VALORIZATION OF SOLID DIGESTATE THROUGH AUTOTHERMAL HYDROTHERMAL LIQUEFACTION

通过自热水热液化对固体沼渣进行增值

• 批准号: 2140146
• 负责人: Robert Brown
• 金额: $ 32.99万
• 依托单位: Iowa State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-01-01 至 2024-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2140146&HistoricalAwards=false
• 关键词: VALORIZATION; SOLID; DIGESTATE; THROUGH; AUTOTHERMAL

This project explores new ways to address the growing problem of wet wastes ranging from animal manure produced on farms, to wastewater from processing fruits and vegetables in the food industry. Wet wastes usually contain more water than solid material wastes, preventing the normal transport and storage at landfills or treatment by burning. Instead, biological processes are often employed to treat wet wastes, but these processes are slow and often leave a significant solid residue requiring special disposal. This project explores the hydrothermal liquefaction (HTL) process, a high-temperate, high-pressure process that dissolves oxygen into the wet wastes, to convert this waste into liquid fuel without requiring external energy sources to drive the process. By turning waste into liquid fuel, the process both eliminates the waste and generates a valuable product. If successful, this project will provide new ways to scale up HTL processes to make them available for more common use, thereby strengthening the Nation’s energy security while reducing the amount of waste from agriculture and other food industries. This project will also train postdoctoral researchers graduate students to effectively mentor their own students in future engineering efforts through the use of a tiered mentoring approach guided by the lead investigator.This goal of this project is to intensify hydrothermal liquefaction (HTL) through directly coupled autothermal operation. This operation will overcome the heat transfer bottleneck of providing energy to the process and allow for scale-up to commercial use. Previous research at Iowa State University demonstrated autothermal operation of a fast pyrolyzer by admitting a small amount of air to the reactor. This increase in oxygen achieved a three-fold increase in throughput compared to conventional (non-oxidative) pyrolysis with minimal loss in bio-oil production. This study proposes a similar autothermal operation of an HTL reactor, providing the enthalpy for the process through partial oxidation of some of the low value aqueous phase products of liquefaction. It is hypothesized that oxygen will preferentially dissolve in the aqueous fraction of HTL products where it will readily react with dissolved organics. In contrast, the more valuable biocrude, an emulsion suspended in the aqueous fraction with far less exposure to the dissolved oxygen, will not substantially oxidize. The approach to this project is to develop a calorimetric HTL reactor that will allow energy flows as well as product composition to be determined during HTL of solid digestate from anaerobic digestion of animal manure. Experiments under both inert and oxidative environments will determine the extent that the enthalpy for liquefaction can be provided by partial oxidation of the less valuable products of liquefaction. The oxidation of organic compounds in high temperature, high pressure aqueous environments has been little studied outside wet oxidation of dissolved solids at atmospheric conditions. If successful, this research will help remediate the approximately 565 teragrams of wet waste generated annually in the United States. Additionally, the scientific and engineering principles implemented in this work will serve as foundational research required for the process intensification of HTL for a range of wet wastes including agricultural residue, food wastes, municipality solid wastes, sewage sludge, and animal manure. A formal postdoctoral researcher and graduate student mentoring structure, combined with effective outreach to kindergarten through twelfth grade students, will help inspire new and train future researchers in these engineering practices.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

该项目探索了解决日益严重的湿废物问题的新方法，从农场产生的动物粪便到食品工业中水果和蔬菜加工产生的废水，湿废物通常比固体材料废物含有更多的水，阻碍了正常的运输和储存。相反，通常采用生物工艺来处理湿废物，但这些工艺速度缓慢，并且常常会留下大量需要特殊处理的固体残留物。高温高压过程，将氧气溶解到湿废物中，将废物转化为液体燃料，无需外部能源来驱动该过程。通过将废物转化为液体燃料，该过程既消除了废物，又产生了有价值的资源。如果成功，该项目将提供新的方法来扩大 HTL 工艺，使其更普遍使用，从而加强国家的能源安全，同时减少农业和其他食品工业的废物量。该项目还将培训博士后。研究人员研究生有效地指导他们通过使用由首席研究员指导的分层指导方法，指导自己的学生参与未来的工程工作。该项目的目标是通过直接耦合自热操作强化水热液化（HTL），该操作将克服提供能量的传热瓶颈。爱荷华州立大学之前的研究表明，通过向反应器中引入少量空气，可以实现快速热解器的自热操作，从而使氧气增加三倍。与传统（非氧化）热解相比，产量增加，生物油生产损失最小。本研究提出了类似的 HTL 反应器自热操作，通过部分低价值水相的部分氧化为该过程提供热函。据了解，氧气会优先溶解在 HTL 对比产品的水相中，它很容易与更有价值的生物原油中的溶解有机物发生反应。该项目的方法是开发一种量热 HTL 反应器，在固体消化物的 HTL 过程中确定能量流和产品成分。在惰性和氧化环境下进行的实验将确定通过部分氧化较低价值的产物可以提供液化热的程度。除了大气条件下溶解固体的湿式氧化之外，对高温高压水环境中有机化合物的氧化的研究很少，如果成功，这项研究将有助于修复美国每年产生的约 565 太克湿废物。此外，这项工作中实施的科学和工程原理将作为对一系列湿废物（包括农业残留物、食品废物、市政固体）进行 HTL 工艺强化所需的基础研究。正式的博士后研究员和研究生指导结构，再加上对幼儿园到十二年级学生的有效推广，将有助于激励新的研究人员并培训未来的这些工程实践研究人员。该奖项反映了 NSF 的法定使命和通过使用基金会的智力价值和更广泛的影响审查标准进行评估，该项目被认为值得支持。