Widely used Thermal steam recompression evaporation crystallizer in food industry
Thermal vapor recompression (TVR)
Use valuable energy intelligently & multiply
The thermal vapor recompression builds on the same principle as the mechanical alternative, but uses only a portion of the resulting vapor for heating the system. The compression of the steam for heat recovery takes place in a steam jet pump. This is usually designed for a specific operating point and works on the jet pump principle. The resulting energy savings correspond in many cases in about an additional evaporator stage.
WORKING PRINCIPLE
The Evaporator Falling Film TVR is fed from the wet process area. From the balance tank product is heated to at least boiling temperature of the first calandria, depending on the final product demands. This can be done by plate heat exchangers, tubular heat exchanger and/or direct heaters by use of condensate, excess vapours, steam and/or hot water. After the heating process the product is fed to the first calandria where the product starts to evaporate. The evaporator works according the falling film principle, which means that product and vapour are flowing downwards through the tubes. At the bottom, concentrate falls down and vapour is sucked into the separator, whereby the smaller concentrate droplets are separated from the vapour. Concentrated product is pumped to the next pass, whereby the product is further concetrated. After the final calandria pass product is pumped, depending on the product and required concetrate properties, to a next calandria, concentrate tanks of the dryer or via a flash cooler to crystallisation tanks. As the amount of water evaporation is limited and the required temperature difference is relatively high, steam is used as driving force. This is referred to as thermal vapour recompression (TVR). Depending on capacity and specific product needs the number of stages and thermo-compressors are defined. A density controller in the concentrate flow is used to set the steam flow to the thermo-compressor.
Features of thermal vapor recompression evaporation crystallizer:
1. In the process of thermal vapor recompression, the steam in the boiling chamber is recompressed to a higher pressure in the heating chamber according to the heat pump principle.
2. The saturated steam temperature corresponding to this heating steam pressure is high
Thermal vapor recompression evaporation crystallizer parameters:
Evaporation(t/h) 0.5-4
Raw steam consumption(t/h) 0.2x evaporation/three-effect meter
Raw steam pressure(MPa) 0.2-0.4
Steam energy consumption ratio(t/t) 0.02
Electric power(Kw) (28-62)x evaporation
Compressor provides temperature range 10-40℃
Evaporation temperature range 40-80℃
| Performance Comparison for Different Evaporator | ||||
| Item | Single effect evaporator | multi-effect evaporator | TVR evaporator | MVR evaporator |
| Energy consumption | energy consumption is much higher than others, 1ton water will consume 1Ton steam in theory | comparatively energy conservation | Base on traditional multi-effect evaporator, one more effect added, but higher pressure steam driven needed | The most energy saving technology for evaporator, but 10-40kwh power consumption |
| Floor space | Small | large | large | small |
| Energy sources | steam & power, need steam pipe network and boiler | steam & power, need steam pipe network and boiler | steam & power, need steam pipe network and boiler, need high pressure steam. | electricity, don't need pipe network, all the close-loop circulation system |
| Automaticity | Semi automatic | Full automatic operation, continuous evaporation | Full automatic operation, continuous evaporation | Full automatic operation, continuous evaporation |
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