SU1232915A1 - Recuperator for heating and heat-treating furnaces - Google Patents

Description

The invention relates to a metallurgical heat technology and can be used to heat the air going to burn gaseous or sour fuels by utilizing the heat from the exhaust flue gases from industrial heating and thermal furnaces.

The aim of the invention is to increase the efficiency and reliability of the heat exchanger.

FIG. 1 shows a recuperator, a section in FIG. 2 shows section A-A in FIG. I; in fig. 3 is the same as the embodiment.

The recuperator contains a heat-exchanging cavity 1 limited by a heat-transferring wall 2.

In front of the heat transfer wall 2 there is an air submersible cavity, made in the form of a series of pipes 3 connected by a common manifold 4 to a branch pipe. 5 cold air intake.

The heat transfer wall 2 is made in the form of interconnected arcuate elements 6, covering (each pipe 3). This wall 2, shock walls 7 and 8 and the top sheet 9 form a closed duct 10 with a pipe 1I for exhausting heated air and an air vent, th cavity 1 2.

The collector 4 is outside the box 10, and its cross-sectional area exceeds more than three times the total cross-sectional area of the pipes 3 entering it

The pipes 3 pass through the entire length of the box 10 and are plugged from the end 13. The pipes 3 can be made tapering towards the plugged end 13, and to reduce heat loss they can be made double, i.e. coaxially arranged in each other with the formation of an air gap between them. When this gap is located against each other (not shown).

Each pipe 3 is provided with a gap

1.4 along the generatrix facing the heat transfer wall 2.

The area of the gap 14 is made in

3.5 times smaller than the cross-sectional area of the pipe 3.

To increase the temperature of the air preheating, the air exhaust cavity I2 can be connected to the air supply pipe I through to pipes 3 of the following

the air flow is similar to that of a recuperator (Fig. 3).

Outside, the heat exchanger has heat insulation (not shown in the drawing).

The recuperator operates as follows.

The flue gases pass through the flue duct (not shown), washing the heat transfer wall 2. Cold air flows through the nozzle 5 into the air inlet manifold 4, and then into the pipes 3. Passage through the pipes 3, the air flows through the slits 14 to the arcuate elements 6 of the heat transfer wall 2. Turning along these elements 6 and heating, the air flow, the passage between the pipes 3, enters the air-exhausting cavity 12, and then discharges through the pipe I1 from the heat exchanger.

This slit bore size is optimal, since with a value of 2.5 it is impossible to obtain a uniform distribution of air flow along the length of the slit, which will lead to uneven cooling of the heat-transmitting wall along the length,

(along the slit), and at a value of 8, uneven cooling of each arc-shaped element of the heat-transmitting wall along the width (across the cross section) will take place.

The implementation of the air supply cavity in the form of a series of connected common number I. -,

a pipe lecturer

each of which is provided with a gap along the generatrix facing the heat transfer wall, and

at the same time, the heat transfer wall in the form of interconnected arcuate elements encompassing each pipe, prevents the formation of sections on the heat transfer wall without washing with cold air, which prevents these burnouts and early failure, and therefore, increases reliability completely. eliminates the curvature of the trajectories of air streams by the flow of heated air and the mixing of cold air with heated air.

In addition, the specified constructive implementation of the heat transfer wall increases the total surface of the Heating, washed by the flue gases H with cold air, allows you to avoid collisions of heated air after it leaves the slots from the adjacent air supply pipes and eliminate stagnant zones on the air side of the wall, as well as avoid its warping under the influence of high temperatures.

Thus, the proposed constructive implementation of the heat exchanger

FigZ flue gases

Compiled by G.Nazarova

Editor N.Egorova Tehred M.Hodanich

Order 2756/39 Circulation 561 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, st. Project, 4

2329154

allows you to increase its efficiency and reliability.

The use of a heat exchanger will allow greater heat production per unit of heating surface, a higher heat transfer coefficient, will increase the reliability and service life of the heat exchanger, as well as reduce fuel consumption for heating of heating and thermal furnaces.

LA

FIG. 2

Corrector v.Sinitska

Claims (3)

The invention relates to metallurgical heat engineering and may find application for heating air going to burn gaseous or liquid fuels by using the heat of exhaust flue gases from industrial heating and thermal furnaces. The aim of the invention is to increase the efficiency and reliability of the recuperator. In FIG. 1 shows a recuperator, section) in FIG. 2 is a section AA in FIG. G; in FIG. 3 - the same embodiment. The recuperator contains a heat exchange cavity 1 bounded by a heat transfer wall 2. In front of the heat transfer wall 2 there is an air supply cavity made in the form of a series of pipes 3 connected by a common collector 4 with a pipe. 5 supply of cold air. The heat transfer wall 2 is made in the form of interconnected arcuate elements 6, covering each pipe 3. This wall 2, Zokovye walls 7 and 8 and the top sheet 9 form a closed box 10 with a pipe 11 for venting heated air and an exhaust cavity 12. The collector 4 is placed outside the box 10, and its cross-sectional area exceeds more than three times the total cross-sectional area of the pipes 3 included in it. Pipes 3 extend over the entire length of duct 10 and are plugged from end face 13. Pipes 3 ‘can be made tapering towards the plugged end 13, and to reduce heat loss they can be made double, i.e. coaxially arranged in each other with the formation of an air gap between them. In this case, the slots are located opposite each other (not shown in the drawing). Each pipe 3 is provided with a slit 14 along the generatrix facing the heat transfer wall 2. The area of the slit 14 is made 3.5 times smaller than the cross-sectional area of the pipe 3. To increase the temperature of the air heating, the air exhaust cavity 12 can be connected to the air supply pipes 3 of a similar heat exchanger following the air flow (Fig. 3). Outside the recuperator has thermal insulation (not shown in the drawing). The recuperator works as follows. Flue gases pass through the gas duct (not shown in the drawing), washing the heat transfer wall 2. Cold air through the pipe 5 enters the manifold 4 of the air supply cavity, and then into the pipes 3. Passing through the pipes 3, the air flows through the slots 14 onto the arcuate elements 6 heat transfer wall 2. Unfolding along these elements 6 and heating up, the air flow passing between the pipes 3 enters the air outlet 12, and then through the pipe 11 is discharged from the recuperator. The indicated value of the cross-sectional area of the slit is optimal, since with a value of <2.5 it is impossible to obtain a uniform distribution of air flow along the length of the slit, which will lead to uneven cooling of the heat-transmitting wall along the length (along the slit), and with a value of> 8 uneven cooling of each arcuate element of the heat transfer wall in width (across the cross section). The implementation of the air supply cavity in the form of a series of pipes connected by a common collector and plugged from the end, each of which is provided with a slit along the generatrix facing the heat transfer wall, and the implementation of the heat transfer wall in the form of interconnected arcuate elements covering each pipe, eliminates the formation of sections on heat transfer wall, not washed by jet cold air, which prevents burnout and premature failure, and therefore increases reliability completely. eliminates the curvature of the trajectories of air jets by a stream of heated air and mixing cold air with heated. In addition, the indicated design of the heat transfer wall increases the total surface heated by flue gases] and cold air, avoids collisions of heated air flows after it leaves the slots of adjacent air supply pipes and eliminates stagnant zones from the air side of the wall, as well as avoids it warping under the influence of high temperatures. Thus, the proposed design of the recuperator can improve its efficiency and reliability. The use of a recuperator will make it possible to have a higher heat output per unit of heating surface, a larger heat transfer coefficient, increase the reliability and service life of the recuperator, and also reduce fuel consumption for heating heating and thermal furnaces.