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

Challenges in establishing waste-to-energy projects in developing countries with a case study from India

Municipal solid waste (MSW) management and its scientific disposal is a major concern for the local municipal authorities of all major Indian cities. Under the "Clean India Mission", the Ministry of Urban Development (MoUD) of India is investing US $9 Billion to clean up 75 largest cities in India. Waste to Energy (WTE) plants will be a key to its implementation. Currently, open air burning and landfilling are the most common practices of wase disposal in India. Landfilling is considered the least favourable option for cities as these sites occupy significant land areas in already crowded urban areas. WTE plants or incinerators are considered the most viable solution for safe disposal of MSW all over the world. In India, however, WTE projects have had mixed results and outright failures. Currently, only eight such plants are operational in the country. This is due to several technical, economic, environmental, social and policy factors involved. This study investigates the feasibility of a proposed state-of-the art WTE plant in Delhi which will set an example for other cities to follow. It reviews the various challenges involved in the implementation of such a project and suggests mitigating solutions to overcome these challenges

Techno-economic feasibility of a hybrid power generation system for developing economies

This work investigates the feasibility of hybrid power generation system using multiple energy sources to fulfil the electrical demand of a residential community. The system performance is evaluated against the capital investment, Cost of Electricity (COE), CO2 emissions and Net Present Cost. Results indicate that the hybrid system reduces the COE by 47% compared to grid price and has a negative CO2 emissions of 24,603 kg/yr due to supplying its surplus energy to the grid. Renewable sources contribute to 80.1% of the overall power produced by the hybrid system. The study finds that the hybrid systems could replace complete dependency on grids

Review of Waste to Energy Projects in Developing Countries

Waste to Energy (WTE) projects have been running successfully in many countries but have produced only mixed results in developing and have often been plagued with controversies. This is due to various technical, financial, environmental, political and social factors involved. Hallam Energy at Sheffield Hallam University was commissioned by the Government of India, to conduct a detailed independent investigation into the techno-economic feasibility of such a WTE project in Delhi. The goals of this study were (i) to make an informed decision on whether the proposed WTE facility for Delhi will be technically and financially viable, and (ii) to gain a reasonable understanding of the costs and resources involved in this investment. This work looks at the various challenges associated in setting up WTE plants in developing countries and address key findings including: 1. The capacity of the plant, 2. The capital cost, 3. The electrical power output, 4. Land area requirement, 5. Site selection for the plant, 6. The choice of processes and pre-processing of the feed, 7. Feasibility of trigeneration or CHP, 8. Choice of technologies and equipment, 9. Financial models, 10. Emissions of pollutants, 11. Lessons learnt from past WTE projects in India

Scaling in the Aging Dynamics of the Site-diluted Ising Model

We study numerically the phase-ordering kinetics of the two-dimensional site-diluted Ising model. The data can be interpreted in a framework motivated by renormalization-group concepts. Apart from the usual fixed point of the non-diluted system, there exist two disorder fixed points, characterized by logarithmic and power-law growth of the ordered domains. This structure gives rise to a rich scaling behavior, with an interesting crossover due to the competition between fixed points, and violation of superuniversality.Comment: 13 pages, 8 figure

Phase synchronization of instrumental music signals

Signal analysis is one of the finest scientific techniques in communication theory. Some quantitative and qualitative measures describe the pattern of a music signal, vary from one to another. Same musical recital, when played by different instrumentalists, generates different types of music patterns. The reason behind various patterns is the psychoacoustic measures - Dynamics, Timber, Tonality and Rhythm, varies in each time. However, the psycho-acoustic study of the music signals does not reveal any idea about the similarity between the signals. For such cases, study of synchronization of long-term nonlinear dynamics may provide effective results. In this context, phase synchronization (PS) is one of the measures to show synchronization between two non-identical signals. In fact, it is very critical to investigate any other kind of synchronization for experimental condition, because those are completely non identical signals. Also, there exists equivalence between the phases and the distances of the diagonal line in Recurrence plot (RP) of the signals, which is quantifiable by the recurrence quantification measure tau-recurrence rate. This paper considers two nonlinear music signals based on same raga played by two eminent sitar instrumentalists as two non-identical sources. The psycho-acoustic study shows how the Dynamics, Timber, Tonality and Rhythm vary for the two music signals. Then, long term analysis in the form of phase space reconstruction is performed, which reveals the chaotic phase spaces for both the signals. From the RP of both the phase spaces, tau-recurrence rate is calculated. Finally by the correlation of normalized tau-recurrence rate of their 3D phase spaces and the PS of the two music signals has been established. The numerical results well support the analysis