Paisarn Khongphasarnkaln. Removal of trimethylamine acetaldehyde and ammonia gases using electron attachment reaction. Master's Degree(Chemical Engineering). Chulalongkorn University. Center of Academic Resources. : Chulalongkorn University, 1998.
Removal of trimethylamine acetaldehyde and ammonia gases using electron attachment reaction
Abstract:
Experimental investigation on the application of electron attachment to the removal of dilute gaseous pollutants has been carried out using a corona-discharge deposition-type reactor. The high selectivity of electron attachment to electronegative gas molecules is utilized to effectively remove the impurity gases at ppm and even ppb concentration levels. The effects of several factors, namely, discharge current, inlet gas concentration, space velocity and coexisting O2 or H2O vapor on the individual removal efficiency of three kinds of gaseous pollutants, namely, trimethylamine ((CH3)3N), acetaldehyde (CH3CHO) and ammonia (NH3) have been investigated. The experimental results reveal that generally the higher the discharge current, the higher the removal efficiency, whereas the space velocity and inlet gas concentration yield the opposite effects. It has been found that the presence of O2 enhances the removal efficiency of each impurity gas. The enhancement is experimentally shown to be attributable to the ozone reaction in the removal of (CH3)3N from O2-N2 mixed gas. Water vapor also enhances the removal efficienct of (CH3)3N and CH3CHO. Furthermore, the high selectivity of electron attachment to electronegative gas molecules is utilized to the simultaneous removal of dilute (CH3)3N-CH3CHO, NH3-CH3CHO, SO2-(CH3)3N, SO2-CH3CHO, NO2-CH3CHO and CO2-CH3CHO from air in the single reactor in order to find out the effect of discharge current on their removal efficiency. Since undesirable reaction by-products are produced on the removal of SO2-(CH3)3N from air, a two-reactor system has been proposed and shown to remove the binary pair with negligible reaction by-product. The experimental results show that generally the higher the discharge current, the higher the removal efficiency. Compared to single impurity removal, it has been shown that the presence of SO2 enhances the removal efficiency but retards that of CH3CHO in a single reactor, but some reaction by-products are generated. The problem can be avoided by using two independently operated reactors in series. In the case of coexisting of NO2, it is noted that the lower the inlet NO2 concentration, the lower the discharge current that still yields beneficial effect. At higher discharge currents, the retarding effect of CO2 on CH3CHO removal is obviously significant.