RU2499211C1 - Timber condensation drier with absorption utiliser - Google Patents

Abstract

FIELD: heating.

SUBSTANCE: drier includes an absorption lithium bromide heat pump - utiliser, a drying air circulation and conditioning system and a drying chamber housing. The drying chamber housing is made in the form of a heat-and-steam insulated room with an arched ceiling and a false ceiling. The drier structure differs from the fact that the drying air circulation and conditioning system is located above the false ceiling. The drying air circulation and conditioning system consists of reversible fans and recuperative heat exchangers of water-air type. Heat exchangers are located on both sides of the fans; those of them, which are located on the suction side, are driers. The heat exchangers that are located on the discharge side, are heaters. Driers and heaters exchange their roles at variation of air circulation direction. In order to obtain cold and hot water supplied to heat exchangers, an absorption lithium bromide heat pump is used.

EFFECT: reduction of heat and electric energy costs during the drying process of timbers; improvement of efficiency and provision of high-quality dried timber.

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Description

The invention relates to drying equipment and can be used for drying lumber.

From the existing level of technology there is a known installation for drying lumber, containing a thermally insulated airtight casing, divided by a partition onto a drying chamber of a stack of lumber with air ducts formed in it, sensors placed therein to control temperature and humidity, and to a hardware unit including a control system for the operation of the installation connected with the indicated sensors, heating devices of the agent, transported by fans installed in the upper part of the partition, into the drying chamber, condensation minutes with the fan drive and a condensing device with a closed cooling circuit and tray for collecting condensate (Patent RU 44802 U1, publ. 27.03.2005).

The disadvantages of this technical solution are: the use of a compression heat pump leads to increased energy consumption and allows drying only at low temperature, the interaction of the interior of the dryer with atmospheric air through the ventilation windows leads to large heat losses.

Closest to the claimed technical solution is an economical drying chamber containing a heat-insulated casing with lockable end openings for loading and unloading material and a longitudinal vertical diaphragm, as well as a fan unit with an integrated air humidifier (Patent RU 2338136 C1, publ. 10.11.2008). This dryer uses a closed circuit to circulate the drying agent without interacting with atmospheric air, which reduces losses.

The disadvantages of this technical solution are: use as a conditioning unit of a compression heat pump, which consumes a large amount of electrical energy; the use of additional devices for heating the drying agent leads to a rise in cost of the installation and a decrease in its energy efficiency. In addition, the proposed dryer has a low productivity.

The technical result of the invention is to reduce the cost of heat and electric energy in the drying process of wood lumber, increase the productivity of condensation drying chambers, drying lumber at normal temperature conditions in accordance with GOST 19773-84 "Softwood and hardwood lumber. Drying modes in batch chambers ”, improving the quality of dried lumber.

The specified technical result is achieved by the fact that the claimed condensation dryer for lumber with an absorption utilizer, including a drying chamber made in the form of a heat-insulated room with a false ceiling, a circulation and conditioning system for drying air, a heat pump; contains lithium bromide absorption heat pump - a heat recovery unit used to produce hot and cold water supplied to heat exchangers; drying air circulation and conditioning system located above the false ceiling and consisting of reversible fans and water-air recuperative heat exchangers located on both sides of the fans on the suction and discharge sides, performing the functions of dehumidifiers and air heaters, respectively, while changing their functions when reversing the air flow; a system for supplying heat carrier (water) to recuperative heat exchangers, made in such a way that hot water enters heat exchangers located on the discharge side of the fans, and cold water enters heat exchangers located on the suction side of the fans, and when the air stream is reversed, flows of cold and hot water change the direction of their movement.

The condensation dryer for lumber with an absorption heat exchanger is equipped with recuperative heat exchangers having condensate collectors and steam traps.

Condensing dryer for lumber with an absorption heat exchanger is equipped with an absorption heat pump located outside the drying chamber and is the main source of heat and cold necessary for drying lumber.

The novelty lies in the fact that the main source of useful heat and cold necessary for the operation of a condensation dryer is a lithium bromide absorption heat pump; the condensation drying chamber is equipped with a raised ceiling, over which reversible fans and recuperative water-air heat exchangers are placed; the connection diagram of the heat pump and heat exchangers is designed in such a way that allows you to automatically change the functions of the heaters and dehumidifiers among themselves.

The invention is illustrated by drawings, which depict:

figure 1 - diagram of the device of a condensation dryer for lumber with an absorption utilizer;

figure 2 - diagram of the circulation of coolants between the heat exchanger and recuperative heat exchangers.

A condensation dryer for lumber with an absorption heat exchanger (Fig. 1) contains an absorption lithium bromide heat pump 1, a heat-insulated dryer body with a vaulted ceiling 2, false ceiling 3, above which there are reversible fans 4 and regenerative heat exchangers 5 and 6. Under all recuperative heat exchangers are condensate trays 7, which are connected by a steam trap 8. A stack of drained lumber 9 is loaded into the drying chamber.

The device operates as follows: drained lumber 9 is loaded into the dryer in the form of a stack having spatial gaps for the necessary air circulation between the layers of lumber (you need to describe the operation of the device if the device is claimed). The fans 4 are included in the operation, while the drying agent (air) begins to circulate in the enclosed space of the dryer. Then, the lithium-bromide absorption heat pump 1 is started, while hot water 10 starts to circulate through the recuperative heat exchangers 5 - heaters located on the discharge side of the fans 4. And cold water starts to flow through the regenerative heat exchangers 6 - dehumidifiers located on the intake side of the fans 4. water 11. Hot water and cold water acquire the required temperature using a heat pump.

The air in the dryer circulates in a closed loop. Fans 4 direct the flow of dried air 12 through heaters 5, from which it is heated to the drying temperature and sent to a stack of lumber 9 on one side. Hot and dry air 13 passes through a loose stack and heats the lumber. Moisture evaporating from the surface of the wood moistens the drying air, while its temperature decreases. Wet and warm air 14 is drawn by the fan into the gap between the false ceiling 3 and the dryer body 2 on the opposite side of the stack and passes through dehumidifiers 6, in which it is cooled to the saturation temperature. As a result, part of the moisture condenses on the surfaces of the dehumidifiers and flows into the condensate collectors 7, from which it is gravity removed outside the drying chamber by the steam trap 8. The air acquires the necessary moisture content and is again directed by the fan to the heaters, and the cycle repeats.

The technology of high-quality drying of wood by a convective method involves reversing the flow of a drying agent through a stack of lumber. The design of the proposed condensation dryer allows drying with reversal of the flow of drying air. This is achieved through the use of reversible fans, recuperative heat exchangers located on both sides of the fans, and a certain pattern of circulation of coolants between the heat exchanger and heat exchangers (figure 2). The circulation scheme of the heat carriers works as follows: in the initial direction of movement of the drying air, hot water 10 from the heat exchanger enters the heaters 5, of which already somewhat cooled hot water 15 enters the heat exchanger for heating; and cold water 11 from the heat exchanger enters the dehumidifiers 6, from which the somewhat warmed cold water 16 returns back to the heat exchanger for cooling. When the direction of movement of the drying air is reversed, certain electromagnetic valves 20 are automatically opened and closed, after which the hot water enters the heat exchangers 6 , which were previously dehumidifiers, and cold - to heat exchangers 5, which were previously heaters. That is, heaters and dehumidifiers change roles.

The operation of the lithium-bromide absorption heat pump 1 requires high potential heat, which can be obtained by burning wood waste 18 in the heat pump generator 17, such as sawdust, wood chips, wood shavings, etc. The heat of combustion of wood waste is transferred to the lithium bromide solution through the wall separating them by radiation in the furnace of this generator and convective heat transfer in the duct of the same generator 17. The flue gases 19 can be cleaned by cooling below the dew point. Exhaust flue gas is cooled by an additional condensing heat exchanger installed in the convection duct after the generator. Cold water circulated inside the condensation heat exchanger obtained in the evaporator of the absorption heat pump; for this, an additional heat exchanger is installed in the evaporator. In this case, the heat released during cooling of the flue gas is an additional source of low-grade heat for the absorption heat pump.

Claims (1)

A condensation dryer for lumber with an absorption utilizer, including a drying chamber made in the form of a heat-insulated room, a circulation and conditioning system for drying air, a heat pump, characterized in that it contains a lithium-bromide absorption heat recovery utilizer used to produce hot and cold water, fed to heat exchangers; drying air circulation and conditioning system located above the false ceiling and consisting of reversible fans and water-air recuperative heat exchangers located on both sides of the fans on the suction and discharge sides, performing the functions of dehumidifiers and air heaters, respectively, while changing their functions when reversing the air flow; a system for supplying heat carrier (water) to recuperative heat exchangers, made in such a way that hot water enters heat exchangers located on the discharge side of the fans, and cold water enters heat exchangers located on the suction side of the fans, and when the air stream is reversed, flows of cold and hot water change the direction of their movement; moreover, all recuperative heat exchangers have condensate traps and steam traps, and the absorption heat pump is located outside the drying chamber.

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