Waste Heat Recovery in Food and Drinks Industry (Abstract only)

Most baking processes in the food manufacturing sector involve use of gas-fired ovens. Only about one-third of the total energy used in these ovens adds value to the final product. The remaining two-thirds is discharged with the exhaust gases at 150-250o C and thus represents an opportunity for heat recovery. However, the low temperature range, fouling and presence of corrosive materials in the exhaust streams make heat recovery technically challenging and uneconomical. The existing low grade heat recovery technolgies mostly use gas to liquid heat transfer to produce hot water for use in other areas of the manufacturing plant. The performance of these systems is governed by hot water demand in the factory and is therefore not recommended if there are frequent fluctuations in demand or if a more efficient technology, such as combined heat and power, is already in place. This study involves design, manufacturing and testing of a novel low-temperature gas to gas heat recovery system using an array of heat pipe heat exchangers, for industrial-scale baking ovens at a large confectionary manufacturing plant. Unlike gas to liquid heat transfer, a gas to gas heat transfer system provides direct savings in oven fuel consumption, independent of the hot water and other energy demands elsewhere in the plant. The heat recovery potential of the system is estimated using a thermodynamic model developed based on energy and mass balance for the ovens. The design enables recovery of up to 50% of the energy available through the exhaust stack, increasing the energy efficiency of the overall process to 60% and reducing food manufacturing costs by one third

A Novel Deep Learning Model for the Detection and Identification of Rolling Element-Bearing Faults

Real-time acquisition of large amounts of machine operating data is now increasingly common due to recent advances in Industry 4.0 technologies. A key benefit to factory operators of this large scale data acquisition is in the ability to perform real-time condition monitoring and early-stage fault detection and diagnosis on industrial machinery—with the potential to reduce machine down-time and thus operating costs. The main contribution of this work is the development of an intelligent fault diagnosis method capable of operating on these real-time data streams to provide early detection of developing problems under variable operating conditions. We propose a novel dual-path recurrent neural network with a wide first kernel and deep convolutional neural network pathway (RNN-WDCNN) capable of operating on raw temporal signals such as vibration data to diagnose rolling element bearing faults in data acquired from electromechanical drive systems. RNN-WDCNN combines elements of recurrent neural networks (RNNs) and convolutional neural networks (CNNs) to capture distant dependencies in time series data and suppress high-frequency noise in the input signals. Experimental results on the benchmark Case Western Reserve University (CWRU) bearing fault dataset show RNN-WDCNN outperforms current state-of-the-art methods in both domain adaptation and noise rejection tasks

Easy flowing emulsion (o/w) based spray-dried powder produced using dietary fiber as a wall material

The production of emulsion (o/w) based microstructured food powder through spray drying is a common practice in the food industry due to better shelf-life and easy transportation of the structured material. In general, the emulsion based powder flow behavior is poor due to lipid phase diffusion into the surface. The microstructure transform during spray-drying and the reconstitution of the emulsion powder are also a challenge by preserving the desired physiochemical properties such as emulsion size, stability, the control release kinetics of actives etc. The main objective of this study is to encapsulate the lipid phase using a wall material composed of protein (whey protein) and apple fiber. The stable submicron emulsions (o/w) were prepared using a rotor-stator at room temperature. Different fiber concentrations and different spray drying conditions were tested by varying the air to liquid mass ratio (ALR). The easy flowing of the emulsion powder was achieved when a relatively small amount (max. 5%) of fiber was used; however, the flowing performance declines with higher fiber content. The excellent reconstitution of the emulsion was also found by dissolving the particles at room temperature

Electrosprayed particles derived from nano-emulsions as carriers of fish oil

Fish oil encapsulated submicron particles were produced by electrospraying emulsions. Emulsions were homogenized by various pressures (1000 and 2000 bar) and passes (1,2, 4, and 8). The physical properties of the emulsions were evaluated, namely droplet size, stability, microstructure, and rheology. Various physicochemical characterizations of the prepared particles were carried out, including the morphology and size of the electrosprayed particles, and the encapsulation efficiency of the fish oil. In optimised conditions, nano-emulsions were produced (d50 < 100 nm). It was found that the homogenization parameters of the emulsions affect the structure of the particles. Low emulsion viscosity combined with low oil droplet size and high stability yielded particles with the smallest diameters. The proposed emulsion electrospraying technology could be promising for the production of powdered ingredients enriched with omega-3

Performances Comparison between Real-Time Auto-Tuning PID and Conventional PID Controller for a Dairy Industrial Evaporation Process Control

In this study, an industrial milk evaporation process is introduced and a mathematical model of a multi-effect falling film evaporator is developed using MATLAB/Simulink to evaluate the performance of the controller. A real-time closed-loop auto-tuning PID controller is presented as a candidate control strategy for the evaporation process. The simulation results controlled by autotuning and conventional PID are compared and discussed and the performance improvement by the auto-tuning PID controller is illustrated

Comparative study on the rice bran stabilization processes: A review

Rice bran is an undervalued/underutilized by-product of rice milling, rich in protein, lipids, dietary fibers, vitamins, and minerals. It is an inexpensive source of high-quality protein, fiber and lipids to be incorporated into value-added food products. The issue with rice bran is its susceptibility to rancidity and therefore measures must be taken to stabilize the bran in order for it to be fully utilized. Due to this susceptibility to rancidity, historically the bran has either been disposed and wasted or used as low-grade animal feed. As the nutritional value of the bran has been recognized, along with its potential to add value to food products, research has been increasing in volume in order to determine the most effective methods for stabilizing the bran and extracting the valuable nutrients from it. It’s been reported that a free fatty acid content of over 5% is considered to render the bran unfit for human consumption (Tao, Rao & Liuzzo, 1993). Therefore, controlling this level of rancidity is imperative to being able to store and use rice bran over extended periods of time. In order to achieve control, stabilization procedures can be carried out on the rice bran to slow down the lipase activity within the bran and preserve the nutritional qualities that rice bran possesses. Stabilization of rice bran is particularly important for use over winter months in developing countries, where there may be no crops to harvest and therefore a supply of non- rancid rice bran could be extremely beneficial. This length of storage for stabilized rice bran could be up to a period of 6 months, where it can become important for value-added product development (Bagchi, Adak & Chattopadhyay, 2014). The present review will provide an overview of the traditional and innovation rice bran stabilization techniques, those have been a common interest in the research community, and the suitability of the process in terms of the energy consumption

A performance evaluation of commercial fibrinogen reference preparations and assays for Clauss and PT-derived fibrinogen

The wide availability of fibrinogen estimations based on the prothrombin time (PT-Fg) has caused concern about the variability and clinical utility of fibrinogen assays. In a multi-centre study, we investigated fibrinogen assays using various reagents and analysers, Clauss assays generally gave good agreement, although one reagent gave 15-30% higher values in DIC and thrombolysis. Two commercial reference preparations had much lower potencies than the manufacturers declared, and plasma turbidity influenced parallelism in some Clauss assays, PT-Fg assays gave higher values than Clauss and showed calibrant dependent effects, the degree of disparity correlating with calibrant and test sample turbidity. Analyser and thromboplastin dependent differences were noted. The relationship between Clauss and PT-Fg assays was sigmoid, and the plateau of maximal PT-Fg differed by about 2 g/l between reagents. ELISA and immunonephelometric assays correlated well, but with a high degree of scatter. Antigen levels were higher than Clauss, but slightly lower than PT-Fg assays, which appeared to be influenced by degraded fibrinogen. Clauss assays are generally reproducible between centres, analysers and reagents, but PT-Fg assays are not reliable in clinical settings

Achieving operational excellence for industrial baking ovens

A series of experiments were performed on industrial baking ovens across five confectionery manufacturing sites around the world. The impact of different operating parameters such as air and fuel flowrates, oven temperature, exhaust flowrates and ambient temperature etc., on the product quality and overall oven performance were investigated. The energy flows through the baking oven were modelled using experimentally determined inputs to estimate the reduction in heat losses. A step change in operational efficiency was achieved through the study delivering 8.5% improvement in the oven performance. On average, 92 tonnes/annum of CO2 were saved from each oven. An additional 7% efficiency improvement was observed by integrating the baking oven with a heat recovery technology saving circa £16k in fuel cost annually from a single oven. The observations and learnings from the work are not limited to baking ovens only, but can also be applied to other food manufacturing processes such as frying, broiling, roasting or grilling

Waste heat recovery from industrial baking ovens

Under this work, a system level energy model of an industrial-scale baking oven with an integrated waste heat recovery unit is developed using experimentally determined inputs to estimate the potential benefits of a gas-to-gas heat recovery system. This work has demonstrated that at least 4% savings in the oven fuel consumption can be achieved, reducing the annual running costs by £4,207. An environmental assessment indicates reduction of circa 43 tonnes in CO2 emissions per annum. The study also provides a systematic methodology to test low temperature gas-to-gas heat recovery technology for food manufacturing process