RU2605024C2 - Upper gas inlet purification system - Google Patents

Abstract

FIELD: processing and recycling wastes; metallurgy.

SUBSTANCE: invention relates to upper gas inlet system for dry purification of flue gas of the electrolytic aluminum manufacturing. System comprises a dust remover, the bottom of which is communicated with a front collection pipe of the dust remover through an air-intake pipe of the dust remover, reactor, which is arranged at the air-intake pipe of the dust remover, alumina distributing device, which is arranged between the reactor and a fresh alumina storage cabin and communicated with the reactor through a distributing chute, alumina feeding device, which is arranged between the alumina distributing device and the fresh alumina storage cabin, fluorine-containing alumina storage cabin, return chute, material lifting device through a return chute, export collection pipe, chimney, air blower and exhaust pipe, upper part of the dust remover is communicated with an export collection pipe of the dust remover, and export collection pipe of the dust remover is communicated with a chimney through an air blower, pipeline is located below the dust remover, there is a return feeding tube connected to the alumina lifting device through the return chute and to the fluorine-containing alumina storage cabin.

EFFECT: reduced capital investments, higher efficiency, reduced power consumption of the system.

15 cl, 2 dwg

Description

FIELD OF THE INVENTION

The present invention relates to a cleaning system, in particular to a cleaning system with a lower gas supply, for dry cleaning of electrolysis exhaust gas in the electrolytic aluminum industry.

BACKGROUND

In the aluminum electrolytic industry, the process for producing aluminum by electrolysis requires an alumina melt as an electrolyte, and carbon material is required as an electrode for electrolysis. Liquid aluminum is deposited at the cathode, and anode gas is generated at the anode, with CO ₂ as the main component. However, air pollutants also stand out, with hydrogen fluoride, fluorides and dust as the main components, and these gases and anode gas are collectively referred to as electrolysis exhaust gas.

Electrolysis exhaust gas filling the electrolysis shop inside worsens the operating mode and seriously damages the physical health of the employee. Electrolysis flue gas extends beyond the factory zone and causes serious harm to the development of agriculture and livestock production and people's lives. According to the requirements set forth in the Chinese State Standard GB25465-2010 [Standard for Emissions of Pollutants in the Aluminum Industry], electrolysis waste gas must be processed and discharged in accordance with the standard. However, fluorides in electrolysis flue gas are also important raw materials for electrolysis production and have great economic benefits in their disposal. Consequently, the electrolytic aluminum industry must be equipped with an exhaust gas purification system.

The electrolysis exhaust gas purification system has various configurations, depending on the local situation and the requirements for the operating mode. In the past, as a rule, mass production with electrolysis with an annual output of 50-60 thousand tons was supplied with one set of treatment system, which was quite small and simple in this configuration. Currently, with the expansion of the scale of production, aluminum mass production with an annual production capacity of 100-130 thousand tons or more, as a rule, is provided by one set of exhaust gas purification system. The exhaust gas purification system mainly covers the following three forms: (1) 20-32 reverse blowing dust cleaners + 20-32 reactors + 2-6 sets of main exhaust fans; (2) 28-32 pulse dust cleaners + 28-32 reactors + 2-6 sets of main exhaust fans; (3) 28-32 pulse dust cleaners with a bag filter for preliminary separation + 28-32 reactors + 3-4 sets of main exhaust fans. However, the first two system configurations mentioned above have disadvantages such as reduced redundancy between systems, unstable gas flow, increased area under equipment, increased cost, increased operation and maintenance costs and increased power consumption, and, most importantly, - the difficulty in further improving the efficiency of purification of exhaust gas. In the third configuration, the flue gas mainly enters the dust cleaner from the side walls, the reactors are mounted in higher places, so that the access point of fresh alumina in the treatment system is higher and the effective volume of the storage hopper is reduced; however, the rectangular large pipe for flue gas at the outlet of the dust cleaner is high, and there is a need to install it on the roof or side walls of the dust cleaner. Since the vibration of the pipe violates the stability of the entire system and the configuration of the mentioned cleaning system, the inlet valve and outlet valve and bag-type filters of the dust cleaner in this configuration of the cleaning system become inconvenient for inspection and maintenance, and the electromagnetic pulse valve is located outdoors and is also inconvenient for inspection and maintenance.

The above three configurations of systems need additional modification and improvement, in circumstances dictated by constantly increasing environmental standards, increasing requirements of workers in electrolytic aluminum smelting plants regarding labor intensity, working conditions and system safety, and therefore the state pays special attention to rational use energy, reduce emissions and protect the environment.

SUMMARY OF THE INVENTION

To address the above problems, the present invention provides a cleaning system with a bottom gas supply, the purpose of which is to increase the stability of the system, reduce the design time, save investment, reduce operating costs, facilitate maintenance, increase cleaning efficiency and extend the life of the device.

To achieve the above goal, the present invention is embodied as follows: a cleaning system with a bottom gas supply is designed so that it consists of: a dust cleaner, the bottom of which communicates with the front collector of the dust cleaner through the gas supply pipe of the dust cleaner, the gas supply pipe of the dust cleaner is equipped with a multipoint type reactor, means alumina located between the multipoint type reactor and the storage hopper for fresh alumina, moreover, Alumina separation is communicated with a multipoint type reactor through a distribution chute, alumina supply means provided between alumina distribution means and a storage bin for fresh alumina, a return pipe inlet located below the dust cleaner, a return pipe is connected to a material lifting means through a return chute, and then connected to a hopper for the accumulation of fluorine-bearing alumina, and the upper part of the dust cleaner communicates with the output collector yleochistitelya pyleochistitelya through the exhaust pipe, and the outlet manifold pyleochistitelya connected to the exhaust pipe via a blower.

A bottom gas cleaning system is a type of cleaning system located in one row, or one after another, or in several rows.

A dust cleaner is a type of bag filter dust cleaner.

The dust cleaner repair area is located above the dust cleaner.

The lifting means is located at the top of the repair area of the dust cleaner.

A separation wall is provided on the ash bin section below the dust cleaner.

The waterproof canopy is located above the side wall of the dust cleaner repair section, and the dust cleaner maintenance platform is located below the side wall of the dust cleaner repair section.

A cyclic loading chute is located between the bottom of the dust cleaner and the multipoint reactor.

The gas supply pipe of the dust cleaner between the multi-point reactor and the front dust collector manifold is provided with an inlet valve for the dust cleaner.

The exhaust pipe of the dust cleaner is equipped with an exhaust valve for the dust cleaner.

An impurity removal means is provided between the alumina feed means and the storage tank for fresh alumina.

Alumina measuring means are located below the alumina feeding means.

The alumina distribution means communicates with the alumina feed means through a fresh material chute.

The material lifting means is connected to the material lifting means.

The lifting means for venting the material is a Roots blower.

The bottom of the dust cleaner, the alumina distribution means and the return chute are connected to one end of the ventilation pipe, and the other end of the ventilation pipe is connected to the ventilation means.

A fresh material chute is connected to one end of the ventilation pipe, and the other end of the ventilation pipe is connected to the ventilation means.

The present invention has the following advantages: (1) when using a gas supply from the bottom, the overall height of the cleaning system is reduced, investment is saved, and the stability of the system is increased; (2) when using a gas supply from the bottom, the width of the treatment system is reduced, structural steel structures are preserved, and the total capital investment in the system is reduced; (3) when using a gas supply from the bottom, the total pressure of the cleaning system is reduced, and finally, the energy consumption of the system is reduced; (4) when using a gas supply from the bottom, the monorail valve is configured at the top of the dust cleaner so that the frame and bag filter of the dust cleaner can be maintained outdoors, thus addressing the problem of overheating of the operating environment when replacing the bag filter of the dust cleaner, providing for single-segment manufacture and installation of a dust cleaner frame, and increased efficiency; (5) the effect of mixing the gas and solid phases is enhanced, and thus the cleaning effect is enhanced by the use of a multipoint or center-center reactor, or a VRI reactor, or a Venturi reactor or other types of gas and solid phase mixing devices; (6) the resistance at the inlet of the dust cleaner and exhaust pipes is reduced, and the position of the valve facilitates maintenance; (7) the exhaust pipe of the dust cleaner reduces the resistance of the pipes before and after the blower, facilitates the oscillation of the pipe and reduces the adverse effect on the dust cleaner frame; (8) by using a device for supplying fresh alumina and optimizing the creation of molds, fresh alumina can be supplied uniformly, stably and in fixed quantities; (9) through measures such as a noise isolation chamber, noise generating devices in the cleaning system, such as a high-pressure centrifuge and a Roots blower, can be controlled centrally, and noise pollution in the work area can be reduced. The cleaning system has the advantages of less footprint, lower system resistance, even distribution of gas flow, low power consumption, easy maintenance of the valves and bag filter, low noise, high system stability, lower interference with fresh alumina feed and a higher hopper volume for fresh alumina.

The present invention can save investment, increase efficiency, shorten the design period, reduce system power consumption, facilitate maintenance and improve system stability, and has wide prospects for market applications.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a cross section of a cleaning system with a lower gas supply according to the present invention, the components of which are located next to each other.

FIG. 2 is a block diagram of a bottom gas purification system according to the present invention, the components of which are adjacent to each other.

In the figures, reference number 1 means a dust cleaner; 2 - repair section of the dust cleaner; 3 - lifting means; 4 - waterproof canopy; 5 - a dust cleaner maintenance platform; 6 - cyclic loading chute; 7 - inlet return pipe; 8 - gas pipe of the dust cleaner; 9 - reactor; 10 - inlet valve of the dust cleaner; 11 - a front collector of a dust cleaner; 12 - exhaust pipe of the dust cleaner; 13 - dust valve outlet valve; 14 - return trough; 15 - gutter for fresh material; 16 - dust collector output collector; 17 - distribution chute; 18 - storage hopper for fresh alumina; 19 - a hopper for the accumulation of fluorine-bearing alumina; 20 - means for removing impurities; 21 - alumina feed means; 22 - a means of measuring alumina; 23 - a means of distributing alumina; 24 - pipeline means for compressed air; 25 - means of lifting material; 26 - lifting means for venting material; 27 - ventilation means; 28 - blower; 29 - exhaust pipe; 30 - ash bin section.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention will now be described in detail with reference to the figures, but the scope of protection of the present invention is not limited to that illustrated in the figures.

The lower gas supply cleaning system according to the present invention, as schematically illustrated in FIGS. 1 and 2, is constructed in such a way as to be composed of: a dust cleaner 1, the bottom of which communicates with a front dust collector 11 through a gas supply pipe of the dust cleaner 8, the front dust collector collector 11 is located below the gas pipe of the dust cleaner 8; a gas supply pipe of a dust cleaner 8 provided with a reactor 9, wherein the alumina distribution means 23 is provided between the reactor 9 and the storage tank for fresh alumina 18, the alumina distribution means 23 communicates with the reactor 9 through a distribution chute 17, the alumina supply means 21 is provided between the alumina distribution means 23 and storage hopper for fresh alumina 18, the inlet return pipe 7 is located below the dust cleaner 1, the inlet return pipe 7 is connected to the lifting means material 25 through the return chute 14, and then connected to the hopper for the accumulation of fluoride-bearing alumina 19, the upper part of the dust cleaner 1 communicates with the output collector of the dust cleaner 16 through the exhaust pipe of the dust cleaner 12, and the output manifold of the dust cleaner 16 is connected to the exhaust pipe 29 through the exhaust blower 29. , those skilled in the art may appreciate that a bottom gas cleaning system according to the present invention may also be located according to other known location methods, on Reamer, by arranging in a row or by arranging a plurality of rows.

The dust cleaner 1 is a type of dust cleaner with a bag filter; the repair section of the dust cleaner 2 is located above the dust cleaner 1, the lifting means 3 is located on the upper part of the repair section of the dust cleaner 2, the waterproof canopy 4 is located above the side wall of the repair section of the dust cleaner 2, the maintenance platform of the dust cleaner 5 is located below the side wall of the repair section of the dust cleaner 2; a cyclic loading chute 6 is located between the lower part of the dust cleaner 1 and the reactor 9. A separation wall (not shown) can be provided on the ash bin section 30 below the dust cleaner 1, with an air inlet from the bottom mentioned in the previous text, for dispersing and averaging the gas flow, thus preventing a direct collision of the exhaust gas with the bottom of the bag filter, which may cause damage to the bag filter. An induced purge means (not shown) may be located at the top of the dust cleaner 1 with a gas inlet from the bottom to enhance the purge effect.

The reactor 9, used in conjunction with a dust cleaner 1, with a gas supply from the bottom as mentioned above, can be a multipoint reactor or a "located around the center" reactor, or a VRI reactor or a Venturi reactor. Reactor 9 differs from standard reactors used, as a rule, in a dry purification system, for purification of electrolysis exhaust gas, with respect to structural features and principles. When spraying, a standard reactor allows you to add alumina from the middle of the inlet pipe 8 of the dust cleaner to the pipe for mixing with electrolysis exhaust gas; The multipoint type reactor used in the present invention is in the form of a venturi pipe and adds alumina to the pipe through an overflow pipe, respectively, outside and from the middle of the gas supply pipe 8 of the dust cleaner, as a result of which the alumina particles are sufficiently mixed with the electrolysis exhaust gas in the pipe of a smaller diameter , increasing the efficiency of cleaning the electrolysis exhaust gas.

If the above standard reactor is used in conjunction with a dust cleaner 1 having a gas inlet from the bottom according to the present invention, this can save on investment and operating costs, but it can lead to disadvantages such as incomplete reaction and poor cleaning efficiency and may not meet the emission standards for environmental protection; if the multi-point reactor 9 according to the present invention is used in conjunction with a gas-sided dust cleaner according to the prior art, although the multi-point reactor shows increased efficiency, disadvantages such as damage to alumina, increased single-pass system resistance and increased investment due to too much a long section of the reaction tube. As can be seen above, the bottom gas purification system of the present invention is used in conjunction with a gas purifier 1 with a gas inlet from the bottom and a multipoint type reactor 9, which leads to the full manifestation of the characteristics of a multipoint type reactor, such as a high reaction efficiency and a longer reaction section.

The gas supply pipe of the dust cleaner 8 between the reactor 9 and the front collector of the dust cleaner 11 is provided with an inlet valve of the dust cleaner 10; the exhaust pipe of the dust cleaner 12 is provided with an outlet valve of the dust cleaner 13.

An impurity removal means 20 is provided between the alumina supply means 21 and the fresh alumina storage hopper 18, the alumina measuring means 22 is located below the alumina supply means 21; the alumina distribution means 23 communicates with the alumina supply means 21 through the fresh material chute 15.

The material lifting means 25 is connected to the material lifting means 26, and the material lifting means 26 is a Roots blower.

The bottom 1 of the dust cleaner, the alumina distribution means 23 and the return chute 14 are connected to one end of the ventilation pipe (as indicated by dashed lines above the ventilation means 27 shown in FIG. 2), and the other end of the ventilation pipe is connected to the ventilation means 27; the fresh material chute 15 is connected to one end of the ventilation pipe, and the other end of the ventilation pipe is connected to the ventilation means 27.

The electrolysis exhaust gas enters the electrolysis exhaust gas purification system through a gas trap hood of an electrolytic trap and an external outlet pipe of the workshop. Firstly, the electrolysis exhaust gas first enters the front collector of the dust cleaner 11, the gas supply pipe of the dust cleaner 8 being connected to the front collector of the dust cleaner 11, the gas supply pipes of the dust cleaner are arranged in parallel so that the reactor 9 and the dust cleaner 1 of the cleaning systems ensure stable use. The gas supply pipe of the dust cleaner 8 enters the dust cleaner 1 from the bottom, and the exhaust pipe of the dust cleaner 12 and the exhaust manifold of the dust cleaner 16 rest on the frame of the dust cleaner body. The fresh alumina feed system evenly distributes alumina for each of the following devices, for the purification system reactor through the fresh alumina storage hopper 18, for the impurity removal means 20, for the alumina feed means 21, for the alumina measuring means 22 and for the alumina distribution means 23. The returned alumina enters the return chute 14 through the inlet return pipe 7, and then the material is loaded into the hopper for the accumulation of fluorine-bearing alumina 19 through the material lifting means 25, and beyond em material enters the electrolysis plant for use in manufacturing. Fresh alumina and returned alumina are both provided with ventilation through a trough and dust cleaner ventilation means.

The purified exhaust gas leaving the dust cleaner passes through the blower 28 and is discharged into the atmosphere through the exhaust pipe 29.

Inspection and maintenance of the bag filter in the dust cleaner is carried out at the repair section of the dust cleaner 2, which can be outdoors or indoors. Inspection and maintenance of the dust cleaner is carried out using a lifting tool.

The outlet 13 valve of the dust cleaner and the inlet 10 valve of the dust cleaner remain closed during inspection and maintenance of the dust cleaner.

Compressed air from the pipeline network connected to the repair section of the dust cleaner 2 through the means of the pipeline for compressed air 24 is supplied to blow ash from the dust cleaner.

Claims (15)

1. System for dry cleaning of waste gas of electrolytic production of aluminum with a lower gas supply, comprising a dust cleaner, the bottom of which is connected to the front collector of the dust cleaner through the gas supply pipe of the dust cleaner, a multipoint type reactor located in the gas supply pipe of the dust cleaner, an alumina distribution medium located between the bulk reactor and fresh alumina hopper and distribution chute connected to said reactor, alumina feed means a, located between the alumina distribution means and the fresh alumina storage hopper, the fluorine-containing alumina storage hopper, the return chute, the means for lifting the material along the return chute, an output manifold, an exhaust pipe, a blower and an exhaust pipe, the upper part of the dust cleaner communicating with the exhaust collector through the exhaust collector the dust collector pipe and the dust collector output manifold are connected to the exhaust pipe through a blower, while below the dust cleaner there is provided a suction return pipe connected to an alumina lifting means through a return chute and to a storage hopper of fluorine-containing alumina. 2. The system according to p. 1, characterized in that the components of the system are located in one row or one after another, or in several rows. 3. The system according to claim 1, characterized in that the dust cleaner is made in the form of a dust cleaner with a bag filter. 4. The system according to claim 1, characterized in that a repair section of the dust cleaner is provided, located above the dust cleaner. 5. The system according to p. 4, characterized in that on the upper part of the repair section of the dust cleaner there is a lifting means. 6. The system according to claim 1, characterized in that on the ash bin section below the dust cleaner there is a dividing wall. 7. The system according to p. 1, characterized in that between the lower part of the dust cleaner and a multipoint reactor, a cyclic loading chute is provided. 8. The system according to claim 1, characterized in that the gas supply pipe of the dust cleaner is provided with an inlet valve of the dust cleaner located between the multi-point reactor and the front collector of the dust cleaner. 9. The system according to claim 1, characterized in that the exhaust pipe of the dust cleaner is equipped with an outlet valve for the dust cleaner. 10. The system according to p. 1, characterized in that between the means of feeding alumina and the storage hopper for fresh alumina placed a tool for removing impurities. 11. The system according to p. 10, characterized in that below the means of supplying alumina is a means of measuring alumina. 12. The system according to claim 1, characterized in that the alumina distribution means is communicated with the alumina supply means by means of a chute for fresh material. 13. The system according to p. 1, characterized in that the means of lifting the material is connected to a lifting means for venting the material. 14. The system according to claim 1, characterized in that the bottom of the dust cleaner, the alumina distribution means and the return chute are connected to one end of the ventilation pipe, and the other end of the ventilation pipe is connected to the ventilation means. 15. The system according to p. 12, characterized in that the chute for fresh material is connected to one end of the ventilation pipe, and the other end of the ventilation pipe is connected to the ventilation means.

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