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Leakage: During the heating up of the equipment, thermal expansion and thermal stress can cause minor leaks at the flange and gasket joints. In the event of such a leak, a steam hose should be placed at the leak site to disperse the oil and gas, thereby preventing ignition until the leak can be fixed. The leak location can be detected using ultrasonic devices and gas detectors, or it can be inspected with soapy water at the flange. To minimize the risks associated with thermal expansion, the heating rate should generally not exceed 25 °C/h. Explosive mixtures: Hydrocarbons must not be introduced into process pipelines or containers until all air has been removed. Before introducing hydrocarbon feedstocks, all equipment must be purged with inert gas or steam. The danger of water: Hot oil must never be added to systems that contain even small amounts of water. Reaction systems are dried using circulating hot gas, and after pressure testing of distillation systems, liquid is drained by applying gas pressure. Any water remaining in the system is first flushed with cold oil, then with hot oil during circulation, before being discharged from the bottom of the containers, low points in the pipes, and pumps. Equipment damage due to vacuum: The buffer tanks for fresh feedstocks and all containers in the distillation section may not be designed to handle vacuum conditions. Such equipment must not be left closed after being exposed to steam. Since steam condensation occurs when the equipment cools down, this can create a vacuum. Before shutting off the steam, measures must be taken to prevent the formation of such a vacuum. The temper brittleness of the reactor material: Equipment manufactured from 2.25Cr-1Mo and 3Cr-1Mo materials both suffer from the problem of temperature brittleness (temper brittleness). This phenomenon is characterized by a significant increase in the critical temperature; below this temperature, if the pressure rises further (even if it is far below the designed operating pressure), sudden and severe cracking may occur. Above this temperature, the inherent toughness of the material prevents cracking. To avoid temper brittleness, when the equipment is airtight, the pressure and temperature must be increased simultaneously as required