Abstract

The cement production process is energy intensive both in terms of the thermal energy (firing the kiln, drying and De carbonation) and electrical energy for driving the numerous drives within the process line. The average specific power consumption of the case study plant was 111 kWh/ton of cement with an average peak demand of 9.7 MW. The high cost of electric power at 0.14 USD/kWh results in very high cost of production that significantly lowers the companys profit margin and limits its competitive advantage. The generation of electrical power from waste heat recovery would reduce the electricity power bill through partially substituting the power procured from the national grid. This research evaluated the potential that the plant has for generating electrical power from the hot waste gases vented into the atmosphere and it was found that the plant has the potential to generate 3.4 MWh of electrical power. This results to a net potential to generate 2.89 MWh of electrical power after factoring in the auxiliary power consumption by Waste heat recovery plant system at 15%. This ultimately gave a reduction of 33% in the electricity power bill of the case study plant. The paper recommends the installation of a steam rankine cycle for the power generating plant. In this work the authors designed the steam boilers for the waste heat recovery plant for conversion of thermal energy to electrical energy, selected a commercial steam turbine and evaluated its economic feasibility and established that the designed plant would have a simple payback period of 2.7 years.

Abstract

In most gravity fed water transmission pipelines, it is desired to reduce excess pressure head to prevent undue strain on a pipeline and lower the incidence of leaks. Normally this is done with pressure reducing valves that essentially burn off this excess pressure as heat. The LucidPipe™ system converts it to low cost electricity thereby removing unwanted pressure and generating energy at the same time - energy that can be put used behind the grid or put back on the grid. The LucidPipe™ system extracts a small percentage of pressure head providing nearly invisible operation allowing water operators to fulfill their primary mission of delivering water to consumers. Because the LucidPipe™ system extracts only a small percentage of pressure head when operating, and about 1 psi of pressure head when stopped, it is virtually invisible in a pipe network and can be placed directly in-line without the need of a bypass for the turbine. Traditional hydropower turbines effectively halt the flow of water when stopped, and can cause dangerous water hammer when grid power is disconnected so they must be placed in a bypass to not interrupt the safe delivery of water. Also, traditional hydropower turbines operate in a narrow band of pressures and flows whereas the LucidPipe™ system has a wide operating range typically found in municipal water transmission system. The LucidPipe™ system adjusts to meet the demands of water delivery rather than a water operator having to adjust the water to meet the demands of the turbine.

Abstract

Implementing distributed utility can strengthen the local distribution system and help avoid or delay the expense of upgrading transformers and feeders. The gas turbine-generator set is an attractive option based on its low front-end capital cost, reliable performance at unmanned stations, and environmental performance characteristics. This report assesses gas turbine utilization issues from a perspective of fuel supply pressure requirements and discusses both cost and operational factors. A primary operational consideration for siting gas turbines on the electric distribution system is whether the local gas distribution company can supply gas at the required pressure. Currently available gas turbine engines require gas supply pressures of at least 150 pounds per square inch gauge, more typically, 250 to 350 psig. Few LDCs maintain line pressure in excess of 125 psig. One option for meeting the gas pressure requirements is to upgrade or extend an existing pipeline and connect that pipeline to a high-pressure supply source, such as an interstate transmission line. However, constructing new pipeline is expensive, and the small volume of gas required by the turbine for the application offers little incentive for the LDC to provide this service. Another way to meet gas pressure requirements is to boost the compression of the fuel gas at the gas turbine site. Fuel gas booster compressors are readily available as stand-alone units and can satisfactorily increase the supply pressure to meet the turbine engine requirement. However, the life-cycle costs of this equipment are not inconsequential, and maintenance and reliability issues for boosters in this application are questionable and require further study. These factors may make the gas turbine option a less attractive solution in DU applications than first indicated by just the $/kW capital cost. On the other hand, for some applications other DU technologies, such as photovoltaics, may be the more attractive option. Document type: Report

Abstract

Uncontained, high-energy gas turbine engine fragments are a potential threat to air-transportable containers carried aboard jet aircraft. The threat to a generic example container is evaluated by probability analyses and penetration testing to demonstrate the methodology to be used in the evaluation of a specific container/aircraft/engine combination. Fragment/container impact probability is the product of the uncontained fragment release rate and the geometric probability that a container is in the path of this fragment. The probability of a high-energy rotor burst fragment from four generic aircraft engines striking one of the containment vessels aboard a transport aircraft is approximately 1.2 {times} 10{sup {minus}9} strikes/hour. Finite element penetration analyses and tests can be performed to identify specific fragments which have the potential to penetrate a generic or specific containment vessel. The relatively low probability of engine fragment/container impacts is primarily due to the low release rate of uncontained, hazardous jet engine fragments. Document type: Report

Abstract

Deregulation and open access in the natural gas pipeline industry has changed the gas business environment towards greater reliance on local energy flow rate measurement. What was once a large, stable, and well-defined source of natural gas is now a composite from many small suppliers with greatly varying gas compositions. Unfortunately, the traditional approach to energy flow measurement [using a gas chromatograph (GC) for composition assay in conjunction with a flow meter] is only cost effective for large capacity supplies (typically greater than 1 to 30 million scfd). A less costly approach will encourage more widespread use of energy measurement technology. In turn, the US will benefit from tighter gas inventory control, more efficient pipeline and industrial plant operations, and ultimately lower costs to the consumer. An assessment of the state and direction of technology for natural gas energy flow rate measurement is presented. The alternative technologies were ranked according to their potential to dramatically reduce capital and operating and maintenance (O and M) costs, while improving reliability and accuracy. The top-ranked technologies take an unconventional inference approach to the energy measurement problem. Because of that approach, they will not satisfy the fundamental need for composition assay, but have greatmore » potential to reduce industry reliance on the GC. Technological feasibility of the inference approach was demonstrated through the successful development of data correlations that relate energy measurement properties (molecular weight, mass-based heating value, standard density, molar ideal gross heating value, standard volumetric heating value, density, and volume-based heating value) to three inferential properties: standard sound speed, carbon dioxide concentration, and nitrogen concentration (temperature and pressure are also required for the last two). The key advantage of this approach is that inexpensive on-line sensors may be used to measure the inferential variables, which can then be applied (through the data correlations) to convert existing flow meters (ultrasonic, orifice, turbine, rotary, Coriolis, diaphragm, etc.) for on-line energy measurement. The practical issues for field development were evaluated using two transducers extracted from a $100 ultrasonic domestic gas meter, and a $400 infrared sensor.« le Document type: Report

Abstract

The Large-Eddy Simulations (LES) play an important role in the study and design of gas turbine combustors. In order to bring the cost of LES down, compact high-order accurate solvers that can handle complex geometry are a promising method. However, their accuracy vs cost benefit as compared to the standard finite-volume solvers is unclear when it comes to under-resolved hybrid unstructured meshes. These meshes are required to represent the industrial combustor geometries. In this work, a high-order spectral/hp (Nektar++) solver is compared to a standard finite-volume (OpenFoam) solver for a fixed cost. Two combustor-relevant configurations are employed, port-flow and swirling flow. It is found that high-order solver provides moderate accuracy improvements in terms of the mean results and significant improvements for the unsteady results.

Abstract

In the early 20th century, rapid industrial growth around the world enabled the development of many advanced mechanical structures. Some of these structures were successfully used to improve agricultural efficiency or increase people’s comfort. Such a situation was observed in 1910 in the western part of Poland, which at the time was partitioned by Habsburg Austria, the Kingdom of Prussia, and the Russian Empire. In the city of Poznan, a Polish landlord built an advanced structure to automate his farming, using freely available wind energy. At first glance, it was a classic windmill, with a multi-blade wind turbine fixed to the top of a cylindrical masonry tower. However, some additional elements demonstrate the uniqueness of such a structure at the time. One hundred years later, the structure is located at the centre of a rapidly growing area of the city. For that reason, restoration of the tower is complex and requires the reconstruction of damaged or missing elements while observing new safety regulations. In this work, the author presents the basic assumptions necessary for the future renovation process.