JP2007321030A - Method for producing coke - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing coke able to enhance coke strength without diffusing carbon dioxide, a greenhouse gas, in the atmosphere in treating fatty acid pitch in a coke production process. <P>SOLUTION: The amount of addition of the fatty acid pitch is brought to be ≤2.5 wt.%, preferably 0.5-2.0 wt.%, in adding the fatty acid pitch together with coal into a coke oven. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing coke that improves the strength of coke.

  Fatty acid pitch is generated in the product manufacturing process of a factory that manufactures oleochemical products. Such fatty acid pitch is processed by burning, and is used as, for example, boiler fuel replacing C heavy oil. Moreover, the technique disclosed by the following patent documents 1 and 2 is known as a prior art which uses and processes fatty acid pitch by mixing with other substances.

  Patent Document 1 relates to an oil-in-water emulsion composition containing heavy oil, water, a surfactant, and a fatty acid distillation bottom, and the fatty acid distillation bottom is beef tallow, palm oil, palm oil. This refers to by-products generated when fatty acids are produced from raw materials and the like, and the fatty acid distillation bottoms treated as industrial waste are to be reused as fuel.

  Patent Document 2 relates to a method for producing a cement firing auxiliary fuel composition having thixotropy using waste, and as waste, liquid waste containing oil and / or water containing liquid components, oil and / or Or two or more kinds of wastes selected from liquid wastes containing solids in addition to liquid components containing water, and more specifically animal oils, vegetable oils, fatty acids, oils and fats, esters, etc. Has been raised.

JP-A-6-264077 JP 2001-329276 A JP 2000-53970 A Japanese Patent Laid-Open No. 2001-200259

  Therefore, the above-mentioned treatment method can be considered for the fatty acid pitch, but when used as a fuel as described above, a large amount of carbon dioxide gas known as a greenhouse gas that causes global warming by combustion is generated, Carbon dioxide gas will diffuse directly into the atmosphere.

  On the other hand, techniques disclosed in Patent Documents 3 and 4 are known as techniques for adding and processing other substances to coke. In Patent Document 3, when coke is produced by heating and distilling coal, heavy oil and waste plastic are mixed, heated and polymerized, and added to the raw coal as a coking aid for the coal to produce a coke oven. Discloses a method for producing coke to be charged. This produces an effect of increasing the coke strength. However, since the additive is heated in advance, carbon dioxide or the like may be diffused into the atmosphere.

  In the technology disclosed in Patent Document 4, organic waste is mixed with coking coal at a ratio of 0.05 to 1% by mass and charged into a coking oven carbonization chamber. It is one that is carbonized. Examples of organic waste include food waste, agricultural and fishery waste, garbage waste, sludge, pulp sludge, and waste wood. Although it has been described that the addition of these organic wastes does not affect the coke strength, the effect of increasing the coke strength has not occurred.

  The present invention has been made in view of the above circumstances, and its problem is to prevent the carbon dioxide gas, which is a greenhouse gas, from diffusing into the atmosphere when processing the fatty acid pitch in the coke production process, and coke strength. It is providing the manufacturing method of the coke which can raise.

In order to solve the above problems, a method for producing coke according to the present invention is as follows.
When the fatty acid pitch is charged together with coal into the coke oven, the addition amount of the fatty acid pitch is 2.5 wt% or less.

  According to this structure, when charging coal into a coke oven for producing coke, the fatty acid pitch is charged together with the coal. As a form of charging fatty acid pitch together with coal, for example, it can be charged in a state where fatty acid pitch is added to coal, or can be charged by a route different from coal, but is limited to a specific form. is not. By treating fatty acid pitch with coal in a coke oven, it can be recovered as products and by-products in the coke manufacturing industry such as coke, coke oven gas, tars, etc., without diffusing carbon dioxide gas into the atmosphere, It can be used effectively. Moreover, although mentioned later in detail, it was confirmed that the coke strength is increased by setting the amount of fatty acid pitch added to coal to 2.5 wt% or less (however, more than 0%). As a result, it is possible to provide a coke production method capable of preventing the carbon dioxide gas, which is a greenhouse gas, from diffusing into the atmosphere and increasing the coke strength.

  In this invention, it is preferable that the addition amount of fatty acid pitch shall be 0.5-2.0 wt%. Thereby, coke intensity | strength can be improved significantly.

  A preferred embodiment of a method for producing coke according to the present invention will be described. First, the coke production process will be briefly described.

<Coke production process>
Coal is landed from a coal carrier on the quay and transported to a coal storage by a belt conveyor. In coal storage, it is stored for each property (brand) of coal. The amount of coal stored in the coal storage is dispensed by the reclaimer for each brand and sent to the blending tank by the belt conveyor. The blending tank has a plurality of tanks, and one brand of coal is stored in one blending tank. Coal has high and low costs due to its properties, and in order to produce high quality coke at a low cost, coal with different properties is cut out from multiple blending tanks at the optimum blending ratio and used as coking coal for coke production. Is completed.

  That is, for coke production, various types (brands) of coal are imported from overseas and stored in the coal storage for each brand. This is because coal mined in each coal mine has different properties for each coal mine, and the properties of coke produced differ depending on the properties. Therefore, by combining multiple coals, it is requested by the user at the cheapest cost. This is because it is necessary to satisfy the coke properties (quality).

  The blended coal is pulverized to a predetermined particle size by a pulverizer, and adjusted to an appropriate particle size according to the properties of each coal brand. Moreover, you may make it mix | blend caking material (asphalt pyrolysis pitch etc.) with coal, and grind | pulverize coal with caking material.

  Coal pulverized in the pulverizer is transported to a coke bin (coal tower) of a coke oven by a belt conveyor. Between the pulverizer and the coal bottle, a coal humidity control facility, a forming coal facility, or the like may be disposed. Various brands of coal and binders pulverized by a pulverizer are conveyed by a belt conveyor and are naturally mixed at a belt connecting portion or the like. For example, the coal humidity control equipment aims to reduce the water content of pulverized coal, reduce the amount of energy required for coke production, and improve the stable operation and productivity of the coke oven.

  The pulverized coal is temporarily stored in a coal bin (coal tower), and then charged into a coke oven by a charging vehicle, followed by dry distillation (steamed). The coalbin is provided with a coal storage facility, and is configured to fill the hopper of a charging vehicle for charging the coal into the coke oven from above. Coal is carbonized to form coke, which is pushed out of the coke oven by an extruder. The obtained coke is in a red hot state, and is extinguished by wet fire extinguishing equipment or dry fire extinguishing equipment using nitrogen gas.

  The extinguished coke is sieved in the sieving section and then becomes product coke. In addition, by-products such as coke oven gas and tars are recovered in the carbonization process, and become products. Coke is used as a raw material for iron making, by-product coke oven gas is used as a fuel and hydrogen raw material, and tars are used as chemical raw materials.

<Processing in coke oven>
Next, the processing content of the fatty acid pitch in the coke oven 10 will be described with reference to the conceptual diagrams of FIGS. This invention provides the method of processing the fatty-acid pitch which generate | occur | produces in the product manufacturing process of the factory which manufactures oleochemical products with a coke oven. An example of the analysis result of fatty acid pitch is shown in FIG. When processing fatty acid pitch as fuel, carbon dioxide gas is released to the atmosphere, which has an adverse effect on the environment, but in the case of processing in a coke oven, rather than diffusing carbon dioxide gas into the atmosphere, rather The advantage is that it can be recovered as a product or by-product.

  Therefore, the fatty acid pitch is added to the coal and charged into the coke oven 10. In other words, the coal feeding belt 11 is used to transfer the coal to the coal bin on the coke oven 10. The addition of the fatty acid pitch may be supplied to the charging vehicle in a form in which the fatty acid pitch is added to the coal on the coal feeding belt 11 as shown in FIG. 1, or as shown in FIG. May be added to the hopper of the charging vehicle. The fatty acid pitch charged into the coke oven 10 is carbonized simultaneously with the coal in the coal carbonization process, and is recovered as a by-product such as coke as a product, tar, crude light oil, and coke oven gas (COG). In order to collect each by-product, a tar tank 12, a crude light oil tank 13, and a COG holder 14 are provided.

  In more detail, since the fatty acid pitch put into the coke oven 10 together with coal is heated and distilled in the coke oven 10, the fatty acid pitch itself is also thermally decomposed. As a result of this thermal decomposition, a part of the fatty acid pitch remains as solid carbon in the coke, a part becomes a gas body, and a part further changes into a liquid substance such as coal tar. Therefore, the pyrolyzed carbon solid content is contained in coke which is the same solid, and is recovered as coke which is a product. In addition, gas bodies and liquids are recovered together with coal pyrolysis products in the gas, tar, and crude light oil recovery equipment (shown in FIG. 1 as numbers 12, 13, and 14) that are usually provided in the operation of the coke oven 10. The

<Coke strength confirmation experiment>
Next, an experiment was conducted to confirm the coke strength when coke was produced by adding fatty acid pitch to coal for coke production. The movable wall test furnace (approximately 300 kg scale) shown in FIG. 4 was tested, and the test was performed with a carbonized wheel 18 (functioning as a carbonization chamber) sandwiched between the fixed wall 16 and the movable wall 17. Do. Coal and fatty acid pitch were charged through an inlet 19 provided on the furnace. The addition amount of fatty acid pitch is no addition, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 5 wt% The test was conducted at 11 stages of% addition.

  FIG. 5 is a graph showing the test results, where the horizontal axis indicates the amount of fatty acid pitch added (wt%), and the vertical axis indicates the coke strength. The coke strength is indicated by the drum index (DI150 rotation 15 mm), and it was recognized that the addition of fatty acid pitch increases the coke strength. It was also confirmed that the drum index, which is coke strength, takes the maximum value when the amount of fatty acid pitch added is 1 wt%.

  The drum index (DI) expresses the strength of coke against impact and friction as an index, and is widely used for evaluation of coke strength, and is measured by a rotational strength test method. The drum used in this test has an inner diameter and a length of 1500 mm, and six wings with a height of 250 mm are vertically fixed to the inner surface. 10kg of coke of 50mm or more is put in this drum, and after 30 or 150 revolutions at 15rpm, it is sieved with 50mm, 25mm, and 15mm sieves. .

  As can be seen from the graph of FIG. 5, an increase in coke strength is observed when the amount of fatty acid pitch added is 2.5 wt% or less (however, more than 0%). In particular, the remarkable effect is recognized by setting it as 0.5 to 2 wt%.

<Dry yield test>
Next, the yield yield experiment of fatty acid pitch was performed using the experimental apparatus shown in FIG. The experimental method will be described below. First, based on 75 g of coal, the addition rate of fatty acid pitch is changed to 0%, 2.0 wt%, and 5.0 wt% to obtain a sample, which is put into a dry distillation retort 20 (small dry distillation test furnace). Using a heating electric furnace 21 that can heat the dry distillation retort 20 from the outside, the temperature was raised to 900 ° C. at 5 ° C./min and held at 900 ° C. for 2 hours, and the dry distillation retort 20 containing the sample was heated to dry distillation. . The pyrolysis gas and liquid components that have come out of the dry distillation retort 20 reach the secondary cracking furnace 23 that surrounds the outside of the pipe by the pipe 22. The pyrolysis gas and liquid component further heated by the secondary decomposition heating furnace 23 through the pipe 22 are cooled by the cooler 24 and the gas cooler 25, and the liquid component is collected in the liquid component collection pots 25a and 25b. Be collected. The pyrolysis gas from which the liquid component has been cooled and collected passes through the gas filter 26 and is then stored in the gas collection container 27. Of the liquid components, those that are likely to aggregate due to cooling are collected in the preceding liquid component collection pot 25a, and those that are difficult to aggregate are collected in the subsequent liquid component collection pot 25b over time.

  After the dry distillation, the amount of each product was quantified. The weight remaining in the dry distillation retort 20 was measured and used as the weight of coke. The adhering liquid in the pipe 22 was completely transferred to the liquid component collection pots 25a and 25b, and the liquid component was recovered by separating the liquid component into an organic component and water, and the respective weights were measured. Moreover, the gas volume in the gas collection container 27 was measured, and the collected gas was subjected to gas composition analysis using a gas chromatograph (GC-14BPT manufactured by Shimadzu Corporation). In the case of coal only, when each fatty acid pitch is added, the amount of each product is quantified, and each product obtained by pyrolyzing the fatty acid pitch based on the difference between when the fatty acid pitch is not added and when it is added The amount of (yield) was determined. No difference was found in the product weight ratio obtained from the fatty acid pitch based on the difference between when the fatty acid pitch was added and when the fatty acid pitch was not added. .

The weight ratio of coke: gas: organic component: other product obtained from the fatty acid pitch is approximately 7: 80: 11: 2, and most of the product is recovered as gas. Here, the organic component is a by-product tar or crude light oil obtained by coal dry distillation in the coke oven 10. The composition of the gas obtained from the fatty acid pitch obtained from the gas composition analysis results is shown in Table 1. The calorific value of the gas obtained from the fatty acid pitch was about 6800 kcal / Nm ³ , which was about 1.6 times the coke oven gas calorific value when no normal fatty acid pitch was added.

  As described above, by adding the fatty acid pitch, which is a non-product generated in the product manufacturing process of the factory that manufactures oleochemical products, to the coal charged into the coke oven 10 and processing it in the coke oven 10, coke quality is achieved. It was confirmed that it can be recovered as coke, coke oven gas, and other by-products, and can be used effectively.

  If the fatty acid pitch is simply used as a fuel, carbon dioxide gas, which is a greenhouse gas, is diffused directly into the atmosphere, which adversely affects global environmental protection. It can be changed once to a raw material or a chemical raw material, and direct generation of carbon dioxide gas can be suppressed. By the way, if the fatty acid pitch is dry-distilled, it can be converted into coke and fuel gas as a substitute for coal, so that carbon dioxide gas of about 2.8 tons from 1 ton of fatty acid pitch can be suppressed.

  The pour point of the fatty acid pitch is about 28 ° C., and it is difficult to flow at room temperature level. However, since it melts and lowers its viscosity when heated, it can be heated by using a heat source around the coke oven 10 to heat the liquid. Can be transported in a state.

<Another Embodiment of Fatty Acid Pitch Addition Method>
Next, another embodiment of the method for adding fatty acid pitch will be described. The method described above is a method in which the fatty acid pitch is added alone to the coal, but the fatty acid pitch can be mixed with tar soot and added to the coal on the coal feeding belt 11 as shown in FIG. Techniques for adding tar soot generated in coke oven operation to a coke oven are disclosed in, for example, Japanese Patent Application Laid-Open Nos. 9-40968 and 52-98043.

  The procedure until the fatty acid pitch is added to the coal charged into the coke oven 10 will be described. Tar cake is separated in the process of recovering tar, which is a by-product obtained during coke production, and as shown in FIG. 7, a temperature-controlled tar cake tank 30 is used.

  The fatty acid pitch received in the coke plant is put in the tar tank 30 and stored in a mixed state with the tar tank. The tar cake has a higher viscosity when the temperature is lowered, and solidifies when the fatty acid pitch is cooled. Therefore, the tank is heated with steam, and the contents (a mixture of the tar cake and the fatty acid pitch) can be flowed by the pump 31. It is in a state having a degree of fluidity. The tar soot and fatty acid pitch stored in the tank 30 can be transported by the pump 31 and added to the coal on the coal feeding belt 11. The fatty acid pitch added together with the tar soot is charged into the coke oven 10 and processed.

  Fatty acid pitch is semi-solid at normal temperature and cannot be transferred as it is by using a pump or piping, but it can be transferred by piping by keeping the temperature at 28 ° C. or higher and 80 ° C. or lower together with tar soot. Since the fatty acid pitch can be added using an apparatus for adding tar soot, the fatty acid pitch can be processed without requiring a large capital investment.

  As shown in the fatty acid pitch analysis table of FIG. 3, the pour point of the fatty acid pitch is 27.5 ° C. Therefore, the heating condition in the tar tank 30 is preferably 28 ° C. or higher. It is preferably 80 ° C. or lower, which does not require excessive heating and does not require extra energy.

  According to the above configuration, the fatty acid pitch can be processed in the coke oven 10 using a conventional tar soot processing facility without producing a special device. Moreover, since the fatty acid pitch can be transferred using the pump 31, it can be added at a constant rate by adjusting the transport speed. Since it is stored in the tar soot tank 30, there is almost no odor diffusion or fatty acid pitch scattering.

<Another embodiment of fatty acid pitch charging>
As a method of charging the fatty acid pitch into the coke oven 10 as described above, a method of charging coal and the fatty acid pitch into the charging vehicle by different routes, a method of adding to the coal on the coal feeding belt 11, and a method of adding to the coal In this case, the method of adding together with tar koji has been described, but these are only examples, and as the present invention, the method and apparatus for charging fatty acid pitch into the coke oven is not limited to a specific form. Absent.

  In the present embodiment, the coke oven 10 is charged in a form in which fatty acid pitch is added to coal, but a transfer route for transferring fatty acid pitch is provided separately from the transfer route of coal, and this dedicated transfer route is used. The fatty acid pitch may be put into the coke oven 10. When the fatty acid pitch is charged, it may be charged in a solid / semi-solid state or a fluid state.

  When fatty acid pitch is added to coal, it is added in the pre-process of charging into the coke oven 10, but it can be set appropriately as to which stage it is added. Also when adding to coal, you may add in any state of a solid and semi-solid state, and the state which has fluidity | liquidity.

  When storing in a tank, it may be stored in a tar tank with a tar tank instead of using a dedicated tank for storing the fatty acid pitch. In the case of storing, it is preferable to store it in a state of being heated to a predetermined temperature and having fluidity. When the tank is provided, the tank can be installed at an appropriate place. For example, a tank is attached to a charging vehicle 10a for charging coal into the coke oven 10 and a fatty acid pitch is put therein, and then a fatty acid is introduced from the charging hole of the coal simultaneously with the charging of the coal using a pipe. The pitch can also be placed in a coke oven. Various other modifications can be considered.

The figure which shows the processing outline (1) in the coke oven of fatty acid pitch The figure which shows the processing outline (2) in the coke oven of fatty acid pitch The figure which shows an example of the analysis result of fatty acid pitch Diagram showing the configuration of the movable test furnace Experimental results showing relationship between added amount of fatty acid pitch and coke strength The figure which shows the experimental equipment which performs dry distillation yield experiment of fatty acid pitch Diagram showing equipment for adding fatty acid pitch with coal to tar on coal

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Coke oven 11 Coal feeding belt 12 Tar tank 13 Coarse light oil tank 14 COG holder 20 Carbonization retort 21 Heating electric furnace 22 Pipe 23 Secondary cracking heating furnace 24 Cooler 25 Gas cooler 25a, 25b Liquid component collection pot 26 Gas filter 27 Gas collection container 30 Tar tank 31 Pump

Claims (2)

  A method for producing coke, wherein the amount of fatty acid pitch added is 2.5 wt% or less when the fatty acid pitch is charged together with coal into a coke oven.   The method for producing coke according to claim 1, wherein the addition amount of the fatty acid pitch is 0.5 to 2.0 wt%.

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