| 1. |
- Javed, Muhammad Tayyeb, et al.
(author)
-
Combustion Kinetics Modelling
- 2010
-
In: Handbook of Combustion. - Weinheim, Germany : John Wiley & Sons. - 9783527324491 ; , s. 153-173
-
Book chapter (peer-reviewed)abstract
- Combustion is a complex phenomenon characterized by the interaction and competition of various physical and chemical processes. The correct description of chemical changes requires the application of reaction mechanisms that consist of several hundreds or thousands of elementary reactions. This creates an opportunity for kinetic modeling to play important role in understanding the combustion phenomenon. This chapter provides an overview of combustion modeling, the main aim being to present a comprehensive knowledge base for combustion kinetic modeling. The coupling of fluid dynamics and chemical kinetics using commercial software such as CHEMKIN and FLUENT is also discussed. Moreover, an exemplary approach for reducing complex chemical reaction mechanisms is illustrated with reference to an H2 + O2 mixture in an adiabatic system. This approach involves the identification of redundant species via rate sensitivity analysis, and of redundant reactions, by principal component analysis of the rate sensitivity matrix. An eigenvalue–eigenvector analysis is used to extract meaningful kinetic information from linear sensitivity coefficients computed for all species of chemical mechanism at several time points. The main advantage of this method lies in its ability to reveal those parts of the mechanism, which consist of strongly interacting reactions, and to indicate their importance within the mechanism. By using the above procedures, reduced reaction mechanisms could be developed at different chosen conditions and employed in CFD codes in place of detailed mechanisms, giving due consideration to flow fields.
|
|
| 2. |
|
|
| 3. |
- Ibrahim, Muhammad Asim, et al.
(author)
-
Building smart cities: security against risk for spontaneous fires at temporary storage sites of waste fuels and recyclables
- 2013
-
In: CPEXPO community protection.
-
Conference paper (pop. science, debate, etc.)abstract
- Now a days there is high emphasis on the reuse and recycling of waste which reflects that waste management industry is flourishing all over the word. The environmental and economic benefits connected with increased recycling and reuse of materials is usually considered as paradigm of sustainability societies. However, in past few years, an increased risk of spontaneous fires at temporary storage sites of organic materials, waste fuels and recyclables have been observed which lead to a shift in this paradigm (Ibrahim et al, 2013, Li et al, 2006, Fu et al, 2006). According to an estimate, such spontaneous fires have cost more than 49 million SEK during year 2000 to 2010 to Swedish waste industry (Ibrahim et al, 2013). In past unavailability of data regarding environmental damages and associated social costs of such fires lead to underestimation of hazards posed by such fires. However now there is a growing concern that waste management and recycling industry can pose serious threats to our cities and fire incidents can involve serious social, health and economic implications.Previous research has showed that conventional invasive techniques (gas detectors, thermocouples) are proven to be insufficient to provide protection against risk for spontaneous fires. There is vast opportunity to do research and to investigate the use of non-invasive techniques (Infra-red Cameras) and advanced invasive techniques (Optical fibre cables) to generate early warning signals and continuous monitoring of temporary storage of waste. In our on-going research project regarding monitoring of real waste heaps using IR Thermal cameras, the preliminary data have provided us the opportunity to quantify the uncertainties associated with use of IR thermal cameras. In future we are intended to investigate different aspects regarding the use of IR cameras, such as; angle of orientation of IR camera in reference to heap, separation distance between IR camera and the surface of waste heaps and quantifying the potential of IR camera to detect hot spots inside the waste heaps. In future it is expected that there will be a growing market for such non-invasive probes that can protect our cities from the noxious emissions release from temporary storage sites of waste fuels and recyclables.
|
|
| 4. |
- Ibrahim, Muhammad Asim, et al.
(author)
-
Characterization of municipal solid waste temporary storage sites : Risks posed to surrounding areas as a consequence of fire incidents
- 2013
-
In: Waste Management. - : Elsevier. - 0956-053X .- 1879-2456. ; 33:11, s. 2296-2306
-
Journal article (peer-reviewed)abstract
- In this study temporary storage sites of municipal solid waste were characterized based on their potential social, health and environmental impacts as a consequence of spontaneous fires, by employing Boolean as well as weighted-linear-combination approaches in connection with various fuzzy set functions of population density around the storage sites. Sweden was used as the case study and data from 105 storage sites were analysed; of these, 38 were identified to be posing high risk for downwind residing population. Furthermore, during the past 10 years, the fire frequency and the average population residing within a radius of 1, 2, and 3 km were found to be comparatively higher for storage sites owned by private ompanies than for those owned by municipalities. The study provided first-cut information of poorly sited temporary storage sites and can help in formalizing the comprehensive risk analysis in the future.
|
|
| 5. |
- Ibrahim, Muhammad Asim, et al.
(author)
-
Combustion Characteristics of Municipal Solid Waste Bales
- 2013
-
In: Fire Technology. - : Springer Science and Business Media LLC. - 0015-2684 .- 1572-8099. ; 51:1, s. 109-127
-
Journal article (peer-reviewed)abstract
- Combustion behaviour of municipal solid waste bales is a rarely studied topic hitherto. However, there is dire need to devote research on the topic because baling as a storage methodology is getting popular among waste management companies and fire episodes in such storage sites can have devastating economic, environmental and social implications. In this study, thickness of low density polyethylene (LDPE) plastic sheets (12 layers, 6 layers and no layer) and type of ignition source (pilot ignition, thermal radiation) were investigated to see their effect on combustion behaviour of bales. In total eleven tests with a single bale in each test were performed. It has been found that the bales not wrapped with LDPE plastic sheets may pose higher hazards for adjacently stored material to catch fire as the value of maximum heat release rate observed for them was higher than those wrapped with LDPE plastic sheets. Furthermore, it has been found that LDPE plastic wrapping do not contribute significantly to the combustion of bales when exposed only to thermal radiation from an adjacent fire. However, it plays a significant role in ignition of bales in case exposed to a pilot flame ignition source. Molten LDPE plastic trapped between the adjacently stored bales was found to be another important factor influencing the combustion of bales.
|
|
| 6. |
- Ibrahim, Muhammad Asim, et al.
(author)
-
Fires at storage sites of organic materials, waste fuels and recyclables
- 2013
-
In: Waste Management & Research. - : Sage Publications. - 0734-242X .- 1096-3669. ; 31:9, s. 937-945
-
Journal article (peer-reviewed)abstract
- During the last decade, the European Union has enforced the diversion of organic wastes and recyclables to waste management companies operating incineration plants, composting plants and recycling units instead of landfills. The temporary storage sites have been established as a buffer against fluctuations in energy demand throughout the year. Materials also need to be stored at temporary storage sites before recovery and recycling. However, regulations governing waste fuel storage and handling have not yet been developed, and, as a result, companies have engaged in risky practices that have resulted in a high number of fire incidents. In this study, a questionnaire survey was distributed to 249 of the 400 members of Avfall Sverige (Swedish Waste Management Association), which represents the waste management of 95% of the Swedish population. Information regarding 122 storage facilities owned by 69 companies was obtained; these facilities were responsible for the storage of 47% of the total treated waste (incineration + digestion + composting) in 2010 in Sweden. To identify factors related to fire frequency, the questionnaire covered the amounts of material handled and burnt per year, financial losses due to fires, storage duration, storage method and types of waste. The results show that 217 fire incidents corresponded to 170 kilotonnes of material burnt and cumulative losses of 49 million SEK (€4.3 million). Fire frequency and amount of material burnt per fire was found to be dependent upon type of management group (waste operator). Moreover, a correlation was found between fire frequency and material recycled during past years. Further investigations of financial aspects and externalities of fire incidents are recommended.
|
|
| 7. |
|
|
| 8. |
- Ibrahim, Muhammad Asim, et al.
(author)
-
Organizing preliminary storage sites of organic material, waste fuels and recyclables and their separating distance from populated areas
- 2014
-
In: Journal of Material Cycles and Waste Management. - : Springer Science and Business Media LLC. - 1438-4957 .- 1611-8227. ; 16:2, s. 270-281
-
Journal article (peer-reviewed)abstract
- European Union directives have urged member countries to enhance the recycling and separation of waste fractions, and this has increased the number of temporary storage sites of recyclables and waste fuels. Spontaneous fires at temporary storage sites have become common and pose social/health/environmental risks. Storage sites should be sited sufficiently far from populated regions, so that the concentration of released pollutants from open fires falls below the critical air quality index before the plume reach the downwind population. In this study, the open-burn/ open-detonation model developed by the US Environmental Protection Agency was employed, and 540 simulations were performed for nine scenarios of open burning of household waste to estimate suitable sizes of storage heaps and adequate distances between storage sites and populated regions. Furthermore, sensitivity analysis was performed for 1,080 additional simulations to determine the effects of variations in the burn rate, storage dimension and volume of the waste heap on the model output. The resulting chart can be directly employed by waste operators/ environmental agencies to organize storage sites to minimize externalities due to open fires. Furthermore, using ArcGIS software, first-cut information of the total Swedish population facing the risk of hazards due to spontaneous fires was provided.
|
|
| 9. |
- Ibrahim, Muhammad Asim, et al.
(author)
-
Perception of fire-risk at temporary storage sites of organic materials, waste fuels and recyclables
- 2014
-
In: International Journal of Environment and Waste Management. - : InderScience Publishers. - 1478-9876 .- 1478-9868. ; :2, s. 165-180
-
Journal article (peer-reviewed)abstract
- The risk of fires at municipal solid waste (MSW) storage sites is of great concern because such fires not only result in material losses worth millions of Euros annually but also have deleterious effects on both human health and the environment. Keeping in view that management decisions addressing risk of fires cannot be divorced from human psychology regarding safety, a questionnaire survey was designed for which 187 respondents gave a response rate of 33%. Survey results showed that three types of biases; optimism, attribution and availability bias, prevail among managers of waste management companies. Furthermore, biased respondents had experienced higher frequency of fire incidents and preferred low cost risk averting technologies. It is concluded that there is a need to acknowledge the existence of biases and to improve the decision making skills of managers with the help of risk awareness programmes and implementation of government steering tools to reduce risk of spontaneous fires.
|
|
| 10. |
- Ibrahim, Muhammad Asim, et al.
(author)
-
Risk of Fires in Temporary Storages of Organic Materials and Waste Fuels: Lessons Learn in Past, Present and Future Perspectives
- 2013
-
In: 8th International Technical Conference on Solid Waste (Jornadas Técnicas Internacionais de Resíduos - JTIR).
-
Conference paper (peer-reviewed)abstract
- The risk of spontaneous fires at temporary storages of organic material waste fuels and recyclables have been observed worldwide. This increase in number of fire incidents is due to increased demands for recovery and recycling of materials and growth in number of temporary storage sites. In past fire incidents have been observed in all types of storages (loose dumps, hard compact and bales). It is concluded that in order to reduce the risk of spontaneous fires there is need to re-consider the economic, political, behavioural and technical factors. Furthermore, in a situation when there is always a risk of spontaneous fires, early detection and early suppression can limit the losses from fires. Three stake holders, government by introducing strong steering tools, waste management companies by developing safety culture and society by source separation can help in reducing the risk of spontaneous fires and help in achieving the dream of sustainable society.
|
|
