This system is designed by HBC to combine the best technologies from the “old school” of coal combustion and the latest advanced combustion control technologies. The new HBC chain grate-type stoker system permits either bituminous coal washed singles or smalls to be combusted in an efficient manner with the added advantage of automatic de-ashing. This combination is particularly suitable for industrial heating and process steam applications. The boiler vessel is a three-pass fire tube design incorporating a wet back turnaround that eliminates the need for rear door refractory.