A plate heat exchanger for methanol plant

Abstract

This utility model proposes a plate-and-shell heat exchanger for a methanol plant, comprising a shell and a plate bundle assembly. The plate bundle assembly is supported inside the shell by a plate bundle support forging. The shell forms the shell-side medium path, and the plate bundle assembly forms the plate-side medium path. The plate bundle support forging is a component of the shell and is located in the diameter-changing section of the shell. It is equipped with a support platform inside the shell, on which a gasket is placed. Above the gasket is the tube sheet, and above the edge of the tube sheet is a clamping block. Above the clamping block is a clamping block stop seat, which is fixed to the inner wall of the shell. Beneficial effects: The tube sheet and the plate bundle support forging are flexibly connected by gaskets, achieving installation positioning and vibration buffering. A clamping device is provided on the upper side of the tube sheet to prevent shaking and displacement during transportation, demonstrating significant engineering versatility and life-cycle cost advantages.

Description

Technical Field

[0001] This utility model belongs to the field of heat exchangers and relates to the improvement of plate and shell heat exchangers. Background Technology

[0002] Traditional plate-and-shell heat exchangers are widely used in methanol plants for high-parameter applications such as syngas cooling and waste heat recovery. Their core design relies on efficient heat transfer through compact flow channels and the shell's pressure-bearing capacity to adapt to methanol synthesis conditions. However, as methanol processes move towards higher energy efficiency and lower emissions, existing technologies are gradually revealing limitations such as poor maintenance convenience, insufficient plate alignment and thermal stress control, and rigid overload of support and clamping structures.

[0003] Existing plate-and-shell heat exchangers only have top and bottom manholes in the shell, and the plate bundles are mostly closed, fully welded structures. There are no dedicated maintenance channels inside the plate bundles, requiring destructive disassembly for maintenance, resulting in long downtime and failing to meet the demands of continuous production. Furthermore, the lack of an active self-aligning mechanism at the tail of the plate bundles makes them prone to misalignment under high-temperature thermal expansion, leading to uneven flow distribution and exacerbating localized corrosion or scaling. The shell and tube sheet are connected by flange bolts, and thermal expansion compensation relies on expansion joints, which are prone to failure under high-pressure conditions. While existing plate-and-shell heat exchangers can meet basic requirements, the need for upgrading to high-efficiency methanol plants necessitates structural innovation to improve equipment reliability, maintainability, and adaptability to different operating conditions. Utility Model Content

[0004] The purpose of this invention is to propose a plate-and-shell heat exchanger for methanol plants to address the aforementioned technical shortcomings.

[0005] The technical solution of this utility model is as follows: A plate-and-shell heat exchanger for a methanol plant includes a shell and a plate bundle assembly. The plate bundle assembly is supported inside the shell by a plate bundle support forging. The shell forms the shell-side medium path, and the plate bundle assembly forms the plate-side medium path. The plate bundle support forging is a component of the shell and is located in the diameter-changing section of the shell. It is provided with a support platform inside the shell. A gasket is placed on the support platform, and a tube sheet is placed on top of the gasket. A clamping block is provided above the edge of the tube sheet, and a clamping block stop is above the clamping block. The clamping block stop is fixed to the inner wall of the shell. The tube sheet and the plate bundle support forging are flexibly connected by the gasket. The outer edge shape of the clamping block is adapted to the inner wall shape of the plate bundle support forging.

[0006] Furthermore, the lower end of the tube box at the tail of the plate bundle is equipped with a self-aligning and positioning mechanism, which includes an arc-shaped support plate, an intermediate connecting block, and an adjusting nut. There are four arc-shaped support plates, which are symmetrically distributed radially. The arc-shaped edges of the arc-shaped support plates are fixedly connected to the shell. The corners of the arc-shaped support plates are concave. A connecting block is fixed on the upper or lower surface of the concave edge, and a screw hole is provided on the connecting block. The intermediate connecting block is provided with a threaded hole connecting seat. The threaded hole connecting seat is connected to the connecting block by bolts. Adjusting nuts are provided on both sides or one side of the connecting block. The adjusting nuts are located on the bolts. The end face of the intermediate connecting block is fixedly connected to the outer wall of the lower end tube box. When self-alignment is completed, the adjusting nuts tighten the bolts, connecting blocks, and threaded hole connecting seats.

[0007] The upper and lower ends of the plate bundle assembly are respectively connected to the upper tube box and the lower tube box. The upper part of the upper tube box is connected to the upper expansion joint, and the upper part of the upper expansion joint is connected to the plate side medium outlet pipe. The lower part of the lower tube box is connected to the lower expansion joint, and the lower part of the lower expansion joint is connected to the plate side medium inlet pipe. The upper and lower expansion joints adopt a multi-layer corrugated structure. The upper part of the shell is provided with the shell side medium inlet pipe, and the lower part of the shell is provided with the shell side medium outlet pipe.

[0008] The upper pipe box is provided with a plate bundle maintenance manhole, the upper part of the shell is provided with an upper manhole, and the lower part of the shell is provided with a lower manhole.

[0009] The end face of the intermediate connecting block is inclined, and it fits into the slope of the outer wall of the lower pipe box.

[0010] The beneficial effects of this utility model are as follows: 1. The tube sheet and the plate bundle support forging are flexibly connected by high-pressure resistant gaskets, achieving installation positioning and vibration buffering. A clamping device is also provided on the upper side of the tube sheet to prevent shaking and displacement during transportation, which has significant engineering applicability and cost advantages throughout the entire life cycle.

[0011] 2. Applied to methanol plant applications, it solves the core requirements of methanol plants for high pressure, high corrosion, and long-term operation.

[0012] 3. A maintenance manhole is provided on the side wall of the upper end of the plate bundle tube box to avoid the protruding structure occupying external space of the equipment and to adapt to the layout of compact methanol plants. This design breaks through the traditional "whole disassembly" maintenance mode of plate and shell heat exchangers, realizes online maintenance of key heat transfer elements, and ensures the continuous production needs of methanol plants.

[0013] 4. A detachable self-aligning positioning mechanism is added to the tail of the plate bundle, significantly optimizing structural stability and flow field uniformity under high-temperature conditions. It provides vibration-resistant rigid support during transportation, reducing the risk of structural damage. During installation, self-alignment is achieved by adjusting the bolt screw-in length to change the contact tightness between the end face of the intermediate connecting block and the lower pipe box. This self-aligned plate bundle ensures uniform free expansion and contraction along a preset path under high-temperature thermal expansion, avoiding uneven medium distribution caused by flow channel deviation and suppressing crystallization and scaling due to dead zones. After the equipment is installed in place, the bolts are removed, retaining the arc-shaped support plate as a flexible guiding structure to avoid thermal stress concentration caused by rigid constraints. Attached Figure Description

[0014] Figure 1 —Schematic diagram of plate and shell heat exchanger equipment for methanol plant; Figure 2 —Schematic diagram of the centering and positioning mechanism; Figure 3 — Schematic diagram of plate bundle support forging and clamping structure. Detailed Implementation

[0015] like Figure 1 , 3 A plate-and-shell heat exchanger for a methanol plant includes core components such as a shell 8, a plate bundle assembly 7, a plate bundle support forging 15, an expansion joint, and a medium connection pipe. The plate bundle assembly 7 is composed of multiple sets of corrugated plates stacked together, welded at both ends to an upper tube box 17 and a lower tube box 12, forming a closed heat transfer unit. The alternating flow channels between the corrugated plates constitute the plate side and shell side medium channels, respectively. The plate bundle support forging 15 is part of the shell 8, located in the shell's variable diameter section, and has a support platform inside the shell 8. A gasket 5 is placed on the support platform, and a tube sheet 6 is placed above the gasket 5. A clamping block 18 is located above the edge of the tube sheet 6, and a clamping block stop 181 is located above the clamping block 18. The clamping block stop 181 is fixed to the inner wall of the shell 8. The tube sheet 6 and the plate bundle support forging 15 are flexibly connected by the gasket 5, achieving installation positioning and vibration buffering. The outer edge shape of the clamping block 18 is adapted to the inner wall shape of the plate bundle support forging 15. The clamping block 18 presses the tube sheet 6 to prevent it from shaking during transportation.

[0016] The plate bundle assembly 7 is connected to the upper tube box 17 and the lower tube box 12 at its upper and lower ends, respectively. The upper tube box 17 is connected to the upper expansion joint 2, and the upper part of the upper expansion joint 2 is connected to the plate-side medium outlet pipe 1. The lower tube box 12 is connected to the lower expansion joint 10, and the lower part of the lower expansion joint 10 is connected to the plate-side medium inlet pipe 11. The plate-side medium inlet and outlet pipes are integrated on the outside of the upper and lower expansion joints and are directly connected to the internal flow channel of the tube box. The upper expansion joint 2 and the lower expansion joint 10 adopt a multi-layer corrugated structure, which can effectively compensate for the axial thermal expansion difference between the plate bundle and the shell. The shell-side medium inlet pipe 16 is welded to the upper part of the shell 8, and the shell-side medium outlet pipe 9 is welded to the lower part of the shell 8. The shell-side medium inlet and outlet pipes are connected to the shell-side flow channel.

[0017] The upper end of the tube box is connected to the plate bundle maintenance manhole 4, which is sealed with a manhole flange cover and a metal spiral wound gasket. During maintenance, the plate bundle can be partially cleared or replaced through the plate bundle maintenance manhole 4 without disassembling the entire plate bundle structure. The shell side wall is also provided with an upper manhole 3 and a lower manhole 14 to ensure unobstructed access for the maintenance of internal components.

[0018] A self-aligning positioning mechanism 13 is provided at the tail of the plate bundle (see Figure 2 The assembly consists of an arc-shaped support plate 131, an intermediate connecting block 132, and adjusting nuts 133. There are four arc-shaped support plates 131, symmetrically distributed radially. The arc-shaped edges of the support plates 131 are fixedly connected to the housing 8. The corners of the arc-shaped support plates 131 are concave, and a connecting block 136 is fixed to the lower surface of the concave edge. A screw hole is provided in the connecting block 136. The intermediate connecting block 132 is provided with a threaded hole connecting seat 134. The threaded hole connecting seat 134 is connected to the connecting block 136 by bolts 135. Adjusting nuts 133 are provided on both sides or one side of the connecting block 136, and are mounted on the bolts 135. The end face of the intermediate connecting block 132 is welded to the outer wall of the lower end housing 12. When the alignment is complete, the adjusting nuts 133 tighten the bolts to the connecting block 136 and the threaded hole connecting seat 134. The distance between the intermediate connecting block and the connecting block 136 is changed by rotating the housing to adjust the screw-in length of the bolts on the unstressed side, so that the various surfaces of the lower tube box 12 are basically evenly stressed, achieving self-alignment. After self-alignment is completed, the adjusting nut 133 is tightened. After the equipment is installed in place on site, the adjusting nut 133 and bolt 135 are removed to allow the plate bundle to expand freely. In addition, during transportation, the self-aligning positioning mechanism provides rigid temporary support for the tail of the plate bundle, effectively resisting vibration and impact; during operation, it switches to an unconstrained state, taking into account both installation accuracy and thermal compensation requirements.

Claims

1. A plate heat exchanger for methanol plants, comprising a shell (8) and a plate pack assembly (7) supported inside the shell (8) by a plate pack support forging (15), the shell (8) forming a shell-side medium path and the plate pack assembly (7) forming a plate-side medium path, characterized in that: The plate bundle support forging (15) is a component of the shell (8) and is located in the diameter-changing section of the shell. It is provided with a support platform inside the shell (8). A gasket (5) is placed on the support platform. A tube sheet (6) is above the gasket (5). A clamping block (18) is provided above the edge of the tube sheet (6). A clamping block stop (181) is above the clamping block (18). The clamping block stop (181) is fixed to the inner wall of the shell (8). The tube sheet (6) and the plate bundle support forging (15) are flexibly connected by the gasket (5). The outer edge shape of the clamping block (18) is adapted to the inner wall shape of the plate bundle support forging (15).

2. A plate heat exchanger for methanol plants according to claim 1, characterized in that: The lower end tube box (12) at the tail of the plate bundle is provided with a self-aligning positioning mechanism (13), which includes an arc-shaped support plate (131), an intermediate connecting block (132), and an adjusting nut (133). There are four arc-shaped support plates (131) distributed radially symmetrically. The arc-shaped edge of the arc-shaped support plate (131) is fixedly connected to the shell (8). The corner of the arc-shaped support plate (131) is concave. A connecting block (136) is fixed on the upper or lower surface of the concave edge, and a screw hole is provided in the connecting block (136). The connecting block (132) is provided with a threaded hole connecting seat (134). The threaded hole connecting seat (134) is connected to the connecting block (136) by bolts (135). The connecting block (136) is provided with adjusting nuts (133) on both sides or one side. The adjusting nuts (133) are located on the bolts (135). The end face of the middle connecting block (132) is fixedly connected to the outer wall of the lower end pipe box (12). When the self-alignment is completed, the adjusting nuts (133) tighten the bolts to the connecting block (136) and the threaded hole connecting seat (134).

3. A plate heat exchanger for methanol plants according to claim 1, characterized in that: The upper and lower ends of the plate bundle assembly (7) are respectively connected to the upper end pipe box (17) and the lower end pipe box (12). The upper end pipe box (17) is connected to the upper end expansion joint (2). The upper end expansion joint (2) is connected to the plate medium outlet pipe (1). The lower end pipe box (12) is connected to the lower end expansion joint (10). The lower end expansion joint (10) is connected to the plate medium inlet pipe (11). The upper end expansion joint (2) and the lower end expansion joint (10) adopt a multi-layer corrugated structure. The upper part of the shell (8) is provided with the shell medium inlet pipe (16), and the lower part of the shell (8) is provided with the shell medium outlet pipe (9).

4. A plate heat exchanger for methanol plants according to claim 3, characterized in that: The upper pipe box (17) is provided with a plate bundle maintenance manhole (4), the upper part of the shell (8) is provided with an upper manhole (3), and the lower part of the shell (8) is provided with a lower manhole (14).

5. A plate heat exchanger for methanol plants according to claim 2, characterized in that: The end face of the intermediate connecting block (132) is a bevel, which is adapted to fit the bevel of the outer wall of the lower pipe box (12).

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