Black Liquor Enrichment with Petroleum Coke

摘要

Kraft paper mill energy costs may be significantly reduced by co-firing petroleum coke with black liquor,provided that the mill's recovery boiler has excess firing capacity and steam generation capability.Petroleum coke,a byproduct of petroleum refining with a relatively low cost per unit of energy,may be well suited for use in a kraft mill because it is more than 85% carbon with its major other element being sulfur.A number of recovery boiler technical issues were identified that were addressed in a recently completed laboratory study.Included are:good mixture uniformity and acceptable viscosity to enable conventional liquor spraying methods;minimal change in liquor swelling properties and combustion characteristics to maintain the proper balance between in-flight combustion and char bed reaction phenomena;acceptable disposition of sulfur;and purge of non-process elements via the green liquor dregs.Answers to these questions have been obtained in laboratory study mentioned above,conducted at IP ST @ Georgia Tech using its Single Particle Reactor.Results have facilitated commercialization of the technology with a mill trial at a Southern kraft mill.Preliminary results of that trial have been summarized.