一、前言中国有丰富的能源资源，但结构不尽合理，仅煤炭就占百分之七十以上，而石油和天然气资源相对不足。根据中国的能源政策，在相当长时期内，以煤炭为主要一次能源的状况不会发生大的变化。由于中国缺少天然气和液化石油气，致使除少数大城市外，多数中小型城市的工矿企 I. Foreword China has abundant energy resources but its structure is not reasonable. Coal alone accounts for more than 70%, while oil and natural gas resources are relatively scarce. According to China’s energy policy, there will be no major change in the status of coal as a primary energy source for a relatively long period of time. Due to the lack of natural gas and liquefied petroleum gas in China, with the exception of a few big cities, most industrial and mining enterprises in small and medium-sized cities