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To promote the development of gas-powered vehicles in our city, in accordance with the arrangements of the municipal authorities, and with the cooperation of the municipal bus company and FAW Automotive Research Institute, we have carried out extensive experimental research since October 1997 on the selection of liquefied petroleum gas as a fuel source for vehicles as well as on the purification of its quality. When selecting the gas source, taking into account the fact that there are many refining enterprises in Northeast China, particularly in the Daqing area, that liquefied petroleum gas is abundant there at low prices, we have always adhered to the principle of choosing domestic gas – specifically, refinery gas or associated gas from the large oil refineries in the Daqing area, which has a low content of sulfur and butadiene. Over the past two years, we have conducted road test trials on 9 types of liquefied petroleum gas from 7 refineries – including Daqing Petrochemical Complex, the Fine Chemicals Plant, Nanyuan Refinery, Jihua Refinery, Qianguo Refinery, Harbin Refinery, Shuangyang Oil Extraction Plant, as well as those produced by Jihua Refinery – as well as pure propane imported from Saudi Arabia. The main problems identified during the tests were as follows: 1. Apart from the ordinary household gas produced by the Shuangyang oil extraction plant, liquefied petroleum gas produced by other refineries, including pure propane manufactured by the Jihua Refinery and pure propane imported from Saudi Arabia, all exhibited the problem of severe clogging of the evaporators due to yellow powder. According to the test reports, these plant gases have a low sulfur content; the vast majority of them do not exceed the limits specified in the quality standards for liquefied petroleum gas intended for use in vehicles set by the Petroleum and Natural Gas Corporation. 2. The ordinary household liquefied petroleum gas produced by the Jilin and Qiange oil refineries contains a high level of butadiene, which results in the formation of large amounts of gel-like polymers in the evaporator. When large quantities of this gas are used, it leads to unstable gas supply, affecting the proper operation of vehicles ； 3. Corrosion of gas-carrying copper pipes is relatively severe at the Daqing Nanyuan Refinery and Shuangyang Oil Production Plant. 4. In winter, free water sometimes appears in the aforementioned gas sources during use, causing blockages in the gas transmission pipelines. To address the aforementioned issues, at the beginning of this year, we first organized relevant personnel to conduct qualitative and quantitative analyses on the yellow powder samples generated by the evaporator during driving tests. At the end of April this year, our analysis results of the yellow powder were verified by the same analysis conducted by the Planning and Design Institute of the Petrochemical Corporation. Further research was conducted to develop technical solutions for removing the aforementioned harmful substances. In accordance with the requirements of the removal technology, three liquefied petroleum gas refining towers with an annual processing capacity of 200 tons were constructed, and desulfurization agents capable of removing elemental sulfur and sulfides from liquefied petroleum gas were selected and installed. Simulated industrial tests were conducted to remove elemental sulfur and sulfides from pure propane produced by Jihua Refinery, as well as liquefied petroleum gas produced by two refineries in the Daqing area with high LPG production volumes (over 300,000 tons per year), and liquefied gas produced by Shuangyang Oil Extraction Plant. The entire experiment lasted 57 days, from June 10, 1999, to August 6, 1999. By exploring the optimal removal process through various process operation conditions, a total of 2,377 kg of different gases were removed, including 2,290.3 kg of refinery catalyzed liquefied petroleum gas with mixed components, 86.7 kg of pure propane from Jihua Refinery, and 234 kg of associated gas from oil fields. To verify the removal efficiency of the removal device under low-temperature conditions, during the experiments we moved the test device to a cold storage twice. After freezing the test device and the test gas in the cold storage for 24 hours, low-temperature removal tests were conducted. Tests were conducted to remove elemental sulfur and polysulfides from 300 kg of liquefied petroleum gas at temperatures ranging from -3°C to 7°C. To verify the removal efficiency, we first developed testing methods for measuring the contents of elemental sulfur and polysulfides in both the feed gas and the output gas; we also fabricated the necessary testing equipment, and conducted comparative analyses of the elemental sulfur and polysulfide levels in these gases in batches, in accordance with the experimental requirements. On the other hand, the raw gas reference samples and the finished gas were supplied respectively to the gas testing vehicle with license plate number 606 belonging to Team 115 of Bus Route 64, as well as to the taxis with license plates Ji A24019 and Ji AA9482, in order to conduct driving comparison tests and 15-condition full-vehicle testing. Among them, the 606 test vehicle from route 64, team 115, was used in total for 7150 kg of pure propane sourced from various refineries before it was removed, as well as pure propane imported from Saudi Arabia and that produced by Jihua Refinery ； 1439 kg was used for the gas treatment to remove elemental sulfur and polysulfides ； 825.9 kg of gas containing elemental sulfur and polysulfides was tested using Ji A24019 and Ji AA9482 respectively. The results obtained from analytical comparisons and field tests showed consistency, confirming that the selected process units are effective in removing elemental sulfur and polysulfides from liquefied petroleum gas, with an overall efficiency of over 94%. By setting the industrial production parameters according to the optimal process conditions identified through testing, and by refining the liquefied petroleum gas produced by specific refineries for use as vehicle fuel, it is possible to ensure that Volkswagen Sagitar cars can travel 74,000 kilometers and bus vehicles can travel 12,000 kilometers without any clogging occurring in the engines. In summary, tests have shown that the production process we selected – one that operates at room temperature in a liquid phase to effectively remove elemental sulfur and polysulfides, as well as mechanical impurities and water, from liquefied petroleum gas – is technically feasible. It has also been proven that a slightly higher content of olefins (other than dienes) in vehicle fuel (up to ≤40%) does not affect the normal operation of the vehicles. The successful testing of the simulation device not only resolved the issue of elemental sulfur and polysulfides, which are commonly present in liquefied petroleum gas and cause blockages in vehicle-related equipment – a problem that has so far received little attention in the research and development of liquefied petroleum gas for use in vehicles in our country – but also provided valuable technical data for the design and operation of large-scale industrial production of liquefied petroleum gas for vehicle use.