Patent Description:
Rod baffle heat exchangers were created in <NUM> by Philips Petroleum Company to eliminate flow-induced vibrations in a plate baffle heat exchanger. Rod baffle heat exchangers are shell and tube type heat exchangers utilizing rod baffles to support the tubes and secure them against vibrations. Additionally, rod baffles can be used to correct shell-side flow distributions and to create a more turbulent shell-side flow. The term "baffle" refers to an annular ring in which the ends of a plurality of support rods are connected; hence the term "rod baffle". Examples of rod baffle heat exchangers may be found in, for example, <CIT> and <CIT>.

As shown in <FIG>, a conventional rod baffle heat exchanger, such as a shell and tube heat exchanger <NUM>, may include a rod baffle tube bundle <NUM> surrounded by a shell <NUM>. Tubes <NUM> in the tube bundle <NUM> are supported by a plurality of rod baffle assemblies <NUM>, <NUM>, <NUM>, and <NUM>. One fluid enters the shell-side of the shell and tube heat exchanger <NUM> through an inlet <NUM> and after heat exchange with the fluid in tubes <NUM> leaves the shell-side via outlet <NUM>. The fluid flowing through the tube side of the heat exchanger enters the end cap <NUM> of the heat exchanger via inlet <NUM> and leaves the end cap <NUM> of the heat exchanger via outlet <NUM>. Thus, fluid flows from end chamber <NUM>, which is defined by end cap <NUM> of the heat exchanger <NUM> and tube sheet <NUM>, through the tubes <NUM> and into the opposite end chamber <NUM>, which is similarly defined by the end cap <NUM> and the other tube sheet <NUM>.

<CIT> describes a vertical baffle heat exchanger comprising a casing, a tube sheet, a heat exchange tube bundle, multiple supporting strips arranged on the periphery for fixing the heat exchange tube bundle, and a plurality of notched longitudinal partitions disposed in the casing. These partitions may have a notch width and a pitch that are adjustable.

In one aspect, the present disclosure relates to a vertical rod baffle heat exchanger as defined in claim <NUM>. Embodiments of the vertical rod baffle heat exchanger may be used for heat removal, condensation operations, electricity generation, petrochemical plants, waste heat recovery, and other industrial applications.

In one or more embodiments, the vertical rod baffle heat exchanger may further include a plurality of support bars arranged on a circumference of the shell adapted to fix the tube bundle and be a slideway for the plurality of rod baffle rings. The plurality of support bars may be spaced apart from each other and rotated in <NUM>-degree increments around a circumference of the plurality of rod baffle rings. A non-condensable gas outlet may be provided at a similar level close to the tube-sheet on the shell as a vapor inlet. A liquid seal cylindrical section may be provided close to an elbow section on the shell side. An impingement plate may be provided in the shell to distribute incoming vapor from the inlet.

In some embodiments, the plurality of rod baffle rings may have a set of four rod baffle rings: a first rod baffle ring having a plurality of lateral rod baffles extending from an inner surface of the first rod baffle ring, a second rod baffle ring having a plurality of longitudinal rod baffles extending from an inner surface of the second rod baffle ring, a third rod baffle ring having a plurality of lateral rod baffles extending from an inner surface of the third rod baffle ring, and a fourth rod baffle ring having a plurality of longitudinal rod baffles extending from an inner surface of the fourth rod baffle ring. The vertical rod baffle heat exchanger may include at least four sets of four rod baffle rings. Additionally, a fifth set of four rod baffle rings may include two of the first rod baffle rings, the third rod baffle ring, and the fourth rod baffle ring. Each of the plurality of rod baffle rings may be evenly spaced a distance from an adjacent rod baffle across a length of the U-tube bundle. Each of the six or more longitudinal partition plates may be a notched longitudinal partition plate. A width of each of the longitudinal partition plates may be between <NUM> to <NUM> millimeters.

In yet another embodiment, a distance between the longitudinal partition plates and a length of the notched longitudinal partition plates may be varied. A distance between a first longitudinal partition plate and a second longitudinal partition plate may be greater than a distance between the second longitudinal partition plate and a third longitudinal partition plate. The distance between the second longitudinal partition plate and the third longitudinal partition plate may be greater than a distance between the third longitudinal partition plate and a fourth longitudinal partition plate. The distance between the third longitudinal partition plate and the fourth longitudinal partition plate may be greater than a distance between the fourth longitudinal partition plate and a fifth longitudinal partition plate. The distance between the fourth longitudinal partition plate and the fifth longitudinal partition plate may be greater than a distance between the fifth longitudinal partition plate and a sixth longitudinal partition plate. The notched end of each notched longitudinal partition plate may be a vertical distance from the shell. The vertical distance of the notched longitudinal partition plates may progressively decrease from the first longitudinal partition plate to the sixth longitudinal partition plate.

Other aspects and advantages will be apparent from the following description and the appended claims, that define embodiments of the vertical rod baffle heat exchanger.

Embodiments of the present disclosure are described below in detail with reference to the accompanying figures. Like elements in the various figures may be denoted by like reference numerals for consistency. Further, in the following detailed description, numerous specific details are set forth in order to provide a more thorough understanding of the claimed subject matter. However, it will be apparent to one having ordinary skill in the art that the embodiments described may be practiced without these specific details. As used herein, the term "coupled" or "coupled to" or "connected" or "connected to" may indicate establishing either a direct or indirect connection and is not limited to either unless expressly referenced as such. As used herein, fluids may refer to slurries, liquids, gases, and/or mixtures thereof. Wherever possible, like or identical reference numerals are used in the figures to identify common or the same elements. The figures are not necessarily to scale, and certain features and certain views of the figures may be shown exaggerated in scale for purposes of clarification.

In one aspect, embodiments disclosed herein relate to a rod baffle heat exchanger for heat removal, condensation operations, electricity generation, petrochemical plants, waste heat recovery, and other industrial applications. The rod baffle heat exchanger may also be interchangeably referred to as a rod baffle condenser in the present disclosure. Additionally, the rod baffle heat exchanger may incorporate vertical baffles with vertical partition plates. The rod baffle heat exchanger may aid in the removal of polymerization heat in a cool loop. Further, the rod baffle heat exchanger may allow for a higher condensation efficiency compared to conventional condensers.

Conventional rod baffle heat exchangers in industrial applications are typically exceptionally large and heavy due to horizontal arrangement. Additionally, conventional vertical rod baffle heat exchangers use small and shorter longitudinal baffle plates. Conventional vertical rod baffle heat exchangers are not sufficient for the increased size and capacity of modern polymerization reactors. For example, conventional vertical rod baffle heat exchangers, when increased for size and capacity, may cause shutdowns due to too low of a liquid level and subsequently a short cut of vapor flow.

Accordingly, one or more embodiments in the present disclosure may be used to overcome such challenges as well as provide additional advantages over conventional rod baffle heat exchangers, as will be apparent to one of ordinary skill. In one or more embodiments, the rod baffle heat exchanger may increase a gas velocity around tubes in the rod baffle heat exchanger and increase the operational range with regards to heat exchange coefficient. Rod baffle heat exchangers, according to embodiments herein, may include prolonged baffle plates, allowing lower liquid levels to enlarge the operation range of the polymerization process. In one or more embodiments, the prolonged longitudinal baffle plates may reduce a risk of plant shutdowns during unexpected changes in cooling water temperature and allow to operate the plant with higher throughputs. The rod baffle arrangement in the heat exchanger provides improved vibration protection by the rod baffles being distributed more evenly. Additionally, the rod baffle heat exchangers may increase reliability and performance over cycles of operation. Overall, the rod baffle heat exchangers may minimize product engineering, risk associated with rod baffle manufacture, reduction of assembly time, hardware cost reduction, and weight and envelope reduction.

Rod baffle heat exchangers, according to embodiments herein, may include a number of longitudinal baffle plates to increase the vapor velocities, making the heat transfer more efficient. In a non-limiting example, the rod baffle heat exchanger may have six longitudinal baffle plates. In one or more embodiments, support for lateral and longitudinal rods of the rod baffle heat exchanger may be split and distributed more evenly to improve an anti-vibration effect. Further, a length of the longitudinal baffle plates may be increased to cover at least a full length of a U-bundle in order to increase an operational flexibility by maintaining a liquid seal even at low levels.

In one or more embodiments, the rod baffle heat exchanger may be a vertical rod baffle condenser with six or more prolonged longitudinal partition plates. The prolonged longitudinal partition plates may allow a higher condensation efficiency in the vertical rod baffle condenser by increasing the gas velocity around the tubes. In addition, the prolonged longitudinal partition plates may increase the operational range with regards to heat exchange coefficient by the prolonged baffle plates, which allow lower liquid levels.

Turning to <FIG> shows a top view of a rod baffle heat exchanger <NUM> in accordance with one or more embodiments of the present disclosure. The rod baffle heat exchanger <NUM> includes six or more longitudinal partition plates <NUM> and a tube bundle <NUM>. The six or more longitudinal partition plates <NUM> are inserted within the tube bundle <NUM>. The tube bundle <NUM> is surrounded by a shell <NUM>. A number of instrument nozzles <NUM> may be placed around the shell <NUM>. The instrument nozzles <NUM> may provide various measurements on the rod baffle heat exchanger <NUM> such as level measurements, temperature measurements, and other measurements in the rod baffle heat exchanger <NUM>. Additionally, a tube-sheet <NUM> is provided and may be provided on top of the six or more longitudinal partition plates <NUM>. In one or more embodiments, a distance D between the longitudinal partition plates <NUM> may be varied. In a non-limiting example, the distance D between a first longitudinal partition plate 101a and a second longitudinal partition plate 101b may be greater than the distance between the second longitudinal partition plate 101b and a third longitudinal partition plate 101c. The distance between the second longitudinal partition plate 101b and the third longitudinal partition plate 101c may be greater than the distance between the third longitudinal partition plate 101c and a fourth longitudinal partition plate 101d. The distance between the third longitudinal partition plate 101c and the fourth longitudinal partition plate 101d may be greater than the distance between the fourth longitudinal partition plate 101d and a fifth longitudinal partition plate 101e. The distance between the fourth longitudinal partition plate 101d and the fifth longitudinal partition plate 101e may be greater than the distance between the fifth longitudinal partition plate 101e and a sixth longitudinal partition plate 101f. It is further envisioned that a width W of each of the longitudinal partition plates <NUM> may have a value between <NUM> to <NUM>, such as <NUM>.

According to the present disclosure, at least one longitudinal partition plate <NUM> (e.g., one or more of the six or more longitudinal partition plates <NUM>) is a notched longitudinal partition plate <NUM> provided in the tube bundle <NUM>. The at least one longitudinal partition plate <NUM> has a notched end <NUM> that has a vertical distance Dn from the shell <NUM>. Each of the one or more notched longitudinal partition plates <NUM> may have such a notched end <NUM>. Each of the notched longitudinal partition plates <NUM> may have varied vertical distances Dn. The vertical distance Dn of the notched longitudinal partition plates <NUM> may progressively decrease from the first longitudinal partition plate 101a to the sixth longitudinal partition plate 101f. In a non-limiting example, the vertical distance Dn of the first longitudinal partition plate 101a may be greater than the vertical distance of the second longitudinal partition plate 101b. The vertical distance of the second longitudinal partition plate 101b may be greater than the vertical distance of the third longitudinal partition plate 101c. The vertical distance of the third longitudinal partition plate 101c may be greater than the vertical distance of the fourth longitudinal partition plate 101d. The vertical distance of the fourth longitudinal partition plate 101d may be greater than the vertical distance of the fifth longitudinal partition plate 101e. The vertical distance of the fifth longitudinal partition plate 101e may be greater than the vertical distance of the sixth longitudinal partition plate 101f. In some embodiments, the value of the vertical distance Dn is chosen such that there is enough area between the notched longitudinal partition plates <NUM> and the shell <NUM> for a vapor to pass into the next partition. Additionally, adjacent notched longitudinal partition plates <NUM> may be oriented <NUM> degrees such that each notched end <NUM> terminates the adjacent notched longitudinal partition plates <NUM> in an opposite direction from the shell <NUM>.

Still referring to <FIG>, an outlet <NUM> may be provided at a similar level (circumferential location), close to the tube-sheet <NUM> on the shell <NUM>, as the inlet <NUM>. The outlet <NUM> may be a non-condensable gas outlet and the inlet <NUM> may be a vapor inlet in some embodiments. From the inlet <NUM>, vapors may enter the rod baffle heat exchanger <NUM> and flow through a flow path (see block arrows F) defined by the six or more longitudinal partition plates <NUM> to exit through the outlet <NUM>. Additionally, a liquid seal cylindrical section <NUM> may be provided below an elbow section 109a of the rod baffle heat exchanger <NUM> on the shell <NUM>. The elbow section 109a may be a portion of the shell <NUM> forming the outlet <NUM> and the inlet <NUM>. Further, an impingement plate <NUM> may be installed in the shell <NUM> to distribute incoming vapor from the inlet <NUM>.

A plurality of tubes <NUM> extend in an axial direction within the tube bundle <NUM> such that the six or more longitudinal partition plates <NUM> partition the plurality of tubes <NUM> of the tube bundle <NUM>. The tube bundle <NUM> is a U-tube bundle such that the plurality of tubes <NUM> have a bend. It is further envisioned that the notched longitudinal partition plates <NUM> may extend a length in a radial direction such that the notched end <NUM> is within the tube bundle <NUM>. The radial length of the notched longitudinal partition plates <NUM> may be measured from an end attached to the shell <NUM> to the notched end <NUM>. A minimum longitudinal length of the notched longitudinal partition plates <NUM> is greater than a lowest point at which a tube <NUM> is provided in the U-tube bundle <NUM>. By extending the notched longitudinal partition plates <NUM> in a longitudinal direction to at least the end of the U-tube bundle, a lower liquid seal is achieved and an operating range of the rod baffle heat exchanger <NUM> is increased.

As shown in <FIG>, the rod baffle heat exchanger <NUM> includes a plurality of rod baffle rings <NUM>, <NUM>, <NUM>, <NUM> distributed along an axial axis Ax of the plurality of tubes (see <NUM> in <FIG>). For example purposes only, <FIG> is shown with four rod baffle rings <NUM>, <NUM>, <NUM>, <NUM>; however, the rod baffle heat exchanger <NUM> may have any number rod baffle rings without departing from the scope of the present disclosure. Additionally, a plurality of support bars <NUM> may be arranged on a circumference of the shell (see <NUM> in <FIG>), which may be used to fix the tube bundle (see <NUM> in <FIG>) and function as a slideway for the plurality of rod baffle rings <NUM>, <NUM>, <NUM>, <NUM>. In a non-limiting example, the rod baffle heat exchanger <NUM> may have four support bars <NUM> evenly spaced such that the support bars <NUM> may be in <NUM>-degree increments around a circumference of the plurality of rod baffle rings <NUM>, <NUM>, <NUM>, <NUM>.

In one or more embodiments, the plurality of rod baffle rings <NUM>, <NUM>, <NUM>, <NUM> may be provided in sets of four. The plurality of rod baffle rings <NUM>, <NUM>, <NUM>, <NUM> may be in a configuration to have each rod baffle ring rotated at <NUM>-degrees from an adjacent rod baffle ring. By staggering the plurality of rod baffle rings <NUM>, <NUM>, <NUM>, <NUM> at <NUM> degrees back and forth, the rod baffle heat exchanger <NUM> may eliminate a phenomenon of liquid accumulation and realize a high-flux flow of condensate on the plurality of tubes (see <NUM> in <FIG>). In a non-limiting example, the first rod baffle ring <NUM> in the set of four rod baffle rings may have a plurality of lateral rod baffles 111a extending from an inner surface 111b of the first rod baffle ring <NUM>. The second rod baffle ring <NUM> in the set of four rod baffle rings may have a plurality of longitudinal rod baffles 112a extending from an inner surface 112b of the second rod baffle ring <NUM>. The third rod baffle ring <NUM> in the set of four rod baffle rings may have a plurality of lateral rod baffles 113a extending from an inner surface 113b of the third rod baffle ring <NUM>. The fourth rod baffle ring <NUM> in the set of four rod baffle rings may have a plurality of longitudinal rod baffles 114a extending from an inner surface 114b of the fourth rod baffle ring <NUM>.

Now referring to <FIG>, in one or more embodiments, <FIG> shows a partial close-up top view of the plurality of tubes <NUM> being spaced by the lateral rod baffles 111a, 113a of the first and third rod baffle rings <NUM>, <NUM> and the longitudinal rod baffles 112a, 114a of the second and fourth rod baffle rings <NUM>, <NUM>.

As shown in <FIG>, the lateral rod baffles 111a, 113a pass through a gap 116a between adjacent tubes (<NUM>) in the X axis direction. The longitudinal rod baffles 112a, 114a pass through a gap 116b between adjacent tubes (<NUM>) in the Y axis direction. Additionally, the lateral rod baffles 111a, 113a may also pass through openings in the notched longitudinal partition plates (see <NUM> in <FIG>). By increasing a distance between the lateral and longitudinal rods, the flow of liquid condensate in the plurality of tubes <NUM> may be less restricted and the support of the plurality of tubes <NUM> may be more evenly distributed over the length of the plurality of tubes <NUM>.

Now referring to <FIG>, in one or more embodiments, <FIG> shows a partial view of the rod baffle heat exchanger <NUM>. As shown <FIG>, the plurality of tubes <NUM> may be in the tube bundle <NUM> such as a U-tube bundle extending a length L. One skilled in the art will appreciate how the U-tube bundle <NUM> allows the plurality of tubes <NUM> to bend, e.g., U-bend <NUM>, such that full length of the plurality of tubes <NUM> is greater than the length L of the U-tube bundle <NUM>. This allows the rod baffle heat exchanger <NUM> to have longer tubes <NUM> while remaining compact and decrease the overall footprint of the rod baffle heat exchanger <NUM>. Additionally, the inlet <NUM> is in an upper part on a front side of the tube bundle <NUM> while the outlet <NUM> is on a back side of the tube bundle <NUM>. It is further envisioned that the outlet <NUM> may have a smaller diameter than the inlet <NUM>.

As shown in <FIG>, in one or more embodiments, the rod baffle heat exchanger <NUM> may have <NUM> sets of the set of four rod baffle rings <NUM>, <NUM>, <NUM>, <NUM> as described in <FIG> such that there are <NUM> sets of the rod baffle rings with lateral rods and <NUM> sets of the rod baffle rings with longitudinal rods. In addition, the rod baffle heat exchanger <NUM> may include a fifth set of four rod baffle rings configured with two first rod baffle rings such that the order of rod baffle rings is <NUM>, <NUM>, <NUM>, <NUM>, accounting from a U-bend <NUM> in the U-tube bundle <NUM>. It is further envisioned that a low point of the U-bend <NUM> may match a lowest rod baffle ring in the rod baffle heat exchanger <NUM>. Each of the rod baffle rings <NUM>, <NUM>, <NUM>, <NUM> may be spaced a distance Drb from an adjacent rod baffle such the rod baffle rings <NUM>, <NUM>, <NUM>, <NUM> are evenly spaced across the length L of the U-tube bundle. Additionally, each of the rod baffle rings <NUM>, <NUM>, <NUM>, <NUM> may have a thickness T such that the rod baffle rings have a uniform thickness. It is further envisioned that a rear part <NUM> of the U-tube bundle may have an anti-vibration grid structure.

Claim 1:
A vertical rod baffle heat exchanger (<NUM>) comprising:
a shell (<NUM>);
a tube-sheet (<NUM>);
a tube bundle (<NUM>) having a plurality of heat exchange tubes (<NUM>) extending in an axial direction, wherein the tube bundle (<NUM>) is a U-tube bundle comprising a U-bend in the plurality of heat exchange tubes (<NUM>);
six or more longitudinal partition plates (<NUM>) extending within the tube bundle (<NUM>) in a radial direction of the shell (<NUM>) along a longitudinal direction of the shell (<NUM>), wherein at least one longitudinal partition plate (<NUM>) is a notched longitudinal partition plate (<NUM>) that has a notched end (<NUM>) at a vertical distance (Dn) from the shell (<NUM>); and
a plurality of rod baffle rings (<NUM>, <NUM>, <NUM>, <NUM>) provided along an axial length of the plurality of heat exchange tubes (<NUM>), wherein the plurality of rod baffle rings (<NUM>, <NUM>, <NUM>, <NUM>) have lateral rod baffles (111a, 113a) extending in an X axis in the radial direction and longitudinal rod baffles (112a, 114a) extending in an Y axis in the radial direction,
wherein the lateral rod baffles (111a, 113a) and the longitudinal rod baffles (112a, 114a) pass through gaps (116a, 116b) between every two adjacent tubes of the plurality of heat exchange tubes (<NUM>), and the lateral rod baffles (111a, 113a) pass through openings in the notched longitudinal partition plate (<NUM>), and
wherein the at least one notched longitudinal partition plate (<NUM>) extends a minimum length in the longitudinal direction that is greater than a lowest point at which a tube of the plurality of heat exchange tubes (<NUM>) is provided in the U-tube bundle (<NUM>), and
wherein the at least one notched longitudinal partition plate (<NUM>) extends a length in the radial direction to have the notched end (<NUM>) within the tube bundle (<NUM>).