Regarding the operation of the hydrogenation reactor?

6.5 Pretreatment of exhaust gas hydrogenation catalyst with sulfur 1) Condition confirmation – The sulfur recovery unit has been fed with materials and is now in normal operation； – The exhaust gas treatment section has completed system heating; the temperature of the catalyst bed in the exhaust gas hydrogenation reactor is around 200℃ ； – The exhaust gas quench tower and the exhaust gas absorption tower have established a circulation system, thus meeting the conditions to receive exhaust gas ； – Confirm that the online analyzer for exhaust hydrogen concentration is ready for operation. 2) Recommended pre-sulfidation process for the exhaust gas hydrogenation catalyst (1): Sulfur-recovered flue gas passes through the exhaust gas liquid separation tank → reduction gas generator → exhaust gas hydrogenation reactor → steam generator → exhaust gas incinerator → exhaust gas waste heat boiler → and is then discharged through the chimney ； 3) Recommended pre-sulfidation procedure for the exhaust gas hydrogenation catalyst – The pre-sulfidation of the catalyst during its first installation should be carried out under the supervision of the catalyst supplier’s technical staff on site ； The pre-sulfurization procedure should be approved by the catalyst supplier or provided by the catalyst supplier ； – Adjust the air supply to the reducing gas generator to achieve equivalent combustion; the purpose of equivalent combustion is to prevent the generation of H2 in the reducing gas generator during the catalyst presulfidization stage, so as to avoid \"metallization\" of the exhaust gas hydrogenation catalyst. To prevent carbon deposition due to combustion, a small amount of steam can be introduced ； – Adjust the air-fuel ratio of the sulfur production furnace to bring the H2S/SO2 ratio in the sulfur production exhaust gases to 4–6/1, or to have an H2S concentration of 1–2% (v) ； – If the sulfur production off-gas system is used for heating, catalyst presulfurization shall be carried out according to this procedure ； If heating is carried out using the exhaust gas recirculation fan system, the exhaust gas recirculation should be stopped, and the process should be changed to step 6.4, 2) exhaust gas hydrogenation catalyst presulfidization process ； – Catalyst presulfurization takes approximately 1 to 2 days. After introducing the sulfur production off-gases with an H2S concentration of 1–2% (v), the H2S concentration in the gases at the inlet and outlet of the off-gas hydrogenation reactor should be analyzed once per hour. During presulfurization, the concentration decreases as H2S is consumed ； The H2S concentration remains unchanged, indicating that pre-sulfidation has been completed ； – Heat the hydrogenation reactor bed at a rate of 5°C/h until it reaches 250°C, where it is held at this temperature for pre-sulfidization ； – Adjust the reducing gas generator to a sub-chemical-equivalent air supply, and contact the automation maintenance personnel to activate the AT03002 online H2 analyzer on pipe P-03016, in order to keep the H2 concentration in the exhaust gas system at 1–2% ； – The pre-sulfidized exhaust gas is directed to the exhaust gas quench tower and the exhaust gas absorption tower. The flow path is as follows: the sulfur recovery flue gas passes through the exhaust gas liquid separation tank → pipe P-03011 → reduction gas generator → pipe P-03012 → exhaust gas hydrogenation reactor → pipe P-03013 → steam generator → pipe P-03014 → exhaust gas quench tower → pipe P-03015 → exhaust gas absorption tower → pipe P-03016 → exhaust gas incinerator → exhaust gas waste heat boiler → and is then discharged through the chimney ； – Start the LIC03010 automatic control valve to maintain the liquid level at the bottom of the exhaust gas quench tower at a normal level ； Operate the emergency cooling water cooler to keep the temperature of the circulating emergency cooling water at or below 40℃ ； Monitor the pH of the quench water to ensure it remains at least 6, and add ammonia to the quench water system promptly to maintain a pH of 6–8 ； Adjust the amount of quench water circulating to keep the top temperature of the exhaust gas quench tower at or below 40℃ ； – Change the cold-cycle process of the exhaust gas absorption tower to the normal production process: The lean amine solution supplied from the solvent regeneration unit passes through the control valve FV03020 to have a flow rate of 25–35 t/h; the lean amine solution cooler is used to maintain its temperature at 35–40°C. The solution then flows into the exhaust gas absorption tower, through pipe RSM-03005, and to the rich amine solution pump. The control valve LV03011 is used to keep the liquid level in the exhaust gas absorption tower at the appropriate level, after which the rich amine solution returns to the amine solution regeneration unit ； – Automatically monitor and adjust the hydrogen concentration in the purified exhaust gases based on the H2 signal from the online analyzer AT03002 ； – After pre-vulcanization at a constant temperature of 250°C until the H2S concentrations of AP-106 and AP-107 remained unchanged, the temperature of the exhaust gas hydrogenation reactor was increased at a rate of 10–20°C to 290–300°C, with the inlet temperature of the exhaust gas hydrogenation reactor maintained between 280–300°C℃ ； – Adjust the air-fuel ratio of the sulfur production furnace to bring the H2S/SO2 ratio in the sulfur production exhaust gases to 2/1; once the pre-sulfidation of the exhaust gas hydrogenation catalyst is complete, normal production can resume.

There is information on hydrogenation reactors on the forum: http://bbs.hcbbs.com/thread-272844-1-1.html