AU2006219317B2

AU2006219317B2 - Process for producing binder for coke

Info

Publication number: AU2006219317B2
Application number: AU2006219317A
Authority: AU
Inventors: Toshihiro Aramaki; Yasuhiro Kobashi; Isao Mochida; Masaki Onozaki; Jun Oriyama; Masaaki Tamura; Shigeru Ueda; Teizaburo Yahata
Original assignee: Kobe Steel Ltd
Current assignee: Kobe Steel Ltd
Priority date: 2005-03-02
Filing date: 2006-03-02
Publication date: 2009-08-13
Anticipated expiration: 2026-03-02
Also published as: AU2006219317A1; WO2006093236A1; CN101163777B; CN101163777A

Description

1 DESCRIPTION METHOD OF PRODUCING COKING ADDITIVE FOR COKE TECHNICAL FIELD [0001] The present invention relates to a method of producing a coking additive for coke to be blended in coal for coke making so as to make up for the shortage of coking property. BACKGROUND ART [0002] With respect to raw material coal to be used for producing coke (hereinafter, referred to also as coal for coke making), it is indispensable to use bituminous coal having a coking property, which is referred to as strong coking coal. However, such coal for coke making as having a strong coking property is limited in its resources and is expensive, in comparison with steaming coal used for power plants. [0003] For this reason, in order to make the coal that is insufficient in the coking property applicable to the coal for coke making, a technique has been widely known in which coal-based or petroleum-based pitch is blended in the raw material coal as a coking additive so as to make up for the shortage of coking property.

2 The former coal-based pitch is coal tar pitch made from coal tar obtained by carbonization of coking coal, and as the latter petroleum-based pitch is known propane deasphalting asphalt (PDA), asphalt pitch (ASP) and the like. Since the petroleum-based pitch generally has high sulfur content and since it is inferior in the conformity with coal from the viewpoint of its chemical structure, the coal-based pitch is considered to be superior to the petroleum-based pitch. Various techniques of this kind have been proposed and those are too many to enumerate. (0004] On the other hand, another technique has been examined in which a coking additive is produced by using semi-bituminous coal and lignite (hereinafter, sometimes referred to as non-coking steaming coal) having a low coking property that is inexpensive and enormous in its resources. For example, a technique has been proposed in which in the presence of a disposable iron-based catalyst, steaming coal is hydrogenated at a temperature of 4200C or more under a high pressure of 70 atmospheres or more, and as its typical example, SRC-I process in the U.S. has been known by the following documents. Patent Document 1: JP-A No. 58-24301 3 Non-Patent Document 1: Steel Handbook, Vol. II, Iron making & Steel making, p212, published December 25, 1982. Any discussion of documents, acts, materials, devices, 5 articles or the like which has been included in the present specification is solely for the purpose of providing a context for the present invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common 10 general knowledge in the field relevant to the present invention as it existed before the priority date of each claim of this application. DISCLOSURE OF INVENTION 15 Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or 20 step, or group of elements, integers or steps. PROBLEMS TO BE SOLVED BY THE INVENTION (0005] In the above-mentioned SRC-I process, however, reaction is carried out at a high temperature under a high 25 pressure, the apparatus cost becomes high, furthermore, the hydrocracking reaction progresses in a high level, liquefied oils and hydrocarbon gases such as methane are generated as by-products, which causes decrease in the yield of a coking additive to a low level of about 50%. 30 The consumption of expensive hydrogen becomes increased, and additional cost will be required for the de-ashing process. For this reason, this method has not been practically applied commercially. 35 [0006] There is clearly a need to provide a novel method of producing a coking additive for coke in which steaming 826164_1.doc 4 coal having a low coking property can be desirably used as its raw material. MEANS TO SOLVE THE PROBLEMS 5 (0007] The present inventors recognise that the following three (3) needs exist for the method of producing a coking additive for coke from non-coking steaming coal: (1) reduction in the costs for production apparatuses; (2) reduction in the hydrogen consumption required for the 10 reaction; and (3) improvement of yield of the coking additive. The inventors of the present invention have extensively studied methods for simultaneously achieving these meeds, and found that these needs can be first achieved by using a two-stage thermal decomposition with 15 hydrogenation reaction using a hydrogenated heavy solvent; thus, the present invention has been completed. [0008] The present invention provides a method of producing a coking additive for coke production which is blended in a feed coal for coke making to improve coking 20 property, is characterized by that non-coking steaming coal is converted into a heavy component having a caking property through two-stage hydrogenation reactions in the presence of a hydrogenated heavy solvent by using a tubular reactor and a vessel reactor in this order. 25 [0009] The method of producing a coking additive for coke in the present invention is characterized by that the hydrogenated heavy solvent is at least one of the following; a heavy oil having an aromaticity index of 0.5 to 0.6 with a boiling point of 220 0 C to 540 0 C, and a 30 solvent fraction from a coke oven formed through processes in which heavy distillates having a boiling point of 220 0 C to 540 0 C, contained in coal tar that is generated upon dry-distilling the caking additive for coke blended in a coal for coke making, is hydrogenated to an aromaticity 35 index of 0.5 or less. 826164_1.doc 5 In one aspect, the present invention is directed to a method of producing a coking additive for coke to be blended in a coal for coke making so as to make up for the shortage of coking property to the coal for coke making, 5 wherein a non-coking steaming coal is subjected to two-stage hydrogenation reactions in the presence of a hydrogenated heavy solvent by using a tubular reactor and a vessel reactor in this order so as to be converted into a heavy 10 component having a coking property, a coal reaction product obtained is continuously withdrawn, and carbon dioxide and water are separated in a flash drum, the bottom oil in the bottom of flash drum is 15 fractionated in a vacuum distillation column, and then a coking additive is withdrawn from the bottom of the vacuum distillation column, wherein the hydrogenated heavy solvent is at least one of a heavy oil having an aromaticity index of 0.5 to 20 0.6 and a boiling point of 2200C to 5400C or a heavy oil in which heavy distillates, having a boiling point of 2200C to 540 0 C and contained in coal tar that is generated upon carbonizing a coking additive blended in a coal for coke making, are used as a material to be hydrogen-treated 25 to an aromaticity index of 0.5 or less. [0010] In a preferred embodiment, the method of producing a coking additive for coke in the present invention is characterized by that the reaction in the tubular reactor is carried out under conditions of a temperature of 3500C 30 to 4000C and a reaction time of 60 seconds to 300 seconds, and the reaction in the vessel reactor is carried out under conditions of a temperature of 3500C to 4000C and a reaction time of 10 minutes to 60 minutes, respectively. [0011] In a preferred embodiment, the method of producing 35 a coking additive for coke in the present invention is characterized by that the hydrogenated heavy solvent is 826164_1.doc 6 blended for the reaction at a content of 90% by mass to 40% by mass with rest of 10% by mass to 60% by mass of the non-coking steaming coal. [0012] In a preferred embodiment, the method of producing 5 a coking additive for coke in the present invention is characterized by that 1 part by mass or less of an iron based catalyst is blended for the reaction with respect to 100 parts by mass of a non-coking steaming coal. [0013] In a preferred embodiment, the method of producing 10 a coking additive for coke in the present invention is characterized by that a coke oven gas is fed to the vessel reactor for a reaction in an atmosphere of hydrogen and carbon monoxide under a pressure of 0.5 MPa to 1.5 MPa. 15 EFFECTS OF THE INVENTION [0014] In the method of producing a coking additive for coke in the present invention, a non-coking steaming coal is converted to a heavy component a coking additive through the two-stage hydrogenation reactions in the 20 presence of a hydrogenated heavy solvent so that it becomes possible to provide a novel desirable method of producing a coking additive for coke by the use of steaming coal having a low coking property as a raw material. 25 In accordance with the method of producing a coking additive for coke, the costs of the production apparatus are inexpensive and the consumption of hydrogen to be used in the reaction is small, so that it is possible to reduce the production cost and also to achieve a high yield of 30 the coking additive. BEST FORMATION FOR CARRYING OUT THE INVENTION [0015] The following description will discuss how to produce a coking additive for coke in accordance with the 35 present invention. 826164_1.doc 7 [0016] In the method of producing a coking additive for coke in the present invention, a non-coking steaming coal is used as a raw material and converted to a coking additive that is a heavy component having a coking 5 property by a two-stage thermal decomposing with hydrogenation reaction including a quick heating short time reaction in a tubular reactor as a first stage and a long-time reaction in a vessel reactor as a second stage. With this method, since a mild reaction temperature 10 is applied, an over decomposition reaction of the non coking steaming coal is restrained, and liquefied oils and hydrocarbon gases yields are well controlled. For this reason, the consumption of expensive hydrogen can be as lower as a level of 1 part by mass per 100 parts by mass 15 of non-coking steaming coal. In the above-mentioned reaction mechanism, since the most of by-products are carbon dioxide gas and water, it is possible to achieve not only a yield of the coking additive as high as about 80%, but also functions that are 20 as high as or higher than those of the conventional coking additive, with respect to all the items, such as the softening area, viscosity (melt viscosity), hydrogen donating property, dissolving power and carbonization yield, required as the performances of the coking 25 additive. [0017] Referring to a schematic drawing of producing processes shown in Fig. 1, the following description will 826164_1.doc 8 further discuss the method of producing a coking additive for coke regarding the present invention in more detail. [0018] A non-coking steaming coal as a raw material is fed into a tubular reactor 10 with a hydrogenated heavy solvent. At this time, the mixture, prepared by blending the hydrogenated heavy solvent in the range from 90% by mass to 40% by mass with the non-coking steaming coal in the range from 10% by mass to 60% by mass, preferably by blending the hydrogenated heavy solvent in the range from 65% by mass to 55% by mass with the non-coking steaming coal in the range from 35% by mass to 45% by mass, more preferably by blending the hydrogenated heavy solvent of about 60% by mass to with the non-coking steaming coal of about 40% by mass, is supplied to the tubular reactor 10. The hydrogenated heavy solvent is preferably heavy oil having an aromaticity index of 0.5 to 0.6 and a boiling point of 220*C to 540*C. The hydrogenated heavy solvent may be the coal tar derived heavy oil in which heavy distillates, preferably having a boiling point of 220'C to 540 0 C and contained in coal tar that is generated by carbonization with a coking additive in a coke oven, are hydro-treated preferably to have an aromaticity index of 0.5 or less. Alternatively, the hydrogenated heavy solvent may be a mixture of these heavy oils. When 1 part by mass or less of a fine-powder 9 disposable iron-based catalyst is added for reaction to 100 parts by mass of a non-caking steaming coal, the hydrogenation reaction progresses more smoothly. With respect to the applicable iron-based catalyst, among iron ores that are inexpensive, for example, pyrite (main component FeS 2 ), hematite (main component Fe 2 0 3 ) and limonite (main component FeOOH) are listed, and among synthesized catalysts, for example, a-oxy iron hydroxide (aFeOOH) and y-oxy iron hydroxide (y-FeOOH) are listed. [0019] In the tubular reactor 10, preferably, a high speed heating process is carried out under conditions of a temperature of 350 0 C to 400 0 C and a reaction time of 60 seconds to 300 seconds, more preferably, a temperature of 380 0 C to 400 0 C and a reaction time of about 200 seconds. The mixture from the outlet of the tubular reactor 10 is heated to a temperature near the thermal decomposing temperature of the steaming coal in the vessel reactor 12 under sufficient reaction conditions of preferably a temperature of 3500C to 4000C and a reaction time of 10 minutes to 60 minutes, more preferably, a temperature of 3700C to 3900C and a reaction time of about 30 minutes. Thus, carbon dioxide gas and water are generated. Thermally cracked fragments, generated at this time, are made to react with nascent active hydrogen from the hydrogenated heavy solvent to cause a thermal cracking 10 hydrogenation reaction. In the case when a coking additive producing apparatus (range indicated by a solid line in Fig. 1) is installed adjacent to a coke oven 14, coke oven gases (COG) generated from coke oven 14 can be used as hydrogen sources at low pressure for the vessel reactor 12. In this case, the reaction is preferably carried out in an atmosphere of hydrogen and carbon monoxide under a pressure of 0.5 MPa to 1.5 MPa. A coal reaction product, obtained in the vessel reactor 12, is continuously withdrawn, and carbon dioxide and water are separated in a flash drum 16. [0020] After the separation of carbon dioxide and water, the bottom oil in the bottom of flash drum 16 is fractionated in a vacuum distillation column 18, under, for example, conditions of a column-bottom temperature of 310*C to 350 0 C and a pressure of 5 kPa to 15 kPa, and a coking additive is withdrawn from the bottom of the vacuum distillation column 18. The vacuum heavy oils are fed to a solvent hydrogenation reactor 20, hydrogenated by hydrogen, and recycled and used as the hydrogenated heavy solvent. In the case when a coking additive producing apparatus is placed adjacent to a coke oven 14, hydrogen including in coke oven gas (COG) can be utilized for the hydrogenation 11 of the vacuum heavy oils. [0021] The coking additive, obtained from the vacuum distillation column 18, has a boiling point of 500 0 C or more under atmospheric pressure and a softening point of 150*C or more, and characteristics close to those of hard pitch. Therefore, in the case when the coking additive producing apparatus is placed adjacent to the coke factory, the hot coking additive from the vacuum distillation column 18, in its hot fused state, can be added to coal to save energy. In this case, however, another apparatus which kneads the hot coking additive and coal particles is required to make the two components well mixed. In other words, after having been kneaded with steaming coal in the kneader 22 without cooling and solidifying processes, the coking additive is blended with coal in the mixer 24 and fed into the coke oven 14 which results in such effects as the rate of use of inexpensive steaming coal can be increased and the coke strength can be improved. In contrast, in the case when the coking additive producing apparatus is not placed adjacent to a coke factory, after the coking additive has been cooled and solidified, this needs to be transported to the coke factory, and pulverized into an appropriate particle size, and after having been blended with steaming coal in the mixer 24 without passing through the kneader 22, these are fed to the coke oven 14.

12 Thereby, the coking property improving effect can be achieved. In other words, there are provided such effects as the rate of use of inexpensive steaming coal can be increased and the coke strength can be improved. 5 [0022] Since the coking additive producing apparatus can utilize hydrogen generated at the nearby coke factory as described above, a hydrogen generator is not required. Moreover, coal tar which is generated in the coke factory can be used for a raw material for a hydrogenated heavy 10 solvent. In the case when the coking additive producing apparatus is placed adjacent to the coke factory, since the coke factory provides coal handling facilities, various 15 advantages, such as not necessary to newly prepare apparatuses used for landing, transporting and blending coal, can be obtained. EXAMPLES 20 [0023] By using Tanito Harum coal (sub-bituminous coal, mined in Indonesia) as a raw material, coking additives were produced at typical reaction temperatures, 370*C and 3900C of the second stage. Reaction conditions of Example 25 1 and Example 2 are shown in Table 1, and the yield and the reaction products etc. are shown in Table 2 respectively. "daf" in Table 2 means "dry ash free (moisture-ash-free base)".

13 [0024] [Table 1) Example Example 1 2 Reaction 1st stage ( 0 C) 380 400 temperature 2nd stage (0C) 370 390 Reaction pressure (MPa) 0.7 1.2 Reaction time 1st stage (sec) 200 200 2nd stage (min) 30 30 Iron-based catalyst*' (wt%) - 1.0 fa*i) of hydrogenated heavy - 0.5 0.5 solvent* 2 ) Conc. of non-coking steaming (wt%) 40 40 coal in coal slurry *1) Iron-based catalyst: parts by mass on the dry base (dried natural limonite) with respect to 100 parts by mass 5 of non-coking steaming coal (use of ultra-fine pulverized particles of natural limonite ore produced in Indonesia supplied by Kobe Steel Ltd.; mean particle size 0.5 micro meter). *2) Hydrogenated heavy solvent: boiling point of 220 10 5400C. *3) The "fa" represents aromaticity index. [0025] [Table 2] Coking additive (wt%/daf) 81.9 60.2 Carbon dioxide gas- CO 2 (wt%/daf) 6.9 7.2 Water' H 2 0 (wt%/daf) 7.0 8.0 Hydrocarbon gas- C1-C4 (wt%/daf) 1.0 2.1 Oil content (wt%/daf) 4.1 24.8 Hydrogen consumption (wt%/daf) 0.9 2.3 15 [0026] Comparing with 390 'C of the second stage reaction temperature in Example 2, 370'C of the second stage reaction temperature in Example 1 makes lower hydrogen consumption, slower de-carbon dioxide gas and dehydration 14 reactions, which results in increase in the yield of the coking additive. Table 3 shows ultimate analysis of the Tanito Harum coal used as raw coal and the generated coking additive 5 respectively. Table 4 shows test results of the drum strength index for cokes prepared by the test coke oven under the prescribed condition using normal coal blend and 6wt% of the coking additive added to the same coal blend. 10 Comparing with 390 0 C of the second stage reaction temperature in Example 2, 370*C of the second stage reaction temperature in Example 1 brings slightly higher hydrogen and oxygen content, no difference is observed in the coke strength. 15 [0027] [Table 3] Coking Coking Tanito Harum additive additive coal (Examplel) (Example2) C (wt%/daf) 75.9 89.0 89.7 H (wt%/daf) 5.8 5.3 5.0 N (wt%/daf) 1.8 1.0 1.0 S (wt%/daf) 0.2 0.2 0.3 0 (wt%/daf) 16.3 4.5 4.0 (0028] 15 [Table 4] No cooking additive Coking additive Coking additive (Examplel) (Example2) DI (150/15)* 83.5 85.6 86.0 * DI (150/15): rate of particle size of 15mm or more after 150 rotations of drum BRIEF DESCRIPTION OF THE DRAWINGS [0029] Fig. 1 is a schematic drawing for producing a coking additive for coke in accordance with the present invention. REFERENCE NUMERALS [0030] 10 Tubular reactor 12 Vessel reactor 14 Coke oven 16 Flash drum 18 Vacuum distillation column 20 Solvent hydrogenation reactor 22 Kneader 24 Mixer

Claims

1. A method of producing a coking additive for coke to be blended in a coal for coke making so as to make up 5 for the shortage of coking property to the coal for coke making, wherein a non-coking steaming coal is subjected to two-stage hydrogenation reactions in the presence of a hydrogenated heavy solvent by using a tubular reactor and a vessel 10 reactor in this order so as to be converted into a heavy component having a coking property, a coal reaction product obtained is continuously withdrawn, and carbon dioxide and water are separated in a flash drum, 15 the bottom oil in the bottom of flash drum is fractionated in a vacuum distillation column, and then a coking additive is withdrawn from the bottom of the vacuum distillation column, wherein the hydrogenated heavy solvent is at least 20 one of a heavy oil having an aromaticity index of 0.5 to 0.6 and a boiling point of 220*C to 540*C or a heavy oil in which heavy distillates, having a boiling point of 220 0 C to 5400C and contained in coal tar that is generated upon carbonizing a coking additive blended in a coal for 25 coke making, are used as a material to be hydrogen-treated to an aromaticity index of 0.5 or less.

2. The method of producing a coking additive for coke according to claim 1, wherein the reaction in the 30 tubular reactor is carried out under conditions of a temperature of 3500C to 4000C and a reaction time of 60 seconds to 300 seconds, and the reaction in the vessel reactor is carried out under conditions of a temperature of 3500C to 4000C and a reaction time of 10 minutes to 60 35 minutes, respectively. 17

3. The method of producing a coking additive for coke according to claim 1, wherein the hydrogenated heavy solvent is blended for the reaction at a content of 90% by mass to 40% by mass with respect to 10% by mass to 60% by 5 mass of the non-coking steaming coal.

4. The method of producing a coking additive for coke according to any one of claims 1 to 3, characterized in that 1 part by mass or less of an iron-based catalyst is blended for the reaction with respect to 100 parts by 10 mass of a non-coking steaming coal.

5. The method of producing a coking additive for coke according to any one of claims 1 to 4, wherein a coke oven gas is fed to the vessel reactor so as to be subjected to a reaction in an atmosphere of hydrogen and 15 carbon monoxide under a pressure of 0.5 MPa to 1.5 MPa.