Chemical industry development in the context of carbon neutrality

In terms of carbon emissions per unit income, coal chemical products such as coal-to-methanol, coal-to-dimethyl ether, coal-to-natural gas, and synthetic ammonia have the highest carbon emissions per unit income. The industrial processes of coal to ethylene glycol and nitric acid have higher carbon emission per unit income. Carbon black, calcium carbide, alumina and soda ash have higher carbon emission per unit income. Titanium dioxide, propylene oxide and other products have lower carbon emissions per unit income.

From the point of view of total emission intensity, all kinds of chemical products we statistics are basically distributed along the diagonal in the figure, individual products offset larger, some chemical products with smaller output, often higher prices, thus lower carbon emissions per unit income, such as titanium dioxide; On the contrary, some chemical products with larger output tend to have lower prices and thus higher carbon emissions per unit income, such as coal to methanol. Some chemical products with higher output and higher carbon emission intensity have more room to reduce emissions in the future.

2.3.3. Taking coal to methanol as an example, the carbon emission of chemical products in the industrial process is lower than the theoretical value

Coal chemical industry is a characteristic chemical sub-industry in China. Most of methanol production uses coal as raw material, and carbon emissions are mainly generated in sulfur recovery units. Raw coal is usually fed fresh gas into the methanol synthesis unit after gasification and multiple conversion processes to produce methanol. In this process, the purification process of the conversion gas will produce carbon dioxide gas, part of which is used as a raw material to participate in the synthesis of methanol, and most of the other is discharged as an emission gas.

From the calculation of actual production projects, it can be seen that the carbon emission per unit output of the industrial process of coal-to-methanol is lower than the theoretical value calculated according to the chemical reaction formula. There are several ways to calculate the carbon emission of chemical products. One is to calculate the carbon emission theoretically according to the physical and chemical properties of the products and the chemical reaction equation. The second is to monitor material input and output in actual production projects, prepare material balance sheets and calculate carbon emissions.

The carbon emission data calculated according to molecular formula and chemical reaction formula is the theoretical emission limit, because the original materials can not be converted into products according to the ideal situation in the actual production process; Carbon may not be completely expelled as a gas; The carbon oxygenation rate of the material is not 100%.