阅读说明：本技术 一种制氧工序余热回收利用系统及方法 (System and method for recycling waste heat in oxygen production process ) 是由 徐伟 倪健勇 马光宇 刘冬杰 武吉 陈鹏 王永 胡绍伟 张天赋 王东山 于 2019-09-04 设计创作，主要内容包括：本发明涉及钢铁行业节能技术领域,尤其涉及一种制氧工序余热回收利用系统及方法。包括空压机一级压缩、空压机二级压缩、空压机三级压缩、一级换热器、二级换热器、三级换热器、制氧机、制冷用户、供热用户、1#热泵机组、2#热泵机组、冷却塔、给水池、高温蓄水槽、低温液体换热器、流量计和以上设备之间连接的各种阀门。制氧工序余热回收利用方法包含两种运行模型,一是低温换热器非运行模式,二是低温换热器运行模式。本发明对空压机冷却水余热进行直接高效利用,解决了低温液氧加热存在的非计划、间歇式及瞬间加热量大的问题,实现了制氧工序余热在生产、生活中的有效利用。提高系统余热利用效率,具有节约能源、降低维护成本等特点。(The invention relates to the technical field of energy conservation in the steel industry, in particular to a system and a method for recycling waste heat in an oxygen production process. The system comprises an air compressor primary compression device, an air compressor secondary compression device, an air compressor tertiary compression device, a primary heat exchanger, a secondary heat exchanger, a tertiary heat exchanger, an oxygen generator, a refrigeration user, a heat supply user, a 1# heat pump unit, a 2# heat pump unit, a cooling tower, a water supply tank, a high-temperature water storage tank, a low-temperature liquid heat exchanger, a flow meter and various valves connected among the devices. The method for recycling the waste heat in the oxygen generation process comprises two operation models, namely a non-operation mode of the low-temperature heat exchanger and an operation mode of the low-temperature heat exchanger. The invention directly and efficiently utilizes the waste heat of the cooling water of the air compressor, solves the problems of unplanned, intermittent and instant heating quantity of low-temperature liquid oxygen heating, and realizes the effective utilization of the waste heat of the oxygen production process in production and life. The waste heat utilization efficiency of the system is improved, and the system has the characteristics of saving energy, reducing maintenance cost and the like.)

1. The system for recycling the waste heat in the oxygen production process is characterized by comprising an air compressor primary compression device, an air compressor secondary compression device, an air compressor tertiary compression device, a primary heat exchanger, a secondary heat exchanger, a tertiary heat exchanger, an oxygen generator, a refrigeration user, a heat supply user, a 1# heat pump unit, a 2# heat pump unit, a cooling tower, a water supply tank, a high-temperature water storage tank, a low-temperature liquid heat exchanger, a flow meter and a valve;

The primary compression of the air compressor, the air side of the primary heat exchanger, the secondary compression of the air compressor, the air side of the secondary heat exchanger, the tertiary compression of the air compressor, the air side of the tertiary heat exchanger and the oxygen generator are connected in series;

The water side outlet of the first-stage heat exchanger is connected with the inlet of the No. 1 heat pump unit and is connected with the inlet of a heat supply user in a parallel mode; the water side outlet of the second-stage heat exchanger and the water side outlet of the third-stage heat exchanger are connected with a refrigerating user inlet; the refrigerating user outlet is connected with the inlet of the high-temperature water storage tank;

The outlet of the heat pump unit 1 is connected with the inlet of the high-temperature water storage tank, and the outlet of the heat source driven by the heat pump unit 1 is connected with the inlet of the cooling tower; the outlet of the high-temperature water storage tank is also connected with the inlet of the low-temperature liquid heat exchanger and the inlet of the heat supply user in parallel; the outlet of the heat supply user is respectively connected with the inlet of a heat source and the inlet of a cooling tower driven by the 2# heat pump unit in a parallel mode;

the outlet of the low-temperature liquid heat exchanger is respectively connected with the driving heat source inlet of the No. 1 heat pump unit, the No. 2 heat pump unit inlet and the cooling tower inlet in a parallel mode; the outlet of the 2# heat pump unit is connected with the inlet of a heat supply user, and the outlet of a heat source driven by the 2# heat pump unit is connected with the inlet of a cooling tower;

The outlet of the cooling tower is connected with the inlet of the water supply pool through a flowmeter, and is converged with the outlet of the water supply pool and connected with the water side inlets of the first-stage heat exchanger, the second-stage heat exchanger and the third-stage heat exchanger; the feedback signal of the flowmeter is connected with the water supply pool to control the inlet and outlet switch regulating valve of the water supply pool.

2. The method for recycling the waste heat of the oxygen production process based on the system of claim 1 is characterized by comprising two operation models, namely a non-operation mode of the low-temperature heat exchanger and an operation mode of the low-temperature heat exchanger;

1) Non-operation mode of the low-temperature heat exchanger:

The normal temperature and normal pressure air is subjected to primary compression by an air compressor, the compressed air is at the temperature of 70-100 ℃, the air enters a primary heat exchanger to exchange heat with cooling water, the compressed air after heat exchange and cooling enters the air compressor for secondary compression and the air compressor for tertiary compression, the temperature of the secondary compressed air and the temperature of the tertiary compressed air reach 100-120 ℃, the air after compression enters a secondary heat exchanger and a tertiary heat exchanger to exchange heat, and finally the air after tertiary compression and cooling enters an oxygen generator; setting the water storage capacity of the high-temperature water storage tank to 1500Nm³～2000Nm³；

The cooling water entering the primary heat exchanger is subjected to heat exchange and then enters an inlet of a heat supply user, wherein the temperature of the cooling water is 55-65 ℃; after the cooling water entering the secondary heat exchanger and the tertiary heat exchanger is heated to 80-90 ℃ through heat exchange, the cooling water enters a refrigeration user to serve as a heat source to drive a lithium bromide refrigeration unit, and cold energy is generated to be required by the user;

after the lithium bromide unit is driven to refrigerate, the temperature of hot water is reduced to 70-75 ℃, and the hot water flows out and enters a high-temperature water storage tank; wherein 30-60% of hot water flows out of the high-temperature water storage tank and low-temperature water with the temperature of 55-65 ℃ from the primary heat exchanger are gathered as hot water to enter heat supply users, and the rest 40-70% of hot water is left in the high-temperature water storage tank;

After heat supply, the water temperature is reduced to 40-50 ℃, the water flows out of a heat supply user, enters a cooling tower to be cooled to 30-35 ℃, flows out of a switch valve and is reused as cooling water of an air compressor through a flowmeter;

After the system operates for 25-35 hours, adjusting the water outlet quantity of the high-temperature water storage tank, wherein 100% of hot water at 70-75 ℃ entering the high-temperature water storage tank flows out of the high-temperature water storage tank and low-temperature water at 55-65 ℃ coming out of the primary heat exchanger are gathered to be used as hot water to enter heat supply users;

The temperature of the return water of the heat supply user is reduced to 40-50 ℃, the return water flows out, and the return water enters a cooling tower to be cooled to 30-35 ℃ for recycling; the flow meter detects the amount of return water, and when the amount of return water is lower than 2-5% of the total amount, the return water is fed back to a switch regulating valve of the water supply tank for water supplement;

2) The operation mode of the low-temperature heat exchanger is as follows:

A. under the condition that the flow of hot water required by the operation of the low-temperature heat exchanger is lower than the sum of the flow of cooling water of the secondary heat exchanger and the flow of cooling water of the tertiary heat exchanger, the temperature of the cooling water entering the primary heat exchanger after heat exchange is 55-65 ℃, and the cooling water enters an inlet of a heat supply user; after the cooling water entering the secondary heat exchanger and the tertiary heat exchanger is heated to 80-90 ℃ through heat exchange, the cooling water enters a refrigeration user to serve as a heat source to drive a lithium bromide refrigeration unit, and cold energy is generated to be required by the user;

After the lithium bromide unit is driven to refrigerate, the temperature of hot water is reduced to 70-75 ℃, the hot water flows out of a refrigeration user and enters a high-temperature water storage tank, the high-temperature water storage tank provides the required hot water at 70-75 ℃ for a low-temperature liquid heat exchanger, the hot water is cooled to 45-50 ℃ after heat exchange, and the hot water flows out of the low-temperature liquid heat exchanger and enters a cooling tower; meanwhile, the flow of hot water supplied to heat supply users by the high-temperature water storage tank can be adjusted, the adjustment range is 80% -100% of the water inlet flow of the high-temperature water storage tank, and the hot water is gathered with low-temperature water from the primary heat exchanger and supplied to the heat supply users; feeding back signals to a water system through a flowmeter, introducing redundant water supply into a water supply pool through a water supply system control switch regulating valve, storing water for a high-temperature water storage tank after the operation mode of a low-temperature heat exchanger is finished until the water amount in the high-temperature water storage tank is increased to 1500Nm³～2000Nm³；

B. under the condition that the hot water flow required by the operation of the low-temperature heat exchanger is higher than the cooling water flow sum of the secondary heat exchanger and the tertiary heat exchanger and is lower than the cooling water flow sum of the primary heat exchanger, the secondary heat exchanger and the tertiary heat exchanger, the temperature of the cooling water entering the primary heat exchanger is 55-65 ℃ after heat exchange, and the cooling water enters the inlet of a No. 1 heat pump unit;

after the cooling water entering the secondary heat exchanger and the tertiary heat exchanger is heated to 80-90 ℃ through heat exchange, the cooling water enters a refrigeration user to serve as a heat source to drive a lithium bromide refrigeration unit, and cold energy is generated to be required by the user; after the lithium bromide unit is driven to refrigerate, the temperature of hot water is reduced to 70-75 ℃, and the hot water flows out of a refrigeration user and enters a high-temperature water storage tank; the high-temperature water storage tank provides required hot water at 70-75 ℃ to the low-temperature liquid heat exchanger to heat the low-temperature liquid oxygen, so that the temperature of the low-temperature liquid oxygen is raised to 20 ℃ and the low-temperature liquid oxygen enters an oxygen pipe network;

After heat exchange, the low-temperature water cooled to 45-50 ℃ flows out of the low-temperature liquid heat exchanger, wherein 15-25% of the low-temperature water is taken as a driving heat source to enter a No. 1 heat pump unit, and is cooled to 35-40 ℃ after passing through the No. 1 heat pump unit, and flows out of a driving heat source outlet to enter a cooling tower; 50-70% of low-temperature water calculated by the flow ratio enters a No. 2 heat pump unit for heating, and the water is heated to 55-60 ℃ and enters a heat supply user for heat supply; the rest 15 to 25 percent of low-temperature effluent water in terms of flow ratio enters a cooling tower; the heat exchange water with the temperature of 55-65 ℃ from the first-stage heat exchanger enters a No. 1 heat pump unit to be heated to 70-75 ℃, and flows out to enter a high-temperature water storage tank;

adjusting the flow of hot water at 70-75 ℃ supplied to a heat supply user according to the water quantity of an inlet and an outlet of the high-temperature water storage tank, wherein the adjustment range is 0-60% of the water inlet flow of the high-temperature water storage tank, and the water inlet flow of the high-temperature water storage tank is ensured to be less than or equal to the water outlet flow; the high-temperature water storage tank supplies 70-75 ℃ hot water for heat supply users and the No. 2 heat pump unit heats the water to 55-60 ℃, the water is converged and flows into the heat supply users for heat supply, and the water temperature is reduced to 40-50 ℃ after heat supply and flows out of the heat supply users; wherein 50-75% of low-temperature water is used as a driving heat source to enter a No. 2 heat pump unit, and is cooled to 35-40 ℃ after being driven to enter a cooling tower through a switch valve; the rest 25 to 50 percent of low-temperature water directly enters a cooling tower and is recycled after being cooled;

Feeding back signals to a water system through a flowmeter, and introducing redundant water supply into a water supply pool through a control switch regulating valve of the water supply system; and after the operation mode of the low-temperature heat exchanger is finished, the oxygen generator is recovered to operate, and the water storage amount in the high-temperature water storage tank is reduced. Meanwhile, the system is switched from the low-temperature heat exchanger operation mode to the low-temperature heat exchanger non-operation mode to store water for the high-temperature water storage tank until the water amount in the high-temperature water storage tank is increased to 1500Nm³～2000Nm³For the next time of low temperature heat exchanger operation.

Technical Field

The invention relates to the technical field of energy conservation in the steel industry, in particular to a system and a method for recycling waste heat in an oxygen production process.

background

Iron and steel enterprises need a large amount of energy media such as high-purity oxygen, nitrogen and the like in the smelting production process, so that large iron and steel enterprises usually have an oxygen production process, and are provided with a plurality of oxygen generators and oxygen pipe networks, and oxygen produced by the oxygen generators is sent to each oxygen consuming user through the pipe networks; when a trip fault occurs in a certain oxygen generator in the oxygen generation process and the amount of generated oxygen cannot meet the requirements of downstream oxygen consumption users, the pressure of an oxygen pipe network is insufficient, and the trip fault of the oxygen generator generally needs 15-20 hours to recover; in order to ensure stable production of downstream oxygen consuming users, a production plant is generally provided with a plurality of liquid oxygen tanks for storing a large amount of liquid oxygen, when the pressure of an oxygen pipe network is insufficient, the liquid oxygen stored in the liquid oxygen tanks for later use can be heated into normal-temperature gas to be conveyed into the oxygen pipe network, namely, the liquid oxygen is heated from minus 183 ℃ to 20 ℃ by a heat source heating mode and is conveyed into the pipe network to be supplied to the oxygen consuming users. Because the heating of the low-temperature liquid oxygen belongs to unplanned and intermittent heating, and the instant heating quantity is large; at present, most domestic oxygen plants adopt a water bath type heat exchange mode to heat liquid oxygen, a heating heat source is generally steam, the heating mode can consume a large amount of high-quality energy, and the production cost of enterprises is increased.

a plurality of air compressors are arranged in the oxygen production process; when the air compressor is in operation, the air compressor is really used for increasing the electric energy consumed by air potential energy, and only occupies a small part, about 15%, of the total electric energy consumption. About 85% of the electricity consumed is converted to heat in the compressed gas and is discharged to the air by air or water cooling. If the waste heat of the compressed gas is recovered and is used for the production and living heat supply of the oxygen process nearby, the energy utilization efficiency can be improved, and the enterprise cost can be reduced; meanwhile, the method is also beneficial to reducing the coal burning quantity and reducing the pollution of the coal to the environment.

At present, a plurality of researches and applications are developed aiming at the recovery and utilization of the waste heat of an air compressor in an oxygen production process. Through searching for new, some related patents are searched, for example, patent CN106762557A discloses an intelligent hot water supply device based on air compressor waste heat recovery; according to the invention, intelligent hot water supply is realized by adding the cache heat storage equipment between the heat exchanger and a hot user. Although the method realizes the stability of the heat supply system, the heat loss of the system is larger due to excessive intermediate heat exchange and heat storage equipment. Patent CN108150422A discloses an air compressor waste heat recycling system, which drives a lithium bromide absorption type water chilling unit to produce cold water in a hot water manner by recycling air compressor waste heat; however, the hot water (generally at about 70-75 ℃) after driving the lithium bromide absorption type water chilling unit is not utilized, so that the energy utilization rate is low. Patent CN107178934A discloses an air compressor waste heat deep recycling system, in which three-stage compression of the air compressor is performed by three-stage heat exchange, and high-temperature water after heat exchange enters a waste heat extraction device and is converted into high-temperature waste heat water after heat exchange again, and the high-temperature waste heat water enters the waste heat deep recycling system; the system does not solve the problems that the air temperature is lower after the primary compression of the air compressor and the waste heat cannot be effectively utilized after being recovered.

In conclusion, the system and the method for recycling the waste heat in the oxygen production process have some problems. The system and the method mainly reflect that the existing system and method for utilizing the waste heat of the air compressor in the oxygen production process do not consider that the temperature of air is low after the primary compression of the air compressor is actually operated, and the air cannot be effectively utilized after the waste heat is recovered; meanwhile, no solution is provided for how to effectively adapt to the fluctuation of the demand of the heat user for the waste heat recovery of the air compressor. And the waste heat resources of the oxygen production process are mainly used for domestic heat supply after being recovered, and the domestic heat supply is usually limited by heat supply quantity and heat supply radius, so that a large amount of waste heat resources of the oxygen production process cannot be fully utilized. Therefore, it is necessary to search for a more practical and effective system and method for recycling the waste heat of the oxygen production process, so that the waste heat of the oxygen production process can be fully used for production and living heat supply of the oxygen process nearby.

Disclosure of Invention

in order to overcome the defects of the prior art, the invention provides a system and a method for recycling waste heat in an oxygen production process. The waste heat of the oxygen production process can be fully used for production and living heat supply of the oxygen process nearby, and the waste heat of the air compressor is utilized to effectively adapt to demand fluctuation of a heat user.

in order to achieve the purpose, the invention adopts the following technical scheme:

the utility model provides an oxygen making process waste heat recovery utilizes system includes air compressor machine one-level compression, air compressor machine second grade compression, air compressor machine tertiary compression, one-level heat exchanger, second grade heat exchanger, tertiary heat exchanger, oxygenerator, refrigeration user, heat supply user, 1# heat pump set, 2# heat pump set, cooling tower, water-feeding pond, high temperature catch basin, low temperature liquid heat exchanger, flowmeter and the various valves of being connected between above equipment.

wherein air compressor machine one-level compression export and one-level heat exchanger gas side entry linkage, one-level heat exchanger gas side export and air compressor machine second grade compression entry linkage, air compressor machine second grade compression export and second grade heat exchanger gas side entry linkage, second grade heat exchanger gas side export and air compressor machine tertiary compression entry linkage, air compressor machine tertiary compression export and tertiary heat exchanger gas side entry linkage, tertiary heat exchanger gas side export and oxygenerator entry linkage.

The water side outlet of the first-stage heat exchanger is connected with the inlet of the No. 1 heat pump unit through a switch regulating valve, and is connected with the inlet of a heat supply user through a switch valve in a parallel mode; the water side outlet of the second-stage heat exchanger and the water side outlet of the third-stage heat exchanger are connected with a refrigerating user inlet through a switch valve; the refrigerating user outlet is connected with the inlet of the high-temperature water storage tank; the outlet of the 1# heat pump unit is connected with the inlet of the high-temperature water storage tank through a switch valve, and the outlet of the 1# heat pump unit driving heat source is connected with the inlet of the cooling tower through the switch valve; the outlet of the high-temperature water storage tank is connected with the inlet of the low-temperature liquid heat exchanger and the inlet of the heat supply user respectively through the switch valve in a parallel mode.

The outlet of the heat supply user is connected with the inlet of the heat source and the inlet of the cooling tower in parallel by a switch regulating valve and a switch valve respectively, wherein the inlet of the heat source is driven by a 2# heat pump unit; the outlet of the low-temperature liquid heat exchanger is connected with the driving heat source inlet of the No. 1 heat pump unit, the inlet of the No. 2 heat pump unit and the inlet of the cooling tower through a switch regulating valve and a switch valve respectively in a parallel mode; the outlet of the 2# heat pump unit is connected with the inlet of a heat supply user through a switch valve, and the outlet of the 2# heat pump unit drives the heat source to be connected with the inlet of the cooling tower through the switch valve.

The outlet of the cooling tower is connected with the inlet of the water supply pool through a flow meter and a switch regulating valve, and is converged with the outlet of the water supply pool and connected with the water side inlets of the first-stage heat exchanger, the second-stage heat exchanger and the third-stage heat exchanger; the feedback signal of the flowmeter is connected with the water supply pool to control the inlet and outlet switch regulating valve of the water supply pool.

the method for recycling the waste heat in the oxygen production process comprises two operation models, namely a non-operation mode of the low-temperature heat exchanger and an operation mode of the low-temperature heat exchanger.

Non-operation mode of the low-temperature heat exchanger:

For 10 ten thousand Nm³H to 20 ten thousand Nm³the air at normal temperature and normal pressure is subjected to primary compression by an air compressor to reach 70-100 ℃, enters a primary heat exchanger to exchange heat with cooling water at 30-35 ℃, enters the air compressor to be subjected to secondary compression and tertiary compression by the air compressor to reach 100-120 ℃ after the heat exchange, enters a secondary heat exchanger and a tertiary heat exchanger to exchange heat after the compression, and finally enters the oxygen generator after the tertiary compression and the cooling. The water storage capacity of the high-temperature water storage tank is designed to be 1500Nm³～2000Nm³and the water storage capacity can meet the water quantity required by the operation of the low-temperature liquid heat exchanger for one time.

The cooling water entering the primary heat exchanger is subjected to heat exchange, then the temperature of the cooling water is 55-65 ℃, and the cooling water enters an inlet of a heat supply user through a switch valve; after the cooling water entering the secondary heat exchanger and the tertiary heat exchanger is heated to 80-90 ℃ through heat exchange, the cooling water enters a refrigeration user through a switch valve to serve as a heat source to drive a lithium bromide refrigeration unit, and the cooling energy is generated to be required by the user.

After the lithium bromide unit is driven to refrigerate, the temperature of the hot water is reduced to 70-75 ℃, and the hot water flows out of a refrigeration user and enters a high-temperature water storage tank. 30-60% (flow ratio) of the 70-75 ℃ hot water entering the high-temperature water storage tank flows out of the high-temperature water storage tank, the low-temperature water with the temperature of 55-65 ℃ which flows out of the first-stage heat exchanger and the switch regulating valve are converged to be used as hot water to enter a heat supply user, and the rest 40-70% (flow ratio) of the 70-75 ℃ hot water is left in the high-temperature water storage tank; after heat supply, the water temperature is reduced to 40-50 ℃ and flows out of a heat supply user, the water enters a cooling tower through a switch valve and is cooled to 30-35 ℃, and the water flows out of the switch valve and passes through a flowmeter to be reused as cooling water of an air compressor for recycling; because 40-70% (flow ratio) of hot water is left in the high-temperature water storage tank, the water supply tank needs to be supplemented with water in an equivalent amount through a switch regulating valve; the heat supply users belong to low-load operation in the operation process.

1500Nm after 25-35 hours of system operation³～2000Nm³the water storage amount in the high-temperature water storage tank can meet the water amount required by the low-temperature liquid heat exchanger in one-time operation; adjusting the water outlet quantity of the high-temperature water storage tank, wherein 100 percent of hot water at 70-75 ℃ entering the high-temperature water storage tank flows out of the high-temperature water storage tank and low-temperature water at 55-65 ℃ coming out of the primary heat exchanger are gathered to be used as hot water to enter heat supply users; after the circulation operation, the amount of hot water supplied to a heat supply user reaches a stable state, and the operation belongs to normal load operation; and the water storage capacity in the high-temperature water storage tank can completely meet the water quantity required by the low-temperature liquid heat exchanger in one-time operation, and the water inlet and outlet capacity of the high-temperature water storage tank is balanced.

The temperature of the return water of a heat supply user is reduced to 40-50 ℃ and flows out, the return water enters a cooling tower through a switch valve and is cooled to 30-35 ℃, and the return water flows out of the switch valve and is reused as cooling water of an air compressor through a flowmeter; the flow meter detects the return water amount, and when the return water amount is lower than 2% -5% of the total amount, the return water amount is fed back to a switch regulating valve of the water supply tank for water supplement.

the operation mode of the low-temperature heat exchanger is as follows:

For a three-stage compression air compressor unit with 10 ten thousand Nm 3/h-20 ten thousand Nm3/h, normal temperature and normal pressure air is subjected to first-stage compression by an air compressor and then reaches 70-100 ℃, enters a first-stage heat exchanger to exchange heat with cooling water with the temperature of 30-35 ℃, enters a second-stage compression stage and a third-stage compression stage of the air compressor after the heat exchange, reaches 35-40 ℃, enters the second-stage compression stage and the air compressor to perform third-stage compression, reaches 100-120 ℃, enters the second-stage heat exchanger and the third-stage heat exchanger to exchange heat after the compression, and finally enters an oxygen generator after the third-.

When a trip fault occurs in a certain oxygen generator in the oxygen generation process and the amount of produced oxygen cannot meet the requirements of downstream oxygen consumption users, the pressure of an oxygen pipe network is insufficient; the trip fault of the oxygen generator generally needs 15-20 hours to recover, in order to ensure the stable production of downstream oxygen consuming users, liquid oxygen stored in a liquid oxygen tank for later use needs to be heated into normal-temperature gas to be conveyed into an oxygen pipe network, namely the liquid oxygen is heated from 183 ℃ below zero to 20 ℃ through a low-temperature liquid heat exchanger and is sent into the pipe network; according to the oxygen amount lost due to the failure of the oxygen generator, the supplement amount required by the oxygen pipe network is 2-4 ten thousand Nm 3/h-3/h, the water amount of hot water at 70-75 ℃ required by the low-temperature liquid heat exchanger is 110-280 t/h, and the maximum time is 15-20 h. On the basis, the water storage capacity of the high-temperature water storage tank is designed to be 1500Nm 3-2000 Nm3, and the water storage capacity can meet the water quantity required by the low-temperature liquid heat exchanger in one-time operation.

Under the condition that the flow of hot water required by the operation of the low-temperature heat exchanger is lower than the sum of the flow of cooling water of the secondary heat exchanger and the flow of cooling water of the tertiary heat exchanger, the temperature of the cooling water entering the primary heat exchanger after heat exchange is 55-65 ℃, and the cooling water enters an inlet of a heat supply user through a switch valve; after the cooling water entering the secondary heat exchanger and the tertiary heat exchanger is heated to 80-90 ℃ through heat exchange, the cooling water enters a refrigeration user through a switch valve to serve as a heat source to drive a lithium bromide refrigeration unit, and the cooling energy is generated to be required by the user. After the lithium bromide unit is driven to refrigerate, the temperature of the hot water is reduced to 70-75 ℃, and the hot water flows out of a refrigeration user and enters a high-temperature water storage tank. The high-temperature water storage tank provides the requirements for the low-temperature liquid heat exchangerAfter heat exchange, the hot water with the temperature of 70-75 ℃ is cooled to 45-50 ℃ and flows out of a low-temperature liquid heat exchanger to enter a cooling tower; meanwhile, the flow of hot water supplied to heat supply users by the high-temperature water storage tank can be adjusted, the adjustment range is 80% -100% of the water inlet flow of the high-temperature water storage tank, and the hot water is gathered with low-temperature water from the primary heat exchanger and supplied to the heat supply users; after heat supply, the water temperature is reduced to 40-50 ℃ and flows out of a heat supply user, the water enters a cooling tower through a switch valve and is reduced to 30-35 ℃, and the water flows out of the cooling tower and is reused as cooling water of the air compressor through a flowmeter for recycling. Because the inflow flow of the high-temperature water storage tank is smaller than the outflow flow and has flow difference, namely the high-temperature water storage tank supplies water to the added part of the system, the total amount of circulating backwater flowing out of the cooling tower is larger than the cooling water demand of the air compressor, a signal is fed back to the water system through the flowmeter, and the control switch regulating valve of the water supply system supplies redundant water into the water supply tank. And after the operation mode of the low-temperature heat exchanger is finished, the oxygen generator is recovered to operate, and the water storage amount in the high-temperature water storage tank is reduced. Meanwhile, the system is switched from the low-temperature heat exchanger operation mode to the low-temperature heat exchanger non-operation mode to store water for the high-temperature water storage tank until the water amount in the high-temperature water storage tank is increased to 1500Nm³～2000Nm³For the next time of low temperature heat exchanger operation.

and under the condition that the hot water flow required by the operation of the low-temperature heat exchanger is higher than the cooling water flow sum of the secondary heat exchanger and the tertiary heat exchanger and is lower than the cooling water flow sum of the primary heat exchanger, the secondary heat exchanger and the tertiary heat exchanger, the system is adjusted. The cooling water entering the first-stage heat exchanger is subjected to heat exchange and then enters the inlet of the No. 1 heat pump unit through a switch valve, wherein the temperature of the cooling water is 55-65 ℃; after the cooling water entering the secondary heat exchanger and the tertiary heat exchanger is heated to 80-90 ℃ through heat exchange, the cooling water enters a refrigeration user through a switch valve to serve as a heat source to drive a lithium bromide refrigeration unit, and the cooling energy is generated to be required by the user.

After the lithium bromide unit is driven to refrigerate, the temperature of the hot water is reduced to 70-75 ℃, and the hot water flows out of a refrigeration user and enters a high-temperature water storage tank. The high-temperature water storage tank provides required hot water at 70-75 ℃ to the low-temperature liquid heat exchanger to heat the low-temperature liquid oxygen, so that the temperature of the low-temperature liquid oxygen is raised to 20 ℃ and the low-temperature liquid oxygen enters an oxygen pipe network; after heat exchange, the low-temperature water cooled to 45-50 ℃ flows out of the low-temperature liquid heat exchanger, wherein 15-25% (flow ratio) of the low-temperature water enters a No. 1 heat pump unit as a driving heat source, is cooled to 35-40 ℃ after passing through the No. 1 heat pump unit, and flows out of a driving heat source outlet to enter a cooling tower; 50-70% (flow ratio) of low-temperature water enters a No. 2 heat pump unit for heating, and flows out of a switch valve to supply heat to a heat supply user after being heated to 55-60 ℃; the rest 15-25% (flow ratio) low-temperature effluent enters a cooling tower through a switch.

the heat exchange water with the temperature of 55-65 ℃ from the first-stage heat exchanger enters a No. 1 heat pump unit to be heated to 70-75 ℃, and then flows out of a switch valve to enter a high-temperature water storage tank, and the water inlet flow of the high-temperature water storage tank is the sum of the cooling water flow of the first-stage heat exchanger, the cooling water flow of the second-stage heat exchanger and the cooling water flow of the third-stage heat exchanger; the high-temperature water storage tank can provide hot water for the low-temperature liquid heat exchanger, and can adjust the flow of hot water at 70-75 ℃ supplied to a heat supply user according to the water quantity of an inlet and an outlet of the high-temperature water storage tank, wherein the adjustment range is 0-60% of the water inlet flow of the high-temperature water storage tank, and the water inlet flow of the high-temperature water storage tank is ensured to be smaller than or equal to the water outlet flow; the high-temperature water storage tank supplies 70-75 ℃ hot water for heat supply users and the No. 2 heat pump unit heats the water to 55-60 ℃, the water is converged and flows into the heat supply users for heat supply, and the water temperature is reduced to 40-50 ℃ after heat supply and flows out of the heat supply users; wherein 50-75% of low-temperature water is used as a driving heat source to enter a No. 2 heat pump unit, and is cooled to 35-40 ℃ after being driven to enter a cooling tower through a switch valve; the rest 25-50% of low-temperature water directly enters the cooling tower through a switch valve.

Cooling to 30-35 ℃ after entering a cooling tower, and taking the water flowing out of the cooling tower as cooling water of the air compressor again for recycling through a flowmeter. Because the inflow flow of the high-temperature water storage tank is smaller than the outflow flow and has flow difference, namely the high-temperature water storage tank supplies water to the added part of the system, the total amount of circulating backwater flowing out of the cooling tower is larger than the cooling water demand of the air compressor, a signal is fed back to the water system through the flowmeter, and the control switch regulating valve of the water supply system supplies redundant water into the water supply tank. And after the operation mode of the low-temperature heat exchanger is finished, the oxygen generator is recovered to operate, and the water storage amount in the high-temperature water storage tank is reduced. And meanwhile, the system is switched from the low-temperature heat exchanger operation mode to the low-temperature heat exchanger non-operation mode, water is stored in the high-temperature water storage tank until the water amount in the high-temperature water storage tank is increased to 1500Nm 3-2000 Nm3, so that the next low-temperature heat exchanger can operate as required.

Compared with the prior art, the invention has the beneficial effects that:

The system and the method can directly and efficiently utilize the waste heat of the cooling water of the air compressor, solve the problems of unplanned, intermittent and instantaneous heating quantity of low-temperature liquid oxygen heating through the flow control of the heat source fluid and the heating fluid driven by the No. 1 heat pump unit and the No. 2 heat pump unit in the system and the method for recycling the waste heat of the oxygen generation process and the optimization design of the high-temperature water storage tank, and realize the effective utilization of the waste heat of the oxygen generation process in production and life. The waste heat utilization efficiency of the system is improved. The method has the characteristics of saving energy, reducing maintenance cost and the like.

drawings

FIG. 1 is a schematic diagram of the structure and process of the present invention.

in the figure:

1. The system comprises an air compressor primary compression device, an air compressor secondary compression device, an air compressor tertiary compression device, a 4 primary heat exchanger, a 5 secondary heat exchanger, a 6 tertiary heat exchanger, a 7 oxygen generator, a 8 refrigeration user, a 9 high-temperature water storage tank, a 10 heating user, a 11 low-temperature liquid heat exchanger, a 12 and 1 heat pump unit, a 13 and 2 heat pump unit, a 14 cooling tower, a 15 water supply tank, 16, 17, 18, 19, 21, 26, 27, 28 and 29 switch valves, 20, 22, 23, 24, 25, 30 and 31 switch regulating valves and a 32 flow meter.

Detailed Description

the invention discloses a system and a method for recycling waste heat in an oxygen production process. Those skilled in the art can modify the process parameters appropriately to achieve the desired results with reference to the disclosure herein. It is expressly intended that all such similar substitutes and modifications which would be obvious to one skilled in the art are deemed to be included in the invention. While the methods and applications of this invention have been described in terms of preferred embodiments, it will be apparent to those of ordinary skill in the art that variations and modifications in the methods and applications described herein, as well as other suitable variations and combinations, may be made to implement and use the techniques of this invention without departing from the spirit and scope of the invention.

the system for recycling the waste heat in the oxygen production process comprises an air compressor primary compression 1, an air compressor secondary compression 2, an air compressor tertiary compression 3, a primary heat exchanger 4, a secondary heat exchanger 5, a tertiary heat exchanger 6, an oxygen generator 7, a refrigeration user 8, a heat supply user 10, a 1# heat pump unit 12, a 2# heat pump unit 13, a cooling tower 14, a water supply tank 15, a high-temperature water storage tank 9, a low-temperature liquid heat exchanger 11, a flow meter 32 and various valves connected among the devices.

Wherein 1 export of air compressor machine one-level compression and 4 gas side entry linkage of one-level heat exchanger, 4 gas side exports and 2 entry linkage of air compressor machine second grade compression of one-level heat exchanger, 2 exports of air compressor machine second grade compression and 5 gas side entry linkage of second grade heat exchanger, 5 gas side exports and 3 entry linkage of air compressor machine tertiary compression, 3 exports of air compressor machine tertiary compression and 6 gas side entry linkage of tertiary heat exchanger, 6 gas side exports and 7 entry linkage of oxygenerator of tertiary heat exchanger.

The outlet of the water side of the first-stage heat exchanger 4 is connected with the inlet of the 1# heat pump unit 12 through a switch regulating valve, and is connected with the inlet of the heat supply user 10 through a switch valve in a parallel mode; the water side outlets of the secondary heat exchanger 5 and the tertiary heat exchanger 6 are connected with a refrigeration user inlet 8 through a switch valve; the outlet of the refrigeration user 8 is connected with the inlet of the high-temperature water storage tank 9; the outlet of the 1# heat pump unit 12 is connected with the inlet of the high-temperature water storage tank 9 through a switch valve, and the outlet of the heat source driven by the 1# heat pump unit 12 is connected with the inlet of the cooling tower 14 through the switch valve; the outlet of the high-temperature water storage tank 9 is also connected with the inlet of the low-temperature liquid heat exchanger 11 and the inlet of the heat supply user 10 respectively through a switch valve in a parallel mode.

the outlet of the heat supply user 10 is connected with the switch valve through a switch regulating valve in a parallel mode, and the 2# heat pump unit 13 drives the inlet of the heat source and the inlet of the cooling tower 14; the outlet of the low-temperature liquid heat exchanger 11 is connected with the driving heat source inlet of the 1# heat pump unit 12, the inlet of the 2# heat pump unit 13 and the inlet of the cooling tower 14 through a switch regulating valve and a switch valve respectively in a parallel mode. The outlet of the 2# heat pump unit 13 is connected with the inlet of a heat supply user through a switch valve, and the outlet of a heat source driven by the 2# heat pump unit 13 is connected with the inlet of a cooling tower 14 through the switch valve; an outlet of the cooling tower 14 is connected with an inlet of a water supply pool 15 through a flow meter and a switch regulating valve, and is converged with an outlet of the water supply pool 15 and connected with water side inlets of the primary heat exchanger 4, the secondary heat exchanger 5 and the tertiary heat exchanger 6; the feedback signal of the flowmeter 32 is connected with the water supply pool 15 and controls the inlet and outlet switch regulating valve of the water supply pool 15.