CN112664953A - Circulating fluidized bed incineration boiler for burning solid waste - Google Patents
Circulating fluidized bed incineration boiler for burning solid waste Download PDFInfo
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- CN112664953A CN112664953A CN201911334425.5A CN201911334425A CN112664953A CN 112664953 A CN112664953 A CN 112664953A CN 201911334425 A CN201911334425 A CN 201911334425A CN 112664953 A CN112664953 A CN 112664953A
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Abstract
The invention relates to the technical field of boiler structures, in particular to a circulating fluidized bed incineration boiler for burning solid wastes, which can effectively reduce the corrosion effect, does not have the phenomenon of material blockage, has continuous and stable combustion and standard smoke emission, and comprises a hearth, a separator device and a tail flue which are sequentially arranged, wherein a material returning device is arranged between the separator device and the hearth, a feeding pipe and a secondary air pipe are arranged on the side wall of the hearth, a fluidized bed is arranged at the bottom of the hearth, an ignition device and primary air are arranged at the position of the fluidized bed, the circulating fluidized bed incineration boiler is characterized in that the hearth is composed of a water-cooled wall, a fire-resistant material layer is laid on the fire-facing surface of the hearth, the aperture ratio of an air distribution plate of the fluidized bed is 2-4 percent, air cooling caps on the air distribution plate are arranged in a staggered manner, the air distribution plate is connected with a slag discharging pipe, the air cooling flue is arranged, the tail flue comprises a front ascending flue and a rear descending flue.
Description
Technical Field
The invention relates to the technical field of boiler structures, in particular to a circulating fluidized bed incineration boiler for burning solid wastes.
Background
With the development of industry, the increasing development of urban construction and the continuous improvement of the living standard of people, the emission of urban domestic garbage and industrial waste is increased day by day, which causes increasingly serious environmental problems. Environmental protection policies are becoming stricter, and the principle of treating solid wastes who generates is developed in various places, so that the solid wastes cannot be treated (buried) at will or cannot be discharged from regions and can be treated only locally. According to the regulation of the environmental protection and control law of solid waste pollution, the solid waste treatment needs to follow the principle of three changes, namely harmlessness, reduction and recycling, so that the incineration of the solid waste in a boiler is a more common treatment mode, toxic and harmful organic matters in the solid waste can be incinerated cleanly, the volume is reduced, and meanwhile, the solid waste has a certain heat value and can be used for power generation and heat supply.
Because industrial solid wastes such as paper residues, sludge, cloth strips and the like and solid wastes such as sludge and the like generated after urban sewage treatment have the following characteristics:
1. the fuel has a certain heat value, the heat value and components of the fuel have certain fluctuation, the operation is unstable by adopting other combustion modes, and the long-term continuous stable operation cannot be realized by adopting other combustion modes;
2. the water content is high, the corrosive components such as chlorine and the like are contained, and the flue gas generated after combustion is easy to corrode, including high-temperature corrosion and low-temperature corrosion;
3. although the fuel is subjected to pretreatment such as tapping, deslagging and the like before entering the furnace, the fuel entering the furnace still contains a small amount of components such as iron wires, glass slag and the like, if the fuel is not discharged out of the furnace in time, a large amount of iron wires are accumulated along with the extension of the operation time, the iron wires in a bed layer are easy to tangle and difficult to discharge, the ash melting point of the glass slag and the like is low, and the air cap is easy to plug, so that the continuous operation time is short;
3. the ash generated in the combustion process has the characteristics of easy adhesion, low ash melting point, special components and high content of alkaline substances. At present, a small amount of coal is mixed with coal for burning in China, and various problems of separator coking, poor material return, flue blockage by tail fly ash and the like generally exist.
And 4, CO emission exceeds the standard and cannot meet the requirements of the national environmental protection standard.
The existing boiler can not solve the technical problems.
Disclosure of Invention
The invention provides a circulating fluidized bed incineration boiler for combusting solid wastes, which can effectively reduce the corrosion effect, avoid the phenomenon of material blockage, realize continuous and stable combustion and achieve the standard of smoke emission, and aims to solve the problems that the combustion of the solid wastes by the existing boiler is unstable, coking and material blockage are easy to occur, and the smoke is corroded and does not reach the standard.
The technical scheme is as follows: a circulating fluidized bed incineration boiler for burning solid wastes comprises a hearth, a separator device and a tail flue which are sequentially arranged, wherein a material returning device is arranged between the separator device and the hearth, a feeding pipe and a secondary air pipe are arranged on the side wall of the hearth, a fluidized bed is arranged at the bottom of the hearth, an ignition device and primary air are arranged at the position of the fluidized bed, the circulating fluidized bed incineration boiler is characterized in that the hearth is composed of a water-cooled wall, a fire-resistant material layer is laid on the fire-facing surface of the hearth, the aperture ratio of an air distribution plate of the fluidized bed is 2% -4%, air hoods on the air distribution plate are arranged in a staggered manner, the air distribution plate is connected with a slag discharging pipe, an air cooling flue is arranged between the separator device and the tail flue, an ash discharging pipe is arranged at the bottom of the material returning device, a high-temperature superheater is installed in the material returning device, and the tail, an evaporator, a low-temperature superheater and a high-temperature economizer are sequentially arranged in the front ascending flue from bottom to top, and an SCR (selective catalytic reduction) region, a low-temperature economizer and an air preheater are sequentially arranged in the rear descending flue from top to bottom.
The furnace is further characterized in that at least two slag discharging pipes are arranged along the width direction of the hearth, and the diameter of each slag discharging pipe is larger than 250 mm;
a soot blower is arranged in the tail flue, and heating surfaces of the evaporator, the low-temperature superheater, the high-low temperature economizer and the air preheater are arranged in sequence;
the evaporator is connected with the steam drum through a downcomer;
the air preheater is a stainless steel pipe or an enamel pipe;
the temperature of the fluidized bed is 900-920 ℃;
the combustion temperature of the hearth is not lower than 850 ℃, and the retention time of the flue gas in the hearth is not lower than 2 s.
After the invention is adopted, a refractory material layer is laid on the fire facing surface of the hearth, a heating surface is not arranged in a high-temperature area, a high-temperature superheater is arranged in the material returning device, the problem of high-temperature corrosion is effectively solved, the aperture ratio is improved at the air distribution plate, the ash discharge pipe is arranged, the problem of material blockage is effectively solved, the ash discharge pipe is arranged at the lower part of the material returning device, the material returning quantity is adjusted, the effects of controlling the concentration of fly ash in the furnace and heat transfer are achieved, the temperature of the hearth is kept at a stable combustion temperature of more than 850 ℃ when solid waste fuel fluctuates, an air cooling flue is added, the combustion time of flue gas in a high-temperature area is prolonged, the regeneration of dioxin is inhibited, and the.
Drawings
FIG. 1 is a schematic view of the structure of the present invention.
Detailed Description
As shown in figure 1, the circulating fluidized bed incineration boiler for burning solid wastes comprises a hearth 2, a steam-cooled separator 3 and a tail flue which are sequentially arranged, a material returning device 4 is arranged between the steam-cooled separator 3 and the hearth 2, a feeding pipe 17 and a secondary air pipe 31 are arranged on the side wall of the hearth 2, a fluidized bed 30 is arranged at the bottom of the hearth 2, an ignition device 19 and primary air are arranged at the position of the fluidized bed 30, the hearth 2 is composed of a water-cooled wall, a refractory material layer is laid on the fire-facing surface of the hearth, the opening rate of an air distribution plate of the fluidized bed 30 is 2-4%, air hoods on the air distribution plate are arranged in a staggered mode, the air hood heads are round heads, the air distribution plate is connected with a slag discharge pipe 18, the slag discharge pipe 18 is connected with a slag cooler 15, at least two slag discharge pipes 18 are arranged along the width direction of the hearth, the diameter of the slag discharge pipe 18 is larger than 250mm so as to facilitate discharge of iron nails and the like, the regeneration of dioxin is inhibited by prolonging the flue gas combustion time in a high-temperature area (650 plus 850 ℃), and meanwhile, the combustion temperature of a hearth is controlled to be not lower than 850 ℃, the residence time of the flue gas of the hearth is controlled to be not lower than 2 seconds, so that the generation of dioxin is further reduced, fuel is fully combusted, the lower the CO concentration is, the more the combustion is, and the lower the emission of dioxin is.
The solid waste fuel has great heat value and component fluctuation, and this results in difficult combustion operation and control. Therefore, an ash discharge pipe is arranged at the lower part of the material returning device 4, a cold ash device is arranged to adjust the material returning amount, the functions of controlling the concentration of fly ash in the furnace and heat transfer are achieved, the temperature of a hearth is kept at a stable combustion temperature of more than 850 ℃ when solid waste fuel fluctuates, and the bottom of the ash discharge pipe is connected with a material returning cold ash device 16.
Install high temperature over heater 14 in the material returning device 4, be full of material returning high temperature ash in the material returning device 14, interior no high temperature corrosivity flue gas, the problem of high temperature over heater corruption has been solved, afterbody flue includes preceding uptake flue 4 and back decline flue 9, is provided with evaporimeter 6, low temperature over heater 7, high temperature economizer 8 from supreme down in the preceding uptake flue in order, is provided with SCR district 10, low temperature economizer 11, air heater 12 from last to down in the back decline flue in order.
After solid waste is incinerated, generated fly ash is separated by a separator, the fly ash is fine in particle size, the fly ash contains high content of alkaline substances such as potassium oxide and sodium oxide, the alkaline substances are easy to adhere between tube bundles, and a flue is blocked strictly, so that a conventional soot blower is arranged in a flue at the tail part, and heating surfaces of an evaporator 6, a low-temperature superheater 7, a high-temperature economizer 8, a low-temperature economizer 11 and an air preheater 12 are arranged in sequence, soot blowing is easy, different transverse pitches are selected in different regions, and the fly ash is prevented from being bridged transversely and blocking the flue.
The tube wall temperature is in the 0-dew point temperature and 420-700 ℃, and the corrosion is increased sharply. The 0-dew point temperature area is the area of the air preheater, HCl gas enters condensed water drops outside the tube wall to form hydrochloric acid, and strong corrosion is formed on the metal of the tube wall. In the interval of the dew point to about 420 ℃, the corrosion speed is very low, and the temperature area is a high-low temperature economizer area and a low-temperature superheater area. But from 450 c to 750 c, corrosion rises sharply. And the area is just a high-temperature superheater and is just in a strong corrosion area.
The evaporator 6 is connected with the steam pocket 1 through the downcomer 27, the steam pocket 1 introduces water into the evaporator 6, the natural circulation is adopted, although the flue gas temperature is high, the temperature of the medium in the pipe is saturated temperature, so the pipe wall temperature is low, and high-temperature corrosion cannot be generated; an evaporator 6 is arranged in front of the low-temperature superheater 7, and the temperature of a low-pass medium is controlled to be not more than 380 ℃, so that the temperature of the tube wall of the low-temperature superheater 7 is not more than 420 ℃, and high-temperature corrosion of the low-temperature superheater 7 is prevented; the air preheater 12 is a stainless steel tube or an enamel tube, which can reduce low temperature corrosion.
In order to organize the good combustion of the fuel in the boiler and control the generation of CO, the air preheater 12 comprises a primary air inlet, a secondary air inlet, a primary air outlet and a secondary air outlet, the primary air outlet is communicated with a primary air port of the ignition device 19 through a primary air pipeline 32, and the secondary air outlet is communicated with a secondary air pipe 31 through a secondary air pipeline 33.
The boiler water inlet is connected with the low-temperature economizer 11, the outlet of the low-temperature economizer 11 is connected with the inlet of the high-temperature economizer 8 through a first pipeline 25, the outlet of the high-temperature economizer 8 is connected with the water inlet of the steam pocket 1 through a second pipeline 26, the water outlet of the steam pocket 1 is connected with the water inlets of the membrane type walls of the hearth 2, the evaporator 6 and the wall wrapping pipe 22 through a descending pipe 27, and the water outlets at the upper parts of the membrane type walls of the hearth, the evaporator and the wall wrapping pipe are connected with the steam pocket 1 through a water inlet pipe 29.
The working principle of the invention is as follows: boiler feed water enters a low-temperature economizer 11 and a high-temperature economizer 8, the boiler feed water enters a steam drum 1 after being heated by smoke, boiler water in the steam drum 1 respectively enters a membrane type wall of a hearth 2 through a downcomer 27, the boiler water in the membrane type wall of the hearth 2 is heated by the smoke to form a steam-water mixture, the steam-water mixture enters a boiler barrel 1, the steam-water mixture is divided into saturated steam and saturated boiler water in the boiler barrel 1 through a steam-water separation device, and the boiler water enters the downcomer; saturated steam is introduced into the steam-cooling separator 3 through a first connecting pipe 21, the saturated steam heated at the outlet of the steam-cooling separator 3 becomes superheated steam, the superheated steam is introduced into the low-temperature superheater 7 through a second connecting pipe 22, then the superheated steam sequentially enters the primary water-spraying desuperheater 23 and the high-temperature superheater 8, the superheated steam reaching the rated parameters of the boiler is introduced into a steam outlet header 23 through the connecting pipes and is output to the boiler for supplying heat or entering a steam turbine to do work and generate power.
The solid waste is conveyed by wind power to be sent into a combustion chamber at the lower part of a hearth 2 from a feed pipe 17 in front of the furnace, high-temperature flue gas generated after fuel combustion sequentially transfers heat to a membrane wall of the hearth 2, a steam-cooled separator 3, an air cooling flue 5, a low-temperature superheater 7, a high-temperature economizer 8, a low-temperature economizer 11 and an air preheater 12, the flue gas after temperature reduction is discharged out of the boiler through an outlet flue 13, the flue gas which meets national emission indexes after dust removal, desulfurization and the like is discharged from a chimney, and slag after fuel combustion is discharged out of the boiler through a slag discharge pipe 15.
High-temperature flue gas generated after fuel combustion is separated in a steam-cooling separator 3, fine particles enter a tail convection heating surface along with the flue gas, larger particles are separated and are sent into a hearth 2 through a material returning device 4 to form circulation, in the process, the hot particles transfer heat to the steam-cooling separator 4, the hearth membrane wall heating surface and a high-temperature superheater 14 arranged in a material returning device, and a bed ignition device 19 uses light diesel oil and is used when a boiler is ignited.
Claims (7)
1. A circulating fluidized bed incineration boiler for burning solid wastes comprises a hearth, a separator device and a tail flue which are sequentially arranged, wherein a material returning device is arranged between the separator device and the hearth, a feeding pipe and a secondary air pipe are arranged on the side wall of the hearth, a fluidized bed is arranged at the bottom of the hearth, an ignition device and primary air are arranged at the position of the fluidized bed, the circulating fluidized bed incineration boiler is characterized in that the hearth is composed of a water-cooled wall, a fire-resistant material layer is laid on the fire-facing surface of the hearth, the aperture ratio of an air distribution plate of the fluidized bed is 2% -4%, air hoods on the air distribution plate are arranged in a staggered manner, the air distribution plate is connected with a slag discharging pipe, an air cooling flue is arranged between the separator device and the tail flue, an ash discharging pipe is arranged at the bottom of the material returning device, a high-temperature superheater is installed in the material returning device, and the tail, an evaporator, a low-temperature superheater and a high-temperature economizer are sequentially arranged in the front ascending flue from bottom to top, and an SCR (selective catalytic reduction) region, a low-temperature economizer and an air preheater are sequentially arranged in the rear descending flue from top to bottom.
2. The circulating fluidized bed incineration boiler combusting solid waste according to claim 1, wherein at least two slag discharging pipes are arranged along the width direction of the hearth, and the diameter of the slag discharging pipe is larger than 250 mm.
3. The circulating fluidized bed incineration boiler for burning solid wastes according to claim 1, wherein a soot blower is arranged in the tail flue, and heating surfaces of the evaporator, the low-temperature superheater, the high-low temperature economizer and the air preheater are arranged in series.
4. The circulating fluidized bed incineration boiler combusting solid waste according to claim 1, wherein the evaporator is connected to the drum through a downcomer.
5. The circulating fluidized bed incineration boiler combusting solid waste according to claim 1, wherein the air preheater is a stainless steel tube or an enamel tube.
6. The circulating fluidized bed incineration boiler combusting solid waste as claimed in claim 1, wherein the temperature of the fluidized bed is 900-920 ℃.
7. The circulating fluidized bed incineration boiler for burning solid waste according to claim 1, wherein the combustion temperature of the furnace is not lower than 850 ℃, and the residence time of the flue gas in the furnace is not lower than 2 s.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201911334425.5A CN112664953A (en) | 2019-12-23 | 2019-12-23 | Circulating fluidized bed incineration boiler for burning solid waste |
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| CN201911334425.5A CN112664953A (en) | 2019-12-23 | 2019-12-23 | Circulating fluidized bed incineration boiler for burning solid waste |
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| CN112664953A true CN112664953A (en) | 2021-04-16 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113566209A (en) * | 2021-06-23 | 2021-10-29 | 联盛纸业（龙海）有限公司 | Method and system for inhibiting low-temperature corrosion of boiler air preheater |
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2019
- 2019-12-23 CN CN201911334425.5A patent/CN112664953A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113566209A (en) * | 2021-06-23 | 2021-10-29 | 联盛纸业（龙海）有限公司 | Method and system for inhibiting low-temperature corrosion of boiler air preheater |
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