Descriptions

In the falling film evaporation system, the material covers the inner wall of the whole heat exchange tube in a fim shapeflows down the heat exchange tube and evaporates at the same time, Even if the evaporation temperature diference islow, it is still possible to obtain higher heat transfer coeficient, The middle part of the heat exchange tube is filled withsecondary steam formed by evaporation of materials, in the desian, the secondary steam and materials can flow in thesame direction or reverse dlirection in the heat exchange tube according to the siluation, Secondary steam leaving theheat exchange tube then enters the separator to complete vapor-liguid separalion, The separator can be conventionacentrifugal or impact type; it can be designed as a separate type independent of the faling film heater, or as anintegrated type integrated with the heater, The integrated design can reduce the floor space and installation costCirculating evaporation is needed to evaporate materials with slight scaling problem; Even if materials are recycled, fallingfilm design is much more energy-saving than forced recycling. Direct faling film design can be adopted for heat-sensitive materials to shorten the residence time of materials and reduce the energy consumption of pumps, Faling fimevaporation system is suitable for treating materials with no scaling problem or low scaling coeficient, and usually cannotbe used for crystallization, However, according to the characteristics of evaporated materials, falling film and forcedcirculation can be combined in the design to treat materials with scaling problems and continuous crystallization systems.In lMvR (Mechanical Steam Compressian) and TVR (Steam Power Heat Pump) design, low evaporation temperaturedifference can reduce power consumplion and sleam consumption, and faling fim desian can be used in the case of lowevaporation temperature diflerence, so it is more suitable for this kind of design, Afected by the characteristics ofmaterials or when low-temperature waste heat is used for evaporation (such as tube bundle tail aas or iouefied flashsteam), the maximum material temperature in the evaporator is limited, Compared with the falling fim design, moreefficiency can be put in to reduce energy consumption, Faling film systems are widely used in food, pharmaceutical.chemical, paper/pulp, and coal chemical industries.

Features

With the characteristics of high heat transfer coefficient, small adaptive temperature difference and high vacuumevaporation, the waste heat evaporation unit composed of low-quality waste heat (such as dryer hot air and flue gasand waste heat (condensed water, process water and its flash steam) can complete the concentration task with litleor no fresh steam, thus realizina the breakthrough of "zero" raw steam for evaporation, it has the advantages of highheat transfer efficiency, small temperature diference, no boling point loss caused by liquid column and less powelconsumption.

Technological Process