【Ten Years of Rapid Development in Chemical Equipment】2259-2025: BEIHUA INSTITUTE’S Complete Set of Technologies for the Recovery and Utilization of Dry Gas in Refineries Using the Cryogenic Oil Absorption Method

The recovery rate of light hydrocarbons exceeds 93%, enabling the resource utilization of dry gas. The concept for developing this technology dates back 20 years. “International oil prices fluctuated upward in 2005, rising to $140 per barrel by 2008. At that time, China’s ethylene production relied on expensive naphtha as a raw material, resulting in high costs. Meanwhile, valuable resources such as ethylene and ethane, which are abundant in refinery dry gas, cannot be recovered due to the lack of appropriate technologies and must therefore be burned as fuel, resulting in both waste of resources and hindering carbon emission reductions. The project team identified this pain point in the industry and introduced the concept of cryogenic oil absorption – enabling efficient separation of refinery dry gas under mild conditions above 0°C – thus embarking on a path of technical research and development. ”Recalled Li Dongfeng, the chief expert at the North China Institute of Chemistry. 　　According to Li Dongfeng, this technology is based on the principle of \"like dissolves like.\" Using C₄ as an absorbent, it absorbs the \"similar\" C₂+ components present in the dry gas, thereby removing the \"unsimilar\" light components such as hydrogen, nitrogen, and methane. The resulting concentrated gas can be used directly as a feedstock for cracking, or it can be further purified and separated. 　　“At that time, cryogenic separation technology was widely used abroad, requiring operation at ultra-low temperatures below -100°C, which involved high energy consumption and large investment costs, as well as the need for thorough purification of the raw materials. Domestic separation technologies, on the other hand, suffered from issues such as complex processes, low recovery rates, and unstable operation. ”Li Dongfeng said that by conducting molecular simulations and relying on the intermolecular interaction energy, they developed composite absorbents based on butane and butylene. At the same time, they carried out measurements of high-pressure gas-liquid phase equilibria and studies on the formation patterns of hydrates, thereby solving problems such as the difficulty in separating gas and liquid at critical conditions and the blockage caused by hydrates. 　　In 2011, this technology was first applied industrially at Qilu Petrochemical, with a successful first operation that achieved an ethylene recovery rate of over 93%. The high-purity product recovered served as high-quality raw material for the ethylene plant, while also reducing production costs. More importantly, the device achieves long-term continuous and stable operation. 　　“By innovatively developing specific absorbents and processes, we have achieved the technology for absorbing and recovering dry gas using cryogenic oil for the first time, filling a gap in the international landscape. ”Li Yan, deputy director of the Production Technology Research Institute at Beijing Institute of Chemical Technology, said, “Over the 20-year research and development process, thanks to the strong support from leaders at all levels of Sinopec and Beijing Institute of Chemical Technology, as well as the continuous efforts of researchers, the shallow-cold oil absorption technology has been continuously improved and upgraded.” ”In 2020, BEIC developed a second-generation technology based on the first-generation shallow-cold oil absorption technology; this technology uses a \"high-pressure absorption–low-pressure desorption\" approach to remove methane, thereby enabling further reduction of the plant’s energy consumption by 10%~15%. Furthermore, specific optimizations were made depending on the type of raw material, enabling this technology to recover C₂, C₃, and C₄ simultaneously. Currently, second-generation technology has been applied in Hainan Refining & Chemical to recover saturated dry gas and saturated light hydrocarbons. 　　“The breakthrough from 0 to 1 was the result of the efforts of several generations of researchers. ”Liu Zhixin, a senior expert from the Beijing Institute of Chemical Technology, remarked that the project team has trained over 30 researchers through a mentorship model involving experienced professionals, middle-aged experts, and young talents. And she herself has grown from a \"newbie\" at the beginning of the project development to a project leader who can handle tasks independently.

It can reduce carbon emissions by 20 million tons per year, helping refineries cut costs and improve efficiency. In 2015, this technology was transferred to Fujian United Petrochemical for industrial use for the first time. To date, this technology has been applied in more than 20 units at large domestic petrochemical enterprises, with a market share of over 70%. 　　“The shallow cryogenic oil absorption technology is viewed favorably as it can perform absorption at temperatures above 0°C; compared to intermediate and deep cryogenic technologies, it eliminates the need for raw material purification, overcoming the limitation that traditional absorbents struggle to separate components with ultra-low boiling points at temperatures above 0°C. ”Li Dongfeng explained that this technology can also remove impurities to a high degree, reducing the levels of carbon monoxide, nitrogen, and hydrogen in the product to ppm levels, keeping the oxygen content below 1 ppm and the nitrogen oxide content below 10 ppb, thereby enhancing the intrinsic safety of downstream equipment. Furthermore, this technology can be efficiently integrated into large-scale integrated refining processes to help reduce energy consumption and waste. This technology can make full use of the excess low-temperature hot oil or low-grade steam available in refineries as heat sources, and it can also utilize the low-temperature hot water from refineries in absorption lithium bromide refrigeration units. Furthermore, the products obtained using this technology have a low methane content; when fed into ethylene plants, it reduces the energy consumed in converting methane from high-temperature cracking to deep-cold separation, thereby lowering production costs. 　　Li Yan did some calculations for the reporter: A refinery with a capacity of 10 million tons per year has more than 500,000 tons per year of dry gas available; if this gas is utilized in its entirety, it can replace 600,000 tons of naphtha, resulting in an annual cost savings of 80 million yuan. Against the backdrop of significant pressures on the current ethylene industry chain, this represents a considerable profit. 　　In addition to reducing costs and improving efficiency, this technology can also help reduce carbon emissions. “Previously, the dry gas from refineries was mostly burned as fuel, resulting in significant carbon emissions. We achieve the reuse of high-value products by recovering high-quality materials from dry gas. Currently, the scale of the plants operating under this technology package and those under construction combined is 12.44 million tons per year, with an estimated annual reduction in carbon emissions of 20.73 million tons. ”Dr. Shao Huawei, a member of the project team, explained.

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What great news! Thank you for sharing!

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Give a thumbs up to the development of chemical equipment in China – China is great!