【Q&A Question 175】2018.06.29
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【Q&A Question 175】June 29, 2018: Briefly describe the factors that affect changes in the purity of circulating hydrogen Answer: Refining; the cracking reaction temperature increases, and the purity decreases ； A decrease in the new hydrogen flow rate leads to a drop in purity ； The nitrogen content in the raw material increases, while its purity decreases ； Changes in the purity of new hydrogen ； Internal leakage in heat exchanger ； High-score temperature variation ； Changes in the amount of water injected during the reaction. (Unless otherwise specified, all questions and answers are based on hydrogenation units.) ) Correct: 3 wealth, Incorrect: 1 wealth ； Mass posting of posts – rated based on the lowest score ； Replies that are unrelated to the answer are considered spam and will be deleted immediately. For management purposes, if you need to view content from a few days ago, please go to https://bbs.hcbbs.com/home.php?mod=space&uid=3862647&do=thread&view=me&from=space through the summary post below. The APP short-video skill competition has begun! https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1951670
Factors that cause changes in the purity of circulating hydrogen include: ① An increase in the temperature of purification and cracking reactions, leading to a decrease in purity； ②The flow rate of new hydrogen decreases, and its purity drops ； ③The nitrogen content in the raw material increases, while its purity decreases ； ④Changes in the purity of new hydrogen ； ⑤Internal leakage in heat exchanger ； ⑥High-score temperature variation ； ⑦Changes in the amount of water injected during the reaction.
①As the refining reaction temperature rises, the purity decreases； ②The flow rate of new hydrogen decreases, and its purity drops ； ③The nitrogen content in the raw material increases, while its purity decreases ； ④Changes in the purity of new hydrogen ； ⑤Internal leakage in heat exchanger ； ⑥High-score temperature variation ； ⑦Changes in the amount of water injected during the reaction.
As the refining and cracking reaction temperatures increase, the purity decreases； A decrease in the new hydrogen flow rate leads to a drop in purity ； The nitrogen content in the raw material increases, while its purity decreases ； Changes in the purity of new hydrogen ； Internal leakage in heat exchanger ； High-score temperature variation ； Changes in the amount of water injected during the reaction.
①As the refining and cracking reaction temperatures increase, the purity decreases； ②The flow rate of new hydrogen decreases, and its purity drops ； ③The nitrogen content in the raw material increases, while its purity decreases ； ④Changes in the purity of new hydrogen ； ⑤Internal leakage in heat exchanger ； ⑥High-score temperature variation ； ⑦Changes in the amount of water injected during the reaction.
①As the refining and cracking reaction temperatures increase, the purity decreases； ②The flow rate of new hydrogen decreases, and its purity drops ； ③The nitrogen content in the raw material increases, while its purity decreases ； ④Changes in the purity of new hydrogen ； ⑤Internal leakage in heat exchanger ； ⑥High-score temperature variation ； ⑦Changes in the amount of water injected during the reaction.
①As the refining and cracking reaction temperatures increase, the purity decreases； ②The flow rate of new hydrogen decreases, and its purity drops ； ③The nitrogen content in the raw material increases, while its purity decreases ； ④Changes in the purity of new hydrogen ； ⑤Internal leakage in heat exchanger ； ⑥High-score temperature variation ； ⑦Changes in the amount of water injected during the reaction.
Answer: Refining and cracking reaction temperatures rise, and purity decreases； A decrease in the new hydrogen flow rate leads to a drop in purity ； The nitrogen content in the raw material increases, while its purity decreases ； Changes in the purity of new hydrogen ； Internal leakage in heat exchanger ； High-score temperature variation ； Changes in the amount of water injected during the reaction.
Factors that cause changes in the purity of circulating hydrogen include: ① An increase in the purification reaction temperature leads to a decrease in purity； ②The flow rate of new hydrogen decreases, and its purity drops ； ③The nitrogen content in the raw material increases, while its purity decreases ； ④Changes in the purity of new hydrogen ； ⑤Internal leakage in heat exchanger ； ⑥High-score temperature variation ； ⑦Changes in the amount of water injected during the reaction. Methods to improve the purity of recycled hydrogen: ① Control the nitrogen content in the effluent from the purification reactor ； ②Adjust and supplement with new hydrogen ； ③Control the temperature of the high-pressure separator properly ； ④Ensure the reaction water injection volume ； ⑤The unit generally does not adjust the purity of the recycled hydrogen; if its purity is below 85%, some of the waste hydrogen is discharged from the unit. A low purity of the recycled hydrogen leads to a decrease in the hydrogen partial pressure within the system, making hydrogenation reactions more difficult while dehydrogenation reactions become easier. As a result, the rate of carbon deposition on the catalyst increases; it is therefore necessary to discharge exhaust gases promptly and replenish with fresh hydrogen. At the same time, the reasons behind the decrease in the purity of the recycled hydrogen should be analyzed, and appropriate actions taken to address those issues.
New hydrogen purity, amount of new hydrogen, circulating hydrogen flow rate, reaction pressure, off-gas flow rate, properties of raw materials
1. Pressure of high-pressure separator； 2. Desulfurization and denitrification efficiency of the refining reactor ； 3. Supplement new hydrogen purity ； 4. Sulfur content in raw materials ； 5. Water injection volume.