RU2373467C1 - Drying agent recirculating device - Google Patents

Abstract

FIELD: heating systems, drying.

SUBSTANCE: invention refers to drying agent recirculating devices, and namely when drying exhausted beet pulp, and can be used in food, chemical and other industries. Drying agent recirculating device includes suction gas line from gas duct before the stack, ID-fan with control damper and delivery gas line to mixing chamber of furnace of the drying plant. According to invention, drying agent recirculating device is equipped with inertia-type turns with slot holes and with control dampers on the gas duct before the stack in order to collect wall boundary gas layers with increased dust content, and at ID-fan plant before cyclone, it is equipped, on exhaust pipe of cyclone, with volute with slot holes with control dampers for collecting wall boundary gas layer with increased dust content cyclone for cleaning extracted gas with increased dust content and product return to production, and ID-fan with suction and delivery gas lines with control dampers for supplying cleaned recirculating drying agent to furnace chamber along the circumference of internal surface of refractory lining and temperature decrease of flue gases up to temperature allowable for refractory and to mixing chamber of furnace in order to decrease drying agent temperature to product drying temperature required in drum.

EFFECT: invention must provide reduction of atmosphere pollution, heat flow and product losses.

3 dwg

Description

The invention relates to devices for recycling a drying agent, mainly when drying beet pulp, and can be used in food, chemical and other industries.

Drying plants are known in which recirculation of a drying agent is used, see "Drying in the chemical industry" MV Lykov. M.: Chemistry, 1970, p. 337, “Use of beet sugar production wastes” by TSINTIPISHEPROM. A.B. Fremel, M., - 1963, p. 19 ÷ 31; "Environmental Engineering." M .: Chemistry, 1981, p. 31 ÷ 39; "Production of dried beet pulp." V.D. Orlov, A.F. Zaborsin, S.L. Yarovoy. M .: "Light and food industry", 1983.

Closest to the invention by purpose and technical essence is a pulp dryer with recirculation of the used drying agent, see "Production of dried beet pulp", V.D. Orlov, A.F. Zaborsin, S.L. Yarovoy. M .: Light and food industry, 1983, p. 64, containing a firebox composed of a combustion chamber with a burner and a mixing chamber, a loading chamber, a drying drum, cyclones for cleaning the spent heat agent of drying, a smoke exhauster, a gas duct and a pipe, as well as a fan for air supply to the combustion chamber for combustion and cooling of the flue gases and a smoke exhauster for supplying the spent agent to the furnace mixing chamber.

The pulp dryer operates as follows.

Natural gas and air are supplied to the burner, as well as air is supplied along the inner contour of the lining to cool the flue gases to 1300 ° C.

Fan is supplied with air through the casing of the combustion chamber.

Then the flue gases pass into the mixing chamber, where they are cooled by the recirculating drying agent to the required temperature.

From the mixing chamber, flue gases cooled to the required temperature enter the drum.

The pressed pulp enters the dryer drum and by means of nozzles is evenly distributed over its cross section. The pulp is transported by the movement of gases and the presence of nozzles.

Hot flue gases move in the drum straight-through pulp and, in contact with it, quickly cool, while the moisture evaporates continuously and the pulp temperature does not rise above the boiling point of water at a steady pressure.

The exhaust gases with a temperature of 130 ÷ 140 ° C are sucked off and sent through a chimney exhaust through a chimney to a pipe or sucked off by a smoke exhaust and through a cyclone into a pipe.

A part of the spent drying agent is taken from the gas duct in front of the pipe with a separate gas duct using a smoke exhaust and sent to the furnace mixing chamber.

The existing device for recycling the drying agent has the following disadvantages:

- due to the use of deep press pulp presses, the effect of cleaning cyclones of 80-92%, the spent drying agent has a higher dust content and, accordingly, a higher pipe is needed and product loss, atmospheric pollution are observed;

- recirculation of the drying agent with a high dust content only through the mixing chamber of the furnace allows to save only 3 ÷ 5% of fuel;

- the increased dust content in the drying agent and entering it only through the mixing chamber of the furnace can cause foci of product ignition in the dryer drum.

The purpose of the invention is to reduce atmospheric pollution, reduce heat consumption, product losses.

This is achieved by the fact that the device for recirculating the drying agent, including a suction gas pipe from the gas duct in front of the pipe, a smoke exhauster with a regulating gate and a pressure gas pipe for introducing the drying furnace furnaces into the mixing chamber, according to the invention, is provided with inertial rotations with slot holes and with control gates for collecting wall layers of gas with a high dust content, and when installing a smoke exhaust in front of the cyclone, it is equipped with a snail with slotted holes on the exhaust pipe of the cyclone with control gates for collecting a wall layer of gas with a high dust content, a cyclone for cleaning the collected gas with a high dust content and returning the product to production, and a smoke exhauster with suction and discharge pipelines with control gates for introducing the cleaned recirculation drying agent into the combustion chamber by the periphery of the inner surface of the refractory lining and lowering the temperature of the flue gases to a temperature acceptable for refractories and into the mixing chamber of the furnace to reduce the temperature s drying agent to the desired product drying temperature in the drum.

Figure 1 schematically shows a device for recycling a drying agent in conjunction with an installation for drying beet pulp; figure 2 - place And figure 1, and when installing a smoke exhauster in front of the cyclone, see figure 3; figure 4; section AA.

Installation for drying beet pulp with a device for recirculating the drying agent has a combustion chamber 1, a mixing chamber 2, a loading chamber 3, a drum 4 for drying the pulp, an unloading chamber 5, a dry pulp auger 6, a cyclone 7 for cleaning the spent agent from dust with a shutter 8 , the exhaust fan 9, the pipe 10, and when installing the exhaust fan in front of the cyclone, the exhaust pipe 10A.

In the combustion chamber there is a casing 11, refractory masonry 12. At the front of the combustion chamber, a burner 13 is installed with a gas and air supply from the smoke exhauster 14.

At the front of the furnace there is an annular chamber 15 with channels 16 located on the periphery of the furnace chamber.

The device for recirculation of the drying agent when installing the exhaust fan after the cyclone is equipped with inertial turns 17 with slotted holes 18 and with regulating gates 19 on the gas duct in front of the pipe to collect wall layers of gas with a high dust content at the end of each rotation, and when installing the exhaust fan in front of the cyclone, the device is equipped with the exhaust pipe of the cyclone with a cochlea 17A with slotted holes 18 and with control gates 19 for collecting a wall layer of gas with a high dust content, a cyclone 20 with a lock gate 21 for cleaning and the collected gas with a high dust content and return the product in the production and exhaust fan 22 and 23 with the suction to the discharge gas lines 24, 25 with regulating dampers 26 and 27.

The operation of the device for recirculating the drying agent in the installation system for drying beet pulp is as follows.

The air through the casing 11 is heated and at the same time cools the housing of the combustion chamber 1, with a fan 14 it is supplied to the burner 13, to which fuel (gas) is also supplied. Combustion occurs in the combustion chamber, forming a torch. The temperature in the flare is about 1720 ° C with an excess air coefficient α = 1.25.

To reduce the temperature of the flue gases to an acceptable temperature for the refractory lining 12 (for example: up to 1000 ÷ 1300 ° C), the spent drying agent is fed into the annular chamber 15 and sent through channels 16 to the combustion chamber to cool the flue gases (for example, from 1720 to 1000 ÷ 1300 ° C).

Then the flue gases pass into the mixing chamber 2, where they are cooled by the recirculating drying agent to the required temperature. Next, the flue gases enter the loading device 3 and into the drum 4.

The pressed pulp enters the loading device 3 and then into the drum 4, in which drying by flue gases occurs. Dry pulp and flue gases enter the discharge chamber 5, in which dry pulp and spent drying agent are separated.

Dry pulp enters the auger 6 and then into production, and the spent drying agent enters the cyclone 7, where it is cleaned of dust (degree of purification 85-90%), and the captured dust is discharged through the shutter 8 into the auger 6.

The cleaned drying agent is sucked out of the cyclone 7 by the exhaust fan 9 and is pumped through the flue with inertial turns 17. The spent drying agent in inertial turns changes the flow direction. In this case, dust particles, trying to maintain the direction of movement after changing the direction of flow of the spent drying agent, are pressed against the walls and at the end of each rotation, wall layers of the spent drying agent with a high dust content through the slit holes are selected 18. The size of the wall layers of gas with a high dust content is regulated gate 19.

When installing a smoke exhauster before the cyclone, the spent drying agent is sucked out of the unloading chamber 5 of the smoke exhauster 9 and fed to the cyclone 7, where it is cleaned from dust by 85-90%, and the captured dust is discharged through the shutter 8 into the screw 6.

The purified drying agent in the cyclone rises through the exhaust pipe 10A, while continuing to rotate. In this case, the dust particles are pressed against the inner surface of the exhaust pipe 10A and through the slotted holes 18 with the help of regulating gates 19, a wall layer of the spent drying agent with a high dust content is removed through the cochlea 17A.

To recycle the drying agent of the exhaust fan 22 from all slots, part of the spent drying agent with an increased dust content of up to 40% of the total amount of drying agent exhausted is sucked out and through the gas duct 23, cyclone 20 and is pumped through the gas duct 24 with the control gate 26 into the annular chamber 15 and through the channels 16 is fed into the combustion chamber 1 in the required amount to reduce the temperature of the flue gases to, for example, 1100 ± 100 ° C.

In addition, the recirculation drying agent is pumped through the gas duct 25 with the gate 27 to the mixing chamber 2 in the required amount to reduce the temperature of the flue gases to a temperature for drying the product in the drum.

The recirculation of the drying agent is carried out in automatic mode, depending on the required temperature of the flue gases in the combustion chamber and the mixing chamber of the furnace of the installation for drying the pulp.

In cyclone 20, the recirculating drying agent is cleaned of product dust and the captured product dust is returned to production through shutter 21 and screw 6.

The dust-free part of the spent drying agent is sent to the pipe 10.

Moreover, the amount of emissions decreases with a lower dust content. This reduces atmospheric pollution.

The proposed device for recycling the drying agent will allow:

- reduce heat consumption for drying the product up to 10 ÷ 12%;

- increase the humidity of the drying medium, avoid local overheating of the material, increase the speed of the drying agent;

- reduce the amount of dust emissions of the product into the atmosphere by about 2 times;

- return of the product to production up to about 0.3%.

Claims (1)

A device for recirculating a drying agent, including a suction gas pipe from the gas duct in front of the pipe, a smoke exhauster with a regulating gate and a discharge gas pipe for introducing the drying furnace furnaces into the mixing chamber, characterized in that it is provided with inertial rotations with slotted openings and with regulating valves for the gas duct in front of the pipe collecting wall layers of gas with a high dust content, and when installing a smoke exhauster in front of the cyclone, it is equipped on the exhaust pipe of the cyclone with a snail with slotted holes with regulating beers for collecting a wall layer of gas with a high dust content, a cyclone for cleaning the collected gas with a high dust content and returning the product to production, and a smoke exhauster with suction and discharge gas pipelines with control gates for introducing a cleaned recirculation drying agent into the combustion chamber along the periphery of the inner surface refractory lining and reducing the temperature of the flue gases to a temperature acceptable for refractories, and into the mixing chamber of the furnace to reduce the temperature of the drying agent to ne sary product drying temperature in the drum.

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