Continuous Hydrothermal Synthesis of Nanomaterials: From Laboratory to Pilot Plant

摘要：一种新的实验室规模的连续水热流合成(CHFS)系统已被开发出来，用于控制合成无机纳米材料(颗粒&lt；100 nm)，其潜在的商业应用从防晒剂和电池材料到燃料电池部件和光催化剂。CHFS系统有许多优点；它是一种绿色技术(使用超临界水作为试剂)，利用廉价的前体(金属硝酸盐)，可以有效地一步(或比传统步骤少)可控地生产高质量、具有重要技术意义的功能纳米材料。该项目旨在将现有的实验室规模的CHFS系统(在过去几年中在QMUL开发)转向x10试点规模(根据变量，每12小时最多生产500g纳米粉末)。这项拟议的研究首先将在实验室规模上比较CHFS系统在大范围过程变量(流量、温度、压力等)下控制颗粒特性的能力，建立描述每种材料的反应堆变量与颗粒特性的完整操作包络。特别是，我们将利用动态激光光散射颗粒尺寸的在线测量和在线分析方法。这些数据将有助于发展对时间操作空间以及过程变量和产品质量之间的相互作用的单变量和多变量的理解。在线传感和化学计量学将与流体动力学/混合的联合计算流体动力学模型和通过纳米沉淀的颗粒尺寸演变的种群平衡模型相结合，用于研究替代喷嘴设计和其他潜在瓶颈因素。这将导致一种通用战略，用于扩大和控制具有一致、可重复和可预测质量的纳米材料的制造。从试点工厂扩大纳米粉末的数量，将使工业合作伙伴能够在一系列应用中对纳米粉末进行原型制作或全面的商业评估，而到目前为止，由于缺乏足够的高质量材料，他们无法进行这些应用。重要的是，在该项目上获得的技术诀窍和拟议的可行性研究将减少行业的风险和商业障碍，这些行业可能会考虑在未来建造更大规模的CHFS工厂。

Summary: A novel laboratory scale continuous hydrothermal flow synthesis (CHFS) system has been developed for the controlled synthesis of inorganic nano-materials (particles <100nm) with potential commercial applications from sunscreens and battery materials to fuel cell components and photocatalysts. The CHFS system has many advantages; it is a green technology (using supercritical water as the reagent), which utilises inexpensive precursors (metal nitrate salts) and can controllably produce high quality, technologically important functional nano-materials in an efficient single step (or fewer steps than conventionally). This project seeks to move the existing laboratory scale CHFS system (developed over the past few years at QMUL) towards a x10 pilot scale-up (nano-powder production of up to 500g per 12h depending on variables). The proposed research will initially compare the ability to control particle characteristics of the CHFS system at the laboratory scale over a large range of process variables (flow rates, temperatures, pressures, etc), building full operational envelopes that will describe reactor variables versus particle properties for each material. In particular, we will utilise on-line measurement of dynamic laser light scattering particle sizing, and at-line analytical methods. This data will help develop univariate and multivariate understanding of the temporal operational spaces and interactions between process variables and product quality. On-line sensing and chemometrics incorporated with combined computational fluid dynamics modelling of hydrodynamics/mixing and population balance modelling of particle size evolution via nano-precipitation will be used to study alternative nozzles designs and other potential bottleneck factors. This will lead to a generic strategy for scaling up and controlled manufacture of nanomaterials with consistent, reproducible and predictable quality. The scale up quantities of nano-powders from the pilot plant will allow industrial partners to perform prototyping or comprehensive commercial evaluation of nano-powders in a range of applications which they have hitherto not been able to conduct due to lack of sufficient high quality material. Importantly, the know-how acquired on the project and the proposed feasibility studies will reduce the risk and commercial barriers for industry that might consider building a larger industrial scale CHFS plant in the future.