Particulates separation technologies for syngas purification

Particulate separation is a crucial issue to make syngas exploitable downstream the gasification units, in devices for thermal and power production, synthesis of fuels and chemical commodities. This chapter illustrates the definition, classification, formation, and composition of the particulate matter, reports the main limits tolerated by the typical components that utilize syngas versus the quantity normally present in the syngas, and describes the main devices used for removing particulate from the gas stream. The technologies used for the removal of particulate are divided based on the working temperature of the cleanup devices: low, mid-high, and high temperature. The methods up to 250°C, as bag and sand filters, electrostatic precipitators, and scrubbers are mature and efficient techniques but generate waste and suffer from energy inefficiencies requiring to cool and reheat the gas stream in hot gas applications such as a gas turbine, high-temperature fuel cells, and hot chemical processes. The methods up to 900–1000°C, such as cyclones and metallic and ceramic filters, do not require to cool and reheat the gas but, owing to the operation at high temperature in extreme environments are, for the majority, still under development. This is the reason why, in this chapter, more focus is done on the new high-temperature methods.