Maintenance method and operation instructions of shell and tube heat exchanger
Tubular heat exchanger is the most widely used heat exchanger in chemical production. It has a simple structure, high heat exchange efficiency and strong adaptability (can be used under high or low temperature, high or low pressure conditions) .
The main structure of a tandem tube heat exchanger is composed of a tube bundle composed of a plurality of parallel arranged tubes in a cylindrical shell.
Both ends of the casing and the end cover are provided with flanges, and the end cover and the casing are connected by bolts.
The shell and the end cover are respectively provided with small inlet and outlet flanges for the two media to facilitate the corresponding pipeline connection.
Pipe-and-tube heat exchangers commonly used in chemical production include fixed tube plate type, floating head type, U-shaped tube type and the shell with heat compensation function.
The main structural components of the fixed tube-sheet type shell-and-tube heat exchanger are: head; heat exchange tube; baffle plate; shell; support; tube plate.
The tube plate (also called flower plate) forms a non-detachable fixed connection with the two ends of the shell.
The two ends of the tube are connected to the tube sheet by expansion welding. In order to change the flow direction of the medium between the tubes and improve the heat exchange efficiency, several baffles are provided on the inner wall of the shell.
The end caps at both ends are connected with the housing in the form of flanges.
There are two different media flowing in and between the tubes.
In order to improve the heat exchange efficiency of the heat exchanger, sometimes a partition is installed in the head to form a fluid distribution chamber, which constitutes a so-called double-tube-type tube-type heat exchanger or a four-pass-type tube-type heat exchanger.
Preparation before installation
Do a good job of the preparation work before the installation of the heat exchanger, which can make the installation work smoothly, meet the technical specifications of the installation, and ensure the installation quality.
site preparation for construction
According to the plan of the construction site, conduct actual surveys on other aspects of the site, and determine whether the transportation route, parking position, unloading position and surrounding environment will affect the transportation and installation of the equipment, and cooperate with relevant parties to meet the requirements of the lifting conditions. To unblock the transportation roads, it is necessary to ensure that the roads are smooth and solid, so that the vehicles can pass smoothly, and the heat exchanger is safely transported to the site. The installation width should meet the installation requirements.
Acceptance of heat exchange equipment
The drawings of Lu'an equipment are carefully and carefully checked, including the model, quality, geometric dimensions, nozzle orientation, technical characteristics, etc. of the equipment. Check the technical documents such as factory certificate, instruction manual, quality guarantee. Inspect the equipment for damage and missing parts (including horns, bolts, washers, accessories, etc.). Make inspections and acceptance records.
Before installing the heat exchanger, the foundation must be carefully inspected and handed over for acceptance. The basic construction unit shall submit quality certificates, measurement records and related construction technical data. There should be obvious elevation lines and vertical and horizontal centerlines on the foundation, and the foundation should be cleaned up, and any defects should be handled.
, Hoisting preparation
The hoisting department should prepare all the rigging, such as cranes, poles, wire ropes, pulley blocks, reverse chains and snap rings, etc., and do a good job of inspection in accordance with safety regulations. For large heat exchangers, because of the large diameter, many heating tubes, and heavy lifting weight, the lifting binding part should be selected at the shell support with a reinforcing pad, and wood blocks should be set on both sides of the shell to protect the shell. So as not to be deformed when the shell is pressed by the wire rope during lifting.
, Write a construction plan
In order to make the installation work orderly, a construction plan should be prepared before installation. The content of the construction plan should include preparation instructions, preparation basis, project overview, construction preparation, construction methods and measures, technical measures and technical requirements, construction equipment, and construction use. Materials, deployment of construction personnel, construction plan schedules, etc.