【Q&A Question 119】April 29, 2017
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【Q&A Question 119】April 29, 2017: What are the reasons for an increase in reactor pressure difference? The reference answers will be visible after responding; points are awarded by identifying the key points. (Unless otherwise specified, all questions and answers are based on hydrogenation units.) ) 1. Bed blockage; 2. Catalyst coking; 3. Catalyst crushing; 4. Blockage in the outlet collection box; 5. Increased feed rate or recycle hydrogen volume. Scoring criteria: 2 Wealth points for incorrect attempts; 3–8 points for *incomplete* answers. 10 Wealth points for correct answers, provided with a detailed explanation; 15–20 Wealth points if the answer is correct but lacks sufficient details. Please score according to these criteria. 2017 Q&A Summary Thread (updates have begun) http://bbs.hcbbs.com/thread-1657793-1-1.html 2017 Daily Question Summary Thread (updates have begun) http://bbs.hcbbs.com/thread-1657794-1-1.html 2016 Q&A Summary Thread (updates completed) http://bbs.hcbbs.com/thread-1597792-1-1.html Petrochemical Sector – “Creative Ideas for Energy Savings” campaign (sponsors sought; highest returns ever offered) http://bbs.hcbbs.com/thread-1666758-1-1.html Sponsors are being sought for this campaign; those interested can contact the event organizer. Petrochemical deep processing edition – the event to share pictures of chemical equipment has started! A vast amount of wealth, as well as HChuan coins, are waiting for you to claim them: http://bbs.hcbbs.com/thread-1760733-1-1.html. Notice regarding the collection of chemical engineering technical materials in the “Petroleum and Chemicals Section”: http://bbs.hcbbs.com/thread-1614796-1-1.html (Source: HChuan Chemical Engineering Forum)
Increased feed rate leads to catalyst pulverization
The reaction temperature rises, fire breaks out inside the reactor, and there is a large difference in temperature between the inlet and outlet of the reactor.
Scaling at the top of the reactor, catalyst coking, local collapse of the bed layer
Issues such as fouling at the top of the reactor, catalyst coking, and local collapse of the bed layer occur; among these, fouling at the top of the reactor leading to an increase in pressure drop is the most common one.
Excessively high reaction temperatures can cause catalyst coking; high metal content in the feed oil leads to excessive dust formation in the catalyst bed, which in turn causes blockages; water present in the feed oil can result in catalyst fragmentation; improper catalyst loading or incorrect installation of the reactor internals can all lead to an increase in pressure drop within the reaction system, large fluctuations in the amount of recycled hydrogen, or frequent use of emergency pressure relief valves
The catalyst cokes, the heating furnace tubes coke as well; the feed oil is quite sludgy
Changes in the properties of the raw materials, coking of the catalyst bed, and bed collapse
1. The crude oil contains many impurities, which leads to an increase in the pressure drop across the bed; it is recommended to install an additional filter for the crude oil. 2. If the pressure difference exceeds 0.3 MPa, the reactor should be drained and its catalyst replaced with a new one
Severe catalyst coking, excessive processing volume, changes in oil properties
Coking； Low airspeed ； Low hydrogen partial pressure