Hydrolysis reaction operations during hydrogenation shutdown

Adhere to the principle of lowering blood pressure first before reducing temperature. The voltage reduction measure is achieved through multi-turn regulation of the new hydrogen machine. Temperature reduction is achieved by lowering the furnace load and adjusting the amount of circulating hydrogen. With the same degree of reduction in furnace load, the greater the amount of circulating hydrogen, the faster the temperature drops; the smaller the amount of circulating hydrogen, the slower the temperature drops. In hydrogen-containing systems during operation, hydrogen penetration occurs in the steel; that is, when the system temperature is above 135°C, the metal lattice becomes large enough for hydrogen molecules to move in and out of it freely. Therefore, during shutdown, the cooling rate must not be too fast, so as to allow hydrogen molecules to gradually escape from the lattice. Otherwise, if the hydrogen molecules cannot escape completely, hydrogen bubbling will occur. Therefore, the cooling rate is set at 30°C/h, but the hydrogen-containing system must not drop below 135°C. At startup, the voltage can be increased first before raising the temperature. Hydrogen embrittlement refers to the phenomenon where hydrogen penetrates into steel and reacts with the carbon in the steel to form methane, resulting in hydrogen bubbles or embrittlement. Parking procedure: Stop the operation and drain the oil, adhering to the principle of maintaining constant pressure, cooling first before reducing the volume. The hot hydrogen cycle carries oil, pushing it outward from high pressure areas. Generally, the pressure should be maintained at no less than 20 kilograms and the temperature at no less than 150°C; the process of transferring oil ends when the high-pressure tank is empty of oil. Vacuum is created and then nitrogen is used for displacement; the temperature and pressure are increased, and heat is applied to cause hydrogen to be released from the nitrogen. This process continues until the hydrogen plus hydrocarbon content in the circulating nitrogen is no more than 0.5% and stops increasing any further. Due to the high permeability of hydrogen molecules, it is necessary to dehydrogenate the reactor during shutdowns in order to prevent hydrogen embrittlement and hydrogen bubbling caused by hydrogen molecules penetrating into chromium-molybdenum steel during production. Reduce the reaction temperature of CAT at a rate of 20 degrees per hour to 275 degrees, and maintain this temperature for 12 hours. Lower the reaction pressure to 4.0 MPa; the reason for this pressure reduction is that the molecular weight of hydrogen molecules is much lower than that of nitrogen molecules – nitrogen’s molecular weight is 14 times that of hydrogen. Otherwise, the outlet of the recycle hydrogen compressor would overheat. During the pressure reduction process, keep the speed of the recycle machine at 8000 rpm, and supply nitrogen through the new hydrogen compressor to maintain the pressure. If the pressure cannot be maintained, reduce the speed of the recycle machine accordingly ； Analyze the oxygen content in nitrogen

Can the voltage be increased first and then the temperature when starting up? Did the original poster get it backwards?

May I ask that the principle of lowering blood pressure first and then reducing temperature be adhered to? ----------Stop production and remove oil, adhering to the principle of keeping pressure constant while first reducing temperature and then reducing volume – isn’t that contradictory?

Here, we first reduce the volume while keeping the pressure basically unchanged; hot hydrogen is still needed to carry the oil. It’s true that the heating furnace first cools down before reducing the volume