Tatiana Morosuk

Understanding the Formation of Costs and Environmental Impacts Using Exergy-Based Methods

We examine the integrated advanced exergetic, exergoeconomic, and exergoenvironmental analyses, which identify the magnitude, location and causes of thermodynamic inefficiencies, costs, and environmental impacts. The analyses evaluate the interactions among the components of the overall system and the real potential for improving a system component. The results from the application of these methods are useful in understanding the operation of energy conversion systems and in developing strategies to improve them. This chapter demonstrates how exergoeconomic and exergoenvironmental analyses provide the user with information related to (a) the formation processes of costs and environmental impacts, and (b) the interactions among thermodynamics, economics, and ecology.

Evaluation of a Novel Concept for LNG Regasification in an Industrial Complex

New technologies that lead to an increased efficiency and lower product cost in each step of the LNG chain are of particular interest to scientists and engineers. The studies and commercial applications of LNG regasification processes can be divided into three large groups: (a) direct and indirect heat transfer processes between LNG and other substances in the so-called “traditional systems”, (b) LNG-based electricity generation systems, and (c) LNG regasification within an industrial complex consisting of an LNG import terminal and at least one different refrigeration or cryogenic plant (process).In this paper the regasification of LNG is accomplished within an air separation process, to improve the overall system efficiency. The paper discusses the simulation, and the energetic, exergetic, and economic analyses of this novel cryogenic-based concept, which is characterized by a lower specific power requirement and improved cost effectiveness.Copyright

Assessment of a Power Plant With CO2 Capture Using an Advanced Exergoenvironmental Analysis

This paper presents an evaluation of the environmental performance of an advanced zero emission plant (AZEP) including CO2 capture. The evaluation is conducted with the aid of an advanced exergoenvironmental analysis. The results are compared with those of a reference combined-cycle power plant without CO2 capture. Advanced exergy-based methods are used to (a) quantify the potential for improving individual components or overall systems, and (b) reveal detailed interactions among components—two features not present in conventional analyses, but very useful, particularly when evaluating complex systems. In an advanced exergoenvironmental analysis, the environmental impacts calculated in a conventional exergoenvironmental analysis are split into avoidable/unavoidable (to evaluate the potential for component improvement) and endogenous/exogenous (to understand the interactions among components) parts. As in the reference plant, the potential for reducing the environmental impact of the AZEP has been found to be limited by the relatively low avoidable environmental impact associated with the thermodynamic inefficiencies of several of its components. However, although the environmental impacts for the majority of the components of the plant are related mainly to internal inefficiencies and component interactions are of secondary importance, there are strong interactions between the reactor and some other components.

Advanced Exergy Analysis Based on the Parametric Study of the Regasification of LNG Integrated Into an Air Separation Process

The growing demand for natural gas leads to an increasing LNG market. The amount of traded LNG has more than doubled during the last decade. This trend is intensified by the rising number of liquefaction plants (export terminals) and regasification plants (import terminals). At the end of the year 2013 there were 86 liquefaction plants in 17 exporting countries and 104 import terminals in 29 importing countries. Also the number of floating regasification plants is growing. It is expected that the LNG market will grow with 7 % per year until 2020. In comparison, the market for gaseous natural gas only will increase with approxematly 1.8 % per year. The difference could be led back to the several advantages, when using LNG. Thus LNG enables the extraction of natural gas in offsite areas and leads to a flexible gas market. Especially with improving the efficiency of each part of the LNG chain — liquefaction, transportation, storage and regasification — and its fallen prices the LNG market will continue to grow. For the regasification of LNG different processes have been used, while mainly the vaporization via direct or indirect heating is applied. Due to their location at the coast of the importing country, seawater, air or the combustion gases coming from natural gas are used as thermal energy. A further possibility is the combination of regasification of LNG with generating electricity. Additionally, the regasification of LNG could be integrated into chemical processes (oil refinery and petrochemical plants), where low temperature refrigeration is required. The authors have already reported a concept for the integration of the regasification of LNG into an air separation and liquefactions process, i.e. into a cryogenic processes. In previous publications, an evaluation of the conventional air separation unit in combination with the LNG regasification has been reported. It was emphasized that the integration of LNG leads to a lower power consumption for the entire system. This paper deals with an improved concept for integrating the regasification of LNG into an air separation process. Due to structural changes, comparing the first design and the new design, the system can be further improved from the thermodynamic point of view. The aim of this paper is to discover the potential for improvement by the parametric study. The results obtained from the sensitivity analysis (energetic and exergetic) are reported as well as the results obtained from the advanced exergetic analysis. Some options for new designs of this system are be developed.Copyright

LNG Regasification Integrated Within an Air-Separation Process

The liquefied natural gas (LNG) market has grown significantly and the growth is expected to continue in the future. New technologies that lead to an increased efficiency in each step of the LNG chain are currently under consideration. The studies and the commercial applications associated with the LNG regasification processes can be divided into three large groups: (a) Direct and indirect heat transfer processes between water and LNG; (b) LNG-based co-generation systems, and (c) industrial complexes consisting of an LNG import terminal and an energy-conversion plant, or an energy-intensive chemical plant.In this paper a novel concept for integrating the LNG vaporization into an air separation process is presented. The simulation, energy and exergy analyses are discussed.© 2014 ASME

Systems Generating Electricity Through Expansion of Natural Gas: Effect of the Ambient Temperature to the Performance

This paper discusses the thermodynamic performance of three different system configurations used to expand natural gas from a pressure of above 40 bar to a final pressure of approximately 12 bar: (1) System in which all natural gas passes through a throttling valve, (2) system that uses only an expander as the expansion device, and (3) system using in parallel both an expander and a throttling valve as expansion devices. The sensitivity analysis demonstrates how the mass flow rate of natural gas and the seasonal fluctuation of the ambient temperature affect the thermodynamic efficiency of these systems.Copyright

Exergoeconomic Evaluation of a Solid-Oxide Fuel-Cell-Based Combined Heat and Power Generation System

An exergoeconomic evaluation has been conducted for a 100kW-class SOFC power generation system, in order to evaluate the cost effectiveness of the system. The exergoeconomic analysis is an appropriate combination of an exergy analysis and an economic analysis. Through an exergoeconomic analysis, we obtain the real cost associated with each stream and component in a system. We also can calculate the portion of the cost that is associated with the exergy destruction within each component.The analyzed system, a 100kW SOFC power generation system, consists of SOFC stack, reformer, catalytic combustor, heat exchangers, pumps, blowers, inverter, and HRSG for heat recovery.As a first step, mass, energy, and exergy balances were formulated. Then a conventional exergetic analysis (based on the concept of exergy of fuel/exergy of product) was performed. Next, a levelized cost for each component was calculated based on the purchased equipment costs using the Total Revenue Requirement (TRR) method with appropriate economic assumptions. Finally, the cost structure of the SOFC was figured out through an exergoeconomic evaluation. Finally suggestions have been made for reducing the cost associated with the product of the system.Copyright