Assessing Cogeneration Activity in Extraction–Condensing Steam Turbines: Dissolving the Issues by Applied Thermodynamics

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
Aviel Verbruggen ◽  
Jiří Jaromír Klemeš ◽  
Marc A. Rosen
Keyword(s):  
Investment Decision ◽  
Thermal Power ◽  
Numerical Data ◽  
Heat Extraction ◽  
Steam Turbines ◽  
Production Possibility Set ◽  
Expansion Path ◽  
Novel Method ◽  
Design Characteristics ◽  
Capacity Data

Extraction–condensing steam turbines mix cold-condensing and cogeneration activities making the respective power and fuel flows not directly observable. A flawed assessment of the flows is causing confusion and bias. A steam expansion path on a Mollier diagram reveals the design characteristics of a thermal power plant and of its embedded combined heat and power (CHP) activities. State variable data on a unit mass of steam, entering the turboset as life steam and leaving it at one of the heat extraction exhausts, provide the roster of the power-heat production possibility set of the plant. The actual production possibilities are drawn from the roster by applying capacity data and constraints on the heat extraction points. Design power-to-heat ratios of CHP activities are univocally identified, allowing accurate assessments of cogenerated power. This information is needed for proper incentive regulation of CHP activities, pursuing maximization of CHP quality and quantity. Quality is gauged by the power-to-heat ratio, principally a design (investment) decision. Quantity is gauged by the operational amounts of recovered heat exhausts. Optimal regulatory specificity is attained through setting generic frameworks by technology, accommodating investment and operational decisions by plant owners. Our novel method is explained and applied with numerical data, also revealing the flaws in present regulations.

A novel method for measuring the coarse water droplets in wet steam flow in steam turbines

2001 ◽  
Vol 10 (2) ◽  
pp. 123-126 ◽  
Author(s):  
Xiaoshu Cai ◽  
Lili Wang ◽  
Yongzhi Pan ◽  
Xin Ouyan ◽  
Jianqi Shen
Keyword(s):  
Steam Flow ◽  
Steam Turbines ◽  
Wet Steam ◽  
Water Droplets ◽  
Novel Method ◽  
Wet Steam Flow

Approximate Query Answering with Knowledge Hierarchy

2010 ◽  
pp. 189-203
Author(s):  
Wookey Lee ◽  
Myung-Keun Shin ◽  
Soon Young Huh ◽  
Donghyun Park ◽  
Jumi Kim
Keyword(s):  
Cost Model ◽  
Numerical Data ◽  
Query Answering ◽  
Query Relaxation ◽  
Approximate Query Answering ◽  
Novel Method ◽  
Approximate Query ◽  
Semantic Distances ◽  
Ranking Measures ◽  
Knowledge Hierarchy

Approximate Query Answering is important for incorporating knowledge abstraction and query relaxation in terms of the categorical and the numerical data. By exploiting the knowledge hierarchy, a novel method is addressed to quantify the semantic distances between the categorical information as well as the numerical data. Regarding that, an efficient query relaxation algorithm is devised to modify the approximate queries to ordinary queries based on the knowledge hierarchy. Then the ranking measures work very efficiently to cope with various combinations of complex queries with respect to the number of nodes in the hierarchy as well as the corresponding cost model.

Concept of Triple Heat Exchanger-Assisted Solar Pond Through an Improved Analytical Model

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Sunirmit Verma ◽  
Ranjan Das
Keyword(s):  
Analytical Model ◽  
Power Output ◽  
Heat Exchangers ◽  
Thermal Power ◽  
Convective Zone ◽  
Heat Extraction ◽  
Extraction System ◽  
Seepage Water ◽  
Solar Pond ◽  
Bottom Zone

A new three-zone heat extraction system and its analytical model for maximizing the thermal power output of salt gradient solar ponds against a given volume is proposed. The present study considers internal heat exchangers installed within the non-convective zone (NCZ), lower-convective zone (LCZ), and the ground below the pond. The work is validated against a simplified version of the model (eliminating ground and bottom-zone heat extractions) available in the existing literature. Contrary to the conventional practice of optimizing only the middle-zone pond thickness, here, the newly proposed expression is used to find ideal values of both the middle- and bottom-zone thicknesses of the pond along with its cross-sectional area. The present work acknowledges that although the three-zone heat extraction system is the best, yet if a choice for two-zone heat extraction is to be made between the NCZ–LCZ and ground–LCZ, then the former is a better alternative. The power output is observed to increase asymptotically with mass flow rates of the three heat exchangers. However, their values must lie much below their theoretical asymptotic limits and their selection is regulated by constructional and operational constraints. These involve a minimum pond depth to offset surface evaporation, ground seepage water loss, and constraints preventing turbulent flow in heat exchangers to reduce friction loss and pumping power. This work recommends using three heat exchangers instead of either one or two and provides cardinal guidelines to extract heat in an ideal manner for a fixed solar pond volume.

Experimental Study on Large Turbine HP-Valve’s Excitation Fault Caused by Steam’s Unsteady Flow and its Economic Solution

2014 ◽  
Vol 536-537 ◽  
pp. 1501-1509 ◽  
Author(s):  
Jie Wan ◽  
Jun Sheng Gu ◽  
Guo Rui Ren ◽  
Qian Guo ◽  
Zhi Hua Li ◽  
...  
Keyword(s):  
Large Scale ◽  
Thermal Power ◽  
Economic Loss ◽  
Random Fluctuation ◽  
Variable Load ◽  
Steam Turbines ◽  
Operation Condition ◽  
Valve Body ◽  
Power Generating Unit ◽  
Unit Depth

In order to stabilize the uncertainty of large-scale new energy power’s random fluctuation in the grid, there is an increasing number of large thermal power generating unit needing to do deep variable load operation. However, the pattern of steam inlet on turbine’s part load has a very significant impact on the unit operation condition of safety, stability and economy. In this paper the HP-valve’s body vibration fault of large steam turbines caused by unsteady steam flow under partial arc admission operating at part of their full load is researched, and an economic solution based on analysis and diagnosis of fault mechanism is provided by designing of complex HP-valve opening sequence rules. This solution solves the safety problem of valve vibration and avoids the economic loss by using full arc admission or replacing the valve body equipment directly, which is of great effective and practical verified by units’s actual operating experiment. As a result, it demonstrates that the optimization of HP-valve iadmission mode can not only change the stress state of high pressure rotor and prevent its vibration caused by the force of unbalanced flow to improve the shafting stability of the unit when running with variable load, but also can improve the steam instability and solve the resulting vibration problem in HP-valve. And it is of great engineering practical value to improve high-power thermal power unit depth secure efficient load operation.

Steam turbines of the T-50/60-8.8, K-63-8.8, and Tp-100/110-8.8 types destined for modernization of thermal power plants with K-50-90 and K-100-90 turbines

2012 ◽  
Vol 59 (12) ◽  
pp. 907-912 ◽  
Author(s):  
A. Ye. Valamin ◽  
A. Yu. Kultyshev ◽  
Yu. A. Sakhnin ◽  
M. V. Shekhter ◽  
M. Yu. Stepanov
Keyword(s):  
Power Plants ◽  
Thermal Power ◽  
Thermal Power Plants ◽  
Steam Turbines

Improving the Financial Performance of Concentrating Solar Thermal Power

2014 ◽  
Author(s):  
Andrew C. Beath ◽  
Brian Webby ◽  
Mehdi Aghaei Meybodi
Keyword(s):  
Cost Reduction ◽  
Financial Analysis ◽  
Negative Impact ◽  
Investment Decision ◽  
Thermal Power ◽  
Solar Thermal ◽  
Electricity Production ◽  
Cost Estimates ◽  
Electricity Cost ◽  
Investment Decision Making

Commercial-scale implementation of concentrating solar thermal (CST) technologies for electricity generation has been increasing worldwide, but technology assessments produced by engineering consultancies typically indicate that electricity production using CST is more expensive than most other renewable energy technologies. A review of a selection of costing studies that have been prepared in recent years for Australian government and industry bodies suggests that electricity cost estimates for CST technologies are exaggerated by a combination of high capital cost estimates and the financial analysis methods used. The results of these assessments are often used in investment decision-making processes of industry and government bodies, so this may have a negative impact on further development of CST technologies. While it is apparent that revision of the methods used in these analyses could improve the apparent cost effectiveness of CST, it is also apparent that the competitiveness of CST technologies needs to be improved through cost reduction and generation improvement. One major driver for this is that some CST technologies have the capability to efficiently store energy in thermal form for electricity production on demand and this could have significant benefits to both specific users and to the general electricity network stability. As a stage in identifying potential targets for new research that will improve competitiveness of CST technologies, a sensitivity analysis was performed to examine the influence of a broad range of factors on the cost of electricity using combined performance modeling and financial analysis. This largely reconfirms the commonly held view that reduction of solar collector costs is a critical target, but also identifies the importance of improving the performance of the overall power generation cycle and general cost reduction throughout the plants.

Transpulmonary hypothermia: A novel method of rapid brain cooling through augmented heat extraction from the lungs

Resuscitation ◽  
2014 ◽  
Vol 85 (10) ◽  
pp. 1405-1410 ◽  
Author(s):  
Matthew M. Kumar ◽  
Andrew D. Goldberg ◽  
Markos Kashiouris ◽  
Lawrence R. Keenan ◽  
Alejandro A. Rabinstein ◽  
...  
Keyword(s):  
Heat Extraction ◽  
Brain Cooling ◽  
Novel Method

scholarly journals Effect of insider trading on stock characteristics

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Sudipta Kumar Nanda ◽  
Parama Barai
Keyword(s):  
Insider Trading ◽  
Abnormal Return ◽  
Investment Decision ◽  
Least Square ◽  
Content Type ◽  
Insider Trades ◽  
Different Types ◽  
Abnormal Volume ◽  
Novel Method ◽  
The Relationship

PurposeThis paper investigates if investors consider legal insider trading data while making investment decisions. If any investment decision is based on insider transactions, then it will result in abnormal stock characteristics. The purpose of this paper is to investigate if insider trading affects stock characteristics like price, return and volume. The paper further investigates the effect on stock characteristics after the trade of different types of insiders and the relationship between abnormal return and abnormal volume.Design/methodology/approachThe study uses the event study method to measure the abnormal price, return and volume. Two-stage least square regression is used to investigate the relationship between abnormal return and abnormal volume.FindingsThe insider trades affect price, return and volume. The results are identical for both buy and sell transactions. The trades of different types of insiders have diverse effects on stock characteristics. The trades of substantial shareholders give rise to the highest abnormal price and return, whereas the promoters' trades result in the highest abnormal volume. No relationship is detected between abnormal return and volume.Originality/valueA novel method to calculate the abnormal price is proposed. The effect of trading of all types of insiders on stock characteristics is analyzed. The relationship between abnormal return and abnormal volume, after an insider trade, is investigated.

Technical Evaluation and Applications of Heat Recovery From Simple Cycle Gas Turbine Exhaust Systems

2020 ◽  
Author(s):  
Bouria Faqihi ◽  
Fadi A. Ghaith
Keyword(s):  
Pressure Drop ◽  
Gas Turbine ◽  
Heat Recovery ◽  
Power Plants ◽  
Thermal Power ◽  
Combined Cycle ◽  
Heat Extraction ◽  
Simple Cycle ◽  
System Pressure ◽  
Exhaust Heat

Abstract In the Gulf Cooperation Council region, approximately 70% of the thermal power plants are in a simple cycle configuration while only 30% are in combined cycle. This high simple to combined cycle ratio makes it of a particular interest for original equipment manufacturers to offer exhaust heat recovery upgrades to enhance the thermal efficiency of simple cycle power plants. This paper aims to evaluate the potential of incorporating costly-effective new developed heat recovery methods, rather than the complex products which are commonly available in the market, with relevant high cost such as heat recovery steam generators. In this work, the utilization of extracted heat was categorized into three implementation zones: use within the gas turbine flange-to-flange section, auxiliary systems and outside the gas turbine system in the power plant. A new methodology was established to enable qualitative and comparative analyses of the system performance of two heat extraction inventions according to the criteria of effectiveness, safety and risk and the pressure drop in the exhaust. Based on the conducted analyses, an integrated heat recovery system was proposed. The new system incorporates a circular duct heat exchanger to extract the heat from the exhaust stack and deliver the intermediary heat transfer fluid to a separate fuel gas exchanger. This system showed superiority in improving the thermodynamic cycle efficiency, while mitigating safety risks and avoiding undesired exhaust system pressure drop.

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