Sulfuric acid preheater used in low-temperature waste heat recovery system

Abstract

The utility model relates to the technical field of heat exchangers, in particular to a sulfuric acid preheater used in a low-temperature waste heat recovery system, which comprises a plurality of shells, end sockets, tube plates, silicon carbide heat exchange tube bundles and baffle plates, the two ends of each shell in the length direction are respectively provided with a shell connector, each end socket is provided with an end socket connector, and the shell connectors are connected with the silicon carbide heat exchange tube bundles. The shells are connected end to end, two tube plates are clamped between every two connected shells, the outer ends of the two shells located at the ends are connected with end sockets, tube plates are clamped between the end sockets and the shells, and tube plate holes are formed in the tube plates; the two oppositely-arranged tube plates are provided with silicon carbide heat exchange tube bundles in a sealed mode through tube plate holes, the silicon carbide heat exchange tube bundles in the shells communicate with each other, connectors of every two adjacent shells are connected through a pipeline, baffle plates are arranged in each shell in a staggered mode, the baffle plates are arranged in a bent mode towards one end socket, and the baffle plates are arranged in a staggered mode towards the other end socket. Materials are taken, the design is reasonable, and the service life can be effectively prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of heat exchangers, in particular to a sulfuric acid preheater used in a low-temperature waste heat recovery system. Background Art

[0002] The sulfuric acid industry has developed to the point where its production process and technology have matured and improved. The sulfuric acid production process is that the sulfur raw material is oxidized into sulfur dioxide, then catalytically oxidized into sulfur trioxide, and then absorbed by water to become sulfuric acid. These three steps are all exothermic reactions. Usually, they are divided into high temperature, medium temperature and low temperature according to the temperature after the reaction. At present, global resources are becoming increasingly scarce, and making full use of the reaction heat in the chemical production process is an indispensable and important part of industrial production. At present, there are mature recovery processes at home and abroad to recover this heat, so that the heat recovery rate of sulfuric acid reaction reaches more than 95%. Among them, the high and medium temperature energy recovery technology is relatively simple and mature due to the high temperature, while the low temperature recovery technology started late. Although there is a mature recovery process, there is still room for improvement in the selection of equipment and materials.

[0003] As a dilute acid preheater for heat recovery equipment in sulfuric acid production, the dilute acid preheater currently mainly adopts shell and tube type, and the heat exchange tube mainly adopts metal heat exchange tube. At present, the metal heat exchange tube can operate stably for a long time for high-temperature and high-concentration sulfuric acid, but when the acid concentration is lower than 93%, it cannot guarantee long-term stable operation, especially under high acid temperature conditions, the corrosion rate of the metal heat exchange tube is fast, and it cannot meet the needs of sulfuric acid production. Silicon carbide heat exchange tubes have corrosion resistance and higher heat exchange efficiency than metal heat exchange tubes, but the length of silicon carbide heat exchange tubes should not be too long, usually about 3 meters, which leads to the single shell and tube heat exchanger cannot meet the heat exchange requirements. In addition, in order to ensure sufficient heat exchange and play an auxiliary supporting role for the heat exchange tube, baffles are set inside the shell and tube heat exchanger. The baffle can extend the path of the heat exchange fluid, thereby improving the heat exchange effect, but the baffle will form a certain obstruction to the fluid, not only slowing down the flow rate of the fluid, but also the impact of the fluid on the baffle will cause vibration, which needs to be improved. Utility Model Content

[0004] In order to solve the problems mentioned in the background technology, the purpose of the utility model is to provide a sulfuric acid preheater for use in a low-temperature waste heat recovery system.

[0005] In order to achieve the above objectives, the technical solution of the utility model is:

[0006] A sulfuric acid preheater for a low-temperature waste heat recovery system comprises a shell, a head, a tube sheet, a silicon carbide heat exchange tube bundle and a baffle. Shell interfaces are provided at both ends of the shell in the length direction, and a head interface is provided on the head. There are multiple shells, and the multiple shells are connected head to tail through flanges and two tube sheets are sandwiched between the two connected shells. The outer ends of the two shells located at the ends are connected to the head through flanges and a tube sheet is sandwiched between the head and the shell. Tube sheet holes are opened on the tube sheets, and two relatively arranged tube sheets are sealed and installed with silicon carbide heat exchange tube bundles through the tube sheet holes, and the silicon carbide heat exchange tube bundles in several shells are connected, and two adjacent shell interfaces are connected by pipelines. Baffles are staggered in each shell, and the baffles are sleeved on the silicon carbide heat exchange tube bundle, and the baffles are bent toward one of the heads.

[0007] Furthermore, the shell and the head are both lined with polytetrafluoroethylene, the tube sheet and the tube sheet holes are lined with polytetrafluoroethylene, and the tube sheet holes and the silicon carbide heat exchange tube bundle are sealed with polytetrafluoroethylene O-rings.

[0008] The beneficial effects of the utility model are as follows: the silicon carbide heat dissipation tube bundle is adopted to ensure corrosion resistance and improve heat exchange efficiency; multiple shells are connected end to end to form a series connection, which solves the defect of the short length of the silicon carbide heat dissipation tube bundle and also reduces the use of heads accordingly, thereby reducing equipment costs; the baffle is designed to bend toward one of the heads, which reduces the resistance of the baffle to the fluid to a certain extent, thereby reducing the vibration of the baffle and improving the service life of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a structural schematic diagram of the utility model.

[0010] Explanation of the accompanying drawing numbers: 11. Shell interface, 21. Head interface, 3. Tube sheet, 4. Silicon carbide heat exchange tube bundle, 5. Baffle, 6. Pipeline. DETAILED DESCRIPTION

[0011] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field belong to the protection scope of the utility model.

[0012] like Figure 1As shown, a sulfuric acid preheater used in a low-temperature waste heat recovery system includes a shell 1, a head 2, a tube sheet 3, a silicon carbide heat exchange tube bundle 4 and a baffle 5. Both ends of the shell 1 in the length direction are provided with a shell interface 11, and the head 2 is provided with a head interface 21. There are two shells 1, one end of the two shells 1 is connected to each other through a flange, and two tube sheets 3 are sandwiched between the connected ends of the two shells 1. The opposite ends of the two shells 1 are connected to the head 2 through a flange, and the tube sheet 3 is sandwiched between the head 2 and the shell 1. Tube sheet holes are opened on the tube sheet 3, and the two tube sheets 3 arranged opposite to each other are sealed and installed with the silicon carbide heat exchange tube bundle 4 through the tube sheet holes, and the silicon carbide heat exchange tube bundles 4 in the two shells 1 are connected to each other. The two adjacent shell interfaces 11 are connected by pipelines 6, and baffles 5 are staggered in each shell 1. The baffles 5 are sleeved on the silicon carbide heat exchange tube bundle 4, and the baffles 5 are bent toward the left head 2. The head interface 21 on the left is upwardly arranged as a high-temperature sulfuric acid inlet, and the head interface 21 on the right is downwardly arranged as a high-temperature sulfuric acid outlet. The shell interface 11 on the left is upwardly arranged as a dilute acid outlet, and the shell interface 11 on the right is downwardly arranged as a dilute acid inlet, wherein the shell 1 and the head 2 are both lined with polytetrafluoroethylene, the tube sheet 3 and the tube sheet holes are lined with polytetrafluoroethylene, and the tube sheet holes and the silicon carbide heat exchange tube bundle 4 are sealed with polytetrafluoroethylene O-rings.

[0013] In actual use, the diluted acid enters the shell 1 from the shell interface 11 on the right, passes through the two shells 1, and is discharged from the shell interface 11 on the left, while the high-temperature sulfuric acid enters the head 2 from the head interface 21 on the left, passes through two sections of silicon carbide heat exchange tube bundles 4, and is discharged from the head interface 21 on the right, thereby realizing heat exchange between the diluted acid and the high-temperature sulfuric acid and achieving the effect of preheating the diluted acid. The silicon carbide heat exchange tube bundle 4 itself has corrosion resistance and higher heat exchange efficiency than the metal heat exchange tube bundle, which can improve the steam production rate of the low-temperature waste heat recovery system, and the shell 1, head 2, and tube sheet 3 are all lined with polytetrafluoroethylene, so the whole device has strong corrosion resistance, and the baffle 5 is bent to the left, which can reduce the resistance to the diluted acid, thereby reducing the vibration of the baffle 5 itself, which can effectively improve the life of the equipment.

[0014] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. All modifications, equivalent substitutions, improvements, etc. within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A sulfuric acid preheater for a low-temperature waste heat recovery system, comprising a shell, a head, a tube sheet, a silicon carbide heat exchange tube bundle and a baffle, wherein both ends of the shell in the length direction are provided with a shell interface, and the head is provided with a head interface, characterized in that: There are multiple shells, and the multiple shells are connected head to tail through flanges and two tube sheets are sandwiched between the two connected shells. The outer ends of the two shells located at the ends are connected to heads through flanges and a tube sheet is sandwiched between the heads and the shells. Tube sheet holes are opened on the tube sheets, and two relatively arranged tube sheets are sealed and installed with silicon carbide heat exchange tube bundles through the tube sheet holes, and the silicon carbide heat exchange tube bundles in several shells are connected, and the two adjacent shell interfaces are connected by pipelines. Baffles are staggered in each shell, and the baffles are sleeved on the silicon carbide heat exchange tube bundle, and the baffles are bent toward one of the heads.

2. The sulfuric acid preheater used in a low-temperature waste heat recovery system according to claim 1, characterized in that: The shell and the head are both lined with polytetrafluoroethylene, the tube sheet and the tube sheet holes are lined with polytetrafluoroethylene, and the tube sheet holes and the silicon carbide heat exchange tube bundle are sealed with polytetrafluoroethylene O-rings.

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