Combined evaporation device

Abstract

The utility model discloses a combined evaporation device capable of carrying out natural flash evaporation and MVR (Mechanical Vapor Recompression) evaporation. The device is composed of a self-evaporation flash evaporator, an MVR evaporator, a vapor compression fan, a surface condenser, an evaporation and condensation water tank, a vacuum pump and the like, a high-temperature material supply pipe is connected with the material input end of the flash evaporator, the secondary vapor output end of the flash evaporator is communicated with the input end of the surface condenser through a pipeline, and the non-condensable gas output end of the surface condenser is communicated with the vacuum pump; the material output end of the self-evaporation flash evaporator is communicated with the material input end of the MVR evaporator through a pipeline, a control valve is arranged on the self-evaporation flash evaporator and the material input end of the MVR evaporator, the material output end of the MVR evaporator is connected with the discharging pump, and a non-condensable gas exhaust port of the MVR evaporator is communicated with the input end of the surface condenser. According to the device, obvious pressure and temperature gradient can be formed between the flash evaporator and the surface condenser, a stable and reliable self-evaporation phenomenon is maintained, and meanwhile, a large amount of moisture in a material to be treated can be removed.

Description

Technical Field

[0001] The utility model relates to a device for pre-treating materials discharged from industrial production at high temperatures and high flow rates. The high-temperature materials herein are liquid materials that are difficult to store under normal pressure; high flow rates refer to materials with large storage volumes, requiring the construction of large storage tanks. This pre-treatment device is designed to lower the temperature and reduce the volume of these materials before final processing. Background Art

[0002] Evaporation devices are widely used in daily life and industrial production. The required process objectives are different, the treatment effects achieved are also diverse, and the initial conditions of the materials to be treated are even more diverse and complex.

[0003] The materials generated in certain industrial production processes are very hot. If stored in pressure tanks, the storage conditions must be very strict. The manufacturing and maintenance costs of the equipment, as well as the difficulty of subsequent processing, will be greatly increased, which is not conducive to cost control, efficient production, and improved competitiveness. If stored in atmospheric pressure tanks, a significant pressure and temperature difference will be formed between the material to be processed and the environment, and the material is prone to violent flash evaporation, that is, self-evaporation and the generation of a large amount of secondary steam. Although this secondary steam has a high calorific value, it is difficult to effectively utilize. Currently, in some practical applications, the temperature of the material to be evaporated is very high and the total amount is also large. The high temperature means that atmospheric pressure storage conditions are difficult to meet the requirements, and the large amount means that a large storage tank is required to maintain stable production. On the other hand, how to fully utilize the thermal energy of the material to be processed is also a problem that needs to be solved. Summary of the Invention

[0004] The utility model provides a combined evaporation device which can solve the problems existing in the prior art and can fully utilize the heat energy of high-temperature liquid materials.

[0005] The utility model comprises a combined evaporation device, comprising: a self-evaporating flash evaporator, an MVR evaporator, a surface condenser, a steam compression blower, an evaporation condensation water tank, a vacuum pump, and pipelines and pumps for connecting various devices. The utility model is characterized in that a material feed pipe is connected to the feed end of the flash evaporator, a feed control valve is provided on the material feed pipe, the secondary steam output end of the flash evaporator is connected to the input end of the surface condenser via a flash secondary steam pipe, the non-condensable gas outlet end of the surface condenser is connected to the air inlet end of the vacuum pump, the air outlet end of the vacuum pump is connected to the non-condensable gas discharge pipe, and the discharge end of the flash evaporator is connected to the feed end of the MVR evaporator. The secondary steam output end of the MVR evaporator is connected to the air inlet end of the steam compressor through the MVR secondary steam pipe. The steam input heating end of the MVR evaporator is respectively connected to the compressor outlet end and the low-pressure steam supply pipe. The non-condensable gas discharge end of the MVR evaporator is connected to the surface condenser input end through an MVR non-condensable gas exhaust pipe with a control valve provided thereon. The condensate discharge port of the MVR evaporator is connected to the MVR condensate tank. The exhaust port of the MVR condensate tank is connected to the air inlet end of the steam compressor. The MVR evaporator is also provided with an MVR material circulation pipe and an MVR evaporator circulation pump.

[0006] Preferably, the working liquid level of the MVR evaporator in the combined evaporation device of the present invention is lower than the working liquid level of the flash evaporator, so that the material after natural flash evaporation can flow into the MVR evaporator by gravity, and a liquid inlet control valve is provided on the connecting pipeline connecting the discharge end of the flash evaporator and the feed end of the evaporator.

[0007] First, the device of the present invention is provided with a self-evaporating flash evaporator, and is equipped with a surface condenser and a vacuum system, so that a significant pressure and temperature gradient is formed between the flash evaporator and the surface condenser, prompting the system to maintain a stable and reliable self-evaporation phenomenon, thereby achieving natural flash evaporation and cooling the material to be processed. Secondly, in the present invention, after installation, a certain height difference is formed between the working liquid level of the flash evaporator and the MVR evaporator equipment. After natural flash evaporation, the material flows into the MVR evaporator by gravity. The discharge volume is automatically adjusted by the valve according to the production situation. After entering the MVR evaporator, the MVR evaporator performs pre-concentration treatment to remove a large amount of water in the material to be processed, so that the concentration of the material to be processed is increased. After the total amount is greatly reduced, it is sent to the next stage to continue to complete the set process goals.

[0008] The condensed water produced by MVR evaporation is discharged and stored in the MVR condensed water tank. Since there is a certain temperature difference between the condensed water and the MVR secondary steam, in the utility model, the exhaust port of the MVR condensed water tank is connected to the steam pipe at the inlet of the steam compressor, so that the flash evaporation conditions of the condensed water are met, forming the flash evaporation phenomenon of the condensed water. These flash steam and the MVR secondary steam are mixed and heated and pressurized by the steam compressor, and then returned to the MVR evaporator for use as a heat source. The temperature of the MVR condensed water drops after flash evaporation, which can better meet the pumping conditions. At the same time, the secondary steam formed by the flash evaporation is well utilized.

[0009] In the utility model, the MVR evaporation system is no longer equipped with a separate surface condenser, but shares the surface condenser with the natural evaporation flash evaporator. The waste heat steam entrained with air and non-condensable gases enters the surface condenser for centralized treatment, and the exhaust intensity of the MVR is precisely controlled by the exhaust valve.

[0010] Since the working liquid level of the MVR evaporator 17 in the combined evaporation device of the present invention is lower than that of the flash evaporator, the material evaporated in the flash evaporator can flow into the MVR evaporator by gravity. At the same time, since a liquid inlet control valve is provided on the connecting pipe connecting the discharge end of the flash evaporator and the feed end of the evaporator, this arrangement allows the material evaporated by natural flash evaporation to flow into the MVR evaporator by gravity. The discharge amount can be automatically adjusted by the liquid inlet control valve according to production conditions, thereby facilitating process control and production regulation.

[0011] The device of the present invention is provided with a flash evaporator capable of self-evaporation, and is also equipped with a surface condenser and a vacuum system. This allows the high-temperature steam to form a significant pressure and temperature gradient between the flash evaporator and the surface condenser, thereby forming a self-evaporation flash evaporation process, which enables the system to maintain a stable and reliable self-evaporation phenomenon, thereby allowing the material to be cooled by natural flash evaporation, facilitating the storage and subsequent processing of the material. At the same time, the water content of the material is reduced after flash evaporation, thereby increasing its concentration and improving the efficiency of subsequent concentration processing. On the other hand, the cooling water entering the surface condenser is heated and can be used as a heat source for the required process sections, thereby fully utilizing the thermal energy. The non-condensable gas outlet of the MVR evaporator of the present invention is connected to the input end of the surface condenser. Such a structure uses the same surface condenser, so that the air entrained by the waste heat steam and the non-condensable gas generated by the MVR evaporator are introduced into the surface condenser for centralized treatment. In addition, a control exhaust valve is provided between the non-condensable gas outlet of the MVR evaporator and the input end of the surface condenser. The exhaust intensity of the MVR evaporator can be precisely controlled by controlling the exhaust valve, reducing the repeated settings of the equipment, making the structure compact, and greatly simplifying the control link.

[0012] The condensed water generated in the MVR evaporator of the utility model is discharged and stored in the MVR condensed water tank. Since there is a certain temperature difference between the condensed water and the MVR secondary steam, the exhaust port of the MVR condensed water tank is connected to the steam pipe of the steam compressor inlet. In this way, the MVR condensed water tank meets the flash evaporation conditions of the condensed water therein, so that the condensed water therein flash evaporates. The steam generated by the flash evaporation is mixed with the MVR secondary steam and then heated and pressurized by the steam compressor and returned to the MVR evaporator for use as a heat source. The temperature of the MVR condensed water drops after the flash evaporation, which can not only meet the pumping conditions, but also make full use of the heat energy of the secondary steam formed by the flash evaporation. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Attachment Figure 1 This is a schematic diagram of an embodiment of the present invention, which is specifically applied to the treatment of papermaking black liquor with a relatively high temperature.

[0014] In the figure: 1 is the feed pipe for high-temperature materials (i.e., high-temperature liquid materials that need to be pretreated), 2 is the feed control valve, 3 is the flash evaporator, 4 is the flash secondary steam pipe, 5 is the surface condenser, 6 is the surface cooling drain pipe, 7 is the surface cooling condensate tank, 8 is the surface cooling condensate pump, 9 is the surface cooling condensate feed pipe, 10 is the surface cooling cooling water return pipe, 11 is the surface cooling cooling water supply pipe, 12 is the vacuum pump, 13 is the non-condensable gas outlet pipe, 14 is the non-condensable gas discharge pipe, 15 is the feed pipe for the liquid to be treated, 16 is the MVR liquid inlet control valve, 17 is the MVR Evaporator, 18 is the MVR evaporator circulation pump, 19 is the MVR secondary steam pipe, 20 is the steam compressor, 21 is the compressor outlet steam pipe, 22 is the low-pressure steam control valve, 23 is the low-pressure steam supply pipe, 24 is the electronically controlled exhaust control valve, 25 is the MVR non-condensable gas exhaust pipe, 26 is the MVR condensate discharge pipe, 27 is the MVR condensate tank, 28 is the MVR condensate pump, 29 is the MVR condensate delivery pipe, 30 is the MVR condensate flash steam outlet pipe, 31 is the MVR discharge pump, and 32 is the MVR discharge delivery pipe. DETAILED DESCRIPTION

[0015] The present invention is explained in detail with reference to the accompanying drawings and specific embodiments.

[0016] In the device of the present utility model, see the attached Figure 1The material feed pipe 1 is connected to the feed end of the flash evaporator 3 and is equipped with a feed control valve 2. The secondary steam output end of the flash evaporator 3 is connected to the input end of the surface condenser 5 via a flash secondary steam pipe 4. The non-condensable gas outlet end of the surface condenser 5 is connected to the air inlet end of the vacuum pump 12 via a non-condensable gas outlet pipe 13. The air outlet end of the vacuum pump 12 is connected to a non-condensable gas discharge pipe 14. The discharge end of the flash evaporator 3 and the feed end of the MVR evaporator 17 are connected to each other through a gravity pipe 15, which allows the treated liquid to enter the MVR evaporator. The gravity pipe 15 is equipped with a liquid inlet control valve 16, which precisely controls the feed flow rate. The discharge end of the flash evaporator 3 is connected to the feed end of the MVR evaporator 17. The operating liquid level of the MVR evaporator 17 is set lower than that of the flash evaporator 3. The secondary steam output end of the MVR evaporator 17 is connected to the air inlet end of the steam compressor 20 via an MVR secondary steam pipe 19. The steam input heating end of the MVR evaporator 17 is respectively connected to the outlet end of the compressor 20 and the low-pressure steam supply pipe 23. The non-condensable gas discharge end of the MVR evaporator 17 is connected to the input end of the surface condenser 5 via an MVR non-condensable gas exhaust pipe 25 provided with a control valve 24. The condensate discharge port of the MVR evaporator 17 is connected to the MVR condensate tank 27. The exhaust port of the MVR condensate tank 27 is connected to the air inlet end of the steam compressor 20. The MVR evaporator 17 is also provided with an MVR material circulation pipe and an MVR evaporator circulation pump 18.

[0017] When the utility model is in operation, black liquor with a relatively high temperature is pumped in by the pulp line and enters the flash evaporator 3 from the material feeding pipe 1 to be processed through the feed control valve 2. Due to the joint action of auxiliary systems such as the surface condenser 5 and the vacuum pump 12, an obvious pressure and temperature gradient is formed between the flash evaporator 3 and the surface condenser 5, forcing the black liquor entering the flash evaporator 3 to form a strong flash evaporation phenomenon, generating a certain amount of secondary steam, and at the same time, the temperature of the liquid itself is reduced and the concentration is increased. After flash evaporation, black liquor flows by gravity from the treated liquid inlet MVR evaporator gravity pipe 15 into the MVR evaporator 17. The feed rate is precisely controlled by the MVR liquid inlet control valve 16. After flash evaporation, the black liquor, with its temperature lowered and concentration increased, is delivered to the bottom of the MVR evaporator 17. A circulating pump 18 delivers this black liquor to the upper surface of the heating element within the MVR evaporator 17, where it forms a uniform film and flows downward, exchanging heat with steam from the steam compressor 20. The steam condenses to form condensate, which is discharged through the MVR condensate discharge pipe 26 and into the MVR condensate tank 27. The black liquor in the MVR evaporator 17 boils due to the heat, generating secondary steam, which is discharged through the MVR secondary steam pipe 19. After entering the steam compressor 20, the steam performs mechanical work, forcing the steam temperature and pressure to rise. The steam then enters the MVR evaporator 20 through the compressor outlet steam pipe 21, where it undergoes further heat exchange with the black liquor, resulting in a continuous and stable evaporation process.

[0018] After heat exchange, the majority of the secondary steam in the MVR evaporator is condensed and discharged as condensed water. A small amount of residual heat steam, along with air and non-condensable gases, is discharged through the MVR non-condensable gas exhaust pipe 25. It mixes with the secondary steam from the flash evaporator 3 and enters the surface condenser 5. The steam is cooled by cooling water, and the non-condensable gases and air are pumped out by a vacuum pump to other processing sections for centralized treatment. This ensures that the air and non-condensable gases in the MVR evaporator are continuously discharged from the system, creating stable and reliable evaporation conditions and ensuring efficient evaporation.

[0019] Black liquor concentration gradually increases within MVR evaporator 17. Once it reaches the process setpoint, it is discharged by MVR discharge pump 31 and conveyed through MVR discharge pipe 32 to other processing stages. MVR evaporation offers extremely high evaporation efficiency and very low operating costs. The discharged black liquor flow rate is significantly reduced, and its temperature is lowered, creating favorable conditions for subsequent processing.

[0020] The condensate produced by the MVR evaporator of this utility model is collected in the MVR condensate tank 27 and flash evaporates. The resulting secondary steam, along with the MVR evaporation secondary steam, enters the steam compressor 20, where it is further heated and pressurized before being returned to the evaporator for use as a heat source for evaporation. The temperature of the MVR condensate drops after flash evaporation, making it more suitable for pumping. The secondary steam generated by the flash evaporation is also effectively utilized. The condensate is pumped out by the MVR condensate pump 28 and delivered through the MVR condensate delivery pipe 29 to various water-using processes, fully utilizing the thermal energy.

Claims

1. A combined evaporation device comprising: The self-evaporation flash evaporator, MVR evaporator, surface condenser, steam compression fan, evaporation condensation water tank and pipelines and pumps for connecting various equipment are characterized in that the material feed pipe is connected to the feed end of the flash evaporator, the material feed pipe is provided with a feed control valve, the secondary steam output end of the flash evaporator is connected to the input end of the surface condenser through a flash secondary steam pipe, the non-condensable gas outlet end of the surface condenser is connected to the air inlet end of the vacuum pump, the air outlet end of the vacuum pump is connected to the non-condensable gas discharge pipe, and the discharge end of the flash evaporator is connected to the feed end of the MVR evaporator. The secondary steam output end of the MVR evaporator is connected to the air inlet end of the steam compressor through the MVR secondary steam pipe. The steam heating end of the MVR evaporator is connected to the compressor outlet end and the low-pressure steam supply pipe respectively. The non-condensable gas discharge end of the MVR evaporator is connected to the surface condenser input end through an MVR non-condensable gas exhaust pipe with a control valve provided thereon. The condensate discharge port of the MVR evaporator is connected to the MVR condensate tank. The exhaust port of the MVR condensate tank is connected to the air inlet end of the steam compressor. The MVR evaporator is also provided with a material circulation pipe and an MVR evaporator circulation pump.

2. The combined evaporation device according to claim 1, characterized in that The working liquid level of the MVR evaporator is set lower than the working liquid level of the flash evaporator, so that the material after natural flash evaporation can flow into the MVR evaporator by gravity. A liquid inlet control valve is provided on the connecting pipe connecting the discharge end of the flash evaporator and the feed end of the evaporator.

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