RU2637551C2 - Method of thermal coal enrichment - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: method is thermal-oxidative processing of coal in that the carbonation is carried crushed coal or coal briquettes with particle size 60 mm in the Layers machine shaft type with a reversed blast air with a maximum temperature of 500-750°C with pulsating giving of the oxidant.

EFFECT: possibility of obtaining from the coal-rich particulate solid fuel with high calorific value and a controlled content of residual volatiles, as well as reducing energy costs.

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Description

The invention relates to the field of coal processing, in particular to the production of high-calorie solid fuel for metallurgical and energy purposes, suitable for transportation over long distances, as well as associated combustible gas.

A number of methods and devices are known for heat treatment of coal using the layered coking technique designed to produce heat-treated solid fuel (semi-coke). The closest to the proposed coal processing process design is a method for producing metallurgical medium-temperature coke (Eurasian patent No. 007799, priority 02.27.2007; RF patent No. 20144883, priority 30.06.1994). The closest product quality is the method for producing semi-coke from brown coal in vortex chambers, proposed by the Institute of Combustible Minerals (RF patent 2113451, priority 20.06.1998).

The method using the layered coking technique involves igniting the coal layer from the side opposite to the air supply, as a result of which, with certain parameters of the blast, a reverse heat wave is generated, which is shifted towards the air flow. When a heat wave passes through a layer, coal is subsequently subjected to heating, drying, and pyrolysis, thus turning into coke. The vapor-gas mixture of drying and pyrolysis products, as well as part of the coke, react with the oxygen of the air until it is completely exhausted, forming a narrow combustion zone, within which the temperature is reached from 750 to 900 ° C. Further along the path, the hot combustion products (CO ₂ and H ₂ O) are reduced on coke to carbon monoxide and hydrogen. Combustible gas is removed from the apparatus for subsequent processing and use. The carbon residue formed after thermal oxidative treatment is classified as medium temperature coke.

The disadvantages of this method and device are the high operating temperatures and high speed of the process, which negatively affects the strength of the carbon residue (carbonizate) obtained from coals of a low degree of metamorphism (namely, coals of grades 3B and D).

The method (RF patent No. 2113451) with obtaining the product closest in quality, involves grinding coal to a particle size of 25 mm, drying it at 80-120 ° C in a vortex chamber in a gas coolant stream to a residual moisture content of 10-15%, and then obtaining the target product in a vortex chamber at 380-420 ° С with further thermo-pelletizing in a roller press.

The main disadvantages of this method include the small fractional composition of coal supplied for processing (0-25 mm), which requires increased energy costs for grinding the original coal, as well as the small fractional composition of the resulting coke, which essentially eliminates the possibility of using the resulting coke as smokeless municipal fuel for fired furnaces, and also limits its use in metallurgy, where classes 10-2 are widely used as fuel and carbon reducing agent 5 mm, 25-40 mm and larger, and the class 0-10 mm has limited use only as an agglomeration or process fuel. Another disadvantage of this method is the need for briquetting, which, in turn, increases the cost of the finished product.

The objective of the present invention is to eliminate the above disadvantages of known methods and devices in order to reduce the energy cost of grinding the original coal, to obtain lumpy (class 10 mm and larger) carbonizate - high-calorie solid fuel that meets the technical requirements for carbon reducing agents for metallurgy and is suitable for use in as smokeless household and energy fuel.

The technical result of the invention is the production of lumpy coal (10 mm and larger) carbonizate with increased heat of combustion and an adjustable content of residual volatile substances that meets the requirements for carbon reducing agents for metallurgy and is suitable for use as smokeless municipal fuel for fired stoves, energy fuel, reducing energy costs for grinding the source coal and eliminating the stage of briquetting, as well as the production of generator g basics, the use of which allows to reduce the cost of the resulting carbonizate and ensure environmentally friendly production of thermal energy.

The technical result is achieved by heat-oxidizing treatment of coal or coal briquettes with a grain size of up to 60 mm in a layered apparatus with reverse air blasting at maximum temperatures of 500-750 ° C, while air is supplied to the apparatus periodically, which ensures, at the same time, maintaining the required heating rate of the layer, the following before the heat wave, as well as achieving the required maximum temperature, which in turn determines the value of the residual yield of volatile substances of the finished product. Generator gas generated during carbonization is used to generate thermal energy.

The invention is illustrated in the drawing, which shows a layered apparatus with reversed air blast.

To achieve a technical result, the method is as follows. Crushed coal 1 with a grain size of up to 60 mm is loaded into the mine layer apparatus through the loading hatch. The upper layer of coal is preheated to a temperature above the ignition temperature of coal from the heating panel 2. After heating to the designated temperature, the ignition device is turned off. Under the gas distribution grill at the bottom of the shaft, with the help of compressor 3, air is supplied with a specific flow rate of 20-60 m ³ / (m ² ⋅h), the flow rate is regulated using a flow meter 4. After that, the parameters of the pulsating air supply with a flow time of 20 to 60 seconds are set and the air cut-off time from 60 to 180 seconds, depending on the properties of the resulting product. To ensure a pulsating supply of an oxidizing agent, a time relay is used installed in the electric circuit of the blower device. Thus, a reverse heat wave is formed, which is shifted towards the flow of the oxidizing agent, leaving behind a layer of hot product. Coal during the passage of a heat wave is sequentially subjected to heating, drying and pyrolysis. The temperature of coal is determined using thermocouples 5. Combustible pyrolysis products are burned in oxygen in the air to form carbon dioxide and water vapor, which are then reduced on the hot surface of the coke to carbon monoxide and hydrogen, thus forming combustible gas 6. The gas composition is determined using gas analyzer 7.

After the heat wave reaches the gas distribution grid level, the process is completed, the oxidant supply is stopped.

In examples illustrating the method, a shaft-type apparatus with an internal diameter of 300 mm and a height of 1500 mm was used.

Example 1

МДж/кг, прочность на раздавливание 16,6 МПа и следующий технический и элементный состав:The raw material used was ZB brand coal (Kansk-Achinsky coal basin, Bolshesyrskoye deposit) having a specific heat of combustion per working mass

MJ / kg, crush strength 16.6 MPa and the following technical and elemental composition:

A ^d = 5% V ^daf = 45.9% C ^daf = 74.5% H ^daf = 5.2% N ^daf = 0.8% O ^daf = 19.2% S ^daf = 0.3%

Particle Size: 15-40 mm.

Loading device: 58 kg of coal.

Specific air consumption: 60 m ³ / (m ² ⋅h).

Air supply period: 20 seconds.

The stop period of the blowing device: 170 seconds.

The maximum temperature in the layered apparatus is 580-670 ° C.

The yield of coke residue is 55% by weight of the initial coal.

МДж/кг и следующий технический и элементный состав:The obtained coke residue has a crushing strength of 8-10 MPa, which meets the conditions of transportation and storage, has a specific heat of combustion per working mass

MJ / kg and the following technical and elemental composition:

A ^d = 7.4% V ^daf = 15.9% C ^daf = 88.6% H ^daf = 3.3% N ^daf = 0.8% O ^daf = 7, l% S ^daf = 0.17%.

The resulting product is a high-calorie solid fuel (specific heat of combustion is 44.1% higher than that of the original coal) having a satisfactory strength for storage and transportation.

Example 2

МДж/кг, прочность на раздавливание 28 МПа и следующий технический и элементный состав:As a raw material, brand D coal was used (the Mokhovsky open pit of the Kuznetsk coal basin) having a specific heat of combustion per working mass

MJ / kg, crushing strength 28 MPa and the following technical and elemental composition:

A ^d = 5.5% V ^daf = 46.2% C ^daf = 78.0% H ^daf = 5.5% N ^daf = 1.7% O ^daf = 14.5% S ^daf = 0.35%.

Particle Size: 15-40 mm.

Loading device: 55 kg of coal.

Specific air consumption: 40 m ³ / (m ² ⋅h).

Air supply period: 25 seconds.

The stop period of the blowing device: 160 seconds.

The maximum temperature in the layered apparatus is 630-700 ° С.

The yield of coke residue is 58% by weight of the source coal.

МДж/кг и следующий технический и элементный состав:The resulting coke residue has a crushing strength of 9-12 MPa, which meets the conditions of transportation and storage, has a specific heat of combustion per working mass

MJ / kg and the following technical and elemental composition:

; A^d=9,1%; V^daf=14,3%; C^daf=87,4%; S^daf=0,18%.

; A ^d = 9.1%; V ^daf = 14.3%; C ^daf = 87.4%; S ^daf = 0.18%.

The resulting product is a high-calorie solid fuel (specific heat of combustion is 23% higher than that of the original coal) having a satisfactory strength for storage and transportation.

Example 3

МДж/кг, прочность на раздавливание 26 МПа и следующий технический и элементный состав:

; A^d=11,3%; V^daf=35,6%; C^daf=51,4%; S^daf=0,25%.As a raw material, grade D coal was used (Karakansky-Yuzhny open pit of the Kuznetsk coal basin) having a specific heat of combustion per working mass

MJ / kg, crushing strength 26 MPa and the following technical and elemental composition:

; A ^d = 11.3%; V ^daf = 35.6%; C ^daf = 51.4%; S ^daf = 0.25%.

Particle Size: 15-40 mm.

Loading device: 56 kg of coal.

Specific air consumption: 30 m ³ / (m ² ⋅h).

Air supply period: 40 seconds.

The stop period of the blowing device: 150 seconds.

The maximum temperature in the layered apparatus is 670-750 ° С.

The yield of coke residue is 62% by weight of the initial coal.

МДж/кг и следующий технический состав:The resulting coke residue has a crushing strength of 15-20 MPa, which meets the conditions of transportation and storage, has a specific heat of combustion per working mass

MJ / kg and the following technical composition:

; A^d=18,1%; V^daf=16,4%.

; A ^d = 18.1%; V ^daf = 16.4%.

The resulting product is a high-calorie solid fuel (specific heat of combustion is 33.5% higher than that of the original coal) having a high strength that meets the conditions of storage and transportation.

Thus, the proposed method allows to obtain lumpy coal (class 10 mm and larger) carbonizate - high-calorie solid fuel that meets the technical requirements for carbon reducing agents for metallurgy and is suitable for use as smokeless communal and energy fuel.

Claims (1)

A method of thermo-oxidative processing of coal to produce solid fuel and combustible gas, characterized in that the carbonization of crushed coal or coal briquettes with a particle size of up to 60 mm is carried out in a mine-type layered apparatus with reverse air blasting at a maximum temperature of 500 to 750 ° C at a specific flow rate air 20-60 m ³ / (m ² ⋅ h), using a pulsating air supply with an air supply time of 20 to 60 seconds and an air supply cut-off time of 60 to 180 seconds, depending on the properties of the resulting product.

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