Direct supply to coal chemical industry: How does the first coal transport pipeline function?

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The Shenwei coal pipeline, China’s first coal transport pipeline with a total investment of 7.3 billion yuan from Shaanxi Coal and Chemical Group, is about to be completed. As Asia’s longest coal transport pipeline, its operation will link the coal resources in northern Shaanxi with the water resources in Guanzhong region. “\"Converting coal into chemicals wherever possible\" is a common practice among large domestic coal companies. Shaanxi Coal Chemical Group has also developed two main business sectors: coal mining and coal chemical processing. However, due to constraints such as water resources, the chemical enterprises of Shaanxi Coal and Chemical Group are mostly located in the Guanzhong region of Shaanxi, which is rich in water sources; the coal required for these enterprises must be transported from northern Shaanxi via railways and roads. A representative from Shaanxi Coal and Chemical Group said, \"Most of our high-quality coal resources are located in northern Shaanxi. Our coal chemical enterprises, such as Pucheng Clean Energy Company, Shaanxi Chemical Industry, and Weihe Chemical Industry, are all situated in the Weinan area. Therefore, there is a demand for raw materials, and the construction of coal pipelines is driven by this need.\" ”The several coal chemical parks planned by Shaanxi Coal and Chemical Industry Group face a significant shortage of raw coal each year. The three ongoing projects in Pucheng, Weihua, and Shaanxi Chemical require over 13 million tons of raw coal per year. It is understood that the Shenwei coal transport pipeline project is China’s first coal transport pipeline. Its starting point is located in the Shenfu mining area, while its endpoints are at Pucheng Clean Energy Chemical Co., Ltd., Weihe Coal Chemical Group, and Shaanxi Chemical Coal Chemical Group. The pipeline passes through 15 counties and districts including Shenmu, Yan’an, and Weinan, with a total length of 748 kilometers. Its designed annual coal transport capacity is 10 million tons. To date, a total of 716 kilometers of piping have been welded, accounting for 98% of the overall amount ； 693.8 kilometers of backfilling has been completed, accounting for 95% of the total amount. Only the 14.32 kilometers of the Yulin section remain unfinished in the entire project. How is solid coal transported through pipelines? It has become common for oil and gas to be transported through pipelines. So can solid coal also be transported through pipelines? When transporting coal through pipelines, it is first necessary to convert the solid into a slurry by adding liquid to it, and then transport this slurry via pipelines. This technology appeared in the United States in the 19th century, but its practical application did not occur until the mid-20th century. Globally, the United States once built a pipeline that transported material at conventional concentrations, which operated successfully for 35 years but has been shut down in recent years. The Soviet Union also built one, but it became clogged and was scrapped after operating for a short time due to the excessively high concentration of coal slurry. In our country, Tsinghua University and Tangshan Coal Mining Institute have carried out theoretical research and experiments, and pipeline coal transportation technology has become largely mature. In 2016, Shaanxi Chemical Corporation conducted tests on the concentration of piped coal slurry. Regarding the operation mode of the Shenwei coal transport pipeline, officials from the Wuhan Design and Research Institute of China National Coal Group, which was responsible for the project design, explained that this project utilizes wet coal grinding technology to convert high-quality bitcoals suitable for gasification in Shenmu into conventional coal slurry with a concentration of 53%. After passing through five pressure boosting stations, the coal slurry is sent via pipelines to the coal slurry reception station. Since the concentration of the coal slurry supplied by Shenwei Pipeline Company (the primary slurry) is only 53%, whereas the concentration of water-coal slurry required for the operation of the gasifiers at Shanxi Coal Chemical Company, one of the users affected by this disruption, is at least around 60%. Therefore, secondary processing of the slurry is necessary to increase its concentration, in order to produce a coal slurry that meets the requirements of the gasification furnace. During the production process, the coal slurry needs to be mixed with a certain proportion of dry coal and additives. Furthermore, the entire pipeline operates in a buried and sealed manner; aside from the starting point, intermediate pumping stations, valve rooms, and the terminal industrial site which require permanent land use, the outdoor pipelines are buried beneath the permafrost layer, allowing the land to be reused almost immediately after construction. The project wasn’t smooth sailing, but the construction of this project was by no means easy. The builder of the pipeline, Shaanxi Shenwei Coal Pipeline Transportation Co., Ltd., was established in 2011. The project was originally scheduled to start construction in May of the same year, begin trial production in August 2013, and be completed and accepted in June 2014. It is obvious that the actual progress of the project is significantly behind schedule. The problems lie in two main areas: raising funds for the project and local coordination. Some experts say that, based on past experience, coal transport pipeline projects are often built across different regions, and the most difficult aspect is coordinating with local authorities. For the Shaanxi Coal Chemicals project, since the entire operation takes place within Shaanxi Province, it was initially expected that there would be few obstacles, but it turned out to be too optimistic. Those involved in pipeline construction also admitted to a reporter from NBD that: \"There are indeed issues with communication when coordinating with local authorities, and we have encountered situations such as exorbitant pricing, which has created certain obstacles.\" ” According to the China Business News, “Shaanxi Coal Chemical’s lack of funds caused delays in the construction of this coal transport pipeline, which was supposed to be completed by June 2014.” ” Regarding the remaining work, relevant sources said, “The group has ordered that preparations be made for the operation of the pipelines, with the goal of completing the entire project by the end of the year at the latest.”