FURNACE TUBE DEPOSITS FROM AN INDIAN REFINERY - SPECTROSCOPIC INVESTIGATION OF DEPOSITS AND THEIR PREVENTION

Furnace tube fouling by burning of residual fuel oil (RFO) is widely e ncountered in both process as well as boiler furnaces. Fouling becomes significant when fuel contains sulfur compounds and metallic constitu ents such as V, Na, Ni, Fe etc. Study on one such problem, faced in an Indian refinery has been taken up. In the present study, furnace depo sits collected during shut-down operations of atmospheric distillation unit, have been analysed using XRD, ICAP, XRF and IR techniques. Fact ors responsible for frequent fouling of process furnace tubes were ide ntified. Sodium nickel sulfate formed during combustion process causes primarily the formation of deposits on furnace tube surfaces. For red ucing furnace tube deposit, different types of commercially available additives have been evaluated. Incorporation of calcium based additive s modified the deposit into non-sticky high melting phases.