New candle prototype for hot gas filtration industrial applications

The improvement of gas cleaning technologies is crucial for the establishment of advanced clean power generation coal-based technologies such as Integrated Gasification Combined Cycle (IGCC) or Pressurised Fluidized Bed Combustion (PFBC) which need high performance of the syngas clean-up process. New materials and advanced operating strategies at higher temperatures that could give lower energy penalty are required to be developed. A large scale high temperature filtration pilot plant is available at the ETSI University of Seville. This pilot plant allows testing different filtering elements and pulse cleaning strategies using real coal ash under an extensive range of operating temperature and pressure. The aim of the research is the evaluation of the alternatives for hot gas filtration technologies and the optimisation of the operation and performance of the filtering elements. An experimental campaign was carried out to test a new type of silicon carbide candle. Some prototype candles were fabricated from pyrolysed wood and other materials as result of a novel environment friendly patented process (BioSiC (R)). This process provides good thermo-mechanical, chemical and structural stability in an extensive range of temperatures. Main parameters for the characterisation of the prototype were studied such as filtration velocity, permeability, porosity, pressure drop across the filter, cleaning pulse interval, baseline pressure drop, filtration efficiency and durability of the filter. Optimal operating conditions and pulse cleaning strategies were determined. Additionally, a model to predict the behaviour of the filtering elements under diverse operating conditions was developed. In general, the experimental results showed that the prototypes are suitable for industrial applications under the operating conditions, typical of those required for hot gas cleaning of coal combustion and gasification gases, as used in this study. However, the possible improvements in the performance of the elements were identified that should be carried out in the next experimental campaign. This paper describes the main characteristics of the new material developed as well as the major results and conclusions from the analysis. (C) 2012 Elsevier Ltd. All rights reserved.