Royal Society of Chemistry

Table 10

Summary of the contaminants and problems for the gasification process

Unwanted contaminant	Presence	Problems
Tar	A complex mixture of condensable hydrocarbons.	The formation of tar causes major operational and maintenance process problems, including tar blockages of pipework, plugging and corrosion in downstream fuel lines, filters, engine nozzles and turbines.
Particulates	Produced from ash and char bed materials if used for the fluidised bed reactor.	Causes blockage of downstream equipment, such as deposition on SOFC anodes, resulting in blocking of gas diffusion paths.
H₂S, SO_x and HCl	Derived from sulfur and chlorine in the original raw materials.	Causes corrosion of equipment.
Alkali metals	Derived from original raw samples.	Causes problems such as fouling, slagging and corrosion of components in the subsequent systems.

Unwanted contaminant	Presence	Problems
Tar	A complex mixture of condensable hydrocarbons.	The formation of tar causes major operational and maintenance process problems, including tar blockages of pipework, plugging and corrosion in downstream fuel lines, filters, engine nozzles and turbines.
Particulates	Produced from ash and char bed materials if used for the fluidised bed reactor.	Causes blockage of downstream equipment, such as deposition on SOFC anodes, resulting in blocking of gas diffusion paths.
H₂S, SO_x and HCl	Derived from sulfur and chlorine in the original raw materials.	Causes corrosion of equipment.
Alkali metals	Derived from original raw samples.	Causes problems such as fouling, slagging and corrosion of components in the subsequent systems.