New fire tube type high-pressure waste heat boiler

Abstract

Disclosed in the present utility model is a new fire tube type high-pressure waste heat boiler, comprising: a front-end tube box, a high-temperature section shell pass cylinder, a middle tube box, a low-temperature section shell pass cylinder and a rear-end tube box, which are connected in sequence; a high-temperature section heat exchange tube bundle arranged in the high-temperature section shell pass cylinder; a low-temperature section heat exchange tube bundle arranged in the low-temperature section shell pass cylinder; and a center tube, the inner center of which penetrates from the front-end tube box to the rear-end tube box and directly communicates the front-end tube box with the rear-end tube box, wherein the front-end tube box is sequentially in communication with the high-temperature section heat exchange tube bundle, the middle tube box, the low-temperature section heat exchange tube bundle and the rear-end tube box; flexible tube plates are provided at two ends of the high-temperature section shell pass cylinder and two ends of the low-temperature section shell pass cylinder; and a reinforcing rib is provided at a front portion in the high-temperature section shell pass cylinder, and the reinforcing rib is connected to the flexible tube plates. The fire tube type high-pressure waste heat boiler in the present utility model uses a two-section structure, and is also provided with the reinforcing rib and the flexible tube plates, such that the problem of strength failure of the tube plates and tube heads under high-temperature and high-pressure working conditions can be effectively solved, and the problem of excessive structural stress brought about by the up-scaling of devices and apparatuses can also be effectively solved.

Description

A new type of fire tube high pressure waste heat boiler Technical Field

[0001] The utility model belongs to the field of chemical equipment, and in particular relates to a novel fire tube type high-pressure waste heat boiler. Background Art

[0002] In methanol and synthetic ammonia production plants using natural gas, the reformed gas from the reformer reaches temperatures of 800-1200°C and pressures of around 4 MPa. Due to process requirements, the reformed gas needs to be cooled and its waste heat recovered to produce high-quality steam, which is used to power subsequent turbine units.

[0003] As equipment becomes increasingly larger, so too do the dimensions of the equipment. Existing waste heat boiler structures struggle to meet process performance requirements. Due to the high temperature and pressure of the reformed gas, waste heat boilers using traditional thick tubesheet structures can lead to high tubesheet stress and the risk of cracking in the tubehead welds.

[0004] Currently, the commonly used flexible tube sheet waste heat boiler is only suitable for moderate-sized installations and favorable operating conditions. Large installations can lead to significant temperature differential stress between the heat exchange tubes and the tube sheet, and conventional flexible tube sheet structures are unable to reduce this stress to a safe level. Furthermore, when the installation experiences load fluctuations, the medium temperature at the waste heat boiler outlet also fluctuates significantly, posing significant safety risks to the operation of subsequent equipment.

[0005] Utility Model Content

[0006] The purpose of the utility model is to address the defects of the existing technology and provide a two-stage reinforced rib flexible tube sheet waste heat boiler that can operate stably under high temperature and high pressure conditions, and at the same time has the function of adjusting the outlet medium temperature, which can adapt to the needs of large-scale devices and equipment.

[0007] To achieve the above-mentioned objectives, the present invention adopts the following technical solutions: a novel fire-tube high-pressure waste heat boiler, comprising: a front-end pipe box, a high-temperature shell-side cylinder, an intermediate pipe box, a low-temperature shell-side cylinder, and a rear-end pipe box connected in sequence; a high-temperature heat exchange tube bundle disposed in the high-temperature shell-side cylinder; a low-temperature heat exchange tube bundle disposed in the low-temperature shell-side cylinder; and a central pipe extending from the front-end pipe box to the rear-end pipe box and directly connecting the front-end and rear-end pipe boxes;

[0008] The front-end pipe box is connected in sequence to the high-temperature section heat exchange tube bundle, the middle pipe box, the low-temperature section heat exchange tube bundle and the rear-end pipe box;

[0009] Both ends of the high-temperature section shell-side cylinder and the low-temperature section shell-side cylinder are flexible tube sheets. Reinforcement ribs are provided in the front of the high-temperature section shell-side cylinder, and the reinforcement ribs are connected to the flexible tube sheets.

[0010] Furthermore, a gas inlet is provided on the side of the front end pipe box, and a gas distributor is provided below the gas inlet.

[0011] Furthermore, a gas outlet is provided at the end of the rear end pipe box.

[0012] Furthermore, a liquid inlet and an outlet are provided on the shell side of the high temperature section shell side cylinder and the low temperature section shell side cylinder.

[0013] Furthermore, the front end of the central tube is welded to the flexible tube plate at the front end of the high-temperature section shell cylinder, an expansion joint is provided at the middle pipe box, and a regulating valve is provided at the rear end of the rear end pipe box.

[0014] Furthermore, the reinforcing ribs are welded inside the high-temperature section shell cylinder and connected to the flexible tube sheet by welding.

[0015] Furthermore, the front end tube box, flexible tube sheet, high temperature section shell and barrel, and high temperature section heat exchange tube bundle are connected by welding, and the rear end tube box, tube sheet, low temperature section shell and barrel, and low temperature section heat exchange tube bundle are connected by welding.

[0016] This utility model features a novel fire-tube high-pressure waste heat boiler with a two-stage structure and a reinforced flexible tube sheet. This effectively addresses the issue of tube sheet and tube head strength failure under high-temperature and high-pressure conditions, as well as the excessive structural stress associated with large-scale equipment. Furthermore, a central tube is installed on the flexible tube sheet, with a regulating valve at the end to adjust the flow of high-temperature medium into the rear-end pipe box, thereby regulating the medium temperature at the waste heat boiler outlet. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG1 is a schematic structural diagram of a novel fire tube waste heat boiler device according to an embodiment.

[0018] FIG2 is a schematic diagram showing the connection between the reinforcing ribs and the flexible tube sheet according to an embodiment. DETAILED DESCRIPTION

[0019] In order to enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this application.

[0020] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or are inherent to these processes, methods, products or apparatuses.

[0021] As shown in Figure 1, the new fire-tube high-pressure waste heat boiler consists of a front-end pipe box 1, a gas distributor 2, a flexible tube sheet 3, a high-temperature section heat exchange tube bundle 4, a high-temperature section shell-side cylinder 5, an intermediate pipe box 6, a center pipe 7, an expansion joint 8, a low-temperature section heat exchange tube bundle 9, a low-temperature section shell-side cylinder 10, a regulating valve 11, a rear-end pipe box 12, and reinforcement ribs 13.

[0022] The front-end tube box 1, flexible tube sheet 3, high-temperature shell-side cylinder 5, and high-temperature heat exchange tube bundle 4 are connected by welding, and the reinforcing ribs 13 are welded to the flexible tube sheet 3. The rear-end tube box 12, tube sheet 3, low-temperature shell-side cylinder 10, and low-temperature heat exchange tube bundle 9 are connected by welding. In the front-end tube box 1, the gas inlet is arranged radially, and a gas distributor 2 is provided at the inlet to ensure the uniformity of the gas entering each heat exchange tube. The central tube 7 runs from the front-end tube box 1 to the rear-end tube box 12 and is welded to the flexible tube sheet 3 respectively. An expansion joint 8 is provided at the intermediate tube box to reduce the temperature difference stress of the central tube. At the same time, a regulating valve 11 is provided at the end of the central tube of the rear-end tube box to adjust the flow of high-temperature gas passing through the central tube from the front-end tube box to achieve the purpose of regulating the temperature of the gas medium in the rear-end tube box.

[0023] The new fire-tube high-pressure waste heat boiler adopts a two-stage design: the first section is the high-temperature heat exchange section, consisting of the high-temperature heat exchange tube bundle 4 and the high-temperature shell-side cylinder 5; the second section is the low-temperature heat exchange section, consisting of the low-temperature heat exchange tube bundle 9 and the high-temperature shell-side cylinder 10. The high-temperature reformed gas is evenly distributed through the front-end pipe box 1 and gas distributor 2 before entering the high-temperature heat exchange tube bundle 4, heating the water inside the high-temperature shell-side cylinder 5, causing it to boil and produce high-pressure saturated steam. After the high-temperature reformed gas is cooled by heat exchange in the first section, it enters the low-temperature heat exchange tube bundle 9 through the intermediate pipe box 6, heating the water inside the low-temperature shell-side cylinder 10 and producing high-pressure saturated steam. The reformed gas finally exits the rear-end pipe box 12 and enters the next process step.

[0024] The central tube 7 passes through the front-end tube box 1, the high-temperature shell-side cylinder 5, the intermediate tube box 6, and the low-temperature shell-side cylinder 10, reaching the rear-end tube box 12. A portion of the high-temperature reformed gas can flow directly from the central tube 7 to the rear-end tube box 12, where it mixes with the reformed gas after heat exchange. The temperature of the final mixed reformed gas is adjusted by regulating the flow rate of the high-temperature reformed gas in the central tube 7 using a regulating valve 11. An expansion joint 8 is installed in the intermediate tube box 6 to absorb thermal expansion differences within the central tube, ensuring the safety and reliability of the central tube 7.

[0025] As shown in FIG2 , the reinforcing ribs 13 are welded to the high-temperature section tube sheet 3 and simultaneously to the high-temperature section cylinder 10 , effectively strengthening the flexible tube sheet and reducing the tube sheet stress, which is a key technology for achieving large-scale devices and equipment.

[0026] The above is a further detailed description of the present invention and should not be considered as a limitation on the specific implementation of the present invention. For those skilled in the art of the present invention, simple deductions or substitutions that do not depart from the concept of the present invention are within the scope of protection of the present invention.

Claims

1. A new type of fire tube high pressure waste heat boiler, characterized in that include: The front pipe box, high temperature section shell cylinder, intermediate pipe box, low temperature section shell cylinder and rear pipe box connected in sequence, the high temperature section heat exchange tube bundle arranged in the high temperature section shell cylinder, the low temperature section heat exchange tube bundle arranged in the low temperature section shell cylinder, and the central pipe running from the front pipe box to the rear pipe box and directly connecting the front and rear pipe boxes; The front-end pipe box is connected in sequence to the high-temperature section heat exchange tube bundle, the middle pipe box, the low-temperature section heat exchange tube bundle and the rear-end pipe box; Both ends of the high temperature section shell cylinder and the low temperature section shell cylinder are flexible tube sheets, and reinforcing ribs are arranged at the front of the high temperature section shell cylinder, and the reinforcing ribs are connected to the flexible tube sheets.

2. The novel fire tube high pressure waste heat boiler according to claim 1 is characterized in that: The front end pipe box is provided with a gas inlet at the side, and a gas distributor is provided below the gas inlet.

3. The novel fire tube high pressure waste heat boiler according to claim 1 is characterized in that: A gas outlet is provided at the end of the rear end pipe box.

4. The novel fire tube high pressure waste heat boiler according to claim 1 is characterized in that: The shell sides of the high-temperature section shell side cylinder and the low-temperature section shell side cylinder are both provided with a liquid inlet and an outlet.

5. The novel fire tube high pressure waste heat boiler according to claim 1 is characterized in that: The front end of the central tube is welded to the flexible tube plate at the front end of the high temperature section shell cylinder, an expansion joint is arranged at the middle tube box, and a regulating valve is arranged at the rear end of the rear end tube box.

6. The novel fire tube high pressure waste heat boiler according to claim 1 is characterized in that: The reinforcing ribs are welded inside the high temperature section shell cylinder and connected to the flexible tube sheet by welding.

7. The novel fire tube high pressure waste heat boiler according to claim 1 is characterized in that: The front end tube box, flexible tube sheet, high temperature section shell cylinder, and high temperature section heat exchange tube bundle are connected by welding, and the rear end tube box, tube sheet, low temperature section shell cylinder, and low temperature section heat exchange tube bundle are connected by welding.

Images