CN1140764C - Scaling tube full counterflow double shell side axial flow heat exchanger and its heat transfer method - Google Patents

Abstract

The invention relates to a full-counter-current double-shell-side axial flow heat exchanger with zoom tubes and a heat exchange method thereof. The heat exchanger is mainly composed of a shell, a partition, a zoom heat transfer tube, a grid-type tube support, a tube plate at both ends, a head cover at both ends, a shell side and a tube side inlet and outlet tubes. As an enhanced heat transfer tube, the grille is used as the support between the tubes, and the shell is divided into double shells by the longitudinal partition. The plates form double-shell side shaft up-and-coming flow passages, and the double-shell side full-counterflow axial flow heat exchanger is formed through the tube sheets at both ends and the head cover. The invention has the advantages and effects of high heat transfer temperature difference utilization rate, small flow resistance, low operating energy consumption, good heat transfer enhancement performance, less equipment material consumption, less investment, and compact volume.

Description

Scaling tube full counterflow double shell side axial flow heat exchanger and its heat transfer method

The invention relates to a full-counter-flow double-shell-side axial-flow heat exchanger with zoom tubes and a heat exchange method thereof, which belongs to heat transfer enhancement technical equipment, and particularly relates to shell-and-tube heat exchange equipment.

There are many shell-side structures of shell-and-tube heat exchangers. In industry, shell-and-tube heat exchangers with bow-shaped baffles supporting tube bundles are commonly used. The fluid moves back and forth between the baffle partitions, and there are also shell-and-tube heat exchangers with grid plates supporting tube bundles. The Chinese patent number is: ZL93243442.8 and shell-and-tube heat exchangers with hollow rings supporting tube bundles. The Chinese patent number is : 89218385.3, the shell-side fluid of the latter two heat exchangers is axial flow, referred to as the shell-side axial flow shell-and-tube heat exchanger. When the volume flow rate of the hot and cold streams is not large, but the temperature rise and drop are large, and the heat transfer temperature difference between the cold and hot sides is small, the above-mentioned heat exchangers have the following different defects, (1) the baffle plate The heat transfer temperature difference utilization rate of the shell-and-tube heat exchanger is low, and it is often difficult to complete the heat transfer task in a single-shell or even a double-shell; (2) The ordinary shell-side axial flow shell-and-tube heat exchanger is mostly a single-shell structure , and most of the heat transfer tubes are smooth tubes, so when the material flow on both sides of the tube shell is not large, to obtain an appropriate flow rate, the shell diameter will be small, and the length-to-diameter ratio of the heat exchanger is too large, which cannot be installed in industrial systems . Due to the above reasons, in the industry, multiple shell-and-tube heat exchangers with baffle plates are often connected in series to complete the heat exchange task. The equipment investment is high, the floor area is large, and the loss of fluid resistance is large.

The purpose of the present invention is to solve and overcome the low effective utilization rate of the heat transfer temperature difference of the existing heat exchanger under the above-mentioned special working conditions, it is difficult to complete the heat transfer task, and it is required to use multiple heat exchangers to operate in series, resulting in the heat exchanger The problems and shortcomings of large fluid resistance loss, high operating energy consumption, large equipment investment, or too large aspect ratio of the shell, which cannot be installed in industrial systems, have been researched and invented. One or two heat exchangers run, the fluid resistance of the heat exchanger is small, the operation energy consumption is low, the equipment investment is low, and the zoom tube full countercurrent double shell side axial flow heat exchanger and its heat exchange are easy to implement in the industrial system. method.

The present invention is realized through the following technical solutions. The schematic diagram of the structure of the full-counterflow double-shell side axial flow heat exchanger with zoom tubes is shown in Figure 1, and its A-A view is shown in Figure 2, and the zoom tube is shown in Figure 3. As shown in Figure 4-5, the grille-type tube support is shown in Figure 4-5. The heat exchanger is divided into two processes in the longitudinal direction by the longitudinal partition plate in the diameter, and the shell side fluid flow channel is formed by the heat transfer tube The outer wall of the shell, the inner wall of the shell, the longitudinal partition and the tube sheets at both ends constitute the double-shell side axial reciprocating flow channel; it mainly consists of the heat exchanger shell 1, the longitudinal partition 2, and the zoom-type heat transfer tube 3 , grid plate type inter-tube supports 4, tube sheets 5 at both ends, sealing covers 6 at both ends, shell-side inlet and outlet pipes 7, 8 and tube-side inlet and outlet pipes 9, 10 are jointly connected to form, and their mutual positions and connection relations are: In the heat exchanger shell 1, a plurality of scaling heat transfer tubes 3 are evenly distributed in the axial direction, and are welded or expanded with the tube sheets 5 at both ends of the shell 1, and the longitudinal partition 2 is close to the shell-side inlet and outlet pipes 7 , 8 The tube sheet at one end is sealed and connected with the inner wall of the shell attached to the diameter of the tube sheet, dividing the shell into two passes, and the longitudinal partition 2 has a gap at the junction with the tube sheet at the other end, forming The return path of the shell-side flow channel, the head caps 6 at both ends are connected with the tube plates 5 at both ends to form the return flow route of the tube-side flow channel and the inlet and outlet pipes 9, 10, and the grid-type inter-tube supports 4 are arranged equidistantly between the tube bundles in the axial direction And it is connected with the scaling heat transfer tube 3 to become the inter-tube support of the heat transfer tube. The grid-type inter-tube support is divided into two types: longitudinal grid and horizontal grid. Realize the horizontal and vertical positioning of the heat transfer tubes and prevent the vibration of the tube bundle; among them: the scaling heat transfer tube 3 is composed of repeated and continuous shrinkage and expansion tube sections, the thickness of the tube wall is uniform, the scaling waveforms on both sides of the tube are symmetrical, and the grid plate type The intertube support consists of slats with a width greater than one rib pitch on the scaled tube.

The heat exchange method of this heat exchanger: the shell-side fluid flows along the inlet and the inlet shell 1, flows along the axial flow channel, deflects back at the gap at the tail of the longitudinal partition 2, then flows along the axial flow channel, and then flows from the The outlet 8 flows out of the shell, and the tube side fluid enters the head cover 6 along the inlet 9, and enters the tube side from the tube plate 5, and flows in the reverse axial flow with the shell side fluid, and turns back at the other head cover to form a double tube pass Axial flow, and then flow out of the tube side from the outlet 10, the tube side and the shell side fluid perform full countercurrent flow heat exchange during the heat exchange process; the key is to use a zoom tube with symmetrical concave and convex ribs on both sides of the tube, The fluid enhances heat transfer at the same time, and through the double-shell side structure, the fluid on both sides of the shell can obtain a more appropriate flow rate when the volume flow rate is not high, so that the heat exchanger can also obtain a higher total heat transfer under the condition of full counterflow coefficient, and the heat transfer temperature difference utilization rate of the heat exchanger can reach 100%. The grid plate is used as the support between the tubes of the scaling tube bundle, the fluid resistance is small, and the shell side pressure is reduced.

Compared with the prior art, the present invention has the following advantages and beneficial effects: (1) The heat exchanger is a full-counterflow heat exchanger composed of an enhanced scaling heat transfer tube bundle and a double-shell heat exchanger structure. The tube-side and shell-side fluids in the device are fully countercurrent heat exchange during the heat exchange process, and the utilization rate of the heat transfer temperature difference reaches 100%, avoiding the shortcoming of the cross-flow heat transfer in the prior art that the effective heat transfer temperature difference is small; while maintaining a high (2) Due to the small loss of fluid resistance to the fluid resistance of the supports between grid plate tubes, the pressure on the shell side of the heat exchanger is reduced, and the power consumption required for fluid transportation is small, so the shell side of the heat exchanger The axial flow structure has the advantages of small fluid resistance loss and low energy consumption during operation, which avoids the high resistance loss caused by the baffle partition in the prior art, and can greatly save operating energy consumption; (3) The heat exchanger adopts scaling As a heat transfer tube, the tube can obtain a good heat transfer enhancement effect under the condition of low flow rate, which helps to shorten the length of the heat transfer tube and avoid the shortcoming of the tube being too long when using a smooth tube. In industrial systems (4) Due to the use of high-efficiency heat transfer tubes and double-shell side axial flow full countercurrent heat exchange, the heat transfer performance of the heat exchanger is greatly improved, especially under turbulent flow conditions (Re number > 5000), using Scalable heat transfer tubes with symmetrical concave and convex rib surfaces on both sides of the inner and outer sides of the tube. The fluid flowing longitudinally on both sides of the inner and outer sides of the tube is used for enhanced convective heat transfer, which can obtain a good heat transfer enhancement effect on both sides, and the heat transfer film coefficient of the fluid on both sides is higher; it can be greatly improved. The required heat exchange area can be reduced, and the investment of heat exchange equipment in the prior art can be greatly reduced. At the same time, the utility model has a compact volume and is convenient for installation and maintenance of the equipment.

The accompanying drawings of the specification are further described as follows: Fig. 1 is a schematic structural view of a full-counterflow double-shell axial flow heat exchanger with zoom tubes; Fig. 2 is a view from the direction A-A of Fig. 1; Fig. 3 is a schematic diagram of zoom tubes; Fig. 4, Fig. 5 is a schematic diagram of grid-plate inter-tube supports.

The embodiment of the present invention is relatively simple, and stainless steel or carbon steel can be used as the material, and it can be processed by using ordinary sheet metal technology, machining methods and equipment. To implement the present invention, as long as each part of the device is designed and processed as shown in Figures 1 to 5, and connected and assembled according to the interconnection relationship described in the above specification to form the flow channel structure shown in Figure 1, it can be implemented better this invention. For example, the inventor recommends to design a shell of φ500×6×6000mmmm, divide the shell into two passes along the axial direction with a longitudinal partition of 488×5750mm, and distribute 300 scaling tubes of φ19×2×6000mm evenly in each pass. Arranged in a square, connected to the φ560×20mm tube plates at both ends, and the grid plate support is used to support and position the tubes to prevent the tube bundle from vibrating. The tube plates at both ends are sealed with φ500×500mm head caps.

Claims (3)

1, a kind of convergent-divergent tube, full counterflow bivalve journey axial flow-type heat exchanger, it is characterized in that: this heat exchanger longitudinally is divided into double-current journey with heat exchanger shell by longitudinal baffle on diameter, the shell-side fluid runner is the outer wall by heat-transfer pipe, the inwall of housing, the bivalve journey that longitudinal baffle and two ends tube sheet constitute axially come and go runner; It is mainly by heat exchanger shell (1), longitudinal baffle (2), scaling type heat-transfer pipe (3), support (4) between screen formula pipe, two ends tube sheet (5), sealing two ends lid (6), shell side is imported and exported pipe (7), (8) and tube side import and export pipe (9), (10) connect and compose jointly, its mutual alignment and annexation are: in heat exchanger shell (1), many convergent-divergent heat-transfer pipes (3) are uniform vertically, and weld mutually or expanded joint with housing (1) two ends tube sheets (5), longitudinal baffle (2) is imported and exported pipe (7) near shell side, the tube sheet of (8) one ends, and the inner walls of pasting mutually at the diameter place of tube sheet is tightly connected, housing is divided into two journeys, and longitudinal baffle (2) is having one section breach with other end tube sheet junction stream, constitute the return flow path of shell side runner, two ends end socket lids (6) are connected to form the backflow route of tube side runner and import and export pipe (9) with two ends tube sheet (5), (10), support (4) equidistantly is placed in interbank vertically and is connected with convergent-divergent heat-transfer pipe (3) between screen formula pipe becomes support between the pipe of heat-transfer pipe, support is divided into vertical grid and two kinds of horizontal grid between screen formula pipe, when shell side is axially settled with two kinds of screens alternate lay with realize to heat-transfer pipe laterally and longitudinal register, prevent tube bundle vibration.

2,, it is characterized in that described convergent-divergent pipe heat-transfer pipe (3) is by repeating to constitute the pipe thickness uniformity with continuous contraction and expansion pipeline section by the described a kind of convergent-divergent tube, full counterflow of claim 1 bivalve journey axial flow-type heat exchanger.

3, by the described a kind of convergent-divergent tube, full counterflow of claim 1 bivalve journey axial flow-type heat exchanger, its feature is also between described screen formula pipe that support is is that convergent-divergent Guan Shangyi the lath more than the rib spacing constitutes by width.

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