Electro-osmosis Dewatering as an Energy Efficient Technology for - PowerPoint PPT Presentation

2 nd International Conference on Sustainable Energy and Resource Use in Food Chains Electro-osmosis Dewatering as an Energy Efficient Technology for Drying Food Materials Abhay Menon, Tonderai Reuben Mashyamombe, and Valentina Stojceska* Institute for Energy Futures, Brunel University London Paphos, 18 th October 2018 RCUK Centre for Sustainable Energy Use in Food Chains

2 nd International Conference on Sustainable Energy and Resource Use in Food Chains • Economic and environmental impacts of high energy use in UK food industries. • Policies implemented by UK Government to solve this problem • Introduction to electro osmosis (EO) dewatering technology • Design and setup of electro-osmotic dewatering system • Experimental parameters and food products used for dewatering • Performance evaluation and comparison of moisture losses, energy consumption, tariffs and environmental impact of EO with thermal drying. RCUK Centre for Sustainable Energy Use in Food Chains Institute of Energy Futures, Brunel University London

2 nd International Conference on Sustainable Energy and Resource Use in Food Chains Energy consumption in UK food industries • It is estimated that food chains are responsible for 18 % of total UK energy use with ca. 176 MtCO 2 e emissions [1]. • Approximately 65 % of total energy use in food industries are consumed in food manufacture and processing. • A huge proportion of this energy (36%) is consumed by heating processes (dryers, boilers, pre-treatment, coating etc.). RCUK Centre for Sustainable Energy Use in Food Chains Institute of Energy Futures, Brunel University London

2 nd International Conference on Sustainable Energy and Resource Use in Food Chains Government regulations imposed on UK food industries • UK was the first country to imply Carbon budgets (Climate change act, 2008) to curb the greenhouse gases that an organization can emit. The 3 rd Carbon budget (2018-2020) has proposed to reduce the GHG emissions by 37% from year 1990 ’s level. • UK is committed to reducing 10-15 % of energy consumption and water usage by 2020, in agreement with Kyoto protocol (EU, 2012). UK Carbon Budget forecasts (Climate Change Act, 2008) 5th Carbon budget (2028 to 2032) 57 % below 1990 levels 4th Carbon budget (2023 to 2027) 51 % below 1990 levels 3rd Carbon budget (2018 to 2022) 37 % below 1990 levels 2nd Carbon budget (2013 to 2017) 31 % below 1990 levels 1st Carbon budget (2008 to 2012) 25 % below 1990 levels -300 200 700 1200 1700 2200 2700 3200 Budgeted level of carbon dioxide emission (MtCO 2 e) RCUK Centre for Sustainable Energy Use in Food Chains Institute of Energy Futures, Brunel University London

2 nd International Conference on Sustainable Energy and Resource Use in Food Chains • Drying uses 12-20 % of the total energy consumed in food manufacturing industries [2]. • Over 85 % of all industrial dryers are thermal based with energy efficiency values as low as 30 % [3]. • With such high GHG emissions and high costs incurred, the development of innovative drying technology with higher energy efficiency for food industries have Image source: Amisy, China become imperative. • • • Hybrid dryers Vacuum dryers Heat pump dryers • • • Spray dryers Adsorption dryers Microwave based dryers • • • Refractance window drying Freeze dryers Infrared dryers RCUK Centre for Sustainable Energy Use in Food Chains Institute of Energy Futures, Brunel University London

2 nd International Conference on Sustainable Energy and Resource Use in Food Chains Electro-osmosis dewatering system RCUK Centre for Sustainable Energy Use in Food Chains Institute of Energy Futures, Brunel University London

2 nd International Conference on Sustainable Energy and Resource Use in Food Chains pH meter Temperature probe (+) Food material (-) Water outlet Water outlet Mechanical hoist Beaker Dewatered moisture RCUK Centre for Sustainable Energy Use in Food Chains Institute of Energy Futures, Brunel University London

2 nd International Conference on Sustainable Energy and Resource Use in Food Chains Food materials analysed and parameters Egg whites Yogurt Orang juice (pulp) Exposure time (min) Voltage (V) 15 15 30 30 RCUK Centre for Sustainable Energy Use in Food Chains Institute of Energy Futures, Brunel University London

2 nd International Conference on Sustainable Energy and Resource Use in Food Chains Moisture loss after dewatering Yogurt 100 83.74a 80.41ab Moisture content (%) 75.65c 76.45b 71.76cd 80 68.80c 59.86d 60 40 20 0 Initial moisture content EO 30 V 30 min EO 15V 30 min EO 30 V 15 min EO 15 V 15 min T 30 min T 15 min Egg whites Moisture content (%) 100 76.58a 76.10a 75.69a 76.24a 75.61a 76.24a 74.13ab 80 60 40 20 0 Initial moisture content EO 30 V 30 min EO 15V 30 min EO 30 V 15 min EO 15 V 15 min T 30 min T 15 min Orange juice Moisture content (%) 90.71a 89.85a 90.21a 90.25a 90.56a 90.07a 90.46a 100 80 60 40 20 0 Initial moisture content EO 30 V 30 min EO 15V 30 min EO 30 V 15 min EO 15 V 15 min T 30 min T 15 min RCUK Centre for Sustainable Energy Use in Food Chains Institute of Energy Futures, Brunel University London

2 nd International Conference on Sustainable Energy and Resource Use in Food Chains EO/ Thermal dewatering Energy and Cost evaluation The yearly evaluation of the performance of EO were calculated based on the following assumption; • Both EO and Thermal dryers were used on an average of 8 h a day, for 253 days excluding weekends and bank holidays • The unit rate for power consumption commercially is estimated as £0.11676 (npower, United Kingdom 2017) • Therefore, the assumed working hours (X) per year is; X= 8 * 253= 2024 h The electrical energy (E) in kWh is calculated based on the following equation where Voltage (V) is constant and Current (I) is measured [4]; 𝑊∗𝐽 𝐹 = ׬ 1000 𝑒𝑢 RCUK Centre for Sustainable Energy Use in Food Chains Institute of Energy Futures, Brunel University London

2 nd International Conference on Sustainable Energy and Resource Use in Food Chains Electrical energy consumption per year 1200 Thermal 1012 1000 E p.y = E * X Electrical energy consumed (kWh) 800 600 400 Electro-osmosis 198 200 91 52 40 26 12 0 EO 30V EO 15V T Yogurt Egg whites Orange juice RCUK Centre for Sustainable Energy Use in Food Chains Institute of Energy Futures, Brunel University London

2 nd International Conference on Sustainable Energy and Resource Use in Food Chains Cost p.y =E * X * 0.11676 Operating Cost An estimated parameter per year in GBP. reduction of 80% Yog 30 V £ 23.16 operational costs per Yog 15 V £ 6.14 annum could E W 30 V £ 3.07 be achieved by E implementing O E W 15 V £ 1.40 EO in OJ 30 V £ 10.63 industries! Cost evaluation OJ 15 V £ 4.72 Thermal £ 118.16 RCUK Centre for Sustainable Energy Use in Food Chains Institute of Energy Futures, Brunel University London

2 nd International Conference on Sustainable Energy and Resource Use in Food Chains Carbon Footprint evaluation The emission conversion factor for electricity Operating Carbon dioxide Percentage is 0.28307 kgCO 2 e per kWh unit of parameter emission (kgCO 2 e) differences with thermal drying (%) consumption (Department of Environment Yog 30 V 56.04 81 Food and Rural Affairs, UK, 2018). CFE= 0.28307 * E p.y Yog 15 V 14.71 95 E W 30 V 7.35 97 E W 15 V 3.39 99 OJ 30 V 26.32 91 OJ 15 V 11.32 93 Thermal 286.46 Image source : Carbon trust RCUK Centre for Sustainable Energy Use in Food Chains Institute of Energy Futures, Brunel University London

2 nd International Conference on Sustainable Energy and Resource Use in Food Chains Changes in pH during drying 14 Yogurt 15 V 12 Yogurt 30 V 10 8 pH 6 4 2 0 14 Egg whites 15 V 12 Egg whites 30 V 10 8 pH 6 4 2 0 14 Orange juice 15 V 12 Orange juice 30 V 10 8 pH 6 4 2 0 0 5 10 15 20 25 30 Time (min) RCUK Centre for Sustainable Energy Use in Food Chains Institute of Energy Futures, Brunel University London

2 nd International Conference on Sustainable Energy and Resource Use in Food Chains Conclusions • A laboratory scale model of electro-osmosis dewatering system was successfully implemented . • Results showed enhanced energy efficiency, low costs and reduced carbon footprints . • Among the three food materials tested, the moisture content after dewatering showed a significant reduction and pH values varied depending on the extent of electro-osmotic flow of water and electrical interferences with food matrix . • Prolonged exposure with high potential (30 min 30 V) showed an enhanced dewatering rate compared to lower settings. • Future research on EO shall be focussed on analysing the quality aspects (phenolic compounds, AO, sensory evaluation etc.) of food materials after dewatering. RCUK Centre for Sustainable Energy Use in Food Chains Institute of Energy Futures, Brunel University London

2 nd International Conference on Sustainable Energy and Resource Use in Food Chains RCUK Centre for Sustainable Energy Use in Food Chains Institute of Energy Futures, Brunel University London