Analysis of Global CCUS Technologies and Applications

Thread Content

【Read by those in the energy sector; click the upper right corner to ‘Follow’】 By Zhao Zhiqiang, Zhang He, Jiao Chang, Wang Qiufeng, Lin Xianli, Beijing Branch of China Global Engineering Co., Ltd., Modern Chemicals 1 Introduction Carbon emission reduction is not only related to **policy commitments but also closely connected to the Earth’s environment on which we depend for survival. As early as the 1970s, foreign countries began conducting research on carbon capture. The IPCC’s Special Report on Global Warming of 1.5°C states that CCS (Carbon Capture and Storage) technologies can effectively mitigate global climate change, and it emphasizes that such technologies are crucial for achieving zero carbon emissions by 2050. In 2019, the G20 Energy and Environment Ministers’ Meeting included CCUS technology in its agenda for the first time. Foreign researchers have conducted extensive studies on carbon capture. Leee et al. utilized solid absorbents to capture carbon dioxide (CO2) in order to reduce CO2 emissions from various combustion processes. The absorbents used could be recovered through heating or reduced pressure. As a mature technology for CO2 capture, this method achieves a separation efficiency of 90%. Dutcher et al. captured CO2 using the amine technique, and due to the high reversibility of the reaction, it can be effectively applied in engineering projects. China started research on CCUS technology relatively late, with policies regarding this technology being introduced gradually beginning in 2006. “During the 11th Five-Year Plan period, an average of 3 policies were introduced each year, while during the 12th Five-Year Plan period, an average of 3 to 4 policies were introduced per year. Documents such as the \"China’s Plan for Addressing Climate Change,\" the \"Special Actions on Science and Technology for Addressing Climate Change in China,\" and the white paper \"Policies and Actions of China in Addressing Climate Change\" all identify CCUS technology as one of the key technologies to be studied. The Work Plan for Controlling Greenhouse Gas Emissions during the 13th Five-Year Plan Period proposes that by 2020, CO2 emissions per unit of GDP should be reduced by 18% compared to 2015, with total carbon emissions being brought under effective control. At the Paris Climate Conference in 2015, China pledged to peak its CO2 emissions around 2030 and to do so as soon as possible; by that year, it aimed to reduce CO2 emissions per unit of GDP by 60% to 65% compared to 2005, with non-fossil energy accounting for about 20% of total primary energy consumption. In modern industrial production, there are many sources of CO2 emissions; industries such as cement, steel, power generation, coal chemical processing, and refineries are all major contributors to CO2 emissions. In response to the issue of CO2 emissions, various industries have carried out research and exploration in the areas of CO2 capture, utilization, and storage. Each industry has developed a range of technical methods for CO2 capture, utilization, and storage based on its own industry-specific characteristics. 2 Overview of CCUS Technologies 2.1 Carbon Capture Technology The methods for capturing CO2 can be divided into three types based on the measures taken regarding fuel, oxidants, and combustion products: pre-combustion capture, oxygen-enriched combustion, and post-combustion capture, as shown in Figure 1. Pre-combustion capture is a method with relatively low costs and high efficiency. This method gasifies fossil fuels into syngas (whose main components are H2 and CO), then converts CO into CO2 through a shift reaction, and subsequently separates H2 and CO2 using methods such as solvent absorption to collect the CO2. However, this technology is limited to Integrated Gasification Combined Cycle (IGCC) systems; as a result, few projects have been implemented using it. The cost of capturing CO2 before combustion is approximately $20 per ton of CO2, and more projects are needed to verify its effectiveness. Oxygen-enriched combustion technology uses pure oxygen or oxygen-enriched air to burn fossil fuels; the main products of this combustion are CO2, water, and some inert components. After the water vapor condenses, CO2 is purified through low-temperature flashing, and the concentration of the purified CO2 can reach 80%–98% by volume, thereby increasing the CO2 capture efficiency. Since oxygen-enriched combustion achieved through pre-combustion capture requires suitable materials and operating conditions to meet the high-temperature requirements, there are few research and development efforts as well as demonstration projects for these two technologies. In comparison, post-combustion capture is a technology that is widely used and well-established in refineries today; it features high selectivity and capture efficiency. Common methods include chemical absorption, membrane separation, physical adsorption, etc. Chemical adsorption is considered to be the most promising adsorption method at present. In chemical adsorption, amine solutions are widely used due to their excellent absorption properties. With current technology, the cost of capturing CO2 after combustion is approximately $40 per ton of CO2. 2.2 Carbon utilization and sequestration technologies: Based on experiences from domestic and international projects, underground sequestration, oil displacement, and food-grade utilization are the currently dominant approaches. Figure 2 shows the main carbon utilization and sequestration technologies. 2.2.1 Carbon utilization: CCUS—EOR (Enhanced Oil Recovery) technology can link carbon sources generated by coal chemical or natural gas chemical processes with oil fields using CO2, yielding good economic benefits. As shown in Figure 3, this technology involves injecting captured CO2 into oil fields; this allows oil to be extracted from fields that are nearing exhaustion, while simultaneously storing the CO2 permanently underground. The main principle of CO2 flooding is to reduce the viscosity of crude oil and increase its internal energy, thereby improving its fluidity and raising the pressure in the oil reservoir. The commercial use of CO2 to produce fertilizers and food-grade CO2 is also a relatively mature carbon utilization project at present. In recent years, there have been many new approaches to the utilization of carbon abroad; for example, both the Netherlands and Japan have carried out large-scale projects in which CO2 generated by industry is used in gardens as a greenhouse gas to promote plant growth. Including greenhouse gas utilization technologies, carbon utilization technologies abroad that are currently in the demonstration phase include the use of CO2 to produce fertilizers, its use for oil field stimulation, and its application in food-grade products ； Areas that are currently in the development stage include polymer production from CO2, CO2 methanation reforming, methanol production via CO2 hydrogenation, algae cultivation, and power cycles ； Areas that are still in the theoretical research stage include the production of carbon fibers from CO2 and acetic acid, among others. The emerging approaches to carbon utilization in China mainly include the conversion of CO2 into methanol via hydrogenation, the conversion of CO2 into isoparaffins via hydrogenation, the conversion of CO2 into aromatics via hydrogenation, and the methanation reforming of CO2. Institutions such as the Shanxi Coal Chemistry Research Institute, the Dalian Institute of Chemical Physics, the Shanghai Institute of the Chinese Academy of Sciences, and Dalian University of Technology have conducted research on these technologies, but most of them are still at the theoretical research stage or the pilot-scale testing stage regarding catalyst development. 2.2.2 Carbon sequestration: After CO2 is captured, it can be stored for long periods by pumping it underground or underwater, or it can be stored in plants, soil, and underground sediments through enhanced natural biological processes. Current carbon sequestration technologies are mainly divided into the following two types: The first is to inject CO2, which has been liquefied under high pressure, into the ocean floor. Based on the physicochemical properties of CO2, below 2.5 km above sea level, CO2 exists primarily in liquid form. Since its density is greater than that of seawater, this area is considered a safe zone for ocean carbon sequestration, as shown in Figure 4(a). The second method is the geological sequestration of CO2. In the depth range of 0.8 to 1.0 km underground, supercritical CO2 exhibits fluid properties. Geological carbon sequestration can be achieved based on the changes in the physicochemical properties of CO2, as shown in Figure 4(b). 3 Key Progresses of CCUS Projects 3.1 Progress of CCUS Projects Abroad To address global climate change, foreign countries began conducting research on CO2 capture projects quite early on. Table 1 summarizes major international CCS/CCUS projects. The earliest large-scale CCUS project reported abroad was the Terrell project built in the United States in 1972, with a CO2 capture capacity of 400,000 to 500,000 tons per year ； Subsequently, the Enid project in Oklahoma, United States, was completed in 1982; it utilized CO2 generated by fertilizer plants to enhance oil production in oil fields, with a CO2 capture capacity of 700,000 tons per year. Norway, whose 1/3 of its territory lies within the Arctic Circle, is also one of the first countries to conduct research on CO2 capture projects. In 1996, the completion of Norway’s Sleipner project marked the world’s first initiative to inject CO2 into underground formations (saltwater layers), with nearly a million tons of CO2 being sequestered each year. Since the beginning of this century, due to the accelerated pace of industrialization and the intensifying trend of global warming, CO2 capture projects have received increasing attention. The United States, Canada, Australia, Japan, and the UAE are **accelerating the industrialization of CO2 capture projects**. In 2000, the United States and Canada collaborated to inject CO2 from the Great Plain Sysfuels Plant and SaskPower power plants into the Weyburn oil field, thereby increasing oil production from that nearly depleted field while sequestering more than 26 million tons of CO2 in total. In 2014, the Boundary Dam Power project of Canada’s SaskPower company became the world’s first CO2 capture project to be successfully implemented in a power plant. This project captures the CO2 generated by a 150MW coal-fired power plant; part of this CO2 is stored underground while another portion is used to enhance oil production in the Weyburn oil field in the United States, with a CO2 capture capacity of 1 million tons per year. Throughout 2019, the project captured 616,000 tons of CO2. In 2015, Canada’s Quest project successfully injected CO2 generated during the hydrogen production from synthetic crude oil into an aquifer for storage, with an annual CO2 capture capacity of 1 million tons per year. This project is the first CCS project in the oil sands industry, capable of reducing carbon emissions by up to 1 million tons per year. By 2019, the Quest project had captured a total of 4 million tons of CO2, achieving its targets ahead of schedule at a lower cost. Currently, the Quest project is the largest in the world for capturing CO2 and successfully injecting it underground. In 2016, the Gorgon project in western Australia was part of the Gorgon Gas Project, the world’s largest single LNG project. This project uses liquefaction technology to separate CO2 from natural gas, and the separated CO2 is injected into the saltwater layers of Barrow Island at a rate of up to 3.5 million tons per year. 3.2 Progress of existing/under-construction CCUS projects in China As industrialization accelerates, research on CO2 capture projects has also begun in China. Compared to foreign countries, China’s CCUS projects started later, and there are still no capture projects on a million-ton scale. Currently, domestic projects are mainly at the scale of 100,000 tons in terms of capture volume. Domestic CCS/CCUS projects are shown in Table 2. In 2007, the Jilin Oilfield of CNPC and the Caoshe Oilfield of Sinopec’s East China Branch marked a new chapter in domestic CO2 capture projects. Through long-term practice, the Jilin Oilfield of China National Petroleum Corporation was the first to achieve the industrialization of CCUS-EOR technology in 2007, establishing five types of demonstration areas for CO2-driven oil extraction and storage, with an annual CO2 storage capacity of up to 350,000 tons ； In the same year, Sinopec’s East China Branch established a pilot project at the Caoshé oil field for the annual injection of 40,000 tons of CO2; later, a CO2 recovery facility was built with an annual processing capacity of 20,000 tons. Subsequently, driven by the increasingly mature CO2 capture technology, Sinopec’s Shengli Oilfield, China Shenhua, Yanchang Petroleum, and Sinopec’s Zhongyuan Oilfield accelerated the industrialization of CO2 capture projects. In 2010, Sinopec’s Shengli Oilfield established China’s first CCUS demonstration project for coal-fired power plants. Utilizing the CO2 emitted from the flue gases of these power plants, and employing combustion-capture technology, the captured CO2 was injected into the oilfield to enhance oil extraction; the CO2 capture capacity reached 30,000 to 40,000 tons per year ； In 2011, Shenhua Ordos’ 100,000 t/a CCS demonstration project was completed. This project used the methanol absorption method to capture CO2 from the exhaust gases generated in coal gasification for hydrogen production, and then injected the CO2 into saltwater layers; it was the first geological storage experiment using saltwater layers in China ； In 2012, Yanchang Petroleum built a CO2 capture and utilization facility with an annual capacity of 50,000 tons. This facility utilizes CO2 generated in coal chemical processes; after purification and pressurized liquefaction using the low-temperature methanol washing technique, this CO2 is injected into oil fields, where it reduces the viscosity of crude oil, increases oil recovery rates, and enables permanent sequestration of CO2 ； In 2015, the CCUS project for refinery exhaust gases at Sinopec’s Zhongyuan Oilfield was completed. This project utilizes CO2 to enhance oil recovery from oilfields that are nearing exhaustion, increasing their recovery rate by 15%; to date, millions of tons of CO2 have been injected into the ground. In addition to traditional CO2 capture technologies, new CO2 reuse technologies have also been developed in China and applied in industries such as food and fine chemicals. In 2009, the carbon capture project at Shanghai Shidongkou No. 2 Power Plant was completed, with a capture capacity of 100,000 tons per year; the captured CO2 is primarily used in the food industry ； In 2011, as a result of research on clean coal energy power systems in Lianyungang, the CO2 generated by IGCC was captured; part of it was used in the urea and soda ash industries, while another part was injected into saltwater layers for sequestration ； In 2012, the Guodian Group CO2 capture demonstration project in Beitang, Tianjin, employed post-combustion capture technology, with an annual capture volume of 20,000 tons; the captured CO2 was used in the food industry. Furthermore, microalgae carbon sequestration technology is still in the developmental stage worldwide. In 2010, SNOW Group utilized this technology in Dalaat Banner, Inner Mongolia, to capture the exhaust gases from coal-based methanol/dimethyl ether production facilities; part of these gases was used to produce biodiesel while another part was used for other purposes, with a processing capacity of 20,000 tons per year. In addition to existing projects, the construction of CO2 capture projects in China will be accelerated; for example, Qilu Petrochemical is building a CCUS-EOR project (to be completed in 2020), with a CO2 capture capacity of 40,000 tons per year. Under some bilateral agreements, China and the United States will carry out several large-scale CCUS projects in China, such as the Sino-US Climate Change Cooperation Yanchang Petroleum CCUS demonstration project. 4 Conclusions and Outlook Industry is the foundation of modern society and a source of economic development; while it brings economic benefits and job opportunities, it also gives rise to many problems. Industry consumes one-third of the world’s energy, yet generates one-third of the world’s greenhouse gases. In the pursuit of near-zero emissions goals and the roadmap to limit global warming to 1.5°C, CCUS technology will play a crucial role. The IEA estimates that, through the use of CCUS technology, CO2 emissions can be reduced by 28 billion tons from 2017 to 2060. Next-generation carbon capture technologies will achieve breakthroughs in material innovation as well as improvements in processes or equipment. These advancements will help reduce investment and operational costs while increasing capture efficiency. Technologies such as the non-aqueous solvents from Ion Engineering, the membrane separation systems from MTR, the KS-21 solvent from Mitsubishi Heavy Industries, and the rich-poor solvent absorption and regeneration cycle technology from Lind-BASF have all been put into practice in FEED (Front and End Engineering Design) projects. With the advancement of industry, next-generation capture technologies will drive the progress and development of CCUS technology. In the coming decades, carbon utilization will play an important role in addressing global warming. Looking at mature engineering projects both domestically and internationally, underground sequestration, oil displacement, and food-grade utilization are the currently dominant approaches. Among them, oil displacement technologies can connect the carbon sources generated by coal chemical or natural gas chemical industries with oil fields using CO2, offering good returns and promising application prospects. In the future, there will be an increasing number of CCUS projects combined with hydrogen energy utilization. Currently, 98% of the hydrogen produced globally comes from non-renewable fossil fuels. Gas reforming (mainly methane steam reforming) combined with CCUS technology, along with coal gasification technology, can help achieve the goal of producing low-carbon hydrogen. The EU and some other countries have already regarded CCUS as a key element in achieving this goal; the United States, the Netherlands, Japan, Australia, New Zealand, and China have also emphasized the importance of CCUS in their hydrogen energy policies. Disclaimer: The above content is reproduced from Energy Intelligence; it does not represent the position of this platform. National Energy Information Platform: Phone number: 010-65367702, Email: hz@people-energy.com.cn, Address: No. 2 Jintai West Road, Chaoyang District, Beijing, People’s Daily Press. Source: National Energy Information Platform