Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
  • C10B15/00—Other coke ovens
  • C10B15/02—Other coke ovens with floor heating
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
  • C10B45/00—Other details
  • C10B45/02—Devices for producing compact unified coal charges outside the oven
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
  • C10B57/00—Other carbonising or coking processes; Features of destructive distillation processes in general
  • C10B57/04—Other carbonising or coking processes; Features of destructive distillation processes in general using charges of special composition
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
  • C10B57/00—Other carbonising or coking processes; Features of destructive distillation processes in general
  • C10B57/04—Other carbonising or coking processes; Features of destructive distillation processes in general using charges of special composition
  • C10B57/045—Other carbonising or coking processes; Features of destructive distillation processes in general using charges of special composition containing mineral oils, bitumen, tar or the like or mixtures thereof

Definitions

• the invention relates to a process for producing metallurgical coke from petroleum coke generated in crude oil refineries, by coking in “non-recovery” or “heat-recovery” coking ovens, starting from petroleum coke obtained or generated in crude oil refineries and possessing from the outset a volatiles content of 15 to 19 weight percent and an ash fraction of up to 2 weight percent, this petroleum coke being introduced in densified form into a coking oven of “non-recovery” or “heat-recovery” construction for the purpose of cyclical coking, said oven being equipped with at least one externally heated burner, so that the primary heating space or the secondary heating space below the coking oven chamber, or both, are heated to a temperature of between 1000° C.
• the invention also relates to a coking oven which is constructed according to the “non-recovery” or “heat-recovery” coking ovens principle and which comprises a primary heating space which is equipped with burners which heat the primary heating space.
• the products of the processing of mineral oil and crude oil in refineries to form crude oil products include not only the desired products but also one known as petroleum coke, which is formed from high-boiling residues in distillation operations, reforming steps, hydrogenation processes, and purifying operations in a crude oil refinery.
• This petroleum coke consists typically of more than 88 weight percent carbon, with a volatile constituents (VOC) content of 8 to 12 weight percent.
• VOC volatile constituents
• This petroleum coke is only of minor economic interest, possessing properties which are unwanted in relation to numerous value-raising operations, such as a low CSR strength and a high CRI reactivity, for example, and for that reason finding no suitable consumer markets.
• Petroleum coke is used frequently in niche applications such as, for example, metallurgy for producing electrodes.
• the use of petroleum coke in iron and steel technology, i.e., for example, as a reducing agent in a blast furnace operation for producing pig iron, is not possible, since the strength of the petroleum coke is insufficient for use in a blast furnace, Additionally) known is the admixing of fractions of petroleum coke to bituminous coal mixtures, but the admixed fraction of the petroleum coke is limited to orders of magnitude of less than 10 weight percent, owing to the low quality of the blast furnace coke produced from it.
• a further problem with petroleum coke are impurities which come from the processing of the crude oil, and which have accumulated in the petroleum coke in the course of its removal.
• Impurities frequently encountered in the petroleum coke are, for example, vanadium, nickel, sulfur, silicon, iron, or titanium.
• the vanadium content of petroleum coke fractions can be up to 0.17 wt %, the nickel content up to 0.04 wt %, and the sulfur content up to 5 wt %.
• a consequence of these impurities is that the petroleum coke also cannot be used directly for heating purposes, since to do so would pollute the environment.
• Another characteristic of petroleum coke is that of having a lower flame temperature than blast furnace coke or coal. hi relation to its use :as a fuel, and its handling, this is an undesirable feature, ruling out the possibility of using it for numerous further-processing Operations. Possibilities are therefore sought fur providing an economic possibility for use of petroleum coke.
• the consequence of the fluctuating proportion of volatile constituents is that the use in a coking oven is difficult to control, owing to the substantially incalculable heating properties arising from the volatile constituents.
• the main fraction of the petroleum coke generated in refineries has a very low fraction of volatile constituents, of less than 19 weight percent, with the consequence that, if used in a “non-recovery” or “heat-recovery” coking oven, the coke is unsuitable for maintaining a self-supporting combustion—and hence coking—process.
• the coking operation would then conic virtually to standstill after a number of coking cycles, since the heat generated by combustion of the volatile constituents during coking, and stored in the refractory material of the oven, is no longer sufficient to keep the oven temperature at the required high figure of more than 1000° C. during the subsequent batches.
• a further difficulty affecting its coking is that petcoke exhibits very high swelling pressures in the course of the coking procedure, attributable to the presence therein of low-boiling volatile constituents. These constituents lead during the coking procedure to a substantial increase in the volume of the cake of coke, amounting virtually to an inflation. It is therefore not possible to coke petroleum coke in a conventional coking oven, since the walls of a coking oven chamber would be damaged in the course of the coking procedure, as a result of the increase in volume of the petroleum coke cake.
• WO0010914 A1 One possibility for the workup and further use of petcoke is given by WO0010914 A1.
• the teaching provides a process for subjecting petcoke from crude oil refineries, which is obtained from a petcoke precursor material from mineral oil, to a thermal cracking operation, at sufficiently high temperature, and for a sufficiently long time period at a sufficient pressure, to furnish a petcoke which contains a diminished and precision-adjustable volatiles content of 13 to 50 weight percent.
• the process moreover, discloses a possibility for desalting the petcoke, to remove the metallic impurities it contains.
• the teaching also discloses a possibility for taking back the sulfur impurities in the petcoke to a lowered and environmentally acceptable fraction, by means, for example, of adding desulfurizing agents to a fluidized bed.
• the process provides an opportunity to provide petcoke fractions having a. very precision-determinable content of volatile constituents and of impurities.
• Petcoke fractions having a volatiles fraction of 15 to 25 weight percent are referred to here as petroleum coke but have also been dubbed “petroleum coal”, since their properties resemble those of conventional bituminous fat or forge coals.
• the object is to provide a process which affords petroleum coke with a fraction of 15 to 19 weight percent of volatile constituents and of an increased fraction of impurities, utilizes it for coking on an industrial scale, and provides therefrom a coke which possesses an increased strength and a low reactivity, and which is suitable for use as metallurgical coke.
• the present invention achieves this object by means of a process which presents petroleum coke having a known volatile constituents content of 15 to 19 weight percent and a known ash fraction of up to 2 weight percent, and then carries out coking of this petroleum coke, in densified form, under regular conditions, with temperatures in the heating chambers between 1000° C. to 1550° C., within a time period of 120 hours, in a “non-recovery” or “heat-recovery” coking oven, to give metallurgical coke, the oven being equipped with at least one burner for heating the primary heating space, formed by the has space present in operation above the petroleum coke cake, or for heating the secondary heating space, below the coking oven chamber, or both.
• the volatiles content and the ash content of the petcoke are determined by analysis prior to coking, it being immaterial whether the analysis is carried out on the coking oven plant site or on the site of the petroleum coke supplier. All that is important for performance of the process of the invention is that a petroleum coke is presented that has a known volatile constituents content, the range to be complied with being at least 15 weight percent and not more than 19 weight percent.
• Claimed in particular is a process for producing metallurgical coke from petroleum coke obtained in the crude oil processing industry, where
• Coking ovens of the non-recovery or heat-recovery type with primary and secondary heating spaces are known to the person skilled in the art of coking technology. This type of construction is described comprehensively by way of example in the article by Walter Buss et al., “Thyssen Still Otto/PACTI Non-recovery coke making system”. Iron and Steel Engineer, Association of Iron and Steel Engineers, Pittsburgh, USA, Volume 76, No. 1. January 1999, pages 33-38.
• a coking oven battery of coking ovens suitable for the coking of carbonaceous feedstocks with high swelling pressures is exemplified by WO2011107198A1. In the course of the heating procedure, the cake of petroleum coke reaches an estimated temperature of 900 to 1100° C.
• the petroleum coke is heated in such a way as to produce a coke of the desired quality, with the fraction of volatile constituents in the petroleum coke ascending from the batch in the form of crude coking gas.
• Part of these outgassed constituents is combusted substoichiometrically for heat generation at least occasionally in the primary heating space, initially with addition of air.
• the partly combusted offgas mixture is then taken off via the lateral gas channels of the coking oven chamber, and combusted completely by further combustion in the secondary heating space.
• the volatiles fraction present in the petroleum coke therefore, the petroleum coke is heated from below as well with the consequence that. with the exception of the side door regions, the cake of petroleum coke is heated from all sides and a uniform quality of coking is obtained.
• the quality of the coke obtained can he determined as described, giving CSR strengths of at least 44% and a CRI reactivity of less than 33%.
• the prerequisite is the use of a petroleum coke batch which possesses a volatiles content of 15 to 19 weight percent and an ash fraction of less than 2 weight percent, based on the water-free and ash-free petroleum coke batch.
• the use of a petroleum coke whose volatile constituents content is determined with greater precision is also possible.
• the volatiles content of the petroleum coke is 16 to 18 weight percent. As a result, the operation can be controlled more effectively.
• the petroleum coke cake can in principle be heated from all sides, thereby attaining the desired temperature.
• the heating is performed in the coking oven such that the burner flame is introduced horizontally into the gas space over the petroleum coke batch, referred to as the primary heating space.
• at least one burner pipe is situated in the wall above the coking oven chamber door, this pipe being fed with a hot gas or combustion gas by a burner and opening out through an opening in the gas space above the petroleum coke, thereby heating this space with hot gas.
• the horizontal arrangement of the burner pipes above the batch ensures that the inflowing gas flows into the primary heating chamber above the petroleum coke cake and, as a result, direct contact between the coke surface and the combustion air, and hence unwanted burnoff of feed coke or product coke, is lessened.
• a vertical distance of more than 100 mm is established between the burner pipe introduced and the top edge of the batch, so that the top layers of petroleum coke are not combusted.
• the heating may be adjusted with the aeration and pressure regulation of the coking oven chamber, for example, in such a way an overpressure of 0.01 to 20 mbar is established in the coking oven chamber. This can be achieved by corresponding regulation of the burner and of the aeration shutters.
• the heating is adjusted with the aeration and pressure regulation in such a way that an overpressure of 0.1 to 10 mbar is established in the coking oven chamber.
• the coking oven chamber can be heated using natural gas as heating gas, for example.
• natural gas for example.
• liquid gas, coking oven gas, blast furnace top gas, or converter gas as heating gas.
• the choice of an appropriate heating gas is dependent on a variety of factors, such as on availability, for example.
• the content of volatile constituents in the petroleum coke introduced is important in order to achieve the desired CSR strength and CRI reactivity of the coke product, and in order to ensure a desired heatability with the heating performance through the outgassing constituents.
• the petroleum coke mixture prior to grinding, is mixed with bituminous coal as adjuvant, so that the volatiles content is between 19 and 25 weight percent, based on the dry charge mixture.
• the petroleum coke mixture prior to grinding, is mixed with bitumen as adjuvant, so that the volatiles content is between 19 and 25 weight percent, based on the dry charge mixture.
• the petroleum coke mixture prior to grinding, is mixed with an oil grade as adjuvant, so that the volatiles content is between 19 and 25 weight percent, based on the dry charge mixture.
• the coke product obtained as a consequence possesses a CSR strength of more than 44% and a CRI reactivity of less than 33%.
• the petroleum coke employed possesses an ash fraction which is below 2 weight percent, In general this is just enough to protect the petroleum coke from excessive burnoff by combustion in the course of coking. In order to ensure sufficient economics of the process. however, it is frequently necessary to take additional measures against unwanted burnoff of the petcoke. For this purpose it is also possible to select a somewhat higher volatile constituents content if the petroleum coke is admixed with adjuvants which possess an inhibiting effect on the combustion of the petroleum coke.
• the ash fraction as well may be selected at a higher level if the petroleum coke is admixed with an adjuvant which exerts an influence on the turnoff behavior of the petroleum coke.
• the function of the ash fraction is to prevent unwanted combustion of the petroleum coke.
• the petroleum coke mixture is admixed with ash as adjuvant, so that the ash fraction is set at between 2 and 12 weight percent, preferably 2 to 6 weight percent, based on the dry total mixture, and this mixture is ground and classified, giving a fraction having a particle size distribution d of 0.5 ⁇ d ⁇ 3 mm, and the classified mixture for further coking is placed into the coke reservoir bunker or coke storage container. Grinding and classifying are necessary to ensure that the ash is distributed within the product in such a way as not to deleteriously alter the CSR strength and CRI reactivity attained.
• the petroleum coke mixture is admixed with ash-containing coal as adjuvant, so that the ash fraction is set at between 2 and 12 weight percent. preferably 2 to 6 weight percent, based on the dry total mixture, and this mixture is ground and classified, giving a fraction having a particle size distribution d of 0.5 ⁇ d ⁇ 3 min, and the classified mixture for further coking is placed into the coke reservoir bunker or coke storage container.
• the petroleum coke mixture as well before the admixing of the adjuvants or after the admixing of the adjuvants can be wholly or partly ground in a grinding device, to give an average particle size for the residue fraction of less than 3 mm.
• the grinding operation may also be carried out for a partial fraction of the total mixture. Preferred partial fractions in that case are from 70 to 95 weight fraction and more preferably from 80 to 90 weight fraction.
• the water content of the petroleum coke employed by addition of water may improve the stability of the petroleum coke cake.
• the total water content of the charge mixture is adjusted by addition of liquid water to 7 to 11.5 weight percent, and this mixture for further coking is placed into the coke reservoir bunker or coke storage container.
• the water may be added directly, or alternatively by spraying or immersing.
• the charge mixture prior to charging, can be compacted with a densifying device of whatever kind, so that the density of the charge mixture is 0.8 t/m 3 to 1.225 t/m 3 .
• the densifying operation may take place in general by steps of press, ram, hammering or vibrating processes, which may also be performed in combination.
• the charge mixture is compacted with a ram device such that the density of the charge mixture is 1.0 t/m 3 to 1.150 t/m 3 .
• combustion-inert parting layer In order to influence the coking operation, it is possible, before the heating is commenced, to apply a combustion-inert parting layer to the surface a the oven load.
• This layer consists exemplarily of coke.
• this combustion-inert parting layer consists of coal.
• this combustion-inert parting layer may also consist of ash or sand.
• this combustion-inert parting layer may consist of carbon-containing lumps in the form, for example, of lump coal or lump coke having a grain size of less than 25 mm.
• the thickness of the parting layer is 0.2 cm to 25 cm.
• the parting layer can be applied in any way.
• Coke compacting machines which are provided with rams or with hammering, vibrating, and pressing devices for compacting are pan of the prior art and are described by way of example in WO2010102714A2.
• the adjuvant is stored in the coke reservoir bunker in a special shaft from which, during loading of the compacts, the adjuvant is introduced into the opening intended for that purpose in the coke compacting machine.
• the adjuvant may be added into the opening intended for that purpose in the coke compacting machine by means of a screw conveyor.
• the adjuvant may therefore also be added into the opening intended for that purpose in the coke compacting machine by means of a slider system, a chain conveying system, a free-fall means or a slide means.
• the parting layer may also be tipped onto the surface of the hatch subsequently, outside the compacting means.
• the charge mixture is mixed with the adjuvants in four successive mixing bunkers, in which grinding and mixing of the ground material takes place.
• the grinding and mixing may also take place in a plurality of stages.
• the charge mixture may also be preheated.
• the metallurgical coke obtained from the petroleum coke may be put to any further use In particular it may be employed as blast furnace coke. Alternatively, it can he used in nonferrous metallurgy for producing metals or for producing electrodes.
• the external burners can be arranged arbitrarily on the coking oven chamber in order to permit heating of the primary heating space. They may be arranged individually or plurally per coking oven chamber. In one preferred embodiment, however, the burner or burners are located on at least one side of the coking oven chamber, in the wall comprising the coking oven chamber door, over the coking oven chamber door, and heat the primary heating space through an opening located in the wall comprising the coking oven chamber door. Through this opening, the mouthpiece segment of the burner pipe is guided into the gas space.
• the burner or burners are located on at least one side of the coking oven chamber, in the wall comprising the coking oven chamber door, over the coking oven chamber door, and heat the primary heating space through an opening located in the wall comprising the coking oven chamber door, and in one advantageous embodiment a vertical distance of more than 100 mm is established between the burner pipe outlet and the top edge of the petroleum coke batch, Arranging the burners on the ceiling of the coking oven chamber, in turn, is space-saving.
• the burner pipe outlet or burner pipe outlets are made from a heat-resistant steel. In another embodiment, the burner pipe outlet or burner pipe outlets are made from a refractory ceramic material. This may he present on one burner or on a plurality of burners, if a plurality of burners is installed.
• the coking oven of the invention is associated with a further plurality of coking ovens to form a coking oven battery, and the collecting main extends along the coking oven chamber front of the coking oven battery.
• the aggregation of coking ovens of the non-recovery or heat-recovery type into coking oven batteries is something familiar to the person skilled in the art of coking plant technology.
• the secondary heating space as well may be heated with one or more external burners, which are supplied with a heating gas and an oxygen-containing gas via a collecting main along the coking oven chamber front, with regulatable branch lines opening out into t he burners.
• the burner or burners are in the form of blower burners.
• the collecting main may be located by way of example on the coking oven chamber ceiling.
• the collecting main may also be located in mounted form below the platform for the coking oven service machine or along the anchor stands.
• the collecting main may be arranged arbitrarily, in order to ensure the supply to the burner or burners.
• the branch line or branch lines may be regulated, by way of example, via a tap, a slider, a nozzle, a flap, or a shutter.
• the coking oven battery comprises a pressure regulating station in which the heating gas is constricted to the required pressure, and so is passed from the pressure regulating station via the collecting main into the burners, and is provided directly for the burners with the correct pressure.
• a compacting means for compacting coal which is suitable for applying a parting layer to coke compacts during the production of compacts.
• a suitable compacting means which can be utilized for producing this device is described by the teaching of WO2010102714A2.
• Said means consists of six rams, which are used as side faces during the formation of compacts by a pressing device. In one embodiment of the invention, the rams are operated hydraulically.
• a suitable compacting means may also be formed from a vibrating device.
• the upper ram or the upper plate of the vibrating device of the compacting means from WO2010102714A2 is provided with a dumping means by which an adjuvant can be placed onto the surface of the compact, so that, on compacting, a further layer of an adjuvant added by the dumping means is formed on the surface of the compacted charge mixture.
• coking oven battery which is composed of the coking ovens of the invention, and which is equipped with this compacting means.
• the Process of the invention is employed primarily in coking oven batteries which are formed from the coking oven chambers of the invention with ancillary means from the prior art. These include, for example, 1 to 10 type bunkers, in which the different petroleum coke charge mixtures are stored. Also included, for example, are 1 to 4 grinding devices, 1 to 4 screening devices, or 1 to 4 mixing bunkers, in which the petroleum coke, the adjuvants, or the total charge mixture is or are stored, classified, or mixed.
• the coking oven batteries may also have been provided with a compacting means.
• the invention possesses the advantage of providing an economic means of use for a petroleum coke obtained in crude oil refineries and in the mineral oil processing industry, and representing a petcoke fraction having a volatiles content of 15 to 19 weight percent. by producing therefrom a coke which possesses a CSR strength of more than 44% and a CRI reactivity of less than 33%, thereby allowing it, unlike coked petcoke, to be used in a blast furnace operation or in smelting operations for producing metals.
• petcoke serving to provide a petroleum coke which functions as a starting petroleum coke for the process of the invention
• Volatiles content The volatiles content of the petcoke is determined by way of example in accordance with DIN 51720. The quantity measured is the fraction of the residue which remains after heating of the coke under reduced pressure to 900° C. within 7 minutes. A method for rapid determination of the volatiles content of coke is given by U.S. Pat. No. 6,074,205.
• Ash content The ash content is determined by way of example in accordance with DIN 51719. The quantity measured is the fraction of the residue which remains after combustion of the coke in an oven at 815° C. A method for rapid determination of the ash content in coke is given by DE3120064A1.
• Coke strength The strength of coke is determined by the test known as the CSR test.
• CSR here stands for “Coke Strength after Reaction”.
• the quantity measured is the percentage eight of the residue obtained from a 200 g test block of coke after heating under 1 bar of carbon dioxide (CO 2 ) at 1100° C. for 2 hours with subsequent treatment in a rotary drum at 600 revolutions per minute (min ⁇ 1 ) for 30 minutes.
• CO 2 carbon dioxide
• min ⁇ 1 revolutions per minute
• Coke reactivity The reactivity of coke is determined by the test known as the CRI test.
• CRI here stands for “Coke Reactivity Index” and describes the chemical reactivity of the coke.
• the quantity measured is the percentage weight of the residue obtained from a 200 g test block of coke after heating under 1 bar of carbon dioxide (CO 2 ) at 1100° C. for 2 hours. The resulting value is called the CRI reactivity. The smaller the value obtained, the lower the reactivity.
• This method is simple and quick to carry out, and the characteristic CRI value permits good correlation with the behavior of the coke in a blast furnace operation.
• This test method is nowadays generally recognized, has been standardized by ISO 18894, and is described by way of example in EP1142978A1.

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• Engineering & Computer Science (AREA)
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• Oil, Petroleum & Natural Gas (AREA)
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• 2012
  • 2012-03-12 DE DE102012004667A patent/DE102012004667A1/de not_active Withdrawn
• 2013
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  • 2013-03-08 CN CN201380024822.7A patent/CN104334689A/zh active Pending
  • 2013-03-08 US US14/385,148 patent/US20150041304A1/en not_active Abandoned
  • 2013-03-08 WO PCT/EP2013/000694 patent/WO2013143653A1/de active Application Filing
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