Low-temperature waste heat utilization system of trioxymethylene reaction system

Abstract

The utility model discloses a low-temperature waste heat utilization system of a trioxymethylene reaction system, which is characterized in that the bottom of a reactor is connected with a heater, the top of the reactor is connected with a condenser, a tube pass outlet of the condenser is connected with a dilute trioxymethylene storage tank, a shell pass outlet of the condenser is connected with a hot water tank, and the hot water tank is connected with a first inlet of a low-temperature waste heat utilization device; a shell pass outlet of the heater is connected with a second inlet of the low-temperature waste heat utilization device, a third inlet of the low-temperature waste heat utilization device is connected with a condensate water source, a hot water outlet of the low-temperature waste heat utilization device is connected with the condenser, and a steam outlet of the low-temperature waste heat utilization device is connected with the heater. The temperature of the part, passing through the condenser, of the gas phase of the reactor is obviously reduced, the consumption of circulating water used for cooling hot water from the condenser is greatly reduced, the pressure of the reactor is reduced, the unit consumption of trioxymethylene steam is reduced, the conversion rate of trioxymethylene is obviously increased, and the yield of the reactor is obviously increased. The device is of great significance in safe and stable operation, capacity utilization rate improvement and yield improvement.

Description

Technical Field

[0001] This utility model belongs to the field of trioxymethylene production technology, specifically relating to a low-temperature waste heat utilization system for a trioxymethylene reaction system. Background Technology

[0002] In the production of trioxymethylene using sulfuric acid as a catalyst, formaldehyde and sulfuric acid at the bottom of reactor 1 react after being heated by heater 2. The gas phase exiting from the top of reactor 1 splits into two paths: one path, in gaseous form, goes directly to the trioxymethylene concentration tower as a heating source, while the other path passes through condenser 3, becomes liquid, and enters the dilute trioxymethylene storage tank 17. This liquid gas phase, after passing through condenser 3, needs to be condensed with water at approximately 80°C. If the heated water is cooled by circulating water, a large amount of circulating water is required for reuse, resulting in energy waste. If air cooling or natural cooling is used, the circulating water temperature will fluctuate with air temperature changes, leading to highly unstable hot water temperature and affecting the safe and stable operation of the equipment. In addition, the heat exchange efficiency of the condenser deteriorates after a period of operation. These factors all affect the condenser outlet temperature, which in turn affects the pressure and temperature of the reactor, thus impacting the trioxymethylene conversion rate. Summary of the Invention

[0003] To address the problems of high and unstable condenser discharge temperature, high reactor pressure, low conversion rate, high energy consumption, and high heat source steam consumption in the production of trioxymethylene, this invention provides a low-temperature waste heat utilization system for the trioxymethylene reaction system.

[0004] The objective of this utility model is achieved in the following manner:

[0005] A low-temperature waste heat utilization system for a trioxymethylene reaction system includes a reactor, a heater, a condenser, and a hot water tank. The bottom outlet of the reactor is connected to the tube-side inlet of the heater, the top gas phase outlet of the reactor is connected to the tube-side inlet of the condenser, the tube-side outlet of the heater is connected to the inlet of the reactor, the shell-side inlet of the heater is connected to a steam source via a heat source flow meter and a steam flow regulating valve, the tube-side outlet of the condenser is connected to a dilute trioxymethylene storage tank, the shell-side outlet of the condenser is connected to the inlet of the hot water tank via a return water regulating valve, the outlet of the hot water tank is connected to the first inlet of the low-temperature waste heat utilization device via a hot water transfer pump, the shell-side outlet of the heater is connected to the second inlet of the low-temperature waste heat utilization device via a condensate drain valve and a second condensate valve, the third inlet of the low-temperature waste heat utilization device is connected to a condensate water source via a first water supply valve, the hot water outlet of the low-temperature waste heat utilization device is connected to the shell-side inlet of the condenser via a return water flow meter, and the steam outlet of the low-temperature waste heat utilization device is connected to the shell-side inlet of the heater via a flash steam flow meter.

[0006] The low-temperature waste heat utilization device includes a generator, a refrigerant storage tank, a refrigerant condenser, an evaporator, an absorber, a gas-liquid separator, a lithium bromide solution transfer pump, a refrigerant transfer pump, a heat exchanger, and a vacuum pump. The generator contains a lithium bromide aqueous solution. The generator, refrigerant condenser, evaporator, and absorber are connected to the vacuum pump. The inlet of the generator's hot water medium is connected to the outlet of the evaporator tube side, and the inlet of the evaporator tube side is connected to the outlet of the hot water tank. The outlet of the generator's hot water medium is connected to the condenser through a return water flow meter.

[0007] The lithium bromide outlet of the generator is connected to the first inlet of the heat exchanger via a lithium bromide solution transfer pump. The first outlet of the heat exchanger is connected to the lithium bromide inlet of the absorber. The lithium bromide outlet of the absorber is connected to the second inlet of the heat exchanger. The second outlet of the heat exchanger is connected to the lithium bromide inlet of the generator.

[0008] The steam outlet of the generator is connected to the shell-side inlet of the refrigerant condenser, the shell-side outlet of the refrigerant condenser is connected to the inlet of the refrigerant storage tank, the outlet of the refrigerant storage tank is connected to the tube-side inlet of the evaporator via a refrigerant transfer pump, and the tube-side outlet of the evaporator is connected to the refrigerant inlet of the absorber; the first inlet of the absorber is connected to the condensate water source via the first water supply valve, the first outlet of the absorber is connected to the gas-liquid separator, and the steam outlet of the gas-liquid separator is connected to the shell-side inlet of the heater.

[0009] The steam flow regulating valve, condensate trap, and return water regulating valve are all equipped with bypasses, and manual valves are connected to the bypass pipelines.

[0010] The hot water tank is connected to the water source through the hot water tank inlet valve.

[0011] The shell-side outlet of the heater is connected to the condensate storage tank via the first condensate valve.

[0012] The liquid outlet of the gas-liquid separator is connected to the refrigerant inlet of the absorber.

[0013] Compared with the prior art, this utility model discloses a low-temperature waste heat utilization system for a trioxymethylene reaction system. The temperature of the material in the gas phase of the reactor is significantly reduced after passing through the condenser. The amount of circulating water used to cool the hot water coming out of the condenser is greatly reduced, the reactor pressure is reduced, the trioxymethylene steam consumption is reduced, the trioxymethylene conversion rate is significantly improved, and the reactor output is significantly increased. This is of great significance for the safe and stable operation of the equipment, the improvement of capacity utilization, and the increase in output. Attached Figure Description

[0014] Figure 1 This is a simplified structural diagram of the utility model.

[0015] Figure 2 This is a simplified structural diagram of a low-temperature waste heat utilization device.

[0016] In the diagram: 1-Reactor, 2-Heater, 3-Condenser, 4-Steam Flow Control Valve, 5-Condensate Steam Trap, 6-Heat Source Flow Meter, 7-Return Water Control Valve, 8-Flash Steam Flow Meter, 9-Return Water Flow Meter, 10-Low Temperature Waste Heat Utilization Device, 101-Generator, 102-Refrigerant Storage Tank, 103-Refrigerant Condenser, 104-Evaporator, 105-Absorber, 106-Gas-Liquid Separator, 107-Lithium Bromide Solution Transfer Pump, 108-Refrigerant Transfer Pump, 1013-Heat Exchanger, 1014-Air Pump, 11-First Water Supply Valve, 12-Hot Water Tank, 13-Hot Water Transfer Pump, 14-Hot Water Tank Water Supply Valve, 15-First Condensate Valve, 16-Second Condensate Valve, 17-Dilute Trioxymethylene Storage Tank, 18-Condensate Storage Tank. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are only for illustrating the present invention and are not intended to limit the scope of the present invention. After reading the contents of the present invention, those skilled in the art can make various modifications or alterations to the present invention, and these equivalent forms also fall within the scope defined by the present invention.

[0018] like Figure 1 As shown, a low-temperature waste heat utilization system for a trioxymethylene reaction system includes a reactor 1, a heater 2, a condenser 3, and a hot water tank 12. The bottom outlet of the reactor is connected to the tube-side inlet of the heater, the top gas phase outlet of the reactor is connected to the tube-side inlet of the condenser, the tube-side outlet of the heater is connected to the inlet of the reactor, the shell-side inlet of the heater is connected to a steam source via a heat source flow meter 6 and a steam flow regulating valve 4, the tube-side outlet of the condenser is connected to a dilute trioxymethylene storage tank 17, the shell-side outlet of the condenser is connected to the inlet of the hot water tank 12 via a return water regulating valve 7, the outlet of the hot water tank 12 is connected to the first inlet of a low-temperature waste heat utilization device 10 via a hot water transfer pump 13, the shell-side outlet of the heater is connected to the second inlet of the low-temperature waste heat utilization device 10 via a condensate drain valve 5 and a second condensate valve 16, the third inlet of the low-temperature waste heat utilization device 10 is connected to a condensate water source via a first water supply valve 11, the hot water outlet of the low-temperature waste heat utilization device 10 is connected to the shell-side inlet of the condenser via a return water flow meter 9, and the steam outlet of the low-temperature waste heat utilization device 10 is connected to the shell-side inlet of the heater via a flash steam flow meter 8.

[0019] In reactor 1, the formaldehyde and sulfuric acid catalyst in the reaction liquid are vaporized by steam heating in heater 2. The gaseous output from the top of reactor 1 is divided into two paths: one path goes directly to the lower part of the trioxymethylene concentration tower in gaseous form, and the other path is cooled down by condenser 3 and becomes liquid, entering dilute trioxymethylene storage tank 18. Condenser 3 uses 80°C hot water as the heat exchange medium. After passing through condenser 3, the temperature rises to 110°C. The 110°C hot water is used as the heating source. In the low-temperature waste heat utilization device 10, the condensed water at 90-110°C entering the device is flashed into steam by lithium bromide solution. The temperature drops from 110°C to 80°C and then enters condenser 3 to condense and exchange heat for recycling.

[0020] High-temperature water at approximately 110°C from hot water tank 12 enters low-temperature waste heat recovery device 10 as a heat source. Within device 10, lithium bromide solution absorbs heat from the hot water, causing the condensate at 90-110°C to flash-evaporate into the required steam, which then enters heater 2 to heat reactor 1. The condensate formed after the steam generated by flash evaporation in device 10 is used is recycled back into device 10 as a steam source, continuing to flash-evaporate into steam for reuse. When the amount of steam generated by flash evaporation is insufficient, the original steam source is used to heat reactor 1.

[0021] like Figure 2 As shown, the low-temperature waste heat utilization device 10 includes a generator 101, a refrigerant storage tank 102, a refrigerant condenser 103, an evaporator 104, an absorber 105, a gas-liquid separator 106, a lithium bromide solution transfer pump 107, a refrigerant transfer pump 108, a heat exchanger 1013, and a vacuum pump 1014. The generator 101 contains a lithium bromide aqueous solution, and the refrigerant in the refrigerant storage tank 102 is demineralized water. The generator 101, the refrigerant condenser 103, the evaporator 104, and the absorber 105 are connected to the vacuum pump 1014.

[0022] The inlet of the generator 101 is connected to the tube-side outlet of the evaporator 104, and the inlet of the tube-side of the evaporator 104 is connected to the outlet of the hot water tank 12; the outlet of the generator 101 is connected to the condenser 3 through the return water flow meter 9.

[0023] The lithium bromide outlet of generator 101 is connected to the first inlet of heat exchanger 1013 via lithium bromide solution transfer pump 107. The first outlet of heat exchanger 1013 is connected to the lithium bromide inlet of absorber 105. The lithium bromide outlet of absorber 105 is connected to the second inlet of heat exchanger 1013. The second outlet of heat exchanger 1013 is connected to the lithium bromide inlet of generator 101.

[0024] The steam outlet of generator 101 is connected to the shell-side inlet of refrigerant condenser 103, the shell-side outlet of refrigerant condenser 103 is connected to the inlet of refrigerant storage tank 102, the outlet of refrigerant storage tank 102 is connected to the tube-side inlet of evaporator 104 via refrigerant transfer pump 108, and the tube-side outlet of evaporator 104 is connected to the refrigerant inlet of absorber 105; the first inlet of absorber 105 is connected to condensate water source via first water supply valve 11, the first outlet of absorber 105 is connected to gas-liquid separator 106, and the steam outlet of gas-liquid separator 106 is connected to the shell-side inlet of heater 2.

[0025] In lithium bromide absorption chillers, because the aqueous lithium bromide solution itself has a very high boiling point (1265℃) and is extremely difficult to volatilize, the vapor on the surface of a saturated lithium bromide solution can be considered as pure water vapor. At a given temperature, the saturated partial pressure of water vapor on the surface of the lithium bromide aqueous solution is lower than that of pure water, and the higher the concentration, the lower the saturated partial pressure of water vapor on the surface. Therefore, under the same temperature conditions, the higher the concentration of the lithium bromide aqueous solution, the stronger its ability to absorb moisture. This is why lithium bromide is usually used as the absorbent and water as the refrigerant.

[0026] The low-temperature waste heat utilization device 10 of this utility model includes a generator 101, a refrigerant storage tank 102, a refrigerant condenser 103, an evaporator 104, an absorber 105, a gas-liquid separator 106, a lithium bromide solution transfer pump 107, a refrigerant transfer pump 108, a heat exchanger 1013, and a vacuum pump 1014.

[0027] The heat source for the low-temperature waste heat recovery device 10 is the heat transfer medium water that enters the generator 101 after heat exchange in the hot water tank 12 via the evaporator 104 (see...). Figure 2 (Blue line).

[0028] Preferably, the hot water entering the low-temperature waste heat utilization device 10 from the hot water tank 12 is at a temperature of 110°C. After heat exchange in the evaporator 104, it becomes 100°C. After heat exchange in the generator 101, it becomes 75°C hot water and enters the condenser 3 for use.

[0029] The refrigerant circulation of the low-temperature waste heat recovery device 10 is as follows: Figure 2 As shown by the red line, the water (refrigerant) in the dilute lithium bromide solution is continuously vaporized in the generator 101 under the heating of the hot water. The generated water vapor enters the refrigerant condenser 103, is cooled by the cooling water in the refrigerant condenser 103, and condenses into high-pressure, low-temperature liquid water. This liquid water enters the refrigerant storage tank 102 and is then pumped into the evaporator 104 by the refrigerant transfer pump 108. It absorbs heat from the hot water entering the evaporator 104 from the hot water tank 12 and rapidly expands and vaporizes. During the vaporization process, it also absorbs a large amount of heat from the hot water in the evaporator 104 (see...). Figure 2(As shown by the red line) The low-temperature water vapor formed by vaporization enters the absorber 105, mixes with the lithium bromide solution, and then returns to the generator 101 along with the lithium bromide solution, where it is heated, condensed, and evaporated again.

[0030] Preferably, the refrigerant (deionized water) in the refrigerant storage tank 102 is at a temperature of 40°C. It is pumped into the evaporator 104 by the refrigerant transfer pump 108, heated to 46°C by the 110°C hot water from the hot water tank 12, and the pressure becomes -90kPa. It enters the absorber 105, and then returns to the generator 101 after heat exchange with the 110°C lithium bromide solution through the heat exchanger 1013. In the generator 101, it is heated and condensed again to evaporate into 46°C, -92kPa steam. It is then cooled and condensed into 40°C liquid water by the refrigerant condenser 103 and returns to the refrigerant storage tank 102.

[0031] The lithium bromide cycle of the low-temperature waste heat utilization device 10 is as follows: Figure 2 As shown by the magenta line, the lithium bromide aqueous solution in generator 101 is heated by the heat transfer medium water, and its concentration continuously increases to become a concentrated solution of about 60%. It is then pumped into heat exchanger 1013 by lithium bromide solution transfer pump 107 for heat exchange and then enters absorber 105. In absorber 105, it absorbs refrigerant vapor from evaporator 104 and releases a large amount of heat. After absorbing the refrigerant vapor, the concentration of lithium bromide concentrated solution decreases. After passing through heat exchanger 1013, it re-enters generator 101 for separation. In heat exchanger 1013, the high-temperature dilute lithium bromide solution flowing out of absorber 105 exchanges heat with the low-temperature concentrated solution flowing out of generator 101.

[0032] Preferably, the lithium bromide aqueous solution at around 70°C in the generator 101 is heated to 75°C by the 100°C hot medium water, and then heat-exchanged to 110°C by the heat exchanger 1013 before entering the absorber 105. In the absorber 105, the absorber absorbs the refrigerant vapor from the evaporator 104 and releases a large amount of heat. The concentration of the lithium bromide concentrated solution decreases, and the temperature change is not significant. After heat-exchanging again by the heat exchanger 1013, the solution returns to the generator 101.

[0033] The vacuum pump 1014 is used to extract pressure from the generator 101, refrigerant condenser 103, evaporator 104, and absorber 105, creating a negative pressure of -90 kPa within the system. At this pressure, the boiling point of water vapor is approximately 46°C. Due to pressure losses in the system pipelines, there may be slight pressure variations in pipelines located far from the vacuum pump 1014. For example, the pressure at the generator 101 may be slightly lower, approximately -92 kPa. These slight pressure variations do not affect the normal operation of the system, and the system's pressure design takes into account pipeline pressure losses while ensuring normal system operation.

[0034] The large amount of heat released by the lithium bromide solution in the absorber 105 is absorbed by the condensate. The temperature of the condensate gradually increases from 100°C to about 133°C. The condensate is separated into 0.3 MPa (A) steam by the gas-liquid separator 106 and enters the shell side of the heater through valve 1012 and flash steam flow meter 8.

[0035] Furthermore, the liquid outlet of the gas-liquid separator 106 is connected to the refrigerant inlet of the absorber 105, so that the liquid separated by the gas-liquid separator 106 is reintroduced into the absorber 105 along with the condensate water source for flash evaporation to form steam.

[0036] Furthermore, the hot water tank 12 is connected to a water source via the hot water tank inlet valve 14. Depending on the system's operating status and ambient temperature, the hot water tank 12 is replenished with either hot or cold water. For example, during the initial operation phase, the hot water tank 12 is connected to a cold water source via the hot water tank inlet valve 14; generally, cold water is replenished when the ambient temperature is high in summer, and hot water is replenished when the ambient temperature is low in winter.

[0037] Furthermore, the shell-side outlet of the heater is connected to the condensate storage tank 18 via the first condensate valve 15. The condensate in the condensate storage tank 18 can be used for pipe network heating, hot water for daily use, etc.

[0038] The low-temperature waste heat utilization process absorbs the temperature of the condenser cooling water to produce 4t / h of 0.3MPa saturated steam, reduces the condenser outlet temperature by 3℃, reduces the reactor pressure by 5kPa, increases the paraformaldehyde conversion rate from 14% to 16.5%, and reduces steam consumption from 13t / t to 10t / t.

[0039] The above description is only a preferred embodiment of the present utility model. It should be noted that those skilled in the art can make several changes and improvements without departing from the overall concept of the present utility model, and these should also be considered within the protection scope of the present utility model.

[0040] Example:

[0041] To verify the actual effect of the low-temperature waste heat utilization system of the trioxymethylene reaction system described in this utility model, an industrial application test was conducted in a production plant with an annual output of 50,000 tons of trioxymethylene. The specific implementation steps are as follows:

[0042] 1. System Installation and Debugging

[0043] The low-temperature waste heat utilization system described in this utility model (such as...) Figure 1 , Figure 2(As shown) It is integrated with the original trioxymethylene reaction system. The hot water inlet of the low-temperature waste heat utilization device 10 is connected to the outlet of the hot water tank 12, and the steam outlet is connected to the shell inlet of the heater 2. The condensate water source is replenished through the first water supply valve 11. Before the system is started, key parameters such as the lithium bromide solution concentration, the demineralized water level of the refrigerant storage tank 102, and the negative pressure state of the vacuum pump 1014 are calibrated to ensure that the system operating conditions meet the design requirements.

[0044] 2. Operating Parameter Settings

[0045] Initial conditions:

[0046] Feed flow rate of reactor 1: 12 t / h (formaldehyde solution, containing sulfuric acid catalyst);

[0047] Steam pressure of heater 2: 0.5 MPa (G);

[0048] Initial temperature of circulating hot water in condenser 3: 80℃;

[0049] Ambient temperature: 25℃ (summer operating conditions).

[0050] Operating parameters of the low-temperature waste heat recovery device 10:

[0051] Heat transfer water (from hot water tank 12) temperature: 110℃;

[0052] Flash steam pressure: 0.3 MPa (A);

[0053] Lithium bromide solution concentration: 60% (generator 101 outlet).

[0054] 3. Data monitoring and comparison

[0055] The system ran continuously for 72 hours, collecting key parameters and comparing them with data from before the modification:

[0056]

[0057] 4. Effectiveness Verification Methods

[0058] Temperature and pressure monitoring:

[0059] High-precision thermocouples (accuracy ±0.5℃) are used to collect the material temperature at the outlet of condenser 3 and the pressure of reactor 1 in real time. The data logger stores the data every 10 minutes.

[0060] Conversion rate calculation: The conversion rate is calculated by analyzing the paraformaldehyde content in the reactor outlet material using gas chromatography and comparing it with the formaldehyde feed rate.

[0061] Steam consumption metering: The cumulative consumption of the original steam source and the by-product steam is recorded by heat source flow meter 6 and flash steam flow meter 8, respectively.

[0062] 5. Results Analysis

[0063] The low-temperature waste heat utilization device 10 uses lithium bromide absorption heat pump technology to convert the waste heat of 110℃ hot water into 0.3MPa steam, which is directly reused in heater 2, reducing the original steam consumption.

[0064] The circulating hot water temperature in condenser 3 is kept stable at 80℃, avoiding temperature fluctuations caused by traditional circulating water cooling and improving system stability.

[0065] The reactor pressure was reduced by 5 kPa, which optimized the reaction equilibrium conditions and significantly improved the conversion rate of paraformaldehyde.

[0066] 6. Conclusion

[0067] This embodiment demonstrates that the low-temperature waste heat recovery system can effectively recover low-temperature waste heat from the reaction system, with by-product steam replacing part of the original steam consumption, while simultaneously stabilizing condenser operation and improving reaction efficiency. Data shows that steam consumption is reduced by 23% and conversion rate is increased by 18%, demonstrating significant economic and environmental benefits, meeting the requirements for industrial applications.

[0068] Note: The above data are test results under specific working conditions. The actual results may vary slightly due to factors such as the scale of the device and operating conditions, but the technical principles and core advantages remain unchanged.

Claims

1. A low-temperature waste heat utilization system of a trioxane reaction system, comprising a reactor (1), a heater (2), a condenser (3) and a hot water tank (12), the bottom outlet of the reactor is connected to the tube inlet of the heater, the top gas phase outlet of the reactor is connected to the tube inlet of the condenser, the tube outlet of the heater is connected to the inlet of the reactor, the shell inlet of the heater is connected to a steam source through a heat source flow meter (6) and a steam flow regulating valve (4), the tube outlet of the condenser is connected to a dilute trioxane storage tank (17), and the shell outlet of the condenser is connected to the inlet of the hot water tank (12) through a backwater regulating valve (7), characterized in that: The outlet of the hot water tank (12) is connected to the first inlet of the low-temperature waste heat utilization device (10) through a hot water delivery pump (13), the shell side outlet of the heater is connected to the second inlet of the low-temperature waste heat utilization device (10) through a condensate trap (5) and a second condensate valve (16), the third inlet of the low-temperature waste heat utilization device (10) is connected to a condensate water source through a first condensate valve (11), the hot water outlet of the low-temperature waste heat utilization device (10) is connected to the shell side inlet of the condenser through a backwater flow meter (9), and the steam outlet of the low-temperature waste heat utilization device (10) is connected to the shell side inlet of the heater through a flash steam flow meter (8). ​ The low-temperature waste heat utilization device (10) comprises a generator (101), a refrigerant storage tank (102), a refrigerant condenser (103), an evaporator (104), an absorber (105), a gas-liquid separator (106), a lithium bromide solution delivery pump (107), a refrigerant delivery pump (108), a heat exchanger (1013) and a gas extraction pump (1014), the generator (101) is provided with lithium bromide aqueous solution, the generator (101), the refrigerant condenser (103), the evaporator (104) and the absorber (105) are connected to the gas extraction pump (1014); the heat medium water inlet of the generator (101) is connected to the tube side outlet of the evaporator (104), and the tube side inlet of the evaporator (104) is connected to the outlet of the hot water tank (12); the heat medium water outlet of the generator (101) is connected to the condenser (3) through the backwater flow meter (9); The lithium bromide outlet of the generator (101) is connected to the first inlet of the heat exchanger (1013) through the lithium bromide solution delivery pump (107), the first outlet of the heat exchanger (1013) is connected to the lithium bromide inlet of the absorber (105), the lithium bromide outlet of the absorber (105) is connected to the second inlet of the heat exchanger (1013), and the second outlet of the heat exchanger (1013) is connected to the lithium bromide inlet of the generator (101); The water vapor outlet of the generator (101) is connected to the shell side inlet of the refrigerant condenser (103), the shell side outlet of the refrigerant condenser (103) is connected to the inlet of the refrigerant storage tank (102), the outlet of the refrigerant storage tank (102) is connected to the tube side inlet of the evaporator (104) through the refrigerant delivery pump (108), and the tube side outlet of the evaporator (104) is connected to the refrigerant inlet of the absorber (105); the first inlet of the absorber (105) is connected to the condensate water source through the first condensate valve (11), the first outlet of the absorber (105) is connected to the gas-liquid separator (106), and the steam outlet of the gas-liquid separator (106) is connected to the shell side inlet of the heater (2).

2. The low-temperature waste heat utilization system of the par formaldehyde reaction system according to claim 1, characterized in that: The steam flow regulating valve (4), the condensate trap (5) and the backwater regulating valve (7) are all provided with bypasses, and manual valves are connected to the bypass pipelines.

3. The low-temperature waste heat utilization system of the par formaldehyde reaction system according to claim 1, characterized in that: The hot water tank (12) is connected to a water source through a hot water tank condensate valve (14).

4. The low-temperature waste heat utilization system of the par formaldehyde reaction system according to claim 1, characterized in that: The shell side outlet of the heater (2) is connected to a condensate storage tank (18) through a first condensate valve (15).

5. The low-temperature waste heat utilization system of the paraffin reaction system according to claim 1, characterized in that: The liquid outlet of the gas-liquid separator (106) is connected to the refrigerant inlet of the absorber (105).

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