RU2696522C1 - Heater for track heater - Google Patents

Abstract

FIELD: heating.

SUBSTANCE: invention relates to liquid medium heaters, in particular, to furnaces for track heaters with liquid heat carrier. Heater for track heater is U-shaped tube and is equipped with through overflow tubes arranged in the furnace convection zone at an angle to the horizontal. Through overflow tubes are arranged in staggered order at an angle to horizontal 25–90°, and through diameters outer diameter overflow tubes is 36–70 mm.

EFFECT: invention allows reducing temperature of flue gases, increasing surface of heat exchange of convective zone by more than two times, increasing efficiency factor, increasing heat output of track heater.

1 cl, 3 dwg, 1 tbl

Description

The invention relates to liquid heaters, in particular to furnaces for track heaters with a liquid coolant, for example, in the form of an aqueous solution of diethylene glycol, and can be used in the chemical and oil refining industries for heating an oil emulsion or oil.

From A.S. No. 1744406 (USSR IPC ⁵ 28D 1/02, publ. 06/30/1992, Bull. No. 24) known furnace (heat pipe) of a tubular heater of liquid or gaseous media, which inside has a hollow axisymmetrically located insert, communicated from the upper and lower ends with a body cavity. The flame tube is equipped with through pipes. In the process of operation of the heater, the inclusion of the flame tube leads to the movement of the coolant in the upper part of the insert and its spreading over the nozzles.

Common features of the well-known and patented firebox are the shape in the form of a pipe, as well as the placement of nozzles in the furnaces intended for the flow of coolant.

In A.S. No. 1561612, (USSR M. Cl. F22B 7/00, publ. 10/05/1987.) A furnace (horizontal flue) is described. In the gas duct, the products of fuel combustion (heat source) move in the forward and reverse directions. Heat transfer tubes are made with fixed ends in the lower and upper flat walls of the duct.

Common features of the known and patented firebox are the shape in the form of a pipe and the content in the furnaces of heat-exchange (transfer) tubes.

In the patent No. 2655096 (RU IPC F22B 7/00, publ. 05.23.2018, Bull. No. 15) a furnace (heat pipe) of a tubular heater for heat treatment of thermolabile and thermally unstable liquids is described. Turbulent rings are placed in the flame tube, and tubes are placed at an angle to the horizontal, which open ends enter the jacket with an intermediate coolant.

Common features of the well-known and patented firebox are the shape in the form of a pipe, as well as the placement of tubes in the furnaces for the flow of coolant.

From the patent No. 2380611 (RU IPC F22B 7/00, published on January 27, 2010, Bull. No. 3), a furnace (furnace chamber) of an oil heater is known, which has a U-shape and contains transverse transfer tubes.

The common features of the well-known and patented firebox are the U-shape and the presence in the furnaces of tubes for the flow of coolant.

From the patent No. 2613008 (RU IPK F22B 7/00, published March 14, 2017, Bull. No. 8, see the description of the patent in the 7th paragraph), a U-shaped furnace for a track oil heater of the PP-1.6 / PP series is known -four. The furnace is installed in the inner cavity (in the lower part) of the heater, which is a cylindrical horizontal tank with a flat bottom.

The tank is filled with liquid heat carrier (diethylene glycol).

Furnace devices are equipped with burners:

- gas in the PP-1.6 model; PP-4; PP-4V;

- liquid-fuel in the PP-1,6Zh model;

- combined in the model PP-1,6-K.

The fuel preparation and supply units for the burner devices are mounted outside the heater, which is also equipped with a coolant level indicator, a ladder and a service platform.

The heater operates as follows. The product is fed into the coils for heating to + 70 ° C from the coolant. The temperature of the coolant is supported by automation + 95 ° C by controlling the power of the burners. The automation system of the heater PP-1,6 / -4 provides:

- regulation of fuel pressure in front of the burners;

- ignition of burners;

- maintaining the temperature of the product by automatically changing the burner mode from large to small combustion and vice versa;

- automatic shutdown of fuel supply to the burners with decoding and storing the root cause in case of:

- increase the pressure of gaseous fuel in front of the burners;

- lowering the fuel pressure in front of the burners;

- extinction of torch torches;

- increase the temperature of the coolant;

- increase the pressure in the food coil.

A common feature of the well-known and patented firebox is the U-shape.

The disadvantages of this analogue are:

- small dimensions of the convection zone;

- the transfer of thermal energy in the radiant zone significantly exceeds the amount of heat transferred in the convection zone of the furnace;

- increase in flue gas temperature at high loads;

- lower thermal efficiency (COP) of the track heater, equipped with a well-known firebox.

Patent No. 74190 (RU IPC F22B 7/00, publ. 06/20/2008 Bull. No. 17) describes the closest (prototype) fire chamber for the track heater in the form of a U-shaped pipe in the convection zone at an angle to the horizontal welded through transverse transfer pipes. In this case, the transfer pipes have a maximum diameter and are arranged in such a way that they form a spiral inside the furnace space, and in the U-shaped transition of the radiation-convection chamber into the convection, transfer pipes of the maximum possible diameter are also welded, forming a spiral with a linearly angular pitch.

The disadvantages of the prototype are:

- the presence of pipes in the radiant part of the furnace can lead to local overheating and depressurization of the transverse transfer pipes;

- not optimal pipe diameter;

- the presence of transverse transfer pipes in the U-shaped transition leads to an increase in the hydraulic resistance of the furnace.

The technical task of the claimed invention is to expand the range of means for heating oil and oil products during their transportation by transferring thermal energy from the furnace to the coolant, and from the latter to the product.

The set of essential features in the claimed invention allows to obtain the following technical result:

- lowering the temperature of the flue gases at the outlet of the chimney;

- an increase in the heat exchange surface of the convective zone;

- increase in thermal efficiency (Efficiency);

- improving the technical and economic indicators of the track heater, equipped with a patented firebox.

The elimination of these drawbacks of the prototype and the technical result from the implementation of the furnace for the track heater of oil emulsion or oil, which is a U-shaped pipe and equipped with through-flow transfer tubes placed in the convection zone of the furnace at an angle to the horizontal, is achieved due to the fact that the furnace is equipped with through-flow transfer tubes whose outer diameter is 36-70 mm. When this tube is placed in the convection zone of the furnace in a checkerboard pattern at an angle to the horizontal (to the axis of the furnace). The angle of inclination is 25-90 °.

A comparative analysis of the prototype and the inventive firebox shows that both fire chambers are a U-shaped pipe equipped with through-flow transfer tubes placed in the convection zone of the firebox at an angle to the horizontal.

A distinctive feature of the inventive furnace for a track heater is that the furnace is equipped with through-flow transfer tubes, the outer diameter of which is 36-70 mm. When this tube is placed in the convection zone of the furnace in a checkerboard pattern at an angle to the horizontal (to the axis of the furnace). The angle of inclination is 25-90 °.

The invention is illustrated in FIG. one.

In FIG. 1. presents a General view of the patented firebox for the track heater type PP-4V, where positions 1-6 indicate:

1 - radiant zone;

2 - convection zone;

3 - tap;

4 - chimney;

5 - burner device;

6 - through transfer pipes.

The radiant zone 1 is the space inside the furnace from the flange of the burner 5 to the outlet 3, and the convective zone 2 is from the outlet 3 to the chimney flange 4. The outlet 3 is a U-shaped junction. The furnace is equipped with a chimney 4 and a burner 5. Through-flow transfer pipes 6, the outer diameter of which is 57 mm, are placed in the convection zone of the furnace. The tubes are staggered at an angle to the horizontal (to the axis of the furnace). The angle of inclination is 50 °.

The furnace is a U-shaped pipe having flange connections on both sides for mounting the burner device 5 of the chimney 4. In the radiant zone of the furnace 1 (from the burner device flange 5 to the exhaust 3), the main heat transfer occurs due to the transfer of thermal energy (radiation) when burning fuel. In the convection zone of the furnace 2 (from outlet 3 to the chimney flange 4), heat transfer is due to convective heat transfer due to the transfer of thermal energy by flue gases.

In FIG. 2. A general view of a standard firebox for a track heater of the PP-4V type (analog) with a similar FIG. 1 by a list of figures (with the exception of position 6 - through transfer pipes).

The furnace is a U-shaped pipe having flange connections on both sides for mounting the burner device 5 of the chimney 4. In the radiant zone of the furnace 1 (from the burner device flange 5 to the exhaust 3), the main heat transfer occurs due to the transfer of thermal energy (radiation) when burning fuel. In the convection zone of the furnace 2 (from outlet 3 to the chimney flange 4), heat transfer is due to convective heat transfer due to the transfer of thermal energy by flue gases.

In FIG. 3. presents a longitudinal section of the heater. Structurally, the track heater is a cylindrical horizontal tank with a volume of 100 m ³ with a flat bottom. In the upper part of the heater, a grocery tubular coil is installed, into which oil is supplied. In the lower part of the heater two standard fire chambers are installed (Fig. 2. analog) having flange connections on both sides. A burner is attached to one flange of the heater furnace, and a chimney to the other.

Heating oil is as follows. The inner part of the tank is filled with a liquid intermediate coolant, which is used as an aqueous solution of ethylene glycol. Fuel (commercial oil) is supplied to the burner device of the heater furnace. The furnace is designed to transfer heat from combustion products to a heated product by means of an intermediate heat carrier. When burning fuel in a burner, the furnace and the liquid intermediate heat carrier are heated. Oil in the amount of 422 t / h is heated in the food coil from the intermediate coolant, and then removed from the heater. Combustion products are removed from the furnace using a chimney.

The essence of the present invention is further described using the following implementation examples.

Example 1 (for comparison). Oil heating is carried out in a traveling heater type PP-4V, equipped with a standard firebox (analogue).

Example 2 (for comparison). The oil heating in the track heater according to example 1 with the difference that the heater is equipped with two fire chambers of the prototype.

Example 3 Oil heating in a traveling heater according to Example 1 with the difference that the heater is equipped with two patented fire chambers (Fig. 1), in the convection zones of which through-flow transfer tubes with an external diameter of 70 mm are placed. The tubes are staggered at an angle to the horizontal (to the axis of the furnace). The angle of inclination is 25 °.

Example 4 Oil heating in a traveling heater according to Example 1 with the difference that the heater is equipped with two patented fire chambers (Fig. 1), in convective zones of which through-flow transfer tubes with an external diameter of 50 mm are placed. The tubes are staggered at an angle to the horizontal (to the axis of the furnace). The angle of inclination is 45 °.

Example 5 Oil heating in a traveling heater according to Example 1 with the difference that the heater is equipped with two patented fire chambers (Fig. 1), in convective zones of which through-flow transfer tubes with an external diameter of 36 mm are placed. The tubes are staggered at an angle to the horizontal (to the axis of the furnace). The angle of inclination is 90 °.

The table shows the comparative results of heating oil in a track heater equipped with fire chambers according to the analogue (example 1), according to the prototype (example 2) and fire chambers according to the invention (example 3-5).

The data given in the table confirms the effectiveness of the developed technical solution. Placing the transfer pipes in the convection zone provides a decrease in the temperature of the flue gases and an increase in the heat exchange surface of the convection zone by more than two times. The staggered arrangement of the transfer tubes prevents the formation of stagnant zones and a “near-wall” effect. When implementing the invention, the efficiency is significantly increased, the thermal power of the track heater and the temperature difference of the initial and final oil are increased.

The prototype disadvantages are eliminated. When using a patented firebox, the absence of local overheating and depressurization of the transfer flow tubes is shown, the hydraulic resistance of the firebox is reduced.

The optimal external diameter of the delivery transfer pipes and their angle of inclination to the horizontal were selected.

The step of the through transfer tubes is adopted taking into account the conservation of hydraulic resistance of the convective part of the furnace. The external diameter of the overflow transfer pipes is due to the design features of the convection part of the furnace. An increase in the external diameter of the overflow transfer pipes over 70 mm will lead to a decrease in their number and, as a result, to a decrease in the effective heat transfer area and a deterioration of the technical result. A decrease in the diameter of the overflow transfer pipes (less than 36 mm) will lead to a sharp increase in the hydraulic resistance of the convection zone of the furnace.

The angle of inclination of the overflow transfer pipes to the horizontal in the claimed intervals ensures an efficient convection process of movement of the coolant and the achievement of optimal heat transfer values.

Moreover, the claimed technical result is obtained not due to the additive contribution of each component, but due to the total synergistic effect.

Claims (1)

A furnace for a track heater, which is a U-shaped pipe and equipped with through-flow transfer pipes placed in the convection zone of the furnace at an angle to the horizontal, characterized in that the through-transfer pipes placed in the convection zone of the furnace are staggered at an angle to the horizontal 25 -90 °, and the outer diameter of the through transfer tubes is 36-70 mm.

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