Evaluation of amine emissions from the post-combustion CO2 capture pilot plant

Abstract

In this work, we evaluated amine emissions from 10ton-CO2/day scale pilot plant in Mikawa Power Plant of Sigma Power Co. Ltd. within TS-1 solvent. Firstly, we investigated that how sampling gas flow rate affects measured value of amine concentration in flue gas by using on-line sampling method with PTR-MS analyzer. It was found that the error from an iso-kinetic sampling rises sharply for lower sampling velocities and in the range of higher sample stream velocities, however the error is lower. Secondly, we compared between beginning of operation and 2,800hours operation in terms of amine emissions at Mikawa pilot plant under one set of conditions. At beginning of operation, there were no degraded amines in TS-1 solution. Thus, there were no amine emissions of degraded amines. However, at 2,800hours operating, in addition to TS-1 emissions, some quantity of emissions of degraded amines were detected even though degraded amines were much less than TS-1 main amine in TS-1 solution. Toshiba improved operating conditions such as plant system, water wash system to reduce the amount of amine emissions. As a result, the latest tests showed lower emissions of less than 1 ppm(v/v) at 2,800hours operation. A concentration of degraded amine [D] in TS-1 solution at 2,800hours operation, which was nearly detection limit, was lower than other degraded amines. Nevertheless, degraded amine [D] accounted for the greater part of amine emissions after water wash was improved. This result suggested that it is crucial to reduce the volatility of emitted degraded amines in order to improve performance of suppression amine emissions further. Then, finally we evaluated effect of addition acid to reduce the volatility of degraded amine [D]. The results in diluted aqueous amines at 40°C showed that effectiveness of acid for reducing amine volatility is in the order: sulfuric acid > oxalic acid carbonic acid produced by 10%CO2 > boric acid.