KR810001673B1 - Process for drying and preparating coking coal by means of flue gas - Google Patents

Abstract

Process for producing heat in a coking plant is described in which the coke cooling and preheating is effected using the burned gases of the coke oven battery as heat-transfer gas, optionally often separation of O2. The coke cooling plant and the coke heating plant are in direct contact with the coke input equipment. The burned gases leaving the coke oven battery before passing to the coke coling plant is passed through a cooling step for direct or indirect cooling and for condensation of the water vapor.

Description

Drying and preheating method of coal for producing coke using flue gas

An illustration of the device according to the invention.

The present invention by directly contacting the flue gas discharged from the oven for producing coke with the hot coke discharged from the oven and the raw coal for coke production to cool the hot coke emitted by the sensible heat from the coke manufacturing apparatus and coke A method for preheating coal for production.

According to British Patent No. 1,334,372, a system is known for using hot coke sensible heat generated during coke production for drying and preheating coal. In this method, the inert gas is passed through hot coke and coal to cool the coarse and preheat the coal. In this case, a part of the combustion product generated by the combustion of the fuel is used as the inert gas in the coke production. This method requires pretreatment to remove oxygen from the heat carrier gas supplied to the coke cooler, as well as the heat carrier gas to pass through the coal preheater. In addition, the above-mentioned British patent method has a problem that a dust separator and a compressor must be provided.

German Patent Publication No. 24 15 758 discloses a device for continuously drying and preheating coal by using heat transferred from hot coke to a mixed gas with a coke dry quenching device. The apparatus includes a quench gas circulation path and a dry gas passage, and the system includes a post-gas treatment apparatus for condensing water vapor discharged after the drying operation. The apparatus includes a post combustion chamber. Such a known apparatus uses a gas generated in a heat carrier gas furnace circulated in a completely sealed circulator for the gas produced in the combustion chamber. Therefore, according to this method, the heat carrier gas must be supplied continuously into the circulator.

Such a known device requires a large amount of auxiliary devices such as a dust remover, a blower, a condenser, a heat exchanger, and a post-combustion chamber for water gas combustion.

German Patent Publication No. 24 34 827 describes a method for recovering energy for drying or preheating coal during a gas generating process such as coal gasification or coking. The known method described above is intended to dry and preheat raw material coal with waste heat obtained during dry cooling of coke.

In particular, since the primary closed gas circulator gets heat when cooling hot coke, the primary closed circulator should be equipped with a dust separator. In this case, heat is transferred from the primary closed circuit to a drying medium such as a heat exchanger and an inert gas such as nitrogen, flue gas of coke oven or flue gas obtained from combustion of waste gas. Heat exchangers and dry media are installed in secondary closed gas circulators where dust separators are to be installed. This known method is expensive because of the use of two separate circulators and has a problem of using many expensive components such as heat exchangers, dust separators and blowers.

It is an object of the present invention to provide a method of dry cooling a hot coke discharged from a coke oven device and using the sensible heat of the obtained hot coke to dry and preheat the coal before injecting the coke oven device.

The object of the present invention can be achieved by removing the water vapor in the flue gas before sending the flue gas discharged from the coke oven to the dry chiller of the loaded coke.

The flue gas degassed is passed through a coke dry cooling system containing hot coke to dry cool the hot coke, and the temperature of the flue gas is increased.

The heated flue gas may be passed through a coal preheater containing wet coal to dry and preheat the coal for producing coke. The whole system is completely open so flue gas is not continuously recycled through the system. In other words, the flue gas discharged from the coal preheater is discharged to the outside. The flue gas passes through the coke dry chiller and coal preheater only once. Flue gas is in direct contact with hot cocos in a coke dry cooler and then directly with coal in the drying and preheating unit of the coal.

The flue gas discharged from the coke oven can be directly or indirectly cooled and condensed to remove water vapor contained therein, and the vapor removed flue gas is made inert to the hot coke in the coke dry cooling system. done. Cooling and condensation can be achieved by conventionally known devices.

The present invention eliminates the need for making a special inert gas because the flue gas uses a fully open system that passes through the coke dry chiller and the coal drying and preheater only once. Flue gas can also be made inert by a simple method of removing water vapor.

The present invention utilizes a fully open system, thereby eliminating the need for installing expensive accessories such as heat exchangers and scrubbers, which are required in conventional known closed systems. According to the present invention, the water vapor may be removed from the heat carrier gas, that is, the flue gas, before the coke dry cooling operation, but only a small amount of water vapor may be removed from the conventional method. Therefore, according to the present invention, there is an advantage of using a smaller and cheaper steam removal device, that is, a cooler or a condenser, than that used in the conventional method.

Flue gas from the coke oven system can be subjected to various known pretreatments such as oxygen removal, dust separation or compression by catalytic methods or the like. In carrying out the process of the present invention, necessary pretreatment can be performed according to the apparatus to be used.

Since such pretreatment is well known, a detailed description thereof will be omitted. In a coke oven equipped with a heat exchanger, the flue gas discharged through the heat exchanger does not need to be pretreated with flue gas to remove oxygen. In other words, the coke oven apparatus equipped with an electrothermal heat exchanger burns almost completely, and thus the flue gas produced has a very low oxygen content.

According to another aspect of the present invention, the sensible heat of hot coke can be used more effectively by using part of the sensible heat for steam and electricity generation. In other words, flue gas is used to generate or generate steam by generating a part of the sensible heat of coke carried in flue gas by passing through a conventional well-known steam generator or generator before being discharged from the coke dry cooler and fed to the coal drying and preheating device. Can be. Flue gas is used for drying and preheating the coke-making coal by passing steam generation or passing through a generator and passing it through a coal drying and preheating device.

The above-described aspect of the present invention uses the sensible heat of flue gas, which is also discharged at a temperature of 700-1000 ° C., for steam generation or electricity generation, and uses the sensible heat carried in the flue gas at 150-700 ° C. for drying and preheating coal. There is this. In particular, the use of heat for two purposes has a special function. That is, the high heat of the flue gas is used to generate steam or electricity to effectively use high heat, such as the generation of superheated steam. By using heat for two purposes like this, large loss of residual heat can be avoided. Special arrangements may be used to ensure that flue gases obtain only the sensible heat required to dry preheat coal to the required level. These special devices can be used for steam and electricity generation in addition to the heat required for drying and preheating coal. The excess heat and temperature ranges required for steam or electricity generation and the temperature ranges for drying preheating of the coal depend on the moisture content of the coal. For example, when coal has a low moisture content, a large amount of heat can be used to generate or generate steam. Steam or electricity generated in this way can be used for various purposes, but in the present invention can be used as a power source of the blower for transferring flue gas.

The flue gas discharged from the conventional coke making oven has a temperature of about 250 ° -300 ° C. According to the present invention, the flue gas at this temperature is used as a relatively small cooler and condenser to remove water vapor contained therein. It can be easily cooled and condensed. However, if the flue gas discharged from the coke oven is higher than can be used as it is, the flue gas may be precooled or partially cooled before cooling and condensing the flue gas.

The exhaust temperature of the flue gas emitted from the coke oven apparatus, including the "short heat exchanger" as described in German patent application p 27 15 536.8, is at least 300 ° C, for example about 600 ° C.

Therefore, flue gas must be cooled slightly before cooling and condensing. This partial cooling may be achieved by heat exchanging the flue gas with the combustion air supplied to the coke oven unit or by exchanging heat with the flue gas that has already been cooled and condensed, or by passing the flue gas through a steam generator where It can also be achieved by using part of the heat of steam for steam generation.

Dry coke is wet-cooled again because dry coke cannot be completely prevented during the dry cooling of coke. According to another aspect of the present invention such wet quenching is achieved using condensate produced in cooling and condensation operations and flue gas is conveyed through the system by a blower or suction device installed in an open system.

According to the present invention, the whole system is a single open system, unlike the conventional multiple closed circulation system, and since flue gas is continuously generated in a coke oven and used constantly, the heat carrier gas is used only once in the open circulation system according to the present invention. Passed. Therefore, there is no need to continuously regenerate or recycle the heat carrier gas as in the conventional hermetic device.

In addition, the conventional apparatus is a closed system, so that when the heat carrier gas passes through the drying and preheating device of the coal, it absorbs moisture from the wet coal. Therefore, in order to continuously recycle the heat carrier gas, a large-capacity condenser is installed to remove water vapor. However, according to the present invention, it is open and condenses the flue gas only before coal drying and preheating, so there is an advantage that a relatively small capacity condenser can be installed.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The raw material coal for coke production is supplied to the coal preheater (2), dried and preheated, and then supplied to a known coke production oven including a heat storage unit and a heat exchanger, and the fuel gas and combustion air into the coke oven. Inject. When coke is formed in the coke oven, the hot coke is sent to the coke dry cooler (8) to cool it, and the cooled coke is transferred to the wet cooler (1) to completely cool and then discharged. Since the coke manufacturing process is a conventional method, a detailed description thereof will be omitted.

The present invention is to provide a method of using the sensible heat of hot coke discharged from the oven for producing coke for coke dry cooling in the coke dry cooling device (8) and coal preheating in the coal preheating device (2).

According to the present invention, the flue gas discharged from the regenerator or heat exchanger of the coke oven is supplied to the coke dry cooling device 8 through the blower 13, in which the condenser 14 is removed to remove water vapor in the flue gas. Pass).

The flue gas injected into the dry chiller 8 is in direct contact with the hot coke in the chiller while dry cooling the coke while simultaneously increasing the temperature of the flue gas itself. The heated flue gas is discharged from the cooling device 8, introduced into the coal preheater 2, and then contacted with the wet coal to preheat the coal and then discharged as waste gas.

According to the system of the present invention through which flue gas is passed through a coke dry cooling system (8) and a coal drying and preheating system (2), there is no need to use a separate circulation line as in most known systems, and unlike conventional devices, The entire system can be fully opened, eliminating the need for a device for accumulating or circulating heat exchange gas to continuously exchange heat carrier gas. Such a gas exchanger had to be used essentially in a conventional apparatus using a closed system, and the use of such a system showed many defects.

Also according to the invention the amount of water vapor removed from the flue gas is much less than the amount of water removed from the coal during the coal drying operation. As described above, the system of the present invention is entirely open so that the moisture absorbed in the drying of the wet coal is released into the atmosphere. On the other hand, the conventional system of the closed circulation system has to install a condenser to condense the water vapor absorbed from the heat carrier gas every time the heat carrier gas passes through the coal preheater. In the conventional system, if the water is not condensed after circulating the heat carrier gas, there is a problem that the water content in the heat carrier gas increases. However, according to the present invention, since only a small amount of water may be removed, there is an advantage that a condenser having a smaller capacity than that used in a conventional system can be used.

Flue gas may need to be subjected to a variety of conventional pretreatment operations prior to introduction into the coke dry cooling apparatus 8. For example, when oxygen is removed from the flue gas, a catalytic method or other known method may be used to remove dust or compress the flue gas in addition to oxygen.

Since dust occurs in the coke's dry cooling system, the cooled coke from the dry coke is cooled in the wet quenching machine (1) to prevent dust from being discharged to the outside.

In addition, according to the present invention, the condensate condensed in the cooler and the condenser may be sent to a wet quencher to be used for wet quenching of dry-cooled coke.

The sensible heat of the coke carried by the flue gas from the coke dry cooler can be used to generate some of the steam and power.

In other words, flue gas from a coke cooler including sensible heat of hot coke can be sent to a conventional steam generator or electricity generator 20 to generate steam or electricity.

In this case, the remaining flue gas is sent to the coal preheater 2 to dry and preheat the coal for producing coke moistened by the aforementioned method. The steam generator and generator 20 uses conventional ones known to those skilled in the art.

In the present invention, a portion of steam or electricity generated by using sensible heat may be used as a power source for operating blowers for transferring flue gas. For example, steam from generator 20 may supply electricity to operate the blower.

The use of sensible heat of the heating coke is when the flue gas passing through the steam generator 20 is in the temperature range of about 1000 ° -700 ° C and the exhaust gas passing through the coal preheater 2 is about 700 ° -150 ° C. It is particularly advantageous when in the temperature range of. As such sensible heat is effectively used for different applications, for example, high temperature sensible heat is used in the steam generator for producing hot steam. For example, depending on the moisture content of the raw coal, special equipment should be used to supply the amount of sensible heat necessary to sufficiently preheat the raw coal to the coal preheater and send the remaining sensible heat to the steam generator.

Flue gas is commonly used in the temperature range from the coke oven in the range 250 ° -300 ° C. Under these conditions relatively compact coolers and condensers can be used to remove water vapor from the flue gas.

However, under certain conditions, the flue gas discharged from the coke oven becomes hot, in which case it is desirable to partially conceive the flue gas before sending it to the cooler and condenser. In particular, when the preheat exchanger installed in the oven for coke making is a “short heat exchanger” as described in German Patent Application No. P 27 536.8, the discharge temperature of the flue gas is 300 ° C. or higher, especially about 600 ° C., so it is cooled and condensed. It is desirable to partially cool the flue gas before treatment.

According to one embodiment of the present invention, by passing the flue gas through a steam generator 23 of a known type before passing the flue gas to the cooler and the condenser, some sensible heat of the flue gas is used for steam generation, thereby partially precooling the flue gas and then precooling it. The flue gas may be sent to the cooler and condenser 14. The steam generator 23 uses a well-known conventional thing.

According to another example of the present invention, the flue gas may be cooled by heat exchange with combustion air supplied to the coke oven before sending the cooler and the condenser 14, and then the cooled flue gas may be sent to the cooler and the condenser 14. .

According to another example of the present invention, the flue gas may be heat-exchanged with flue gas that has already been cooled and condensed before being sent to the cooler and condenser 14. In particular, only a part of the flue gas discharged from the cooler and the condenser 14 may be cooled by heat exchange with the hot flue gas, and the pre-cooled flue gas may be transferred to the cooler and the condenser 14.

According to the present invention, unlike in the conventional closed circulation system, the flue gas is passed through the coke cooler (8) while being in contact with the hot coke in an open circulation system and directly in contact with the coal in the preheating and drying device (2) of the coal. Pass it through.

Flue gas is generated continuously and used constantly, circulating several stages of an open circulation system only once. Therefore, the present invention does not need to use a complicated apparatus such as a regenerator or a recirculator used to replenish or replace a heat carrier gas when gas leaks in a conventional system.

In addition, the steam-free flue gas has a low moisture content when it comes into contact with the wet coke-making coal during drying and preheating operation. Therefore, the moisture content of the coal is very high. It is much higher than the air drying process of the known coal, and this high water content ratio is advantageous for the coal drying operation. In addition, according to the present invention, the sensible heat from the hot cocos can be used not only for drying and preheating the coal for producing wet coke, but also for generating or generating steam.

As described above, the method of the present invention not only has the economic advantage of utilizing the waste heat of the solid residues from the coke manufacturing process, but also uses a single heat carrier gas for the entire process, thereby resulting in coke dry cooling operation. The advantage is that there is no need to use a dust separator. Thus, the system of the present invention also has the advantage of being less expensive because it uses smaller components than are needed for a class of devices.

The present invention may be composed of other known parts other than the novel parts described above, that is, known parts.

For example, an oven apparatus for producing coke, which is composed of a coke oven, a heat accumulator, a heat exchanger, and other components, may also be composed of known parts. Coke dry cooler 8, coal preheater 2, wet quencher 1, cooler and condenser 14, steam and electricity generator 20 and submersible generator 23 are also described above. Conventional ones are used except those modified to be necessary for use in the overall system of the present invention.

Claims (1)

Flue gas discharged from the coke making unit is directly contacted with hot coke and coal in the coke dry cooling unit and coal preheating unit, and then discharged to the atmosphere. In the process, flue gas characterized in that the flue gas discharged from the coke oven is directly or indirectly cooled and condensed prior to introduction into the coke dry cooler to remove water vapor contained in the flue gas and then fed to the coke cooler. Drying and preheating method of used coal.

Images