Post Date:5,Dec,2022
The so-called coal-water slurry refers to a slurry made of 70% pulverized coal, 29% water and 1% chemical additives after stirring. It is a fluid fuel that can be pumped and misted like fuel oil. It can be transported and stored over long distances, and its calorific value is equivalent to half of fuel oil. It has been used in transformed ordinary oil-fired boilers, cyclone furnaces, and even chain-type quick-loading furnaces. Compared with coal gasification or liquefaction, coal-water slurry processing method is simple, the investment is much less, and the cost is also low, so since it was developed in the mid-1970s, it has attracted the attention of many countries. my country is a big coal-producing country. It has invested more in this area and has gained rich experience. Now it is even possible to make high-concentration coal-water slurry from the coal powder produced by coal washing.
The chemical additives of coal-water slurry actually include dispersants, stabilizers, defoamers and corrosives, but generally refer to two categories of dispersants and stabilizers. The role of the additive is: on the one hand, the pulverized coal can be uniformly dispersed in the water medium in the form of a single particle, and at the same time, it is required to form a hydration film on the surface of the particle, so that the coal water slurry has a certain viscosity and fluidity;
On the one hand, the coal-water slurry has a certain stability to prevent the precipitation of pulverized coal particles and the formation of crusting. The three elements that high-quality CWS should have are high concentration, long stability period and good fluidity. There are two keys to preparing high-quality coal-water slurry: one is good coal quality and uniform distribution of coal powder particle size, and the other is good chemical additives. Generally speaking, coal quality and coal powder particle size are relatively stable, and it is the additives that play a role.
In order to reduce the production cost of coal-water slurry, in recent years, some countries have attached great importance to the research and application of humic acid and lignin as additives, which can produce composite additives with both dispersant and stabilizer functions.
Post time: Dec-05-2022
