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

1. Opportunities for the re-development of coal chemical industry

1.1 The importance of coal chemical industry is emphasized again

The characteristics of China's coal-based energy resource endowment determine the current and future periods

Coal is still an important basic energy in the energy supply system, which plays the role of energy pressure.

On February 28, 2022, the National Energy Administration once again proposed to "continue to develop the clean use of coal.

Technology is listed as the key direction of national science and technology development ", including clean coal power technology and clean coal transformation

Two broad categories of technology. However, the clean transformation of coal in China is still in the initial stage.

The state attaches great importance to the development of coal-to-oil and gas industry. After years of pilot demonstrations, a batch of them by me

Demonstration projects independently developed, designed and constructed by the State have been completed and put into operation, and the industry has formed a certain scale.

Breakthroughs in technology and equipment have been achieved, the level of operation has been continuously improved, and the overall level has reached the international leading level

Guaranteeing national energy security in extreme circumstances provides a reliable path with large-scale development

The conditions.

1.2 Clear the direction of coal chemical industry

It is stressed that the coal chemical industry has great potential and great prospects, and it is necessary to improve the use of coal as chemical raw materials

Comprehensive utilization of efficiency, promote the high-end, diversified, low-carbon development of the coal chemical industry, and add

Strong scientific and technological innovation as the most urgent task, speed up key core technology research, and actively develop coal-based

Special fuels, coal-based biodegradable materials, etc.

The Central Economic Work Conference from December 8 to 12, 2021 proposed that it should be correctly understood and grasped

To reach the peak of carbon and carbon neutrality, scientific investigation is required, and new renewable energy and raw material energy use are not included in the energy

Total source consumption control, create conditions to achieve energy consumption "double control" to the total amount and intensity of carbon emissions as soon as possible

"Dual control" transition.

1.3 The concept of "raw coal" is proposed

"Energy use of raw materials"

Refers to oil, coal, natural gas and other energy products are not used as fuel

Force is used, and the part used as a raw material for production.

On December 11, 2022, Ning Jizhe, Director of the National Bureau of Statistics, attended the "2021-2022 Conference.

As explained at the National Economic Annual Meeting, raw material energy is generally only 20%CO2 emissions, and 80% is converted into

Raw materials, so statistically they have to be counted separately. So the concept of raw coal came into being.

As the name suggests, raw coal refers to the coal used as a raw material, and the end product includes: coke

Chemical fertilizer, methanol, ethylene glycol, olefin, oil and gas products, material products, activated carbon, etc.

Under the policy premise of "raw material energy use is not included in the total energy consumption control", it must be correct

Raw coal and fuel coal are distinguished, and respectively named and counted.

The work should begin at the raw coal supply end.

1.4 Development trend of coal chemical industry

The 14th Five-Year Plan for National Economic and Social Development of the People's Republic of China and 2035

The Outline of the Vision Goal proposes to steadily promote the construction of the coal-to-oil and gas strategic base, establish production capacity and

Strategic requirements for technology reserves.

Improve the comprehensive utilization efficiency of coal as a raw material, and promote the high-end and diversified coal chemical industry

Chemical and low-carbon development, and actively develop coal-based special fuels and coal-based biodegradable materials.

On May 30, 2022, Liu He attended the 16th Academician Conference of the Chinese Academy of Engineering and stressed:

Pay attention to coal to oil to gas, based on the resource endowment to improve the level of energy security. Improve resource exploration and

Development level, pay attention to the research and development of coal to oil to gas and other technologies, while promoting green and efficient new energy

Develop.

1.5 The coal chemical industry must develop with high quality under the background of "dual carbon"

The goal of "double carbon" is one of the basic national policies of our country. CO2 emissions should be achieved by 2030

Peak, working towards carbon neutrality by 2060.

In 2021, China's raw coal production will reach 4.07 billion tons, an increase of 4.7% and an increase of 5.6% over 2019.

China imported 320 million tons of coal, up 6.6% over the previous year. Total: 4.4 billion tons

Coal as a raw material can not only sequester carbon, but also provide rich oil and chemical products

It has effectively expanded the consumption and utilization space of coal.

Coal as a raw material should be developed to high-end products, continue to extend the industrial chain, and develop high performance

Can the product.

Special attention is paid to the coupling of "coal → coke → hydrogen energy + special materials".

High quality development should be manifested in:

(1) Production of high value-added, scarce, difficult to produce oil and natural gas products. For example:

Clean fuel (gas, liquid), high calorific value fuel (aviation kerosene), cold resistant fuel (military

Products), high-grade carbon-containing materials (battery negative carbon materials), etc.;

(2) High conversion rate, low energy consumption, low emissions (pollutants);

(3) CO2 centralized treatment and utilization, and CO2 concentration in the tail gas generated by the coal chemical process

The concentration of CO2 in the tail gas produced by coal power plants is much higher, which is easy to purify.

(4) Raw coal solves worries for the high-quality development of the coal industry, such as high-sulfur coal

Raw materials, low rank coal with high humic acid as soil amendment, etc.

High quality development should be manifested in:

(1) Production of high value-added, scarce, difficult to produce oil and natural gas products. For example:

Clean fuel (gas, liquid), high calorific value fuel (aviation kerosene), cold resistant fuel (military

Products), high-grade carbon-containing materials (battery negative carbon materials), etc.;

(2) High conversion rate, low energy consumption, low emissions (pollutants);

(3) CO2 centralized treatment and utilization, and CO2 concentration in the tail gas generated by the coal chemical process

The concentration of CO2 in the tail gas produced by coal power plants is much higher, which is easy to purify.

(4) Raw coal solves worries for the high-quality development of the coal industry, such as high-sulfur coal

Raw materials, low rank coal with high humic acid as soil amendment, etc.

1.7 Coal chemical industry is the guarantee for the diversification of clean energy supply in China

China has a large population and a complete range of industrial categories, which requires clean fuel oil and chemicals

They are all different, so we not only have to make our energy supply secure, we also have to make it special

Security of supply of energy and chemicals. Coal chemical products provide us with more choices.

For example: oil (polymethoxy-dimethyl ether) in cold and anoxic environment; Aerospace special

Special oil products; High clean oil products (indirect liquefied oil products contain almost no sulfur); And of course

Many chemicals with special functions.

Second, the status quo and problems of coal used in coal chemical industry in China

2.1 The characteristic and difficulty of coal chemical technology is that the coal quality is right

Any coal-related project, coal quality is the key to the success of the project, the benefit is good or bad

Quality is the right way, management is the right way."

The basic condition for the success of coal chemical project is that the coal quality must be right, generally speaking,

coal

"Coalification" is to effectively and economically "transform" coal, which is a technical engineering of coal workers

Characteristics and difficulties.

As far as the current situation is concerned, most coal chemical projects in China attach great importance to the research and evaluation of coal quality.

Basically can achieve the "coal quality"

The author has published an article "Standardization is the long-term healthy development of China's coal chemical industry.

Guarantee.

2.2 Common problems of coal used in coal chemical industry

The main problems of the wrong way are as follows:

① The understanding of the fusibility of coal ash is not clear, there is a vague understanding, and there is a fantasy about the flux;

(2) There is also a phenomenon of "setting the furnace type and then collecting coal";

(3) Research and evaluation of long-term stability of coal quality are not in place;

(4) There are no good countermeasures for special types of coal such as high potassium and sodium;

(5) There are misunderstandings about the content of coal tar that can be extracted;

⑥ The economy of lignite gasification is blindly optimistic.

The economic research of raw coal is insufficient, for example: the real coal price of lignite is not low, Changzhi

The coal price of lean coal and lean coal in the region is higher.

Third, the matching of coal quality and gasification technology

3.1 The matching of gasification technology and coal quality is the key to the selection of coal chemical technology:

(1) The reliability of long-term stable operation of the gasifier system; (Technology maturity)

(2) Long-term production safety (system safety level)

(3) Environmental protection of long-term production

(4) Long-term production efficiency (economy)

(5) Adaptability of coal quality and post-processing adaptability (applicability)

(6) Long-term stability of raw coal quality

The evaluation of these six key problems can judge whether the gasification technology is correct or not.

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

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

Complex uniform precipitation is called hard precipitation, and vice versa is soft precipitation.

Quality requirements: good rheological properties; Good stability and thixotropy; Reasonable granularity

Buttish.