Editing Thermal depolymerization (section)

===Biomass===
Many agricultural and animal wastes can be processed, but these are often already used as [[fertilizer]], animal feed, and, in some cases, as feedstocks for [[paper mill]]s or as low-quality [[boiler]] fuel. Thermal depolymerization can convert these into more economically valuable materials. Numerous [[biomass to liquid]] technologies have been developed. In general, [[biochemical]]s contain oxygen atoms, which are retained during pyrolysis, giving liquid products rich in [[phenol]]s and [[furan]]s.<ref>{{cite journal |last1=Collard |first1=François-Xavier |last2=Blin |first2=Joël |title=A review on pyrolysis of biomass constituents: Mechanisms and composition of the products obtained from the conversion of cellulose, hemicelluloses and lignin |journal=Renewable and Sustainable Energy Reviews |date=October 2014 |volume=38 |pages=594–608 |doi=10.1016/j.rser.2014.06.013|bibcode=2014RSERv..38..594C }}</ref> These can be viewed as partially oxidized and make for low-grade fuels. [[Hydrothermal liquefaction]] technologies dehydrate the biomass during thermal processing to produce a more energy-rich product stream.<ref>{{cite journal |last1=Kumar |first1=Mayank |last2=Olajire Oyedun |first2=Adetoyese |last3=Kumar |first3=Amit |title=A review on the current status of various hydrothermal technologies on biomass feedstock |journal=Renewable and Sustainable Energy Reviews |date=January 2018 |volume=81 |pages=1742–1770 |doi=10.1016/j.rser.2017.05.270|bibcode=2018RSERv..81.1742K }}</ref> Similarly, [[gasification]] produces hydrogen, a very high-energy fuel.