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

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

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

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

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

FUSE Observations of a Full Orbit of Hercules X-1: Signatures of Disk, Star, and Wind

We observed an entire 1.7 day orbit of the X-ray binary Hercules X-1 with the Far Ultraviolet Spectroscopic Explorer (FUSE). Changes in the O VI 1032,1037 line profiles through eclipse ingress and egress indicate a Keplerian accretion disk spinning prograde with the orbit. These observations may show the first double-peaked accretion disk line profile to be seen in the Hercules X-1 system. Doppler tomograms of the emission lines show a bright spot offset from the Roche lobe of the companion star HZ Her, but no obvious signs of the accretion disk. Simulations show that the bright spot is too far offset from the Roche lobe to result from uneven X-ray heating of its surface. The absence of disk signatures in the tomogram can be reproduced in simulations which include absorption from a stellar wind. We attempt to diagnose the state of the emitting gas from the C III 977, C III 1175, and N III 991 emission lines. The latter may be enhanced through Bowen fluorescence.Comment: Accepted for publication in The Astrophysical Journa

Triggered Star Formation in a Massive Galaxy at z=3.8: 4C41.17

Spectropolarimetric observations obtained with the W. M. Keck Telescope of the z=3.8 radio galaxy 4C41.17 show that the UV continuum emission from this galaxy, which is aligned with the radio axis, is unpolarized (P[2sigma] < 2.4%). This implies that scattered AGN light, which is generally the dominant contributor to the rest-frame UV emission in z~1 radio galaxies, is unlikely to be a major component of the UV flux from 4C41.17. The spectrum shows absorption lines that are similar to those detected in the spectra of the recently discovered population of star forming galaxies at z~2-3. A galaxian outflow may contribute partially to the low ionization absorption lines; however, the high velocity wings of the high ionization lines are unlikely to be dominated by a galaxian wind since the implied outflow mass is very large. The detection of stellar absorption lines, the shape of the SiIV profile, the unpolarized continuum, the inability of any AGN-related processes to account for the UV flux, and the similarity of the UV continuum spectra of 4C41.17 and the nearby starburst region NGC 1741B1 suggest that the UV light in 4C41.17 is dominated by young stars. If so, the implied star-formation rate is roughly 140-1100Msun/yr. We discuss the possibility that star formation in 4C41.17 was triggered by the radio source. Our data are consistent with the hypothesis that 4C41.17 is undergoing its major epoch of star formation at z~4, and that by z~1 it will have evolved to have spectral and morphological properties similar to those observed in known z~1 powerful radio galaxies.Comment: 28 pages (Latex text + figures); Accepted for publication in The Astrophysical Journal (Dec 1, 1997 issue

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

Hercules X-1: Empirical Models of UV Emission Lines

The UV emission lines of Hercules X-1, resolved with the HST GHRS and STIS, can be divided into broad (FWHM 750 km/s) and narrow (FWHM 150 km/s) components. The broad lines can be unambiguously identified with emission from an accretion disk which rotates prograde with the orbit. The narrow lines, previously identified with the X-ray illuminated atmosphere of the companion star, are blueshifted at both phi=0.2 and phi=0.8 and the line flux at phi=0.2 is 0.2 of the flux at phi=0.8. Line ratio diagnostics show that the density of the narrow line region is log n=13.4+/-0.2 and the temperature is T=1.0+/-0.2x10^5 K. The symmetry of the eclipse ingress suggests that the line emission on the surface of the disk is left-right symmetric relative to the orbit. Model fits to the O V, Si IV, and He II line profiles agree with this result, but fits to the N V lines suggest that the receding side of the disk is brighter. We note that there are narrow absorption components in the N V lines with blueshifts of 500 km/s.Comment: To be published in the Astrophysical Journa

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