JPS6035968A - Sensible heat recovering method of high temperature gas - Google Patents

Abstract

PURPOSE:To efficiently recover the sensible heat of high temperature gas by converting the sensible heat of the high temperature gas into that of thermal medium, and further converting it by a thermoelectric element into electric energy. CONSTITUTION:High temperature gas 10 applies considerable portion of sensible heat of itself via a heat exchanger 12 to thermal medium 13, the temperature of itself is decreased in the amount corresponding to the given quantity of heat, and exhausted by a blower 11 out of a system. The medium 13, to which the sensible heat of the gas 10 is applied, applies its sensible heat to a thermoelectric generator 15. The medium 13 itself decreases it temperature to the original value, supplies via a pump 14 to the exchanger 12, and sensible heat is applied again from the gas 10. The thermoelectric element of the generator 15 generates electric power in response to the thermoelectric capacity. Coolant is circulated through a pump 17 and a cooling tower 18 to the generator 15. The generated power is produced to an electric line 19, and converted to AC via a DC/AC exchanger 20.

Description

【発明の詳細な説明】 （産業上の利用分野） 本発明は、気体顕熱を熱電発電によって電力として回収
する気体の顕熱回収方法に関するものである。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for recovering gaseous sensible heat in the form of electric power through thermoelectric power generation.

（従来技術） 非常に多くの産業排熱が気体の顕熱として排出されてお
Ｑ、特に鉄鋼業においてはその量も膨大であり、排ガス
の顕熱の回収は極めて重要である。(Prior Art) A very large amount of industrial waste heat is emitted as gaseous sensible heat, Q, and the amount is especially enormous in the steel industry, so recovery of sensible heat from waste gas is extremely important.

ところで熱を直接電気に変換する熱電発電は、良質なエ
ネルギーへの変換、顕熱回収工程の簡素化、発電設備の
小型化などの利点があ多重要な排熱回収の手段であり、
従来より、第１図に示すような高温の気体１の流路２の
中に受熱器３を取シつけ、受熱器３の背面に熱電素子群
４の高温接合部５を接着Ｉ２、一方熱電累子群４の低温
接合部６を放熱器７の背面に接着し、放熱器７を低温流
体８の流路９の中に配置した構造の熱電発電装置が気体
を熱源とした熱電発電に用いられている。By the way, thermoelectric power generation, which directly converts heat into electricity, is an important means of waste heat recovery with many advantages such as conversion into high-quality energy, simplification of the sensible heat recovery process, and miniaturization of power generation equipment.
Conventionally, a heat receiver 3 is installed in a flow path 2 of a high-temperature gas 1 as shown in FIG. A thermoelectric power generation device having a structure in which the low-temperature joint 6 of the separator group 4 is bonded to the back of a radiator 7 and the radiator 7 is placed in a flow path 9 of a low-temperature fluid 8 is used for thermoelectric power generation using gas as a heat source. It is being

しかしながら、産業排ガスの顕熱回収に上記の従来方法
を利用しようとした場合、以下に列挙するような欠点が
ある。However, when attempting to utilize the above conventional method for sensible heat recovery from industrial exhaust gas, there are drawbacks as listed below.

■　発電効率を上げるためには熱電素子群４の高温接合
部５と低温接合部６との間にできるだけ大きな温度差を
つける必要がある。しかし、一般に気体の境膜熱伝達係
数は高々数１０　ｋｍ／　ｍ２ｈｒ℃であシ、気体温度
が低い場合は気体１から受熱器３への伝熱が律速となっ
て熱電素子群４の高温接合部５と低温接合部６の温度差
は大きくとれない・したがって発電効率ならびに発電電
力が小さくなるＯ ■　燃焼排ガス等の一般の産業排ガスはダストを含んで
おシ、受熱器３の表面に付着して熱抵抗となりガスから
熱電素子への伝熱を悪化させる。■ In order to increase power generation efficiency, it is necessary to create as large a temperature difference as possible between the high temperature junction 5 and the low temperature junction 6 of the thermoelectric element group 4. However, in general, the film heat transfer coefficient of a gas is at most several 10 km/m2hr°C, and when the gas temperature is low, the rate of heat transfer from the gas 1 to the heat receiver 3 becomes rate-determining, resulting in high-temperature bonding of the thermoelectric element group 4. The temperature difference between the section 5 and the low-temperature junction section 6 cannot be large. Therefore, the power generation efficiency and the generated power will be reduced.General industrial exhaust gas such as combustion exhaust gas contains dust and adheres to the surface of the heat receiver 3. This creates thermal resistance and worsens heat transfer from the gas to the thermoelectric element.

（発明の目的） 本発明は、上記のような従来方法の欠点を解消し、熱電
素子の高温接合部と低温接合部の温度差を大きくとるこ
とができるようにした気体顕熱の熱電発電による回収方
法を提供するものである。(Objective of the Invention) The present invention solves the drawbacks of the conventional methods as described above, and utilizes thermoelectric power generation using gas sensible heat, which makes it possible to increase the temperature difference between the high-temperature junction and the low-temperature junction of a thermoelectric element. It provides a collection method.

（発明の構成及び作用） 本発明の要旨とするところは高温ガスの顕熱を液状の熱
媒体の顕熱に変換し、その熱媒体の顕熱を熱電素子によ
って電気エネルギーに変換して回収することを特徴とす
る高温ガスの顕熱回収方法にある。(Structure and operation of the invention) The gist of the present invention is to convert the sensible heat of a high-temperature gas into the sensible heat of a liquid heat medium, and to convert the sensible heat of the heat medium into electrical energy using a thermoelectric element and recover it. A method for recovering sensible heat from high-temperature gas is characterized by the following.

本発明を実施する設備の概略を第２図によシ説明する。The outline of the equipment for implementing the present invention will be explained with reference to FIG.

１０は発生源からの高温ガスで、ブロワ−１１により発
生源から吸引されて熱交換器１２に供給され、熱交換器
１２は高温がス１０と、該熱交換器内を通る熱媒体１３
との熱交換を行う。10 is a high temperature gas from a generation source, which is sucked from the source by a blower 11 and supplied to a heat exchanger 12;
exchange heat with the

１４は熱媒体１３を熱交換器１２と熱電発電装置１５の
間を循環させるポン１である。一方１６は冷却水で７」
ヒンジＩ７にＪ：って熱電発電装置１５と冷水堝１８の
間全（１１１ｉ［−ｆるようになっている。Reference numeral 14 denotes a pump 1 that circulates the heat medium 13 between the heat exchanger 12 and the thermoelectric generator 15. On the other hand, 16 is 7 for cooling water.
The hinge I7 is arranged so that J: extends between the thermoelectric generator 15 and the cold water basin 18 (111i[-f).

１９ｄ′岨気醒路で、２〔）は直交変換器である。In the 19d' diversion path, 2[) is an orthogonal transformer.

この実施装置４による本発明の実施態様を説明する。An embodiment of the present invention using this implementation device 4 will be described.

高温ガス１０目熱交換器１２でそれ自体の七する顕熱の
相当な部分を熱媒体１３に与え、与えた熱量に相当−「
るだけそれ自体の温度を低下して、ブロワ・−１１によ
って系外に排出される。高温ガス１０の顕熱を−りえら
れた熱媒体１３はその顕熱を熱軍発１ｄ装置１５の熱電
素子に与え、熱媒１杢１：３自身は温度を元に下げてポ
ンプ１４によって熱交換器１２に供給され、再び高温ガ
スより顕熱を与えられる。熱電１発電装置１ｆ１５の熱
電素子はその熱電能に応じた市、力を発電する。この熱
電素子に与えられた熱のりち発電に使われなかった分は
熱電発電装ｆｉ！１１５において冷却水１６によって奪
われる・熱を奪った冷却水１６は温度が上昇するので冷
水屹・１８ではじめの水温まで冷却してポン７”１７で
山び熱′目も発電装置】５に供給される。熱電発電装置
の熱電素子によって発電された電力は、電力取出し端子
を通じて電気線路１９に取り出され、直交変換器２０に
よって交流に変換して一般の電力系統へ供給される。The high-temperature gas heat exchanger 12 gives a considerable portion of its own sensible heat to the heating medium 13, and the amount of heat equivalent to the given heat is -
It is discharged from the system by the blower-11. The heating medium 13 that has recovered the sensible heat of the high-temperature gas 10 gives the sensible heat to the thermoelectric element of the thermoelectric generator 1d device 15, and the heating medium 1:3 itself lowers its temperature and generates heat by the pump 14. The gas is supplied to the exchanger 12 and given sensible heat by the high temperature gas again. The thermoelectric element of the thermoelectric generator 1f15 generates power according to its thermoelectric capacity. The heat given to this thermoelectric element that is not used for power generation is used as a thermoelectric generator fi! At 115, the temperature of the cooling water 16 that has been taken away by the cooling water 16 rises, so it is cooled down to the initial water temperature at 18, and the heat is increased at 17. The electric power generated by the thermoelectric element of the thermoelectric generator is taken out to the electric line 19 through the power extraction terminal, converted to alternating current by the orthogonal converter 20, and then supplied to the general power system.

熱媒体１３としては、例えばＮａ２Ｃｏ、　ｌ　ＮａＦ
等の溶融塩やアルキルジフェニール等の有機熱媒体を用
いることができる。熱電発電装置１１５内における熱媒
体１３の境膜熱伝達係数は１５００〜５０００　ｋｍ／
ｍ”ｈｒ　Ｃあシ、ガスの場合の数１０ｋｍ／ｍ”ｈｒ
’ｃの５０〜１００倍である。したがって、ガスの場合
のように熱媒体から熱電素子の受熱面への伝熱が律速と
なりて熱電素子の高温接合部と低温接合部の温度差が著
しく小さくなることはなく、充分な温度差を取ることが
可能である。また、熱媒体は閉じた流路の中を循環して
いるので、熱電素子の受熱面を汚してその伝熱能力を悪
化させることはない。As the heat medium 13, for example, Na2Co, lNaF
A molten salt such as or an organic heat carrier such as alkyldiphenyl can be used. The film heat transfer coefficient of the heat medium 13 in the thermoelectric generator 115 is 1500 to 5000 km/
m"hr C foot, several 10km/m"hr in case of gas
It is 50 to 100 times that of 'c. Therefore, unlike in the case of gas, the rate of heat transfer from the heat medium to the heat receiving surface of the thermoelectric element becomes rate-determining, and the temperature difference between the high-temperature junction and the low-temperature junction of the thermoelectric element does not become significantly small. It is possible to take. Further, since the heat medium circulates in a closed flow path, it does not pollute the heat receiving surface of the thermoelectric element and deteriorate its heat transfer ability.

（実施例） 本発明を一片の加熱炉の排ガスに実施した例を説明する
。排ガスの温度は５００’Ｃで、その発生（５） 敬は約ＩＱ　Ｎｙｎ”／ｈｒである。煙道の中に排ガス
と熱媒体との熱交換器を糸目み込み、熱交換後の排ガス
温度を２００℃にし７た。熱媒体にはアルキルジフェニ
ール（曲品名；サーム５ｓｏｏ）？使用し、１８０℃で
熱交換器に入り、３００℃で出た。熱媒体の循環量は約
１　（ｌ　Ｏｔ／ｈｒであった。〔７たがって、熱電発
電装置に対し、ては３００℃の熱媒体が供給された。冷
却水の温度は水あかの発生を迎えるため５０℃以下に１
また。熱電発電装置は熱媒体の流路と冷却水の流路とが
直交する構造を有し、熱媒体の流路と冷却水の流路の間
にカルコダン化合物からなる熱ｖＭ素子を並べてはさん
だ構成とした。この熱電素子ｄ素子内の温度差が２００
℃のとき発電効率１１，６％、発電ｈトカ１５ｋＷ／ｍ
”となる性能を有する。(Example) An example in which the present invention is applied to a piece of exhaust gas from a heating furnace will be described. The temperature of the exhaust gas is 500'C, and the temperature of its generation (5) is approximately IQ Nyn''/hr.A heat exchanger between the exhaust gas and the heat medium is inserted into the flue, and the exhaust gas temperature after heat exchange is was heated to 200°C. Alkyldiphenyl (song name: Therm 5soo) was used as the heating medium, and it entered the heat exchanger at 180°C and exited at 300°C. The circulating amount of the heating medium was approximately 1 (l). [7] Therefore, a heat medium of 300°C was supplied to the thermoelectric generator.The temperature of the cooling water was kept below 50°C due to the formation of water scale.
Also. The thermoelectric power generation device has a structure in which a heat medium flow path and a cooling water flow path are orthogonal to each other, and thermal vM elements made of a chalcodan compound are arranged and sandwiched between the heat medium flow path and the cooling water flow path. And so. The temperature difference within this thermoelectric element d is 200
℃, power generation efficiency is 11.6%, power generation h is 15kW/m
” has the performance.

この実施例の結果？第１表に示した。The result of this example? It is shown in Table 1.

ま九、比較のために、第３図に示すように排ガス煙道の
中に熱電発電装ｆ１３２を組み込んで、直接排ガス３０
から熱ηｆ素子の高温接合部に受熱する従来の方法を実
施した。図において、３１ｉ、１．プ（６） ロワー、３３は冷却水、３４はポンプ、３５は冷却塔、
３６は電気線路、３７は直交変換器である。For comparison, a thermoelectric generator F132 was installed in the exhaust gas flue as shown in Figure 3, and the exhaust gas 30
A conventional method of receiving heat from the high temperature junction of the thermal ηf element was carried out. In the figure, 31i, 1. (6) Lower, 33 is cooling water, 34 is pump, 35 is cooling tower,
36 is an electric line, and 37 is an orthogonal converter.

排プｆスの清、性状、冷却水の温度は前記の実施例と同
じである。この実施例の結果も第１表に示したＯ 第　１　表 （発明の効果） 第１表に示す」：うに、従来法と対比して本発明の効果
は顕著に優才している。発電効率は従来法の約５．７倍
に高まり、発電量は排ガスから熱媒体へ、熱媒体から′
鑞力へという２回の変換にもかかわらず従来法の約５．
４倍と増大している。The quality and properties of the waste water and the temperature of the cooling water are the same as in the previous embodiment. The results of this example are also shown in Table 1. Table 1 (Effects of the Invention) Table 1 shows that the effects of the present invention are significantly superior to those of the conventional method. The power generation efficiency is approximately 5.7 times higher than that of the conventional method, and the amount of power generated is increased from the exhaust gas to the heat medium and from the heat medium to
Despite the two-time conversion to force, the conventional method is about 5.
It has increased four times.

すなわち９丁、米寿法では、ガスの境膜熱伝達係数が小
さいためにノｆスと受熱器の間に大きな温度差が生じ、
熱電素子の高温接合部と低温接合部の間には２３℃程度
の小さな温度差しか生せず、そのために発′区′ｉ′１
発電効率共極めて小さい。−力木発明の方法によると熱
媒体の境膜熱伝達係数がガスの１００倍近くあるので、
熱媒体と受熱器の間の温度差は小さく、熱を素子の高温
接合部と低温接合部の間に１５０℃程度の温度差を得る
ことができ、発電量１発電効率とも格段に向上すること
ができる。In other words, in the 9th generation and Beiju methods, a large temperature difference occurs between the nozzle and the heat receiver due to the small film heat transfer coefficient of the gas.
There is only a small temperature difference of about 23°C between the high-temperature junction and the low-temperature junction of the thermoelectric element.
Power generation efficiency is extremely low. - According to the method invented by Riki, the film heat transfer coefficient of the heat medium is nearly 100 times that of gas, so
The temperature difference between the heat medium and the heat receiver is small, and it is possible to obtain a temperature difference of about 150 degrees Celsius between the high-temperature junction and low-temperature junction of the element, significantly improving both power generation and power generation efficiency. Can be done.

以上の如く本発明は産業排ガスの顕熱を直接電気エネル
ギーに変換するにあたシ、その効率を著しく高めること
ができるので、産業上稗益するところが極めて大である
。As described above, the present invention can significantly improve the efficiency of directly converting the sensible heat of industrial exhaust gas into electrical energy, and therefore has great industrial benefits.

【図面の簡単な説明】[Brief explanation of drawings]

第１図は従来より高温ガス用に使われている熱電発電装
置の断面を模式的に示す説明図、第２図は本発明の高温
ガスの顕熱回収方法の具体的な説明図、第３図は従来の
高温ガスの顕熱回収方法の説明図である。 ｌ・・・高温ガス、２・・・高温ガスの流路、３・・・
受熱（９） 器、４・・・熱電素子群、５・・・高温接合部、６・・
・低温接合部、７・・・放熱器、８・・・低温流体、９
・・・低温流体の流路、１０・・・高温ガス、１１・・
・プロワ−１１２・・・熱交換器、１３・・・熱媒体、
１４・・・ポンプ、１５・・・熱電発電装置、１６・・
・冷却水、１７・・・ポンプ、１８・・・冷却塔、１９
・・・電気線路、２０・・・直交変換器、３０・・・高
温ガス、３１・・・ブロワ−１３２・・・熱電発電、装
置、３３・・・冷却水、３４・・・ポンプ、３５・・・
冷却塔、３６・・・電気線路、３７・・・直交変換器。 （１０） φニジ −３９０−Fig. 1 is an explanatory diagram schematically showing a cross section of a thermoelectric power generation device conventionally used for high-temperature gas, Fig. 2 is a concrete explanatory diagram of the sensible heat recovery method for high-temperature gas of the present invention, and Fig. 3 The figure is an explanatory diagram of a conventional method for recovering sensible heat from high-temperature gas. l...High temperature gas, 2...High temperature gas flow path, 3...
Heat receiving (9) vessel, 4... thermoelectric element group, 5... high temperature junction, 6...
・Low temperature junction, 7... Heat sink, 8... Low temperature fluid, 9
...low-temperature fluid flow path, 10...high-temperature gas, 11...
- Prower 112... heat exchanger, 13... heat medium,
14... Pump, 15... Thermoelectric generator, 16...
・Cooling water, 17...Pump, 18...Cooling tower, 19
...Electric line, 20...Orthogonal converter, 30...High temperature gas, 31...Blower-132...Thermoelectric power generation, device, 33...Cooling water, 34...Pump, 35 ...
Cooling tower, 36... Electric line, 37... Orthogonal converter. (10) φ Niji-390-

Claims (1)

【特許請求の範囲】[Claims] 高温ガスの顕熱を液状の熱媒体の顕熱に変換し、その熱
媒体の顕熱を熱電素子によって電気エネルギーに変換し
て回収することを特徴とする高温ガスの顕熱回収方法。A method for recovering the sensible heat of high-temperature gas, which is characterized in that the sensible heat of the high-temperature gas is converted into the sensible heat of a liquid heat medium, and the sensible heat of the heat medium is converted into electrical energy by a thermoelectric element and then recovered.