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
  • C10B39/00—Cooling or quenching coke
  • C10B39/02—Dry cooling 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
  • C10B57/08—Non-mechanical pretreatment of the charge, e.g. desulfurization
  • C10B57/10—Drying
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F26—DRYING
  • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
  • F26B23/00—Heating arrangements
  • F26B23/001—Heating arrangements using waste heat
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P20/00—Technologies relating to chemical industry
  • Y02P20/10—Process efficiency
  • Y02P20/129—Energy recovery, e.g. by cogeneration, H2recovery or pressure recovery turbines
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
  • Y02P70/10—Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working

Definitions

• the invention is directed to a process for the predrying and preheating of coal for use in coke ovens, which serve to produce metallurgical coke, wherein an inert gas is used to heat the coal, which is used in the dry cooling or deletion of hot Coke with another primary gas was heated by indirect heat exchange, wherein as an inert gas hot steam, which is suitable for pre-drying and preheating of coal, is used, and as a drying or heating step, an air flow heating, a fluidized bed heating, or a heating of the Coal is selected in a rotary drum.
• the invention takes account of the procedural coupling with combustion air preheating for the coke ovens.
• the invention is further directed to an apparatus for preheating and drying coal which consists of a coke cooling chamber for hot coke, a primary cooling circuit for an inert cooling gas, a heat exchanger, a secondary cooling circuit for a secondary cooling gas, and a rotary drum Rotary drum can also be replaced by a fluidized bed reactor, or a entrained flow reactor with coal grinding device.
• Some coal coking processes therefore, heat the coal outside the coke oven before it is loaded into the coke oven chamber. This requires a lot of energy.
• One possibility is to preheat the coal by the raw gas that is produced during the coking and which is used for pre-drying and preheating the coal before it is discharged for further processing.
• the raw gas has a high temperature immediately after coking and can therefore be used for preheating the coal.
• An example of this is DE4204578C2.
• This embodiment is particularly suitable for coke ovens of the type "non-recovery” or “heat recovery”, in which the coking gas is completely burned, and thus is available after combustion as exhaust gas for heating coal.
• These furnaces typically include a primary and a secondary boiler room for the stepwise combustion of the coking gas.
• the exhaust gas is no longer or only to a limited extent available for heat recovery by a steam and power generation unit after the coal has been pre-heated.
• This document describes a method for energy recovery in gas generation processes, which also coal coking plants are called, for the purpose of drying or preheating the feedstock, especially the fine coal for coking operation by the drying and preheating of the feedstock by means of the waste heat, the cooling of the solid residue of the process, for example, in the dry deletion of the coke in a coking plant in a closed, equipped with a Staubabschei- tion primary gas cycle is recovered, and in which as heat transport and drying an inert gas such as nitrogen, carbon dioxide, flue gas from coke ovens or flue gas is used from the top gas combustion in a secondary gas cycle with dust separation.
• This uses the sensible heat of the expressed coke to preheat coal.
• Preheat combustion air may be used for a "heat recovery" coke oven or for heating another gas in a secondary gas loop
• the primary gas is recirculated and cleaned of the solids that form when the coke is extinguished in the primary gas loop
• heat is transferred to a secondary inert gas in a heat exchanger, and the secondary gas can then be used for pre-drying and preheating coal which is heated by a heat exchanger by indirect heat exchange with the primary gas.
• the deletion of the hot coke with an inert gas and the preheating of the coal raises the problem that the heat exchange must be efficient in order to achieve an acceptable coal heating rate.
• the gas flow rate in the primary gas cycle is high due to the large volume of gas in relation to the coke volume, and the rate of heating of the coal due to the slow heating rate of the coal in the second gas circuit low, while simultaneously due to the high gas velocity in the first gas cycle only a moderate heat transfer rate in the heat exchanger is possible. This is constantly looking for ways to improve the heat transfer in the dry quenching of coke on the coal to be used.
• the present invention with the present main process claim solves this object by a method for improved predrying of coal by heat exchange with the cooling gas of a Kokstrockenkühlstrom, wherein a hot, incandescent Kokscharge is placed in a coke quenching device, which is connected to a primary cooling circuit in which the coke is flowed through with an inert gas, and is thereby cooled down to a lower temperature, and the inert cooling gas in a heat exchanger releases the sensible heat by indirect heat exchange with water vapor in a second, secondary gas circuit, so that in this secondary gas cycle Coal, which is intended for coking, is pre-dried and heated with the steam as a secondary inert gas, and the thus preheated and dried coal can be placed in a coking-chamber provided for a coking cycle, and there in a coking cycle is coked under the introduction of air to coke.
• the coal is heated directly with steam to temperatures above 100 ° C.
• the method may be modified such that the heat exchanger is used to evaporate water, and in this way to produce water vapor when no suitable source of steam is available.
• the water vapor thus generated can be heated sufficiently high by the method, so that a sufficient pre-drying and heating of the feed coal is still possible. In this case, further heating can also be carried out, if necessary, by means of a steam superheater, so that sufficient preheating of the feed coal is readily possible.
• the steam must be sufficiently high in temperature to practice the present invention so that the coal does not have to be coked in a wet state.
• a coke oven suitable for cyclical coking of coal is discharged after a coking cycle has been carried out to obtain a hot, glowing coke charge
• Coke is flowed through with an inert gas, and thereby cooled down to a lower temperature, and the inert cooling gas flows through a heat exchanger in which it emits the sensible heat by indirect heat exchange to another secondary, inert gas in a second, secondary gas cycle, and in this secondary gas cycle coal, which is intended for coking, with the secondary inert gas is pre-dried and heated, and the thus preheated and dried coal is placed in a provided for a coking cycle coke oven chamber, where it is coked in a coking cycle to coke, and
• a temperature of more than 100.degree. C. is to be regarded as a suitable temperature, since at this temperature the steam does not condense on the coal, and this temperature already produces a significant energy saving during coking.
• this temperature is a lower limit, since higher temperatures provide a much higher energy savings, and heating to a temperature below 100 ° C due to condensation phenomena of water vapor is not suitable for coking coal.
• the temperature of the coal is determined by temperature sensors in the drying unit. For carrying out the following invention, a temperature of the preheated and dried coal of 120 ° C to 250 ° C has been found to be very suitable.
• the invention therefore transfers the heat in the secondary gas cycle to the combustion air, which is thereby preheated to temperatures greater than 100 ° C. and then conducted in the preheated state to combustion of the raw gases at any point in the coke oven. operating in countercurrent, crosscurrent or direct current mode, or a combination of several subprocesses.
• the primary gas cycle is closed to practice the invention, which means that it keeps the coke closed during the extinguishing process.
• the primary gas for extinguishing can be taken for example from a storage container, and used as desired. This can also be done in a circle.
• the primary inert gas for dry extinguishing the coke may be nitrogen, carbon dioxide, blast furnace gas, coke oven gas, or a noble gas. These gases are only examples.
• the inert gas may also be steam, provided that it is not used at temperatures above 800 ° C.
• the gases mentioned can also be used in a mixture.
• the primary gas cycle can contain blowers or compressors at any point. Recuperation in the primary gas cycle is also possible.
• the coal is preheated in a rotary drum with the steam. This is particularly advantageous when a relatively coarse coal is used, which must be heated to a temperature suitable for coking within a short time.
• the coal is preground for preheating, and preheated in an air stream heater with the steam.
• an air stream heater with the steam.
• the grain size of the coal for air flow heating can ultimately be arbitrary, as long as it is suitable for Flugstromerhitzung.
• a suitable process for the air flow heating of coal is the DE3730053A1.
• the coal is preheated in a fluid bed dryer with the steam.
• the fluidized bed dryer typically consists of a grate which is provided with passage openings for the hot steam.
• the passage openings of the grate in the fluid bed dryer then have an opening cross-sectional area which is smaller than the smallest grain size of the coal to be pre-heated. If a larger cross-sectional area of the steam vents is selected than the smallest grain size of the grain fractions of the pre-dried coal used, it is to be expected in the order of magnitude of the coal falling through the fluidized bed.
• a method for fluidized bed heating of coal is the DE102004043687A1.
• the steam must for carrying out the invention have a sufficiently high temperature in order to avoid condensation phenomena in the secondary gas cycle.
• the steam for heating the coal has a temperature of 120 ° C to 900 ° C. Lower temperatures are usually unsuitable depending on the device used, since these lead to condensation phenomena. However, higher temperatures are possible at any time as long as the materials used are sufficiently resistant.
• the steam for heating the coal can be used at atmospheric pressure or at elevated pressure, as is typically obtained in the generation of water vapor. Higher pressures are usually undesirable because they do not produce the desired drying effect of the coal. An application of higher pressures is possible in principle within the scope of the invention. However, it is also possible to carry out predrying and preheating of the coal at a reduced pressure. In this case, a slightly higher investment costs for pressure reduction, for example by vacuum pumps is required. In one embodiment of the invention, the drying steam has a reduced pressure of 0.5 bar to 0.9 bar relative to 1, 013 bar atmospheric pressure. This is particularly advantageous when using moist coal feed, as can be achieved by the application of negative pressure faster drying.
• the water vapor used to heat the coal is at least partially recovered in a kettle by heating via indirect heat exchange with the primary gas loop.
• This embodiment is particularly suitable when no system part is available for generating steam. If the steam is recovered by heat exchange with the primary gas cycle, it must have a sufficient temperature for coal heating. This also depends on the capacity of the heat exchanger and thus on the dimensioning of the primary gas cycle. If the temperature of the water vapor required for coal pre-drying is not reached, then a reheater for the steam in front of the coal preheating tank must be interposed. This can be heated and operated as desired.
• the preheated coal according to the invention can be added directly from the coal preheating tank in the proposed coke oven chamber.
• a storage of the preheated coal makes sense, so that at any time a heated coal storage container can be used to carry out the invention.
• the preheated coal can be used directly, but is preferably stored in a hot coal bunker before use. This hot-coal bunker is thermally insulated and heated.
• the heated coal can be withdrawn continuously or discontinuously for coking.
• the further use is carried out by transport lines, as described by way of example in WO201 1107198A1.
• Pre-treatment steps may also be carried out prior to the use of the preheated coal, such as, for example, grinding up the coal, or mixing the coal with other cokemable components, such as anthracite coal, petroleum coke or rubber shreds.
• the coke-quenching apparatus which is a coke-quenching vessel or coke-quenching shaft and used as a coke-cooling device, is continuously filled in one embodiment of the invention. However, it is also possible to fill these batchwise in batch charging operation.
• the primary and secondary gas circuits may contain de-pollution facilities at each location. These are in a preferred embodiment Staubabscheiderzyklone or filter.
• the primary gas is preferably used exclusively for heating the secondary gas, ie the water vapor, but can deliver its heat to any other processes.
• the heat exchange between primary and secondary gas can take place in counterflow, in cross guide or in parallel guidance.
• the heating of the coal can be carried out in one or more stages, for example first for drying and then for pre-heating for coking. It can be used in all stages a rotary drum, a flow stream drying, or a fluidized bed drying, or in combination.
• coal which serve as coal for coking and preheating or predrying
• all types of carbon come into consideration, which are suitable for coking.
• the inventive method can be used to exemplify blast furnace coke for the reduction of iron ore, foundry coke or electrode coke.
• the inventive method can also be used in all available coke ovens.
• These may be coke ovens of the "non-recovery” or “heat-recovery” type, in which the coking gas is used for heating by staged combustion.
• these can also be conventional coke ovens, which collect the coking gas for further processing.
• the coke ovens suitable for the process according to the invention are preferably provided with a device for preheating equipped with air. These can be "regenerators” with a gas exchange or “recuperators” without direct gas exchange. It is also possible according to the invention to carry out a transfer of residual heat to the combustion air following the heat transfer to the preheated coal.
• a heat exchanger downstream of any desired type in the flow direction can be used.
• the inventive method is used to produce blast furnace coke for the production of pig iron. This requires average coking temperatures of more than 1200 ° C and coking times of 72 hours (h) or less.
• the designated cooling chamber is filled with hot coke at least once per hour, depending on the number of coke oven chambers. The coke is obtained after coking at a temperature of 950 to 1150 ° C and cooled to a temperature of 200 ° C.
• the cooling chamber is usually in excess of the ambient pressure.
• the inventive method is used to produce foundry or Elektrodenkoks. This requires average coking temperatures of less than 1200 ° C and coking times of 72 hours or more.
• the designated cooling chamber is also filled depending on the number of coke oven chambers at least once per hour with hot coke.
• this process variant is characterized by a Koksendtemperatur of less than 950 ° C and the coke is cooled by the dry cooling to a temperature of 200 ° C.
• a usable process heat of about 150 GJ / h to 160 GJ / h (about 43 MW) is obtained.
• the cooling chamber is usually in overpressure compared to the environment.
• the heat obtained in this case can be used in various ways.
• a portion of the total heat from 150 GJ / h to 160 GJ / h (43 MW) is used to preheat the coal from ambient to a temperature of 240 ° C to 260 ° C. This corresponds to a quantity of heat in Height from 80 GJ / h to 90 GJ / h (about 25 MW).
• the remaining heat of 18 MW is used to raise the combustion air in a "Heat Recovery" coke oven to a temperature level of 140 ° C to 160 ° C.
• This process variant reduces the time required for the complete coking of the coal charge from a baseline of 100% to about 30% to 40% of the coking time, which is equivalent to reducing the net cooking time to a total of less than 30 hours for "heat recovery" coke ovens.
• a portion of the total heat of 150 GJ / h to 160 GJ / h is used to preheat the coal from ambient temperature to a temperature range of 100 ° C to 130 ° C.
• the combustion air is preheated to temperatures of about 230 ° C to 240 ° C.
• This process variant reduces the net time required for the complete pyrolysis of the coal charge from a baseline of 100% to about 55% to 65% of the coking time. For coke ovens of the "Heat Recovery" type, this corresponds to a reduction of the net cooking time to a total duration of less than 40 hours.
• a part of the total heat of 150 GJ / h to 160 GJ / h is used exclusively for preheating the combustion air, wherein an air preheating temperature of 310 ° C to 330 ° C sets.
• This process variant reduces the net fermentation time required for complete pyrolysis of the coal charge from a baseline of 100% to about 85% to 95% of the coking time. In the case of coke ovens of the "heat recovery" type, this corresponds to a reduction of the net cooking time to a total duration of less than 50 h.
• a coke oven bank or coke oven battery consisting of a juxtaposition of coke ovens for the cyclical coking of coal and equipped with the requisite accompanying equipment to carry out the cyclical coking
• a Kokskühl which is capable of receiving the Kokscharge from at least one coking cycle, and which is equipped with a discharge device for removing the inert coke extinguishing gas, which opens into a closed primary gas circuit, wherein the gas cycle at least one point has a heat exchanger which an indirect heat exchange to a secondary gas cycle
• a secondary gas loop which is heated by the heat exchanger via indirect heat exchange with the primary gas loop and which is equipped with a coal container for heating the coking coal intended for coking, wherein the carbon container is not installed in or on the heat exchanger for heating the secondary gas cycle .
• a coal container for heating the charge coal intended for coking which is equipped with at least one gas inlet nozzle and a gas outlet nozzle for the flow through with the gas from the secondary gas circuit,
• coal container is a carbon storage device, which is equipped with inlet openings for the passage of the hot secondary gas, and is equipped with at least one inlet port and a discharge port for the hot gas, wherein
• the device must be resistant and resistant to the hot steam at any point where it comes into contact with hot water vapor.
• base material for example, stainless steel comes into question.
• the coal container or the carbon storage device is a container which is equipped inside with a rotary drum having inlet openings for the passage of the hot water vapor as a secondary gas.
• the inlet openings as steam inlet openings of the rotary drum advantageously have an opening cross-sectional area which is smaller than that smallest particle size of the usually used preheated coal. If a larger cross-sectional area of the steam inlet openings is chosen than the grain size of the coal to be pre-dried, a loss of coal is to be expected in the order of magnitude of the coal falling through the fluidized bed.
• the coal container or the carbon storage device is a container with a fluidized bed, which is equipped with inlet openings for the flow through the fluidized bed with the hot water vapor as a secondary gas.
• the fluidized bed consists of a grate for storing the coal, through which steam flows from one side.
• the inlet openings of the grate in the fluidized bed dryer advantageously have an opening cross-sectional area, which is smaller than the smallest grain size of the usually used to be reheated coal.
• the carbon container or the carbon storage device is an air flow dryer.
• An entrainment dryer in a typical embodiment, is such that the pre-ground coal with the hot gas, which is hot steam in the present invention, is pneumatically conveyed through a sufficiently sized pipeline endowed with a dried coal containment device , wherein the drying is carried out during the pneumatic conveying. This makes sense especially for finely divided coal.
• the heat exchanger between the primary and the secondary gas circuit for generating hot steam contains a steam boiler for generating steam.
• This embodiment is chosen in particular when no generating unit for water vapor is available at the coke oven plant.
• the steam boiler can also be equipped with a downstream in the steam flow direction reheater.
• At least one dust separator can be installed in the secondary gas line for water vapor behind the carbon container.
• the carbon particles which are entrained in the preheating of the coal by the steam, remove from the water vapor.
• at least one fan is located in the primary or secondary gas line, which is for a particular seren gas flow in the gas lines provides. This can be single or multiple in one or both lines.
• the secondary gas cycle may be a heat exchanger, which preheats air for combustion of the coking gas in the coke oven chamber, and which is equipped with at least one conduit for the supply of preheated air in the coke oven chambers.
• the combustion air for the coke oven chambers can be preheated.
• the heat exchanger for preheating the combustion air is a heat exchanger of the "regenerator” or "recuperator” type. This heat exchanger can be operated in countercurrent, DC or crossflow mode. An installation of the heat exchanger in the primary gas cycle is conceivable, although this is not the preferred embodiment.
• the heat exchanger for preheating the air is a "recuperator.” This heats the combustion air for the coke oven chambers by indirect heat exchange In one embodiment of the invention, the heat exchanger for preheating the air is a "regenerator”. This can be equipped with ceramic regenerators as an example. The "regenerator” allows heating of the combustion air for the coke oven chambers by mixing the gases.
• the pipeline for the supply of preheated air into the coke oven chambers can branch into a primary and secondary air line in the region of the coke oven chamber, so that the primary heating chambers and the secondary heating chambers can be supplied with preheated air.
• the pipeline for the supply of preheated air in the coke oven chambers may further include a fan through which the preheated air is passed to the coke ovens.
• the process according to the invention can at any point in the process flow contain process steps which are necessary or helpful for extinguishing coke or for preheating coal for coking. This is, for example, an additional quenching of coke after the dry-erase operation, in which the coke is cooled to its final processing temperature.
• the device according to the invention can furthermore have at any place auxiliary devices such as storage containers for solids, for liquids or steam, pumps, valves, heating or cooling devices, mist eliminators, or measuring instruments for temperatures or concentrations of gas components included.
• the device according to the invention can also have dedusting units at any point in the process flow.
• the inventive method has the advantage, by the high heat capacity of steam an efficient method for drying and preheating coal, which is provided for the coking of coal, to provide.
• the apparatus according to the invention has the advantage of providing a means to heat coal quickly and efficiently with hot steam, achieving a sufficiently high rate of heat exchange between the coal and the hot water vapor, and the sensible heat obtained by dry quenching of the coke is used to preheat coal. As a result, an improved economy of the entire process is achieved.
• FIG. 1 shows a device according to the invention with a coke oven (1) with a coke oven chamber (2) in which coal (3) is cyclically coked into coke (4).
• the coke (4) is discharged via a coke quenching truck (5) and placed in a coke quenching device (6), which is here designed as coke quenching shaft.
• the coke quencher can be loaded and unloaded via flaps intended for loading (6a) and unloading (6b).
• the coke quenching shaft (6) is passed through with an inert gas (7), which here is nitrogen (7, N 2 ) from a feed tank (8).
• the coke (4a) By flowing through with the cool nitrogen (7), the coke (4a) is cooled down to a lower temperature, so that the coke (4a) can be processed further, or can be cooled and extinguished at a lower cost to the further processing temperature.
• this heats up by the hot coke (4a) whereupon it flows through a heat exchanger (9) by a dedusting unit (7a) after dedusting.
• the water vapor (10) is generated in a water vapor generation unit (11) and passed through the heat exchanger (9) at about 150 ° C. This heats up to about 400 ° C.
• the hot water vapor (10) flows through a rotary drum (12) which is charged with coal (3a).
• the coal (3a) heats up to a temperature of over 200 ° C.
• the temperature of the preheated coal (3a) depends on the flow time of the steam (10), which is selected for preheating a coal charge (3a).
• the water vapor (10) in a dedusting unit (10a) dedusted. Both the nitrogen (7) and the water vapor (10) are given after the extinguishing of the coke (4) or the preheating of the coal (3a) in a system part (13) for recovering the heat.
• current is obtained via an ordinary turbine generator process (13a).
• the cooled and dedusted exhaust gas (13b) is carried out.
• the preheated coal (3b) is placed in a hot coal bunker (14) for preheated coal (3b).

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• 2012
  • 2012-06-25 DE DE102012012417.1A patent/DE102012012417B4/de active Active
• 2013
  • 2013-06-12 WO PCT/EP2013/001733 patent/WO2014000861A1/de active Application Filing
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