Production of Biocrude from Biomass using Supercritical Water

CBET-0828269R。Gupta生物质是全球第四大能源，可以填补石油枯竭造成的燃料供应缺口。利用生物质的关键步骤是将其液化为生物原油。一旦处于液体形式，生物原油可以利用已经被石化工业完善/优化的完善的管道运输、精炼和化学工艺。例如，生物原油可以被氢化以产生汽油或重整以产生氢气。使用亚临界水和超临界水（高于374 PoPC和220巴）进行液化是有利的，因为它可以利用生物质而不干燥。由于其特殊的特性（例如，非极性性质、高扩散性和低粘度），超临界水可以溶解包括生物质的有机化合物。高反应速率允许紧凑型反应器的设计，需要不到一分钟的典型反应时间。纤维素、木质素和半纤维素的快速解聚导致形成相应的单体和低聚物。这一过程也称为水热液化，是本项目的主题。在该过程中，有机材料的氧含量从40重量%降低到10-15重量%，氧以COB 2B和HB 2BO的形式离开。得到的环状分子（例如，来自半纤维素和纤维素的葡萄糖、呋喃和低聚糖）和来自木质素的芳族环状分子（例如酚）可以被氢化以产生类似于汽油的燃料，其是环己烷、甲苯和异辛烷的近似混合物。此外，生物原油本身可以在超临界水中重整，产生高压HB 2B和高压COB 2B（准备封存）。该项目的智力价值在于对所涉及的各个步骤进行基础研究，包括解聚、水解、氧化、脱水和脱羧，以便进行合理的反应器/工艺设计。使用一种新型反应器配置，其利用生物质的半纤维素、纤维素和木质素组分的解聚动力学的差异。反应温度和时间可以通过使用廉价的碱催化剂（例如，KB2BCOB3B、NaB2BCOB3B、KOH）。该项目将利用超临界抗溶剂的概念（注：由于介电常数低，碱金属盐不溶于超临界水）原位生产催化剂纳米颗粒，其新产生的高表面有望具有高催化性。本研究感兴趣的生物质包括半纤维素、纤维素、木质素、柳枝稷、玉米秸秆和南方松。将研究各种工艺参数对整体能源效率的影响。该项目更广泛的影响是利用生物量来满足关键的燃料供应需求。在这个项目中，生物原油将被氢化生产汽油，并被重整生产氢气。如果成功的话，这些结果可以为传统运输使用的液体燃料和未来燃料电池汽车的氢开辟一个新的解决方案。生物质衍生的液体或气体燃料有潜力提供具有成本效益和可持续的能源供应，同时达到温室气体减排目标。对研究生和本科生（包括少数民族学生）的培训将有助于向美国工业转移技术，提高其竞争力。此外，与K-12教师的互动将有助于将可持续燃料的概念带入课堂。该项目的成功完成可能会对美国农业，林业产品和纸浆行业的盈利能力产生影响。

CBET-0828269R. GuptaBiomass, the fourth largest energy source worldwide, can fill in gaps in fuel supply created by the depletion of petroleum. A key step in the utilization of biomass is its liquefaction to biocrude. Once in liquid form, biocrude can utilize well established pipeline transportation, refining and chemical processes that have been perfected/optimized by the petrochemical industry. For example, biocrude can be hydrogenated to produce gasoline or reformed to produce hydrogen. The use of sub- and supercritical water (above 374 PoPC and 220 bar) for liquefaction is advantageous as it can utilize biomass without drying. Due to its special characteristics (e.g., non-polar nature, high diffusivity, and low viscosity), supercritical water can solubilize organic compounds including biomass. The high reaction rates allow for the design of a compact reactor, needing typical reaction times of less than a minute. Rapid depolymerization of cellulose, lignin, and hemicelluloses results in the formation of the respective monomers and oligomers. This process, also termed as hydrothermal liquefaction, is the subject of this project. During this process, the oxygen content of the organic material is reduced from 40 wt% to between 10-15 wt%, with oxygen leaving as COB2B and HB2BO. The resulting cyclic molecules (e.g., glucose, furans, and oligosaccharides) from hemicelluloses and cellulose, and aromatic cyclic molecules (e.g, phenols) from lignin can be hydrogenated to produce fuel similar to gasoline which is an approximate mixture of cyclohexane, toluene, and iso-octane. Also the biocrude can be reformed in supercritical water itself to produce high pressure HB2B and high pressure COB2B (ready for sequestration). Intellectual merit of the project is in the fundamental study of the various steps involved including depolymerization, hydrolysis, oxidation, dehydration, and decarboxylation so that rational reactor/process design can be done. A novel reactor configuration is to be used that makes use of the differences in the de-polymerization kinetics of hemicelluloses, cellulose, and lignin components of the biomass. The reaction temperature and time can be reduced by the use of inexpensive alkali catalysts (e.g., KB2BCOB3B, NaB2BCOB3B, KOH). This project will utilize the concept of supercritical antisolvent (note: alkali salts are insoluble in supercritical water due to low dielectric) to in-situ produce catalyst nanoparticles whose newly generated high surface is expected to be highly catalytic. Biomass of interest for this study includes hemicelluloses, cellulose, lignin, switch grass, corn stover, and southern pine. Impact of various process parameters on the overall energy efficiency will be studied. Broader impact of the project is in the utilization of biomass to address critical fuel supply needs. In this project itself, the biocrude will be hydrogenated to produce gasoline, and reformed to produce hydrogen. If successful, the results can open up a novel solution to the liquid fuels for conventional transportation use and hydrogen for future fuel cell cars. Biomass derived liquid or gaseous fuels have potential to provide a cost-effective and sustainable supply of energy, while meeting the greenhouse gas reduction targets. The training of the graduate and undergraduate students (including minority students) will help transfer technology to the US industry enhancing its competitiveness. In addition, interaction with K-12 teachers will help bring the concepts of sustainable fuel to their classrooms. The successful completion of this project could have an impact on the profitability of farming, forest product, and pulp industries in the United States.