【History of Haichuan Chemical】60 Years Since China’s First Industrial Natural Gas Desulfurization Unit Was Put into Operation: A Half-Century of Progress in China’s Natural Gas Purification and Chemical Industry

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The Path of Recovery for China’s Natural Gas Purification and Chemical Industry Over a Half Century: On a slope in Zhuan Tang Town, ** District, Chongqing, a stone tablet stands quietly, inscribed with “Former Site of the Dongxi Desulfurization Plant at the Shigou Gas Mine”. What is little known is that behind this stone tablet lies a story related to **the vital aspects of energy supply**. In December 1965, China’s first industrial natural gas desulfurization facility was put into operation here, with a daily processing capacity of only 150,000 cubic meters. This small workshop serves as a delicate umbilical cord, linking the birth and growth of China’s natural gas purification and chemical industries. Sixty years later, on December 3–4, 2025, at the Southwest Oil and Gas Field Company’s 60th Anniversary Technical Symposium on Natural Gas Purification and Chemical Processing held in Suining, Sichuan, over 200 representatives from the energy sector were present to witness this historic moment: from the construction of China’s first industrial desulfurization facility in Dongxi in 1965, to today’s daily natural gas processing capacity of over 110 million cubic meters, this oil company, tasked with ensuring energy security, has managed to increase its purification capacity by 600 times over the course of six decades. At present, the Southwest Oil and Gas Field Company not only provides a solid guarantee for gas supply for domestic use in Sichuan and Chongqing, but also supplies gas to more than 20 large and medium-sized cities in the southwest and central China. In addition, the company also supplies XAI gas for the aerospace industry, providing strong support for major projects such as satellite launches; it is truly a vital energy source that contributes to the implementation of development strategies and drives regional economic growth. The first ray of light in the wasteland: In the 1950s, not long after the founding of the People’s Republic of China, with numerous tasks to be carried out and a shortage of energy, it became urgent to explore and utilize oil and natural gas domestically. Thus, a series of oil exploration campaigns began, and large and medium-sized gas fields were successively discovered across Sichuan. However, in 1963, with the completion of China’s first large-diameter, long-distance gas pipeline—the Bayu Gas Pipeline—people realized that the pipelines were rapidly corroded by sulfur-containing natural gas during gas transmission. Moreover, natural gas contained harmful substances such as water, sulfides, and carbon dioxide, making it impossible to use it directly; therefore, the need to purify natural gas in China became urgent. There were no precedents in the country, and the international environment at that time made it impossible to obtain additional technical support from abroad; thus, the older generation of oil industry professionals had to figure things out on their own, moving forward in isolation. Zhang Hua is one of the “pioneers”; “It’s a large mountainous area, surrounded by mountains on all sides.” ”Recalling the winter of 1965, he, who had just graduated from Wuhan University, came to Dongxi and spent time in simple thatched cottages researching materials and mastering techniques. During the same period, the desulfurization research team at TIARI, led by Yang Zhilian, was also carrying out research on \"the use of monoethanolamine to remove hydrogen sulfide from natural gas\", traveling between Changshou Xincheng and Weiyuan to work on plant design and pilot tests. These young people explored the mysteries of the desulfurization process using the most primitive methods. The successful commissioning of the Dongxi facility was like the first ray of light in the darkness, illuminating the journey of exploration for generations of oil workers. This is the first amine-based system equipped with sulfur recovery in China’s gas purification industry, proving that the Chinese are capable of mastering natural gas purification and chemical engineering technologies. The transformation from student to excellent teacher: In 1977, with the development of the Wolonghe gas field, **the import of complete sets of foreign purification equipment was approved for the first time. A large number of foreign experts arrived with their patented technologies, but this also drew skeptical looks. ““They didn’t believe we could master these technologies and operate this equipment,” recalled Li Changquan, who has been retired for many years, still feeling somewhat excited. It was under such scrutinizing eyes that the original builders lived in shacks and ate dry rations; under extremely difficult conditions, they spent three years building what was at the time Asia’s largest, most fully equipped, and most technologically advanced natural gas purification plant. This system has also served as a springboard for breakthroughs in natural gas purification and chemical engineering technologies. In 1998, China’s first natural gas purification plant – designed and built independently with the highest processing capacity – was put into operation, and a selectively desulfurization solvent developed through independent research was used for the first time ； By 2025, the commissioning of new plants in Yanting, Dazhou and other locations will further indicate that China has reached international leadership levels in the field of cryogenic treatment across the entire natural gas value chain under various operating conditions, as well as in the development of the entire industrial chain for ultra-high sulfur content gas fields. In fact, the turning point occurred long after the turn of the millennium. Former students have become excellent teachers, and batches of experts in Chinese natural gas purification and chemical engineering technologies have gone abroad to participate in the construction and operation of natural gas purification and chemical processing facilities in countries such as Kazakhstan and Turkmenistan, contributing to the implementation of the Energy Cooperation Initiative under the Belt and Road Initiative. A new chapter in digital transformation: As the wave of digitalization surges forward, at this new historical moment, the Southwest Oil and Gas Field is writing a new chapter in the high-quality development of natural gas purification and chemical industries. China National Petroleum Corporation’s first intelligent natural gas purification plant was established – the Dazhu branch of the Natural Gas Purification Complex, enabling the facility to \"think and breathe\"” ； During the construction of the Ziyang branch of the Natural Gas Purification Complex in the new production area, digital delivery on a positive basis was achieved for the first time in China’s natural gas purification sector ； The Real-Time Optimization System (RTO) and Advanced Process Control System (APC) monitor the operation of the equipment 24/7, effectively reducing production energy consumption and reliance on experience ； Industrial 5G private networks, inspection robots, the “Safe Eye” system, intelligent safety helmets, and more – all these elements contribute to endowing the traditional and robust oil and gas industry with agility and intelligence, offering a unique \"Xiyou Solution\" for the digital transformation of this industry. Transformation is not merely about intelligence; it also involves sustainability. The diversified approach of using natural gas alongside new energy sources represents another outstanding achievement by the company. It has established CNPC’s first methane management demonstration project, as well as a pilot enterprise for carbon emission monitoring ； Through excess pressure power generation technology, over 60 million kWh of clean electricity is generated each year, enabling cost reduction and improved efficiency ； China’s first pilot project for CCUS-EGR has turned carbon into a valuable asset: 100,000 tons of carbon dioxide were injected into underground formations, resulting in an increase in recovery rates of around 10%, thereby achieving both increased reservoir storage and reduced emissions… These practical examples are all vivid illustrations of the harmonious coexistence between clean energy and a better quality of life. Over the past six decades, China’s natural gas purification and chemical industry has transformed from a follower to a leader. Today, the Southwest Oil and Gas Field Company stands as a leader in natural gas purification in China. Core technologies such as desulfurization, sulfur recovery, and exhaust gas treatment have reached international advanced levels, among which the advanced amine solution regeneration technology is at the international leading level. Led the development of over 10 international standards and 165 **industry standards, and obtained 104 invention patents. From the initial sparks that emerged in Dongxi, to becoming the backbone of energy security, the goal of achieving \"high-quality production of 50 billion\" is now within reach. Six decades of hard work have proven one thing: only by mastering core technologies can we ensure that we hold the keys to our energy supply in our own hands. Standing at the site of the old Dongxi facility and gazing at the dark-green mountains in the distance, one seems to hear the echoes of history – the roar that accompanied the activation of the first set of facilities in 1965, as well as the powerful rhythm of today’s processing capacity of over 110 million cubic meters per day; it is also the steady and strong pulse of China’s energy security.