Case Studies

Cynthia Adu

Development of Sustainable Manufacturing Materials From Cellulose Based By-Products

Research Background and challenges:
According to WRAP a million tonnes of paper mill sludge (PMS) is produced annually from recycled fibre in the UK, which is typically used for low and moderate value applications such as land spreading and animal bedding. Paper mill sludge comprises of cellulose fibres and minerals. Cellulose is a highly abundant natural polymer which exhibits mechanical properties; advances in cellulose materials research reveals its desirable properties and opportunity to climb up the value chain for various applications. To understand the potential of upcycling PMS, a review of possible applications and PMS properties is carried out. The aim of the research is to develop a sustainable system, based on the conversion of cellulose by-products derived from paper manufacturing into value added products and businesses.

Key Findings and Impact to Date:

A comprehensive literature and background review of paper mill sludge (PMS) properties and material applications has led to the identification of a potential of 12 material applications. The key finding where as follows;

  • PMS material applications can be grouped under mineral based (cement products) or fibre based (composite boards and polymer reinforcement) materials.
  • The fibre based materials have a diverse range of industrial applications which show a higher value potential than current agricultural land spreading and mineral based materials.
  • The PMS material applications are dependent on the characteristics of the sludge, which vary depending on the paper mill product and process.
  • The characteristics of PMS is distinguished by these main factors; ash, cellulose, lignin, extractives and fibre lengths

This literature review lead to a second report on ‘Characterisation of PMS organic and inorganic contents’, this involved analysis of the paper sludge from the 7 mills associated with the research. The following actions have been undertaken;

  • Research and design experimental methods for analyzing paper sludge characteristics
  • Risk assessment and COSSH for applicable analysis
  • Secure relevant materials, reagents and equipment for analysis Analysis on ash, extractives and fibre length is now being carried out on paper sludge samples, this will be repeated on subsequent batches of PMS. Cellulose and lignin will be determined upon availability of an equipment that is currently being serviced.

Experience on the Programme:

My first 15 months have been very busy as well as my research program which also involved visiting a number of paper mills to understand the processing and to obtain samples I have completed 5 taught modules. I have also attended a cohort week for researchers in sustainability from across the globe and the EPSRC CIM Conference on Industrial Sustainability in Cambridge where I won the best poster prize. With other researchers I entered the Ellen MacArthur hackathon on disruptive innovation and won the Philips Prize.

Tom Everitt, Group Compliance, Manager, Ecoganix

The project is a critical part of the research and development strategy in the current Ecoganix business plan. It has produced interesting data to date and shows great promise. The structure of the project coupled with exposure to the insight of field leading academics has helped to continually demonstrate relevance and value as it has progressed.

Lavinia Bianchi

Ammonia Recovery From Sewage

Research Background and Challenges:
Wastewater Treatment Plants (WWTPs) are essential in our society to treat industrial and municipal wastewater. However, the technology applied has remained the same for over a century. Research shows that 50% of the energy used in WWTPs is employed to pump air that allows removing biologically BOD and ammonium (NH4+). Nutrients like phosphorus and nitrogen are pollutants for the environment, but they are also important resources. In this respect, ammonia (NH3) is the main base for nitrogen fertilisers and its production exceeds 140M tonnes/year. Therefore, it is fundamental that research looks at technologies to recover nutrients and not just remove them. In particular, my research focuses on the development of a sustainable and economically feasible technology for the recovery of ammonia from sewage sludge. Among the current techniques applied (biological treatments, chemical precipitation ion exchange and absorption), in the first year of my EngD, I decided to investigate the chemical precipitation technique. The limitations of this technique are: the cost of the chemical used; a low value of the product recovered (struvite). My main research objective was to optimise this process (i.e. recover more valuable products and recycle the chemical source).

Key Findings and Impact to Date:

During the first year, I investigated the chemical precipitation technique. In particular, I focused on the thermal decomposition of struvite in the solid state, since research showed that it could be thermally decomposed at relatively low temperatures. The expected outcome was to be able to release ammonia and water gas that could then be dissolved into water or condensed. From my research studies, it was highlighted that the mechanism of decomposition of struvite is more complex than expected, showing more than one reaction occurring. It was therefore not possible to remove all the ammonia below 400°C, with 2200 J/g of energy required. These results are not currently economically feasible for the industry and therefore my academic supervisors and I decided to not investigate further. However, with my experiments I was able to derive a kinetic model for the thermal decomposition of struvite, which might be of interest for future publication.

Experience on the Programme:

The CDT cohort is a great opportunity for me because it gives me the chance of achieving a Master’s degree and, at the same time, develop my skills as a researcher. As a chemical engineer, I have always been interested in industrial sustainability and my project is extremely focused on that. Moreover, this program is structured in a way that allows the students to build a good network with students from the other partner universities, but also academics and these connections can be helpful during the course of the project. I feel very lucky to be part of the CDT cohort also because the projects are very industry focused and can open the possibility for both an academic or an industrial career.

Bob Stear, Head of Innovation, Severn Trent Water Plc

We are delighted to be an industrial partner on this Engineering Doctorate CDT programme, collaborating closely with WMG at the University of Warwick, the CDT partners and sponsoring Lavinia’s research into “Ammonia Recovery from Sewage”. A research topic that is an important component of our technology roadmap regarding maximising the recovery of valuable products from wastewater. The benefits to Severn Trent Water are considerable; the EngD programme allows us to advance industrially relevant research in an area we have specifically identified as important to us, it gives the opportunity to build upon our relationships with the universities involved, and provides a great route to bring top quality engineers into the water industry. We find the Engineering Doctorate a very cost-effective model for achieving our research aims, while also providing the opportunity to recruit high calibre technical staff into the business. Lavinia’s work will help us in our aspiration to extract value from wastewater and thereby play a significant role in the emerging circular economy. The EngD programme also allows us to cement our relationships with academia, enabling discussion on a range of topics and opportunities relevant to our business, and ensuring that the selected research projects have the academic rigour necessary for them to be a success.

Christina Froemder

Modifications of Thermoplastics Using Recycled Carbon Fibre

Research Background and challenges:
Carbon fibre (CF) composites is one of the most used lightweight materials in demand. The consequent composite waste (e.g. manufacturing waste, end-of-life products) is constantly increasing. Nevertheless, remanufacturing of recycled CF and closing the loop of carbon composite production is still a huge challenge. Recycled carbon fibres have many potential applications in the composites industry. They can provide a cost effective replacement for expensive virgin carbon fibres as well as modifying the electrical, thermal and mechanical properties of the base polymer. As part of the Sustainable Materials and Manufacturing Group within WMG I focus on common compounding processes and study how recycled carbon fibres can be used. The final aim is to demonstrate the use of developed materials in real life applications in a variety of industries.

Key Findings and Impact to Date:

A fundamental understanding of the effects of fibre length, fibre surface treatment and fibre loading will be developed using hybrid carbon fibre mats supplied by the industrial partner.

In the first instance I have focused on general manufacturing conditions, investigating and developing technologies for incorporating recycled carbon fibres into thermoplastics. Using a cost-effective and basic polymer as matrix results in high porosity composite parts. With modifications of the process parameters and different mould designs it could narrow down to good standard. Focusing on the interphase properties and understanding the attraction between fibre and matrix and the general possibility to wet out the samples will be the next step.

Student Quote:

The Engineering Doctorate within the CDT program is a unique opportunity to combine research at three top class universities and making a direct impact of technology on society with help of my local industry partner ELG Carbon Fibre Ltd. The university cohort gives us access to several devices outside the home university and increase the network possibilities enormously.

Integrated inspiring master modules spread over the first three years giving a base knowledge to the topic and support my professional development.

Industry Quote:

Frazer Barnes, Managing Director, ELG Carbon Fibre Ltd

The Eng D programme has allowed ELG Carbon Fibre to expand its R&D portfolio to address areas of technology that are important in the medium to long term. As an SME, internal R&D resources are often focussed on short term needs, and this ability to plan and carry out work aimed at longer term developments is an important part of the company’s growth strategy. A further benefit that derived from the Eng D programme is access to high quality academic input and excellent R&D facilities across a range of leading universities, which an SME would not normally be able to fund on a commercial basis. The quality of the work is also enhanced through the interactions between students working in related fields—opening up new avenues and approaches for investigations. Overall, ELG Carbon Fibre sees the Eng. D programme as an integral part of its R&D strategy and a key component of its future growth plans.

Adam Azenic

Optimising Wood Log Stove Performance by Using Computational Fluid Dynamics

Research Background and challenges:

A wood stove has been historically the main residential heating appliance and still holds a very important place, mostly in regions of good availability and due to the low price of wood. In recent years the stoves burning efficiency has grown due to environmental protection standards, higher wood price and manufacturers better understanding of combustion mechanisms. However, new technologies have still not been applied in the R&D sector to its fullest extent: very few CFD (Computational Fluid Dynamics) modelling approaches have been tested and implemented.

Therefore, the aim of this EngD project is to review, develop, test and apply a CFD analysis method for designing and optimising a typical stove geometry including the combustion chamber and it’s heat exchanging surfaces.

The challenges to this project are:

  • Limited amout of existing research on CFD application to wood burning stoves design
  • Complexity of combustion analysis in CFD
  • Computational cost and fidelity of simulations

Variety of different models needed to be implemented

Key Findings and Impact to Date:

In the first year, a literature review of the physical and chemical mechanisms related to wood drying, pyrolysis, gasification, char and volatile combustion has been carried out. Moreover, numerical models for combustion and chemistry, as well as different stove designs that are present at the market have been reviewed. The physical problem needed to be simulated has been identified.

During the first year,

Work in progress:

  • A collaboration with a research group from Austria is being arranged.
  • Radiation simulations for hearth floor temperatures are being conducted.

Application of different combustion models on 2D axially symmetric mesh of burner jet cases are being conducted

Experience on the Programme:

An EngD CDT programme offers a great opportunity for collaboration with industrial partners, as well as other academics in partner universities or other ones. During the three years of Master’s studies I will get to know my CDT colleagues, professors and other people with the same research topic. It is unique in this programme that at the same time an EngD researcher can be academically active, as well as engaged directly in industrial problems with their industrial partners. I look forward to conducting my research and collaborating with my project partners in order to deliver the projects exciting main aims.

Mike Stonemann, Head of Engineering, Hunter Stoves

There is real value to our company investing in studentships that add profitability to our business by optimising stove performance. We were so pleased with the initial research from Adam’s project that we have now started a second project to invent a new a paint with enhanced heat resistant properties