What are the CCS technologies for CO2 trapping and storage

On August 6, 2012, China's first full-process demonstration project for carbon dioxide storage to the underground saline aquifer was completed and put into operation, and more than 40,000 tons of carbon dioxide have been sequestered, making a breakthrough in the field of carbon capture and storage (CCS) technology.

The 100,000-tonne-a-year "CCS" demonstration project, implemented by Shenhua Group, China's largest coal company, is an environmental protection supporting project of China's million-ton coal direct liquefaction demonstration project, and is listed as a key scientific research project of the National Science and Technology Support Program.

Zhang Dongxiao, dean of Peking University's Institute of Clean Energy, believes that "CCS" is expected to become the single technology with the largest share of carbon emissions reduction in the world. Because of the large amount of carbon dioxide emitted by industry, the geological structure with the greatest potential is the saline aquifer, which alone can store tens of billions of tons of carbon dioxide in the saline aquifer beneath the Ordos Basin, which is more common in China. The long-term operation of this demonstration project will make a positive exploration for China's construction of a coal-based low-carbon energy system, and help it make more contributions to the clean use of coal resources and greenhouse gas emission reduction.

Carbon capture and storage (CCS) is a technology that captures carbon dioxide from sources such as large power plants, steel mills, and chemical plants, and stores it in various ways to prevent it from being emitted into the atmosphere.

Wang Shifeng CCS refers to the process of separating carbon dioxide produced by industry and related energy industries through carbon capture technology, and then transporting it to a storage site through carbon sequestration and isolating it from the atmosphere for a long time. In general, if CCS units are installed, CO2 emissions will be reduced by 85 to 90 per cent using existing technologies to capture CO2 in new power plants.

The International Energy Agency (IEA) is optimistic about this technology, and says that CCS could reduce global carbon emissions by 20% by 2050. The United Nations Climate Change Commission (UNFCCC) has identified CCS technology for coal-fired power plants as the most important technical direction for the 2050 greenhouse gas reduction target.

Coal-fired power plants generally implement CCS technology through two major means: one is to retrofit existing power stations with carbon dioxide capture devices, and the other is to establish a cleaner integrated coal gasification combined cycle power generation system (IGCC) and install CCS devices.

Regardless of the approach, CCS technology has significant drawbacks. The first is that it is an energy-intensive technology in its own right, and the CCS device applied in power plants will reduce the power generation efficiency of power plants and increase the cost of power generation.

According to the calculation of green coal power, for different power generation technologies, only the process of capturing carbon dioxide will increase the cost of power generation is not consistent, with natural gas combined cycle power stations increasing by 35% to 70%, supercritical pulverized coal power stations increasing by 40% to 85%, and IGCC power stations increasing by 20% to 55%.

For example, Huaneng Beijing Thermal Power Plant, the only project in China to achieve industrial-scale application of carbon capture technology in thermal power plants, emits about 4 million tons of carbon dioxide per year, of which the carbon capture system can capture about 3,000 tons, and the capture energy consumption accounts for more than 30% of the power plant's energy consumption.

Another problem is that CCS does not yet have a clear commercial application model, i.e., there are limited commercial applications for captured CO2, and if it is sequestered, it is costly.

As far as the utilization of carbon dioxide is concerned, its physical properties can be used as additives for carbonated beverages, welding shielding gas, air conditioning preservatives, tobacco expanders, or carbon-containing chemicals based on chemical properties. However, it is important to note that the use of CO2 does not necessarily reduce CO2 emissions.

Developing countries have no obligation to reduce emissions and can explore this aspect, but the United States, as a developed country, will be subject to many restrictions on the use of carbon dioxide if the goal of reducing emissions by 80% by 2050 proposed by Obama can be passed by Congress.

However, if carbon dioxide is sequestered, it is difficult to decompose because its molecular structure is very stable, so it can usually only be used as an oil displacement agent for enhanced oil exploitation or deep-sea storage, which is not only very costly, but also in marine storage, people do not have a comprehensive understanding of the consequences of carbon dioxide reducing the pH of the ocean.

a carbon dioxide is used for plant photosynthesis and is the main component of the atmosphere, and cannot be caught in full, so a is wrong;

b Sodium peroxide** is high, and carbon dioxide in the atmosphere should be absorbed through afforestation, so b is false;

c isotopes are applicable to atoms, and 16o = c = 18o and 16o = c = 16o are both molecules of carbon dioxide, so c is wrong;

d carbon dioxide and water or hydrogen can produce methanol under certain conditions, so d is correct so d is selected