Editing Pyrolysis (section)

== Occurrence and uses ==

===Clandestine chemistry===
{{also|Clandestine chemistry#Pyrolysis}}

[[Conversion of CBD to THC]] can be brought about by pyrolysis.<ref>{{cite book | vauthors = Razdan RK | chapter = The Total Synthesis of Cannabinoids. | title = Total Synthesis of Natural Products | veditors = ApSimon J | publisher = John Wiley & Sons| date = January 1981 | volume = 4 | pages = 185–262 | isbn =  978-0-470-12953-1 | doi = 10.1002/9780470129678.ch2 }}</ref><ref name = "Czégény_2021">{{cite journal | vauthors = Czégény Z, Nagy G, Babinszki B, Bajtel Á, Sebestyén Z, Kiss T, Csupor-Löffler B, Tóth B, Csupor D | title = CBD, a precursor of THC in e-cigarettes | journal = Scientific Reports | volume = 11 | issue = 1 | pages = 8951 | date = April 2021 | pmid = 33903673 | pmc = 8076212 | doi = 10.1038/s41598-021-88389-z | bibcode = 2021NatSR..11.8951C }}</ref>

===Cooking===
{{multiple image
| align             = right
| width             = 
| image1            = Caramelisation of carrots.jpg
| alt1              = Brownish onions with carrots and celery in a frying pan.
| caption1          = [[Caramelizing|Caramelized]] onions are slightly pyrolyzed.
| image2            = Verkohlte Pizza 2013-04-01-2658.jpg
| alt2              = A blacked bent disc, barely recognizible as a pizza, standing up stiffly from a (fresh, white) plate
| caption2          = This pizza is pyrolyzed, almost completely carbonized.
| footer            = 
}}

Pyrolysis has many applications in food preparation.<ref name="humboldt">{{cite web |last1=Kaplan |first1=Ryan |title=Pyrolysis: Biochar, Bio-Oil and Syngas from Wastes |url=http://users.humboldt.edu/rjkaplan/project_kaplan.html |website=users.humboldt.edu |publisher=Humboldt University |access-date=19 May 2019 |format=Course notes for Environmental Resources Engineering 115 |date=Fall 2011 |archive-date=3 April 2014 |archive-url=https://web.archive.org/web/20140403184628/http://users.humboldt.edu/rjkaplan/project_kaplan.html  }}</ref> [[Caramelization]] is the pyrolysis of sugars in food (often after the sugars have been produced by the breakdown of [[polysaccharide]]s). The food goes brown and changes flavor. The distinctive flavors are used in many dishes; for instance, caramelized onion is used in [[French onion soup]].<ref name="scicook">{{cite web |title=What is Caramelization? |url=https://www.scienceofcooking.com/caramelization.htm |website=www.scienceofcooking.com |access-date=19 May 2019}}</ref><ref>{{cite web |last1=Brimm |first1=Courtney |title=Cooking with Chemistry: What is Caramelization? |url=https://commonsensescience.wordpress.com/2011/11/07/cooking-with-chemistry-what-is-caramelization/ |website=Common Sense Science |access-date=19 May 2019 |language=en |date=7 November 2011}}</ref> The temperatures needed for caramelization lie above the [[boiling point]] of water.<ref name="scicook" /> [[Frying oil]] can easily rise above the boiling point. Putting a lid on the frying pan keeps the water in, and some of it re-condenses, keeping the temperature too cool to brown for longer time.

Pyrolysis of food can also be undesirable, as in the [[charring]] of burnt food (at temperatures too low for the [[Combustion#Complete|oxidative combustion]] of carbon to produce flames and burn the food to [[ash]]).

=== Coke, carbon, charcoals, and chars ===
[[File:BurningOgatan(JapaneseBriquetteCharcoal).theora.ogv|thumb|[[Charcoal briquette]]s, often made from compressed sawdust or similar, in use.]]

Carbon and carbon-rich materials have desirable properties but are nonvolatile, even at high temperatures. Consequently, pyrolysis is used to produce many kinds of carbon; these can be used for fuel, as reagents in steelmaking (coke), and as structural materials.

[[Charcoal]] is a less smoky fuel than pyrolyzed wood.<ref>{{cite journal |last1=Sood |first1=A |title=Indoor fuel exposure and the lung in both developing and developed countries: an update. |journal=Clinics in Chest Medicine |date=December 2012 |volume=33 |issue=4 |pages=649–65 |doi=10.1016/j.ccm.2012.08.003 |pmid=23153607 |pmc=3500516 }}</ref> Some cities ban, or used to ban, wood fires; when residents only use charcoal (and similarly treated rock coal, called ''coke'') air pollution is significantly reduced. In cities where people do not generally cook or heat with fires, this is not needed. In the mid-20th century, "smokeless" legislation in Europe required cleaner-burning techniques, such as [[coke (fuel)|coke]] fuel<ref name="zones">{{cite journal |title=SMOKELESS zones. |journal=British Medical Journal |date=10 October 1953 |volume=2 |issue=4840 |pages=818–20 |doi=10.1136/bmj.2.4840.818 |pmid=13082128 |pmc=2029724 }}</ref> and smoke-burning incinerators<ref>{{Cite web|url=https://www.freepatentsonline.com/3881430.html|title=Two-stage incinerator, United States Patent 3881430 |work=www.freepatentsonline.com |access-date=11 February 2023}}</ref> as an effective measure to reduce air pollution<ref name="zones" />

[[File:Coal-forge-diagram.svg|thumb|right|upright=1.25|A blacksmith's forge, with a blower forcing air through a bed of fuel to raise the temperature of the fire. On the periphery, coal is pyrolyzed, absorbing heat; the coke at the center is almost pure carbon, and releases a lot of heat when the carbon oxidizes.]]

[[File:CoalPyrolysisProducts.png|thumb|upright=1.25|Typical organic products obtained by pyrolysis of coal (X = CH, N).]]
The coke-making or "coking" process consists of heating the material in "coking ovens" to very high temperatures (up to {{convert|900|C|F|disp=or|sigfig=2}}) so that the molecules are broken down into lighter volatile substances, which leave the vessel, and a porous but hard residue that is mostly carbon and inorganic ash. The amount of volatiles varies with the source material, but is typically 25–30% of it by weight. High temperature pyrolysis is used on an industrial scale to convert [[coal]] into [[Coke (fuel)|coke]]. This is useful in [[metallurgy]], where the higher temperatures are necessary for many processes, such as [[steelmaking]]. Volatile by-products of this process are also often useful, including [[benzene]] and [[pyridine]].<ref>{{cite encyclopedia|author=Ludwig Briesemeister |author2=Andreas Geißler |author3=Stefan Halama |author4=Stephan Herrmann |author5=Ulrich Kleinhans |author6=Markus Steibel |author7=Markus Ulbrich |author8=Alan W. Scaroni |author9=M. Rashid Khan |author10=Semih Eser |author11=Ljubisa R. Radovic |pages=1–44|chapter=Coal Pyrolysis|encyclopedia=Ullmann's Encyclopedia of Industrial Chemistry|year=2002|publisher=Wiley-VCH|place=Weinheim| doi=10.1002/14356007.a07_245.pub2|isbn=978-3-527-30673-2}}</ref>  Coke can also be produced from the solid residue left from petroleum refining.

The original [[xylem|vascular structure]] of the wood and the pores created by escaping gases combine to produce a light and porous material. By starting with a dense wood-like material, such as [[nutshell]]s or [[peach]] [[endocarp|stone]]s, one obtains a form of charcoal with particularly fine pores (and hence a much larger pore surface area), called [[activated carbon]], which is used as an [[adsorption|adsorbent]] for a wide range of chemical substances.

[[Biochar]] is the residue of incomplete organic pyrolysis, e.g., from cooking fires.  It is a key component of the [[terra preta]] soils associated with ancient [[indigenous peoples of Brazil|indigenous]] communities of the [[Amazon basin]].<ref name="lehmann1">
  {{cite web 
  | url=http://www.css.cornell.edu/faculty/lehmann/biochar/Biochar_home.htm 
  | title=Biochar: the new frontier 
  | author=Lehmann, Johannes 
  | access-date=2008-07-10 |archive-url = https://web.archive.org/web/20080618231424/http://www.css.cornell.edu/faculty/lehmann/biochar/Biochar_home.htm <!-- Bot retrieved archive --> |archive-date = 2008-06-18}}
</ref> Terra preta is much sought by local farmers for its superior fertility and capacity to promote and retain an enhanced suite of beneficial microbiota, compared to the typical red soil of the region. Efforts are underway to recreate these soils through [[biochar]], the solid residue of pyrolysis of various materials, mostly organic waste.
[[File:Carbon fibers from silk cocoon.tif|right|thumb|Carbon fibers produced by pyrolyzing a silk cocoon. Electron micrograph, scale bar at bottom left shows 100 [[Micrometre|μm]].]]
[[Carbon fiber]]s are filaments of carbon that can be used to make very strong yarns and textiles. Carbon fiber items are often produced by spinning and weaving the desired item from fibers of a suitable [[polymer]], and then pyrolyzing the material at a high temperature (from {{convert|1500|-|3000|°C|F|disp=or|sigfig=3}}).  The first carbon fibers were made from [[rayon]], but [[polyacrylonitrile]] has become the most common starting material. For their first workable [[electric lamp]]s, [[Joseph Wilson Swan]] and [[Thomas Edison]] used carbon filaments made by pyrolysis of [[cotton]] yarns and [[bamboo]] splinters, respectively.

Pyrolysis is the reaction used to coat a preformed substrate with a layer of [[pyrolytic carbon]]. This is typically done in a fluidized bed reactor heated to {{convert|1000|-|2000|°C|F|disp=or|sigfig=3}}. Pyrolytic carbon coatings are used in many applications, including [[artificial heart valve]]s.<ref name="ratner">Ratner, Buddy D. (2004). Pyrolytic carbon. In ''[https://books.google.com/books?id=Uzmrq7LO7loC&dq=discovery%20of%20pyrolytic&pg=PA171 Biomaterials science: an introduction to materials in medicine] {{webarchive|url=https://web.archive.org/web/20140626221658/http://books.google.com/books?id=Uzmrq7LO7loC&lpg=PA172&ots=zcTbDBKgU-&dq=discovery%20of%20pyrolytic&pg=PA171 |date=2014-06-26 }}''. Academic Press. pp. 171–180. {{ISBN|0-12-582463-7}}.</ref>

=== Liquid and gaseous biofuels ===
{{see also|Biofuel}}
Pyrolysis is the basis of several methods for producing fuel from [[biomass]], i.e. [[lignocellulosic biomass]].<ref>Evans, G. [http://www.nnfcc.co.uk/metadot/index.pl?id=6597;isa=DBRow;op=show;dbview_id=2457 "Liquid Transport Biofuels – Technology Status Report"] {{webarchive |url=https://web.archive.org/web/20080919135538/http://www.nnfcc.co.uk/metadot/index.pl?id=6597;isa=DBRow;op=show;dbview_id=2457 |date=September 19, 2008 }}, "[[National Non-Food Crops Centre]]", 14-04-08. Retrieved on 2009-05-05.</ref> Crops studied as biomass feedstock for pyrolysis include native North American prairie grasses such as [[Panicum virgatum|''switchgrass'']] and bred versions of other grasses such as [[Miscanthus giganteus|''Miscantheus giganteus'']]. Other sources of [[organic matter]] as feedstock for pyrolysis include greenwaste, sawdust, waste wood, leaves, vegetables, nut shells, straw, cotton trash, rice hulls, and orange peels.<ref name="Zhou-2013" /> Animal waste including poultry litter, dairy manure, and potentially other manures are also under evaluation. Some industrial byproducts are also suitable feedstock including paper sludge, distillers grain,<ref name="bestEnergiesBestPyrol">{{cite web
 |title       = Biomass Feedstock for Slow Pyrolysis
 |work        = BEST Pyrolysis, Inc. website
 |publisher   = BEST Energies, Inc.
 |url         = http://www.bestenergies.com/companies/bestpyrolysis.html
 |access-date  = 2010-07-30
 |url-status     = live
 |archive-url  = https://web.archive.org/web/20120102071009/http://www.bestenergies.com/companies/bestpyrolysis.html
 |archive-date = 2012-01-02
}}
</ref> and sewage sludge.<ref name="Zhao-2019">{{cite journal |last1=Zhao |first1=Ming |last2=Wang |first2=Fan |last3=Fan |first3=Yiran |last4=Raheem |first4=Abdul |last5=Zhou |first5=Hui |title=Low-temperature alkaline pyrolysis of sewage sludge for enhanced H2 production with in-situ carbon capture |journal=International Journal of Hydrogen Energy |date=March 2019 |volume=44 |issue=16 |pages=8020–8027 |doi=10.1016/j.ijhydene.2019.02.040 }}</ref>

In the biomass components, the pyrolysis of hemicellulose happens between 210 and 310&nbsp;°C.<ref name="Zhou-2013" /> The pyrolysis of cellulose starts from 300 to 315&nbsp;°C and ends at 360–380&nbsp;°C, with a peak at 342–354&nbsp;°C.<ref name="Zhou-2013" /> Lignin starts to decompose at about 200&nbsp;°C and continues until 1000&nbsp;°C.<ref name="Zhou-2015-2">{{cite journal |last1=Zhou |first1=Hui |last2=Long |first2=Yanqiu |last3=Meng |first3=Aihong |last4=Chen |first4=Shen |last5=Li |first5=Qinghai |last6=Zhang |first6=Yanguo |title=A novel method for kinetics analysis of pyrolysis of hemicellulose, cellulose, and lignin in TGA and macro-TGA |journal=RSC Advances |date=2015 |volume=5 |issue=34 |pages=26509–26516 |doi=10.1039/C5RA02715B |bibcode=2015RSCAd...526509Z }}</ref>

Synthetic [[diesel fuel]] by pyrolysis of organic materials is not yet economically competitive.<ref name="us_doe">
  {{cite web 
  | url=http://www1.eere.energy.gov/biomass/pyrolysis.html 
  | publisher=US DOE 
  | title=Pyrolysis and Other Thermal Processing
  | archive-url=https://web.archive.org/web/20070814144750/http://www1.eere.energy.gov/biomass/pyrolysis.html 
  | archive-date=2007-08-14}}
</ref>  Higher efficiency is sometimes achieved by '''flash pyrolysis''', in which finely divided feedstock is quickly heated to between {{convert|350|and|500|°C|F|sigfig=2}} for less than two seconds.

[[Syngas]] is usually produced by pyrolysis.<ref name="humboldt" />

The low quality of oils produced through pyrolysis can be improved by physical and chemical processes,<ref>{{cite journal|last1=Ramirez|first1=Jerome|last2=Brown|first2=Richard|last3=Rainey|first3=Thomas|title=A Review of Hydrothermal Liquefaction Bio-Crude Properties and Prospects for Upgrading to Transportation Fuels|journal=Energies|date=1 July 2015|volume=8|issue=7|pages=6765–6794|doi=10.3390/en8076765|doi-access=free}}</ref> which might drive up production costs, but may make sense economically as circumstances change.

There is also the possibility of integrating with other processes such as [[mechanical biological treatment]] and [[anaerobic digestion]].<ref>Marshall, A. T. & Morris, J. M. (2006) [http://www.alexmarshall.me.uk/index_files/documents/CIWM.pdf A Watery Solution and Sustainable Energy Parks] {{webarchive|url=https://web.archive.org/web/20070928070845/http://www.alexmarshall.me.uk/index_files/documents/CIWM.pdf |date=2007-09-28 }}, [[Chartered Institute of Wastes Management|CIWM]] Journal, pp. 22–23</ref>  Fast pyrolysis is also investigated for biomass conversion.<ref name="Westerhof">
  {{cite thesis
 |author      = Westerhof, Roel Johannes Maria
 |title       = Refining fast pyrolysis of biomass
 |date        = 2011
 |publisher   = University of Twente
 |url         = http://doc.utwente.nl/78777/
 |work        = Thermo-Chemical Conversion of Biomass
 |access-date  = 2012-05-30
 |url-status     = live
 |archive-url  = https://web.archive.org/web/20130617144633/http://doc.utwente.nl/78777/
 |archive-date = 2013-06-17
}}
</ref>  Fuel bio-oil can also be produced by [[hydrous pyrolysis]].

===Methane pyrolysis for hydrogen===
[[File:Methane Pyrolysis-1.png|thumb|upright=1.35|Illustrating inputs and outputs of methane pyrolysis, an efficient one-step process to produce Hydrogen and no greenhouse gas]]
Methane pyrolysis<ref>{{cite journal |last1=Upham |first1=D. Chester |last2=Agarwal |first2=Vishal |last3=Khechfe |first3=Alexander |last4=Snodgrass |first4=Zachary R. |last5=Gordon |first5=Michael J. |last6=Metiu |first6=Horia |last7=McFarland |first7=Eric W. |title=Catalytic molten metals for the direct conversion of methane to hydrogen and separable carbon |journal=Science |date=17 November 2017 |volume=358 |issue=6365 |pages=917–921 |doi=10.1126/science.aao5023 |pmid=29146810 |doi-access=free |bibcode=2017Sci...358..917U }}</ref> is an industrial process for "turquoise" [[hydrogen production]] from [[methane]] by removing solid [[carbon]] from [[natural gas]].<ref>{{cite journal |last1=Timmerberg |first1=Sebastian |last2=Kaltschmitt |first2=Martin |last3=Finkbeiner |first3=Matthias |title=Hydrogen and hydrogen-derived fuels through methane decomposition of natural gas – GHG emissions and costs |journal=Energy Conversion and Management: X |date=September 2020 |volume=7 |pages=100043 |doi=10.1016/j.ecmx.2020.100043 |doi-access=free |bibcode=2020ECMX....700043T |hdl=11420/6245 |hdl-access=free }}</ref> This one-step process produces hydrogen in high volume at low cost (less than [[steam reforming]] with [[carbon sequestration]]).<ref>
{{cite thesis |last1=Lumbers |first1=Brock |title=Mathematical Modelling and Simulation of Catalyst Deactivation for the Continuous Thermo-Catalytic Decomposition of Methane.|url=https://opus4.kobv.de/opus4-rhein-waal/frontdoor/index/index/docId/775 |date=20 August 2020 |pages=12–13 |publisher=Rhine-Waal University of Applied Sciences |access-date=16 March 2022}}</ref> No greenhouse gas is released. No deep well injection of carbon dioxide is needed. Only water is released when hydrogen is used as the fuel for [[fuel-cell]] electric heavy truck transportation,
<ref>{{cite web |last1=Fialka |first1=John |title=Energy Department Looks to Boost Hydrogen Fuel for Big Trucks |url=https://www.scientificamerican.com/article/energy-department-looks-to-boost-hydrogen-fuel-for-big-trucks/ |website=E&E News |publisher=Scientific American |access-date=7 November 2020}}</ref><ref>
{{cite web |last1=CCJ News
 |title=How fuel cell trucks produce electric power and how they're fueled |url=https://www.ccjdigital.com/hydrogen-powered-class-8-rigs-electric-refuel/ |website=CCJ News |date=13 August 2020 |publisher=Commercial Carrier Journal |access-date=19 October 2020}}</ref><ref>
{{cite web |last1=Toyota
 |title=Hydrogen Fuel-Cell Class 8 Truck |url=https://global.toyota/en/newsroom/corporate/34009225.html |website=Hydrogen-Powered Truck Will Offer Heavy-Duty Capability and Clean Emissions |publisher=Toyota |access-date=19 October 2020}}</ref><ref>
{{cite news |last1=Colias |first1=Mike
 |title=Auto Makers Shift Their Hydrogen Focus to Big Rigs |url=https://www.wsj.com/articles/auto-makers-shift-their-hydrogen-focus-to-big-rigs-11603714573 |newspaper=The Wall Street Journal |date=26 October 2020
 |access-date=26 October 2020}}</ref><ref>
{{cite web |last1=Honda
 |title=Honda Fuel-Cell Clarity |url=https://automobiles.honda.com/clarity-fuel-cell |website=Clarity Fuel Cell |publisher=Honda |access-date=19 October 2020}}
</ref> gas turbine electric power generation,<ref>
{{cite web |last1=GE Turbines
 |title=Hydrogen fueled power turbines |url=https://www.ge.com/power/gas/fuel-capability/hydrogen-fueled-gas-turbines |website=Hydrogen fueled gas turbines |publisher=General Electric |access-date=19 October 2020}}</ref><ref>{{cite web |last1=Solar Turbines |title=Hydrogen fueled power turbines |url=https://www.solarturbines.com/en_US/solutions/carbon-reduction/carbon-neutral-fuels/hydrogen.html |website=Power From Hydrogen Gas For Carbon Reduction |publisher=Solar Turbines |access-date=19 October 2020 |archive-date=9 August 2020 |archive-url=https://web.archive.org/web/20200809111252/https://www.solarturbines.com/en_US/solutions/carbon-reduction/carbon-neutral-fuels/hydrogen.html |url-status=dead }}</ref> and hydrogen for industrial processes including producing ammonia fertilizer and cement.<ref>
{{cite web |last1=Crolius |first1=Stephen H.
 |title=Methane to Ammonia via Pyrolysis |url=https://www.ammoniaenergy.org/articles/methane-to-ammonia-via-pyrolysis/ |website=Ammonia Energy Association |date=27 January 2017
 |access-date=19 October 2020}}
</ref><ref>
{{cite web |last1=Pérez |first1=Jorge |title=CEMEX successfully deploys hydrogen-based ground-breaking cement manufacturing technology |url=https://www.cemex.com/-/cemex-successfully-deploys-hydrogen-based-ground-breaking-technology |website=www.cemex.com |publisher=CEMEX, S.A.B. de C.V. |access-date=4 April 2021}}</ref> Methane pyrolysis is the process operating around 1065&nbsp;°C for producing [[hydrogen]] from natural gas that allows removal of carbon easily (solid carbon is a byproduct of the process).<ref>
{{cite web |last1=Cartwright |first1=Jon
 |title=The reaction that would give us clean fossil fuels forever |url=http://www.newscientist.com/article/mg23230940-200-crack-methane-for-fossil-fuels-without-tears |website=NewScientist |publisher=New Scientist Ltd. |access-date=30 October 2020}}</ref><ref>
{{cite web |last1=Karlsruhe Institute of Technology
 |title=Hydrogen from methane without CO2 emissions |url=https://phys.org/news/2013-04-hydrogen-methane-co2-emissions.html |website=Phys.Org |access-date=30 October 2020}}
</ref> The industrial quality solid carbon can then be sold or landfilled and is not released into the atmosphere, avoiding emission of greenhouse gas (GHG) or ground water pollution from a landfill. 

In 2015, a company called Monolith Materials built a pilot plant in Redwood City, CA to study scaling Methane Pyrolysis using renewable power in the process.<ref>{{Cite web|date=2019-05-28|title=Successful Demonstration Program Underpins Monolith Materials' Commercialization Plans - Zeton|url=https://www.zeton.com/news/successful-demonstration-program-underpins-monolith-materials-commercialization-plans/|access-date=2022-01-05|website=Zeton Inc|language=en-US}}</ref> A successful pilot project then led to a larger commercial-scale demonstration plant in Hallam, Nebraska in 2016.<ref>{{Cite web|title=Monolith|url=https://monolith-corp.com/monolith-story|access-date=2022-01-05|website=monolith-corp.com|language=en}}</ref> As of 2020, this plant is operational and can produce around 14 metric tons of hydrogen per day.&nbsp; In 2021, the US Department of Energy backed Monolith Materials' plans for major expansion with a $1B loan guarantee.<ref>{{Cite web|title=DOE backs Neb. hydrogen, carbon black project with $1B loan guarantee|url=https://www.spglobal.com/marketintelligence/en/news-insights/latest-news-headlines/doe-backs-neb-hydrogen-carbon-black-project-with-1b-loan-guarantee-68193136|access-date=2022-01-05|website=www.spglobal.com|language=en-us}}</ref> The funding will help produce a plant capable of generating 164 metric tons of hydrogen per day by 2024.  Pilots with gas utilities and [[biogas]] plants are underway with companies like Modern Hydrogen.<ref>{{Cite news |date=2022-07-27 |title=NW Natural to Partner with Modern Electron on Exciting Pilot Project to Turn Methane into Clean Hydrogen and Solid Carbon |language=en-US |work=The Wall Street Journal |url=https://www.wsj.com/articles/nw-natural-to-partner-with-modern-electron-on-exciting-pilot-project-to-turn-methane-into-clean-hydrogen-and-solid-carbon-01658966165 |access-date=2022-08-24 }}</ref><ref>{{Cite web |last=Stiffler |first=Lisa |date=2022-04-26 |title=Cut the BS: This startup is converting cow manure into clean-burning hydrogen fuel |url=https://www.geekwire.com/2022/cut-the-bs-this-startup-is-converting-cow-manure-into-clean-burning-hydrogen-fuel/ |access-date=2022-08-24 |website=GeekWire |language=en-US}}</ref>  Volume production is also being evaluated in the BASF "methane pyrolysis at scale" pilot plant,<ref name="auto1"/> the chemical engineering team at University of California - Santa Barbara<ref>{{cite press release |last1=Fernandez |first1=Sonia |title=Researchers develop potentially low-cost, low-emissions technology that can convert methane without forming CO2 |url=https://phys.org/news/2017-11-potentially-low-cost-low-emissions-technology-methane.html |work=phys.org |publisher=University of California - Santa Barbara |date=21 November 2017 }}</ref> and in such research laboratories as Karlsruhe Liquid-metal Laboratory (KALLA).<ref>
{{cite web |last1=Gusev |first1=Alexander
 |title=KITT/IASS - Producing CO2 Free Hydrogen From Natural Gas For Energy Usage |url=http://www.europeanenergyinnovation.eu/Latest-Research/Spring-2019/KITT-IASS-Producing-CO2-free-hydrogen-from-natural-gas-for-energy-usage |website=European Energy Innovation |publisher=Institute for Advanced Sustainability Studies |access-date=30 October 2020}}
</ref>  Power for process heat consumed is only one-seventh of the power consumed in the water electrolysis method for producing hydrogen.<ref>{{cite web |date=December 2020 |title=Methane pyrolysis process uses renewable electricity split CH4 into H2 and carbon-black |url=https://www.chemengonline.com/methane-pyrolysis-process-uses-renewable-electricity-split-ch4-h2-carbon-black/?printmode=1 |access-date=17 December 2020}}</ref>

The Australian company Hazer Group was founded in 2010 to commercialise technology originally developed at the University of Western Australia.&nbsp; The company was listed on the ASX in December 2015. It is completing a commercial demonstration project to produce renewable hydrogen and graphite from wastewater and iron ore as a process catalyst use technology created by the University of Western Australia (UWA). The Commercial Demonstration Plant project is an Australian first, and expected to produce around 100 tonnes of fuel-grade hydrogen and 380 tonnes of graphite each year starting in 2023.{{fact|date=March 2025}} It was scheduled to commence in 2022. "10 December 2021: Hazer Group (ASX: HZR) regret to advise that there has been a delay to the completion of the fabrication of the reactor for the Hazer Commercial Demonstration Project (CDP). This is expected to delay the planned commissioning of the Hazer CDP, with commissioning now expected to occur after our current target date of 1Q 2022."<ref>{{cite press release |date=10 December 2021 |title=Delay to Reactor Fabrication |url=https://cdn-api.markitdigital.com/apiman-gateway/ASX/asx-research/1.0/file/2924-02465184-6A1068033?access_token=83ff96335c2d45a094df02a206a39ff4 |publisher=Hazer Group }}</ref> The Hazer Group has collaboration agreements with Engie for a facility in France in May 2023,<ref>{{cite press release |title=Hazer advances ENGIE collaboration for facility in France |url=https://hazergroup.com.au/announcement/hazer-advances-engie-collaboration-for-facility-in-france/ |publisher=Hazer Group }}</ref> A Memorandum of Understanding with Chubu Electric & Chiyoda in Japan April 2023<ref>{{cite press release |title=Hazer Signs MOU with Chubu Electric & Chiyoda |url=https://hazergroup.com.au/announcement/hazer-signs-mou-with-chubu-electric-chiyoda/ |publisher=Hazer Group }}</ref> and an agreement with Suncor Energy and FortisBC to develop 2,500 tonnes per Annum Burrard-Hazer Hydrogen Production Plant in Canada April 2022<ref>{{Cite web |title=Hazer Group – Investor Presentation {{!}} hazergroup.com.au |url=https://hazergroup.com.au/announcement/hazer-group-investor-presentation/ |access-date=2023-05-23 |language=en-AU}}{{psc|date=March 2025}}</ref><ref>{{Cite web |title=Burrard Hazer Hydrogen Project Announcement {{!}} hazergroup.com.au |url=https://hazergroup.com.au/announcement/burrard-hazer-hydrogen-project-announcement/ |access-date=2023-05-23 |language=en-AU}}{{psc|date=March 2025}}</ref>

The American company C-Zero's technology converts natural gas into hydrogen and solid carbon. The hydrogen provides clean, low-cost energy on demand, while the carbon can be permanently sequestered.<ref>{{Cite web |title=C-Zero {{!}} Decarbonizing Natural Gas |url=https://www.czero.energy/ |access-date=2023-05-23 |website=C-Zero |language=en}}</ref> C-Zero announced in June 2022 that it closed a $34 million financing round led by SK Gas, a subsidiary of South Korea's second-largest conglomerate, the SK Group. SK Gas was joined by two other new investors, Engie New Ventures and Trafigura, one of the world's largest physical commodities trading companies, in addition to participation from existing investors including Breakthrough Energy Ventures, Eni Next, Mitsubishi Heavy Industries, and AP Ventures. Funding was for C-Zero's first pilot plant, which was expected to be online in Q1 2023. The plant may be capable of producing up to 400&nbsp;kg of hydrogen per day from natural gas with no CO2 emissions.<ref>{{Cite web |date=2022-06-16 |title=C-Zero Closes $34 Million Financing Round Led by SK Gas to Build Natural Gas Decarbonization Pilot |url=https://www.czero.energy/post/c-zero-closes-34-million-financing-round-led-by-sk-gas-to-build-natural-gas-decarbonization-pilot |access-date=2023-05-23 |website=C-Zero |language=en}}</ref>
 
One of the world's largest chemical companies, [[BASF]], has been researching hydrogen pyrolysis for more than 10 years.<ref>{{Cite web |title=Interview Andreas Bode |url=https://www.basf.com/au/en/who-we-are/sustainability/we-produce-safely-and-efficiently/energy-and-climate-protection/carbon-management/interview-andreas-bode.html |access-date=2023-05-23 |website=www.basf.com |language=en-AU}}</ref>

===Ethylene===
Pyrolysis is used to produce [[ethylene]], the chemical compound produced on the largest scale industrially (>110 million tons/year in 2005). In this process, hydrocarbons from petroleum are heated to around {{convert|600|C|F}} in the presence of steam; this is called [[steam cracking]]. The resulting ethylene is used to make antifreeze ([[ethylene glycol]]), PVC (via [[vinyl chloride]]), and many other polymers, such as polyethylene and polystyrene.<ref name="UllmannEthylene">{{cite book |doi=10.1002/14356007.a10_045.pub3 |chapter=Ethylene |title=Ullmann's Encyclopedia of Industrial Chemistry |date=2009 |last1=Zimmermann |first1=Heinz |last2=Walzl |first2=Roland |isbn=978-3-527-30673-2 }}</ref>

=== Semiconductors ===
[[File:MOCVD process.svg|thumb|300px|Illustration of the [[metalorganic vapour phase epitaxy]] process, which entails pyrolysis of volatiles]]
The process of [[metalorganic vapour-phase epitaxy]] (MOCVD) entails pyrolysis of volatile organometallic compounds to give semiconductors, hard coatings, and other applicable materials. The reactions entail thermal degradation of precursors, with deposition of the inorganic component and release of the hydrocarbons as gaseous waste. Since it is an atom-by-atom deposition, these atoms organize themselves into crystals to form the bulk semiconductor. Raw polycrystalline silicon is produced by the chemical vapor deposition of silane gases:
:{{chem2|SiH4  →  Si  +  2 H2}}
[[Gallium arsenide]], another semiconductor, forms upon co-pyrolysis of [[trimethylgallium]] and [[arsine]].

=== Waste management===
{{See also|Thermal depolymerization}}
Pyrolysis can also be used to treat municipal solid waste and [[plastic waste]].<ref name="Zhou-2017" /><ref name="Zhou-2015" /><ref name="Zhou-2015-3">{{Cite journal|last1=Zhou|first1=Hui|last2=Long|first2=YanQiu|last3=Meng|first3=AiHong|last4=Li|first4=QingHai|last5=Zhang|first5=YanGuo|date=January 2015|title=Interactions of three municipal solid waste components during co-pyrolysis|journal=Journal of Analytical and Applied Pyrolysis|language=en|volume=111|pages=265–271|doi=10.1016/j.jaap.2014.08.017|bibcode=2015JAAP..111..265Z }}</ref>  The main advantage is the reduction in volume of the waste. In principle, pyrolysis will regenerate the monomers (precursors) to the polymers that are treated, but in practice the process is neither a clean nor an economically competitive source of monomers.<ref>{{cite encyclopedia |first1=Walter |last1=Kaminsky |chapter=Plastics, Recycling |encyclopedia=Ullmann's Encyclopedia of Industrial Chemistry |publisher=Wiley-VCH |location=Weinheim |year=2000 |doi=10.1002/14356007.a21_057|isbn=978-3-527-30673-2 }}</ref><ref>N.J. Themelis et al. [http://www.seas.columbia.edu/earth/wtert/sofos/ACC_Final_Report_August23_2011.pdf "Energy and Economic Value of Nonrecyclable Plastics and Municipal Solid Wastes that are Currently Landfilled in the Fifty States" Columbia University Earth Engineering Center] {{webarchive|url=https://web.archive.org/web/20140508231827/http://www.seas.columbia.edu/earth/wtert/sofos/ACC_Final_Report_August23_2011.pdf |date=2014-05-08 }}</ref><ref>{{cite web |url=http://www.alternativesjournal.ca/science-and-solutions/plastic-oil |title=The Plastic to Oil Machine, A\J – Canada's Environmental Voice |work=Alternativesjournal.ca |date=2016-12-07 |access-date=2016-12-16 |archive-date=2015-09-09 |archive-url=https://web.archive.org/web/20150909064711/http://www.alternativesjournal.ca/science-and-solutions/plastic-oil  }}</ref>

In tire waste management, [[Tire recycling#Tire pyrolysis|tire pyrolysis]] is a well-developed technology.<ref name="jid">ผศ.ดร.ศิริรัตน์ จิตการค้า, "ไพโรไลซิสยางรถยนต์หมดสภาพ : กลไกการผลิตน้ำมันเชื้อเพลิงคุณภาพสูง"วิทยาลัยปิโตรเลียมและปิโตรเคมี จุฬาลงกรณ์มหาวิทยาลัย (in Thai) Jidgarnka, S. [http://www.vcharkarn.com/varticle/408 "Pyrolysis of Expired Car Tires: Mechanics of Producing High Quality Fuels"] {{webarchive|url=https://web.archive.org/web/20150220073033/http://www.vcharkarn.com/varticle/408 |date=2015-02-20 }}. Chulalongkorn University Department of Petrochemistry</ref>
Other products from car tire pyrolysis include steel wires, [[carbon black]] and bitumen.<ref>{{cite journal|author1=Roy, C. |author2=Chaala, A. |author3=Darmstadt, H. |title=The vacuum pyrolysis of used tires|journal=Journal of Analytical and Applied Pyrolysis|volume=51|issue=1–2 |pages=201–221|doi=10.1016/S0165-2370(99)00017-0|year=1999}}</ref> The area faces legislative, economic, and marketing obstacles.<ref name="j.rser.2013.02.038">{{cite journal |last1=Martínez |first1=Juan Daniel |last2=Puy |first2=Neus |last3=Murillo |first3=Ramón |last4=García |first4=Tomás |last5=Navarro |first5=María Victoria |last6=Mastral |first6=Ana Maria |title=Waste tyre pyrolysis – A review |journal=Renewable and Sustainable Energy Reviews |date=July 2013 |volume=23 |pages=179–213 |doi=10.1016/j.rser.2013.02.038 |bibcode=2013RSERv..23..179M }}</ref> Oil derived from tire rubber pyrolysis has a high sulfur content, which gives it high potential as a pollutant; consequently it should be desulfurized.<ref>{{cite journal |last1=Choi |first1=Gyung-Goo |last2=Jung |first2=Su-Hwa |last3=Oh |first3=Seung-Jin |last4=Kim |first4=Joo-Sik |title=Total utilization of waste tire rubber through pyrolysis to obtain oils and CO2 activation of pyrolysis char |journal=Fuel Processing Technology |date=July 2014 |volume=123 |pages=57–64 |doi=10.1016/j.fuproc.2014.02.007 }}</ref><ref>{{cite report |doi=10.2172/894989 |osti=894989 |title=Large-Scale Pyrolysis Oil Production: A Technology Assessment and Economic Analysis |date=2006 |last1=Ringer |first1=M. |last2=Putsche |first2=V. |last3=Scahill |first3=J. |url=https://digital.library.unt.edu/ark:/67531/metadc888262/ }}</ref>

Alkaline pyrolysis of sewage sludge at low temperature of 500&nbsp;°C can enhance {{chem|H|2}} production with in-situ carbon capture. The use of NaOH (sodium hydroxide) has the potential to produce {{chem|H|2}}-rich gas that can be used for fuels cells directly.<ref name="Zhao-2019" /><ref name="Zhao-2020" />

In early November 2021, the U.S. State of [[Georgia (U.S. state)|Georgia]] announced a joint effort with Igneo Technologies to build an $85 million large electronics recycling plant in the [[Port of Savannah]]. The project will focus on lower-value, plastics-heavy devices in the waste stream using multiple shredders and furnaces using pyrolysis technology.<ref>{{cite news |last=Leif |first=Dan |url=https://resource-recycling.com/recycling/2021/11/02/igneo-targets-low-grade-scrap-electronics-with-85m-plant/ |title=Igneo targets low-grade scrap electronics with $85M plant |work=resource-recycling.com |date=2021-11-03 |access-date=2021-11-28 }}</ref>

Waste from pyrolysis itself can also be used for useful products. For example, contaminant-rich retentate from liquid-fed pyrolysis of postconsumer multilayer packaging waste can be used as novel building composite materials, which have higher compression strengths (10-12 MPa) than construction bricks and brickworks (7 MPa), as well as 57% lower density, 0.77 g/cm<sup>3</sup> .<ref>{{cite journal |last1=Romani |first1=Alessia |last2=Kulas |first2=Daniel |last3=Curro |first3=Joseph |last4=Shonnard |first4=David R. |last5=Pearce |first5=Joshua M. |date=May 2025 |title=Recycled filtered contaminants from liquid-fed pyrolysis as novel building composite material |journal=Journal of Building Engineering |volume=102 |pages=112025 |doi=10.1016/j.jobe.2025.112025|doi-access=free }}</ref>

==== One-stepwise pyrolysis and Two-stepwise pyrolysis for Tobacco Waste ====
Pyrolysis has also been used for trying to mitigate tobacco waste. One method was done where tobacco waste was separated into two categories TLW (Tobacco Leaf Waste) and TSW (Tobacco Stick Waste). TLW was determined to be any waste from cigarettes and TSW was determined to be any waste from electronic cigarettes.  Both TLW and TSW were dried at 80&nbsp;°C for 24 hours and stored in a desiccator.<ref name="Lee-2021">{{cite journal |last1=Lee |first1=Taewoo |last2=Jung |first2=Sungyup |last3=Lin |first3=Kun-Yi Andrew |last4=Tsang |first4=Yiu Fai |last5=Kwon |first5=Eilhann E. |title=Mitigation of harmful chemical formation from pyrolysis of tobacco waste using CO2 |journal=Journal of Hazardous Materials |date=January 2021 |volume=401 |pages=123416 |doi=10.1016/j.jhazmat.2020.123416 |pmid=32763706 }}</ref> Samples were grounded so that the contents were uniform. Tobacco Waste (TW) also contains inorganic (metal) contents, which was determined using an inductively coupled plasma-optical spectrometer.<ref name="Lee-2021" /> [[Thermogravimetric analysis|Thermo-gravimetric analysis]] was used to thermally degrade four samples (TLW, TSW, [[glycerol]], and [[guar gum]]) and monitored under specific dynamic temperature conditions.<ref name="Lee-2021" /> About one gram of both TLW and TSW were used in the pyrolysis tests. During these analysis tests, {{chem|C|O|2}} and {{chem|N|2}} were used as atmospheres inside of a tubular reactor that was built using quartz tubing. For both [[Carbon dioxide|{{chem|C|O|2}}]] and {{chem|N|2}} atmospheres the flow rate was 100 mL min<sup>−1</sup>.<ref name="Lee-2021" /> External heating was created via a tubular furnace. The pyrogenic products were classified into three phases. The first phase was [[biochar]], a solid residue produced by the reactor at 650&nbsp;°C. The second phase liquid [[hydrocarbon]]s were collected by a cold solvent trap and sorted by using chromatography. The third and final phase was analyzed using an online micro GC unit and those pyrolysates were gases.

Two different types of experiments were conducted: one-stepwise pyrolysis and two-stepwise pyrolysis. One-stepwise pyrolysis consisted of a constant heating rate (10&nbsp;°C min<sup>−1</sup>) from 30 to 720&nbsp;°C.<ref name="Lee-2021" /> In the second step of the two-stepwise pyrolysis test the pyrolysates from the one-stepwise pyrolysis were pyrolyzed in the second heating zone which was controlled isothermally at 650&nbsp;°C.<ref name="Lee-2021" /> The two-stepwise pyrolysis was used to focus primarily on how well {{chem|C|O|2}} affects carbon redistribution when adding heat through the second heating zone.<ref name="Lee-2021" />

First noted was the thermolytic behaviors of TLW and TSW in both the {{chem|C|O|2}} and {{chem|N|2}} environments. For both TLW and TSW the thermolytic behaviors were identical at less than or equal to 660&nbsp;°C in the {{chem|C|O|2}} and {{chem|N|2}} environments. The differences between the environments start to occur when temperatures increase above 660&nbsp;°C and the residual mass percentages significantly decrease in the {{chem|C|O|2}} environment compared to that in the {{chem|N|2}} environment.<ref name="Lee-2021" /> This observation is likely due to the [[Boudouard reaction|Boudouard]] reaction, where we see spontaneous gasification happening when temperatures exceed 710&nbsp;°C.<ref>{{cite journal |last1=Lahijani |first1=Pooya |last2=Zainal |first2=Zainal Alimuddin |last3=Mohammadi |first3=Maedeh |last4=Mohamed |first4=Abdul Rahman |title=Conversion of the greenhouse gas {{chem|C|O|2}} to the fuel gas {{chem|C|O}} via the Boudouard reaction: A review |journal=Renewable and Sustainable Energy Reviews |date=January 2015 |volume=41 |pages=615–632 |doi=10.1016/j.rser.2014.08.034 }}</ref><ref>{{cite journal |last1=Hunt |first1=Jacob |last2=Ferrari |first2=Anthony |last3=Lita |first3=Adrian |last4=Crosswhite |first4=Mark |last5=Ashley |first5=Bridgett |last6=Stiegman |first6=A. E. |title=Microwave-Specific Enhancement of the Carbon–Carbon Dioxide (Boudouard) Reaction |journal=The Journal of Physical Chemistry C |date=27 December 2013 |volume=117 |issue=51 |pages=26871–26880 |doi=10.1021/jp4076965 }}</ref> Although these observations were seen at temperatures lower than 710&nbsp;°C it is most likely due to the catalytic capabilities of inorganics in TLW.<ref name="Lee-2021" /> It was further investigated by doing [[Inductively coupled plasma atomic emission spectroscopy|ICP-OES]] measurements and found that a fifth of the residual mass percentage was Ca species. {{chem|Ca|C|O|3}} is used in cigarette papers and filter material, leading to the explanation that degradation of [[Calcium carbonate|{{chem|Ca|C|O|3}}]] causes pure {{chem|C|O|2}} reacting with [[Calcium oxide|CaO]] in a dynamic equilibrium state.<ref name="Lee-2021" /> This being the reason for seeing mass decay between 660&nbsp;°C and 710&nbsp;°C. Differences in differential thermogram (DTG) peaks for TLW were compared to TSW. TLW had four distinctive peaks at 87, 195, 265, and 306&nbsp;°C whereas TSW had two major drop offs at 200 and 306&nbsp;°C with one spike in between.<ref name="Lee-2021" /> The four peaks indicated that TLW contains more diverse types of additives than TSW.<ref name="Lee-2021" /> The residual mass percentage between TLW and TSW was further compared, where the residual mass in TSW was less than that of TLW for both {{chem|C|O|2}} and {{chem|N|2}} environments concluding that TSW has higher quantities of additives than TLW.&nbsp;
[[File:Pyrolysis.svg|thumb|Production of Hydrogen, Methane, and Tars when creating Biochar]]

The one-stepwise pyrolysis experiment showed different results for the {{chem|C|O|2}} and {{chem|N|2}} environments. During this process the evolution of 5 different notable gases were observed. Hydrogen, Methane, Ethane, Carbon Dioxide, and Ethylene all are produced when the thermolytic rate of TLW began to be retarded at greater than or equal to 500&nbsp;°C. Thermolytic rate begins at the same temperatures for both the {{chem|C|O|2}} and {{chem|N|2}} environment but there is higher concentration of the production of Hydrogen, Ethane, Ethylene, and Methane in the {{chem|N|2}} environment than that in the {{chem|C|O|2}} environment. The concentration of CO in the {{chem|C|O|2}} environment is significantly greater as temperatures increase past 600&nbsp;°C and this is due to {{chem|C|O|2}} being liberated from {{chem|Ca|C|O|3}} in TLW.<ref name="Lee-2021" /> This significant increase in CO concentration is why there is lower concentrations of other gases produced in the {{chem|C|O|2}} environment due to a dilution effect.<ref name="Lee-2021" /> Since pyrolysis is the re-distribution of carbons in carbon substrates into three pyrogenic products.<ref name="Lee-2021" /> The {{chem|C|O|2}} environment is going to be more effective because the {{chem|C|O|2}} reduction into CO allows for the oxidation of pyrolysates to form CO. In conclusion the {{chem|C|O|2}} environment allows a higher yield of gases than oil and biochar. When the same process is done for TSW the trends are almost identical therefore the same explanations can be applied to the pyrolysis of TSW.<ref name="Lee-2021" />

Harmful chemicals were reduced in the {{chem|C|O|2}} environment due to CO formation causing tar to be reduced. One-stepwise pyrolysis was not that effective on activating {{chem|C|O|2}} on carbon rearrangement due to the high quantities of liquid pyrolysates (tar). Two-stepwise pyrolysis for the {{chem|C|O|2}} environment allowed for greater concentrations of gases due to the second heating zone. The second heating zone was at a consistent temperature of 650&nbsp;°C isothermally.<ref name="Lee-2021" /> More reactions between {{chem|C|O|2}} and gaseous pyrolysates with longer residence time meant that {{chem|C|O|2}} could further convert pyrolysates into CO.<ref name="Lee-2021" /> The results showed that the two-stepwise pyrolysis was an effective way to decrease tar content and increase gas concentration by about 10 wt.% for both TLW (64.20 wt.%) and TSW (73.71%).<ref name="Lee-2021" />

=== Thermal cleaning ===
{{See also|Thermal cleaning}}
Pyrolysis is also used for ''thermal cleaning'', an industrial application to remove [[Organic chemistry|organic]] substances such as [[polymer]]s, [[plastic]]s and [[coating]]s from parts, products or production components like [[Plastics extrusion|extruder screws]], [[Spinneret (polymers)|spinnerets]]<ref>{{cite web |url=http://www.fiberjournal.com/back-issues/ |title=Effective Spinneret Cleaning |author=Heffungs, Udo |date=June 2010 |publisher=Fiber Journal |access-date=19 April 2016 |url-status=live |archive-url=https://web.archive.org/web/20160630015337/http://www.fiberjournal.com/back-issues/ |archive-date=30 June 2016 }}</ref> and [[static mixer]]s. During the thermal cleaning process, at temperatures from {{convert|310|to|540|C|sigfig=1}},<ref name="Mainord1994">{{cite web |url=http://infohouse.p2ric.org/ref/02/01800.pdf |title=Cleaning with Heat: Old Technology with a Bright New Future |author=Mainord, Kenneth |date=September 1994 |website=Pollution Prevention Regional Information Center |publisher=The Magazine of Critical Cleaning Technology |access-date=4 December 2015 |url-status=live |archive-url=https://web.archive.org/web/20151208133211/http://infohouse.p2ric.org/ref/02/01800.pdf |archive-date=8 December 2015 }}</ref> organic material is converted by pyrolysis and oxidation into [[volatile organic compounds]], [[hydrocarbon]]s and [[Carbonization|carbonized]] gas.<ref name="Thermal Processing 2014">{{cite web |url=http://thermalprocessing.org/2014/03/14/look-thermal-cleaning-technology/ |title=A Look at Thermal Cleaning Technology |date=14 March 2014 |website=ThermalProcessing.org |publisher=Process Examiner |access-date=4 December 2015 |url-status=live |archive-url=https://web.archive.org/web/20151208191756/http://thermalprocessing.org/2014/03/14/look-thermal-cleaning-technology/ |archive-date=8 December 2015 }}</ref> [[Inorganic chemistry|Inorganic]] elements remain.<ref>{{cite web |url=http://infohouse.p2ric.org/ref/30/29295.pdf |title=Cleaning Metal Parts and Tooling |author1=Davis, Gary |author2=Brown, Keith |date=April 1996 |website=Pollution Prevention Regional Information Center |publisher=Process Heating |access-date=4 December 2015 |url-status=live |archive-url=https://web.archive.org/web/20160304031105/http://infohouse.p2ric.org/ref/30/29295.pdf |archive-date=4 March 2016 }}</ref>

Several types of thermal cleaning systems use pyrolysis:
* ''Molten Salt Baths'' belong to the oldest thermal cleaning systems; cleaning with a [[molten salt]] bath is very fast but implies the risk of dangerous splatters, or other potential hazards connected with the use of salt baths, like explosions or highly toxic [[hydrogen cyanide]] gas.<ref name="Mainord1994" />
* ''Fluidized Bed Systems''<ref>{{cite web |url=http://worldwide.espacenet.com/publicationDetails/biblio?FT=D&date=19991007&DB=worldwide.espacenet.com&locale=de_EP&CC=WO&NR=9949999A1&KC=A1&ND=4 |title=Method for removing polymer deposits which have formed on metal or ceramic machine parts, equipment and tools |author1=Schwing, Ewald |author2=Uhrner, Horst |date=7 October 1999 |website=Espacenet |publisher=European Patent Office |access-date=19 April 2016 |archive-date=31 December 2020 |archive-url=https://web.archive.org/web/20201231175822/https://worldwide.espacenet.com/publicationDetails/biblio?FT=D&date=19991007&DB=worldwide.espacenet.com&locale=de_EP&CC=WO&NR=9949999A1&KC=A1&ND=4 |url-status=dead }}</ref> use [[sand]] or [[aluminium oxide]] as heating medium;<ref>{{cite web |url=http://worldwide.espacenet.com/publicationDetails/biblio?CC=DE&NR=2337894A1&KC=A1&FT=D |title=Cleaning objects in hot fluidised bed – with neutralisation of resultant acidic gas esp. by alkaline metals cpds |author1=Staffin, Herbert Kenneth |author2=Koelzer, Robert A. |date=28 November 1974 |website=Espacenet |publisher=European Patent Office |access-date=19 April 2016 |archive-date=31 December 2020 |archive-url=https://web.archive.org/web/20201231175959/https://worldwide.espacenet.com/publicationDetails/biblio?CC=DE&NR=2337894A1&KC=A1&FT=D |url-status=dead }}</ref> these systems also clean very fast but the medium does not melt or boil, nor emit any vapors or odors;<ref name="Mainord1994" /> the cleaning process takes one to two hours.<ref name="Thermal Processing 2014" />
* ''Vacuum Ovens'' use pyrolysis in a [[vacuum]]<ref>{{cite web |url=http://worldwide.espacenet.com/publicationDetails/biblio;jsessionid=1R87vtg4+Shk-VrpqpVUsDVb.espacenet_levelx_prod_3?locale=en_EP&FT=D&CC=US&DB=worldwide.espacenet.com&NR=4220480A&date=19800902&ND=4&KC=A |title=Process for vacuum pyrolysis removal of polymers from various objects |author=Dwan, Thomas S. |date=2 September 1980 |website=Espacenet |publisher=European Patent Office |access-date=26 December 2015 |archive-date=31 December 2020 |archive-url=https://web.archive.org/web/20201231180038/https://worldwide.espacenet.com/publicationDetails/biblio;jsessionid=1R87vtg4+Shk-VrpqpVUsDVb.espacenet_levelx_prod_3?locale=en_EP&FT=D&CC=US&DB=worldwide.espacenet.com&NR=4220480A&date=19800902&ND=4&KC=A |url-status=dead }}</ref> avoiding uncontrolled combustion inside the cleaning chamber;<ref name="Mainord1994" /> the cleaning process takes 8<ref name="Thermal Processing 2014" /> to 30 hours.<ref>{{cite web |url=http://www.thermal-cleaning.com/en/schwing-thermal-cleaning-systems-accessories/vacuum-pyrolysis-systems.html |title=Vacuum pyrolysis systems |website=thermal-cleaning.com |access-date=11 February 2016 |url-status=live |archive-url=https://web.archive.org/web/20160215201957/http://www.thermal-cleaning.com/en/schwing-thermal-cleaning-systems-accessories/vacuum-pyrolysis-systems.html |archive-date=15 February 2016 }}</ref>
* ''Burn-Off Ovens'', also known as ''Heat-Cleaning Ovens'', are gas-fired and used in the painting, [[coating]]s, [[electric motor]]s and [[plastic]]s industries for removing organics from heavy and large metal parts.<ref>{{cite web |url=http://www.mntap.umn.edu/paint/resources/56-PaintStrip.htm |title=Paint Stripping: Reducing Waste and Hazardous Material |date=July 2008 |website=Minnesota Technical Assistance Program |publisher=University of Minnesota |access-date=4 December 2015  |archive-url=https://web.archive.org/web/20151208103626/http://www.mntap.umn.edu/paint/resources/56-PaintStrip.htm |archive-date=8 December 2015 }}</ref>

===Fine chemical synthesis===
Pyrolysis is used in the production of chemical compounds, mainly, but not only, in the research laboratory.

The area of boron-hydride clusters started with the study of the pyrolysis of [[diborane]] ({{chem|B|2|H|6}}) at ca. 200&nbsp;°C.  Products include the clusters  [[pentaborane]] and [[decaborane]]. These pyrolyses involve not only cracking (to give {{chem|H|2}}), but also re[[condensation]].<ref>{{cite book |doi=10.1016/C2009-0-30414-6 |title=Chemistry of the Elements |date=1997 |isbn=978-0-7506-3365-9 }}{{pn|date=March 2025}}</ref>

The synthesis of [[nanoparticle]]s,<ref>{{cite journal |last1=Pingali |first1=Kalyana C. |last2=Rockstraw |first2=David A. |last3=Deng |first3=Shuguang |title=Silver Nanoparticles from Ultrasonic Spray Pyrolysis of Aqueous Silver Nitrate |journal=Aerosol Science and Technology |date=October 2005 |volume=39 |issue=10 |pages=1010–1014 |doi=10.1080/02786820500380255 |bibcode=2005AerST..39.1010P }}</ref> zirconia<ref>{{cite journal |last1=Song |first1=Y. L. |last2=Tsai |first2=S. C. |last3=Chen |first3=C. Y. |last4=Tseng |first4=T. K. |last5=Tsai |first5=C. S. |last6=Chen |first6=J. W. |last7=Yao |first7=Y. D. |title=Ultrasonic Spray Pyrolysis for Synthesis of Spherical Zirconia Particles |journal=Journal of the American Ceramic Society |date=October 2004 |volume=87 |issue=10 |pages=1864–1871 |doi=10.1111/j.1151-2916.2004.tb06332.x }}</ref> and oxides<ref>{{cite thesis |last1=Hamedani |first1=Hoda Amani |title=Investigation of deposition parameters in ultrasonic spray pyrolysis for fabrication of solid oxide fuel cell cathode |date=December 2008 |hdl=1853/26670 |hdl-access=free }}</ref> utilizing an [[ultrasonic nozzle]] in a process called ultrasonic spray pyrolysis (USP).

===Other uses and occurrences===
* Pyrolysis is used to turn organic materials into carbon for the purpose of [[carbon-14 dating]].
* Pyrolysis liquids from slow pyrolysis of bark and hemp have been tested for their antifungal activity against wood decaying fungi, showing potential to substitute the current wood preservatives<ref>{{cite journal |last1=Barbero-López |first1=Aitor |last2=Chibily |first2=Soumaya |last3=Tomppo |first3=Laura |last4=Salami |first4=Ayobami |last5=Ancin-Murguzur |first5=Francisco Javier |last6=Venäläinen |first6=Martti |last7=Lappalainen |first7=Reijo |last8=Haapala |first8=Antti |title=Pyrolysis distillates from tree bark and fibre hemp inhibit the growth of wood-decaying fungi |journal=Industrial Crops and Products |date=March 2019 |volume=129 |pages=604–610 |doi=10.1016/j.indcrop.2018.12.049 }}</ref> while further tests are still required. However, their ecotoxicity is very variable and while some are less toxic than current wood preservatives, other pyrolysis liquids have shown high ecotoxicity, what may cause detrimental effects in the environment.<ref>{{cite journal |last1=Barbero-López |first1=Aitor |last2=Akkanen |first2=Jarkko |last3=Lappalainen |first3=Reijo |last4=Peräniemi |first4=Sirpa |last5=Haapala |first5=Antti |title=Bio-based wood preservatives: Their efficiency, leaching and ecotoxicity compared to a commercial wood preservative |journal=Science of the Total Environment |date=January 2021 |volume=753 |pages=142013 |doi=10.1016/j.scitotenv.2020.142013 |pmid=32890867 |bibcode=2021ScTEn.75342013B }}</ref>
* Pyrolysis of [[tobacco]], paper, and additives, in [[cigarettes]] and other products, generates many volatile products (including [[nicotine]], carbon monoxide, and [[tar]]) that are responsible for the aroma and negative [[health effects of tobacco|health effects]] of [[smoking]].  Similar considerations apply to the smoking of [[marijuana]] and the burning of [[incense]] products and [[mosquito coil]]s.
* Pyrolysis occurs during the [[trash incineration|incineration of trash]], potentially generating volatiles that are toxic or contribute to [[air pollution]] if not completely burned.
* Laboratory or industrial equipment sometimes gets fouled by carbonaceous residues that result from [[coking]], the pyrolysis of organic products that come into contact with hot surfaces.