Normal temperature vacuum evaporator is widely used in many industrial fields, but it shows obvious differences in applicability when treating solutions of different concentrations.
First, for low-concentration solutions, normal temperature vacuum evaporator has a higher treatment efficiency. Due to the low concentration of the solution, its boiling point is relatively low, and it can evaporate more quickly in a vacuum environment. For example, when treating some low-concentration chemical wastewater, the normal temperature vacuum evaporator can quickly evaporate the water, so that the solute in the solution can be concentrated and recovered. In addition, the viscosity of low-concentration solutions is usually small, and the flow resistance in the evaporator is not large, so it can circulate smoothly in the pipeline and evaporation chamber, which is conducive to the uniform transfer of heat and the continuous evaporation process, reducing the risk of scaling and blockage, and the maintenance cycle of the equipment is relatively long.
Secondly, the treatment of medium-concentration solutions poses certain challenges to normal temperature vacuum evaporator. As the concentration of the solution increases, its boiling point rises, and the energy required for evaporation increases, which may lead to a decrease in evaporation efficiency. At the same time, the viscosity of the solution begins to increase, the fluidity in the evaporator becomes poor, and local overheating and scaling are prone to occur. For example, when processing certain medium-concentration food concentrates, it is necessary to more finely control the evaporation temperature and vacuum degree to prevent the destruction of nutrients due to local overheating and the influence of scaling on the heat transfer performance of the equipment. In addition, medium-concentration solutions may produce foam during the evaporation process, which requires the evaporator to have an effective defoaming device, otherwise it may cause the solution to overflow or affect the evaporation effect.
Furthermore, the processing of high-concentration solutions is a difficulty faced by normal temperature vacuum evaporators. The boiling point of high-concentration solutions is greatly increased, and the evaporation process becomes extremely slow, requiring a lot of energy. Its high viscosity characteristics make the flow of the solution in the evaporator almost stagnant, which is very likely to cause pipe blockage and uneven heat transfer. For example, when processing high-concentration salt solutions, the solute may quickly crystallize and precipitate on the heating surface of the evaporator to form a hard scale layer, which not only reduces the heat transfer efficiency, but also may damage the equipment. Therefore, for high-concentration solutions, it is often necessary to specially design and modify the normal temperature vacuum evaporator, such as adding a stirring device to promote the flow of the solution, using a special anti-scaling coating, or regularly performing chemical cleaning to ensure its normal operation.
Finally, in practical applications, in order to improve the applicability of normal temperature vacuum evaporator in the treatment of solutions of different concentrations, segmented evaporation or a combination of other treatment technologies can be used. For medium and high concentration solutions, pretreatment can be performed to reduce the concentration, or parameters such as vacuum degree and temperature can be adjusted in time during the evaporation process to adapt to changes in solution concentration. At the same time, combined with advanced automatic control systems, it can monitor solution concentration, temperature, flow rate and other parameters in real time, and automatically optimize the evaporation process according to the characteristics of solutions of different concentrations, thereby maximizing the effectiveness of normal temperature vacuum evaporator in the treatment of solutions of various concentrations, reducing operating costs and improving production efficiency.
