WO2007102793A1

WO2007102793A1 - Recovery boiler

Info

Publication number: WO2007102793A1
Application number: PCT/UA2007/000012
Authority: WO
Inventors: Yevgeniy Alekseevich Danilin; Aleksandr Aleksandrovich Lobov
Original assignee: Yevgeniy Alekseevich Danilin; Aleksandr Aleksandrovich Lobov
Priority date: 2006-03-07
Filing date: 2007-02-19
Publication date: 2007-09-13
Also published as: RU2365818C2; UA82389C2; RU2006144504A

Abstract

The inventive recovery boiler is directed at disinfecting and recycling heat of smoke fumes and can be used in the coke-chemical, chemical and other industries. The recovery boiler comprises pipes for supplying flue gases (11, 12), a flue gas removing pipe (2), a reactor (3) provided with cyclone combustion chambers (41, 42) each of which comprises a burner unit (5) and to which the pipes for supplying flue gases (11, 12) are tangentially connected. Said recovery boiler also is also provided with a heat recycling system (6) which comprises heat-exchanging surfaces (7) and is connected to the reactor (3) and to the flue gas removing pipe (2). The recovery boiler comprises a system (8) which is used for enriching flue gases with fuel and air and is connected to the pipes for supplying flue gases (11, 12). The reactor is provided with an after-burning chamber (9) which is connected to the cyclone combustion chambers (41, 42) and forms therewith a reactor working space. Said invention makes it possible to increase the degree of removal of impurities from flue gases, to improve the reliability of the recovery boiler operation and the recycling efficiency of heat of the flue gases exhausted from fuel combustion plants.

Description

WATER BOILER

FIELD OF TECHNOLOGY

The recovery boiler is designed for the neutralization and utilization of flue gas heat and can be used in the coke, metallurgical, chemical and other industries.

BACKGROUND OF THE INVENTION

A known recovery boiler containing a flue gas supply pipe, a flue gas pipe, a reactor including a burner, a heat recovery system including heat exchanging surfaces of heat exchangers (see USSR Authors Certificate Ne 1572145, IPC F22B 1/18, publ. 27.12. 95 rub.).

A disadvantage of the known recovery boiler is the low degree of purification of flue gases, which leads to the sticking of resinous and carbonaceous impurities on the heat exchange surfaces of the heat exchangers. The well-known recovery boiler does not allow to completely burn out the impurities contained in the flue gases, which reduces the efficiency of the heat exchange surfaces.

A known recovery boiler, selected as a prototype, comprising a flue gas supply pipe, a flue gas pipe, a reactor equipped with a cyclone combustion chamber including a burner, into which a flue gas pipe is connected tangentially, a heat recovery system including heat exchange surfaces and a connected with a reactor and a flue gas outlet pipe, (see Aut. USSR Certificate Ne 1188454, IPC F23G 7/06, publ. 30.10.85r.). The heat recovery system contains a radiation heat exchanger that is adjacent to the combustion chamber, as well as a convective heat exchanger.

A disadvantage of the known recovery boiler is the low degree of purification of flue gases, due to the fact that the radiation heat exchanger adjacent to the combustion chamber, which leads to a sharp drop in temperature at the outlet of the reactor, and also leads to intense sticking of resinous and carbon impurities on the heat transfer surfaces of radiation and convective heat exchangers. Another drawback of the recovery boiler is the low efficiency of mixing the combustible components contained in the flue gas with air and fuel, which are fed through the burner to the reactor, which, in turn, leads to an unstable temperature field and to incomplete combustion of impurities contained in the flue gas gases. The presence of unburned impurities in flue gases leads to an insufficient degree of neutralization of flue gases, on the one hand, and, on the other hand, to contamination of the heat exchange surfaces of radiation and convective heat exchangers with resins and carbon particles, which form deposits on the heat exchange surfaces of heat exchangers, which leads to a low degree of heat recovery and reduce the reliability of the recovery boiler.

Intensive formation of deposits on heat-exchange surfaces leads to their rapid pollution, which reduces the reliability of the recovery boiler and the efficiency of heat recovery (COP) of the recovery boiler.

SUMMARY OF THE INVENTION

The objective of the present invention is to provide a recovery boiler with a high degree of purification of flue gases from impurities, as well as improving the reliability of the recovery boiler and the efficiency of heat recovery of flue gases from fuel-burning units, for example, coke ovens.

The problem is solved in that in the known recovery boiler containing a flue gas supply pipe, a flue gas pipe, a reactor equipped with a cyclone combustion chamber including a burner device into which a flue gas pipe is connected tangentially, a heat recovery system including heat exchange surfaces and connected to the reactor and the flue gas outlet pipe, according to the claimed invention, the recovery boiler is equipped with a system the flue gas enrichment with fuel and air, which is connected to the flue gas supply pipe, the reactor further comprises at least one cyclone combustion chamber and is equipped with a afterburner associated with the cyclone combustion chambers and forming together with them the working volume of the reactor.

In a particular embodiment of the recovery boiler, a diaphragm is installed at the outlet of the reactor, the outlet opening of which connects the reactor to the heat recovery system, while the area of the outlet of the diaphragm is determined by the following relationship:

0.44 <Si / S ₂ ≤0.9, (1) where:

5 ₁ - the area of the outlet of the diaphragm, m ² ;

5 ₂ - the area of the base of the afterburner, m ² .

In a particular embodiment of the waste heat boiler, the ratio of the volume of the afterburner to the working volume of the reactor is determined by the following relationship:

О ^ ЗWi / Vg≤O. ^β δ, (2) where:

Vi is the volume of the afterburner, m ³ ; V ₂ - the working volume of the reactor, m ³ .

In a particular embodiment of the recovery boiler, at least one additional flue gas supply pipe tangentially adjoins each cyclone combustion chamber.

In a particular embodiment of the waste heat boiler, a damper is installed in the flue gas supply pipe.

In a particular embodiment of the recovery boiler, the afterburner contains at least one protrusion located on the inner surface of the afterburner and having the following dimensions:

0.05d <a <0.5d, (3) 0.5d <b≤25d, (4) 0 ° <α <90 °, (5) where: a - protrusion height, m; b is the length of the protrusion, m; d is the diameter of the cyclone combustion chamber, m; α is the angle of inclination of the protrusion to the base of the afterburner, deg.

In a particular embodiment of the recovery boiler, a grate is installed at the outlet of the reactor.

In a particular embodiment of the recovery boiler, the afterburner and cyclone combustion chambers are made of refractory and heat-insulating materials.

In a private embodiment of the recovery boiler, an additional heat recovery system is installed in the flue gas outlet pipe, including heat exchange surfaces.

In a particular embodiment of the waste heat boiler, a forced flue gas exhaust system adjacent to a flue gas exhaust device adjoins the flue gas outlet pipe.

In a particular embodiment of the waste heat boiler, a turbulizing grid is installed in the flue gas supply pipe.

In a particular embodiment of the recovery boiler, the burner device is axially positioned in the cyclone combustion chamber.

In a particular embodiment of the recovery boiler, each cyclone combustion chamber is equipped with an additional diaphragm, the opening of which connects the cyclone combustion chamber to the afterburner, and the opening area is determined by the following relationship:

0.44 <S3 / S ₄ <0.9, (6) where:

S ₃ - the area of the hole, m ² ; S ₄ - the base area of the cyclone combustion chamber, m ² . The proposed technical solution allows to increase the degree of purification of flue gases from impurities, as well as the reliability of the waste heat boiler by introducing an additional system for enriching flue gases with fuel and air before supplying flue gases to the reactor. This contributes to effective mixture formation and leads to an intensification of the combustion process in the working volume of the reactor, which ensures the efficient purification of flue gases from impurities. Equipping the reactor with the afterburner allows increasing the residence time of the flue gases in the working volume of the reactor, and also helps to stabilize the temperature field in the working volume of the reactor, in which the combustion process and the cleaning of flue gases from impurities occur. The introduction of an additional cyclone combustion chamber into the reactor leads to the formation of opposing flue gas vortex flows in the afterburner chamber, which exit from the cyclone combustion chambers, which increases the efficiency of flue gas neutralization due to intensive mixing of flue gases with fuel and air, as well as due to efficient afterburning resinous and carbon impurities in the working volume of the reactor. This reduces the contamination of the heat exchange surfaces of the heat recovery system with resins, carbon particles that form deposits on the heat exchange surfaces, and increases the reliability of the recovery boiler and the efficiency of heat recovery, as well as reduces the “sensitivity” of the recovery boiler to polluted flue gases, which have a significant content resinous and carbon impurities.

BRIEF DESCRIPTION OF THE FIGURES

The inventive waste heat boiler is shown in the following drawings:

FIG. 1 is a general view of a waste heat boiler;

FIG. 2 is a front view of FIG. one ; FIG. 3 is an embodiment of a waste heat boiler reactor;

FIG. 4 is an embodiment of a waste heat boiler reactor;

FIG. 5 is an embodiment of a waste heat boiler reactor;

FIG. 6 is an embodiment of a waste heat boiler reactor;

FIG. 7 is a section AA of FIG. 2; FIG. 8 is a section BB of FIG. 2; FIG. 9 is an embodiment of a waste heat boiler with two cyclone combustion chambers;

FIG. 10 is an embodiment of a waste heat boiler with four cyclone combustion chambers.

DETAILED DESCRIPTION OF THE INVENTION

The recovery boiler contains flue gas supply pipes 1-ι, "b, the flue gas discharge pipe 2, reactor 3 provided with cyclone combustion chambers 4-ι, A ₂ , each of which includes an axially mounted burner device 5. The recovery boiler contains a system heat recovery 6, including heat exchange surfaces 7 and connected to the reactor 3 and the flue gas exhaust pipe 2.

The recovery boiler is also equipped with a system for enriching 8 flue gases with fuel and air, which is connected to the flue gas inlets 1i, 1 ₂ . The reactor 3 is equipped with a afterburner 9 adjacent to the cyclone combustion chambers 4i, 4g and together with them forming the working volume of the reactor 3. At the outlet of the reactor 3 there is a diaphragm 10 in which an outlet 11 is made which connects the reactor 3 to the heat recovery system 6 (see Fig. 1, 2).

In the embodiments of the recovery boiler below, which are shown in FIG. 3-6, 9, 10, private embodiments of a waste heat boiler are presented.

The area of the outlet 11 of the diaphragm 10 is determined in accordance with the dependence (1).

The volume of the afterburner 9 is determined in accordance with the dependence (2).

In each flue gas supply pipe 1 h, 1 g, a shutter 12 is installed. At the outlet of the reactor 3, a grill 14 is installed. The inner surface of the afterburner 9 and combustion chambers 4i, 4g are made of refractory and heat-insulating materials, namely fireclay bricks, refractory clay, etc.

In the flue gas exhaust pipe 2, an additional heat recovery system 15 is installed, including heat exchange surfaces 7.

The flue gas exhaust pipe 2 is adjacent to the forced flue gas exhaust system 16, including a draft device.

In each branch pipe for supplying flue gases 1 i, 1 g, a turbulizing grid 17 is installed.

Each cyclone combustion chamber 4i, 4g has an additional diaphragm 18, an opening 19 of which connects the cyclone combustion chamber 4i, 4 ₂ with the afterburner 9.

The area of the hole 19 of each cyclone combustion chamber 4i, 4 ₂ is determined in accordance with the dependence (6).

In FIG. 3 shows an embodiment of a reactor 3 in which protrusions 13i are arranged on the inner surface of the afterburner 9 parallel to the base of the afterburner 9.

In FIG. 4 shows an embodiment of a reactor 3 in which protrusions 13 ₂ are arranged perpendicular to the base of the afterburner 9 on the inner surface of the afterburner 9.

In FIG. 5 shows an embodiment of a reactor 3 in which protrusions 13 ₃ are placed on the inner surface of the afterburner 9 at an angle α to the base of the afterburner 9.

In FIG. 6 shows an embodiment of a reactor 3 in which protrusions 13h, 13g are placed on the inner surface of the afterburner 9. In FIG. Figure 9 shows an embodiment of a waste heat boiler with two cyclonic combustion chambers 4ι, 4 ₂ , to which the flue gas supply pipes 1 i, 1 _{2 are} tangentially connected, and additional flue gas supply pipes 1 c, 1 ₂ -ι, respectively, are connected. Each flue gas supply pipe 1 i, 1 c, 1 ₂ , 1 ₂ i, is adjoined by a flue gas enrichment system with fuel and air, and also in each flue gas supply pipe 1 i, 1 c, 1 g, 121, a turbulizing grid 17 and damper 12.

In FIG. 10 shows an embodiment of a waste heat boiler with four cyclone combustion chambers 4i, 4 ₂ , 4z, 4 ₄ , to which four flue gas supply pipes 1i, 1 ₂ , 1z, 1 _{4 are} connected, respectively.

The waste heat boiler operates as follows.

Flue gases leaving the fuel-burning unit (not shown in the drawings) enter the flue gas supply pipes 1 i, 1 ₂ , each of which has a damper 12 for controlling the supply of flue gases to the cyclone combustion chambers 4i, 4 _{2 of the} reactor 3 of the boiler utilizer. In the nozzles for supplying flue gases 1 i, 1 _{2, the} flue gases are enriched in fuel and air using the enrichment system 8, which is adjacent to the nozzles for supplying flue gases 1i, 1 ₂ . In each flue gas supply pipe 1i, 1 ₂ a turbulizing grid 17 is installed for turbulizing the flue gas flow entering the cyclone combustion chambers 4i, 4 ₂ . Turbulization of flue gases enriched with air and fuel contributes to their better mixing.

The introduction of flue gases into the cyclone combustion chamber 4i, 4 ₂ by means of the tangentially connected nozzles 1i, 1 ₂ provides the activation of mixing of flue gases in the cyclone combustion chambers 4i, 4 ₂ .

The axial arrangement of the burner device 5, to which air and fuel is supplied in each cyclone combustion chamber 4i, 4 ₂ , ensures an increase in the length of the flame in the working volume of the reactor 3 and helps to stabilize the temperature field in the reactor 3. The flow of flue gases from the cyclone combustion chamber 4-ι moves to the afterburner 9, in which it meets another flue gas stream exiting the cyclone chamber combustion 4 ₂ . This provides intensive mixing of the flue gases and helps to reduce the concentration of nitrogen oxides (NO _x ) and carbon monoxide (CO) in the flue gases. The ratio (Vi / V ₂ ) of the volume of the afterburner 9 to the total volume of the reactor 3, selected in accordance with dependence (2), allows to optimize the combustion process, the residence time of the flue gases in the working volume of the reactor 3 and improves the efficiency of cleaning flue gases from impurities.

The presence of a diaphragm 10 in the reactor 3, as well as the presence of projections 13i, 13g in the afterburner 9 and the presence of an additional diaphragm 18 in each cyclone combustion chamber 4i, 4 ₂ , in which the opening 19 is made, prevents the passage of tar and carbon particles along the walls of the afterburner 9 into the heat recovery system 6 through the outlet 11 of the diaphragm 10.

The grating 14 installed at the outlet of the reactor 3 contributes to the turbulization of the flue gas flow, which ensures efficient heat transfer, and also helps to reduce the concentration of nitrogen oxides (NO _x ). After the reactor 3, the flue gas enters the heat recovery system 6. In the heat recovery system b and in the additional heat recovery system 15, heat exchange surfaces 7 are installed, for example: superheaters, evaporators, economizers, etc., which make it possible to efficiently utilize the heat of the flue gases. After the heat recovery system 6, the flue gas enters the flue gas exhaust pipe 2, in which an additional heat recovery system 15 is installed, which is intended for additional heat recovery of the flue gas. Then the flue gases are discharged into the environment through a forced exhaust system 16.

In a particular embodiment of the recovery boiler, two cyclone combustion chambers 4i, 4 ₂ (see Fig. 9) are installed in the reactor 3, to which two flue gas supply pipes 1 i, 1 ₂ , as well as two additional flue gas supply pipes are tangentially connected 1 q, 1 ₂ i, respectively. The approach to the cyclone combustion chambers 4 |, 4 ₂ additional nozzles for supplying flue gases 1c, 1 ₂ i provides effective mixing flue gases enriched with air and fuel in cyclone combustion chambers 4i, 4 ₂ .

In a particular embodiment of the waste heat boiler (see FIG. 10), four cyclone combustion chambers 4i, 4 ₂ , 4 ₃ , 4_t are installed in reactor 3 5, to which four flue gas supply pipes I ₁ , 1 ₂ , 1z, 1 are connected ₄ , respectively. This ensures the efficient operation of the recovery boiler by increasing the stabilization of the temperature field in the working volume of the reactor 3. 0

Tests were carried out on the complex “Coconut furnace - waste heat boiler which is installed in JSC“ 3aPozhkoks ”. In this case, the flue gases from the coke oven were fed to a waste heat boiler operating at a temperature of 1095 ⁰ C. The results of tests with various options for performing 5 waste heat boiler are shown in tables 1, 2.

Table 1

- table 1 shows the following conventions: a-ι, a ₂ - the height of the protrusions 13i, 13 ₂ , respectively, m; bi, b ₂ - the length of the protrusions 13i, 13 _2l, respectively, m; he, Ct ₂ - the angle of inclination of the protrusions 13 ^ 13 ₂ to the base of the afterburner 9, respectively, deg.

Table 2

Claims

CLAIM

1. A waste heat boiler comprising a flue gas supply pipe, a flue gas pipe, a reactor equipped with a cyclone combustion chamber including a burner device into which a flue gas pipe is connected tangentially, a heat recovery system including heat exchange surfaces and connected to the reactor and the pipe flue gas extraction, characterized in that the waste heat boiler is equipped with a flue gas enrichment system with fuel and air, which is connected with a flue gas supply pipe, the reactor is additionally contains at least one cyclone combustion chamber and is equipped with an afterburner associated with the cyclone combustion chambers and forming together with them the working volume of the reactor.

2. The recovery boiler according to claim 1, characterized in that a diaphragm is installed at the outlet of the reactor, the outlet opening of which connects the reactor to the heat recovery system, while the area of the outlet of the diaphragm is determined by the following relationship: 0.44 <Si / S ₂ ≤ 0.9 where:

Si is the area of the outlet of the diaphragm, m ² ; Sg - base area of the afterburner, m ² .

3. The recovery boiler according to claim 1, characterized in that the ratio of the volume of the afterburner to the working volume of the reactor is determined by the following relationship:

0.43 <Vi / V ₂ <0.85 where: Vi is the volume of the afterburner, m ³ ;

Vg is the working volume of the reactor, m ³ .

4. The recovery boiler according to claim 1, characterized in that at least one additional flue gas supply pipe is tangentially adjacent to each cyclone combustion chamber.

5. The waste heat boiler according to claim 1, characterized in that a damper is installed in the flue gas supply pipe.

6. The recovery boiler according to claim 1, characterized in that the afterburner contains at least one protrusion located on the inner wall of the afterburner and having the following dimensions:

0.05d <a <0.5d 0.5d <b≤25d 0 ° <α <90 °

where: a is the height of the protrusion, m; b is the length of the protrusion, m; d is the diameter of the cyclone combustion chamber, m; α is the angle of inclination of the protrusion to the base of the afterburner, deg.

7. The recovery boiler according to claim 1, characterized in that a grate is installed at the outlet of the reactor.

8. The recovery boiler according to claim 1, characterized in that the afterburner and the cyclone combustion chambers are made of refractory and heat-insulating materials.

9. The recovery boiler according to claim 1, characterized in that an additional heat recovery system including heat exchange surfaces is installed in the flue gas outlet pipe.

10. The waste heat boiler according to claim 1, characterized in that the forced flue gas exhaust system adjoins the flue gas outlet pipe, including a draft device.

11. The waste heat boiler according to claim 1, characterized in that a turbulizing grate is installed in the flue gas supply pipe.

12. The recovery boiler according to claim 1, characterized in that the burner device is axially located in the cyclone combustion chamber.

13. The recovery boiler according to claim 1, characterized in that each cyclone combustion chamber is equipped with an additional diaphragm, the opening of which connects the cyclone combustion chamber to the afterburner, and the opening area is determined by the following relationship:

0.44 <Sz / S ₄ <0.9 where: Sz - hole area, m ² ;

S ₄ - the base area of the cyclone combustion chamber, m ² .