The political and economic background to the development of coal-based substitute natural gas processes will be familiar to readers and, therefore, need not be detailed herein. The technical problem can be regarded very simply as having two parts, namely the gasification of coal followed by conversion of the product gas into SNG. Proven commercial processes, eg. Koppers-Totzek, Lurgi, etc exist for coal gasification and several second generation processes are in various stages if development in the United States and elsewhere. The composition of gases produced by these processes differ depending upon operating conditions ie pressure, temperature, steam addition, etc.

Methanation for SNG production is complex because the high concentrations of CO and CO2 involved result in large potential temperature increases. This may cause sintering of the catalyst or for some cases a potential for carbon formation. One solution is to include a recycle stream of product gas as a diluent. It is evident that this solution involves a loss of energy in the recycle operation, and that an economic process should allow minimum recycle. For an adiabatic process, however, this is equivalent to a large temperature increase.

The coupling transformation of n-hexane and methanol over HZSM-5 has been investigated with a pulse-reaction system. In the temperature range of 400–500℃, kinetic data was collected and reaction order was determined. Compared with the pure n-hexane cracking, the increased rate constant and the lowered apparent activation energy clearly demonstrate an improvement of n-hexane activation using methanol as co-reactant and an increased contribution of faster bimolecular mechanism to the n-hexane transformation due to methanol introduction.

In recent years, fuel market and environmental policies have reinforced the key role of hydrogen, increasing dramatically the demand and the research on its application in fuel-cell systems. Hydrogen is not an energy source, but an energy carrier, therefore, it must be produced: currently, the stream reforming of hydrocarbons is the largest and most economical way to produce H2.