Data showsIn 2022, the world emits about 38 billion tons of carbon dioxide per year, and CCS captures only one-thousandth of the carbon dioxide emissions.
Carbon capture and storage (CCS) is the process of separating, treating and transporting relatively pure carbon dioxide (CO2) from industrial sources to long-term storage sites. For example, the CO2 stream to be collected may come from the combustion of fossil fuels or biomass. Typically, CO2 is captured from large point sources, such as chemical plants or coal power plants, and stored in underground geological formations. The aim is to reduce greenhouse gas emissions and thus mitigate climate change.
There are a number of laws and regulations around the world that support or require the use of CCS technology. In the United States, the Infrastructure, Investment, and Jobs Act of 2021 supports a variety of CCS projects. In 2023, the EPA issued a rule that would require a 90% reduction target for existing coal- and gas-fired power plants to promote the adoption of CCS. Other countries are also developing plans to support CCS technology, including Canada, Denmark, and moreChinaand the United Kingdom. A 2020 study concluded that only half the amount of carbon capture and storage that could be installed in coal-fired power plants, mainly in China and India. However, a 2022 study concluded that CCS is too expensive for coal power in China.
Capturing CO2 is the most cost-effective in large fossil fuel energy plants, industries that emit large amounts of CO2 (e.g., cement production, steelmaking), natural gas processing, synthetic fuel plants, and fossil fuel-based hydrogen production plants.
In the presence of CO2 impurities, especially in air trapping, various separation technologies are being pursued in the pursuit of research, including:Gas phase separation, liquid absorption, solid adsorption, and adsorption membrane systemsand other mixing processes. Trapping can be done in three ways:Post-combustion capture, pre-combustion capture, and oxygen combustion
In post-combustion trapping, CO2 is extracted after burning fossil fuels – a scenario that applies to fossil fuel power plants.
Pre-combustion technology has been widely used in fertilizers, chemicals, gaseous fuels (H2, CH4) and power production. In these cases, fossil fuels are partially oxidized, for example in a gasifier. The CO of the resulting synthesis gas (CO and H2) reacts with the added vapor (H2O) and is converted to CO2 and H2. The CO2 produced can be obtained from relatively pure exhaust gases**.
In oxy-combustion, the fuel is burned in pure oxygen, not in the air. In order to limit the resulting flame temperature to a level common in conventional combustion, the cooled flue gases are recycled and injected into the combustion chamber. The flue gas is mainly composed of CO2 and water vapor, the latter of which is condensed by cooling.
Various methods have been used to store carbon dioxide permanently. These methods include the storage of carbon dioxide in deep geological formations, including brine forms and depleted natural gas fields, and solid storage by reacting carbon dioxide with metal oxides to form stable carbonates.
Oilfields, natural gas fields, brine formations, non-mineable coal seams, and salt-filled basalt formations have all been proposed as alternatives.
CO2 can be sequestered for millions of years, and although some leaks may occur, a proper storage site may retain more than 99% of CO2 for more than 1,000 years.
Mineral storage is not considered to pose any risk of leakage.
Norway's Sleipna gas field is the oldest industrial-scale storage project. An environmental assessment conducted after ten years of operation concluded that geological storage is the most reliable method of permanent geological storage.
Large-scale carbon dioxide releases pose a risk of suffocation。For example, in the Menzengraben mine disaster in 1953, thousands of tons of carbon dioxide were released, suffocating people 300 meters away. 14 people collapsed on a nearby road after a carbon dioxide industrial fire extinguishing system in a large warehouse failed, releasing 50 tons of carbon dioxide.
Cost is an important factor affecting CCS. The cost of carbon capture and storage, plus any subsidies, must be lower than the projected cost of emitting carbon dioxide to be considered economically profitable.
Carbon capture and storage technologies are expected to use 10 to 40 percent of the energy generated by power plants. That is, it is impossible to spend a lot of money to do big things, although Fang ** has been proposed for a long time, but the progress is slow. If a coal power plant is equipped with carbon capture equipment, you can imagine the price of electricity, at which point renewable electricity will be the lowest energy source. This approach is clearly not compatible with today's coal power and chemical plants, which makes it possible to have carbon capture and storageFossil fuel power plants struggle to compete with renewables, especially as the cost of renewables and batteries continues to fall.
At the beginning of the 21st century, carbon capture and storage trials at coal-fired power plants were not economically viable in most countries, including our country, in part because revenues from boosting oil and gas** collapsed with the 2020 oil price crash.
For most cases, alternative technologies should be used, not emissions and then pay for capture, and for the problems that you can solve, you should solve by not producing carbon dioxide" which is another sound. According to the Global CCS Institute,The CCS capacity in operation in 2020 was approximately 40 million tonnes of CO2 per annum, and the capacity under development was approximately 50 million tonnes per annum. By comparison, the world emits about 38 billion tonnes of CO2 per year, so CCS captured only one-thousandth of the CO2 emissions in 2020.