Typescript. / Digitized by Kansas Correctional Industries

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Digitized by Kansas Correctional Industries

Typescript. / Digitized by Kansas Correctional Industries

Thesis (MScAgric)--University of Stellenbosch, 1985. / Bibliographical references. Also available via the Internet.

Meat and bone meal (MBM) is a byproduct of the rendering industries. It is found to be responsible for the transmission of bovine spongiform encephalopathy (BSE) in animals and is no longer used as a feed to animals. There are various methods for disposal of MBM such as land filling, incineration, combustion, pyrolysis and gasification. Gasification appears to be one of the best options. High temperature of gasification reaction destroys the potential BSE pathogens and produces gases which can be further used to produce valuable liquid chemicals by Fischer-Tropsch synthesis or to generate electricity. Gasification of meat and bone meal followed by thermal cracking/ reforming of tar was carried out using oxygen and steam separately at atmospheric pressure using a two-stage fixed bed reaction system in series. The first stage was used for the gasification and the second stage was used for thermal cracking/ reforming of tar.<p> Meat and bone meal was successfully gasified in the two-stage fixed bed reaction system using two different oxidants (oxygen and steam) separately. In gasification using oxygen, the effects of temperature (650 850 °C) of both stages, equivalence ratio (ER) (actual O2 supply/stoichiometric O2 required for complete combustion) (0.15 0.3) and the second stage packed bed height (40 100 mm) on the product (char, tar and gas) yield and gas (H2, CO, CO2, CH4, C2H4, C2H6, C3H6, C3H8) composition were studied. It was observed that the two-stage process increased hydrogen production from 7.3 to 22.3 vol. % (N2 free basis) and gas yield from 30.8 to 54.6 wt. % compared to single stage. Temperature and equivalence ratio had significant effects on the hydrogen production and product distribution. It was observed that higher gasification (850 °C) and cracking (850°C) reaction temperatures were favorable for higher gas yield of 52.2 wt. % at packed bed height of 60 mm and equivalence ratio of 0.2. The tar yield decreased from 18.6 wt. % to 14.2 wt. % and that of gas increased from 50.6 wt. % to 54.6 wt. % by changing the packed bed height of second stage from 40 to 100 mm while the gross heating value (GHV) of the product gas remained almost constant (16.2 16.5 MJ/m3).<p> In gasification using steam, effects of temperature (650 850 °C) of each stage, steam/MBM (wt/ wt) (0.4 -0.8), and packed bed height (40 -100 mm) in second stage on the product (Char, liquid and gas) distribution and gas (H2, CO, CO2, CH4, C2H4, other H/C) composition were studied. It was observed that higher reaction temperature (850 °C) was favorable for high gas and hydrogen yields. Char gasification improved from 27 to 13 wt. % and hydrogen yield increased from 36.2 to 49.2 vol. % with increase in steam/MBM (wt/ wt), while with increased in packed bed height increased gas (29.5 to 31.6 wt. %) and hydrogen (45 to 49.2 vol. %) yields. It didnt show substantial effect on heavier hydrocarbons.<p> The kinetic parameters for the pyrolysis of meat and bone meal were determined using thermogravimetric analysis (TGA) at three different heating rates (10, 15 and 25 °C/min) using distributed activation energy model (DAEM). The activation energy was found in the range of 60-246 kJ/mol for the temperature range of 496-758 K and their corresponding frequency factors were 6.63 x 103 to 8.7 x 1014 s-1.

Meat and bone meal (MBM) is a byproduct of the rendering industries. It is found to be responsible for the transmission of bovine spongiform encephalopathy (BSE) in animals and is no longer used as a feed to animals. There are various methods for disposal of MBM such as land filling, incineration, combustion, pyrolysis and gasification. Gasification appears to be one of the best options. High temperature of gasification reaction destroys the potential BSE pathogens and produces gases which can be further used to produce valuable liquid chemicals by Fischer-Tropsch synthesis or to generate electricity. Gasification of meat and bone meal followed by thermal cracking/ reforming of tar was carried out using oxygen and steam separately at atmospheric pressure using a two-stage fixed bed reaction system in series. The first stage was used for the gasification and the second stage was used for thermal cracking/ reforming of tar.<p> Meat and bone meal was successfully gasified in the two-stage fixed bed reaction system using two different oxidants (oxygen and steam) separately. In gasification using oxygen, the effects of temperature (650 850 °C) of both stages, equivalence ratio (ER) (actual O2 supply/stoichiometric O2 required for complete combustion) (0.15 0.3) and the second stage packed bed height (40 100 mm) on the product (char, tar and gas) yield and gas (H2, CO, CO2, CH4, C2H4, C2H6, C3H6, C3H8) composition were studied. It was observed that the two-stage process increased hydrogen production from 7.3 to 22.3 vol. % (N2 free basis) and gas yield from 30.8 to 54.6 wt. % compared to single stage. Temperature and equivalence ratio had significant effects on the hydrogen production and product distribution. It was observed that higher gasification (850 °C) and cracking (850°C) reaction temperatures were favorable for higher gas yield of 52.2 wt. % at packed bed height of 60 mm and equivalence ratio of 0.2. The tar yield decreased from 18.6 wt. % to 14.2 wt. % and that of gas increased from 50.6 wt. % to 54.6 wt. % by changing the packed bed height of second stage from 40 to 100 mm while the gross heating value (GHV) of the product gas remained almost constant (16.2 16.5 MJ/m3).<p> In gasification using steam, effects of temperature (650 850 °C) of each stage, steam/MBM (wt/ wt) (0.4 -0.8), and packed bed height (40 -100 mm) in second stage on the product (Char, liquid and gas) distribution and gas (H2, CO, CO2, CH4, C2H4, other H/C) composition were studied. It was observed that higher reaction temperature (850 °C) was favorable for high gas and hydrogen yields. Char gasification improved from 27 to 13 wt. % and hydrogen yield increased from 36.2 to 49.2 vol. % with increase in steam/MBM (wt/ wt), while with increased in packed bed height increased gas (29.5 to 31.6 wt. %) and hydrogen (45 to 49.2 vol. %) yields. It didnt show substantial effect on heavier hydrocarbons.<p> The kinetic parameters for the pyrolysis of meat and bone meal were determined using thermogravimetric analysis (TGA) at three different heating rates (10, 15 and 25 °C/min) using distributed activation energy model (DAEM). The activation energy was found in the range of 60-246 kJ/mol for the temperature range of 496-758 K and their corresponding frequency factors were 6.63 x 103 to 8.7 x 1014 s-1.

Recently, the meat supply chain has undergone a number of structural changes including increased concentration and a greater degree of quasi-vertical integration coordinated through contract procurement. The effects these changes have had on the meat supply chain, arranged as a complex array of producers, processors, distributors, and retailers, are not yet known. This study investigates the motives for, and consequences of, recent changes in the meat supply chain. The first essay examines causality among variables in the U.S. cattle supply chain using temporal and contemporaneous causality methodologies. Tests for structural changes reveal a likely structural change between later 1996 and early 1997 that was likely induced by the turnaround of the U.S. cattle inventory accompanied with severe droughts in Midwest. Results suggest that overall temporal causalities in the U.S. cattle supply chain become weaker after the structural change, though relatively strong causalities are found in pre-break periods. In contrast, strong contemporaneous causal relationships are founded in post-break periods. One conclusion is that recent structural changes in the industry are resulting in more rapid transmission of information through the supply chain. Causal evidence also suggests that the direction of information transmission has changed in recent times from moving generally downstream to moving generally upstream. This might be the result of increased concentration at the packer and retail levels giving rise to increased ability to “set” prices. The second essay develops a theoretical model to investigate the dynamic effects of the contract procurement on packer competition in the spot market with general contract pricing scheme. Results indicate that packers have an incentive to consider the effects of spot market purchases on contract procurement even after accounting for hedonic characteristics of live cattle and risk aversion in cattle feeding operations. The third essay investigates the impacts of domestic and overseas animal disease outbreaks on the Korean meat supply chain. Market impacts are investigated using both forecasts and historical decomposition of price innovations based on an error correction model (ECM) of the Korean meat sector. Results indicate that while the affected markets suffered significantly from the outbreaks, the impacts seem temporary and substitute meat markets benefited significantly.

Thesis (MSc (Paraclinical Sciences, Veterinary Science))--University of Pretoria, 2009. / Includes bibliographical references. Also available in print format.

Thesis (M.S.) in Food Science and Human Nutrition--University of Maine, 2001. / Includes vita. Advisory Committee: Denise Skonberg, Asst. Prof. of Food Science and Human Nutrition, Advisor; Alfred A. Bushway, Prof. of Food Science; Mary Ellen Camire, Prof. of Food Science and Human Nutrition; Robert Bayer, Prof. of Animal and Veterinary Sciences, Linda Kling, Assoc. Prof. of Animal and Veterinary Sciences. Bibliography: leaves 184-192.