Wheat starch process wastewater mvr evaporation system

Abstract

The application discloses a kind of wheat starch process wastewater MVR evaporation system, including material tank, delivery pump, evaporation device, steam compressor, surface condenser, vacuum pump set, steam delivery pipeline, condensate tank and discharge pipeline, the present application is using mechanical steam re-compression technology in vacuum state to the wheat starch process wastewater is evaporated concentration, under vacuum state, it can effectively reduce the boiling point of process wastewater, so it can be evaporated concentration at lower temperature, simultaneously using mechanical steam re-compression technology secondary steam separated from evaporator is pressurized and heated again as heat source, the primary steam provided by steam source only does supplementary use, to effectively reduce the use amount of primary steam, reduce energy consumption, in addition, using multiple parallel arrangement evaporator, can effectively improve evaporation intensity and evaporation efficiency, reduce equipment investment cost, to effectively reduce enterprise production cost, improve enterprise market competitiveness.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wheat starch production equipment, and particularly relates to a wheat starch process wastewater MVR evaporation system used when process wastewater generated in the production of wheat starch is evaporated and concentrated. BACKGROUND

[0002] Wheat starch is extracted from wheat, and is mainly used as a thickening agent, gelling agent, binding agent or stabilizer in food, and is also used to produce starch sugar.

[0003] In the production process of wheat starch, a large amount of wastewater is generated in the separation, washing and drying processes, which is collectively referred to as process wastewater. The wastewater contains a large amount of organic matter such as starch, soluble protein, sugar and cellulose. Therefore, if the wheat starch process wastewater is directly discharged, it will inevitably pollute the water body and further cause serious environmental pollution. At present, the wheat starch process wastewater usually needs to be discharged after being purified by a sewage treatment system through flocculation sedimentation or biological decomposition. However, the production of wheat starch consumes a lot of water resources. A wheat starch production enterprise with a capacity of 300,000 tons / year generates about 1,000 m 3 / day of process wastewater, which has a higher requirement for the treatment capacity of the sewage treatment system matched by the enterprise. The cost of the corresponding sewage treatment system and its operation cost are very high and difficult. The starch and protein in the wheat starch process wastewater are purified, causing resource waste.

[0004] Therefore, the existing wheat starch production enterprises evaporate and concentrate the wheat starch process wastewater through an evaporation concentration process to recover the organic matter such as starch and protein in the wastewater. The recovered organic matter can be used to produce industrial starch glue and other products, realizing the recycling of organic matter, reducing the investment and use cost of the sewage treatment equipment, effectively reducing the production cost of the enterprise and improving the market competitiveness of the enterprise. At present, when the wheat starch process wastewater is evaporated and concentrated, a multiple-effect evaporator is usually used. The multiple-effect evaporator is provided with multiple evaporators connected in series. Except that the first evaporator uses live steam to evaporate and concentrate the wheat starch process wastewater, the remaining evaporators use the secondary steam generated by the previous evaporator to evaporate and concentrate the wheat starch process wastewater. Since the process wastewater generated by the wheat starch is very much, and the water content in the process wastewater is too high, the concentration is only about 5%, which leads to the need for a large volume of evaporator and a large amount of steam during the evaporation and concentration of the wheat starch process wastewater, resulting in high evaporation and concentration cost. Moreover, as the concentration of the wheat starch process wastewater increases during the evaporation and concentration, the temperature also increases, making the evaporation and concentration difficult and the evaporation efficiency low. SUMMARY

[0005] In summary, in order to overcome the deficiencies of the prior art, the present application provides a wheat starch process wastewater MVR evaporation system, which utilizes mechanical steam recompression technology to evaporate and concentrate the wheat starch process wastewater under vacuum state, which can effectively reduce the boiling point of the process wastewater, so that it can be evaporated and concentrated at a lower temperature, and the secondary steam separated from the evaporator is pressurized and heated to be used as a heat source again by using mechanical steam recompression technology, and the primary steam provided by the steam source is only used for supplement, thereby effectively reducing the use amount of the primary steam, reducing energy consumption, in addition, the use of multiple parallel arranged evaporators can effectively improve the evaporation intensity and evaporation efficiency, reduce the equipment investment cost, thereby effectively reducing the production cost of enterprises and improving the market competitiveness of enterprises.

[0006] To solve the above technical problems, the technical scheme adopted by the present application is:

[0007] A wheat starch process wastewater MVR evaporation system, comprising a material tank, a conveying pump, an evaporation device, a steam compressor, a surface condenser, a vacuum pump set, a steam conveying pipeline, a condensate tank and a discharge pipeline,

[0008] The material tank is used for collecting and storing the wheat starch process wastewater,

[0009] The conveying pump is used for conveying the process wastewater in the material tank into the evaporation device, the inlet of the conveying pump is connected to the outlet of the material tank through a pipeline, and the outlet of the conveying pump is connected to the inlet of the evaporation device through a feeding pipeline,

[0010] The evaporation device is used for evaporating and concentrating the process wastewater by using primary steam or compressed steam, and the evaporation device comprises multiple parallel arranged evaporators, the inlets of the multiple evaporators are respectively connected to the compressed steam pipeline through pipelines, the outlets of the multiple evaporators are respectively connected to the gas return pipeline through pipelines, the inlets of the multiple evaporators are connected to the feeding pipeline, the outlet of one of the multiple evaporators is connected to the inlet of the discharge pump, and the outlet of the discharge pump is connected to the discharge pipeline,

[0011] The steam compressor is used for recompressing the secondary steam generated by the multiple evaporators of the evaporation device to make it pressurized and heated into high-grade compressed steam, the outlet of the steam compressor is connected to the inlets of the multiple evaporators of the evaporation device through the compressed steam pipeline, the inlet of the steam compressor is connected to the outlets of the multiple evaporators of the evaporation device through the gas return pipeline, and the airtight inlet of the steam compressor is connected to the steam source through the steam conveying pipeline,

[0012] The steam conveying pipeline is used for conveying the primary steam, the inlet of the steam conveying pipeline is connected to the steam source, and the steam conveying pipeline is connected to the compressed steam pipeline through the gas supplement pipeline,

[0013] A surface condenser is arranged to condense the non-condensable gas generated by the evaporation device, the gas inlet of the surface condenser is connected to the gas outlet of the evaporation device, and the gas outlet of the surface condenser is connected to the gas inlet of the vacuum pump group,

[0014] The vacuum pump group is arranged to provide power for the flow of the non-condensable gas, and the gas outlet of the vacuum pump group is arranged to be connected to a vacuum outlet,

[0015] A condensate tank is arranged to collect and store the condensate, the water inlet of the condensate tank is connected to the condensate outlets of the plurality of evaporators of the evaporation device, the condensate outlet of the non-condensable gas preheater and the condensate outlet of the surface condenser, and the water outlet of the condensate tank is connected to the water inlet of a condensate pump, and the condensate pump is arranged to transport the condensate.

[0016] The technical scheme of the present application can also be implemented as follows: the evaporation device comprises a first evaporator, a second evaporator and a third evaporator arranged in parallel, the first evaporator and the second evaporator are identical in structure and each comprises a heater A, a heater B, a separator, a circulating pump A and a circulating pump B, the gas inlets of the heater A and the heater B are respectively connected to the compressed steam pipeline through pipelines, the feed inlets of the heater A and the heater B are respectively connected to the feed pipeline through pipelines, the circulating outlet of the heater A is connected to the feed inlet of the circulating pump A through a pipeline, the outlet of the circulating pump A is connected to the circulating inlet of the heater A through a pipeline, the circulating outlet of the heater B is connected to the feed inlet of the circulating pump B through a pipeline, the outlet of the circulating pump B is connected to the circulating inlet of the heater B through a pipeline, the outlets of the heater A and the heater B are connected to the feed inlet of the separator, and the gas outlet of the separator is connected to the gas inlet of the steam compressor through a pipeline, and the outlet of the separator is connected to the feed inlet of the circulating pump A or the circulating pump B.

[0017] The technical scheme of the present application can also be implemented as follows: the third evaporator comprises a third heater, a third separator and a third circulating pump, the gas inlet of the third heater is connected to the compressed steam pipeline through a pipeline, the feed inlet of the third heater is connected to the feed pipeline through a pipeline, the outlet of the third heater is connected to the feed inlet of the third separator, the circulating outlet of the third heater is connected to the feed inlet of the third circulating pump through a pipeline, the outlet of the third circulating pump is connected to the circulating inlet of the third heater through a pipeline, the outlet of the third separator is connected to the feed inlet of the third circulating pump, and the gas outlet of the third separator is connected to the gas inlet of the steam compressor through a pipeline.

[0018] The technical scheme of the present application can also be implemented in the following manner: the separators of the first evaporator and the second evaporator are identical in structure to the third separator of the third evaporator, and each comprises a separator shell, a separator feed inlet, a separator gas outlet pipe and a defoaming device; the separator shell is provided with the separator feed inlet; the separator feed inlet of the third separator is connected to the outlet of the third heater; the separator feed inlet of the separator of the first evaporator is connected to the outlets of the heater A and the heater B of the first evaporator; the separator feed inlet of the separator of the second evaporator is connected to the outlets of the heater A and the heater B of the second evaporator; the defoaming device is arranged at the upper portion of the separator shell; the defoaming device divides the inner cavity of the separator shell into an upper gas outlet cavity and a lower outlet cavity; the outlet cavity is provided with a separator outlet; the separator shell is provided with a separator gas outlet pipe; the separator gas outlet pipe is arranged from top to bottom along the height direction of the separator shell; the gas inlet of the separator gas outlet pipe is located in the separator gas outlet cavity; the gas outlet of the separator gas outlet pipe is connected to the gas inlet of the steam compressor through a gas return pipeline; the separator outlet of the third separator of the third evaporator is connected to the feed inlet of the third circulating pump through a pipeline; the separator outlet of the separator of the first evaporator is connected to the feed inlet of the circulating pump A or the circulating pump B of the first evaporator through a pipeline; and the separator outlet of the separator of the second evaporator is connected to the feed inlet of the circulating pump A or the circulating pump B of the second evaporator through a pipeline.

[0019] The technical scheme of the present application can also be implemented in the following manner: a flushing nozzle is arranged in the gas outlet cavity of the separator shell; the flushing nozzle is connected to a condensate water main through a flushing pipeline; and the condensate water main is connected to the water outlet of a condensate water pump.

[0020] The technical scheme of the present application can also be implemented in the following manner: the condensate water main is connected to the spray water inlet of the steam compressor through a cooling spray pipeline, or a cooling spray nozzle is arranged in the compressed steam pipeline; the condensate water main is connected to the cooling spray nozzle through a cooling spray pipeline; and a cooling spray valve is arranged on the cooling spray pipeline.

[0021] The technical scheme of the present application can also be implemented in the following manner: a liquid level transmitter is arranged on the third heater of the third evaporator; a feed adjusting valve is arranged on the feed pipeline connected to the outlet of the delivery pump; and the feed adjusting valve is controlled by the liquid level transmitter.

[0022] The technical scheme of the present application can also be implemented in the following manner: a preheating system is arranged between the discharge port of the delivery pump and the evaporation device, the preheating system preheats the wheat starch process wastewater by using condensate water and non-condensed gas, the preheating system comprises a condensate water preheating device, a first-stage non-condensed gas preheater and a second-stage non-condensed gas preheater, the condensate water preheating device comprises a plurality of plate heat exchangers arranged in parallel, the feed ports of the plurality of plate heat exchangers are respectively connected to the discharge port of the delivery pump through pipelines, the discharge ports of the plurality of plate heat exchangers are respectively connected to the feed port of the second-stage non-condensed gas preheater through pipelines, the water inlets of the plurality of plate heat exchangers are respectively connected to the water outlet of a condensate water pump through pipelines, the water outlets of the plurality of plate heat exchangers are all connected to a water outlet pipeline, the discharge port of the second-stage non-condensed gas preheater is connected to the feed port of the first-stage non-condensed gas preheater through a pipeline, the discharge port of the first-stage non-condensed gas preheater is connected to a feed pipeline, the gas inlet of the first-stage non-condensed gas preheater is connected to the non-condensed gas outlet of the evaporation device, the gas outlet of the first-stage non-condensed gas preheater is connected to the gas inlet of the second-stage non-condensed gas preheater, and the gas outlet of the second-stage non-condensed gas preheater is connected to the gas inlet of the surface condenser.

[0023] The technical scheme of the present application can also be implemented in the following manner: the material tank comprises two wastewater buffer tanks arranged in parallel, the discharge ports of the two wastewater buffer tanks are respectively connected to the feed port of the delivery pump through pipelines, and a stirring device is arranged in each of the wastewater buffer tanks.

[0024] The technical scheme of the present application can also be implemented in the following manner: the discharge pipeline comprises a discharge main pipe, a thick slurry discharge pipe, a cleaning water discharge pipe and a backflow pipe, the discharge port of the delivery pump is connected to the discharge main pipe, the thick slurry discharge pipe, the cleaning water discharge pipe and the backflow pipe respectively, the thick slurry discharge pipe is connected to the discharge main pipe and the finished product tank, the cleaning water discharge pipe is connected to the discharge main pipe and the sewage tank, and the backflow pipe is connected to the discharge main pipe and the material tank, a mass density meter is arranged on the discharge main pipe, a thick slurry discharge valve is arranged on the thick slurry discharge pipe, a cleaning water discharge valve is arranged on the cleaning water discharge pipe, a backflow valve is arranged on the backflow pipe, the thick slurry discharge valve, the cleaning water discharge valve and the backflow valve are controlled by the mass density meter, a flow sensor is arranged on the thick slurry discharge pipe, a total discharge valve is arranged on the discharge main pipe, and the total discharge valve is controlled by the flow sensor.

[0025] The technical scheme of the present application can also be implemented in the following manner: a steam flow sensor and a gas supplement valve are arranged on the gas supplement pipeline, a pressure transmitter is arranged on the heater A of the first-stage evaporator, and the gas supplement valve is controlled by the pressure transmitter.

[0026] The present application has the following beneficial effects:

[0027] 1. The application is to use mechanical vapor recompression technology in the vacuum state to the wheat starch process wastewater evaporation concentration, the boiling point of process wastewater can be effectively reduced in the vacuum state, so that it can be evaporated and concentrated at a lower temperature, and the secondary steam separated from the evaporator is pressurized and heated again by using mechanical vapor recompression technology to be used as a heat source, and the primary steam provided by the steam source 8 is only used as a supplement, thereby effectively reducing the use amount of primary steam, reducing energy consumption, in addition, using multiple parallel arranged evaporators can effectively improve the evaporation intensity and evaporation efficiency, reduce the equipment investment cost, thereby effectively reducing the enterprise production cost and improving the enterprise market competitiveness.

[0028] 2. The evaporation device of the application comprises a first evaporator, a second evaporator and a third evaporator, the first evaporator and the second evaporator adopt the structure of two heaters sharing one separator, compared with the traditional evaporator, the use amount of the separator is saved, thereby reducing the production cost of the system, the separator of the application is different from the traditional separator, a separation outlet pipe is arranged in the separation shell of the separator, the separation outlet pipe is arranged from top to bottom along the height direction of the separation shell, the gas inlet of the separation outlet pipe is located in the separation outlet cavity, the secondary steam separated by the separator enters from the gas inlet of the separation outlet pipe in the separation outlet cavity, flows downward directly through the guide of the separation outlet pipe and enters the gas return pipeline, and then enters the steam compressor for compression and heating, while the secondary steam outlet of the traditional separator is usually at the upper end of the shell, when the outlet is arranged at the upper end of the shell and communicates with the gas return pipeline, the pipeline arrangement is relatively complex, and a longer pipeline is needed, which increases the pipeline arrangement cost. Therefore, the evaporator of the application can effectively reduce the production cost of the equipment compared with the traditional evaporator, thereby reducing the cost investment of the enterprise, and the evaporation device of the application has compact structure and small floor space, thereby reducing the land cost of the enterprise.

[0029] 3. The separator of the first evaporator and the second evaporator and the separation shell of the third separator are all provided with a defoaming device, and a flushing nozzle is arranged, the defoaming device can prevent the entrainment of mist, and the defoaming device is sprayed and washed by the condensate water, which can effectively ensure the long-term and high-efficiency operation of the defoaming device.

[0030] 4、The evaporation device of the present application adopts three parallelly arranged evaporators, and the first-stage evaporator and the second-stage evaporator each comprises two heaters, so that the present application can evaporate and concentrate the wheat starch process wastewater through five heaters, the five heaters are parallelly arranged, and the five heaters are all in communication with the feed pipeline, so that the five heaters are interconnected, and the pressure and the liquid level in the entire evaporation device are balanced, the process wastewater is simultaneously fed into the five heaters for heating and concentration evaporation, the concentrated slurry after evaporation and concentration flows out from the third-stage heater, after the concentrated slurry flows out, in order to maintain the liquid level balance of the evaporation device, the process wastewater must flow in the system, and new process wastewater is supplemented into the evaporation device, so that the process wastewater evaporation and concentration is smoothly carried out. The three evaporators of the present application have five heaters in total, which simultaneously evaporate and concentrate the process wastewater, and through use, 60 tons of water can be evaporated from the process wastewater per hour, which can fully meet the needs of a wheat starch production enterprise with an annual production capacity of 300,000 tons, and the condensed water generated by evaporation can be reused, realizing the recycling of water resources, reducing the cost of enterprises, and in addition, if the evaporation capacity of the present application is to be further improved, more evaporators can be connected in parallel in the evaporation device.

[0031] 5、The present application sets up a preheating system, which uses condensed water and non-condensable gas to preheat the wheat starch process wastewater. Since the amount of the wheat starch process wastewater is very large, the condensed water preheater of the preheating system of the present application is set up as two parallelly arranged plate heat exchangers, which simultaneously preheat the process wastewater, so as to ensure the preheating efficiency and ensure the stable feeding of the subsequent evaporation device. In addition, since the heat source for evaporating and concentrating the process wastewater after the system is stably operated is compressed steam, the compressed steam is obtained by mechanically compressing secondary steam, and the secondary steam contains a small amount of impurities and materials, therefore, the evaporation device of the present application generates a large amount of non-condensable gas, and therefore, the preheating system of the present application sets up two serially connected non-condensable gas preheaters, i.e., a first-stage non-condensable gas preheater and a second-stage non-condensable gas preheater. The two serially connected non-condensable gas preheaters can fully recover the heat in the non-condensable gas, so as to improve the preheating efficiency, achieve the purpose of fully recovering waste heat, and reduce energy consumption.

[0032] 6、The total discharge pipe of the application is connected with the product tank, the sewage tank and the material tank through three pipes respectively. The mass density meter controls the thick slurry discharge valve, the cleaning water discharge valve and the reflux valve. When the mass density meter detects that the discharge concentration reaches the requirement, the thick slurry discharge valve is opened, and the thick slurry concentrated from the process wastewater is stored in the product tank. When the mass density meter detects that the concentration does not reach the requirement, the reflux valve is opened, and the concentrated process wastewater enters the application again for evaporation and concentration. When the application is cleaned, the cleaning water discharge valve is opened by the mass density meter to discharge the cleaning water into the sewage tank, and then into the sewage treatment system. The flow sensor is arranged on the thick slurry discharge pipe of the application, and the flow sensor controls the total discharge valve. The flow sensor detects the discharge amount of the thick slurry with the required concentration, and the size of the total discharge valve can be adjusted according to the requirement, so as to increase or reduce the discharge speed.

[0033] 7、The application sprays the condensed water to the steam compressor through the spraying pipe, or sprays the condensed water to the compressed steam pipe through the spraying pipe. When the steam temperature in the compressed steam pipe is too high, the sprayed condensed water enters the compressed steam pipe in the atomized state, and the atomized water droplets vaporize under the action of the overheated steam, so as to improve the saturation of the steam in the compressed steam pipe and reduce the steam temperature in the compressed steam pipe. The application connects the steam delivery pipe and the compressed steam pipe through the air supply pipe, and controls the air supply valve through the pressure transmitter on the heater A of the primary evaporator. When the pressure in the evaporation device is low, the air supply valve is opened to supply primary steam to the system, so as to ensure the steam temperature and pressure in the system and ensure the smooth and stable operation of the evaporation and concentration. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 It is a structural schematic diagram of the application;

[0035] Figure 2 It is a structural schematic diagram of the application; Figure 1 It is an enlarged structural schematic diagram of part A. DETAILED DESCRIPTION

[0036] The application will be further described in detail below with reference to the accompanying drawings.

[0037] As Figure 1 , Figure 2As shown, a wheat starch process wastewater MVR evaporation system includes a material tank 1, a conveying pump 2, an evaporation device, a steam compressor 7, a surface condenser 3, a vacuum pump set 4, a steam conveying pipeline 5, a condensate tank 6, and a discharge pipeline. The material tank 1 is used to collect and store the wheat starch process wastewater. The material tank 1 includes two wastewater buffer tanks arranged in parallel. The inlet of the two wastewater buffer tanks is connected to a process wastewater pipeline and a cleaning water source. The outlet of the two wastewater buffer tanks is respectively connected to the inlet of the conveying pump 2 through a pipeline. A stirring device is arranged in the wastewater buffer tank, which can prevent the impurities in the process wastewater from precipitating.

[0038] The preheating system uses condensate water and non-condensable gas to preheat the wheat starch process wastewater. The preheating system includes a condensate water preheating device 43, a first-stage non-condensable gas preheater 44, and a second-stage non-condensable gas preheater 45. The condensate water preheating device 43 includes a plurality of plate heat exchangers arranged in parallel. The inlet of the plate heat exchangers is respectively connected to the outlet of the conveying pump 2 through a pipeline. The outlet of the plate heat exchangers is respectively connected to the inlet of the second-stage non-condensable gas preheater 45 through a pipeline. The water inlet of the plate heat exchangers is respectively connected to the outlet of a condensate water pump 46 through a pipeline. The water outlet of the plate heat exchangers is connected to a water outlet pipeline. The outlet of the second-stage non-condensable gas preheater 45 is connected to the inlet of the first-stage non-condensable gas preheater 44 through a pipeline. The outlet of the first-stage non-condensable gas preheater 44 is connected to the inlet of the pipeline 16. The gas inlet of the first-stage non-condensable gas preheater 44 is connected to the non-condensable gas outlet of the evaporation device. The gas outlet of the first-stage non-condensable gas preheater 44 is connected to the gas inlet of the second-stage non-condensable gas preheater 45. The gas outlet of the second-stage non-condensable gas preheater 45 is connected to the gas inlet of the surface condenser 3. The non-condensable gas discharged from the second-stage non-condensable gas preheater 45 is condensed in the surface condenser 3. The gas outlet of the surface condenser 3 is connected to the gas inlet of the vacuum pump set 4. The gas outlet of the vacuum pump set 4 is vented. The vacuum pump set 4 provides power for the flow of non-condensable gas. The vacuum pump set 4 includes a vacuum pump, a washing tower, and a heat exchanger. The gas outlet of the surface condenser 3 is connected to the gas inlet of the vacuum pump. The gas outlet of the vacuum pump is connected to the gas inlet of the washing tower. The gas outlet of the washing tower is vented. The water outlet of the washing tower is connected to the heat exchanger. The washing water of the washing tower is cooled by cooling water. The non-condensable gas discharged from the surface condenser 3 is cooled by spraying and then discharged.

[0039] The feed pipeline 16 is connected to the evaporation device, which uses primary steam or compressed steam to evaporate and concentrate the process wastewater. The evaporation device includes three evaporators arranged in parallel, namely a first evaporator 13, a second evaporator 14, and a third evaporator 15. The first evaporator 13 includes a first heater A 131, a first heater B 132, a first separator 133, a first circulating pump A 134, and a first circulating pump B 135. The gas inlet of the first heater A 131 and the gas inlet of the first heater B 132 are connected to the compressed steam pipeline 10 through pipelines. The feed inlet of the first heater A 131 and the feed inlet of the first heater B 132 are connected to the feed pipeline 16 through pipelines. The circulating outlet of the first heater A 131 is connected to the feed inlet of the first circulating pump A through a pipeline. The outlet of the first circulating pump A 134 is connected to the circulating feed inlet of the first heater A 131 through a pipeline. The circulating outlet of the first heater B 132 is connected to the feed inlet of the first circulating pump B 135 through a pipeline. The outlet of the first circulating pump B 135 is connected to the circulating feed inlet of the first heater B 132 through a pipeline. The outlet of the first heater A 131 and the outlet of the first heater B 132 are connected to the feed inlet of the first separator 133. The gas outlet of the first separator 133 is connected to the gas inlet of the steam compressor 7 through a pipeline. The outlet of the first separator 133 is connected to the feed inlet of the first circulating pump A 134.

[0040] The second evaporator 14 includes a second heater A 141, a second heater B 142, a second separator 143, a second circulating pump A 144, and a second circulating pump B 145. The gas inlet of the second heater A 141 and the gas inlet of the second heater B 142 are connected to the compressed steam pipeline 10 through pipelines. The feed inlet of the second heater A 141 and the feed inlet of the second heater B 142 are connected to the feed pipeline 16 through pipelines. The circulating outlet of the second heater A 141 is connected to the feed inlet of the second circulating pump A through a pipeline. The outlet of the second circulating pump A 144 is connected to the circulating feed inlet of the second heater A 141 through a pipeline. The circulating outlet of the second heater B 142 is connected to the feed inlet of the second circulating pump B 145 through a pipeline. The outlet of the second circulating pump B 145 is connected to the circulating feed inlet of the second heater B 142 through a pipeline. The outlet of the second heater A 141 and the outlet of the second heater B 142 are connected to the feed inlet of the second separator 143. The gas outlet of the second separator 143 is connected to the gas inlet of the steam compressor 7 through a pipeline. The outlet of the second separator 143 is connected to the feed inlet of the second circulating pump A 144.

[0041] The third evaporator 15 comprises a third heater 151, a third separator 152 and a third circulating pump 153. The gas inlet of the third heater 151 is connected with the compressed steam pipeline 10 through a pipeline, the feed inlet of the third heater 151 is connected with the feed pipeline 16 through a pipeline, the feed outlet of the third heater 151 is connected with the feed inlet of the third separator 152, the circulating feed outlet of the third heater 151 is connected with the feed inlet of the third circulating pump 153 through a pipeline, the feed outlet of the third circulating pump 153 is connected with the circulating feed inlet of the third heater 151 through a pipeline, the feed outlet of the third separator 152 is connected with the feed inlet of the third circulating pump 153, and the gas outlet of the third separator 152 is connected with the gas inlet of the steam compressor 7 through a pipeline. A liquid level transmitter 18 is arranged on the third heater 151, a feed adjusting valve 17 is arranged on the feed pipeline 16 connected with the feed outlet of the delivery pump 2, and the feed adjusting valve 17 is controlled by the liquid level transmitter 18. The feed outlet of the third heater 151 in the third evaporator 15 is connected with the feed inlet of the delivery pump 11, the feed outlet of the delivery pump 11 is connected with a delivery pipeline, the delivery pipeline comprises a delivery main pipeline 19, a thick slurry delivery pipeline 20, a cleaning water delivery pipeline 21 and a backflow pipeline 22, the feed outlet of the delivery pump 11 is connected with the thick slurry delivery pipeline 20, the cleaning water delivery pipeline 21 and the backflow pipeline 22 through the delivery main pipeline 19, the thick slurry delivery pipeline 20 is connected with the delivery main pipeline 19 and a product tank 23, the cleaning water delivery pipeline 21 is connected with the delivery main pipeline 19 and a sewage tank 24, and the backflow pipeline 22 is connected with the delivery main pipeline 19 and the material tank 1. A mass density meter 25 is arranged on the delivery main pipeline 19, a thick slurry delivery valve 26 is arranged on the thick slurry delivery pipeline 20, a cleaning water delivery valve 27 is arranged on the cleaning water delivery pipeline 21, a backflow valve 28 is arranged on the backflow pipeline 22, the thick slurry delivery valve 26, the cleaning water delivery valve 27 and the backflow valve 28 are controlled by the mass density meter 25, a flow sensor 29 is arranged on the thick slurry delivery pipeline 20, and a total delivery valve 30 is arranged on the delivery main pipeline 19, the total delivery valve 30 is controlled by the flow sensor 29.

[0042] The first separator 133, the second separator 143 and the third separator 152 have the same structure and each include a separation shell 31, a separation inlet 32, a separation outlet 33 and a defoaming device 34. The separation inlet 32 is arranged on the separation shell 31. The separation inlet 32 of the third separator 152 is communicated with the outlet of the third heater 151. The separation inlet of the first separator 133 is communicated with the outlets of the first heater A 131 and the first heater B 132. The separation inlet of the second separator 143 is communicated with the outlets of the second heater A 141 and the second heater B 142. The defoaming device 34 is arranged in the upper part of the separation shell 31. The defoaming device 34 divides the inner cavity of the separation shell 31 into an upper gas outlet cavity 35 and a lower outlet cavity 36. The outlet cavity 36 is provided with a separation outlet 37. The separation outlet 33 is arranged in the separation shell 31. The separation outlet 33 is arranged from top to bottom along the height direction of the separation shell 31. The gas inlet of the separation outlet 33 is located in the separation outlet cavity 35. The gas outlet of the separation outlet 33 is communicated with the gas inlet of the steam compressor 7 through the gas return pipeline 12. The separation outlet 37 of the third separator 152 is communicated with the inlet of the third circulating pump 153 through a pipeline. The separation outlet 37 of the first separator 133 is communicated with the inlet of the first circulating pump A 134 through a pipeline. The separation outlet 37 of the second separator 143 is communicated with the inlet of the second circulating pump A 144 through a pipeline. The flushing nozzle 38 is arranged in the gas outlet cavity 35 of the separation shell 31. The flushing nozzle 38 is communicated with the condensate water main pipe 40 through the flushing pipeline 39. The flushing valve 47 is arranged on the flushing pipeline. The condensate water main pipe 40 is connected with the outlet of the condensate water pump 46.

[0043] The steam compressor 7 is communicated with the first separator 133, the second separator 143 and the third separator 152 through the gas return pipeline 12. The steam compressor 7 re-compresses the secondary steam separated by the first separator 133, the second separator 143 and the third separator 152 to form high-grade compressed steam. The gas outlet of the steam compressor 7 is communicated with the gas inlets of the first heater A 131, the first heater B 132, the second heater A 141, the second heater B 142 and the third heater 151 through the compressed steam pipeline 10. The airtight gas inlet of the steam compressor 7 is communicated with the steam source 8 through the steam conveying pipeline 5. The steam conveying pipeline 5 is used for conveying primary steam. The gas inlet of the steam conveying pipeline 5 is communicated with the steam source 8. The steam conveying pipeline 5 is communicated with the compressed steam pipeline 10 through the air supplement pipeline 9. The steam flow sensor and the air supplement valve 41 are arranged on the air supplement pipeline 9. The pressure transmitter 42 is arranged on the heater A of the first evaporator 13. The air supplement valve 41 is controlled by the pressure transmitter 42.

[0044] The water inlet of the condensate pump 46 is communicated with the water outlet of the condensate tank 6, the condensate tank 6 is used for collecting and storing the condensate, the water inlet of the condensate tank 6 is connected with the condensate outlets of the first heater A 131, the first heater B 132, the second heater A 141, the second heater B 142, the third heater 151, the first non-condensable gas preheater 44, the second non-condensable gas preheater 45 and the surface condenser 3 through pipelines respectively, in the embodiment, the condensate main pipe 40 is connected with the spraying water inlet of the steam compressor 7 through the cooling spraying main pipe, if the steam compressor 7 does not have the spraying water inlet, the cooling nozzle can be arranged in the compressed steam pipeline 10, the condensate main pipe 40 is communicated with the cooling nozzle through the cooling spraying pipeline, and the cooling spraying pipeline is provided with a cooling spraying valve.

[0045] In use, the conveying pump 2 is started, the wheat starch process wastewater with a concentration of about 5% stored in the wastewater buffer tank enters the condensate preheater under the action of the conveying pump 2, two parallel plate heat exchangers are used as the condensate preheater, the conveying pump 2 respectively passes the process wastewater into the two plate heat exchangers through pipelines, the two plate heat exchangers simultaneously preheat the process wastewater with the condensate for the first time, the process wastewater preheated by the condensate preheater firstly enters the second non-condensable gas preheater 45 to be preheated for the second time, and then enters the first non-condensable gas preheater 44 to be preheated for the third time, the first non-condensable gas preheater 44 preheats the process wastewater with the non-condensable gas generated by evaporation, and the second non-condensable gas preheater 45 preheats the process wastewater with the non-condensable gas discharged from the first non-condensable gas preheater 44.

[0046] The process wastewater after three preheats enters the first heater A 131, the first heater B 132, the second heater A 141, the second heater B 142 and the third heater 151 along the feed pipeline 16. When the system is just started, the primary steam provided by the steam source 8 enters the compressed steam pipeline 10 from the air supplement pipeline 9, and then enters the first heater A 131, the first heater B 132, the second heater A 141, the second heater B 142 and the third heater 151 along the compressed steam pipeline 10. In the first heater A 131, the primary steam evaporates and concentrates the process wastewater. The process wastewater flows along the tube of the first heater A 131 under the action of the first circulating pump A 134. The primary steam enters the shell of the first heater A 131 and is condensed into water after heat exchange with the process wastewater. The condensed water flows out of the first heater A 131 and enters the condensed water tank 6 for storage. The non-condensed gas generated enters the first non-condensed gas preheater 44 to preheat the process wastewater. The process wastewater in the first heater A 131 is evaporated and concentrated, and the generated secondary steam enters the gas return pipeline 12 along the separation gas pipeline 33 after defoaming in the first separator 133, and then enters the steam compressor 7 through the gas return pipeline 12. Similarly, in the first heater B 132, the second heater A 141, the second heater B 142 and the third heater 151, the process wastewater is evaporated and concentrated by the primary steam. The generated non-condensed gas enters the first non-condensed gas preheater 44 to preheat the process wastewater. The generated secondary steam enters the steam compressor 7 through the gas return pipeline 12. The steam compressor 7 compresses and heats the secondary steam to become compressed steam. The compressed steam enters the first heater A 131, the first heater B 132, the second heater A 141, the second heater B 142 and the third heater 151 through the compressed steam pipeline 10 to evaporate and concentrate the process wastewater. When the system gradually stabilizes, the pressure transmitter 42 in the first heater A 131 gradually reaches the design requirement. The pressure transmitter 42 adjusts the air supplement valve 41 to close or open. The primary steam no longer participates in heating, and only the compressed steam can evaporate and concentrate the process wastewater. When the compressed steam is consumed, the pressure transmitter 42 controls the air supplement valve 41 to open or adjust to supplement steam to the system to ensure the system pressure and temperature, so that the evaporation and concentration proceed smoothly.

[0047] Under the action of the discharge pump 11, the process wastewater circulating in the three-stage heater 151 is discharged into the discharge main 19, the mass density meter 25 detects the concentration of the process wastewater, when the concentration is concentrated to the designed concentration, the mass density meter 25 controls the thick slurry discharge valve 26 to open, the process wastewater concentrated into thick slurry enters the product tank 23 for storage through the thick slurry discharge pipe 20, the flow sensor 29 is arranged on the thick slurry discharge pipe 20, the flow sensor 29 controls the total discharge valve 30, the flow sensor 29 detects the discharge amount of the thick slurry with the required concentration, and the size of the total discharge valve 30 can be adjusted according to the requirement, so as to increase or reduce the discharge speed. When the concentration detected by the mass density meter 25 does not reach the requirement, the backflow valve 28 is opened, the process wastewater enters the material tank 1 through the backflow pipe 22, and the process wastewater with the substandard concentration enters the system again for evaporation and concentration, when the system is cleaned, the mass density meter 25 controls the cleaning water discharge valve 27 to open, the cleaning water enters the sewage tank 24 through the cleaning discharge pipe 21, and then is sent to the sewage treatment system,

[0048] After the process wastewater circulating in the three-stage heater 151 is discharged under the action of the discharge pump 11, the liquid level in the three-stage heater 151 is lowered, the five heaters of the present application are all communicated with the feed pipe 16, so the five heaters are also communicated with each other, and the liquid levels in the five heaters must be consistent, the process wastewater in the two-stage heater B 142 adjacent to the three-stage heater 151 must flow to the three-stage heater 151, and the process wastewater in the two-stage heater A 141 must flow to the two-stage heater B 142, the process wastewater in the one-stage heater B 132 must flow to the two-stage heater A 141, the process wastewater in the one-stage heater A 131 must flow to the one-stage heater B 132, and the feed pump 2 can supplement the process wastewater to the one-stage heater A 131, so that the liquid levels in the five heaters are consistent, and the flow of the process wastewater in the evaporation device is realized.

[0049] The steam conveying pipe 5 of the present application is communicated with the air-tight inlet of the steam compressor 7, and the steam is used to air-tightly seal the steam compressor 7. The water inlets of the two wastewater buffer tanks of the material tank 1 are also communicated with the water outlet of the condensate pump 46 through the pipe, when the concentration of the wastewater in the wastewater buffer tank is too high and the flowability is poor or the precipitation is generated, the condensate can be introduced into the wastewater buffer tank and stirred, so as to ensure the flowability of the process wastewater, and the process wastewater can flow in the system under the action of the feed pump 2.

[0050] It should be noted that the above-mentioned embodiments are the description of the technical scheme of the present application but not the limitation, the equivalent replacement of the ordinary technical personnel in the technical field or other modifications according to the prior art should be included in the scope of the right claimed by the present application, as long as it does not exceed the idea and range of the technical scheme of the present application.

Claims

1. A wheat starch process wastewater MVR evaporation system characterized by: The device comprises a material tank (1), a conveying pump (2), an evaporation device, a steam compressor (7), a surface condenser (3), a vacuum pump set (4), a steam conveying pipeline (5), a condensed water tank (6) and a discharge pipeline, The material tank (1) is used for collecting and storing wheat starch process wastewater, The conveying pump (2) is used for conveying the process wastewater in the material tank (1) into the evaporation device, the feeding port of the conveying pump (2) is connected with the discharge port of the material tank (1) through a pipeline, and the discharge port of the conveying pump (2) is connected with the feeding pipeline (16) of the evaporation device, The evaporation device is used for evaporating and concentrating the process wastewater by using primary steam or compressed steam, and comprises three evaporators arranged in parallel, the gas inlets of the three evaporators are connected with the compressed steam pipeline (10) through pipelines respectively, the gas outlets of the three evaporators are connected with the gas return pipeline (12) through pipelines respectively, the feeding ports of the three evaporators are connected with the feeding pipeline (16), the discharge port of one of the three evaporators is connected with the feeding port of the discharge pump (11), and the discharge port of the discharge pump (11) is connected with the discharge pipeline, The steam compressor (7) is used for re-compressing the secondary steam generated by the multiple evaporators of the evaporation device to make the secondary steam be compressed and heated to high-grade compressed steam, the gas outlet of the steam compressor (7) is connected with the gas inlets of the multiple evaporators of the evaporation device through the compressed steam pipeline (10), the gas inlet of the steam compressor (7) is connected with the gas outlets of the multiple evaporators of the evaporation device through the gas return pipeline (12), and the airtight gas inlet of the steam compressor (7) is connected with the steam source (8) through the steam conveying pipeline (5), The steam conveying pipeline (5) is used for conveying primary steam, the gas inlet of the steam conveying pipeline (5) is connected with the steam source (8), and the steam conveying pipeline (5) is connected with the compressed steam pipeline (10) through the air supplement pipeline (9), The surface condenser (3) is used for condensing the non-condensed gas generated by the evaporation device, the gas inlet of the surface condenser (3) is connected with the non-condensed gas outlet of the evaporation device, and the gas outlet of the surface condenser (3) is connected with the gas inlet of the vacuum pump set (4), The vacuum pump set (4) provides power for the flow of the non-condensed gas, and the gas outlet of the vacuum pump set (4) is exhausted, The condensed water tank (6) is used for collecting and storing condensed water, the water inlet of the condensed water tank (6) is connected with the condensed water outlets of the multiple evaporators of the evaporation device, the condensed water outlet of the non-condensed gas preheater and the condensed water outlet of the surface condenser (3), the water outlet of the condensed water tank (6) is connected with the water inlet of the condensed water pump (46), and the condensed water pump (46) is used for conveying condensed water, Three evaporators are respectively a first evaporator (13), a second evaporator (14) and a third evaporator (15), the first evaporator (13) and the second evaporator (14) are the same in structure, and each includes a heater A, a heater B, a separator, a circulating pump A and a circulating pump B, the air inlet of the heater A and the air inlet of the heater B are respectively communicated with the compressed steam pipeline (10) through pipelines, the feed inlet of the heater A and the feed inlet of the heater B are respectively communicated with the feed pipeline (16) through pipelines, the circulating outlet of the heater A is communicated with the feed inlet of the circulating pump A through a pipeline, the outlet of the circulating pump A is communicated with the circulating inlet of the heater A through a pipeline, the circulating outlet of the heater B is communicated with the feed inlet of the circulating pump B through a pipeline, the outlet of the circulating pump B is communicated with the circulating inlet of the heater B through a pipeline, the outlet of the heater A and the outlet of the heater B are both communicated with the feed inlet of the separator, the air outlet of the separator is connected with the air inlet of the steam compressor (7) through a pipeline, and the outlet of the separator is communicated with the feed inlet of the circulating pump A or the circulating pump B, The third evaporator (15) has a third separator (152), The separators of the first evaporator (13) and the second evaporator (14) and the third separator (152) of the third evaporator (15) are the same in structure, and each includes a separation shell (31), a separation feed inlet (32), a separation air outlet pipe (33) and a defoaming device (34), the separation shell (31) is provided with the separation feed inlet (32), the defoaming device (34) is arranged in the upper part of the separation shell (31), the defoaming device (34) divides the inner cavity of the separation shell (31) into an upper air outlet cavity (35) and a lower outlet cavity (36), the outlet cavity (36) is provided with a separation outlet (37), the separation air outlet pipe (33) is arranged in the separation shell (31) from top to bottom along the height direction of the separation shell (31), the air inlet of the separation air outlet pipe (33) is located in the separation air outlet cavity (35), and the air outlet of the separation air outlet pipe (33) is communicated with the air inlet of the steam compressor (7) through a return air pipeline (12).

2. A wheat starch process wastewater MVR evaporation system according to claim 1, characterized in that: The third evaporator (15) includes a third heater (151), a third separator (152) and a third circulating pump (153), the outlet of the third heater (151) is communicated with the feed inlet of the third separator (152), the circulating outlet of the third heater (151) is communicated with the feed inlet of the third circulating pump (153) through a pipeline, the outlet of the third circulating pump (153) is communicated with the circulating inlet of the third heater (151) through a pipeline, the outlet of the third separator (152) is communicated with the feed inlet of the third circulating pump (153), and the air outlet of the third separator (152) is communicated with the air inlet of the steam compressor (7) through the return air pipeline (12).

3. The wheat starch process wastewater MVR evaporation system of claim 1, wherein: The separation inlet (32) of the third separator (152) is communicated with the outlet of the third heater (151), the separation inlet of the separator of the first evaporator (13) is communicated with the outlets of the heater A and heater B of the first evaporator (13), the separation inlet of the separator of the second evaporator (14) is communicated with the outlets of the heater A and heater B of the second evaporator (14), the separation outlet (37) of the third separator (152) of the third evaporator (15) is communicated with the inlet of the third circulating pump (153) through a pipeline, the separation outlet (37) of the separator of the first evaporator (13) is communicated with the inlet of the circulating pump A or circulating pump B of the first evaporator (13) through a pipeline, and the separation outlet (37) of the separator of the second evaporator (14) is communicated with the inlet of the circulating pump A or circulating pump B of the second evaporator (14) through a pipeline.

4. The wheat starch process wastewater MVR evaporation system of claim 1, wherein: The flushing nozzle (38) is arranged in the gas outlet cavity (35) of the separation shell (31), and the flushing nozzle (38) is communicated with the condensate water main pipe (40) through a flushing pipeline (39), and the condensate water main pipe (40) is connected with the water outlet of the condensate water pump (46).

5. The wheat starch process wastewater MVR evaporation system of claim 2, wherein: The third heater (151) of the third evaporator (15) is provided with a liquid level transmitter (18), the inlet pipeline (16) connected with the outlet of the conveying pump (2) is provided with a feed adjusting valve (17), and the feed adjusting valve (17) is adjusted by the liquid level transmitter (18).

6. The wheat starch process wastewater MVR evaporation system of claim 1, wherein: The outlet of the conveying pump (2) and the evaporation device are provided with a preheating system, the preheating system preheats the wheat starch process wastewater by using condensate water and non-condensed gas, the preheating system comprises a condensate water preheating device (43), a first non-condensed gas preheater (44) and a second non-condensed gas preheater (45), the condensate water preheating device (43) comprises a plurality of parallelly arranged plate heat exchangers, the inlets of the plate heat exchangers are respectively communicated with the outlet of the conveying pump (2) through pipelines, the outlets of the plate heat exchangers are respectively communicated with the inlet of the second non-condensed gas preheater (45) through pipelines, the water inlets of the plate heat exchangers are respectively communicated with the water outlet of the condensate water pump (46) through pipelines, the water outlets of the plate heat exchangers are all communicated with a water outlet pipeline, the outlet of the second non-condensed gas preheater (45) is communicated with the inlet of the first non-condensed gas preheater (44) through a pipeline, the outlet of the first non-condensed gas preheater (44) is communicated with the inlet pipeline (16), the gas inlet of the first non-condensed gas preheater (44) is communicated with the non-condensed gas outlet of the evaporation device, the gas outlet of the first non-condensed gas preheater (44) is communicated with the gas inlet of the second non-condensed gas preheater (45), and the gas outlet of the second non-condensed gas preheater (45) is communicated with the gas inlet of the surface condenser (3).

7. The wheat starch process wastewater MVR evaporation system of claim 1, wherein: The material tank (1) comprises two parallelly arranged wastewater buffer tanks, the outlets of the two wastewater buffer tanks are respectively communicated with the inlet of the conveying pump (2) through pipelines, and the wastewater buffer tanks are provided with stirring devices.

8. The wheat starch process wastewater MVR evaporation system of claim 1, wherein: The discharge pipeline comprises a discharge main pipe (19), a thick slurry discharge pipe (20), a cleaning discharge pipe (21) and a backflow pipe (22), the discharge port of the discharge pump (11) is communicated with the thick slurry discharge pipe (20), the cleaning discharge pipe (21) and the backflow pipe (22) through the discharge main pipe (19), the thick slurry discharge pipe (20) is communicated with the finished product tank (23), the cleaning discharge pipe (21) is communicated with the sewage tank (24), and the backflow pipe is communicated with the material tank (1); the discharge main pipe (19) is provided with a mass density meter (25), the thick slurry discharge pipe (20) is provided with a thick slurry discharge valve (26), the cleaning discharge pipe (21) is provided with a cleaning water discharge valve (27), the backflow pipe (22) is provided with a backflow valve (28), the thick slurry discharge valve (26), the cleaning water discharge valve (27) and the backflow valve (28) are controlled through the mass density meter (25), the thick slurry discharge pipe (20) is provided with a flow sensor (29), the discharge main pipe (19) is provided with a total discharge valve (30), and the total discharge valve (30) is controlled through the flow sensor (29).

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