[Q&A Question 181] 2018.07.05
Thread Content
【Q&A Question 181】July 5, 2018: Briefly explain what causes scaling at the top of the reactor The reasons for fouling at the top include: ① Unstable raw materials from upstream units, as well as the lack of oxygen isolation in the raw material tanks, which lead to rapid coking in the higher-temperature areas of the furnace tubes, resulting in the deposition of particles such as carbon powder on the top of the bed ； ②The raw material contains iron, which rapidly reacts with H2S upon entering the reactor to form ferrous sulfide, which deposits on the surface of the catalyst and forms a hard crust ； ③The raw materials contain metal impurities such as silicon, sodium, and calcium, as well as inorganic salts, which deposit on the surface of the catalyst, block its pores, and cause the catalyst particles to stick together, forming a crust ； ④The crude oil contains mechanical impurities ； ⑤The crude oil or hydrogen contains chlorine, causing corrosion; iron ions are introduced into the reactor ； The effect of chloride ions and high temperatures causes certain compounds in the raw material to condense and coking on the surface of the furnace tube, while carbon powder particles enter the reactor and deposit on top of the catalyst. (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 skills competition has begun! https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1951670
(1) The raw materials supplied from the upstream units are unstable, and factors such as the absence of oxygen isolation in the raw material buffer tank lead to rapid coking in the higher-temperature areas of the furnace tubes, resulting in the deposition of particles such as carbon powder on the top of the bed layer； (2) Iron is present in the raw materials; it reacts rapidly with hydrogen sulfide upon entering the reactor to form ferrous sulfide, which deposits on the surface of the catalyst and forms a hard layer ； (3) The raw materials contain metal impurities such as silicon, sodium, and calcium, as well as inorganic salts, which deposit on the surface of the catalyst, block its pores, and cause the catalyst particles to stick together, forming a coating ； (4) The crude oil contains mechanical impurities ； (5) Chlorine in the feed oil or hydrogen causes corrosion, and iron ions are introduced into the reactor. The effect of chloride ions and high temperatures causes certain compounds in the raw material to condense and coking on the surface of the furnace tube, while carbon powder particles enter the reactor and deposit on top of the catalyst.
The reasons for scaling at the top of the reactor are: (1) Unstable feedstock from upstream units, as well as the absence of oxygen isolation in the feedstock buffer tank, which lead to rapid coking in the higher-temperature areas of the furnace tubes, resulting in the deposition of particles such as carbon powder on the top of the bed； (2) Iron is present in the raw materials; it reacts rapidly with hydrogen sulfide upon entering the reactor to form ferrous sulfide, which deposits on the surface of the catalyst and forms a hard layer ； (3) The raw materials contain metal impurities such as silicon, sodium, and calcium, as well as inorganic salts, which deposit on the surface of the catalyst, block its pores, and cause the catalyst particles to stick together, forming a coating ； (4) The crude oil contains mechanical impurities ； (5) Chlorine in the feed oil or hydrogen causes corrosion, and iron ions are introduced into the reactor. The effect of chloride ions and high temperatures causes certain compounds in the raw material to condense and coking on the surface of the furnace tube, while carbon powder particles enter the reactor and deposit on top of the catalyst.
The crude oil contains a high amount of gums and impurities; as it enters the reactor from the top, these impurities tend to accumulate in the upper layer
(1) The raw materials supplied from the upstream units are unstable, and factors such as the absence of oxygen isolation in the raw material buffer tank lead to rapid coking in the higher-temperature areas of the furnace tubes, resulting in the deposition of particles such as carbon powder on the top of the bed layer； (2) Iron is present in the raw materials; it reacts rapidly with hydrogen sulfide upon entering the reactor to form ferrous sulfide, which deposits on the surface of the catalyst and forms a hard layer ； (3) The raw materials contain metal impurities such as silicon, sodium, and calcium, as well as inorganic salts, which deposit on the surface of the catalyst, block its pores, and cause the catalyst particles to stick together, forming a coating ； (4) The crude oil contains mechanical impurities ； (5) Chlorine in the feed oil or hydrogen causes corrosion, and iron ions are introduced into the reactor. The effect of chloride ions and high temperatures causes certain compounds in the raw material to condense and coking on the surface of the furnace tube, while carbon powder particles enter the reactor and deposit on top of the catalyst.
(1) The raw materials supplied from the upstream units are unstable, and factors such as the absence of oxygen isolation in the raw material buffer tank lead to rapid coking in the higher-temperature areas of the furnace tubes, resulting in the deposition of particles such as carbon powder on the top of the bed layer； (2) Iron is present in the raw materials; it reacts rapidly with hydrogen sulfide upon entering the reactor to form ferrous sulfide, which deposits on the surface of the catalyst and forms a hard layer ； (3) The raw materials contain metal impurities such as silicon, sodium, and calcium, as well as inorganic salts, which deposit on the surface of the catalyst, block its pores, and cause the catalyst particles to stick together, forming a coating ； (4) The crude oil contains mechanical impurities ； (5) Chlorine in the feed oil or hydrogen causes corrosion, and iron ions are introduced into the reactor. The effect of chloride ions and high temperatures causes certain compounds in the raw material to condense and coking on the surface of the furnace tube, while carbon powder particles enter the reactor and deposit on top of the catalyst.
This post was last edited by Blue Flame on 2018-7-5 at 15:55. Answer: The reasons for scaling at the top include: ① Unstable raw materials from upstream units, as well as the absence of oxygen isolation in the raw material tanks; these factors lead to rapid coking in the higher-temperature areas of the furnace tubes, resulting in the deposition of particles such as carbon powder on the top of the bed layer； ②The raw material contains iron, which rapidly reacts with H2S upon entering the reactor to form ferrous sulfide, which deposits on the surface of the catalyst and forms a hard crust ； ③The raw materials contain metal impurities such as silicon, sodium, and calcium, as well as inorganic salts, which deposit on the surface of the catalyst, block its pores, and cause the catalyst particles to stick together, forming a crust ； ④The crude oil contains mechanical impurities ； ⑤The crude oil or hydrogen contains chlorine, causing corrosion; iron ions are introduced into the reactor ； Due to the effect of chloride ions and high temperatures, certain compounds in the raw material condense and coking on the surface of the furnace tube; carbon powder particles enter the reactor and deposit on top of the catalyst
Crude oil contains a high amount of gums, impurities, etc.; as the feed oil enters the reactor from the top, these impurities tend to accumulate in the upper layer.
1. The properties of the upstream raw materials are unstable; once coking occurs, the coke powder is carried into the reactor； 2. The raw materials are not isolated from air, leading to oxidation and the formation of gums ； 3. Metal ions present in the raw materials deposit on the surface of the catalyst, causing the catalyst particles to stick together ； 4. The feed oil contains mechanical impurities such as coke powder and rust, which are carried into the catalyst bed.