Flash steam heat recycling system and method

Abstract

The invention discloses a flash steam heat recycling system and method, and relates to the technical field of flash steam recycling. The flash steam heat recycling system comprises a condensate water collecting tank, a flash strengthening device, a gas-liquid separator, a first heating device, a second heating device and a steam distributing device, the flash strengthening device is used for improving the flash effect in the condensate water collecting tank to increase the output of flash steam, the first heating device is used for heating the flash steam, and the second heating device is used for heating the flash steam to increase the output of the flash steam. Primary heating steam is formed; and the second heating device is used for heating the primary heating steam to form secondary heating steam. According to the flash steam heat recycling system and method, flash steam generated when condensate water is discharged can be effectively recycled, the flash steam is converted into useful energy, and the problems that heat is wasted and the environment is affected due to direct discharging of the flash steam are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of flash steam recovery and utilization, and in particular to a flash steam heat recovery and utilization system and method. Background Art

[0002] In the industrial production process, high-pressure steam is often needed as a heat source to heat materials or systems. During the heating process, high-pressure steam transfers heat to the material or system to increase its temperature. As the heat is released, the temperature and pressure of the high-pressure steam gradually decrease. When the temperature of the high-pressure steam drops below its saturation temperature, the high-pressure steam begins to condense into liquid water with a certain temperature, namely condensed water.

[0003] When the condensed water produced by high-pressure steam is discharged into an environment of atmospheric pressure, due to the sudden decrease in pressure, part of the condensed water will absorb heat and evaporate again to form flash steam. These flash steams are usually regarded as waste in the production process and discharged directly into the atmosphere. Flash steam has a high heat content. If it is not recycled, it will cause a large amount of heat energy loss. In addition, although the main component of flash steam is water vapor, in some cases, if water vapor condenses and releases latent heat, it may indirectly affect climate change. Therefore, in order to reduce heat energy loss and reduce the impact on the environment, it is urgent to take measures to recycle flash steam. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to propose a flash steam heat recovery and utilization system, which can effectively recover the flash steam generated when condensed water is discharged and convert the flash steam into useful energy, thereby solving the problem of heat waste and environmental impact caused by direct discharge of flash steam.

[0005] Another object of the present invention is to propose a flash steam heat recovery method, which can effectively recover the flash steam generated when condensed water is discharged and convert the flash steam into useful energy, thereby solving the problem of heat waste and environmental impact caused by direct discharge of flash steam.

[0006] In order to solve the above technical problems, the present invention provides a flash steam heat recovery system, including a condensate collection tank, a flash enhancement device, a gas-liquid separator, a first heating device, a second heating device and a steam separation device;

[0007] The condensed water collection tank is provided with a condensed water input end, a flash steam output end, a condensed water output end, a circulating water recovery end and a separation liquid recovery end. The condensed water input end is connected to an external condensed water mother pipe, the condensed water output end is connected to the input end of the flash evaporation enhancement device, the output end of the flash evaporation enhancement device is connected to the circulating water recovery end, and the flash evaporation enhancement device is used to increase the flash evaporation effect in the condensed water collection tank; the flash steam output end is connected to the input end of the gas-liquid separator, and the separation liquid recovery end is connected to the liquid output end of the gas-liquid separator;

[0008] The steam output end of the gas-liquid separator is connected to the input end of the first heating device, the output end of the first heating device is connected to the input end of the second heating device, the output end of the second heating device is connected to the input end of the steam separation device, the output end of the steam separation device is connected to the main pipe of the external steam-using equipment, the first heating device is used to heat the flash steam to form primary heating steam; the second heating device is used to heat the primary heating steam to form secondary heating steam.

[0009] Preferably, the flash evaporation enhancement device includes a circulation pump, a first circulation pipe and a second circulation pipe, the condensed water output end is connected to the input end of the first circulation pipe, the output end of the first circulation pipe is connected to the suction end of the circulation pump, the discharge end of the circulation pump is connected to the input end of the second circulation pipe, and the output end of the second circulation pipe is connected to the circulating water recovery end.

[0010] Preferably, the flash steam heat recovery system further comprises a condensate water tank, a first input end of the condensate water tank is connected to the condensate main pipe, and a second input end of the condensate water tank is connected to the discharge end of the circulation pump.

[0011] Preferably, the second heating device is a steam ejector, which is provided with two input ends, namely a low-pressure steam input end and a high-pressure steam input end. The low-pressure steam input end is connected to the output end of the first heating device, the high-pressure steam input end is connected to the external first high-pressure raw steam pipeline, and the output end of the steam ejector is connected to the input end of the steam separation device.

[0012] Preferably, the steam separation device is provided with two input ends, namely a secondary heating steam input end and a spare input end. The secondary heating steam input end of the steam separation device is connected to the output end of the second heating device, and the spare input end of the steam separation device is connected to the external second high-pressure raw steam pipeline.

[0013] Preferably, the condensate main pipe and the condensate input end are connected through a first pipeline, and a first regulating valve is provided on the first pipeline;

[0014] The condensate main pipe and the first input end of the condensate tank are connected through a second pipe, and a second regulating valve is provided on the second pipe;

[0015] The discharge end of the circulation pump and the second input end of the condensate water tank are connected through a third pipeline, and a third regulating valve is provided on the third pipeline;

[0016] The output end of the second heating device and the secondary heating steam input end of the steam separation device are connected through a fourth pipeline, and a fourth regulating valve is provided on the fourth pipeline;

[0017] The second circulation pipeline is provided with a fifth regulating valve, the first high-pressure raw steam pipeline is provided with a sixth regulating valve, and the second high-pressure raw steam pipeline is provided with a seventh regulating valve.

[0018] Preferably, the first temperature increasing device is a steam compressor.

[0019] Preferably, the condensed water output end, the condensed water input end, the circulating water recovery end, the separated liquid recovery end and the flash steam output end are sequentially arranged in the condensed water collection tank from bottom to top;

[0020] The height difference between the condensate output end and the circulating water recovery end is h1, the total height of the condensate collection tank is h2, and h1 and h2 satisfy the following formula: h1=(0.5-0.9)h2.

[0021] Accordingly, the present invention also provides a flash steam heat recovery method, which uses the above-mentioned flash steam heat recovery system and includes the following steps:

[0022] (1) Condensed water is passed into a condensed water collection tank to generate flash steam in the condensed water collection tank; the condensed water in the condensed water collection tank is circulated by a circulating pump; the temperature of the flash steam is 80 to 100° C.;

[0023] (2) heating the flash steam generated in the condensate collection tank for the first time to obtain primary heated steam, wherein the temperature of the primary heated steam is 100° C. to 140° C.;

[0024] (3) heating the primary heated steam again to obtain secondary heated steam; the temperature of the secondary heated steam is 120° C. to 200° C.;

[0025] (4) The secondary heated steam is input into a steam separation device, and distributed to steam-consuming equipment through the steam separation device.

[0026] Preferably, in step (2), a steam compressor is used to heat the flash steam for the first time to obtain primary heated steam;

[0027] In step (3), the primary heated steam is heated again by introducing raw steam to obtain secondary heated steam; the temperature of the raw steam is 200°C to 300°C.

[0028] The implementation of the present invention has the following beneficial effects:

[0029] 1. The flash steam heat recovery system of this technical solution can effectively recover the flash steam generated when the condensed water is discharged, and heat and pressure the low-pressure flash steam twice to meet the steam requirements of steam users, achieving the technical effect of recycling flash steam and filling the technical gap of heat recovery of flash steam. The flash steam heat recovery system of this technical solution not only helps to reduce energy waste and improve energy utilization efficiency, but also reduces the impact on the environment.

[0030] 2. This technical solution collects the condensed water into a condensed water collection tank, and a flash evaporation enhancement device is connected to the outside of the condensed water collection tank, which is beneficial to the cyclic evaporation of the condensed water, increases the flash evaporation effect of the condensed water in the condensed water collection tank, and thereby increases the amount of flash evaporation steam.

[0031] 3. The first heating of this technical solution is carried out by a steam compressor, which compresses the flash steam to increase the pressure and temperature of the flash steam; the second heating is to further increase the pressure and temperature of the flash steam by introducing high-temperature raw steam for heat exchange. The two-step heating method of this technical solution can not only obtain medium-pressure steam that meets user needs, but also effectively save costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a schematic structural diagram of a flash steam heat recovery system according to an embodiment of the present invention;

[0033] Figure 2 yes Figure 1 A schematic diagram of the structure of a condensate collection tank in a flash steam heat recovery system in the illustrated embodiment;

[0034] In the figure: condensate collection tank 1, flash enhancement device 2, gas-liquid separator 3, first heating device 4, second heating device 5, steam separation device 6, condensate tank 7, condensate mother pipe 8, condensate input end 11, flash steam output end 12, condensate output end 13, circulating water recovery end 14, separated liquid recovery end 15, circulating pump 21, first circulating pipeline 22, second circulating pipeline 23, first high-pressure raw steam pipeline 91, second high-pressure raw steam pipeline 92, first pipeline 93, second pipeline 94, third pipeline 95, fourth pipeline 96, steam-using equipment mother pipe 97. DETAILED DESCRIPTION

[0035] To make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0036] In the description of the present invention, it is necessary to understand that the orientations or positional relationships indicated by terms such as “upper”, “lower”, “left”, “right”, “top” and “bottom” are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0037] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connection" and "communication" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] like Figure 1 to Figure 2 As shown, a flash steam heat recovery system comprises a condensate collection tank 1, a flash enhancement device 2, a gas-liquid separator 3, a first temperature increasing device 4, a second temperature increasing device 5 and a steam separation device 6;

[0039] The condensed water collection tank 1 is provided with a condensed water input end 11, a flash steam output end 12, a condensed water output end 13, a circulating water recovery end 14 and a separation liquid recovery end 15. The condensed water input end 11 is connected to the external condensed water mother pipe 8, the condensed water output end 13 is connected to the input end of the flash evaporation enhancement device 2, the output end of the flash evaporation enhancement device 2 is connected to the circulating water recovery end 14, and the flash evaporation enhancement device 2 is used to increase the flash evaporation effect in the condensed water collection tank 1, thereby increasing the amount of flash steam generated; the flash steam output end 12 is connected to the input end of the gas-liquid separator 3, and the separation liquid recovery end 15 is connected to the liquid output end of the gas-liquid separator 3;

[0040] The steam output end of the gas-liquid separator 3 is connected to the input end of the first heating device 4, the output end of the first heating device 4 is connected to the input end of the second heating device 5, the output end of the second heating device 5 is connected to the input end of the steam separation device 6, the output end of the steam separation device 6 is connected to the external steam-using equipment main pipe 97, the first heating device 4 is used to heat the flash steam to form primary heating steam; the second heating device 5 is used to heat the primary heating steam to form secondary heating steam.

[0041] Specifically, the flash steam heat recovery system of the present technical solution includes a condensate collection tank 1, a flash enhancement device 2, a gas-liquid separator 3, a first temperature rising device 4, a second temperature rising device 5 and a steam separation device 6. The working process of the flash steam heat recovery system is as follows: first, the condensate generated by the high-pressure raw steam user is discharged to the condensate mother pipe 8, and then discharged into the condensate collection tank 1 through the condensate mother pipe 8. Due to the sudden drop in pressure, part of the condensate evaporates secondary in the condensate collection tank 1 to form flash steam; when the heat recovery system is normally started, the condensate in the condensate collection tank enters the flash enhancement device 2 through the condensate output terminal 13, and the flash enhancement device 2 increases the flash effect of the condensate in the condensate collection tank 1, so that more flash steam is generated; the generated flash steam enters the gas-liquid separator 3, and passes through the second temperature rising device 5 and the second temperature rising device 6. The gas-liquid separator 3 separates the liquid droplets mixed in the flash steam, ensuring that the mixed liquid droplets in the flash steam return to the condensate collection tank 1, and only the flash steam enters the first heating device 4; the flash steam is heated and pressurized once by the first heating device 4 to obtain primary heated steam, and the primary heated steam enters the second heating device 5 for secondary heating and pressure increase; the secondary heated steam that has achieved secondary heating and pressure increase enters the steam separation device 6, and the steam separation device 6 is connected to the external steam-using equipment through the steam-using equipment main pipe, and the secondary heated steam (i.e., medium-pressure steam) is transported to the steam user through the steam-using equipment.

[0042] It is worth noting that the present technical solution collects condensed water into the condensed water collection tank 1, and the condensed water collection tank 1 is connected to the flash evaporation enhancement device 2. The flash evaporation enhancement device 2 is beneficial to the cyclic evaporation of condensed water, increases the flash evaporation effect of condensed water in the condensed water collection tank 1, and thus increases the amount of flash steam. The flash steam output end 12 of the condensed water collection tank 1 is connected to the gas-liquid separator 3. The flash steam separated by the gas-liquid separator 3 enters the first heating device 4 for heating and pressure increase to the set pressure, and then obtains the primary heating steam; the primary heating steam enters the second heating device 5 for the second heating and pressure increase, and forms the secondary heating steam. The secondary heating steam is medium-pressure steam, which meets the steam requirements of steam users. The secondary heating steam directly enters the steam separation device 6, and the steam separation device 6 is connected to each steam user through the steam-using equipment to provide steam for each steam user. The flash steam heat recovery system of the present technical solution can effectively recover the flash steam generated when condensed water is discharged, and heat and pressure the low-pressure flash steam twice to obtain steam that meets the steam requirements of steam users, thereby achieving the technical effect of recycling and utilizing flash steam and filling the technical gap in heat recovery of flash steam.

[0043] Further explanation, the flash steam heat recovery system of the technical solution is mainly used to recover and utilize the low-pressure flash steam (temperature is usually 80-100°C) generated in the industrial production process. These low-pressure flash steam are usually regarded as waste in the production process. Through the flash steam heat recovery system of the technical solution, the low-pressure flash steam can be converted into useful energy, such as thermal energy or mechanical energy, and the heat energy in the flash steam can be effectively recovered to avoid a large amount of waste caused by direct heat discharge, thereby realizing the reuse of energy. The flash steam heat recovery system of the technical solution not only helps to reduce energy waste, improve energy utilization efficiency, meet the requirements of sustainable development, but also reduce the impact on the environment. More importantly, the flash steam heat recovery system of the technical solution can pressurize the low-pressure flash steam to above 0.2MPa, which can be directly used by steam users, and the flash steam heat recovery system of the technical solution is simple to operate, safe and reliable, and has a high degree of automation.

[0044] Preferably, a liquid level detector, a temperature detector and a pressure detector are provided inside the condensed water collection tank 1 , which are used to detect the liquid level, temperature and pressure inside the condensed water collection tank 1 , respectively.

[0045] To further explain, the flash evaporation enhancement device 2 includes a circulation pump 21, a first circulation pipe 22 and a second circulation pipe 23, the condensed water output end 13 is connected to the input end of the first circulation pipe 22, the output end of the first circulation pipe 22 is connected to the suction end of the circulation pump 21, the discharge end of the circulation pump 21 is connected to the input end of the second circulation pipe 23, and the output end of the second circulation pipe 23 is connected to the circulating water recovery end 14.

[0046] It is worth noting that, in the present technical solution, the condensed water in the condensed water collection tank 1 is continuously circulated through the first circulation pipe 22, the circulation pump 21 and the second circulation pipe 23. Based on the fact that water is a poor conductor of heat, the circulating energy of the condensed water can ensure that the water temperature in the condensed water collection tank 1 is consistent, so that the condensed water can be fully flashed, thereby increasing the flashing effect of the condensed water in the condensed water collection tank 1, and thus being able to more effectively recover the heat energy in the flash steam, realize economical and environmentally friendly energy utilization, and further reduce heat waste.

[0047] Further explanation, the first temperature increasing device 4 is a steam compressor. By compressing the flash steam with a steam compressor, the pressure and temperature of the flash steam can be increased, so that the temperature of the obtained primary temperature increasing steam reaches 100-140°C, and the use of a steam compressor to increase the temperature and pressure can effectively reduce costs.

[0048] More preferably, the steam compressor is a Roots steam compressor.

[0049] Further explanation, the second heating device 5 is a steam ejector, and the steam ejector is provided with two input ends, namely a low-pressure steam input end and a high-pressure steam input end. The low-pressure steam input end is connected to the output end of the first heating device 4, the high-pressure steam input end is connected to the external first high-pressure raw steam pipeline 91, and the output end of the steam ejector is connected to the input end of the steam separation device 6.

[0050] It is worth noting that the primary heated steam (temperature of 100-140°C) processed by the first heating device 4 of the technical solution enters the steam ejector through the low-pressure steam input end for a second heating and pressure increase. Since the high-pressure steam input end of the steam ejector is connected to the external first high-pressure raw steam pipeline 91, high-temperature raw steam (200°C-300°C) can be input into the steam ejector, and a high-speed airflow is generated through the Rafale nozzle of the steam ejector, which can continuously draw the primary heated steam from the first heating device 4, so that the primary heated steam and the high-temperature raw steam are mixed to form medium-pressure mixed steam, i.e., secondary heated steam (temperature of 120-200°C).

[0051] It is worth noting that the first heating of the technical solution is carried out by a steam compressor, and the flash steam is compressed by the steam compressor to increase the pressure and temperature of the flash steam; the second heating is to further increase the pressure and temperature of the flash steam by introducing high-temperature raw steam for heat exchange. The two-step heating method of the technical solution can not only obtain medium-pressure steam that meets user needs, but also effectively save costs. Although a large amount of high-temperature raw steam can be directly introduced to make the temperature of the flash steam reach the required value, this method will consume a large amount of high-temperature raw steam, which will result in high costs. Therefore, the technical solution adopts a two-step heating method. The first step is to heat up by a steam compressor. However, due to the reasons of the steam compressor itself, the temperature that can be raised by using a steam compressor to heat up is limited. Since the temperature of the flash steam is usually 80-100°C, when the target steam temperature is too high (such as 160°C), it is difficult to obtain steam with too high a temperature by heating up with a steam compressor. Therefore, the technical solution further increases the temperature of the steam by introducing a certain amount of high-temperature raw steam to make the steam temperature reach the target steam temperature. Compared with the method of directly introducing a large amount of high-temperature raw steam to make the temperature of the flash steam reach the target temperature at one time, the method of this scheme can effectively reduce costs.

[0052] To further explain, the flash steam heat recovery system also includes a condensate water tank 7, a first input end of the condensate water tank 7 is connected to the condensate main pipe 8, and a second input end of the condensate water tank 7 is connected to the discharge end of the circulation pump 21.

[0053] When the flash steam heat recovery system of the present technical solution is not started or has a fault, the condensed water discharged from the condensed water main pipe 8 is directly discharged into the condensed water tank 7. In addition, when there is too much condensed water in the condensed water collection tank 1, the excess condensed water in the condensed water collection tank 1 can also be discharged into the condensed water tank 7 through the circulating pump 21.

[0054] For further explanation, the steam separation device 6 is provided with two input ends, namely a secondary heating steam input end and a spare input end. The secondary heating steam input end of the steam separation device 6 is connected to the output end of the second heating device 5, and the spare input end of the steam separation device 6 is connected to the external second high-pressure raw steam pipeline 92.

[0055] In order to prevent the situation that the amount of flash steam is very small before the system starts, and the amount of steam in the steam separation device 6 is insufficient, the technical solution is provided with a spare input end in the steam separation device 6, and the input end is connected to the external second high-pressure raw steam pipeline 92, and high-pressure raw steam can be input into the steam separation device 6 through the second high-pressure raw steam pipeline 92, as a startup steam source and a spare steam source during normal operation, to ensure that the flash steam heat recovery and utilization system of the technical solution can always provide a stable steam source, and to ensure that there is always enough pressure steam for steam users from the steam separation device 6 to the main pipe 97 of each steam-using equipment. Specifically, when the pressure in the steam separation device 6 is insufficient, the spare input end of the steam separation device 6 is opened, and high-pressure raw steam is introduced into the steam separation device 6 through the spare input end, so that the steam separation device 6 can always be guaranteed to have enough pressure steam.

[0056] Preferably, the steam separation device 6 is a steam separation cylinder.

[0057] Further explanation, the condensed water main pipe 8 and the condensed water input end 11 are connected through a first pipe 93, and a first regulating valve is provided on the first pipe 93; the first regulating valve can control the flow of the first pipe 93, thereby controlling whether to pass condensed water into the condensed water collection tank 1, and controlling the amount of condensed water passed into the condensed water collection tank 1;

[0058] The condensate main pipe 8 is connected to the first input end of the condensate tank 7 via a second pipe 94, and a second regulating valve is provided on the second pipe 94;

[0059] The discharge end of the circulation pump 21 and the second input end of the condensed water tank 7 are connected through a third pipe 95, and a third regulating valve is provided on the third pipe 95;

[0060] The output end of the second heating device 5 and the secondary heating steam input end of the steam separation device 6 are connected through a fourth pipeline 96, and a fourth regulating valve is provided on the fourth pipeline 96;

[0061] The second circulation pipeline 23 is provided with a fifth regulating valve, the first high-pressure raw steam pipeline 91 is provided with a sixth regulating valve, and the second high-pressure raw steam pipeline 92 is provided with a seventh regulating valve.

[0062] Preferably, the steam separation device 6 is provided with a pressure detector for detecting the pressure of the steam inside the steam separation device 6 .

[0063] Preferably, a pressure detector and a temperature detector are provided on the fourth pipeline 96 for detecting the pressure and temperature of the steam in the fourth pipeline 96 .

[0064] Preferably, a pressure detector is also provided on the connecting pipe between the output end of the first heating device 4 and the input end of the second heating device 5, for detecting the pressure of the primary heating steam in the connecting pipe.

[0065] It is worth noting that the flash steam heat recovery system of the present technical solution starts when the liquid level and temperature of the condensed water in the condensed water collection tank 1 reach the set value. When the liquid level of the condensed water in the condensed water collection tank 1 is too high, the second regulating valve is opened to discharge the excess condensed water in the condensed water main pipe 8 into the condensed water tank 7. The opening of the seventh regulating valve on the second high-pressure raw steam pipeline 92 is controlled by the pressure of the steam separation device 6. When the pressure in the steam separation device 6 decreases, the opening of the seventh regulating valve increases, so that more high-pressure steam enters the interior of the steam separation device 6.

[0066] Further explanation, the condensed water output end 13, the condensed water input end 11, the circulating water recovery end 14, the separation liquid recovery end 15 and the flash steam output end 12 are sequentially arranged in the condensed water collection tank 1 from bottom to top; Figure 2 As shown, in an optional embodiment, the condensate input end 11 is located at the lower part of the condensate collection tank 1, the flash steam output end 12 is located at the top of the condensate collection tank 1, the condensate output end 13 is located at the bottom of the condensate collection tank 1, the circulating water recovery end 14 is located in the middle of the condensate collection tank 1 in the vertical direction, and the separation liquid recovery end 15 is located at the upper part of the condensate collection tank 1.

[0067] Further explanation, the height difference between the condensed water output end 13 and the circulating water recovery end 14 is h1, the total height of the condensed water collection tank 1 is h2, and the h1 and h2 satisfy the following formula: h1 = (0.5-0.9) h2. When the height difference between the condensed water output end 13 and the circulating water recovery end 14 satisfies the above formula, the flash evaporation effect of the condensed water in the condensed water collection tank 1 can be further increased, thereby enabling the condensed water to fully flash.

[0068] A flash steam heat recovery method, using the above-mentioned flash steam heat recovery system, comprises the following steps:

[0069] (1) Condensed water is introduced into the condensed water collection tank 1 to generate flash steam in the condensed water collection tank 1; the condensed water in the condensed water collection tank 1 is circulated by a circulating pump 21; the temperature of the flash steam is 80-100° C.;

[0070] (2) heating the flash steam generated in the condensate collection tank 1 for the first time to obtain primary heated steam, wherein the temperature of the primary heated steam is 100° C. to 140° C.;

[0071] (3) heating the primary heated steam again to obtain secondary heated steam; the temperature of the secondary heated steam is 120° C. to 200° C.;

[0072] (4) The secondary heated steam is input to the steam separation device 6 and distributed to the steam-consuming equipment through the steam separation device 6.

[0073] The flash steam heat recovery and utilization method of the technical solution can effectively recover the thermal energy of the flash steam after the condensate is discharged. The technical solution recovers the flash steam with a slight negative pressure and reuses it after heating and pressurizing. The temperature of the secondary heated steam formed after the secondary heating and pressurizing of the technical solution is 160℃~200℃, which is medium-pressure steam and can meet the needs of steam users for medium-pressure steam.

[0074] Specifically, the temperature of the primary heating steam is 100°C to 140°C, and the pressure of the primary heating steam is the saturated steam pressure at this temperature; the temperature of the secondary heating steam is 120°C to 200°C, and the pressure of the secondary heating steam is the saturated steam pressure at this temperature.

[0075] To further illustrate, in step (2), a steam compressor is used to heat the flash steam for the first time to obtain primary heated steam;

[0076] In step (3), the primary heated steam is heated again by introducing raw steam to obtain secondary heated steam; the temperature of the raw steam is 200°C to 300°C.

[0077] Preferably, the flow rate of the circulation pump 21 is 40-55 t / h, and the flow rate of the condensed water circulating in the condensed water collection tank 1 is ≥1 m / s.

[0078] It is worth noting that the present technical solution can further increase the flash evaporation effect of the condensed water in the condensed water collection tank 1 by controlling the flow rate of the circulating pump 21 to 40-55 t / h and controlling the circulation velocity of the condensed water in the condensed water collection tank 1 to be ≥1 m / s, thereby generating more flash steam in the condensed water collection tank 1 and more effectively recovering the thermal energy of the flash steam.

[0079] The technical principle of the present invention is described above in conjunction with specific embodiments. These descriptions are only for explaining the principle of the present invention and cannot be interpreted as limiting the scope of protection of the present invention in any way. Based on the explanations herein, those skilled in the art can associate other specific implementations of the present invention without paying creative labor, and these methods will fall within the scope of protection of the present invention.

Claims

1. A flash steam heat recovery system, characterized in that: It includes a condensate collection tank, a flash evaporation enhancement device, a gas-liquid separator, a first heating device, a second heating device and a steam separation device; The condensed water collection tank is provided with a condensed water input end, a flash steam output end, a condensed water output end, a circulating water recovery end and a separation liquid recovery end. The condensed water input end is connected to an external condensed water mother pipe, the condensed water output end is connected to the input end of the flash evaporation enhancement device, the output end of the flash evaporation enhancement device is connected to the circulating water recovery end, and the flash evaporation enhancement device is used to increase the flash evaporation effect in the condensed water collection tank; the flash steam output end is connected to the input end of the gas-liquid separator, and the separation liquid recovery end is connected to the liquid output end of the gas-liquid separator; The steam output end of the gas-liquid separator is connected to the input end of the first heating device, the output end of the first heating device is connected to the input end of the second heating device, the output end of the second heating device is connected to the input end of the steam separation device, the output end of the steam separation device is connected to the main pipe of the external steam-using equipment, the first heating device is used to heat the flash steam to form primary heating steam; the second heating device is used to heat the primary heating steam to form secondary heating steam.

2. The flash steam heat recovery system according to claim 1, characterized in that: The flash evaporation enhancement device includes a circulation pump, a first circulation pipe and a second circulation pipe. The condensed water output end is connected to the input end of the first circulation pipe, the output end of the first circulation pipe is connected to the suction end of the circulation pump, the discharge end of the circulation pump is connected to the input end of the second circulation pipe, the output end of the second circulation pipe is connected to the circulation water recovery end, and the circulation pump is used to circulate the condensed water in the condensed water collection tank.

3. The flash steam heat recovery system according to claim 1, characterized in that: The first temperature increasing device is a steam compressor.

4. The flash steam heat recovery system according to claim 3, characterized in that: The second heating device is a steam ejector, which is provided with two input ends, namely a low-pressure steam input end and a high-pressure steam input end. The low-pressure steam input end is connected to the output end of the first heating device, the high-pressure steam input end is connected to the external first high-pressure raw steam pipeline, and the output end of the steam ejector is connected to the input end of the steam separation device.

5. The flash steam heat recovery system according to claim 2, characterized in that: The flash steam heat recovery system also includes a condensate water tank, a first input end of the condensate water tank is connected to the condensate main pipe, and a second input end of the condensate water tank is connected to the discharge end of the circulation pump.

6. The flash steam heat recovery system according to claim 5, characterized in that: The steam separation device is provided with two input ends, namely a secondary heating steam input end and a spare input end. The secondary heating steam input end of the steam separation device is connected to the output end of the second heating device, and the spare input end of the steam separation device is connected to the external second high-pressure raw steam pipeline.

7. The flash steam heat recovery system according to claim 6, characterized in that: The condensate main pipe and the condensate input end are connected through a first pipe, and a first regulating valve is provided on the first pipe; The condensate main pipe and the first input end of the condensate tank are connected through a second pipe, and a second regulating valve is provided on the second pipe; The discharge end of the circulation pump and the second input end of the condensate water tank are connected through a third pipeline, and a third regulating valve is provided on the third pipeline; The output end of the second heating device and the secondary heating steam input end of the steam separation device are connected through a fourth pipeline, and a fourth regulating valve is provided on the fourth pipeline; The second circulation pipeline is provided with a fifth regulating valve, the first high-pressure raw steam pipeline is provided with a sixth regulating valve, and the second high-pressure raw steam pipeline is provided with a seventh regulating valve.

8. The flash steam heat recovery system according to claim 1, characterized in that: The condensed water output end, the condensed water input end, the circulating water recovery end, the separation liquid recovery end and the flash steam output end are sequentially arranged in the condensed water collection tank from bottom to top; The height difference between the condensate output end and the circulating water recovery end is h1, the total height of the condensate collection tank is h2, and h1 and h2 satisfy the following formula: h1=(0.5-0.9)h2.

9. A flash steam heat recovery method, characterized in that: The flash steam heat recovery system according to any one of claims 1 to 8 comprises the following steps: (1) Condensed water is passed into a condensed water collection tank to generate flash steam in the condensed water collection tank; the condensed water in the condensed water collection tank is circulated by a circulating pump; the temperature of the flash steam is 80 to 100° C.; (2) heating the flash steam generated in the condensate collection tank for the first time to obtain primary heated steam; the primary heated steam has a temperature of 100° C. to 140° C. and a pressure of saturated steam at 100° C. to 140° C.; (3) heating the primary heated steam again to obtain secondary heated steam; the secondary heated steam has a temperature of 120° C. to 200° C. and a pressure of saturated steam at 120° C. to 200° C.; (4) The secondary heated steam is input into a steam separation device, and distributed to steam-consuming equipment through the steam separation device.

10. The flash steam heat recovery method according to claim 9, characterized in that: In step (2), the flash steam is heated for the first time by using a steam compressor to obtain primary heated steam; In step (3), the primary heated steam is heated again by introducing raw steam to obtain secondary heated steam; the temperature of the raw steam is 200°C to 300°C.

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