GB468405A - Improvements in the carbonisation of coal and the like carbonaceous material - Google Patents

Abstract

468,405. Coking processes. GRIGGS, A. R. March 25, 1936, No. 8931. [Class 55 (i)] In the carbonization of coal or the like by the circulation therethrough of hot combustion products, and wherein the sensible heat in a carbonized part of the charge is transferred to and used to carbonize another part, gas of high calorific value evolved when combustion is reduced or arrested is taken off and stored separately from the gas of low calorific value containing a high proportion of combustion products. A combustion chamber 2 with air supply 3 is arranged above a retort 1 operated by downward distillation, the combustion products being drawn downwardly by a pump 4 and pipe 5, the cooled mixed distillation gas and combustion products being returned by a pipe 6 to the top of the retort, and surplus gas being bled off through a valve 7. After sufficient heat is stored in the upper part of the carbonized charge, the air supply at 3 is shut off, and valve 8 opened admitting gas to purge the charge of poor gases, valve 9 being closed and the gases evacuated through valve 7. Valve 9 is then opened, and valve 7 closed and gas circulation takes place down the retort the heat from the upper part being transferred to the lower part, and surplus gas being bled off through valve 8. In a modification, an external combustion chamber filled with checker bricks is used, and the gases passed upwardly through the retort, an increased supply of heat being obtained from the combustion chamber. Steam may be added to the circulated gases before they pass through the charge, either as they enter the combustion chamber, or the retort, so that the calorific value of the gases is reduced by the addition of water gas or by decomposition of the hydrocarbon gases. Specification 469,607 is referred to.