bluuebunny/crossref_metadata_2025 huggingface dataset:
Agglomeration in an Industrial FBC Boiler
Authors: Jia L. , Anthony E. J.
Published: January 2009

An industrial FBC boiler operated by a paper products company encountered significant fouling problems that required boiler shutdown and maintenance to remove deposits. CETC investigated the fouling problems. Samples from the boiler were analyzed and the results indicated that fouling was associated with near-quantitative conversion of CaO in the deposits to CaSO4, with particle expansion and possible chemical reaction sintering. There was no evidence, with possibly the exception of deposits on the distributor tuyeres, of any significant contribution from the elements traditionally associated with ash softening, e.g., Na and K. Vanadium was not considered an issue, because earlier work showed that V quantitatively combines with CaO (or MgO if present), to form high melting point vanadates. Extended sulphation tests on both bed ash and limestone were conducted in the laboratory. The results confirmed that sulphation alone was sufficient to cause strength development in the bed solids. There was also a clear difference in the strength development between bed and fly ash. Fly ash agglomerates were much weaker than those of bed ash. The long-term sulphation tests also demonstrated that the presence of “inert” ash components helps to reduce the degree of conversion of CaO to CaSO4 and to reduce the strength of the deposits. Strength development tests showed that the current limestone used in this particular boiler formed exceptionally strong deposits after being exposed to sulphation conditions for extended periods of time at 850°C. Thus it appeared that if this limestone was replaced it might benefit boiler operation. Kaolin is used at the plant to reduce distributor tuyere fouling. Chemical analysis of the deposits suggested that kaolin may help to reduce fouling, but this may well be due to physical rather than chemical behaviour of the kaolin. This work suggests that the kaolin could be replaced by another refractory material, suitably low in Na and K, since the sulphation levels in the deposits were sufficient by themselves to lead to strength development, and so any benefit of the kaolin action as an alkali metal “getter” is probably offset by that fact. Attempts to find some significant physical parameters to differentiate the tendency of bed ashes to agglomerate were not successful in this work, although previous work has suggested that bulk density may be important, with materials having a higher bulk density showing a greater tendency to agglomerate.
Mercury Removal in the Flue Gas Scrubber of a Fluidized-Bed Sewage Sludge Incinerator
Authors: Malerius O. , Werther J. , Mineur M.
Published: January 2009

The fluidized bed sewage sludge incineration plant of the city of Hamburg started its operation in May, 1997. An acid scrubber was designed as the main sink of mercury. A first modification of the mercury removal concept was presented on the 16th Fluidized Bed Combustion Conference in 2001 [1]. Mercury compounds are now dissolved in the acid scrubber and precipitated with a solution of sodium dimethyldithiocarbamate. In the year 2002 the operation of the acid scrubber has been investigated to optimize the scrubber performance. Suspension pH, amount of precipitant and density of the scrubber suspension were varied to find the optimum operation parameters for the capture of mercury at minimum cost. It was found that with an increase of the density of the scrubber suspension the mercury removal efficiency was enhanced such that the dosage of the precipitant could be decreased significantly. After this optimization process the pollutant streams into the environment were minimized. The paper presents the influence of the scrubber operation parameters on the mercury capture using continuous mercury measurements in the flue gas upstream and downstream of the scrubber. The results of this investigation led to both a minimization of the pollutant streams into the atmosphere and a reduction of the operation cost.
Case Studies: Problems Solving in Fluidized Bed Waste Fuel Incineration
Authors: Yan Rong , Liang David Tee , Tsen Leslie , Yao Kaiwen , Tay Joo Hwa
Published: January 2009

Fluidized bed combustion technology has been widely used as the new, flexible, multi-fuel boiler for waste combustion and energy recovery from low-grade fuels. However, problems such as low thermal efficiency, high emissions and bed agglomeration etc., are still encountered in operation of fluidized beds. Valuable experiences were gained from the two case studies recently conducted regarding wastes combustion in industrial-scale fluidized beds. In the first case, the performance of a fluidized bed combustor for energy recovery from oil sludge was evaluated during the commercial trials. Apart from the sludge characterization and bed material analysis, the combustion efficiency, solid flow balance, on-stack emission of CO, SOx, NOx were addressed, as well as the fluidization quality. Although the system was operated with good combustion efficiency (>99.9%), sulfur dioxide emission (>1,000ppm) was found to be substantially higher than the allowable discharge limit. It was recommended to increase limestone feed rate in order to meet the SO2 emission standard and subsequently, installation of a cyclone is suggested to remove the potential significant increase in ash and fine particles. The second case study focused on the bed agglomeration observed in a fluidized bed incinerator where burning blend of three wastes (i.e., carbon soot, biosludge and fuel oil) are involved. To understand the mechanisms and chemistry related, several analytical approaches are employed to identify the bed materials (fresh sand and degrader sand) and clinkers formed from full-scale incinerator tests. The formation of clinker is believed to follow the mechanism of partial melting and/or reactive liquid sintering. The effects of temperature and blending ratio are tested in a muffle furnace. Carbon soot is believed to be more susceptible than the other two fuels. Thermodynamic multi-Phase multi-Component Equilibrium (TPCE) calculations predict that the main low melting point species are predominant under oxidizing condition, suggesting that reducing conditions might be favorable to restrain the bed agglomeration. This study provides valuable information for the better understanding of the chemistry related to clinker formation; it also helps in developing methods for the control and possible elimination of the bed agglomeration problem for the design fuels.
Manufacturing and Construction, Operation of Karita PFBC 360 MW Unit
Authors: Koike Junichi , Nakamura Shinobu , Watanabe Hajime , Imaizumi Tsuyoshi
Published: January 2009

Pressurized Fluidized Bed Combustion Combined Cycle Power Generation, namely, PFBC is the clean coal technology, utilizing gas turbine and steam turbine, which is high efficient and friendly to earth. In early 90’s, 70 MW class PFBCs had started demonstration and commercial operation all over the world. Kyushu Electric Power Company (KyEPCO) decided to apply this technology as the real commercial unit, the world largest capacity 360MW, and put into commercial operation in July 2001. To apply PFBC to the large-scale commercial plant, it is essential to demonstrate the higher efficiency than any other conventional coal firing units. In order to achieve this, the gas turbine with higher operation pressure and advanced supercritical steam condition for steam turbine were applied. The reduction by size and weight of the equipment is the vital must to realize large scale PFBC, as 360MW unit. To reduce the pressure vessel size, the unique design of hexagon furnace was applied to install it efficiently in smaller vessel. The plant has started commercial operation in July 2001 and has well demonstrated PFBC’s technology advantages as planned. It achieved the efficiency, 41.8% as net value based on HHV, which is the highest level among existing coal fired power plants. It also verifies smooth operation, 3%L/min of Load following capability, 3 hours of hot start-up, that is comparable to conventional pulverized coal fired unit.
Operation Performance Study of 1MW Biomass Gasification Electric Energy Generation System
Authors: Wu Zhengshun , Wu Chuangzhi , Huang Haitao , Zheng Shunpeng , Dai Xianwen
Published: January 2009

This paper introduces the testing results and operation performance analysis of 1MW biomass gasification electric energy generation developed by Guangzhou Institute Of Energy Conversion. The results indicate that operation temperature of gasifier and ratios of air to fuel have a strong impact on gasification efficiency, conversion efficiency of carbon, gas productivity, gas composition and its LHV. The optimal operation parameters: temperature 780°C for wood power and 800°C for leftover fuel, 10:9 Nm3/kg ratio of air to fuel, 68% gasification efficiency, 80% conversion efficiency of carbon and LHV 6.2MJ/m3, were achieved by the testing. During the experiment, we find that fly ash carried by fuel gas and tar produced during biomass gasification are the main factors which affect continuous operation of electric generation system; the loss of sensible heat and carbon of fly ash lead to the low efficiency of electric generation system. In the meantime, the pollution emission and effect of catalyst on tar cracking are investigated. The results provide guidance for enlargement design and amelioration of electric energy generation system by biomass gasification.
Effect of Fuel Type on Formation of Agglomerates in a Large Scale Pressurized Fluidized Bed Combustor
Authors: Kobyłecki Rafał , Nowak Wojciech , Matsuo Takeshi , Imaizumi Yukio , Maruyama Mutsumi , Omata Koji , Horio Masayuki
Published: January 2009

The paper investigates agglomerate formation in the world biggest pressurized fluidized bed combustor at Karita Power Station, Japan. It was found that significant amount of agglomerates was formed at an increased boiler load bringing about a significant decrease of bed density. The agglomerates had a glassy-like molten surface and consisted of a mixture of ash from char fines and limestone particles. The main components found in the agglomerate cross-section were Ca, Al and Si oxides, all quite uniformly distributed. Agglomerate formation occurred particularly when the unit was fired with a porous Blair Athol coal that was found to produce a porous char. Firing the boiler with other coal (Nanton) that produced less porous char prevented the formation of agglomerates and enabled to maintain stable operation of the combustor. A model was developed to calculate the horizontal distribution of char surface temperature in the PFBC based on a quasi-steady heat balance for a burning char by taking into consideration the distribution of volatiles above fuel feeding nozzles, as well as char porosity. In order to take into consideration the effect of porosity on combustion of a porous char a completely new expression to estimate the reaction rate was proposed. The calculation results indicated that the agglomerates were mainly formed due to the combustion of highly porous Blair Athol chars in the poorly fluidized areas in the bed, where air-to-fuel ratio became larger. The combustion rate of less porous Nanton char was much slower then that of the Blair Athol. Accordingly, combustion temperature of its char was lower bringing about no formation of agglomerates.
Research and Development of Π-Shaped CFB Boiler With Down-Exhaust Cyclone Separator
Authors: Chen Han-Ping , Zhang Shi-Hong , Wu Zheng-Shun , Liu De-Chang , Zheng Chu-Guang , Wu Jun , Yu Yongjiang , Ren Lujun , Zhang Hua , Li Changlin , Lai Yuhua
Published: January 2009

In recent years, the circulating fluidized bed (CFB) boiler has been rapidly developed. Various CFB technology styles and boiler types have been formed. There are 3 main kinds of CFB technologies developed by universities and institutes in China. One of them is Π-shaped CFB boiler with down-exhaust cyclone separator designed by the National Laboratory of Coal Combustion (NLCC) in Huazhong University of Science and Technology (HUST). This paper summarizes the technology improvement and progress of this kind of boiler, and discusses the design considerations. This paper also describes some issues in shakedown and operation process of a 75t/h Π-shaped CFB boiler.
A Scanning Electron Microscope Study on Agglomeration in Petroleum Coke-Fired FBC Boiler
Authors: Iribarne J. V. , Anthony E. J. , Iribarne A.
Published: January 2009

Ten samples, from different FBC boiler systems burning petroleum coke, were chosen to study the development, structure and composition of deposits formed by agglomeration at various locations in the boilers. The work focused on examination of the samples by scanning electron microscopy (SEM) and dispersive X-ray analysis (EDX). Chemical analysis and other techniques were also employed. The results obtained have not brought to light any evidence of the participation of the liquid phase or of vanadium or alkaline metal compounds. The CaSO4 of the deposits is high (80 to 100%) and the agglomeration results from the prolonged sintering of CaSO4 particles, until a strong 3-dimensional framework is formed, in which other, unrelated particles may be trapped, without contributing to cohesion. While CaO is still available, “chemical sintering” associated with its conversion to CaSO4 appears to be important, but sintering also occurs by a slower mass transfer mechanism and continues after the depletion of CaO. Deposits formed in regions only reached by fly ash (convection section), and also in-bed deposits, grow from particles <50 μm, mostly very small ones, < 10 μm. Where the bed ash can collect (e.g., J-valves), the deposits grow by the sintering together of larger particles, 100–300 μm, which themselves appear to be conglomerates of smaller particles sintered together.
Rheological Properties of Coal-Water Paste for Pressurized Fluidized Bed Combustor
Authors: Lu Ping , Zhang Mingyao
Published: January 2009

Based on the experimental analyses, the slip phenomenon of CWP flowing in pipes is investigated by tube flow test in different tubes. The origination mechanism and flowing regulation of slip phenomenon in pipes are analyzed and a method of determining the real rheological models of CWP by correcting the influence of the slip is put forward. The results show that all kinds of CWPs behave as the properties of non-Newtonian Herschel-Bulkley fluids in the experimental range and the optimum ratio of coarse powders to the fines in CWP for PFBC are determined.
Application of BFB Technology for Biomass Fuels: Technical Discussion and Experiences From Recent Projects
Authors: Hulkkonen Seppo , Fabritius Marko , Enestam Sonja
Published: January 2009

Bubbling fluidized bed combustion (BFB) is well applicable to biomass and other alternate fuels. Typical features for these fuels are high volatile content, varying moisture content and, in some cases, a somewhat high alkali and chlorine content. Fortum Engineering has supplied several boiler and power plants based on its in-house BFB boiler technology. The boilers show good performance with high availability and long operating time.
Modeling Homogeneous Combustion in Bubbling Beds Burning Liquid Fuels
Authors: Faravelli Tiziano , Frassoldati Alessio , Ranzi Eliseo , Miccio Francesco , Miccio Michele
Published: January 2009

This paper presents a first implementation of a model for the description of homogeneous combustion of different fuels in fluidized bed combustors (FBC) at temperatures lower than the classical value for solid fuels, i.e. 850°C. Model construction is based on a key feature of the bubbling fluidized bed: a fuel-rich (endogenous) bubble is generated at the fuel injection point, travels inside the bed at constant pressure and undergoes chemical conversion in presence of mass transfer with the emulsion phase and of coalescence with air (exogenous) bubbles formed at the distributor and, possibly, with other endogenous bubbles. The model couples a fluid-dynamic sub-model based on the two phases theory of fluidization with a sub-model of gas phase oxidation. To this end, model development takes full advantage of a detailed chemical kinetics scheme, which includes both the low and high temperature mechanisms of hydrocarbon oxidation and accounts for about 200 molecular and radical species involved in more than 5000 reactions. Simple hypotheses are made to set-up and close mass balances of the various species as well as enthalpy balances in the bed. First, conversion and oxidation of gaseous fuels (e.g. methane) have been calculated as a test case for the model; then, n-dodecane has been taken into consideration to simply represent a diesel fuel by means of a pure hydrocarbon. Model predictions qualitatively agree with some evidences coming from experimental data reported in the literature. The fate of hydrocarbon species is extremely sensitive to temperature changes and oxygen availability in the rising bubble. A preliminary model validation has been attempted against the results of experiments carried out on a pre-pilot, bubbling combustor fired with underbed injection of a diesel fuel. In particular, model results confirm the trends that the heat release either in the bed or in the freeboard experimentally shows as a function of bed temperature. At lower emulsion phase temperatures many combustible species leave unburned the bed, post-combustion occurs past the bed and freeboard temperature considerably increases; as it is well known, this is an undesirable feature from the viewpoints of practical application and emission control.
Co-Combustion of Animal Waste in Fluidised Bed Boilers: Operating Experiences and Emission Data
Authors: Sva¨rd Solvie Herstad , Backman Stig , Kullendorff Anders , Tilly Hans-A˚ke , Virta Leo , Sternga˚rd Egon
Published: January 2009

Crushed animal waste, given the trade name Biomal, has successfully been combusted in Fluidized Bed Boilers with low emission data. About 500 tons of Biomal were co-combusted in full scale tests in commercial boilers with wood chips, peat and sorted municipal waste. The mixing ratios varied between 30% and 65% depending on the fuel mix. In order to minimize the spread of BSE-infection among cattle a new EU legislation became effective in October 2000. This regulation stipulates that animal waste such as carcasses and SRM (Specific Risk Material) from slaughterhouses has to be destroyed by combustion. The company Konvex AB, which in Sweden is responsible for taking care of this type of animal waste, has together with S.E.P. (Scandinavian Energy Project AB) developed a cost effective concept for using animal waste as a fuel without first processing it into fat and meat meal. The Biomal fuel has been continuously co-combusted for 7 days in a 12 MWth bubbling fluidized bed boiler and for 3 days in a 40 MWth circulating fluidized bed boiler with very good operating performance. During the test periods ordinary emission data such as CO, SO2, NOx, TOC etc. as well as specific compounds such as Dioxins and heavy metals were measured recorded. All data including operating parameters in the EU regulation for co-combustion of waste, EU 2000/76/EG, were met. The CO-levels were below 50 mg/m3n and the TOC-levels were most of the time undetectable and well below 10 mg/m3n. • Despite a much higher nitrogen content in the Biomal fuel compared to wood chips the NOx-emissions were unaffected or in some chases reduced by up to 50% while firing Biomal. • No increased Dioxin emission where measured.
The Largest CFB Boiler (440t/h) in China and Power Station Design
Authors: Qiao Yanqi
Published: January 2009

Xinxiang Thermal Power Plant Construction Project adopts the first largest set of CFB boiler. The paper makes an introduction to its characteristics in practical use. The boiler has the proper construction, advanced technique, complete function and reliable operation after technological improvements in abrasion proof, desulfurizing, jellaba, high–temperature cyclone separator, ash cooler and combustor. The paper also discuss on the unfeasible side bunker program, optimum design on span of deaerator and coal bunker bay, no adoption of independent control building and whole platform on the operating floor of boiler, no enclosure below boiler operating floor in detail. It greatly decreased the project cost on the premise of safety and economic operation.
An Intelligent Tool for Evaluating Bids for Circulating Fluidized Bed Boilers
Authors: Basu P. , Dutta A. , Miller L.
Published: January 2009

Circulating fluidized bed (CFB) boilers have gained wide scale acceptance in both the process and utility industries in sizes up to 300 MWe. Their ability to burn opportunity fuels such as petroleum coke has carved out a special niche for CFB boilers in the energy market. Presently more than 600 CFB boilers are either in operation or under construction worldwide. Boiler purchasers have a much wider choice of available designs and manufacturers to choose from, making bid selection more difficult. Even with performance guarantees in place, it is prudent for buyers to evaluate proposed designs in order to fully appreciate the various options and to identify potential problems. CFBCAD© is an intelligent software developed by extensive research into design methodologies for CFB boilers and critical analysis of the design of many CFB boilers manufactured by different companies around the world. The model used considers user-inputted fuel specifications and steam conditions, and performs sizing calculations for the furnace and heat transfer surfaces. A variety of heat transfer surface configurations are available for analysis. It has been used to evaluate the design of some operating plants and to try and predict deviations from design parameters.
Petroleum Coke FBC Ash: A Detailed Look at Calcium in the Ash
Authors: Anthony E. J. , Jia L. , Burwell S. M.
Published: January 2009

Petroleum coke combustion is different from coal and its behaviour in an FBC environment clearly illustrates this. Analysis of bed ash from the CFBC boilers owned and operated by the Nelson Industrial Steam Company Ltd. (NISCO) was examined in detail to determine the fate of calcium in the ash using a range of techniques. These analyses have shown a free lime content, which is significantly lower than expected based on the elemental analysis of the bed material. Using different methods of analyses than have been typically used for FBC ashes (coal in particular) it would appear that between 6 to 7% of the total CaO in the samples is combined in the form of acid soluble and insoluble other calcium compounds (OCC). This translates to about 30% less free lime (depending on the ash sulfur content) in the sample than would be calculated based on a standard chemical analysis of the bed ash. This current work has identified about 1% of the missing CaO in the form of acid insoluble Ca and Mg vanadates with perhaps as much as 2% of the remaining missing CaO present as soluble OCC.
Advanced Hydrogen Fuel Systems for Fuel Cell Vehicles
Authors: Abele Andris R.
Published: January 2009

On-board storage and handling of hydrogen continues to be a major challenge on the road to the widespread commercialization of hydrogen fuel cell vehicles. QUANTUM Fuel Systems Technologies WorldWide, Inc. (QUANTUM) is developing a number of advanced technologies in response to the demand by its customers for compact, lightweight, safe, robust, and cost-effective hydrogen fuel systems. QUANTUM approaches hydrogen storage and handling as an engineered system integrated into the design of the vehicle. These engineered systems comprise advanced storage, regulation, metering, and electronic controls developed by QUANTUM. In 2001, QUANTUM validated, commercialized, and began production of lightweight compressed hydrogen storage systems. The first commercial products include storage technologies that achieved 7.5 to 8.5 percent hydrogen storage by weight at 350 bar (5,000 psi). QUANTUM has also received German TUV regulatory approval for its 700 bar (10,000-psi) TriShield10™ hydrogen storage cylinder, based on hydrogen standards developed by the European Integrated Hydrogen Project (EIHP). QUANTUM has patented an In-Tank Regulator for use with hydrogen and CNG, which have applications in both fuel cell and alternative fuel vehicle markets. To supplement the inherent safety features designed into the new 700 bar storage tank, QUANTUM’s patented 700 bar In-Tank Regulator provides additional safety by confining the high pressure in the tank and allowing only a maximum delivery pressure of 10 bar (150-psi) outside the storage system. This paper describes initial applications for these hydrogen fuel systems, which have included fuel cell automobiles, buses, and hydrogen refueling stations.
Heat and Mass Transfer and Two Phase Flow in Hydrogen Proton Exchange Membrane Fuel Cells and Direct Methanol Fuel Cells
Authors: Guo Hang , Ma Chong Fang , Wang Mao Hai , Yu Jian , Liu Xuan , Ye Fang , Wang Chao Yang
Published: January 2009

Fuel cells are related to a number of scientific and engineering disciplines, which include electrochemistry, catalysis, membrane science and engineering, heat and mass transfer, thermodynamics and so on. Several thermophysical phenomena such as heat transfer, multicomponent transport and two phase flow play significant roles in hydrogen proton exchange membrane fuel cells and direct methanol fuel cells based on solid polymer electrolyte membrane. Some coupled thermophysical issues are bottleneck in process of scale-up of direct methanol fuel cells and hydrogen proton exchange membrane fuel cells. In present paper, experimental results of visualization of condensed water in fuel cell cathode microchannels are presented. The equivalent diameter of the rectangular channel is 0.8mm. Water droplets from the order of 0.08mm to 0.8mm were observed from several different locations in the channels. Several important problems, such as generation and change characteristics of water droplet and gas bubble, two phase flow under chemical reaction conditions, mass transfer enhancement of oxygen in the cathode porous media layer, heat transfer enhancement and high efficiency cooling system of proton exchange membrane fuel cells stack, etc., are discussed.
System Integration for PEM Fuel Cell With Water and Heat Recovered
Authors: Yan Y. Y. , Chen G. S. , Chiang S. C. , Chu H. S. , Tsu F. S. , Tsay K. C. , Chen F. , Shyu R. J.
Published: January 2009

A 1 kW proton exchange membrane (PEM) fuel cell power system with heat and water recovery was successfully integrated. This power generation system is designed for the stationary application. The waste heat can be recovered into hot water, which store in a tank with temperature higher than 60°C. This hot water may be suitable for bath and kitchen use in a small family. The adjustment for the power generation system is now on going and promoting. Now 38% in the electrical efficiency (AC110V output) for the system is achieved. With waste heat recovery involved, the system will potentially have overall energy efficiency more than 70%. In order to optimize the system, some technologies should be studied and pre-tested before integration work, which mainly included water management for the fuel cell stack, water and thermal conditions on the performance of fuel cell, air and water pumping power needed for the fitting of optimum system performance.
Time-of-Use Monitoring of U.S. Coast Guard Residential Water Heaters With and Without Solar Water Heating in Honolulu, HI
Authors: Walker Andy , Christensen Craig , Yanagi Glen
Published: January 2009

A combination of high energy costs, uniform solar resource, and an active solar industry combine to make Hawaii a good location for cost effective applications of solar water heating. The non-freezing climate allows for simple solar water heating system designs. In the mild climate of Hawaii, solar water heating can displace a large fraction of a home’s electricity use since heating and cooling loads are small. In 1998, sixty-two solar water heaters were installed at Kiai Kai Hale US Coast Guard Housing Area in Honolulu, HI as a pilot project under a grant from the US DOE Federal Energy Management Program (FEMP). The systems are active, open loop systems with a single tank (electric water heater with the bottom element disabled). An assessment of these pilot units will help inform a Coast Guard decision regarding implementing solar water heating on the remaining 256 units in the housing area, and may be useful information for other government and utility programs. On 25 houses with solar water heating and 25 identical houses without solar, instruments were installed to measure on/off cycles of the electric water heaters and the tank outlet temperature. This paper describes the results the monitoring for a six week period From June 11 to July 25, 2002, with a statistical extrapolation to estimate annual savings. Demand savings are estimated at 1.62 kW/house, energy savings at 3,008 kWh/house/year, and annual cost savings per house is estimated at $380/year due to solar. For a system cost of $3,200 ($4,000 minus a $800 utility rebate) and a 25 year present worth factor of 17.1, the savings to investment ratio (SIR) is 2.03, so this solar water heating application is cost effective according to Federal regulation 10CFR436 (which requires SIR>1.0). The annual solar fraction is estimated at 74% and annual solar water heating system efficiency is estimated at 24%. This paper describes the statistical design of the survey; the measured load profiles; the energy, demand, and cost savings; and the observed condition of the systems. The paper includes a discussion of application of the International Performance Measurement and Verification Protocol (IPMVP) applied to renewable energy systems.
Performance Evaluation and Economic Analysis of a Grid Connected Photovoltaic System in a Multi-Family Residential Building
Authors: Shahbazi Abolghasem , Turner Carolyn , Singh Harmohender , Fitzpatrick Shawn
Published: January 2009

A 2 kW photovoltaic (PV) system with battery storage for emergency power supply was designed and installed as a test demonstration in a 112 square meter apartment. The system was installed to demonstrate the potential of a photovoltaic system (using thin-film solar modules) as an environmentally friendly and renewable source of energy compared to conventional electricity generation. Barriers to installation and preliminary estimations of system performance and costs are presented.
Experimental Investigation of the Solar Carbothermic Reduction of ZnO Using a Two-Cavity Solar Reactor
Authors: Osinga T. , Frommherz U. , Steinfeld A. , Wieckert C.
Published: January 2009

Zinc production by solar carbothermic reduction of ZnO offers a CO2 emission reduction by a factor of 5 vis-a´-vis the conventional fossil-fuel-based electrolytic or Imperial Smelting processes. Zinc can serve as a fuel in Zn-air fuel cells or can be further reacted with H2O to form high-purity H2. In either case, the product ZnO is solar-recycled to Zn. We report on experimental results obtained with a 5 kW solar chemical reactor prototype that features two cavities in series, with the inner one functioning as the solar absorber and the outer one as the reaction chamber. The inner cavity is made of graphite and contains a windowed aperture to let in concentrated solar radiation. The outer cavity is well insulated and contains the ZnO-C mixture that is subjected to irradiation from the inner graphite cavity. With this arrangement, the inner cavity protects the window against particles and condensable gases and further serves as a thermal shock absorber. Tests were conducted at PSI’s Solar Furnace and ETH’s High-Flux Solar Simulator to investigate the effect of process temperature (range 1350–1600 K), reducing agent type (beech charcoal, activated charcoal, petcoke), and C:ZnO stoichiometric molar ratio (range 0.7–0.9) on the reactor’s performance and chemical conversion. In a typical 40-min solar experiment at 1500 K, 500 g of a ZnO-C mixture were processed into Zn(g), CO, and CO2. Thermal efficiencies of up to 20% were achieved.
Operation and Preliminary Performance of the Duke Solar Power Roof™: A Roof-Integrated Solar Cooling and Heating System
Authors: Gee Randy , Cohen Gilbert , Greenwood Ken
Published: January 2009

The first commercial-scale Duke Solar Power Roof™, a roof-integrated solar cooling and heating system, began operation in Raleigh, North Carolina in late July 2002. This system is designed to provide 176 kW (50 ton) of solar-driven space cooling using a unique nonimaging concentrating solar collector. The measured performance of the system during its first months of operation is reported here, along with a description of the design and operation of this system.
Solar Upgrading of Methanol: Driven Combined Cycle Using Middle Temperature Solar Collectors
Authors: Jin Hongguang , Hong Hui , Ji Jun , Wang Zhifeng , Cai Ruixian
Published: January 2009

In this paper, we have proposed a novel solar–driven combined cycle with solar upgrading of methanol in middle temperature solar collectors, and investigated the effects of integration of solar thermal energy and methanol decomposition on the performance of the proposed cycle. The process of solar upgrading methanol is a catalytically endothermic decomposition reaction and proceeds in a range of 130–250° C. As a result, the proposed cycle has a breakthrough performance, with net solar–to–electric efficiency of 32.93% at the collector temperature of 220° C, and the turbine inlet temperature of 1062° C, superior to that of the present advanced cycle (REFOS of 20%). The exergy loss in indirect combustion of methanol proposed here is 7.5 percent points lower than that of the direct combustion. The optimum pressure ratio for thermal efficiency is approximately equal to 14. A key point emphasized here is that the proposed new cycle can utilize middle–temperature solar collector with lower cost. The promising results obtained here indicated that this novel solar–driven combined cycle could make a breakthrough in field of solar thermal power generation through integration of solar thermal energy and effective use of synthetic clean fuel.
Multi-Tower Line Focus Fresnel Array
Authors: Mills David R. , Morrison Graham , le Lievre Peter
Published: January 2009

As an alternative to conventional tracking trough systems, one may use line focus Fresnel reflector systems. Before the current Australian work, each field of Fresnel reflectors was directed to a single tower. However, efficient systems of very high ground utilisation can be set up if a field of reflectors uses multiple receivers on different towers (Mills and Morrison, 1999). This paper describes an Australian line focus system, called the Compact Linear Fresnel Reflector (CLFR) system and a project to produce an initial 25MWe solar array. The array will be used as a retrofit preheater for a coal fired generating plant. Future use of such arrays as stand alone high capacity factor powerplants in New South Wales are discussed.
Advanced Hydrogen Generation With Concentrated Solar Power Systems
Authors: Tamme Rainer , Buck Reiner , Mo¨ller Stephan
Published: January 2009

Two renewable approaches to advanced solar supported hydrogen generation are presented. For the near and midterm, Hydrogen from solar reforming might be a viable, and economic approach. For the long-term, hydrogen generated by solar supported electrolysis of water will hold great promise for clean hydrogen production.
Electron Exposure Measurements of Candidate Solar Sail Materials
Authors: Albarado Tesia L. , Hollerman William A. , Edwards David , Hubbs Whitney , Semmel Charles
Published: January 2009

Solar sailing is a unique form of propulsion where a spacecraft gains momentum from incident photons. Since sails are not limited by reaction mass, they provide continual acceleration, reduced only by the lifetime of the lightweight film in the space environment and the distance to the Sun. Practical solar sails can expand the number of possible missions that are difficult by conventional means. The National Aeronautics and Space Administration’s Marshall Space Flight Center (MSFC) is concentrating research into the utilization of ultra lightweight materials for spacecraft propulsion. Solar sails are generally composed of a highly reflective metallic front layer, a thin polymeric substrate, and occasionally a highly emissive back surface. The Space Environmental Effects Team at MSFC is actively characterizing candidate sails to evaluate the thermo-optical and mechanical properties after exposure to electrons. This paper will discuss the preliminary results of this research.
Studies of Heat Pumps Using Direct Expansion Type Solar Collectors
Authors: Ito Sadasuke , Miura Naokatsu , Takano Yasushi
Published: January 2009

A photovoltaic and thermal hybrid panel which was made of an aluminum roll -bond panel with a photovoltaic module on the surface was developed recently for use as an evaporator of a heat pump for residential hot water supply and room heating.1) Pressure loss of the refrigerant at the evaporator was large. Therefore, in the present study, shapes of the inlet and the outlet of the panel were modified to reduce pressure loss; also, thermal performance of the heat pump which adopted three evaporator panels connected in series was examined. Total area of the panels was about 1.9 m2 and the rated capacity of the compressor was 250 W. These modifications reduced pressure loss and improved thermal performance. The effect of the location of the feeler bulb on performance of the heat pump was also examined. It was inferred that the feeler bulb fixed on the tube at the outlet of the evaporator should be as close as possible to the evaporator outlet.
Solar Water Purification by Pasteurization
Authors: Duff William S. , Hodgson David
Published: January 2009

A new passive solar water pasteurization system has been designed, built and tested. The system contains no valves and regulates flow based on the density difference between two columns of water. The new system eliminates boiling problems encountered in previous designs. Boiling is undesirable because it may contaminate treated water. The system has produced over 100 liters per day of treated water with a collector area of 0.45m2. Work is ongoing to develop a theoretical understanding of system behavior, to analytically model it and to further improve system performance.
Experimental and Simulation Studies on Photovoltaic/Thermal Hybrid Collectors
Authors: Yoshinaga Mika , Nakamori Yuichi , Miyazaki Takashi , Sagara Mineo , Okumiya Masaya
Published: January 2009

For increasing total efficiency of solar collectors, PV/T hybrid collectors are focused. A number of simulation models for the PV/T hybrid collector have been proposed, but there are few models that checked the relevance by comparison with the actual measurement. Therefore we picked up sheet-tube type hybrid collectors and measured the thermal and electrical outputs in Tsukuba, Japan to compare with calculation results. We focused the Extension Hottel-Whillier model that is proposed by Florschuetz, 1979, as a basic simulation model. Also proposed the Modified Extension Hottel-Whillier model to increase the accuracy of the electrical performance. Both models showed good agreements with the measured thermal collection positively. The Extension Hottel-Whillier model constantly calculated the large electrical output but the Modified model kept it down ideally. Under the low solar radiation, however, there was large error of the electrical output by the limit of the solar cell model.
Performance of Residential PV System Under Actual Field Conditions in Western Part of Japan
Authors: Nakagami Hidetoshi , Ishihara Osamu , Sakai Koji , Tanaka Akio
Published: January 2009

This paper presents the results of survey on 333 grid connected residential PV generation systems in western part of Japan. The average equipment capacity is 3.4kWp. This research yielded the following results. • The electricity generated for a year was in average 938 kWh/kWp/year. • The generated electricity is equivalent to about 45% of the electricity consumption in a residence. • The cause of variation in system performance was analyzed. • The simple prediction method of PV system output was developed. (The prediction accuracy of simulated hourly electricity generation is r2 = 0.87.)
Efficient Optical Couplings for Fiber-Distributed Solar Lighting
Authors: Maxey L. C. , Cates M. R. , Jaiswal S. L.
Published: January 2009

Optical couplings in large core optical waveguides have many similarities with those in conventional optical fibers but pose some unconventional challenges as well. The larger geometry, looser manufacturing tolerances and reduced dimensional stability compound the problems associated with making low-loss couplings in large core waveguides. The individual factors contributing to coupling losses are discussed to develop an understanding of the extant loss mechanisms. Individual methods and materials employed to mitigate the impact of each of the dominant loss mechanisms are discussed in detail. A combination of endface geometry control, axial alignment constraint and refractive index matching are employed to produce highly efficient optical couplings in large core waveguides. The combination of these elements has significantly reduced the insertion losses due to connector couplings. Prior to implementing the current methods losses of 15% and greater were common but these have been reduced to 2%–5% with the current methods.
Retrofit of the McKay Bay Waste-to-Energy Facility
Authors: Schwartz Mark P. , White Thomas M.
Published: January 2009

This paper provides an overview of the City of Tampa’s 1,000-TPD, four-unit McKay Bay Facility which began operations as an incinerator in 1967; was upgraded to a waste-to-energy (WTE) facility (using waste heat boilers) in 1985; and then again retrofitted during a 33-month design, procurement, and construction period, from 1999 to 2001. As the selected project developer for this recent retrofit, Wheelabrator McKay Bay, Inc. (WMBI) chose to design new chute-to-stack units within the space constraints of the existing refuse feed chutes, ground floor slab and bottom ash conveyors. This paper identifies key plant statistics and describes the project scope, schedule, controls, and safety issues. Results of acceptance testing, including air emissions, are reviewed and compared against contractual and permit requirements. The unique challenges faced by the operations staff during the retrofit are discussed in detail. Several examples of “lessons learned” regarding design and operations are given.
Integrated Management of Solid Wastes for New York City
Authors: Themelis Nickolas J.
Published: January 2009

This report presents the results of a study that examined alternatives to landfilling the municipal solid wastes (MSW) of New York City. Detailed characterization of the wastes led to their classification, according to materials properties and inherent value, to “recyclable”, “compostable”, “combustible”, and “landfillable”. The results showed that the present rates of recycling (16.6%) and combustion (12.4%) in New York City can be increased by a) implementing an automated, modern Materials Recovery Facility (MRF) that separates the blue bag stream to “recyclables” and “combustibles”, and b) combusting the non-recyclable materials in a Waste-to-Energy (WTE) facility. Combustion of wastes to produce electricity is environmentally much preferable to landfilling. An advanced technology for combustion is that used in a modern Waste-to-Energy plant (SEMASS, Massachusetts) that processes 0.9 million metric tons of MSW per year, generates a net of 610 kWh per metric ton of MSW, recovers ferrous and non-ferrous metals, and has lower emissions than many coal-fired power plants.
Application of MSW Gasification Projects in the Caribbean Basin
Authors: Schilli Joseph W. , Campbell Frank
Published: January 2009

Islands located in the eastern Caribbean must address, like other parts of the World, the following issues: • The management of solid waste and hazardous waste. • The protection of the environment. • Energy supplies.
Advancing Waste to Energy Technology Design and Performance of EPI Fluidized Bed RDF-Fired Power Plants Worldwide
Authors: Murphy Michael L.
Published: January 2009

Energy Products of Idaho has designed and installed numerous waste to energy systems in the United States and Europe, with others currently under development. Among the latest are a number of installations in operation and/or construction in Italy. The systems design have undergone some changes over time to stay ahead of changing regulations performance requirements.
Evaluation of Methods and Protocols for Operation of a CERMS at a Municipal Waste Combustor
Authors: Arienti Mark , Harrington Jeffrey R.
Published: January 2009

Regional Waste Systems (RWS) evaluated protocols and methods for operation of a continuous emission rate monitoring system (CERMS) for its municipal waste combustor (MWC) located in Portland, Maine. This continuous measurement of mass emissions (lb/hr) would be in addition to the existing continuous monitoring of the concentration (ppm) of NOx, SO2, and CO emissions using a continuous emissions monitoring system (CEMS) as required of RWS and all other MWC facilities under federal and state rules. The study of CERMS protocols and methods identified the individual components required for a CERMS, evaluated existing methods of measuring MWC unit load and of ensuring “good combustion”, identified and evaluated the existing continuous monitoring regulatory requirements for MWCs and other major sources, evaluated the state of the practice for the use of CERMS, evaluated CERMS data quality, and identified and evaluated existing protocols for CERMS. Finally, a protocol was developed for trial operation of the CERMS considering the above evaluations.
TURBOSORP®: Emission Limits After 17th BimSchV (German Federal Immission Act) at Lowest Costs in a Simple Dry Process — Comparison of Dry/Semi Dry Processes and Results of Mercury and Dioxin Separation in a One Step Process
Authors: Reissner H. K. , Brunner C. , Ba¨rnthaler K.
Published: January 2009

The TURBOSORP®-process is a dry flue gas cleaning process to remove certain pollutants like SO2, HCl, Hg, heavy metals, dioxins and furans. The main principle of this process is to bring flue gas in an intensive contact with Ca(OH)2, open hearth furnace coke, water and recirculated material in the Turboreactor. The Turboreactor operates as circulating fluidized bed in the manner of fast fluidisation. The gas/solid mixture leaves the Turboreactor at the top and the solids are separated in a fabric filter from the flue gas. More than 99% of the separated solids are recirculated to the Turboreactor and the rest leaves the process as product. Due to the high sorbent recirculation percentage a high sorbent utilization and low stoechiometric rates are reached in the TURBOSORP®-process. Due to the fact to have plants in operation for the spray absorption and for the TURBOSORP® process, a comparison definitely showed advantages for the TURBOSORP® process. Experiences of the plant start up of a TURBOSORP® plant in Poland concerning optimisation in pressure loss and hydrodynamics of the Turboreactor using CFD-Simulation are presented. Results concerning mercury and dioxin separation in our Turbosorp® pilot plant after the refuse incinerator MV Spittelau, Vienna, are discussed.