An energy-saving device for preparing industrial steam using waste hot water

Abstract

An energy-saving device for preparing industrial steam using waste hot water belongs to the field of waste heat utilization technology. It includes a vacuum flash separation tank, a screw steam extraction compressor, and a screw steam supercharger. The vacuum flash separation tank includes a steam-water separation chamber and an evaporation chamber. The waste hot water enters the evaporation chamber for flash evaporation, and the low-pressure water vapor from the flash evaporation enters the screw steam extraction compressor. The screw steam extraction compressor sucks the evaporation chamber into a negative pressure; the waste hot water after flash evaporation and cooling is discharged; the steam discharged from the screw steam extraction compressor enters the screw steam supercharger to further pressurize it to the pressure required by the customer, and the pressurized steam-water mixture discharged from the screw steam supercharger returns to the steam-water separation chamber, and the steam-water separation chamber separates the pressurized steam-water mixture; the separated steam is supplied to the customer, and the separated condensed water returns to the evaporation chamber. Advantages: high steam preparation temperature, simple system, short investment recovery period, can be applied to industries with large amounts of waste hot water and industrial steam demand.

Description

Technical Field

[0001] The invention belongs to the technical field of waste heat utilization, and specifically relates to an energy-saving device for preparing industrial steam by utilizing waste hot water. Background Art

[0002] Industrial steam is an important secondary energy source in my country, and is widely used in petrochemical, steel, textile, food, medical, environmental protection and other industries, playing the role of driving, heating, evaporation, drying, disinfection, etc. At present, my country's industrial steam is mainly produced by coal-fired boilers, with low preparation costs, but the resulting pollution and greenhouse effect are serious, especially small and medium-sized coal-fired boilers are in the process of accelerated elimination. In the field of industrial steam preparation, coal-to-electricity has become a major trend at present.

[0003] The simplest way to prepare industrial steam using electricity is to directly use electricity to heat hot water to generate steam. The principle is simple, the investment is small, but the power consumption is high. A more energy-saving way is to use the heat pump principle to extract heat from the environment or waste heat, generate hot water for flash evaporation, and then use a steam compressor to increase the pressure for steam preparation.

[0004] Compared with heat extraction from the environment and waste heat, the waste heat has a higher temperature, lower energy consumption for steam preparation, and a shorter investment payback period. Especially in the petrochemical, textile, food, environmental protection and other industrial equipment, a large amount of waste hot water is generated during operation, and the waste heat utilization value is extremely high.

[0005] In order to utilize the waste heat of waste hot water for steam preparation, the following three patented technologies are introduced:

[0006] For example, the Chinese invention patent application publication number CN105674627A discloses a "water source heat pump driven water vapor modulator", which includes a system integrated circulation pump, a water source heat pump, a throttle valve, a nozzle, a flash tank, and a nozzle injection and expansion device; the water source heat pump is used to heat the circulating water to provide flash heat; the circulating heating, throttling, spraying, and flashing are used to continuously generate secondary steam; the residual pressure of the steam pipe network is used to achieve the thermal compression of the secondary steam, saving the electricity cost and investment of the water vapor compressor. However, the disadvantage of this technical solution is that although natural water is used as the working medium of the entire heat pump system, in order to have the trigeneration function, the system is equipped with evaporators, gas storage tanks, circulation pumps, condensers, liquid storage tanks, mixing tanks and other dynamic and static equipment, which increases the initial investment cost and complexity of the system.

[0007] For another example, the "water working medium heat pump system for trigeneration of low-pressure steam, high-pressure steam and high-temperature hot water" disclosed in the Chinese invention patent application publication number CN110186219A includes a low-grade waste heat recovery heat pump subsystem using water working medium and a steam hot water trigeneration subsystem. By using a high-pressure compressor, a high-pressure control valve and a high-pressure liquid injection pipe, the low-pressure steam is compressed into high-pressure steam, effectively meeting the user's demand for high-pressure steam. However, the disadvantages of this technology are: the pressure-raising equipment needs to use a nozzle-injected diffuser to raise the pressure of the secondary steam, and the nozzle-injected diffuser requires high-pressure steam as a driving source. Once the client does not have enough high-pressure steam, steam preparation cannot be achieved; the patent uses refrigerant to recover waste heat, and the system must be equipped with necessary evaporators, condensers, circulating pumps and other dynamic and static equipment, which increases the initial investment cost and complexity of the system.

[0008] For another example, the Chinese invention patent application publication number CN111595063A discloses a "wastewater source steam compression dry heat pump unit", which allows industrial wastewater to directly enter the evaporator and then flash evaporate, so that the wastewater that is originally highly corrosive and prone to scaling and clogging is converted into clean steam, and then the heat is transferred out through the flash steam, thereby achieving efficient and clean utilization of industrial wastewater. However, the disadvantages of this technology are: in order to adapt to the characteristics of the wastewater source, a complex evaporator is designed to achieve waste heat recovery and utilization of medium and low temperature industrial wastewater containing a large amount of soluble solids, such as for hot water recovery with high cleanliness, and the initial investment cost is high; the patent uses Freon to recover waste heat, which inevitably increases the complexity of the system.

[0009] In view of the shortcomings of the current process of using waste hot water to prepare steam, such as low steam preparation temperature, complex system, and long investment recovery period, it is necessary to reasonably improve the structure of the existing energy-saving device for preparing industrial steam using waste hot water. To this end, the applicant has made a useful design, and the technical solution to be introduced below is produced under this background. Summary of the invention

[0010] The task of the present invention is to provide an energy-saving device for preparing industrial steam using waste hot water. By introducing waste hot water into a vacuum flash separation tank, a screw steam compressor is used to pump and pressurize the vacuum flash separation tank to the pressure required by the user. It has the advantages of high steam preparation temperature, simple system, and short investment recovery period. It can be widely used in industries such as petrochemical, textile, food, and environmental protection that generate a large amount of waste hot water and have industrial steam needs.

[0011] The task of the present invention is accomplished in this way: an energy-saving device for preparing industrial steam using waste hot water comprises a vacuum flash separation tank, a screw steam extraction compressor and a screw steam supercharger, wherein the vacuum flash separation tank comprises a steam-water separation chamber and an evaporation chamber, waste hot water enters the evaporation chamber for flash evaporation, low-pressure water vapor flashed in the evaporation chamber enters the screw steam extraction compressor, and the screw steam extraction compressor sucks the evaporation chamber into a negative pressure; the steam discharged from the screw steam extraction compressor enters the screw steam supercharger for further pressurization to the pressure required by the customer, the pressurized steam-water mixture discharged from the screw steam supercharger returns to the steam-water separation chamber of the vacuum flash separation tank, and the steam-water separation chamber performs steam-water separation on the pressurized steam-water mixture; the steam separated by the steam-water separation chamber is supplied to the customer, and the condensed water separated by the steam-water separation chamber returns to the evaporation chamber, and the characteristics are:

[0012] The evaporation chamber is equipped with a liquid level sensor with a remote transmission function. When the liquid level sensor shows that the liquid level in the evaporation chamber has reached the set value, the water pump is started, and the waste hot water after flash evaporation and cooling enters the water pump through the water outlet pipe 1. The waste hot water after being pressurized by the water pump is discharged through the water pump outlet pipe. A part of the waste hot water discharged through the water pump outlet pipe continues to be discharged, and a part enters the screw steam extraction compressor through the water outlet pipe 3, the throttling orifice plate and the water outlet pipe 4, thereby realizing the cooling of the screw steam extraction compressor.

[0013] In a specific embodiment of the present invention, the vacuum flash separation tank further comprises a shell and a partition. The inner cavity of the shell comprises the steam-water separation chamber and the evaporation chamber. A partition is arranged between the steam-water separation chamber and the evaporation chamber.

[0014] In another specific embodiment of the present invention, the vacuum flash separation tank further comprises a wire mesh demister, and the wire mesh demister is arranged in the steam-water separation chamber and is used for filtering the saturated steam separated from the steam-water separation chamber.

[0015] In another specific embodiment of the present invention, the vacuum flash separation tank further comprises a nozzle, and the waste hot water enters the vacuum flash separation tank through the water inlet pipe after entering the waste hot water inlet, and enters the evaporation chamber for flash evaporation after being atomized by the nozzle.

[0016] In a further specific embodiment of the present invention, the waste hot water is pressurized by a water pump and then enters a drainage control valve through an outlet pipe of the water pump, and is then discharged through a second outlet pipe.

[0017] In yet another specific embodiment of the present invention, a pressure sensor with remote transmission function is installed on the compressor outlet pipe of the screw steam extraction compressor, and the screw steam extraction compressor adopts variable frequency regulation to control the outlet pressure displayed by the pressure sensor to the required set value.

[0018] In yet another specific embodiment of the present invention, a pressure sensor 2 with a remote transmission function is installed on the compressor outlet pipe of the screw steam booster, and the screw steam booster adopts variable frequency regulation to control the outlet pressure displayed by the pressure sensor 2 to the required set value.

[0019] The present invention has the beneficial effects of adopting the above structure: in the energy-saving device, waste hot water directly enters the vacuum flash separation tank to flash out low-pressure steam, and generates high-pressure steam by adopting a combination of a screw steam extraction compressor and a screw steam booster, and then returns to the vacuum flash separation tank for steam-water separation, which has the following advantages:

[0020] (1) A screw steam extraction compressor is used to maintain a low saturated steam temperature (50°C or lower) in the vacuum flash separation tank. There is no need for the refrigerant system to absorb heat, which reduces the heat transfer link. At the same time, the vacuum flash separation tank inherits the steam-water separation function, avoiding the shortcomings of the public patents "CN105674627 A", "CN110186219 A", and "CN111595063 A" in terms of complex systems and high investment costs;

[0021] (2) A screw steam booster is used to increase the pressure and directly produce high-temperature steam (1 MPaA or higher), which avoids the disadvantage of the patent "CN 110186219 A" that requires high-pressure steam as a driving source and has a wide range of applications.

[0022] (3) The main equipment configured in this system is only a screw steam extraction compressor, a screw steam booster and a vacuum flash separation tank. There is no need for large-scale dynamic and static equipment such as condensers, evaporators, and circulating pumps. At the same time, water is used as the working fluid, which saves the purchase cost of the refrigerant system. It has the advantages of high steam preparation temperature, simple system, and short investment recovery period. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic structural diagram of an embodiment of an energy-saving device for preparing industrial steam using waste hot water according to the present invention.

[0024] In the figure: 1. water inlet pipe; 2. vacuum flash separation tank, 201. shell, 202. wire mesh demister, 203. steam-water separation chamber, 204. partition, 205. evaporation chamber, 206. nozzle; 3. air inlet pipe; 4. screw extraction steam compressor; 5. compressor outlet pipe; 6. screw steam booster; 7. booster outlet pipe; 8. exhaust pipe; 9. water outlet pipe 1; 10. water pump; 11. water pump outlet pipe; 12. control valve; 13. water outlet pipe 2; 14. water outlet pipe 3; 15. throttling orifice; 16. water outlet pipe 4; 17. condensate pipe 1; 18. steam trap; 19. condensate pipe 2; 20. pressure sensor 1; 21. pressure sensor 2; 22. liquid level sensor. DETAILED DESCRIPTION

[0025] The following is a detailed description in the form of embodiments in combination with the accompanying drawings, but the description of the embodiments is not a limitation on the technical solution of the present invention. Any equivalent changes made based on the concept of the present invention that are merely formal but not substantial should be regarded as within the scope of the technical solution of the present invention.

[0026] In the following description, all concepts related to up, down, left, right, front and back directions or orientations are based on Figure 1 The positions shown are for reference only and thus cannot be understood as a special limitation on the technical solution provided by the present invention.

[0027] See also Figure 1 The present invention relates to an energy-saving device for preparing industrial steam by utilizing waste hot water, comprising a vacuum flash separation tank 2, a screw steam extraction compressor 4, and a screw steam supercharger 6. The vacuum flash separation tank 2 comprises a steam-water separation chamber 203 and an evaporation chamber 205. The waste hot water enters the evaporation chamber 205 for flash evaporation, and the low-pressure water vapor flashed in the evaporation chamber 205 enters the screw steam extraction compressor 4, and the screw steam extraction compressor 4 sucks the evaporation chamber 205 into a negative pressure; the waste hot water after flash evaporation and cooling is discharged; the steam discharged from the screw steam extraction compressor 4 enters the screw steam supercharger 6 for further pressurization to the pressure required by the customer, and the steam-water mixture discharged from the screw steam supercharger 6 returns to the steam-water separation chamber 203 of the vacuum flash separation tank 2, and the steam-water separation chamber 203 performs steam-water separation on the pressurized steam-water mixture; the saturated steam separated by the steam-water separation chamber 203 is supplied to the customer, and the condensed water separated by the steam-water separation chamber 203 returns to the evaporation chamber 205.

[0028] The vacuum flash separation tank 2 further comprises a shell 201, a wire mesh demister 202, a partition 204 and a nozzle 206. The inner cavity of the shell 201 comprises the steam-water separation chamber 203 and the evaporation chamber 205. A partition 204 is arranged between the steam-water separation chamber 203 and the evaporation chamber 205. The lower side of the steam-water separation chamber 203 is the partition 204, and the upper side is the wire mesh demister 202, which is used to filter the saturated steam separated from the steam-water separation chamber 203. The evaporation chamber 205 is located at the lower layer of the shell 201.

[0029] After entering the waste hot water inlet, the waste hot water enters the vacuum flash separation tank 2 through the water inlet pipe 1, and enters the evaporation chamber 205 for flash evaporation after being atomized by the nozzle 206. The evaporation chamber 205 is equipped with a liquid level sensor 22 with a remote transmission function. When the liquid level sensor 22 shows that the liquid level of the evaporation chamber 205 has reached the set value, the water pump 10 is started, and the waste hot water after flash evaporation and cooling enters the water pump 10 through the outlet pipe 19. After the waste hot water is pressurized by the water pump 10, it enters the drainage control valve 12 through the water pump outlet pipe 11, and then is discharged from the outlet pipe 2 13. At the same time, a small amount of waste hot water after flash evaporation and cooling enters the screw steam extraction compressor 4 through the outlet pipe 3 14, the throttling orifice plate 15 and the outlet pipe 4 16. Here, the liquid level signal of the evaporation chamber 205 is transmitted to the drainage control valve 12 by the liquid level sensor 22 for control.

[0030] After starting the water pump 10, the screw steam extraction compressor 4 and the screw steam booster 6 are immediately started. Under the suction action of the screw steam extraction compressor 4, the pressure in the evaporation chamber 205 gradually decreases until low-pressure steam is flashed out.

[0031] The low-pressure water vapor flashed out in the evaporation chamber 205 enters the screw steam extraction compressor 4 through the air inlet pipe 3. That is, the screw steam extraction compressor 4 is used to pump the evaporation chamber 205 into a negative pressure, so that the waste hot water can be evaporated at a temperature of 50°C or lower, so as to fully utilize the waste heat of the waste hot water. The screw steam extraction compressor 4 adopts water spray cooling, and the maximum pressure ratio can reach 10 or higher, so that the outlet steam pressure of the screw steam extraction compressor 4 is close to or exceeds the atmospheric pressure.

[0032] The cooling water required for the screw steam extraction compressor 4 is the waste hot water after flash evaporation and cooling, which is divided from the water pump outlet pipe 11 and provided by the outlet pipe 3 14, the throttling orifice plate 15 and the outlet pipe 4 16. The compressor outlet pipe 5 of the screw steam extraction compressor 4 is equipped with a pressure sensor 20 with a remote transmission function. The screw steam extraction compressor 4 adopts variable frequency regulation to control the outlet pressure displayed by the pressure sensor 20 to the required set value.

[0033] The steam discharged from the screw steam compressor 4 enters the screw steam booster 6 through the compressor outlet pipe 5 and is further pressurized to the pressure required by the customer. The steam-water mixture discharged from the screw steam booster 6 through the booster outlet pipe 7 returns to the steam-water separation chamber 203 of the vacuum flash separation tank 2, and the steam-water separation chamber 203 separates the pressurized steam-water mixture. The saturated steam separated by the steam-water separation chamber 203 is filtered by the wire mesh demister 202 and then supplied to the customer through the exhaust pipe 8; and the separated condensed water returns to the evaporation chamber 205 through the condensed water pipe 1 17, the steam trap 18 and the condensed water pipe 2 19, so as to fully utilize the waste heat of the condensed water.

[0034] The screw steam booster 6 is cooled by water spraying, and the maximum pressure ratio can reach 10 or higher, so the outlet pressure of the screw steam booster 6 can reach 1.0 MPaA or higher, meeting the needs of general industrial steam users. The booster outlet pipe 7 of the screw steam booster 6 is equipped with a pressure sensor 21 with a remote transmission function, and the screw steam booster 6 adopts variable frequency regulation to control the outlet pressure displayed by the pressure sensor 21 to the required set value.

Claims

1. An energy-saving device for preparing industrial steam using waste hot water, comprising a vacuum flash separation tank (2), a screw steam extraction compressor (4), and a screw steam booster (6), wherein the vacuum flash separation tank (2) comprises a steam-water separation chamber (203) and an evaporation chamber (205), the waste hot water enters the evaporation chamber (205) for flash evaporation, the low-pressure water vapor flashed out in the evaporation chamber (205) enters the screw steam extraction compressor (4), and the screw steam extraction compressor (4) sucks the evaporation chamber (205) into a negative pressure; the screw steam extraction compressor (4) The steam discharged from the steam compressor (4) enters the screw steam supercharger (6) to be further pressurized to the pressure required by the customer. The pressurized steam-water mixture discharged from the screw steam supercharger (6) is returned to the steam-water separation chamber (203) of the vacuum flash separation tank (2), and the steam-water separation chamber (203) separates the pressurized steam-water mixture into steam and water; the steam separated by the steam-water separation chamber (203) is supplied to the customer, and the condensed water separated by the steam-water separation chamber (203) is returned to the evaporation chamber (205), characterized in that: The evaporation chamber (205) is equipped with a liquid level sensor (22) with a remote transmission function. When the liquid level sensor (22) indicates that the liquid level in the evaporation chamber (205) has reached a set value, the water pump (10) is started, and the waste hot water after flash evaporation and cooling enters the water pump (10) through the water outlet pipe (9). The waste hot water after pressurization by the water pump (10) is discharged through the water pump outlet pipe (11). A part of the waste hot water discharged through the water pump outlet pipe (11) continues to be discharged, and a part enters the screw steam extraction compressor (4) through the water outlet pipe (14), the throttling orifice plate (15) and the water outlet pipe (16), thereby cooling the screw steam extraction compressor (4).

2. The energy-saving device for preparing industrial steam using waste hot water according to claim 1, characterized in that The vacuum flash separation tank (2) further comprises a shell (201) and a partition (204); the inner cavity of the shell (201) comprises the steam-water separation chamber (203) and the evaporation chamber (205); and a partition (204) is provided between the steam-water separation chamber (203) and the evaporation chamber (205).

3. The energy-saving device for preparing industrial steam using waste hot water according to claim 2, characterized in that The vacuum flash separation tank (2) further comprises a wire mesh demister (202), wherein the wire mesh demister (202) is arranged in the steam-water separation chamber (203) and is used for filtering the saturated steam separated in the steam-water separation chamber (203).

4. The energy-saving device for preparing industrial steam using waste hot water according to claim 2, characterized in that The vacuum flash separation tank (2) further comprises a nozzle (206). After the waste hot water enters from the waste hot water inlet, it enters the vacuum flash separation tank (2) through the water inlet pipe (1), and after being atomized by the nozzle (206), it enters the evaporation chamber (205) for flash evaporation.

5. The energy-saving device for preparing industrial steam using waste hot water according to claim 1, characterized in that The waste hot water is pressurized by the water pump (10) and enters the drainage control valve (12) through the water pump outlet pipe (11), and is then discharged through the second water outlet pipe (13).

6. The energy-saving device for preparing industrial steam using waste hot water according to claim 1, characterized in that A pressure sensor (20) with a remote transmission function is installed on the compressor outlet pipe (5) of the screw steam extraction compressor (4). The screw steam extraction compressor (4) adopts variable frequency regulation to control the outlet pressure displayed by the pressure sensor (20) to a required set value.

7. The energy-saving device for preparing industrial steam using waste hot water according to claim 1, characterized in that A second pressure sensor (21) with a remote transmission function is installed on the compressor outlet pipe (7) of the screw steam compressor (6). The screw steam compressor (6) adopts variable frequency regulation to control the outlet pressure displayed by the second pressure sensor (21) to a required set value.

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