The advantages of gasification, why carry out gasification
Thread Content
With coal gasification, there is a problem: many research institutions are working on this technology. But what are the advantages of coal gasification? Why use it? We all know that burning coal pollutes the environment, but in coal gasification, coal is first gasified and then burned; the heavy metals in coal remain in the ash (which isn’t much different from burning coal directly). Sulfur and nitrogen are also not removed as a result. Moreover, how are the impurities in the gaseous products after gasification separated? Doesn’t this add another complicated step to the process (and separating them requires additional energy)? Additionally, during coal gasification, only a portion of the coal’s energy is transferred to the gas, meaning a lot of energy is lost Of course, if gasification is intended to produce chemical raw materials such as CO and H2, I can understand that, but why go through the process of turning it into gas just to burn it? I’m a newcomer; could the experts here please explain it to me?:)
Indeed, there is considerable controversy; for example, some argue that once the coal-to-gas pipeline from Inner Mongolia to Beijing was built, Beijing gained access to clean natural gas, but the pollution remained in Inner Mongolia, where the gasification took place. But it can be viewed from another perspective: if coal is delivered to households for burning, compared to coal being gasified centrally and then sent to households, which approach do you think is better? Obviously, centralized gasification is better
OP, are you asking about gasification of coal, or coal-to-gas conversion? Coal-to-gas involves first gasifying coal to produce syngas, which is then purified and transformed, and subsequently methanized to yield methane.
**There is a rule: more than 50% of the coal must be transformed locally (? ), what to do with the rest? Only: power generation, olefin production, oil production, and natural gas production. Take a look at how congested the highways used to transport coal are Weren’t the corruption cases at the Ministry of Railways also related to the approval process for coal transport cars in the railway system?
Coal gasification is primarily a strategic consideration; China is a country with limited oil reserves but abundant coal, and processes such as coal-to-oil production are also based on strategic considerations. At present, such projects incur losses unless international crude oil prices rise significantly. When South Africa was under sanctions and faced an oil embargo, it relied on its own coal-to-oil technology, which is why South Africa has advanced skills in coal gasification
Gases are easier to transport than solids (the transportation cost is relatively low)； Industrial coal use is more environmentally friendly than domestic coal use (industrial sectors have relatively lower costs for controlling pollutant emissions, and supervision is also easier) ； Diversifying the energy structure is beneficial to China’s energy security; coal-to-gas conversion, as a useful supplement to natural gas production in China, contributes to enhancing the country’s energy security ； Developing new processes contributes to the technical accumulation of related industries, providing a knowledge base for industrial innovation.
Another point is that in coal-producing areas, there is an excess of coal that cannot be sold, and there is no place to store it; coal-to-gas conversion can help consume some of this coal
1. Chemical reactions are difficult to occur within solids, with few exceptions. For example, combustion also occurs on the surface of solids; similarly, processes such as carburizing and nitriding also take place on the surface of solids. The reason is simple: the atoms and molecules in a solid are fixed in their respective positions and cannot move freely, so there are no targets or conditions for a reaction to occur. Therefore, it is very difficult to remove contaminants from within the solid, and it is simply not feasible from a cost perspective. 2. The transportation or movement of solids is more difficult compared to fluids, and they are not as convenient to use as fluids. 3. The difficulty of automated control varies greatly. Fluids can be measured with high precision, while the measurement accuracy for solids is several orders of magnitude lower.
Gasification is carried out as a step toward producing products such as methanol; after gasification, gases including carbon monoxide and hydrogen are generated, which are known as useful gases. Then, various methods are used to remove unwanted impurities from these gases, and the ratio of carbon monoxide to hydrogen in the gases is adjusted through reforming, before the synthesis reaction takes place. In other words, coal can only be used as a raw material for the chemical industry after it has been gasified. Although the utilization rate of carbon is very low and a large portion of it ends up as carbon dioxide emissions, it remains profitable at present; that’s why there are many coal chemical projects
I believe that any discussion of an issue is inseparable from the market; without the rigid demand of the market, even the best technologies are of no use. The gas produced through coal gasification can be used in metal smelting and other applications, and its cost is lower than that of natural gas. With such market demand, coal gasification becomes meaningful, and this is the main reason for carrying it out.
http://www.coalchem.org.cn/dujia/html/800214/162860.html What are the opinions of the forum moderator on this article?