Patent Application
20190154343
The present invention relates to heat exchangers. More specifically, to a single heat exchanger with multiple tubes carrying one or more independent fluids exchanging heat with one common fluid.
A heat exchanger is a device that is designed to use heat transfer in order to change the temperature of a first volume of a substance using the temperature of a separate volume of a substance. In order to work, the two volumes of substances are placed within operative communication of each other such that heat can be transferred from one volume of substance to the other. Heat transfer, via either conduction or convection, tends to use the heat from a first substance to warm a cooler second substance. Thus, the warmer substance is cooled and the cooler substance is warmed. However, because the substances are continually moving through the heat exchanger, the heat transfer between the two substances is a continuous process that tends not to reach equilibrium. It should be noted that the substances are not mixed but rather stay isolated from one another.
Fluids are generally used to transfer heat. As used herein, “fluid” can mean either the liquid phase, or the gaseous phase, of a substance. Thus, “fluid” could be used herein to describe either a liquid, such as but not limited to water or oil, or a gas, such as but not limited to air, nitrogen, or oxygen. Further, although it is not intended to be limiting in regard to the types of fluids that might oil and gas industry where fluids are generally hydrocarbons. As used herein, “hydrocarbon” refers to various fluid forms of organic compounds that are comprised of hydrogen and carbon. Common hydrocarbons include, but are not limited to, petroleum based fuels, solvents, and lubricants.
There are various types of heat exchangers, such as gas to liquid cooling, liquid to gas cooling, liquid to liquid cooling, or gas to gas cooling. In each case, heat is transferred from one warmer substance to the other cooler substance, for example transferring heat from a warm gas to a cool liquid.
When designing heat exchangers, manufacturers usually select materials for the apparatus that have good thermal conductivity as a property so that there is relatively easy heat transfer between the substances and thus, a high heat transfer coefficient. The heat transfer coefficient is a quantitative characteristic of convective heat transfer between a fluid medium (a fluid) and the surface (wall) flowed over by the fluid. The heat transfer coefficient depends on both the thermal properties of a medium, the hydrodynamic characteristics of its flow, and the hydrodynamic and thermal boundary conditions. An additional consideration when choosing the material is that it (or they, in the case of multiple materials) be compatible with the substances that will be in contact with the material during the heat transfer. Copper and stainless steel are examples of materials that are often used.
There are various types and forms of apparatuses (heat exchangers) used to put the substances in operative communication with each other such that heat can be exchanged. For example, tube and fin heat exchangers consist of fins, hairpin tubes, return bends to connect the hairpins, a tube sheet to support and properly align the tubes, a header with inlets and outlets, side plates for structural support, and usually a fan plate. The tubes provide the path for the liquid coolant, and the thin ads surface area for more heat convection.
Another example is the flat tube heat exchanger which also has tubes and fins however, the tubes are flat instead of round. The surface area of the flat tubes is also much greater than the surface area of the tubes in a tube and fin heat exchanger. The additional surface area of the tubes in an flat tube heat exchanger maximizes heat transfer when poor heat transfer fluids like oil or ethylene glycol are used. These heat exchangers consist of fin, flat tubes, a welded header with inlets and outlets, and plates, including an optional fan plate.
Conventional shell and tube heat exchangers are one of the most widely used types of heat exchangers and are built in various configurations. A shell and tube exchanger consists of a number of tubes mounted inside a cylindrical shell that may often be found in a petrochemical plant. Two fluids can exchange heat, one fluid flows over the outside of the tubes while the second fluid flows through the tubes. The fluids can be single or two phase, and can flow in the same direction, or in opposite directions.
The basic components of a shell and tube heat exchanger consist of a multiplicity of round tubes incased in a round, hollow cylinder referred to as the shell. A multiplicity of tubes may be referred to as a tube set. The tubes run generally parallel to the shell and are mounted on centralizers called baffles. The baffles serve two purposes, they hold and support the tubes separated and in place, they are also used to divert the shell side product flow in a non-linear path across the tubes for better heat transfer. A tube sheet is a flat plate with holes or apertures through it corresponding with the number of tubes in the exchanger. The tube sheet is mounted at the end of the shell cylinder. The tubes pass through their corresponding holes in the tube sheet and the gap between the tubes and tube sheet is sealed. The tube sheet's function is to separate the liquid running through the shell from the liquid running through the tubes. Coupled about the perimeter of the tube sheet, opposite the shell chamber, may be a channel head. The channel head supplies an inlet or an outlet for the tube side liquid and forms a common header for the liquid to enter the tubes. A end cap or bonnet is coupled to the header (generally, but not necessarily, to the end opposite the tube sheet), or the outside ends of the channel head.
There are heat exchanger designs that allow for two or more different products passing through the tube side of a shell and tube heat exchanger but these designs require partitions on both ends of the exchanger, requiring flanges and gaskets that make the design overly complicated, and making the exchanger very prone to leaking, which in turn requires expensive down time for repairs. This conventional design is also prone to clogging which requires additional down time for cleaning. The alternative to these designs is to add separate heat exchangers for the different product streams. One of the problems with this scenario is by adding additional exchangers there is a necessity that there be a way to connect the multiple exchangers together which also greatly increases the systems cost. The other problem with a multi exchanger system is the space or the foot print needed to make such a system work.
The present invention it is for an apparatus that allows for controlled heat transfer of multiple substances in a pass, or a single substance with multiple passes, through a single heat exchanger shell which may be mounted on a transportable skid. The method of the present invention provides for moving a multiplicity of liquid or gaseous substances through a multiplicity of designated tubes which are located inside a shell containing a heat exchanging substance.
In the oil and gas industry in particular, there has been a need to utilize skid mounted production equipment that can be moved to a production facility, used until no longer needed, then loaded on a truck and transported to another production facility. This means the size and weight of skid mounted equipment, of any kind, that can be loaded on a transport truck is limited. The current method to reduce size and weight is to split the production equipment onto two are more skids which greatly increases the cost and the feasibility of mounting certain production equipment on a portable skid.
The cooling area to weight ratio required for traditional tube and shell heat exchangers is very high when compared to this new invention which reduces size and weight while maintaining the same performance. The way in which this new invention accomplishes this is by running two are more products through one common shell with the use of multiple tube sheets to keep the products separated. This new design considerably reduces overall weight, overall size, and overall cost. When required, heat exchangers can be one of the most essential and costly components in the oil and gas industry, they are very complex, heavy and use a lot of valuable space, this invention simplifies the process making the concept of transportable skid mounted production equipment more feasible.
The traditional design uses a divider plate welded in the channel header with a machined flange that bolts to the tube sheet which requires a gasket. The traditional design is very expensive to produce as opposed to the current invention which uses an extra outside tube sheet to separate the products which can be welded directly to channel header pipe without the need for an internal divider which requires a bolted flange and bolted tube sheet to be able to install the divider.
Fin tube exchangers tend to be less expensive to manufacture, but are less efficient than the more expensive shell and tube design. By using an extra tube sheet to separate two products running through only one shell, this new design is able to eliminate an extra exchanger needed for the two separate products and consequently makes the more efficient shell and tube exchanger less expensive to manufacture.
The heat exchanger herein has a cylindrical shell with a hollow interior that extends from from a first aperture at the first end of the shell to a second aperture at the second end of the shell. The shell also has a shell outlet near said first end of the shell and a shell inlet near the second end of the shell. Inside the shell, running lengthwise from shell end to end is a tube bundle which is made up of a multiplicity of tube sets, with each tube set made up of a multiplicity of tubes.
A second input tube sheet is coupled to the first end of the shell across the first aperture. Tube sheets have a multiplicity of holes the number of which is corresponding with the number of said tubes in the shell. A cylindrical, hollow, second input head creates a second input head chamber, and the first end of the second input head is coupled to the second input tube sheet opposite said shell. The second input head has a second input head inlet.
Basically mirroring the above, a second output tube sheet is coupled to the second end of the shell across the second aperture. The second output tube sheet has a multiplicity of holes the number of which corresponds with the number of the tubes in the tube bundle. A cylindrical and hollow, second output head creates a second output head chamber. The first end of the second output head is coupled to the second output tube sheet opposite the shell. The second output head has a second output head inlet.
Lined up generally linearly is a first input tube sheet coupled to the second end of the second input head. The first input tube sheet has a multiplicity of holes the number of which corresponds with the number of tubes in a first tube set. The first input head is generally hemispherical and hollow creates a first input head chamber. The equatorial end of the first input head is coupled to the first input tube sheet opposite the second input head. The first input head hays a first input head inlet.
Lined up generally linearly is a first output tube sheet coupled to the second end of the second output head. The first output tube sheet has a multiplicity of holes the number of which corresponds with the number of holes in the first input tube sheet. The first output head is generally hemispherical and hollow, and creates a first output head chamber. The equatorial end of the first output head is coupled to the first output tube sheet opposite the second output head. The first output head has a first output head outlet.
In the heat exchanger, each of the individual tubes pass through a unique hole of the holes in the second input and output tube sheets. The tubes in a second tube set are sized such that an interior of the tubes in said second tube set is open to the second input head chamber and second output head chamber allowing NGLs to pass from head chamber to head chamber. Likewise, the tubes in the first tube set are sized such that an interior of said tubes in said first tube set is open to the first input head chamber and the first output head chamber. Any gaps between the tubes in the tube bundle or tube sets and the holes in the various tube sheets are sealed to keep different NGLs from mixing.
A third input tube sheet may be coupled between the others. For example, third input tube sheet may be coupled to the first end of the shell across the first aperture. The third input tube sheet has a multiplicity of holes the number of which corresponds with the number of the tubes in the shell. The third input head is cylindrical and hollow, and creates a third input head chamber. The first end of the third input head is coupled to the third input tube sheet opposite the shell. The third input head has a third input head inlet. Likewise, a third output tube sheet is coupled to the second end of the shell across said second aperture, wherein the third output tube sheet has a multiplicity of holes the number of which corresponds with the number of the tubes in the tube bundle. The third output head, again cylindrical and hollow, creates a third output head chamber. The first end of the third output head is coupled to the third output tube sheet opposite the shell. The third output head has a third output head inlet. The tubes in the first tube set are sized such that an interior of the tubes in the first tube set is open to the third input head chamber and the third output head chamber. As with the other tube sheets, any gaps between the tubes in the tube bundle and the holes in the third input and third output tube sheets are sealed.
Referring to the figures,
The tube bundle 62 is the collection of the multiplicity of tubes (56, 58, 60) inside of which the various tube side products (not shown) pass through the shell 12. The tubes (56, 58, 60) of the tube bundle 62 is secured by the tube sheets (42, 44, 46, 48) at their opposite ends. The tubes (56, 58, 60) are organized within the tube bundle 62 by being inserted through tube sheet apertures 54 in the tube sheets (42, 44, 46, 48) and secured there. The inner sides of the tube sheets (42, 44, 46, 48) are toward the inside of the shell, while the outer sides of the tube sheets (42, 44, 46, 48) are toward the heads (14, 16, 18, 20) of the heat exchanger 10.
Along the length of the tube bundle 62 one or more baffles 64 may be placed. The main roles of a baffle 64 in a shell 12 of the tube heat exchanger 10 are to hold the tubes (56, 58, 60) in position (preventing sagging), and to promote cross-wise movement of the shell side product (not shown) in addition to the length-wise move of the shell side product (not shown) within the shell 12, and thus increase heat transfer between the shell side product (not shown) and the tube side products (not shown) in the tubes (56, 58, 60).
Again, as illustrated in
However,
Additional paired input and output heads (and their associated tube sheets and tubes) can be integrated into the improved heat exchanger 10, up until the diameter of the restricts the addition of more tubes, or the addition of additional paired input and output heads is limited by the number of tubes that fit in the shell 12, are in communication (or associated with) with the paired input and output heads, and are sufficient to provide for heat exchange at an efficiency acceptable to the user.
Exiting the coalescing filter separator 86, the hydrocarbon liquid passes through a transfer pipe 100 until it arrives at a junction with a thermostatically controlled temperature valve 88. The purpose of the control valve 88 is to control set-point temperature. Thermostatically controlled temperature valves 88 provide automatic and accurate temperature control of fluids. These self-contained, 3-way temperature control regulating valves 88 may be used in either mixing or diverting applications and require no external power source.
Exiting the 3-way temperature valve the hot gas is directed to pipe 102 or to pipe 106 depending on set temperature. If the hot gas is directed through pipe 102, it next enters the heat exchanger 74 through shell side inlet 38, the hot shell side gas now travels the full length of the heat exchanger exchanging heat with the tube side gas and the tube side NGL traveling in the opposite direction, the shell side gas exits outlet 40 at a reduced temperature. The gas then travels through pipe 104 where it enters the JT Valve.
The Joule-Thomson effect in theory, is a thermodynamic process that occurs when a fluid expands from high pressure to low pressure at constant enthalpy. Such a process can be approximated in the real world by expanding a fluid from high pressure to low pressure across a valve. Under the right conditions, this can cause cooling of the fluid.
Gas passes through JT valve 90 causing a pressure and temperature drop, the temperature causes some of the heaver hydrocarbons and water in the gas stream to condense into liquid phase. The gas stream is allowed into cold separator 92 through the cold separator inlet 94. After entering the cold separator the velocity of the two phase gas stream is slowed in the larger diameter cold separator allowing the hydrocarbon liquids 108 and water to separate from the lighter hydrocarbon gas 110, the liquids fall to the bottom of the cold separator where it is periodically dumped. The NGL exits through cold separator NGL outlet 112. After traveling through pipe 116, the NGL enters heat exchanger end cap inlet 26. The NGL stream is separated through multiple NGL tubes 56 which are secured and pass through corresponding holes in NGL tube sheet 42 which serves to separate the NGL side from the shell side gas, after passing through tube sheet 42 the cold NGL passes channel head 18. The NGL leaves channel head 18 and passes through tube sheet 46, the NGL now travels the full length of the heat exchanger cooling the hotter shell side gas as it travels in the opposite direction. From cold separator gas outlet 114 the now colder gas travels through pipe 118 and enters heat exchanger channel head 18 through channel head inlet 30, after entering channel head the gas is separated and passed through multiple gas tubes 58 which are secured through corresponding holes in tube sheet 46, which serves to separate the tube gas stream from the shell side gas stream, after passing through tube sheet 46 the cold gas now travels through the multiple tubes the full length of the heat exchanger as it cools the hotter shell side gas traveling in the opposite direction, the tube side gas now passes through tube sheet 48 entering channel head 20 then exits channel head outlet 32, the treated fuel grade gas now exits the fuel conditioning skid through pipe 122.
In interpreting the claims appended hereto, it is not intended that any of the appended claims or claim elements invoke 35 U.S.C. 112(f) unless the words “means for” or “step for” are explicitly used in the particular claim.
It should be understood that, although exemplary embodiments are illustrated in the figures and description, the principles of the present disclosure may be implemented using any number of techniques, whether currently known or not. The present disclosure should in no way be limited to the exemplary implementations and techniques illustrated in the drawings and description herein. Thus, although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limited sense. Various embodiments may include some, none, or all of the enumerated advantages. Various modifications of the disclosed embodiments, as well as alternative embodiments of the inventions will become apparent to persons skilled in the art upon the reference to the description of the invention. It is, therefore, contemplated that the appended claims will cover such modifications that fall within the scope of the invention. Modifications, additions, or omissions may be made to the systems, apparatuses, and methods described herein without departing from the scope of the disclosure. For example, the operations of the systems and apparatuses disclosed herein may be performed by more, fewer, or other components in the methods described may include more, fewer, or other steps. Additionally, steps may be performed in any suitable order.
This application is based upon and claims priority from U.S. Provisional application Ser. No. 62/589,355, filed Nov. 21, 2017 and 62/621,291, filed Jan. 24, 2018, which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62589355 | Nov 2017 | US | |
| 62621291 | Jan 2018 | US |
