Plant experience in qualifying raw materials for the carbon plant

摘要

With new environmental regulations,changing product demands and changing business climates,the sources of feed stocks to the coke calcining and pitch processing facilities are frequently changing in quality and quantity.The challenge for Carbon Plants is to produce a consistently high quality product while facing changes in the incoming raw material streams.The influene of changes in the raw materials may not occur immediately but will be seen,as butt return is recycled from the Potrooms.Changes that may occur could be seen in net carbon,return butt weight,pitch demand,and aggregate sizing among other factors.This paper outlines Century's experience in the effect of recycle butt materials on carbon performance and the number of anode cycles it may take to totally add or remove the influence of a raw material from the carbon product.This paper also includes details on the procedures used to qualify new or changed raw materials in the ravenswood Operation's Reduction Plant.These procedures take into account the effect of recycle butt material in plant and Laboratory scale testing.Practical examples are given of recent plant and Laboratory scale testing of a coal tar/ petroleum pitch versus a coal tar pitch used in anode production.