Energy conversion equipment and waste heat recovery system

Abstract

The utility model provides an energy conversion device and a waste heat recovery system, the energy conversion device comprises a preheating section, an evaporation section and a separation section, the preheating section and the evaporation section are both of a shell-and-tube structure, and the evaporation section is located on the upper portion of the preheating section; the separation section is of a cavity structure with a cavity, a liquid collection bag is arranged at the lower part of the separation section, and a condensate discharge port is formed in the liquid collection bag; a tube pass inlet of the evaporation section is used for inputting high-temperature process gas, and a tube pass outlet is connected with an inlet of the separation section; an outlet of the separation section is connected with a tube pass inlet of the preheating section; a shell pass inlet of the preheating section is used for inputting a low-temperature circulating medium, and a shell pass outlet of the preheating section is connected with a shell pass inlet of the evaporation section through a communicating pipe; and a shell pass outlet of the evaporation section is used for outputting circulating medium steam. Two-stage heat energy recovery is arranged, so that the low-level energy recovery utilization rate is improved; the gas-liquid separation function is integrated, the universality is high, and scouring and abrasion to equipment are avoided; functional sections of waste heat, evaporation, gas-liquid separation and the like are integrated, so that the complexity of a process system is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of chemical equipment, and in particular to energy conversion equipment and a waste heat recovery system. Background Art

[0002] Low-level energy refers to energy that is not utilized in energy utilization equipment under certain economic and technical conditions, that is, excess and wasted energy. A large amount of low-level energy is inevitably generated during the process, including waste heat from high-temperature exhaust gases, waste heat from cooling media, waste heat from waste steam and wastewater, waste heat from high-temperature products and slag, waste heat from chemical reactions, waste heat from combustible waste gases, waste liquids, and waste materials, as well as residual pressure from high-pressure fluids. If this low-level waste heat is not utilized, it will result in a huge waste of energy, which is particularly prominent in large-scale industrial production.

[0003] For example, in the existing octanol production process, the raw material octenal undergoes a hydrogenation reaction to produce crude octanol. The distillation process of the crude octanol includes the following steps: first, it enters the octanol pre-distillation tower. This pre-distillation operation is carried out under vacuum, removing light components from the top of the tower, and the bottom product enters the octanol distillation tower. The octanol distillation tower then undergoes vacuum distillation and separation, removing heavy components from the bottom of the tower. The octanol product with a temperature of approximately 131°C is extracted from the top of the octanol distillation tower. This high-temperature vapor octanol needs to be condensed and cooled with circulating water before being transported to the octanol tank. The vapor octanol at a temperature of approximately 131°C contains a large amount of heat energy. Directly condensing and cooling it with circulating water would result in heat waste and consume a large amount of circulating water, which would result in significant energy waste, especially in large-scale continuous industrial production.

[0004] The main ways to utilize low-level energy include direct waste heat utilization, waste heat power generation, and comprehensive waste heat utilization. Currently, one way to directly utilize high-temperature process gases is to generate steam. Traditional evaporators that utilize low-level energy include various reboilers, most of which are shell-and-tube heat exchangers, mainly including kettle, siphon, forced circulation, and built-in types. These heat exchangers have a single function, and the amount of heat they can exchange is limited by specific process requirements, making it impossible to fully recover heat. In addition, traditional reboilers only have a shell-side cavity. If the temperature of the process medium is not high enough, the heat exchanger requires more heat exchange area, resulting in an excessively large external size. In addition, if the tube-side process medium is a two-phase medium containing waste liquid, a separate gas-liquid separation device is required to separate and recover the waste liquid, making the overall process system more complex. If the condensate generated after the low-level process gas heat exchange is retained in the system, it not only increases the system operating load, but the high flow rate of the gas-liquid two-phase medium can also cause erosion and abrasion on the equipment.

[0005] Therefore, there is an urgent need to develop a device that can solve the problem of waste heat recovery from low-potential heat sources with large thermal energy, low absolute temperature, and a heat source containing gas-liquid two-phase medium. Utility Model Content

[0006] In response to the deficiencies in the existing technology, the utility model discloses an energy conversion device and a waste heat recovery system, which can efficiently and fully reuse low-energy waste heat and recover condensate, which not only reduces equipment loss, but also improves the degree of equipment integration and reduces the difficulty of equipment and system operation.

[0007] In order to achieve the above technical objectives, on the one hand, the present invention provides an energy conversion device, which includes a preheating section, an evaporation section, and a separation section, wherein the preheating section and the evaporation section are both shell-and-tube structures, and the evaporation section is located above the preheating section; the separation section is a cavity structure having a cavity, a liquid collection bag is provided at the lower part thereof, and the liquid collection bag is provided with a condensate discharge port;

[0008] The tube-side inlet of the evaporation section is used to input high-temperature process gas, and the tube-side outlet thereof is connected to the inlet of the separation section; the outlet of the separation section is connected to the tube-side inlet of the preheating section;

[0009] The shell side inlet of the preheating section is used to input low-temperature circulating medium, and its shell side outlet is connected to the shell side inlet of the evaporation section through a connecting pipe; the shell side outlet of the evaporation section is used to output circulating medium vapor.

[0010] In the above technical solution, the evaporation section and preheating section of the shell and tube structure are arranged upper and lower, and the waste heat of the low-level energy heat source, condensate recovery and preheating, evaporation and steam output of the low-temperature circulating medium and other functional sections are integrated into one device, thereby improving the equipment integration and reducing the complexity of the process system; at the same time, the low-level energy recovery rate is improved by setting the technical feature of two-stage heat energy recovery in the evaporation section and the preheating section.

[0011] In addition, the above technical solution also integrates the function of gas-liquid separation, making the energy conversion equipment of this utility model not only suitable for recycling and utilizing single-phase high-temperature process gas, but also suitable for processing high-temperature process gas containing gas and liquid phases. In the specific process, the high-temperature process gas is first input into the tube side of the evaporation section to provide sufficient calorific value for the generation of circulating medium vapor in the shell side; then, after the initial cooling, the process gas condenses and enters the separation section. Under the guidance of the separation section, it is input into the tube side inlet of the preheating section below the evaporation section to preheat the low-temperature circulating medium newly input into the shell side. After being preheated in the preheating section, the circulating medium will be input into the preheating section through the connecting pipe connecting the shell side of the evaporation section and the shell side of the preheating section to undergo heat exchange and evaporation and finally obtain steam. If the high-temperature process gas is a two-phase medium, the condensate after initial cooling will be input into the separation section together and separated in the separation section. The relatively heavy components will be enriched in the liquid collection bag under the action of gravity and further output to the equipment through the condensate discharge port. The discharge of the condensate can avoid the abrasion of the equipment caused by the erosion of the gas-liquid two-phase medium; the relatively light components after separation will be input into the tube side of the preheating section to heat the low-temperature circulating medium newly input into the shell side.

[0012] In a further example of the present invention, the structures of the evaporation section, the preheating section and the separation section are optimized respectively, and the embodiment of the present invention shows the optimized technical features and technical effects.

[0013] On the other hand, the utility model proposes a waste heat recovery system including the above-mentioned energy conversion equipment, wherein the shell-side outlet of the evaporation section is connected to the steam compressor via a pipeline, and the outlet of the steam compressor outputs high-grade steam; a first switch valve is provided on the pipeline connected to the shell-side inlet of the preheating section; a first branch for discharging steam is provided on the pipeline connecting the energy conversion equipment and the steam compressor, and a third switch valve is provided on the first branch; the evaporation section is provided with a liquid level gauge, and the liquid level gauge is signal-connected with the steam compressor, the first switch valve, and the third switch valve.

[0014] In the actual process, low-grade steam is generally output from the shell-side outlet of the evaporation section of the above-mentioned energy conversion equipment. The preheating recovery system of the utility model connects the shell-side outlet of the evaporation section with the steam compressor, and produces high-grade steam from the outlet of the steam compressor, further improving the utilization value of low-grade energy.

[0015] In addition, by monitoring the liquid level of the shell side of the evaporation section and interlocking to regulate the flow of the upstream low-temperature circulating medium input and the operation of the downstream steam compressor, the liquid level gauge is equipped with automatic interlocking controls such as low liquid level interlock, low-low interlock, high liquid level interlock, and high-high interlock for waste heat recovery under different working conditions, thereby improving the safety and stability of the overall system operation and sustainably utilizing low-level energy to produce high-value, high-grade steam.

[0016] Compared with the existing technology, the beneficial effects of the present invention are as follows: the energy conversion equipment of the present invention is equipped with a two-stage heat recovery section, namely the preheating section and the evaporation section, which improves the low-level energy recovery rate; the integrated gas-liquid separation function is suitable for recovering waste heat from high-temperature process gases and has strong universality; gas-liquid separation can improve heat exchange efficiency and prevent erosion and abrasion of the equipment by the two-phase medium obtained after condensation; the present invention integrates the waste heat, evaporation and gas-liquid separation functional sections, which improves the integration of the functional sections and reduces the complexity of the process system. The waste heat recovery system including the above energy conversion equipment can continuously and stably produce high-quality, high-grade steam. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings constituting part of this application are provided to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0018] Figure 1 Showing a structural diagram of an energy conversion device of the utility model;

[0019] Figure 2 The figure shows a structural diagram of a preheating recovery system of the present invention.

[0020] The above drawings include the following reference numerals:

[0021] 1-preheating section, 2-evaporation section, 21-demister, 22-protrusion, 3-separation section, 31-liquid collecting bag, 32-anti-vortex device, 4-connecting pipe, 5-steam compressor, 61-first switch valve, 62-second switch valve, 63-third switch valve, 71-liquid level gauge, 72-thermometer, 73-pressure gauge, 8-support. DETAILED DESCRIPTION

[0022] To facilitate understanding of the present invention, the present invention will be described in more detail below, with preferred embodiments thereof given. However, it should be understood that these embodiments are merely for the purpose of further explanation and should not be construed as limiting the present invention in any form, i.e., they are not intended to limit the scope of protection of the present invention.

[0023] Unless otherwise defined, the technical terms used in the following examples have the same meanings as those commonly understood by those skilled in the art to which this invention belongs. The experimental reagents used in the following examples, unless otherwise specified, are all conventional biochemical reagents; the experimental methods described, unless otherwise specified, are all conventional methods.

[0024] In the description of this application, it should be understood that the terms "upper" and "lower" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on this application.

[0025] Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the technical features being referred to. Thus, a feature identified as "first," "second," or "third" may explicitly or implicitly include one or more of the features.

[0026] In this application, unless otherwise specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal connection between two components or interaction between two components. For those skilled in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0027] Example 1

[0028] An energy conversion device, such as Figure 1 As shown, the equipment includes a preheating section 1, an evaporation section 2 and a separation section 3, wherein the preheating section 1 and the evaporation section 2 are both shell and tube structures, and the evaporation section 2 is located at the upper part of the preheating section 1; the separation section 3 is a cavity structure with a cavity, and a liquid collecting bag 31 is provided at its lower part, and the liquid collecting bag 31 is provided with a condensate discharge port; the tube side inlet of the evaporation section 2 is used to input high-temperature process gas, and its tube side outlet is connected to the inlet of the separation section 3; the outlet of the separation section 3 is connected to the tube side inlet of the preheating section 1; the shell side inlet of the preheating section 1 is used to input low-temperature circulating medium, and its shell side outlet is connected to the shell side inlet of the evaporation section 2 through a connecting pipe 4; the shell side outlet of the evaporation section 2 is used to output circulating medium vapor.

[0029] It should be noted that in this embodiment, the shell sides of the two functional sections of the evaporation section 2 and the preheating section 1 are connected by a connecting pipe 4, and the evaporation section 2 is located above the preheating section 1, but this does not limit the spatial relative position relationship between the two. For example, the projected areas of the evaporation section 2 and the preheating section can overlap (e.g. Figure 1 ), at an angle of 90°, 180° or other angles, or partially overlapping, etc. The technical solutions thus formed are all within the protection scope of this utility model.

[0030] Optionally, supports 8 are provided in each of the evaporation section 2 and preheating section 1 to support the entire functional section and improve the stability of the equipment. Furthermore, the supports 8 near the connecting pipe 4 are fixed, while the supports 8 in other locations are sliding. This allows the equipment to be freely axially extended and retracted while preventing damage to the equipment caused by excessive deformation of the shell-side connecting pipe.

[0031] Optionally, the separation section 3 is connected to the evaporation section 2 and the preheating section 1 respectively by flanges, so that the connection between the functional sections is more stable, reducing the constraints of temperature difference deformation during equipment operation, and avoiding damage to the sealing performance of the separation section 3 body and the connecting flange due to uncoordinated deformation.

[0032] Example 2

[0033] Based on the energy conversion equipment shown in Example 1, this embodiment optimizes the structures of the evaporation section 2 and the preheating section 1.

[0034] Optionally, the evaporation section 2 and / or the preheating section 1 are tilted and tilted horizontally downward along the flow direction of the tube-side medium, thereby accelerating the flow of logistics in the shell side along the transmission direction, especially accelerating the flow of liquid materials in the shell side, and improving the efficiency of heat exchange and subsequent gas-liquid separation.

[0035] Further optionally, the evaporation section 2 and the preheating section 1 are horizontally inclined downward along the direction of water flow in the tube side with a slope of 1‰-10%. In the actual process, a suitable slope can be set according to specific working conditions.

[0036] Example 3

[0037] Based on the energy conversion equipment shown in Example 1, the evaporation section 2 and the preheating section 1 are both shell and tube structures, and can be shell and tube heat exchangers, plate heat exchangers, kettle heat exchangers, fixed tube plate shell and tube heat exchangers, floating head heat exchangers, U-shaped tube plate heat exchangers and other shell and tube structures.

[0038] Optionally, the preheating section 1 is a fixed tube plate heat exchanger. In the shell side of the preheating section 1, the newly input low-temperature circulating medium absorbs less heat and the amount of vaporized hot water is also less. The use of a fixed tube plate heat exchanger can promote full contact heat exchange and improve efficiency.

[0039] Optionally, the evaporation section 2 is a kettle-type heat exchanger. The vaporization amount of the circulating medium in the shell side of the evaporation section 2 is significantly increased. The use of the kettle-type heat exchanger can provide a larger evaporation space to facilitate the generation of steam.

[0040] Example 4

[0041] Based on the energy conversion equipment shown in Example 1, the shell side of the evaporation section 2 is provided with a protrusion 22, and the shell side outlet of the evaporation section 2 is provided on the protrusion 22. The setting of the protrusion 22 can provide a vaporization space for the shell side of the evaporation section 2, which can reduce the flow rate, achieve a better defoaming effect, and improve the stability of the evaporation process.

[0042] Example 5

[0043] Based on the energy conversion device shown in Example 1, this embodiment optimizes the structure of the evaporation section 2.

[0044] Optionally, a demister 21 is provided at the shell outlet of the evaporation section 2 to separate foam or liquid droplets generated during the evaporation process from the steam, thereby helping to ensure the purity of the steam and preventing liquid from being carried into subsequent process flows.

[0045] Example 6

[0046] Based on the energy conversion device shown in Example 1, this example optimizes the structure of the separation section 3.

[0047] Optionally, the condensate discharge port is a condensate discharge port with an anti-vortex device 32. By providing the anti-vortex device 32, the flow path and velocity distribution of the fluid can be changed, effectively preventing the generation of vortexes and further reducing energy loss.

[0048] The specific structure of the anti-eddy current device 32 in this embodiment is not limited. Those skilled in the art can select a device that can achieve the anti-eddy current effect according to needs, such as an anti-eddy current baffle, etc., and the protection scope of the present utility model is not limited thereby.

[0049] Example 7

[0050] Based on the energy conversion equipment shown in Example 1, this example demonstrates the process of low-level energy recovery using the energy equipment under specific working conditions. It should be noted that this process is only a preferred demonstration and does not limit the scope of protection of the present utility model.

[0051] In this embodiment, the condensation waste heat recovery of octanol gas phase is taken as an example, and low-temperature hot water is used as the circulating medium. The specific process of using the energy conversion equipment of the utility model includes:

[0052] Gaseous octanol at a temperature of approximately 131°C is fed into the shell side of evaporation section 2. After heat exchange with preheated hot water (feed temperature of approximately 110°C) in the shell side, the hot water reaches a temperature of approximately 113°C, and low-grade steam is output from the shell side. The condensate, cooled to approximately 128°C, enters separation section 3 and is separated from the condensed water in separation section 3. Subsequently, the condensate (mainly octanol) at approximately 128°C is fed into the tube side of preheating section 1. After heat exchange with newly fed hot water (approximately 92°C), the octanol is cooled to approximately 100°C and output from the tube side of preheating section 1.

[0053] Example 8

[0054] A waste heat recovery system includes the above-mentioned energy conversion equipment, wherein the shell-side outlet of the evaporation section 2 is connected to the steam compressor 5 via a pipeline, and the outlet of the steam compressor 5 outputs high-grade steam; a first switch valve 61 is provided on the pipeline connected to the shell-side inlet of the preheating section 1; a first branch for discharging steam is provided on the pipeline connecting the energy conversion equipment and the steam compressor 5, and a third switch valve 63 is provided on the first branch; the evaporation section 2 is provided with a liquid level gauge 71, and the liquid level gauge 71 is in signal communication with the steam compressor 5, the first switch valve 61, and the third switch valve 63.

[0055] Optionally, the first switch valve 61 is a liquid level regulating valve.

[0056] Optionally, the evaporation section 2 is further provided with a thermometer 72 and / or a pressure gauge 73 to monitor the temperature and pressure changes in the evaporation section 2 to improve the safety of the operation of the waste heat recovery system.

[0057] In this embodiment, low-grade steam output from the shell-side outlet of evaporation section 2 of the energy conversion equipment is pressurized by steam compressor 5 to produce high-grade steam. The liquid level gauge 71 in the shell-side of evaporation section 2 has display and alarm functions and is equipped with automated interlocking controls such as low-level interlock, low-low interlock, high-level interlock, and high-high interlock to ensure continuous and stable output of high-grade steam.

[0058] Optionally, when the liquid level meter 71 detects that the liquid level in the shell side of the evaporation section 2 is lower than the set normal liquid level value (adjustable), the opening of the alarm and interlock first switch valve 61 is increased, thereby increasing the flow rate of the newly input low-temperature circulating medium to regulate the normal operating liquid level of the evaporation section 2.

[0059] Optionally, when the liquid level detected by the liquid level meter 71 is lower than a set low value (adjustable), an alarm will be sounded to remind the operator to check whether there is a fault in the system and to eliminate the fault in time.

[0060] Optionally, when the liquid level meter 71 detects that the liquid level reaches or is lower than the set low value (adjustable), an alarm will be issued and the steam compressor 5 will be shut down and the third switch valve 63 will be opened to discharge the steam in the pipeline to facilitate equipment inspection.

[0061] Optionally, when the liquid level meter 71 detects that the shell side of the evaporation section 2 has also reached the set high value (adjustable), it will alarm and interlock the first switch valve 61 to close, and remind the operator to check whether there is a fault in the system and eliminate the fault in time.

[0062] Optionally, when the liquid level meter 71 detects that the liquid level reaches or exceeds a set high value (adjustable), an alarm will be sounded and the steam compressor 5 and the second switch valve 62 will be shut down in an interlocked manner to ensure the safety of the steam compressor and the waste heat recovery system.

[0063] It should be pointed out that most chemical companies now have DCS systems or PLC systems installed in their factories. The waste heat recovery system of the present invention can rely on the original system and add the devices and equipment for interlocking control to the original DCS system or PLC system to realize automatic interlocking control.

[0064] Example 9

[0065] Based on the waste heat recovery system shown in Example 8, this embodiment optimizes the structure of the low-temperature circulating medium input pipeline. Optionally, a second on-off valve 62 is provided on the pipeline connected to the shell-side inlet of preheating section 1. This second on-off valve 62 is in signal communication with a liquid level gauge 71. Furthermore, the first on-off valve 61 and the second on-off valve 62 can each be a liquid level regulating valve or an on-off valve. This ensures process safety through the coordinated operation of the two on-off valves in the event of a high-high interlock or low-low interlock condition.

[0066] It should be noted that the above content is a further detailed description of the present invention in conjunction with specific implementation methods, and the specific implementation of the present invention cannot be considered to be limited to these descriptions; the dimensional data of this embodiment does not limit the technical solution of this invention, but only illustrates one specific working condition. For those skilled in the art of the present invention, simple improvements and modifications can be made without departing from the concept of the present invention, and all of these should be considered to fall within the scope of protection of the present invention.

Claims

1. An energy conversion device, characterized in that: The invention comprises a preheating section (1), an evaporation section (2) and a separation section (3), wherein the preheating section (1) and the evaporation section (2) are both shell-and-tube structures, and the evaporation section (2) is located above the preheating section (1); the separation section (3) is a cavity structure with a cavity, and a liquid collecting bag (31) is provided at the lower part thereof, and the liquid collecting bag (31) is provided with a condensate discharge port; The tube-side inlet of the evaporation section (2) is used to input high-temperature process gas, and the tube-side outlet thereof is connected to the inlet of the separation section (3); the outlet of the separation section (3) is connected to the tube-side inlet of the preheating section (1); The shell-side inlet of the preheating section (1) is used to input low-temperature circulating medium, and its shell-side outlet is connected to the shell-side inlet of the evaporation section (2) through a connecting pipe (4); the shell-side outlet of the evaporation section (2) is used to output circulating medium vapor.

2. The energy conversion device according to claim 1, characterized in that The evaporation section (2) and / or the preheating section (1) are arranged obliquely and tilted horizontally downward along the flow direction of the tube-side medium.

3. The energy conversion device according to claim 2, characterized in that: The evaporation section (2) and / or the preheating section (1) have an inclination gradient of 1‰-10%.

4. The energy conversion device according to claim 1, characterized in that The preheating section (1) and the evaporation section (2) are independently selected from a shell and tube heat exchanger, a plate heat exchanger, a kettle heat exchanger, a fixed tube sheet shell and tube heat exchanger, a floating head heat exchanger or a U-shaped tube sheet heat exchanger.

5. The energy conversion device according to claim 1, characterized in that: The shell side of the evaporation section (2) is provided with a protrusion (22), and the shell side outlet of the evaporation section (2) is provided on the protrusion (22).

6. The energy conversion device according to claim 1, characterized in that: A demister (21) is provided at the shell-side outlet of the evaporation section (2).

7. The energy conversion device according to claim 1, characterized in that: The condensate discharge port is a condensate discharge port with an anti-vortex device (32).

8. A waste heat recovery system comprising the energy conversion device according to any one of claims 1 to 7, characterized in that: The shell-side outlet of the evaporation section (2) is connected to a steam compressor (5) via a pipeline, and the outlet of the steam compressor (5) outputs high-quality steam; A first switch valve (61) is provided on the pipeline connected to the shell-side inlet of the preheating section (1); a first branch for discharging steam is provided on the pipeline connecting the energy conversion device and the steam compressor (5), and a third switch valve (63) is provided on the first branch; The evaporation section (2) is provided with a liquid level meter (71), and the liquid level meter (71) is in signal communication with the steam compressor (5), the first switch valve (61), and the third switch valve (63).

9. The waste heat recovery system of the energy conversion equipment according to claim 8, characterized in that: A second switch valve (62) is also provided on the pipeline connected to the shell side inlet of the preheating section (1), and the second switch valve (62) is in signal communication with the liquid level meter (71).

10. The waste heat recovery system of the energy conversion equipment according to claim 8, characterized in that: The evaporation section (2) is also provided with a thermometer (72) and / or a pressure gauge (73).

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