REDUCING FOULING IN DELAYED COKER HEATERS

摘要

Delayed coking is the most common resid conversion process in the refining industry,with over 635 000 m:Vd(4 million bpd)of worldwide capacity,including bitumen upgraders in Venezuela and Canada.Worldwide delayed coker operating margins have increased significantly since 2003,driven by higher differential values between heavy fuel oils and refined distillates.Delayed coking is an attractive residual upgrading option for refiners seeking high levels of conversion from lower value resids yielded by heavier,higher metals and sulfur content crude oil blends.However,many of these lower value feedstocks have characteristics that can cause accelerated fouling rates in coker heater tubes.High rates of fouling in coker heaters can cause reduced unit run fengths,reduced conversion,and can also limit the refiner's flexibility in selection of crude oils processed.