[Q&A Question 231] 2016.12.07
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【Q&A Question 231】December 07, 2016: What temperature or pressure limits should the reaction system pay attention to during the shutdown for catalyst replacement in hydroprocessing? The reference answers will be visible after responding; points are awarded by identifying the key points. (1) During the shutdown and cooling process of the catalyst, as long as the CO content in the recycled hydrogen is below 30 ppm, the temperature of the catalyst must remain above 205°C to prevent the formation of highly toxic nickel carbonyl. (2) During the process of cooling and reducing the flow rate, it is necessary to follow the principle of cooling first and then reducing the flow rate, in order to prevent the catalyst bed and furnace tubes from overheating. (3) Prevent excessive reactor pressure drop caused by oil temperature being too low. (4) When the reaction temperature is greater than 200°C, the use of a hot hydrogen cycle without hydrogen sulfide is not allowed to prevent sulfur loss from the catalyst. (5) Before opening the reactor, it must be cooled to below 50°C to reduce the risk of spontaneous combustion of the hydrocarbon-oxygen mixture and iron sulfide. (6) When adjusting the E-102 side line by cooling down, the speed of the hydrogenation unit must not be too high to prevent the temperature in D-103 from rising excessively. (7) Maintain the cooling rate below 25°C/h. Summary post of Q&A from 2016 (updated up to December~~~~) http://bbs.hcbbs.com/thread-1597792-1-1.html Seeking sponsors for the “2016 Haichuan Top 10 Members Selection Contest” http://bbs.hcbbs.com/thread-1628108-1-1.html (Source: Haichuan Chemicals Forum)
1) During the shutdown and cooling process of the catalyst, as long as the CO content in the recycled hydrogen is below 30 ppm, the temperature of the catalyst must remain above 205°C to prevent the formation of highly toxic nickel carbonyl. (2) During the process of cooling and reducing the flow rate, it is necessary to follow the principle of cooling first and then reducing the flow rate, in order to prevent the catalyst bed and furnace tubes from overheating. (3) Prevent excessive reactor pressure drop caused by oil temperature being too low. (4) When the reaction temperature is greater than 200°C, the use of a hot hydrogen cycle without hydrogen sulfide is not allowed to prevent sulfur loss from the catalyst. (5) Before opening the reactor, it must be cooled to below 50°C to reduce the risk of spontaneous combustion of the hydrocarbon-oxygen mixture and iron sulfide. (6) When adjusting the E-102 side line by cooling down, the speed of the hydrogenation unit must not be too high to prevent the temperature in D-103 from rising excessively. (7) Maintain the cooling rate below 25°C/h.
1) During the shutdown and cooling process of the catalyst, as long as the CO content in the recycled hydrogen is below 30 ppm, the temperature of the catalyst must remain above 205°C to prevent the formation of highly toxic nickel carbonyl. (2) During the process of cooling and reducing the flow rate, it is necessary to follow the principle of cooling first and then reducing the flow rate, in order to prevent the catalyst bed and furnace tubes from overheating. (3) Prevent excessive reactor pressure drop caused by oil temperature being too low. (4) When the reaction temperature is greater than 200°C, the use of a hot hydrogen cycle without hydrogen sulfide is not allowed to prevent sulfur loss from the catalyst. (5) Before opening the reactor, it must be cooled to below 50°C to reduce the risk of spontaneous combustion of the hydrocarbon-oxygen mixture and iron sulfide. (6) When adjusting the E-102 side line by cooling down, the speed of the hydrogenation unit must not be too high to prevent the temperature in D-103 from rising excessively. (7) Maintain the cooling rate below 25°C/h.
When replacing the catalyst in the reactor, the temperature inside the reactor is kept below 50 degrees; nitrogen is used for protection at a pressure of around 0.2 MPa, and the removed catalyst is cooled by spraying water or using dry ice. I haven’t carried out catalyst deactivation work specifically yet; I need to learn about it
During the shutdown and cooling process of the catalyst, as long as the CO content in the recycled hydrogen is above 30 ppm, the temperature of the catalyst must remain above 205°C to prevent the formation of highly toxic nickel carbide.
During the shutdown and cooling process of the catalyst, as long as the CO content in the recycled hydrogen is above 30 ppm, the temperature of the catalyst must remain above 205°C to prevent the formation of highly toxic nickel carbide.
The reactor inlet and outlet are isolated using blind flanges, and nitrogen is continuously purged through the reactor to prevent air from entering; the temperature is maintained at room temperature!
(1) During the shutdown and cooling process of the catalyst, as long as the CO content in the recycled hydrogen is below 30 ppm, the temperature of the catalyst must remain above 205°C to prevent the formation of highly toxic nickel carbonyl. (2) During the process of cooling and reducing the flow rate, it is necessary to follow the principle of cooling first and then reducing the flow rate, in order to prevent the catalyst bed and furnace tubes from overheating. (3) Prevent excessive reactor pressure drop caused by oil temperature being too low. (4) When the reaction temperature is greater than 200°C, the use of a hot hydrogen cycle without hydrogen sulfide is not allowed to prevent sulfur loss from the catalyst. (5) Before opening the reactor, it must be cooled to below 50°C to reduce the risk of spontaneous combustion of the hydrocarbon-oxygen mixture and iron sulfide. (6) When adjusting the E-102 side line by cooling down, the speed of the hydrogenation unit must not be too high to prevent the temperature in D-103 from rising excessively. (7) Maintain the cooling rate below 25°C/h