SU870883A1 - Rotary furnace heat exchanging apparatus - Google Patents

Description

(54) HEAT TRANSFER-NOE DEVICE OF ROTATING FURNACE

I

The invention relates to the field of the building materials industry, mainly to the burning of cement clinker in rotary kilns.

A heat exchanger device for a rotary kiln is known that contains a Hbie on the inner surface of the kiln lining hollow pouring elements made in the form of ducts installed with a side plane at an acute angle and the kiln axis, above the upper plane of which there is a twisting blade 1 diagonally. the lateral plane of the pouring element and the twisting blade creates different speeds of movement of the material in the layer, in connection with which the material moves more intensively; When exiting the material, the pouring element lateral plane swirls the gas flow.

The drawback of the device is that it contains a large number of pouring elements, a relatively complex structure, creating a multitude of intersecting vortex flows that contribute little to the intensive heat exchange between the material and the gas flow. In addition, the design and arrangement of elements contribute little to an increase in heat transfer between the lining and the material.

The closest in technical essence and the achieved result to the described invention is a heat exchange device containing screw blades fixed on the inner surface of the furnace body, mounted at an angle of 45-60 ° K forming the furnace body and directed against the rotation of the furnace 2.

As the furnace rotates, the screw blades are heated and immersed in the material layer. When passing through a segment of material, the blades transfer heat to the material and the blades create equal speeds of movement of the material in the layer, as a result of which the mixing of the material and heat transfer in the furnace improve. When leaving the material, the screw blade swirls the passing gas stream, and therefore improves the heating of the lining with waste gases.

20

The disadvantage of the device is relatively inefficient heat transfer in the furnace. This is due to the fact that the material mixed by the screw blade has an insufficient contact surface with gases and the surface of the furnace lining. In addition, the screw blade has a relatively short length of time in contact with the material, and therefore it does not have time to transfer its heat to the material, due to which the blade heats up to the temperature of the gases, as a result of which its service life is reduced.

The aim of the invention is to intensify heat exchange in the furnace.

The goal is achieved by the fact that in a heat exchanger device of a rotary kiln containing screw blades fixed at the inner surface of the kiln shell, installed at an acute angle to the generator kiln shell and directed against the kiln rotation, each blade is made in the form of a rectangular trapezium attached to the kiln shell with a large base. and a directional side sloping side toward the movement of gases, with the height of the blades being 0.03-0.35 of the diameter of the furnace, the distance between the blades around the circumference of the furnace is 1.0-1.3 reasons for the smaller base of the trapezium.

FIG. 1 shows the proposed heat exchanger, cross section; in fig. 2 is a view A of FIG. one.

In the rotary kiln 1, the casing of which is internally covered with lining 2, screw blades 3 are mounted. The blades 3 are made in the form of a rectangular trapezium. The angle of the side 4 of the trapezoid to the large base is 45-70 °. Screw blades 3 to the furnace body 1 are fastened with a large base and side 4 directed towards the movement of gases, while the smaller base 5 of the trapezium is directed to the center of the furnace 1. Along the furnace 1 passes calcined material 6, Trapezoid blades 3 to the generator of the furnace body 1 is fixed under the opposite direction of rotation of the furnace 1 angle of 45-80 °. The height of the blades 3 installed in the same row is of the same size and is 0.03-0.35 times the diameter of the furnace 1. When installed in furnace 1 more than one row of blades 3, their height in different rows may be different. The height of the blades 3 in a row is determined by the conditions for achieving the intensity of heat exchange in the furnace 1. With a decrease in the height of the blades 3 less than 0.03 diameter of the furnace 1 is not achieved by an increase in heat transfer compared with the known technical solution. With an increase in the height of the blades 3 of more than 0.35 diameter of the furnace 1, a decrease in the degree of heat transfer is observed as compared with the presence in the furnace 1 of blades 3 with a height of less than 0.35 of the diameter of the furnace 1.

The distance in between the rows of blades 3 installed is 1.0-1.3 times the magnitude of a, a smaller base 5 of the trapezium. The distance between the blades 3 installed in the row is determined by the degree of movement and passage of the material between the blades 3 and the conditions of passage and turbulence of the gases. As the distance between the blades 3 increases, the degree of material passing through the blades 3 increases, the height of the layer from the cold end of the furnace 1 to the blade m 3 of material decreases, the area of contact of the material with gases and lining 2 decreases, as a result of which the heat exchange in the furnace 1 decreases. With a decrease in the distance between the blades 3 (), the resistance of the passage of gases between the blades 3 increases, the gases pass through the unbalanced central part of the furnace 1 and to a lesser extent wash away the located and passing through Asti material 3, whereby heat umenschaets.

The rows of blades 3 of the heat exchanger are installed along the length of the furnace 1. The distance between the rows of blades 3 is 0.5-10.0 times the diameter of the furnace 1.

The heat exchanging device is installed on the area occupied by the cell, chain curtains and other types of built-in furnace heat exchangers. With this, one row of blades 3 is installed in the hot end of the heat exchangers at a distance of 0.05-0.1 times the diameter of the furnace 1 from the boundary of the heat exchangers.

The device works as follows.

Claims (2)

By placing the blades 3 in the opposite direction of rotation of the furnace by the angle and inter-blade distance, the blades 3 repel the material against its movement and thereby create resistance to the passage of the material through the blades 3. The resistance created increases the layer of material suitable from the cold end the area of contact of the material with gases and lining 2, in connection with. than heat exchange increases. If there is resistance to the passage of material through the blades 3, the height of the layer of material increases to the height of the blades 3 and the material passes through the top of the blade row. In this case, when the furnace rotates, material is poured from one blade 3 to the next. Material is poured along the perpendicular side and the smaller base 5 of the trapezium. Toward side 4 of the trapezoid, furnace gases advance. Due to the presence of the counter angle (acute angle of side 4) in the trapezoidal blade 3, the concentric layers of the gas passing through the furnace 1 cross-section into the inter-blade space at different times, resulting in mixing of concentric layers and gas turbulization. The mixed and turbulent gas flow passes through the inter-blade channel and, meeting the material 3 filled with blades 3, intensively washes and heats it, and thus a high degree of heat exchange in the material passing through the blades is achieved. The advantage of the heat exchanger is to improve the heating of the material in the furnace. Claims of the invention Heat exchanging device of the rotary kiln, comprising screw blades fixed on the inner surface of the kiln shell, mounted at an acute angle to the generator of the kiln shell and directed against the kiln rotation, characterized in that. that, in order to intensify heat exchange, / J Fig. / Each blade is made in the form of a rectangular trapezium attached to the furnace body by a large base and directed sideways inclined towards the movement of gases, the height of the blades being 0.03-0.35 of the diameter of the furnace, and the distance between the blades the circumference of the furnace is 1.0-1.3 times the smaller base of the trapezium. Sources of information taken into account during the examination 1. USSR author's certificate No. 567059, cl. F 27 B 7/16, 1974. 2. USSR author's certificate number 606076, cl. F 27 B 7/16, 1976 (prototype). 4Si e // t / e HCf777epyff / 7ff % -. /