The Experts below are selected from a list of 14178 Experts worldwide ranked by ideXlab platform
A M Bassily - One of the best experts on this subject based on the ideXlab platform.
-
modeling numerical optimization and irreversibility reduction of a triple pressure reheat combined cycle
Energy, 2007Co-Authors: A M BassilyAbstract:The main methods for improving the efficiency of the combined cycle are: increasing the inlet Temperature of the gas turbine (TIT), reducing the irreversibility of the heat recovery steam generator (HRSG), and optimization. In this paper, modeling and optimization of the triple-pressure reheat combined cycle as well as irreversibility reduction of its HRSG are considered. Constraints were set on the Minimum Temperature Difference for pinch points (PPm), the Temperature Difference for superheat approach, the steam turbine inlet Temperature and pressure, the stack Temperature, and the dryness fraction at steam turbine outlet. The triple-pressure reheat combined cycle was optimized at 41 different maximum values of TIT using two different methods; the direct search and the variable metric. A feasible technique to reduce the irreversibility of the HRSG of the combined cycle was introduced. The optimized and the reduced-irreversibility triple-pressure reheat combined cycles were compared with the regularly designed triple-pressure reheat combined cycle, which is the typical design for a commercial combined cycle. The effects of varying the TIT on the performance of all cycles were presented and discussed. The results indicate that the optimized triple-pressure reheat combined cycle is up to 1.7% higher in efficiency than the reduced-irreversibility triple-pressure reheat combined cycle, which is 1.9–2.1% higher in efficiency than the regularly designed triple-pressure reheat combined cycle when all cycles are compared at the same values of TIT and PPm. The optimized and reduced-irreversibility combined cycles were compared with the most efficient commercially available combined cycle at the same value of TIT.
-
modeling numerical optimization and irreversibility reduction of a dual pressure reheat combined cycle
Applied Energy, 2005Co-Authors: A M BassilyAbstract:Abstract Optimizing the gas-turbine combined-cycle is an important method for improving its efficiency. In this paper, a dual-pressure reheat combined-cycle was modeled and optimized for 80 cases. Constraints were set on the Minimum Temperature-Difference for pinch points (PPm), superheat approach Temperature-Difference, steam-turbine inlet Temperature and pressure, stack Temperature, and dryness fraction at the steam-turbine’s outlet. The dual-pressure reheat combined-cycle was optimized using two different methods; the direct search and the variable metric. A technique to reduce the irreversibility of the steam generator of the combined cycle was introduced. The optimized and the reduced-irreversibility dual-pressure reheat combined-cycles were compared with the regularly-designed dual-pressure reheat combined-cycle, which is the typical design for a commercial combined-cycle. The effects of varying the inlet Temperature of the gas turbine (TIT) and PPm on the performance of all cycles were presented and discussed. The results indicated that the optimized combined-cycle is up to 1% higher in efficiency than the reduced-irreversibility combined-cycle, which is 2–2.5% higher in efficiency than the regularly-designed combined-cycle when compared for the same values of TIT and PPm. The advantages of the optimized and reduced-irreversibility combined-cycles were manifested when compared with the most efficient commercially-available combined cycle at the same value of TIT.
Zainuddin Abdul Manan - One of the best experts on this subject based on the ideXlab platform.
-
Selection of Minimum Temperature Difference (ΔTmin) for heat exchanger network synthesis based on trade-off plot
Applied Energy, 2016Co-Authors: Suraya Hanim Abu Bakar, Mohd. Kamaruddin Abd. Hamid, Sharifah Rafidah Wan Alwi, Zainuddin Abdul MananAbstract:Abstract This paper presents a systematic technique to select the optimal design target for the heat exchanger network (HEN) synthesis by using a new trade-off plot which considers aspects of design, controllability in terms of steady state flexibility and sensitivity analysis, and cost. By selecting the HEN design target according to this guideline, the designer is able to predict the design, operability, and controllability of the designed HEN at the beginning of the synthesis stage. In this study, the HEN design target that needs to be optimized is the value of the Minimum Temperature Difference ( Δ T min ). In traditional HEN synthesis, designers only consider the trade-off between capital and operating costs in selecting the best Δ T min . As a result, the HEN design at the selected Δ T min may not be optimum in terms of steady state controllability. In addition to considering the capital and operating costs, the proposed new method provides additional design insights in terms of energy recovery, operability, controllability (steady state) through the flexibility and sensitivity. The proposed trade-off plot allows designers to choose the most suitable design target either for the purpose of improving a network’s energy recovery and/or controllability. A case study has been applied to test the capability of the new proposed trade-off plot. The results show that Δ T min = 40 °C is the optimal design target to synthesize flexible and operable HEN.
Atsushi Tsutsumi - One of the best experts on this subject based on the ideXlab platform.
-
A cryogenic air separation process based on self-heat recuperation for oxy-combustion plants
Applied Energy, 2016Co-Authors: Yasuki Kansha, Masanori Ishizuka, Yuping Liu, Chunfeng Song, Atsushi TsutsumiAbstract:Abstract An advanced cryogenic air separation process for oxy-combustion is proposed, based on self-heat recuperation technology. In contrast to double columns in the conventional cryogenic air separation process, a single distillation column only is used in the proposed process. By using self-heat recuperation technology, the heat of N2 product gas from the top of the single distillation column is recirculated by exchanging heat with the liquid O2 in the bottom and feed streams, largely reducing the energy requirement. The simulation results showed that the energy requirement of the proposed cryogenic air separation process was reduced by 20.2% compared with the conventional process when producing O2 with low purity (95 mol%). The influence of compressor efficiency, Minimum Temperature Difference in the main condenser and the O2 product purity on the energy requirement were also investigated.
-
Theoretical and Experimental Investigation on the Energy Consumption of Self-heat Recuperation Using Magnetocaloric Effect
Chemical engineering transactions, 2014Co-Authors: Cal E, Yui Kotani, Yasuki Kansha, Masanori Ishizuka, Atsushi TsutsumiAbstract:The Minimum energy consumption needed for heat circulation is derived from the exergy destruction due to heat exchange in terms of Temperature-entropy diagram. The obtained value is compared with the numerical energy consumption when magnetocaloric effect is applied to self-heat recuperation technology. Furthermore, a magnetocaloric heat circulator has newly been constructed and its energy consumption has been measured. It is explained by the Temperature-entropy diagram, that the Minimum energy consumption needed for heat circulation is proportional to the Minimum Temperature Difference needed for heat exchange. In a magnetocaloric heat circulator, the heat transfer between the process fluid and the working material is direct, thus leading to small Temperature Difference during heat exchange and small input work required for heat circulation.
-
Application of the self-heat recuperation technology for energy saving in biomass drying system
Fuel Processing Technology, 2014Co-Authors: Yuping Liu, Yasuki Kansha, Muhammad Aziz, Sankar Bhattacharya, Atsushi TsutsumiAbstract:Abstract An advanced energy-saving drying process based on self-heat recuperation technology was proposed for biomass drying. Compared with previously developed design, the newly developed design further reduced energy consumption by 40%. Energy consumptions in the drying systems were qualified and compared through the process simulator PRO/II. Energy consumption of self-heat recuperative dryers in this study can be reduced to 1/4–1/7 of that of a conventional heat recovery dryer. Effects of the heat exchange type, ratio of air to product, Minimum Temperature Difference between the hot and cold streams in the heat exchanger, and drying medium on the system energy consumption were evaluated when applying self-heat recuperation technology to a biomass drying system.
-
Self-heat Recuperative Heat Circulator with Thermoelectric Device☆
Energy Procedia, 2014Co-Authors: Renaldo N. Rasfuldi, Yui Kotani, Yasuki Kansha, Masanori Ishizuka, Atsushi TsutsumiAbstract:Abstract Self-heat recuperation (SHR) technology has been proven to reduce exergy loss in different process systems, which lead to large energy savings due to its non-combustion process. The purpose of this research is to develop a novel self-heat recuperative heat circulation system using thermoelectric (TE) device as a heat circulator for non-gaseous systems. Most research involving TE coolers is related to maximizing the Temperature Difference (ΔT) of a device, whereas in self-heat recuperative heat circulator, a large ΔT is not required, but only a Minimum Temperature Difference between the surfaces of the TE device and process fluid (ΔT min ) for self-heat exchange is required in order to use it as a heat circulator. The lower ΔT can improve COP of TE devices significantly.
Jiří Jaromír Klemeš - One of the best experts on this subject based on the ideXlab platform.
-
Evaluation of the energy saving opportunities for palm oil refining process: Sahabat Oil Products (SOP) in Lahad Datu, Malaysia
Clean Technologies and Environmental Policy, 2016Co-Authors: Seri Rahimah Lidu, Nurul‘ain Mohamed, Jiří Jaromír Klemeš, Petar Sabev Varbanov, Suzana YusupAbstract:Palm Oil industry is one of the major contributors to Malaysia’s economic activity. Accounting for 39 % of the world palm oil production and 44 % of world exports, Malaysia holds an important niche in fulfiling the growing global needs for oils and fats sustainably. This industry has high potential for further improvements especially in terms of energy saving as a major contributor to cost and emission reduction. An analysis of the refining process of palm oil in Sahabat Oil Products, Lahad Datu has been performed and presented in this paper for scoping potential energy and cost savings using heat integration. A first stage optimisation of the Minimum Temperature Difference, ∆ T _min, of a heat exchanger network (HEN) has been performed. The goal has been to evaluate the maximal possible heat recovery as well as the appropriate placement of utilities. The HEN design is presented in both grid diagram and shifted retrofit thermodynamic grid diagram (SRTGD). SRTGD representation has been illustrated in this paper as a useful tool for guiding eventual future retrofit. The capital-energy trade-off of the heat recovery targets indicates optimum ∆ T _min of 12.3 °C. The hot and cold utility targets at ∆ T _min = 12.3 °C are 1419 and 1649 kW, indicating potential saving of 3.5 and 3.1 % as compared to the existing utility consumption and emissions. Future work could proceed further to seek potentially viable retrofit of the existing heat recovery network.
-
Total Site Targeting with Stream Specific Minimum Temperature Difference
Chemical engineering transactions, 2012Co-Authors: Zsófia Fodor, Jiří Jaromír Klemeš, Petar Sabev Varbanov, Michael R.w. Walmsley, Martin John Atkins, Timothy Gordon WalmsleyAbstract:The paper focuses on extending traditional Total Site Integration methodology to produce more meaningful utility and heat recovery targets for the process design. The traditional methodology leads to inadequate results due to inaccurate estimation of the overall Total Site heat recovery targets. The new methodology is a further development of a recently extended traditional pinch methodology. The previous extension was on the introduction of using an individual Minimum Temperature Difference (ΔTmin) for different processes so that the ΔTmin is more representative of the specific process. Further this paper deals with stream specific ΔTmin inside each process by setting different ΔT contribution (ΔTcont) and also using different ΔTcont between the process streams and the utility systems. The paper describes the further extended methodology called stream specific targeting methodology. A case study applying data from a real diary factory is used to show the Differences between the traditional, process specific and stream specific total site targeting methodologies. The extended methodology gives more meaningful results at the end of the targeting with this avoiding the over or under estimated heat exchanger areas in the process design.
-
Total Site targeting with process specific Minimum Temperature Difference (ΔTmin)
Energy, 2012Co-Authors: Petar Sabev Varbanov, Zsófia Fodor, Jiří Jaromír KlemešAbstract:The paper deals with an extension of Total Site Integration to Locally Integrated Energy Sectors producing more realistic utility and heat recovery targets. Process Heat Integration (based on Pinch Analysis) aims to minimise the amount of energy mostly used in industrial processes. It is still an open question how to solve the Total Site targeting problem when different values for the Minimum allowed Temperature Differences (ΔTmin) are specified for each process on the site. A single uniform ΔTmin for all processes integrated in a Total Site, as practiced to date, cannot be generally optimal. Such an assumption may be too simplifying and lead to inadequate results due to imprecise estimation of the overall Total Site heat recovery targets. The modified Total Site targeting procedure, proposed in this paper, allows obtaining more realistic heat recovery targets for Total Sites. It is illustrated with a case study for Locally Integrated Energy Sectors, also providing a comparison with the traditional targeting procedure and the advantages offered by the modified one.
Petar Sabev Varbanov - One of the best experts on this subject based on the ideXlab platform.
-
Evaluation of the energy saving opportunities for palm oil refining process: Sahabat Oil Products (SOP) in Lahad Datu, Malaysia
Clean Technologies and Environmental Policy, 2016Co-Authors: Seri Rahimah Lidu, Nurul‘ain Mohamed, Jiří Jaromír Klemeš, Petar Sabev Varbanov, Suzana YusupAbstract:Palm Oil industry is one of the major contributors to Malaysia’s economic activity. Accounting for 39 % of the world palm oil production and 44 % of world exports, Malaysia holds an important niche in fulfiling the growing global needs for oils and fats sustainably. This industry has high potential for further improvements especially in terms of energy saving as a major contributor to cost and emission reduction. An analysis of the refining process of palm oil in Sahabat Oil Products, Lahad Datu has been performed and presented in this paper for scoping potential energy and cost savings using heat integration. A first stage optimisation of the Minimum Temperature Difference, ∆ T _min, of a heat exchanger network (HEN) has been performed. The goal has been to evaluate the maximal possible heat recovery as well as the appropriate placement of utilities. The HEN design is presented in both grid diagram and shifted retrofit thermodynamic grid diagram (SRTGD). SRTGD representation has been illustrated in this paper as a useful tool for guiding eventual future retrofit. The capital-energy trade-off of the heat recovery targets indicates optimum ∆ T _min of 12.3 °C. The hot and cold utility targets at ∆ T _min = 12.3 °C are 1419 and 1649 kW, indicating potential saving of 3.5 and 3.1 % as compared to the existing utility consumption and emissions. Future work could proceed further to seek potentially viable retrofit of the existing heat recovery network.
-
Total Site Targeting with Stream Specific Minimum Temperature Difference
Chemical engineering transactions, 2012Co-Authors: Zsófia Fodor, Jiří Jaromír Klemeš, Petar Sabev Varbanov, Michael R.w. Walmsley, Martin John Atkins, Timothy Gordon WalmsleyAbstract:The paper focuses on extending traditional Total Site Integration methodology to produce more meaningful utility and heat recovery targets for the process design. The traditional methodology leads to inadequate results due to inaccurate estimation of the overall Total Site heat recovery targets. The new methodology is a further development of a recently extended traditional pinch methodology. The previous extension was on the introduction of using an individual Minimum Temperature Difference (ΔTmin) for different processes so that the ΔTmin is more representative of the specific process. Further this paper deals with stream specific ΔTmin inside each process by setting different ΔT contribution (ΔTcont) and also using different ΔTcont between the process streams and the utility systems. The paper describes the further extended methodology called stream specific targeting methodology. A case study applying data from a real diary factory is used to show the Differences between the traditional, process specific and stream specific total site targeting methodologies. The extended methodology gives more meaningful results at the end of the targeting with this avoiding the over or under estimated heat exchanger areas in the process design.
-
Total Site targeting with process specific Minimum Temperature Difference (ΔTmin)
Energy, 2012Co-Authors: Petar Sabev Varbanov, Zsófia Fodor, Jiří Jaromír KlemešAbstract:The paper deals with an extension of Total Site Integration to Locally Integrated Energy Sectors producing more realistic utility and heat recovery targets. Process Heat Integration (based on Pinch Analysis) aims to minimise the amount of energy mostly used in industrial processes. It is still an open question how to solve the Total Site targeting problem when different values for the Minimum allowed Temperature Differences (ΔTmin) are specified for each process on the site. A single uniform ΔTmin for all processes integrated in a Total Site, as practiced to date, cannot be generally optimal. Such an assumption may be too simplifying and lead to inadequate results due to imprecise estimation of the overall Total Site heat recovery targets. The modified Total Site targeting procedure, proposed in this paper, allows obtaining more realistic heat recovery targets for Total Sites. It is illustrated with a case study for Locally Integrated Energy Sectors, also providing a comparison with the traditional targeting procedure and the advantages offered by the modified one.