Hydrous pyrolysis 1277718 206097950 2008-04-16T20:44:55Z Dysmondo 6909788 clean up conversion and add links to wiki pages related to units of measure. '''Hydrous [[pyrolysis]]''' refers to the thermal decomposition which takes place when organic compounds are heated to high temperatures in the presence of [[water]]. [[Steam cracking]] is used in the [[petroleum]] industry to produce the lighter [[alkene]]s. Steam cracking uses water in the [[gas]] phase, whereas many hydrous pyrolysis processes use [[superheated water]] in the liquid phase. Hydrous pyrolysis may be a significant process in the creation of [[fossil fuel]]s<ref>Pennisi, Elizabeth, [http://www.findarticles.com/p/articles/mi_m1200/is_n8_v143/ai_13528247 Surreptitiously converting dead matter into oil and coal - Water, Water Everywhere], Science News, February 20, 1993.</ref>. Simple heating without water, anhydrous [[pyrolysis]] has long been considered to take place naturally during the [[catagenesis]] of [[kerogen]]s to fossil fuels. In recent decades it has been found that water under pressure causes more efficient breakdown of kerogens at lower temperatures than without it. The carbon [[isotope]] ratio of [[natural gas]] also suggests that [[hydrogen]] from water has been added during creation of the gas. U.S. patent 2,177,557 <ref>Bergstrom et al, [http://www.google.com/patents?id=-MlwAAAAEBAJ Method of treating wood or lignine or cellulose containing materials for obtaining valuable products], U.S. Patent 2,177,557, issued 24 October 1939</ref>, describes a two-stage process in which a mixture of water, wood chips, and calcium hydroxide is heated in the first stage at temperatures in a range of 220°C.(428°F) to 360°C. (680°F), with the pressure "higher than that of saturated steam at the temperature used." This produces "oils and alcohols" which are collected. The materials are then subjected in a second stage to what is called "dry distillation", which produces "oils and ketones". Temepratures and pressures for this Second stage are not disclosed. Zhang et al. <ref><cite>Zhang et al,. (1999).</cite> [http://www.age.uiuc.edu/bee/RESEARCH/tcc/tccpaper3.htm Thermochemical Conversion of Swine Manure to Produce Fuel and Reduce Waste.] University of Illinois.</ref>, at the University of Illinois, report on a hydrous pyrolysis process in which swine manure is converted to oil by heating the swine manure and water in the presence of carbon monoxide in a closed container. For that process they report that a temperatures of at least 275 °C (527 °F) is required to convert the swine manure to oil, and temperatures above about 335 °C (635 °F) reduces the amount of oil produced. The Zhang et la process produces pressures of about 7 to 18 [[Pascal_%28unit%29|Mpa]] (1000 to 2600 [[Pounds_per_square_inch|psi]] - 69 to 178 [[Atmosphere_(unit)|atm]]), with higher temperatures producing higher pressures. Zhang et al used a retention time of 120 minutes for the reported study, but report at higher temperatures a time of less than 30 minutes results in significant production of oil. A commercialized process using hydrous pyrolysis (see the article [[Thermal depolymerization]]) used by Changing World Technologies, Inc. (CWT) and its subsidiary Renewable Environmental Solutions, LLC (RES) to convert turkey offal reported by Adams et al. <ref>Adams et al. [http://ergosphere.files.wordpress.com/2007/04/cwt_genconflasvegas3_3_04.pdf Converting turkey offal into bio-derived hydrocarbons oil (pdf)]</ref>as a two-stage process, the first stage to convert the turkey offal to hydrocarbons at a temperature of 200 to 300 °C (392 to 572 °F) and a second stage to crack the oil into light hydrocarbons at a temperature of near 500 °C (932 °F). Adams et al report only that the first stage heating is "under pressure"; Lemley <ref>Lemley, Brad (May 2003). [http://discovermagazine.com/2003/may/featoil/ Anything Into Oil.] Discover. </ref>, in a non-technical article on the CWT process, reports that for the first stage (for conversion) a temperature of about 260 ° (500 °F) and a pressure of about 600 psi, with a time for the conversion of "usually about 15 minutes". For the second stage (cracking), Lemley reports a temperature of about 480 °C (896 °F). ==References== {{reflist}} ==External links== * [http://pubs.usgs.gov/dds/dds-067/CHH.pdf A Possible Deep-Basin High-Rank Gas Machine Via Water Organic-Matter Redox Reactions], Leigh C. Price * [http://www.findarticles.com/p/articles/mi_m1200/is_n8_v143/ai_13528247 Surreptitiously converting dead matter into oil and coal - Water, Water Everywhere], Science News, [[February 20]], [[1993]], Elizabeth Pennisi * [http://www.imog.agh.edu.pl/website/program/session/oral/pdf/ovii-3.pdf Hydrogen isotope systematics of thermally generated natural gases], Chris Clayton [[Category:Fossil fuels]] {{organic-chem-stub}}