Life-Cycle Inventory (LCI) Development for a Solid Waste/Coal Blend Gasification System for Production of Power and Chemicals
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Date
2002-10-13
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Abstract
To make good estimates of pollution prevention, performance, and cost of potentially promising new technologies, it is important to develop new assessment methodologies for managing technological development and for evaluating technologies. The research presented in this study is part of a larger effort to develop novel assessment methodologies for evaluation of the risks and potential pay-offs of new technologies that minimize or avoid pollutant production. The assessment methodology was demonstrated via a detailed case study of one promising pollution prevention technology – gasification of municipal solid waste (MSW), which was evaluated using a tiered approach including process simulation and life-cycle analysis (LCA).
In this study, an overall life-cycle inventory (LCI) model was developed for calculation of the LCI of the MSW/coal blend gasification system by combining the IGCC based polygeneration model, the refuse derived fuel (RDF) process model, the landfill process model, the conventional methanol process model, and the remanufacturing model. Specially, the development of the RDF process model was part of this research. Also, an existing LCI model was used for calculation of the LCI of the conventional mass burn waste to energy (WTE) system based on the WTE process model.
The gasification system was evaluated in two cases: a landfill with energy recovery and a landfill without energy recovery. Compared to a landfill without energy recovery, there is an environmental performance improvement for landfill with energy recovery. However, this improvement is negligible to the total LCI of the gasification system.
For both the gasification system and the WTE system, the emissions of most pollutants are negative due to the avoided emissions associated with electricity production, aluminum and ferrous recovery, and methanol production (gasification system only).
Compared to the WTE system, the gasification system has a better LCI for all the pollutants including atmospheric emissions, waterborne emissions, and solid waste emissions partly because more electricity was produced in the gasification system than the WTE system. Another reason is due to the production of methanol in the gasification system. The only exception is the BOD emissions, for which emissions associated with the MSW residual disposal in the landfill has a large contribution to its total emissions.
As the methanol plant size increases, the total emissions of the gasification system keep decreasing. Therefore, it is favorable for the gasification system to increase methanol production.
In this study, the avoided emissions associated with the sulfur recovery in the gasification were not included due to lack of data. Therefore, the total emissions of the gasification system were overestimated. Also, the effect of ammonia production on the LCI of the gasification system could not be evaluated in this study because the ammonia process model was not combined with the MSW/coal gasification system.
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IGCC, LCI, gasification, MSW, solid waste, methanol
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Degree
MS
Discipline
Civil Engineering
