Hot Gas Filtration Technologies for Particles in Gasification and Combustion Systems

Abstract

Abstract High efficient hot gas particulate filtration is necessary to protect the downstream heat exchanger and gas turbine components from fouling and erosion to meet emission requirements in advanced combustion systems. The development and optimization of these advanced systems have the role to increase energy efficiency in power generation, complying with international commitments concerning more comprehensive, competitive, sustainable, and secure energy strategies. There have been significant improvements in the development of filters since 1980s. However, filtration at high temperature has not been yet reliably proven, especially above 400°C. High process temperatures impose severe limitations on the mechanical durability and corrosion resistance of components in the gas cleaning units. The identification of suitable technologies, from an operational and economic point of view, capable of overcoming current and future limitations in hot gas filtration processes is therefore of the utmost importance in the context of energy efficiency policies and clean technologies. A range of technologies has been proposed for hot gas particulate filtration but few have been developed sufficiently to enable commercial exploitation. Six types of devices (cyclones, ESPs , granular bed, metallic, bag, and rigid filters) are available today, with important differences in capture and rejection mechanisms, pressure drop, flow capacity, and collection efficiency. Special emphasis is made to the development of barrier filter systems which have been supported through an important number of pilot and demonstration projects with considerable contribution from public and national funding bodies. Significant efforts in the development of hot gas filtration technologies have been also made by industry. Ceramic and metallic filters are nowadays the most promising technologies for the application of particulate removal, mainly at PFBC , IGCC , and hybrid power generation systems but also at other applications such as incineration or glass melting factories. However, the need of advanced materials—with higher resistance to fatigue, corrosion, thermal shock, and strength—, higher collection efficiency and proper sealing systems makes crucial the continuation of R&D programs. The development of multipollutants removal devices (particulates in combination with SO x , NO x , or others), the integration of the filter systems into the process, or cost and energy savings are priority areas of interest in the near future.