Due to tar fouling on heating wall, boiler efficiency decreases. To reduce the Tar fouled, I used catalyst (dolomite and lime powder) in-situ, in wood pellet boiler. The results showed that fouled material color changed (whitish material fouled). I think used catalysts also fouled on the heating plate. I am really looking to find out the method which trapped the catalyst in the bed and prevents it from fouling.
The main impurities associated with boiler feed water are silica, sodium, calcium and other metal ions. The catalysts used in boiler to reduce fouling are copper, nickel, platinum, zeolites etc,. Fuel additives to improve combustion efficiency of boiller and to keep gas side heat trnasnfer keep higher by reducing soot are aluminium oxide, ammoniam bycarbonate, magnesium oxide, silica and zinc. Magnesium oxide can minimize the fouling of coat-fired boilers by acting as catalytic inhibitor to retard the formation of SO2 and reacting to MgSO4, whici is inert and high melting point.
Under some circumstances, corrosion inhibitors such as phosphates can be source of fouling in heat exchangers as they increase salt content of water. This can be minimised bycareful control of parameters such as inhibitor concentration, flow velosity, and suface temperature.
Steaming is a recognised procedure for decoking caalysts.
Ref: The impact on catalyst performane due to poisoning and fouling mechanism by G.B. Hawkins
www.gbhenterprises.com/the%20impact%20on%20catalyst%20performanc.
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