Introduction

In most industrialised countries low calorific value gas manufactured principally from coal feedstocks, and distributed generally at low pressures for public consumption and to small industrial consumers for fuel purposes through localised pipeline grids, is either being or has already been displaced by high calorific value, high-pressure natural gas. Undoubtedly the availability of natural gas, with its inherent economic, qualitative, technical and other advantages over manufactured gas, has been the saviour of the gas industry in recent years. It is doubtful whether the traditional manufactured gas industry could have survived, in the face of increasingly severe competition from liquid petroleum fuels and electricity, if it had had to rely upon manufactured gas indefinitely.