Question

1.In combustion of natural gas how is the water influence the reaction(as quantity and quality)? List assumptions and conditions.

2.What happens to concentration of CO as a function of time in combustion of natural gas (as quantity and quality) ? List assumptions and conditions. (Constant Volume, Isothermal, Batch Reactor, Ambient air O2. )

Answer 1

1. Water vapour present in the natural gas composition can result in hydrate formation and further complications of blockage in fuel gas lined due to pressure reduction at various stages before entering into combustion chamber. Hence the natural gas composition shall have limitations on water vapour content. The basic control parameter of water vapour is based on hydrate dew point temperature i.e. the dew point of natural gas shall be 11 deg c less than the gas temperature at operating pressure of natural gas fuel system.

2. The complete combustion of natural gas results in carbon dioxide and water. The complete combustion mechanism requires oxygen from amhieam air in required quantity.

If our assumption is combustion in a closed chamber where enough air circulation is not possible, then the combustion reaction will turn to incomplete combustion and will produce carbon monoxide, free carbon and water. Hence the combustion reaction results in release of carbon monoxide over a period of time. The rate of carbon monoxide release will increase with respect to the decrease in the oxygen supply rate into the combustion chamber.