Precautions for using graphite reboilers

Graphite cannot withstand sudden changes in temperature, otherwise it will crack; similarly, excessive force should not be used when tightening flanges, as this can also cause the graphite to crack

I. Installation Precautions When installing a graphite heat exchanger, in addition to complying with the general rules for installation work, the following precautions should also be observed: 1. Due to transportation and handling, the connecting bolts may become loose, which can lead to leaks at the gaskets and O-rings. Therefore, these parts should be carefully inspected and adjusted before installation, and a horizontal (inside-the-shell) pressure test should be carried out in accordance with the specifications provided in the factory certificate. 2. During lifting, handle the item gently; it is not allowed to touch the ground or drag it while lifting. Exposed graphite pieces must never be moved using levers or tied up with steel wires. 3. When performing electric or gas welding on the steel shell, it must be filled with water first before proceeding. 4. This equipment is installed vertically; the user shall fabricate its own supports, which are secured to it using the bolt holes provided at the bottom. 5. The verticality of the equipment after installation must meet the installation requirements. II. Precautions for Use 1. When starting up or shutting down the system, avoid damage to the heat exchange elements (due to thermal shock) and the resin (due to high-temperature aging) caused by sudden temperature changes. When opening or closing the valves for the material and steam, adjust the flow rate gradually to its maximum or minimum value. 2. A pressure gauge shall be installed on the steam inlet pipeline, and the inlet steam pressure must not exceed the design pressure of the equipment ； The pressure fluctuations of the traps installed on the outlet pipeline meet the pressure requirements. Avoid sudden changes in operating pressure and temperature, as well as use under conditions of over-temperature or over-pressure. 3. When this equipment is used as a reboiler, it should first be filled with a cold carrier (the material medium); once the equipment is completely filled, the steam valve should be opened slowly. The heat exchange elements should be preheated first, with the pressure inside the equipment increasing at a rate of 0.02 MPa per minute. After more than 30 minutes, the pressure will reach the requirements specified for the process (or design pressure) ； When stopping the operation, the heat carrier (steam or hot water) should be stopped first; only after the equipment has cooled down should the cold carrier (the material medium) be stopped. 4. During use, it is necessary to regularly remove the non-condensable gases at the top of the shell and the condensed water at the bottom. 5. When parking in winter, drain out the hot and cold materials to prevent the equipment from being damaged by low temperatures. 6. If there is leakage at the O-rings or gaskets, stop the operation and adjust the tightening bolts. Leakage persisted after adjustment; the machine was stopped, steam and longitudinal material inside the shell were removed, and the O-rings and gaskets were replaced again. 7. When leakage is detected in the heat exchange block inside the shell, operations should be stopped for inspection and repair. Equipment that has been overhauled can be put into use only after passing pressure testing. 8. Periodically test the acidity and alkalinity of the steam to assess the condition of the equipment. When a leak is detected, address it promptly. 9. When connecting the graphite pipe fittings, the bolts should be tightened symmetrically and with even force; forced tightening of the bolts should be avoided to prevent damage to the graphite pipe fittings.