Working principle
Secondary steam cascade utilization: The dual effect
evaporator is composed of two evaporators connected in series. The first evaporator (first effect) uses external fresh steam (raw steam) to heat the wastewater, causing it to boil and produce steam, namely primary steam (also known as secondary steam). These secondary vapors then enter the second evaporator (second effect) as a heat source to heat the wastewater entering the second effect, achieving further evaporation of the wastewater and fully utilizing thermal energy to improve evaporation efficiency.
Pressure and temperature control: The first effect usually operates at normal or slightly positive pressure, with a relatively high temperature, usually around 100 ℃; The second effect is at low pressure (vacuum environment), maintained by a vacuum pump to lower the boiling point of the solution, for example, from 100 ℃ to 60-70 ℃. This allows for further evaporation of water at lower temperatures and also helps to reduce the impact on heat sensitive materials.
FEATURES
Efficient and energy-saving: By connecting two evaporators in series, the steam generated by the first effect is fully utilized as the heat source for the second effect, improving the efficiency of heat utilization and reducing energy consumption. The theoretical steam consumption is only 50% of that of a single effect, and only 0.5kg of steam is needed to evaporate 1kg of water.
Environmental protection and emission reduction: It can effectively treat wastewater, reduce wastewater discharge, and lower environmental pollution. At the same time, valuable resources such as salt and organic matter in wastewater can be recycled to achieve resource reuse and reduce resource waste.
Strong adaptability: Suitable for treating wastewater of different compositions and concentrations. By adjusting operating parameters and equipment structure, it can adapt to wastewater treatment tasks of different scales and needs.
Stable operation: Advanced control system is adopted to achieve automated operation and precise control, ensuring the stability and reliability of equipment operation.
Strong anti scaling ability: Compared with the multi effect evaporator, the material residence time in the double effect evaporator is shorter. When dealing with some easily scaling materials, the possibility of scaling is relatively small, and the anti scaling ability is stronger.
Equipment Structure
Heating chamber: Generally, a tube or plate heat exchanger is used, where steam condenses and releases heat outside the tube, and the solution absorbs heat and evaporates inside the tube.
Separation chamber: used for gas-liquid separation to prevent liquid droplets from entering the next effect with steam, ensuring the purity of steam and the normal operation of the next effect evaporator.
Vacuum system: mainly used to maintain a low-pressure environment for the second effect, reduce the boiling point of the solution, and enable the solution to evaporate at lower temperatures. It is usually composed of equipment such as vacuum pumps.
Condenser: used to condense the secondary steam of the final effect, turn it into liquid water and discharge it, maintain the vacuum degree of the system, and also recover the heat released during the condensation process.
Application Area
Food industry: used for concentrating fruit juice, dairy products, sugar solutions, sauces, etc., removing excess water and increasing material concentration while ensuring that food flavor and nutritional components are not destroyed.
Pharmaceutical industry: It can be used for the concentration treatment of drug solutions, especially for the concentration of thermosensitive biopharmaceutical products. Low temperature operating environment can effectively retain the active ingredients and efficacy of drugs.
In the field of chemical engineering, it is suitable for the concentration and purification of various chemical solutions, such as acid-base solutions, chemical raw materials, intermediates, and dye solutions. It can also treat chemical wastewater, recover useful substances from wastewater, reduce treatment costs, and minimize environmental pollution.
Metal mining: used in the smelting process of metal mining to evaporate and crystallize solutions containing metal ions, achieving the extraction and purification of metals.
Power industry: It can treat the wet desulfurization waste liquid from power plants, recycle and reuse the salt and other substances in it, and reduce the impact of wastewater discharge on the environment.