Investigation of the Down-Scaling Effects on the Low Swirl Burner and its Application to Microturbines

Author(s):  
Alex Frank ◽  
Peter Therkelsen ◽  
Miguel Sierra Aznar ◽  
Vi H. Rapp ◽  
Robert K. Cheng ◽  
...  

About 75% of the electric power generated by centralized power plants feeds the energy needs from the residential and commercial sectors. These power plants waste about 67% of primary energy as heat emitting 2 billion tons of CO2 per year in the process (∼ 38% of total US CO2 generated per year) [1]. A study conducted by the United States Department of Energy indicated that developing small-scale combined heat and power systems to serve the commercial and residential sectors could have a significant impact on both energy savings and CO2 emissions. However, systems of this scale historically suffer from low efficiencies for a variety of reasons. From a combustion perspective, at these small scales, few systems can achieve the balance between low emissions and high efficiencies due in part to the increasing sensitivity of the system to hydrodynamic and heat transfer effects. Addressing the hydrodynamic impact, the effects of downscaling on the flowfield evolution were studied on the low swirl burner (LSB) to understand if it could be adapted to systems at smaller scales. Utilizing particle image velocimetry (PIV), three different swirlers were studied ranging from 12 mm to 25.4 mm representing an output range of less than 1 kW to over 23 kW. Results have shown that the small-scale burners tested exhibited similar flowfield characteristics to their larger-scale counterparts in the non-reacting cases studied. Utilizing this data, as a proof of concept, a 14 mm diameter LSB with an output of 3.33 kW was developed for use in microturbine operating on a recuperated Brayton cycle. Emissions results from this burner proved the feasibility of the system at sufficiently lean mixtures. Furthermore, integration of the newly developed LSB into a can style combustor for a microturbine application was successfully completed and comfortably meet the stringent emissions targets. While the analysis of the non-reacting cases was successful, the reacting cases were less conclusive and further investigation is required to gain an understanding of the flowfield evolution which is the subject of future work.

2021 ◽  
Author(s):  
Weizhong Feng ◽  
Li Li

Abstract Global warming concerns have pushed coal-fired power plants to develop innovative solutions which reduce CO2 emissions by increasing efficiency. While new ultra-supercritical units are built with extremely high efficiency, with Pingshan II approaching 50% LHV[1], subcritical units with much lower efficiency are a major source of installed capacity. The typical annual average net efficiency of subcritical units in China is about 37% LHV, and some are lower than 35% LHV. Since the total subcritical capacity in China is about 350GW and accounts for over one third of its total coal-fired power capacity, shutting all subcritical units down is not practical. Finding existing coal-fired plants a cost-effective solution which successfully combines advanced flexibility with high efficiency and low emissions, all while extending service lives, has challenged energy engineers worldwide. However, the (now proven) benefits a high temperature upgrade offers, compared to new construction options, made this an achievement worth pursuing. After many years of substantial incremental improvements to best-in-class technology, this first-of-its-kind subcritical high temperature retrofit successfully proves that a technically and economically feasible solution exists. It increases the main and reheat steam temperatures from 538°C (1000°F) to 600°C (1112°F), and the plant cycle and turbine internal efficiencies are greatly improved. This upgrade’s greatest efficiency gains occur at low loads, which is important as fossil plants respond to renewable energy’s increased grid contributions. These are combined with best-in-class flexibility, energy-savings, and technological advances, i.e., flue gas heat recovery technology and generalized regeneration technologies [4]. This project, the world’s first high-temperature subcritical coal-fired power plant retrofit, was initiated in April 2017 and finished in August 2019. Performance reports created by Siemens and GE record unit net efficiency at rated conditions improved from 38.6% to 43.5% LHV. The boiler’s lowest stable combustion load with operational SCR, without oil-firing support, was reduced from 55% to 19%. Substitution or upgrading of high-temperature components extended the lifetime of the unit by more than 30 years. At a third of the cost of new construction, this project set a high-water-mark for retrofitting subcritical units, and meets or supports the requisite attributes for Coal FIRST, Coal Plant of the Future, proposed by the United States Department of Energy (DOE) in 2019 [2].


Author(s):  
H. Shah ◽  
R. Latorre ◽  
G. Raspopin ◽  
J. Sparrow

The United States Department of Energy, through the Pacific Northwest National Laboratory (PNNL), provides management and technical support for the International Nuclear Safety Program (INSP) to improve the safety level of VVER-1000 nuclear power plants in Central and Eastern Europe.


2015 ◽  
Vol 1092-1093 ◽  
pp. 567-572 ◽  
Author(s):  
Yang Lu Xi Li

The international Solar Decathlon competition, or SD, is known as the "Solar Energy Olympics". It was launched and organized by the United States Department of Energy for colleges and universities around the world to participate in building with solar power technology. The competition has been successfully held five times. With the help of the world’s top research and development, teams of technical and creative background design with solar energy utilization for building energy savings, automation and other technologies, to build and run a functioning, zero carbon, sustainable solar house. Tongji University and Tianjin University recently represented China at the Solar Decathlon competition, and achieved gratifying results. This paper will take the Tongji University's "Bamboo House" and Tianjin University's "Sunflower" as examples to introduce international solar house development trends.


Author(s):  
Stephen M. Hess ◽  
Nam Dinh ◽  
John P. Gaertner ◽  
Ronaldo Szilard

The concept of safety margins has served as a fundamental principle in the design and operation of commercial nuclear power plants (NPPs). Defined as the minimum distance between a system’s “loading” and its “capacity”, plant design and operation is predicated on ensuring an adequate safety margin for safety-significant parameters (e.g., fuel cladding temperature, containment pressure, etc.) is provided over the spectrum of anticipated plant operating, transient and accident conditions. To meet the anticipated challenges associated with extending the operational lifetimes of the current fleet of operating NPPs, the United States Department of Energy (USDOE), the Idaho National Laboratory (INL) and the Electric Power Research Institute (EPRI) have developed a collaboration to conduct coordinated research to identify and address the technological challenges and opportunities that likely would affect the safe and economic operation of the existing NPP fleet over the postulated long-term time horizons. In this paper we describe a framework for developing and implementing a Risk-Informed Safety Margin Characterization (RISMC) approach to evaluate and manage changes in plant safety margins over long time horizons.


Author(s):  
Julianne M. Klara

Demand for electricity in the United States is expected to grow in the foreseeable future, requiring approximately 200 gigawatts of new generating capacity by 2010. Coal-based power plants built to supply this additional baseload capacity will be required to perform at high thermal efficiency and meet tough environmental regulations, all at competitive electric generating costs. The Department of Energy (DOE) / Pittsburgh Energy Technology Center (PETC) is managing a program called Combustion 2000 that is aimed at developing technologies that will assure the continued use of coal to meet the Nation’s power generating needs well into the 21st century. The High-Performance Power System (HIPPS) element of Combustion 2000 is based on an indirectly fired combined cycle. By using an indirectly fired gas turbine and a conventional steam cycle, HIPPS cleanly produces electricity from coal at a thermal efficiency that is about one-third higher than that of today’s conventional coal-based power plants. DOE/PETC’s HIPPS program, which is described in this paper, aims to demonstrate a commercial-scale prototype plant by 2004. An engineering analysis was performed to assess the feasibility of accelerating the demonstration of HIPPS by using only those materials available today. Results predict attractive efficiencies and competitive electric generating costs for a near-term design. The feasibility of HIPPS as a repowering option has also been examined. Preliminary projections reveal that added generating capacity and reduced emissions can be accomplished at an increased overall plant efficiency and with the potential to minimize capital expenditure.


Author(s):  
D. King ◽  
G. Rochau ◽  
D. Oscar ◽  
C. Morrow ◽  
P. Tsvetkov ◽  
...  

The United States Department of Energy, Nuclear Energy Research Initiative (NERI) Direct Energy Conversion Proof of Principle (DECPOP) project has as its goal the development of a direct energy conversion process suitable for commercial development. We define direct energy conversion as any fission process that returns usable energy without an intermediate thermal process. A prior Direct Energy Conversion (DEC) project [1] has been completed and indicates that a viable direct energy device is possible if several technological issues can be overcome. The DECPOP program is focusing on two of the issues: charged particle steering and high voltage hold-off. This paper reports on the progress of the DECPOP project. Two prototype concepts are under development: a Fission Electric Cell using magnetic insulation and a Fission Fragment Magnetic Collimator using magnetic fields to direct fission fragments to collectors. Included in this paper are a short project description, an abbreviated summary of the work completed to date, a description of ongoing and future project activities, and a discussion of the potential for future research and development.


Author(s):  
Antonio Agresta ◽  
Antonella Ingenito ◽  
Roberto Andriani ◽  
Fausto Gamma

Following the increasing interest of aero-naval industry to design and build systems that might provide fuel and energy savings, this study wants to point out the possibility to produce an increase in the power output from the prime mover propulsion systems of aircrafts. The complexity of using steam heat recovery systems, as well as the lower expected cycle efficiencies, temperature limitations, toxicity, material compatibilities, and/or costs of organic fluids in Rankine cycle power systems, precludes their consideration as a solution to power improvement for this application in turboprop engines. The power improvement system must also comply with the space constraints inherent with onboard power plants, as well as the interest to be economical with respect to the cost of the power recovery system compared to the fuel that can be saved per flight exercise. A waste heat recovery application of the CO2 supercritical cycle will culminate in the sizing of the major components.


2015 ◽  
Vol 31 (5) ◽  
pp. 387-401 ◽  
Author(s):  
Simone Angioloni ◽  
Genti Kostandini ◽  
Walid Q. Alali ◽  
Corliss A. O'Bryan

AbstractThe use of mobile processing units (MPUs) for pasture poultry is growing rapidly. This study compared the economic feasibility of MPUs to two processing alternatives, traditional stationary processing on-farm plants and off-farm processing facilities. Our study combined a survey of pasture poultry farmers in Georgia, Louisiana, and Arkansas with the published research. Our findings suggest that MPUs and traditional on-farm processing alternatives have a lower processing cost, but that they require a higher initial investment than the off-farm option. In addition, off-farm processing at the United States Department of Agriculture-inspected facility allows selling products for a higher price. We therefore expect, on average, a higher per-bird profit than with the other two options. However, the excess processing capacity of the MPU can make this option the most profitable.


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