Development and testing of tube type wet ESP for the removal of particulate matter and tar from producer gas

This paper reports the development and testing of a state-of-the-art tube type wet electro-static precipitator (ESP) for cleaning producer gas generated through the process of biomass gasification. A wet ESP facilitates the removal of fine particulate matter (less than 1 micron) and tar with the added advantage of low internal power consumption. A tube type wet ESP was designed from first principles and simulations were carried out to prove its performance. Later on a full-fledged wet ESP was designed to process 100 Nm3/hr of gas, and was tested with an existing open top down draft biomass gasification system. Maximum particulate matter removal efficiency of 83% and tar removal efficiency of 62% was achieved. The results were encouraging to the tune that the particulate matter and tar levels were found below the permissible limits (50 mg/Nm3) for naturally aspirated reciprocating engines and thus the proof of concept was established. Nevertheless, the performance fell short of the permissible limits for turbo-charged reciprocating engines. The cause of the same has been identified and further development work is in progress.