Study of hygroscopic media for recovery of waste heat from flue gases in hygroscopic condenser/absorption column

Chaudhry Haider Ali, Mats Westermark, Muhammad Zafar, Tanveer Iqbal, Saima Yasin, Haris Mahmood Khan


The hygroscopic medium is utilized in the hygroscopic condenser to recover waste latent heat from the flue gas carrying useful moisture. Potassium formate has shown very good performance as hygroscopic medium. Apart from potassium formate the search for various salts that could be utilized as hygroscopic media has been carried out. In this study the main focus is on the solubility of the salt, the boiling point of the solution and the effect of the by-products. Potassium formate being utilized practically and showing various advantages over other salts is analyzed in the laboratory. The sulphates are likely to cause precipitation within the solution. The precipitation affects the performance of the hygroscopic condenser. The flue gas exiting the hygroscopic condenser has still some useful energy. The reduction in dew point of vapors exiting the condenser from 40 °C to 30 °C will increase the recovered heat from 657 kW to 795 kW in hygroscopic condenser operating with a gas engine with a capacity of 2000 kW that is utilized in Bauska, Latvia. This heat recovery could be achieved by utilizing high boiling hygroscopic solution and with better heat and mass transfer in the condenser.

Full Text: JPIChE 45 (1) 2017 113-119

Published by Pakistan Institute of Chemical Engineers (PIChE)

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