CN110240912B - Method for improving gasification coke reactivity by using alkaline composite additive - Google Patents

Abstract

A method for improving reactivity of gasified coke by using an alkaline composite additive comprises the steps of selecting raw materials of sodium carbonate, potassium carbonate and limestone, drying, crushing, stirring, uniformly mixing, carrying out dry grinding and calcining, and cooling to normal temperature to obtain the alkaline composite additive; then selecting blended coal, adding the alkaline composite additive into the blended coal according to a proportion, insulating air in a dry distillation furnace for heating, discharging the red hot furnace charge, and cooling to normal temperature through a coke quenching process to obtain reactive gasified coke containing the alkaline composite additive; the invention adopts the alkaline composite additive to be directly added into the blended coal, and prepares the gasified coke through high-temperature dry distillation, thereby improving the specific surface area and the reactivity of the gasified coke.

Description

Method for improving gasification coke reactivity by using alkaline composite additive

Technical Field

The invention relates to a method for improving gasification coke reactivity, in particular to an alkaline composite additive for improving gasification coke reactivity, a preparation method and application thereof.

Background

The gasified coke is used as a gasification raw material specially used for producing coal gas, is mainly applied to a pressurized or normal-pressure fixed bed gasification raw material to produce CO and H due to certain lumpiness and high hardness₂The synthetic coal gas which is the main component requires higher reactivity to improve the gasification efficiency compared with the index of the metallurgical coke, and has certain thermal strength and lumpiness to ensure the air permeability and prevent furnace collapse, and the gasification of the gasified coke has the following advantages of three aspects: firstly, the gasification process of the gasified coke does not produce high-concentration phenol-cyanogen wastewater, and can also treat part of coking wastewater to deeply treat residual liquid; secondly, the coke oven gas is partially or completely replaced, so that the emission of nitrogen oxides from a coke oven chimney can be reduced; thirdly, the coking and synthesis cost can be reduced by fusing with industries for preparing methanol, LNG and the like.

The gasification coke reactivity refers to the capability of the gasification coke to carry out chemical reaction with carbon dioxide, oxygen, water vapor and the like, the higher the gasification coke reactivity is, the more favorable the gasification coke reactivity is for full reaction with the oxygen, the carbon dioxide and the water vapor in a gasification furnace, the gasification efficiency is improved, the existing method for improving the gasification coke reactivity mainly comprises the step of adding more low-order bituminous coal, the coke reactivity can be improved, the utilization of low-order slack coal is increased, and the coking coal blending resource is enlarged.

There are few publications on improving reactivity of gasification coke, such as a method of producing high-strength and high-reactivity gasification coke by blending long-flame coal at a high ratio in publication No. CN107083265A, which prepares high-strength and high-reactivity gasification coke by tamping coking by adjusting the maximum addition amount of long-flame coal with a blended coal Y value > 10 and controlling the fineness of coal as fired, but improving reactivity of gasification coke only by blending low-rank coal has certain limitations and a limited range of improvement of reactivity.

The basic composite additive searched for improving gasification coke reactivity is not reported.

Disclosure of Invention

The invention aims to solve the specific technical problems of improving the reaction performance of the existing gasified coke and providing a method for improving the reactivity of the gasified coke by using an alkaline composite additive.

In order to achieve the above object, the present invention adopts the following technical solutions.

A method for improving gasification coke reactivity by using a basic composite additive is characterized by comprising the following steps: the method is carried out according to the following steps:

the method comprises the following steps of selecting raw materials: sodium carbonate Na₂CO₃More than or equal to 98 wt%; potassium carbonate K₂CO₃More than or equal to 96 wt%; CaO of limestone is more than or equal to 51 wt%;

drying the selected raw materials of sodium carbonate, potassium carbonate and limestone, and then respectively crushing until the granularity is less than or equal to 3 mm;

respectively weighing 20-40 parts of crushed raw materials of sodium carbonate, 20-30 parts of potassium carbonate and 30-50 parts of limestone in sequence by weight, mixing the raw materials together, stirring for 30-50 minutes, and uniformly mixing;

fourthly, the uniformly stirred and mixed mixture is ground in a dry mode to enable the particle size of the raw material to be smaller than or equal to 150 meshes, then the mixture is calcined for 1-2 hours at the temperature of 260-300 ℃, and the mixture is cooled to normal temperature to obtain the alkaline composite additive;

the quality indexes of the selected blended coal are as follows: FC_d≥55%，V_daf≥25%，A_dNot more than 20%, G value not less than 50, Y value not less than 10, S_t，d＜1.5%；

Sixthly, adding the alkaline composite additive into the blended coal according to the weight ratio of the alkaline composite additive to the blended coal of 0.5-4: 100, insulating air in a dry distillation furnace, heating to 900-.

Wherein the blended coal is formed by blending a plurality of weakly caking coal, gas coal, coking coal, fat coal, main coking coal, gas fat coal, non-caking coal and long flame coal.

According to the technical scheme, the alkaline composite additive is added to improve the pore structure of the gasified coke and further improve the reaction performance of the gasified coke, and the main characteristic of the alkaline composite additive is shown in the addition stage; the method is characterized in that the action mechanisms are different, the main process is divided into two steps, the first step is that alkali metal or alkaline earth metal ions are combined with carbon in the pyrolysis process to destroy the stable carbon-carbon bond structure, the pore forming effect is achieved, the pores of the gasified coke are developed, and the specific surface area is greatly improved; the second step is that alkali metal or alkaline earth metal ions act as a catalyst for the gasification reaction during the gasification process to form metal crystallites, which can improve the gasification reactivity.

Compared with the prior art, the method for improving the reactivity of the gasified coke by using the alkaline composite additive provided by the invention has the advantages that the additive is directly added into the blended coal, the gasified coke containing the alkaline composite additive is prepared by high-temperature dry distillation, and the specific surface area of the gasified coke is 20m from the original specific surface²The/g is increased to 110m²The reactivity increased from 50.0% to 80.0% of the original gasified coke.

The high-reactivity gasified coke is produced by adopting the existing tamping coking process technology, and the positive effect can be achieved by directly applying the technology without improving coke oven equipment and a coking process.

Detailed Description

The following further describes the embodiments of the present invention.

Example 1

The method for improving gasification coke reactivity by using the alkaline composite additive provided by the invention comprises the following specific implementation steps:

the method comprises the following steps of selecting raw materials: sodium carbonate Na₂CO₃98 wt%; potassium carbonate K₂CO₃99 wt%; 56% of limestone CaO, 56 wt%;

drying the selected raw materials of sodium carbonate, potassium carbonate and limestone, and then respectively crushing until the granularity is less than or equal to 3 mm;

respectively weighing 40kg of crushed sodium carbonate, 30kg of crushed potassium carbonate and 30kg of crushed limestone according to parts by weight, mixing the materials together, stirring for 30 minutes, and uniformly mixing;

fourthly, dry grinding the uniformly stirred mixture to enable the particle size of the raw materials to be smaller than or equal to 150 meshes (0.1 mm); then calcining for 1 hour at the temperature of 300 ℃, and cooling to normal temperature to obtain the alkaline composite additive;

the coal material fed into the furnace is blended coal formed by blending 30wt% of mahogany long flame coal, 20wt% of 1/3 coking coal, 20wt% of fat coal and 30wt% of gas coal; the quality indexes of the blended coal are as follows: v_daf31.2%，A_d13.1%，FC_d58.9%，S_t,d0.89 percent; the bonding index G =65, the Y value is 12.5, the fineness (≦ 3 mm) = 80.6%;

sixthly, adding the prepared alkaline composite additive into the blended coal according to the weight ratio of the alkaline composite additive to the blended coal of 0.5: 100, heating the mixture to 900 ℃ in a dry distillation furnace in an air-isolated mode, continuously heating the mixture for 24 hours, discharging the red hot furnace burden out of the furnace, and cooling the red hot furnace burden to normal temperature through a coke quenching process to obtain the gasified coke containing the alkaline composite additive.

Comparative example 1

Adding no additive into the blended coal, heating to 900 ℃ in a dry distillation furnace in an air-isolated mode, continuously heating for 24 hours, discharging the red hot furnace charge, cooling to normal temperature through a coke quenching process, and taking the obtained gasified coke as control coke.

The specific surface area and reactivity of the two coke groups were tested and the results are shown in table 1 below.

TABLE 1 gasification Coke reactivity and specific surface area comparison

Experimental groups	CRI（%）	Specific surface area (m)2/g）
			Contrast coke	50.0	15.8
Gasification coke added with composite additive	60.8	52.6

Example 2

The method for improving gasification coke reactivity by using the alkaline composite additive provided by the invention is implemented as follows:

the method comprises the following steps of selecting raw materials: sodium carbonate Na₂CO₃98.3 wt%; potassium carbonate K₂CO₃98.2 wt%; 54% of limestone CaO, 54 wt%;

drying the selected raw materials of sodium carbonate, potassium carbonate and limestone, and then respectively crushing until the granularity is less than or equal to 3 mm;

respectively weighing 35kg of crushed sodium carbonate, 22kg of crushed potassium carbonate and 35kg of crushed limestone according to parts by weight, mixing the materials together, stirring for 35 minutes, and uniformly mixing;

fourthly, dry grinding the uniformly stirred mixture to enable the particle size of the raw materials to be smaller than or equal to 150 meshes (0.1 mm); then calcining for 1.5 hours at 280 ℃, and cooling to normal temperature to obtain the alkaline composite additive;

the coal material fed into the furnace is blended coal formed by blending 35wt% of mahogany long flame coal, 20wt% of 1/3 coking coal, 25wt% of fat coal and 20wt% of gas coal; the quality indexes of the blended coal are as follows: v_daf31.5%，A_d12.9%，FC_d58.8%，S_t,d0.86 percent; the bonding index G =62, the Y value is 11.5, the fineness (≦ 3 mm) = 83.6%;

sixthly, adding an alkaline compound additive: adding the prepared alkaline composite additive into the blended coal at a weight ratio of 1: 100, insulating air in a dry distillation furnace, heating to 950 ℃, continuously heating for 22h, discharging the red hot furnace charge, and cooling to normal temperature through a coke quenching process to obtain the gasified coke containing the alkaline composite additive.

Comparative example 2

Adding no additive into the blended coal, heating to 950 ℃ in a dry distillation furnace in an air-isolated mode, continuously heating for 22h, discharging the red hot furnace charge, cooling to normal temperature through a coke quenching process, and taking the obtained gasified coke as reference coke.

The specific surface area and reactivity of the two coke groups were tested and the results are shown in table 2 below.

TABLE 2 gasification Coke reactivity and specific surface area comparison

Experimental groups	CRI（%）	Specific surface area (m)2/g）
			Contrast coke	53.8	20.8
Gasification coke added with composite additive	67.6	75.6

Example 3

The method for improving gasification coke reactivity by using the alkaline composite additive provided by the invention is implemented as follows:

the method comprises the following steps of selecting raw materials: sodium carbonate Na₂CO₃98.6 wt%; potassium carbonate K₂CO₃97.4 wt%; limestone CaO53 wt%;

drying the selected raw materials of sodium carbonate, potassium carbonate and limestone, and then respectively crushing until the granularity is less than or equal to 3 mm;

respectively weighing 30kg of crushed sodium carbonate, 25kg of crushed potassium carbonate and 40kg of crushed limestone according to parts by weight, mixing the materials together, stirring for 40 minutes, and uniformly mixing;

fourthly, dry grinding the uniformly stirred mixture to enable the particle size of the raw materials to be smaller than or equal to 150 meshes (0.1 mm); then calcining for 2 hours at the temperature of 260 ℃, and cooling to normal temperature to obtain the alkaline composite additive;

the coal material fed into the furnace is blended coal formed by blending 30wt% of mahogany long flame coal, 20wt% of 1/3 coking coal, 20wt% of fat coal and 30wt% of gas coal; the quality indexes of the blended coal are as follows: v_daf32.5%，A_d12.1%，FC_d58.6%，S_t,d0.73 percent; the caking index G =68, the Y value is 12, the fineness (≦ 3 mm) = 82.5%;

sixthly, adding an alkaline compound additive: adding the prepared alkaline composite additive into the blended coal at a weight ratio of 2: 100, insulating air in a dry distillation furnace, heating to 1000 ℃, continuously heating for 20h, discharging the red hot furnace charge, and cooling to normal temperature through a coke quenching process to obtain the gasified coke containing the alkaline composite additive.

Comparative example 3

Adding no additive into the blended coal, heating to 1000 ℃ in a dry distillation furnace in an air-isolated mode, continuously heating for 20 hours, discharging the red hot furnace charge, cooling to normal temperature through a coke quenching process, and taking the obtained gasified coke as reference coke.

The specific surface area and reactivity of the two coke groups were tested and the results are shown in table 3 below.

TABLE 3 gasification Coke reactivity and specific surface area comparison

Experimental groups	CRI（%）	Specific surface area (m)2/g）
			Contrast coke	55.2	23.8
Gasification coke added with composite additive	70.6	105.3

Example 4

The method for improving gasification coke reactivity by using the alkaline composite additive provided by the invention is implemented as follows:

the method comprises the following steps of selecting raw materials: sodium carbonate Na₂CO₃98.9 wt%; potassium carbonate K₂CO₃96.7 wt%; limestone CaO52wt%；

Drying the selected raw materials of sodium carbonate, potassium carbonate and limestone, and then respectively crushing until the granularity is less than or equal to 3 mm;

respectively weighing 25kg of crushed sodium carbonate, 27kg of crushed potassium carbonate and 45kg of crushed limestone in sequence according to parts by weight, mixing the materials together, stirring for 45 minutes, and uniformly mixing;

fourthly, dry grinding the uniformly stirred mixture to enable the particle size of the raw materials to be smaller than or equal to 150 meshes (0.1 mm); then calcining for 1.5 hours at 280 ℃, and cooling to normal temperature to obtain the alkaline composite additive;

the coal material fed into the furnace is blended coal formed by blending 40wt% of mahogany long flame coal, 15wt% of 1/3 coking coal, 25wt% of fat coal and 20wt% of gas coal; the quality indexes of the blended coal are as follows: v_daf32.5%，A_d13.2%，FC_d57.8%，S_t,d0.79 percent; the bonding index G =61, the Y value is 10.8, the fineness (≦ 3 mm) = 85.2%;

sixthly, adding an alkaline compound additive: adding the prepared alkaline composite additive into the blended coal at a weight ratio of 3: 100, insulating air in a dry distillation furnace, heating to 1050 ℃, continuously heating for 18h, discharging the red hot furnace charge, and cooling to normal temperature through a coke quenching process to obtain the gasified coke containing the alkaline composite additive.

Comparative example 4

Adding no additive into the blended coal, isolating air in a dry distillation furnace, heating to 1050 ℃, continuously heating for 18h, discharging the red hot furnace charge, cooling to normal temperature through a coke quenching process, and taking the obtained gasified coke as control coke.

The specific surface area and reactivity of the two coke groups were tested and the results are shown in table 4 below.

TABLE 4 gasification Coke reactivity and specific surface area comparison

Experimental groups	CRI（%）	Specific surface area (m)2/g）
			Contrast coke	52.7	20.2
Gasification coke added with composite additive	80.0	110.0

Example 5

The method for improving gasification coke reactivity by using the alkaline composite additive provided by the invention is implemented as follows:

the method comprises the following steps of selecting raw materials: sodium carbonate Na₂CO₃99.2 wt%; potassium carbonate K₂CO₃96 wt%; CaO51wt% of limestone;

drying the selected raw materials of sodium carbonate, potassium carbonate and limestone, and then respectively crushing until the granularity is less than or equal to 3 mm;

respectively weighing 20kg of crushed sodium carbonate, 20kg of crushed potassium carbonate and 50kg of crushed limestone in sequence according to parts by weight, mixing the materials together, stirring for 50 minutes, and uniformly mixing;

fourthly, dry grinding the uniformly stirred mixture to enable the particle size of the raw materials to be smaller than or equal to 150 meshes (0.1 mm); then calcining for 2 hours at the temperature of 260 ℃, and cooling to normal temperature to obtain the alkaline composite additive;

the coal material fed into the furnace is blended coal formed by blending 30wt% of mahogany long flame coal, 20wt% of 1/3 coking coal, 20wt% of fat coal and 30wt% of gas coal; the quality indexes of the blended coal are as follows: v_daf33.5%，A_d11.1%，FC_d58.3%，S_t,d0.82%; the bonding index G =63, the Y value is 11.2, the fineness (≦ 3 mm) = 86.3%;

sixthly, adding an alkaline compound additive: adding the prepared alkaline composite additive into the blended coal at a weight ratio of 4: 100, insulating air in a dry distillation furnace, heating to 1100 ℃, continuously heating for 16h, discharging the red hot furnace charge, and cooling to normal temperature through a coke quenching process to obtain the gasified coke containing the alkaline composite additive.

Comparative example 5

Adding no additive into the blended coal, heating to 1100 deg.C in a dry distillation furnace under air isolation, continuously heating for 16h, discharging red hot furnace material, quenching to normal temperature, and using the obtained gasified coke as reference coke.

The specific surface area and reactivity of the two coke groups were tested and the results are shown in table 5 below.

TABLE 5 gasification Coke reactivity and specific surface area comparison

Experimental groups	CRI（%）	Specific surface area (m)2/g）
			Contrast coke	55.6	20.0
Gasification coke added with composite additive	75.0	102.0

Claims (2)

1. A method for improving gasification coke reactivity by using a basic composite additive is characterized by comprising the following steps: the method is carried out according to the following steps:

the method comprises the following steps of selecting raw materials: sodium carbonate Na₂CO₃More than or equal to 98 wt%; potassium carbonate K₂CO₃More than or equal to 96 wt%; CaO of limestone is more than or equal to 51 wt%;

drying the selected raw materials of sodium carbonate, potassium carbonate and limestone, and then respectively crushing until the granularity is less than or equal to 3 mm;

respectively weighing 20-40 parts of crushed raw materials of sodium carbonate, 20-30 parts of potassium carbonate and 30-50 parts of limestone in sequence by weight, mixing the raw materials together, stirring for 30-50 minutes, and uniformly mixing;

fourthly, the uniformly stirred and mixed mixture is ground in a dry mode to enable the particle size of the raw material to be smaller than or equal to 150 meshes, then the mixture is calcined for 1-2 hours at the temperature of 260-300 ℃, and the mixture is cooled to normal temperature to obtain the alkaline composite additive;

the quality indexes of the selected blended coal are as follows: FC_d≥55%，V_daf≥25%，A_dNot more than 20%, G value not less than 50, Y value not less than 10, S_t，d＜1.5%；

Sixthly, adding the alkaline composite additive into the blended coal according to the weight ratio of the alkaline composite additive to the blended coal of 0.5-4: 100, insulating air in a dry distillation furnace, heating to 900-.

2. The method of claim 1 for increasing gasification coke reactivity with the basic complex additive, wherein: the blended coal is formed by blending a plurality of weakly caking coal, gas coal, coking coal, fat coal, main coking coal, gas fat coal, non-caking coal and long flame coal.