# Environmental Impact of the Natural Gas Liquefaction Process: An Example from China
## 4 Conclusions  
This article uses the LCA method to study the problem of industrial pollutant emissions during the natural gas liquefaction process in China. The production data were collected for 86 LNG liquefaction plants in China and the gas quality reports were collected for eight major natural gas liquefaction production provinces (Xinjiang, Inner Mongolia, Shanxi, Shanxi, Ningxia, Henan, Sichuan, and Hebei). Using a natural gas liquefaction plant in Shanxi Province as the process flow reference, we performed a series of data processing and calculations. We first conducted a quantitative study on the environmental impact of natural gas liquefaction. Specifically, the environmental impact potential of natural gas liquefaction at the unit output level of the listed eight provinces, and the environmental impact potential of natural gas liquefaction at the annual output level, were calculated and compared. Based on this, China's GWP, AP, EP, POCP, DP, and total EI potential were calculated, and the following research conclusions were drawn. First, 93.60% of China's natural gas liquefaction output was concentrated in eight provinces: Xinjiang, Inner Mongolia, Shanxi, Shanxi, Ningxia, Henan, Sichuan, and Hebei. Among them, Inner Mongolia and Shaanxi had the largest number of liquefaction plants, and the sum of LNG production in the two provinces exceeded 50% of the total national output. The reason for this may be attributed to the relatively low construction cost of the LNG liquefaction plant in Inner Mongolia, the small initial investment, and local policies that are conducive to the construction of these plants. Shaanxi Province had a large amount of natural gas extraction. Building a liquefaction plant nearby may reduce transportation and time costs. Second, in terms of the unit LNG production, the GWP, AP, EP, POCP, and DP of each province explained the gas composition of LNG production gas sources in each province. Among them, Inner Mongolia, Ningxia, and Shaanxi contained the largest greenhouse gas emissions, and Sichuan had the lowest greenhouse gas emissions. Gas sources in Xinjiang, Hebei, and Henan contained the greatest amount of acidified substances, and the remaining five provinces had low amounts. Xinjiang, Hebei, and Henan collectively had the most gas eutrophication in the gas source, and the remaining five provinces had low amounts of gas eutrophication. Shaanxi, Ningxia, and Inner Mongolia had the highest levels of photochemical smog, whereas Sichuan had the lowest levels of photochemical smog, Gas sources in Sichuan, Shaanxi, and Inner Mongolia contained the greatest amount of dust, whereas Shanxi had the least amount of dust. Third, in terms of annual LNG production, the GWP, AP, EP, POCP, DP, and total EI potential in Xinjiang, Inner Mongolia, Shanxi, Shanxi, Ningxia, Henan, Sichuan, Hebei, and China indicated different environmental issues in various provinces and in China overall. Specifically, in terms of greenhouse gas emissions, Inner Mongolia and Shaanxi had the largest emissions, and the resulting greenhouse effect may be the most severe. In terms of acidifying substance emissions, Hebei and Xinjiang had the greatest emissions and may, therefore, experience the greatest acidification effect. In terms of eutrophication emissions, Xinjiang, Hebei, and Inner Mongolia had the greatest emissions, and the eutrophication effect of the water bodies was a major concern. In terms of photochemical smog emissions, Inner Mongolia and Shaanxi had the greatest emissions, and the resulting photochemical pollution effects were the most evident concerns. In terms of dust emissions, Inner Mongolia and Shaanxi had the greatest emissions, and the dust pollution effect was the most severe. It was evident from the total environmental impact potential that Inner Mongolia and Shaanxi were the most affected by severe environmental pollution during the natural gas liquefaction process. Based on the above research conclusions, this article makes the following three suggestions.