This project explains about solvents valuation, doing the appropriate calculation to carry through a flash distillation. To carry out this calculation, we have to measure a flash separator. We have realized this calculation from calculate feed temperature. We have calculated the outgoing current, vapour current and liquid current, as well as we have calculated the outgoing compositions, the temperature and the pressure operation. In other hand, we have to measure a heat exchanger, to bring the feed from environment temperature to operation temperature. In this sense, the project is characterized by be an open project, given that there are different ways to investigate. This ways of investigation will give us a good form to realize an economical solvent recovery.