All-low-variation process

During the operation of the catalyst, sudden and significant changes in process conditions are not allowed. It is necessary to maintain stability in various operational parameters such as temperature, pressure, water/gas levels, and hydrogen sulfide concentration, to minimize the number of start-up and shutdown cycles, and to avoid operating without sulfur or having too low a sulfur content. Pay attention to the pressure difference changes in each reactor; when operating conditions change or abnormalities occur, it is necessary to monitor the CO content at the outlet, and adjust various parameters as needed. When catalyst activity declines after prolonged operation and the outlet CO level increases, the inlet temperature can be increased gradually by a small amount to keep the outlet CO level within the designed range. During production, strict control is exercised to prevent water from entering the catalyst bed of the converter. When the temperature of the shift converter rises due to excessive oxygen content, remember not to use steam for cooling. To achieve cooling, measures such as first reducing the steam volume, then reducing the gas volume, and lowering the inlet temperature should be taken ； In an emergency, the temperature of the catalyst layer soars, triggering an emergency shutdown.

Strictly speaking, there is no distinction between early and late stages; in the late stage as well, it is important to avoid bringing water or oil, and to ensure that levels of gas and oxygen are not too high. It’s just that the catalyst has lower activity in the later stages; therefore, it is necessary to operate at a higher temperature to prevent temperature fluctuations. Additionally, if production conditions permit, it is better to keep the sulfur content in the gas at a higher level.

To what extent can the temperature be increased through import heating?

This post was last edited by TH373637 on 2012-11-11 17:49. Control during production to strictly prevent water from entering the catalyst bed of the converter. When the temperature of the shift converter rises due to excessive oxygen content, remember not to use steam for cooling. To achieve cooling, measures such as first reducing the steam volume, then reducing the gas volume, and lowering the inlet temperature should be taken ； In an emergency, the temperature of the catalyst layer soars, triggering an emergency shutdown.

Based on the catalyst’s reaction performance and the composition of the gas exiting the reactor, the reaction is not optimal; increasing the bed temperature could help. Additionally, the bypass system can be adjusted accordingly

If the oxygen level rises rapidly and is difficult to control, it is not necessary to stop the machine; instead, instruct the compressor to open the high-pressure circuit valve. Qualified H2 and N gases are even better

1. It is strictly prohibited to bring water into the furnace. Because water can dissolve the potassium salts, which are the active components in low-temperature catalysts, thereby permanently deactivating the catalyst. 2. The process gas entering the low-temperature shift reactor must be clean, free from dust and other impurities from high-temperature shift catalysts, especially in full low-temperature shift processes. The entry of oily substances into the low-temperature transformer is strictly prohibited. 3. Control the appropriate steam-to-gas ratio and sulfide content. To prevent reverse sulfidation reactions, the steam-to-gas ratio is controlled as low as possible, depending on the operating temperature of the low-temperature shift catalyst, while ensuring the desired conversion rate ； The sulfur compound content in the gas should also be kept at a level low enough to meet the requirements of the operating conditions. 4. At the beginning of use, the bed temperature of the low-temperature shift catalyst should be kept as low as possible, and it should then be increased gradually, with an increase of no more than 10 degrees per year. 5. The bed temperatures of the shift catalyst beds in each section should decrease from top to bottom, and the inlet temperature of the last bed should be kept as close as possible to the lower limit of the operating temperature.

“How can we achieve a as low as possible steam-to-gas ratio while ensuring the required conversion rate? What is the typical gas-to-steam ratio?

Pay attention to changes in conversion rate, as well as changes in system pressure difference.