CARBON DIOXIDE CAPTURE, UTILIZATION AND STORAGE TECHNOLOGY: REDUCE CARBON AND INCREASE PRODUCTION

CARBON DIOXIDE CAPTURE, UTILIZATION AND STORAGE TECHNOLOGY: REDUCE CARBON AND INCREASE PRODUCTION

Today, when carbon neutrality is frequently mentioned, people are exploring the possibility of energy saving and carbon reduction in various directions, such as the popularity of new energy vehicles, the overlapping of photovoltaic industry, and the planning of afforestation. At the same time, more carbon reduction technologies, such as carbon dioxide capture, utilization and storage (CCUS) technology, are also being looked at. This technology refers to the capture of carbon dioxide from industry or other carbon emission sources, and transport to a specific location for utilization or storage. It has the characteristics of large emission reduction scale and obvious emission reduction benefits, so it is vividly called "carbon catcher".

At present, there are two kinds of mature carbon dioxide storage methods: geological storage and mineral storage. Geological sequestration is the injection of supercritical carbon dioxide (a mixture of gas and liquid) into deep geological structures for storage. Common geological structures suitable for carbon sequestration include oil fields, gas fields, brackish water beds, and unexploitable coal mines. These natural deposits are large and widely distributed, but the risk of carbon dioxide leakage must be considered due to changing reservoir stress fields and geological structures such as natural fractures and faults, experts said. Therefore, the academic community is actively looking for a good way to monitor the carbon dioxide transport process in real time. After investigation and calculation, the selected geological storage sites can be stored in the stratum for more than one thousand years under strict management.

Geological sequestration is only a simple physical sequestration method, while the other mineral sequestration method requires a series of chemical reactions (mainly the exothermic reaction of CO2 with minerals containing Mg and Ca) to convert gaseous carbon dioxide into stable solid carbonates (mainly magnesite and calcite) with the assistance of catalysts. In contrast to geological sequestration, solid carbonate minerals have no risk of leakage and can permanently sequester carbon dioxide without harm to the environment.

In August this year, China's first one-million-ton CCUS(Carbon capture, Utilization and storage) project was completed.

Chemical enterprises are "large" carbon polluters. Limited by product characteristics, they still need to consume a large amount of fossil energy even after improving the process and optimizing the energy structure, with rigid carbon dioxide emission and heavy carbon reduction pressure. For oil fields, enhanced oil recovery techniques using highly purified carbon dioxide are feasible. Through cryogenic and compression technology, as well as self-developed capture equipment, this is also the core principle of the operation of the project. After the project is officially operational, the petrochemical enterprise can recover 1 million tons of carbon dioxide every year. The captured carbon dioxide is transported by special transport vehicles to an oil field 80 kilometers away. There, more than 10 unmanned filling stations will fill nearby injection Wells around the clock.

So what is the use of injecting carbon dioxide into oil fields? In fact, injected into the reservoir, the purified carbon dioxide can increase the flow of oil and "reveal" oil that would otherwise be trapped in cracks in the formation, thus greatly enhancing oil recovery. Co2 flooding is 40% more efficient than water and is expected to add nearly 3 million tons of oil over the next 15 years.

In this cooperative mode, the utilization of carbon dioxide is not only the application of new oil displacement methods, but also the underground storage of carbon dioxide injected into the field. While some of the carbon dioxide still escapes during production, 60 to 70 percent of it can be sequestered at a time. The fraction that escapes is captured by the field's own "associated gas capture and injection system" and injected back into the well, eventually bringing the recovery rate close to 100%.