CN111765635B - An energy-saving and environmentally friendly thermal oil boiler - Google Patents

Abstract

The present invention discloses an energy-saving and environmentally friendly thermal oil boiler, comprising a boiler main unit, a waste heat boiler, and an air preheater; the waste heat boiler comprises a vertical main body; a vertical serpentine heat exchange tube is arranged in the vertical main body, and the straight tube section of the vertical serpentine heat exchange tube is inclined upward; the upper outlet of the vertical serpentine heat exchange tube is connected with the steam inlet of the drum; a centralized downcomer is arranged at the bottom of the drum, and a steam outlet pipe seat is arranged at the top of the drum; the air preheater comprises an external frame, and a plurality of vertical heat exchange tubes are arranged inside the external frame; the flue gas outlet of the boiler main unit is connected with the flue gas inlet at the top of the waste heat boiler; the flue gas outlet at the bottom of the waste heat boiler is connected with the vertical heat exchange tube in the air preheater. The present invention can effectively reduce the final exhaust gas temperature of the boiler by arranging a two-stage energy-saving device of a waste heat boiler and an air preheater at the tail end of the boiler main unit, so that the final exhaust gas temperature of the boiler is not higher than 100°C, which greatly improves the thermal efficiency of the boiler.

Description

An energy-saving and environmentally friendly thermal oil boiler

Technical Field

The invention belongs to the technical field of boilers, and in particular relates to an energy-saving and environment-friendly thermal oil boiler.

Background Art

Thermal oil boiler refers to a boiler that uses thermal oil as a heat carrier. It generally uses coal, oil, and gas as fuel and thermal oil as a heat carrier. Liquid phase thermal oil boilers use hot oil circulation pumps to force the medium to circulate in the liquid phase, and then return the heat energy to the heat-using equipment and then return it to the heating furnace for reheating. It can achieve a higher working temperature at a lower working pressure and save steel. Since the temperature of the medium in the thermal oil boiler is relatively high, usually at 260-320°C, the exhaust temperature of the boiler is also relatively high, usually above 300°C, resulting in energy waste and low thermal efficiency.

Therefore, it is urgent to design an energy-saving and environmentally friendly thermal oil boiler that can reduce the final exhaust temperature of the boiler to improve thermal efficiency.

Summary of the invention

The purpose of the present invention is to overcome the deficiencies of the above-mentioned prior art and provide an energy-saving and environmentally friendly thermal oil boiler.

To achieve the above object, the present invention adopts the following technical solutions:

An energy-saving and environmentally friendly thermal oil boiler comprises a boiler main unit, a waste heat boiler and an air preheater;

The waste heat boiler comprises a vertical body; a plurality of rows of vertical serpentine heat exchange tubes are arranged in the vertical body, and the straight tube sections of the vertical serpentine heat exchange tubes are inclined upward along the flow direction of the medium in the vertical serpentine heat exchange tubes; the upper outlet of the vertical serpentine heat exchange tubes is connected with the steam drum; a centralized downcomer is arranged at the bottom of the steam drum, and the centralized downcomer is connected with the lower inlet of the vertical serpentine heat exchange tubes through a lower water header; a steam outlet pipe seat is arranged at the top of the steam drum, and a water inlet pipe is arranged on the side wall of the steam drum;

The air preheater comprises an external frame, and a plurality of vertical heat exchange tubes are arranged inside the external frame;

The flue gas outlet of the main boiler is connected to the flue gas inlet at the top of the waste heat boiler through a flue gas duct; the flue gas outlet at the bottom of the waste heat boiler is connected to the vertical heat exchange tube in the air preheater; the flue gas outlet at the bottom of the air preheater is connected to the smoke collecting chamber, and a smoke exhaust port is arranged on one side of the smoke collecting chamber;

A cold air inlet and a hot air outlet are respectively arranged on both sides of the air preheater; the hot air outlet is connected to the air inlet of the burner in the boiler main unit through an air duct.

Preferably, steel belts are spirally wound on the straight tube sections of the vertical serpentine heat exchange tubes.

Preferably, the inclination angle of the straight tube section of the vertical serpentine heat exchange tube is 3° to 5°.

Preferably, the other end of the steam outlet pipe seat is connected to the inlet of an external steam-water separator; and the bottom water outlet pipe of the steam-water separator is connected to the interior of the steam drum.

Preferably, the air preheater is located at the bottom of the waste heat boiler; and the smoke collecting chamber is located at the bottom of the air preheater.

Preferably, horizontal tube sheets are fixedly arranged at the top and bottom of the air preheater respectively; both ends of the vertical heat exchange tubes pass through the corresponding horizontal tube sheets and are fixedly connected to the horizontal tube sheets; the horizontal tube sheet located at the lower part is connected to the external frame, and the horizontal tube sheet located at the upper part is connected to the external frame through an expansion joint.

Preferably, a spoiler strip in the shape of a spring wire is arranged in the vertical heat exchange tube; the spoiler strip extends from the upper end to the bottom end of the vertical heat exchange tube.

Preferably, the main boiler is arranged horizontally, a burner is arranged at the front of the main boiler, and a flue gas outlet is arranged at the rear of the main boiler;

A spiral inner coil and a spiral outer coil are arranged inside the boiler main unit; the spiral inner coil forms a furnace, the spiral inner coil and the spiral outer coil form a first convection channel, and the spiral outer coil and the shell of the boiler main unit form a second convection channel.

Preferably, refractory mud is coated on the front inner wall of the boiler main unit, and multiple insulation layers are arranged on the front wall surface of the boiler main unit.

Preferably, a smoke-isolating wall is arranged at the rear of the main boiler unit; the smoke-isolating wall and the rear end cover of the main boiler unit form a rear smoke chamber, and the rear smoke chamber is connected to the second convection channel and the smoke outlet.

The beneficial effects of the present invention are:

(1) The present invention can effectively reduce the final exhaust gas temperature of the boiler by arranging a two-stage energy-saving device of a waste heat boiler and an air preheater at the tail end of the boiler main engine to recycle the waste heat in the flue gas at the flue gas outlet of the boiler main engine; at the same time, the setting of the waste heat boiler of the first-stage energy-saving device can provide users with part of the steam used for production and life, greatly improving the thermal efficiency of the boiler; the air preheater of the second-stage energy-saving device can further reduce the final exhaust gas temperature and increase the temperature of the cold air entering the furnace, so that the final exhaust gas temperature of the boiler is not higher than 100°C, further improving the thermal efficiency of the boiler.

(2) In the present invention, a plurality of rows of vertical serpentine heat exchange tubes are arranged in the waste heat boiler, and the straight tube sections of the vertical serpentine heat exchange tubes are inclined upward along the flow direction of the medium in the vertical serpentine heat exchange tubes. At the same time, steel belts are spirally wound on the straight tube sections of the vertical serpentine heat exchange tubes. The inclined tube bundle arrangement allows the steam in the steam-water mixture generated in the vertical serpentine heat exchange tubes to quickly enter the upper steam drum, thereby preventing a large amount of steam from accumulating in the vertical serpentine heat exchange tubes during operation of the boiler, thereby affecting the safe operation of the boiler. The arrangement of the steel belts can increase the heating surface and improve the heat transfer efficiency.

(3) The provision of spoiler strips in the vertical heat exchange tubes in the air preheater of the present invention can change the flow state of the flue gas in the tubes, strengthen the heat exchange process, and make the heat exchange more sufficient.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings in the specification, which constitute a part of the present application, are used to provide further understanding of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute improper limitations on the present application.

FIG1 is a schematic structural diagram of an energy-saving and environmentally friendly thermal oil boiler according to the present invention;

FIG2 is a schematic diagram of the structure of the boiler host in the present invention;

FIG3 is a schematic diagram of the structure of an air preheater in the present invention;

in,

1- boiler main engine, 11- flue gas outlet, 12- burner, 13- spiral inner coil, 14- spiral outer coil, 15- furnace, 16- first convection channel, 17- second convection channel, 18- fixed distance pipe, 19- refractory mud, 110- smoke partition wall, 111- rear smoke chamber, 112- explosion-proof door;

2-waste heat boiler, 21-vertical body, 22-vertical serpentine heat exchange tube, 221-steel belt, 23-steam drum, 231-centralized downcomer, 232-steam outlet pipe seat, 24-steam-water separator;

3-air preheater, 31-external frame, 32-vertical heat exchange tube, 33-cold air inlet, 34-hot air outlet, 35-air duct, 36-horizontal tube sheet, 37-spoiler strip, 38-expansion joint;

4- Flue gas duct;

5-smoke collecting chamber, 51-smoke exhaust port;

Smoke flow direction.

DETAILED DESCRIPTION

It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and/or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and/or combinations thereof.

In the present invention, the directions or positional relationships indicated by terms such as "upper", "lower", "bottom", "top", etc. are based on the directions or positional relationships shown in the accompanying drawings. They are relational words determined only for the convenience of describing the structural relationships of the various parts or elements of the present invention. They do not specifically refer to any part or element in the present invention and cannot be understood as limitations on the present invention.

In the present invention, terms such as "connected" and "connection" should be understood in a broad sense, indicating that the connection can be fixed, integral or detachable; it can be directly connected or indirectly connected through an intermediate medium. Relevant scientific research or technical personnel in this field can determine the specific meaning of the above terms in the present invention according to specific circumstances, and they should not be understood as limiting the present invention.

The present invention is further described below in conjunction with the accompanying drawings and embodiments.

Embodiment 1:

As shown in FIG1 , an energy-saving and environmentally friendly thermal oil boiler includes a boiler main unit 1, a waste heat boiler 2, and an air preheater 3;

The waste heat boiler 2 includes a vertical body 21; a plurality of rows of vertical serpentine heat exchange tubes 22 are arranged in the vertical body 21, and the straight tube sections of the vertical serpentine heat exchange tubes 22 are inclined upward along the flow direction of the medium in the vertical serpentine heat exchange tubes 22. The inclined tube bundle arrangement can make the steam in the steam-water mixture generated in the vertical serpentine heat exchange tubes 22 quickly enter the upper steam drum 23, thereby preventing a large amount of steam from accumulating in the vertical serpentine heat exchange tubes 22 during the operation of the boiler, thereby affecting the safe operation of the boiler; the upper outlet of the vertical serpentine heat exchange tubes 22 The steam drum 23 is connected to the side wall of the vertical body 21 through a bracket; a centralized downcomer 231 is arranged at the bottom of the steam drum 23, and the centralized downcomer 231 is connected to the lower inlet of the vertical serpentine heat exchange tube 22 through a lower water header; a steam outlet pipe seat 232 is arranged at the top of the steam drum 23, and the steam outlet pipe seat 232 is connected to the steam-water separator 24, so as to finally provide high-quality dry saturated steam to the user; a water inlet pipe is arranged on the side wall of the steam drum 23, and medium water is provided to the vertical serpentine heat exchange tube 22 through the water inlet pipe;

The waste heat boiler 2 of the present application is a first-level energy-saving device, with flue gas flowing outside the vertical serpentine heat exchange tube 22 and medium water flowing inside the vertical serpentine heat exchange tube 22; the water circulation inside the vertical serpentine heat exchange tube 22 is a natural circulation method, and the flue gas flushes the heating surface from top to bottom outside the vertical serpentine heat exchange tube 22. After the steam-water mixture in the vertical serpentine heat exchange tube 22 is heated, its density decreases and it flows upward and enters the steam drum 23. The steam therein is discharged along the steam outlet pipe seat 232, and the water therein flows downward along the concentrated downcomer 231 and enters the bottom inlet of the vertical serpentine heat exchange tube 22 again. The pressure difference generated by the density difference between cold water and hot water is used to make the water in the vertical serpentine heat exchange tube 22 circulate naturally.

As shown in FIG3 , the air preheater 3 includes an external frame 31 , and a plurality of vertical heat exchange tubes 32 are arranged inside the external frame 31 ;

The flue gas outlet 11 of the main boiler 1 is connected to the flue gas inlet at the top of the waste heat boiler 2 through the flue gas duct 4; the flue gas outlet at the bottom of the waste heat boiler 2 is connected to the vertical heat exchange tube 32 in the air preheater 3; the flue gas outlet at the bottom of the air preheater 3 is connected to the smoke collecting chamber 5, and a smoke exhaust port 51 is provided on one side of the smoke collecting chamber 5;

The air preheater 3 is provided with a cold air inlet 33 and a hot air outlet 34 on both sides thereof; the hot air outlet 34 is connected to the air inlet of the burner in the boiler main unit 1 through an air duct 35; specifically, the cold air enters the cold air inlet 33 through the blower;

In the present application, the air preheater 3 is a two-stage energy-saving device. The flue gas in the air preheater 3 flushes longitudinally in the vertical heat exchange tube 32, and the air flushes transversely outside the vertical heat exchange tube 32 to complete the heat exchange. The air heated by the flue gas is supplied to the burner, saving fuel. At the same time, in the present application, the flue gas passes through the waste heat boiler 2 and then enters the air preheater 3 to heat the air. The waste heat boiler 2 consumes the flue gas temperature so that the subsequent flue gas temperature entering the air preheater 3 is not higher than 180°C, so that the air temperature entering the burner in the boiler main unit 1 is not higher than 100°C, thereby preventing the generation of nitrogen oxides when the burner is running, achieving low-nitrogen combustion, reducing nitrogen oxide emissions, and meeting environmental protection requirements.

Therefore, the present application arranges a two-stage energy-saving device of a waste heat boiler 2 and an air preheater 3 at the tail end of the boiler main unit 1 to recycle the waste heat in the flue gas at the flue gas outlet of the boiler main unit, thereby effectively reducing the final exhaust temperature of the boiler, so that the final exhaust temperature of the boiler (the exhaust temperature of the exhaust port 51 on the smoke collecting chamber 5) is not higher than 100°C. At the same time, the arrangement of the first-stage energy-saving device waste heat boiler 2 can provide users with part of the steam used for production and life, greatly improving the thermal efficiency of the boiler.

Preferably, the straight tube sections of the vertical serpentine heat exchange tubes 22 are all spirally wound with steel belts 221 to increase the heating surface and improve the heat transfer efficiency.

Preferably, the inclination angle of the straight tube section of the vertical serpentine heat exchange tube 22 is 3° to 5° to prevent steam-water stratification in the tube and affect the safe operation of the boiler.

Preferably, the other end of the steam outlet pipe seat 232 is connected to the inlet of an external steam-water separator 24; an external steam-water separator 24 is provided outside the steam drum 23 to effectively separate droplets in the steam and improve the steam quality.

Preferably, the bottom water outlet pipe of the steam-water separator 24 is connected to the interior of the steam drum 23; and the hot water separated by the steam-water separator 24 is recovered.

Preferably, the air preheater 3 is located at the bottom of the waste heat boiler 2; the smoke collecting chamber 5 is located at the bottom of the air preheater 3; that is, the waste heat boiler 2, the air preheater 3, and the smoke collecting chamber 5 are in a vertical structure from top to bottom, occupying a small area and saving space.

Embodiment 2:

On the basis of Example 1, as shown in Figure 3, horizontal tube sheets 36 are fixedly arranged at the top and bottom of the air preheater 3 respectively; both ends of the vertical heat exchange tube 32 pass through the corresponding horizontal tube sheets 36 and are fixedly connected to the horizontal tube sheets 36; the horizontal tube sheet 36 located at the lower part is connected to the external frame 31, and the horizontal tube sheet 36 located at the upper part is connected to the external frame 31 through an expansion joint 38.

Among them, the top of the vertical heat exchange tube 32 is connected to the flue gas outlet of the waste heat boiler 2, and the bottom of the vertical heat exchange tube 32 is connected to the smoke collecting chamber 5; the setting of the horizontal tube plate 36 is used to install the vertical heat exchange tube 32 on the one hand, and on the other hand, it also separates the air circulation cavity from the smoke circulation cavity in the vertical heat exchange tube 32.

Preferably, a spoiler strip 37 in the shape of a spring wire is disposed in the vertical heat exchange tube 32 ; the spoiler strip 37 extends from the upper end to the bottom end of the vertical heat exchange tube 32 .

In the present application, the spoiler strip 37 is easy to install, and the worker can directly insert the formed spoiler strip 37 into the vertical heat exchange tube 32 so that the spoiler strip 37 is clamped in the vertical heat exchange tube 32; the setting of the spoiler strip 37 in the vertical heat exchange tube 32 changes the flow state of the flue gas in the tube, strengthens the heat exchange process, and makes the heat exchange more sufficient.

Embodiment 3:

On the basis of Example 1 or Example 2, as shown in FIG2 , the main boiler unit 1 is arranged horizontally, a burner 12 is arranged at the front of the main boiler unit 1, and a flue gas outlet 11 is arranged at the rear of the main boiler unit 1;

A spiral inner coil 13 and a spiral outer coil 14 are arranged inside the boiler main unit 1; the spiral inner coil 13 forms a furnace 15, a first convection channel 16 is formed between the spiral inner coil 13 and the spiral outer coil 14, and a second convection channel 17 is formed between the spiral outer coil 14 and the shell of the boiler main unit 1; specifically, the inlets of the spiral inner coil 13 and the spiral outer coil 14 are respectively connected to the external oil inlet pipe, and the outlets of the spiral inner coil 13 and the spiral outer coil 14 are respectively connected to the external oil outlet pipe; in addition, the fixing method of the spiral inner coil 13 and the spiral outer coil 14 inside the boiler main unit 1 can be achieved by adopting the existing technology, and they are usually fixed on the shell of the boiler main unit 1 through a distance pipe 18.

In the present application, the boiler main unit 1 adopts a spiral coil as the main heating surface to form a three-pass structure. The fuel is burned in a furnace 15 surrounded by a spiral inner coil 13. The high-temperature flue gas at the outlet of the furnace 15 first flows through a first convection channel 16 composed of a spiral inner coil 13 and a spiral outer coil 14, and then flows through a second convection channel 17 composed of a spiral outer coil 14 and the shell of the boiler main unit 1, and enters the waste heat boiler 2 through the flue gas outlet 11.

Preferably, the front inner wall of the boiler main unit 1 is coated with refractory mud 19, and multiple insulation layers are arranged on the front wall surface of the boiler main unit 1 to reduce heat loss.

Preferably, a smoke-isolating wall 110 is provided at the rear of the boiler main unit 1 ; the smoke-isolating wall 110 and the rear end cover of the boiler main unit 1 form a rear smoke chamber 111 , and the rear smoke chamber 111 is connected to the second convection channel 17 and the smoke outlet 11 .

The setting of the smoke partition wall 110, on the one hand, promotes the flue gas to circulate along the furnace 15, the first convection channel 16, and the second convection channel 17 in order to achieve sufficient heat exchange with the heat transfer oil in the coil; on the other hand, it reduces the surface temperature of the rear smoke box and reduces the heat dissipation loss of the boiler.

Preferably, an explosion-proof door 112 is provided on the rear end cover of the boiler main unit 1 to ensure safe operation of the boiler.

Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not a limitation of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the protection scope of the present invention.

Claims (8)

1. An energy-saving environment-friendly heat conduction oil boiler is characterized by comprising a boiler main machine, a waste heat boiler and an air preheater;

The waste heat boiler comprises a vertical body; a plurality of rows of vertical serpentine heat exchange tubes are arranged in the vertical body, and straight tube sections of the vertical serpentine heat exchange tubes are in an inclined upward state along the flow direction of medium in the vertical serpentine heat exchange tubes; the upper outlet of the vertical serpentine heat exchange tube is communicated with the steam drum; the bottom of the steam drum is provided with a concentrated descending pipe which is communicated with the lower inlet of the vertical serpentine heat exchange pipe through a lower water header, the top of the steam drum is provided with a steam outlet pipe seat, and the side wall of the steam drum is provided with a water inlet pipe;

the air preheater comprises an outer frame, wherein a plurality of vertical heat exchange tubes are arranged inside the outer frame;

the flue gas outlet of the boiler main machine is connected with the flue gas inlet at the top of the waste heat boiler through a flue gas pipeline; the flue gas outlet at the bottom of the waste heat boiler is communicated with a vertical heat exchange tube in the air preheater; the flue gas outlet at the bottom of the air preheater is communicated with a flue gas collecting cavity, and a flue gas outlet is arranged at one side of the flue gas collecting cavity;

a cold air inlet and a hot air outlet are respectively arranged on two sides of the air preheater; the hot air outlet is communicated with an air inlet of a burner in the main machine of the boiler through an air pipeline;

steel strips are spirally wound on straight pipe sections of the vertical serpentine heat exchange pipes;

the inclination angle of the straight pipe section of the vertical type S-shaped heat exchange pipe is 3-5 degrees.

2. The energy-saving and environment-friendly heat conducting oil boiler according to claim 1, wherein the other end of the steam outlet tube seat is connected with an inlet of an external steam-water separator; the bottom water outlet pipe of the steam-water separator is communicated with the inside of the steam drum.

3. The energy-saving and environment-friendly heat conducting oil boiler according to claim 1, wherein the air preheater is positioned at the bottom of the waste heat boiler; the smoke collecting cavity is positioned at the bottom of the air preheater.

4. The energy-saving and environment-friendly heat conducting oil boiler according to claim 1, wherein the top and the bottom of the air preheater are fixedly provided with horizontal tube plates respectively; the two ends of the vertical heat exchange tube penetrate through the corresponding horizontal tube plates and are fixedly connected with the horizontal tube plates; the horizontal tube plate at the lower part is connected with the outer frame, and the horizontal tube plate at the upper part is connected with the outer frame through an expansion joint.

5. The energy-saving and environment-friendly heat transfer oil boiler according to claim 1, wherein turbulence strips in the shape of spring wires are arranged in the vertical heat exchange tubes; the turbulence bars extend from the upper end to the bottom end of the vertical heat exchange tube.

6. The energy-saving and environment-friendly heat conducting oil boiler according to claim 1, wherein the boiler main engine is arranged horizontally, the front part of the boiler main engine is provided with a burner, and the tail part of the boiler main engine is provided with a smoke outlet;

A spiral inner coil and a spiral outer coil are arranged in the boiler main machine; the spiral inner coil surrounds a hearth, a first convection channel is surrounded between the spiral inner coil and the spiral outer coil, and a second convection channel is surrounded by the spiral outer coil and a shell of the boiler host.

7. The energy-saving and environment-friendly heat conducting oil boiler according to claim 6, wherein the inner wall of the front part of the main machine of the boiler is coated with fire clay, and a plurality of heat preservation layers are arranged on the wall surface of the front part of the main machine of the boiler.

8. The energy-saving and environment-friendly heat conducting oil boiler according to claim 6, wherein a smoke-separating wall is arranged at the tail part of the main machine of the boiler; the smoke-separating wall and the rear end cover of the boiler main machine form a rear smoke chamber, and the rear smoke chamber is communicated with the second convection channel and the smoke outlet.