Processing of high solids content pastes with evolving rheology

Lead Research Organisation: University of Birmingham
Department Name: Chemical Engineering

Abstract

Within the Unilever Beauty and Personal Care (BPC) portfolio, products with a wide range of rheological properties can be found which can be defined by their specific microstructure which includes isotropic solutions, lamellar structured liquids and high solids content pastes. Much research is actively being conducted to gain better understanding in the area of processing of isotropic fluids, yet comparatively limited research is dedicated to the field of high solids content pastes. The proposed research project aims to gain better understanding of the processing challenges for this system.
The manufacture of BPC products is achieved through the sequential addition of raw materials in a defined order, specified rates of addition and controlled temperature profiles. Thus, there are two attributes which vary throughout the manufacturing process of BPC products: (1) increasing fluid level within the batch vessel and (2) variations in rheological properties for each of the intermediate stages, affected by the composition, temperature and processing conditions. These two attributes will impact the achievable mixing inten sity and efficiency, as well as flow characteristics within the vessel and any associated pipework. This, in turn, affects product quality, energy requirements and overall process optimisation. Furthermore, many processes for the manufacture of BPC products involve utilisation of recirculation loops to achieve both top-to-bottom homogeneity within the main vessel and/or efficient incorporation of raw materials within the product (powder additions under vacuum).
The proposed research project aims to explore these three effects (increasing fluid level, variations in rheological properties and microstructure evolution ) for high solids content pastes, achieved through use of dynamic torque measurements, the development of power draw expressions as a function of fluid level in-vessel and flow characterisation techniques, such as positron emission particle tracking (PEPT) and particle image velocimetry (PIV). In addition, the project will explore the computational fluid dynamics (CFD) space to identify an approach that would allow tracking the evolution of the vessel level and product rheology throughout the process, using experimental results for validation .

Planned Impact

The beneficiaries of the research and training of the CDT will be UK industry, the graduates of the programme, the wider academic community, and consumers :

(i) UK industry: the formulation sector is wide and diverse, and our industry partners are world-leading in a number of areas; foods (PepsiCo, Mondelez, Unilever), HPC (P+G, Unilever), fine chemicals (Johnson Matthey, Innospec), pharma (AstraZeneca, Pfizer, Imerys) and aerospace (Rolls-Royce). All projects are cocreated with industry, and cofunded - the majority will be EngD students based in company sites. Industry will benefit in a number of ways: (i) from a supply of trained graduates in this critical area, with > 90% of graduates of the programme to date getting jobs in formulation companies, and (ii) through participation in industry-academia research projects in which students work within the company on projects of practical value, (iii) through the synergy possible between companies in different non-competitive sectors (we have current projects between Mondelez and P+G, and Johnson Matthey and Unilever resulting from CDT linkages). We will also work with Catapult Centres, including the National Formulation Centre at CPI and the MTC at Coventry, to enhance the industry relevance of the CDT and train students in modern manufacturing methods.

(ii) Graduates of the programme: students are trained in a critical area where graduates are in short supply, obtain training and experience of the issues involved in industrial and collaborative research, present their work at external and internal meetings and get good jobs (>90% within formulation companies). Many of our graduates are now reaching senior positions in industry, and one, Dr Stewart Welch of Rolls Royce, is now the representative of Rolls-Royce on our Industrial Management Committee. In the next 5 years we will build at least 50 new projects with companies, creating EngD and PhD graduates, a new generation of leaders for the formulation industries.

(iii) Wider academic community in the UK and elsewhere. We will ensure that students on the programme write papers (as many as possible with industrial co-authors) on formulation projects. This is a vital part of the CDT, as it both ensures and demonstrates the academic quality of the programme. We have published extensively in areas such as; soft solid mixing processes (Unilever, Johnson Matthey; see Hall et al., Chem.Eng. Res. Des. 91, 2156-2168, 2013); food materials for enhanced mouthfeel, low-salt and low-sugar delivery, (Pepsico, Nestle, Mondelez; such as Moakes et al RSC Advances 5, 60786-60795, 2015); design of innovative cleaning strategies (Unilever, GSK, Heineken, P+G; Food Bioprod. Proc., 93, 269-282, 2015); characterisation of domestic cleaning processes (washing machines and dishwashers) to minimise water usage (P+G; Chem.Eng Sci., 75, 14, 2012); in-vitro models for formulated product breakdown and nutrient and drug delivery in the mouth, stomach and GI tract; EngD work followed up by BBSRC and industry funding (Eur J Nutr. 55, 2377-2388, 2016); dynamics of spray driers (P+G, AIChE J 61 1804-1821 2015; Chem. Eng. Sci. 162, 284-299, 2017), and ways to reduce waste in soyamilk production (Unilever; Innovative Food Science & Emerging Technologies, 41, 47-55, 2017).

(iv) consumers: many of the companies we work with are involved in Fast Moving Consumer Goods, where research has direct consumer benefit, for example in the creation of low fat foods that have high-fat mouthfeel. In addition, the overall aim of the programme is to develop sustainable formulated products and processes; such materials will be better for the environment and consumers.

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/S023070/1 01/10/2019 31/03/2028
2789106 Studentship EP/S023070/1 03/10/2022 02/10/2026 Shreyasi Deshpande