CN108800097A - Improve boiler plant - Google Patents

Abstract

The present invention relates to improvement boiler plants, are related to a kind of for extending boiler especially chemical recovery boilers and thus optimization and simplifying the increased setting of its capacity and method.The object of the present invention is to provide a kind of boiler plant, can easily be transformed to increase efficiency of the boiler load without reducing combustion process, and be convenient for its Optimal Control.According to the present invention, the operation of boiler is extended in view of retaining and the relevant space of boiler so that side wall (3) can be moved, therefore increase the length of antetheca (2) and rear wall (4).The distance between the antetheca and rear wall are before substantially the same with enlarging after enlarging.

Description

Improve boiler plant

Technical field

The present invention relates to a kind of setting and method for extending boiler, the chemical recovery pots of the boiler especially pulp mill Stove, and it is especially the stove of the boiler, and therefore optimize and simplify the increase of its capacity.

Background technology

The stove of chemical recovery boilers for the black liquor that burns has antetheca, rear wall and side wall.Black ash liquor injector is one It is arranged on side wall in a height or several height.Multiple air scoops are arranged in several level heights on side wall, are used for Air is introduced into from air source in the stove.The flue gas generated in black-liquor combustion is guided and various heat transfer apparatus, overheat The water preheater (economizer) of device, boiler tube bundle and boiler contacts, therefore is present in the heat in the gas in heat transfer apparatus The form of or mixtures thereof middle flowing water, steam is withdrawn.Nose construction is arranged on the top of the stove for guiding the gas Stream.The steam is overheated by the superheater element of the top-hung.

Air usually inputs boiler with three kinds of different height：First time air inputs boiler bottom, and second of air exists The top of first time air height but is below fluid injector, and in order to ensure completely burned third time air is in fluid injector On.In general, air is either inputted from four all walls of boiler or only from two opposite side walls via several air scoops. More than three height for introducing air can also be set in the boiler.

The common feature of the new boiler device provided in recent years is that there is the new boiler of auxiliary device to be examined in Preliminary design Consider the increase of possible future capacity when necessary.Usually this is by the slot milling in the boiler of construction and to consider structure The structure of steel simultaneously increases the size of pipeline and there is auxiliary device enough capacity for boiler future load to realize.

Big range of capacity is led to the problem of in boiler operatiopn.About chemical recovery boilers, too big stove is in underload Under so that the sufficiently high molten bed tempertaure of holding and overheat appropriate is become very complicated, and too small stove leads to hotlist under high loads The danger that face blocks.These problems can be avoided by extending stove when the loading of the boiler changes.

So far, the enlarging inside chemical recovery boilers is real by the space for being preserved for relocating stove front and rear wall It is existing, thus side wall is extended.This leads to the increase of distance between antetheca and rear wall, this may cause asking for combustion process itself Topic.When combustion air is mainly inputted from antetheca and rear wall sky in gas arrangement, this is especially problematic.In recycling boiler furnace, Air runs through on second and third air height in combustion and air jet velocities are key factors.These parameters are logical It crosses and correct air port size is selected to optimize.Correct size depends on boiler load, appropriate under this boiler load Air capacity must be input to penetration distance appropriate via air scoop towards opposite wall.When arriving opposite wall in furnace enlargement It, must for the size of different boiler load air scoops if the quantity holding of air scoop is basically unchanged when distance increases So to consider.In such case, it is contemplated that the combustion process in boiler, can not achieve best result.It is typical empty Gas is arranged, wherein for example, second of air preferably only inputs from antetheca and rear wall in WO 02/081971 disclosed in WO It proposes.

Invention content

The purpose of the present invention is eliminating disadvantages mentioned above and providing a kind of improvement boiler plant, can easily be transformed to increase Boiler load is not suffered a loss so as to the efficiency of combustion process, and remains able to implement to control in the best way.The mesh of the present invention Also reside in compared with prior art technically by more it is simple faster in a manner of complete to extend.It is an object of the present invention to a kind of use In the setting of optimization special air height, especially it is used to optimize second of the chemical recovery boilers before and after furnace enlargement With third time air stream.

The present invention relates to a kind of boiler, especially a kind of chemical recovery boilers being made of antetheca, rear wall and two side walls. The present invention is characterized in that reserved the space for enlarging in terms of boiler, mode is mobile side wall, thus front and rear wall Length extend.

Therefore, vital idea of the invention is to prepare relocation one by extending front and rear wall when being transformed or building boiler A side wall.

Moreover, the present invention relates to a kind of methods in boiler, especially in the change being made of antetheca, rear wall and two side walls Learn recycling boiler in method, be characterized mainly in that the boiler is run in the first range of capacity first, thereafter to higher than Second range of capacity of the first range runs and the boiler is transformed by extending the boiler, and it is by mobile one to extend the boiler A side wall simultaneously correspondingly provides for the boiler that capacity increases required other device/facilities and transformation is completed.

The present invention provides a kind of improved method being ready for new boiler increase-volume.In particular, in some height, it is special It is not when the significant fraction on second and third height or substantially all air are inputted via front and rear wall, according to the present invention Method change in load and prodigious can keep optimum air supply and constant penetration distance to stove.

The distance between antetheca and rear wall do not change in enlarging.Since the additive air of enlarging needs is via along preceding The extended additional air scoop input of rear wall.This means that for before enlarging boiler load and enlarging after pass by one's way it is negative The size of lotus air scoop can optimize.In WO mentioned above is disclosed, in some air height or in certain air heights Air jet forms vertical row, can be by be supplied by the air mentioned by the amount of additional combustion air required for extending The required mode of system is obtained along the number that the additional vertical air scoop of the extension of front and rear wall arranges.

According to the present invention, one side wall of the boiler can be relocated in the schematic design phase of boiler plant and taken Measure.Easily disassembled holding platform is installed first along this dismountable side wall.Other devices are preferably provided at the construction Boiler plant inside other positions.In enlarging, steam drum extends and has necessary nozzle.In order to extend, Chi is melted One position is built into sufficiently large, or is the enlarging slot milling for melting pond future.Main header has must for what is extended The nozzle wanted.

The stove of boiler has width and depth.The width of stove refers to the horizontal length of furnace front wall, and depth refers to The horizontal length of furnace sidewall.So-called nose depth can remain unchanged, because the length of furnace sidewall is constant and thus The total depth of the stove is constant, which plays an important role flue gas stream is directed to stove top, and usually accounts for stove The 40-45% of sub- total depth.Wish that in the ratio of the front and back nose/sidewall of enlarging be same.

The optimization crossed in thermal element by top-hung steam velocity for ensuring that the superheater tube is suitably cooling, and And it on the other hand avoids excessive pressure from reducing and is very important.This is same by the number for increasing thermal element in the present invention When keep between the element lateral distance appropriate to realize.

Underload is avoided due to only being installed according to the present invention and extending relevant additional tube socket (tube panel) Too big and therefore inefficient hot surface is used on boiler tube bundle and in economizer part.This is also applied for overheating Device.

Yet another advantage of the present invention is that soot blower is only used on a wall before enlarging for smaller boiler capacity, because The size of boiler plant is not influenced for this scheme.Therefore initial outlay and maintenance work significantly reduce.

In the enlargement method (antetheca/rear wall transmission) of the prior art, four complete cross are at least needed in preceding (rear) wall To pipe weld seam, this causes hundreds of pipes/tube field welding (tube field weld) to be formed in most dangerous region and potentially oozed Leakage is dangerous.It is according to the present invention be arranged in upper furnace headers by the stringent welding of these requirements be reduced to only there are two.

In the arrangement in accordance with the invention, time for being stopped of boiler can be with when extending compared with the method for the prior art Shorten, because superheater, boiler tube bundle and economizer elements can be in private space pre-assemblies before being extended.According to The furnace enlargement of the present invention is very fast due to being easier site welding.

Description of the drawings

The present invention is further described in more detail below with reference to the accompanying drawings, wherein：

Fig. 1 is schematically illustrated present invention could apply to the side view of general chemical recovery boilers therein,

Fig. 2 schematically illustrates the furnace bottom sectional view from air height according to the present invention.

Specific implementation mode

Fig. 1 schematically illustrates chemical recovery boilers structure, has the stove 1 by being limited with downcomer wall：Antetheca 2, two A side wall 3 and rear wall 4 and the bottom wall 5 for also constituting water pipe.Combustion air is from several different height as first, second and Three air input in stove.There can also be other air heights.Waste liquid, such as black liquor are via between second and third air zone Nozzle 6 is introduced.In combustion, the molten bed from effluent is formed in the bottom 5 of stove, from here melt via mounted on The smelt spout 7 of furnace bottom exports.

The heat recovery surface of boiler, i.e. superheater 8 are located above stove, and the rear wall 4 of stove is then along stove top Superheater, boiler tube bundle 9 and economizer 10 accommodate hot surface, wherein the heat of the flue gas generated in a furnace is returned in the form of steam It receives.In the superheater, saturated vapor is converted into high-temperature vapour.In the boiler tube bundle 9 of boiler, boil to the water section of saturation temperature Steam is risen into, and before Jiang Shui is directed to the evaporation component 9 of boiler and crosses thermal part 8, water is in for feed water preheater 10 By smoke pre-heating.So-called nose reference numeral 14 is shown.

Water/vapour-cycling of boiler is occurred by means of Natural Circulation, thus is generated in boiler wall water pipe and bottom water pipe Water/steam mixture via manifold trunk flow up to relative to boiler transverse direction, i.e., along the direction of antetheca 2 be arranged steam Drum 11.Hot water flows to bottom concetrated pipe 13 from the steam drum via delivery pipe 12, and moisture is fitted on bottom water pipe and goes forward side by side one from here Walk water wall.

Fig. 2 shows the enlarging areas being retained in boiler, for repositioning a side wall 3 when an enlargement of the boiler is desired. The side wall is moved to the length of prolongation 2a, 4a of front/rear wall.Fig. 2 also schematically illustrates the air via air scoop 16 Jet stream 15, the number of air jet includes two jet streams on rear wall 4 and preceding in relatively low boiler capacity in the present arrangement Three jet streams on wall 2.The additive air needed in prolongation 2a, 4a of antetheca and rear wall by being arranged more air It mouthful 16a and is received in the enlargement via their air jet 15.In enlarging, existing air is had no need to change Mouth and the operation for flowing through their jet stream.

Be connected to the method for boiler it is known to those skilled in the art that, therefore do not retouched in more detail in this side It states.

Although in conjunction with being considered that most realistic most preferred embodiment describes the present invention, but it is to be understood that the present invention is not It is limited to the embodiment provided, but on the contrary, it is intended to cover belongs to the various modifications in the scope of the invention and in right With corresponding setting.For example, the application of the present invention is not limited to certain air settings, although working as the main of the air in certain height Part makes advantages of the present invention become particularly evident via antetheca and rear wall input.

Claims (1)

1. a kind of improvement boiler plant, the boiler plant are limited by antetheca, rear wall and two side walls, wherein by one mobile Side wall extends the boiler, which includes：

Antetheca and rear wall, the antetheca and rear wall each have the elongated portion for extending the boiler, wherein after enlarging The distance between the antetheca and rear wall are before substantially the same with enlarging；

Side wall, one of side wall can be moved relative to another side wall；

Device for conveying second air and the device for conveying third time air, mode is the master of second of air It is partly also defeated from the antetheca and the rear wall from the antetheca and the major part of rear wall input and third time air Enter；

Space for extending the boiler；With

Additive air mouth, the additive air needed for convey enlarging, the additive air mouth are arranged in the antetheca and described In the elongated portion of rear wall.