CN211260748U - High-temperature and high-pressure steam boiler of pure-burning biomass environment-friendly circulating fluidized bed - Google Patents

Abstract

An environment-friendly circulating fluidized bed high-temperature and high-pressure steam boiler for pure-burning biomass relates to a circulating fluidized bed boiler. The utility model provides a current living beings circulating fluidized bed boiler have combustion efficiency low, pollutant discharge many, the fuel scope is narrow, the pure difficulty of burning, the feed is smooth, sealed not tight and the poor problem of reliability. The feeding interface is positioned at a negative pressure point at the lower part of the hearth; a water-cooling screen, a medium-temperature screen superheater and a high-temperature screen superheater are sequentially arranged on the upper part of the hearth in the width direction; the first inlet flue and the second inlet flue are communicated with each other at one end, the first inlet flue and the second inlet flue are arranged in a downward inclination mode, the downward inclination angle of the first inlet flue is smaller than the downward inclination angle of the second inlet flue, the other end of the second inlet flue is communicated with the upper end side wall of the separator, the lower end of the steering chamber is communicated with the upper end of the separator, the central cylinder is connected with the lower end of the steering chamber, and the central cylinder is located in the separator. The utility model is used for pure burning living beings circulating fluidized bed boiler combined heat and power generation.

Description

High-temperature and high-pressure steam boiler of pure-burning biomass environment-friendly circulating fluidized bed

Technical Field

The utility model relates to a living beings circulating fluidized bed boiler, concretely relates to pure fever living beings environment-friendly circulating fluidized bed high temperature high pressure steam boiler.

Background

According to the requirement of the national instruction for promoting the development of biomass energy heat supply and the development of local area coal limitation and coal prohibition work in China, the development of the biomass circulating fluidized bed boiler is accelerated, and clean combustion, low pollution emission, stable load and safe operation are required to be achieved. The outdoor incineration and the composting storage of the agriculture and forestry biomass can cause the damage of haze, fire and the like to the environment; the pollution to natural resources can be caused by improper harmless disposal of the livestock husbandry wastes.

With the increasing strictness and perfection of environmental protection and energy conservation, the circulating fluidized bed combustion technology is rapidly developed due to the environmental protection performance, and the development and application of an environment-friendly and energy-saving biomass circulating fluidized bed boiler are promoted.

According to various problems of the pure-burning biomass circulating fluidized bed boiler, particularly the problems of difficult pure-burning of biomass, short continuous operation time, low boiler efficiency and the like, research is carried out, the pure-burning biomass environment-friendly circulating fluidized bed boiler with pure burning, low emission, high reliability and low accident rate is developed, and the problems of difficult pure burning, low parameters and low unit efficiency of the conventional boiler are solved.

In conclusion, the existing biomass circulating fluidized bed boiler has the advantages of low combustion efficiency, more pollution emission, narrow fuel range, difficulty in pure combustion, unsmooth feeding, poor sealing and poor reliability.

SUMMERY OF THE UTILITY MODEL

The utility model discloses a solve present living beings circulating fluidized bed boiler and have that combustion efficiency is low, pollutant discharge is many, the fuel scope is narrow, the problem that the difficulty was burnt in pure, the feed is not smooth, sealed not tight and the reliability is poor, and then provide a pure living beings environment-friendly circulating fluidized bed high temperature high pressure steam boiler that burns.

The utility model discloses a solve the technical scheme that above-mentioned technical problem took and be:

the utility model discloses a pure burning living beings environment-friendly circulating fluidized bed high temperature high pressure steam boiler includes pure burning living beings feed system 1, ignition, 2, arrange ash sediment device 3, furnace 4, separation returning charge system 5, packet wall superheater 6, air heater 7, environmental protection interface 8, feed water header 9, economizer 10, feed water distribution pipe 11, boiler barrel 12, concentrate downcomer 13, water screen downcomer 14, water screen 15, water screen eduction tube 16, water-cooling steam guide 20, steam eduction tube 21, side packet wall 22, preceding packet wall 23, back packet wall 24, low temperature superheater 25, one-level water spray desuperheater 26, medium temperature superheater 27, second grade water spray desuperheater 28, medium temperature screen superheater 29, tertiary water spray desuperheater 30, high temperature screen 31 and steam header 32;

the pure-burning biomass feeding system 1 comprises lower-level secondary air 1-2, upper-level secondary air 1-3 and a plurality of feeding interfaces 1-1, wherein the upper-level secondary air 1-3 and the lower-level secondary air 1-2 are sequentially arranged at the lower part of a hearth 4 from top to bottom, the feeding interfaces 1-1 are arranged in front of a furnace, are positioned between the upper-level secondary air 1-3 and the lower-level secondary air 1-2 and are positioned at a negative pressure point at the lower part of the hearth, and the plurality of feeding interfaces 1-1 are sequentially arranged along the width direction of the hearth 4;

the ignition device 2 is positioned at the rear side of the bottom of the hearth 4, and the ignition device 2 is a natural gas ignition device;

the ash discharging device 3 comprises an ash discharging pipe 3-1 and a slag discharging pipe 3-2, wherein the ash discharging pipe 3-1 and the slag discharging pipe 3-2 are both arranged at the bottom end of the hearth 4 and are communicated with the hearth 4;

a front water-cooled wall, a side water-cooled wall and a rear water-cooled wall are arranged in the hearth 4; the upper part of the hearth 4 is sequentially provided with a water-cooling screen 15, a medium-temperature screen superheater 29 and a high-temperature screen superheater 31 from top to bottom;

the separating and returning system 5 comprises a separator 5-1, a first inlet flue 5-2, a second inlet flue 5-3, a central cylinder 5-4, a turning chamber 5-5, a returning device 5-6 and a returning leg 5-7, wherein one end of the first inlet flue 5-2 is communicated with one end of the second inlet flue 5-3, the first inlet flue 5-2 and the second inlet flue 5-3 are both arranged in a declining way, the declining angle of the first inlet flue 5-2 is smaller than that of the second inlet flue 5-3, the other end of the second inlet flue 5-3 is communicated with the upper end side wall of the separator 5-1, the lower end of the turning chamber 5-5 is communicated with the upper end of the separator 5-1, the central cylinder 5-4 is connected with the lower end of the turning chamber 5-5, and the central cylinder 5-4 is positioned in the separator 5-1, the material returning device 5-6 and the material returning leg 5-7 are positioned at the bottom of the separator 5-1;

the wall-wrapped superheater 6 comprises a side wall-wrapped 22 superheater, a front wall-wrapped 23 superheater and a rear wall-wrapped 24 superheater, and a medium-temperature superheater 27 and a low-temperature superheater 25 are arranged on the upper part of the wall-wrapped superheater 6 from top to bottom;

the economizer 10 and the air preheater 7 form a tail heating surface, the tail heating surface is positioned below the wall-wrapped superheater 6, the economizer 10 and the air preheater 7 are sequentially arranged from top to bottom, the air preheater 7 comprises a superior air preheater 7-1, a middle air preheater 7-2, a subordinate air preheater 7-3 and an outlet flue 7-4, and the superior air preheater 7-1, the middle air preheater 7-2, the subordinate air preheater 7-3 and the outlet flue 7-4 are sequentially arranged from top to bottom;

the environment-friendly interface 8 comprises a denitration interface 8-1 and a desulfurization interface 8-2, the denitration interface 8-1 is arranged on a first inlet flue 5-2 of the separator 5-1, and the desulfurization interface 8-2 is arranged on a material returning leg 5-7 of the material returning device 5-6;

the upper side face of the separation material returning system 5 is communicated with the upper part of the hearth 4, the material returning legs 5-7 at the bottom of the separation material returning system 5 are communicated with the bottom of the hearth 4, and the turning chamber 5-5 at the top of the separation material returning system 5 is communicated with the inlet of the wall-wrapping superheater 6.

In one embodiment, the cross section of the feeding interface 1-1 is rectangular, the cross section size of the feeding interface 1-1 is 800x800mm, the feeding interface 1-1 is arranged in a downward inclination mode, the downward inclination angle a of the feeding interface is 10-15 degrees, and a zero pressure point is arranged between the feeding interface 1-1 and the lower secondary air 1-2.

In one embodiment, the number of the ash discharge pipes 3-1 is three, the diameter of the ash discharge pipe 3-1 is phi 273mm, the number of the slag discharge pipes 3-2 is two, and the diameter of the slag discharge pipe 3-2 is phi 325 mm.

In one embodiment, the ash discharge pipes 3-1 are sequentially arranged along the width direction of the hearth 4, and one slag discharge pipe 3-2 is arranged between every two adjacent ash discharge pipes 3-1.

In one embodiment, the first inlet stack 5-2 has a downward inclination b of 5 ° and the second inlet stack 5-3 has a downward inclination c of 10 °.

In one embodiment, the wall-enclosed superheater 6 is enclosed by a side wall-enclosed 22 superheater, a front wall-enclosed 23 superheater, and a rear wall-enclosed 24 superheater.

In one embodiment, the plurality of feeding ports 1-1 are uniformly distributed in sequence along the width direction of the hearth 4.

In one embodiment, the air preheaters 7 are of a horizontal tube structure, the number of the upper-stage air preheaters 7-1 and the number of the middle-stage air preheaters 7-2 are two groups, and the number of the lower-stage air preheaters 7-3 are one group.

The utility model has the advantages that:

the biomass fuel of the utility model can adopt agriculture and forestry biomass dispersed fuel, and can also adopt agriculture and forestry biomass briquette fuel, the briquette fuel can be compressed into the shapes of block or column, and the fuel range is wide;

the high-temperature high-pressure steam boiler of the environment-friendly circulating fluidized bed for pure-burning biomass directly feeds through the butt joint and downdip type pure-burning biomass feeding interface of the screw feeder, thereby realizing smooth feeding and effective sealing and preventing smoke from reversely flowing;

the feeding interface of the environment-friendly circulating fluidized bed high-temperature high-pressure steam boiler for pure-burning biomass is arranged at the negative pressure point at the lower part of the hearth, and biomass enters the boiler along with upper secondary air and lower secondary air, so that feeding unsmooth and flue gas backflow are effectively prevented;

the high-temperature and high-pressure steam boiler of the environment-friendly circulating fluidized bed for pure-burning biomass has the advantages that because the ash content in the biomass fuel is less, the material is added through the biomass feeding interface to be used as circulating ash, the condensate on the surface of the heating surface of the hearth can be washed away, and the ash accumulation and corrosion are avoided;

the biomass fuel of the environment-friendly circulating fluidized bed high-temperature high-pressure steam boiler burning pure biomass has high volatile component and low ignition point, is suitable for air supply proportion and graded air supply, is more suitable for the characteristic of large combustion share at the upper part of a hearth of the biomass fluidized bed boiler, and simultaneously can be adjusted by reasonably distributing the proportion of primary air to secondary air to be 5:5, so as to be suitable for the characteristic of large water fluctuation of biomass;

the utility model fully considers the factors of biomass fuel diversity, boiler load change and the like, arranges enough heating surfaces in the hearth for heat exchange, and prolongs the stay and burning time of the fuel in the hearth by improving the height of the hearth; meanwhile, a large number of heating surfaces such as a water-cooling screen, a medium-temperature screen superheater, a high-temperature screen superheater and the like are arranged on the upper part of the hearth, so that the temperature of the outlet of the hearth is reduced, the temperature of the outlet of the hearth is maintained at about 800 ℃, coking can be effectively prevented, sufficient combustion is guaranteed, and the reliability of the boiler is improved;

the environment-friendly circulating fluidized bed high-temperature high-pressure steam boiler with pure-burning biomass selects a larger excess air coefficient of about 1.4 in the hearth, realizes the intensified combustion of the lower part of the hearth, and ensures the combustion temperature, thereby improving the combustion efficiency by more than 30 percent;

the utility model discloses a pure burning living beings environment-friendly circulating fluidized bed high temperature high pressure steam boiler has constructed the reduction field region of graded air supply, oxygen deficiency burning of no gradient, has realized the redox atmosphere reforming based on bed quality improvement to the degree of depth has inhibited NOx's original formation, and the pollutant discharge who alleviates greatly alleviates, and the pollutant discharge alleviates more than 20%.

Drawings

FIG. 1 is a main sectional view of the high-temperature high-pressure steam boiler of the pure biomass-fired environment-friendly circulating fluidized bed of the present invention;

fig. 2 is a sectional view of the high-temperature and high-pressure steam boiler of the environment-friendly circulating fluidized bed for pure biomass combustion of the present invention (the left half is a left sectional view from a to a in fig. 1, and the right half is a right half sectional view from B to B in fig. 1);

FIG. 3 is a top view of the high-temperature and high-pressure steam boiler of the environmentally friendly circulating fluidized bed with pure biomass combustion according to the present invention (the upper half is the sectional view C-C of FIG. 1, and the lower half is the sectional view D-D of FIG. 1);

FIG. 4 is a top view of the high-temperature high-pressure steam boiler of the environmentally friendly circulating fluidized bed with pure biomass combustion according to the present invention (the upper half is a cross-sectional view E-E of FIG. 1, and the lower half is a cross-sectional view F-F of FIG. 1);

FIG. 5 is a schematic structural diagram of a hearth 4 according to a first embodiment of the present invention;

FIG. 6 is a top cross-sectional view of a furnace 4 according to a first embodiment of the present invention (the upper half is the cross-sectional view G-G of FIG. 5, and the lower half is the cross-sectional view J-J of FIG. 5);

FIG. 7 is a top sectional view of the furnace 4 according to the first embodiment of the present invention;

FIG. 8 is a front cross-sectional view of a separated return system 5 according to a first embodiment of the present invention;

FIG. 9 is an enlarged view of section I of FIG. 8;

FIG. 10 is an enlarged view of section II of FIG. 8;

FIG. 11 is a front sectional view of a tundish wall superheater 6 according to a first embodiment of the present invention;

fig. 12 is a front view of an air preheater 7 according to an embodiment of the present invention.

In the figure: the system comprises a pure-burning biomass feeding system 1, an ignition device 2, an ash discharging device 3, a hearth 4, a separation return system 5, a wall-covered superheater 6, an air preheater 7, an environment-friendly interface 8, a water supply header 9, a coal economizer 10, a water supply distribution pipe 11, a boiler barrel 12, a centralized downcomer 13, a water screen downcomer 14, a water screen 15, a water screen eduction pipe 16, a water-cooling steam guide pipe 20, a steam eduction pipe 21, a side wall 22, a front wall 23, a rear wall 24, a low-temperature superheater 25, a primary water spray desuperheater 26, a medium-temperature superheater 27, a secondary water spray desuperheater 28, a medium-temperature screen 29, a tertiary water spray desuperheater 30, a high-temperature screen 31 and a steam collection header 32.

Detailed Description

The first embodiment is as follows: as shown in fig. 1 to 11, the pure-burned biomass environment-friendly circulating fluidized bed high-temperature and high-pressure steam boiler of the present embodiment includes a pure-burned biomass feeding system 1, an ignition device 2, an ash and slag discharging device 3, a furnace 4, a separation and return system 5, a wall-wrapped superheater 6, an air preheater 7, an environment-friendly interface 8, a water supply header tank 9, an economizer 10, a water supply distribution pipe 11, a boiler barrel 12, a central down pipe 13, a water-cooled screen down pipe 14, a water-cooled screen 15, a water-cooled screen outlet pipe 16, a water-cooled steam guide pipe 20, a steam outlet pipe 21, a side-wrapped wall 22, a front wrapped wall 23, a rear wrapped wall 24, a low-temperature superheater 25, a primary water-spraying desuperheater 26, a medium-temperature superheater 27, a secondary water-spraying desuperheater 28, a medium-temperature screen superheater 29, a tertiary water;

the pure-burning biomass feeding system 1 comprises lower-level secondary air 1-2, upper-level secondary air 1-3 and a plurality of feeding interfaces 1-1, wherein the upper-level secondary air 1-3 and the lower-level secondary air 1-2 are sequentially arranged at the lower part of a hearth 4 from top to bottom, the feeding interfaces 1-1 are arranged in front of a furnace, are positioned between the upper-level secondary air 1-3 and the lower-level secondary air 1-2 and are positioned at a negative pressure point at the lower part of the hearth, and the plurality of feeding interfaces 1-1 are sequentially arranged along the width direction of the hearth 4;

the ignition device 2 is positioned at the rear side of the bottom of the hearth 4, and the ignition device 2 is a natural gas ignition device;

the ash discharging device 3 comprises an ash discharging pipe 3-1 and a slag discharging pipe 3-2, wherein the ash discharging pipe 3-1 and the slag discharging pipe 3-2 are both arranged at the bottom end of the hearth 4 and are communicated with the hearth 4;

a front water-cooled wall, a side water-cooled wall and a rear water-cooled wall are arranged in the hearth 4; the upper part of the hearth 4 is sequentially provided with a water-cooling screen 15, a medium-temperature screen superheater 29 and a high-temperature screen superheater 31 from top to bottom;

the separating and returning system 5 comprises a separator 5-1, a first inlet flue 5-2, a second inlet flue 5-3, a central cylinder 5-4, a turning chamber 5-5, a returning device 5-6 and a returning leg 5-7, wherein one end of the first inlet flue 5-2 is communicated with one end of the second inlet flue 5-3, the first inlet flue 5-2 and the second inlet flue 5-3 are both arranged in a declining way, the declining angle of the first inlet flue 5-2 is smaller than that of the second inlet flue 5-3, the other end of the second inlet flue 5-3 is communicated with the upper end side wall of the separator 5-1, the lower end of the turning chamber 5-5 is communicated with the upper end of the separator 5-1, the central cylinder 5-4 is connected with the lower end of the turning chamber 5-5, and the central cylinder 5-4 is positioned in the separator 5-1, the material returning device 5-6 and the material returning leg 5-7 are positioned at the bottom of the separator 5-1;

the wall-wrapped superheater 6 comprises a side wall-wrapped superheater 22, a front wall-wrapped superheater 23 and a rear wall-wrapped superheater 24, and a medium-temperature superheater 27 and a low-temperature superheater 25 are arranged on the upper part of the wall-wrapped superheater 6 from top to bottom;

the economizer 10 and the air preheater 7 form a tail heating surface, the tail heating surface is positioned below the wall-wrapped superheater 6, the economizer 10 and the air preheater 7 are sequentially arranged from top to bottom, the air preheater 7 comprises a superior air preheater 7-1, a middle air preheater 7-2, a subordinate air preheater 7-3 and an outlet flue 7-4, and the superior air preheater 7-1, the middle air preheater 7-2, the subordinate air preheater 7-3 and the outlet flue 7-4 are sequentially arranged from top to bottom;

the environment-friendly interface 8 comprises a denitration interface 8-1 and a desulfurization interface 8-2, the denitration interface 8-1 is arranged on a first inlet flue 5-2 of the separator 5-1, and the desulfurization interface 8-2 is arranged on a material returning leg 5-7 of the material returning device 5-6;

the upper side face of the separation material returning system 5 is communicated with the upper part of the hearth 4, the material returning legs 5-7 at the bottom of the separation material returning system 5 are communicated with the bottom of the hearth 4, and the turning chamber 5-5 at the top of the separation material returning system 5 is communicated with the inlet of the wall-wrapping superheater 6.

If the biomass fuel of the utility model adopts agriculture and forestry biomass dispersed fuel, the length of the biomass fuel is controlled within 100 mm; if the agriculture and forestry biomass briquette fuel is adopted, the briquette fuel can be compressed into a block shape or a columnar shape and the like, and the length is controlled within 50 mm;

the secondary air is divided into two stages of lower secondary air 1-2 and upper secondary air 1-3, and a larger secondary air proportion is set, so that the secondary air is suitable for the characteristic of large combustion share at the upper part of the hearth; the combustion can be intensified by selecting a larger excess air coefficient, so that the combustion efficiency is prevented from being reduced due to low combustion temperature;

the cross restriction is adopted when the air quantity and the biomass fuel are regulated and combusted, and when the load of the boiler is increased, air is added firstly and then the fuel is added; when the load is reduced, the fuel is reduced firstly and then the air is reduced, so that the fuel-rich working condition in the hearth can be avoided when the load of the boiler is changed, the reducing atmosphere in the hearth can be avoided, and the bed material layer can be effectively prevented from coking;

compared with the traditional oil ignition, the ignition by adopting clean natural gas has superior environmental protection performance, and avoids oil contamination and black oil smoke pollution to a heating surface caused by incomplete ignition and combustion of traditional diesel oil;

the natural gas ignition is adopted, and the bag-type dust remover does not need to be disconnected when the boiler is started, so that the pollution and blockage of the oil ignition to the bag are avoided, and the dust emission in the initial ignition stage is ensured to meet the requirement;

the ash and slag discharging device 3 adjusts the bed pressure by properly increasing or decreasing the discharge capacity through respective switches, and can achieve the effects of adjusting the bed temperature and regulating the material return amount.

The utility model fully considers the factors of biomass fuel diversity, boiler load change and the like, arranges enough heating surfaces in the hearth for heat exchange, and prolongs the stay and burning time of the fuel in the hearth by improving the height of the hearth; a large number of heating surfaces such as a water-cooling screen 15, a medium-temperature screen superheater 29, a high-temperature screen superheater 31 and the like are arranged at the upper part of the hearth, so that the temperature of the outlet of the hearth is reduced and maintained at about 800 ℃, coking can be effectively prevented, and sufficient combustion is ensured;

the high-temperature screen superheater is made of TP347H material with corrosion resistance and high-temperature plasticity, is arranged in the hearth, and due to the adherence and backflow effects of circulating materials, no ash is deposited and slag is formed on the surface of the superheater, so that high-temperature corrosion under ash is effectively prevented, and the high-temperature screen superheater is ensured not to deform;

the steering chamber 5-5 adopts a split independent design, so that the ash collapse phenomenon caused by ash accumulation at the horizontal section of the steering chamber is reduced, and the smooth material return of a material return device and poor heat transfer caused by ash accumulation bridging of a superheater tube are avoided;

because the separation efficiency of the separator 5-1 is improved, the heat efficiency is improved, the fly ash amount is reduced, unburned ash particles in the biomass fuel cannot be brought to the tail flue, and the ash accumulation on the heating surface in the tail flue is greatly reduced;

because the efficiency of the separator is improved, the particle size of ash in the flue gas discharged from the separator is reduced, and the abrasion to the heating surface in the tail flue is greatly reduced;

the separator with high separation efficiency determines that the ash concentration in the separator is higher and the carbon content is lower; the separator is in an anoxic state, the material returning device is in a quick material returning state, and a separation material returning system cannot be coked and blocked;

by adopting the wall-wrapped superheater 6 structure, the heating surface is effectively increased, the sealing and heat insulation effects are better, the heat dissipation and air leakage are reduced, and the boiler efficiency is improved;

the low-temperature superheater 25 and the medium-temperature superheater 27 are arranged in the wall-wrapped superheater 6, so that the arrangement space can be saved, and the hoisting and connection of the wall-wrapped superheater are facilitated;

the coal economizer tubes are arranged in a row, so that soot blowing and ash removal are facilitated, and meanwhile, the pitch between the tubes is controlled, and the self-ash removal capability is enhanced under the condition of ensuring no abrasion;

the air preheater adopts a horizontal tube structure to prevent dust accumulation and blockage in the tube, the upper-level air preheater is made of a carbon steel tube, and the middle-level and lower-level air preheaters are made of enamel tubes to avoid low-temperature corrosion;

the reserved denitration mode adopts an SNCR mode, the reducing agent is ammonia water or urea, no catalyst is needed, and the denitration cost is reduced;

the reserved desulfurization mode adopts the dry desulfurization method of spraying limestone in the furnace, thereby avoiding secondary pollution of the wet desulfurization outside the furnace to the environment.

The second embodiment is as follows: as shown in fig. 1, 5 and 7, the cross section of the feeding port 1-1 of the present embodiment is rectangular, the cross section of the feeding port 1-1 has a size of 800x800mm, the feeding port 1-1 is arranged in a downward inclination manner, the downward inclination angle a of the feeding port is 10 to 15 °, and the zero pressure point is arranged between the feeding port 1-1 and the lower secondary air 1-2.

By the design, the feeding is convenient and the accumulation is avoided; the zero pressure point is between the biomass feed port 1-1 and the secondary air 1-2 at the lower stage, so that biomass negative pressure feeding is realized, the negative pressure is favorable for lighter biomass feeding, and the positive pressure feeding easily causes external spraying to pollute the environment because the density of the biomass is lower. Other components and connections are the same as those in the first embodiment.

The third concrete implementation mode: as shown in fig. 1, 5 and 7, the number of the ash discharge pipes 3-1 is three, the diameter of the ash discharge pipe 3-1 is phi 273mm, the number of the slag discharge pipes 3-2 is two, and the diameter of the slag discharge pipe 3-2 is phi 325 mm.

According to the design, the ash discharge pipe 5-1 adopts a pipe with the diameter of phi 273mm to discharge fine ash generated after biomass combustion, and a small-amount multi-row mode is adopted to avoid local ash coking to form slag blocks; the slag discharge pipe 5-2 adopts a pipe with the diameter of 325mm, and the large pipe diameter can smoothly discharge small slag blocks and unburned impurities and sundries entering a hearth along with biomass, so that slag blockage can be prevented, and accident shutdown caused by unsmooth slag discharge can be effectively avoided. Other components and connection relationships are the same as those in the first or second embodiment.

The fourth concrete implementation mode: as shown in fig. 1 and 7, the ash discharge pipes 3-1 of the present embodiment are sequentially arranged along the width direction of the furnace 4, and one slag discharge pipe 3-2 is arranged between two adjacent ash discharge pipes 3-1.

By the design, the ash discharging device 3 can properly increase or decrease the discharge capacity through respective switches to adjust the bed pressure, and the effect of adjusting the bed temperature and regulating the return amount can be achieved. Other components and connection relationships are the same as those in the third embodiment.

The fifth concrete implementation mode: as shown in fig. 8 and 9, in the present embodiment, the downward inclination angle b of the first inlet stack 5-2 is 5 °, and the downward inclination angle c of the second inlet stack 5-3 is 10 °.

By adopting the design, the efficiency of the separator is improved by adopting the design of the double-downdip long acceleration section of the flue, particles above 100 mu m can be completely separated, multiple cycles in the furnace are carried out, higher ash concentration in a hearth is ensured, and the sufficient combustion of biomass fuel is ensured; the inlet flue of the separator adopts a double-downdip design, so that the bottom of the flue is prevented from generating a horizontal section, the ash collapse phenomenon after ash accumulation at the bottom of the inlet flue is effectively prevented, and the fluctuation of boiler combustion after the ash collapse is avoided. The other components and the connection relations are the same as those of the first, second or fourth embodiment.

The sixth specific implementation mode: as shown in fig. 1 and 11, the wall-enclosed superheater 6 of the present embodiment is formed by enclosing a side wall 22 superheater, a front wall 23 superheater, and a rear wall 24 superheater.

So design adopts 6 structures on the wall of package over heater, effectively increases the heating surface, and has better sealed and adiabatic effect, reduces the heat dissipation and leaks out, improves boiler efficiency. The other components and the connection relationship are the same as those in the fifth embodiment.

The seventh embodiment: as shown in fig. 1 and 7, a plurality of feeding ports 1-1 of the present embodiment are sequentially and uniformly arranged along the width direction of the furnace 4.

By the design, the feeding is uniform, cross limitation of air quantity and biomass fuel during regulation and combustion is convenient to realize, and when the load of the boiler is increased, air is added firstly and then the fuel is uniform; when the load is reduced, the fuel is uniformly reduced firstly, and then the air is reduced, so that the fuel-rich working condition in the hearth can be avoided when the load of the boiler changes, the reducing atmosphere in the hearth can be avoided, and the coking of a bed material layer can be effectively prevented. Other components and connections are the same as in the first, second, fourth or sixth embodiments.

The specific implementation mode is eight: as shown in fig. 1, 2 and 12, the air preheater 7 of the present embodiment has a horizontal tube structure, and the number of the upper stage air preheaters 7-1 and the number of the middle stage air preheaters 7-2 are two, and the number of the lower stage air preheaters 7-3 is one. So design, air heater adopts horizontal tubular construction, prevents intraductal deposition and jam, and higher level air heater material is the carbon steel pipe, and middle-level, subordinate's air heater material are the enamel pipe, avoid low temperature corrosion, and the change after a set of subordinate's air heater is convenient for corrode. Other components and connection relationships are the same as those in the seventh embodiment.

The working process is as follows:

the biomass dispersed fuel and the formed fuel enter a hearth 4 through a feeding interface 1-1 in a pure-burning biomass feeding system 1, enter the lower part of the hearth 4 under the negative pressure action of secondary air 1-2 at the lower stage and secondary air 1-3 at the upper stage, are ignited and burnt through a natural gas ignition device 4, fine ash and small slag blocks of the biomass after burning are discharged through an ash and slag discharging device 3 at the bottom of the hearth 4, the fine ash is discharged through an ash discharging pipe 3-1, and the slag blocks which cannot pass through the ash discharging pipe 3-1 are discharged through a slag discharging pipe 3-2; smoke dust enters a separation material returning system 5 through an upper outlet of a hearth 4, the smoke dust is efficiently separated through a separator 5-1, large-particle dust enters a material returning device 5-6 and returns to the lower part of the hearth 4 to be continuously combusted, smoke gas and small-particle dust enter a turning chamber 5-5 through an upper outlet central cylinder 5-4 of the separator 5-1, enter a wall-wrapping heated surface through the turning chamber 5-5, enter a tail heated surface after heat exchange is carried out through a wall-wrapping superheater 6, a medium-temperature superheater 27 and a low-temperature superheater 25, and are discharged through an outlet flue 7-4 after heat exchange through an economizer 10 and an air preheater 7;

the primary hot air enters the bottom of the hearth 4 through the ignition device 2, and the biomass fed through the feeding interface 1-1 is ignited; secondary hot air enters the lower part of the hearth 4 through lower secondary air 1-2 and upper secondary air 1-3 to realize staged combustion, and supports combustion for biomass combustion to burn off the biomass;

biomass continuously burns in the middle of a hearth 4 and exchanges heat with steam heating surfaces such as a hearth heating surface, a water-cooling screen 15, a medium-temperature screen superheater 29, a high-temperature screen superheater 31 and the like in the hearth 4, smoke generated by burning is discharged from a rear side outlet at the upper part of the hearth 4 and enters a separating and returning system 5, the smoke is separated in a separator 5-1, and large-particle dust is separated and then returns to the lower part of the hearth 4 through a material returning device 5-6 and a material returning leg 5-7 to continue burning in the hearth 4; smoke dust carrying small-particle dust enters a wall-wrapping heating surface after entering a turning chamber 5-5 through a central cylinder 5-4, exchanges heat with a heating surface in a wall-wrapping superheater 6, sequentially flows through a side wall-wrapping 22 superheater, a front wall-wrapping 23 superheater, a rear wall-wrapping 24 superheater, a middle-temperature superheater 27 and a low-temperature superheater 25, enters a tail heating surface, exchanges heat with an economizer 10, enters an air preheater 7 after exchanging heat, exchanges heat through a higher-level air preheater 7-1, a middle-level air preheater 7-2 and a lower-level air preheater 7-3, and is finally discharged through an outlet flue 7-4;

the primary cold air and the secondary cold air exchange heat through the air preheater 7, and the heated primary hot air enters the bottom of the hearth 4 through the ignition device 2 to combust biomass; the heated secondary hot air enters the lower part of the hearth 4 through the lower secondary air 1-2 and the upper secondary air 1-3 to support combustion, strengthen and burn biomass in a grading way.

Claims (8)

1. The high-temperature and high-pressure steam boiler comprises a pure-burning biomass feeding system (1), an ignition device (2), an ash residue discharging device (3), a hearth (4), a separation material returning system (5), a wall-wrapping superheater (6), an air preheater (7), an environment-friendly interface (8), a water supply header (9), an economizer (10), a water supply distribution pipe (11), a boiler barrel (12), a centralized downcomer (13), a water screen downcomer (14), a water screen (15), a water screen eduction tube (16), a water-cooling steam guide tube (20), a steam eduction tube (21), a side wrapping wall (22), a front wrapping wall (23), a rear wrapping wall (24), a low-temperature superheater (25), a primary water-spraying desuperheater (26), a medium-temperature superheater (27), A secondary water spray desuperheater (28), a middle temperature screen superheater (29), a tertiary water spray desuperheater (30), a high temperature screen superheater (31) and a steam collection header (32); the method is characterized in that:

the pure-burning biomass feeding system (1) comprises lower-level secondary air (1-2), upper-level secondary air (1-3) and a plurality of feeding interfaces (1-1), wherein the upper-level secondary air (1-3) and the lower-level secondary air (1-2) are sequentially arranged at the lower part of a hearth (4) from top to bottom, the feeding interfaces (1-1) are arranged in front of a furnace, are positioned between the upper-level secondary air (1-3) and the lower-level secondary air (1-2) and are positioned at a negative pressure point at the lower part of the hearth, and the plurality of feeding interfaces (1-1) are sequentially arranged along the width direction of the hearth (4);

the ignition device (2) is positioned at the rear side of the bottom of the hearth (4), and the ignition device (2) is a natural gas ignition device;

the ash discharging device (3) comprises an ash discharging pipe (3-1) and a slag discharging pipe (3-2), wherein the ash discharging pipe (3-1) and the slag discharging pipe (3-2) are arranged at the bottom end of the hearth (4) and are communicated with the hearth (4);

a front water-cooling wall, a side water-cooling wall and a rear water-cooling wall are arranged in the hearth (4); the upper part of the hearth (4) is sequentially provided with a water-cooling screen (15), a medium-temperature screen superheater (29) and a high-temperature screen superheater (31) from top to bottom;

the separating and returning system (5) comprises a separator (5-1), a first inlet flue (5-2), a second inlet flue (5-3), a central cylinder (5-4), a turning chamber (5-5), a returning device (5-6) and a returning leg (5-7), wherein the first inlet flue (5-2) and one end of the second inlet flue (5-3) are communicated with each other, the first inlet flue (5-2) and the second inlet flue (5-3) are both arranged in a downward inclination manner, the downward inclination angle of the first inlet flue (5-2) is smaller than the downward inclination angle of the second inlet flue (5-3), the other end of the second inlet flue (5-3) is communicated with the upper end side wall of the separator (5-1), the lower end of the turning chamber (5-5) is communicated with the upper end of the separator (5-1), the central cylinder (5-4) is connected with the lower end of the steering chamber (5-5), the central cylinder (5-4) is positioned in the separator (5-1), and the material returning device (5-6) and the material returning legs (5-7) are positioned at the bottom of the separator (5-1);

the wall-wrapping superheater (6) comprises a side wall-wrapping superheater (22), a front wall-wrapping superheater (23) and a rear wall-wrapping superheater (24), and a medium-temperature superheater (27) and a low-temperature superheater (25) are arranged on the upper part of the wall-wrapping superheater (6) from top to bottom;

the economizer (10) and the air preheater (7) form a tail heating surface, the tail heating surface is positioned at the lower part of the wall-wrapped superheater (6), the economizer (10) and the air preheater (7) are sequentially arranged from top to bottom, the air preheater (7) comprises a higher-level air preheater (7-1), a middle-level air preheater (7-2), a lower-level air preheater (7-3) and an outlet flue (7-4), and the higher-level air preheater (7-1), the middle-level air preheater (7-2), the lower-level air preheater (7-3) and the outlet flue (7-4) are sequentially arranged from top to bottom;

the environment-friendly interface (8) comprises a denitration interface (8-1) and a desulfurization interface (8-2), the denitration interface (8-1) is arranged on a first inlet flue (5-2) of the separator (5-1), and the desulfurization interface (8-2) is arranged on a material returning leg (5-7) of the material returning device (5-6);

the upper side face of the separation material returning system (5) is communicated with the upper part of the hearth (4), the material returning legs (5-7) at the bottom of the separation material returning system (5) are communicated with the bottom of the hearth (4), and the turning chamber (5-5) at the top of the separation material returning system (5) is communicated with the inlet of the wall wrapping superheater (6).

2. The pure-biomass-fired environment-friendly circulating fluidized bed high-temperature high-pressure steam boiler according to claim 1, characterized in that: the cross section of the feeding interface (1-1) is rectangular, the cross section size of the feeding interface (1-1) is 800x800mm, the feeding interface (1-1) is arranged in a downward inclination mode, the downward inclination angle (a) of the feeding interface is 10-15 degrees, and a zero pressure point is arranged between the feeding interface (1-1) and the lower secondary air (1-2).

3. The pure-biomass-fired environment-friendly circulating fluidized bed high-temperature high-pressure steam boiler according to claim 1 or 2, characterized in that: the number of the ash discharge pipes (3-1) is three, the diameter of the ash discharge pipes (3-1) is phi 273mm, the number of the slag discharge pipes (3-2) is two, and the diameter of the slag discharge pipes (3-2) is phi 325 mm.

4. The pure-biomass-fired environment-friendly circulating fluidized bed high-temperature high-pressure steam boiler according to claim 3, characterized in that: the ash discharge pipes (3-1) are sequentially arranged along the width direction of the hearth (4), and a slag discharge pipe (3-2) is arranged between every two adjacent ash discharge pipes (3-1).

5. The pure-biomass-fired environment-friendly circulating fluidized bed high-temperature high-pressure steam boiler according to claim 1, 2 or 4, characterized in that: the downward inclination angle (b) of the first inlet flue (5-2) is 5 degrees, and the downward inclination angle (c) of the second inlet flue (5-3) is 10 degrees.

6. The pure-biomass-fired environment-friendly circulating fluidized bed high-temperature high-pressure steam boiler according to claim 5, characterized in that: the wall-wrapping superheater (6) is formed by enclosing a side wall-wrapping superheater (22), a front wall-wrapping superheater (23) and a rear wall-wrapping superheater (24).

7. The pure-biomass-fired environment-friendly circulating fluidized bed high-temperature and high-pressure steam boiler according to claim 1, 2, 4 or 6, characterized in that: the feeding interfaces (1-1) are uniformly distributed along the width direction of the hearth (4) in sequence.

8. The pure-biomass-fired environment-friendly circulating fluidized bed high-temperature high-pressure steam boiler according to claim 7, characterized in that: the air preheaters (7) are of horizontal tube structures, the number of the upper-level air preheaters (7-1) and the number of the middle-level air preheaters (7-2) are two, and the number of the lower-level air preheaters (7-3) are one.

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