"The production of large quantities of low - BTU gas typical of direct retorting processes is described . Alternative methods to use the gas within the processes depends on whether the process is considered to be a continuous or a batch operation. Continuous processes produce a constant quantity and quality of low BTU gas, so processing is not as difficult. The gas from batch processes however, can vary both in quantity and quality, and is more difficult to use. This paper addresses the use of these gases to make batch processes more efficient. Combustion characteristics and design considerations for burning these gases are also presented."