JP2012031863A - Fire extinguishing system for an organic rankine cycle hydrocarbon evaporator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic Rankine cycle energy recovery system including features which provide for fire suppression and/or ignition suppression in the event of an unintentional release of a flammable component of the system, for example a flammable working fluid such as cyclopentane, into a part of the of the system in which the prevailing temperature is higher than the autoignition temperature of the flammable component.SOLUTION: The organic Rankine cycle energy recovery system 10 includes an inert gas source 34 disposed upstream of a hydrocarbon evaporator and configured to purge the contents of the hydrocarbon evaporator with an inert gas on detection of a leak thereby.

Description

  The present invention relates generally to organic Rankine cycle energy recovery systems, and more specifically to an evaporator and a method of recovering energy using the evaporator.

  The so-called “waste heat” generated by many human activities is a resource that is valuable but often not fully utilized. Waste heat sources include various types of thermal combustion exhaust gas, including flue gas. Industrial turbomachines such as turbines often produce a large amount of recoverable waste heat in the form of a hot exhaust stream.

  Organic Rankine cycle energy recovery systems are deployed as retrofits, for example, to obtain waste heat from a turbine hot gas stream and convert the recovered heat to the desired power output. In the organic Rankine cycle, heat is transferred to an organic fluid, commonly called a working fluid, in a closed loop. Due to the thermal contact with this waste heat, the working fluid is heated and evaporated, and then expands in a work extraction device such as a turbine, during this expansion, from the expanding working fluid gas to the moving components of the turbine. Expansion kinetic energy is transmitted. This creates mechanical energy that can be converted into, for example, electrical energy. The working fluid gas, which has transferred a portion of its energy content to the turbine, is then condensed into a liquid state and returned to the closed loop heating stage for reuse.

  The working fluid used in such an organic Rankine cycle energy recovery system is generally a low boiling point hydrocarbon such as cyclopentane. Therefore, this working fluid is susceptible to decomposition at high temperatures. In various applications, the organic Rankine cycle energy recovery system makes a heat contact between a heat source gas having an initial temperature of about 500 degrees Celsius and a working fluid across a heat transfer barrier such as a wall of a heat exchange pipe containing the working fluid. Depends on that.

  Therefore, using an organic Rankine cycle energy recovery system to recover waste heat from, for example, a thermal exhaust gas stream generated by a gas turbine has the dilemma that the temperature of the exhaust gas stream is higher than the spontaneous ignition temperature of the working fluid. is there. Under such conditions, direct contact between the working fluid and the exhaust stream resulting from failure of the components of the organic Rankine cycle energy recovery system may increase the risk of fire and / or explosion.

US Pat. No. 7,503,176

  Accordingly, there is a need to provide an improved organic Rankine cycle system that anticipates such system failures and provides suitable means to reduce the risk.

  In one aspect, the present invention provides: (a) a housing, a heat source gas inlet, a heat source gas outlet, a working fluid inlet, a working fluid outlet, and a working fluid inlet and a working fluid outlet in fluid communication with the housing. An evaporator comprising a heat exchanger tube disposed; (b) a detector having the ability to sense a working fluid or combustion by-products of the working fluid; (c) a work extraction device; (d) a condenser; a controller comprising: e) a pump; (f) an inert gas source disposed upstream of the evaporator; (g) a controller configured to receive the output of the detector; and (h) a heat source gas bypass. Is configured to operate the inert gas source, the controller is configured to divert the heat source gas to the heat source gas bypass, and the controller is configured to prevent introduction of the working fluid into the evaporator. To provide a down Kin cycle energy recovery system.

  In another aspect, the present invention is a method for recovering energy from an organic Rankine cycle system, comprising: (i) introducing a heat source gas into an evaporator comprising a heat exchange tube containing a working fluid; and (ii) a heat source gas. Transferring heat from the working fluid to produce a heated working fluid; (iii) transferring energy from the heated working fluid to a work extraction device located outside the evaporator; (Iv) returning the working fluid to the evaporator, and in the organic Rankine cycle energy recovery system configured to detect the working fluid or combustion by-products of the working fluid and generate a signal in response to the detection The organic Rankine cycle energy recovery system is configured to receive a signal from the detector at the controller; The controller is configured to activate an inert gas source upstream of the evaporator in response to this signal, and the controller is configured to divert the heat source gas to the heat source gas bypass in response to this signal. The controller is responsive to this signal to provide a method configured to prevent introduction of the working fluid into the evaporator.

  In another aspect, the present invention is an evaporation apparatus for use in an organic Rankine cycle energy recovery system comprising a housing, a heat source gas inlet, a heat source gas outlet, a working fluid inlet, a working fluid outlet, A heat exchange tube disposed in the housing in fluid communication with the fluid inlet and the working fluid outlet, and a detector having the ability to sense the working fluid or combustion by-products of the working fluid; An evaporation device coupled to a valve configured to be switchable between a fluid source and an inert gas source is provided.

  These features, aspects and advantages of the present invention, as well as other features, aspects and advantages will be more fully understood when the following detailed description is read with reference to the accompanying drawings. Like numerals refer to like parts throughout the drawings.

1 is a schematic diagram of an organic Rankine cycle energy recovery system according to an embodiment of the present invention. 1 is a schematic diagram of an organic Rankine cycle energy recovery system according to an embodiment of the present invention. 6 is a flow diagram illustrating the operation of an organic Rankine cycle energy recovery system in response to detection of a working fluid leak according to an embodiment of the present invention.

  In the following specification and in the claims that follow, reference is made to a number of terms that are defined to have the following meanings.

  Unless otherwise apparent by context, the singular forms “a”, “an”, and “the” include plural referents.

  “As appropriate” or “as appropriate” means that the event or situation described below may or may not occur, and that the description may or may not occur. It means to include.

  It is also understood that terms such as “top”, “bottom”, “outside”, “inside” are terms for convenience and should not be construed as limiting terms. Further, certain features of the invention comprise at least one of a group of several elements and combinations of those elements, or of a group of several elements and combinations of those elements When said to consist of at least one, the feature comprises any of those elements of the group, individually or in combination with any of the remaining elements of the group, Alternatively, it is understood that any of those elements of the group can be made individually or in combination with any of the remaining elements of the group.

  Throughout this specification and the claims, approximate terms are used to modify a quantitative expression that can be changed without hindrance without causing a change in the underlying function to which the expression relates. May be. Thus, a value modified by one or more terms such as “about” is not limited to the specified value. In some cases, an approximation word may correspond to the accuracy of the instrument that measures the value. Similarly, the term “free” may be used in combination with a term, which may contain an insubstantial number or trace amount, but the modified term is still It is considered not to exist.

  As described above, in one embodiment, the present invention is in fluid communication with (a) a housing, a heat source gas inlet, a heat source gas outlet, a working fluid inlet, a working fluid outlet, a working fluid inlet and a working fluid outlet. An evaporator comprising a heat exchange tube disposed in the housing in a state; (b) a detector having the ability to sense a working fluid or combustion by-products of the working fluid; (c) a work extraction device; (d) A condenser; (e) a pump; (f) an inert gas source located upstream of the evaporator; (g) a controller configured to receive the output of the detector; and (h) a heat source gas bypass. And the controller is configured to operate the inert gas source, the controller is configured to divert the heat source gas to the heat source gas bypass, and the controller prevents the introduction of the working fluid to the evaporator. An organic Rankine cycle energy recovery system configured.

  FIG. 1 is a schematic diagram of an organic Rankine cycle energy recovery system 10 according to one embodiment of the present invention. The system includes an evaporator 12 coupled to a heat source (not shown) that supplies a heat source gas 17 (see FIG. 2). In various embodiments of the present invention, this heat source can be any heat source that can be used to generate a gas stream that can be introduced into the evaporator through a heat source gas inlet. For example, a gas turbine can be used as a heat source, and exhaust gas from the gas turbine can be used as a heat source gas. Other heat sources include exhaust gas generating equipment used in residential, commercial and industrial environments, such as clothes dryers, air conditioning units, refrigeration units, gas streams generated during fuel combustion, such as flue gas.

  Referring again to FIG. 1, the evaporator 12 includes a housing 14, a heat source gas inlet 16, a heat source gas outlet 18, a working fluid inlet 22 and a working fluid outlet 24. The housing defines a heat source gas flow path from the heat source gas inlet to the heat source gas outlet. In one embodiment, this heat source gas flow path is essentially the entire interior of the evaporator defined by the walls of the housing and the interior space of the evaporator not occupied by the heat exchange tubes 20. The heat exchange tube 20 is disposed in the housing in fluid communication with the working fluid inlet and the working fluid outlet. In one embodiment, the heat exchange tube 20 is disposed in the heat source gas flow path. In other embodiments, the heat exchange tube 20 is not disposed in the heat source gas flow path.

  In the embodiment shown in FIGS. 1 and 2, the heat exchange tube 20 is shown as a single tube disposed between a single working fluid inlet 22 and a single working fluid outlet 24. However, as used herein, the expression “a heat exchange tube disposed in the housing in fluid communication with the working fluid inlet and the working fluid outlet” refers to one or more working fluid inlets and one or more working fluid inlets. And may include a plurality of heat exchange tubes disposed in the evaporator housing in fluid communication with the working fluid outlet.

  The heat exchange tube 20 is configured to contain an organic Rankine cycle working fluid 40 (see FIG. 2). As described above, in the embodiment shown in FIG. 1, the evaporator 12 is coupled to a heat source (not shown) configured to supply the heat source gas 17 (see FIG. 2), and the working fluid 40 is supplied to the working fluid 40. In order to facilitate heat exchange between the working fluid 40 and the heat source gas without overheating, the heat source gas 17 enters the evaporator 12 through the heat source gas inlet 16 and follows the heat source gas flow path 70 (see FIG. 2). Contact the heat exchange tube 20. In one embodiment, the working fluid 40 moves along a working fluid flow path (not shown) defined by the interior of the heat exchange tube 20. In one embodiment, the temperature of the heat source gas is from about 375 degrees Celsius to about 450 degrees Celsius.

  As described above, in one embodiment, the working fluid 40 is a hydrocarbon. Non-limiting examples of hydrocarbons include cyclopentane, n-pentane, isopentane, propane, butane, n-hexane and cyclohexane. In other embodiments, the working fluid 40 can be a mixture of two or more hydrocarbons. In one embodiment, the working fluid 40 is a binary fluid such as, for example, cyclohexane-propane, cyclohexane-butane, cyclopentane-isopentane, cyclopentane-butane, a cyclopentane-cyclohexane mixture. In other embodiments, the working fluid 40 is a hydrocarbon selected from the group consisting of cyclopentane, cyclohexane, and mixtures thereof. In other embodiments, the working fluid 40 is a hydrocarbon selected from the group consisting of cyclopentane and cyclohexane.

  The organic Rankine cycle energy recovery system provided by the present invention comprises a detector 26, which is a working fluid or one or several combustion by-products of the working fluid present at one or more locations in the system. Has the ability to detect even small amounts. For the purposes of this disclosure, the light emitted by the combustion of the working fluid is considered a combustion byproduct, and in various embodiments of the invention, the detector detects such light in the evaporator. Composed. Thus, in one embodiment, this detector is placed in the evaporator 12. In an alternative embodiment, the detector is in a portion of the organic Rankine cycle energy recovery system downstream of the evaporator 12, such as in a pipe downstream of the heat source gas outlet configured to remove the heat source gas from the evaporator. Placed in. One skilled in the art can devise other suitable locations where the detector 26 can be placed based on various sensors and organic Rankine cycle system designs.

  In one embodiment, the detector 26 is a photodetector, a metal oxide sensor, a solid state sensor, an infrared spectroscopic detector, an ultraviolet-visible spectroscopic detector, a thermocouple or other temperature sensor, an optical pyrometer, an optical fiber sensor, Selected from the group consisting of a resistive thermal device for measuring gas temperature and a flame detector. In one embodiment, the detector 26 is a photodetector having the ability to sense light emitted during combustion of the working fluid. In an alternative embodiment, the detector comprises an infrared spectroscopic detector.

  The organic Rankine cycle energy recovery system of the present invention includes an inert gas source 34 upstream of the evaporator. When used in reference to an inert gas source, the expression “upstream of the evaporator” means that when the inert gas is allowed to enter the evaporator device, the inert gas is introduced into the working fluid inlet, eg, the working fluid inlet 22. Means that the inert gas source is configured to pass through the evaporator. In general, both the inert gas source 34 and the working fluid return line shown as element 72 in FIG. 2 are coupled to a multi-way valve 46 linked to the controller 36. When the multi-way valve is open with respect to the inflow of fluid from the inert gas source 34 to the inside of the heat exchange tube 20, the multi-way valve 46 with respect to the inflow of the working fluid 40 (FIG. 2) into the inside of the heat exchange tube 20. The state of the multi-way valve 46 is controlled so that is closed. In one embodiment, the multi-way valve 46 is a two-way valve. Thus, the organic Rankine cycle energy recovery system provided by the present invention is configured such that the inflow of the working fluid to the evaporator and the inflow of the fluid from the inert gas source are mutually exclusive. With this mutual exclusion principle and the controller controlling the state of the multi-way valve 46, in various embodiments, the controller is said to be configured to prevent introduction of working fluid into the evaporator.

  The inert gas source can include any flame suppression and / or ignition suppression fluid, and the inert gas source need not be included in the strict definition of the term “inert gas”. The role of the inert gas source is to expel the working fluid in the evaporator when a failure leading to leakage of the working fluid occurs in the system. For example, when leakage of the working fluid is caused by the presence of a pinhole in the heat exchange pipe 20 in the evaporator, a detector located in the evaporator or downstream of the evaporator is used as the working fluid or the working fluid. And detecting a combustion by-product, generating a signal that is received by the controller. In particular, the controller instructs the multi-way valve 46 to close with respect to the flow of working fluid into the evaporator and open with respect to the flow of flame suppression and / or ignition suppression fluid from the inert gas source. Thus, in one embodiment, it is said that the controller is configured to “activate” the inert gas source, which simply means that the controller does not supply fluid from the inert gas source to the evaporator. It means that the inflow can be started.

  In one embodiment, the inert gas source 34 includes an inert gas selected from the group consisting of nitrogen, argon, carbon dioxide, and combinations thereof. In an alternative embodiment, the inert gas source comprises a flame suppression and / or ignition suppression fluid comprising a halocarbon such as heptafluoropropane (see FM-200®). In one embodiment, the inert gas source consists essentially of nitrogen.

  As described above, the organic Rankine cycle energy recovery system includes a controller 36 configured to receive an output signal from the detector 26, which output signal is a working fluid or actuation by the detector that indicates that the working fluid has leaked. Produced as a result of sensing fluid combustion by-products. The controller includes various system components such as a heat source gas inlet valve 44 that is controlled to direct the heat source gas to the evaporator 12 or the heat source gas bypass 38 upon receiving an output signal from the detector, and herein. The multi-way valve 46, also referred to as a working fluid inlet valve 46, can be operated to control. In one embodiment, during operation of the organic Rankine cycle energy recovery system 10, the detector 26 is located in the evaporator 12 outside the heat exchange tube 20, at least of the working fluid 40 and the combustion by-products of the working fluid 40. A signal is sent to the controller 36 when one senses the presence. The controller can communicate with the detector and various other system components via a wireless or wired communication link, or a combination of wireless and wired communication links. In one embodiment, the communication link is configured to transmit an electrical signal. In an alternative embodiment, the communication link is configured to transmit an optical signal. In other embodiments, the communication link can carry either an electrical signal or an optical signal. In one embodiment, the communication link is configured to transmit an acoustic signal. In one embodiment, controller 36 is coupled to detector 26 via communication link 50, coupled to heat source gas inlet valve 44 via communication link 48, and coupled to working fluid inlet valve 46 via communication link 52. Is done.

  As described above, the controller 36 switches the valve 46 and initiates the flow of inert fluid (flame suppression and / or ignition suppression fluid) from the inert gas source 34 through the working fluid inlet 22, thereby causing the evaporator device The inert gas source 34 is configured to be activated by expelling any working fluid present in the heat exchange pipe 20 inside. The expelled working fluid is transferred to some part of the organic Rankine cycle energy recovery system located outside the evaporator, which can safely contain the working fluid until needed, such as a working fluid holding tank (not shown) be able to. Further, the operation of the inert gas source 34 is performed to prevent further working fluid from being introduced into the evaporator through the working fluid inlet.

  As described above, the controller 36 is configured to divert the heat source gas to the heat source gas bypass 38. As a result, when the working fluid leaks in the evaporator, the evaporator can be quickly cooled.

  During operation of the organic Rankine cycle energy recovery system, the heat of the heat source gas is transferred to the working fluid 40 contained within the heat exchange tube 20 to produce a heated working fluid (sometimes also referred to as “working fluid vapor”). To do. The temperature of the heat source gas entering the evaporator may vary depending on the type of heat source and the distance between the heat source and the evaporator. In one embodiment, the temperature of the heat source gas entering the evaporator is from about 350 degrees Celsius to about 600 degrees Celsius. In one embodiment, the temperature of the heated working fluid emerging from the evaporator through the working fluid outlet is from about 150 degrees Celsius to about 300 degrees Celsius. In one embodiment, the pressure of the heated working fluid is about 20 to about 30 bar.

  The heated working fluid vapor can pass through the expander 28 to drive a work extraction device (not shown). In exemplary embodiments, the expander is a radial expander, an axial expander, an impulse expander, or a high temperature screw expander. After passing through the expander 28, the working fluid vapor having a relatively low pressure and low temperature that transferred some of its energy to the expander is passed to the condenser 30 where it is condensed and in a liquid state working fluid 40. And then pumped by pump 32 and returned from working fluid inlet 22 to evaporator 12. In other embodiments, after passing through the expander 28, a working fluid vapor having a relatively low pressure and low temperature can function as a heat exchange unit before entering the condenser (recuperator). (Not shown). In one example, the condensed working fluid can be supplied to the evaporator 12 at a pressure of about 20 bar and a temperature of about 50 degrees Celsius. The evaporator, work extractor, condenser and pump are configured to operate with a working fluid confined in a closed loop.

  Referring to FIG. 2, this figure shows a portion of an organic Rankine cycle energy recovery system 10 according to an exemplary embodiment of the present invention comprising an evaporator 12 and other system components. The evaporator 12 includes a housing 14, a heat source gas inlet 16 and a heat source gas outlet 18. In the illustrated embodiment, the heat exchange tube 20 is disposed in the heat source gas flow path 70 inside the evaporator. As shown in FIG. 2, the heat source gas flow path 70 is essentially the entire interior of the evaporator 12 defined by the wall 78 of the housing and the interior space of the evaporator 12 not occupied by the heat exchange tubes 20. It is. In the embodiment shown in FIG. 2, the heat exchange tube 20 is secured within the evaporator housing 14 by a portion 80 embedded in the housing wall 78 of the heat exchange tube 20. Located downstream of the heat source gas outlet 18 is a detector 26 having the ability to sense the working fluid or combustion products of the working fluid. A heat source gas bypass 38 is coupled to the heat source gas inlet 16 via a heat source gas inlet valve 44. The valve 44 can be switched to direct the heat source gas flow to the evaporator or heat source gas bypass. The working fluid inlet 22 is coupled to a working fluid inlet valve 46, which is also coupled to an inert gas source 34. In the embodiment shown in FIG. 2, the heat source gas inlet valve 44, working fluid inlet valve 46 and detector 26 are coupled to the controller 36 via corresponding communication links 48, 52 and 50, respectively.

  As described above, in one aspect, the present invention provides a method for recovering energy from an organic Rankine cycle system. In one embodiment, the method comprises (i) introducing a heat source gas into an evaporator comprising a heat exchange tube containing a working fluid; and (ii) transferring heat from the heat source gas to the working fluid to produce a heated operation. Generating a fluid; (iii) transferring energy from a heated working fluid to a work extraction device located outside the evaporator; and (iv) returning the working fluid to the evaporator. . The method is implemented in an organic Rankine cycle energy recovery system configured to detect a working fluid or combustion by-products of the working fluid. Further, the organic Rankine cycle energy recovery system is configured to generate a signal in response to detection of the working fluid or combustion by-products of the working fluid. The organic Rankine cycle energy recovery system is configured to receive a signal from the detector at the controller, and the controller is configured to activate an inert gas source upstream of the evaporator in response to the signal. In addition, the controller is configured to divert the heat source gas to the heat source gas bypass and divert it from the evaporator in response to this signal, and in addition to the introduction of additional working fluid to the evaporator in response to this signal. Configured to prevent.

  Referring to FIG. 3, this figure shows a flow diagram 100 illustrating a method according to an embodiment of the present invention for operating an organic Rankine cycle energy recovery system. In a first method step 108, the detector 26 detects the presence of at least one of the working fluid 40 and the combustion by-product of the working fluid 40, generates a signal in response to the detection, and sends the signal to the controller. 36. In a second method step 110, the controller initiates an organic Rankine cycle energy recovery system emergency shutdown protocol that includes steps 112-122. In a first series of method steps 112-118, the controller instructs the pump to stop transporting the working fluid to the evaporator (112) and gradually turns on the expander bypass 54 (see FIG. 1). Instructs to open (114), diverts heat source gas to heat source gas bypass, directs away from evaporator (116), full fan (not shown in FIG. 1) coupled to condenser Set to power and instruct to maximize the heat removal capability of the condenser (118). Method steps 112-118 may be performed in any order depending on the situation. Following method steps 112-118, the controller activates the inert gas source at method step 120 to initiate a purge of working fluid from one or more heat exchange tubes in the evaporator. The purged working fluid can be stored in a suitable safe place. At method step 122, the flow of flame suppression and / or ignition suppression fluid from an inert gas source may be terminated. In an alternative embodiment, inflow of flame suppression and / or ignition suppression fluid from an inert gas source is continued to maintain an inert atmosphere within the various components of the system. For example, in the event of a major failure in one or more heat exchange tubes in the evaporator, by continuing the flow of flame suppression and / or ignition suppression fluid from an inert gas source, An inert atmosphere in the heat source gas flow path and the heat source gas flow path downstream of the evaporator can be maintained.

  This document uses several examples to disclose the invention, including its best mode, and to make and use any device or system and perform any method incorporated Thus enabling one skilled in the art to practice the invention. The patentable scope of the invention is defined by the claims that follow, and may include other examples that occur to those skilled in the art. Such other examples are when they have structural elements that do not differ from the character representation of the claims, or when they contain equivalent structural elements that differ only slightly from the character representation of the claims, It is intended to be included within the scope of the claims.

DESCRIPTION OF SYMBOLS 10 Organic Rankine cycle energy recovery system 12 Evaporator 14 Housing 16 Heat source gas inlet 18 Heat source gas outlet 20 Heat exchange pipe 22 Working fluid inlet 24 Working fluid outlet 26 Detector 28 Expander 30 Condenser 32 Pump 34 Inert gas source 36 Controller 38 Heat source gas bypass 40 Working fluid 42 Work extraction device 44 Heat source gas inlet valve 46 Working fluid inlet valve 48 Communication link between controller and heat source gas inlet valve 50 Communication link between controller and detector 52 Between controller and working fluid inlet valve Communication link 54 Inflator bypass 58 Heat source gas 70 Heat source gas flow path 72 Working fluid return line 78 Housing wall 80 Embedded portion of heat exchange pipe 100 Flow diagram 108 Method step 110 Method step 112 Method step 114 method Step 116 method step 118 method step 120 method step 122 method step

Claims (10)

(A) a housing (14), a heat source gas inlet (16), a heat source gas outlet (18), a working fluid inlet (22), a working fluid outlet (24), the working fluid inlet (22) and the An evaporator (12) comprising a heat exchange tube (20) disposed in the housing (14) in fluid communication with a working fluid outlet (24);
(B) a detector (26) having the ability to sense the working fluid (40) or combustion by-products of the working fluid (40);
(C) a work extraction device (42);
(D) a condenser (30);
(E) a pump (32);
(F) an inert gas source (34) disposed upstream of the evaporator (12);
(G) a controller (36) configured to receive the output of the detector (26);
(H) a heat source gas bypass (38), and
The controller (36) is configured to operate the inert gas source (34);
The controller (36) is configured to divert heat source gas to the heat source gas bypass (38);
An organic Rankine cycle energy recovery system, wherein the controller (36) is configured to prevent introduction of a working fluid (40) into the evaporator (12). The energy recovery system of claim 1, wherein the detector (26) is selected from the group consisting of a gas sensor, a photodetector, a solid state sensor, an infrared spectroscopic detector, an ultraviolet detector, a temperature sensor, and a flame sensor. The energy recovery system of any preceding claim, wherein the detector (26) is disposed within the housing (14) of the evaporator. The energy recovery system of claim 1, wherein the detector (26) is disposed outside the housing (14) of the evaporator. The energy recovery according to claim 1, wherein the inert gas source (34) comprises an inert gas selected from the group consisting of nitrogen, argon, carbon dioxide and combinations of two or more of these gases. system. A method of recovering energy from an organic Rankine cycle system,
(I) introducing a heat source gas (58) into an evaporator (12) comprising a heat exchange tube (20) containing a working fluid (40);
(Ii) transferring heat from the heat source gas (58) to the working fluid (40) to produce a heated working fluid;
(Iii) transferring energy from the heated working fluid to a work extraction device (42) located outside the evaporation device (12);
(Iv) returning the working fluid (40) to the evaporator (12);
Implemented in an organic Rankine cycle energy recovery system configured to detect the working fluid (40) or a combustion byproduct of the working fluid (40) and generate a signal in response to the detection. ,
The organic Rankine cycle energy recovery system is configured to receive the signal from a detector at a controller;
The controller is configured to activate an inert gas source upstream of the evaporator in response to the signal;
The controller is configured to divert the heat source gas to a heat source gas bypass in response to the signal;
The method wherein the controller (36) is configured to prevent introduction of a working fluid (40) into the evaporator (12) in response to the signal. The organic Rankine cycle energy recovery system is
(A) a housing (14), a heat source gas inlet (16), a heat source gas outlet (18), a working fluid inlet (22), a working fluid outlet (24), the working fluid inlet (22) and the An evaporator (12) comprising a heat exchange tube (20) disposed in the housing (14) in fluid communication with a working fluid outlet (24);
(B) a detector (26) having the ability to sense the working fluid or combustion by-products of the working fluid;
(C) a work extraction device (42);
(D) a condenser (30);
(E) a pump (32);
(F) an inert gas source (34) disposed upstream of the evaporator (12);
(G) a controller (36) configured to receive the output of the detector (26);
(H) a heat source gas bypass (38), and
The controller (36) is configured to operate the inert gas source (34);
The controller (36) is configured to divert heat source gas to the heat source gas bypass (38);
The method of claim 6, wherein the controller (36) is configured to prevent introduction of a working fluid (40) into the evaporator (12). The method of claim 6, wherein the working fluid (40) is selected from the group consisting of methylcyclopentane, methylcyclobutane, cyclopentane, isopentane and cyclohexane. The method of claim 6, wherein the heat source gas (58) is flue gas. An evaporator used in an organic Rankine cycle energy recovery system,
A housing (14), a heat source gas inlet (16), a heat source gas outlet (18), a working fluid inlet (22), a working fluid outlet (24), the working fluid inlet (22) and the working fluid outlet A heat exchange tube (20) disposed in the housing (14) in fluid communication with (24) and capable of sensing the working fluid (40) or combustion by-products of the working fluid (40); A working fluid inlet (22) coupled to a valve (46) configured to be switchable between a working fluid source (72) and an inert gas source (34). Evaporation equipment.