Abstract: Energy network diagram is considered as an effective tool to assess efficiency and detect the weakness of an energy-use process，and further for decision-making in energy management. This paper presents a comparison between a domestic SNG project and the US Plain project via energy balance based energy network diagram，including purchase and storage，processing and conversion，input distribution and end-use. The total energy conversion efficiency of the Plain project and the domestic project are 53.16% and 48.20% respectively，which mainly reflects low energy conversion efficiency in the end-use process，so the further step is to resolve the energy bottleneck and improve the level of energy utilization in this process.

Key words: energy network diagram, US Plain project, energy conversion efficiency, energy bottleneck

摘要： 能源网络图作为能源统计数据分析的有效工具和方法，是评价企业用能效率、发掘能耗薄弱环节、科学制定能源管理政策的重要手段。本文以国内某煤制合成天然气企业为研究对象，并以美国大平原项目为参照，基于能量平衡建立能源网络图对两者能量转化的4个重要环节——购入储存、加工转换、输入分配和最终使用的能量转换效率进行详细地对比分析。结果表明，大平原项目能量转换效率为53.16%，而国内该企业能量转换效率为48.20%，主要体现在终端环节中4个系统的用能效率偏低，需进一步挖掘节能瓶颈和改善用能水平。

关键词: 能源网络图, 美国大平原, 能量转换效率, 节能