scholarly journals Hydrothermal Energy Systems Development in the USA

Author(s):  
Radon Tolman ◽  
Ronald C. Timpe

A revolutionary hydrothermal steam generator is being developed by a federal, state university and industry partnership in the US to enhance economic growth and trade. The new generator is designed to accept solutions and slurries without corrosion and deposition on heat transfer surfaces up to the supercritical conditions of water, above 221 bar (3205 psia) and 374 C (705 F). The generator will produce steam from low quality water, such as from geothermal sources, for increased electric power generation. Water treatment costs and effluents will be eliminated for “zero discharge.” To improve efficiency and limit carbon dioxide and other emissions, the new steam generator will be tested for converting wastewater slurries of low-cost fuels and “negative value” wastes such as hazardous wastes, composted municipal wastes and sludges, to clean gas turbine fuel, hydrocarbon liquids, and activated carbon. Bench-scale results at sub- and supercritical conditions for lignite, refuse derived fuel, tire rubber and activated carbon are presented. An advanced continuous-flow pilot plant is being designed to test the generator over a wide range of operating conditions, including slurry feed up to 30 percent solids. Demonstration of the hydrothermal steam generator will be followed by design and construction of combined-cycle energy systems.

2020 ◽  
Vol 32 (5) ◽  
pp. 1121-1127
Author(s):  
Mahesh Kumar Gupta ◽  
P.K. Tandon ◽  
Neelam Shukla ◽  
Harendra Singh ◽  
Shalini Srivastava

Acid activated carbon obtained from cheap, non-toxic and locally available banana peel was used as a low cost and efficient adsorbent for the removal of dyes methyl orange and rhodamine-B from the aqueous solution. Changes in the resulting material before and after activation and after treatment were studied by different techniques, such as SEM-EDX, XRD, FTIR measurements. Effects of duration of treatment, amount of banana peel activated carbon, pH, and initial methyl orange and rhodamine-B concentration, on the removal of dye were studied to get optimum conditions for maximum dye removal. Removal efficiency of the activated ash remains almost constant in a wide range of pH from 2.5 to 5.6. In 75 min at room temperature removal of 98.5 % methyl orange (anionic) and 99.0 % rhodamine-B (cationic) dyes with 0.1 g and 0.125 g, respectively was obtained from the contaminated water having 10 ppm dye concentration.


Author(s):  
Vittorio Verda ◽  
Luis Serra ◽  
Antonio Valero

This paper presents a summary of our most recent advances in Thermoeconomic Diagnosis, developed during the last three years [1–3], and how they can be integrated in a zooming strategy oriented towards the operational diagnosis of complex systems. In fact, this paper can be considered a continuation of the work presented at the International Conference ECOS’99 [4–6] in which the concepts of malfunction (intrinsic and induced) and dysfunction [7] were analyzed in detail. These concepts greatly facilitate and simplify the analysis, the understanding and the quantification of how the presence of an anomaly, or malfunction, affects the behavior of the other plant devices and of the whole system. However, what remains unresolved is the so-called inverse problem of diagnosing [3], i.e. given two states of the plant (actual and reference operating conditions), find the causes of deviation of the actual conditions with respect to the reference conditions. The present paper tackles this problem and describes significant advances in addressing how to locate the actual causes of malfunctions, based on the application of procedures for filtering induced effects that hide the real causes of degradation. In this paper a progressive zooming thermoeconomic diagnosis procedure, which allows one to concentrate the analysis in an ever more specific zone is described and applied to a combined cycle. In an accompanying paper (part 2 [8]) the accuracy of the diagnosis results is discussed, depending on choice of the thermoeconomic model.


Author(s):  
Emad Hamid ◽  
Mike Newby ◽  
Pericles Pilidis

The high thermal efficiency and the use of low carbon content fuel (e.g., natural gas) have made the Combined Cycle Power Plant (CCPP) one of the best choices for power generation due to its benefits associate with low cost and low environmental impact. The performance of Unfired Steam Cycle (USC) as a part of the CCPP has significant impact on the performance of the whole power plant as it provides the CCPP with around one third of the total useful power. An accurate performance simulation of the USC is therefore necessary to analyze the effects of various operating parameters on the performance of combined cycle power plant. In this paper, a performance simulation approach for an unfired steam cycle using single and dual pressure-level of an OTSG is presented. The developed modeling method has been applied to the performance simulation of an existing unfired steam cycle power generation unit installed at Manx Electricity Authority and the results are promising. A comparison between simulated and actual performance at design and off design operating conditions of the same USC has shown a remarkable agreement with errors values below 1%.


2015 ◽  
Vol 5 (4) ◽  
pp. 610-618 ◽  
Author(s):  
Qian Liu ◽  
Lujie Zhang ◽  
Pan Hu ◽  
Ruihua Huang

In this work, activated carbon (AC) coated by chitosan was synthesized and characterized by Fourier transform infrared spectrophotometer and scanning electron microscope (SEM) techniques. The removal of aniline from aqueous solutions by AC coated by chitosan was investigated. The factors affecting the adsorption of aniline onto AC coated by chitosan, including the ratio of AC to chitosan, adsorbent dosage, pH value of solution, initial aniline concentration, and contact time were evaluated. These results showed that the optimum operating conditions were: the ratio of AC to chitosan = 0.5, adsorbent dosage = 0.2 g, and the adsorption of aniline from aqueous solutions had better removal in the concentration range of 20–50 mg/L. This adsorbent allowed high removal toward aniline in a wide range of pH. The equilibrium time was 100 minutes. The Freundlich model exhibited better correlation of the equilibrium adsorption data. The pseudo-second-order kinetic equation could better describe the kinetic behavior of aniline adsorption.


Author(s):  
David R. Logeais

A gas turbine in the size range of 20,000 hp (14.9 MW) was retrofitted with a heat recovery steam generator (HRSG). The HRSG produces high pressure superheated steam for use in a steam turbine. Supplementary firing is used to more than double the steam production over the unfired case. Because of many unusual constraints, an innovative design of the HRSG was formulated. These design constraints included: 1. A wide range of operating conditions was to be accommodated. 2. Very limited space in the existing plant. 3. A desire to limit the field construction work necessary in order to provide a short turn-around time. This paper will discuss the design used to satisfy these conditions.


TAPPI Journal ◽  
2011 ◽  
Vol 10 (7) ◽  
pp. 37-42 ◽  
Author(s):  
PETER W. HART

As the cost of energy and processing chemicals changes, the optimal, lowest cost operating conditions within a pulp mill also change. Additionally, the optimal cost operating point within one area of the mill may not result in a total mill low cost operation. Three practical pulp mill examples have been analyzed under varying cost constraints for energy and chemicals to determine the impact of energy and chemical cost changes on the low cost operating point. These examples include changing the digester kappa number target, changing the brownstock washing dilution factor, and the conversion of a continuous digester from one type of cooking process to a lower energy cooking process. Selected mill operating results and laboratory data were employed to tune various process simulation models to obtain cost predictions over a wide range of operating conditions.


Author(s):  
Chinbay Fan ◽  
Michael Onischak ◽  
William Liss

Currently, fuel cell cost reduction and long life are major priorities for fuel cells to be commercially successful for vehicle, stationary, or portable power applications. In the last five years, Gas Technology Institute (GTI) has formulated and developed a low cost, long lifetime, high conductivity proton exchange membrane (PEM) yielding state-of-the-art fuel cell performance. Additionally, a non-coated, corrosion-resistant metal alloy bipolar separator plate has been patented and tested for both hydrogen-fueled and direct methanol fueled PEMFC applications. Tests in fuel cells plus out-of-cell ASTM corrosion tests have shown very low corrosion rates under fuel cell operating conditions. Metal alloy separator plates have run for over 23,000 hours in cells with corrosion rates an order of magnitude less than the DOE target of 1 μA/cm2. GTI’s fuel cell polymer membrane research focused on three criteria: (1) use of low cost materials; (2) polymer structures stable under fuel cell operating conditions; and (3) performance equal or better than current Nafion membrane electrode assemblies (MEAs). Fluorine-containing polymers were eliminated due to cost issues, environmental factors, and the negative influence fluorine ion loss has on metallic separator plates. The polymer membrane material was synthesized and cast into films, then fabricated into MEAs. The cost of the membrane (raw materials plus film processing materials) is estimated to be less than $10/m2 — or less than 10% of available technology. A variety of out-of-cell testing showed the membrane has sufficient strength, flexibility, and conductivity to serve as an ion conducting membrane for fuel cells. A series of 60 cm2 active area single cells and short stacks were operated over a wide range of fuel cell conditions, showing state-of-the-art MEA performance with long-term polymer stability.


Author(s):  
Jeffrey N. Phillips ◽  
Meherwan P. Boyce ◽  
Jay Grandmont ◽  
Leonard Angello

A spreadsheet-based performance monitoring software program has been developed which uses OEM correction curves and thermodynamic analysis to compare actual simple cycle gas turbine performance to expected performance over the full-range of operation including part-load. The program has been designed to require a minimum of user set-up and can interface with widely-used, third-party data historians to access plant operating data in real-time. In addition to providing overall plant performance indicators, the program also provides component-level indicators such as combustion turbine compressor section efficiency. An overview of the algorithms used to calculate actual and expected performance is provided. The advantages and shortcomings of this approach are compared to those used by others. Results are presented from initial testing of the software on a 500 MW combined cycle power featuring two GE 7FA combustion turbines. Performance results include data on the compressor section efficiency of a 7FA over a wide range of operating conditions.


Author(s):  
Ondrej Novak ◽  
Marek Bobcik ◽  
Martin Luxa ◽  
Jaroslav Fort ◽  
Bartolomej Rudas ◽  
...  

Recent trends in the electric energy market such as biomass, waste incineration or combined cycle power plants require innovative solutions in steam turbine design. Variable operating conditions cause significant changes in flow field surrounding the steam turbine last stage blades. Therefore, the enlargement of operating range for last stage blades presents new challenges in design of turbine cascades. Several turbine cascades were designed and analyzed by commercial and in-house software of CTU Prague. Selected profiles were experimentally validated in the high-speed wind tunnel for 2D cascade measurements of the Institute of Thermomechanics of the Czech Academy of Sciences which is equipped by an adjustable supersonic inlet nozzle, perforated inserts at side walls and adjustable perforated tailboard. Comparisons are presented of numerical results with optical and pneumatic measurements for a wide range of inlet and outlet Mach numbers for optimized hub and tip profile cascades.


2011 ◽  
Vol 1353 ◽  
Author(s):  
Yong Dong Jiang ◽  
Ganesh Venugopal ◽  
Marvis White ◽  
Kwang Choi ◽  
Andrew T. Hunt

ABSTRACTnGimat has commercialized a number of nanotechnology applications with all being based on its core competence of fabricating low cost high quality nanomaterials. The company offers a wide range of compositions as coatings and also in both nanopowder and dispersion forms. A few of these nanomaterials and applications will be covered as examples including superhydrophobic coatings, various nanopowders (including Li-battery based), high temperature thin wire coatings, and tunable RF components.The combustion chemical vapor deposition (CCVD) technique, which is the thin film NanoSpraySM combustion process, can be easily scaled up to large substrates and integrated into an existing production line, thus enabling a license business model. The combustion chemical vapor condensation (CCVC) technique or NanoSpraySM CCVC (nCCVC), which is the nanopowder NanoSpraySM combustion process, is also readily scalable. The manufacture of these nanopowder based products is internationally competitive even when made in the USA.


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