RU2779452C1 - Method for gas cleaning from dust - Google Patents

Abstract

FIELD: gases cleaning.

SUBSTANCE: invention relates to a technology for cleaning gases from dust in thermal power engineering, ferrous and non-ferrous metallurgy. The method for cleaning gases from dust includes introducing gas to be cleaned from dust into a cyclone through an inlet pipe, cleaning gas from dust in a cylindrical housing due to the action of centrifugal forces during the translational movement of a rotating flow from top to bottom with a turn of the cleaned flow upwards through the upper axial exhaust pipe, collecting the flow of trapped dust, spraying auxiliary coagulating liquid in the form of jets oriented to the flow of trapped dust. Before moistened sawdust is supplied to the cyclone, a part of sawdust in the amount of 1-20% is separated from the main flow and additionally added to the auxiliary coagulating liquid, forming a solid-liquid flow, which is then sent to the cyclone inlet in the form of jets and irrigate the gas to be purified with it. The resulting sludge is sent to the sludge collector, from where it is transported by means of a screw conveyor to the loading unit of the roller press. In this case, the sludge is partially dehydrated and thickened, and the separated part of the auxiliary coagulating liquid is directed to form a solid-liquid flow.

EFFECT: invention provides increased efficiency of gas purification from dust and increased stability of briquetting; wherein the claimed method allows you to pre-purify the gas even at its inlet to the dust collector, and the partial dehydration of the sludge, which has low humidity and high viscosity, can stabilize the briquetting process.

1 cl, 1 dwg, 1 tbl

Description

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

A known method of cleaning gases from dust, which consists in a tangential supply of dusty gas, cleaning gas from dust due to the action of centrifugal forces, separating dust from gas in the zone of the cleaned gas reversal (see Dust collection in metallurgy. Reference book / V.M. Aleshina, A. Yu. Waldberg, G. M. Gordon et al., Moscow: Metallurgy, 1984, pp. 48-52).

The disadvantage of the known method of gas purification is the low efficiency of the dust collection process.

The closest in technical essence and the achieved result is a method for cleaning gases from dust, including entering the gas to be cleaned into a cyclone with an upper axial exhaust pipe, cleaning the gas from dust in a cylindrical housing due to the action of centrifugal forces during the translational motion of a rotating flow from top to bottom with a turn of the cleaned flow upward, collecting the flow of trapped dust, spraying the auxiliary coagulating liquid in the form of jets oriented to the flow of captured dust, with the formation of a mixture of trapped dust and auxiliary coagulating liquid, briquetting the mixture of trapped dust and auxiliary coagulating liquid on a roller press, and briquetting the mixture of trapped dust and auxiliary coagulating liquid is carried out together with sawdust, pre-moistened with an auxiliary coagulating liquid to a moisture content of 1-15%, which is fed into the upper part of the cyclone body, and the roller press is located in the lower part of the cyclone body womb. (RU No. 2567310, IPC B04C 5/00, B04D 47/00, published on November 10, 2015).

The disadvantage of the known method of cleaning gases from dust is the low efficiency of gas cleaning due to the difficulty of placing the irrigation system in the cyclone body and the lack of an irrigation system in the inlet pipe of the dust collector. In this case, there is a violation of the stability of briquetting due to high humidity and low viscosity of the briquetting mixture. It is possible to lower the humidity and increase the viscosity of the mixture being briquetted by reducing the consumption of the coagulating liquid, but this will reduce the efficiency of gas purification from dust, which contradicts the technology of gas purification from dust and reduces the yield of conditioned briquettes.

The technical problem solved by the present invention is to increase the efficiency of dust removal from gases and increase the stability of briquetting.

The technical problem is solved by the fact that in the known method of cleaning gases from dust, which includes introducing the gas to be cleaned through the inlet pipe into the cyclone, cleaning the gas from dust in a cylindrical housing due to the action of centrifugal forces during the translational movement of the rotating flow from top to bottom with the turn of the purified flow upward through the top axial exhaust pipe, collection of the trapped dust flow, spraying of the auxiliary coagulating liquid in the form of jets oriented to the flow of captured dust, supply of sawdust moistened with the auxiliary coagulating liquid to the upper part of the cyclone body, formation of a mixture of trapped dust, sawdust and auxiliary coagulating liquid, briquetting a mixture of trapped dust, sawdust and an auxiliary coagulating liquid on a roller press, according to the invention, before being fed into the cyclone, a part of the sawdust in the amount of 1-20% is separated from the main flow and additionally added to the auxiliary coagulating liquid, forming a solid-liquid flow, which is then sent to the inlet pipe of the cyclone in the form of jets and the gas being cleaned is sprayed with it, and the resulting sludge is sent to the sludge collector, from where it is transported by means of a screw conveyor to the loading unit of the roller press, while the sludge is partially dehydrated and thickened , and the separated part of the auxiliary coagulating liquid is directed to form a solid-liquid flow.

The technical result when using the invention is as follows. To improve the efficiency of dust collection and the stability of briquetting, in the method of cleaning gases from dust, it is proposed to separate a part of sawdust in the amount of 1-20% from the main flow before feeding into the cyclone and additionally add them to the auxiliary coagulating liquid to obtain a solid-liquid flow. After that, the solid-liquid flow in the form of a mobile liquid containing sawdust and capable of spraying is fed into the inlet pipe of the cyclone in the form of jets and irrigates the purified gas with it, carrying out preliminary purification of the gas even at its inlet to the dust collector. In the process of preliminary purification of gases, sludge is formed in the inlet pipe, which is thickened and partially dehydrated from the excess of auxiliary coagulating liquid using a screw conveyor and transported to the loading unit of the roller press by the same conveyor. Partially dehydrated sludge has low moisture content and high viscosity, which can stabilize the briquetting process. The auxiliary coagulating liquid mechanically separated from the sludge is again sent to the system to form a solid-liquid flow for re-participation in the dust collection process. In the process of loading the dehydrated sludge into the roller press, it is mixed with a wetter mixture formed in the cyclone from dust, sawdust and auxiliary coagulating liquid, and forms a briquetting mass of the required moisture and viscosity, which increases the stability of briquetting.

The method of cleaning gases from dust is effectively carried out if, before being fed into the cyclone, the amount of sawdust separated from the main flow, additionally added to the auxiliary coagulating liquid, will be 1-20%. If the amount of sawdust separated from the main flow, additionally added to the auxiliary coagulating liquid, is less than 1%, then the content of sawdust will be minimal and they will not participate in the process of cleaning gases from dust, and the efficiency of the method of cleaning gases from dust will be low. If the amount of sawdust separated from the main stream, additionally added to the auxiliary coagulating liquid, is more than 20%, then the viscosity of the solid-liquid stream will be increased and it will be difficult to spray such a stream mechanically, which will reduce the efficiency of the method for cleaning gases from dust and contradicts the objective of the invention. In this case, the transportation of excessively viscous sludge will also be difficult, which will reduce the stability of briquetting.

The method of cleaning gases from dust is implemented using a cyclone shown in the drawing.

The cyclone contains an inlet pipe 1, a cylindrical body 2, an exhaust pipe 3, a dust collector 4, a pipeline 5 for supplying an auxiliary coagulating liquid, a roller press 6. The device is equipped with a hopper 7 for moistening sawdust. To moisten the sawdust in the hopper 7 with an auxiliary coagulating liquid, nozzles 8 are provided. For the dosed supply of sawdust to the cyclone body, an aerator 9 is installed in the lower part of the hopper 7, along the axis of which a nozzle 10 is fixed for supplying compressed air. To form a solid-liquid flow containing 1-20% wood sawdust, an additional hopper 11 was built. An intake device 12 was installed to collect moistened sawdust from hopper 7. A pipeline 13 was installed to supply auxiliary coagulating liquid to hopper I. A pipeline 13 was installed to transport the solid-liquid flow to the inlet pipe 1 cyclone, a pipeline 14 and a pump 15 are installed. To irrigate the gas to be purified with a solid-liquid flow, nozzles 16 are installed in the inlet pipe 1. To collect sludge, a sludge collector 17 is installed in the lower part of the inlet pipe. screw conveyor 19. The screw conveyor 19 partially dehydrates and thickens the sludge, transporting it to the loading unit of the roller press 6. A drainage channel 20 is built to transport the separated auxiliary coagulating liquid. During the operation of the device, a loaded main stream is formed sawdust 21, the selected stream of moistened sawdust 22, jets 23 of auxiliary coagulating liquid, a mixture of trapped dust, auxiliary coagulating liquid and sawdust 24, briquettes 25. shut-off valve 26 serves.

The method of purification of gases from dust is carried out as follows. Initially, the main flow of sawdust 21 is fed into the hopper 7 for moistening. Moistening of sawdust is carried out with an auxiliary coagulating liquid taken from the pipeline 5 through a separate path using nozzles 8. The flow rate of the liquid is regulated by shut-off valves 26. The metered supply of moistened sawdust into the cyclone body from the bottom of the hopper 7 is carried out using an aerator 9, on the axis of which is installed nozzle 10 for supplying compressed air. The flow of gas to be purified is tangentially fed through the inlet pipe 1 into the cylindrical body 2 of the cyclone. An irrigation system is installed in the inlet pipe in the form of a set of nozzles 16, which spray the solid-liquid flow formed in the additional hopper 11. To form a solid-liquid flow, a stream of moistened sawdust 22 is fed into the hopper 11, taken from the hopper 7 using the intake device 12, then into the hopper 11 an auxiliary coagulating liquid is supplied through pipeline 13, the flow rate of which is controlled by shut-off valves 26. The formed solid-liquid flow from the hopper 11 is fed to the inlet pipe 1 through the pipeline 14 using a pump 15. After preliminary cleaning of the gases in the inlet pipe 1, sludge is formed, which enters the sludge collector 17 The sludge is transported to the loading unit of the roller press 6 through the sludge pipeline 18 using a screw conveyor 19. The screw conveyor 19 partially dehydrates and thickens the sludge, separating part of the auxiliary coagulating liquid from solid particles. Transportation of the separated auxiliary coagulating liquid to the hopper 11 is carried out through the drainage channel 20 using a pump. Partially dehydrated and thickened sludge enters the loading unit of the roller press 6. From the inlet pipe 1, the gas to be purified enters the body 2 of the cyclone. Due to the action of centrifugal forces, the gas performs a forward rotational motion from top to bottom, during which, due to inertial coagulation, the dust is captured by moistened sawdust supplied through the aerator 9. Moistened sawdust, saturated with dust, enters the irrigation zone of jets 23 of the auxiliary coagulating liquid, taken from pipeline 5 along a separate path. The resulting mixture of trapped dust, liquid and sawdust 24 enters the rotating working surfaces of the roller press 6. Then the mixture 24 is transported to the press loading unit 6, where it mixes with the sludge coming from the sludge collector 17 using a screw conveyor 19. A mixture of trapped dust, liquid and sawdust is mixed with sludge and forms a briquetting mass of the required moisture and viscosity, which allows stabilizing the briquetting process. After briquetting the mass, briquettes 25 are obtained, which enter the dust collector 4, which acts as a briquette accumulator, and then are sent for recycling to consumers. If necessary, the press rollers are cleaned with a cleaner (not shown in the diagram) of any known design used in the industry. The purified gas flow exits to the environment through the exhaust pipe 3.

Example. Testing of the method of cleaning gases from dust was carried out on a laboratory centrifugal dust collector with a diameter of 300 mm, manufactured according to the above technical scheme. It was equipped with an auxiliary coagulating fluid supply system, a hopper for sawdust, nozzles for moistening them, an aerator designed to supply sawdust to the upper part of the cyclone body, and a roller press located in the lower part of the cyclone body. To form a solid-liquid flow containing sawdust, an additional hopper was built, which was connected by a pipeline to nozzles installed in the inlet pipe body. Sawdust was taken from the sawing machines of the Novokuznetsk DOK, equipped with circular saws. Sulfite yeast mash (SDB) was used as an auxiliary coagulating liquid. The inlet gas flow from the fan was dusted with ash and slag particles 0-0.1 mm in size. The cylindrical aerator had a diameter of 100 mm and a length of 200 mm. Compressed air was supplied to the aerator at a pressure of 0.2 MPa through a 10 mm nozzle. In the work, we changed the amount of sawdust separated from the main sawdust flow and additionally added to the auxiliary coagulating liquid to form a solid-liquid flow. The flow rate of the auxiliary coagulating liquid was regulated by shutoff valves. The efficiency of dust collection was determined by the method of external filtration. The stability of briquetting was determined by the mass yield of conditioned briquettes with a size of 15×15 mm and by the value of their compressive strength. The results of the experiments are presented in the table.

As can be seen from the above data, the proposed method of cleaning gases from dust allows to increase the efficiency of cleaning gases from dust by 3.0-6.8% (abs.) and the stability of briquetting by increasing the yield of conditioned briquettes by 0.8-4.6 % (abs.).

Claims (1)

A method for cleaning gases from dust, including introducing the cleaned gas into the cyclone through the inlet pipe, cleaning the gas from dust in a cylindrical housing due to the action of centrifugal forces during the translational movement of the rotating flow from top to bottom with the turn of the cleaned flow upward through the upper axial exhaust pipe, collecting the flow of trapped dust , spraying auxiliary coagulating liquid in the form of jets oriented to the flow of trapped dust, supplying sawdust moistened with auxiliary coagulating liquid to the upper part of the cyclone body, forming a mixture of trapped dust, sawdust and auxiliary coagulating liquid, briquetting a mixture of trapped dust, sawdust and auxiliary coagulating liquid on a roller press, characterized in that before being fed into the cyclone, a part of sawdust in the amount of 1-20% is separated from the main flow and additionally added to the auxiliary coagulating liquid, forming a solid-liquid flow, which then it is sent to the inlet pipe of the cyclone in the form of jets and the gas being cleaned is sprayed with it, and the resulting sludge is sent to the sludge collector, from where it is transported by means of a screw conveyor to the loading unit of the roller press, while the sludge is partially dehydrated and thickened, and the separated part of the auxiliary coagulating liquid is sent to form a solid-liquid flow.

Images