CN109054685B

CN109054685B - Coke powder adhesive, coke balls suitable for production of closed calcium carbide furnace and preparation method thereof, and production method of calcium carbide of closed calcium carbide furnace

Info

Publication number: CN109054685B
Application number: CN201811067463.4A
Authority: CN
Inventors: 黄元金; 黄程昱坤
Original assignee: 黄元金
Priority date: 2018-09-13
Filing date: 2018-09-13
Publication date: 2020-06-16
Anticipated expiration: 2038-09-13
Also published as: CN109054685A

Abstract

The invention discloses a coke powder adhesive, which is prepared from corn starch, closed electrode paste, petroleum coke, coal tar and carburant according to a certain proportion. The invention also discloses a method for preparing coke balls by using the coke powder adhesive, which comprises the following steps: a. feeding coke powder and a coke powder adhesive in proportion; b. humidifying and heating to control indexes; c. pressing and forming; d. and (5) drying. The invention also discloses a production method of the calcium carbide for the closed calcium carbide furnace, which is characterized in that the coke balls are mixed, and the mixing amount accounts for 50-60% of the total mass of the furnace carbon materials. The invention has the advantages that: 1) the prepared coke balls have little or no influence on fixed carbon, volatile matters and ash content of processing raw materials, the granularity, cold strength, hot strength and water resistance of the obtained coke balls can completely meet the requirements of calcium carbide production, and the high mixing proportion of the total mass of the coke balls in the calcium carbide production accounting for more than 50 percent of the total mass of the furnace carbon materials is realized; 2) the coke ball pressing process is simple, and the ball manufacturing cost is low.

Description

Coke powder adhesive, coke balls suitable for production of closed calcium carbide furnace and preparation method thereof, and production method of calcium carbide of closed calcium carbide furnace

Technical Field

The invention relates to a calcium carbide production process, in particular to a method for recycling coke powder in calcium carbide production.

Background

The main equipment for producing the calcium carbide is a calcium carbide furnace, the sealed calcium carbide furnace means that the electrochemical reaction for producing the calcium carbide is carried out in a sealed container, external air cannot enter the reactor, coke and limestone are added into the furnace according to a certain proportion in the production process of the calcium carbide, and a calcium carbide product is generated by the reaction after the three-phase electrodes are electrified to generate electric heat.

The coke is an important raw material for calcium carbide production, is used as a reducing agent in furnace burden, has a great influence on the calcium carbide production due to the granularity of the coke, and is suitable for 15-40 mm generally. However, during the transportation, storage and use of coke, pulverization occurs and a certain amount of coke powder, called coke powder for short, is formed. The particle size of the coke powder is usually less than 5mm, and the mass of the coke powder is generally 10-20% of the total mass. Because the particle size, strength, hardness and other aspects of the coke powder can not meet the requirements of the calcium carbide production process, the coke powder can only be used as electric coal or used for other civil uses or even discarded, which not only does not fully embody the inherent value of the coke powder, but also causes environmental pollution. In the present day that the energy is sharply tensed, the resource waste is serious. If the coke powder can be made into coke balls for the calcium carbide production, the cost and the resource can be saved undoubtedly.

The production of calcium carbide has very strict requirements on various physicochemical properties of raw material coke, in order to improve the utilization value of undersize products, many enterprises try to mix coke powder and adhesive and press the mixture into balls for recycling, the regenerated coke balls can be successfully used for producing yellow phosphorus at present, but the coke balls do not meet the production requirements of the calcium carbide, particularly the thermal stability and compressive strength under a thermal state cannot meet the requirements of the calcium carbide production process, the calcium carbide production is greatly influenced, or the blending proportion is too low, so that the calcium carbide production has no practical economic value and is abandoned.

Disclosure of Invention

In order to realize that the coke powder pressed balls can be used for calcium carbide production, in recent years, research, development, tracking, experiments and production are carried out on how to break through the technical bottleneck of the coke powder pressed balls, and finally, the special adhesive for the coke powder pressed balls is successfully developed.

The technical scheme adopted by the invention is as follows: the coke powder adhesive comprises the following components in percentage by mass: 56-64% of corn starch, 18-22% of sealed electrode paste, 8-12% of petroleum coke, 4-6% of coal tar and 4-6% of carburant.

The inventor considers that the biggest technical bottleneck of coke powder pelletizing and recycling is that no adhesive can ensure enough adhesive strength under the required coke ball size, and simultaneously, the coke ball can have thermal stability, fixed carbon, proper volatile matter, enough thermal strength, cold strength and water resistance which are required by the calcium carbide production process. In brief, the use of any binder adversely affects the fixed carbon, volatile matter, ash content of the coke powder, but does not ensure sufficient adhesive strength without adding sufficient binder, thereby adversely affecting the hot strength, cold strength and water resistance of the coke ball. This has made this study problematic.

The inventors have made many studies on this in the early days, including improvement on the basis of inorganic binders, polymer binders, and resin-based binders, but eventually failed, mainly because the addition of new components leads to a significant decrease in the inherent adhesiveness of the binder. Finally, the inventor determines that the corn starch is used as a main component, and finds that the corn starch is matched with the closed electrode paste, the petroleum coke, the coal tar and the carburant in a certain proportion, so that the adhesive property of the adhesive can be ensured not to be obviously influenced, the thermal stability and the fixed carbon of the coke ball can be maintained, the volatile matter is stabilized, and the thermal strength is improved. Experiments prove that although the product coke balls cannot completely replace coke, the product coke balls can not influence the calcium carbide production under the condition that the total mass of the coke balls accounts for more than 50 percent of the total mass of the furnace carbon material, and the method is a great technical progress in the field.

Experiments prove that the coke ball pressed by the coke powder adhesive can achieve the following technical indexes:

1. granularity: 15-40 mm;

2. fixing carbon: the reduction is 0.5-1% on the basis of processing raw material coke powder;

3. volatile components: the temperature rises by 0.5 to 1 percent on the basis of processing raw material coke powder;

4. ash content: the coke powder is not increased relative to the processing raw material;

5. moisture content: less than 1.5 percent;

6. cold strength: more than 150 kg;

7. thermal strength (compressive strength after constant temperature of 900 ℃ for 1 hour): more than 15kg without burning loss and damage;

8. water resistance: soaking in water for 10 hr;

therefore, the coke balls prepared by using the coke powder adhesive have little or no influence on fixed carbon, volatile matters and ash content of processing raw materials, and the granularity, cold strength, hot strength and water resistance of the obtained coke balls can completely meet the requirements of calcium carbide production.

Preferably, the coke powder adhesive of the invention can be composed of the following components by mass percent: 60% of corn starch, 20% of closed electrode paste, 10% of petroleum coke, 5% of coal tar and 5% of carburant.

In addition, the invention also provides a preparation method of the coke ball suitable for the production of the closed calcium carbide furnace, which comprises the following steps:

A. feeding coke powder and the coke powder adhesive of claim 1 in proportion to obtain a mixture;

B. fully stirring the mixture, humidifying and heating the mixture to a control index to obtain a material to be pressed;

C. pressing and molding the material to be pressed by a ball press machine to obtain a molded material;

D. and drying the molding material to obtain the coke ball.

In the background art, the applicant has already explained that the coke powder refers to coke powder with the particle size of less than 5mm formed by pulverization of coke in the using process, and the using process refers to any condition capable of causing pulverization of coke in the using process of coke, and comprises a production process, a transportation process, undersize materials before the coke is sent into a calcium carbide furnace for use, dust generated in a drying process and the like of the coke.

As a further improvement of the method, in the step A, the coke powder and the coke powder adhesive are fed according to the mass ratio of 100: 3-3.5. The use ratio of the coke powder and the coke powder adhesive is an important process parameter, and the addition of too little adhesive can cause the bonding effect, cold strength, hot strength and water resistance of the coke ball to not meet the process requirements; while the use of too much binder will result in a decrease in the coke ball fixed carbon content and an increase in volatiles. Therefore, as one skilled in the art can appreciate, the binder usage ratio can be determined by routine experimentation, and the coke powder binder should be used as little as possible to ensure the binding effect of the coke balls. The inventors have provided experimentally determined proportions of the above-described coke powder binder for clear understanding and implementation by the skilled artisan, including those not skilled in the art.

As a further improvement of the method, water is added in the step B according to the mass ratio of the mixture to the water of 100: 15-20 for humidification treatment. The purpose of adding water is to facilitate molding and demolding in the pressing process: too much or too little water can have great influence on molding and demolding.

As a further improvement of the invention, the temperature of the material to be pressed in the step B is 65-80 ℃, and experiments prove that the ball pressing temperature has a large influence on the performance of the final coke ball, and the reason is probably because the raw material of the coke powder adhesive contains the closed electrode paste and the corn starch, the temperature is set in the softening point range of the electrode paste after the heating treatment, and the temperature range of 65-80 ℃ is the optimal temperature range for modifying the corn starch.

As a further improvement of the invention, the pressing pressure in the step C is 0.3-0.5 MPa.

As a further improvement of the invention, the coke ball obtained in the step D has a moisture content of less than 1.5 percent by mass.

As a further improvement of the method, the particle size of the coke ball obtained in the step D is 15-40 mm.

The coke ball prepared by the method is suitable for producing the closed calcium carbide furnace.

The invention also provides a production method of the calcium carbide of the closed calcium carbide furnace, wherein the upper furnace carbon material used as a reducing agent in the production method of the calcium carbide of the closed calcium carbide furnace comprises the coke balls suitable for production of the closed calcium carbide furnace, and the total mass of the coke balls suitable for production of the closed calcium carbide furnace accounts for 50-60% of the total mass of the upper furnace carbon material. The coke ball additive can be used by adding coke balls accounting for 50-60% of the total mass of the furnace carbon material, and calcium carbide production is not affected.

The invention has the beneficial effects that: 1) the coke balls prepared by using the coke powder adhesive have little or no influence on fixed carbon, volatile matters and ash content of processing raw materials, the granularity, cold strength, hot strength and water resistance of the obtained coke balls can completely meet the requirement of calcium carbide production, and the calcium carbide production process cannot be influenced under the condition that the total mass of the coke balls accounts for more than 50 percent of the total mass of furnace carbon materials in the calcium carbide production of the closed calcium carbide furnace; 2) the coke ball pressing process is simple, and the ball manufacturing cost is low.

Drawings

FIG. 1 shows a coke ball of a closed calcium carbide furnace, which is scraped off during water leakage inspection in the furnace, wherein the shape of the coke ball is intact, and part of granular matters are burnt coke.

FIG. 2 shows the compressive strength of the coke ball obtained in the first example after a constant temperature of 900 ℃ for one hour in a muffle furnace.

Detailed Description

The invention is further illustrated with reference to the following figures and examples.

The first embodiment is as follows:

the coke balls were prepared as follows:

(1) feeding the coke powder and the coke powder adhesive according to the proportion of 100:3 to obtain a mixture; the properties of the coke powder are as follows: 12.4% of ash, 3.6% of volatile matter, 84% of fixed carbon and 3.7mm of average particle size; the coke powder adhesive consists of the following components: 60% of corn starch, 20% of closed electrode paste, 10% of petroleum coke, 5% of coal tar and 5% of carburant.

(2) Fully stirring the mixture by using a vertical stirrer, adding water into the mixture while stirring to humidify the mixture, wherein the mass ratio of the mixture to the water is 100:16, and then heating the humidified material to 80 ℃ to obtain the material to be pressed.

(3) And pressing and molding the material to be molded by a ball press machine, wherein the pressing pressure is 0.4MPa, so as to obtain the molding material, and the particle size of the molding material is about 34 mm.

(4) And drying the molding material by using hot gas at the tail of an industrial furnace until the water content is 1.0 percent to obtain the coke ball. The properties of the coke ball, such as fixed carbon, volatile components, ash content and the like, are detected, and the detection results are shown in table 1.

(5) Adding an upper furnace carbon material into a closed calcium carbide furnace (40500KVA) through an upper end pipeline, wherein the upper furnace carbon material comprises the following components: 45% of coke (ash content is 12.4%, volatile matter is 3.6%, fixed carbon is 84%, and average particle size is 26mm), and 55% of coke balls prepared in the step (4); heating the mixture to 2000 ℃ in a closed electric furnace, and reacting according to the following formula to generate calcium carbide: GaO +3C → CaC₂+ CO; and taking out the molten calcium carbide from the furnace bottom, cooling and crushing to obtain the calcium carbide product. And continuously producing for one month, and counting the calcium carbide production conditions, wherein the results are shown in a table 2.

Example two:

the coke balls were prepared as follows:

(1) feeding the coke powder and the coke powder adhesive according to the proportion of 100:3.3 to obtain a mixture; the properties of the coke powder are as follows: 12.4% of ash, 3.6% of volatile matter, 84% of fixed carbon and 3.7mm of average particle size; the coke powder adhesive consists of the following components: 64% of corn starch, 18% of closed electrode paste, 9% of petroleum coke, 4% of coal tar and 5% of carburant.

(2) Fully stirring the mixture by using a vertical stirrer, adding water into the mixture while stirring to humidify the mixture, wherein the mass ratio of the mixture to the water is 100:20, and then heating the humidified material to 65 ℃ to obtain the material to be pressed.

(3) And pressing and molding the material to be molded by a ball press machine, wherein the pressing pressure is 0.5MPa, so as to obtain the molding material, and the particle size of the molding material is about 40 mm.

(4) And drying the molding material by using hot gas at the tail of an industrial furnace until the water content is 1.5 percent to obtain the coke ball. The properties of the coke ball, such as fixed carbon, volatile components, ash content and the like, are detected, and the detection results are shown in table 1.

(5) Adding an upper furnace carbon material into a closed calcium carbide furnace (40500KVA) through an upper end pipeline, wherein the upper furnace carbon material comprises the following components: 50% of coke (ash content is 12.4%, volatile matter is 3.6%, fixed carbon is 84%, and average particle size is 26mm), and 50% of coke balls prepared in the step (4); heating the mixture to 2000 ℃ in a closed electric furnace, and reacting according to the following formula to generate calcium carbide: GaO +3C → CaC₂+ CO; and taking out the molten calcium carbide from the furnace bottom, cooling and crushing to obtain the calcium carbide product. And continuously producing for one month, and counting the calcium carbide production conditions, wherein the results are shown in a table 2.

Example three:

the coke balls were prepared as follows:

(2) feeding the coke powder and the coke powder adhesive according to the proportion of 100:3.5 to obtain a mixture; the properties of the coke powder are as follows: 12.4% of ash, 3.6% of volatile matter, 84% of fixed carbon and 3.7mm of average particle size; the coke powder adhesive consists of the following components: 56% of corn starch, 22% of closed electrode paste, 10% of petroleum coke, 6% of coal tar and 6% of carburant.

(2) Fully stirring the mixture by using a vertical stirrer, adding water into the mixture while stirring to humidify the mixture, wherein the mass ratio of the mixture to the water is 100:15, and then heating the humidified material to 70 ℃ to obtain the material to be pressed.

(3) And pressing and molding the material to be molded by a ball press machine, wherein the pressing pressure is 0.3MPa, so as to obtain the molding material, and the particle size of the molding material is about 18 mm.

(5) Adding an upper furnace carbon material into a closed calcium carbide furnace (40500KVA) through an upper end pipeline, wherein the upper furnace carbon material comprises the following components: 48% of coke (ash content is 12.4%, volatile matter is 3.6%, fixed carbon is 84%, and average particle size is 26mm), and 52% of coke balls prepared in the step (4); heating the mixture to 2000 ℃ in a closed electric furnace, and reacting according to the following formula to generate calcium carbide: GaO +3C → CaC₂+ CO; and taking out the molten calcium carbide from the furnace bottom, cooling and crushing to obtain the calcium carbide product. And continuously producing for one month, and counting the calcium carbide production conditions, wherein the results are shown in a table 2.

Comparative example one:

the calcium carbide is produced by adopting the process and equipment which are the same as those in the first embodiment, the difference is that all the upper furnace carbon materials use coke (ash content is 12.4%, volatile component is 3.6%, fixed carbon is 84%, and average particle size is 26mm), the calcium carbide is continuously produced for one month, the calcium carbide production conditions are counted, and the results are shown in table 2.

Cost and economic benefits:

1. the ball pressing cost is as follows: 420 yuan/ton. Wherein: 54.4 yuan/ton value-added tax invoice, 220 yuan/ton special coke powder adhesive and 33 yuan/ton equipment depreciation in 5 years; the labor cost is 30 yuan/ton; the production cost is 15 yuan/ton; the repair cost is 20 yuan/ton; the profit is 47.6 yuan/ton.

2. And (4) scheme yield: the selling price of coke is 600 yuan/ton, and the selling price of coke powder is 150 yuan/ton. Because the moisture of the coke powder is more than 15 percent, the moisture of the coke balls is less than 1.5 percent, the coke undersize reaches 15 percent on average, and the coke undersize is almost zero, the actual price difference can be regarded as 600 x 1.28-150 Yuan/ton, the production cost of the coke balls is reduced by 420 Yuan/ton, the income of a proprietor per ton is 198 Yuan, if the ball is pressed by 120000 tons in one year (if the internal coke powder amount is not enough, the coke powder pressed balls can be purchased outside, the mixing amount of the coke balls can reach 50-60 percent of the carbon material amount of the upper furnace), and 2376 Yuan is created in the whole year. If the dust removal ash of the drying kiln is used, the benefit is more considerable. Table 1: coke ball property detecting meter

Fixed carbon

Volatile component

Ash content

Cold Strength/kg

Thermal Strength/kg

Water resistance/h does not disperse

Example one

83.4％

4.1％

12.5％

312

26.7

16

Example two

83.1％

4.5％

12.4％

284

24.8

13

EXAMPLE III

83.3％

4.2％

12.5％

324

25.6

16

Table 2: calcium carbide production conditions

	Post-label yield	Standard post-consumer unit consumption	Rate of equipment operation
				Example one	6814.45	3120	98.45％
Example two	6731.66	3187	98.26％
				EXAMPLE III	6781.59	3115	97.53％
Comparative example 1	6846.32	3057	98.53％

Claims

1. The coke powder adhesive comprises the following components in percentage by mass: 56-64% of corn starch, 18-22% of sealed electrode paste, 8-12% of petroleum coke, 4-6% of coal tar and 4-6% of carburant.

2. The coke powder adhesive of claim 1, which comprises the following components in percentage by mass: 60% of corn starch, 20% of closed electrode paste, 10% of petroleum coke, 5% of coal tar and 5% of carburant.

3. The preparation method of the coke ball suitable for the production of the closed calcium carbide furnace comprises the following steps:

A. feeding coke powder and the coke powder adhesive of claim 1 according to the mass ratio of 100: 3-3.5 to obtain a mixture;

D. and drying the molding material to obtain the coke ball.

4. The preparation method of the coke ball suitable for the production of the closed calcium carbide furnace according to claim 3, which is characterized by comprising the following steps: and B, adding water according to the mass ratio of the mixture to the water of 100: 15-20 for humidification treatment.

5. The preparation method of the coke ball suitable for the production of the closed calcium carbide furnace according to claim 3, which is characterized by comprising the following steps: and C, in the step B, the temperature of the material to be pressed is 65-80 ℃.

6. The preparation method of the coke ball suitable for the production of the closed calcium carbide furnace according to claim 3, which is characterized by comprising the following steps: and C, the pressing pressure in the step C is 0.3-0.5 MPa.

7. The preparation method of the coke ball suitable for the production of the closed calcium carbide furnace according to claim 3, which is characterized by comprising the following steps: and D, the water content of the coke ball obtained in the step D is less than 1.5 percent by mass.

8. The preparation method of the coke ball suitable for the production of the closed calcium carbide furnace according to claim 3, which is characterized by comprising the following steps: and D, the particle size of the coke ball obtained in the step D is 15-40 mm.

9. The coke ball prepared by the method of any one of claims 3 to 8 and suitable for production of the closed calcium carbide furnace.

10. The production method of the calcium carbide in the closed calcium carbide furnace is characterized by comprising the following steps: the carbon material used as a reducing agent in the closed calcium carbide furnace calcium carbide production method comprises the coke balls suitable for production in the closed calcium carbide furnace, according to claim 9, wherein the total mass of the coke balls suitable for production in the closed calcium carbide furnace accounts for 50-60% of the total mass of the carbon material.