scholarly journals Study on Temperature Feedback Effect of Supercritical CO2–Cooled Reactor

2021 ◽  
Vol 9 ◽  
Author(s):  
Lianjie Wang ◽  
Di Lu ◽  
Lei Yao ◽  
Hongzhi Xiang ◽  
Chen Zhao
Keyword(s):  
Thermal Efficiency ◽  
Supercritical Co2 ◽  
Feedback Effect ◽  
Simple System ◽  
Type Reactor ◽  
The Poor ◽  
Temperature Feedback ◽  
New Type ◽  
Effects Of Temperature

As a potential new-type reactor, the supercritical CO2 (S-CO2)–cooled reactor has several advantages, such as being a simple system, having high thermal efficiency, having a small size, and being lightweight. Due to the poor neutronics moderation performance, the S-CO2–cooled reactor shows the disadvantage of a weak temperature feedback effect on reactivity. In this article, the neutronics performance of the reactor has been focused on, and the effects of temperature feedback on fuel, coolant, and moderator studied and the method to improve temperature feedback of the S-CO2 reactor proposed.

A Comparison Between ORC and Supercritical CO2 Bottoming Cycles For Energy Recovery From Industrial Gas Turbines Exhaust Gas

2021 ◽  
Author(s):  
M. A. Ancona ◽  
M. Bianchi ◽  
L. Branchini ◽  
A. De Pascale ◽  
F. Melino ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Supercritical Co2 ◽  
Energy Demand ◽  
Oil And Gas ◽  
Gas Production ◽  
Medium Size ◽  
Oil And Gas Production ◽  
Industrial Gas Turbines

Abstract Gas turbines are often employed in the industrial field, especially for remote generation, typically required by oil and gas production and transport facilities. The huge amount of discharged heat could be profitably recovered in bottoming cycles, producing electric power to help satisfying the onerous on-site energy demand. The present work aims at systematically evaluating thermodynamic performance of ORC and supercritical CO2 energy systems as bottomer cycles of different small/medium size industrial gas turbine models, with different power rating. The Thermoflex software, providing the GT PRO gas turbine library, has been used to model the machines performance. ORC and CO2 systems specifics have been chosen in line with industrial products, experience and technological limits. In the case of pure electric production, the results highlight that the ORC configuration shows the highest plant net electric efficiency. The average increment in the overall net electric efficiency is promising for both the configurations (7 and 11 percentage points, respectively if considering supercritical CO2 or ORC as bottoming solution). Concerning the cogenerative performance, the CO2 system exhibits at the same time higher electric efficiency and thermal efficiency, if compared to ORC system, being equal the installed topper gas turbine model. The ORC scarce performance is due to the high condensing pressure, imposed by the temperature required by the thermal user. CO2 configuration presents instead very good cogenerative performance with thermal efficiency comprehended between 35 % and 46 % and the PES value range between 10 % and 22 %. Finally, analyzing the relationship between capital cost and components size, it is estimated that the ORC configuration could introduce an economical saving with respect to the CO2 configuration.

Usability in the Context of e-Learning

2011 ◽  
pp. 121-144 ◽  
Author(s):  
Panagiotis Zaharias
Keyword(s):  
Instructional Design ◽  
Adult Learners ◽  
End Users ◽  
Usability Evaluation ◽  
Design Parameters ◽  
Motivation To Learn ◽  
The Poor ◽  
E Learning ◽  
New Type ◽  
Usability Evaluation Methods

The issue of e-learning quality remains prominent on end users’ (the learners’) agenda. It is no surprise that many non-motivated adult learners abandon prematurely their e-learning experiences. This is attributed in a great extent to the poor design and usability of e-learning applications. This paper proposes a usability framework that addresses the user as a learner and extends the current e-learning usability practice by focusing on the affective dimension of learning, a frequently neglected issue in e-learning developments. Motivation to learn, a dominant affective factor related with learning effectiveness, has been similarly neglected. Usability and instructional design constructs as well as Keller’s ARCS Model are being employed within the framework proposed in this work upon which new usability evaluation methods can be based. This framework integrates web usability and instructional design parameters and proposes motivation to learn as a new type of usability dimension in designing and evaluating e-learning applications.

Design and Simulation of New Type Reactor in the Wastewater Treatment System Based on Discharge Plasma

2019 ◽  
Vol 47 (1) ◽  
pp. 952-957
Author(s):  
Hong-Jun Xiang ◽  
Bin Lei ◽  
Xi-Chao Yuan ◽  
Qing-Ao Lv ◽  
Qian Zhang
Keyword(s):  
Wastewater Treatment ◽  
Discharge Plasma ◽  
Treatment System ◽  
Wastewater Treatment System ◽  
Type Reactor ◽  
New Type

Evaluation of the effects of temperature and pressure on the extraction of eugenol from clove (Syzygium aromaticum) leaves using supercritical CO2

2019 ◽  
Vol 143 ◽  
pp. 313-320 ◽  
Author(s):  
Paula Cassiana Frohlich ◽  
Kátia Andressa Santos ◽  
Fernando Palú ◽  
Lúcio Cardozo-Filho ◽  
Camila da Silva ◽  
...  
Keyword(s):  
Supercritical Co2 ◽  
Syzygium Aromaticum ◽  
Effects Of Temperature ◽  
Temperature And Pressure

Usability in the Context of e-Learning

2009 ◽  
Vol 5 (4) ◽  
pp. 37-59 ◽  
Author(s):  
Panagiotis Zaharias
Keyword(s):  
Instructional Design ◽  
Adult Learners ◽  
End Users ◽  
Usability Evaluation ◽  
Design Parameters ◽  
Motivation To Learn ◽  
The Poor ◽  
E Learning ◽  
New Type ◽  
Usability Evaluation Methods

The issue of e-learning quality remains prominent on end users’ (the learners’) agenda. It is no surprise that many non-motivated adult learners abandon prematurely their e-learning experiences. This is attributed in a great extent to the poor design and usability of e-learning applications. This paper proposes a usability framework that addresses the user as a learner and extends the current e-learning usability practice by focusing on the affective dimension of learning, a frequently neglected issue in e-learning developments. Motivation to learn, a dominant affective factor related with learning effectiveness, has been similarly neglected. Usability and instructional design constructs as well as Keller’s ARCS Model are being employed within the framework proposed in this work upon which new usability evaluation methods can be based. This framework integrates web usability and instructional design parameters and proposes motivation to learn as a new type of usability dimension in designing and evaluating e-learning applications.

ANTIBAC — A NEW TYPE OF CHLORINE SANITIZER*

1952 ◽  
Vol 15 (6) ◽  
pp. 285-293 ◽  
Author(s):  
Leslie R. Bacon ◽  
Alfred L. Sotier
Keyword(s):  
Preliminary Data ◽  
Storage Stability ◽  
Active Agent ◽  
Great Promise ◽  
Organic Loading ◽  
Ph Adjustment ◽  
Adverse Conditions ◽  
New Type ◽  
Effects Of Temperature

The germicidal performance of Anti-bac, a newly developed preparation based on the active agent 1,3-dichloro-5, 5-dimethylhydantoin, has been tested by several methods. The activity is of the same order as shown by hypochlorite preparations, and is superior under the adverse conditions of organic loading. Preliminary data are given for the effects of temperature and pH adjustment on performance, and on storage stability and action on metals. Antibac shows great promise for general disinfection and sanitation service, and in view of its combination of high germicidal activity and excellent resistance to depreciation may be used to advantage in fields hitherto dominated by hypochlorites.

Development of a Ceramic Pressurized Volumetric Solar Receiver for Supercritical CO2 Brayton Cycle

2014 ◽  
Author(s):  
S. D. Khivsara ◽  
Rathindra Nath Das ◽  
T. L. Thyagaraj ◽  
Shriya Dhar ◽  
V. Srinivasan ◽  
...  
Keyword(s):  
Thermal Efficiency ◽  
Supercritical Co2 ◽  
Material Selection ◽  
Radiation Heat Transfer ◽  
Small Scale ◽  
Attractive Alternative ◽  
Transfer Model ◽  
Outlet Temperature ◽  
Brayton Cycle ◽  
Solar Thermal Energy

Recently, the supercritical CO2 (s-CO2) Brayton cycle has been identified as a promising candidate for solar-thermal energy conversion due to its potentially high thermal efficiency (50%, for turbine inlet temperatures of ∼ 1000K). Realization of such a system requires development of solar receivers which can raise the temperature of s-CO2 by over 200K, to a receiver outlet temperature of 1000K. Volumetric receivers are an attractive alternative to tubular receivers due to their geometry, functionality and reduced thermal losses. A concept of a ceramic pressurized volumetric receiver for s-CO2 has been developed in this work. Computational Fluid Dynamics (CFD) analysis along with a Discrete Ordinate Method (DOM) radiation heat transfer model has been carried out, and the results for temperature distribution in the receiver and the resulting thermal efficiency are presented. We address issues regarding material selection for the absorber structure, window, coating, receiver body and insulation. A modular small scale prototype with 0.5 kWth solar heat input has been designed. The design of a s-CO2 loop for testing this receiver module is also presented in this work.

scholarly journals On the Conceptual Design of Novel Supercritical CO2 Power Cycles for Waste Heat Recovery

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 370 ◽  
Author(s):  
Giovanni Manente ◽  
Mário Costa
Keyword(s):  
High Temperature ◽  
Heat Source ◽  
Thermal Efficiency ◽  
Supercritical Co2 ◽  
Heat Recovery ◽  
Waste Heat ◽  
Heat Extraction ◽  
Heat Sources ◽  
Partial Heating ◽  
Single Flow

The supercritical CO2 power cycle (s-CO2) is receiving much interest in the utilization of waste heat sources in the medium-to-high temperature range. The low compression work and highly regenerative layout result in high thermal efficiencies, even at moderate turbine inlet temperatures. The capability of heat extraction from the waste heat source is, however, limited because the heat input takes place over a limited temperature range close to the maximum cycle temperature. Accordingly, novel s-CO2 layouts have been recently proposed, aimed at increasing the heat extraction from the heat source while preserving as much as possible the inherently high thermal efficiency. Among these, the most promising ones feature dual expansion, dual recuperation, and partial heating. This work concentrates on the conceptual design of these novel s-CO2 layouts using a systematic approach based on the superimposition of elementary thermodynamic cycles. The overall structure of the single flow split with dual expansion (also called cascade), partial heating, and dual recuperated cycles is decomposed into elementary Brayton cycles to identify the building blocks for the achievement of a high performance in the utilization of waste heat sources. A thermodynamic optimization is set up to compare the performance of the three novel layouts for utilization of high temperature waste heat at 600 °C. The results show that the single flow split with a dual expansion cycle provides 3% and 15% more power compared to the partial heating and dual recuperated cycles, respectively, and 40% more power compared to the traditional single recuperated cycle used as the baseline. The separate evaluation of thermal efficiency and heat recovery effectiveness shows the main reasons behind the achievement of the highest performance, which are peculiar to each novel layout.

A Comparison Between ORC and Supercritical CO2 Bottoming Cycles for Energy Recovery From Industrial Gas Turbines Exhaust Gas

2021 ◽  
Author(s):  
Maria Alessandra Ancona ◽  
Michele Bianchi ◽  
Lisa Branchini ◽  
Andrea De Pascale ◽  
Francesco Melino ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Supercritical Co2 ◽  
Energy Demand ◽  
Industrial Process ◽  
Medium Size ◽  
Value Range ◽  
Industrial Gas Turbines ◽  
Process Energy

Abstract The huge amount of discharged heat from industrial gas turbines could be profitably recovered in bottoming cycles, producing electric power to help satisfying the industrial process energy demand. The present work aims at systematically evaluating thermodynamic performance of ORC and supercritical CO2 energy systems as bottomer cycles of different small/medium size industrial gas turbine models, with different power rating. The Thermoflex software, providing the GT PRO gas turbine library, has been used to model the machines performance. ORC and CO2 systems specifics have been chosen in line with industrial products, experience and technological limits. In the case of pure electric production, the results highlight that the ORC configuration shows the highest plant net electric efficiency. The average increment in the overall net electric efficiency is promising for both the configurations (7 and 11 percentage points, respectively if considering supercritical CO2 or ORC as bottoming solution). Concerning the cogenerative performance, the CO2 system exhibits at the same time higher electric efficiency and thermal efficiency, if compared to ORC system, being equal the installed topper gas turbine model. The ORC scarce performance is due to the high condensing pressure, imposed by the temperature required by the thermal user. CO2 configuration presents instead very good cogenerative performance with thermal efficiency comprehended between 35 % and 46 % and the PES value range between 10 % and 22 %. Finally, analyzing the relationship between capital cost and components size, it is estimated that the ORC configuration could introduce an economical saving with respect to the CO2 configuration.

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