JP4074846B2

JP4074846B2 - Multi-tube boiler

Info

Publication number: JP4074846B2
Application number: JP2003333169A
Authority: JP
Inventors: 定和山田; 晴男野上
Original assignee: Takuma KK
Current assignee: Takuma KK
Priority date: 2003-09-25
Filing date: 2003-09-25
Publication date: 2008-04-16
Anticipated expiration: 2023-09-25
Also published as: JP2005098608A

Description

本発明は多管式ボイラの缶体構造の改良に関するものであり、水管相互の間隙部の伝熱面や燃焼室と反対側の水管の伝熱面を有効に活用することにより、ボイラの総合的な伝熱効率を高め、ボイラの小型化及び軽量化を可能とした多管式ボイラに関するものである。 The present invention relates to the improvement of the can structure of a multi-tube boiler, and by effectively utilizing the heat transfer surface of the gap between water tubes and the heat transfer surface of the water tube opposite to the combustion chamber, The present invention relates to a multi-tube boiler that can improve the heat transfer efficiency and reduce the size and weight of the boiler.

伝熱面積が５ｍ²以下・蒸気発生量が１００〜４００ｋｇ／Ｈ程度の多管式ボイラは、経済性や運転操作の簡便性とも相俟って事務所ビルや一般工場等で広く活用されている。
しかし、これ等の小型多管式ボイラに於いても、近年より一層の小型軽量化と省電力を図ることをユーザから強く要望されている。 Multi-tube boilers with a heat transfer area of 5 m ² or less and steam generation of about 100 to 400 kg / H are widely used in office buildings and general factories, etc., combined with economic efficiency and ease of operation. Yes.
However, even in these small multi-tube boilers, there has been a strong demand from users to further reduce size and weight and save power in recent years.

而して、前記ボイラの小型軽量化や省電力、燃料消費量の低減等を図るためには、燃焼ガス温度を高めると共に、燃焼用ファン動力の増加を来たすことなしにより高い伝熱効率を達成することが必須の要件となる。何故なら、伝熱効率は燃焼ガス温度と燃焼ガス流速に比例して向上するからである。 Thus, in order to reduce the size and weight of the boiler, save power, reduce fuel consumption, etc., the combustion gas temperature is increased, and high heat transfer efficiency is achieved without increasing the combustion fan power. This is an essential requirement. This is because the heat transfer efficiency is improved in proportion to the combustion gas temperature and the combustion gas flow velocity.

ところで、この種のボイラの缶体では、一般に複数本の水管を環状に配置し、この水管列の内側を燃焼室とすると共に、水管列の間にガス通路が形成されている。また、燃焼室では主に輻射による伝熱が行われ、ガス通路部では主に対流による伝熱が行われている。燃焼室の反対側の水管の伝熱面では、対流による伝熱が僅かに行なわれているが、あまり有効に活用されていないのが現状である。 By the way, in this type of boiler can, generally, a plurality of water pipes are annularly arranged, the inside of the water pipe row is used as a combustion chamber, and a gas passage is formed between the water pipe rows. Further, heat transfer is mainly performed by radiation in the combustion chamber, and heat transfer is mainly performed by convection in the gas passage portion. On the heat transfer surface of the water pipe on the opposite side of the combustion chamber, heat transfer by convection is carried out slightly, but the current situation is that it is not used effectively.

また、燃焼ガス温度の方も、サマールＮＯｘを抑制する必要から１２００℃以上に高めることは困難であり、どちらかと云えば低温燃焼が望まれる傾向にある。従って、水管の燃焼室側の伝熱面に於ける輻射伝熱による伝熱性は、現状以上に高めることが困難である。 Further, it is difficult to raise the combustion gas temperature to 1200 ° C. or higher because it is necessary to suppress samar NOx, and there is a tendency that low temperature combustion is desired. Therefore, it is difficult to improve the heat transfer property by radiant heat transfer on the heat transfer surface on the combustion chamber side of the water pipe more than the current level.

これに対して、燃焼ガスが燃焼室から燃焼ガス通路（煙道）へ向う部分の伝熱面（水管相互の間隙部や水管の燃焼室と反対側位置の伝熱面）は対流伝熱であるため、燃焼ガスの通過スピードを上昇させることによりその伝熱性を向上させ得る可能性がある。 On the other hand, the heat transfer surface of the part where the combustion gas goes from the combustion chamber to the combustion gas passage (flue) (the heat transfer surface on the opposite side of the water tube between the water tube and the combustion chamber) is convective heat transfer. Therefore, there is a possibility that the heat transfer property can be improved by increasing the passage speed of the combustion gas.

しかし、対流による伝熱性を高めるために燃焼ガスの流通速度を上げると、圧力損失が増加してファン性能が限界を越えたり、消費電力の増加を招くことになり、この点から対流による伝熱性の向上にも一定の制約がある。 However, if the combustion gas flow rate is increased to increase the heat transfer by convection, the pressure loss will increase and the fan performance will exceed the limit or increase the power consumption. From this point, the heat transfer by convection will be increased. There are certain restrictions on improvement.

更に、小型多管式ボイラ（例えばボイラ缶体の口径約８００ｍｍφ、高さ約１２００ｍｍ程度）であっても、蒸気温度が１７０℃〜１８０℃位いの高温になるため、缶体そのものが相当に熱膨脹をする。
そのため、燃焼ガス通路となる水管と水管の間隙（通常は１．２〜２ｍｍ）を缶体の製作時に厳密に管理しなければならないが、間隙の高精度な規制を要求すると缶体の製造コストが上昇することになる。
その結果、現実には前記間隙の不揃いに起因する燃焼ガスの偏流が発生し、総合的な伝熱効率の低下を来たしている。 Furthermore, even in a small multi-tube boiler (for example, a boiler can body having a diameter of about 800 mmφ and a height of about 1200 mm), the steam temperature is as high as about 170 ° C. to 180 ° C. Do thermal expansion.
For this reason, the gap between the water pipe and the water pipe (usually 1.2 to 2 mm) that serves as the combustion gas passage must be strictly controlled when manufacturing the can body. Will rise.
As a result, in reality, the combustion gas drifts due to the unevenness of the gaps, and the overall heat transfer efficiency is lowered.

一方、水管の燃焼室と反対側伝熱面に於ける対流による伝熱特性を高めることにより、上述の如き問題の解決を図ろうとする技術は、従前からも開発されている。 On the other hand, a technique for solving the above-described problems by enhancing heat transfer characteristics by convection on the heat transfer surface opposite to the combustion chamber of the water pipe has been developed.

図３及び図４はその一例を示すものであり、環状の上部管寄せ１と下部管寄せ２との間に水管３を約１．０〜１．５ｍｍの間隙４を置いて竪向きに配設し、ボイラ外壁５と環状の水管壁との間隙を燃焼ガス通路６とすると共に、水管３の燃焼ガス通路６側に約１．０〜１．５ｍｍの間隙４′を置いて熱伝達促進カバー１０を取り付けることにより、ボイラ缶体の主要部が形成されている。
尚、図３及び図４に於いて７は燃焼装置、８は燃焼室、９は水管端部の溶接部、１１は隔壁、１２は煙道、１３は煙突である。 FIG. 3 and FIG. 4 show an example of this, and the water pipe 3 is arranged in the vertical direction with a gap 4 of about 1.0 to 1.5 mm between the annular upper header 1 and the lower header 2. The combustion gas passage 6 is defined as a gap between the boiler outer wall 5 and the annular water pipe wall, and heat transfer is performed by placing a gap 4 'of about 1.0 to 1.5 mm on the combustion gas passage 6 side of the water pipe 3. By attaching the acceleration cover 10, the main part of the boiler can body is formed.
3 and 4 , 7 is a combustion apparatus, 8 is a combustion chamber, 9 is a welded portion at the end of the water pipe, 11 is a partition wall, 12 is a flue, and 13 is a chimney.

上記図３及び図４の缶体構造を備えた多管式竪型ボイラでは、燃焼室８内で発生した高温の燃焼ガスの熱が先ず輻射伝熱により水管３内の熱媒体に吸収されると共に、間隙４を通過する間に対流伝熱による熱交換をし、更に、間隙４′を通過する間に対流伝熱による熱交換をする。その結果、伝熱効率が向上して総合的な熱効率が上昇し、ボイラの大幅な小型軽量化が図れると云う利点を有している。 In the multi-tubular vertical boiler having the can structure shown in FIGS. 3 and 4 , the heat of the high-temperature combustion gas generated in the combustion chamber 8 is first absorbed by the heat medium in the water tube 3 by radiant heat transfer. At the same time, heat exchange is performed by convection heat transfer while passing through the gap 4, and heat exchange is also performed by convection heat transfer while passing through the gap 4 '. As a result, the heat transfer efficiency is improved, the overall heat efficiency is increased, and the boiler can be significantly reduced in size and weight.

しかし、図３及び図４の如き構成の多管式竪型ボイラにあっても、水管３の間隙４や熱伝達促進カバー１０と水管３との間隙４′を缶体製作上極めて厳密に管理する必要があり、必然的に缶体製作費の低減が図れないと云う問題がある。 However, even in the multitubular vertical boiler configured as shown in FIGS. 3 and 4 , the gap 4 between the water pipe 3 and the gap 4 ′ between the heat transfer promotion cover 10 and the water pipe 3 are very strictly controlled in manufacturing the can body. Therefore, there is a problem that the cost of manufacturing the can body cannot be reduced.

また、熱伝達促進カバー１０による伝熱性の向上も、主として間隙４′を流通する燃焼ガス流速の上昇による対流伝熱性の向上により得られるものであるため、結果として燃焼ガスの流通抵抗の増加による通風ファンの容量増加を必要とすることになり、電力費の増加等を招くと云う問題がある。 Further, the heat transfer enhancement by the heat transfer promotion cover 10 is also obtained mainly by the improvement of the convective heat transfer due to the increase in the flow velocity of the combustion gas flowing through the gap 4 ', resulting in an increase in the flow resistance of the combustion gas. There is a problem that the capacity of the ventilation fan needs to be increased, leading to an increase in power cost.

実公昭５３−４３９２１号No. 53-43921 特開昭５７−３１７０３号JP 57-31703

本発明は、従前の多管式ボイラに於ける上述の如き問題、即ち（イ）熱伝達カバーを用いて伝熱性の向上を図る場合には、缶体の製作コストの引下げが困難なこと、（ロ）燃焼用ファンの大型化や電力費の増加を招くこと、（ハ）熱膨脹による水管と熱伝達カバーの間の間隙の変化により燃焼ガスの偏流が生じ、伝熱性の向上が達成し難くなること等の問題を解決せんとするものであり、燃焼室から燃焼ガスが抜け出る水管相互間の間隙の下流部（燃焼室と反対側の位置）に、隣接する水管相互の間隔即ち燃焼ガスの通過スペースを正確に規制、確保することが可能な形態のセラミック輻射体を配設し、セラミック輻射体からの輻射熱を水管の燃焼ガス通路側の伝熱面に受熱させることにより、総合的な伝熱効率を高めることを可能とした多管式ボイラを提供するものである。 The present invention has a problem as described above in the conventional multi-tube boiler, that is, (i) when the heat transfer is improved by using the heat transfer cover, it is difficult to reduce the manufacturing cost of the can body. (B) Increase in the size of the combustion fan and increase in electric power costs, and (c) Change in the gap between the water pipe and the heat transfer cover due to thermal expansion causes combustion gas drift, making it difficult to improve heat transfer. In the downstream part of the gap between the water pipes where the combustion gas escapes from the combustion chamber (position opposite to the combustion chamber), the distance between adjacent water pipes, that is, the combustion gas A ceramic radiator in a form that can accurately regulate and secure the passage space is provided, and the radiant heat from the ceramic radiator is received by the heat transfer surface on the combustion gas passage side of the water pipe, thereby providing comprehensive transmission. Many that made it possible to increase thermal efficiency There is provided an expression boiler.

本願請求項１の発明は、水管列により形成した燃焼室から燃焼ガスを隣接する水管相互の隙間を通して燃焼室の外側の燃焼ガス通路へ流通させる構成の多管式ボイラに於いて、前記隣接する水管相互の間隙の燃焼ガス通路側の位置に、複数のセラミック球状体を縦向きに積層して成るセラミック輻射体を水管に沿って配置し、当該セラミック輻射体からの輻射熱を前記水管の燃焼ガス通路側の伝熱面により受熱する構成とし、又、セラミック輻射体を構成する各セラミック球状体を隣接する両水管の外壁面及び燃焼ガス通路を形成するボイラ外壁へ接触させ、当該セラミック輻射体により水管列を形成する水管相互の間隙を所定の間隙寸法に規制、保持するようにしたことを発明の基本構成とするものである。 The invention of claim 1 of the present application is a multi-tube boiler configured to circulate combustion gas from a combustion chamber formed by a water tube array to a combustion gas passage outside the combustion chamber through a gap between adjacent water tubes. A ceramic radiator formed by vertically laminating a plurality of ceramic spherical bodies is disposed along the water pipe at a position on the combustion gas passage side of the gap between the water pipes, and radiant heat from the ceramic radiator is transferred to the combustion gas of the water pipe. It is configured to receive heat by the heat transfer surface on the passage side, and each ceramic spherical body constituting the ceramic radiator is brought into contact with the outer wall surface of both adjacent water pipes and the outer wall of the boiler forming the combustion gas passage. The basic configuration of the invention is that the gap between the water pipes forming the water pipe row is regulated and held at a predetermined gap size .

本願発明に於いては、燃焼ガスによって加熱された高温のセラミック輻射体から放射された輻射熱が、水管相互の間隙部の伝熱面や燃焼室と反対側の水管の伝熱面に有効に受熱されることになり、総合的な熱効率が大幅に向上する。 In the present invention, the radiant heat radiated from the high-temperature ceramic radiator heated by the combustion gas is effectively received by the heat transfer surface of the gap between the water tubes and the heat transfer surface of the water tube opposite to the combustion chamber. As a result, the overall thermal efficiency is greatly improved.

また、本願発明に於いては、隣接する水管と水管との位置関係がセラミック輻射体によって正確に且つ確実に規制、保持されることになる。その結果、缶体製作時に、水管相互間の間隙の寸法精度を容易にしかも正確に所定の値（例えば２〜３ｍｍ）に保持することができ、缶体の製作費の大幅な削減が可能となる。 In the present invention, the positional relationship between adjacent water pipes is accurately and reliably regulated and held by the ceramic radiator. As a result, the dimensional accuracy of the gap between the water pipes can be easily and accurately maintained at a predetermined value (for example, 2 to 3 mm) at the time of manufacturing the can body, and the manufacturing cost of the can body can be greatly reduced. Become.

以下、図面に基づいて本発明の実施形態を説明する。
図１は、本発明の実施形態に係る小型多管式ボイラの縦断面概要図であり、図２はその横断面概要図である。 Hereinafter, describing the implementation embodiments of the present invention with reference to the accompanying drawings.
FIG. 1 is a schematic vertical cross-sectional view of a small multi-tube boiler according to an embodiment of the present invention , and FIG. 2 is a schematic cross-sectional view thereof .

図１及び図２に於いて、１は環状の上部管寄せ、２は環状の下部管寄せ、３は水管列を形成する水管、４は水管相互の間の間隙、５はボイラ外壁、６は燃焼ガス通路、７は燃焼装置、８は燃焼室、９は水管の溶接部、１２は煙道、１４は底部壁体、１５は煙道連結部、１８はセラミック輻射体、Ｇは燃焼ガス流であり、多管式ボイラの缶体構造そのものは公知であるため、ここではその詳細な説明を省略する。 1 and 2, 1 is an annular upper header, 2 is an annular lower header, 3 is a water tube forming a water tube row, 4 is a gap between the water tubes , 5 is a boiler outer wall, and 6 is a boiler outer wall. Combustion gas passage, 7 is a combustion device, 8 is a combustion chamber, 9 is a weld of a water pipe, 12 is a flue, 14 is a bottom wall, 15 is a flue connection, 18 is a ceramic radiator, G is a combustion gas flow Since the can structure of the multi-tubular boiler itself is publicly known, detailed description thereof is omitted here.

前記水管３は一定の間隙４を置いて円周上に複数本配列されており、水管列により所謂水管壁が形成されている。
また、水管壁の内部空間は燃焼室８となっており、天井壁に取付けした燃焼装置７によりバーナ燃焼が行なわれる。 A plurality of the water pipes 3 are arranged on the circumference with a certain gap 4, and a so-called water pipe wall is formed by the water pipe row.
The internal space of the water pipe wall is a combustion chamber 8, and burner combustion is performed by the combustion device 7 attached to the ceiling wall.

燃焼室８内で発生した燃焼ガスＧは、水管３相互の間の間隙４及び後述するセラミック輻射体１８と水管３の間の間隙を通って燃焼ガス通路６へ流入し、当該燃焼ガス通路６内を上昇して煙道１２から煙道連結部１５へ排出される。 Combustion gas G generated in the combustion chamber 8 flows through the period of clearance of the ceramic radiator 18 and a water pipe 3 to gap 4 and later during the water pipe 3 mutually to the combustion gas passage 6, the combustion gas passage 6 rises and is discharged from the flue 12 to the flue connection 15.

前記セラミック輻射体１８は、複数のセラミック球状体１８ａを縦向きに積層する構成としたものである。The ceramic radiator 18 has a structure in which a plurality of ceramic spherical bodies 18a are stacked vertically.
前記各セラミック球状体１８ａは燃焼ガス通路６の最小寸法よりも若干大きな直径の球体に形成されており、図２に示す如く、隣接する水管３・３とボイラ外壁５との間に縦向きに複数個積層されている。Each ceramic sphere 18a is formed into a sphere having a diameter slightly larger than the minimum dimension of the combustion gas passage 6, and is vertically disposed between the adjacent water pipes 3 and 3 and the boiler outer wall 5, as shown in FIG. A plurality of layers are stacked.

即ち、各セラミック球状体１８ａは両水管３・３及びボイラ外壁５との３点に接触しており、これによって各水管３・３のスペーサとしての機能と、伝熱性向上の機能とを果たすことになる。That is, each ceramic spherical body 18a is in contact with three points of both the water pipes 3 and 3 and the boiler outer wall 5, thereby fulfilling a function as a spacer of each water pipe 3 and 3 and a function of improving heat transfer. become.

前記燃焼室８内の高温燃焼ガスＧの熱は、輻射伝熱により水管壁の燃焼室８側の伝熱面から水管３内の熱媒体へ吸収される。
また、発生した燃焼ガスＧは、水管３と水管３の間の間隙４及び水管３とセラミック輻射体１８の間の間隙を通して燃焼ガス通路６内へ流入し、その間に燃焼ガスＧの熱は対流伝熱により水管３の燃焼ガス通路側の伝熱面へ吸収されると同時に、セラミック輻射体１８にも熱を与える。 The heat of the high-temperature combustion gas G in the combustion chamber 8 is absorbed into the heat medium in the water tube 3 from the heat transfer surface on the combustion chamber 8 side of the water tube wall by radiant heat transfer.
Further, the combustion gas G generated is through a period of gap water pipe 3 and the water tube gap 4 and the water pipes 3 between 3 and ceramic radiator 18 flows into the combustion gas passage 6, the combustion gas G in the meantime The heat is absorbed by the convection heat transfer to the heat transfer surface of the water tube 3 on the combustion gas passage side, and at the same time, heat is given to the ceramic radiator 18 .

即ち、セラミック輻射体１８は、水管３の間隙４を通して照射される燃焼室８からの輻射熱と、間隙４を流通する燃焼ガスＧの対流伝熱とによって加熱されると共に、吸収した熱を輻射熱の型で放射する。そして、セラミック輻射体１８から放射された熱は、水管３の燃焼ガス通路側の伝熱面へ与えられ、熱媒体に吸収される。 That is, the ceramic radiator 18 is heated by the radiant heat from the combustion chamber 8 irradiated through the gap 4 of the water pipe 3 and the convective heat transfer of the combustion gas G flowing through the gap 4 , and the absorbed heat is converted into radiant heat. Radiates with a mold. And the heat radiated | emitted from the ceramic radiator 18 is given to the heat transfer surface by the side of the combustion gas channel | path of the water pipe 3, and is absorbed by a heat medium.

上述のように、セラミック輻射体１８を設けることにより、燃焼ガスの熱が水管３の燃焼ガス通路側の伝熱面へ輻射熱の型で与えられことになり、従前の水管３の燃焼ガス通路側の伝熱面へ対流伝熱により伝熱される場合に比較して、熱の伝熱特性が大幅に向上し、総合的な熱効率が約２〜３％程度上昇する。 As described above, by providing the ceramic radiator 18 , the heat of the combustion gas is given to the heat transfer surface on the combustion gas passage side of the water pipe 3 in the form of radiant heat, and the conventional water pipe 3 side of the combustion gas passage is provided. Compared with the case where heat is transferred to the heat transfer surface by convection heat transfer, the heat transfer characteristics of heat are greatly improved, and the overall thermal efficiency is increased by about 2 to 3%.

尚、セラミック輻射体１８の原材料としては、高い熱輻射特性及び機械的強度を具備するものであれば如何なる材質のものであっても良く、本願の実施形態に於いては、アルミナを主体とするセラミックを使用している。 As the raw material of the ceramic radiator 18 may be of any material as long as having a high heat radiation characteristic and mechanical strength, is at the implementation form of the present application, the main component alumina Use ceramic.

本発明は、主として多管式ボイラへ適用されるものであるが、多管式ボイラのみならず、他の型式のボイラや熱交換器、コエノマイザ等へも適用することが出来る。 The present invention is mainly applied to a multi-tube boiler, but can be applied not only to a multi-tube boiler but also to other types of boilers, heat exchangers, coenomizers, and the like.

本発明の実施形態に係る小型多管式ボイラの縦断面概要図である。 It is a longitudinal section outline figure of a small multi-tube boiler concerning an embodiment of the present invention . 図１のＡ−Ａ視断面概要図である。It is an AA view cross-sectional schematic diagram of FIG. 従前の小型多管式竪型ボイラの断面概要図である。It is a cross-sectional schematic diagram of a conventional small multi-tubular vertical boiler. 図３のＡ−Ａ視断面概要図である。FIG. 4 is a schematic cross-sectional view taken along line AA in FIG. 3.

符号の説明Explanation of symbols

１は上部管寄せ、２は下部管寄せ、３は水管、４は水管相互の間の間隙、５はボイラ外壁、６は燃焼ガス通路、７は燃焼装置、８は燃焼室、９は溶接部、１２は煙道、１４は底部壁体、１５は煙道連結部、１８はセラミック輻射体、１８ａはセラミック球状体。 1 is an upper header, 2 is a lower header, 3 is a water tube, 4 is a gap between the water tubes , 5 is an outer wall of the boiler, 6 is a combustion gas passage, 7 is a combustion device, 8 is a combustion chamber, and 9 is a welded portion. , 12 flue 14 bottom wall, 15 flue connecting portion, 1 8 ceramic radiators, 18a are ceramic spheres.

Claims

水管列により形成した燃焼室から燃焼ガスを隣接する水管相互の隙間を通して燃焼室の外側の燃焼ガス通路へ流通させる構成の多管式ボイラに於いて、前記隣接する水管相互の間隙の燃焼ガス通路側の位置に、複数のセラミック球状体を縦向きに積層して成るセラミック輻射体を水管に沿って配置し、当該セラミック輻射体からの輻射熱を前記水管の燃焼ガス通路側の伝熱面により受熱する構成とし、又、セラミック輻射体を構成する各セラミック球状体を隣接する両水管の外壁面及び燃焼ガス通路を形成するボイラ外壁へ接触させ、当該セラミック輻射体により水管列を形成する水管相互の間隙を所定の間隙寸法に規制、保持するようにしたことを特徴とする多管式ボイラ。 In a multi-tube boiler configured to circulate combustion gas from a combustion chamber formed by a water tube array through a gap between adjacent water tubes to a combustion gas passage outside the combustion chamber, the combustion gas passage in the gap between adjacent water tubes A ceramic radiator formed by vertically stacking a plurality of ceramic spherical bodies is disposed along the water pipe at a position on the side, and radiant heat from the ceramic radiator is received by a heat transfer surface on the combustion gas passage side of the water pipe. In addition, the ceramic spherical bodies constituting the ceramic radiator are brought into contact with the outer wall surfaces of both adjacent water pipes and the boiler outer wall forming the combustion gas passage, and the water pipes forming the water pipe row by the ceramic radiators are mutually connected. A multi-tube boiler characterized in that the gap is regulated and held at a predetermined gap size .