Talk:Cracking (chemistry)

Eugene Houdry, not Alex Oblad is generally credited with inventing Catalytic Cracking. See what the American Chemical Society has to say: http://acswebcontent.acs.org/landmarks/landmarks/hdr/index.html

You may also check the following reference, that was quoted by the ACS article: Alex Oblad. "The Contributions of Eugene J. Houdry to the Development of Catalytic Cracking." In Heterogenous Catalysis: Selected American Histories, ed. by Burtron H. Davis and William P. Hettinger (Washington, DC: American Chemical Society, 1983): 61-75.

1. should we bring the section on cracking mechanism from the alkane page over here?
2. need to include info on hydrocracking done --71.115.209.156 01:33, 16 Jun 2005 (UTC)
3. more details needed on process chemistry, mechanism, side reactions, thermodynamics and kinetics (would that be too much for an encyclopedia article?) --Unconcerned 10:23, 25 Feb 2004
4. should the Steam_cracking and pyrolysis pages be combined with this page? 131.203.9.226 17:13, 24 Aug 2004

::Steam cracking is what the average refiner would call pyrolysis, while pyrolysis probably refers to the more general usage of the term; so yes, I think steam cracking should be merged and a redirect left in place; while pyrolysis updated to include a link to cracking (chemistry). Would you please consider contributing with some of the things above? At this moment I do not have the necessary time to edit the 'pedia :-( --Unconcerned 03:54, 26 Aug 2004 (UTC) done --71.115.209.156 01:06, 16 Jun 2005 (UTC)

Article has a lot of very specific information, but no citations.

The primary catalytic material in modern FCC catalyst is Y-type zeolite, which is a special geometric structure composed of silicon and aluminum oxides. Other catalytic components incorporated into FCC catalysts include high surface area alumina, acidic clays and various additives that control sulfur levels in the cracked product, sometimes other additives that help promote CO oxidation during catalyst regeneration, and still others that moderate the deliterious impact of nickel and vanadium on cracked product yields.Chem engineer 19:25, 21 January 2007 (UTC)

...is this this best image we have? A Soviet unit from 1934? WTF. —Preceding unsigned comment added by 192.149.93.63 (talk) 17:20, 26 March 2008 (UTC)

Shouldn't this have some sort of protection to prevent vandalism? it is an important part of A-level science & it should be protected from vandalism J (talk) 16:33, 26 January 2010 (UTC)

Is there a link with Fractional Distillation? —Preceding unsigned comment added by 220.233.47.71 (talk) 12:18, 22 February 2010 (UTC)

This section just looks like a coroporate advert. Suggest it is removed. — Preceding unsigned comment added by 217.33.181.2 (talk) 15:26, 21 November 2011 (UTC)

Good day. I see no information here on the environmental effects of the process(es) described in the article. Can someone more knowledgeable than I add such material, specifically the air emissions and solutions/ technology to address such emissions? Also, it would be good to reference any related legislation. Thank you, Hu Gadarn (talk) 17:52, 14 June 2012 (UTC)

This article has been plagiarised by a published book:

[https://en.wikipedia.org/w/index.php?title=Cracking_(chemistry)&diff=301974987&oldid=301201183 The 14 July 2009 version] first introduced this wording:

In modern cracking furnaces, the residence time is even reduced to milliseconds, resulting in gas velocities faster than the speed of sound, to improve yield. After the cracking temperature has been reached, the gas is quickly quenched to stop the reaction in a transfer line heat exchanger.

The book "Applied Plastics Engineering Handbook: Processing and Materials" (first edition, published in 2011) contains the sentence "In modern cracking furnaces, the residence time is even reduced to milliseconds (resulting in gas velocities reaching speeds beyond the speed of sound) in order to improve yield of desired products."

{{cite book|last=Kutz|first=edited by Myer|title=Applied plastics engineering handbook : processing and materials|publisher=Elsevier/William Andrew|location=Amsterdam|isbn=9781437735147|url=http://books.google.de/books?id=urctkFROYbkC&pg=PA24&dq=catalytic+cracking+speed+of+sound&hl=en&sa=X&ei=9QuyUrO7NcaOswaOlYHYDA&redir_esc=y#v=onepage&q=catalytic%20cracking%20speed%20of%20sound&f=false|edition=1st}} p. 23 (note the predatory academic publisher ;-D ) --Slashme (talk) 21:14, 18 December 2013 (UTC)

:I put this back after it had been removed (see [https://en.wikipedia.org/w/index.php?title=Cracking_(chemistry)&diff=586768457&oldid=586737366 this revision]). Our sentence predates the publication of the book by about 2 years. It seems to me as if they plagiarised this article, not the other way around. --Slashme (talk) 10:12, 19 December 2013 (UTC)

User:JonRichfield alerted me to the question of whether steam cracking is done at supersonic gas velocities. A quick skim of [http://www.google.de/patents?hl=en&lr=&vid=USPAT7618597&id=p2HVAAAAEBAJ&oi=fnd&dq=+%22speed+of+sound%22+%22steam+cracking%22&printsec=abstract#v=onepage&q=%22speed%20of%20sound%22%20%22steam%20cracking%22&f=false this patent] gives me the impression that it does, and that they use convergent/divergent nozzles to achieve this. --Slashme (talk) 21:23, 18 December 2013 (UTC)

The section on hydrocracking is in desperate need of revision. Two major oversights caught my eye:

• That the function of hydrogen in hydrocracking is to hydrodesulfurize and hydrodenitrify; the actual function is to promote formation of heavier middle distillates and sometimes to act as a quenching gas for temperature control, and hydrogenation of inorganics for desulfurization and denitrification takes place before the actual hydrocracking process (see, e.g., http://www.eia.gov/todayinenergy/detail.cfm?id=9650).
• That the modern process of hydrocracking is related to brown coal hydrogenation to liquid fuels; this is a totally unrelated process and should be categorized with synthetic liquid fuels production.

The quality of that section of this article is also very low in comparison to the one on fluid catalytic cracking. I am not a regular wikipedia editor and do not have the time to deal with this, but I am posting this in the hopes that someone will work on that section to bring it up to the same standard as the one on FCC.-174.44.250.174 (talk) 22:18, 7 August 2014 (UTC)

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According to a chemistry textbook, thermal cracking of hydrocarbons (alkane, as the context implies) is exothermic reaction. VoidVoice (talk) 13:36, 31 July 2018 (UTC)