WO2013053427A1

WO2013053427A1 - Process for dry cooling of coke with steam with subsequent use of the synthesis gas produced

Info

Publication number: WO2013053427A1
Application number: PCT/EP2012/003969
Authority: WO
Inventors: Holger Thielert
Original assignee: Thyssenkrupp Uhde Gmbh
Priority date: 2011-10-12
Filing date: 2012-09-22
Publication date: 2013-04-18
Also published as: US20140352207A1; RU2014118737A; DE102011115698A1; EP2766453A1; TW201335353A; RU2605125C2; AR088302A1

Abstract

The invention relates to a process for dry cooling of coke with steam with subsequent use of the synthesis gas produced, in which the coal is cyclically converted to coke and the coke, after the coking oven has been unloaded, is introduced into a cooling apparatus, and steam is introduced into the cooling apparatus for dry cooling, such that a water-gas reaction gives rise to synthesis gas composed of carbon monoxide (CO) and hydrogen (H₂), and the synthesis gas produced is sent to a further use. The process allows utilization of the heat which arises in the course of coking for production of valuable synthesis gas, which can in turn be reused or used in heating, such that a very balanced energy budget of the overall process can be achieved overall.

Description

Process for the dry cooling of coke with steam with subsequent use of the synthesis gas produced

The invention relates to a method for the dry cooling of coke with steam with subsequent use of the synthesis gas generated, in which the coal is coked to coke and the coke is discharged after discharge of the coke oven in a cooling device, and in the cooling device for dry cooling steam is introduced, so that by a water gas reaction synthesis gas, which is composed of carbon monoxide (CO) and hydrogen (H ₂ ), is formed, and the synthesis gas produced is fed to a further use. By means of the process, the heat produced during coking can be used to produce valuable synthesis gas, which in turn can be reused or used in heating, so that overall a very balanced energy balance of the entire process can be achieved.

The production of coke is carried out in most of the processes in large coke oven batteries or coke oven benches which are constructed from conventional coke oven chambers or from coke oven chambers of the "heat recovery" or "non-recovery" type. In conventional coke oven chambers, the coking gas is collected and processed while the coking gas is burned in coke oven benches of the "heat recovery" or "non-recovery" type in the coke oven to heat the coke oven. The heating of the coke oven is carried out in many embodiments in several stages in a gas space above the coke cake and in a coke oven sole below the coke oven chamber.

The coking takes place cyclically, the cycles being formed by the processes loading - coking - unloading - deleting. The coke is expressed after coking from the coke oven chamber, where it has a temperature of about 1100 ° C. The expression takes place in a fire truck, which receives the coke cake and transported to an extinguishing device. In many embodiments, this is a wet-quench tower which sprinkles the coke cake with water, which vaporizes and cools the coke cake to a temperature below the ignition temperature of the coke, so that it can be safely transported in the air. The temperature of the coke is distributed unevenly in the coke cake after extinguishing, but is usually less than 100 ° C. An embodiment of a wet quench tower is DE19614482C1. This teaching teaches a plant for wet-quenching hot coke in a process for coking coal with a coke sluice and a coke transfer tube arranged in a quench tower with a water supply device. The cuff fits on the other side on a coke breech, which is equipped at the lower end with a Koksauslassvorrichtung and Wasserauslassklappen. The water supply system is located directly on the transfer collar and discharges into the coke quench truck, which can be watertight shut off, and is equipped with a control system which keeps the coke exhaust flaps closed watertight during the water supply and opens the water outlet flaps upon completion of the water addition. When extinguished with water, all the heat energy stored in the coke cake is lost unused.

For this reason, there are more recent efforts to cool hot coke not by water, but dry by gases. The gases are then passed through the hot coke and collected or sucked off until the coke has cooled to a temperature below its ignition temperature. The hot gas is usually passed through a heat recovery system, where steam is generated and the heat is recovered. The steam in turn can be used to drive auxiliary equipment or to generate electricity. Frequently, inert gases such as nitrogen or blast furnace gas are used for these purposes.

WO9109094B1 describes a process for Kokrockrockkühlung in a cooling chamber by means of recycled cooling gas, with which the speed of the coming out of the coke gas is adjustable so that the grain size of the entrained coke dust particles is less than 3 mm, and the grain size the entrained coke dusts when the hot cooling gas enters the waste heat boiler is less than 1 mm, in which this gas is passed through a device consisting of a cooling chamber and an antechamber having a round, approximately equal cross-section and a cylindrical outer metal sheath, and in particular, the ceiling of the cooling chamber is arranged obliquely so that it rises to the hot gas channel, so as to increase the cross section of the gas ring channel above the Kokschafscheschung so far that the gas velocity of the hot cooling gases during cooling is adjustable so that it almost over the circumference remains the same.

WO8602939A1 describes a method for dry coke cooling by means of cooling gas, wherein the coke and the cooling gas in countercurrent by a two-stage Cooling tank are passed, the cooling in the first stage to coke temperatures of about 800 ° C and the guided through the second cooling stage cooling water contains water vapor, so that a direct coupling of the cooling gas circuit with a thermal treatment step, in which water vapor is added, so that substantially no coke burnup is present, which is achieved in that the cooling in the first cooling stage takes place exclusively by indirect heat exchange of the coke with a cooling medium through heat exchanger walls and the cooling in the second stage exclusively by the water vapor-containing cooling gas.

[0008] The prior art methods for coke dry cooling may be provided with many embodiments. EP0317752A2 describes a method of improving the performance of coke dry cooling plants by breaking hot coke before entering the cooling shaft. DE3030969A1 describes a method for the dry cooling of hot raw coke, which is pressed out of the chambers of a coke oven battery and discharged in a cooling chamber where it is cooled by direct or indirect contact or both with a coolant, so that the raw coke before entering the Cooling chamber is pre-classified in two or more grain classes and the individual grain classes are subjected to the cooling in separate cooling chambers.

Other embodiments are concerned with the heat recovery or cleaning of the cooling gas. DE2435500A1 describes a process for the preheating of coking coal using superheated waste heat which is produced in a dry coker by the coke at its highest temperature level releasing some of its heat to the walls of a steam jacket. DE3217146A1 describes a device for the dedusting of recycle gas Kokstrockenkühlanlage in which the gas inlet channel and the gas outlet channel are arranged at right angles to each other, wherein the gas outlet channel with conical extension directly with the inlet opening of the integrated in the gas cycle waste heat boiler is connected and on the gas inlet passage opposite side is arranged a dust collecting space with an inclined dust discharge surface.

However, the above methods and embodiments thereof have the disadvantage that the heat of the coke is either not recovered when extinguishing, or the heat of the coke can be recovered only with a poor efficiency, since when cooling a large volume of gas is produced must be performed by a heat recovery system, so that cooling is technically difficult or not economical. For that reason, it would be an advantage pressed coke to use existing heat through an endothermic chemical reaction that provides this energy in a chemical form.

A suitable endothermic chemical reaction is the water gas reaction with the associated water gas balance. To carry out this reaction, steam (H ₂ O) is passed through the hot coke, which reacts with the water vapor (H ₂ O) to form hydrogen (H ₂ ) and carbon monoxide (CO). This reaction is endothermic and is:

C + H ₂ O + = H ₂ + CO; ΔΗ = + 131, 3 kJ / mol

A further reaction of the water vapor with the coke to carbon dioxide and two equivalents of hydrogen is possible, but is not carried out according to the invention usually by a suitable dosage and gas velocity of the water vapor. This reaction is strongly endothermic and can only be carried out with additional heating of the coke.

GB347601A describes a process for the preparation of a gas mixture consisting of nitrogen and hydrogen, which is suitable for the synthesis of ammonia, and which is produced in a coke quenching apparatus in which the coke is sprayed with water and traversed by air in which the carbon monoxide is passed to a plant section in which the carbon monoxide is converted to an equivalent of hydrogen by a subsequent conversion of the carbon monoxide with water vapor. The water vapor for the conversion of carbon monoxide comes from the water which is sprayed into the coke cake for cooling the coke. The application does not describe the cooling of the coke cake with gaseous water vapor flowing through.

It is therefore an object to provide a process which uses carbon cyclically to use gaseous water vapor (H ₂ O) for the dry cooling of hot coke after a coking cycle, so that the water vapor (H ₂ O) reacts with the coke at least partially after the water gas equilibrium to hydrogen (H ₂ ) and carbon monoxide (CO), and the obtained hydrogen (H ₂ ) is collected and the gas mixture thus obtained is reused. In this way, synthesis gas is obtained. The deletion of the coke with the water vapor according to the invention is carried out in an extinguishing device, which is preferably kind of an extinguishing shaft. After coking the coal and completing the coking process, the coke cake is driven or dumped onto a fire truck that drives the coke cake into the extinguisher. There, the coke cake is sealed off from the atmospheric environment and gaseous water vapor is passed through the coke cake. This is preferably done in vertically upwardly flowing gas direction, so that the specific heavier water vapor is displaced by the lighter hydrogen in the extinguishing process. The water vapor may be of any kind as a gas mixture and may also be present in a mixture with other gases, but is preferably used in pure form.

In particular, a method for the dry cooling of coke is claimed in the

Coal is heated in a coke oven by heating with a gas containing calorific value, and coke is recovered by cyclic coking, which is expressed in a coke quenching car after completion of the coking, and

• the glowing coke is transported in the coke quenching car to a coke quenching device in which the glowing coke is cooled with a cooling gas to a temperature below the ignition temperature, and which is characterized in that

Is used as the cooling gas gaseous water vapor (H ₂ 0) under exclusion of air, which reacts with the glowing coke (C) according to the water gas reaction at least partially to synthesis gas, which consists of hydrogen (H ₂ ) and carbon monoxide (CO), and · By carrying out the dry quenching in a coke quenching device, the resulting hydrogen-containing quenching gas is collected, and

• the gas mixture thus obtained is reused.

The synthesis gas produced may also contain impurities, but if the reaction is carried out correctly, it consists mainly of the constituents hydrogen (H ₂ ) and carbon monoxide (CO). The water vapor is advantageously generated for carrying out the method in an evaporator vessel. By suitable means for temporary storage of this is kept hot and then introduced with a metering device under pressure in the coke quenching device. In order to prevent condensation of the water vapor during the introduction into the coke quenching device, the feeding pipes can be heated in an advantageous embodiment. In the reaction of the steam with the hot coke then hydrogen (H ₂ ) and carbon monoxide (CO) are formed. The gaseous water vapor used is dry in a preferred embodiment, ie without adherence of water droplets or mist. By the method according to the invention, the heat energy of the coke is used after the coking process during the deletion for the production of recyclables. This can improve the energy balance of the entire coke production process.

The further use of the generated synthesis gas and the hydrogen contained therein can be carried out arbitrarily. In one embodiment of the invention, the further use is an addition to the heating gas of the coke oven (s). In this way, the coke oven is heated with the gas that is produced when extinguishing the coke. For this purpose, the hydrogen, which is used for heating the coke oven, before being added to the coke oven, a hydrocarbon-containing fuel gas can be added. In an exemplary embodiment, the heating gas is natural gas. In a further embodiment, the heating gas is coke oven gas. It is also possible to use blast furnace gas from a blast furnace process as heating gas instead of a hydrocarbon-containing heating gas.

In another embodiment, the synthesis gas is subjected to heat recovery for further use or to feed into the coke oven for heating. This can be achieved for example by passing the gas through a waste heat boiler. In one embodiment of the invention, steam is generated during heat recovery. The steam is then utilized in a typical embodiment to generate mechanical energy by driving a turbine. This in turn can be used to generate electrical energy. It is also possible to pass the synthesis gas generated through a heat exchanger in which the water vapor used for cooling is preheated in countercurrent.

In a further embodiment of the invention, a conversion of the carbon monoxide (CO) by the water gas shift reaction in carbon dioxide (C0 ₂ ) is performed after the deletion of the coke with water vapor (H ₂ 0). This gives you one Gas mixture, which consists mainly of hydrogen (H ₂ ) and carbon dioxide (C0 ₂ ) and which can be easily converted into pure hydrogen, for example by pressure swing adsorption. In one embodiment, the steam required for this purpose can be added in excess to the quenching process or added to the already produced synthesis gas. This can be sprayed after the deletion of the coke as liquid water.

In a further embodiment of the invention, the further use is a conversion of the carbon monoxide with water vapor and subsequent purification of the hydrogen obtained during the conversion in a pressure-swing adsorption plant. The hydrogen may then be used, for example, in a subsequent use in a chemical process. Pressure swing adsorption systems for purifying hydrogen from hydrogen-containing gases are well known in the art. An example of a process for the purification of hydrogen by pressure swing adsorption is taught by WO2006066892A1. In a further embodiment of the invention, the steam for cooling is divided into at least two partial streams. In one embodiment of the invention, a partial stream of water vapor is introduced vertically upward from below into the coke quenching device, and another partial stream of water vapor is introduced into a region of the shaft in which the coke to be cooled has a temperature of 500 to 900 ° C. This can be done, for example, in the shaft laterally mounted feed nozzles that inject the water vapor directly into the coke.

In an exemplary embodiment of the invention, the coke quenching device is a coke quenching shaft. In a further exemplary embodiment of the invention, the coke quenching device is a coking chamber. This can also be equipped, for example, with an antechamber. The extinguishing device or the subsequent transfer line for the hydrogen may also be provided with a dedusting device. As a result, the amount of dust can be reduced if a dusty coal is used, or large quantities of dust are formed during the extinguishing process. The coke oven battery or coke oven bank may be of any kind and be composed as desired to be used for the execution of the method. The coke oven battery from which the coke originates and which is heated with the synthesis gas may be, for example, a coke oven battery in which the coking gas collected and processed. The coke oven bank from which the coke originates may be, for example, a coke oven battery of the "heat recovery" type, since the coke oven bank from which the coke originates may also be a non-recovery coke oven battery "act. The coke ovens, which are arranged in a coke oven battery or bank, can ultimately be arbitrary, as long as they are suitable for the production of coke and optionally for heating with synthesis gas. Also, the removal of the coke and the supply of the synthesis gas obtained in the deletion can be done in different coke oven batteries or banks, but is not usually carried out. The method of the invention may further use at any point auxiliary equipment such as storage tanks for liquids or gases, pumps, valves, heating or cooling devices, mist eliminators, or measuring instruments for temperatures or concentrations of gas components.

The invention has the advantage of utilizing the heat energy of the coke after the coking process by an endothermic chemical reaction, so that the heat energy of the hot coke can be used much better than in the prior art. The invention further has the advantage of providing hydrogen as a valuable material without further addition of energy and thus to enable an improved energy balance of the entire process. As a result, the environmental impact of this process can be significantly improved.

The invention will be further explained by a drawing, this drawing is only an exemplary embodiment and is not limited to this.

FIG.1 shows a coke oven, which serves for the coking of coal. The coke oven chamber (1) with the coal cake (2), the coke oven chamber doors (3), the primary heating chamber (4) above the coke cake (2) and the secondary heating chamber (5) below the coke cake (2) can be seen. Before the coke oven chamber (1) of the fire truck (6) is turned off, which receives the coke cake (2) during the deletion process. This is moved in front of the coke-quenching chamber (7), and the coke cake (2) is emptied into the coke-quenching chamber (7) via a feed flap (7a). This is closed after the filling of the coke quenching chamber (7). From below then flows steam (8, H ₂ 0) in the coke-quenching chamber (7), which reacts with the hot coke cake (5a) after the water gas equilibrium to hydrogen and carbon monoxide (9, H ₂ and CO) as synthesis gas. The water vapor (8) is produced via a steam boiler (10) with a downstream metering device (10a). The synthesis gas (9) produced during extinguishment is drawn off at the top and, after dedusting in a dedusting unit (11), passed as heating gas (9a) into the secondary heating chamber (5) of the coke oven (1). The supply line takes place via a heat exchanger (12) which pre-heats the water vapor (8) introduced to extinguish the coke (2) in countercurrent flow. There it is the partially burned coking gas, which has previously been added from the Primärheizraum (4) in the Sekundärheizraum (5), added and burned. Thereby it contributes to the heating of the coke cake (2) through the bottom of the coke oven chamber (1). After combustion, the completely burned coking gas is discharged from the secondary heating chamber (5) as waste gas (13) and introduced into a device for scrubbing gas (14). The purified exhaust gas (14a) is discharged from the gas scrubber (13) and put into a heat recovery unit (15). There, a generator (15a) is driven via a turbine, which generates electricity. The cooled exhaust gas (15b) is carried out via a chimney (16). The coke (5a) to be extinguished or extinguished is discharged via a discharge flap (7b) and fed to complete extinguishment.

[0030] List of Reference Numerals

1 coke oven chamber

2 coal or coke cake

3 coke oven doors

4 primary boiler room

5 secondary boiler room

5a Coke to be extinguished

6 fire trucks

7 Coke quenching chamber

7a feeder flap

7b unloading hatch

8 water vapor

9 synthesis gas

9a heating gas of Sekundärheizraums

10 steam boilers

10a regulating valve for water vapor

11 storage tanks

12 heat exchangers

13 exhaust

14 Device for gas scrubbing a Purified exhaust gas

Plant for heat recoverya generator

b cooled exhaust gas

fireplace

Claims

claims

1. A process for the dry cooling of coke (5a), in which

Coal (2) is heated in a coke oven (1) by heating with a gas containing heat, and coke (5a) is obtained by cyclic coking, which is expressed after completion of coking in a coke quenching car (6), and

• the incandescent coke (5a) is transported in the coke quenching truck (6) to a coke quenching device (7) in which the glowing coke (5a) is cooled with a cooling gas (8) to a temperature below the ignition temperature, characterized in that

Is used as the cooling gas (8) gaseous water vapor (H ₂ 0) under exclusion of air which with the glowing coke (5a) according to the water gas reaction at least partially to synthesis gas (9), which consists of hydrogen (H ₂ ) and carbon monoxide (CO ), exists, reacts, and

• by the execution of the dry quenching in a coke quenching device (7), the obtained hydrogen-containing quenching gas (9) is collected, and

• the gas mixture (9) thus obtained is reused.

2. A method for dry cooling of coke (5a) according to claim 1, characterized in that it is in the re-use of an addition to the heating gas (9a) of the coke oven or (1).

3. A method for dry cooling of coke (5a) according to claim 2, characterized in that the synthesis gas (9), which is used for heating the coke oven (1), before adding (9a) in the coke oven (1) a hydrocarbon-containing Heating gas is added.

4. A method for the dry cooling of coke (5a) according to claim 3, characterized in that it is the heating gas is natural gas.

5. A method for the dry cooling of coke (5a) according to claim 3, characterized in that it is the coke oven gas in the heating gas.

6. A method for the dry cooling of coke (5a) according to any one of claims 1 to

5, characterized in that the synthesis gas (9) before further use of a heat recovery (12) is subjected.

7. A method for dry cooling of coke (5a) according to claim 6, characterized in that in the heat recovery (12) steam (8) is generated.

8. A process for the dry cooling of coke (5a) according to any one of claims 1 to

7, characterized in that the further use is a conversion of the carbon monoxide (CO) obtained in the gas mixture (9) with water vapor (H ₂ O), in which the carbon monoxide (CO) is converted into carbon dioxide (C0 ₂ ) ,

9. A process for the dry cooling of coke (5a) according to claim 8, characterized in that it is in the further use of a conversion of carbon monoxide (CO) with water vapor (H ₂ 0) and subsequent purification of the resulting hydrogen (H ₂ ) in a pressure swing adsorption plant is.

10. A process for the dry cooling of coke (5a) according to any one of claims 1 to

9, characterized in that the water vapor (8) is divided into at least two partial streams for cooling, and a partial stream of water vapor (8) is introduced vertically upward from below into the coke quenching device (7), and a further partial stream of the water vapor (8). is introduced into a region of the coke-extinguishing device (7), in which the coke (5a) to be cooled has a temperature of 500 to 900 ° C.

11. A method for the dry cooling of coke (5a) according to any one of claims 1 to

10, characterized in that it is the Kokslöschvorrichtung (7) is a coke quencher.

12. A method for dry cooling of coke (5a) according to any one of claims 1 to

10, characterized in that the coke-extinguishing device (7) is a coke-quenching chamber.

13. A method for the dry cooling of coke (5a) according to claim 12, characterized in that the coke-quenching chamber (7) is equipped with an antechamber.