SU998495A1 - Multiple-line tubular furnace - Google Patents

Description

(54) MULTI-LINEAR TUBULAR FURNACE

I

The invention relates to a multi-linear tube furnace for indirect heating of gases or liquids, especially for the chemical industry, which consists of a radiation zone and a convection zone.

A multilinear tubular kiln in the form of a circular kiln is known in which a large number of tightly adjoining pipes flow from the annular distribution JQ on top of the heating zone, which run straight through the entire heating zone and flow into the annular too: heating manifold at bottom j. At the same time, a fully circular furnace consists of a single heating zone, in the upper part of which a displacement body is located. The furnace tube is equipped with a separate firebox. Jq

The disadvantage of this known design is that this system is limited to a single heating zone, which means that for heating the product in several zones, the heated product must be moved from one zone to another with the help of the distributor

and connecting pipelines between them ..

High performance tube furnaces may even require the installation of several systems one after the other in the same heating zone. The result is additional pressure and heat losses. The disadvantage of this known construction is also the fact that it has an annular distributor and a manifold, which requires large technological costs.

Known is also a multi-linear round tube furnace, in which multilinearity is realized. horizontal rings of pipes or coils in front of the inner wall of the furnace, which lead from vertical distributors to vertical collectors. In this case, the distributors and collectors can be located both inside and outside the furnace space.

The disadvantage of this tube furnace is that a different amount of heat is supplied to the pipelines of this multilinear system along the height of the furnace space, since the heat transfer from the vertical flame is not constant in height. This leads to different throughput capacities in individual lines, which is not desirable, especially for processes with high product temperatures. In both known constructions of tubular furnaces, large pressure losses occur on the other hand due to repeated removal of the heated product and, on the other hand, uneven heat supply during heating. The purpose of the invention is to maintain low pressure losses during the operation of multiline tube furnaces for indirect heating of gases and liquids with uniform heat supply to all pipes, as well as reducing the cost of manufacturing and installation. This goal is achieved in that it creates a multi-linear tube furnace, which, in operation with optimal utilization of the heat content of the flue gas, is characterized by a small loss of pressure in the product flow with a sufficient distribution of the product along the individual pipe lines. At the same time, the manufacturing and installation costs must be reduced. The convection tubes, coming out of the distributor, are passed in a known manner through the convection zone and out of the convection zone without intermediate inclusion of a special intermediate collector, directly passing into the. radiation tubes. Radiation tubes have the same number of lines as convection tubes, or. multiple of them, are directed vertically downwards and then up one or more of the bottom in front of the wall through the radiation zone and flow into the horizontal collector, which is located above the radiation zone. Moreover, both convection pipes and directly connected radiation pipes of each line of pipes or only one radiation pipe are bent several times into a U-shape and the corresponding heat exchange zones pass. In addition, the distributor and manifold are divided into equal numbers isolated from the plots. The system of polygonal distribution of bodies and a collector instead of the well-known round structures is considered as the following preferential design. In addition, in the convection zone of the pipe, the opposite sides pass with a small distance from each other. FIG. 1 shows a tubular furnace cross section; in fig. 2 is a schematic representation of a cut-out part of the tubular system of a round furnace; in fig. 3 - the same as the box furnace. The furnace tube contains inlet pipe 1, distributor 2, convection pipe 3, radiation pipe 4, collector 5, propellant b, burner 7, wall 8, outlet pipe 9, flue gas channel 10, convection zone 11, and radiation 12. On the inlet pipeline 1, the product to be heated is fed to the distributor 2, From the distributor 2, which is located at the top of the convection zone 11 of the tubular furnace. Horizontally, there is a lot of vertical convection pipes 3 tightly adjoining each other. In the middle of the convection zone 11, the displacer 6 is located so that the flue gas from the radiation zone 12 is mo-. It only enters the flue gas channel 10 through the annular gap between the wall 8 and the displacer 6. The convection tubes 3 located in this annular gap can be made with an enlarged surface to improve heat transfer (studded, trimmed). From the convection zone, convection pipes 3 are transferred by the shortest, technically feasible way, without using an intermediate collector into radiation pipes 4. The radiation pipes 4 also pass again one side bottom next to each other wall 8. In such a constructional form it is also possible that the radiation pipes 4 are not arranged one side next to each other, but are provided with multi-sided ones. In this case, pipes 4, radiation 1, for one line, for example, can stand two-sided against each other or two-sided offset to each other. They are directed downwards, they pass through an i-shaped bend, and then pass directly over and flow into the horizontal collector 5, which is located horizontally. From the collector 5, the product is diverted through the outlet pipe 9. The number of radiation pipes 4 is a multiple of the number of convection pipes 3. However, the number of lines of convection pipe 3 and radiation pipe 4 is the same. It is also possible to replace the distributor 2 and the collector 5 with each other in their technological functions, if this is required by the product being heated. The amount of heat for indirect heating of the product is produced by burning a gaseous and / or liquid heat carrier in the burners 7 and transferred to the radiation zone to the study pipes 4 located in front of the wall 8 and to the convection zone 11 mainly by convective heat transfer of the flue gas 10 to convection pipes 3 , The flue gas channel 10 leaves the flue gas furnace.

It is also envisaged that the pipe system is designed in such a way that both convection pipes 3 and directly connected pipes 4 emissions from each individual pipe line or only pipes 4 radiation themselves are bent multiple times into a U-shape, provided that the number of pipes 4 radiation is a multiple of the number of convection pipes 3 of one line of pipes. This creates the premise that the heated product passes both heat transfer zones or radiation zone 12 several times.

For technological simplification, instead of a closed distribution (bodies 2 and closed collector 5, review by circumstances, it is possible to put identical and isolated sections of the distributor or collector by number. For round furnaces. It is particularly advantageous that the distributor 2 and the collector 5 are made polygonal, Since this results in a significant technological simplification, the advantage of the design is that the propellant 6 is excluded in the convection zone 11. Therefore, the convection zone 11 can be made in The cross section of the narrow and convection tubes of 3 opposite sides are located at a short distance from each other.

The distance of the convection tubes of 3 opposite sides can be reduced to a minimum, taking into account the surface-increasing finning or studing. ;

Claims (5)

1. Multiline tube furnace for indirect heating of gases or liquids, especially for chemical heating, having a radiation zone and a convection zone with a smaller a cross section for heat transfer, a distributor placed on top of the convection zone, a large number of tightly connected convection tubes connected to the distributor and fixed vertically in the convection zone between the wall and the displacer, differing in that the convection tubes 3 that go out from the distributor 2 and distributed in the convection zone 11 in the shortest way connected to radiation pipes 4 having a number of lines or a number of pipes that are multiples of the number of convection pipes 3 and made in the emission zone 12 single or multi-section arranged vertically downwards and then directed upwards in front of the wall 8 radiation zones and connected to a collector 5 located horizontally above the radiation zone 12. 2. Furnace according to claim 1, characterized in that the convection tubes 3 and radiation tubes 4 connected to them in the shortest way are bent several times into a U-shape and are located in the corresponding heat transfer zone. 3. Furnace according to claim. 1, characterized by the fact that the distributor 2 and the collector 5 are divided into an equal number of isolated sections. 4.Pech for PP.1 and 2, about the difference with the fact that the distributor 2 and the collector 5 are polygonal. 5.Pech on PP. 1-4, characterized in that the convection tubes 3 of opposite sides are located at a small distance between each other from each other vertically in a convection zone 11. It is recognized as an invention according to the results of the examination carried out by the Office for the Invention of the German Democratic Republic. ywsftivsd ipvvsiuchuchd prullh ./ FIG. I Fi & .3