The design and implementation of a small endothermic generator for laboratory use

"The design and implementation of a small endothermic generator is described. The required safety features for the generator are discussed. A small endothermic generator was designed to be heated by electric heating elements and utilize propane for the creation of a protective atmosphere for the heat treatment of steel. The comprehensive design calculations included: the equilibrium gas composition of propane at cracking temperatures; the energy required to heat the reaction gases and provide sufficient energy to provide cracking of propane; and shell losses to the refractory. Construction of the generator is detailed Performance comparisons to a mathematical model of a packed bed is described. A parametric analysis of operating variables was performed and the results provided. Results indicated that the best operating performance was obtained with a temperature of 1065°C, an air to propane ratio of 7.6 to 1, and small catalyst size without alumina topping. It was found that the alumina topping contributed to a higher exit temperature of the dissociated propane, but caused a premature sooting reaction at the exit end of the retort"--Abstract, page iii.