System for producing low-pressure steam and process circulating hot water through heat energy recovery
By converting the heat of exhausted steam and circulating cooling water in the high-temperature and low-temperature refrigerant system step by step, the problem of low heat recovery efficiency in the yellow phosphorus production process is solved, and the effective recycling of low-pressure steam and high-temperature hot water is achieved, reducing environmental pollution and production energy consumption.
Patent Information
- Application Number
- CN202421745128.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-23
- Publication Date
- 2025-07-25
- Estimated Expiration
- 2034-07-23
AI Technical Summary
The prior art is difficult to effectively recover the heat energy of the slag flushing water in the production process of yellow phosphorus and the condensation cooling water of the circulating cooling water of the phosphorus furnace gas, resulting in environmental pollution and energy waste.
The high-temperature and low-temperature refrigerant system is adopted to convert the heat runners of the exhausted steam and circulating cooling water into low-pressure steam and high-temperature hot water through the heat pump principle. The energy conversion is carried out using screw compressors and heat exchangers to reduce the consumption of circulating cooling water and improve energy conversion efficiency.
It realizes effective recycling of low-pressure steam and high-temperature hot water, reduces environmental pollution and production energy consumption, improves energy utilization efficiency, and reduces production costs.
Smart Images
Figure CN223154029U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a slag flushing water exhaust steam recovery combined with phosphorous furnace gas condensation and recycled cooling water heat energy recovery to produce low-pressure steam and process circulating hot water system in a yellow phosphorus production process, belonging to the technical field of using a heat pump system to convert low-grade heat energy into medium-grade heat energy to achieve energy conservation and emission reduction. Background Art
[0002] During the production of yellow phosphorus in a yellow phosphorus electric furnace, a large amount of molten slag is generated. The molten slag is cooled by water quenching. Due to the high temperature of the molten slag, during water quenching, the slag flushing water vaporizes due to rapid heat exchange. The vaporized water vapor pollutes the environment and also takes away a large amount of heat energy. By adopting the solution proposed in this patent, the heat energy of the exhaust steam is recovered through a high-temperature refrigerant and conducted to high-temperature hot water to flash out low-pressure steam for use in the plant process equipment. Thereby, environmental pollution is reduced and the heat energy is recycled for use in the equipment, achieving the purpose of energy conservation and emission reduction.
[0003] In the cooling process of the phosphorous furnace gas in the yellow phosphorus production device, it needs to directly exchange heat with the recycled cooling water. Since the phosphorous furnace gas has a high sensible heat and the latent heat of phosphorus liquefaction, the recycled cooling water after heat exchange has a high temperature. Moreover, since the recycled cooling water is in direct contact with the phosphorous furnace gas, phosphorus and other harmful impurities will enter the recycled cooling water system. When cooled by a cooling tower, the impurities will escape into the atmospheric environment, causing atmospheric environmental pollution. Here, the solution proposed in this patent is also adopted. The phosphorus-containing high-temperature recycled cooling water is cooled through the technology of vacuum flashing. The flashed water vapor exchanges heat and condenses with a low-temperature refrigerant. The refrigerant vaporizes and is compressed, and then exchanges heat with the hot water circulating in the plant to recover the heat energy of the phosphorus-containing high-temperature recycled cooling water, also achieving the purpose of energy conservation and emission reduction.
[0004] At present, there are the following common forms for the recovery of exhaust steam or recycled cooling water waste heat:
[0005] 1. Hot water heat exchange:
[0006] Its working principle is: directly exchange heat between hot water and high-temperature exhaust steam. Its working principle is through tube heat exchange. Hot water at about 50°C is directly exchanged with the exhaust steam to produce hot water at about 70°C. The characteristics of this solution are simple process and easy implementation. The disadvantage is that a large amount of the produced hot water cannot be fully used, and the heat energy that cannot be recycled finally escapes into the environment, failing to completely solve environmental pollution and energy waste.
[0007] 2. Heat pump heat exchange:
[0008] Its working principle is as follows: The first type or the second type of heat pump is adopted. By consuming a small amount of high-grade energy, such as electricity or natural gas, the refrigerant is used to convert low-grade heat energy such as the exhausted steam and the heat of circulating cooling water mentioned in this patent into medium-grade heat energy. The main purpose is to produce high-temperature hot water or low-pressure saturated steam for reuse in the process production device. However, due to the development of domestic technology and the uneven energy balance of the in-plant devices, the heat recovery efficiency is low, the construction and operation costs are high, the investment payback period is long, and even there is no profit. Many enterprises have the will but not the ability. Content of the Utility Model
[0009] The purpose of the present utility model is to introduce a system for recovering exhausted steam from the slag flushing water in the yellow phosphorus production process and jointly recovering the heat energy of the phosphorus furnace gas condensate circulating cooling water to produce low-pressure steam and process circulating hot water, so as to solve the problems of exhausted steam pollution generated by the water-quenched slag in the yellow phosphorus device and the pollution of the phosphorus-containing high-temperature circulating cooling water generated by the condensation of the phosphorus furnace gas. At the same time, the low-grade heat energy is recovered and converted into low-pressure steam and circulating high-temperature hot water for reuse in the device, reducing the production energy consumption. Using the traditional heat pump system to recover low-grade heat energy requires consuming the circulating cooling water to cool the refrigerant. Here, through the combined high-temperature refrigerant and low-temperature refrigerant systems for heat cascade replacement, there is no need to newly consume circulating cooling water, improving the energy conversion efficiency. The low-pressure steam and high-temperature hot water recovered by the patent scheme can be directly used in the process device. For example, the steam is used for heating the drying system of the yellow phosphorus raw materials, the high-temperature hot water is used for insulating the yellow phosphorus pipeline, and for heating the factory area in winter. The heat energy recovered can be balanced within the production system, thereby reducing the unit energy consumption of the production system and lowering the production cost.
[0010] The present utility model is completed through the following technical solutions. The system at least includes an exhausted steam recovery system, a high-temperature refrigerant exhausted steam heat energy conversion system, a superheated water flash evaporation low-pressure steam production system, a high-temperature phosphorus-containing circulating cooling water negative pressure flash evaporation system, a low-temperature refrigerant high-temperature circulating cooling water heat energy conversion system, and an electrical automatic control system. The specific solutions are as follows:
[0011] A heat energy recovery low-pressure steam and process circulating hot water system, in which the output end of the exhausted steam collection box is successively connected to the exhausted steam collection box through a high-temperature refrigerant screw compressor, a high-temperature refrigerant condenser, a steam superheater, and a high-temperature refrigerant cooler;
[0012] The output end of the return water of the circulating cooling water in the yellow phosphorus device is connected to the circulating water negative pressure flash evaporation system. The output end of the circulating water negative pressure flash evaporation system is successively connected to the low-temperature refrigerant evaporator, the low-temperature refrigerant screw compressor, and the low-temperature refrigerant condenser through the low-temperature refrigerant evaporator; the low-temperature refrigerant condenser also has an output end connected to the high-temperature refrigerant cooler.
[0013] In the technical solution of the present utility model: the output end of the high-temperature refrigerant condenser is connected to the hot water flash evaporator. The output end at the top of the hot water flash evaporator is connected to the steam superheater, and the output end at the bottom is connected to the high-temperature refrigerant condenser.
[0014] In the technical solution of the present utility model: The circulating water negative pressure flash evaporation system is divided into two output ends, one of which is connected to the middle of the circulating water negative pressure flash evaporation system, and the other is connected to the circulating cooling water supply output end.
[0015] In the technical solution of the present utility model: The high-temperature refrigerant screw compressor is equipped with a screw compressor drive motor; the low-temperature refrigerant screw compressor is equipped with a screw compressor drive motor.
[0016] In the technical solution of the present utility model: The exhaust steam collection box is provided with high-temperature refrigerant heat exchange tubes.
[0017] In the technical solution of the present utility model, using the principle of heat pump and adopting the refrigerant commonly used in industrial heating processes as the medium for energy conversion, the exhaust steam of the slag flushing water generated in the yellow phosphorus production process is condensed and recovered to produce low-pressure steam for reuse in the production device. At the same time, to further improve the energy recovery efficiency and improve the condensation conditions of the phosphorus furnace gas, the high-temperature circulating cooling water containing phosphorus is used as a heat source to conduct heat through the refrigerant, reducing the temperature of the high-temperature circulating cooling water while preheating the circulating hot water return used in the process. The preheated circulating hot water is introduced into the high-temperature refrigerant cooler of the exhaust steam recovery system to be further heated and then supplied for use in the plant process equipment or heating; a screw compressor is used to compress the gaseous refrigerant; a shell-and-tube heat exchanger is used to exchange heat between the refrigerant and water; a pressure reduction flash evaporation system is used to flash the superheated water to produce low-pressure saturated steam; a throttle valve is used to decompress and evaporate the refrigerant; a negative pressure flash evaporation system is used to evaporate and cool the high-temperature circulating cooling water.
[0018] In the technical solution of the present utility model, high-temperature and low-temperature refrigerants commonly used in the heat pump principle are used to condense and cool the high-temperature exhaust steam generated during slag flushing in the yellow phosphorus production process and the high-temperature circulating cooling water containing phosphorus generated during the condensation of the phosphorus furnace gas, and the derived thermal energy is converted into low-pressure steam and high-temperature hot water with a higher energy grade.
[0019] In the technical solution of the present utility model, the heat of the exhaust steam of the yellow phosphorus slag flushing water is absorbed during the gasification process of the liquid high-temperature refrigerant, the exhaust steam is condensed into a liquid, the high-temperature refrigerant is gasified into a gas state, and the gaseous high-temperature refrigerant is pressurized by a screw compressor to increase its pressure.
[0020] In the technical solution of the present utility model, circulating superheated water is used to cool and condense the high-temperature refrigerant after being pressurized by the screw compressor, and the superheated water after increasing the temperature enters the hot water pressure reduction flash evaporator to flash and produce low-pressure saturated steam.
[0021] In the technical solution of the present utility model, the flashed saturated steam exchanges heat with the liquefied high-temperature refrigerant through a steam superheater to become slightly superheated steam to improve the steam transmission performance.
[0022] In the technical solution of the present utility model, the circulating hot water return water after heating or process production is used to further cool the liquid high-temperature refrigerant, and at the same time, the temperature of the circulating hot water is increased.
[0023] In the technical solution of the present utility model, the further cooled high-temperature refrigerant is throttled by a throttle valve, and then exchanges heat with the waste steam of the slag flushing water generated in the yellow phosphorus production process to complete a cycle.
[0024] In the technical solution of the present utility model, the phosphorus-containing high-temperature circulating cooling water generated during the condensation of phosphorus furnace gas in the yellow phosphorus production process is flash-cooled by a negative pressure flash evaporator. The gas phase after the flash evaporation of the circulating water exchanges heat with the low-temperature refrigerant and condenses, and the originally liquid low-temperature refrigerant absorbs heat and evaporates into a gas phase.
[0025] In the technical solution of the present utility model, the evaporated low-temperature refrigerant is pressurized by a screw compressor. The pressurized low-temperature refrigerant exchanges heat with the heating or process hot water return water in the low-temperature refrigerant condenser and is cooled and condensed, and at the same time, the temperature of the hot water is increased.
[0026] In the technical solution of the present utility model, the circulating hot water used in the factory area first exchanges heat with the gaseous low-temperature refrigerant, and after the temperature is increased, it exchanges heat with the liquid high-temperature refrigerant to further increase the temperature to meet the process or heating use requirements, thereby improving the thermal efficiency of the entire system.
[0027] In the technical solution of the present utility model, while recovering the heat of the waste steam of the slag flushing water of the yellow phosphorus production device and the high-temperature circulating water generated by the condensation of phosphorus furnace gas, low-pressure steam and high-temperature hot water available for process devices are produced. At the same time, the pollution of the environment by high-temperature waste steam and phosphorus-containing high-temperature circulating water is reduced, and the consumption of the device's slag flushing water and circulating cooling water is reduced. Description of the Drawings
[0028] Figure 1 is the system diagram of the present utility model. Detailed Embodiments
[0029] The present utility model will be further described below in conjunction with embodiments, but the scope of the present utility model is not limited thereto:
[0030] Figure 1 As shown, the present utility model mainly consists of six interrelated subsystems: a waste steam recovery system A, a high-temperature refrigerant waste steam heat conversion system B, a circulating superheated water flash evaporation to produce low-pressure steam system C, a low-temperature refrigerant high-temperature circulating cooling water heat conversion system D, a phosphorus-containing high-temperature circulating cooling water negative pressure flash evaporation system E, and an electrical automatic control system F.
[0031] The waste steam recovery system A: It consists of a waste steam collection box and high-temperature refrigerant heat exchange tubes. Figure 1 Among them, the waste steam collection box A1 and the high-temperature refrigerant heat exchange tube A2.
[0032] High-temperature refrigerant exhaust steam thermal energy conversion system B: It consists of a high-temperature refrigerant screw compressor, a screw compressor drive motor, a high-temperature refrigerant condenser, a high-temperature refrigerant cooler, a high-temperature refrigerant throttle valve, etc. Figure 1 Among them, there are a high-temperature refrigerant screw compressor B1, a screw compressor drive motor B2, a high-temperature refrigerant condenser B3, a high-temperature refrigerant cooler B4, and a high-temperature refrigerant throttle valve B5.
[0033] Superheated water circulation flashing to produce low-pressure steam system C: It consists of a superheated water circulation pump, a superheated water flashing system, a steam superheater, relevant pipelines, etc. Figure 1 Among them, there are a superheated water circulation pump C1, a hot water flash evaporator C2, and a steam superheater C3.
[0034] Low-temperature refrigerant high-temperature circulating cooling water thermal energy conversion system D: It consists of a low-temperature refrigerant screw compressor, a screw compressor drive motor, a low-temperature refrigerant evaporator, a low-temperature refrigerant condenser, a low-temperature refrigerant throttle valve, etc. Figure 1 Among them, there are a low-temperature refrigerant screw compressor D1, a screw compressor drive motor D2, a low-temperature refrigerant evaporator D3, a low-temperature refrigerant throttle valve D4, and a low-temperature refrigerant condenser D5.
[0035] Phosphorus-containing high-temperature circulating cooling water negative pressure flashing system E: It consists of a circulating cooling water circulation pump, a circulating water negative pressure flashing system, relevant pipelines, etc. Figure 1 Among them, there are a circulating cooling water circulation pump E1 and a circulating water negative pressure flashing system E2.
[0036] Specifically: The thermal energy recovery to produce low-pressure steam and process circulating hot water system. The output end of the exhaust steam collection tank A1 is connected to the exhaust steam collection tank A1 through a high-temperature refrigerant screw compressor B1, a high-temperature refrigerant condenser B3, a steam superheater C3, a high-temperature refrigerant cooler B4 in sequence.
[0037] The output end of the return water of the circulating cooling water in the yellow phosphorus device is connected to the circulating water negative pressure flashing system E2. The output end of the circulating water negative pressure flashing system E2 is connected to the low-temperature refrigerant evaporator D3 through a low-temperature refrigerant evaporator D3, a low-temperature refrigerant screw compressor D1, and a low-temperature refrigerant condenser D5 in sequence; The low-temperature refrigerant condenser D5 also has an output end connected to the high-temperature refrigerant cooler B4.
[0038] The output end of the high-temperature refrigerant condenser B3 is connected to the hot water flash evaporator C2. The output end at the top of the hot water flash evaporator C2 is connected to the steam superheater C3, and the output end at the bottom is connected to the high-temperature refrigerant condenser B3.
[0039] The circulating water negative pressure flashing system E2 is divided into two output ends. One output end is connected to the middle of the circulating water negative pressure flashing system E2, and the other output end is connected to the output end of the circulating cooling water supply.
[0040] The high-temperature refrigerant screw compressor B1 is equipped with a screw compressor drive motor B2; the low-temperature refrigerant screw compressor D1 is equipped with a screw compressor drive motor D2.
[0041] The high-temperature refrigerant heat exchange tubes A2 are provided in the exhaust steam collection tank A1.
[0042] The working principle of the present utility model is as follows: The high-temperature exhaust steam generated by the slag flushing water of the yellow phosphorus device is collected through the exhaust steam collection tank A1 and exchanges heat with the high-temperature refrigerant heat exchange tubes A2. The high-temperature exhaust steam condenses into liquid water and flows back to the slag flushing pool. After absorbing heat, the high-temperature refrigerant changes from liquid to gas. The gaseous high-temperature refrigerant enters the high-temperature refrigerant screw compressor B1 driven by the screw compressor drive motor B2, and after further pressurization to increase the pressure and temperature, it exchanges heat with the circulating heated superheated water in the high-temperature refrigerant condenser B3 and condenses into liquid. The liquid high-temperature refrigerant exchanges heat with the low-pressure saturated steam in the steam superheater C3 and then enters the high-temperature refrigerant cooler B4 to exchange heat and cool with the preheated high-temperature process hot water return water, and then passes through the high-temperature refrigerant throttle valve B5 for throttling and decompression and then re-enters the exhaust steam collection tank A1 to exchange heat and evaporate with the exhaust steam to complete one cycle. The superheated water heated in the high-temperature refrigerant condenser enters the hot water flash evaporator C2 for flashing. The low-pressure steam is led out from the upper part of the flash evaporator and enters the steam superheater C3 to be superheated into superheated steam and then sent to the factory area for use. The saturated water after flashing is pressurized by the hot water pump C1 and then sent to the high-temperature refrigerant condenser B3 for heating to complete one cycle.
[0043] The phosphorus-containing high-temperature circulating cooling water coming out of the phosphorus furnace gas condensation tower of the yellow phosphorus production device is sent through a pipeline to the circulating water negative pressure flash evaporator E2 for flash evaporation and cooling. The phosphorus-containing circulating water gas phase is led out from the top and enters the low-temperature refrigerant evaporator D3 to exchange heat with the liquid low-temperature refrigerant. After that, the gaseous phosphorus-containing circulating cooling water re-condenses into liquid, and the liquid low-temperature refrigerant absorbs heat and evaporates into gas; to increase the flash evaporation power, a circulating cooling water circulation pump E1 is arranged at the low position of the negative pressure flash evaporator to provide flash evaporation power for the circulating cooling water in the negative pressure flash evaporator, increase the evaporation area, and at the same time, a part of the circulating cooling water at the pump outlet is incorporated into the circulating cooling water condensed from the gas phase and then sent back to the phosphorus furnace gas condensation tower of the yellow phosphorus production device; the gaseous low-temperature refrigerant coming out of the low-temperature refrigerant evaporator D3 is pressurized by the low-temperature refrigerant screw compressor D1 driven by the screw compressor drive motor D2 and then enters the low-temperature refrigerant condenser D5 to exchange heat with the circulating hot water after process use and then condenses into liquid. The liquid low-temperature refrigerant passes through the low-temperature refrigerant throttle valve D4 for throttling and decompression and then returns to the low-temperature refrigerant evaporator D3 to condense the gaseous phosphorus-containing circulating cooling water, thereby realizing one cycle.
[0044] The circulating hot water return water for process use first exchanges heat and is heated up in the low-temperature refrigerant condenser D5 with the low-temperature refrigerant, and the heated hot water return water then enters the high-temperature refrigerant cooler to further exchange heat and increase the temperature with the high-temperature refrigerant and then returns to the process production for use.
[0045] In terms of electrical instrument control, the system controls the temperature and pressure parameters of each subsystem through the distributed control system (DCS) to regulate the high and low temperature refrigerant parameters, so as to optimize the efficiency of the whole system.
[0046] Figure 1 As shown, the slag flushing water exhaust steam recovery and combined phosphorus furnace gas condensation circulating cooling water heat energy recovery system for producing low-pressure steam and process circulating hot water of the yellow phosphorus production process described in the present utility model. When taking 8 t / h of atmospheric exhaust steam and 60 t / h of high-temperature phosphorus-containing circulating cooling water as input conditions; taking 6.4 t / h of superheated steam at 0.188 Mpa and 123 °C, and 125 t / h of process circulating hot water with an inlet temperature of 45 °C and an outlet temperature of 75 °C as output conditions; through calculation, it is obtained that the high-temperature refrigerant screw compressor needs to consume 860 kw of electric power, the low-temperature refrigerant screw compressor needs to consume 360 kw of electric power, and other electrical equipment, including pumps, valves, vacuum units, etc., consume a total of about 150 kw of electric power, with a total power consumption of 1370 kw. The converted heating power of the produced steam is 3865 kw, and the heating power of the produced hot water is 4375 kw, with a total heating power of 8240 kw. The coefficient of performance (COP) reaches 6.01, far exceeding the calculated COP of 4.0 of a general heat pump. At the same time, the low-pressure steam generated by the system can be used for raw material drying, sludge phosphorus heating, etc., and the hot water can be used for heat tracing and insulation of yellow phosphorus pipelines, water seals for yellow phosphorus storage, etc., all of which can be used well, and the recovered heat energy will not be wasted. Most importantly, after the system is established, there is no exhaust steam escaping into the environment, and the high-temperature phosphorus-containing circulating cooling water does not need to be cooled by a cooling tower, thus reducing the pollution of the production device to the environment.
Claims
1. Heat energy recovery low-pressure steam and process circulating hot water system, characterized in that: The output end of the exhaust steam collection tank (A1) is connected in sequence to the exhaust steam collection tank (A1) through a high-temperature refrigerant screw compressor (B1), a high-temperature refrigerant condenser (B3), a steam superheater (C3), a high-temperature refrigerant cooler (B4). The output end of the return water of the circulating cooling water in the yellow phosphorus plant is connected to the circulating water negative pressure flash evaporation system (E2). The output end of the circulating water negative pressure flash evaporation system (E2) is connected in sequence to the low-temperature refrigerant evaporator (D3), the low-temperature refrigerant screw compressor (D1), and the low-temperature refrigerant condenser (D5) and then back to the low-temperature refrigerant evaporator (D3). The low-temperature refrigerant condenser (D5) also has an output end connected to the high-temperature refrigerant cooler (B4).
2. The heat energy recovery system for producing low-pressure steam and process circulating hot water according to claim 1, wherein: The output end of the high-temperature refrigerant condenser (B3) is connected to the hot water flash evaporator (C2). The output end at the top of the hot water flash evaporator (C2) is connected to the steam superheater (C3), and the output end at the bottom is connected to the high-temperature refrigerant condenser (B3).
3. The heat energy recovery low-pressure steam and process circulating hot water system according to claim 1, wherein: The circulating water negative pressure flash evaporation system (E2) is divided into two output ends. One output end is connected to the middle part of the circulating water negative pressure flash evaporation system (E2), and the other output end is connected to the output end of the circulating cooling water supply.
4. The heat energy recovery low-pressure steam and process circulating hot water system according to claim 1, characterized in that: The high-temperature refrigerant screw compressor (B1) is equipped with a first screw compressor drive motor (B2); the low-temperature refrigerant screw compressor (D1) is equipped with a second screw compressor drive motor (D2).
5. The heat energy recovery system for producing low-pressure steam and process circulating hot water according to claim 1, wherein: The exhaust steam collection tank (A1) is provided with high-temperature refrigerant heat exchange tubes (A2).