Multiple-effect evaporation problem
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I saw some claims that multi-effect evaporation does not increase production capacity compared to single-effect evaporation. How should this be understood? Has the capacity really not increased? What are the characteristics of parallel and counterflow multi-effect evaporation? When should parallel flow be used and when should counterflow be used? I saw on site that the three-effect evaporation equipment became larger step by step – what is the principle behind this? Please give some advice!
The main difference between single-effect and multi-effect evaporation lies in energy consumption! Multiple energy-saving effects! There are co-current, counter-current, and cross-flow types in multi-effect systems. Each one has its own characteristics; if you really want to know more, you can look it up online!
MTO-grade methanol uses multi-effect evaporation
Multi-effect evaporation is outdated; use MVR for new projects to save energy
It depends on both the price of steam and electricity; there’s no one-size-fits-all answer
MVR can only be used for materials with a boiling point elevation of less than 15 degrees
It seems that MVR is being promoted everywhere these days
MVR is being promoted more these days; it seems to have a wider range of applications
It mainly depends on the properties of the material, such as viscosity and the relationship between scaling degree and concentration. As evaporation proceeds, the concentration of the material increases, and accordingly, its viscosity and degree of scaling also increase. Under normal circumstances, flowing with the current is preferred, as it is more energy-efficient due to the phenomenon of self-vaporization. 1. If the viscosity increases too rapidly, resulting in a significant decrease in the efficiency of heat exchange, then a counter-current flow pattern should be considered; in a counter-current setup, the increase in concentration corresponds to high-temperature steam, and at such high temperatures, the viscosity decreases to some extent ； 2. If the degree of scaling increases too rapidly, resulting in a significant drop in the heat transfer efficiency, then a co-current flow pattern should be considered; in this configuration, the increased concentration corresponds to steam at lower temperatures, and the lower temperature helps to reduce the degree of scaling. 3. If both viscosity and scale buildup increase too rapidly, a counter-current process can also be considered as an option, since severe scaling can be addressed through regular acid cleaning.