Multi-stage steam device utilizing waste heat recovery

Abstract

A multi-stage steam device utilizing waste heat recovery comprises a heat source, a heat exchange system and a steam preparation system. The heat exchange system comprises a waste heat exchanger and a water supplementing heat exchanger which are both communicated with a heat source, and the waste heat exchanger is communicated with the water supplementing heat exchanger through a pipeline; the steam preparation system comprises a flash tank and a steam compressor which are communicated with each other, the flash tank is connected with the waste heat exchanger in a heat exchange manner, and the flash tank is communicated with the water supplementing heat exchanger through a pipeline; the water replenishing heat exchanger is provided with a water replenishing tank which is communicated through a pipeline; compared with the prior art, by arranging the waste heat exchanger and the water supplementing heat exchanger which are communicated with each other, multi-stage heat exchange of a heat source is achieved, effective utilization of the heat source is achieved, meanwhile, the waste heat exchanger and the water supplementing heat exchanger are arranged corresponding to the circulation position of the flash tank and the water inlet position of the flash tank respectively, and multi-stage heat exchange of water flow in the flash tank is achieved; and the temperature of water flow in the flash tank is increased, so that the energy consumption required by the flash tank is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of waste heat recovery, and in particular to a multi-stage steam device utilizing waste heat recovery. Background Art

[0002] Waste heat refers to the sensible heat and latent heat that are not reasonably utilized in the original design of energy-consuming devices in industrial enterprises that have been put into operation. Waste heat includes waste heat from high-temperature exhaust gas, waste heat from cooling medium, waste heat from waste steam and waste water, waste heat from high-temperature products and slag, waste heat from chemical reactions, and waste heat from combustible waste gas, waste liquid and waste materials.

[0003] Waste heat recovery and utilization is an important way to improve economy and save fuel. The utilization of waste heat has two main functions: one is to produce low-quality steam for production and life, and the other is to produce high-pressure steam for power generation. The high-pressure steam can be converted into electricity for production, thereby alleviating the tense situation of electricity consumption in enterprises and reducing the primary energy consumption of enterprises. It has the dual economic benefits of energy saving and cost reduction.

[0004] Gas steam boiler is a traditional steam generating device. Gas is directed to the combustion chamber and mixed with air for combustion, generating high temperature flue gas. Through the pipes and smoke pipes in the boiler, the heat energy is transferred to water. The water is heated in the boiler pipes and smoke pipes, and the temperature gradually increases and is converted into steam. When the water reaches the evaporation temperature, it forms steam and is discharged from the boiler.

[0005] Gas steam boilers use gas as energy, which is a non-renewable energy source. As gas resources become increasingly scarce and prices continue to rise, gas costs have become an important part of the production and operation costs of enterprises. In addition, the instability of gas supply has also had a great impact on the production of enterprises.

[0006] Although gas boilers use clean energy such as natural gas, there are still certain emissions, which do not meet the environmental protection requirements of zero emissions.

[0007] Boilers are special equipment, and the gases they burn are flammable and explosive, so they need to be regularly inspected to ensure production safety, which increases the safety management and operating costs of enterprises.

[0008] Traditional boilers take a long time to start up and output steam stably, and the steam output efficiency is low, resulting in long preheating time and long production cycle, thus reducing the production efficiency of the enterprise. During the production process, enterprises emit a large amount of low-temperature waste heat, which is dissipated into nature, wasting energy and polluting the environment. Recycling waste heat not only reduces the consumption of fossil combustion, but also reduces the production costs of enterprises.

[0009] Chinese application number CN201820093893.2 discloses an absorption heat pump device that recovers waste heat and compresses steam to drive it, which includes a waste heat recovery system, a steam compression system, and an absorption heat pump system. It recycles industrial waste heat, uses waste heat to provide low-pressure flash evaporation of working water, and the steam compressor recompresses the steam to drive the absorption heat pump device, achieving the dual effects of waste heat recovery and building air conditioning.

[0010] In the waste heat recovery device disclosed above, when water needs to be added to the pipeline during steam generation, heat is released by superheated steam to perform heat exchange on the added water, which affects the overall steam heating effect. When the added water needs to be directly converted into steam, the required energy usage is higher, which affects the overall energy conversion rate. Summary of the invention

[0011] The present invention aims to overcome the defects in the prior art and provide a multi-stage steam device utilizing waste heat recovery which has high energy conversion efficiency and can stably produce steam even under low heat source temperature conditions.

[0012] In order to achieve the above-mentioned invention object, the present invention adopts the following technical scheme: a multi-stage steam device utilizing waste heat recovery, comprising a heat source, a heat exchange system and a steam preparation system; the heat exchange system comprises a waste heat exchanger and a make-up water heat exchanger both connected to the heat source, and the waste heat exchanger and the make-up water heat exchanger are connected through a pipeline; the steam preparation system comprises a connected flash tank and a steam compressor, the flash tank is heat-exchangeably connected to the waste heat exchanger, and the flash tank is connected to the make-up water heat exchanger through a pipeline; the make-up water heat exchanger is provided with a make-up water tank connected through a pipeline, and the make-up water heat exchanger is connected to the steam compressor through a pipeline.

[0013] As a preferred embodiment of the present invention, the heat source is provided with a waste heat pipeline flowing through the waste heat exchanger and the make-up water heat exchanger in sequence, and the heat source is also provided with a shunt pipeline connected to the middle part of the waste heat pipeline, and the shunt pipeline is located between the waste heat exchanger and the make-up water heat exchanger.

[0014] As a preferred solution of the present invention, the water supply tank is provided with a water supply pipeline connected to the flash tank, and the water supply pipeline flows through the water supply heat exchanger.

[0015] As a preferred solution of the present invention, a branch pipeline connected to the steam compressor is provided on the water supply pipeline, and the branch pipeline is connected between the water supply heat exchanger and the flash tank.

[0016] As a preferred solution of the present invention, the water replenishment pipeline is provided with a water replenishment pump and a first solenoid valve for controlling the water replenishment amount of the flash tank, and the branch pipeline is provided with a booster pump and a second solenoid valve for controlling the water replenishment amount of the steam compressor.

[0017] As a preferred solution of the present invention, the flash tank is provided with a circulation pipeline for heat exchange through a waste heat exchanger, and the circulation pipeline is provided with a circulation pump for controlling the water flow in the flash tank for heat exchange.

[0018] As a preferred solution of the present invention, the flash tank is also connected to a vacuum pump for controlling the internal pressure of the flash tank.

[0019] As a preferred solution of the present invention, a gas outlet pipeline connected to a steam compressor is provided on the top of the flash tank.

[0020] As a preferred solution of the present invention, a drain valve is provided at the bottom of the flash tank.

[0021] As a preferred solution of the present invention, the water supply pipeline is provided with a first stop valve for controlling the input amount of the flash tank and a second stop valve for controlling the input amount of the steam compressor.

[0022] Compared with the prior art, the present invention has the following beneficial effects: by providing a waste heat exchanger and a water supply heat exchanger that are connected to each other, multi-stage heat exchange of the heat source is achieved, and effective utilization of the heat source is achieved; at the same time, the waste heat exchanger and the water supply heat exchanger are respectively provided corresponding to the circulation part of the flash tank and the water inlet part of the flash tank, so as to achieve multi-stage heat exchange of the water flow in the flash tank, increase the temperature of the water flow in the flash tank, and thus reduce the energy consumption required by the flash tank; During use, no other energy is consumed except electricity, the steam output is stable, and the cost is much lower than the steam production cost of gas boilers; There is zero emission during operation, which meets environmental protection requirements, has high gas outlet efficiency, and can be turned on and discharged immediately, which is beneficial to improving production efficiency. It has low requirements on the temperature of waste heat source, and the flash tank only needs to produce low-pressure low-order steam, which can eventually be obtained through a multi-stage mechanical compressor. High-pressure high-order steam. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a plan layout diagram of the present invention; Figure 2 It is a schematic diagram of the structure of the present invention; Figure 3 It is a front view of the present invention; Figure numerals: waste heat exchanger 1-1, make-up water heat exchanger 1-2, drain valve 2-1, first stop valve 2-2, second stop valve 2-3, make-up water pump 3-1, booster pump 3-2, circulation pump 3-3, first solenoid valve 4-1, second solenoid valve 4-2, make-up water tank 5, steam compressor 6, flash tank 7, vacuum pump 8, waste heat pipeline 9, diversion pipeline 9-1, circulation pipeline 10, make-up water pipeline 11, branch pipeline 11-1, outlet pipeline 12. DETAILED DESCRIPTION

[0024] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0025] like Figure 1-Figure 3 As shown, a multi-stage steam device utilizing waste heat recovery includes a heat source, a heat exchange system and a steam preparation system; the heat exchange system includes a waste heat heat exchanger 1-1 and a make-up water heat exchanger 1-2 both connected to the heat source, and the waste heat exchanger 1-1 and the make-up water heat exchanger 1-2 are connected through a pipeline; the steam preparation system includes a flash tank 7 and a steam compressor 6 connected to each other, the flash tank 7 is heat-exchange connected to the waste heat exchanger 1-1, and the flash tank 7 is connected to the make-up water heat exchanger 1-2 through a pipeline; the make-up water heat exchanger 1-2 is provided with a make-up water tank 5 connected through a pipeline, and the make-up water heat exchanger 1-2 is connected to the steam compressor 6 through a pipeline.

[0026] The heat source can be waste hot water with a certain amount of heat. The waste hot water flows through the waste heat exchanger 1-1 and the make-up water heat exchanger 1-2 in sequence. When the waste hot water flows through the waste heat exchanger 1-1, it realizes heat exchange with the water in the flash tank 7, and when the waste hot water flows through the make-up water heat exchanger 1-2, it realizes heat exchange with the water flowing out of the make-up water tank 5.

[0027] The flash tank 7 is used to receive the water after heat exchange and generate low-order steam, while the steam compressor 6 is used to receive the low-order steam and the water after heat exchange and generate high-order steam. The generated high-pressure steam can be used to provide better temperature and pressure, which is suitable for high-energy consumption industrial production processes.

[0028] The heat source is provided with a waste heat pipeline 9 which flows through the waste heat exchanger 1-1 and the make-up water heat exchanger 1-2 in sequence, and the heat source is also provided with a shunt pipeline 9-1 which is connected to the middle part of the waste heat pipeline 9, and the shunt pipeline 9-1 is located between the waste heat exchanger 1-1 and the make-up water heat exchanger 1-2.

[0029] The waste hot water is used as a heat source to provide heat for the waste heat exchanger 1-1 and the make-up water heat exchanger 1-2, and under the action of the waste heat exchanger 1-1 and the make-up water heat exchanger 1-2, the heat of the waste heat pipeline 9 is exchanged with the make-up water pipeline 11 and the circulation pipeline 10. The waste heat pipeline 9 first passes through the waste heat exchanger 1-1 and then passes through the make-up water heat exchanger 1-2, thereby realizing the primary heat exchange in the waste heat exchanger 1-1 and the secondary heat exchange in the make-up water heat exchanger 1-2.

[0030] The primary heat exchange effect of the waste heat pipeline 9 is better than the secondary heat exchange effect of the waste heat pipeline 9, thereby achieving a better heat exchange effect of the circulation pipeline 10 than the heat exchange effect of the water supply pipeline 11, and the water supply pipeline 11 and the circulation pipeline 10 are connected under the action of the flash tank 7, so that the water in the water supply pipeline 11 can be heat exchanged through the water supply heat exchanger 1-2 and then through the waste heat heat exchanger 1-1, thereby performing step-by-step heat exchange from low to high on the single water flow, thereby improving the heat exchange effect.

[0031] A three-way joint for connecting the bypass pipeline 9-1 is provided in the middle of the waste heat pipeline 9. The bypass pipeline 9-1 is also used to directly connect to the heat source. Under the action of the bypass pipeline 9-1, the temperature of the waste heat pipeline 9 flowing through the make-up water heat exchanger 1-2 is increased, and the waste hot water in the bypass pipeline 9-1 is used to mix with the waste hot water flowing through the waste heat exchanger 1-1.

[0032] Since the temperature of the waste hot water passing through the waste heat exchanger 1-1 is reduced due to the reheat exchange effect, the waste hot water in the shunt pipe 9-1 increases the water flow temperature in the waste heat pipe 9, thereby ensuring that the make-up water heat exchanger 1-2 also has a good heat exchange effect during the heat exchange process. At the same time, since the water flowing through the make-up water heat exchanger 1-2 is mixed with the waste hot water after the initial heat exchange through the shunt pipe 9-1, the temperature of the mixed waste hot water is inevitably lower than the temperature of the waste hot water during the initial heat exchange, satisfying the above-mentioned primary heat exchange effect in the waste heat exchanger 1-1 is better than the secondary heat exchange effect in the make-up water heat exchanger 1-2.

[0033] A water supply pipe 11 connected to the flash tank 7 is provided on the water supply tank 5, and the water supply pipe 11 flows through the water supply heat exchanger 1-2. Under the action of the water supply pipe 11, the water in the flash tank 7 is replenished to meet the demand of the flash tank to continuously generate low-order steam. At the same time, under the action of the water supply heat exchanger 1-2, the water flowing out of the water supply tank 5 is heated by heat exchange, thereby increasing the temperature of the water flow entering the flash tank 7, thereby reducing the energy consumption required for the flash tank 7 to generate low-order steam.

[0034] The water supply pipeline 11 is provided with a branch pipeline 11-1 connected to the steam compressor 6. The branch pipeline 11-1 is connected between the water supply heat exchanger 1-2 and the flash tank 7. The water supply pipeline 11 can simultaneously realize the water supply operation of the flash tank 7 and the steam compressor 6, and the water flow for replenishing the steam compressor 6 also passes through the water supply heat exchanger 1-2 for heat exchange.

[0035] The flash tank 7 is also connected to a vacuum pump 8 for controlling the internal pressure of the flash tank 7 .

[0036] During use, the pressure of the flash tank 7 is pumped down by the vacuum pump 8. When the system is running, the circulating water passes through the waste heat exchanger 1-1 in the circulating pipeline 10, absorbs heat from the waste hot water to increase the temperature, and returns to the flash tank 7 to flash out low-temperature and low-pressure saturated steam. The replenishment water of the flash tank 7 passes through the replenishment water heat exchanger 1-2 in the replenishment water pipeline 11, further absorbs the heat in the waste hot water, and a part of it enters the flash tank 7 through the replenishment water pipeline 11, and the other part enters the cooling water system of the steam compressor 6 through the branch pipeline 11-1 to protect the unit from overheating. At the same time, the heat generated by the steam compressor 6 when working evaporates the replenishment water, which can increase the steam production. The steam compressor 6 is driven by electrical energy and continuously provides steam for the production system.

[0037] The water supply pipeline 11 is provided with a water supply pump 3-1 and a first solenoid valve 4-1 for controlling the water supply amount of the flash tank 7, and the branch pipeline 11-1 is provided with a booster pump 3-2 and a second solenoid valve 4-2 for controlling the water supply amount of the steam compressor 6.

[0038] The first solenoid valve 4-1 and the water replenishment pump 3-1 are used to control the amount of water replenished by the water replenishment tank 5 to the flash tank 7. Under the action of the first solenoid valve 4-1 and the water replenishment pump 3-1, the flash tank 7 is replenished with water of the same mass as the drainage steam of the flash tank 7 during the water replenishment process, thereby ensuring that the flash tank 7 is always in a relatively constant pressure environment.

[0039] The booster pump 3-2 and the second solenoid valve 4-2 are used to control the water replenishment amount of the steam compressor 6. Under the action of the booster pump 3-2 and the second solenoid valve 4-2, the outlet steam superheat of the steam compressor 6 is adjusted to ensure that the steam compressor 6 produces superheated / saturated steam.

[0040] The flash tank 7 is provided with a circulation pipeline 10 for heat exchange through the waste heat exchanger 1 - 1 , and the circulation pipeline 10 is provided with a circulation pump 3 - 3 for controlling the water flow in the flash tank 7 for heat exchange.

[0041] The circulation pump 3 - 3 is used to drive the flow of water in the circulation pipeline 10 . Under the flow of water in the circulation pipeline 10 , the circulation pipeline 10 cooperates with the waste heat exchanger 1 - 1 to achieve heat exchange and heating of the water in the flash tank 7 .

[0042] An outlet pipe 12 connected to the steam compressor 6 is provided at the top of the flash tank 7. Under the action of the flash tank 7, low-order steam is formed in the flash tank 7 and discharged upward under the action of the low-order steam itself. The low-order steam flows into the steam compressor 6 through the outlet pipe 12. A drain valve 2-1 is provided at the bottom of the flash tank 7.

[0043] The water supply pipeline 11 is provided with a first stop valve 2 - 2 for controlling the input amount of the flash tank 7 and a second stop valve 2 - 3 for controlling the input amount of the steam compressor 6 .

[0044] In actual use, the waste heat pipe 9 flows through the waste heat exchanger 1-1 and the make-up water heat exchanger 1-2 in sequence, so that the waste heat pipe 9 performs multi-stage heat exchange on the waste heat exchanger 1-1 and the make-up water heat exchanger 1-2, and the water in the flash tank 7 is heat exchanged during the heat exchange process of the waste heat exchanger 1-1. The make-up water heat exchanger 1-2 is used to heat the water supply of the make-up water tank 5, thereby performing multi-stage heat exchange on the water inlet of the flash tank 7 and the internal circulation of the flash tank 7, ensuring the effective use of the waste hot water.

[0045] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention; therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

[0046] Although the following terms are used more frequently in this paper: waste heat exchanger 1-1, water supply heat exchanger 1-2, drain valve 2-1, first stop valve 2-2, second stop valve 2-3, water supply pump 3-1, pressure pump 3-2, circulation pump 3-3, first solenoid valve 4-1, second solenoid valve 4-2, water supply tank 5, steam compressor 6, flash tank 7, vacuum pump 8, waste heat pipeline 9, diversion pipeline 9-1, circulation pipeline 10, water supply pipeline 11, branch pipeline 11-1, air outlet pipeline 12, etc., the possibility of using other terms is not excluded. These terms are used only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional restrictions is contrary to the spirit of the present invention.

Claims

1. A multi-stage steam device utilizing waste heat recovery, comprising a heat source, a heat exchange system and a steam preparation system; characterized in that: The heat exchange system comprises a waste heat exchanger (1-1) and a water replenishment heat exchanger (1-2) both of which are connected to a heat source, and the waste heat exchanger (1-1) and the water replenishment heat exchanger (1-2) are connected via a pipeline; the steam preparation system comprises a flash tank (7) and a steam compressor (6) which are connected, the flash tank (7) and the waste heat exchanger (1-1) are heat exchange-connected, and the flash tank (7) and the water replenishment heat exchanger (1-2) are connected via a pipeline; the water replenishment heat exchanger (1-2) is provided with a water replenishment tank (5) which is connected via a pipeline, and the water replenishment heat exchanger (1-2) and the steam compressor (6) are connected via a pipeline.

2. A multi-stage steam device utilizing waste heat recovery according to claim 1, characterized in that: The heat source is provided with a waste heat pipeline (9) which flows through the waste heat exchanger (1-1) and the water-making heat exchanger (1-2) in sequence, and the heat source is also provided with a shunt pipeline (9-1) which is connected to the middle part of the waste heat pipeline (9), and the shunt pipeline (9-1) is located between the waste heat exchanger (1-1) and the water-making heat exchanger (1-2).

3. The multi-stage steam device utilizing waste heat recovery according to claim 1, characterized in that: The water supply tank (5) is provided with a water supply pipeline (11) connected to the flash tank (7), and the water supply pipeline (11) flows through the water supply heat exchanger (1-2).

4. A multi-stage steam device utilizing waste heat recovery according to claim 3, characterized in that: The water supply pipeline (11) is provided with a branch pipeline (11-1) connected to the steam compressor (6), and the branch pipeline (11-1) is connected between the water supply heat exchanger (1-2) and the flash tank (7).

5. A multi-stage steam device utilizing waste heat recovery according to claim 4, characterized in that: The water replenishment pipeline (11) is provided with a water replenishment pump (3-1) and a first solenoid valve (4-1) for controlling the water replenishment amount of the flash tank (7), and the branch pipeline (11-1) is provided with a booster pump (3-2) and a second solenoid valve (4-2) for controlling the water replenishment amount of the steam compressor (6).

6. The multi-stage steam device utilizing waste heat recovery according to claim 1, characterized in that: The flash tank (7) is provided with a circulation pipeline (10) for performing heat exchange through a waste heat exchanger (1-1), and the circulation pipeline (10) is provided with a circulation pump (3-3) for controlling the water flow in the flash tank (7) for performing heat exchange.

7. A multi-stage steam device utilizing waste heat recovery according to claim 6, characterized in that: The flash tank (7) is also connected to a vacuum pump (8) for controlling the internal pressure of the flash tank (7).

8. The multi-stage steam device utilizing waste heat recovery according to claim 6, characterized in that: The top of the flash tank (7) is provided with a gas outlet pipeline (12) which is connected to the steam compressor (6).

9. The multi-stage steam device utilizing waste heat recovery according to claim 6, characterized in that: A sewage valve (2-1) is provided at the bottom of the flash tank (7).

10. The multi-stage steam device utilizing waste heat recovery according to claim 3, characterized in that: The water supply pipeline (11) is provided with a first stop valve (2-2) for controlling the input amount of the flash tank (7) and a second stop valve (2-3) for controlling the input amount of the steam compressor (6).

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