JPS61285286A - Carbonization of coal - Google Patents

Abstract

PURPOSE:To obtain high-quality blast furnace coke, by adding a small amount of a radical controlling agent consisting of a specific aromatic compound and naphthenic compound together with a caking filler to stock coal and carbonizing the coal. CONSTITUTION:Stock coal is compounded with (A) a radical controller consisting of (i) an aromatic compound having hydroxyl group, secondary amino group and/or (di)azo group and/or (ii) a naphthenic compound and (B) a caking filler and the coal mixture is carbonized. The amount of the component A is 1-0.005wt% based on the stock coal and 10-0.05% based on the component B. Preferably, the aromatic compound having hydroxyl group is hydroquinone or t-butylcatechol, the secondary amino compound is phenyl-alpha-naphthylamine, etc., the azo compound is azobenzene, etc., and the naphthenic compound is decalin or tetralin.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is used in the coke manufacturing industry, which carbonizes coal to produce coke and its by-products. The present invention relates to a method for producing high-quality blast furnace coke or advantageously producing by-products by adding a small amount of radical control agent together with a caking filler.

[Conventional technology]

The quality of blast furnace coke is determined by drum strength (DI: J
IS 2151) In other words, the ring strength is high and at the same time,
It is required that the C02 reactivity due to carbon dioxide gas at high temperatures (CRI: Coke Circular, Record, 82 (1974)) is low, and the small C02 reaction reactivity (C8R: Coke Circular, η, 82 (1974)) is high. has been done.

Methods to achieve this purpose include adjusting the coal type and blend of charging coal, adjusting operating conditions such as humidity control, viscosity control, and carbonization temperature, and adding caking fillers and molding. A number of methods have been taken, including methods of blending charcoal.

However, none of the above-mentioned methods were necessarily satisfactory due to increased manufacturing costs or equipment problems.

Therefore, the present inventor first added various reaction inhibitors (
Patent Application No. 58-248 to propose a coal carbonization method that can achieve the quality required for blast furnace coke even when using coal with poor coking properties by adding a small amount of a small amount of a radical control agent). .323 and patent application 1982-22
No. 0.564>. This method of adding a radical control agent artificially controls the type and amount of radicals that are generated during carbonization of coal and has a significant effect on coke production, thereby reducing coal that has poor coking properties. The aim is to produce high-quality coke for blast furnaces and to advantageously produce by-products using charging coal mixed with a relatively large amount.

[Problem that the invention seeks to solve]

However, this method of adding a radical control agent has the advantage that it requires no special equipment by simply selecting the appropriate chemical, and the manufacturing cost is low. However, when investigating various types of coal, Depending on the type of coal, the effect may be significant or insufficient, and in some cases negative effects may occur. As a result, a problem arose in that the effect of improving coke properties varied depending on what kind of coal was mixed in the charging coal and in what proportion.

Therefore, the present inventor conducted the following basic experiment in order to investigate the cause of the problem that the effect of improving coke properties varies in the method of adding a radical control agent.

In other words, first, a certain amount of various radical control agents was added to a particular charged coal, and coke was produced under certain conditions using a small electric carbonization furnace. D I 150/15,
CRI, C8R, micro strength (MS I; JIS
H0104, J, Iron and 5teel
In5t, 136.49 (1937)) and CO2 gasification reactivity (R1; JIS K 2151).

Next, we measured the width of the softening and melting temperature range (m degree range ℃) in flow trace measurements using a Gieseler blast meter, which is closely related to coking ability, for single coals with various degrees of coalification. The difference between when 0.1% by weight of the agent was added and when it was not added was calculated, and the value of this difference is plotted on the vertical axis, and the degree of coalification (using Gotrinit reflectance R8 as an index) is plotted on the horizontal axis. The effect of the type of radical control agent used and the degree of coalification on the effect of adding the radical control agent was investigated from the obtained graph (Figure 1).

As is clear from Figure 1, the results have little to do with the type of radical control agent used, but are largely dependent on the degree of coalification of the coal used. Reflectance (R6) 0.8-1.35
It was found that the softening and melting range expands in the range of (33 to 22% volatile content), that is, the range of fluidity, and that the effect is negative in other ranges. The reflectance of vitrinite (Ro) used as an index of the degree of coalification is the optical reflectance of vitrinite in coal components, and is closely related to the volatile content determined by conventional industrial analysis and the carbon content determined by elemental analysis. It shows a correlation and has been widely used in recent years as a method of expressing the degree of coalification.

Furthermore, hydroquinone and azobenzene were added in an amount of 0.1% by weight each as a radical control agent to single coals of various degrees of coalification and carbonized, and the microstrength (MS) of the coke obtained was
I) and CO2 gasification reactivity (R1), and find the difference between MSI and R1 of coke produced without additives.This difference is plotted on the vertical axis, and the degree of coalification is plotted on the horizontal axis. The reflectance (Ro) and volatile content (VM) of vitrinite were plotted and the graph shown in FIG. 2 was obtained.

From the results shown in Figure 2, an improvement in MSI and a decrease in R1 are observed in the range of volatile content (VM) of 32 to 21% or reflectance of vitrinite (Ro) of 0.90 to 1°35, while in other ranges, It turned out to be unacceptable.

Therefore, from the above experimental results, it can be concluded that (1) the effect of adding a radical control agent is almost the same regardless of the type of radical control agent used as long as the charged coal is the same; The effect on the softening and melting temperature range when added is influenced by the degree of coalification of the charging coal used, and the reflectance (Ro) of vitrinite is 0.8 to
The micro strength (MSI) and CO2 gasification reactivity (R1 ) is affected by the degree of coalification of the charging coal used, and the reflectance (Ro) of vitrinite ranges from 0.9 to 1°35 (volatile content: 32 to 21°).
% range), and in other ranges it actually decreased.

By the way, there are some unknown points about the action of radical control agents added to coal, but like antioxidants, polymerization inhibitors, polymerization initiators, etc. used in ordinary polymeric organic compounds, they can be added to coal at room temperature or at room temperature. Unlike when it is used at a relatively low temperature of 200°C or less, it is used at a high temperature, so it seems that various separate reactions occur. ii) Hydrogen transfer action, which acts as a donor to give hydrogen to coal; ii) Hydrogen transfer action, which mediates the taking of hydrogen from adjacent molecules and transferring it to a portion of coal with high hydrogen-accepting capacity; 1ii) Coal-specific action. or a radical inhibitor that stops polymerization due to radicals generated during thermal decomposition, and iv) a polymerization initiation or polymerization acceleration effect contributed by a control agent from which hydrogen has been extracted or radicals generated by decomposition during heating. It seems that each of these effects occurs simultaneously or sequentially.

If we consider this effect of the radical control agent added to coal together with the knowledge obtained from the above experiment, we will find that:
The above range of coalification degree, that is, the reflectance of vitrinite (
Ro) Coal other than fluid caking coal in the range of 0.8 to 1.35 or volatile content of 33 to 21% has a larger hydrogen accepting capacity than hydrogen donating capacity, and is added during carbonization of coal to control radicals. Hydrogen in the agent is extracted and active radicals are generated, and these radicals promote undesirable polymerization reactions.As a result, the effect of improving coke properties when carbonizing coal by adding a radical control agent varies. considered to be a thing.

[Means and effects for solving the problem] The present invention was devised in view of this point of view, and when carbonizing coal with the addition of a radical control agent, the hydrogen contained in the charged coal to be used is reduced. By adding a caking filler at a predetermined ratio that can supplement the supply capacity, the effect of adding a radical control agent during carbonization of coal is reliably brought out, and the quality of coke produced is dramatically improved. The present invention also provides a method for carbonizing coal that can advantageously produce by-products.

That is, the present invention provides a method for producing coke and/or its by-products by adding a radical control agent to charged coal and carbonizing it, in which a hydro group, a secondary amino group, an azo group, and/or a diazo group is added as the radical control agent. One type or a mixture of two or more selected from aromatic compounds having a group or naphthenic compounds is used, and a caking filler is added in combination, and the radical control agent is added to the charged coal in an amount of 1 to 10%. 0.0
05% by weight or 10 to 0.0 based on the above caking filler
This is a carbonization method for coal used in a range of 5% by weight.

The radical control agents used in the present invention include aromatic compounds having a hydro group such as hydroquinone and t-butylcatechol, phenyl-α-naphthylamine, phenyl-β-naphthylamine, or N,N'-dimethylphenylenediamine. aromatic compounds having a secondary amine group, aromatic compounds having an azo group such as azobenzene, aminoazobenzene or hydroxyazobenzene, aromatic compounds having a diazo group such as azoic diazo salts, aromatic compounds having a diazo group such as decalin or tetralin. Examples include naphthenic compounds, which can be used alone or in combination of two or more. These radical control agents are not necessarily hydrogen-donating per se, but have the ability to act as a carrier to extract hydrogen from the atmosphere or adjacent molecules and provide it to the coal;
In other words, it is necessary to have hydrogen transfer ability. These radical control agents are used to improve the coal type and blending ratio of charged coal, the purpose of using this radical control agent, i.e., to improve coke DI and C8R, or to improve the yield and characteristics of tar. It is selected as appropriate depending on whether the purpose is to improve or not.

Further, the caking filler to be added in combination with the radical control agent may be any one that can compensate for the caking properties of coal, and preferably one that can donate hydrogen to coal during carbonization. Such caking fillers include, for example, coal-based tar, pitch, various tar distillation residues, tar sludge, etc., heavy oil from coal liquefaction, pitch, etc., petroleum-based pitch, heavy oil, Examples include various distillation residues, cracked residual oils, etc., ethylene bottoms, ethylene tar, styrene tar, etc. derived from petroleum refining, heavy residual oils of tar sand oil and oil shale, and bituminous materials such as pitch.

There are no particular restrictions on the method of adding the radical agent or caking filler. For example, regarding the method of adding the radical control agent, if it dissolves in the caking filler, it may be added after being dissolved in the caking filler; If it is difficult to prepare, mix it in powder form or dissolve it in another solvent to make it into a liquid and add it.

In addition, regarding the method of adding the caking filler, it may be simply kneaded with the charged coal and mixed. Alternatively, a briquette partial charging method in which briquette coal and powdered coal are mixed and charged, or When carbonizing coal by carbonizing only charcoal to produce molded coke, it may be added as a molding binder or as a part of the molding binder used in producing the molded coal, and furthermore, drying When a dustproof binder is used as a dustproof measure during charging of coal, it may be added as part or all of it.

The amount of the radical control agent added is 1 to 0.005% by weight, preferably 0.005% by weight, based on the normally used charged coal.
1 to 0.01 weight maximum or 10 to the above caking filler
It is used in an amount of 0.051% by weight, preferably 1% to 0.1% by weight. If too much of this radical control agent is added, not only will the cost increase, but if there is not enough hydrogen to be transferred from the surroundings to the coal, it will promote polymerization and have the opposite effect, and if it is too little, the reaction rate will be reduced. As a result, the desired effect cannot be achieved within the coking time.

〔Example〕

Hereinafter, the method of the present invention will be specifically explained based on Examples.

Example 1 Poor quality coal 3 which is considered unsuitable for producing coke for blast furnaces
Coal powder containing 0% heavy weight coal, 6% by weight of coal-based soft pitch (SOP) as a caking filler, various radical control agents, no additives (No, 1, SOP only), phenyl-β-naphthylamine (NO ,2), phenolic antioxidant (
Ciba Geigy product name Nilganox>50% by weight
and [-butylcatechol 25% by weight and hydroquinone 2
5% by weight mixture (No. 3), azo dye (No.
4) 50% by weight of azoic diazonium chloride
and azoic diazonium sal 777,650 ffi%
A mixture with (N.

, 5), 2% by weight of Decalin (No. 6) is added to this coal-based soft pitch (0.03% of weight based on coal) to produce briquette coal, and 25% by weight of this briquette coal is added to the raw material powder coal. A charging amount of 80 kg of this charging coal was prepared by blending 80 kg of charging coal.
The coke was charged into a small electric carbonization furnace of 0 Ky/charge and carbonized at a maximum temperature of 1050°C, and the coke properties, drum strength (DI 150/15),
Small C02 post-reaction strength (C8R), CO2 reactivity (CR)
I), microintensity (MSI) and Co2 gasification reactivity (R1) were measured. The results are shown in Table 1.

Table 1 As is clear from the results in Table 1, the mechanical strength, DI and MSI hardly change due to the addition of the radical control agent, whereas the CO gasification reactivity (RI
) decreased, and the strength after CO2 reaction (C8R) significantly improved. Practically speaking, DI and C8R are exclusively used as quality evaluation indicators for blast furnace coke, but the fact that DI did not change much and only C8R improved means that other conditions remain constant and the chemical This shows that only the physical properties have changed and improved. This was also confirmed by changes in the optically anisotropic structure of the coke observed by microscopic observation of the coke obtained.

Example 2 As a caking filler, petroleum-based propane was removed from asphalt (
(petroleum-based PDA) 8% by weight, no additives as radical control agents (NO, 1, petroleum-based PDA only), phenyl-
β-naphthylamine (No. 2), hydroquinone (No. 7), azobenzene (No. 8) and tetralin (SO19) were used, and these radical control agents were added at 5% by weight (vs. 0.0%) based on petroleum-based PDA. 1% by weight
) Coke was produced in the same manner as in Example 1 above, except that coke was used, and the properties of the coke were examined. The results are shown in Table 2.

〔Effect of the invention〕

According to the present invention, by using a caking filler and a less aggressive radical control agent in combination, the RI of the produced coke is lowered even for charged coal containing a large amount of poor quality coal. It is possible to improve coke properties such that C8R is significantly improved, and to obtain high quality blast furnace coke. This means that a large amount of inferior quality coal can be used as coking coal for coke for blast furnaces, and its economic effects are extremely high in modern times when production of high quality coking coal for coke is scarce.

[Brief explanation of drawings]

Figure 1 shows the results of basic experiments that led to the present invention, and shows the difference in degree of coalification (reflectance R8 of vitrinite) and softening and melting temperature range (6°C) when various radical control agents were used.
〉 Figure 2 is a graph showing the relationship between radical IIJt
Difference in coalification degree (vitrinite reflection pR8 and volatile content VM) and micro-intensity (ΔMSI) and C when hydroquinone and azobenzene are used as II agents
FIG. 2 is a graph similar to FIG. 1 showing the relationship with o2 gasification reactivity (ΔR1). Patent applicant Nippon Steel Chemical Co., Ltd. Representative Patent attorney Katsuo Naruse
Figure 1 Coal LM (Bit ν Nint et al. J! 1 square meter 0) Figure 2

Claims (2)

[Claims] (1) In a method of adding a radical control agent to charged coal and carbonizing it to produce coke and/or its by-products, the radical control agent has a hydro group, a secondary amino group, an azo group, and/or a diazo group. One type or a mixture of two or more selected from aromatic compounds or naphthenic compounds is used, and a caking filler is added in combination, and the radical control agent is added at a rate of 1 to 0.005 to the charged coal. A method for carbonizing coal, characterized in that it is used in an amount of 10 to 0.05% by weight based on the caking filler. (2) The aromatic compound having a hydro group is hydroquinone or t-butylcatechol, and the aromatic compound having a secondary amino group is phenyl-α-naphthylamine, phenyl-β-naphthylamine or N,N'-dimethylphenylenediamine and the aromatic compound having an azo group is azobenzene, aminoazobenzene or hydroxyazobenzene, the aromatic compound having a diazo group is an azoic diazo salt, and the naphthenic compound is decalin or tetralin. The method for carbonizing coal according to item 1.