Continuous Hydrothermal Synthesis of Nanomaterials: From Laboratory to Pilot Plant

摘要：开发了一种新型的实验室规模的连续水热流合成（CHFS）系统，用于无机纳米材料（颗粒<100 nm）的可控合成，这些材料具有潜在的商业应用，从防晒剂和电池材料到燃料电池组件和光催化剂。CHFS系统具有许多优点;它是一种绿色技术（使用超临界水作为试剂），其利用廉价的前体（金属硝酸盐）并且可以在有效的单一步骤（或比常规更少的步骤）中可控地生产高质量、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）向10倍的试点规模扩大（纳米粉末产量高达每12小时500克，取决于变量）。拟议的研究将首先比较在实验室规模下控制CHFS系统在大范围工艺变量（流速、温度、压力等）下的颗粒特性的能力，建立完整的操作包络线，描述反应堆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），数据将有助于开发对时间操作空间以及过程变量和产品质量之间相互作用的单变量和多变量理解。PAT和化学计量学结合计算流体动力学模型的流体动力学/混合和人口平衡模型的粒度演变通过纳米沉淀将用于研究替代喷嘴设计和其他潜在的瓶颈因素。这将导致一项通用战略，用于扩大和控制纳米材料的制造，使其具有一致、可重复和可预测的质量。中试工厂生产的纳米粉末数量的扩大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，这些应用由于缺乏足够的高质量材料而迄今为止无法进行。重要的是，该项目获得的专业知识和拟议的可行性研究将减少未来可能考虑建造更大工业规模CHFS工厂的行业的风险和商业障碍。

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.