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Faced with the dilemma of declining profits in refined oil production, the technology for converting crude oil into chemicals (COTC) could become the next direction for refiners to pursue. In recent years, some companies have raised the level of integrated refining and petrochemical production to a new stage of Crude Oil to Chemicals (COTC) by integrating innovative approaches into traditional refining processes or by completely overhauling those processes. Based on the current technological landscape and future trends, COTC technologies can be divided into two categories: maximizing the production of chemicals from crude oil, and producing chemicals directly from crude oil. In terms of the yield of converting crude oil into basic petrochemical feedstocks, the yields for various processes are roughly as follows: 5%–10% for traditional fuel-oriented refineries, 10%–20% for conventional integrated refining and chemical plants, and over 40%, or even up to 80%, for plants that produce chemicals from crude oil. Commercial projects 01 | Direct conversion of crude oil into chemicals (olefins), with ExxonMobil as a representative. ExxonMobil was the pioneer of COTC projects. The company’s 1 million tons per year ethylene plant located on Jurong Island in Singapore is the world’s first COTC project. In January 2014, ExxonMobil put into operation an olefin production facility using direct steam cracking of crude oil at its chemical plant in Singapore, capable of producing 1 million tons per year of ethylene directly from crude oil. The project is integrated with its refinery, not only sharing utility services but also obtaining heavy fuel feedstocks from the refinery for olefin production. The most notable feature of ExxonMobil’s technology for producing olefins through direct steam cracking of crude oil (the process flow is shown in Figure 1) is the elimination of refining units such as atmospheric and vacuum distillation, which significantly simplifies the process flow. Figure 1 shows a schematic diagram of the process for directly converting ExxonMobil’s Singapore crude oil into olefins. Its innovation lies in bypassing the conventional refining process entirely by feeding the crude oil directly into the steam cracking furnace, with a flash tank added between the convection section and the radiation section of the furnace. The crude oil processing capacity of ExxonMobil’s plant in Singapore is close to 30 million tons per year, while its capacity for producing basic petrochemical feedstocks exceeds 8 million tons per year, with a yield of around 24%. 02 | Maximizing the conversion of crude oil into chemicals, exemplified by Hengli Petrochemical and Zhejiang Petrochemical. The maximization of crude oil conversion into chemicals relies on traditional petrochemical processing technologies that have been optimized in order to produce as many chemical raw materials as possible for use in integrated petrochemical plants. This route converts heavy products such as wax oil and residue in the crude oil refining process into lighter products by adding additional processing units like hydrocracking, while also increasing the hydrogen-to-carbon ratio. By utilizing existing mature technologies and through reconfiguration, the yield of basic petrochemical feedstocks can be significantly increased to 40%~50%. Private enterprises in our country are already using advanced domestic and international refining and chemical processing technologies to build such oil refineries, including the Hengli Petrochemical project on Changxing Island in Dalian, the Zhejiang Petrochemical project in Zhoushan, and the Dongfang Shenghong project in Lianyungang. ● Hengli Petrochemical Project: This project has a crude oil processing capacity of 20 million tons per year. It primarily processes medium and heavy crude oils from Saudi Arabia or crude oils of similar quality. The refinery is designed to produce naphtha, while the aromatics complex is intended to maximize PX production. The main components of Phase I of the project include 20 million tons per year of atmospheric and vacuum distillation, 2 million tons per year of kerosene hydrorefining, 6 million tons per year of diesel hydrocracking, 7.6 million tons per year of wax oil hydrocracking, 6.4 million tons per year of residue hydrocracking, and 1.35 million tons per year of solvent deasphalting, among others ； The products include 4.5 million tons per year of PX, 1 million tons per year of pure benzene, and 1.5 million tons per year of ethylene, resulting in an annual output of over 9 million tons of basic petrochemical raw materials, with a yield of around 46%. At the end of 2018, the atmospheric and vacuum distillation unit was put into operation; in May 2019, the oil refining project was fully operational, and in January 2020, the ethylene project began trial operations. The schematic diagram of Hengli Petrochemical’s process for maximizing the conversion of crude oil into chemicals is shown in Figure 2. Figure 2 Schematic diagram of Hengli Petrochemical’s process for maximizing the conversion of crude oil into chemicals. ● Zhejiang Petrochemical Project: This project is implemented in two phases; once fully completed, its crude oil processing capacity will be 40 million tons per year. The main products will be 8 million tons per year of PX, 2 million tons per year of pure benzene, 2.8 million tons per year of ethylene, and 600,000 tons per year of propylene dehydrogenation products. The main components of Phase I of the project include 20 million tons per year of atmospheric and vacuum distillation, 3 million tons per year of light hydrocarbon recovery, 3 million tons per year of delayed coking, 5 million tons per year of residue hydrodesulfurization, 3.8 million tons per year of wax oil hydrocracking, 8 million tons per year of diesel hydrocracking, 4.2 million tons per year of heavy oil catalytic cracking, and 2 million tons per year of catalytic gasoline hydrogenation. The annual production of petrochemical products is approximately 9 million tons, with a yield of basic petrochemical feedstocks of around 45%. In May 2019, the first phase of the project was launched with the operation of the atmospheric and vacuum distillation units, and full production commenced by the end of 2019. Phase 2 commenced construction in March 2020, with completion and operation expected by 2022. New technologies for converting crude oil directly into chemicals: The technological approaches for converting crude oil directly into chemicals bypass the conventional atmospheric and vacuum distillation steps in refineries. Saudi Aramco is working on developing various technical approaches for COTC, including the Technology for Chemicals from Thermal Crude (TC2CTM) and the Technology for Chemicals from Catalyzed Crude (CC2CTM); different types of crude oil will be used in each of these technologies. Saudi Aramco’s R&D center in Dharan is also researching other undisclosed, high-risk, high-return COTC technologies. In addition, Reliance Industries in India is developing the MCC process, while SINOPEC’s Research Institute focuses on developing process routes for catalytic cracking. ● SABIC’s TC2CTM technology route: SABIC’s patented TC2CTM technology utilizes integrated hydrogenation, steam cracking, and coking processes to directly process crude oil in order to produce olefin and aromatic petrochemical products as well as petroleum coke, as shown in Figure 3. Figure 3: Schematic diagram of the TC2C process for producing chemicals from Saudi Aramco’s thermal crude oil. It is reported that this technology can increase the yield of basic petrochemical feedstocks to 70%~80%. In January 2018, Saudi Aramco signed a joint development agreement with McDermott and Chevron Luvs Global (CLG), utilizing McDermott’s ethylene technology, CLG’s hydroprocessing technology, and Saudi Aramco’s proprietary TC2CTM technology to provide a platform for this joint development. In June 2018, Saudi Aramco Technology Company signed a technology licensing agreement with the U.S.-based Siluria Technologies to integrate Siluria’s methane oxidation coupling technology for ethylene production with Saudi Aramco’s TC2CTM technology, thereby further increasing the yield of ethylene. It is also reported that in 2019, Mc Dermott acquired the methane oxidation coupling technology for ethylene production held by Siluria. ● Saudi Aramco’s CC2CTM pathway: In January 2019, Saudi Aramco’s technology company formed a technical alliance with Technip FMC and Axens to accelerate the development and commercialization of the CC2CTM technology. The agreement calls for completing the commercialization preparations for CC2CTM technology by 2021. CC2CTM technology is an innovation built on the proven high-severity fluidized catalytic cracking (HS-FCCTM) technology. HS-FCCTM was developed by Saudi Aramco in collaboration with King Fahd University of Petroleum and Minerals and Japan’s JXTG Energy Group. Saudi Aramco, Axens, and Technip FMC are all members of the HS-FCCTM technology alliance; Axens and Technip FMC are also the exclusive license holders for the HS-FCCTM technology. The schematic diagram of Saudi Aramco’s CC2CTM technology process is shown in Figure 4. Figure 4: Schematic diagram of Saudi Aramco’s CC2C process for converting crude oil into chemicals. ● Reliance Industries’ MCC technology: Reliance Industries uses the multi-zone catalytic cracking (MCC) process to directly crack crude oil, without the need for atmospheric and vacuum distillation units; this technology can also be used in combination with the cracking of condensate oil, shale oil, and tight oil. The company has evaluated around 120 crude oils worldwide and determined that they are suitable for the MCC process. The levels of pollutants in these crude oils (such as vanadium) are within the limits permitted by this process. ● Sinopec’s Research Institute of Petrology’s technology for producing olefins from crude oil is based on catalytic cracking, and there are two main approaches. In the first approach, crude oil is divided into light and heavy fractions, which are then subjected to catalytic cracking to produce low-carbon olefins. This process is carried out using a catalytic cracking unit with dual lift tube reactors; the light and heavy fraction oils are fed into these reactors respectively, with optimal operating parameters applied to maximize the production of low-carbon olefins. Pilot tests for this route have been completed; pilot-scale tests were carried out in late April 2020, with industrial trials planned to take place in Yangzhou in 2021. The process challenge lies in the fact that, although naphtha and diesel fractions in crude oil have a high hydrogen content, their smaller molecular size makes them more difficult to crack; as a result, specialized catalysts and more stringent operating parameters are required. Taking the crude oil from the Jiangsu oilfield as an example, pilot test results show that the yield of ethylene + propylene reached 33%. If reprocessing C4 olefins and light gasoline is considered, the diene yield will be higher than this value. This figure is comparable to ExxonMobil’s data on direct steam cracking of crude oil in Singapore (with an ethylene + propylene yield of 35%). Adaptability to crude oil requires paraffinic crude; if it is intermediate or naphthic, the heavy fractions obtained after separation need to be hydrogenated first, or there must be a suitable hydrogenation facility available. Another approach is to separate the crude oil into its hydrocarbon components, hydrogenate the aromatics, and then subject both the aromatics and the non-aromatics to catalytic cracking. This route is still under experimental exploration, and the challenge lies in how to separate the hydrocarbon components of crude oil. Preparatory work is underway for multiple projects. COTC represents the ultimate development direction for the refining industry; in addition to the large COTC projects that are already in operation or under construction as mentioned above, Saudi Aramco is also carrying out preparatory work for COTC projects in Yanbu, Saudi Arabia, and Jamnagar, India. Saudi Aramco plans to invest $20 billion in building the COTC project in Yanbu, Saudi Arabia. The project will have a processing capacity of 20 million tons per year for Arab Light crude oil, with products including ethylene glycol, polyethylene, polypropylene, benzene, and mixed xylene. It will produce around 9 million tons per year of basic petrochemical feedstocks and base oils for category III lubricants, at an yield of approximately 45%. Saudi Aramco began feasibility studies in April 2014, with plans to complete construction and bring it into operation by 2025. The process configuration for the Yanbu COTC project has not yet been finalized. It appears that no newly developed technologies that are not yet commercially available will be used; instead, existing refining and petrochemical technologies will be utilized to maximize the production of petrochemical products. Indian Reliance plans to invest around $10 billion in building the COTC project at its Jamnagar facility in India. The main products include: 8.5 million tons per year of ethylene and propylene, 3.5 million tons per year of BTX (benzene, toluene, mixed xylene), and 4 million tons per year of PX. The establishment of new COTC projects also puts significant pressure on traditional, fuel-based refineries; in the future, some outdated refineries will be driven out of the market. Through continuous improvement, the impact of next-generation COTC technology will be even greater. For example, once Saudi Aramco’s TC2CTM technology is successfully commercialized, given its yield of 70% to 80% for basic petrochemical feedstocks, with an annual processing volume of 20 million tons of crude oil, at least 14 million tons of chemical products can be produced each year. Source: China International Petrochemical Conference