In the temperature range of 500–2500°F, nonequilibrium flow analysis predicted only a small change in pyrolysis gas composition as the gases flow through the char zone. Essentially all of the reactions took place in the temperature range of 2000–2500°F. Comparing nonequilibrium flow with the two limiting cases, the energy absorbed in the char zone for frozen flow was two-thirds that of nonequilibrium flow, and equilibrium flow was about four times that of nonequilibrium flow at the 2500°F level.