Patent Publication Number: US-2015083385-A1

Title: Gas heater / cooler apparatuses and methods

Description:
BACKGROUND OF THE INVENTION 
     Embodiments of the subject matter disclosed herein generally relate to apparatuses and methods used in changing the temperature of fluid flowing through a pipe and, more particularly, to apparatuses and methods in which either heating and/or cooling may be performed with the same equipment. 
     The fossil fuels remain a main source of energy and, therefore, the interest in developing new production fields has increased parallel with the increase of demand. Since the availability of land-based production fields is limited, tapping the vast amounts of offshore reserves has become more imperative in spite of the technical challenges. Due to the limited space on a rig, the offshore oil and gas exploration and exploitation needs more compact equipment than the conventional land-based oil and gas equipment. 
     In conventional gas cooling equipment  1  as illustrated in  FIG. 1 , a container  10  houses a plurality of pipes  20  through which a cooling agent circulates. The cooling agent may be water. A fluid flow of oil or gas whose temperature is sought to be lowered is input through an inlet  30 , and output through an outlet  40 . In its passage from the inlet  30  to the outlet  40 , the fluid flow surrounds the pipes  20 . The cooling agent may be input into the container  10  through a coolant inlet  50  in an inlet plenum  60 , and then split to flow through the pipes  20  by a tube sheet  70 . Similarly, after circulating through the pipes  20 , the cooling agent may pass through an output tube sheet into an output plenum  80 , to be output via a coolant outlet  90 . The output tube sheet is formed as a single piece with the tube sheet  70 . 
     In the gas cooling equipment  1 , the input plenum  60  and the output plenum  80  are located on the same side of the container  10 , the pipes  20  having a U-shape to extend along the container  10 . The pipes  20  may be supported inside the container by baffles  95 . The cooling agent is typically brought back to an initial temperature and re-circulated. 
     The pipes  20  being surrounded by the flow of gas or oil leads to degradation of the pipe walls making possible leaks there-through that would yield contamination of both the flow of gas or oil and the cooling agent. 
     In processing extracted fossil fuel, cooling or heating the flow of gas or oil may become necessary. Conventionally, the heating equipment is separate from the cooling equipment. The presence of two separate equipments has the disadvantage of an increased cost and of an increased space requirement, which space may be scarce (e.g., on a rig operating offshore). 
     Additionally, the conventional use of two separate equipments limits the possibility to promptly adjust the temperature of the gas or oil flow. 
     Accordingly, it would be desirable to provide apparatuses and methods usable to either heat or cool a flow of gas or oil, thus, avoiding the afore-described problems and drawbacks. 
     BRIEF SUMMARY OF THE INVENTION 
     According to one exemplary embodiment, a gas heater/cooler apparatus includes a heat transfer block, a gas pipe, a coolant pipe and an electric heater. The gas pipe is configured to transport a fluid through an inside of the heat transfer block. The coolant pipe is configured to transport coolant agent through the inside of the heat transfer block, the coolant pipe being located in the proximity of the gas pipe to cool the fluid flowing therein via heat exchange with the cooling agent flowing through the coolant pipe. The electric heater is located inside the heat transfer block close to the gas pipe to heat the fluid flowing therein via radiated heat. 
     According to another exemplary embodiment, gas heater/cooler apparatus includes a heat transfer block, a gas pipe, a fan and an electric heater. The gas pipe is configured to transport a fluid through an inside of the heat transfer block. The fan is configured to push a flow of air towards the gas pipe. The electric heater is located inside the heat transfer block close to the gas pipe to heat the fluid flowing therein via radiated heat. 
     According to yet another exemplary embodiment, a method of manufacturing a gas heater/cooler apparatus is provided. The method includes mounting a gas pipe inside a heat transfer block configured to allow a coolant flow to pass there-through cooling a fluid flowing inside the gas pipe. The method further includes mounting an electric heater inside the heat transfer block and in the proximity of the gas pipe. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate one or more embodiments and, together with the description, explain these embodiments. In the drawings: 
         FIG. 1  is a schematic diagram of a conventional gas cooling equipment; 
         FIG. 2  is a schematic diagram of a heater/cooler apparatus according to an embodiment; 
         FIG. 3  is a flow diagram of a method of manufacturing a heater/cooler apparatus according to an embodiment; 
         FIG. 4  is a schematic diagram of a heater/cooler apparatus according to another embodiment; 
         FIG. 5  is a schematic diagram of a heater/cooler apparatus according to another embodiment; 
         FIG. 6  is a schematic diagram of a heater/cooler apparatus according to another embodiment; and 
         FIG. 7  is a schematic diagram of a heater/cooler apparatus according to another embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS OF THE INVENTION 
     The following description of the exemplary embodiments refers to the accompanying drawings. The same reference numbers in different drawings identify the same or similar elements. The following detailed description does not limit the invention. Instead, the scope of the invention is defined by the appended claims. The following embodiments are discussed, for simplicity, with regard to the terminology and structure of a gas processing system. However, the embodiments to be discussed next are not limited to these systems, but may be applied to other systems that require a reduced size equipment capable to both heat or cool a fossil fuel (fluid) flow. 
     Reference throughout the specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the subject matter disclosed. Thus, the appearance of the phrases “in one embodiment” or “in an embodiment” in various places throughout the specification is not necessarily referring to the same embodiment. Further, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments. 
     As discussed above with regard to  FIG. 1 , the prior art equipment has the disadvantage of being bulky because separate pieces of equipment are used for heating and for cooling, respectively. Additionally, exposure of the pipes carrying the cooling agent to the fluid flow leads in time to degradation of the pipes which may result in cross-contaminating leaks. 
     According to one embodiment illustrated in  FIG. 2 , a gas heater/cooler apparatus  100  includes a heat transfer block  110  inside which there is a pipe  120  carrying gas (or other fossil fuel, or fluid) whose temperature is sought to be controlled. The pipe  120  has a shape designed to increase exposure of a longer portion of the pipe  120  to temperature changing agents. For example, the pipe  120  may have a spiral shape (but its shape is not limited thereof). The pipe  120  is made, in an embodiment, from a material that is a good heat conductor, to spend a small amount of energy and time in modifying the temperature of the pipe  120  material. For example, the pipe  120  may be made of stainless steel. 
     A cooling agent is a fluid flow entering the heat transfer block  110  via an inlet  130  and exiting the heat transfer block via an outlet  140 . The heating agent is an electric heater  150  located in the proximity of the pipe  120 . Thus, the gas in the pipe  120  may be cooled by the fluid flow and/or may be heated due to heat radiated by the electric heater  150 , while passing through the heat transfer block  110 . 
     In another embodiment illustrated in  FIG. 3 , a method  200  of manufacturing a gas heater/cooler apparatus includes mounting a gas pipe inside a heat transfer block configured to allow a coolant flow to pass there-through, at S 210 . Further, the method  200  includes mounting an electric heater inside the heat transfer block and in the proximity of the gas pipe, at S 220 . 
     The method  200  may also include mounting temperature sensors at different locations along the gas pipe, and/or along the path of the coolant flow. Temperature sensors may be located before and after an area where heat exchange between gas in the gas pipe  120  and the fluid flow occurs, to measure a change of the temperature of the gas and a change of the temperature of the coolant. 
     The method  200  may further include mounting a fluid regulator on the path of the coolant flow, the fluid regulator being configured to modify the amount of coolant flow entering the heat transfer block. The fluid regulator may be connected to one or more temperature sensors configured to measure a temperature of the coolant and/or of the gas exiting the heat transfer block, to enable the fluid regulator to adjust the amount of coolant flow based on the temperature information received from the one or more sensors. 
     The method  200  may also include mounting a power supply configured to provide power to the electric heater and a switch configured to cut off the power supply based on temperature information received from one or more temperature sensors. 
     In another embodiment, the method  200  may include mounting the flow regulator, the power supply, the switch, and the one or more temperature sensors, and, then, connecting these components to a controller. The controller is configured to control the flow regulator and the power supply to adjust the amount of coolant and the power supplied to the electric heater based on the temperatures measured by the sensors, in order to achieve a target output temperature of the gas in the gas pipe. 
     The method  200  may also include mounting alarms in the apparatus. For example, a cooling agent temperature alarm may be connected to a coolant output temperature sensor located and configured to measure an output temperature of the coolant flow. The cooling agent temperature alarm may be configured to output an alarm signal when the output temperature has a value outside a predetermined temperature range. In another example, a switch may be connected to a coolant output temperature sensor located and configured to measure an output temperature of the fluid flowing inside the gas pipe. The switch may be interposed between the power supply and the electric heater, and be configured to cut off the power to the heater when the output temperature exceeds a predetermined value. 
     According to another exemplary embodiment, illustrated in  FIG. 4 , a gas heater/cooler apparatus  300  includes a heat transfer block  310  inside which a pipe  320  carrying gas whose temperature is sought to be controlled is immerged. The heat transfer block may be made of a casted piece of aluminum. The pipe  320  enters the heat transfer block  310  via an inlet  322  and exits the heat transfer block  310  via an outlet  324 . Close to the inlet  322 , inside or outside the heat transfer block  310 , a first temperature sensor  326  may be located to measure the input temperature of the gas in the pipe  320 . Close to the outlet  324 , inside or outside the heat transfer block  310 , a second temperature sensor  328  may be located to measure the output temperature of the gas in the pipe  320 . For example, the input temperature of the gas in the pipe  320  may be about 250° C., and the output temperature of the gas may be about 150° C. 
     Another pipe  330 , through which a cooling agent flows, is placed inside the heat transfer block  310  in the proximity of the pipe  320 . The pipe  320  and the pipe  330  may have spiral shapes running substantially parallel to each other to maximize the heat exchange therebetween. The cooling agent may be mineral oil. The pipe  330  enters the heat transfer block  310  via an inlet  332  and exits the heat transfer block  310  via an outlet  334 . Close to the inlet  332 , a third temperature sensor  336  may be located inside or outside the heat transfer block  310 , to measure the input temperature of the cooling agent in the pipe  330 . Close to the outlet  334 , a fourth temperature sensor  338  may be located inside or outside the heat transfer block  310 , to measure the output temperature of the cooling agent in the pipe  330 . For example, the input temperature of the cooling in the pipe  330  may be about 70° C., and the output temperature of the cooling agent may be about 75° C. 
     The heat transfer block may be made of a casted piece of aluminum or another material or environment. 
     A gas temperature alarm  329  and/or a cooling agent temperature alarm  339  may be associated with a respective temperature sensor located close to the outlets. The alarms are configured to output alarm signals when the output temperature of the gas or of the cooling agent respectively has a value outside a corresponding predetermined temperature interval or exceeds a corresponding upper or lower value. The alarm signal may be a visual or an audio indication or may trigger adjustment of the coolant flow and/or of the power supplied to the electric heater  340 . 
     The pipes  320  and  330  are made, in an embodiment, from materials (or the same material) that are good heat conductors, to spend a small amount of energy and time in modifying the temperature of the pipes  320  and  330 . For example, the pipes  320  and  330  may be made of stainless steel. 
     An electric heater  340  is located also in the proximity of the pipe  320 , according to an embodiment, in a manner in which to optimize a heat transfer towards the pipe  320  while minimizing a heat transfer towards the pipe  330 . Thus, inside the heat transfer block  310  the gas, the gas in the pipe  320  may be cooled due to the cooling agent in the pipe  330  having a lower temperature than the gas and/or may be heated due to heat radiated by the electric heater  340 . 
     The gas heater/cooler apparatus  300  further includes a power supply  350  that provides power to the electric heater  340  and a flow regulator  360  located along a pipe through which the cooling agent enters the heat transfer block  310 . The flow regulator  360  is configured to control the amount of cooling agent flowing along the pipe  330  inside the heat transfer block  310 . The flow regulator may be an orifice in the coolant pipe wall, an area of the orifice being adjustable. For example, the cooling agent (mineral oil) flow may be about 28 l/min. 
     The temperature sensors  326 ,  328 ,  336 , and  338 , the power supply  350  and the flow regulator  360  may be connected to a controller  370 . The controller  370  may send signals to the power supply  350  and to the flow regulator  360  based on the temperature values received from the temperature sensors  326 ,  328 ,  336 , and  338  in order to achieve a targeted temperature of the gas exiting the heat transfer block  310 . 
     Another schematic diagram of a gas heater/cooler apparatus  380  is illustrated in  FIG. 5 . In addition to elements already described relative to  FIG. 4 , the gas heater/cooler apparatus  380  includes a switch  382  interposed between the power supply  350  and the electric heater  340 , the switch  382  being configured to cut off the power to the electric heater. For example, the power may be cut-off (1) when the output temperature of the gas or the coolant exceeds a predetermined value, (2) when a signal is received from an automatic controller or (3) when the switch is flipped between an open state and a close state by a command received via an interface  384 . The mineral oil flow may be 28 l/min, the mineral oil temperature raising across the heater/cooler apparatus  380  from 70° C. to 75° C., and the gas flow may be 56 l/min the gas temperature dropping across the heater/cooler apparatus  380  from 250° C. to 150° C. 
     A layout of a heater/cooler apparatus  390  similar to the apparatuses  300  and  380  described above is illustrated in  FIG. 6 . The heater/cooler apparatus  390  stands on a mounting foot  392 . The electric heater  340  may be lowered inside or raised outside the heat transfer block  310  using a lifting mechanism  394 . The apparatus operation information (including temperature information) may be transmitted via a module  396 . The heat transfer block  310  may be surrounded by a thermal insulating layer or casing  398 . In  FIG. 6 , the gas pipe  320  and the coolant pipe  330  have helix shapes arranged on the same axis and running substantially parallel to each other. 
     According to another exemplary embodiment, illustrated in  FIG. 7 , a gas heater/cooler apparatus  400  includes a heat transfer block  410  inside which there is a pipe  420  carrying gas whose temperature is sought to be controlled. The pipe  420  enters the heat transfer block  410  via an inlet  422  and exits the heat transfer block  410  via an outlet  424 . The pipe  420  is made, in an embodiment, from a material that is a good heat conductor, to spend a small amount of energy and time in modifying the temperature of the pipe  420 . For example, the pipe  420  may be made of stainless steel. The pipe  420  may have spiral shape to maximize the heat exchange. 
     Close to the inlet  422 , inside or outside the heat transfer block  410 , a first temperature sensor  426  may be located to measure the input temperature of the gas in the pipe  420 . Close to the outlet  424 , inside or outside the heat transfer block  410 , a second temperature sensor  428  may be located to measure the output temperature of the gas in the pipe  420 . 
     A fan  430  pushes an air flow through the heat transfer block  410  towards the pipe  420 . Here, air is mentioned as cooling agent. However, other gas mixtures may be used, cooled and re-circulated through the heat transfer block  410 . The advantage of using air, even ambient air, with temperature between −40° C. to 50° C., is that, in this case, no re-circulating loop is necessary. The air flow pushed by the fan  430  towards the pipe  420  may pass through permeable walls (e.g., walls with holes to allow the air to pass there-through) or may be channeled through openings in the walls. 
     An electric heater  440  is located also in the proximity of the pipe  420 . Thus, inside the heat transfer block  410  the gas, the gas in the pipe  420  may be cooled due to the air flow having a lower temperature than the gas and/or may be heated due to heat radiated by the electric heater  440 . 
     The gas heater/cooler apparatus  400  further includes a first power supply  450  that provides power to the electric heater  440  and a second power supply  460  that provides power to the fan  430 . 
     The temperature sensors  426 ,  428 , and the power supplies  450  and  460  may be connected to a controller  470 . The controller  470  may send signals to the power supplies  450  and  460  based on the temperature information received from the temperature sensors  426 , and  428  in order to achieve a targeted temperature of the gas exiting the heat transfer block  410 . 
     The disclosed exemplary embodiments provide apparatuses and methods of manufacturing thereof in which apparatuses either heating and/or cooling of a fossil fuel (fluid) flow may be performed. It should be understood that this description is not intended to limit the invention. On the contrary, the exemplary embodiments are intended to cover alternatives, modifications and equivalents, which are included in the spirit and scope of the invention as defined by the appended claims. Further, in the detailed description of the exemplary embodiments, numerous specific details are set forth in order to provide a comprehensive understanding of the claimed invention. However, one skilled in the art would understand that various embodiments may be practiced without such specific details. 
     Although the features and elements of the present exemplary embodiments are described in the embodiments in particular combinations, each feature or element can be used alone without the other features and elements of the embodiments or in various combinations with or without other features and elements disclosed herein. 
     This written description uses examples of the subject matter disclosed to enable any person skilled in the art to practice the same, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the subject matter is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims.