Multiple-effect evaporator and concentrator
Evaporation plants are well-proven in installations around the world. There are a variety of configurations and models available – from pre-evaporators to multiple-effect evaporation trains – to accommodate even the most challenging pulp mill or effluent plant evaporation needs
The major advantage to multiple-effect evaporators is the utilization of proven lamella heating surfaces for high efficiency and reliability.
pp-evaporation-plant-lamella
Evaporation plant lamellar
lamella heating surface
Critical equipment for the chemical pulp mill
Black liquor evaporation is an essential part of the chemical recovery process as it significantly concentrates the dry solid matter in black liquor so that the liquor can be effectively combusted in recovery boiler. The water removed from the liquor can be segregated and processed so that it can be reused in the mill – reducing fresh water requirements, effluents, and saving money.
Evaporators and concentrators, with their lamella heating surfaces, are adept at processing the spent cooking liquors or mill effluents using the minimum amount of energy while maximizing product dry solids, plant availability, and condensate quality. The lamella heating surfaces are inherently non-scaling. This allows the use of various heat sources inside the lamella, allowing the mill to select the most energy-efficient process connection.
Black liquor evaporation
· Black liquor recovered from pulping contains 14-17% dissolved solids
· These solids are composed of about 1/3 inorganic chemicals that were in the white liquor added to the digester
· The remaining 2/3 consist of the organic chemicals extracted from the wood
· Black liquor must be concentrated to above 60% solids so that it will burn without supplemental fuel
Basic process requirements
· Efficient use of energy
· Efficient separation of water vapor from black liquor
· Proper separation of methanol, tall oil soap
· Concentration of black liquor to 75-85% dry solids
How to reach 80-85% dry solids?
Due to the high viscosity
MP-steam as heating medium
liquor temperature 175 ℃ in final concentrator
Liquor retention time
evaporator acts also as a LHT-reactor
Duplex construction material
high alkali content may cause Stress Corrosion Cracking (SCC)
Best possible energy efficiency
The use of fully integrated foul condensate stripping, optimized liquor distribution, and the ability to use various heat sources within a single thermal effect ensure an evaporation system that meets unique customer requirements while providing the best possible availability and energy efficiency.
| Name | Type series | Shell and tube heat exchanger | Detachable plate heat exchanger | Spiral plate heat exchanger |
| Maximum pressure | <60 bar | <200 bar | <32 bar | <25 bar |
| Heat transfer coefficient to water[W/m2·℃] | 3500 | 2700 | 5600 | 2000 |
| 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 |
Benefits
Energy-efficiency for reduced costs
Highest dry solids liquors with maximum availability using crystallization technology
Cleanest reusable condensates using the minimum amount of steam
Lowest steam and electricity consumption
Self-cleaning
Tolerate even non-soluble scaling
Workshop
Jiangsu Hanpu Mechanical Technology Co., Ltd. is a project engineering company jointly established by Jiangsu Saideli Pharmaceutical Machinery Co., Ltd., Jiangsu Zhongyi Environmental Technology Co., Ltd., FERREO A/S in Denmark, Shanghai Jiaotong University and Nanjing Kingreat Machinery Co., Ltd. Hanpu main projects include but are not limited to: MVR evaporation system, powder washing salt and vacuum salt production project, oil tank sludge cleaning project, landfill leachate treatment project, plant/animal oil processing production line, urban wastewater treatment project, various wastewater treatment projects, and CBD oil extraction production line. Technical support and transfer of API product technology package. The main products are centrifuge series, multi-effect and MVR evaporation and crystallization equipment, laser welding heat transfer board, lithium battery material mixing equipment, pressure vessel and titanium, zirconium, nickel, and other non-standard special equipment.
Tip:Dimple Plate Heat Exchanger ; Black Liquor
