2 resultados para genesis of coal

em QSpace: Queen's University - Canada


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A recently developed novel biomass fuel pellet, the Q’ Pellet, offers significant improvements over conventional white pellets, with characteristics comparable to those of coal. The Q’ Pellet was initially created at bench scale using a proprietary die and punch design, in which the biomass was torrefied in-situ¬ and then compressed. To bring the benefits of the Q’ Pellet to a commercial level, it must be capable of being produced in a continuous process at a competitive cost. A prototype machine was previously constructed in a first effort to assess continuous processing of the Q’ Pellet. The prototype torrefied biomass in a separate, ex-situ reactor and transported it into a rotary compression stage. Upon evaluation, parts of the prototype were found to be unsuccessful and required a redesign of the material transport method as well as the compression mechanism. A process was developed in which material was torrefied ex-situ and extruded in a pre-compression stage. The extruded biomass overcame multiple handling issues that had been experienced with un-densified biomass, facilitating efficient material transport. Biomass was extruded directly into a novel re-designed pelletizing die, which incorporated a removable cap, ejection pin and a die spring to accommodate a repeatable continuous process. Although after several uses the die required manual intervention due to minor design and manufacturing quality limitations, the system clearly demonstrated the capability of producing the Q’ Pellet in a continuous process. Q’ Pellets produced by the pre-compression method and pelletized in the re-designed die had an average dry basis gross calorific value of 22.04 MJ/kg, pellet durability index of 99.86% and dried to 6.2% of its initial mass following 24 hours submerged in water. This compares well with literature results of 21.29 MJ/kg, 100% pellet durability index and <5% mass increase in a water submersion test. These results indicate that the methods developed herein are capable of producing Q’ Pellets in a continuous process with fuel properties competitive with coal.

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The Cape Breton Development Corporation need not, should not, be dying in the way it is. “Devco” has been widely represented as a failure dragged out too long. In fact it had for a time considerable success in a role too difficult to be often attempted. The main failure was in the political will to stick to its purpose. This commentary is in three parts. The first, major section discusses the purpose of Devco and the policies that served the purpose quite well but were maintained for little more than a decade. It suggests that the benefits would have been greater if Devco had been started earlier in the period of postwar prosperity. The second section comments on the enfeeblement of Devco in the 1980s. The removal of its development function also weakened, and has eventually led to the abandonment of, Devco’s social purpose in the operation of coal mining. Third, a short epilogue pointing out that, while the Cape Breton case is extreme, there will be increasing need to moderate the socially disruptive consequences of accelerating economic change. There are lessons from the Devco experience: the longer remedial action is delayed, the more difficult and expensive it becomes, and the more necessary for its effectiveness is a steady political will.