Effect Of The Ambient Temperature On The Performance Of Small Size SCO2 Based Pulverized Coal Power Plants

The present work focuses on the analysis of a novel coal fired sCO2 power plant concept developed in the frame of sCO2-Flex H2020 EU funded project. Fossil fuel fired power plants are expected to improve their flexibility in the future energy scenario characterized by a large share of non-predictable and nondispatchable renewable energy sources. This upcoming context requires a new generation of coal fired power plants with a smaller size, a high flexibility and minor requirements for the installation site like no need of water consumption. Carbon dioxide in supercritical cycles is recognized to be a possible solution for this technology shift and could replace in the future common steam Rankine cycles. This paper focuses on the impact of ambient temperature variation on a small size coal fired sCO2 power plants equipped with a dry cooling heat rejection unit, with the aim of understanding the effect on plant operability and system performance. A dedicate tool is implemented for offdesign behavior assessment and different control strategies are investigated. Results show that without a proper design of the heat rejection unit a small increase of ambient temperature may drastically limit the maximum attainable power output of the plant. This penalizing effect is more pronounced in hot locations, but this issue can be limited by adopting a sufficient over-sizing of the cycle heat rejection unit (HRU) or wet-and-dry solutions

Off-design of a CO2-based mixture transcritical cycle for CSP applications: Analysis at part load and variable ambient temperature

This work focuses on the off-design analysis of a simple recuperative transcritical power cycle working with the CO2 + C6F6 mixture as working fluid. The cycle is aircooled and proposed for a state-of-the-art concentrated solar plant with solar salts as heat transfer fluid in a hot region, with a cycle minimum and maximum temperature of 51 degrees C and 550 degrees C at design conditions. The design of each cycle heat exchanger (primary, recuperator and condenser) is carried out in MATLAB with referenced models and the turbine designed in CFD, providing performance maps adopted by the cycle operating in sliding pressure. The off-design of the cycle is developed with a routine simulating the thermodynamic conditions of the cycle at variable ambient temperature and thermal inputs down to 40 % of the nominal value. The results show that the cycle can efficiently run in a wide range of part load conditions and ambient temperatures, from around 0 degrees C to over 40 degrees C, with net electric cycle efficiencies from 45 % to 36 %: according to the control philosophy proposed, the condenser fans are fixed at design speed, while the cycle operates in sliding pressure, when is possible. The results evidence the flexibility and good performances of the proposed system in various operating conditions

MULTIPLE ORGAN HARVESTING: EVOLUTION OF SURGICAL TECHNIQUE. PERSONAL EXPERIENCE

SINCE 1950, kidney, liver, heart, and lung transplantations have dramatically improved, emerging as the elective treatment modality for organ failure. Nevertheless, the indications to pancreas and bowel grafting are stili controversial. Several factors have contributed such results, namely the introduction of cyclosporine (CyA) in 1981, the use of new solutions for solid organ preservation (eg, the University of Wisconsin solution), the improvement in donor selection criteria, intensive care, as well as improvement management of transplant operation and harvesting surgical technique

PENGARUH PEMBERIAN PROBIOTIK Bacillus subtilis DAN Saccharomyces cerevisiae TERHADAP PRODUKSI AYAM LAYER UMUR 51 MINGGU

2000 ekor ayam isa brown untuk menentukan efek dari bakteri Bacillus subtilis dan Saccharomyces cerevisiae yang digunakan dalam bentuk probiotik tercampur dalam pakan untuk menghasilkan produksi pada umur 51 minggu. Evaluasi dilakukan selama 8 minggu masa peletakan di Desa mronjo, kecamatan Selopuro, Kabupaten blitar. Perlakuan dibagi menjadi dua kelompok, yaitu; P0 (jagung 50% + konsentrat 35% + bekatul 15% + premix 0,2%) dan P1 (Jagung 50% + konsentrat 35% + bekatul 15% + probiotik 0,1%) dianalisis menggunakan t test. Perlakuan diulang 20 kali dengan masing masing terdapat 50 ekor ayam. Parameter meliputi: Konsumsi Pakan (g/ekor), Feed Convertion Ratio, Berat telur (g/butir), Hen Day  Production (%),  Hen  House  Production (%),  Egg  Mass  (g/ekor),  Income  Over  Feed  Cost (Rp/day). Hasil penelitian menunjukan  bahwa berbeda nyata (P>0,05) pada Konsumsi Pakan (114,35 vs 113,78 g/ekor/hari); Feed Convertion Ratio (2,43 vs 2,51); Hen Day Production (75,91 vs 73,72%); Hen House Production (74,96 vs 72,53%); Egg Mass (48,21 vs 46,74 g/ekor/hari); Income Over Feed Cost (157,26 vs 123,50 Rp/ekor) tetapi tidak berbeda nyata pada berat telur ( 63,50 vs 63,50 g/butir). Kesimpulan  hasil   penelitian  pemberian  bakteri   Bacillus   subtilis   dan   Saccharomyces cerevisiae pada hasil produksi masih belum bisa optimal. Disarankan perlunya penelitian lebih lanjut agar dapat digunakan dalam meningkatkan produksi ayam petelur

I TRAPIANTI D'ORGANO

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