flash evaporator (1) is connected to the condenser and impurity remover (8) via the gas phase pipe (2), and the gas outlet pipe (12) of the condenser and impurity remover (8) is directly connected to the gas inlet of the vacuum flash condenser (3) via a pipeline; the outlet of the vacuum flash evaporator (1) is connected to the clarifier (6) via a pipeline, the upper outlet of the clarifier (6) is connected to the ash water tank (5) via a pipeline, and the lower outlet of the clarifier (6) is connected to the inlet of the filter press; the outlet gas of the vacuum flash condenser (3) is directly connected to the vacuum flash separator (4) via a pipeline, the gas of the vacuum flash separator (4) is sent to the flare via a vacuum pump (20), and the liquid in the vacuum flash separator (4) is sent to the ash water tank (5), and the liquid in the ash water tank (5) is transported to the water treatment unit via the ash water pump (19); The condensation and impurity remover (8) includes an installation box (9) and a condensation box body (11) installed in the installation box (9), the inlet of the installation box (9) is connected to the guide pipe (7), the upper outlet of the installation box (9) is connected to the air outlet pipe (12), and the lower outlet of the installation box (9) is connected to the sedimentation pipe (10). After the condensation box body (11) is installed, the installation box (9) is divided into a condensation zone and a mixing zone (81), the condensation box body (11) is located in the condensation zone, and the condensation zone is connected to the guide pipe (7). A baffle (13) is arranged on the inner wall of the installation box (9) between the air outlet pipe (12) and the sedimentation pipe (10).

2. A vacuum flash evaporation treatment system for gasified black water according to claim 1, characterized in that: The lower outlet of the condensation and impurity remover (8) is connected to the clarification tank (6) via a sedimentation pipe (10), a sewage pipe (18) and a control valve.

3. A vacuum flash evaporation treatment system for gasified black water according to claim 1, characterized in that: A partition (112) divides the condensation box (11) into two cooling cavities. A plurality of condensation tubes (113) are arranged obliquely downward in the two cooling cavities in the condensation box (11). The outlets of the condensation tubes (113) are connected to the mixing zone (81).

4. A vacuum flash evaporation treatment system for gasified black water according to claim 3, characterized in that: The outlet end surfaces of the plurality of condensation tubes (113) are integrally configured as inclined surfaces.

5. A vacuum flash evaporation treatment system for gasified black water according to claim 4, characterized in that: The angle formed between the condensation tube (113) and the horizontal plane is 30-60°.

6. A vacuum flash evaporation treatment system for gasified black water according to claim 5, characterized in that: The inner diameter of the condensation tube (113) is 3-5 cm, and the length of the condensation tube (113) is in the range of 20-60 cm.

7. A vacuum flash evaporation treatment system for gasified black water according to claim 3, characterized in that: The inlet of the cooling pipe (17) is opened sideways and connected to the liquid inlet of the pressure pump (14), the water supply pipe (15) and the condensation box (11). (114) is connected and further connected to the two cooling cavities, and the outlets of the two cooling cavities are merged into the outlet of the cooling pipe (17) through the liquid outlet (115) and the drain pipe (16) of the condensation box (11).

8. A vacuum flash evaporation treatment system for gasified black water according to claim 7, characterized in that: A mounting cover plate (116) is provided above the condensation box body (11), and the condensation box body (11) is detachably mounted on the mounting box (9) via the mounting cover plate (116).

9. A gasified black water vacuum flash treatment system according to any one of claim 3, characterized in that: The condensation box (11) further comprises a plurality of nozzles (118), which are arranged at the upper end of the mixing zone (81) and are connected to the water supply pipe (15) via a flushing pipe (117), a control valve, and a branch pipe (151).

Images