Midway evaluation in Mechanical Engineering - Sahar Safarianbana

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Title: Modeling of small scale municipal solid-waste gasification system for energy production

Doctoral candidate: Sahar Safarianbana

Doctoral committee:
Rúnar Unnþórsson, Professor at the Faculty of Industrial Engineering, Mechancial Engineering and Computer Science, University of Iceland
Christiaan Petrus Richter, Professor at the Faculty of Industrial Engineering, Mechancial Engineering and Computer Science, University of Iceland
Jukka Taneli Heinonen, Professor at the Faculty of Civil and Environmental Engineering, University of Iceland

Abstract:

Recently, several waste incinerators in Iceland were closed due to toxic dioxins from their emissions polluting soil and ending up in meat and milk products. No cost effective and environmentally option has been found to date. So, huge amounts of waste are transported by ferry and road to be landfilled or incinerated. This project aims at adapting green solution for waste disposal to Iceland. The process is called green sustainable gasification technology which is a waste-to-energy system that not only involves wastes as fuel but also helps in reduction of releasing pollutant.
The challenges for local waste gasification are its adaption to the Icelandic scale, feedstock, and operational parameters. Downscaling must be done while still eliminating the pollution problems of incinerators and the cost constraints of small-scale plants. In fact, gasification’s potential has been proved in medium-scale facilities but there are only a few successful small-scale studies in the literature. The admissible range of feedstock properties is narrow for each gasifier design, because the chemistry and performance of gasification are very sensitive to variations in feedstock composition, moisture, and ash content. Variation in properties has a major impact on the performance, cost, and feasibility of a system. Moreover, various operational parameters, such as temperature, equivalence ratio, steam injection, air-flow rate etc., have different effects on syngas composition and efficiency.
To overcome these challenges, a simulation tool needs to be used to model the integrated gasification system from pre-processing to pyrolysis, combustion and gasification and post-processing like power production unit. This model helps to understand whether, under what conditions and in which ways the system can operate. In fact, development of a simulation model as a main step speeds up the process of finding feasible feedstocks and optimal conditions, as it is impractical to test every condition and material in experiments.

Sahar Safarianbana, for her PhD, is working on developing a simulation model of small-scale gasification systems for energy production. In this lecture she will cover the challenges of developing practical simulation models for small-scale waste biomass gasification and present about effect of various inputs and conditions on the system performance. She developed an advanced simulation model for small-scale waste biomass gasification by using ASPEN Plus. Then the model was used for comparative analysis of the gasification performance of organic wastes under various operating conditions. Moreover, she has carried out, an environmental assessment and techno-economic analysis of the small-scale waste biomass gasification to propose a sustainable waste to power system adapted with conditions in Iceland.