Coalescing system for removing potassium hydroxide in an alkoxylation plant

Identifier:  TFG:2229

Handle: https://hdl.handle.net/20.500.11797/TFG2229

Authors:  Kassemy, Redouane

Abstract:
The DOW Chemical Ibérica S.L. polyol plant is about a reaction unit of raw material and the separation section of the desired product. In this project the only objective is the separation unit. The raw product generated in the reactor is stored in a buffer vessel with a recirculation in order to maintain the temperature constant at 130ºC with a shell and tubes heat exchanger, to later introduce demineralized water to the system to dilute the remaining catalyser (KOH). The whole components go through a mixer to ensure that all the potassium hydroxide is diluted totally in the water and following is introduced to the vessel containing the two coalescers, where the final product and waste separation takes place. To improve the separation efficiency of the polyol and also increase the global process performance, a vessel containing two coalescers has been designed, allowing to separate almost the totality of the light phase from the heavy phase. The installed coalescers are of the “mesh” type. This improvement allows to produce 154,400 tonnes/year of the final product, taking into account that the plant produces the 95% hours of the year, with a 99.8% of purity, increasing the quality product and its selling price. With an initial investment of 2.53 MM€ is achieved a net profit of 4.43 MM€/years starting from the fourth year. The global VNA is 12.9 MM.