Combustion Characteristics of Fuels: Experiment Scale-Up From Bench Scale Reactors to Commercial Scale CFB Boiler

2005 ◽  
Author(s):  
Heidi Ha¨sa¨ ◽  
Ari-Pekka Kirkinen ◽  
Antti Tourunen ◽  
Timo Hyppa¨nen ◽  
Jaakko Saastamoinen ◽  
...  
Keyword(s):  
Dynamic Behavior ◽  
Dynamic Models ◽  
Scale Up ◽  
Combustion Process ◽  
Pilot Scale ◽  
Full Scale ◽  
Small Scale ◽  
Bench Scale ◽  
Precise Knowledge ◽  
Dynamic Experiments

The equipment scale-up towards larger CFB units requires accurate knowledge of the process and combustion behavior of fuels. Unit sizes of 300 MWe are in operation and plans for larger units have been made. Shift from natural circulation to once through steam cycle requires more precise knowledge of the dynamic behavior of the fuel since there is no steam drum. The combustion of inhomogeneous fuels, as well as, special demands for dynamic process behavior poses new challenges to boiler manufactures. Nowadays, dynamic models are used to develop and analyze the dynamic behavior of the combustion process. Testing all the dynamic changes in the full-scale reactor would be both expensive and risky. Therefore, bench and pilot scale experiments, combined with dynamic models of the combustion processes, give a good basis to study behavior of larger scale units. At the same time models also increase knowledge of different process relations. The main objective of this paper is to present results of scale-up experiments from the bench scale, via pilot scale, to full-scale boilers. Further, how the combustion and reactivity of fuels in the full-scale boilers can be studied with the aid of small-scale experiments and simulations. Dynamic experiments were carried out with three reactors of different scale. Calculation and simulation models have been developed to illustrate the combustion in the reactors; e.g. heat release profiles, fuel reactivity and particle size distribution. Results from the dynamic experiments are used to adjust the computer models.

Scale-Up Problems

1982 ◽  
Vol 14 (9-11) ◽  
pp. 1269-1277
Author(s):  
John M Sidwick
Keyword(s):  
Wastewater Treatment ◽  
Scale Up ◽  
Pilot Scale ◽  
Full Scale ◽  
Bench Scale ◽  
Treatment Processes

The paper considers some of the problems of the scale-up of wastewater treatment processes; from bench-scale to pilot-scale, and from pilot-scale to full-scale. An attempt is made to put the question of scale-up problems into perspective by reference to the experience of the author and the work of others reported in the literature.

Model-based evaluation of a new upgrading concept for N-removal

2002 ◽  
Vol 45 (6) ◽  
pp. 169-176 ◽  
Author(s):  
S. Salem ◽  
D. Berends ◽  
J.J. Heijnen ◽  
M.C.M. van Loosdrecht
Keyword(s):  
Mathematical Modelling ◽  
Scale Up ◽  
Treatment Plant ◽  
Ammonia Concentration ◽  
Pilot Scale ◽  
Full Scale ◽  
Model Based ◽  
N Removal ◽  
Quantitative Basis ◽  
Treatment Concepts

Mathematical modelling is considered a time and cost-saving tool for evaluation of new wastewater treatment concepts. Modelling can help to bridge the gap between lab and full-scale application. Bio-augmentation can be used to obtain nitrification in activated sludge systems with a limited aerobic sludge retention time. In the present study the potential for augmenting the endogenous nitrifying population is evaluated. Implementing a nitrification reactor in the sludge return line fed with sludge liquor with a high ammonia concentration leads to augmentation of the native nitrifying population. Since the behaviour of nitrifiers is relatively well known, a choice was made to evaluate this new concept mainly based on mathematical modelling. As an example an existing treatment plant (wwtp Walcheren, The Netherlands) that needed to be upgraded was used. A mathematical model, based on the TUDP model and implemented in AQUASIM was developed and used to evaluate the potential of this bioaugmentation in the return sludge line. A comparison was made between bio-augmentation and extending the existing aeration basins and anoxic tanks. The results of both modified systems were compared to give a quantitative basis for evaluation of benefits gained from such a system. If the plant is upgraded by conventional extension it needs an increase in volume of about 225%; using a bioaugmentation in the return sludge line the total volume of the tanks needs to be expanded by only 75% (including the side stream tanks). Based on the modelling results a decision was made to implement the bioaugmentation concept at full scale without further pilot scale testing, thereby strongly decreasing the scale-up period for this process.

A Scaling-up Approach from Experimental Tunnel to Spray Dryer

2010 ◽  
Vol 6 (1) ◽  
Author(s):  
Xuan-You Li ◽  
Ireneusz Zbicinski ◽  
Jing Wu
Keyword(s):  
Spray Drying ◽  
Scale Up ◽  
Scaling Up ◽  
Pilot Scale ◽  
Drying Kinetics ◽  
Water Evaporation ◽  
Small Scale ◽  
Spray Dryer ◽  
Cfd Modelling ◽  
Initial Water

A scaling-up approach from drying of a thin layer wet material in a experimental tunnel to a pilot scale spray drying was developed through determining drying kinetics of quick evaporation process. Maltodextin was selected as solid material in solution to be dried. Critical moisture contents as a function of initial water evaporation rate (drying rate) shows that there is the same variation between the small scale test tunnel and the pilot scale spray dryer. Result of CFD modelling demonstrates that drying kinetics obtained from the small-scale tunnel could be properly applied to scale-up the spray drying process.

Rejection of organic micropollutants by high pressure membranes: comparison of bench-scale versus single element tests

2006 ◽  
Vol 6 (4) ◽  
pp. 107-116
Author(s):  
T.U. Kim ◽  
C. Bellona ◽  
P. Xu ◽  
J. Drewe ◽  
G. Amy
Keyword(s):  
High Pressure ◽  
Scale Up ◽  
Pilot Scale ◽  
Membrane Properties ◽  
Single Element ◽  
Organic Micropollutants ◽  
Trace Organic Compounds ◽  
Operational Conditions ◽  
Bench Scale ◽  
Trace Organic

There has been considerable information reported on rejection of trace organic compounds from pilot-scale and full-scale experiments with reverse osmosis (RO) and nanofiltration (NF), but this information has limited value in predicting the rejection of these compounds by high-pressure membranes. The goal of this research is to define relationships between compound properties, membrane properties, and operational conditions, e.g. pressure, recovery, affecting trace organic compound rejection, comparing bench-scale recirculation tests and bench-scale single-pass tests. In addition, bench-scale results are compared against single element tests to ascertain scale-up effects.

scholarly journals Assessment of the breakthrough of micropollutants in full-scale granular activated carbon adsorbers by rapid small-scale column tests and a novel pilot-scale sampling approach

2020 ◽  
Vol 6 (10) ◽  
pp. 2742-2751 ◽  
Author(s):  
Tony Merle ◽  
Detlef R. U. Knappe ◽  
Wouter Pronk ◽  
Bernadette Vogler ◽  
Juliane Hollender ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Service Life ◽  
Granular Activated Carbon ◽  
Pilot Scale ◽  
Full Scale ◽  
Small Scale ◽  
Column Tests ◽  
Sampling Approach

This study aimed to compare three approaches for predicting the service life of full-scale GAC adsorbers for the removal of micropollutants.

scholarly journals Comparison of Experimental Results to CFD Models for Blending in a Tank Using Dual Opposing Jets

2011 ◽  
Author(s):  
Robert A. Leishear ◽  
Si Y. Lee ◽  
Mark D. Fowley ◽  
Michael R. Poirier ◽  
Timothy J. Steeper
Keyword(s):  
Liquid Radioactive Waste ◽  
Scale Up ◽  
Pilot Scale ◽  
Full Scale ◽  
Experimental Results ◽  
Cfd Models ◽  
Waste Storage ◽  
Scale Models ◽  
Computational Fluid Dynamics Cfd ◽  
Cooling Coils

Research has been completed in a pilot scale, eight foot diameter tank to investigate blending, using a pump with dual opposing jets. The jets re-circulate fluids in the tank to promote blending when fluids are added to the tank. Different jet diameters and different horizontal and vertical orientations of the jets were investigated. In all, eighty five tests were performed both in a tank without internal obstructions and a tank with vertical obstructions similar to a tube bank in a heat exchanger. These obstructions provided scale models of several miles of two inch diameter, serpentine, vertical cooling coils below the liquid surface for a full scale, 1.3 million gallon, liquid radioactive waste storage tank. Two types of tests were performed. One type of test used a tracer fluid, which was homogeneously blended into solution. Data were statistically evaluated to determine blending times for solutions of different density and viscosity, and the blending times were successfully compared to computational fluid dynamics (CFD) models. The other type of test blended solutions of different viscosity. For example, in one test a half tank of water was added to a half tank of a more viscous, concentrated salt solution. In this case, the fluid mechanics of the blending process was noted to significantly change due to stratification of fluids. CFD models for stratification were not investigated. This paper is the fourth in a series of papers resulting from this research (Leishear, et.al. [1–4]), and this paper documents final test results, statistical analysis of the data, a comparison of experimental results to CFD models, and scale-up of the results to a full scale tank.

Fireside Deposit Formation in Biomass Fired FBC: A Comparison Between Tests Performed in Three Significantly Different Sized Combustors

2003 ◽  
Author(s):  
Bengt-Johan Skrifvars ◽  
Patrik Yrjas ◽  
Mikko Hupa ◽  
Martti Aho ◽  
Jaani Silvennoinen ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Flue Gas ◽  
Pilot Scale ◽  
Full Scale ◽  
Small Scale ◽  
Deposition Rates ◽  
Stable Conditions ◽  
Bubbling Fluidized Bed ◽  
Main Components ◽  
Fluidized Bed Boilers

This paper deals with the prediction of ash related problems in fluidized bed boilers during co-firing of various bio-fuels. A study was performed where the slagging and fouling behavior was monitored in three different sized bubbling fluidized bed combustors, a 20 kW semi-pilot reactor, a 2 MW pilot-scale device and a 105 MW full-scale boiler. The aim of the study was to learn about how well slagging and fouling in a small-scale device compares to a full-scale boiler and to see how well the slagging and fouling can be predicted with a small-scale device. Various types of Scandinavian bio-fuels as well as peat were used both separately and mixed. From all three devices ash and deposit samples were collected during as uniform and stable conditions as possible. The fuels used in the three devices during the test campaigns were carefully chosen so that they would be as similar as possible. Bed, furnace and flue gas temperatures were monitored as well as flue gas emissions. The fuels, ashes and deposits were analyzed on their main components and deposition rates were calculated based on the deposit measurements. These data were finally used for assessing the slagging and fouling propensity of the fired fuel. The paper compares and discusses the results from the three different size classes.

scholarly journals Cross-Flow Ultrafiltration Scaling Considerations

2006 ◽  
Author(s):  
Mark R. Duignan ◽  
Si Y. Lee
Keyword(s):  
Radioactive Waste ◽  
Cross Flow ◽  
Plant Size ◽  
Pilot Scale ◽  
Full Scale ◽  
Radioactive Wastes ◽  
Data Availability ◽  
Small Scale ◽  
Feed Tank ◽  
Filter Performance

One legacy of the nuclear age is radioactive waste and it must be stabilized to be stored in a safe manner. An important part of the stabilization process is the separation of radioactive solids from the liquid wastes by cross-flow ultrafiltration. The performance of this technology with the wastes to be treated was unknown and, therefore, had to be obtained. However, before beginning a filter study the question of experimental scale had to be addressed. Of course, carrying out experiments using full-size equipment is always ideal, but rarely practical when dealing with plant size processes. Flow loops that will handle millions of liters of slurries, which are either highly caustic or acidic, with flow rates of 10,000 lpm make full-scale tests prohibitively expensive. Moreover, when the slurries happen to be radioactive such work is also very dangerous. All of these considerations lend themselves to investigations at smaller scales and in many situations can be treated with computational analyses. Unfortunately, as scale is reduced it becomes harder to provide prototypic results and the two and three phase multi-component mixtures challenge accurate computational results. To obtain accurate and representative filter results two smaller scale filters were chosen: 1. Small-scale – would allow the testing with actual radioactive waste samples and compare results with simulated wastes that were not radioactive. For this scale the feed tank held 6 liters of waste and it had a single cross-flow filter tube 0.61 m long. 2. Pilot-scale – would be restricted to use simulated non-radioactive wastes. At this larger scale the feed tank held 120 liters of waste and the filter unit was prototypic to the planned plant facility in pore size (0.1 micron), length (2.29 m), diameter (0.0127 m inside and 0.0159 m outside diameter), and being multi-tubed. The small-scale apparatus is convenient, easy to use, and can test both radioactive and non-radioactive wastes; therefore, there is a larger database than at the pilot scale. In fact, the small-scale data are very useful to compare actual waste to simulated waste filter performance to validate a simulant, but data availability does not mean they accurately represent full-scale performance. Results indicate that small-scale filter fluxes to be significantly higher that those at the pilot scale. In an attempt to study the difference in filter performance at the two scales an experiment was done that used exactly the same simultant which was created at the same time so that issues of composition and aging would not compromise the results. This paper will discuss those experimental results, as well as those from a computational fluid dynamics model to better understand the small-scale limitations.

scholarly journals Does size matter: scaling a composting experiment

2019 ◽  
pp. 365-373
Author(s):  
Mait Kriipsalu ◽  
Diauddin Nammari
Keyword(s):  
Laboratory Experiments ◽  
Volume Ratio ◽  
Cost Effective ◽  
Pilot Scale ◽  
Full Scale ◽  
Small Scale ◽  
Oily Sludge ◽  
Self Heating ◽  
Heat And Moisture ◽  
Size Matter

Composting has been considered one of the simplest and most cost-effective methods forbiotreatment of oily soil, sludge and sediments. By nature, composting is a large-scaleprocess, where certain mass is needed to retain heat and moisture. In order to optimizecomposting, especially with oily wastes, various experiments may be necessary. To representthe composting process in small scale, in particular the magnitude and duration of temperatureprofiles, adequate scaling is required. Small-scale composting experiments were conducted inorder to be able to analyze the scaling-up effects of laboratory and pilot-scale experimentsinto full-scale composting. Four naturally ventilated box reactors of different volumes: 2L,20L, 200L, and lO00L were used. The compost mixture consisted of oily sediments, sawdust,and peat. The temperature of all compost mixtures was recorded daily at the centre andsurface of each compost box, during a period of ten months. It was found, that the reactorswith a volume � 200L and a surface area to volume ratio (SA:V) 2': I 0: I, showed no differencebetween surface and centre temperature. The heat generated was lost to the surroundings at ahigher rate than could be sustained by the biomass. While the IO00L experiment with a SA:Vratio in the range of 6.0: I produced pronounced self heating. The results were in accordanceto the SA:V ratios and their relationship to heat generation and dissipation as shown inscientific literature. The results obtained, show that laboratory experiments with self-heatingreactors of SA:V ratio 2':I 0: I containing oily-sludge should not be used to simulate full scale,since the results are impossible to verify. In order to carry out reliable experiments simulatingfull scale composting processes in inexpensive self-heating reactors, it is suggested not toproceed with laboratory scale, but conduct properly insulated pilot-scale experiments withSA:V � 6.0:1.

Lab and pilot scale tests as tools for upgrading - comparison with full scale results

1998 ◽  
Vol 37 (9) ◽  
pp. 25-31 ◽  
Author(s):  
Åsa Malmqvist ◽  
Lars Gunnarsson ◽  
Christer Torstenon
Keyword(s):  
Biological Treatment ◽  
Low Cost ◽  
Treatment Plant ◽  
Paper Mill ◽  
Pilot Scale ◽  
Full Scale ◽  
Organic Load ◽  
Small Scale ◽  
Design Data ◽  
Biofilm Process

Parameters such as hydraulic retention time, organic load, maximum COD removal, sludge characteristics and optimal nutrient dosage can be determined by simulation in small scale models of the chosen process. Laboratory tests are the natural first step when considering upgrading, or designing a new, biological treatment plant. The potential for a biological treatment can be examined at a low cost and within a minimum of time, often through parallel testing of different treatment methods. Once a suitable process configuration has been found, lab scale tests may well be used for optimizing the process and obtaining design data, thus minimizing the need for more expensive tests in larger scale. The principal reason for a pilot plant test is the possibility to investigate natural variations in wastewater composition and the effect this will have on process stability. The use of laboratory and pilot scale tests is here illustrated by the work carried out prior to the upgrading of the treatment plant at Nyboholm paper mill. A description of the upgraded full scale installation consisting of both chemical treatment and a suspended-carrier biofilm process is included and a comparison between results from lab, pilot and full scale treatment is made.

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