Multiple effect mvr dimple plate evaporator for pulp Black Liquor in paper production field
“Black Liquor” is a by-product of pulp from mills that make products from trees, such as paper. It is currently used to recover cooking chemicals and produce high-pressure steam used in the pulp and paper-making process. It is composed of different ingredients from these processes such as lignin, hemicellulose, sodium hydroxide (NaOH) and sodium sulfide (Na2S). The lignin compound in black liquor can be used to make biofuel but it can be expensive to produce and so fuel made from it is not very common. However, and according to the International Energy Agency (IEA), the future of using black liquor as fuel is promising and it is seen as the fifth most important fuel on earth!
Multiple effect evaporation
It is a system that connects multiple evaporators. Only fresh steam is added to the first effect, and the generated secondary steam is used as the heating steam of latter effet, that is,the heating chamber of the latter effect becomes the condenser of the former seconday steam. By analogy, the last effect is often operated with colling medium. Therefore, multi-effect evaporation not only significantly reduces the consumption of heating steam, but also significantly reduces the consumption of cooling medium.
Main driven power of MVR evaporation system is electric energy. Electric energy transfer to mechanical energy and improve the quality of second steam which is more economic than produce or purchase fresh steam.
Under most of the evaporation process, system no need fresh steam during operation. Only need some steam compensation for pre-heating the raw material when heat energy from product discharged or mother liquid cannot be recycled due to process requirement.
No need independent condenser for second steam condensation, so no need circulating cooling water. Water resource and electric energy will be saved.
Compared with traditional evaporators, MVR evaporator temperature difference is much smaller, can achieve moderate evaporation, greatly improve product quality and reduce fouling.
Evaporation temperature of system can be controlled and very suitable for evaporation an concentration of thermal sensitive product.
Lowest energy consumption and operation cost,electricity consumption of one ton water's evaporation is 2.2ks/C.
|Name||Type series||Shell and tube heat exchanger||Detachable plate heat exchanger||Spiral plate heat exchanger|
|Operating temperature range||<800℃||<800℃||<170℃||<350℃|
|Maximum pressure||<60 bar||<200 bar||<32 bar||<25 bar|
|Heat transfer coefficient to water[W/m2·℃]||3500||2700||5600||2000|
|Application of air and water heat exchange||fit||fit||not fit||Partial fit|
|Immersion in tank or water||fit||Partial fit||not fit||not fit|
|Welding of tank and reactor||Applicable||not applicable||not applicable||not applicable|
|Install into the existing reactor and other equipment||Flexible application||Partial applicable||not applicable||not applicable|
|All welded construction||Applicable||Applicable||not applicable||not applicable|
|Heavily contaminated liquids and other applications||Applicable||Applicable||Partial Applicable||Applicable|
|Weight per unit area||low||high||low||high|
|Falling film, condenser and evaporator||fit||fit||Partial fit||Partial fit|
Falling film evaporator is suitable for cooling a large amount of water or liquid to as low as 0.5 ℃. It has high efficiency heat exchange performance and stable and reliable operation. The falling film heat exchanger adopts the world's leading laser welding, and the heat transfer plates are arranged according to a certain plate spacing to form a plate bundle. One side of the plate bundle with a wide channel goes through one fluid, and the other one goes through the plate inside, so as to achieve the heat transfer effect. The heat transfer plate with wide channel design makes the heat exchanger not only have high heat transfer coefficient, but also have the technical characteristics of high temperature and high pressure resistance, dirt resistance, easy cleaning, suitable for polluted liquid or viscous liquid, which is significantly better than the traditional heat exchanger.
Typical application fields of falling film evaporator
Cold storage of agricultural products, poultry processing, bread processing, food and dairy processing, seafood processing, meat processing, beverage industry, concrete cooling, etc.
Laser welding heat transfer plate
The heat transfer plate is made by automatic laser welding and forming process. Its special pillow structure makes the fluid form the best turbulent state, achieves efficient heat transfer, and has the characteristics of dust resistance, high temperature and high pressure resistance, easy cleaning and so on.