How to carry out temperature cooling and passivation of hypervariable catalysts? What issues should be paid attention to?

The high-temperature furnace and the first and second stage furnaces are operated at the same time, the steam is cooled and passivated, the cooling rate is 50 degrees/hour, the steam volume is 50 tons, the temperature is maintained for 4 hours, and then the simultaneous fire reduction and steam reduction are started. Reduce the temperature to 320 degrees and remove the steam. Pour in nitrogen to cool down. It can only be released when it is less than 80 degrees.

What is said above is absolutely true. This is generally the case. Ours is a Kellogg process. The cooling passivation is the same as the one above. The steam is vented through the low-variation inlet vent valve.

The most commonly used is the direct cooling passivation method. Including two processes: cooling and oxidation. 1 Cool down: Before stopping, increase the steam appropriately to lower the temperature of the catalyst bed. After stopping, close the valves in the decarbonization and compression section, use superheated steam to cool down, and replace the carbon monoxide and hydrogen in the catalyst bed. The steam flow rate is equivalent to an air speed of 100-300/h, and the bed cooling rate is 50 degrees Celsius/h. When the bed temperature drops to 200 degrees Celsius and the furnace outlet gas (carbon monoxide and hydrogen) is less than 0.5%, it enters the oxidation stage. 2 oxidation: A small amount of air is added to the steam introduced into the conversion furnace to oxidize ferric oxide on the surface of the catalyst into ferric oxide and release a large amount of heat. The amount of air added increases gradually from large to small, and the oxygen content in the gas gradually increases from 0.5% to 1%... The temperature will gradually rise when the catalyst is oxidized. Pay close attention to the temperature rise and adjust the ratio of steam to air in time to prevent the temperature from rising sharply. The maximum temperature of oxidation cannot exceed 400 degrees Celsius, and the oxidation temperature rise rate does not exceed 50 degrees Celsius/h. After oxidation for a period of time, when the furnace temperature drops to 200 degrees Celsius, increase the amount of air. Repeat this many times until a large amount of air is introduced and the furnace temperature no longer rises. When the oxygen content of the gas at the outlet of the conversion furnace reaches more than 20%, the oxidation can be considered completed. Then use air and steam to cool down. Stop the steam when the furnace temperature drops to about 200 degrees Celsius. Use air to cool down to below 60 degrees Celsius to open the manhole to unload the catalyst. The following issues should be paid attention to when cooling and passivating: 1 For catalysts that are intended to continue to be used, the cooling rate should be controlled at 50 degrees Celsius/h during passivation, and the maximum temperature of the catalyst bed should not exceed 400 degrees Celsius during oxidation. When the air cooling bed temperature drops to 120 degrees Celsius, no more steam is allowed to be added to the system, and the cooling gas is not allowed to contain water at this time. When the catalyst is unloaded after passivation, it should be placed in an iron drum and sealed. It is strictly prohibited to get wet or fall. 2. The cooling rate of the catalyst when it is to be scrapped can be appropriately accelerated. The maximum temperature of the catalyst bed during oxidation should not exceed 600 degrees Celsius to prevent the furnace and thermocouple from burning out.