Evaporator dead steam utilization system

Abstract

The utility model relates to the technical field of evaporator waste heat utilization, in particular to an evaporator dead steam utilization system. The evaporator dead steam utilization system comprises an evaporator, a condenser, a hot well, a vacuum pump, a condensate pump and a circulating water pump, vacuum slightly lower than a production system is formed in the condenser through the vacuum pump, and last-effect dead steam or other air sources in the production system are pumped into the condenser along a pipeline and continuously exchange heat with circulating water to form condensate water. Circulating water heated by heat generated through phase change is discharged through a condensate pump and used for heating of residents in winter or for other purposes. In addition, through matched use of a sensor and an electromagnetic valve in the system, automatic control of the system is achieved, and thermal efficiency utilization of dead steam is improved. According to the method, waste steam heat which is originally useless in the production process is used for heating circulating water, energy consumption is greatly reduced, meanwhile, the heating problem of residents in living quarters is solved, the process is simple, the reproducibility is high, the application range is wide, and obvious technical advantages and economic advantages are achieved.

Description

TECHNICAL FIELD

[0001] The utility model relates to evaporator waste heat utilization technical field, concretely relates to a kind of evaporator steam exhaust utilization system. BACKGROUND

[0002] In many industrial production processes and some specific energy utilization systems, evaporators play a very key role. Evaporators evaporate liquid substances by heating medium, so as to realize the separation, concentration or purification of substances and other purposes. However, during the operation of the evaporator, a large amount of waste heat is often directly discharged into the environment, which not only causes serious energy waste, but also may cause heat pollution and other adverse effects to the surrounding environment.

[0003] With the continuous rise of energy costs and the increasing global attention to energy saving and emission reduction, improving energy utilization efficiency has become an important challenge for various industries. Traditional evaporators usually only focus on the efficiency and effect of the evaporation process itself, and lack effective design and technical means for waste heat recovery and utilization. For example, in the evaporation process of the alumina production industry, high-temperature steam is used as a heating source to evaporate the solution, and the large amount of latent heat released by steam condensation and the heat emitted by the evaporator itself cannot be fully utilized, but is discharged with cooling water or waste gas.

[0004] Currently, although there are some technologies and methods for industrial waste heat utilization, for example, a kind of evaporative process steam exhaust waste heat recovery and utilization system is disclosed in Chinese patent CN210004496U, in which the steam is exchanged with condensing water in the condenser, and the heat is used for heating the heating water to realize the utilization of waste heat. However, this device still has the problems of low heat exchange efficiency, poor system integration, low automation degree, etc., and it is difficult to be widely applied in different scales and types of evaporator systems. Therefore, a new type of evaporator steam exhaust utilization system with high efficiency and economic feasibility is needed to solve the above problems in the prior art and realize the maximum recovery and rational utilization of evaporator waste heat. SUMMARY

[0005] In order to solve the problems of the prior art, a kind of evaporator steam exhaust utilization system with high heat exchange efficiency, high system integration and high automation is provided, and the following technical solutions are proposed:

[0006] The system comprises an evaporator, a condenser, a hot well, a vacuum pump, a condensate pump, and a circulating water pump, wherein the steam outlet of the evaporator is connected with the steam inlet of the condenser, and an electric vacuum valve is arranged between the steam outlet and the steam inlet; a heat exchanger is arranged in the condenser, the heat exchanger comprises a cold fluid channel and a hot fluid channel, the steam inlet end of the hot fluid channel is connected with the steam inlet, the steam outlet end is connected with the vacuum pump and the hot well respectively, a vacuum degree sensor is arranged between the steam outlet end and the vacuum pump, a liquid level sensor is arranged on the hot well, the vacuum pump is communicated with the atmosphere, the hot well is connected with a water tank through the condensate pump, a total valve is arranged between the hot well and the condensate pump, an electromagnetic valve, a check valve and a flow sensor are arranged between the condensate pump and the water tank; the two ends of the cold fluid channel are connected with a heating system, a filter is arranged on the water inlet end of the cold fluid channel, a circulating water pump is arranged on the pipeline of the water inlet end, a temperature sensor, a flow sensor and a pressure sensor are arranged between the circulating water pump and the water inlet end, and all the temperature sensors, flow sensors, pressure sensors, vacuum degree sensors, liquid level sensors, electromagnetic valves, electric vacuum valves, condensate pumps and vacuum pumps are electrically connected with a control system.

[0007] Further, the heat exchanger is one or a combination of a tube-shell heat exchanger, a plate heat exchanger or a fin heat exchanger.

[0008] Further, the steam inlet end of the hot fluid channel is provided with a dust collector.

[0009] Further, a total valve is arranged between the steam outlet end of the hot fluid channel and the vacuum degree sensor.

[0010] Further, the upstream end and / or the downstream end of the vacuum pump, the condensate pump and the circulating water pump are provided with control valves.

[0011] Further, the vacuum pump, the condensate pump and the circulating water pump are each provided with two parallel and identical sets, the control valves are arranged on the branch lines, and the electromagnetic valve arranged between the condensate pump and the water tank is arranged on the main line.

[0012] Further, temperature sensors and pressure sensors are arranged on the downstream pipeline of the cold fluid channel, and the temperature sensors and the pressure sensors are electrically connected with the control system.

[0013] Further, an air cooler is further included, and the air cooler is arranged opposite to the vacuum pump.

[0014] All the total valves can be electrically connected with the control system or manually controlled.

[0015] The utility model discloses the beneficial effect is:

[0016] (1) The vacuum pump group can effectively extract the air inside the condenser to make the vacuum degree slightly lower than the production system (i.e. the evaporator system), so that the exhaust steam can be self-sucked into the condenser to start heat exchange, and the exhaust steam inside the condenser is liquefied to further form a certain vacuum, thereby ensuring the continuous operation of the system, and the liquefied condensed water enters the thermal well and is discharged by the condensate pump. The air-cooled machine can ensure that the water temperature in the water tank of the vacuum pump is constant and at a low temperature, so as to ensure that the vacuum pump operates normally, avoid the influence of the rising water temperature caused by long-time operation on the internal vacuum of the condenser, and ensure that the internal vacuum of the condenser is always maintained within the required range;

[0017] (2) The heating water is used as a cold fluid, and the circulating water pump provides power to heat the households in the living area. The cold fluid system connects the condenser and the distribution and collection tank for heating the residents by the circulating water pump, forms a closed loop, and uses the circulating water to bring the exhaust steam heat to the residents' homes, and the cooled circulating water can absorb more exhaust steam heat to realize efficient utilization of the exhaust steam.

[0018] (3) The temperature control system of the utility model is used for monitoring and controlling the temperature of the cold fluid before and after heat exchange in the exhaust steam utilization system. The temperature control system includes various temperature sensors, which adjust the flow of the cold fluid, the amount of exhaust steam, etc. according to the monitoring signals of the temperature sensors, so that the overall system is maintained in a high heat exchange efficiency state, and the loss or incomplete utilization of exhaust steam heat is avoided as much as possible. BRIEF DESCRIPTION OF DRAWINGS

[0019] The embodiments of the utility model will be further described below with reference to the drawings, in which:

[0020] Figure 1 The system structure schematic diagram of the utility model is shown.

[0021] Among them, 1, electromagnetic valve;2, total valve;3, control valve;4, vacuum pump;5, condensate pump;6, circulating water pump;7, temperature sensor;8, vacuum degree sensor;9, liquid level sensor;10, flow sensor;11, pressure sensor;12, filter;13, electric vacuum valve;14, check valve, the arrow is the flow direction of liquid or gas. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical scheme and advantages of the utility model more clear and obvious, the utility model will be further described in detail below with reference to the drawings through specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the utility model, and are not used to limit the utility model.

[0023] Taking the evaporation process of the alumina production industry as an example:

[0024] The sodium aluminate solution in evaporation process of alumina production is heated by high temperature and high pressure steam to obtain enough heat to make the water in it overflow as steam, which is timely removed by vacuum method, so that the steam produced in the concentration process of mother liquor is used as the next level heat source. The concentrated mother liquor is further concentrated and part of the heat is recovered by flash evaporation and pressure reduction, and finally the steam is treated by water cooler, and the heat is dissipated into the atmosphere. Although the steam contains a large amount of heat energy, due to its low temperature and pressure, the traditional energy-saving technology cannot recover and utilize it with reasonable process parameters and relatively low engineering cost. Although the temperature of the steam is not high, there is still a large space for use, especially when the ambient temperature is low (such as winter), the steam and the environment have a large temperature difference, which provides the basis for the utilization of steam waste heat.

[0025] The vacuum degree of the steam in the evaporator of the production system is 0.088-0.090 MPa, the temperature can reach 58-60℃, the steam quantity is 40-50 t / h, and the heat loss is considerable. According to the estimate, the sufficient steam at 60℃ can raise the temperature of the cold fluid to 56-57℃, the steam of 20 t / h can raise the temperature of the circulating water of 800 m 3 / h by 10℃. The circulating water at 56-57℃ has slightly limited use in production, but it can meet the needs of residential heating in winter.

[0026] In one embodiment, a kind of evaporator exhaust steam utilization system, including evaporator, condenser, hot well, two groups of parallel vacuum pump 4, two groups of parallel condensate pump 5, two groups of parallel circulating water pump 6 and air cooling machine (not shown in the drawing), air cooling machine is opposite vacuum pump 4 arrangement, circulating water pump provides conveying power, condensate pump provides the external discharge conveying power for hot well condensate.Evaporator outlet is connected with the steam inlet of condenser, and electric vacuum valve 13 is arranged between the steam outlet and the steam inlet;Condenser is provided with heat exchanger, and the plate heat exchanger or spiral pipe heat exchanger with large heat exchange area and superior heat exchange performance is selected, if circulating water needs to be raised to a higher temperature, lithium bromide solution can be added to recycle the heat of exhaust steam driven by new steam.The material of heat exchange pipe is stainless steel or copper alloy, and the heat exchanger includes cold fluid passage and hot fluid passage, the steam inlet end of hot fluid passage is connected with the steam inlet, the gas outlet end is connected with vacuum pump 4 and hot well respectively, and total valve 2 and vacuum degree sensor 8 are sequentially arranged on the total road between the gas outlet end and vacuum pump branch, the branch is sequentially controlled valve 3 and vacuum pump 4, and then is communicated with the atmosphere;Liquid level sensor 9 is arranged on the hot well, the hot well is connected with water tank through condensate pump 5, total valve 2 is arranged on the total road between the hot well and condensate pump 5, controlled valve 3, condensate pump 5 and controlled valve 3 are sequentially arranged on each branch, then two branches are combined into a total road, electromagnetic valve 1, check valve 14, flow sensor 10 and water tank are sequentially arranged on the total road;Both ends of cold fluid passage are connected with heating system, filter 12 is arranged on the water inlet end of cold fluid passage, circulating water pump 6 is arranged on the pipeline of water inlet end, temperature sensor 7, flow sensor 10 and pressure sensor 11 are arranged on the total road between circulating water pump 6 and water inlet, and one circulating water pump 6 and two controlled valves 3 before and after are arranged on the branch of circulating water pump. That is, controlled valve 3 is arranged on the upstream end of the branch of vacuum pump 4, condensate pump 5 and circulating water pump 6, controlled valve 3 is also arranged on the downstream end of the branch of condensate pump 5 and circulating water pump 6, electromagnetic valve 1 is also arranged on the total road of condensate pump 5, and all electromagnetic valves 1 and electric vacuum valve 13 are electrically connected with control system.All temperature sensors 7, flow sensors 10, vacuum degree sensors 8, liquid level sensors 9 and pressure sensors 11 are electrically connected with control system.

[0027] Wherein, the vacuum pump group vacuum value should not be less than the production system, should reach 0.09 mpa or more, namely when the vacuum value sensor 8 shows the number is less than 0.09 mpa, start or improve the power of vacuum pump, if still no improvement, should switch vacuum pump branch. In addition, the filter and dust collector in the system can filter impurities on the inlet water end and inlet steam end, to prolong the service life and effect of heat exchanger. Pump set is provided with two sets of one spare one use, when the vacuum degree sensor on the vacuum pump pipeline shows abnormal, can switch the vacuum pump on the other branch, close the vacuum pump used previously, when the flow sensor or pressure sensor in the circulating water shows abnormal, can switch the circulating water pump or open double branch, when the liquid level sensor of the hot well shows abnormal high, and has opened the condensate pump, can simultaneously open the condensate pump on the other branch, when the flow sensor between the condensate pump and water tank is abnormal, can switch the condensate pump branch.

[0028] Before the whole system runs, the total valve 2 between the hot well and the condensate pump is closed, and the electromagnetic valve 1 in the condensate pipe is set, so that the condensate system is consistent with the internal vacuum pump of the condenser, to avoid the problem of net positive suction head causing the water to be not pumped or the equipment to be damaged. After starting heat exchange, open the total valve 2 between the hot well and the condensate pump and the control valve 3 before and after the condensate pump, when the liquid level sensor shows a higher value than the set value, automatically open the electromagnetic valve 1 between the water tank and the condensate pump, and start the condensate pump to pump away the condensate in the hot well. When the temperature sensor in the circulating water pipeline shows a higher temperature, the automatic control system can be used to control the vacuum pump to reduce the power of vacuum pumping or adjust the opening degree of the electric vacuum valve 13 between the evaporator and the condenser, to control the condenser to maintain a certain vacuum degree while appropriately reducing the exhaust steam entering, or to control the total valve 2 or control valve 3 on the circulating water pipeline to increase the opening degree, to increase the flow of heating water and fully utilize the heat of exhaust steam, when the temperature sensor in the circulating water pipeline shows a lower temperature, the above adjustment is opposite.

[0029] The evaporator in the utility model is the evaporator of the evaporation process in the alumina production industry, a high-temperature-resistant and corrosion-resistant pipeline is welded at a suitable position on the pipeline through which the last-effect exhaust steam enters the water cooler to connect the condenser and the evaporator, and the electric vacuum valve 13 is used to control the opening and closing. During the pipeline connection process, it is ensured that the pipeline interface is sealed well and there is no risk of exhaust steam leakage. Before installation, the pipeline is strictly purged and cleaned to remove internal impurities and prevent them from affecting the heat exchange efficiency and the safe operation of the equipment.

[0030] In addition, the control system needs to be calibrated regularly, the measurement range and accuracy of each sensor are set before use, and the control threshold values of temperature, pressure, flow and other parameters are set according to the operation requirements of the system. The control system is electrically connected with each actuator (such as valve motor, pump, etc.) and is communicated and debugged to ensure that the control system can accurately receive the sensor signals and timely issue control instructions.

[0031] The process of the utility model reduces the waste heat dissipation of the evaporator, reduces water consumption and power consumption, improves the heating temperature in winter at home, and has obvious technical advantages and economic advantages.

[0032] The above describes some example embodiments of the utility model, and it can be understood that the above embodiments are only used for explaining the utility model and do not constitute the limitation on the protection scope of the utility model. The features in these embodiments can be recombined in a suitable mode, and the scheme obtained thereby is still within the protection scope required by the utility model. Based on the above embodiments, all other embodiments obtained by the person skilled in the art without making creative labor, namely all modifications, equivalent replacement and improvement etc. made within the spirit and principle of the application, are within the protection scope required by the utility model.

Claims

1. An evaporator exhaust steam utilization system characterized by, The application relates to a heat exchange system, which comprises an evaporator, a condenser, a hot well, a vacuum pump (4), a condensate pump (5) and a circulating water pump (6), wherein the steam outlet of the evaporator is connected with the steam inlet of the condenser, an electric vacuum valve (13) is arranged between the steam outlet and the steam inlet; a heat exchanger is arranged in the condenser, the heat exchanger comprises a cold fluid channel and a hot fluid channel, the steam inlet end of the hot fluid channel is connected with the steam inlet, the steam outlet end is connected with the vacuum pump (4) and the hot well respectively, a vacuum degree sensor (8) is arranged between the steam outlet end and the vacuum pump, a liquid level sensor (9) is arranged on the hot well, the vacuum pump (4) is communicated with the atmosphere, the hot well is connected with a water tank through the condensate pump (5), a total valve (2) is arranged between the hot well and the condensate pump (5), an electromagnetic valve (1), a check valve (14) and a flow sensor (10) are arranged between the condensate pump (5) and the water tank; the two ends of the cold fluid channel are connected with a heating system, a filter (12) is arranged at the water inlet end of the cold fluid channel, a circulating water pump (6) is arranged on the pipeline at the water inlet end, a temperature sensor (7), a flow sensor (10) and a pressure sensor (11) are arranged between the circulating water pump (6) and the water inlet end, all the temperature sensor (7), the flow sensor (10), the pressure sensor (11), the vacuum degree sensor (8), the liquid level sensor (9), the electromagnetic valve (1), the electric vacuum valve (13), the condensate pump (5) and the vacuum pump (4) are electrically connected with a control system.

2. The evaporator exhaust vapor utilization system of claim 1, wherein, The heat exchanger is one or a combination of a tube-shell heat exchanger, a plate heat exchanger or a fin heat exchanger.

3. The evaporator exhaust vapor utilization system of claim 1, wherein, A dust remover is arranged at the steam inlet end of the hot fluid channel.

4. The evaporator exhaust vapor utilization system of claim 1, wherein, A total valve (2) is arranged between the steam outlet end of the hot fluid channel and the vacuum degree sensor (8).

5. The evaporator exhaust vapor utilization system of claim 1, wherein, Control valves (3) are arranged at the upstream end and / or downstream end of the vacuum pump (4), the condensate pump (5) and the circulating water pump (6).

6. A system for utilizing evaporator exhaust steam according to claim 5, wherein The vacuum pump (4), the condensate pump (5) and the circulating water pump (6) are provided with two sets of parallel and identical devices, all the control valves (3) are arranged on the branch lines, and the electromagnetic valve (1) arranged between the condensate pump (5) and the water tank is arranged on the main line.

7. The evaporator exhaust vapor utilization system of claim 1, wherein, Temperature sensors (7) and pressure sensors (11) are also arranged on the downstream pipeline of the cold fluid channel, and the temperature sensors (7) and the pressure sensors (11) are electrically connected with the control system.

8. The evaporator exhaust vapor utilization system of claim 1, wherein, An air cooler is arranged opposite to the vacuum pump (4).

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