Bioresource and Agricultural Engineering Commons^™

Compositional Variations In Pilot Gasifier And Laboratory-Produced Slags And Their Impacts On Slag Viscosity And Coal Assessment, Alexander Ilyushechkin, Daniel Roberts, David Harris

Coal Combustion and Gasification Products Journal Archive

The flow behaviour of coal mineral matter at high temperatures is an important parameter for coal use in entrained-flow gasification technologies. Recently, gasification performance data was obtained from a series of pilot-scale gasification tests on a suite of well-characterised Australian black coals. Evaluation of the results of the pilot tests and the detailed laboratory investigations provided the opportunity for evaluation of the practical applicability of different laboratory and modelling techniques for coal assessment in terms of mineral matter behaviour in entrained flow gasification. A series of viscosity measurements was made over the range 1200–1600uC using slags produced in a pilot …

Compaction Of High-Ca Fly Ash-Al- And Al-Alloy-Composites: Evaluation Of Their Microstructure And Tribological Performance, Grigorios Itskos, Angeliki Moutsatsou, Pradeep K. Rohatgi, Nikolaos Koukouzas, Charalampos Vasilatos, Eleni Katsika

Coal Combustion and Gasification Products Journal Archive

In this study, highly calcareous and siliceous fly ash particles were utilized for the fabrication of Al- and Al-alloy-based MetalMatrix Composites (MMCs) by means of powder metallurgy. After compacting and sintering Al and Al/Si powders containing 10, 15, and 20wt. % ash particles, the homogenous (and with minimal amount of voids) microstructure of the produced composites was verified by means of Scanning Electron Microscopy (SEM). The composites were tested for their dry sliding wear behavior using a pin-on-disc machine against spheres of alumina. The worn surfaces of composites were then examined by using SEM and Energy Dispersive X-Ray Spectroscopy (EDS). …

Influence Of Chemical Reagents On Rheological Properties Of Fly Ash-Water Slurry At Varying Temperature Environment, H.K. Nail, M.K. Mishra, Karanam U.M. Rao

Coal Combustion and Gasification Products Journal Archive

About 70% of total electrical energy is generated from thermal power plants in India which in turn release about 160 Mt of fly ash as solid waste annually. Transportation and disposal of such a huge amount of fly ash is a major problem faced by the power plants. Presently fly ash is transported as lean slurry in pipe lines requiring about 80 to 85% of water with high energy input. A major impediment in high volume transportation of fly ash is its high specific gravity as compared to that of water. The objective of the present study was to evaluate …

Impact Of Manufactured Coal Ash Aggregates On Water Quality During Open Pit Restoration: 1. A Statistical Screening Test, Sangchul Hwang, Isomar Latorre

Coal Combustion and Gasification Products Journal Archive

Utilization of manufactured coal ash aggregates (MAs) as a subsoil substitute during restoration of an open pit was assessed in a three-factor, two-level factorial analysis. The factors of interest were the MA application rate (2:1 or 1:2 topsoil/MA volume ratio), rainfall intensity (high or low), and aggregate size (2.36–4.75 mm or 4.75–9.53 mm). Among the water quality parameters examined (pH, turbidity, heavy metal content (lead and cadmium), conductivity, and hardness), the last two parameters were significantly higher (p,0.05) in soil amended with MAs than in a control reactor using sand. A low rainfall intensity and larger aggregate size resulted in …

The Leachability Of Major Elements At Different Stages Of Weathering In Dry Disposed Coal Fly Ash, S.A. Akinyemi, A. Akinlua, W.M. Gitari, R.O. Akinyeye, L.F. Petrik

Coal Combustion and Gasification Products Journal Archive

Large quantities of solid residue are generated by coal-fired power stations in many parts of the World. The disposal and management of the unused fly ash remains a major problem to the environment. The weathered dry disposed ash cores comprise of major element constituents such as Al, Si, Ca, Mg, Fe, Mn, Na+ and K+. The mobility patterns and mineralogical associations of major elements in weathered dry disposed ash dumps aged 1-year-old, 8-year-old and 20-year-old from a coalfired power station in South Africa were investigated using a modified sequential extraction scheme. The extraction sequence was as follows: (1) water soluble, …

Feasibility Of Wastewater Reuse For Fish Production In Small Communities In A Developing World Setting, Joshua James Girard

USF Tampa Graduate Theses and Dissertations

Eradicating poverty, malnutrition, and the burden of disease have been included as three of the major issues facing the world. The United Nation member countries, having set forth the Millennium Development Goals, have committed themselves to solving these problems. Two major factors which affect solutions to these problems are increasing water stress and implementing improved sanitation. Integration of tilapia aquaculture and reuse of wastewater has been suggested as a solution which addresses both of these factors. The objective of this study is to examine the feasibility, and explore the benefits and drawbacks, to implementing small community wastewater fed (WWF) aquaculture …

Improved Soil Mixing And Delivery System For A Storm Runoff Simulator, William C. Alms, Thomas G. Franti, David P. Shelton

Department of Agricultural and Biological Systems Engineering: Faculty Publications

An earlier version of a storm runoff simulator to test conservation buffers reproduced target hydrographs and sedigraphs using uniform, fine sand; however, it was unable to uniformly mix and deliver native sediment. The objectives of this work reported were to create a method to process native agricultural sediment, mix a uniform sediment slurry at a target concentration, and create a control system that will deliver the slurry in varying flow rates corresponding to a target sedigraph. Eroded silty clay (14% sand) was scraped, dried, and processed with a hammer mill. A sand (93% sand) and loam (44% sand) were dried …

Irrigation Efficiency And Uniformity, And Crop Water Use Efficiency, Suat Irmak, Lameck O. Odhiambo, William L. Kranz, Dean E. Eisenhauer

Department of Agricultural and Biological Systems Engineering: Faculty Publications

This Extension Circular describes various irrigation efficiency, crop water use efficiency, and irrigation uniformity evaluation terms that are relevant to irrigation systems and management practices currently used in Nebraska, in other states, and around the world. The definitions and equations described can be used by crop consultants, irrigation district personnel, and university, state, and federal agency personnel to evaluate how efficiently irrigation water is applied and/or used by the crop, and can help to promote better or improved use of water resources in agriculture.

As available water resources become scarcer, more emphasis is given to efficient use of irrigation water …

A Case Study Concerning The Effects Of Controller Response And Turning Movements On Application Rate Uniformity With A Self-Propelled Sprayer, Joe D. Luck, A. Sharda, Santosh Pitla, J. P. Fulton, S. A. Shearer

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The use of precision agriculture technologies such as automatic boom section control allows producers to reduce off-target application when applying herbicides. While automatic boom section control provides benefits, pressure differences across the spray boom resulting from boom section actuation may lead to off-rate application errors. Off-rate errors may also result from spray rate controller compensation for ground speed changes or velocity variation across the spray boom during turning movements. This project focused on characterizing application rate variation for three fields located in central Kentucky. GPS coordinates, boom control status, and nozzle pressure data (at 15 nozzle locations) were recorded as …

Optimization And Economic Evaluation Of Industrial Gas Production And Combined Heat And Power Generation From Gasification Of Corn Stover And Distillers Grains, Ajay Kumar, Yaşar Demirel, David D. Jones, Milford Hanna

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Thermochemical gasification is one of the most promising technologies for converting biomass into power, fuels and chemicals. The objectives of this study were to maximize the net energy efficiency for biomass gasification, and to estimate the cost of producing industrial gas and combined heat and power (CHP) at a feedrate of 2,000 kg/h. Aspen Plusbased model for gasification was combined with a CHP generation model, and optimized using corn stover and dried distillers grains with solubles (DDGS) as the biomass feedstocks. The cold gas efficiencies for gas production were 57% and 52%, respectively, for corn stover and DDGS. The selling …

Nebraska Agricultural Water Management Demonstration Network (Nawmdn): Integrating Research And Extension/Outreach, Suat Irmak, Jennifer M. Rees, Gary L. Zoubek, Brandy S. Van Dewalle, William R. Rathje, Rodney Debuhr, Dan Leininger, Darrel D. Siekman, James W. Schneider, Andrew P. Christiansen

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Maximizing the net benefits of irrigated plant production through appropriately designed agricultural water management programs is of growing importance in Nebraska, and other western and Midwestern states, because many areas are involved in management and policy changes to conserve irrigation water. In Nebraska, farmers are being challenged to practice conservation methods and use water resources more efficiently while meeting plant water requirements and maintaining high yields. Another challenge Nebraska experiences in it's approximately 3.5‐million‐ha irrigated lands is limited adoption of newer technologies/tools to help farmers better manage irrigation, conserve water and energy, and increase plant water use efficiency. In 2005, …

On The Dynamics Of Canopy Resistance: Generalized Linear Estimation And Relationships With Primary Micrometeorological Variables, Suat Irmak, Denis Mutiibwa

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The 1‐D and single layer combination‐based energy balance Penman‐Monteith (PM) model has limitations in practical application due to the lack of canopy resistance (r_c) data for different vegetation surfaces. r_c could be estimated by inversion of the PM model if the actual evapotranspiration (E_Ta) rate is known, but this approach has its own set of issues. Instead, an empirical method of estimating r_c is suggested in this study. We investigated the relationships between primary micrometeorological parameters and rc and developed seven models to estimate r_c for a nonstressed maize canopy on an hourly …

Nebraska Water And Energy Flux Measurement, Modeling, And Research Network (Nebflux), Suat Irmak

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Surface energy and water vapor fluxes play a critical role in understanding the response of agro‐ecosystems to changes in environmental and atmospheric parameters. These fluxes play a crucial role in exploring the dynamics of water and energy use efficiencies of these systems. Quantification of the fluxes is also necessary for assessing the impact of land use and management changes on water balances. Accomplishing these goals requires measurement of water vapor and energy exchanges between various vegetation surfaces and microclimates for long‐enough periods to understand the behavior and dynamics involved with the flux transfer so that robust models can be developed …

Testing Of Interactions Between Coal Ash Leachates And Rock Materials For Mine Backfill Evaluations, Colin R. Ward, David French, Leanne Stephenson, Ken Riley, Zhongsheng Li

Coal Combustion and Gasification Products Journal Archive

A series of laboratory-based leaching tests has been developed to evaluate the chemical interaction between ash, water and different mine-site rock materials, as a basis for assessing the potential environmental impact of using coal ash as backfill in coal mines. Two different test protocols were used: a two-stage serial batch testing program in which leachate from representative ash samples were allowed to interact separately with relevant rock materials under laboratory conditions, and a single-stage mixed batch testing program in which 50:50 mixtures of the same ashes and rock samples were extracted with water following a similar procedure to leaching tests …

Chemistry Of Coal And Coal Combustion Products From Kentucky Power Plants: Results From The 2007 Sampling, With Emphasis On Selenium, James C. Hower, Thomas L. Robl, Gerald A. Thomas, Shelley D. Hopps, Margaret Grider

Coal Combustion and Gasification Products Journal Archive

Kentucky produced over 8 Mt of coal combustion products (CCPs) in 2006, with 30% of the CCPs being utilized, a significant increase from our 1996 and 2001 surveys. As much of the increase is related to increased utilization of flue-gas desulfurization (FGD) gypsum, the increased production of FGD gypsum coincident with the commissioning of new FGD units and the saturation of the (currently) weak market for new construction, the percentage of utilization may decrease by the time of the next planned survey (2011). The concentration of volatile trace elements in the feed coal and in the pulverizer reject, while associated …

An Investigation Of The Behavior Of Raw Calcareous Fly Ash In Mortar Mixtures, Ioanna Papayianni, Eleftherios K. Anastasiou

Coal Combustion and Gasification Products Journal Archive

The behavior of unprocessed calcareous fly ash in cement mortar mixtures is often questionable and unpredictable and that is one of the difficulties in confining these fly ashes within the limits of standards. This work aims at correlating the material characteristics with its behavior in mortar mixtures. An effort is made to understand how three of the reactive constituents; lime (CaO), silica (SiO2), and sulfates (SO3), affect strength and volume stability. Two raw calcareous fly ashes of different composition emanating from the Ptolemaida area, Greece, were systematically tested to define their profile as cementitious agents that could be incorporated in …

Coal Fired Power Station Ash Products And Eu Regulation, Lindon K.A. Sear

Coal Combustion and Gasification Products Journal Archive

The UK has a long history of the use of coal fired power station ash products in a range of applications in construction. These range from use in concrete as a cementitious material through to its use as a fill material in embankments. While there have been no environmental problems associated with these uses, environmental regulations emanating from the European Union (EU) are increasingly impacting on the use of these materials. Unfortunately it is not a single set of regulations that are being applied, but three separate and apparently disconnected initiatives; these are Registration, Evaluation and Authorisation of Chemicals (REACH), …

Enriched Coal Ash Utilization For Augmenting Production Of Rice Under Acid Lateritic Soil, S. Karmakar, B.N. Mittra, B.C. Ghosh

Coal Combustion and Gasification Products Journal Archive

The use of industrial wastes such as fly ash (FA) or rice husk ash (RHA), along with paper factory sludge (PFS), farmyard manure (FYM), and chemical fertilizers (CF), under integrated nutrient management, was studied in acid lateritic soil on rice. Application of combined fertilization sources increased growth, yield attributes, and yield (up to 92.3 and 9.7% over control and CF, respectively) of wet season rice. The uptake of N, P, K, Ca, Mg, Fe, Mn, Zn, Cu, and Co was increased under combined fertilization sources. The study also indicated that such integrated plant nutrition system improved physico-chemical properties of soil …

Erosive Wear In Pipelines At Pneumatic Conveying Of Fine Silicon-Containing Materials, Viacheslav Y. Putilov, Vijay K. Agarwal, Irina V. Putilova

Coal Combustion and Gasification Products Journal Archive

Erosive wear is a major operational problem in conveying of hard abrasive bulk materials like silica sand, fly ash, coal dust, etc., in pneumatic conveying systems. Erosion results in emergency downtime of pneumatic conveying installations of ash and slag removal and dust-preparation systems at TPPs caused by holes in pipelines. That leads to worsening of technical, economic, and ecological parameters of thermal power plants as a whole. In MPEI, a model of estimating erosion of rectilinear and curvilinear sections of pneumatic conveying pipelines has been developed. To validate the estimating model developed in the MPEI, experimental investigations in the Indian …

Evaluation Of The Variables That Influence Mercury Capture In Solid Sorbents, M. Antonia Lopez-Anton, Patricia Abad-Valle, Mercedes Diaz-Somoano, M. Rosa Martinez-Tarazona

Coal Combustion and Gasification Products Journal Archive

Newly obtained results on mercury retention in fly ashes and activated carbons during coal combustion are compared with previous findings. The influence of different variables on mercury capture, including the composition and nature of the sorbents, the composition of the flue gas and the mercury species in gas phase is investigated. Coal-fired utility boilers are currently the largest single-known source of mercury emissions. According to the USEPA’s Information Collection Request (ICR), on average, only 40% of the mercury entering a coal-fired power plant is captured, while 60% is emitted into the atmosphere. Several solid materials, including activated carbons, are considered …

Mechanical Performance Of Pavement Geomaterials Stabilized With Fly Ash In Field Applications, Lin Li, Tuncer B. Edil, Craig H. Benson

Coal Combustion and Gasification Products Journal Archive

This paper describes an evaluation of the mechanical performance of fly ash stabilized materials. Soft clay soil, asphaltic recycled pavement material (RPM), and road-surface gravel (RSG) were stabilized using Class C and off-specification fly ashes to create working platforms or stabilized base courses for construction of flexible and rigid pavements at six sites in Wisconsin and Minnesota. California bearing ratio (CBR), resilient modulus (Mr) tests, and unconfined compression (qu) tests were conducted on the subgrade soil, RPM, and RSG alone and on mixtures prepared in the field and the laboratory to evaluate improvements in bearing resistance and stiffness. Fly ash …

Manufactured Coal Ash Aggregates For Aqueous Tnt Sorption, Sangchul Hwang, Victor Hernandez

Coal Combustion and Gasification Products Journal Archive

No abstract provided.

Mineralogy And Leaching Characteristics Of Coal Ash From A Major Brazilian Power Plant, Luis F.O. Silva, Colin R. Ward, James C. Hower, Maria Izquierdo, Frans Waanders, Marcos L.S. Oliveira, Zhongsheng Li, Rachel S. Hatch, Xavier Querol

Coal Combustion and Gasification Products Journal Archive

The feed coals, fly ashes and bottom ashes collected from seven different units in a major Brazilian PF power plant have been subjected to comprehensive mineralogical, geochemical, and petrographic studies, to investigate the links between feed coal and ash characteristics. Ashes from two of the units were collected while the coal was being co-fired with oil as part of the boiler start-up procedure, allowing the impact of oil co-firing on ash characteristics also to be evaluated. High proportions of unburnt carbon and high proportions of retained sulphur were found in the fly ashes produced during oil co-firing, probably reflecting less …

Precipitation Of Germanium From Coal Fly Ash Leachates, Fatima Arroyo, Constantino Fernandez-Pereira, Pilar Coca

Coal Combustion and Gasification Products Journal Archive

The valorization of a coal gasification fly ash was studied by leaching the fly ash using different aqueous solutions followed by the subsequent precipitation of the germanium solubilized from the ash. Experimental investigations were focused on the precipitation of a germanium2catechol (CAT) complex with cetyl trimethyl ammonium bromide (CTAB). The influences of pH and amounts of CTAB and CAT on the precipitation yield were investigated. To this aim, a central composite rotatable design and ANOVA Design Expert 7.0.3 Wiley software were employed for experimental design and analysis of the results. Thus, the independent and combined effects of pH, CAT/Ge and …

The Effect Of Drag-Reducing Additives On The Rheological Properties Of Fly Ash-Water Suspensions At Varying Temperature Environment, H.K. Naik, M.K. Mishra, Rao Karanam U.M.

Coal Combustion and Gasification Products Journal Archive

Fly ash transportation and disposal is a major problem in India. Presently fly ash is being transported as lean slurry in pipe lines requiring about 80 to 85% of water which, in turn, consumes more energy input. The objective of the present study is to evaluate the rheological characteristics of fly ash slurry at varying temperatures with and without an additive to facilitate smooth flow in the pipelines. Six fly ash slurry samples were prepared from the fly ash obtained from a thermal power plant situated in the southern part of India. The main constituents of the slurry were fly …

Waste Stabilization/Solidification (S/S) Of Eaf Dust Using Fly Ash-Based Geopolymers. Influence Of Carbonation On The Stabilized Solids, Y. Luna Galiano, C. Fernandez Pereira, J. Vale

Coal Combustion and Gasification Products Journal Archive

The effect of the curing in a carbonated ambient of the solids obtained after the stabilization/solidification (S/S) of metallurgical waste using geopolymerization technology is described in this paper. The electric arc furnace (EAF) dust to stabilize contains hazardous metals such as Pb, Cd, Cr, or Zn. Different geopolymeric agents such as potassium hydroxide, potassium silicate, metakaolin, and blast furnace slag have been used. Mixtures of EAF waste with these geopolymeric materials and class F fly ash as main silica and alumina source have been processed. Samples were submitted to an accelerated carbonation test. Compressive strength tests and different leaching tests …

Variations In Fly Ash Composition With Sampling Location: Case Study From A Portuguese Power Plant, B. Valentim, A. Guedes, D. Flores, C.R. Ward, J.C. Hower

Coal Combustion and Gasification Products Journal Archive

Fly ash (FA) is a heterogeneous and complex material resulting from coal combustion in thermoelectric power plants (TPP). Therefore, different types of coals, worldwide, produce FAs with different compositions. However, the location of the FA sampling system, inside the TPP, is also important to the composition of the FA produced at each location. A case study of FA from a Portuguese TPP, using several coal and FA characterization techniques (particle size analysis, proximate and ultimate analyses, XRF, SEM/ESEM/EDS, Optical microscopy, XRD, inferred chemistry, and AAS), has shown that FA chemical classification, mineralogy and phase-mineral classification, and trace elements (Cr, Cu, …

Zeolite Synthesised From Fused Coal Fly Ash At Low Temperature Using Seawater For Crystallization, Claudia Belviso, Francesco Cavalcante, Antonio Lettino, Saverio Fiore

Coal Combustion and Gasification Products Journal Archive

A sample of coal fly ash from an Italian thermoelectric power plant was used in order to synthesize zeolite by hydrothermal activation after a pre-treatment fusion with NaOH. The experiments involved were performed at different temperatures of crystallization, ranging from 35 up to 60uC, with seawater and distilled water, separately, during hydrothermal process. A comparison between the results obtained from the use of the different kinds of water showed that at low temperature (35–40 uC) the synthesis yield of zeolite X is higher using seawater as crystallizing agent than using distilled water. This implies a possible application for seawater in …

2010 Nebraska Water Monitoring Programs Report, Marty Link

Nebraska Department of Environmental Quality: Reports

The Nebraska Department of Environmental Quality (NDEQ) is charged with monitoring, assessing, and to the extent possible, managing the state’s water resources. The purpose of this work is to protect and maintain good quality water and encourage or execute activities to improve poor water quality. Monitoring is done on the over 18,000 miles of flowing rivers and streams, our greater than 280,000 acres of surface water in lakes and reservoirs, and the vast storage of groundwater in Nebraska’s aquifers.

Numerically Predicting Seepage Gradient Forces And Erosion: Sensitivity To Soil Hydraulic Properties, Garey A. Fox, Derek M. Heeren, Glenn V. Wilson, E. J. Langendoen, Amanda K. Fox, Maria L. Chu-Agor

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Research has suggested that streambank seepage can be an important mechanism of bank instability; however, limited information is available on the level of soil characterization necessary to accurately predict seepage gradient forces and erosion. The objective of this research was to quantify the expected range of predicted seepage gradients for various degrees of site characterization. Uncertainty analysis on seepage gradient predictions was performed relative to variability in soil hydraulic properties. A two-dimensional unsaturated/saturated groundwater flow model was used to simulate a homogeneous soil layer for sand and loamy sand soils packed at various bulk densities, ρ_b. A pedotransfer …