Tiivistämisvaihe

Tiivistämisvaihe, commonly translated as the concentration or condensation phase, is a stage in many industrial and laboratory processes in which a mixture is concentrated by removing a portion of the solvent. The objective is to increase the concentration of dissolved substances and to reduce the volume to facilitate subsequent operations such as crystallization, drying, or separation. The phase typically follows initial processing steps and precedes final product recovery or discharge.

Common methods used in tiivistämisvaihe include thermal evaporation (single- or multi-effect evaporators, sometimes under reduced pressure), membrane concentration (reverse osmosis, nanofiltration or ultrafiltration), and, in some cases, freezing or crystallization-based concentration. The choice depends on solvent properties, sensitivity of solutes, energy costs, and required purity. In many cases energy integration, such as heat recovery, is important.

Key design and control considerations include temperature and pressure control, solubility limits, fouling of membranes, solvent handling safety, and environmental impact. Tiivistämisvaihe is used across industries, including chemical manufacturing, food and beverage processing, pharmaceuticals, and wastewater treatment, where solvent recovery or volume reduction is economically or environmentally advantageous. The term can also appear in process development and project planning to denote the phase where concentrate streams are produced before downstream purification or disposal.