Current Status of Activated Carbon Used in Water Plants in my country

There are many kinds of activated carbon products, which can be divided into wood activated carbon, fruit shell activated carbon, coal activated carbon, petroleum coke activated carbon and other activated carbons according to the properties of raw materials. The industrial layout characteristics of my country's activated carbon industry are as follows: coal-based activated carbon manufacturers are mainly concentrated in Shanxi and Ningxia provinces. At present, the output of coal-based activated carbon in these two bases accounts for about 90% of the national coal-based activated carbon output; Mainly; the production of wood activated carbon is mainly concentrated in Fujian, Jiangxi, southern Zhejiang and Northeast China. Because coal-based activated carbon has the advantages of low cost, convenient production and processing, and a wide range of raw material sources, most of the coal-based carbons used in the operation of drinking water treatment processes in my country are coal-based carbons, while the application of wood-based charcoal and nutshell charcoal in actual production is relatively low. few.

Coal activated carbon can be divided into granular activated carbon and powder activated carbon according to the shape. Granular activated carbon is mainly used for advanced treatment of drinking water plants. The treatment processes include adsorption activated carbon technology, biological activated carbon technology, combined use of ozone activated carbon, and combined use of granular activated carbon and membrane treatment technology. At present, coal-based granular activated carbon used in water plants in my country mainly includes 1.5 mm cylindrical activated carbon, raw coal crushed activated carbon, briquette (tablet) and cylindrical crushed activated carbon.

Different from the other two types of coal granular activated carbon, briquette (tablet) and cylindrical crushed activated carbon are not products of a single type of coal, but are made of blended coal through grinding, forming, carbonization, activation, crushing and screening. That is, coal types with different pores are mixed and matched according to a certain proportion, and some chemical reagents that can change the distribution of pore structure may even be added. This preparation process, on the one hand, rolls out the rough surface, which improves the film-forming performance of the activated carbon; The filterability of the filter layer reduces the risk of biological leakage. This not only solves the problem of performance limitations caused by the singleness of raw materials, but also greatly improves the product performance of coal-based activated carbon. After 2010, briquette (sheet) and cylindrical crushed activated carbon have been widely used by many large water plants in China, such as those in Wuxi, Shanghai, Beijing, Zhengzhou, Jinan, Suzhou, Changchun, Jiaxing and other places. In 2013, the survey results of the advanced treatment projects built and under construction in the whole country showed that among the 94 advanced treatment projects, 22 advanced water treatment plants used columnar activated carbon, 14 used raw coal crushed carbon, and 14 used briquettes. There are 31 kinds of (sheets) and cylindrical crushed activated carbons. Powdered activated carbon is mainly used in emergency dosing of water sources for sudden pollution and in combination with other processes, such as coagulants, membrane treatment processes or diatomite combined use and other technologies. Powdered activated carbon for drinking water treatment can usually be divided into two specifications: 200 mesh and 325 mesh. Powdered activated carbon is obtained by grinding the undersize of various activated carbons. Among them, the powdered activated carbon prepared from briquette (tablet) crushed carbon, cylindrical crushed carbon and bituminous activated carbon is more efficient than cylindrical activated carbon and The powdered activated carbon obtained by activating anthracite has higher iodine value and methylene blue value.

Many researchers have conducted comparative studies on activated carbon with different production raw materials, but there are great differences between the research results, which may be caused by the different product quality of activated carbon manufacturers and the difference in water quality between different regions. When selecting carbon species, not only must take into account the indicators, but also carry out preliminary test research on local water sources. According to the test results and actual process requirements, select the appropriate activated carbon to ensure the expected treatment effect of drinking water.