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INVENTION
Russian Federation Patent RU2265160

process heaters

process heaters

Name of the inventor: Dobriansky VL (RU); Zaretsky YV (RU); Rysev VV (RU); Serazetdinov F.Sh.
The name of the patentee: Limited Liability Company "Aviagaz-Union"
Address for correspondence: 420036, Kazan, st. Dementieva, 1, OOO "Aviagaz-Union"
Starting date of the patent: 2004.05.31

The invention is intended for heating of liquids and gases and mixtures thereof may be used in various industries. The heater comprises a burner, a vertically mounted shell and tube heat exchanger, shielded, at least two belts bayonet tubes with annular gap and the inner tubes that communicate with removable nozzles mounted in the bottom of the heater input and output manifolds heated medium. The swirler annulus mounted. Directly behind the ring that supports the bayonet tube and limiting the combustion zone wall, near the axis of the heater is not occupied by the pipes, mounted fairing in the form of a hollow cylinder coaxial with the casing of the heat exchanger and chimney, and its cone apex facing toward the burner so that the annular space between the fairing and the casing filled tubes, forms a cavity convection section. In this case, said section ends in front of the chimney equally spaced on the diameter of the fairing holes oriented against the gaps between the bayonet tubes the inner belt tubular heat exchanger bundle. The present invention provides improved operational reliability and efficiency of the heater.

DESCRIPTION OF THE INVENTION

The invention relates to a device intended for heating of liquids, gases and mixtures thereof to the effectiveness of production processes and can be used in various industries, for example for heating gas inlet distribution stations to prevent adverse effects decomposition of gas hydrates accompanying throttling process gas.

Known process heater (see. №2168121 Russian patent, Int. 7 F 24 H 3/08 of 14.09.1999), comprising a horizontally mounted shell and tube heat exchanger, a shielded two zones of heat exchanger tubes, equally spaced relation to the inner wall of the housing and coaxial with each other in such a way that the same in structure, length and number of tubes of the outer and inner zones within the furnace volume from the burner supported in annular partition holes, fixed to the inner wall of the housing and at the other end to the rear bottom of the flue duct openings, and all the heat exchange tubes are inserted one into the other so-called bayonet-tubes, the outer of which are made with the closed end facing towards the burner, and at the other end, outside of the flue duct, the working chamber of each of the heat exchange tubes communicated with the nozzles removable inlet and outlet manifolds of the heated medium.

Revealed in practice, the main drawback of the known process heater is as follows.

Often in reality needful flow range of the heated gas (and therefore heat output of the burner) can be changed (reduced) 20 times the nominal value. This fact leads to the fact that at very low speeds expiration gas mixture from the burner installed horizontally in the combustion chamber, the torch may be bent under the action of the buoyant forces, leading to substantial non-uniformity of the temperature field in the cross section of the heating gas. And to such a degree that in the bottom of the tube bundle condense water vapor contained in the heating gas, leading to corrosion of the heat exchanger and the casing, as a consequence - reducing the resource and efficiency (COP) of the manufacturing of the heater as a whole.

This drawback is at least in part reducing the efficiency is largely eliminated in the process heater (Patent of Russia №2189476, kl.7 F 02 C 7/20 from 08.11.2000 g) made as a vertically mounted tube heat exchanger, shielded by at least two belts bayonet tubes, the annular gap and the inner tube that communicated with removable nozzles with collectors of entry and exit of the heated medium, in which the annular gap bayonet tubes installed swirler configured as a wire helically wound over the entire length of the inner tubes, moreover, in the axial portion of the heater is not occupied by pipes installed bluff body in the form of a cone coaxial with the casing and the stack and its vertex facing towards the torch so that the length of the furnace volume on the heat exchanger axis bounded at one end porthole burner with another - a bluff body, no less than the maximum value range of a torch burner (prototype).

Disadvantages of the known heater are as follows. Firstly, the absence of transverse partition that prevents deflections and vibrations of pipes and ensuring the movement of the heating gas in the annulus across the tube bundle in order to intensify heat transfer, which reduces the reliability and efficiency of the heat exchanger, respectively. Secondly, the use of a single bluff body is not enough to ensure the required efficiency of the heater, that will have to compensate for the increase in its teplovosprinimayuschey surface.

The technical result of the invention is to increase the operational reliability and efficiency while significantly expanding the range of heat loads, maintaining ecological norms of emissions in the flue gases and reducing the cost of development and manufacture of the heater as a whole.

This result is achieved in the process heater made as a vertically mounted tube heat exchanger, shielded, at least two belts bayonet tubes, the annular gap and the inner tube that communicated with removable nozzles defined in the lower portion of the heater collector inlet and outlet of the heated medium, wherein in the annular gap bayonet tubes installed swirler configured as a wire helically wound over the entire length of the inner tubes, and the invention directly behind the annular supporting pipe wall bounding the combustion zone in the axial portion of the heater is not occupied by pipes mounted fairing in the form of a hollow cylinder coaxial to the casing and the stack, its vertex facing towards the torch so that the annular space between the outer diameter of the fairing and the inner diameter of casing filled pipes forming the convective section of the heat exchanger, which ends in front of the chimney equally spaced along the diameter of the fairing openings oriented internal against interstices between pipes belt, wherein the total sectional area of ​​the holes should be less than the cross sectional area of ​​the flue.

The drawing shows a general view of a process heater in longitudinal section in a section A-A.

process heaters

The heater comprises a source of heating medium, which is, for example, multi-threaded injection burner 1 (see. RF patent №2163325 from 19.07.1999 city) facing the torch toward the combustion zone 2 vertically mounted tube heat exchanger 3, shielded, at least two belts bayonet tubes 4 and 5, the annular gap 6 and the inner tube 7 which are communicated with removable nozzles 8 defined in the lower portion of the heater outlet manifolds 9 and 10 input respectively of the heated medium. In the annular space 6 is set swirler 11 formed, for example, as a wire helically wound throughout the length of the inner pipes 7.

For annular supporting tube wall 12 bounding the combustion zone 2 in the axial portion of the heater is not occupied by pipes mounted fairing 13 in the form of a hollow cylinder coaxial with the casing and the stack 14 and its cone apex 15 facing toward the burner so that the annular space between the outer diameter and the inner diameter of the fairing forms a cavity housing a convective heat exchanger section 16 which ends in front of the chimney cowl diameter equally spaced openings (e.g., rectangular section) 17 oriented against the gaps between the inner tubes of the heat exchanger tube 4, the beam waist. Thus the total cross-sectional area of ​​apertures 17 should not be less than the cross sectional area of ​​the flue. In appointing the size (diameter and length of the combustion zone 2) recommend guided by the data given in the reference company Weishaupt directory.

HEATER WORKS AS FOLLOWS

Heated medium, for example purified natural gas from the pipeline enters the inlet manifold 10 to branch pipes 8 into the inner tube 7 both belts bayonet tubes 4 and 5. After turning relative to the closed end of the outer tube at the end of the convection section 16, the gas enters the annular gaps 6, where, moving in the direction of the burner 1 is heated from the outer walls of the pipes, which are washed in a complicated way hot counter flow of the combustion products moving upwards towards the chimney 14. Thus, by the most optimal scheme of counter-movement of coolant (heating and heated gas). The heated heat exchange in the annular gaps pipes gas nozzles 8 enters the outlet manifold 9, where the reduction unit is conveyed to the distribution station.

The heating medium (combustion) in the form of high temperature flows from the torch burner 1 embrasures in the combustion zone 2. The overall complex flow pattern of the combustion products, however, conventionally the heat exchange process sequence is as follows. In front of the tube bundle from the loopholes of the burner to an annular baffle 12, part of the hot gas, moving practically in a radial direction and flowing around the double row of heat exchange tubes forms a relatively slow current so-called bypass stream which substantially cools and reaches the inner wall of the housing 3 of the combustion zone with temperature, eliminating overheating and, moving further along the tube bundle, continues to cool.

When approaching the partition 12 substantially cooled (eg, to a temperature of 300 ° C) the flow change the direction of movement by a sudden constriction in the septum hole, where he meets with a hot axial flow, the temperature of which has been reduced due to the absorption of its radiant energy walls predominantly inner belt shielding pipes . Skirting the top of the cone 15 of the fairing 13, the axial hot stream (for example, with a temperature of 700-900 ° C) interacts with a "cold" bypass. After mixing these heating gases flow temperature remains high enough to ensure effective heat transfer in the convection section 16 within the heat exchanger. Mixing these streams in the annular channel formed by the partition and the cone apex of the fairing, and is accompanied by a reversal in the flow spreading radially, thus effectively giving heat in crossflow tube bundle tubes, at least at the initial and final portions of the convective section. At the end portion of the convection section of the cooled combustion products through holes 17 are input to the chimney.

Thus, vertically installing a shell and tube heat exchanger, shielded, at least two belts bayonet tubes by expanding the tube bundle by a partition in combination with a fairing, thereby significantly increasing the efficiency of the convection section, it was possible to achieve the main technical effect of the invention: improvement of operational reliability and effectiveness in a significant expansion of the thermal load, preservation of ecological norms of harmful emissions in the flue gases and reducing the cost of development and manufacture of the heater as a whole.

CLAIM

Process heater comprising a source of heating medium, such as a burner, a vertically mounted shell and tube heat exchanger, shielded, at least two belts bayonet tubes with annular gap and the inner tubes that communicate with removable nozzles defined in the lower portion of the heater collector output and input of the heated medium, respectively wherein the annular gap is set swirler configured, for example as a wire helically wound throughout the length of the inner pipes, characterized in that directly behind the annular supporting bayonet tubes and bounding the combustion zone wall, in the axial portion of the heater is not occupied by the tubes, mounted fairing in the form of a hollow cylinder coaxial with the heat exchanger casing and the stack and its cone apex facing toward the burner so that the annular space between the fairing and the casing filled tubes forms a cavity convection section, wherein said section ends in front of the smoke pipe diameter equally spaced apertures fairing oriented against the gaps between the tubes of the heat exchanger tube of the inner belt beam, wherein the total sectional area of ​​the holes should be less than the cross sectional area of ​​the flue.

print version
Publication date 25.03.2007gg