JP3582844B2

JP3582844B2 - Heat medium circulation type heating furnace

Info

Publication number: JP3582844B2
Application number: JP26312993A
Authority: JP
Inventors: 榮男篠崎
Original assignee: Mitsubishi Kakoki Kaisha Ltd
Current assignee: Mitsubishi Kakoki Kaisha Ltd
Priority date: 1993-09-28
Filing date: 1993-09-28
Publication date: 2004-10-27
Anticipated expiration: 2019-10-27
Also published as: JPH0791743A

Description

【０００１】
【産業上の利用分野】
本発明は熱媒循環式加熱炉に関する。
【０００２】
【従来の技術】
加熱媒体を直火式加熱炉で加熱し、この加熱した加熱媒体（以下、熱媒という）を多管式の熱交換器に供給し、別の被加熱流体（以下、プロセス流体という）を加熱する方法はいくつかの分野で用いられている。この加熱方法は、プロセス流体が引火性が高い、あるいは高温で熱変性を起こし易い物質である等の理由により、プロセス流体を直火式加熱炉で直接には加熱できない場合に用いられることが多い。身近な例としては、温水ボイラの温水による可燃性ガスの加熱や、熱媒による有機化合物の加熱等があげられる。
【０００３】
この従来の熱媒を用いる加熱方式の具体例について、図面に基づいて説明する。図３は従来の熱媒加熱方式の系統図である。図において、２０は直火式の加熱炉であり、都市ガス，ＬＰＧ，灯油等の燃料をバーナ２２で燃焼し、その燃焼熱で加熱して加熱管２１内を流れる熱媒を加熱する。
【０００４】
２３は熱媒の循環ポンプであり、サービスタンク２４内の熱媒を管路２５を介して加熱炉２０内の加熱管２１に供給する。２６は加熱炉２０で加熱された熱媒を受け入れてプロセス流体を加熱する多管式の熱交換器である。すなわち加熱炉２０の加熱管２１を出る高温に加熱された熱媒は、管路２５を介して熱交換器２６の管内側に入り、管路２７を介して管外側に供給される低温側のプロセス流体と熱交換して加熱する。
【０００５】
【発明が解決しようとする課題】
以上説明した従来の熱媒を用いる加熱方式では、加熱した熱媒とプロセス流体の熱交換のために、加熱炉以外に多管式熱交換器の設置が必要であり、このため設備費が嵩むとともに、設備の設置面積も多く必要であるという問題がある。本発明は、以上の従来技術の問題を解消した熱媒加熱方式に用いられる新規なる構造の熱媒循環式加熱炉を提供することを課題とする。
【０００６】
【課題を解決するための手段】
上記課題を解決するための本発明の要旨とするところは、直火式の加熱炉の加熱管を二重管とし、内管側の入口ノズルと出口ノズルのそれぞれを、引火性が高い物質あるいは高温で熱変性を起こし易い物質である被加熱流体の管路に接続するとともに、外管側の入口ノズルと出口ノズルのそれぞれを、加熱媒体の循環装置の出口管路と入口管路とに接続し、外管側を循環して流れる加熱媒体を燃料の燃焼熱で加熱し、この加熱媒体と内管側の被加熱流体の対流伝熱により被加熱流体を加熱する構成としたことを特徴とする熱媒循環式加熱炉にある。
【０００７】
【作用】
直火式加熱炉の加熱管を二重管として、外管側に従来の加熱炉と同様に循環装置から供給される熱媒を通して循環する。燃料の燃焼による燃焼熱は外管の管壁に作用して外管側を流れる熱媒を加熱する。このようにして加熱された熱媒は、外管と内管の間を流れながら強制対流伝熱により内管側を流れる低温側の被加熱流体（プロセス流体）に内管壁を通して伝熱し加熱する。
【０００８】
このようにして、内管側を流れるプロセス流体は、外管側を流れる熱媒の強制対流伝熱により間接的に加熱されるので、プロセス流体は直火にさらされる危険もなく、また燃焼の輻射能で高温に過熱される外管壁に接触して熱変成をおこすおそれもない。
【０００９】
【実施例】
本発明の実施例について図面に基づいて説明する。図１は本発明の熱媒循環式加熱炉本体の縦断面図、図２は熱媒循環式加熱炉の熱媒循環系を含む装置の系統図である。図において、１は竪型円筒の加熱炉炉体であり、その内部には二重管式の加熱管２が炉壁に沿って同一円周上に上下端が接続されて立設される。４は炉床中央に上向きに設けられるバーナであり、都市ガス等の燃料を燃焼してその燃焼熱で加熱管２を加熱する。燃焼ガスは炉頂に設けられる煙突１５から大気に排出される。
【００１０】
５は熱媒の循環ポンプであり、サービスタンク６中の熱媒を管路７を介して加熱管２の外管側入口ノズル８に供給する。熱媒は外管側を流れながら、バーナ４の輻射能で加熱されて外管側出口ノズル９から出て管路７−１を経由してサービスタンク６に戻り循環される。
【００１１】
一方被加熱流体であるプロセス流体は、図示はされない供給手段によって管路１０を介して内管側入口ノズル１１に供給され、内管側を流れながら外管側を流れる高温熱媒の対流伝熱によって加熱され内管側出口ノズル１２を出て管路１０−１を経由してプロセス装置側に戻る。
【００１２】
１３は加熱管２の外管側を出る熱媒の温度調節計であり、プロセス流体の対流伝熱に好適な所定温度になるようバーナ４の燃料量をコントロール弁により調節して制御する。一方加熱管の内管側を出るプロセス流体の温度は、温度調節計１４によって管外側を流れる熱媒の循環流量を増減して制御する。すなわち循環流量を増加すれば、対流伝熱の熱伝達係数は増加して伝熱量は多くなり、反対に減小すれば、伝熱量は少なくなる。
【００１３】
以上の実施例においては、加熱炉の型式が竪型円筒の場合について説明したが、本発明はこれに限定されるものでなく、引火性が高い物質あるいは高温で熱変性を起こし易い物質である被加熱流体を直火式の加熱炉で加熱するにあたり、加熱管を二重管とし、内管側を被加熱流体が流通し、外管側を熱媒体が循環流通する構成にできるものであれば他の型式の加熱炉例えば横型等にも適用できる。
【００１４】
【発明の効果】
以上の構成と作用を有する本発明によれば、熱媒とプロセス流体の熱交換のための熱交換器の設置は必要がないので、設備費を安価にできるとともに、設置面積を節減できる効果が得られる。
【図面の簡単な説明】
【図１】熱媒循環式加熱炉本体の縦断面図。
【図２】熱媒循環式加熱炉の熱媒循環系を含む装置の系統図。
【図３】従来の熱媒加熱方式の系統図。
【符号の説明】
１；加熱炉炉体、２；二重管式加熱管、３；炉壁、４；バーナ、５；熱媒ポンプ、６；サービスタンク、７；管路、８；外管側入口ノズル、９；外管側出口ノズル、１０；管路、１１；内管側入口ノズル、１２；内管側出口ノズル、１３；温度調節計、１４；温度調節計、１５；煙突。[0001]
[Industrial applications]
The present invention relates to a heating medium circulation heating furnace.
[0002]
[Prior art]
A heating medium is heated in a direct-fired heating furnace, and the heated heating medium (hereinafter, referred to as a heating medium) is supplied to a multi-tube heat exchanger to heat another fluid to be heated (hereinafter, referred to as a process fluid). This method is used in several fields. This heating method is often used when the process fluid cannot be directly heated by a direct-fired heating furnace, because the process fluid has a high flammability or is a substance that easily undergoes thermal denaturation at high temperatures. . Examples of familiar examples include heating of combustible gas by hot water of a hot water boiler, and heating of organic compounds by a heating medium.
[0003]
A specific example of this conventional heating method using a heat medium will be described with reference to the drawings. FIG. 3 is a system diagram of a conventional heating medium heating system. In the figure, reference numeral 20 denotes a direct-fired heating furnace, which burns fuel such as city gas, LPG, and kerosene by a burner 22 and heats the combustion medium to heat a heating medium flowing through a heating pipe 21.
[0004]
A heat medium circulation pump 23 supplies the heat medium in the service tank 24 to the heating pipe 21 in the heating furnace 20 through a pipe 25. Reference numeral 26 denotes a multitubular heat exchanger that receives the heat medium heated by the heating furnace 20 and heats the process fluid. That is, the heat medium heated to a high temperature exiting the heating tube 21 of the heating furnace 20 enters the inside of the heat exchanger 26 via the pipe 25 and is supplied to the outside of the pipe via the pipe 27 on the low temperature side. Heats by exchanging heat with the process fluid.
[0005]
[Problems to be solved by the invention]
In the heating method using the conventional heat medium described above, it is necessary to install a multi-tube heat exchanger in addition to the heating furnace for exchanging heat between the heated heat medium and the process fluid, which increases equipment costs. In addition, there is a problem that a large installation area of the equipment is required. An object of the present invention is to provide a heating medium circulation type heating furnace having a novel structure used in a heating medium heating method that has solved the above-described problems of the conventional technology.
[0006]
[Means for Solving the Problems]
The gist of the present invention for solving the above-mentioned problem is that the heating tube of the direct-fired heating furnace is a double tube, and each of the inlet nozzle and the outlet nozzle on the inner tube side is made of a highly flammable substance or Connect to the pipe of the fluid to be heated, which is a substance that easily undergoes thermal denaturation at high temperatures, and connect the inlet nozzle and outlet nozzle on the outer pipe side to the outlet pipe and inlet pipe of the heating medium circulation device. and the heating medium flowing circulating the outer tube side heat in the combustion heat of the fuel, and characterized in that a structure for heating the heated fluid by convection heat transfer of the heated fluid in the heating medium and the inner tube side In a heating medium circulation type heating furnace.
[0007]
[Action]
The heating tube of the direct-fired heating furnace is a double tube, and circulates through the heat medium supplied from the circulation device to the outer tube side in the same manner as the conventional heating furnace. The heat of combustion due to the combustion of the fuel acts on the tube wall of the outer tube to heat the heat medium flowing on the outer tube side. The heat medium thus heated is transferred between the outer tube and the inner tube by forced convection heat transfer, and is transferred to the low-temperature-side heated fluid (process fluid) flowing on the inner tube side through the inner tube wall to be heated. .
[0008]
In this way, the process fluid flowing on the inner tube side is indirectly heated by the forced convection heat transfer of the heat medium flowing on the outer tube side, so that the process fluid does not have a danger of being exposed to a direct flame, and the combustion fluid is not heated. There is no danger of thermal denaturation due to contact with the outer tube wall which is heated to a high temperature by radiation.
[0009]
【Example】
An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of a heating medium circulation type heating furnace main body of the present invention, and FIG. 2 is a system diagram of an apparatus including a heating medium circulation system of the heating medium circulation type heating furnace. In the figure, reference numeral 1 denotes a vertical cylindrical heating furnace body, in which a double-tube heating tube 2 is erected on the same circumference along the furnace wall with its upper and lower ends connected. Reference numeral 4 denotes a burner provided upward in the center of the hearth, which burns fuel such as city gas and heats the heating tube 2 with the heat of combustion. The combustion gas is discharged to the atmosphere from a chimney 15 provided on the furnace top.
[0010]
Reference numeral 5 denotes a circulation pump for the heat medium, which supplies the heat medium in the service tank 6 to the outer tube side inlet nozzle 8 of the heating tube 2 through the pipe 7. The heat medium is heated by the radiant power of the burner 4 while flowing on the outer tube side, exits from the outer tube side outlet nozzle 9, returns to the service tank 6 via the pipe line 7-1, and is circulated.
[0011]
On the other hand, the process fluid as the fluid to be heated is supplied to the inner pipe side inlet nozzle 11 via the pipe 10 by a supply means (not shown), and the convective heat transfer of the high-temperature heat medium flowing on the outer pipe side while flowing on the inner pipe side. Then, it is heated and exits the inner tube side outlet nozzle 12 and returns to the process device side via the line 10-1.
[0012]
Reference numeral 13 denotes a temperature controller for the heat medium that exits the outer tube side of the heating tube 2, and controls the fuel amount of the burner 4 by a control valve so as to reach a predetermined temperature suitable for convective heat transfer of the process fluid. On the other hand, the temperature of the process fluid exiting the inner tube side of the heating tube is controlled by increasing or decreasing the circulating flow rate of the heat medium flowing outside the tube by the temperature controller 14. That is, if the circulation flow rate is increased, the heat transfer coefficient of convective heat transfer is increased and the amount of heat transfer is increased. Conversely, if the amount is reduced, the amount of heat transfer is reduced.
[0013]
In the above embodiments, the case where the type of the heating furnace is a vertical cylinder has been described. However, the present invention is not limited to this, and is a substance having a high flammability or a substance which easily undergoes thermal denaturation at a high temperature. When heating the fluid to be heated in a direct-fired heating furnace, the heating pipe may be configured as a double pipe, in which the fluid to be heated flows on the inner pipe side and the heat medium circulates and flows on the outer pipe side. For example, the present invention can be applied to other types of heating furnaces such as a horizontal heating furnace.
[0014]
【The invention's effect】
According to the present invention having the above configuration and operation, it is not necessary to install a heat exchanger for heat exchange between the heat medium and the process fluid, so that equipment costs can be reduced and the installation area can be reduced. can get.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a heating medium circulation heating furnace main body.
FIG. 2 is a system diagram of an apparatus including a heating medium circulation system of a heating medium circulation heating furnace.
FIG. 3 is a system diagram of a conventional heating medium heating method.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1; Heating furnace body, 2; Double tube type heating tube, 3; Furnace wall, 4; Burner, 5; Heat medium pump, 6; Service tank, 7; Pipe line, 8; Outer pipe side outlet nozzle, 10; pipe line, 11; inner pipe side inlet nozzle, 12; inner pipe side outlet nozzle, 13; temperature controller, 14; temperature controller, 15;

Claims

直火式の加熱炉の加熱管を二重管とし、内管側の入口ノズルと出口ノズルのそれぞれを、引火性が高い物質あるいは高温で熱変性を起こし易い物質である被加熱流体の管路に接続するとともに、外管側の入口ノズルと出口ノズルのそれぞれを、加熱媒体の循環装置の出口管路と入口管路とに接続し、外管側を循環して流れる加熱媒体を燃料の燃焼熱で加熱し、この加熱媒体と内管側の被加熱流体の対流伝熱により被加熱流体を加熱する構成としたことを特徴とする熱媒循環式加熱炉。The heating pipe of the direct-fired heating furnace is a double pipe, and each of the inlet nozzle and the outlet nozzle on the inner pipe side is a pipeline of a fluid to be heated, which is a substance having high flammability or a substance which is apt to undergo thermal denaturation at high temperatures In addition, the inlet nozzle and the outlet nozzle on the outer tube side are connected to the outlet line and the inlet line of the heating medium circulating device , and the heating medium circulating on the outer tube side flows through the combustion of fuel. it was heated by the heat, a heating medium circulation type heating furnace, characterized in that the arrangement for heating the heated fluid by convection heat transfer of the heated fluid in the heating medium and the inner pipe side.