The development direction of coal as raw material for coal chemical industry

Coal ash composition: SiO2, Al2O3, TiO2, Fe2O3, CaO, MgO, SO3, K2O,

Na2O, P2O5, are represented by these components, but they are not real components.

Ash fusibility temperature: DT, ST, HT, FT

Al2O3, TiO2 play the role of skeleton, Fe2O3 plays the role of flux.

The effect of SiO2 and CaO on the fusibility of coal ash is not necessarily.

The composition of coal ash can tell you a lot of information, including the place of origin, the type of coal, and the sulfur in the coal

Content, such as Fe2O3 content is high, it is possible that the sulfur content in coal is high. K2O, Na2O,

P2O5, also an important indicator, is getting more and more attention.Fourth, the quality of raw coal

4.1 Direction of coal quality research

Research direction of coal quality: reactivity, grillability, ash fusibility, known as the "new three properties"

(1) Coal quality level

Generally refers to the quality of coal is good or bad, conventional coal quality indicators are water, ash, sulfur, heat

Volume, cohesiveness.

(2) The main coal quality indicators that need to be considered in coal coking

Adhesion and coking property.

(3) The main coal quality indicators that need to be considered in modern coal chemical industry (gasification as the leader)

Reactivity, ash fusibility, grindability (indirectly can indicate the strength of lump coal)

(4) Coal combustion power generation: reactivity, grindability, coal ash melting property

4.2 Types of chemical raw coal

From a professional point of view, the chemical raw material coal includes:

Coal for coking: metallurgical coke;

Raw coal for pyrolysis: orchid carbon, pyrolysis oil extraction;

Raw material for direct liquefaction coal: direct liquefaction to oil;

Gasification of raw coal: industrial and civil gas, chemical fertilizer (synthetic ammonia), coal to natural

Gas, coal to methanol, coal to synthetic oil, coal to hydrogen, coal to olefin, coal to ethylene glycol, coal

Aromatic hydrocarbon production;

Raw coal for carbon materials: activated carbon, filter, etc.;

Reducing agent for raw coal: low ash, low sulfur cheap bituminous coal.

4.3 Main indicators of high-quality chemical raw materials coal

Coking coal: strong adhesion, low ash, low sulfur;

Raw coal for pyrolysis: high oil content, low ash, low sulfur;

Raw coal for direct liquefaction: low ash, less inertinite component, high H content (high oil content), sulfur

Points can be high or low;

Coal for gasification: in principle, there are no strict requirements for sulfur content, because there are sulfur recovery devices,

Sulfur recovery also has some benefits. A ton of sulfur is more expensive than a ton of coal.

Solid slagging fixed bed: high strength of lump coal, no adhesion, high temperature of coal ash melting;

Liquid slagging fixed bed: high strength of lump coal, no adhesion, low temperature of coal ash melting;

Liquid slag-discharging coal water slurry airflow bed: must be fine grain, low ash, ash melting temperature is low;

Liquid slagging dry pulverized coal airflow bed: requirements are not too strict.

4.4 High-quality chemical raw material coal is an inevitable requirement for the healthy development of coal chemical industry

For cleaned coal for coking: the society has reached a consensus that it must be high-quality and economical

Significant.

For activated carbon, reducing agents, etc. : high-quality raw materials must be used, otherwise it cannot be done.

Due to the small distribution and small scale of direct liquefaction, the selection of raw coal is more careful.

However, there are still some misunderstandings about the quality of coal for gasification: it is believed that high-quality coal is of course used

Good, but the cost is high and the overall economic benefits are not obvious. Not so much.

4.5 Application of coal water slurry

Coal water slurry (CWM) is a type developed after the world oil crisis in the 1970s

A new, low-pollution, coal-based clean fluid fuel with coal instead of oil, it is composed of about 70% coal,

About 30% of water and about 1% of chemical additives are made through a certain processing technology

Coal and water mixture.

Coal water slurry not only maintains the original physical and chemical properties of coal, but also has good properties like oil

Liquidity and stability.

Coal water slurry can be pumped, atomized and stabilized ignition combustion, it replaces heavy oil combustion, with

High combustion efficiency, low emission of pollutants (SO2, NOx), about 2t coal water slurry instead of 1t fuel.

It can also be used as gasification raw materials for ammonia synthesis, methanol synthesis, urea synthesis and other chemical fields.

Concentration: the solid content of coal water slurry %, the concentration is large, the heat is large, but the viscosity is increased, which is unfavorable

For transportation and combustion. The general concentration is between 58% and 75%.

Rheology: Factors that affect the characteristics of storage, transportation and atomizing combustion. Static, want to have more

Large viscosity to prevent precipitation. Dynamic, hope to have a low viscosity, easy to pump and atomized combustion

Burn.

Stability: the precipitate can be divided into hard precipitate and soft precipitate, and the coal slurry may be restored by stirring