CN113667502A - Coal dry distillation and scrap steel preheating composite equipment and method - Google Patents

Coal dry distillation and scrap steel preheating composite equipment and method Download PDF

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Publication number
CN113667502A
CN113667502A CN202111109747.7A CN202111109747A CN113667502A CN 113667502 A CN113667502 A CN 113667502A CN 202111109747 A CN202111109747 A CN 202111109747A CN 113667502 A CN113667502 A CN 113667502A
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scrap steel
coal
layer
furnace
temperature
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孙中强
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Shenyang Dongda Shanhui Environmental Technology Co ltd
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Shenyang Dongda Shanhui Environmental Technology Co ltd
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    • 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
    • C10B53/00—Destructive distillation, specially adapted for particular solid raw materials or solid raw materials in special form
    • C10B53/04—Destructive distillation, specially adapted for particular solid raw materials or solid raw materials in special form of powdered coal
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
    • B01D53/06—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography with moving adsorbents, e.g. rotating beds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/46—Removing components of defined structure
    • B01D53/54—Nitrogen compounds
    • B01D53/56—Nitrogen oxides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/76—Gas phase processes, e.g. by using aerosols
    • 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
    • C10B57/16—Features of high-temperature carbonising processes
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B5/00—Making pig-iron in the blast furnace
    • C21B5/001—Injecting additional fuel or reducing agents
    • C21B5/003—Injection of pulverulent coal
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/56—Manufacture of steel by other methods
    • C21C5/562—Manufacture of steel by other methods starting from scrap
    • C21C5/565—Preheating of scrap
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2253/00—Adsorbents used in seperation treatment of gases and vapours
    • B01D2253/10—Inorganic adsorbents
    • B01D2253/102—Carbon
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2257/00—Components to be removed
    • B01D2257/20—Halogens or halogen compounds
    • B01D2257/206—Organic halogen compounds
    • B01D2257/2064—Chlorine
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2257/00—Components to be removed
    • B01D2257/30—Sulfur compounds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2257/00—Components to be removed
    • B01D2257/60—Heavy metals or heavy metal compounds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2257/00—Components to be removed
    • B01D2257/70—Organic compounds not provided for in groups B01D2257/00 - B01D2257/602
    • B01D2257/702—Hydrocarbons
    • B01D2257/7027—Aromatic hydrocarbons
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2258/00—Sources of waste gases
    • B01D2258/02—Other waste gases
    • B01D2258/0283—Flue gases

Abstract

The invention discloses a coal dry distillation and scrap steel preheating composite device and a method, belonging to the field of metallurgy. The coal powder is subjected to dry distillation to generate high-temperature dry-distilled coal powder and high-temperature coal gas, the high-temperature dry-distilled coal powder and the high-temperature coal gas enter the shaft furnace through a flue, scrap steel is added into the furnace in batches, the first layer of the scrap steel falls on the bottom of the furnace, then a scrap steel layer is supported by a mechanical arm, the high-temperature coal gas is sent into the furnace through the flue and a connecting branch gas pipe, the periphery of the upper part of the bottom of the furnace enters the furnace, and heat exchange is carried out between the coal powder and the scrap steel of each layer from bottom to top, so that preheated scrap steel is obtained. The device for preheating the scrap steel can comprehensively realize good energy-saving, environment-friendly and carbon-reducing technical effects, and brings considerable economic and social benefits to the steel industry.

Description

Coal dry distillation and scrap steel preheating composite equipment and method
Technical Field
The invention belongs to the field of metallurgy, and particularly relates to coal dry distillation and scrap steel preheating composite equipment and a method.
Background
With the rapid development of the economy of China for many years, the amount of the steel scrap generated by the society is larger and larger, and the steel scrap is not only solid waste, but also resources. At present, two main processes for treating the solid waste are provided: firstly, melting and smelting in an electric furnace; and secondly, melting and smelting by using excess heat of the converter. Electric furnace smelting needs to consume electric energy which is secondary energy, because China still mainly uses thermal power generation at present, about 60% of energy is wasted in the thermoelectric conversion process, and the comprehensive discharge capacity in the power generation process is enlarged. The method for smelting the waste steel with more consumption by utilizing the waste heat of the converter is very reasonable. The waste heat utilization has the advantages of energy conservation, low cost and less emission, and more electric furnaces do not need to be built by investment. However, the amount of residual heat of the converter is limited, and thus the consumption of scrap steel is limited. In order to allow a converter to digest more scrap, steel enterprises mostly adopt a method of heating the scrap at present, and the adopted processes include heating by an oxygen combustion gun of a hot metal ladle, heating by an oxygen combustion gun of a steel ladle and the like. This heating method has a series of problems: the thermal efficiency is low (less than 40%); flue gas can not be well treated, and because the intermittent heating is adopted, the temperature change of the flue gas is extremely large, so that the flue gas can not be denitrated and is limited by the environment, and sulfur, dioxin and heavy metals in the flue gas can not be removed. Therefore, the national environmental protection administration does not allow the process to exist for a long time. At present, a scrap steel preheating device invented by Shijiazhuang huge scientific and technological resources Limited company only performs flue gas dust removal, the patented technology also has problems in the scrap steel discharging link, and the burning loss of the scrap steel is large.
At present, the sintering process of many enterprises still uses anthracite as fuel, and the sintering process uses the anthracite to bring about serious environmental pollution problems. The volatile components of the anthracite coal are not basically burnt in the sintering production process, and all the volatile components are discharged into the atmosphere, so that the atmospheric pollution is caused, and the energy is wasted. In recent years, environmental protection departments in some regions have found that enterprises need to use coke powder or dry distilled coal as sintering fuel to reduce the environmental pollution caused by sintering production. The use of coke powder or dry distillation coal as sintering fuel can greatly reduce the emission pollution caused by sintering production, which is undoubtedly the correct choice of sintering process, but if national sintering enterprises begin to use coke powder or dry distillation coal as sintering fuel, the coke powder yield is far from meeting the demand at present, but the process for producing dry distillation coal at present generally has the problems of high energy consumption and serious pollution.
Disclosure of Invention
The invention aims to overcome the defects in the prior art, and provides a coal dry distillation and scrap steel preheating composite device and method, which are used for realizing the combination of coal dry distillation and scrap steel preheating.
In order to achieve the purpose, the invention adopts the following technical scheme:
a coal dry distillation and scrap steel preheating combined device comprises a coal dry distillation furnace 1 and a scrap steel preheating shaft furnace 2, wherein a heat-preservation scrap steel groove 14 is formed in the bottom of a scrap steel preheating section, an isostatic pressing feeding system 25 is arranged at the top of the furnace, and a manipulator 9 is arranged in the furnace to support scrap steel.
The coal carbonization furnace 1 consists of a combustion chamber 1-1, an oxygen combustion gun 1-2, a carbonization chamber 1-3, a coal injection gun 1-4 and a dust chamber 1-5.
The coal gas retort 1 is connected with the scrap steel preheating shaft furnace 2 through a flue, a branch gas pipe 8 and an annular flue 7 are arranged on the side wall of the scrap steel preheating shaft furnace 2, and the coal gas retort 1 and the branch gas pipe 8 are connected with the scrap steel preheating shaft furnace 2 through the annular flue 7.
The position of the branch gas pipe 8 is far away from the bottom of the scrap steel preheating shaft furnace 2 and has enough height, so that the discharge system at the bottom of the scrap steel preheating shaft furnace 2 is prevented from bearing high temperature. The specific distance depends on the temperature of the high-temperature flue gas entering the furnace and the material selection of the discharging system, so as not to influence the service life of the equipment.
The whole system of the scrap steel preheating shaft furnace 2 runs under negative pressure, gas is not easy to leak, but the gas is prevented from entering during discharging and charging, so that an isostatic pressing discharging system 10 is arranged at the bottom of the furnace, and an isostatic pressing charging system 25 is arranged at the top of the furnace.
The isostatic pressing charging system 25 is composed of a lower closed flap valve 15, a lower charging storage bin 16, an upper closed flap valve 17, an upper charging bin 18 and an upper closed plate 19 which are arranged from bottom to top. Because the upper negative pressure is larger, an upper double-layer feeding bin and a lower double-layer feeding bin are arranged, and an upper sealing flap valve 17 is arranged between the upper feeding bin and the lower feeding bin to strengthen the sealing effect.
The bottom of the scrap steel preheating section is provided with an isostatic pressing discharging system 10, the isostatic pressing discharging system 10 is composed of a flap discharging valve 11 at the bottom of the furnace, a storage bin 12 and a side closing plate 13, and the heat-preservation scrap steel groove 14 is arranged in the storage bin 12.
The number of the mechanical arms 9 is set to be combined with the whole number to be set, preferably 2, and the mechanical arms comprise a first layer of mechanical arms and a second layer of mechanical arms, wherein the material selection of the first layer of mechanical arms requires the heat resistance to be more than 700 ℃; the material selection of the second layer of mechanical arm requires the heat resistance of more than 400 ℃, and 2 mechanical arms are arranged to form three layers of scrap preheating sections in the scrap preheating shaft furnace 2.
The side wall of the scrap steel preheating shaft furnace 2 is connected with a zinc recovery system 3, an inlet of the zinc recovery system is connected to the side wall of the lower portion of the first layer of mechanical arm, and an exhaust of the zinc recovery system is connected to the side wall of the lower portion of the second layer of mechanical arm. The annular flue 20 for leading flue gas and the annular flue 22 for returning flue gas are connected with a bronchus arranged around the shaft furnace in the shaft furnace, the bronchus for leading the annular flue 20 for leading flue gas and connected with the inside of the shaft furnace is arranged between the top of the first layer of waste steel and the first layer of mechanical arm, the bronchus for returning the annular flue 22 for leading the flue gas and connected with the inside of the shaft furnace is arranged between the top of the second layer of waste steel and the second layer of mechanical arm, the annular flue 20 for leading the flue gas is connected with an air inlet of a zinc recovery device 21, and the annular flue 22 for returning the flue gas is connected with an air outlet of the zinc recovery device 21.
The top of the scrap steel preheating shaft furnace 2 is provided with an exhaust port which is specifically arranged between the third layer of scrap steel and the top of the furnace, a dust remover 4, an induced draft fan 5 and a gas tank 6 are arranged behind the exhaust port, and the preheated flue gas is recovered by the gas tank 6 after being dedusted.
A coal dry distillation and scrap steel preheating composite method adopts the equipment and comprises the following steps:
(1) coal powder in the coal retort 1 is subjected to dry distillation to generate high-temperature dry-distilled coal powder and high-temperature coal gas, and the high-temperature coal gas enters the scrap steel preheating shaft furnace 2 through the annular flue 7;
(2) the method comprises the steps of preheating the top of a shaft furnace 2 by waste steel, adding the waste steel into the furnace in batches, enabling the first layer of the waste steel to fall on the bottom of the furnace, supporting the later layer of the waste steel by a manipulator 9, feeding high-temperature coal gas into the waste steel preheating shaft furnace 2 through an annular flue 7 and a connecting branch gas pipe 8, enabling the high-temperature coal gas to enter the furnace around the upper part of the bottom of the furnace, exchanging heat with the waste steel of each layer from bottom to top, obtaining preheated waste steel, and discharging the waste steel to a heat-preservation waste steel groove 14.
In the step (1), the coal gas retort 1 can use self-produced gas as fuel, and can also use other fuel gases. The combustion section is arranged in front of the coal injection section. If the heat value of the fuel gas is not enough, the gradient temperature rise can be realized by adopting a hot blast stove for blast furnace smelting, and if the heat value of the fuel gas meets the requirement, the direct combustion type fuel gas can be adopted.
In the step (1), the high-temperature coal gas has reducibility, and part of iron scale in the scrap steel can be reduced into metallic iron while the scrap steel is heated.
In the step (1), the high-temperature coal gas is purified high-temperature coal gas, and the specific process of the step is as follows: high-temperature flue gas generated by a combustion chamber of the coal carbonization furnace 1 enters a carbonization chamber, coal powder sprayed by a coal spraying gun is firstly carbonized, the volatile gas obtained by carbonization can react with excessive oxygen in the flue gas and carbon dioxide generated by combustion, the coal powder and carbonized coal powder can also react with oxygen and carbon dioxide, moisture in the coal powder can also participate in complex reaction in the furnace, coal gas and carbonized coal dust generated by complex reaction are primarily purified in a dust removal chamber, and the purified high-temperature coal gas is introduced into a shaft furnace to preheat waste steel. The temperature of the smoke discharged from the retort is controlled by controlling the oxygen amount entering the retort, so that the temperature of the smoke discharged from the retort is ensured to be over 1000 ℃, the fully cracking of the volatile components distilled off is ensured, and the heating temperature of the scrap steel is ensured.
The bottom of the dry distillation chamber 1-3 is provided with a dry distillation coal collecting tank 1-6, the dry distillation state of the coal powder is controlled by controlling the coal powder injection flow rate and the coal powder granularity in the coal injection guns 1-4, the coal powder with large particles can not be subjected to dry distillation in a floating state, the coal powder can be subjected to dry distillation continuously when falling into the furnace bottom dry distillation coal collecting tank, the dry distillation process needs large amount of heat, the cooling difficulty of the dry distillation coal can be reduced, the dry distillation generated in the dry distillation coal collecting tank belongs to low-temperature dry distillation, volatile components obtained by dry distillation can still be cracked after entering an upper high-temperature region, smoke discharged from the dry distillation chamber does not contain benzonaphtfen high-gasification point substances, and the dry-method dust removal of the rear smoke can not be influenced; the high-temperature dry distillation coal powder collected by the dry distillation coal collecting tank is cooled indirectly through sectional water cooling, and partial steam and hot water can be recovered. If the combustion-supporting gas adopts oxygen-enriched air, the air can be preheated to cool the dry distillation pulverized coal.
In the step (2), the scrap preheating shaft furnace 2 supports the scrap through the manipulator 9 so as to realize layered heating and layered discharging of the scrap, and the amount of the scrap in each layer is equal to the amount of the added steel in the converter every time, so that the operation is convenient.
In the step (2), the second layer of scrap steel is supported by the first layer of mechanical arm, after the high-temperature smoke is preheated by the first layer of scrap steel, the obtained smoke temperature after primary preheating does not exceed 700 ℃, so that the material of the first layer of mechanical arm is selected to resist heat of more than 700 ℃, and the heat-resistant steel can bear the heat. After the second layer of scrap steel is preheated, the obtained flue gas temperature after secondary preheating does not exceed 400 ℃, so that the material of the second layer of manipulator can resist heat of more than 400 ℃; after three layers of waste steel are preheated, the obtained flue gas temperature after three times of preheating is generally at 130-180 ℃, and flue gas treatment and dust removal can be carried out; the flue gas temperature of each layer is also determined by the amount of scrap in each layer, which depends on the converter capacity, the molten iron temperature, the type of steel being smelted, which is taken into account in the design as a basis for determining the diameter of the shaft furnace. If the exhaust gas temperature is too high, the height of the shaft furnace is increased, and a manipulator and a preheating material layer are added.
The bottom material of the scrap preheating shaft furnace 2 is required to resist heat above 700 ℃, because hot flue gas flows upwards along the shaft furnace, the heating temperature of a steel tapping system at the bottom of the shaft furnace is approximately equal to the temperature of the bottom of the second layer of scrap, and the temperature of the scrap generally does not exceed 700 ℃, so the bottom material of the shaft furnace can resist heat only if the temperature of the scrap is 700 ℃. The design has the advantages that the first layer of mechanical arm does not bear high temperature, the material of the mechanical arm is easier to select, the maintenance cost of the equipment is reduced, and the operation of the equipment is more stable. The furnace bottom does not bear high temperature, and the material selection of the furnace bottom equipment is more economical.
In the step (2), the scrap steel is fed into the scrap steel preheating shaft furnace 2 in batches through the isostatic pressing feeding system 11, and the specific process is as follows: the scrap steel is firstly added into the upper feeding bin 18, then the upper closing plate 19 is closed, the upper flap valve 17 is opened, the scrap steel falls into the lower feeding bin 16, the flap valve 17 is closed, the lower flap valve 15 is opened when the material is fed into the shaft furnace, and the flap valve 15 is closed after the scrap steel falls. The upper seal is always in a double seal state. Protective gas can be filled into the feeding bin for safety;
in the step (2), the preheated scrap steel is discharged layer by layer through the isostatic pressing discharging system 10, and the specific process is as follows: in order to ensure safety, protective gas is blown into the storage bin 12 for protection during discharging, the flap valve 11 is opened firstly during discharging, the first layer of scrap steel is discharged into the heat-preservation scrap steel groove 14 in the storage bin, the flap valve is closed, protective gas is blown into the storage bin in an increasing mode, the side sealing door 13 is opened, the heat-preservation scrap steel groove 14 is taken out, the side sealing door is closed, the blowing amount of the protective gas is reduced, and the micro-positive pressure in the storage bin is ensured;
in the step (2), the discharging, charging and discharging processes of the scrap steel from the scrap steel preheating shaft furnace 2 are as follows: opening a turnover plate discharge valve 11, discharging a first layer of scrap steel in the scrap steel preheating shaft furnace 2 to a heat preservation scrap steel groove 14 in a storage bin 12, closing the turnover plate discharge valve 11, opening a side sealing door 13, taking out the scrap steel, closing the side sealing door 13, withdrawing a first layer of mechanical arm after closing the turnover plate discharge valve 11, discharging a second layer of scrap steel to the furnace bottom, recovering the first layer of mechanical arm to a supporting state, withdrawing a second layer of mechanical arm, discharging a third layer of scrap steel to the first layer of mechanical arm, recovering the second layer of mechanical arm to the supporting state, opening a lower sealing turnover plate valve 15, and adding the scrap steel in a lower charging bin to a second layer of mechanical arm in the shaft furnace.
The working principle of the invention is as follows:
coal is subjected to dry distillation at the high temperature of over 1100 ℃, the volatile components of the coal subjected to dry distillation can be cracked at the high temperature, the presence of the beninafene substances in the coal gas is avoided, and the generated coal gas is convenient to recycle. However, the coal gas after dry distillation has high temperature, the heat is only used for producing steam for power generation at present, and the energy utilization rate is low. If low-temperature dry distillation is adopted, a series of environmental protection problems are caused, and environmental protection approval is difficult to pass. If coal dry distillation and waste steel preheating are combined together, coal dry distillation is carried out in a high-temperature section, the medium-temperature coal gas after coal dry distillation is just used for preheating the waste steel, and the medium-temperature coal gas after coal dry distillation preheating the waste steel does not oxidize the waste steel and can reduce iron oxide scales of the waste steel into metal iron. The waste steel preheating process just reduces the temperature of the medium-temperature coal gas, thereby avoiding the consumption of the coal gas cooling water in the traditional process and avoiding the generation of waste water and tar pollutants. The reducing atmosphere preheats the scrap steel, and can realize the zinc recovery in the scrap steel in a metal state. The coal gas generated by dry distillation of coal not only can meet the use requirement of the process, but also can be used by other processes due to the residual coal gas.
The shaft furnace is the best heat transfer equipment in all industrial furnaces. Therefore, the shaft furnace is adopted as scrap steel preheating equipment in the technology, and the heat source is from the coal carbonization furnace.
If the high-zinc light and thin material waste steel is preheated frequently, the enrichment of zinc steam in the shaft furnace can be caused, therefore, the smoke is partially led out in the temperature range of 600-750 ℃, the smoke is subjected to zinc recovery treatment by a specially-made zinc recovery device, the smoke after zinc recovery is sent back to the shaft furnace to be continuously preheated, the zinc steam which is not recovered in the smoke can be sent back to the furnace and captured by the upper low-temperature waste steel, and the zinc steam is generated again in the descending process of the waste steel and enters the next recovery.
Because the shaft furnace is in reducing atmosphere, the nitrogen oxides can be reduced by reducing gas in the flue gas, and therefore the nitrogen oxides in the flue gas can be very low. And part of dry distillation coal powder in the flue gas escapes to the rear part, and the dry distillation coal powder is good active carbon and can remove harmful substances such as sulfur, dioxin, benzopyrene, heavy metals and the like in the flue gas. If the smoke can not reach the standard, a secondary blowing dry distillation coal powder adsorption device can be arranged at the rear part of the shaft furnace, and the dry distillation coal powder can remove harmful substances such as sulfur, dioxin, benzopyrene, heavy metals and the like in the smoke. The injected dry distillation coal powder and the dust in the furnace are captured together in a rear dust remover. The dust and the dry distillation coal dust recovered by the dust remover can be sent to a blast furnace coal injection system, and are injected into the blast furnace along with the injected coal dust, so that resource utilization and harmless treatment are realized.
The scrap steel preheating shaft furnace 2 is provided with an injection dry distillation pulverized coal adsorption device so as to ensure that the flue gas of the scrap steel preheating shaft furnace 2 is discharged up to standard.
The invention has the technical effects that:
the waste steel preheating composite equipment for coal carbonization and waste steel preheating can comprehensively realize good energy-saving, environment-friendly and carbon-reducing technical effects and bring considerable economic and social benefits to the steel industry.
Drawings
Fig. 1 is a schematic structural diagram of a coal carbonization and scrap steel preheating combined equipment device in embodiment 1 of the present invention, wherein:
1-coal gas retort, 1-2 oxygen combustion gun, 1-3 dry distillation chamber, 1-4 coal injection gun, 1-5 dust removal chamber, 1-6 dry distillation coal collection tank, 2-scrap preheating shaft furnace, 3-zinc recovery system, 4-dust remover, 5-induced draft fan, 6-gas tank, 7-annular flue, 8-branch gas pipe, 9-mechanical arm, 10-isostatic pressure discharge system, 11-flap discharge valve, 12-storage bin, 13-side closing plate, 14-heat preservation scrap steel tank, 15-lower closed flap valve, 16-lower feeding storage bin, 17-upper closed flap valve, 18-upper feeding bin, 19-upper closing plate, 20-flue gas annular flue, 21-zinc recovery device, 22-flue gas return annular flue, 23-zinc outlet valve, 24-cooling system and 25-isostatic pressing feeding system. 1-1 combustion chamber.
Detailed Description
Example 1
A certain steel mill is provided with two 100-ton converters, and because the yield of molten iron of a blast furnace is limited, the steel yield of the converters cannot meet the requirements of a continuous casting machine, and broken casting is often caused. In order to increase the output of the converter, more scrap steel is added, and enough scrap steel cannot be added due to the limitation of heat balance, so a ladle oxygen combustion gun is adopted to preheat the scrap steel, and the converter is shut down due to the overproof of smoke nitrogen oxides, sulfur and dioxin. Meanwhile, the sintering process adopts anthracite as sintering fuel, the emission of VOCs is seriously overproof, local environmental protection departments require that coke powder, dry distillation coal powder or blue carbon powder without volatile components are adopted as sintering fuel, the local coke powder cannot meet the requirement, the remote transportation cost of blue carbon powder is high, the price of blue carbon powder rises in winter, the transportation cannot be guaranteed, the dry distillation coal powder is produced by the method, and the traditional method is difficult to carry out environmental protection and approval, so the patent technology is adopted.
A coal dry distillation and scrap steel preheating combined equipment device is shown in a schematic structural diagram in figure 1, the detailed structure is recorded in the content part of the invention, a coal dry distillation furnace 1 is arranged, and gas generated by the process is used as fuel gas to support combustion through total oxygen. The coal is low-ash low-sulfur coal with local volatile matter of 18 and calorific value of 6000 kcal/kg. A waste steel preheating shaft furnace 2 is arranged behind the coal carbonization furnace 2, the shape of the shaft furnace is designed to be square, the effective section in the furnace is 2 meters square, the average bulk density of the waste steel is 2 tons/cubic meter, the designed loading capacity of each layer of waste steel is 40 tons, a first layer of manipulator is arranged at a position 5.5 meters away from a furnace bottom discharging flap valve, a second layer of manipulator is arranged at a position 11 meters away from the furnace bottom discharging flap valve, and a closed flap valve 15 under a furnace top isostatic pressure feeding system is arranged at a position 18 meters away from the furnace bottom flap valve;
the furnace top isostatic pressing charging system 25 is provided with a lower charging storage bin 16 and an upper charging storage bin 18, an upper sealed discharging flap valve 17 is arranged between the upper and lower storage bins, the top of the upper storage bin 18 is sealed by an upper sealing plate 19, and the upper and lower storage bins are protected by nitrogen gas under micro-positive pressure;
the furnace bottom discharging system has lower negative pressure and is provided with single isostatic pressing seal, the bottom of the shaft furnace is provided with a flap discharging valve 11, a storage bin 12 and a side sealing plate 13, the storage bin 12 is internally provided with a heat preservation waste steel groove 14, and the storage bin is provided with nitrogen micro-positive pressure protection;
an annular flue 7 is arranged at the bottom of the shaft furnace, the height of the annular flue 7 is 0.4 m from the bottom of the shaft furnace to a connecting branch gas pipe 8, high-temperature coal gas of the retort is distributed to the branch gas pipe 8 through the annular flue 7 and enters waste steel of the shaft furnace after heat, the temperature of the coal gas discharged by the retort is controlled to be about 1100 ℃, and the average preheating temperature of the waste steel is controlled to be 800-;
the zinc recovery system bleed gas bronchus is arranged at the lower part of the first layer of manipulator, the led-out smoke is sent into the zinc recovery device 21 through the annular flue 20, the smoke enters the annular flue 22 from the exhaust port after zinc removal, and is sent back into the furnace through the bronchus to continue preheating the scrap steel. The branch gas pipe returning the flue gas is arranged at the lower part of the second layer of manipulator, and the flue gas self-circulates by the upper and lower pressure difference without external force; the recovered metal zinc is discharged through a zinc discharge valve 23 at regular intervals;
the equipment runs for half a year, mainly uses scrap steel preheating operation, and the average temperature of the scrap steel entering the converter is 740 and 760 ℃; the adding amount of the waste steel in each furnace exceeds 35 tons, and is increased by 15 tons compared with the adding amount of the waste steel in each furnace in the prior waste steel preheating process, the continuous casting process requirement is met, and the blank drawing speed can be improved; the waste steel has no burning loss; the scrap steel is discharged 40-45 times every day, and about 1500 tons of scrap steel are preheated, so that the production of one converter can be met. Recovering about 15 tons of zinc per day on average; about 550 tons of consumption per day and about 420 tons of dry distillation coal powder are produced per day, about 50 percent of coal gas generated by the system is used by oneself, and the rest coal gas is used for generating electricity in a self-contained power plant;
the project has the advantages that:
because the waste steel is preheated by the waste heat of coal dry distillation, the energy consumption for preheating the waste steel is saved;
because the high-temperature coal gas is used for preheating the scrap steel, the scrap steel is not burnt, and the burning loss of the scrap steel can be reduced by about 2 ten thousand tons every year in the project;
about 2000 tons of metal zinc are recovered in the project every year;
the green sintering fuel is produced by about 14 ten thousand tons every year, and the sintering process can reduce the emission of VOCs by more than ten thousand tons every year;
because the fuel can be purchased on site to ensure safer production, the fuel cost is lower than that of external purchase;
because the coal adopts the high-temperature dry distillation process, no chemical wastewater is generated, no waste gas is discharged, and the investment is far less than that of the traditional process;
because scrap steel is adopted for preheating, about 20 ten thousand tons of scrap steel are consumed by a single furnace every year, and about 20 ten thousand tons of steel are produced. Compared with the arc furnace interruption process, the method reduces the emission of carbon dioxide by about 10 ten thousand tons, and compared with the long-process smelting, the method reduces the emission of carbon dioxide by 40 ten thousand tons;
the technical scheme of the invention can realize good energy-saving, environment-friendly and carbon-reducing technical effects and can bring considerable economic and social benefits to the steel industry.

Claims (10)

1. The utility model provides a coal dry distillation and scrap steel preheat combination equipment, its characterized in that, preheats the shaft furnace including coal retort and scrap steel, scrap steel preheating section bottom be equipped with the heat preservation scrap steel groove, the furnace roof is equipped with isostatic pressing charging system, establish the manipulator in the stove and hold in the palm the scrap steel, wherein:
the coal gas retort is connected with a flue for the scrap steel preheating shaft furnace, a gas branch pipe and an annular flue are arranged on the side wall of the scrap steel preheating shaft furnace, and the coal gas retort and the gas branch pipe are connected with the scrap steel preheating shaft furnace through the annular flue.
2. The coal dry distillation and scrap steel preheating combined equipment according to claim 1, wherein:
the coal carbonization furnace consists of a combustion chamber, an oxygen combustion gun, a carbonization chamber, a coal injection gun and a dust chamber, wherein the bottom of the carbonization chamber is provided with a carbonization coal collecting tank;
the isostatic pressing feeding system consists of a lower closed flap valve, a lower feeding storage bin, an upper closed flap valve, an upper feeding bin and an upper closed plate which are arranged from bottom to top at one time;
the bottom of the scrap steel preheating section is provided with an isostatic pressing discharging system, the isostatic pressing discharging system consists of a flap discharging valve at the bottom of the furnace, a storage bin and a side sealing plate, and the heat-preservation scrap steel groove is arranged in the storage bin.
3. The coal dry distillation and scrap steel preheating combined equipment according to claim 1, wherein;
the number of the mechanical arms is 2, the mechanical arms comprise a first layer of mechanical arms and a second layer of mechanical arms, and the material selection of the first layer of mechanical arms requires the heat resistance to be more than 700 ℃; the material selection of the second layer of mechanical arm requires the heat resistance of more than 400 ℃, and 2 mechanical arms are arranged to form three layers of scrap steel preheating sections in the scrap steel preheating shaft furnace;
the furnace top of the scrap steel preheating shaft furnace is provided with a smoke outlet which is specifically arranged between the third layer of scrap steel and the furnace top, and a dust remover, an induced draft fan and a gas chamber are arranged behind the smoke outlet.
4. The coal dry distillation and scrap steel preheating combined equipment according to claim 1, wherein a zinc recovery system is connected to the side wall of the scrap steel preheating shaft furnace, an inlet of the zinc recovery system is connected to the side wall of the lower part of the first layer of manipulator, and an exhaust of the zinc recovery system is connected to the side wall of the lower part of the second layer of manipulator, and specifically, the zinc recovery system comprises an annular flue for leading flue gas, a zinc recovery device, an annular flue for returning flue gas, a zinc outlet valve and a cooling system; the annular flue for leading flue gas and the annular flue for returning flue gas are connected with a bronchus arranged around the shaft furnace in the shaft furnace, the bronchus for leading the annular flue for leading flue gas and connected with the inside of the shaft furnace is arranged between the top of the first layer of waste steel and the first layer of mechanical arm, the bronchus for returning flue gas and connected with the inside of the shaft furnace is arranged between the top of the second layer of waste steel and the second layer of mechanical arm, the annular flue for leading flue gas is connected with an air inlet of a zinc recovery device, and the annular flue for returning flue gas is connected with an air outlet of the zinc recovery device.
5. A coal dry distillation and scrap steel preheating composite method, which adopts the coal dry distillation and scrap steel preheating composite equipment of any one of claims 1 to 4, is characterized by comprising the following steps:
(1) performing dry distillation on coal powder in the coal dry distillation furnace to generate high-temperature dry-distilled coal powder and high-temperature coal gas, and enabling the high-temperature coal gas to enter a scrap steel preheating shaft furnace through an annular flue;
(2) the method comprises the steps of preheating the top of a shaft furnace by scrap steel, adding the scrap steel into the furnace in batches, enabling the first layer of the scrap steel to fall on the bottom of the furnace, supporting the later scrap steel layer by a mechanical arm, feeding high-temperature coal gas into the scrap steel preheating shaft furnace through an annular flue and a connecting branch gas pipe, enabling the high-temperature coal gas to enter the furnace around the upper part of the bottom of the furnace, exchanging heat with the scrap steel of each layer from bottom to top, obtaining preheated scrap steel, and discharging the preheated scrap steel to a heat-preservation scrap steel groove.
6. The coal dry distillation and scrap steel preheating combined method according to claim 5, wherein in the step (1), the high-temperature coal gas has reducibility, and part of iron scales in the scrap steel can be reduced into metallic iron while the temperature of the scrap steel is raised.
7. The coal dry distillation and scrap steel preheating composite method according to claim 5, wherein in the step (1), the high-temperature coal gas is purified high-temperature coal gas, and the specific process of the step is as follows: after high-temperature flue gas generated by a combustion chamber of the coal gas retort enters a dry distillation chamber, firstly, pulverized coal sprayed by a coal spraying gun is subjected to dry distillation, dry-distilled volatile matter gas reacts with surplus oxygen in the flue gas and carbon dioxide generated by combustion, the pulverized coal and the dry-distilled pulverized coal react with the oxygen and the carbon dioxide, moisture in the pulverized coal can participate in the reaction in the furnace, coal gas and dry-distilled coal dust generated by the reaction are primarily purified in a dust removal chamber, the purified high-temperature coal gas is introduced into a shaft furnace to preheat waste steel, the temperature of the dry-distilled flue gas in the furnace is controlled by controlling the amount of the oxygen entering the furnace, the temperature of the dry-distilled flue gas discharged from the dry distillation furnace is ensured to be above 1000 ℃, the full cracking of the dry-distilled volatile matter is ensured, and the heating temperature of the waste steel is ensured.
8. The coal dry distillation and scrap steel preheating combined method according to claim 5, wherein in the step (2):
the scrap steel preheating shaft furnace supports scrap steel through a manipulator, so that the layered heating and layered discharging of the scrap steel are realized, the amount of the scrap steel of each layer is equal to the amount of the scrap steel added in each time of the converter, and the operation is convenient;
the second layer of scrap steel is supported by the first layer of manipulator, the temperature of the flue gas obtained after primary preheating is less than or equal to 700 ℃ after the high-temperature flue gas is preheated to the first layer of scrap steel, and the material of the first layer of manipulator resists heat at the temperature of more than 700 ℃; after the second layer of scrap steel is preheated, the obtained secondary preheated smoke temperature is less than or equal to 400 ℃, and the material of the second layer of manipulator resists heat at the temperature of more than 400 ℃; after three layers of waste steel preheating, the obtained flue gas temperature after three times of preheating is at 130-180 ℃, and the flue gas temperature is used for flue gas treatment and dust removal;
the bottom material of the scrap steel preheating shaft furnace is required to resist heat above 700 ℃;
the method is characterized in that the scrap steel is fed into a scrap steel preheating shaft furnace in batches through an isostatic pressing feeding system, and the specific process is as follows: the method comprises the following steps that firstly, steel scraps are added into an upper feeding bin, then an upper closing plate is closed, an upper flap valve is opened, the steel scraps fall into a lower feeding bin, the flap valve is closed, when the steel scraps are fed into a shaft furnace, the lower flap valve is opened, the flap valve is closed after the steel scraps fall, the upper portion of the flap valve is always in a double-closed state, and protective gas is filled into the feeding bin to ensure safety;
the waste steel after preheating is discharged layer by layer through an isostatic pressing discharging system, and the specific process is as follows: protective gas is injected into the storage bin for protection during discharging, the flap valve is opened firstly during discharging, the first layer of scrap steel is unloaded into the heat-preservation scrap steel groove in the storage bin, the flap valve is closed, protective gas is injected into the storage bin in an increasing mode, the side sealing door is opened, the heat-preservation scrap steel groove is taken out, the side sealing door is closed, the injection amount of protective gas is reduced, and the micro positive pressure in the storage bin is guaranteed.
9. The coal dry distillation and scrap steel preheating combined method according to claim 5, wherein in the step (2), the discharging, charging and discharging processes of the scrap steel from the scrap steel preheating shaft furnace are as follows: opening a turnover plate discharge valve, discharging a first layer of scrap steel in a scrap steel preheating shaft furnace to a heat-preservation scrap steel groove in a storage bin, closing a turnover plate discharge valve, opening a side sealing door, taking out the scrap steel, closing the side sealing door, withdrawing a first layer of manipulator after closing the turnover plate discharge valve, discharging a second layer of scrap steel to a furnace bottom, recovering the first layer of manipulator to a supporting state, withdrawing a second layer of manipulator, discharging a third layer of scrap steel to the first layer of manipulator, recovering the second layer of manipulator to the supporting state, opening a lower sealing turnover plate valve, and adding the scrap steel in a lower feeding bin to the second layer of manipulator in the shaft furnace.
10. The coal carbonization and scrap steel preheating combination method according to claim 5, characterized in that the coal powder carbonization state is controlled by controlling the coal powder injection flow rate and the coal powder particle size in the coal injection gun, coal powder with large particles can be carbonized but not finished in a floating state, carbonization is continued when the coal powder falls into a furnace bottom carbonization coal collecting tank, a large amount of heat is required in the carbonization process to reduce the temperature reduction difficulty of carbonization coal, carbonization in the carbonization coal collecting tank is low-temperature carbonization, volatile components obtained by carbonization enter an upper high-temperature region and then are cracked, and after detection, no phenylnaphthylene high-gasification point substances exist in the smoke discharged from the carbonization chamber; the high-temperature dry distillation coal powder collected by the dry distillation coal collecting tank is cooled indirectly through sectional water cooling so as to recover partial steam and hot water.
CN202111109747.7A 2021-09-18 2021-09-18 Coal dry distillation and scrap steel preheating composite equipment and method Pending CN113667502A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202111109747.7A CN113667502A (en) 2021-09-18 2021-09-18 Coal dry distillation and scrap steel preheating composite equipment and method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202111109747.7A CN113667502A (en) 2021-09-18 2021-09-18 Coal dry distillation and scrap steel preheating composite equipment and method

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CN113667502A true CN113667502A (en) 2021-11-19

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Application Number Title Priority Date Filing Date
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Country Link
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