Hot gas filters for coal-based power generation systems: Operating experiences

A semi-industrial filtration facility is currently in operation at the ETSI-University of Seville, with financial support from the European Commission and the Spanish Ministry of the Environment. This pilot plant allows testing different elements and reverse-flow pulse cleaning strategies using real coal ash and under diverse operating conditions such as temperature and pressure. The aim of the on-going research is the evaluation of the alternatives for hot gas filtration technologies and the optimisation of the operation and performance of the filtering elements. The first experimental campaign carried out in the filtration facility commenced in 2005. Four types of elements were tested at maximum temperature and pressure of 235 degrees C and 7.5 barg respectively. This paper describes the main results obtained during the second phase of the experimental campaign, in which the temperature was increased up to 370-550 degrees C. Three types of elements (one type of bag filter and two types of candles) were tested. Main parameters investigated for the characterisation of the filtering elements performance were the pressure drop across the element, the cleaning pulse interval, the baseline pressure drop, the filtration efficiency and the durability of the elements. Dependences on the particle loading and temperature among others were also established. Results obtained and conclusions extracted provide a useful tool for the implementation of the filtration technologies at industrial scale. (C) 2011 Elsevier Ltd. All rights reserved.