RU2531313C1 - Method of gas treatment from dust - Google Patents

Abstract

FIELD: power engineering.

SUBSTANCE: method of gas treatment from dust includes introduction of cleaned gas into a cyclone with an upper axial exhaust nozzle, gas treatment from dust due to action of centrifugal forces under reciprocal motion of a rotary flow in a bottom-up direction in a cylindrical body with turning of cleaned flow upwards. After that they collect the flow of trapped dust in a dust collector, an auxiliary coagulating liquid flow is supplied into the cyclone, being aligned to a flow of trapped dust, to form a mixture of trapped dust and liquid, briquetting of the mixture on a roller press, installed in the lower part of the dust collector, with formation of a flow of briquettes in an above-hopper space and loading of briquettes into a collecting hopper. At the same time during gas treatment with reciprocal motion of the rotary flow in a top-down direction in the cyclone cylindrical body it is cooled with the help of a heat exchanger generating water vapour, then the latter is supplied into the above-hopper space in the form of water vapour jets oriented at the flow of briquettes.

EFFECT: increased extent of gas treatment from dust and expanded process capabilities of the method for gas treatment from dust.

1 tbl, 1 dwg

Description

The invention relates to a technology for cleaning gases from dust in the power system, ferrous and non-ferrous metallurgy.

There is a method of cleaning gases from dust, which consists in the tangential supply of dusty gas, cleaning gas from dust 'due to the action of centrifugal forces, separating dust from gas in the sweep zone of the purified gas, collecting dust flows in a dust collector (see Dust collection in metallurgy. Reference / V.M. Aleshina, A.Yu. Waldberg, G.M. Gordon and others, M .: Metallurgy, 1984, p. 48-52). The disadvantage of this method of cleaning gases from dust is the low efficiency of the dust collection process.

The closest in technical essence and the achieved result is a method of cleaning gases from dust, including introducing a gas to be cleaned into a cyclone with an upper axial exhaust pipe, cleaning gas from dust due to the action of centrifugal forces during translational movement of a rotating stream from top to bottom with a turn of the cleaned stream up, collection the stream of trapped dust in the dust collector, the supply of auxiliary coagulating liquid to the cyclone, oriented to the stream of trapped dust with the formation of a mixture of trapped dust and liquid, briquettes mixing the mixture on a roller press installed in the lower part of the dust collector with the formation of a briquette stream in the above-hopper space, loading the briquettes into the collection hopper (see Patent No. 2392059, Russia, IPC 8 B04C 5/18, filed September 24, 2009, published June 20, 2009 Bull. No. 17).

A disadvantage of the known technical solution is the low efficiency of gas cleaning from dust due to the high temperature of the gas to be purified, which increases the viscosity of the gas and impedes the action of centrifugal forces during the translational movement of the gas, which ultimately reduces the efficiency of dust collection. At the same time, in the process of gas purification in the dust collector and in the above-hopper space of the dust collector, a low temperature of gases is formed, which does not allow to efficiently organize the drying process of briquettes and their necessary hardening. Therefore, insufficiently strong briquettes at a low temperature of the bunker space are partially destroyed and form secondary dust formation, which reduces the efficiency of dust collection. To eliminate these drawbacks during the progressive movement of gases in a cylindrical cyclone body, it is necessary to organize a rational temperature regime of dust collection, and in the dust collector and in the above-hopper space, an optimal thermal regime of dust briquetting should be formed, for which the gases to be cleaned must be cooled, and part of the thermal energy from the cyclone's working space should be transfer to the super-bunker space, where briquettes should be dried.

The objective of the invention is to increase the degree of purification of gases from dust and the expansion of technological capabilities of a method for purifying gases from dust.

The problem is achieved in a method for cleaning gases from dust, including introducing a gas to be cleaned into a cyclone with an upper axial exhaust pipe, cleaning gas from dust due to the action of centrifugal forces during translational movement of a rotating stream from top to bottom in a cylindrical body with a turn of the purified stream upward, collecting the flow caught dust in the dust collector, feeding into the cyclone stream of auxiliary coagulating liquid oriented to the stream of trapped dust with the formation of a mixture of trapped dust and liquid, briquetting the mixture and on a roller press installed in the lower part of the dust collector, with the formation of a briquette stream in the above-hopper space, loading the briquettes into the collecting hopper, and during gas purification during the translational movement of the rotating flow from top to bottom in a cylindrical cyclone body, it is cooled using a heat exchanger generating steam , then the latter is fed into the super-bunker space in the form of jets of water vapor oriented to the briquette stream.

The invention consists in the following. To cool the gases in the working space of the dust collector and reduce their temperature, a water heat exchanger is installed in the cylindrical body, which generates water vapor of certain parameters. Installing a water heat exchanger has two tasks: cooling the purified gases and lowering their temperature by utilizing their thermal energy with water and steam and transferring this energy with water vapor to the super-bunker space, which is necessary to increase the temperature in the dust collector and in the super-bunker space to drying temperatures and drying the flow of briquettes in the bunker space.

Cooling the cleaned gases and lowering their temperature using a heat exchanger under the action of centrifugal forces and the translational motion of a rotating stream reduces the viscosity of the gases, which allows to increase the efficiency of dust collection by 5-10%. The supply of water vapor with a temperature of 100-110 ° C into the super-bunker space in the form of steam jets oriented to the briquette stream allows for complete drying of the briquettes and their necessary hardening due to the formation of a strong coagulation structure, which reduces secondary dust generation during dust briquetting.

The supply of water vapor in the super-bunker space at the same time allows to increase the temperature of the briquette press rollers to 80-90 ° C, which also intensifies the drying of briquettes and facilitates their cleaning from the surface of the rollers without destroying the briquettes. As a result, there is no formation of dust during its briquetting and during transportation of briquettes from the above-hopper space to the collecting hopper, which reduces the secondary dusting of the cleaned stream.

The use of water heat exchangers and water vapor is widely known in the art (see Metallurgical heat engineering. Volume 2 / V.A. Krivandin et al. - M .: Metallurgy, 1986, p. 192). However, the integrated use of a water heat exchanger and water vapor for organizing an optimal temperature regime for cleaning gases from dust and a rational thermal regime for dust briquetting is proposed for the first time in the present invention. If necessary, in the proposed method of gas purification, partial selection of water vapor from the dust collection system for technological needs and heating is possible, which further extends the technological capabilities of the proposed method.

Thus, due to the distinguishing features, the claimed method acquires new properties: organized cooling of the cleaned gases under the action of centrifugal forces and the translational movement of the rotating flow from top to bottom, combined with heat recovery and dust collection; regulated utilization of heat of the gas to be purified with the generation of water vapor used for organizing the thermal drying of briquettes in a single dust collector; volumetric heat absorption of the flow of freely falling briquettes due to the oncoming supply of jets of water vapor; effective hardening of dried briquettes in the absence of dust formation in the super-bin space of the dust collector. These properties increase the efficiency of dust collection and expand the technological capabilities of the method of cleaning gases from dust. Thus, we believe that the invention meets the criteria of novelty, inventive step and industrial applicability.

The gas purification method is implemented using the device shown in the figure. It contains a supply pipe 1, a housing 2, an exhaust pipe 3, a dust collector 4, a pipe 5 for supplying coagulating liquid, a roller press 6, a collecting hopper 7, a hopper space 8, a water heat exchanger 9 with a supply pipe, a steam pipe 10, an annular steam jet device 11. In the process, in the dust collector jets of coagulating liquid 12 are formed, streams of trapped dust 13, briquettes 14, jets of water vapor 15.

The method of gas purification is as follows. The dusty gas stream through the pipe 1 enters the housing 2, where the gases are cleaned from dust due to the action of centrifugal forces during the forward movement of the rotating stream from top to bottom. A coagulating liquid, for example, a solution of liquid glass or sulphite-yeast mash (SDB), oriented in the form of jets 12 to a dust collector 4, is supplied through a pipeline 5. The cleaned gas stream enters the environment through the exhaust pipe 3. In the process of gas cleaning from dust, the gas to be purified gives off heat heat receiver (water and water vapor) of the water heat exchanger 9 and is cooled to the required temperature. Steam is generated in the heat exchanger 9, which is supplied through the steam line 10 to the annular steam jet device 11. The steam nozzle 11 has steam nozzles oriented to the super-hopper space 8 and forming jets of water vapor 15. The streams of trapped dust 13 enter the dust collector 4 and move into the form of a mixture of dust and coagulating liquid in its lower part. The mixture of dust and liquid enters the loading unit of the roller press 6. After briquetting a wet mixture of dust and liquid, briquettes 14 are formed, which in the form of a free-flowing stream enter the super-bunker space 8, pass through the jets 15 of hot water vapor, are dried and then enter the collecting hopper 7. Waste water vapor passes through the slit space formed by the rollers of the press and is removed through the exhaust pipe 3 into the atmosphere.

Example. The development of a method for cleaning gases from dust was carried out on a centrifugal dust collector with a diameter of 300 mm, equipped with a water heat exchanger, a steam pipe, an annular steam-jet device, a coagulating fluid supply system and a roller press, according to the technical diagram. The dust collector was installed on the chimney of a laboratory boiler unit operating on the coal corner of the Yerunakovsky mine with a flow rate of 20 kg / h. The temperature of the exhaust flue gases dusted with ash and slag particles 0-0.1 mm in size was 350-400 ° C. Sulphite yeast mash (SDB) was used as a coagulating liquid. The flow rate of the coagulating fluid was 6 g / s. The water flow in the water heat exchanger was varied from 20 g / s to 100 g / s. The dust collection efficiency was determined by the external filtration method. The obtained briquettes were determined by compressive strength. The experimental results are presented in the table.

Table The performance of the method of cleaning gases from dust Water consumption in the heat exchanger, g / s Dust collection efficiency,% The strength of briquettes, kPa one twenty 79.8 310 2 60 80.5 350 3 one hundred 82.9 420 Prototype Data four - 78,4 300

Experimental data show that the proposed method for cleaning gases from dust has a higher efficiency (1.4-4.5%) compared with the prototype and allows to obtain ash and slag briquettes based on SDB with a strength of 310-420 kPa.

Claims (1)

A method for cleaning gases from dust, including introducing gas to be cleaned into a cyclone with an upper axial exhaust pipe, cleaning gas from dust due to the action of centrifugal forces during translational movement of a rotating stream from top to bottom in a cylindrical body with a turn of the cleaned stream up, collecting a stream of trapped dust in a dust collector, supply to the cyclone stream of auxiliary coagulating liquid, oriented to the stream of captured dust, with the formation of a mixture of captured dust and liquid, briquetting the mixture on a roller press, installed m in the lower part of the dust collector, with the formation of a briquette stream in the above-hopper space, loading the briquettes into a collection hopper, characterized in that it is cooled with the help of a heat exchanger generating water vapor during the progressive movement of the rotating stream from top to bottom in the cylindrical cyclone body, then the latter is fed into the super-bunker space in the form of jets of water vapor oriented to the flow of briquettes.