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

3.2 The coal quality should be determined first and then the gasification technology should be selected

(1) Whether the coal can be economically gasification, in theory and principle, any coal can be gasification,

But the main coking coal, some characteristic coal is not suitable for gasification;

(2) the overall economy of the coal gasification, such as the coal price, the overall coal quality level;

(3) Matching with gasification technology: First look at the cohesiveness, coal ash melting, reactivity, can

Abrasive property, other special properties affecting gasification stability, etc.;

(4) long-term stability of coal quality;

(5) The design of coal quality (coal quality index) is scientific and reasonable.

The process of understanding the quality of coal is the process of choosing the gasification process, but it is only relatively good, not the best.

3.3 Should be familiar with the correlation between coal quality analysis indicators

The correlation between coal quality indicators is the basis of coal chemistry, should be familiar with, summarized as follows:

(1) Coal with strong cohesiveness has generally higher coal ash fusion, while coal with strong cohesiveness is only in principle

Coal water slurry can be gasification, but coal ash melting is high, so it is generally not suitable for gasification;

(2) The strength of good grindability coal is poor, and vice versa, such as the strength of coke is very good,

But the grainability is very poor, coke is only suitable for fixed bed gasification;

(3) The coal with low coal ash fusibility has higher potassium and sodium content and higher calcium, iron and magnesium content;

(4) The degree of coal metamorphism is high, the reactivity is poor, the gasification speed is slow, and the gasification temperature needs to be increased;

(5) The degree of coal metamorphism is low, the reactivity is good, the gasification speed is fast, and the gasification temperature can be appropriately reduced.

Oxygen consumption can be reduced;

(6) Lignite has low metamorphism, large moisture, easy weathering and low effective composition;

(7) Anthracite has a high degree of deterioration, no coal tar, no phenol-containing wastewater, and high effective composition

3.4 Should be familiar with the basic characteristics of gasifier and its connotation

A gasifier is very similar to a coal-fired boiler. Gasification temperature

The fluidized bed gasification temperature is about 950 ℃.

The gasification temperature of fixed bed (such as Lurgi furnace) is about 1200 ℃;

The gasification temperature of fixed bed (slag gasifier) is about 1400 ℃;

The gasification temperature of coal water slurry gasifier is about 1400 ℃.

The gasification temperature of dry pulverized coal gasifier is about 1600 ℃.

Low gasification temperature requires high reactivity of raw coal and low carbon conversion. E.g. Fluidized bed 90%

The following; High gasification temperature and high carbon conversion rate, such as Shell furnace carbon conversion rate ≥99%, Texaco water coal

Carbon conversion rate of pulp furnace ≥95%, Lurgi furnace: 88~96%.

The gasification temperature is high, the effective component (CO+H2) in the gas is high, and the gasification efficiency is high.

The gasification pressure has little effect on the gasification reaction, and has no requirement on the coal quality, but it has no effect on the coal behind

The effect of gas compression is great because of the high power consumption of gas compression.

The gasification pressure of Lurgi furnace is 2.5-4.0mpa;

The gasification pressure of slag gasifier is 2.5-4.0mpa;

The gasification pressure of coal water slurry gasifier is about 4.0~6.5, 8.7MPa;

The gasification pressure of dry coal gasifier is about 2.5~4.0, 6.5, 8.7MPa;

The pressure of fluidized bed gasifier is normal and low pressure (1MPa).

Methanol synthesis gas needs to reach 8.1MPa. Natural gas syngas requires 4MPa.

The gasification pressure has little effect on the gasification reaction, and has no requirement on the coal quality, but it has no effect on the coal behind

The effect of gas compression is great because of the high power consumption of gas compression.

The gasification pressure of Lurgi furnace is 2.5-4.0mpa;

The gasification pressure of slag gasifier is 2.5-4.0mpa;

The gasification pressure of coal water slurry gasifier is about 4.0~6.5, 8.7MPa;

The gasification pressure of dry coal gasifier is about 2.5~4.0, 6.5, 8.7MPa;

The pressure of fluidized bed gasifier is normal and low pressure (1MPa).

Methanol synthesis gas needs to reach 8.1MPa. Natural gas syngas requires 4MPa.

Coal water slurry gasifier process: all kinds of coal that can be slurry, ash melting point is low (≤1250 ℃);

Dry coal gasification process: in addition to strong bonding coal almost all coal, ash melting point should not be too high

(≤1350 ℃);

Fluidized bed gasification process: good reactivity, lignite, long flame coal and other non-cohesive young coal, ash

High melting point, but not very demanding.

No matter what kind of furnace type, there is almost no ideal gasification raw material coal, and the composition of coal is very complex.

3.6 Pay attention to the relationship between coal ash composition and coal ash fusibility