Those working on conversion, come and study it
Thread Content
At our company, the facility for producing methanol from 100,000 tons of coke oven gas has been in operation for just over 2 months. However, the two reactors used for advanced desulfurization via medium-temperature oxidation of iron have lost much of their effectiveness. One of these reactors showed little improvement after being regenerated, and the sulfur content at its outlet was even higher than that at the inlet, indicating clear sulfur release. Could some expert please explain what the problem is? What are the requirements regarding sulfur content for iron oxide? :handshake
I’m not sure about you, but what is the sulfur content in coke oven gas? And what is the specific process involved?
It is likely that you did not follow the manufacturer’s instructions during the heating and reduction process of iron oxide. Next, I will discuss the precautions for heating the medium-temperature iron oxide we use; please share your thoughts on whether these measures are reasonable: a) During the heating process of HT-306 medium-temperature iron oxide using N2 gas, it is essential to keep the oxygen content in the N2 gas at or below 0.2%, and the temperature at the outlet of the heating furnace as well as the temperature at the hottest points in the catalyst layer must not exceed 120°C. The medium temperature shall not exceed 500°C. b) During the heating process, condensate water must be drained from each low-point drain every half hour to prevent liquid slugging or the formation of a liquid seal. c) The gas space velocity at elevated temperature can be controlled between 280–340 h-1; a higher value is preferable as it facilitates heat transfer and reduces the time required for heating and reduction. d) Superheated steam should be introduced when the bed temperature is 180°C; otherwise, condensation water will form, which will damage the mechanical strength of the desulfurizer and lead to severe pulverization. e) Strictly control the oxygen content in coke oven gas to ≤0.2%, and the total sulfur content to ≤20 mg/m3. f) During the temperature rise process, if any abnormalities are detected in the temperature readings, it is necessary to contact the instrument technician promptly to address the issue, in order to prevent false temperature indications and damage to the catalyst or equipment. Operators must strictly adjust the control according to the heating curve to prevent sudden spikes and drops in furnace temperature. g) During normal production, pressure should be increased slowly to prevent a rapid rise in temperature caused by too fast pressure increase
One more thing to add is that, during operation, the control of the catalyst bed temperature must also comply with the temperature requirements of the catalyst.
One additional point: After regeneration, medium-temperature iron oxide retains its properties only for emergency use; continuing to employ it is no longer meaningful. In such cases, it is recommended to replace it.