Process and apparatus for producing metallurgical coke from petroleum coke obtained in mineral oil refineries by coking in "non-recovery" or "heat-recovery" coking ovens

Abstract

The invention relates to a process for producing metallurgical coke from petroleum coke generated in crude oil refineries, by coking in “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 “hat-recovery” construction for the purpose of cyclical coking, said oven being equipped with at least one externally heated burner, so that the primary healing space or the secondary heating space below the coking oven chamber, or both, are heated to a temperature of between 1000° C. to 1550° C., and within a time period of less than 120 h, the volatiles fraction present in the petroleum coke is completely outgassed, giving a metallurgical coke having a CSR strength of at least 44% and a CRI reactivity of less than 33%, being suitable for use as iron- and steelmaking coke 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, and which is equipped with burners which heat the primary heating space.

1 . A process for producing metallurgical coke from petroleum coke obtained in the crude oil processing industry, where
 petcoke from petrochemical processes is subjected to analysis of the volatiles content and the ash content, so that it can be sorted into hatches with a known content of volatile constituents and ash content, and   a petroleum coke batch with 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, is obtained by sorting, and is placed into a coke reservoir bunker or coke storage container, and   this petroleum coke fraction from the coke reservoir bunker or coke storage container is placed by filling machines first into a compacting means for densification and then into a coking oven with the dimensions of the “non-recovery” or “heat-recovery” design for cyclical coking,   
       characterized in that
 the coking oven is equipped with at least one externally heated burner for heating the primary heating space above the petroleum coke cake or tot heating the secondary heating space below the coking oven chamber, or both, by which the petroleum coke in the coking oven chamber is heated with a heating gas to a temperature of 1000° C. to 1550° C. within a time period of less than 120 h, to give a metallurgical coke having a CSR strength of at least 44% and a CRI reactivity of less than 33%. 
 
     
     
         2 . The process as claimed in  claim 1 , characterized in that the volatiles content of the petroleum coke prior to coking is 16 to 18 weight percent. 
     
     
         3 . The process as claimed in either of  claims 1  and  2 , characterized in that the heating is performed in the coking oven, by the burner flame being introduced into the gas space over the petroleum coke batch. 
     
     
         4 . The process as claimed in any of  claims 1  to  3 , characterized in that the coking oven is equipped with at least one externally heated burner for heating the secondary heating space below the petroleum coke cake, by which the petroleum coke cake is heated. 
     
     
         5 . The process as claimed in  claim 4 , characterized in that the heating is performed in the coking oven by the burner flame being introduced into the gas space below the petroleum coke batch. 
     
     
         6 . The process as claimed in any of  claims 1  to  5 , characterized in that the heating is adjusted with the aeration and pressure regulation in such a way that an overpressure of 0.01 to 20 mbar is established in the coking oven chamber. 
     
     
         7 . The process as claimed in any of  claims 1  to  5 , characterized in that 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. 
     
     
         8 . The process as claimed in any of  claims 1  to  7 , characterized in that natural gas is used as heating gas for the heating. 
     
     
         9 . The process as claimed in any of  claims 1  to  7 , characterized in that liquid gas is used as heating gas for the heating. 
     
     
         10 . The process as claimed in any of  claims 1  to  7 , characterized in that coking oven gas is used as heating gas for the heating. 
     
     
         11 . The process as claimed in any of  claims 1  to  7 , characterized in that blast furnace top gas is used as heating gas for the heating, 
     
     
         12 . The process as claimed in any of  claims 1  to  7 , characterized in that converter gas is used as heating gas for the heating. 
     
     
         13 . The process as claimed in any of  claims 8  to  12 , characterized in that a mixture of at least two gases from the gases group—natural gas, liquid gas, coking oven gas, blast furnace top gas, or converter gas—in any proportion is used for the heating. 
     
     
         14 . The process as claimed in any of  claims 1  to  13 , characterized in that prior to grinding, the petroleum coke mixture 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. 
     
     
         15 . The process as claimed in any of  claims 1  to  13 , characterized in that prior to grinding, the petroleum coke mixture is mixed with bitumen as adjuvant, so that the volatiles content is between 19 and 25 weight percent, based on the dry charge mixture. 
     
     
         16 . The process as claimed in any of  claims 1  to  13 , characterized in that prior to grinding, the petroleum coke mixture 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. 
     
     
         17 . The process as claimed in any of  claims 1  to  16 , characterized in that the petroleum coke mixture is admixed with ash as adjuvant, so that the ash fraction is set at between 2 and 12 weight percent, based on the dry total mixture, and this mixture, prior to coking, is ground and classified, giving a fraction haying 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. 
     
     
         18 . The process as claimed in any of claims I to  16 . characterized in that 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, based on the dry total mixture, and this mixture, prior to coking, is ground and classified, giving a fraction baying 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. 
     
     
         19 . The process as claimed in  claim 18 , characterized in that the petroleum coke mixture is admixed with ash-containing coal as adjuvant, so that the ash fraction is set at between 2 and 6 weight percent, based on the dry total mixture, and this mixture, prior to coking, 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. 
     
     
         20 . The process as claimed in any of  claims 14  to  19 , characterized in that the petroleum coke mixture as well, before or after the admixing of the adjuvants, is wholly or partly ground in a grinding device, to give an average particle size of the residue fraction of less than 3 mm. 
     
     
         21 . The process as claimed in any of  claims 1  to  20 , characterized in that 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 thither coking is placed into the coke reservoir hunker or coke storage container. 
     
     
         22 . The process as claimed in any of  claims 1  to  21 , characterized in that the charge mixture, prior to charging, is compacted with a densifying device, so that the density of the charge mixture is 0.8 t/m 3  to 1.225 t/m 3 . 
     
     
         23 . The process as claimed in any of  claims 1  to  21 , characterized in that the charge mixture, prior to charging, is compacted with a ram device, so that the density of the charge mixture is 1.0 t/m 3  to 1.150 t/m 3 . 
     
     
         24 . The process as claimed in any of  claims 1  to  23 , characterized in that before the heating is commenced, a combustion-inert parting layer is applied to the surface of the oven load. 
     
     
         25 . The process as claimed in  claim 24 , characterized in that this combustion-inert parting layer consists of coke. 
     
     
         26 . The process as claimed in  claim 24 , characterized in that this combustion-inert parting layer consists of coal. 
     
     
         27 . The process as claimed in  claim 24 , characterized in that this combustion-inert parting layer consists of carbon-containing lumps having a grain size of less than 25 mm. 
     
     
         28 . The process as claimed in  claim 24 , characterized in that this combustion-inert parting layer consists of ash or sand. 
     
     
         29 . The process as claimed in any of  claims 24  to  28 , characterized h that the thickness of the parting layer is 0.2 cm to 25 cm. 
     
     
         30 . The process as claimed in any of  claims 24  to  29 , characterized in that the parting layer is applied to the compacted coke with a coke compacting machine which includes an addition opening intended for that purpose on the upper die or upper plate. 
     
     
         31 . The process as claimed in any of  claims 24  to  30 , characterized in that the adjuvant is stored in the coke reservoir bunker in a special shaft from which, during loading, the adjuvant is placed into the opening intended for that purpose in the coke compacting machine. 
     
     
         32 . The process as claimed in  claim 31 , characterized in that the adjuvant is added into the opening intended for that purpose in the coke compacting machine by means of a screw conveyor. 
     
     
         33 . The process as claimed in  claim 31 , characterized in that the adjuvant is added into the opening intended for that purpose in the coke compacting machine by means of a slider system. 
     
     
         34 . The process as claimed in  claim 31 , characterized in that the adjuvant is added into the opening intended for that purpose in the coke compacting machine by means of a chain conveying system. 
     
     
         35 . The process as claimed in any of  claims 24  to  34 , characterized in that the charge mixture is mixed with the adjuvants in up to four successive mixing hunkers, in which multistage grinding and mixing of the ground material takes place. 
     
     
         36 . The process as claimed in any of  claims 1  to  35 , characterized in that the temperature of the charge mixture, before it is filled into the coking oven, is preheated to 120° C. to 250° C. in a heatable container. 
     
     
         37 . A coking oven for coke generation from petroleum coke obtained in the crude oil processing industry, which oven
 is constructed on the principle of a “heat-recovery” coking oven battery, which possesses a coking oven chamber width of 2 to 6 meters and a coking oven chamber length of 10 to 20 m, so that, for a height of 2 m, the volume of the coking oven chamber is 40 to 240 m 3 , and   the coking oven possesses a brick-lined roof apex, which is able, with the underlying coking oven chamber, to form a gas space which is present over the coke cake in the filled state, as primary heating space, and   the coking oven is equipped with lateral off-gas channels and an underlying secondary heating space, and   the coking oven chamber is furnished with a coke reservoir bunker or coke storage container and a filling machine which is able to fill the coking oven chamber from the coke reservoir hunker or coke storage container,   
       characterized in that
 the coking oven chamber is heated with external burners which heat the primary heating space, and the burners are supplied with a heating gas and an oxygen containing gas via collecting mains along the coking oven chamber front and regulatable branch lines into the burners. 
 
     
     
         38 . The coking oven as claimed in  claim 37 , characterized in that 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, with a vertical distance of more than 100 mm being established between the burner pipe outlet and the top edge of the batch. 
     
     
         39 . The coking oven as claimed in either of  claims 37  and  38 , characterized in that the burner pipe outlet is made from a heat-resistant steel. 
     
     
         40 . The coking oven as claimed in either of  claims 37  and  38 , characterized in that the burner pipe outlet is made from a refractory ceramic material. 
     
     
         41 . The coking oven as claimed in any of  claims 37  to  40 , characterized in that the coking oven 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. 
     
     
         42 . The coking oven as claimed in any of  claims 37  to  41 , characterized in that the secondary beating space as well is heated with an external burner, which is supplied with a heating gas and an oxygen-containing gas via a collecting main along the coking oven chamber front, said main opening out into the burner via a regulatable branch line. 
     
     
         43 . The coking oven as claimed in any of  claims 37  to  42 , characterized in that the burner or burners are in the form of blower burners. 
     
     
         44 . The coking oven as claimed in any of  claims 37  to  43 , characterized in that the collecting main is located on the coking oven chamber ceiling. 
     
     
         45 . The coking oven as claimed in any of  claims 37  to  44 , characterized in that the collecting main is located below the platform for the coking oven service machine. 
     
     
         46 . The coking oven as claimed in any of  claims 37  to  45 , characterized in that the branch line or branch lines is or are regulated is as tap, a slider, a flap, as nozzle or a shutter. 
     
     
         47 . The coking oven as claimed in any of  claims 37  to  45 , characterized in that the coking oven battery comprises a pressure regulating station in which the heating gas is restricted to the required pressure, and is passed thus from the pressure regulating station via the collecting main into the burners. 
     
     
         48 . A compacting means for compacting coal, which consists of up to eight rams, the rams being used to form compacts by means of a densifying device, characterized in that the compacting means comprises a dumping means by which an adjuvant can he 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. 
     
     
         49 . The compacting means for compacting coal as claimed in  claim 48 , characterized in that the compacting means comprises a hydraulic pressing device fur the formation of compacts. 
     
     
         50 . The compacting means for compacting, coal as claimed in  claim 48 , characterized in that the compacting means, which is used to form compacts, is formed by a vibrating device. 
     
     
         51 . A coking oven battery as claimed in any of  claims 37  to  50 , characterized in that it is equipped with a compacting means as claimed in any of  claims 48  to  50 .