scholarly journals Advanced exergy analysis of the natural gas liquid recovery process

2021 ◽  
pp. 311-311
Author(s):  
Fakhrodin Jovijari ◽  
Abbas Kosarineia ◽  
Mehdi Mehrpooya ◽  
Nader Nabhani
Keyword(s):  
Heat Exchanger ◽  
Natural Gas ◽  
Exergy Analysis ◽  
Recovery Process ◽  
Exergy Destruction ◽  
Analysis Method ◽  
System Improvement ◽  
Southwest Of Iran ◽  
Oil Company

Energy quality in each country is one of the important indicators of economic development, Which affects the economic growth of that country. Exergy analysis, considering all flow properties including pressure, temperature, composition, is a powerful way to evaluate the energy consumption of equipment such as natural gas and liquefied gas plants. Inefficiency of a system can be defined by the conventional exergy analysis method, While, irreversible resources and real potentials for system improvement can only be identified by the advanced exergy analysis method. This analysis splits conventional exergy destruction into two exogenous and endogenous parts according to origin, and also unavoidable and avoidable parts according to the ability to remove and modifications. In this method, the exergy concept was separated by considering the ideal and avoidable condition assumptions. As a real case study, a natural gas liquid plant 800, from National Iranian South Oil Company located in southwest of Iran was considered to be investigated by conventional exergy analysis, advanced exergy analysis methods. The results of conventional exergy analysis illustrated that the highest amount of exergy destruction belonged to compressor and heat exchanger with 509.99 and 629.04 kW, respectively. However, in the case of heat exchanger, despite having the highest rate of exergy destruction, it is not considered in modification priorities due to its low avoidable exergy destruction value. Also, advanced exergy analysis suggested that the exergy destruction of the compressor and heat exchanger will be reduced by improving performance of these components.

Thermodynamic Evaluation of a Direct Expansion Ground-Sourced Heat Pump with Horizontal Ground Heat Exchangers Using Advanced Exergy Analysis

2021 ◽  
Author(s):  
Abdolazim Zarei ◽  
Mehran Ameri ◽  
Hossein Ghazizade-Ahsaee
Keyword(s):  
Heat Exchanger ◽  
Heat Pump ◽  
Heat Exchangers ◽  
Exergy Analysis ◽  
Thermodynamic Evaluation ◽  
Ground Heat Exchanger ◽  
Exergy Destruction ◽  
Direct Expansion ◽  
Expansion Valve ◽  
System Improvement

This paper deals with the advanced exergetic analysis of a horizontal direct-expansion ground sourced CO2 heat pump operating in a transcritical cycle. The cycle is thermodynamically modeled in Engineering Equation Solver (EES) considering the pressure drops in both high and low temperature heat exchangers, and the system is to provide a fixed heating load. Conventional exergy analysis orderly suggests a compressor, expansion valve, gas cooler and ground heat exchanger to be considered for system improvement, while tracing exergy destruction of all components in detail demonstrates true improvement potential of each and all components and the system as a whole and offers a different order. Advanced exergy analysis points out that the compressor is directly and indirectly responsible for 56% of the overall exergy destruction generated in the cycle, confirming the detrimental role of this component in the system. The second influential component is recognized to be a ground heat exchanger accounting for 20% exergy destruction of the compressor as well as submitting 89% avoidability in its own exergy destruction, and expansion valve proves to be the last option for system improvement according to this analysis.

scholarly journals A case study on service recovery: Frontline employees’ perspectives and the role of empowerment

2016 ◽  
Vol 7 (2) ◽  
pp. 117-127 ◽  
Author(s):  
Satu Schumacher ◽  
Raija Komppula
Keyword(s):  
Content Analysis ◽  
Qualitative Case Study ◽  
Service Recovery ◽  
Recovery Process ◽  
Employee Empowerment ◽  
Frontline Employees ◽  
Analysis Method ◽  
Content Analysis Method

AbstractThe aim of this study was to improve our understanding of how frontline employees cope with service recovery situations and recover from them. It also takes a closer look at employee empowerment. This work represents a qualitative case study, and investigates the topic from the perspective of frontline employees. Data collection is implemented by interviewing the case hotel’s frontline personnel. A content analysis method was utilised to analyse the collected data. The findings suggest that the support of colleagues is more crucial in coping with service recovery situations and recovering from them than the support of managers. Personality traits also play a role. A theoretical scheme of the service recovery process from the perspective of frontline employees is developed from the analysis of the interviews. The findings indicate that written instructions would assist employees in service recovery situations.

On-Design and Off-Design Performance Analysis of a Gas Turbine Combined Cycle Using the Exergy Method

2000 ◽  
Author(s):  
Alcides Codeceira Neto ◽  
Pericles Pilidis
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Exergy Analysis ◽  
Pressure Ratio ◽  
Calorific Value ◽  
Combined Cycle ◽  
Exergy Destruction ◽  
Turbine Engine ◽  
Design Point

The present paper describes an on-design and an off-design performance study of gas turbine combined cycle based power plants. The exergy analysis has been carried out along with the performance assessment, considering the overall plant exergetic efficiency and the exergy destruction in the various components of the plant. The exergy method highlights irreversibility within the plant components, and it is of particular interest in this investigation. A computational analysis has been carried out to investigate the effects of compressor pressure ratio and gas turbine entry temperature on the thermodynamic performance of combined gas / steam power cycles. The exergy analysis has been performed for on-design point calculations, considering single shaft gas turbines with different compressor pressure ratios and turbine entry temperatures. Nearly 100 MW shaft power gas turbine engines burning natural gas fuel have been selected in this study. The off-design calculations have been performed for one of the gas turbines selected from the on-design point studies. For this particular gas turbine engine, fuel has been changed from natural gas to a low calorific value fuel gas originated from the gasification of wood. The exergy analysis indicates that maximum exergy is destroyed in the combustor, in the case of combined gas / steam cycles burning natural gas. For these studies on-design point, the exergy destruction in the combustor is found to decrease with increasing compressor pressure ratio to an optimum value and with increasing turbine entry temperature. In the off-design case the gas turbine engine is burning low calorific value fuel originated from the gasification of wood. The maximum exergy destruction occurs in the gasification process, followed by the combustion process in the gas turbine.

Exergy analysis of an ethylene refrigeration cycle integrated with a NGL recovery process for a large LNG train

2016 ◽  
Vol 56 (2) ◽  
pp. 606
Author(s):  
Nazreen Begum Najibullah Khan ◽  
Ahmed Barifcani ◽  
Moses Tade ◽  
Vishnu Pareek
Keyword(s):  
Natural Gas ◽  
Exergy Analysis ◽  
Minimum Energy ◽  
Recovery Process ◽  
Refrigeration Cycle ◽  
Aspen Hysys ◽  
Minimum Energy Consumption ◽  
Minimum Power Consumption ◽  
Plant Processing ◽  
Liquefaction Process

The natural gas liquefaction process consists of a sequence of refrigeration cycles that consumes a considerable amount of energy. The separation of natural gas (NG) from the natural gas liquids (NGL) is considered to be one of the significant parts in the liquefaction of natural gas, as this will influence the LNG product quality. The integration of NGL section with the liquefaction process is one of the fundamental ways to improve the efficiency of the process and provide economic benefit from operating and capital cost perspectives. In this extended abstract, two different configurations of NGL section integrated with the ethylene refrigeration cycle for the Cascade LNG plant—processing 5 million tonnes per annum (MTPA)—are proposed. The objectives of the proposed concepts are to meet the LNG higher heating value (HHV) specification and to achieve minimum power consumption for the refrigeration cycle. Exergy analysis is used as a thermodynamic tool to evaluate the efficiency of the process. The process was simulated using Aspen HYSYS and the results of the proposed configurations are presented and analysed. The proposed configurations can be used to produce LNG and NGL with minimum energy consumption.

Extended Exergy Analysis Based Comparison of Subcritical and Transcritical Refrigeration Systems

2016 ◽  
Vol 24 (02) ◽  
pp. 1650009 ◽  
Author(s):  
Jahar Sarkar ◽  
Dnyanesh Joshi
Keyword(s):  
Exergy Analysis ◽  
Vapor Compression ◽  
Exergy Destruction ◽  
Refrigeration System ◽  
Vapor Compression Refrigeration ◽  
System Improvement

The main purpose of this study is to apply advanced exergy analysis to the transcritical CO2 vapor compression refrigeration system, and compare with the analysis of subcritical cycle using ammonia and R404a. Endogenous, exogenous, avoidable and unavoidable exergy destructions are determined for each component of these systems. For CO2 system, compressor contributes highest avoidable endogenous exergy destruction and gas cooler contributes highest avoidable exogenous exergy destruction. It is concluded that compressor is the first component for CO2 and R404a, and evaporator is the first component for NH3 to be improved. System improvement options to reduce the exergy destruction are discussed as well.

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