E3.1 Adiabatic Flame Temperature

Example 3.1: A producer gas containing 20% CO and 80% N₂ is burned with 100% excess air. Both air and gas enter combustion zone at 1000 °C.

Calculate the theoretical flame temperature. Specific heat constants a, b, and c are given as follows:

Solution: Basis of Calculations: 1 mole of CO entering the combustion chamber.

Number of moles of components:

The feed contains 1 mole of CO, and 4 moles of N₂. Oxygen is derived from air that has 3.76 moles of N₂ for every mole of O₂.

a, b, and c for the feed (Equation 3.2):

a, b, and c for the product (Equation 3.3):

These values have been tabulated.

Integration constant, H_Fo (Equation 3.5):

Enthalpy of the feed at T_F, = 1273.15 °K (Equation 3.4)

Integration constant H_Po (Equation 3.7):

Enthalpy of the products, SH_P (Equation 3.8):

Temperature of the products, T (Equation 3.9):

These values are tabulated for all iterations.

However, if the feed is at 25 °C, then enthalpy of the products can be calculated as 6.764´10⁴ calories and the product temperature is 1216 °K.