Introduction to indirect liquefaction of coal, what is the reaction of liquefaction of coal

The liquefaction of coal is a chemical change.

Coal liquefaction is an advanced clean coal technology that converts solid coal into liquid fuels, chemical raw materials and products through chemical processing. Including many reactions: according to different processing routes, coal liquefaction can be divided into two categories: direct liquefaction and indirect liquefaction.

Direct liquefaction means carbonization and hydrogenation.

The carbonization process is to isolate the coal from air and heat it to produce coke, gas and coal tar. Coal tar is desulphurized and hydrogenated to produce liquid fuel. However, the liquid fuel produced by this method is difficult to be applied to internal combustion engines without further processing, so it is not very practical.

Hydrogenation process. : The liquefaction of coal by hydrogenation process was invented in Germany in the 20s of the 20th century, mixing pulverized coal and heavy oil, under the action of a catalyst, in 400

c to 5000

c temperature and reaction under conditions from 20 to 70 MPa: nc

n+h2→cnh2n+

Indirect conversion process.

Indirect liquefaction is to gasify coal first to produce water gas, and then synthesize fuels such as ethane and ethanol, and can also further synthesize fuel oil.

Chemical change, the liquefaction of coal is divided into two types: direct liquefaction is to let coal and hydrogen be added under certain conditions, indirect liquefaction is to first let coal and water react to generate CO and hydrogen, and then let CO and hydrogen react to form methanol and other fuels.

Direct liquefaction of coal (advantages: simple steps, low cost).

Direct coal liquefaction is the direct conversion of coal into a liquid product. Its processes mainly include EXXON hydrogen supply solvent method (EDS), hydrogen-coal method, etc. The EDS method is that the coal slurry is mixed with hydrogen in a circulating hydrogen supply solvent, and the solvent first passes through the catalytic converter to pick up the hydrogen atoms, and then through the liquefaction reactor, the hydrogen atoms are released to decompose the coal; The hydrogen-coal method uses an ebullated-bed reactor to convert coal into liquid fuel by direct hydrogenation.

The coal-oil co-refining process developed in the 80s of the 20th century has improved the economy of coal liquefaction. Coal-oil co-refining is the mixing of coal and residue into oil-coal slurry, which is then refined into liquid fuel. Since the residue contains most or all of the hydrogen required for the coal conversion process, the cost can be significantly reduced.

Coal indirect liquefaction (advantages: low requirements for raw materials, product ***) indirect liquefaction first reacts the raw coal with oxygen and water vapor to gasify all the coal, and the crude gas prepared is transformed into clean syngas (CO+H2) through transformation, desulfurization and decarburization, and the syngas undergoes a synthesis reaction under the action of a catalyst to generate hydrocarbons, which can be further processed to produce gasoline, diesel and LPG and other products.

In the process of coal liquefaction, harmful elements such as sulfur and inorganic minerals (converted into ash after combustion) contained in coal can be removed, and sulfur can also be obtained in the form of sulfur, and the quality of liquid products is better than that of general petroleum products.

Direct coal liquefaction is an important coal chemical conversion technology, the basic principle of which is to directly convert coal into liquid fuel under high temperature and high pressure, which has the important significance of comprehensive utilization of coal resources and improvement of energy utilization efficiency. The chemical reaction of direct liquefaction of coal mainly includes the following two steps:

1) Hydrogenation Reaction Equation:

C H2 Ch4, C 2H2 Ch4 H2O, C 3H2 Ch4 2H2O, 2) Cleavage reaction equation.

<> CNHM (N m 4)H2 (N 2)CH4 (M 2)C2H6 (N 2-M 4)CN-2H2N,CNHM (N M 2)H2 NCH4 (M 2)C2H6, the above reactions can be summarized into the following equation for direct liquefaction of coal.

Total Equation Sakura Triver:

nc＋(2n+m)h2→nch4＋(n+m/2)c2h6＋(n-m/2)cn-2h2n。

C, H2 and CH4 represent coal, hydrogen and methane, CNHM represents the chemical formula of coal, and C2H6 represents ethane. In the actual industrial process, it is also necessary to consider the reaction conditions, reaction catalysts and other factors to make the reaction process as efficient, safe and economical as possible, and ensure product quality and output.

The liquefaction equation for coal: CO+2H2=CH3OH (methanol).

The industrial analysis of coal is the main index to understand the characteristics of coal quality, and it is also the basic basis for evaluating coal quality. Usually, the moisture, ash, and volatile content of coal are directly measured, while the fixed carbon is calculated by differential subtraction. Broadly speaking, the industrial analysis of coal also includes the determination of the total sulfur content and calorific capacity of coal, also known as the whole industrial analysis of coal.

According to the analysis results, we can roughly understand the content of organic matter in coal and the level of calorific energy, so as to preliminarily judge the type of coal, processing and utilization effect and industrial use, and calculate the calorific value of coal and the yield of coking products according to the industrial analysis data. The industrial analysis of coal is mainly used in the coal production, mining and commercial sectors and various users of coal, such as coking plants, power plants, chemical plants, etc.

Moisture of coal: 1. The moisture of coal is one of the most basic indicators in coal pricing. The moisture of coal directly affects the use, transportation and storage of coal.

The moisture of coal increases, the useful components in coal are relatively reduced, and the moisture becomes steam to absorb heat when burning, thus reducing the calorific value of coal. The moisture content of the coal increases, and it also increases the ineffective transportation, which rises early and late and brings difficulties to unloading. Especially in cold areas in winter, frozen cars often occur, which affects unloading, production, and wagon turnover, which aggravates the tension of transportation.

2. The moisture of coal is also easy to cause coal to stick to the silo and reduce the capacity of the coal bunker, and even cause silo plugging accidents. With the increase of mine mining depth, the development of mining mechanization and the strengthening of underground safety production, as well as the implementation of measures such as dew sprinkling, coal seam water injection, and comprehensive dust prevention, the moisture of raw coal has shown an increasing trend.

To this end, in addition to formulating measures to reduce the moisture content of coal in the mining design and in all aspects of coal mining, tunneling, ventilation and transportation in the mining process, coal mines should also take measures to reduce the moisture content of coal in the surface processing of coal.