SU918739A1 - Heat-mass exchange apparatus - Google Patents

Description

(54) HEAT AND MASS EXCHANGE APPARATUS

one

The invention relates to heat and mass transfer, in particular to devices for cooling bulk materials, and can find wide application in the chemical, metallurgical, refractory, and other industries related to the cooling processes of powdered dust products.

Numerous designs of devices for cooling bulk materials are known by convective, conductive, or combined heat transfer from the material to the refrigerant (liquid or gas).

In particular, heat and mass transfer is known, which contains a rotating drum with a nozzle inside 1.

However, in this heat and mass exchanger, large amounts of energy are required to cool bulk materials.

Also known are heat and mass transfer apparatus, which contains a fluidized bed chamber with a gas distribution grid for supplying cold air and a transporting device for moving the material.

Owing to the developed contact surface, such devices are highly efficient 2.

However, at the same time with intensive cooling, these devices undergo intensive removal of the smallest fractions of the material, for the capture of which additional equipment is required. As a result, such a cooling scheme turns out to be cumbersome and very metal-intensive, especially when cooling fine materials.

Coolant bulk material coolers are known that contain a vertical shaft of rectangular or circular cross section and tubular cooling elements that are located along or across the shaft. The cooled material is lowered by gravity into the mine with a regulated release from below. The cooling is carried out by a refrigerant moving in the tubular elements 3.

Claims (4)

A significant disadvantage of this type of coolers is the low values of the average heat transfer coefficients from the material to the refrigerant, due to the formation of stagnant or slow-moving material zones around the cooling elements. Attempts to combine conductive cooling with convective, in order to intensify the mixing of materials in the annular space, inevitably leads to dust removal of small fractions, and as a result, to the complexity of the design. The closest to the proposed technical essence and the achieved result is a heat and mass transfer apparatus for cooling bulk materials containing a rotating drum with tubular elements inside to move the material, located along the drum in diametrical planes and connected at the ends to distribution chambers 4. As in this device the bulk material moves in tubular elements that are made straight, it is characterized by low cooling intensity, due to the small oh surface heat transfer. The purpose of the invention is to intensify the cooling process. The goal is achieved by the fact that the tubular elements are made zigzag along the length of the drum and are equipped with redistributive heads, the latter and the distribution chambers being made in the form of truncated cones. In addition, the ridges of tubular elements are arranged at an angle to the horizontal, the greater angle of repose of the material. Moreover, the distribution chambers and redistribution heads are made with a taper angle less than the angle of repose of the material. FIG. 1 schematically shows the proposed heat and mass transfer apparatus; in fig. 2 shows section A-A in FIG. 1. The heat and mass transfer apparatus contains an inclined rotating drum 1 with heat exchanging tubular elements 2 inside, made zigzag along the length of the drum. The elements 2 are located in diametrically-longitudinal planes near the inner surface of the wall of the drum 1 and are rigidly attached to it. At both ends of the drum there are distribution chambers 3 and 4 in the form of truncated cones, to which elements 2 are connected. Along the length of drum 1 there are one or several (depending on the drum length) redistribution heads 5 of the same design as with chambers 3 and 4. At both ends, the drum I is closed by covers 6, to which both distribution chambers 3 and 4 are hermetically attached. material. Input of cooling, water or other coolant into the internal cavity of the drum-. 1 is carried out along pipe 7, which is located along its axis and ends up with a splash head 8. The level of the refrigerant in drum 1 is adjusted by changing the height of the holes 9 in the lid 6 adjacent to chamber 4. The drum has a loading chute 10, a discharge bin II and drain funnel 12 for water. Heat and mass transfer apparatus operates as follows. The cooled bulk material is fed while the drum 1 rotates through the chute 10 into the upper distribution chamber 3 and is distributed over all the heat exchanging tubular elements 2. In the elements 2 it performs a complex reciprocating motion, moving along them and along the redistribution heads 5 into the lower chamber 4 drum 1 and then it is discharged through the hopper Ih. Cooling water supplied through pipe 7 through nozzles 8 irrigates the heat exchange elements 2 and flows down to the bottom of the drum. The water level in the drum is controlled by the height of the holes 9. Water is drained through the funnel 12. As the drum rotates, the tubular elements 2 are alternately submerged in water in the lower part of the drum. Further, with the help of tubular elements 2, part of the water rises and intensively irrigates the downstream elements 2. The corners of the ridges of the elements 2 and the taper of the chambers 3, 4 and heads 5 are chosen so as to prevent the material from clogging the elements. Thus, due to the intensive movement of the cooled material in the tubular elements and the rational organization of the contact of these elements with the cooling water in the apparatus, high values of heat transfer coefficients are achieved. Claim 1. A heat and mass transfer apparatus for predominantly cooling bulk materials comprising a rotating drum with tubular elements inside to transfer material arranged along the drum in diametrical planes and connected at the ends to distribution chambers, characterized in that, in order to intensify the cooling process, the tubular the elements are made zigzag along the length of the drum and are equipped with redistributive heads, and the heads and distribution chambers are made in the form of truncated cones. 2. The apparatus according to claim 1, characterized in that the tubular elements are arranged at an angle to the horizontal, a greater angle of repose material 3. An apparatus according to claim 1, characterized in that the distribution chambers and redistribution heads are made with a taper angle smaller than the angle of repose of the material. Sources of information taken into account in the examination 1. Balaika B., Sikora K - Heat exchange processes in chemical industry apparatuses. M., Mashgiz, 1962, p. 542-243. 2.Romankov P.G., Rashkovska N. .. B. Drying in a knp layer. M., - L., “Himi, 1964, p. 125, 126. 3. Gorbis 3. R. Heat exchangers with flow dispersed heat carriers. M., “Chemistry, 1975, p. 99 4.Filippov V.A. Technique and technology of drying coal. M., "Nedra, 1975, p. 120-121.