KR20180078364A - Fired heater - Google Patents

Abstract

The present invention relates to a fire heater including a heating box accommodating one or more heating tubes, the one or more heating tubes for flowing of a heating target fluid in the inner portion installed in the heating box, and a burner forming a flame heating the outer surface of the heating tube. A flame guide adjusting the thickness and direction of the flame is formed around the flame nozzle of the burner. According to the present invention, an overheated region of the heating tube in the heating box in the fire heater is eliminated, and thus caulking can be addressed, the purity of a product can be enhanced, and the service life of the heating tube can be extended.

Description

Fire Heater {FIRED HEATER}

FIELD OF THE INVENTION The present invention relates to a fire heater of the type comprising one or more radiation sections through which the reactants are indirectly heated by the radiant energy provided by the burner and more particularly to a fire heater of a type capable of preventing the tube from over- To a fire heater having a flame guide.

Hydrocarbon conversion processes often use multiple reaction zones through which hydrocarbons flow. In order to perform the desired hydrocarbon conversion in each reaction zone, the reactants used in the process must be heated sufficiently in advance.

One known hydrocarbon conversion process may be catalytic reforming. Catalytic reforming generally involves the conversion of hydrocarbons used in the petroleum refining industry, dehydroisomerization of cyclohexane and dehydroisomerization of alkylcyclopentanes, dehydrogenation of paraffins to produce olefins, dehydrocyclization of paraffins and olefins, n Isomerization of paraffins, isomerization of alkyl cycloparaffins to produce cyclohexane, and the like. For example, propane is used in the field of semiconductor electronic materials such as the raw material use of SiC, which is a next generation power device material. Propane is required to have higher purity in order to be used in such a use.

Propane, propane, isobutane, and n-butane, for example, are contained in a high concentration as impurities in the raw material gas containing propane as a main component used as a raw material for producing high purity propane. As a method for purifying propane from the raw material gas, there are methods such as distillation, membrane separation, adsorption separation, absorption separation and the like, but it is necessary to set a large scale facility and precise distillation conditions. In such a hydrocarbon conversion process, a heating device such as a heater or furnace is used to heat the process fluid prior to the reaction. In order to heat reactants to a reaction temperature range in many chemical reaction processes, a fire heater is installed in front of each reactor. In the conventional fire heater, a tube through which a gas passes in a heat insulating box, It is heated by conduction or the like.

Fig. 1 is a schematic sectional view of a general fire heater, and Fig. 2 is a schematic view of a burner used in such a fire heater. As shown in FIG. 1, the fire heater includes a heating furnace heating box 10 equipped with a burner, and a heating tube 100 passing through the inside of the box and through which the reactant passes. The flame from the burner 20 conveys radiant heat to the heating tube extensively by the hot heat and the heat from the outer surface of the heating tube conveys heat received from the flame to the inside of the heating tube by the heat conduction phenomenon of the heating tube material Thereby heating the reaction product.

If the flame heat is uniformly distributed in the heating box, the reactant can be heated without deviating between the heating tubes, that is, the superheated region. However, since the flame is shaken by the small wind and is also influenced by the fuel gas flow inside the heating furnace, There is a very difficult limit to control the heat of the flame in the equipment.

If the heating tube in the heating box is not heated uniformly and the specific portion is overheated, the yield of the reaction may be lowered, and in particular, caulking may occur due to local heating at the portion where the flame reaches. Such caulking can reduce heat transfer through the tube, lowering the purity of the reactants, causing fouling, clogging the heating tube, damaging the heating tube, shortening the life of the heating tube, and even causing a rupture of the heating tube. Therefore, development of a fire heater capable of adjusting the flame of the burner is required.

U.S. Patent No. 8,197,250 discloses a fire heater comprising three or more channels and three or more burners for delivering a processing fluid, as shown in Figure 3, wherein at least two burners are positioned between the neutral position and the adjustment position And the burners at both ends of the burner are inclined toward the mounting surface at the adjustment position. This technique is intended to adjust the inclination of the flame so that the flame directly touches the heating tube or prevents overlapping of the flames. However, since the operation method is difficult and the flame is shaken by the air in the wind or the fire heater, Since the direction of the flame is not adjusted to the desired direction, the effect is not satisfied.

SUMMARY OF THE INVENTION It is an object of the present invention to overcome the limitations of the prior art described above by providing a flame guide on the burner outlet side of a fire heater to adjust the direction and width of the flame, The present invention provides a fire heater capable of minimizing a side reaction such as a pyrolysis reaction by eliminating an area overheated by direct contact and uniformizing the thermal distribution inside the fire heater.

Another object of the present invention is to provide a fire heater capable of suppressing the occurrence of caulking in the inside of a fire heater to produce a high purity product and to prolong the life of the heating tube.

According to an aspect of the present invention,

A fire heater including a heating box having at least one heating tube disposed therein, at least one heating tube in which the heating object fluid flows, provided inside the heating box, and a burner forming a flame for heating the outer surface of the heating tube And a flame guide for regulating the thickness and direction of the flame of the burner is formed around the flame injection opening of the burner to reduce radiant heat and increase convection heat.

The flame guide may be made of a non-combustible material such as brick, tile, or castable.

The flame guide may be formed inclined at an angle of 2 DEG to 15 DEG toward the flame.

The heating tube may be a U-shaped, coiled, or burned tube.

The U-shaped heating tube includes an inlet for introducing a reactant into a U-shaped heating tube, an outlet for cooling and collecting reactants from a U-shaped heating tube in fluid communication with the inlet, And a curved portion for providing fluid communication with the fluid. The U-shaped heating tube may be a U-shaped or inverted U-shaped tube.

According to the fire heaters of the various embodiments of the present invention, the width of the flame is reduced by the flame guide, the radiant heat transfer is reduced as the distance between the flame and the heating tube is increased, and the radiation heat is excessively radiated , Resulting in a more even distribution of heat. As a result, the heating tube satisfies the target value, but the temperature inside the furnace can be lowered to use a fire heater.

According to the fire heater of the present invention, the overheating region of the heating tube is removed, so that the occurrence of caulking can be greatly reduced, thereby increasing the purity of the product and maintaining the life of the tube for a long time. .

1 is a schematic sectional view of a fire heater.
2 is a schematic view for explaining the structure of a conventional burner of a fire heater.
3 is a schematic view showing an example of a conventional fire heater.
4 is a schematic view for explaining the structure of a burner of a fire heater according to an embodiment of the present invention.
5 is a schematic view for explaining the structure of a burner of a fire heater according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted.

The term "radiation section" as used herein generally refers to a section of a heater that receives heat radiated by fuel gas burned by, for example, a heater, primarily by radiation and convection heat transfer.

The term "burner" as used herein may include furnaces, charge heaters, or interheaters. The burner may include one or more combustors, and may include one or more radiation sections, one or more convection sections, or a combination of one or more radiation sections and one or more convection sections.

As used herein, the term "U-shaped heating tube" includes a reactant inlet and a reactant outlet, and a curvature between the inlet and outlet, wherein the inlet and outlet are arranged parallel to one another Refers to a tubular means, which means not only a U-shaped tube but also a structure including an inverted U-shape or a curved portion formed by a coil.

The fire heater of the present invention is a device for heating the heating tube evenly by reducing the phenomenon that the heat of the flame emitted from the burner is excessively radiated to a part of the heating tube. In the fire heater of the present invention, in order to reduce radiation heat and increase convection heat, the width (thickness) of the flame is reduced and the flame is heated with a thin flame, but the total amount of heat is kept the same.

In the fire heater of the present invention, the width of the flame can be reduced in two ways. First, the flame guide of the incombustible material is installed at the position where the flame is generated in the burner, One method is to adjust the shape of the flame in the initial section of the flame by making the flame guide narrower toward the direction of the flame. The flame guide is arranged parallel to the direction of the flame around the flame injection opening at the exit of the burner in parallel with the direction of the flame

FIG. 4 is a schematic perspective view of a fire heater according to an embodiment of the present invention, and FIG. 5 is a schematic perspective view of a fire heater according to another embodiment of the present invention. 4 and 5 show only the necessary equipment and lines for an understanding of the present invention and are not required for an understanding of the present invention and may be applied to pumps, compressors, heat exchangers and valves known to those skilled in the hydrocarbon processing arts. Are not shown.

One aspect of the present invention is directed to a method of manufacturing a heating tube, comprising: a heating box (10) having at least one heating tube (100) disposed therein; at least one heating tube (100) A flame guide (200) for adjusting the thickness and direction of the flame of the burner is formed around the flame injection opening of the burner to reduce radiant heat and increase convection heat The present invention relates to a fire heater.

The fire heaters of the present invention can be used for the reforming of hydrocarbon streams, pyrolysis of liquids or pyrolysis of gaseous aromatic and / or aliphatic hydrocarbon feedstocks such as ethane, propane and naphtha or by products such as ethylene and acetylene, propylene and butadiene It can be used for pyrolysis of gas oil to produce material.

The heating box 10 includes a plurality of burners 20 for exposing the outer surface of the heating tube to radiant heat. The burner 20 may be a charge heater or an interheater. Various known types of burners may be used including non-refined gases or premixed burners. The combustion air source may be taken from ambient air, or air preheated from the gas turbine exhaust. The heating box 10 is covered with an insulating refractory material to conserve thermal energy.

The heating box 10 includes at least one heating tube 100. The heating tube 100 may be a U-shaped, coiled, or burned tube. In a preferred embodiment, the heating tube takes a shape somewhat similar to the letter "U" character. The characteristic of the heating tube is to effectively form two passages through the heating box. The heating tube includes an inflow section 110, an outflow section 120 and a curved section 130 connecting the inflow section 110 and the outflow section 120. In another embodiment, the outlet 120 may include one or more branch tubes. The U-shaped heating tube 100 may be U-shaped or inverted U-shaped.

The flame guide 200 may be made of a non-flammable material such as bricks, tiles, castables, and scams.

Referring again to FIG. 4, the flame guide 200 may be installed parallel to the direction of the flame or may be inclined at an angle of 2 ° to 15 ° toward the flame of the burner. That is, the flame guide 200 may be installed inclined so that the inclination angle? In FIG. 4 is 2 ° to 15 °. Thus, the flame guide can be inclined to narrow the width in the direction of the flame, thereby controlling the shape of the flame in the initial period of the flame. At this time, the size (width) of the flame can be controlled by adjusting the inclination angle of the flame guide 200.

Referring to FIG. 5, a fire heater according to another embodiment of the present invention controls the size (width) of the flame, and the size (width) of the flame can be controlled by the angle of the flame guide 200 ' . The flame guide 200 'of the fire heater of FIG. 5 is installed at a larger angle (9 °) than the flame guide 200 of the fire heater of FIG. 4, The width w2 of the flame is controlled to be larger than the width w3 of the flame in FIG. 5 where the inclination angle is 9 ° (w2> w3).

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined by the appended claims. It will be understood that various modifications and changes may be made.

10: Heating box
20: Burner
100: heating tube
200, 200 ': Flame guide

Claims (5)

A fire heater including a heating box having at least one heating tube disposed therein, at least one heating tube in which the heating object fluid flows, provided inside the heating box, and a burner forming a flame for heating the outer surface of the heating tube And a flame guide is provided around the flame injection opening of the burner to adjust the thickness and direction of the flame of the burner to reduce radiant heat and increase convection heat.
The fire heater according to claim 1, wherein the flame guide is made of a non-combustible material.
The fire heater according to claim 1, wherein the flame guide is formed around the flame, parallel to the direction of the flame, or inclined at an angle of 2 to 15 degrees toward the flame.
The fire heater according to claim 1, wherein the heating tube is a U-shaped, coiled, or burned tube.
The fire heater according to claim 4, wherein the U-shaped heating tube is U-shaped or inverted U-shaped.

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