Continuous Hydrothermal Synthesis of Nanomaterials: From Laboratory to Pilot Plant

摘要：一种新型的实验室规模的连续热液流合成（CHFS）系统已经开发出来，用于无机纳米材料（颗粒<100nm）的受控合成，具有潜在的商业应用，从防晒霜和电池材料到燃料电池组件和光催化剂。CHFS系统有很多优点；这是一种绿色技术（使用超临界水作为试剂），它利用廉价的前体（金属硝酸盐），可以在一个有效的单一步骤（或比传统方法更少的步骤）中可控地生产出高质量的、技术上重要的功能纳米材料。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）推向x10的中试规模（每12小时生产高达500克的纳米粉末，具体取决于变量）。拟议的研究将首先在实验室规模上比较在大范围的工艺变量（流量、温度、压力等）上控制CHFS系统颗粒特性的能力，建立完整的操作信封，描述反应器变量与每种材料的颗粒特性。特别是，我们将利用过程分析技术（PAT），这些数据将有助于发展对时间操作空间和过程变量与产品质量之间相互作用的单变量和多变量理解。pata和化学计量学结合了流体力学/混合计算流体动力学模型和纳米沉淀颗粒尺寸演变的种群平衡模型，将用于研究替代喷嘴设计和其他潜在的瓶颈因素。这将导致一种通用策略，用于扩大和控制纳米材料的制造，具有一致的、可复制的和可预测的质量。试点工厂的纳米粉末数量的增加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设计或全面的商业评估，这是迄今为止由于缺乏足够的高质量材料而无法进行的。重要的是，从项目中获得的专业知识和拟议的可行性研究将降低风险和商业障碍，这些行业可能会考虑在未来建立一个更大规模的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 process analytical technology (PAT)and the data will help develop univariate and multivariate understanding of the temporal operational spaces and interactions between process variables and product quality. PATand 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.