JPH0735434A - Absorption type freezer - Google Patents
Absorption type freezerInfo
- Publication number
- JPH0735434A JPH0735434A JP5179111A JP17911193A JPH0735434A JP H0735434 A JPH0735434 A JP H0735434A JP 5179111 A JP5179111 A JP 5179111A JP 17911193 A JP17911193 A JP 17911193A JP H0735434 A JPH0735434 A JP H0735434A
- Authority
- JP
- Japan
- Prior art keywords
- absorption
- concentration
- liquid
- absorbing
- refrigerator
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Sorption Type Refrigeration Machines (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は吸収式冷凍機に係り、さ
らに詳細には、吸収液の濃度を測定する技術及び測定さ
れた吸収液濃度を監視して吸収液の稀釈運転等の濃度管
理を行う技術に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an absorption refrigerating machine, and more particularly to a technique for measuring the concentration of an absorption liquid and monitoring the measured concentration of the absorption liquid to control the concentration such as dilution operation of the absorption liquid. Related to the technology of doing.
【０００２】[0002]
【従来の技術】一般に吸収式冷凍機は、吸収媒体として
臭化リチウム、および冷媒として水が使用される。臭化
リチウムは腐食性が高いので、吸収液中には構成金属材
料の腐食を抑制するために腐食抑制剤が添加されてい
る。2. Description of the Related Art Generally, an absorption refrigerator uses lithium bromide as an absorption medium and water as a refrigerant. Since lithium bromide is highly corrosive, a corrosion inhibitor is added to the absorbing liquid to suppress the corrosion of the constituent metal materials.
【０００３】しかし、吸収液中に腐食抑制剤が含まれて
いても、吸収式冷凍機の腐食によるトラブルを完全に回
避することができない。これは、運転停止時の吸収液の
稀釈が不十分なことに起因する吸収液の結晶化が大きな
要因とされる。However, even if the absorption liquid contains a corrosion inhibitor, it is not possible to completely avoid troubles due to corrosion of the absorption refrigerator. This is largely due to the crystallization of the absorption liquid due to the insufficient dilution of the absorption liquid when the operation was stopped.
【０００４】すなわち、吸収液の稀釈が不十分である
と、運転停止時の温度低下に伴い腐食抑制剤を含まない
吸収媒体（例えば臭化リチウム）の結晶と腐食抑制剤を
含んだ稀薄吸収液（例えば温度が低下したときの飽和臭
化リチウム水溶液）の２つに吸収液が分離し、冷凍機の
再運転時に結晶化した臭化リチウムが解け溶融塩に近い
濃厚な臭化リチウム水溶液になり、これと腐食抑制剤を
含んだ稀薄吸収液との比重の差が大きいため、分離した
２つの液が均一になるには時間がかかる。その結果、溶
融塩に近い濃厚臭化リチウム水溶液は腐食抑制剤が含ま
れていない状態となり、金属材料の腐食促進および防食
の役目をしていた酸化皮膜を局部的に破壊する原因とな
る。That is, if the absorption liquid is not sufficiently diluted, the diluted absorption liquid containing the corrosion inhibitor-free crystals of the absorption medium (for example, lithium bromide) that does not contain the corrosion inhibitor along with the temperature decrease when the operation is stopped. (For example, saturated lithium bromide aqueous solution when the temperature drops) The absorbing liquid is separated into two, and when the refrigerator is restarted, the crystallized lithium bromide is dissolved and becomes a concentrated aqueous lithium bromide solution close to the molten salt. However, since there is a large difference in specific gravity between this and the diluted absorbent containing the corrosion inhibitor, it takes time for the two separated liquids to become uniform. As a result, the concentrated lithium bromide aqueous solution, which is close to the molten salt, is in a state of not containing a corrosion inhibitor, which causes local destruction of the oxide film that serves to promote corrosion and prevent corrosion of the metal material.
【０００５】上記問題に対処するため、吸収式冷凍機の
運転停止時に稀釈のための運転が行われるが、従来は稀
釈運転をタイマ等を用いて一定時間行うか、特開平２−
２１３６５９号のように高温再生器の温度に対応して稀
釈運転時間を設定したり、特開昭６３−２４３６６３号
のように冷媒供給配管に取り付けたフロート式流量制御
弁により高温再生器の圧力から制御弁の開閉を行って稀
釈運転をしたり、特開昭６０−２８５８号、特開昭６０
−１６２１６２号、特開昭６１−１０１７６５号、特開
昭６１−７０３５０号、特開昭６３−１８７０７５号、
特開平１−１２３９６０号、特開平２−４０４５９号等
に開示されるように、吸収液の濃度を吸収液の何らかの
状態（例えば、比重，温度，圧力等）から算出して、所
定濃度となるように稀釈運転を制御する技術が提案され
ている。In order to deal with the above problem, an operation for dilution is performed when the absorption refrigerating machine is stopped. Conventionally, the dilution operation is performed for a fixed time by using a timer or the like.
No. 213659, the dilution operation time is set according to the temperature of the high temperature regenerator, or the pressure of the high temperature regenerator is adjusted by the float type flow control valve attached to the refrigerant supply pipe as in JP-A-63-243663. The control valve is opened / closed to perform a dilution operation, or disclosed in JP-A-60-2858 and JP-A-60.
-162162, JP-A-61-101765, JP-A-61-70350, JP-A-63-187075,
As disclosed in JP-A-1-123960, JP-A-2-40459, etc., the concentration of the absorbing liquid is calculated from some state of the absorbing liquid (eg, specific gravity, temperature, pressure, etc.) to obtain a predetermined concentration. As described above, a technique for controlling the dilution operation has been proposed.
【０００６】そのほか、稀釈運転以外でも、例えば特開
昭５９−１２２８７１号に記載の吸収冷凍機における発
生器の熱源熱量制御、特開昭６０−７８２６２号の熱源
供給停止時刻制御、特開昭６１−１７８７２号の吸収液
の結晶化予防技術、特開昭６３−２９７９７０号の吸収
式冷凍機の運転監視技術等に吸収液の濃度を吸収液の何
らかの状態から求める技術が開示されている。In addition to the dilution operation, for example, heat source heat quantity control of a generator in an absorption chiller described in JP-A-59-122871, heat source supply stop time control in JP-A-60-78262, and JP-A-61. No. 17872 discloses a technique for preventing crystallization of an absorbing solution, and JP-A No. 63-297970 discloses a technique for monitoring the operation of an absorption chiller, which discloses a technique for determining the concentration of the absorbing solution from some state of the absorbing solution.
【０００７】[0007]
【発明が解決しようとする課題】上記従来技術のうち、
吸収液の稀釈運転等の濃度管理を行うには、吸収液の濃
度を測定して行うのが最も信頼性があり好ましい。特に
吸収液の濃度を直接検出することが理想とされるが、実
際にはどのようにして直接濃度を検出するか具体的な手
法が開発されておらず、その代わりとして吸収液の物理
状態（例えば、特開昭６０−２８５８号では吸収液の温
度測定及び比重測定、特開昭６０−１６２１６２号では
吸収液の比重測定、特開昭６１−１７８７２号では吸収
液の温度と圧力及び冷媒の温度、特開昭６１−１０１７
６５号では冷凍機の負荷，発生器の加熱量，冷媒量等、
特開昭６１−７０３５０号，特開平１−１２３９６０号
では吸収液の飽和蒸気圧と温度、特開平２−４０４５９
号では凝縮器の熱媒体温度と移送管の再生器出口，熱回
収器の吸収液の温度等）から濃度換算を行う間接的な濃
度測定法が提案されていた。Of the above-mentioned conventional techniques,
In order to control the concentration such as dilution operation of the absorbing solution, it is most reliable and preferable to measure the concentration of the absorbing solution. In particular, it is ideal to directly detect the concentration of the absorption liquid, but in practice, no specific method has been developed to directly detect the concentration, and instead, the physical state of the absorption liquid ( For example, in JP-A-60-2858, the temperature and specific gravity of the absorbent are measured, in JP-A-60-162162, the specific gravity of the absorbent is measured, and in JP-A-61-17872, the temperature and pressure of the absorbent and the refrigerant are measured. Temperature, JP-A-61-1017
In No. 65, refrigerator load, generator heating amount, refrigerant amount, etc.
In JP-A-61-70350 and JP-A-1-123960, the saturated vapor pressure and temperature of the absorbing liquid are described in JP-A-2-40459.
In this issue, an indirect concentration measurement method was proposed in which the concentration was converted from the heat medium temperature of the condenser, the regenerator outlet of the transfer pipe, the temperature of the absorbing liquid of the heat recovery unit, etc.).
【０００８】本発明の目的は、この種の吸収式冷凍機の
吸収液の濃度を従来以上に直接的に実測することで、そ
の濃度モニタの精度ひいては濃度管理の信頼性を高める
ことにある。An object of the present invention is to directly measure the concentration of the absorption liquid of this type of absorption refrigerator and to improve the accuracy of the concentration monitor and thus the reliability of concentration control.
【０００９】[0009]
（１）本発明は上記目的を達成するため、基本的な課題
解決手段として、吸収式冷凍機において、前記吸収液の
循環経路の一部に吸収液に含まれる成分と酸化還元反応
を生じる部材を作用電極として参照電極と共に配置し、
該作用電極と参照電極との電位差から前記吸収液の酸化
還元電位を測定する手段と、前記吸収液の温度を測定す
る手段と、前記酸化還元電位の測定値を温度補正して吸
収液濃度に変換する手段とを備えたものを提案する。(1) In order to achieve the above object, the present invention is, as a basic means for solving the problem, a member in an absorption refrigerating machine that causes a redox reaction with a component contained in the absorption liquid in a part of the circulation path of the absorption liquid. Is arranged with the reference electrode as a working electrode,
Means for measuring the redox potential of the absorbing solution from the potential difference between the working electrode and the reference electrode, means for measuring the temperature of the absorbing solution, and temperature-correcting the measured value of the redox potential to obtain the absorbing solution concentration. And a means for converting are proposed.
【００１０】例えば、吸収式冷凍機の吸収液として、Ｌ
ｉＢｒが用いられ、吸収液に含まれる腐食抑制剤とし
て、Ｋ，Ｎａ，Ｌｉ等のアルカリ金属からなるモリブデ
ン酸塩、クロム酸塩、バナジン酸塩、タングステン酸
塩、塩化ルテニウム、Ｃｏ，Ｓｂ，Ｙ，Ｔｉ等の塩化
物、臭化物、ヨウ化物等のうち少なくとも一つが含まれ
る。For example, as the absorption liquid of the absorption refrigerator, L
iBr is used, and as a corrosion inhibitor contained in the absorbing solution, molybdate, chromate, vanadate, tungstate, ruthenium chloride, Co, Sb, Y made of an alkali metal such as K, Na or Li is used. , Ti, etc., and at least one of chloride, bromide, iodide, etc. is contained.
【００１１】作用電極としては、その吸収液中で酸化還
元反応を起こすＭｏ，Ｃｒ，Ｖ，Ｗ，Ｒｕ，Ｃｏ，Ｓ
ｂ，Ｙ，Ｔｉ等の金属または、酸化モリブデン等の酸化
物、またはＰｔ，Ｃ，Ａｕ等の不溶性電極が使用され
る。As the working electrode, Mo, Cr, V, W, Ru, Co and S which cause an oxidation-reduction reaction in the absorbing liquid are used.
A metal such as b, Y or Ti, an oxide such as molybdenum oxide, or an insoluble electrode such as Pt, C or Au is used.
【００１２】また、腐食抑制剤にＫ，Ｎａ，Ｌｉ等のア
ルカリ金属からなる炭酸塩、硝酸塩、亜硝酸塩のいずれ
かを用いたときには、Ｐｔ，Ｃ，Ａｕ等の不溶性電極が
作用電極として用いられる。When any one of carbonates, nitrates and nitrites made of alkali metals such as K, Na and Li is used as the corrosion inhibitor, an insoluble electrode such as Pt, C and Au is used as a working electrode. .
【００１３】参照電極としては、例えば銀／塩化銀電
極、銀／臭化銀電極、カロメル電極等を用いる。As the reference electrode, for example, a silver / silver chloride electrode, a silver / silver bromide electrode, a calomel electrode or the like is used.
【００１４】（２）さらに、応用手段として、上記
（１）の構成要素に加えて、前記酸化還元電位より求め
た吸収液濃度が設定濃度になるように冷凍機運転停止時
における冷凍機内の吸収液の稀釈運転を制御する手段を
備えたものを提案する。(2) Further, as an application means, in addition to the constituent elements of (1) above, absorption in the refrigerator when the refrigerator is stopped so that the absorption liquid concentration obtained from the redox potential becomes a set concentration. It is proposed to provide a means for controlling the liquid dilution operation.
【００１５】[0015]
（１）の課題解決手段の作用…本発明では、吸収液の成
分と酸化還元反応を生じる作用電極の酸化還元電位を該
作用電極と参照電極との電位差から測定する。また、酸
化還元電位は吸収液の温度に影響されるので、測定した
電位差（酸化還元電位）を温度補正する。例えば、腐食
抑制剤としてモリブデン酸塩が含まれる吸収液におい
て、Ｍｏを作用電極として使用する場合に生じる酸化還
元反応は次の化１に示される。Function of the means for solving the problem of (1) ... In the present invention, the redox potential of the working electrode that causes a redox reaction with the components of the absorbing liquid is measured from the potential difference between the working electrode and the reference electrode. Further, since the oxidation-reduction potential is affected by the temperature of the absorbing solution, the measured potential difference (oxidation-reduction potential) is temperature-corrected. For example, a redox reaction that occurs when Mo is used as a working electrode in an absorbing liquid containing molybdate as a corrosion inhibitor is shown in the following chemical formula 1.
【００１６】[0016]
【化１】 [Chemical 1]
【００１７】この反応の酸化還元電位は、数１式に示さ
れるネルンストの式に従い、吸収液に含まれるモリブデ
ン酸イオンの濃度とその時の吸収液の温度により決定さ
れる。The redox potential of this reaction is determined by the concentration of molybdate ion contained in the absorbing solution and the temperature of the absorbing solution at that time according to the Nernst equation shown in the equation (1).
【００１８】[0018]
【数１】 Ｅ＝Ｅ0＋ＲＴ／（６Ｆ）＊ｌｎ［ＭｏＯ4 2~］ Ｅ：酸化還元電位 Ｅ0：標準電極電位 Ｒ：気体定数 Ｔ：温度 Ｆ：ファラデー定数 ［ＭｏＯ4 2~］：モリブデン酸イオン濃度 吸収液は吸収式冷凍機内で濃縮、稀釈を繰り返すが、常
に吸収液すなわち（例えば臭化リチウム）の濃度と腐食
抑制剤（例えばモリブデン酸塩）の濃度の比率が等しい
ため、腐食抑制剤の濃度から吸収液の濃度を決定するこ
とができる。[Equation 1] E = E 0 + RT / (6F) * ln [MoO 4 2 ~] E: Redox potential E 0 : Standard electrode potential R: Gas constant T: Temperature F: Faraday constant [MoO 4 2 ~]: Molybdate ion concentration The absorption liquid is repeatedly concentrated and diluted in an absorption refrigerator, but since the ratio of the concentration of the absorption liquid (ie, lithium bromide) and the concentration of corrosion inhibitor (eg, molybdate) are always the same, corrosion The concentration of the absorption liquid can be determined from the concentration of the inhibitor.
【００１９】なお、上記の例では、作用電極が吸収液中
の腐食抑制剤と酸化還元反応を起こす例を示したが、吸
収媒体，作用電極の部材を選定することで、吸収媒体と
酸化還元反応を起こすように作用電極を構成することも
可能である。In the above example, the working electrode causes an oxidation-reduction reaction with the corrosion inhibitor in the absorbing liquid. However, by selecting the absorbing medium and the member of the working electrode, the absorbing medium and the oxidation-reduction reaction can be reduced. It is also possible to configure the working electrode to cause a reaction.
【００２０】（２）の課題解決手段の作用…作用電極，
参照電極を用いて、冷凍機内の吸収液濃度を電位差（酸
化還元電位）として測定する。通常の運転で測定される
電位差を図３に示すＥ２とする。冷凍機の運転停止後、
冷凍機内の温度が低下しても吸収液が結晶化しない濃度
の時の電位差をＥ１とすると、Ｅ２からＥ１に電位差が
変化するまで稀釈運転を続けることで吸収液の結晶化が
防止できる。Operation of means for solving the problem of (2) ... Working electrode,
Using the reference electrode, the concentration of the absorbing liquid in the refrigerator is measured as a potential difference (oxidation-reduction potential). The potential difference measured in normal operation is E2 shown in FIG. After stopping the operation of the refrigerator,
Letting E1 be the potential difference at a concentration at which the absorption liquid does not crystallize even if the temperature inside the refrigerator decreases, crystallization of the absorption liquid can be prevented by continuing the dilution operation until the potential difference changes from E2 to E1.
【００２１】なお、この電極部（作用電極，参照電極）
を吸収式冷凍機内の１箇所に限定せず、吸収液が循環す
る高温再生器の底部、低温再生器から熱交換器へ向かう
出口、熱交換器から吸収器に向かう出口、吸収器から熱
交換器に向かう出口等の複数箇所に設置することによ
り、吸収液をさらに精度良く稀釈することができるよう
になり、１箇所の電位測定では分からないような結晶化
が生じやすい場所の稀釈も行うことができる。This electrode portion (working electrode, reference electrode)
Is not limited to one location in the absorption refrigerator, the bottom of the high temperature regenerator in which the absorbing liquid circulates, the outlet from the low temperature regenerator to the heat exchanger, the outlet from the heat exchanger to the absorber, heat exchange from the absorber By installing it at multiple points such as the outlet toward the vessel, it is possible to dilute the absorbing liquid with higher accuracy, and also to dilute the point where crystallization is likely to occur, which cannot be understood by measuring the potential at one point. You can
【００２２】[0022]
【実施例】本発明の一実施例を図面を用いて説明する。
図１は冷媒に水、腐食抑制剤としてモリブデン酸塩を使
用した二重効用吸収式冷凍機の一例である。An embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows an example of a double-effect absorption refrigerator using water as a refrigerant and molybdate as a corrosion inhibitor.
【００２３】図１において、ＬｉＢｒ，ＬｉＯＨ，Ｌｉ
2ＭｏＯ4水溶液からなる吸収液６は高温再生器１ａで濃
縮加熱されて、水蒸気１４を分離する。水蒸気１４は配
管イを介して低温再生器１ｂの熱交換器を通って稀薄吸
収液６ｂを加熱濃縮して凝縮器２に入り、ここで冷却水
１５により冷却されて水となる。この水が冷媒７とな
り、冷媒７は配管ロ，ハを介して冷媒ポンプ８ｂにより
蒸発器３に圧送され、蒸発管１０に散布される（符号１
１は散布された冷媒である）。散布された冷媒１１は、
蒸発器３内が数ｍｍＨｇの減圧状態に保持されているた
め蒸発して再び水蒸気となる。この時の蒸発潜熱により
蒸発管１０の内部を通る冷水９は冷却され、これが冷房
に用いられる。In FIG. 1, LiBr, LiOH, Li
The absorbing liquid 6 made of 2 MoO 4 aqueous solution is concentrated and heated in the high temperature regenerator 1a to separate the water vapor 14. The steam 14 passes through the heat exchanger of the low temperature regenerator 1b via the pipe a to heat and concentrate the diluted absorption liquid 6b and then enters the condenser 2, where it is cooled by the cooling water 15 to become water. This water becomes the refrigerant 7, and the refrigerant 7 is pressure-fed to the evaporator 3 by the refrigerant pump 8b via the pipes B and C and is sprayed on the evaporation pipe 10 (reference numeral 1).
1 is the sprayed refrigerant). The sprayed refrigerant 11 is
Since the inside of the evaporator 3 is kept in a reduced pressure state of several mmHg, it is evaporated to become steam again. The cold water 9 passing through the inside of the evaporation pipe 10 is cooled by the latent heat of evaporation at this time, and this is used for cooling.
【００２４】蒸発した冷媒１１の水蒸気は吸収器４に入
り、ここで高温再生器１ａで濃縮された濃厚吸収液６ａ
が散布されて、この中に吸収される。濃厚吸収液６ａは
水蒸気を吸収する際に発熱するが、これは冷却管１３内
を通る冷却水１２により冷却され、稀薄吸収液６ｂとな
る。稀薄液６ｂは溶液ポンプ８ａにより、熱交換器５を
通って配管ニを介して高温再生器１ａに、及び配管ホを
介して低温再生器１ｂに送り戻される。The evaporated water vapor of the refrigerant 11 enters the absorber 4, where the concentrated absorbent 6a concentrated in the high temperature regenerator 1a.
Are scattered and absorbed into this. The rich absorbing liquid 6a generates heat when absorbing the water vapor, but this is cooled by the cooling water 12 passing through the inside of the cooling pipe 13 to become the dilute absorbing liquid 6b. The diluted liquid 6b is sent back by the solution pump 8a through the heat exchanger 5 to the high temperature regenerator 1a via the piping d and to the low temperature regenerator 1b via the piping e.
【００２５】以上が通常の運転時の冷凍サイクルである
が、本実施例では、吸収式冷凍機の運転停止時おける吸
収液を稀釈するための運転が、吸収液濃度をモニタしな
がら設定稀釈濃度となるように行われる。ここで、稀釈
運転の機構について説明する（濃度モニタ及びその制御
系については後述する）。Although the refrigeration cycle during normal operation has been described above, in this embodiment, the operation for diluting the absorbing liquid when the absorption refrigerating machine is stopped is the set diluting concentration while monitoring the absorbing liquid concentration. Is done. Here, the mechanism of the dilution operation will be described (the concentration monitor and its control system will be described later).
【００２６】高温再生器１ａでの吸収液の濃縮加熱が停
止される。冷媒配管ハから分岐した冷媒供給配管１８に
配置したバルブ１７を開き、冷媒ポンプ８ｂにより冷媒
７を高温再生器１ａに送る。溶液ポンプ８ａは吸収器４
の稀薄吸収液６ｂを高温再生器１ａおよび低温再生器１
ｂに送り、高温再生器１ａと低温再生器１ｂから送られ
る濃厚吸収液６ａは吸収器４に送られる。吸収液６は高
温再生器１ａ、低温再生器１ｂ、熱交換器５、および吸
収器４を吸収液ポンプ８ａにより循環しながら稀釈され
る。Concentration and heating of the absorption liquid in the high temperature regenerator 1a is stopped. The valve 17 arranged in the refrigerant supply pipe 18 branched from the refrigerant pipe C is opened, and the refrigerant 7 is sent to the high temperature regenerator 1a by the refrigerant pump 8b. Solution pump 8a is absorber 4
The diluted absorbent 6b of the high temperature regenerator 1a and the low temperature regenerator 1
The concentrated absorbent 6a sent to the high temperature regenerator 1a and the low temperature regenerator 1b is sent to the absorber 4. The absorption liquid 6 is diluted while circulating through the high temperature regenerator 1a, the low temperature regenerator 1b, the heat exchanger 5, and the absorber 4 by the absorption liquid pump 8a.
【００２７】稀釈運転が完了した時点で吸収式冷凍機は
完全に停止し、冷凍機内は放冷により温度が低下する。
この時、吸収液の稀釈が不十分な状態、すなわち稀釈終
了後の吸収液の濃度が冷凍機内の放冷後の温度で飽和濃
度を超えている時、冷凍機の運転を停止すると、冷凍機
内の温度が低下して吸収液６が結晶化する。特に濃厚溶
液が循環する高温再生器１ａ、低温再生器１ｂ、熱交換
器５で吸収液の結晶化が生じ易い。When the dilution operation is completed, the absorption refrigerator is completely stopped, and the temperature inside the refrigerator is lowered by cooling.
At this time, when the dilution of the absorption liquid is insufficient, that is, when the concentration of the absorption liquid after the dilution is over the saturation concentration at the temperature after cooling in the refrigerator, if the operation of the refrigerator is stopped, The temperature of 1 decreases and the absorbing liquid 6 crystallizes. Especially in the high temperature regenerator 1a, the low temperature regenerator 1b, and the heat exchanger 5 in which the concentrated solution circulates, the absorption liquid is likely to be crystallized.
【００２８】吸収液が結晶化するとＬｉＢｒの結晶とＬ
ｉＯＨ，Ｌｉ2ＭｏＯ4が含まれる飽和ＬｉＢｒ水溶液と
の２つに分離する。この状態で冷凍機が再運転すると冷
凍機内の吸収液の循環および温度上昇によりＬｉＢｒ結
晶は溶解するが溶融塩に近い濃厚状態の水溶液となる。
一方、ＬｉＯＨ，Ｌｉ2ＭｏＯ4が含まれる飽和ＬｉＢｒ
水溶液は、濃厚なＬｉＯＨ，Ｌｉ2ＭｏＯ4を含まないＬ
ｉＢｒ水溶液と濃度および比重が大きく異なるため、吸
収液の均一化には多くの時間が必要となる。吸収液が均
一になる間、吸収式冷凍機の構成材料はＬｉＯＨ，Ｌｉ
2ＭｏＯ4を含まない濃厚ＬｉＢｒ水溶液にさらされ、構
成材料上の酸化皮膜を局部的に破壊し腐食が生じる恐れ
がある。When the absorbing solution is crystallized, LiBr crystals and L
Separated into two , iOH and a saturated LiBr aqueous solution containing Li 2 MoO 4 . When the refrigerator is restarted in this state, the LiBr crystal dissolves due to the circulation of the absorption liquid in the refrigerator and the temperature rise, but becomes a concentrated aqueous solution close to the molten salt.
On the other hand, saturated LiBr containing LiOH and Li 2 MoO 4
The aqueous solution contains L that does not contain concentrated LiOH and Li 2 MoO 4.
Since the concentration and the specific gravity are significantly different from the iBr aqueous solution, it takes a lot of time to make the absorbing solution uniform. While the absorption liquid is uniform, the constituent materials of the absorption refrigerator are LiOH, Li
2 When exposed to a concentrated LiBr aqueous solution that does not contain 2 MoO 4 , the oxide film on the constituent materials may be locally destroyed and corrosion may occur.
【００２９】この結晶化を確実に防止するために、稀釈
運転時の吸収液の濃度を測定するモニタ手段が必要であ
る。図２に本実施例の吸収液６すなわちＬｉＢｒの濃度
を測定する濃度モニタ装置を示す。In order to reliably prevent this crystallization, a monitor means for measuring the concentration of the absorbing solution during the dilution operation is necessary. FIG. 2 shows a concentration monitor device for measuring the concentration of the absorbing liquid 6 of the present embodiment, that is, LiBr.
【００３０】この濃度モニタ装置は、作用電極１９、参
照電極２０および熱電対（温度測定手段）２１から構成
された電極部２２と、電位差計（酸化還元電位算出手
段）２３、変換装置（酸化還元電位−濃度変換手段）２
４から構成される。作用電極１９は吸収液中の成分（こ
こでは、腐食抑制剤としてのモリブデン酸塩）と酸化還
元反応を示す部材（本例ではＭｏ）を使用し、参照電極
２０に高温水用銀／塩化銀参照電極を使用する。This concentration monitor comprises an electrode section 22 composed of a working electrode 19, a reference electrode 20 and a thermocouple (temperature measuring means) 21, a potentiometer (oxidation / reduction potential calculation means) 23, a converter (oxidation / reduction). Potential-concentration conversion means) 2
It is composed of 4. The working electrode 19 uses a component in the absorbing liquid (here, molybdate as a corrosion inhibitor) and a member (Mo in this example) that exhibits an oxidation-reduction reaction, and the reference electrode 20 is silver for high temperature water / silver chloride. Use a reference electrode.
【００３１】この電極部２２を吸収式冷凍機内の吸収液
が循環する高温再生器１ａの底部に吸収液中に挿入され
るようにして取り付ける。なお、電極部２２は吸収液６
が循環する箇所、例えば、低温再生器１ｂから熱交換器
５へ向かう出口、熱交換器５から吸収器４に向かう出
口、吸収器４から熱交換器５に向かう出口等に設置して
も良い。さらに、上述した箇所に１か所の設置ばかりで
はなく２箇所以上の場所に設置することにより複数個所
の濃度測定も行える。The electrode portion 22 is attached to the bottom of the high temperature regenerator 1a in which the absorbing liquid in the absorption refrigerator circulates so as to be inserted into the absorbing liquid. In addition, the electrode part 22 has
May be installed at a place where the heat is circulated, for example, an outlet from the low temperature regenerator 1b to the heat exchanger 5, an outlet from the heat exchanger 5 to the absorber 4, an outlet from the absorber 4 to the heat exchanger 5, and the like. . Further, not only one place is installed at the above-mentioned place, but also the concentration can be measured at a plurality of places by installing at two or more places.
【００３２】上記構成の濃度モニタ装置によれば、Ｍｏ
（作用電極１９）上で起こる腐食抑制剤の酸化還元電位
が、電位差計２３により作用電極１９と参照電極２０と
の電位差を測定することにより求められる。すなわち、
腐食抑制剤であるＬｉ2ＭｏＯ4は水溶液中ではＭｏＯ4 2
~の状態で存在する。ＭｏＯ4 2~は化１に示される酸化還
元反応を作用電極１９上で生じており、その反応によっ
て作用電極１９上で生じている酸化還元電位が参照電極
２０との電位差として電位差計２３により測定される。
化１に示される酸化還元反応は既述の数１式のネルンス
トの式に基づきＭｏＯ4 2~の濃度と吸収液６の温度に比
例し変化する。そのため、熱電対２１により測定された
高温再生器１ａ内の吸収液６の温度からＭｏＯ4 2~から
得られる酸化還元電位は変換装置２４を用いて温度補正
が行われる。According to the concentration monitor having the above structure, the Mo
The redox potential of the corrosion inhibitor that occurs on (working electrode 19) is determined by measuring the potential difference between working electrode 19 and reference electrode 20 with a potentiometer 23. That is,
Li 2 MoO 4 which is a corrosion inhibitor is MoO 4 2 in an aqueous solution.
Exists in the state of. MoO 4 2 ~ causes the redox reaction shown in Chemical formula 1 to occur on the working electrode 19, and the redox potential generated on the working electrode 19 by the reaction is measured by the potentiometer 23 as a potential difference from the reference electrode 20. To be done.
The redox reaction shown in Chemical formula 1 changes in proportion to the concentration of MoO 4 2 and the temperature of the absorbing liquid 6 based on the Nernst equation of the above-mentioned Numerical formula 1. Therefore, the temperature of the redox potential obtained from MoO 4 2 is corrected using the converter 24 from the temperature of the absorbing liquid 6 in the high temperature regenerator 1a measured by the thermocouple 21.
【００３３】温度補正後の測定値はＭｏＯ4 2~の濃度よ
って変化する。そこで、吸収液中のＬｉＢｒ濃度とＬｉ
2ＭｏＯ4の濃度はつねに一定の比率で存在しているか
ら、図３に示すように測定された電位差からモリブデン
酸塩の濃度が決定でき、その値を用いてＬｉＢｒの濃度
も決定できる。The measured value after temperature correction changes depending on the concentration of MoO 4 2 ~. Therefore, the LiBr concentration and Li in the absorption liquid
Since the concentration of 2 MoO 4 is always present in a constant ratio, the concentration of molybdate can be determined from the measured potential difference as shown in FIG. 3, and the concentration can also be used to determine the concentration of LiBr.
【００３４】ＭｏＯ4 2~を含んだ吸収液で使用する作用
電極１９としては、ＭｏのほかにＰｔ，Ａｕ，Ｃのよう
な不溶性電極、ＭｏＯ2等を用いることができる。ま
た、参照電極２０としてＡｇ／ＡｇＣｌ電極以外にもＨ
ｇ／Ｈｇ2Ｃｌ2電極やＡｇ／ＡｇＢｒ電極等を使用でき
る。As the working electrode 19 used in the absorbing solution containing MoO 4 2 ~, in addition to Mo, an insoluble electrode such as Pt, Au, C, MoO 2 or the like can be used. In addition to the Ag / AgCl electrode, H is used as the reference electrode 20.
A g / Hg 2 Cl 2 electrode, an Ag / AgBr electrode, or the like can be used.
【００３５】次に上記の濃度モニタを用いた、吸収式冷
凍機の運転停止時における稀釈運転の制御について説明
する。Next, the control of the dilution operation using the above concentration monitor when the absorption refrigerating machine is stopped will be described.
【００３６】稀釈運転の制御装置２５は、吸収式冷凍機
の停止信号を受け取ると、高温再生器１ａに取り付けら
れている熱源、例えばガスバーナや石油ボイラ等を停止
する。熱源の停止後、冷媒供給配管１８に取り付けられ
たバルブ１７を開け、冷媒７を強制的に高温再生器１ａ
に戻す。溶液ポンプ８ａ、冷媒ポンプ８ｂは制御装置２
５が冷凍機の停止信号を受け取った後も引き続き作動
し、吸収液６の稀釈が行こなわれる。When the control device 25 for the dilution operation receives the stop signal for the absorption refrigerator, it stops the heat source such as the gas burner and the oil boiler attached to the high temperature regenerator 1a. After stopping the heat source, the valve 17 attached to the refrigerant supply pipe 18 is opened to force the refrigerant 7 into the high temperature regenerator 1a.
Return to. The solution pump 8a and the refrigerant pump 8b are the control device 2
5 continues to operate even after receiving the refrigerator stop signal, and the absorption liquid 6 is diluted.
【００３７】稀釈操作の終了の判断は電極部２２から電
位差計２３、変換装置２４を経て温度補正された作用電
極１９と参照電極２０の電位差により行われる。通常の
運転時の吸収液濃度のときの電位差は図３に示されるＥ
２の電位差である。稀釈操作により稀釈された吸収液の
電位差は大きくなり、冷凍機の停止後吸収液の温度が室
温になったときにでも結晶化しない５５％ＬｉＢｒ濃度
のときの電位差Ｅ１に近づく。変換装置から送られる電
位差がＥ１に達すると制御装置２５から電気信号が送ら
れ、溶液ポンプ８ａ、冷媒ポンプ８ｂが作動停止し、冷
媒供給配管１８に取り付けられたバルブ１７が閉めら
れ、稀釈運転が終了する。The determination of the end of the dilution operation is made by the potential difference between the working electrode 19 and the reference electrode 20 whose temperature is corrected through the potentiometer 23, the converter 24 from the electrode section 22. The potential difference at the concentration of the absorbing solution during normal operation is shown by E in FIG.
The potential difference is 2. The potential difference of the absorption liquid diluted by the dilution operation becomes large, and approaches the potential difference E1 at the 55% LiBr concentration that does not crystallize even when the temperature of the absorption liquid reaches room temperature after the refrigerator is stopped. When the potential difference sent from the converter reaches E1, an electric signal is sent from the controller 25, the solution pump 8a and the refrigerant pump 8b are deactivated, the valve 17 attached to the refrigerant supply pipe 18 is closed, and the dilution operation is performed. finish.
【００３８】本実施例によれば、吸収液の稀釈運転を行
う場合に、吸収液の濃度を濃度に応じて酸化還元電位が
決定される電極を用いて測定し、かつ温度補正が伴うの
でより直接的な濃度測定を可能にし、測定精度を高め、
ひいては稀釈運転性の信頼性を高めることができ、その
結果、冷凍機運転停止後の吸収液の結晶化をより正確に
防止することにより、冷凍機の腐食の原因を排除でき
る。According to the present embodiment, when the absorption liquid is diluted, the concentration of the absorption liquid is measured using an electrode whose redox potential is determined according to the concentration, and the temperature correction is involved. Enables direct concentration measurement, improves measurement accuracy,
As a result, the reliability of the diluting operability can be improved, and as a result, the cause of corrosion of the refrigerator can be eliminated by more accurately preventing the crystallization of the absorbing liquid after the refrigerator is stopped.
【００３９】また、濃度モニタ、すなわち、電極部２２
を吸収式冷凍機内の循環経路に２箇所以上設置すること
により、１箇所で電位差を測定するよりもさらに確実な
稀釈運転を行い得る。すなわち、電極部を複数配置した
場合、一方で電位差がＥ１に達しても、もう一方がＥ１
に達しなければの制御装置は２５は稀釈操作が不十分と
判断、運転を継続し、溶液ポンプ８ａ、冷媒ポンプ８ｂ
の作動停止は両者がＥ１に達した後となる。Further, the concentration monitor, that is, the electrode unit 22
By installing two or more in the circulation path in the absorption refrigerator, more reliable dilution operation can be performed than measuring the potential difference at one location. That is, in the case where a plurality of electrode portions are arranged, even if the potential difference reaches E1 on one side, the potential difference on the other side becomes E1.
If it does not reach 25, the control device 25 judges that the dilution operation is insufficient and continues the operation, and the solution pump 8a and the refrigerant pump 8b
The operation will stop after both reach E1.
【００４０】なお、上記実施例は濃度モニタ装置を冷凍
機運転停止後の稀釈運転に利用するが、その他、冷凍機
の運転中の吸収液の異常を判別するための監視等種々の
管理に利用することができる。In the above embodiment, the concentration monitor is used for the dilution operation after the refrigerator is stopped, but in addition, it is used for various management such as monitoring for determining the abnormality of the absorbent during the operation of the refrigerator. can do.
【００４１】[0041]
【発明の効果】本発明によれば、吸収液に含まれる成分
と酸化還元反応を生じる作用電極を用いて吸収液の濃度
を測定することで、この種の吸収式冷凍機の吸収液の濃
度を従来以上に直接的に実測することができ、その濃度
モニタの精度ひいては濃度管理の信頼性を高めることが
できる。According to the present invention, the concentration of the absorption liquid of this type of absorption refrigerator is measured by measuring the concentration of the absorption liquid using a working electrode that causes a redox reaction with the components contained in the absorption liquid. Can be measured more directly than before, and the accuracy of the concentration monitor and thus the reliability of concentration control can be improved.
【図１】本発明の一実施例を示す吸収液の濃度モニタを
備えた吸収式冷凍機の構成図。FIG. 1 is a configuration diagram of an absorption refrigerating machine having a concentration monitor of an absorbing liquid according to an embodiment of the present invention.
【図２】上記実施例に用いる濃度モニタの構成図。FIG. 2 is a block diagram of a density monitor used in the above embodiment.
【図３】上記実施例に用いる吸収液のモリブデン酸イオ
ンの酸化還元電位の濃度依存性を示したグラフ。FIG. 3 is a graph showing the concentration dependence of the oxidation-reduction potential of molybdate ions of the absorbent used in the above examples.
１ａ…高温再生器、１ｂ…低温再生器、２…凝縮器、３
…蒸発器、４…吸収器、５…熱交換器、６ａ…濃厚吸収
液、６ｂ…稀薄吸収液、８ａ…溶液ポンプ、８ｂ…冷媒
ポンプ、１７…バルブ、１８…冷媒供給配管、１９…作
用電極、２０…参照電極、２１…熱電対、２３…電位差
計、２４…変換装置（酸化還元電位−濃度変換手段）、
２５…制御装置（稀釈運転制御手段）、イ〜二…吸収液
配管。1a ... high temperature regenerator, 1b ... low temperature regenerator, 2 ... condenser, 3
... Evaporator, 4 ... Absorber, 5 ... Heat exchanger, 6a ... Concentrated absorption liquid, 6b ... Dilute absorption liquid, 8a ... Solution pump, 8b ... Refrigerant pump, 17 ... Valve, 18 ... Refrigerant supply pipe, 19 ... Action Electrode, 20 ... Reference electrode, 21 ... Thermocouple, 23 ... Potentiometer, 24 ... Conversion device (oxidation / reduction potential-concentration conversion means),
25 ... Control device (dilution operation control means), a-2 ... Absorption liquid piping.
Claims (6)
熱交換器、冷媒ポンプ、溶液ポンプ、およびこれらを作
動的に接続する配管系と吸収液を有する吸収式冷凍機に
おいて、前記吸収液の循環経路の一部に吸収液に含まれ
る成分と酸化還元反応を生じる部材を作用電極として参
照電極と共に配置し、該作用電極と参照電極との電位差
から前記吸収液の酸化還元電位を測定する手段と、前記
吸収液の温度を測定する手段と、前記酸化還元電位の測
定値を温度補正して吸収液濃度に変換する手段とを備え
て成ることを特徴とする吸収式冷凍機。1. An evaporator, an absorber, a condenser, a regenerator, a solution heat exchanger, a refrigerant pump, a solution pump, and an absorption refrigerating machine having a piping system operatively connecting these and an absorbing liquid, wherein: A member that causes a redox reaction with a component contained in the absorbing liquid is disposed in a part of the circulation path of the absorbing liquid together with a reference electrode as a working electrode, and the redox potential of the absorbing liquid is determined from the potential difference between the working electrode and the reference electrode. An absorption refrigerating machine comprising: a means for measuring, a means for measuring the temperature of the absorbing solution, and a means for correcting the measured value of the oxidation-reduction potential to convert it into the concentration of the absorbing solution.
り求めた吸収液濃度が設定濃度になるように冷凍機運転
停止時における冷凍機内の吸収液の稀釈運転を制御する
手段を備えて成ることを特徴とする吸収式冷凍機。2. The means according to claim 1, further comprising means for controlling a dilution operation of the absorption liquid in the refrigerator when the operation of the refrigerator is stopped so that the concentration of the absorption liquid obtained from the redox potential becomes a set concentration. Absorption refrigerator.
転制御手段は、前記酸化還元電位より求めた吸収液濃度
に対応して冷媒ポンプと溶液ポンプを運転し、且つ吸収
液を稀釈するために設けた冷媒供給配管のバルブを開閉
制御して、吸収液が所定の濃度に達した時点で前記各ポ
ンプを停止させる制御系により構成したことを特徴とす
る吸収式冷凍機。3. The absorption liquid dilution operation control means according to claim 2, for operating the refrigerant pump and the solution pump in accordance with the absorption liquid concentration obtained from the redox potential and for diluting the absorption liquid. An absorption chiller comprising a control system for controlling the opening and closing of a valve of a refrigerant supply pipe provided in the above, and stopping each of the pumps when the absorption liquid reaches a predetermined concentration.
において、前記吸収液の温度を測定する手段は熱電対に
より構成したことを特徴とする吸収式冷凍機。4. The absorption refrigerator according to claim 1, wherein the means for measuring the temperature of the absorbing liquid is a thermocouple.
において、前記作用電極は、前記吸収液の吸収媒体或い
は腐食抑制剤と酸化還元反応を起こすように設定してあ
ることを特徴とする吸収式冷凍機。5. The working electrode according to any one of claims 1 to 4, wherein the working electrode is set to cause an oxidation-reduction reaction with an absorption medium of the absorbing liquid or a corrosion inhibitor. Absorption refrigerator.
において、前記作用電極及び参照電極を前記吸収液のう
ち濃厚吸収液が循環する経路の複数箇所に配置して、こ
れらの複数箇所の吸収液濃度を測定するように設定した
ことを特徴とする吸収式冷凍機。6. The working electrode and the reference electrode according to any one of claims 1 to 5, wherein the working electrode and the reference electrode are arranged at a plurality of positions in a path in which a concentrated absorbing liquid of the absorbing liquid circulates. An absorption refrigerator, which is set so as to measure the concentration of the absorption liquid of.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5179111A JPH0735434A (en) | 1993-07-20 | 1993-07-20 | Absorption type freezer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5179111A JPH0735434A (en) | 1993-07-20 | 1993-07-20 | Absorption type freezer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0735434A true JPH0735434A (en) | 1995-02-07 |
Family
ID=16060211
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5179111A Pending JPH0735434A (en) | 1993-07-20 | 1993-07-20 | Absorption type freezer |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0735434A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1183229A (en) * | 1997-09-09 | 1999-03-26 | Mitsubishi Heavy Ind Ltd | Device for stopping operation of absorption refrigerating machine |
| JP2011006720A (en) * | 2009-06-23 | 2011-01-13 | Sharp Corp | Treatment apparatus and treating method |
-
1993
- 1993-07-20 JP JP5179111A patent/JPH0735434A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1183229A (en) * | 1997-09-09 | 1999-03-26 | Mitsubishi Heavy Ind Ltd | Device for stopping operation of absorption refrigerating machine |
| JP2011006720A (en) * | 2009-06-23 | 2011-01-13 | Sharp Corp | Treatment apparatus and treating method |
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