Giuseppina Di Lorenzo

Energy Efficiency and Environmental Life Cycle Assessment of Jatropha for Energy in Nigeria: A “Well-to-Wheel” Perspective

There is a large imbalance between demand and supply of energy in Nigeria, with inefficient power supply being the country’s greatest economic bane. Aside energy crisis, fuel is a luxurious commodity and petroleum diesel is the predominant fuel for power generation, particularly in the industrial sector. As a result, the country suffers from forced power outages, and persistent black out while residents and industries are forced to depend on self-generated electricity. These have notably reduced industrialization and increased environmental pollution across the country. This paper proposes the use of Jatropha biodiesel as a substitute fuel to petroleum diesel. It examines the energy efficiency and environmental life cycle impact of the production and use of 1MJ of Jatropha biodiesel in a typical 126 MW (ISO rating) industrial gas turbine power plant with multi-fuel capability using life cycle assessment methodologies and principles. A net energy ratio of 2.37, 1.54, and 1.32 and fossil fuel savings of 58%, 36% and 27% were achievable under three farming system scenarios: a) base-case rain-fed, b) base-case irrigated and c) large scale farming system. Also, an environmental benefit with GHG savings of 19% was attainable under the three farming scenarios. The results demonstrate that the contribution of GHGs and effect on climate change is most significant with the end use of the fuel. It also highlights the importance of clear definition of the reference system which should be indicative of the local production system and comparative to the system under study. A favourable business and economic climate driven by demand is proposed for Independent Power Producer (IPP) to generate power for off-grid users instead of generating power for the national grid using a decentralized Jatropha biodiesel production system coupled to waste to energy technologies.This could significantly improve the energy situation; diversify the energy generation mix and fuel supply in Nigeria, especially for small-scale businesses and the rural population.Copyright

Application of Bio-fAEG: A Biofouling Assessment Model in Gas Turbines and the Effect of Degraded Fuels on Engine Performance Simulations

The recent advances for flexible fuel operation and the integration of biofuels and blends in gas turbines raise concern on engine health and quality. One of such potential threats involves the contamination and the growth of microorganisms in fuels and fuel systems with consequential effect on engine performance and health. In the past, the effects of microbial growth in fuels have been qualitatively described; however their effects in gas turbines have not necessarily been quantified. In this paper, the effects of fuel deterioration are examined on a simulated aero-derivative gas turbine. A diesel-type fuel comprising of thirteen (13) hydrocarbon fractions was formulated and degraded with Bio-fAEG, a bio fouling assessment model that defines degraded fuels for performance simulation and analysis, predicts biodegradation rates as well as calculates the amount of water required to initiate degradation under aerobic conditions. The degraded fuels were integrated in the fuel library of Turbomatch (v2.0) and a twin shaft gas turbine was modeled for fuel performance analysis. The results indicate a significant loss in performance with reduced thermal efficiency of 1% and 10.4% and increased heat rate of 1% and 11.6% for the use of 1% and 10% degraded fuels respectively. Also parameters such as exhaust gas temperature and mass flow deviated from the baseline data indicating potential impact on engine health. Therefore, for reliable and safe operation, it is important to ensure engines run on good quality of fuel.This computational study provides insights on fuel deterioration in gas turbines and how it affects engine health.Copyright

A Framework for the Evaluation of Investments in Clean Power-Technologies

Abstract A decision-support framework has been developed to evaluate options for reducing carbon-dioxide emissions from the power-generation sector. The framework is based on the so-called T.E.R.A. (Techno-economic environmental risk analysis) method conceived at Cranfield University. It is based essentially on a robust power-plant performance model, coupled with a variety of additional modules (emissions, economic, technology-risk analysis). The evaluation tool performs screening over multiple options by means of modelling and assessment of several metrics that represent possible advantages and risks for a given assessment case. A case study on a CCS-based technology is reported to illustrate the application of the framework.

The Development of a Model for the Assessment of Bio-Fouling in Gas Turbine System

A significant problem encountered in the gas turbine industry with fuel products is the degradation of fuel and fuel systems by microorganisms, which are largely bacteria, embedded in biofilms. These microorganisms cause system fouling and other degradatory effects, extending often to sudden failure of components with cost implications. Current methods of assessment are only post-impact evaluation and do not necessarily quantify the effects of fuel degradation on engine performance and emission. Therefore, effective models that allow predictive condition monitoring are required for engine’s fuel system reliability, especially with readily biodegradable biofuels. The aim of this paper is to introduce the concept of bio-fouling in gas turbines and the development of a bio-mathematical model with potentials to predict the extent and assess the effects of microbial growth in fuel systems. The tool takes into account mass balance stoichiometry equations of major biological processes in fuel bio-fouling. Further development, optimization and integration with existing Cranfield in-house simulation tools will be carried out to assess the overall engine performance and emission characteristics. This new tool is important for engineering design decision, optimization processes and analysis of microbial fuel degradation in gas turbine fuels and fuel systems.© 2013 ASME

Supporting the development of advanced low-carbon power plants: Risk analysis and TRL concept

CO2 emissions reduction has become a major issue for the power generation sector. Advanced technology development and deployment are among the most frequently advocated keys to solving this great challenge, since the present configurations are unlikely to meet the demanding environmental requirements. This paper presents a methodical approach intended to evaluate the maturity level and the future development potential of environmental friendly power plants coupling Monte Carlo simulation technique and the concept of Technology Readiness Level (TRL). Although the numerical results are speculative, the paper offers insights into the validity of the method proposed as a means to addressing the role of technological innovation in the power generation sector to meet global climate stability targets.