A cascade heat exchanger for preparing phenol and acetone

Abstract

The utility model discloses a cascade heat exchange device for preparing phenol and acetone belongs to heat exchange temperature control technical field, including oxidizer, preheater, feed pump and be used for cooling gaseous crude acetone's condenser, and the condenser includes shell and condenser pipe, feed pump transports cumene raw material, and makes cumene raw material enter oxidizer in proper order after passing through condenser pipe and preheater. The utility model uses oxidation feed pump and transports cumene raw material to condenser pipe, and makes the heat transfer of gaseous crude acetone to cumene raw material, on one hand, can realize the condensation of gaseous crude acetone, and cumene is also not easy to make condenser pipe scale as cooling medium, reduces the use of the dispersing agent of original heat exchanger, and on the other hand, cumene absorbs the heat of gaseous crude acetone and heats up, also reduced the energy consumption of preheater, realized the efficient cascade utilization of device internal energy, significantly reduced the comprehensive energy consumption of whole phenol acetone production device.

Description

Technical Field

[0001] This utility model relates to the field of heat exchange and temperature control technology, specifically to a cascade heat exchange device for preparing phenol and acetone. Background Technology

[0002] The phenol-acetone production technology utilizes the reaction of cumene and oxygen to produce phenol and acetone. Cumene is heated to 70-80°C using steam condensate in an oxidizing feed preheater before entering the oxidizer to react and produce cumene hydroperoxide. The gaseous material from the crude acetone column (i.e., the crude acetone distillation column) is cooled by circulating water in a condenser.

[0003] The above production process has the following problems: scale will form in the circulating water of the condenser of the crude acetone tower, resulting in poor heat exchange effect. It is necessary to regularly add chemicals to flush the circulating water pipeline. When the scaling is severe, high-pressure flushing is required. Under high load and low temperature, the heat load requirement of the preheater is large, resulting in low preheating temperature of cumene feed. Utility Model Content

[0004] To address the aforementioned technical shortcomings, the purpose of this invention is to provide a cascade heat exchanger for preparing phenol and acetone, which uses cumene to condense the crude acetone in the gas phase, thereby increasing the preheating temperature of cumene and improving energy utilization.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: The present invention provides a cascade heat exchange device for preparing phenol and acetone, including an oxidizer, a preheater, a feed pump, and a condenser for cooling the gaseous crude acetone, wherein the condenser includes: The outer casing has an air outlet pipe at its top, a liquid storage tank at its bottom, and an air inlet pipe on its lower side wall. A condenser tube is installed inside the outer casing, with its inlet and outlet ends extending out of the casing. The feed pump delivers cumene raw material, which then passes through a condenser and a preheater before entering the oxidizer.

[0006] Preferably, the condenser tube comprises: Liquid inlet connector, wherein a liquid inlet pipe is provided on the liquid inlet connector; A liquid outlet connector, wherein a liquid outlet pipe is provided on the liquid outlet connector; Multiple heat exchange tubes are connected between the inlet and outlet joints. After the cumene raw material enters the inlet joint from the inlet pipe, it flows through the multiple heat exchange tubes and is discharged from the outlet pipe of the outlet joint.

[0007] Preferably, the outer shell includes a cylindrical body and two connecting cylinders respectively disposed at the upper and lower ends of the cylindrical body. The diameter of the connecting cylinders is larger than the diameter of the cylindrical body, and the liquid inlet connector and the liquid outlet connector are respectively disposed inside the two connecting cylinders.

[0008] Preferably, a spiral guide is provided inside the cylinder, and the spiral guide forms a flow channel with the inner wall of the cylinder for the spiral ascent of the gas phase crude acetone.

[0009] Preferably, a plurality of the heat exchange tubes are inserted into the spiral guide member.

[0010] Preferably, the air inlet pipe is disposed on the side wall of the cylinder below the spiral guide.

[0011] Preferably, the bottom of the lower connecting cylinder is provided with an orifice plate and is sealed to the liquid storage tank via a flange.

[0012] Preferably, the liquid inlet connector has multiple connection holes that communicate with the inner cavity of the liquid inlet connector; the end of the heat exchange tube is sealed and installed in the connection holes, so that the inner cavity of the heat exchange tube communicates with the inner cavity of the liquid inlet connector.

[0013] Preferably, a plurality of heat-conducting plates are fixed on the heat exchange tube, and the heat-conducting plates are in the form of rings.

[0014] Preferably, the plurality of heat exchange tubes are arranged in parallel in the form of a tube bundle.

[0015] The beneficial effects of this utility model are as follows: This invention uses an oxidation feed pump to transport cumene raw material to the condenser tube, allowing the heat from the gaseous crude acetone to be transferred to the cumene raw material. On one hand, this achieves the condensation of the gaseous crude acetone, and cumene, as a cooling medium, is less likely to cause scaling on the condenser tube, reducing the use of dispersant in the original heat exchanger. On the other hand, the cumene absorbs the heat from the gaseous crude acetone and heats up, reducing the energy consumption of the preheater and achieving efficient cascade utilization of energy within the device, significantly reducing the overall energy consumption of the entire phenol-acetone production unit. The spiral guide component installed inside the cylinder forces the high-temperature gaseous crude acetone to flow along a spiral path. This not only significantly extends the flow path and residence time of the gaseous crude acetone within the cylinder, allowing for more time for heat exchange, but more importantly, the centrifugal force generated enhances the turbulence effect, effectively disrupting the heat transfer boundary layer on the heat exchanger tube wall, thereby significantly improving the convective heat transfer coefficient and increasing the condensation heat exchange efficiency. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is a perspective view of a condenser in a cascade heat exchanger for preparing phenol and acetone, provided as an embodiment of the present invention.

[0018] Figure 2 This is a top view of the condenser in this utility model.

[0019] Figure 3 for Figure 2 Sectional view at point AA.

[0020] Figure 4 for Figure 3 A magnified view of a portion of point A in the middle.

[0021] Figure 5 This is a perspective view of the condenser tube in this utility model.

[0022] Figure 6 This is a top view of the spiral guide vane and heat exchange tube in this utility model.

[0023] Explanation of reference numerals in the attached figures: 1. Outer shell; 11. Cylinder; 12. Connecting cylinder; 2. Liquid storage tank; 3. Air inlet pipe; 4. Condenser pipe; 41. Liquid inlet connector; 42. Liquid inlet pipe; 43. Liquid outlet connector; 44. Liquid outlet pipe; 45. Heat exchanger pipe; 5. Spiral guide component; 6. Orifice plate; 7. Heat-conducting fin. Detailed Implementation

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0025] Example 1 like Figures 1 to 6As shown, Embodiment 1 of this utility model provides a cascade heat exchanger for preparing phenol and acetone. The core of this device lies in the efficient condensation of high-temperature gaseous crude acetone and the use of its heat energy to preheat the cumene feedstock, achieving cascaded energy utilization. This utility model includes an oxidizer, a preheater, a feed pump, and a condenser specifically for cooling the gaseous crude acetone. The oxidizer, preheater, and feed pump utilize existing equipment.

[0026] The condenser housing 1 is made of stainless steel and is a vertically arranged pressure vessel. An outlet pipe is connected to the center of the top of housing 1 to discharge any remaining non-condensable gases after condensation. A liquid storage tank 2 is located at the bottom of housing 1 to collect the condensed liquid crude acetone. A horizontal inlet pipe 3 is located on the lower side wall of housing 1 to introduce a high-temperature gaseous crude acetone mixture.

[0027] The core heat exchange component of the condenser is the condenser tube 4, located inside the outer shell 1. Cumene feedstock serves as the cooling medium. Both the inlet and outlet ends of the condenser tube 4 extend out of the outer shell 1 and are connected to external pipes. A feed pump pumps ambient temperature cumene feedstock from the feedstock storage tank into the inlet end of the condenser tube 4. As cumene flows through the condenser tube 4, it indirectly exchanges heat with the high-temperature gaseous crude acetone in the outer shell 1, absorbing the heat released during condensation, thus significantly increasing its own temperature. Subsequently, this preheated cumene feedstock continues to flow into the preheater, where it is further heated to reach the precise feed temperature required for the oxidation reaction, and finally enters the oxidizer to participate in the reaction.

[0028] With the above settings, the cumene raw material has acquired a large amount of heat energy before entering the preheater, which greatly reduces the steam or power consumption load of the preheater and realizes the efficient recovery and comprehensive utilization of energy inside the device. As a cooling medium, cumene also avoids the problem of scaling on the condenser tube 4 to a certain extent.

[0029] Example 2 Based on Example 1, this example further optimizes the internal structure of the condenser to enhance heat transfer efficiency.

[0030] The condenser tube 4 adopts a multi-tube design, including an inlet connector 41 and an outlet connector 43. Both the inlet connector 41 and the outlet connector 43 are hollow annular cylindrical structures. An inlet pipe 42 is welded to the inlet connector 41 for connecting the room-temperature cumene raw material; an outlet pipe 44 is welded to the outlet connector 43 for discharging the heated cumene raw material. Between the inlet connector 41 and the outlet connector 43, multiple metal heat exchange tubes 45 (such as stainless steel tubes) are connected in parallel, forming a compact tube bundle. After the cumene raw material enters the inner cavity of the inlet connector 41 through the inlet pipe 42, it is evenly distributed into each heat exchange tube 45, flows upward in parallel, and finally converges in the outlet connector 43 before flowing out through the outlet pipe 44.

[0031] The outer casing 1 is designed to accommodate the aforementioned tubing bundle. The outer casing 1 includes a central cylindrical body 11 and two connecting cylinders 12 connected to the upper and lower ends of the body 11 via flanges. The diameters of these two connecting cylinders 12 are significantly larger than the diameter of the central cylinder 11, thus providing ample space to accommodate the inlet connector 41 and the outlet connector 43. The inlet connector 41 is fixed inside the lower connecting cylinder 12, and the outlet connector 43 is fixed inside the upper connecting cylinder 12.

[0032] To significantly improve the condensation efficiency of gaseous crude acetone, a spiral guide 5 is added inside the central cylinder 11 in this embodiment. The spiral guide 5 can be a continuous spiral plate welded to the inner wall of the cylinder 11, or it can be segmented guide vanes, forming a spiral-shaped flow channel between itself and the inner wall of the cylinder 11. A tube bundle consisting of multiple heat exchange tubes 45 is inserted through the spiral guide 5.

[0033] During operation, high-temperature gaseous crude acetone enters the cylinder 11 tangentially or radially from the inlet pipe 3, located below the initial height of the spiral guide 5. Under the constraint and guidance of the spiral guide 5, the gaseous material is forced to change its original free-flow state, rotating and rising along the spiral channel. First, the spiral path significantly extends the flow path and residence time of the gaseous material within the condenser, allowing for more thorough heat exchange with the heat exchange tubes 45. Second, the centrifugal force generated by the rotating flow makes it easier for droplets in the gaseous phase to be thrown towards the tube and shell walls, promoting gas-liquid separation and the discharge of the condensate film. Most importantly, the intense spiral turbulence effectively disrupts the heat transfer boundary layer on the outer wall of the heat exchange tubes 45, significantly improving the convective heat transfer coefficient, thereby enhancing the overall heat exchange efficiency of the condenser.

[0034] The condensed liquid crude acetone falls along the shell wall under the action of gravity and eventually collects in the storage tank 2 at the bottom.

[0035] Example 3 This embodiment further refines the details based on Embodiment 2 to improve the reliability, maintainability, and final energy efficiency of the equipment.

[0036] The connection between the heat exchange tube 45 and the inlet connector 41 and outlet connector 43 must ensure sealing and pressure resistance. A connection hole is machined on the inlet connector 41 and outlet connector 43 corresponding to the position of each heat exchange tube 45. The end of the heat exchange tube 45 is sealed and installed in this connection hole by expansion or welding, thereby ensuring reliable communication between the inner cavity of the heat exchange tube 45 and the inner cavity of the connector, and enabling it to withstand the system operating pressure.

[0037] To further expand the heat transfer area and enhance the heat transfer between the media inside and outside the tube, multiple annular heat-conducting fins 7 are fixed to the outer wall of each heat exchange tube 45 by interference fit or welding. These heat-conducting fins 7 are arranged at intervals along the axial direction of the heat exchange tube 45, which can effectively break the flow boundary layer and significantly increase the contact area with the gaseous crude acetone.

[0038] Multiple heat exchange tubes 45 are arranged in parallel in a regular tube bundle to ensure uniform fluid distribution.

[0039] A perforated plate 6 with several large holes is fixed to the bottom of the connecting cylinder 12 located at the lower part of the outer shell 1. The perforated plate 6 is sealed to the inlet of the liquid storage tank 2 through a flange. The condensed crude acetone flows into the liquid storage tank 2 through the perforated plate 6. The perforated plate 6 does not affect the flow of liquid, but it significantly obstructs the airflow to prevent the airflow from disturbing the liquid in the liquid storage tank 2.

[0040] Obviously, those skilled in the art can make various modifications and variations to this utility model without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this utility model and their equivalents, this utility model also intends to include these modifications and variations.

Claims

1. A cascade heat exchange apparatus for preparing phenol and acetone, comprising an oxidizer, a preheater, a feed pump, and a condenser for cooling crude acetone in the gas phase, characterized in that, The condenser includes: The outer casing has an air outlet pipe at its top, a liquid storage tank at its bottom, and an air inlet pipe on its lower side wall. A condenser tube is installed inside the outer casing, with its inlet and outlet ends extending out of the casing; The feed pump delivers cumene raw material, which then passes through a condenser and a preheater before entering the oxidizer.

2. The cascade heat exchanger for preparing phenol and acetone as described in claim 1, characterized in that, The condenser includes: Liquid inlet connector, wherein a liquid inlet pipe is provided on the liquid inlet connector; A liquid outlet connector, wherein a liquid outlet pipe is provided on the liquid outlet connector; Multiple heat exchange tubes are connected between the inlet and outlet joints. After the cumene raw material enters the inlet joint through the inlet pipe, it flows through the multiple heat exchange tubes and is discharged from the outlet pipe of the outlet joint.

3. The cascade heat exchanger for preparing phenol and acetone as described in claim 2, characterized in that, The outer shell includes a cylindrical body and two connecting cylinders respectively disposed at the upper and lower ends of the cylindrical body. The diameter of the connecting cylinders is larger than the diameter of the cylindrical body. The liquid inlet connector and the liquid outlet connector are respectively disposed inside the two connecting cylinders.

4. The cascade heat exchanger for preparing phenol and acetone as described in claim 3, characterized in that, The cylinder is equipped with a spiral guide, which forms a flow channel with the inner wall of the cylinder for the spiral ascent of crude acetone in the gas phase.

5. A cascade heat exchanger for preparing phenol and acetone as described in claim 4, characterized in that, Multiple heat exchange tubes are inserted into the spiral guide member.

6. The cascade heat exchanger for preparing phenol and acetone as described in claim 4, characterized in that, The air intake pipe is located on the side wall of the cylinder below the spiral guide.

7. The cascade heat exchanger for preparing phenol and acetone as described in claim 3, characterized in that, The bottom of the lower connecting cylinder is provided with an orifice plate and is sealed to the liquid storage tank by a flange.

8. A cascade heat exchanger for preparing phenol and acetone as described in claim 2, characterized in that, The liquid inlet connector has multiple connection holes that communicate with the inner cavity of the liquid inlet connector; the end of the heat exchange tube is sealed and installed in the connection holes, so that the inner cavity of the heat exchange tube communicates with the inner cavity of the liquid inlet connector.

9. A cascade heat exchanger for preparing phenol and acetone as described in claim 2, characterized in that, Multiple heat-conducting plates are fixed on the heat exchange tube, and the heat-conducting plates are in the shape of a ring.

10. A cascade heat exchanger for preparing phenol and acetone as described in claim 2, characterized in that, The multiple heat exchange tubes are arranged in parallel in the form of a tube bundle.

Images