scholarly journals Energy-Saving Strategies and their Energy Analysis and Exergy Analysis for In Situ Thermal Remediation System of Polluted-Soil

Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 4018 ◽  
Author(s):  
Tian-Tian Li ◽  
Yun-Ze Li ◽  
Zhuang-Zhuang Zhai ◽  
En-Hui Li ◽  
Tong Li
Keyword(s):  
Energy Saving ◽  
Exergy Analysis ◽  
Energy Analysis ◽  
Waste Heat ◽  
Polluted Soil ◽  
Severe Problem ◽  
Industrial Soil ◽  
Thermal Remediation ◽  
Variable Condition

The environmental safety of soil has become a severe problem in China with the boost of industrialization. Polluted-soil thermal remediation is a kind of suitable remediation technology for large-scale heavily contaminated industrial soil, with the advantages of being usable in off-grid areas and with a high fuel to energy conversion rate. Research on energy-saving strategies is beneficial for resource utilization. Focused on energy saving and efficiency promotion of polluted-soil in situ thermal remediation system, this paper presents three energy-saving strategies: Variable-condition mode (VCM), heat-returning mode (HRM) and air-preheating mode (APM). The energy analysis based on the first law of thermodynamics and exergy analysis based on the second law of thermodynamics are completed. By comparing the results, the most effective part of the energy-saving strategy for variable-condition mode is that high savings in the amount of natural gas (NG) used can be achieved, from 0.1124 to 0.0299 kg·s−1 in the first stage. Energy-saving strategies for heat-returning mode and air-preheating mode have higher utilization ratios than the basic method (BM) for the reason they make full use of waste heat. As a whole, a combination of energy-saving strategies can improve the fuel savings and energy efficiency at the same time.

Discussion of Energy Consumption Analysis Method on Energy System

2011 ◽  
Vol 130-134 ◽  
pp. 1578-1581
Author(s):  
Cai Juan Zhang ◽  
Li Gang Wang ◽  
Ling Nan Wu ◽  
Tong Liu ◽  
Qiang Lu ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Economic Analysis ◽  
Energy Saving ◽  
Exergy Analysis ◽  
Energy Analysis ◽  
Rapid Development ◽  
Second Law Of Thermodynamics ◽  
Energy Utilization ◽  
Second Law ◽  
Analysis Method

With the social rapid development, the earth's limited primary energy such as coal, oil, natural gas etc will be exhausted; energy problem has caused worldwide widespread attention. Therefore, under the development of renewable energy, without exception, each country is actively trying to explore the new theory and using energy-saving and technology to improve energy utilization ratio and reduce the energy consumption and the harm on environment. Scientific analysis of energy saving is an important link of digging energy saving potential, effective energy analysis method plays a pivotal role in implementing saving energy. This paper summarized several energy analysis methods on the basis of the first and second law of thermodynamics, introduced the most widely used enthalpy analysis method, entropy analysis, exergy analysis and exergy economic analysis which are based on the second law of thermodynamics, introduced emphatically the specific consumption analysis theory development with exergy analysis and exergy economic analysis.

scholarly journals Conventional and Advanced Exergoeconomic Analysis of a Compound Ejector-Heat Pump for Simultaneous Cooling and Heating

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3511
Author(s):  
Ali Khalid Shaker Al-Sayyab ◽  
Joaquín Navarro-Esbrí ◽  
Victor Manuel Soto-Francés ◽  
Adrián Mota-Babiloni
Keyword(s):  
Heat Pump ◽  
Exergy Analysis ◽  
Waste Heat ◽  
District Heating ◽  
Cost Comparison ◽  
Exergy Destruction ◽  
Pump System ◽  
Heat Pump System ◽  
Destruction Rate ◽  
Exergoeconomic Analysis

This work focused on a compound PV/T waste heat driven ejector-heat pump system for simultaneous data centre cooling and waste heat recovery for district heating. The system uses PV/T waste heat as the generator’s heat source, acting with the vapour generated in an evaporative condenser as the ejector drive force. Conventional and advanced exergy and advanced exergoeconomic analyses are used to determine the cause and avoidable degree of the components’ exergy destruction rate and cost rates. Regarding the conventional exergy analysis for the whole system, the compressor represents the largest exergy destruction source of 26%. On the other hand, the generator shows the lowest sources (2%). The advanced exergy analysis indicates that 59.4% of the whole system thermodynamical inefficiencies can be avoided by further design optimisation. The compressor has the highest contribution to the destruction in the avoidable exergy destruction rate (21%), followed by the ejector (18%) and condenser (8%). Moreover, the advanced exergoeconomic results prove that 51% of the system costs are unavoidable. In system components cost comparison, the highest cost comes from the condenser, 30%. In the same context, the ejector has the lowest exergoeconomic factor, and it should be getting more attention to reduce the irreversibility by design improving. On the contrary, the evaporator has the highest exergoeconomic factor (94%).

Study on Energy Consumption Analysis Method of Distributed Cryogenic Separation System

2013 ◽  
Vol 732-733 ◽  
pp. 52-56
Author(s):  
Zhi Guo Wang ◽  
Lei Zhang ◽  
Chai Ling Yin
Keyword(s):  
Energy Use ◽  
Exergy Analysis ◽  
Waste Heat ◽  
Engineering Practice ◽  
Analysis Method ◽  
Analysis Model ◽  
Two Stage ◽  
Separation Plant ◽  
Flow Energy ◽  
Saving Effect

Cryogenic separation method is the main method to recycle NGL (Natural Gas Liquid). Oilfield two-stage expansion NGL cryogenic separation plant is a complex system composed of varieties of material flow, energy flow and equipments, is a typical distributed energy use system composed of three parts, energy supply, energy use and waste heat recovery. In this paper, according to the process characteristics of two-stage expansion cryogenic separation plant, three-box analysis method was used, the system was compartmentalized into six subsystems, represented the exergy analysis model of system—unit—equipment, given the specific analysis process and the assessment rules for the NGL system. Using the practical operational data, the writers conduct the exergy analysis on the operational working condition of Daqing oilfield NGL system. Based on the calculation results, this paper raises some proposals to improve the operational efficiency, and achieved a good energy saving effect in engineering practice.

Two-stage in situ gas stripping for enhanced butanol fermentation and energy-saving product recovery

2013 ◽  
Vol 135 ◽  
pp. 396-402 ◽  
Author(s):  
Chuang Xue ◽  
Jingbo Zhao ◽  
Fangfang Liu ◽  
Congcong Lu ◽  
Shang-Tian Yang ◽  
...  
Keyword(s):  
Energy Saving ◽  
Product Recovery ◽  
Gas Stripping ◽  
Two Stage ◽  
Butanol Fermentation

Energy and Exergy Waste Heat Recovery Analysis of a Bulk Carrier Main Diesel Engine Equipped with Dual-Loop Organic Rankine Cycle

2021 ◽  
Author(s):  
Elias A. Yfantis ◽  
Efthymios G. Pariotis ◽  
Theodoros C. Zannis ◽  
Konstantina Asimakopoulou
Keyword(s):  
Diesel Engine ◽  
Energy Analysis ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Ambient Conditions ◽  
Bulk Carrier ◽  
Operational Profile ◽  
Exhaust Heat ◽  
Marine Diesel

The energy and the exergy performance of a dual-loop Organic Rankine Cycle (ORC), which harvests exhaust heat from a two-stroke slow-speed main marine diesel engine of a bulk carrier is examined herein. An energy analysis is adopted to calculate the energy flows to the components of the high-temperature (HT) and the low-temperature (LT) loops of the bottoming ORC and through them, to calculate the energy efficiency of the ORC and the generated power from both expanders. Also, an exergy analysis is implemented to predict the irreversibility rates of the components of both HT and LT loops of the ORC system. Various organic fluids are examined for the HT and the LT ORC loops and the optimum combination is selected based on the results of a parametric analysis. The effect of ambient conditions on the energetic and exergetic performance of the dual-loop ORC is examined. The energy analysis of the bottoming dual-loop ORC is projected to a specific mission operational profile of a bulk carrier for predicting the benefits in fuel cost saving and CO2 and SO2 emission reduction compared to conventional vessel operation.

scholarly journals Comparative studies of Cu-Cl Thermochemical Water Decomposition Cyles for Hydrogen Production

2018 ◽  
Vol 61 ◽  
pp. 00009
Author(s):  
Funmilayo Osuolale ◽  
Oladipupo Ogunleye ◽  
Mary Fakunle ◽  
Abdulfataah Busari ◽  
Yetunde Abolanle
Keyword(s):  
Hydrogen Production ◽  
Exergy Analysis ◽  
Energy Analysis ◽  
Chemical Species ◽  
Efficiency Improvement ◽  
Water Decomposition ◽  
Step Cycle ◽  
Efficiency Increase ◽  
Production Stages ◽  
Parametric Studies

This research focuses on thermodynamic analysis of the copper chlorine cycles. The cycles were simulated using Aspen Plus software. All thermodynamic data for all the chemical species were defined from literature and the reliability of other compounds in the simulation were ascertained. The 5-step Cu–Cl cycle consist of five steps; hydrolysis, decomposition, electrolysis, drying and hydrogen production. The 4-step cycle combines the hydrolysis and the drying stage of the 5-step cycle to eliminate the intermediate production and handling of copper solids. The 3-step cycle has hydrolysis, electrolysis and hydrogen production stages. Exergy and energy analysis of the cycles were conducted. The results of the exergy analysis were 59.64%, 44.74% and 78.21% while that of the energy analysis were 50%, 49% and 35% for the 5-step cycle, 4-step cycle and 3-step cycle respectively. Parametric studies were conducted and possible exergy efficiency improvement of the cycles were found to be between 59.57-59.67%, 44.32-45.67% and 23.50-82.10% for the 5-step, 4-step and 3-step respectively. The results from the parametric analysis of the simulated process could assist ongoing efforts to understand the thermodynamic losses in the cycle, to improve efficiency, increase the economic viability of the process and to facilitate eventual commercialization of the process.

The Energy-Saving Diagnosis of PWR Nuclear Power Station Based on the Thermo-Economic Analysis Model

2010 ◽  
Author(s):  
Juan Chen ◽  
Tao Zhou ◽  
Ke Ran
Keyword(s):  
Graph Theory ◽  
Economic Analysis ◽  
Energy Saving ◽  
Nuclear Power Station ◽  
Nuclear Power ◽  
Exergy Analysis ◽  
Performance Estimation ◽  
Structure Theory ◽  
Analysis Model ◽  
Power Station

Exergy analysis model of PWR nuclear power station is developed in which signal flowing graph theory is introduced to set up the relation equations between input exergy flow and output exergy flow. Then, combining with resource distribution between different components, thermo-economic analysis model is obtained by setting up unit thermo-economic cost equations of different components with productive structure graph. Taking Daya Bay as an example, exergy analysis and thermal-economic analysis are put forward with detailed distribution of exergy and investment cost. Finally, aimed at energy-saving, static diagnosis is performed in two levels: energy conservation and cost reduction, and on this basis dynamic diagnosis is developed through sensitivity analysis considering different influence factors such as main steam temperature, fuel price, construction capital investment, post treatment cost and so on. The introduction of signal flow graph theory and thermal-economic structure theory is helpful to do performance estimation with high speed and good accuracy. It provides a new way for rapid optimization and offers an effective theoretical method for energy-saving of PWR nuclear power station including advanced reactor such as AP1000.

scholarly journals Thermo-economic analysis of an efficient lignite-fired power system integrated with flue gas fan mill pre-drying

2018 ◽  
Author(s):  
Junjie Yan ◽  
Xiaoqu Han ◽  
Jiahuan Wang ◽  
Ming Liu ◽  
Sotirios Karellas
Keyword(s):  
Moisture Content ◽  
Economic Analysis ◽  
Power System ◽  
Energy Saving ◽  
Flue Gas ◽  
Power Plants ◽  
Waste Heat ◽  
Low Rank ◽  
Analysis Model ◽  
Energy Saving Potential

Lignite is a domestic strategic reserve of low rank coals in many countries for its abundant resource and competitive price. Combustion for power generation is still an important approach to its utilization. However, the high moisture content always results in low efficiencies of lignite-direct-fired power plants. Lignite pre-drying is thus proposed as an effective method to improve the energy efficiency. The present work focuses on the flue gas pre-dried lignite-fired power system (FPLPS), which is integrated with fan mill pulverizing system and waste heat recovery. The thermo-economic analysis model was developed to predict its energy saving potential at design conditions. The pre-drying upgrade factor was defined to express the coupling of pre-drying system with boiler system and the efficiency improvement effect. The energy saving potential of the FPLPS, when applied in a 600 MW supercritical power unit, was determined to be 1.48 %-pts. It was concluded that the improvement of boiler efficiency mainly resulted from the lowered boiler exhaust temperature after firing pre-dried low moisture content lignite and the lowered dryer exhaust gas temperature after pre-heating the boiler air supply. Keywords: lignite; pre-drying; thermodynamic analysis; thermo-economics

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