Rotary heat exchanger system with split rotor

Abstract

The utility model relates to a rotary heat exchanger system. The rotary heat exchanger system comprises a first rotor, a second rotor and a third rotor, wherein the first rotor is provided with a first heat exchange element configured to receive process fluid and working fluid; a first shaft coupled to the first rotor; a second rotor with a second heat exchange element configured to receive the process fluid and the working fluid; and a second shaft separated from the first shaft and coupled to the second rotor. The first shaft is configured to rotate to place the process fluid and the working fluid in a heat exchange relationship, and the second shaft is configured to rotate to place the process fluid and the working fluid in an additional heat exchange relationship. Further, the second rotor is offset from the first rotor along a flow path of the process fluid and the working fluid between the first rotor and the second rotor.

Description

Technical Field

[0001] The present disclosure relates to the field of rotary heat exchangers, and in particular to a rotary heat exchanger with multiple separate rotors. Background Art

[0002] Rotary heat exchangers or rotary machines are generally used to regulate gas flows. A rotary heat exchanger includes a rotor through which different gas flows (such as a hot gas flow and a cold gas flow) are directed and / or across. In some embodiments, the rotor places the hot gas flow and the cold gas flow in a heat exchange relationship to exchange heat between the hot gas flow and the cold gas flow, such as to heat the cold gas flow to a desired temperature. Such heat transfer reduces the temperature of the hot gas flow, which may cause condensation of some particles in the hot gas flow. Some of the particles may be trapped in the rotor, which may reduce the heat transfer efficiency of the rotor and / or reduce the structural integrity of the rotor by reducing the gas flow through the rotor. In either case, the heat exchange of the rotor between the hot gas flow and the cold gas flow may be negatively affected. Utility Model Content

[0003] The present disclosure relates to a rotary heat exchanger system. For example, according to an embodiment, the present disclosure may relate to a rotary heat exchanger system, comprising: a first rotor with a first heat exchange element configured to receive a process fluid and a working fluid; a first shaft coupled to the first rotor; a second rotor with a second heat exchange element configured to receive a process fluid and a working fluid; and a second shaft separated from the first shaft and coupled to the second rotor. The first shaft is configured to rotate so that the process fluid and the working fluid are in a heat exchange relationship, and the second shaft is configured to rotate so that the process fluid and the working fluid are in an additional heat exchange relationship. Additionally, the second rotor is offset from the first rotor along a flow path of the process fluid and the working fluid between the first rotor and the second rotor.

[0004] These and other advantages and features will become apparent in view of the accompanying drawings and detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] In order to complete the description and to enable a better understanding of the present disclosure, a set of drawings is provided, in which like reference numerals refer to the same features throughout. The drawings form an integral part of the specification and illustrate embodiments of the present disclosure, which should not be interpreted as limiting the scope of the present disclosure, but only as an example of how to implement the present disclosure. The drawings include the following figures:

[0006] Figure 1 is a system schematic diagram of a rotary heat exchanger system according to an exemplary embodiment of the present application;

[0007] Figure 2is a side view of a rotary heat exchanger system having multiple rotors according to an exemplary embodiment of the present application;

[0008] Figure 3 According to an exemplary embodiment of the present application Figure 2 A side view of a first rotor of a rotary heat exchanger system;

[0009] Figure 4 According to an exemplary embodiment of the present application Figure 2 A side view of a second rotor of a rotary heat exchanger system;

[0010] Figure 5 is a flow chart of a method for operating a rotary heat exchanger system to remove particles from a rotor of a rotary heat exchanger system according to an exemplary embodiment of the present application; and

[0011] Figure 6 is a flow chart of a method for operating a rotor of a rotary heat exchanger system to limit particle accumulation in the rotor of the rotary heat exchanger system according to an exemplary embodiment of the present application. DETAILED DESCRIPTION

[0012] In general, the present disclosure relates to a rotary heat exchanger system. The rotary heat exchanger system is configured to regulate the flow of gas. For example, the rotary heat exchanger system is configured to transfer heat from a hot gas flow to a cold gas flow (e.g., to preheat the cold gas flow). To this end, the rotary heat exchanger system includes a first rotor and a second rotor. Each rotor in the rotor includes a heat exchange element, which is configured to absorb heat from the hot gas flow to heat the heat exchange element, and each rotor in the rotor is configured to rotate so that the heated heat exchange element moves to be exposed to the cold gas flow. Then, the heat exchange element discharges heat into the cold gas flow to heat the cold gas flow. The first pipe is configured to guide the hot gas flow from the first rotor to the second rotor, and the second pipe is configured to guide the cold gas flow from the second rotor to the first rotor. For this reason, the first rotor is configured to receive the hot gas flow before transferring heat from the hot gas flow to the cold gas flow, and the second rotor is configured to receive the cold gas flow before the cold gas flow receives heat from the hot gas flow. Thus, the first rotor may be exposed to a relatively higher temperature gas flow, and the second rotor may be exposed to a relatively lower temperature gas flow.

[0013] The sootblowing cleaning system is configured to remove particles from the heat exchange elements of the rotor to avoid particle accumulation, otherwise the particle accumulation will hinder the efficient movement of the hot gas flow and / or the cold gas flow through the rotary heat exchanger system. For example, cooling the hot gas flow may condense and solidify particles (e.g., ammonium bisulfate) contained in the hot gas flow, and such particles may be trapped in the heat exchange elements of any rotor, but especially the second rotor exposed to the relatively low temperature gas flow (e.g., to cause a greater possibility of solidifying particles in the hot gas flow). The entrapment of particles in the heat exchange element may block the opening through which the gas flow can be directed, thereby reducing the amount of gas (e.g., flow rate) directed through the rotor and reducing the heat transfer efficiency between the gas flows. In addition or alternatively, particles trapped in and contacting the heat exchange element may cause the heat exchange element to deteriorate and wear. In either case, the performance level of the rotary heat exchanger system may be reduced. Therefore, the use of a sootblowing cleaning system to remove such particles from the heat exchange element can help maintain the normal operation of the rotary heat exchanger system.

[0014] The first rotor and the second rotor are spaced apart from each other along the direction in which the hot gas flow and the cold gas flow are directed between the rotors so that the sootblowing and cleaning system performs effective sootblowing and cleaning on the first rotor and the second rotor. For example, the sootblowing and cleaning system may include a first sootblower and a second sootblower, the first sootblower being positioned adjacent to the second rotor and at least partially in the space between the first rotor and the second rotor, and the second sootblower being positioned adjacent to the second rotor and outside the space between the first rotor and the second rotor. The cooperative operation of the first sootblower and the second sootblower can provide relatively stronger cleaning, especially for the second rotor that may be more easily trapped in its heat exchange element. Additionally, spacing the first rotor and the second rotor apart from each other can enable particles to be removed from the second rotor and not be directed toward the first rotor and not likely to be trapped in the heat exchange element of the first rotor. In this way, the second rotor can be better cleaned to improve the operation of the second rotor without reducing the operation of the first rotor.

[0015] In addition, the first rotor and the second rotor are operated by a separated shaft. That is, the first rotor is coupled to a first shaft configured to rotate the first rotor, the second rotor is coupled to a second shaft configured to rotate the second rotor, and the first shaft and the second shaft are separated from each other. In this way, the first rotor and the second rotor can be rotated independently by the shaft. In other words, the rotation of the first rotor (e.g., rotation speed, rotation direction) can be achieved via the first shaft without mechanically affecting or driving the rotation of the second rotor, and the rotation of the second rotor (e.g., rotation speed, rotation direction) can be achieved via the second shaft without mechanically affecting or driving the rotation of the first rotor. Therefore, the rotation of each rotor can be separately controlled to provide a more suitable heat transfer function, such as to control the rate or amount of heat transfer provided at each rotor. In addition, the separation of the rotors enables the use of rotors of different types or sizes. For example, the second rotor can be relatively smaller than the first rotor (e.g., the second rotor can define a relatively smaller opening) so that the gas can flow through the second rotor at a greater speed. Compared with the gas flow at the first rotor, the increase in the speed of the gas flow through the second rotor can enable a greater amount of heat transfer between the gas flow at the second rotor. Thus, the relative differences between the rotors may further enable the rate or amount of heat transfer provided at each rotor to be controlled.For this reason, the separation of the rotors may enable the rotary heat exchanger system to be operated to more appropriately exchange heat between gas streams.

[0016] Figure 1 An example power plant 10 of the type that may incorporate a rotary heat exchanger 12 with heat exchange elements according to the present disclosure is illustrated in . The power plant 10 includes a generator 14 coupled to a steam turbine 16 to generate electricity. The steam turbine 16 is driven by steam from a boiler 18, which receives air for combustion via an air inlet 20 and exhausts combustion gases via an exhaust 22. Fans 24a and 24b may be used to supply air to the boiler air inlet 20, and to draw the combustion gases from the exhaust 22 through a dust removal system 26 before releasing the combustion gases to the atmosphere. A rotary heat exchanger 12 with the characteristics discussed herein may be positioned adjacent to the air inlet 20 and exhaust 22 to preheat the air entering the boiler 18 using heat from the combustion gases exhausted from the boiler 18. Rotary heat exchangers may also be used in gas-to-gas heaters to control emissions from a plant. Another implementation of the rotary heat exchanger 12 may include a mining operation to preheat very cold air (e.g., ambient air) entering the mine by using heat available in warmer exhaust air from the mine. Although the present disclosure primarily discusses implementations in rotary heat exchangers configured for heat exchange, it should be noted that the techniques discussed herein may be applied to any other suitable implementations, such as for transferring certain particles between fluids.

[0017] Reference now Figure 2, a side view of a rotary heat exchanger system 100 (e.g., rotary heat exchanger 12) is shown. The rotary heat exchanger system 100 (which may be a rotary air preheater) includes a rotor assembly 101 with a first rotor 102 and a second rotor 104. In addition, the rotary heat exchanger system 100 includes a first duct system 106 and a second duct system 108. The first duct system 106 is configured to direct a hot gas flow (e.g., flue gas, process fluid) through the rotary heat exchanger system 100 in a first direction 110, and the second duct system 108 is configured to direct a cold gas flow (e.g., ambient air, working fluid) through the rotary heat exchanger system 100 in a second direction 112 opposite to the first direction 110. For example, the first duct system 106 may include a first intake duct 114 configured to direct the hot gas flow into the rotor assembly 101 and through the first rotor 102, a first transition duct 116 configured to direct the hot gas flow from the first rotor 102 to the second rotor 104, and a first exhaust duct 118 configured to direct the hot gas flow through the second rotor 104 and out of the rotor assembly 101. The second duct system 108 may include a second intake duct 120 configured to direct the cold gas flow into the rotor assembly 101 and through the second rotor 104, a second transition duct 122 configured to direct the cold gas flow from the second rotor 104 to the first rotor 102, and a second exhaust duct 124 configured to direct the cold gas flow through the first rotor 102 and out of the rotor assembly 101. Thus, first rotor 102 is located upstream of second rotor 104 with respect to the flow path of hot gas flow from first rotor 102 to second rotor 104 , and second rotor 104 is located upstream of first rotor 102 with respect to the flow path of cold gas flow from second rotor 104 to first rotor 102 .

[0018] Each of the rotors 102, 104 includes a heat exchange element, and each of the rotors 102, 104 is configured to rotate to rotate the heat exchange element between the first duct system 106 and the second duct system 108 to exchange heat between the hot gas flow and the cold gas flow. For example, in a specific instance of operating the rotary heat exchanger system 100, a portion of the first rotor 102 may be aligned with the first duct system 106 (e.g., the first intake duct 114) to expose the heat exchange element of a portion of the first rotor 102 to the hot gas flow, thereby causing such heat exchange element to be heated. The rotation of the first rotor 102 changes the position of a portion of the first rotor 102, so that in a time period after the specific instance, the heat exchange element of the portion of the first rotor 102 is aligned with the second duct system 108 to expose such heat exchange element to the cold gas flow. Therefore, the heat exchange element discharges heat to the cold gas flow. In this way, the first rotor 102 transfers heat from the hot gas flow to the cold gas flow via its heat exchange element. Continued rotation of the first rotor 102 may change or alternate a portion between the first duct system 106 and the second duct system 108 to successively absorb heat from the hot gas flow and transfer heat to the cold gas flow, respectively.

[0019] The second rotor 104 can operate in a similar manner to transfer heat from the hot gas flow to the cold gas flow. That is, the second rotor 104 rotates so that a portion of the second rotor 104 alternates between the first piping system 106 and the second piping system 108 to be exposed to the hot gas flow and the cold gas flow, respectively. Therefore, the rotation of the second rotor 104 causes the heat exchange element of this portion of the second rotor 104 to absorb heat from the hot gas flow and transfer heat to the cold gas flow. As an example, the second piping system 108 can guide the cold gas flow through the second rotor 104 to cause the cold gas flow to receive an initial amount of heat from the hot gas flow (e.g., to heat the cold gas flow to a first temperature). Then, the second piping system 108 can guide the cold gas flow from the second rotor 104 to the first rotor 102 to cause the cold gas flow to receive an additional amount of heat from the hot gas flow (e.g., to heat the cold gas flow to a second relatively high temperature). At the same time, the first duct system 106 can direct the hot gas flow through the first rotor 102 to cause the hot gas flow to transfer some heat to the cold gas flow, and the first duct system 106 can direct the hot gas flow from the first rotor 102 to the second rotor 104 to cause the hot gas flow to transfer additional heat to the cold gas flow. Therefore, the rotor assembly 101 is a two-stage configuration, in which the rotors 102, 104 sequentially heat the cold gas flow and cool the hot gas flow.

[0020] In certain embodiments, the first rotor 102 is coupled to a first shaft 126 configured to rotate the first rotor 102, and the second rotor 104 is coupled to a second shaft 128 configured to rotate the second rotor 104. The first shaft 126 and the second shaft 128 are separated from each other. Therefore, the first shaft 126 is configured to rotate to mechanically drive the rotation of the first rotor 102 without mechanically driving the rotation of the second rotor 104, and the second shaft 128 is configured to rotate to mechanically drive the rotation of the second rotor 104 without mechanically driving the rotation of the first rotor 102. Therefore, the first shaft 126 and the second shaft 128 independently rotate the first rotor 102 and the second rotor 104, respectively. In the illustrated embodiment, the first shaft 126 and the second shaft 128 are colinear with each other along a common axis 130 so that the rotors 102, 104 are concentrically aligned with each other. In this way, the hot gas flow and the cold gas flow can be linearly guided along (e.g., parallel to) the axis 130 in the first direction 110 and the second direction 112, respectively.

[0021] As an example, the rotation of the shafts 126, 128 can be controlled to provide the desired heating of the cold air flow (e.g., to a threshold temperature) via the rotors 102, 104. For example, the rotary heat exchanger system 100 may include a control system 132 or be communicatively coupled to the control system. The control system 132 includes a memory 134 and a processor 136 (e.g., a processing circuit). The memory 134 includes a read-only memory (ROM), a random access memory (RAM), a disk storage media device, an optical storage media device, a flash memory device, an electrical, optical or other physical / tangible (e.g., non-transitory) memory storage device. Therefore, in general, the memory 134 includes one or more computer-readable storage media (e.g., a memory device) encoded with software with computer-executable instructions, which can be executed to implement the operations described herein. For example, the memory 134 stores or encodes instructions for operating the shafts 126, 128. The processor 136 includes, for example, a collection of microcontrollers and / or microprocessors, each of which is configured to execute corresponding software instructions stored in the memory 134. The processor 136 is configured to execute instructions stored in the memory 134 , for example, to start, pause, or adjust the rotation of each shaft 126 , 128 .

[0022] For example, the control system 132 may be configured to adjust the rotational speed of the shafts 126, 128 to adjust the amount of heat transferred from the hot gas flow to the cold gas flow at each rotor 102, 104. For example, the control system 132 may operate the shaft 126 to rotate the first rotor 102 at a first speed (e.g., a relatively low speed) and the second rotor 104 at a second speed (e.g., a relatively high speed) to cause the second rotor 104 to provide relatively more heat transfer from the hot gas flow to the cold gas flow than provided by the first rotor 102. The control system 132 is additionally or alternatively configured to adjust the rotational direction of the shafts 126, 128. For example, the control system 132 may operate the first shaft 126 to rotate the first rotor 102 about the axis 130 in a first rotational direction 138, and operate the second shaft 128 to rotate the second rotor 104 in a second rotational direction 140 opposite to the first rotational direction 138. However, the control system 132 may operate the first shaft 126 to rotate the first rotor 102 in the second rotational direction 140, and operate the second shaft 128 to rotate the second rotor 104 in the first rotational direction 138; and / or in certain embodiments, the control system 132 may operate the shafts 126, 128 to rotate the rotors 102, 104 in the same rotational direction. In fact, the control system 132 may operate in any suitable manner to control the amount of heat transferred from the hot gas flow to the cold gas flow via each rotor 102, 104. That is, the control system 132 may operate the shafts 126, 128 to sensitively control the heating of the cold gas flow, such as to reach a desired threshold temperature at each rotor 102, 104.

[0023] In certain embodiments, the control system 132 is communicatively coupled to a sensor 142 (e.g., representing one or more sensors) that is configured to indicate a temperature of the cold gas flow and / or the hot gas flow. As an example, the control system 132 may be configured to operate the shafts 126, 128 to increase the temperature of the cold gas flow to a first threshold temperature via the second rotor 104 and to a second threshold temperature via the first rotor 102. Thus, the control system 132 may operate the shafts 126, 128 based on the temperature of the cold gas flow indicated by the sensor 142 to adjust the rotation of the first rotor 102 and / or the rotation of the second rotor 104 to cause the second rotor 104 to transfer heat from the hot gas flow to the cold gas flow to heat the cold gas flow toward the first threshold temperature, and cause the first rotor 102 to transfer heat from the hot gas flow to the cold gas flow to heat the cold gas flow toward the second threshold temperature.

[0024] Additionally, in some embodiments, the rotors 102, 104 have different sizes and / or types to provide the desired heat transfer function. For example, the second rotor 104 can be relatively smaller than the first rotor 102 so that the gas can flow through the second rotor 104 at a relatively faster speed than the gas flow through the first rotor 102. The relatively faster flow speed of the gas through the second rotor 104 can enable a relatively greater heat transfer to be achieved at the second rotor 104. Therefore, rotors 102, 104 with specific characteristics can be more appropriately selected and implemented.

[0025] In such embodiments, the ducts 114, 116, 118, 120, 122, 124 may have different sizes (e.g., different cross-sectional areas) to accommodate the different sizes of the rotors 102, 104. For example, the first intake duct 114 and the second exhaust duct 124 may be relatively large to accommodate the relatively large first rotor 102, the first exhaust duct 118 and the second intake duct 120 may be relatively small to accommodate the relatively small second rotor 104, and the size of each of the first transition duct 116 and the second transition duct 122 may vary (e.g., the transition ducts 116, 122 may be tapered) to transition between the relatively large first rotor 102 and the relatively small second rotor 104. The different sizes of the ducts 114, 116, 118, 120, 122, 124 may more ideally direct the gas flow through the rotors 102, 104 (e.g., to avoid the gas flow around and bypassing the rotors 102, 104) to enhance heat transfer between the gas flows. In certain embodiments, the ducts 114, 116, 118, 120, 122, 124 may be separate components coupled to each other and / or to the rotors 102, 104. Separating the ducts 114, 116, 118, 120, 122, 124 may facilitate access to different components of the rotor assembly 101, such as to facilitate separation of the transition ducts 116, 122 from each other to access the space 144, for facilitating ease of inspection, monitoring, replacement and / or repair of different components of the rotor assembly 101. However, in additional or alternative embodiments, the respective ducts 114, 116, 118, 120, 122, 124 are integral and have portions of different sizes to accommodate rotors 102, 104 of different sizes.

[0026] Because the first rotor 102 is exposed to the hot gas flow that has not yet been cooled by heat exchange with the cold gas flow and to the cold gas flow that has been initially heated via the second rotor 104, the first rotor 102 may be at a relatively high temperature. In contrast, because the second rotor 104 is exposed to the cold gas flow that has not yet been heated by heat exchange with the hot gas flow and to the hot gas flow that has been cooled via the second rotor 104, the second rotor 104 may be at a relatively low temperature. The relatively low temperature at the second rotor 104 may cause the second rotor 104 to more easily trap solidified particles therein. For example, cooling the hot gas flow via the second rotor 104 may reduce the temperature of the hot gas flow to below a threshold temperature, which causes some particles contained in the second rotor 104 to condense, solidify, and precipitate. Such particles may be trapped in the heat exchange elements of the second rotor 104.

[0027] For this reason, the rotary heat exchanger system 100 includes a sootblowing cleaning system 200 (in Figure 3 and Figure 4 ), the sootblowing and cleaning system is configured to remove solidified particles (e.g., as well as other elements such as dust and / or debris) from the rotors 102, 104. In some embodiments, the sootblowing and cleaning system 200 includes one or more sootblowers configured to direct a fluid or air through the rotors 102, 104. Such a fluid may, for example, apply a force that causes solidified particles to move and move out of the rotors 102, 104. In this way, the rotors 102, 104 may be arranged to avoid undesirable movement of particles between the rotors 102, 104, which may cause particles to be trapped by one of the rotors 102, 104 and reduce the benefits provided by the operation of the sootblowing and cleaning system 200. To this end, the rotors 102, 104 may be offset or spaced apart from each other along the direction 110, 112 of the flow path of the gas between the rotors 102, 104, thereby providing a space 144 between the rotors 102, 104, and the transition ducts 116, 122 span the space to guide the gas flow between the rotors 102, 104. For example, the distance 146 between the rotors 102, 104 may be a value between 3 meters and 7 meters. Such a distance 146 may be large enough to prevent particles removed from the second rotor 104 by the sootblowing and washing system 200 from being directed to the first rotor 102 (e.g., and being trapped in the first rotor), and to prevent particles removed from the first rotor 102 by the sootblowing and washing system 200 from being directed to the second rotor 104 (e.g., being trapped in the second rotor). Instead, the removed particles may be more easily and simply directed away from the rotors 102, 104 and out of the rotors (e.g., and out of the rotor assembly 101). Therefore, even if particles may be trapped in the rotors 102, 104, the sootblowing and washing system 200 may remove particles so that the rotors 102, 104 can operate ideally.

[0028] Additionally or alternatively, the control system 132 is configured to adjust the operation of the shafts 126, 128 to maintain the temperature of the hot gas stream above a threshold temperature to reduce or limit solidification of particles contained in the hot gas stream. For example, the control system 132 may be configured to operate the first shaft 126 to rotate the first rotor 102 to transfer a first amount of heat from the hot gas stream to the cold gas stream and reduce the temperature of the hot gas stream to a first temperature (e.g., determined via the sensor 142). Then, the control system 132 may be configured to operate the second shaft 128 to rotate the second rotor 104 based on the first temperature to transfer a second amount of heat from the hot gas stream to the cold gas stream and reduce the temperature of the hot gas stream to a second temperature above the threshold temperature (e.g., determined via the sensor 142). That is, the control system 132 operates the shafts 126, 128 in coordination with each other (e.g., based on the temperature changes of the hot gas streams) so that the iterative cooling of the hot gas streams provided by the rotors 102, 104 avoids reducing the temperature of the hot gas streams below the threshold temperature.

[0029] In additional or alternative embodiments, the control system 132 is configured to adjust the operation of the shafts 126, 128 to avoid excessive temperature fluctuations of the hot gas stream. For example, excessive heat transfer between the hot gas stream and the cold gas stream may cause an uneven temperature distribution throughout the hot gas stream, such as too low a temperature of a portion of the hot gas stream that solidifies the particles. For this reason, the control system 132 can operate the shafts 126, 128 to provide a more gradual temperature reduction of the hot gas stream (e.g., and a corresponding more gradual temperature increase of the cold gas stream) to provide a more uniform temperature distribution and avoid too low a temperature that solidifies the particles in the portion of the hot gas stream. In either case, the shafts 126, 128 are operated to avoid the accumulation of particles, which would otherwise reduce the operating efficiency of the rotary heat exchanger system 100 (e.g., or would have to be removed by the soot cleaning system 200 to maintain the desired operation of the rotary heat exchanger system 100).

[0030] In further embodiments, one or more barriers 148 (e.g., splash guards, filters) are positioned in the space 144 between the rotors 102, 104. The barrier 148 is configured to block particle flow but enable gas to flow therethrough. In this way, the barrier 148 blocks undesirable particle flow (e.g., caused by operation of the sootblowing cleaning system 200) from one of the rotors 102, 104 to the other of the rotors 102, 104, but enables gas to flow between the rotors 102, 104. That is, the barrier 148 further helps prevent particles from being trapped in the rotors 102, 104 while enabling desired heat transfer between the gas streams.

[0031] The barrier 148, the separation of the rotors 102, 104, and the operation of the rotors 102, 104 may collectively reduce or limit the accumulation of particles in each rotor 102, 104. For this reason, the operation of the sootblowing and washing system 200 to remove particles from the rotors 102, 104 may be limited or reduced. In other words, because there may be fewer particles trapped in each rotor 102, 104, there may be less need to clean each rotor 102, 104 via the sootblowing and washing system 200. Reducing the operation of the sootblowing and washing system 200 may both reduce operating costs and reduce wear on the rotors 102, 104 (e.g., heat exchange elements), thereby extending the useful life of the rotors 102, 104.

[0032] Figure 3 1 is a side view of a portion of a rotary heat exchanger system 100, specifically showing details about a second rotor 104 arranged relative to a sootblowing and washing system 200. The sootblowing and washing system 200 includes a first sootblower 202 (e.g., a first sootblower, a first sprayer) and a second sootblower 204 (e.g., a second sootblower, a second sprayer). The first sootblower 202 extends on a first side 206 of the second rotor 104, and the second sootblower 204 extends on a second side 208 of the second rotor 104 opposite to the first side 206. Thus, the second rotor 104 extends between the sootblower 202, 204. In some embodiments, the sootblower 202, 204 is positioned within the first duct system 106. Thus, the sootblower 202, 204 extends on a portion of the second rotor 104 that is exposed to a hot gas flow. However, in additional or alternative embodiments, the sootblowers 202 , 204 may be positioned within the second ductwork 108 such that the sootblowers 202 , 204 extend over portions of the second rotor 104 that are exposed to the flow of cold gas.

[0033] Each of the sootblowers 202, 204 is configured to direct fluid through the second rotor 104, such as across and between the heat exchange elements 210 of the second rotor 104, thereby removing particles from the heat exchange elements 210. For example, the first sootblowers 202 may extend in the space 144 between the first rotor 102 and the second rotor 104 (e.g., within the first transition duct 116). In this way, the first sootblowers 202 direct fluid through the second rotor 104 and away from the first rotor 102. Therefore, particles removed from the second rotor 104 via the first sootblowers 202 may also be directed away from the first rotor 102 to avoid directing particles toward the first rotor 102 (e.g., and trapping particles therein). In addition, the second sootblowers 204 are positioned outside of the space 144 (e.g., within the duct 118) and direct fluid through the second rotor 104 and toward the space 144, thereby directing particles away from the second rotor 104 and toward the space 144. However, because the first rotor 102 is spaced apart from the second rotor 104, particles directed away from the second rotor 104 by the second sootblowers 204 may not reach the first rotor 102. As such, the offset between the rotors 102, 104 prevents or at least blocks particles from flowing from the second rotor 104 to the first rotor 102, thereby avoiding increased particle entrapment in the first rotor 102. Additionally, the use of multiple sootblowers may increase the cleaning provided to the second rotor 104, such as compared to the use of a single sootblower extending across one of the sides of the second rotor 104.

[0034] As discussed herein, the second rotor 104 can be smaller than the first rotor 102. For example, the heat exchange element 210 of the second rotor 104 can be relatively small, can define a relatively small opening, or can otherwise have a reduced area to enable flow therethrough to induce a greater flow velocity through the second rotor 104. For example, the heat exchange element 210 can enable fluid directed by the sootblowers 202, 204 to flow through the second rotor 104 at a sufficient velocity to facilitate removal of particles from the heat exchange element 210 and / or enable a gas flow (e.g., a hot gas flow) to be directed through the second rotor 104 at a velocity above a certain velocity to avoid entrapment of particles within the heat exchange element 210. In either case, the heat exchange element 210 helps limit the accumulation of particles in the second rotor 104.

[0035] Still further, the heat exchange elements 210 may be arranged to direct the gas through the second rotor 104 in different directions and / or to provide a certain amount (e.g., surface area) of contact between the heat exchange elements 210 and the gas. Such an arrangement may further adjust the heat transfer between the gas flows, such as to change the amount of heating provided by the second rotor 104 relative to the amount of heating provided by the first rotor 102. Thus, embodiments of the second rotor 104 with more appropriately arranged heat exchange elements 210 may be achieved.

[0036] Figure 4 is a side view of a portion of a rotary heat exchanger system 100, showing details about a first rotor 102 arranged relative to a sootblowing and washing system 200. In particular, a third sootblower 250 (e.g., a third sootblower, a third sprayer) of the sootblowing and washing system 200 extends over the first rotor 102. As an example, the third sootblower 250 extends between the rotors 102, 104, such as within the first transition duct 116 and / or within the second transition duct 122. The third sootblower 250 is configured to direct fluid through the first rotor 102 and away from the second rotor 104. As such, the third sootblower 250 is configured to remove particles from a heat exchange element 252 of the first rotor 102 by directing the particles away from the second rotor 104. Thus, operation of the third sootblower 250 may avoid directing particles toward the second rotor 104 (e.g., and trapping the particles therein). Although a single sootblower extends across the second rotor 104 in the illustrated embodiment, in additional or alternative embodiments, multiple sootblowers (eg, positioned at opposite sides of the first rotor 102 ) may extend across the first rotor 102 to enhance cleaning of the first rotor 102 .

[0037] The heat exchange element 252 of the first rotor 102 is relatively large, defines a relatively large opening, or otherwise has an increased area as compared to the heat exchange element 210 of the second rotor 104, enabling flow therethrough to cause a lower flow velocity through the first rotor 102. However, the heat exchange element 252 may enable the gas flow to be at a sufficient velocity to provide a desired amount of heat transfer and cause the fluid flow provided by the third soot blower 250 to be directed at a sufficient velocity to remove particles from the heat exchange element 252. Additionally, the heat exchange element 252 may be appropriately arranged to direct the gas through the first rotor 102 in different directions and / or provide a certain contact area between the heat exchange element 252 and the gas to vary the amount of heating provided by the first rotor 102 (e.g., relative to the amount of heating provided by the second rotor 104).

[0038] Figure 5 and Figure 6Each of the methods illustrates a corresponding method for operating a rotary heat exchanger system (e.g., rotary heat exchanger system 100). In some embodiments, the operations of each method are performed by the same entity (e.g., control system 132). In additional or alternative embodiments, the operations of each method are performed by different entities (e.g., by different control systems). It should also be noted that each method can be performed in a manner different from that depicted. For example, additional operations may be performed, and / or any of the depicted operations may not be performed, may be performed in a different manner, and / or may be performed in a different order. In addition, the corresponding operations of each method may be performed relative to each other in any suitable manner, such as sequentially (e.g., in response to each other) and / or simultaneously (e.g., in parallel with each other).

[0039] Figure 5 300 is a flow chart of a method for operating a rotary heat exchanger system to remove particles from a rotor. The rotary heat exchanger system is configured to exchange heat between a process fluid (e.g., a process stream) and a working fluid (e.g., a working gas stream) via a low-temperature rotor and a high-temperature rotor. The low-temperature rotor is exposed to a relatively cold fluid, and the high-temperature rotor is exposed to a relatively hot fluid. For example, each rotor may be configured to transfer heat from a process fluid to a working fluid, and the process fluid may flow sequentially from the high-temperature rotor to the low-temperature rotor, and the working fluid may flow sequentially from the low-temperature rotor to the high-temperature rotor. In this way, the high-temperature rotor is exposed to the process fluid before heat is transferred from the process fluid to the working fluid, and is exposed to the working fluid that has initially been heated by the low-temperature rotor. Additionally, the low-temperature rotor is exposed to the working fluid before the working fluid is heated by the process fluid, and is exposed to the process fluid to which some heat has been transferred by the high-temperature rotor to the working fluid.

[0040] At block 302, the low temperature rotor is rotated via a first shaft. At block 304, the high temperature rotor is rotated via a second shaft. The first shaft and the second shaft are separated from each other. For this reason, movement of the first shaft drives the rotation of the low temperature rotor without affecting the rotation of the high temperature rotor, and movement of the second shaft drives the rotation of the high temperature rotor without affecting the rotation of the low temperature rotor. That is, the shafts can independently drive the rotation of the rotors, such as rotating at different speeds and / or in different directions relative to each other.

[0041] Furthermore, the rotors are offset from each other along the flow path of the fluid between the rotors. For example, the shafts may be spaced apart so that the rotors coupled to the respective shafts are offset from each other. Thus, a space is provided between the rotors.

[0042] At block 306, the process fluid is directed through the high temperature rotor and then through the low temperature rotor. As an example, a first inlet conduit may direct the process fluid into the high temperature rotor, a first transition conduit may direct the process fluid from the high temperature rotor to the low temperature rotor, and a first exhaust conduit may direct the process fluid away from the low temperature rotor (e.g., out of a rotary heat exchanger system).

[0043] At box 308, the working fluid is directed through the low temperature rotor and then through the high temperature rotor. For example, the second intake duct may direct the working fluid into the low temperature rotor, the second transition duct may direct the working fluid from the low temperature rotor to the high temperature rotor, and the second exhaust duct may direct the working fluid away from the high temperature rotor (e.g., to a target process or recipient using the heated working fluid). The process fluid and the working fluid flow through the rotor so that the working fluid and the process fluid are in a heat exchange relationship to enable heat transfer between the fluids. As an example, the low temperature rotor may transfer an initial amount of heat from the process fluid to the working fluid to initially heat the working fluid, and the high temperature rotor may transfer an additional amount of heat from the process fluid to the working fluid to further heat the working fluid. Therefore, the low temperature rotor and the high temperature rotor are a two-stage configuration.

[0044] Cooling the process fluid may cause some particles contained in the process fluid to condense and solidify. Solidified particles may be trapped in the low temperature rotor and / or the high temperature rotor. At box 310, the sootblowing system is operated to remove such particles from the low temperature rotor and / or the high temperature rotor. For example, the sootblowing system may include a sootblower disposed on the opposite side of the low temperature rotor, and each sootblower may guide the fluid through the low temperature rotor to remove particles from the low temperature rotor. One of the sootblower is positioned in the space between the rotors and is configured to guide the fluid away from the high temperature rotor to avoid guiding particles from the low temperature rotor toward the high temperature rotor. Another sootblower is configured to guide the fluid toward the space between the rotors. However, the separation between the rotors can prevent or at least hinder the particles from being guided from the low temperature rotor to the high temperature rotor. In addition, another sootblower of the sootblowing system is positioned adjacent to the high temperature rotor and is configured to guide the fluid through the high temperature rotor to remove particles from the high temperature rotor. The sootblower is also positioned in the space between the rotors and is configured to guide the fluid away from the low temperature rotor to avoid guiding particles from the high temperature rotor to the low temperature rotor. In this way, operation of the sootblowing system removes particles from each rotor without directing particles from one rotor to another.

[0045] Figure 6is a flow chart of a method 350 for operating a rotor of a rotary heat exchanger system to reduce or limit particle accumulation in the rotor. At block 352, a first temperature of a process fluid at a high temperature rotor is determined. At block 354, a second temperature of the process fluid at a low temperature rotor is determined. For example, one or more sensors may be configured to measure the temperature of the process fluid at the rotor, and the temperature of the process fluid may be determined based on the readings provided by the sensors.

[0046] At box 356, based on the first temperature and / or the second temperature, the rotation of the high temperature rotor and / or the rotation of the low temperature rotor are adjusted, for example, by a control system. For example, it may be desirable to maintain the temperature of the process fluid above a certain temperature to avoid or limit the solidification of particles in the process fluid, thereby limiting the entrapment of solid particles in the rotor. To this end, the rotor may be operated to maintain the first temperature of the process fluid at the high temperature rotor above a first threshold temperature (e.g., a high threshold temperature) and / or to maintain the second temperature of the process fluid at the low temperature rotor above a second threshold temperature (e.g., a low threshold temperature). The rotation of the high temperature rotor is adjusted in response to determining that the first temperature of the process fluid is at or below the first threshold temperature. Additionally or alternatively, the rotation of the low temperature rotor is adjusted in response to determining that the second temperature of the process fluid is at or below the second threshold temperature. For example, the rotation speed may be adjusted (e.g., reduced) and / or the rotation direction may be adjusted to reduce the heat transfer between the process fluid and the working fluid. Because the rotors are driven by separate shafts, the rotation of one of the rotors may be more appropriately adjusted without affecting the rotation of the other rotor. Thus, the operation of the rotary heat exchanger system can be more sensitively controlled to reduce or limit the entrapment of particles in the rotor.

[0047] Additionally or alternatively, the rotation of the high temperature rotor and / or the rotation of the low temperature rotor is adjusted to avoid an uneven temperature distribution throughout the process fluid that may otherwise cause the temperature at portions of the process fluid to be sufficiently low to solidify the particles. For example, providing a more gradual temperature change of the process fluid (e.g., by causing each rotor to transfer a similar amount of heat between the process fluid and the working fluid, by causing a similar temperature decrease of the process fluid at each rotor) may avoid causing any portion of the process fluid to have a sufficiently low temperature. That is, a more gradual temperature change of the process fluid may result in a more uniform temperature distribution throughout the process fluid to cause each portion of the process fluid to be sufficiently elevated to limit solidifying particles. Thus, the accumulation of particles in the rotors may be further reduced.

[0048] Adjusting the rotation of the rotor based on the temperature of the process fluid to limit particle accumulation can also enable the operation of the sootblowing system to be reduced or limited while maintaining the desired operation of the rotary heat exchanger system. For example, because particles may not accumulate within the rotor as frequently, the sootblowing system may also be operated less frequently to remove particles and still maintain the desired state of the rotor to provide adequate heat transfer between the process fluid and the working fluid. Reducing the operation of the sootblowing system can reduce power consumption and wear of the rotor (e.g., by reducing wear on heat exchange elements for each rotor) to extend the useful life of the rotor.

[0049] It should also be understood that the rotary heat exchanger system or part thereof described herein may be made of any suitable material or combination of materials, such as metal or synthetic materials, including but not limited to plastics, rubber, their derivatives, and combinations thereof. The present disclosure is also intended to cover modifications and variations of the present disclosure that fall within the scope of the appended claims and their equivalents. For example, it should be understood that terms such as "left", "right", "top", "bottom", "front", "back", "side", "height", "length", "width", "upper", "lower", "interior", "exterior", "inside", "outside", etc., as may be used herein, only describe reference points and do not limit the present disclosure to any particular orientation or configuration. In addition, the term "exemplary" is used herein to describe examples or illustrations. Any embodiment described in an exemplary manner herein should not be interpreted as a preferred or advantageous embodiment, but should be interpreted as an example or illustration of a possible embodiment of the present disclosure.

[0050] Finally, when used herein, the term "comprises" and its derivatives (such as "comprising", etc.) should not be understood as excluding the possibility that the described and defined content may include additional elements, steps, etc. At the same time, when used herein, the term "approximately" and its family terms (such as "approximate", etc.) should be understood to indicate values ​​that are very close to those accompanying the above terms. That is, deviations from the exact value within reasonable limits should be accepted, because those skilled in the art will understand that such deviations from the indicated values ​​are inevitable due to measurement inaccuracies, etc. The same applies to the terms "about" and "around" and "substantially".

Claims

1. A rotary heat exchanger system, characterized in that: The rotary heat exchanger system comprises: a first rotor including a first heat exchange element configured to receive a process fluid and a working fluid; a first shaft coupled to the first rotor, wherein the first shaft is configured to rotate to place the process fluid and the working fluid in heat exchange relationship; a second rotor comprising a second heat exchange element configured to receive the process fluid and the working fluid, wherein the second rotor is offset from the first rotor along a flow path of the process fluid and the working fluid between the first rotor and the second rotor; and A second shaft, separate from the first shaft, is coupled to the second rotor, wherein the second shaft is configured to rotate to place the process fluid in additional heat exchange relationship with the working fluid.

2. The rotary heat exchanger system according to claim 1, characterized in that: The rotary heat exchanger system includes a third sootblower and a first sootblower extending in a space between the first rotor and the second rotor, wherein the third sootblower is configured to direct the working fluid through the first rotor in a direction away from the second rotor, and the first sootblower is configured to direct the process fluid through the second rotor in a direction away from the first rotor.

3. The rotary heat exchanger system according to claim 1, characterized in that: The rotary heat exchanger system includes a barrier positioned between the first rotor and the second rotor to prevent particles contained in the process fluid and / or the working fluid from flowing between the first rotor and the second rotor.

4. The rotary heat exchanger system according to claim 1, characterized in that: The rotary heat exchanger system includes a control system configured to operate the first shaft and the second shaft to rotate the first rotor and the second rotor, respectively, wherein the control system is configured to operate the first shaft to rotate the first rotor at a first speed, and the control system is configured to operate the second shaft to rotate the second rotor at a second speed different from the first speed.

5. The rotary heat exchanger system according to claim 4, characterized in that: The control system is configured to: determining a first temperature of the process fluid at the second rotor; determining a second temperature of the process fluid at the first rotor; as well as The first speed of the first rotor and / or the second speed of the second rotor is adjusted based on the first temperature and / or based on the second temperature to maintain a temperature of the process fluid above a threshold temperature.

6. The rotary heat exchanger system according to claim 4, characterized in that: The control system is configured to operate the first shaft and to operate the second shaft to rotate the first rotor and to rotate the second rotor, respectively, independently of each other.

7. The rotary heat exchanger system according to claim 1, characterized in that: The second rotor is positioned downstream of the first rotor relative to the flow path of the working fluid from the first rotor to the second rotor, and the second rotor is smaller than the first rotor.

8. The rotary heat exchanger system according to claim 1, characterized in that: The first shaft is offset from the second shaft along the flow path of the process fluid and the working fluid between the first rotor and the second rotor.

9. The rotary heat exchanger system according to claim 1, characterized in that: The rotary heat exchanger system includes a conduit positioned in a space between the first rotor and the second rotor, wherein the conduit is separated from a conduit system positioned outside the space, the conduit system being configured to direct the working fluid and / or the process fluid through the first rotor and the second rotor.

10. The rotary heat exchanger system according to claim 1, characterized in that: The rotary heat exchanger system includes a control system configured to operate the first shaft and the second shaft to rotate the first rotor and the second rotor, respectively, wherein the control system is configured to operate the first shaft to rotate the first rotor around an axis in a first rotational direction, and the control system is configured to operate the second shaft to rotate the second rotor around the axis in a second rotational direction opposite to the first rotational direction.

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