Engineering Commons^™

Effect Of Temperature Field On The Coal Devolatilization In A Millisecond Downer Reactor, Binhang Yan, Li Zhang, Yong Jin, Yi Cheng

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

A comprehensive CFD-DPM model was established to describe coal pyrolysis in millisecond downer reactors under high temperatures. The model predictions revealed the fact that the reactor performance is dominated by the design of the temperature field to guarantee fast, sufficient heating of coal particles in milliseconds

Experimental Study On Reforming Activity And Oxygen Transfer Of Fe- Olivine In A Dual Circulating Fluidized Bed System, Stefan Koppatz, Tobias Pröll, Christoph Pfeifer, Hermann Hofbauer

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

Fe-olivine was investigated in a dual circulating fluidised bed reactor system with focus on hydrocarbon reforming activity and effects of oxygen transfer. H2, CO2, CH4 and 1-methylnaphthalene were fed as a surrogate gas mixture to the reforming part. Oxygen transport was developed by solids circulation. Tar decomposition was marginally affected by partial oxidation. The overall degree of tar decomposition was found to be in the range of 70 to 80%.

Effects Of Secondary Air Injection Upon The Fluidization Characteristics Of The Lower Stage In A Two-Stage, Variable-Area Fluidized Bed Riser, Eric K. Johnson, Steven L. Rowan

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

A transparent scale model of a two-stage fluidized bed coal dryer with a small diameter lower stage and a large diameter upper stage, separated by a conical transition zone with secondary air injection ports, has been constructed to study the effects of secondary air injection upon the fluidization characteristics of the lower riser stage. The superficial velocity of the lower stage of the riser was held constant within the turbulent fluidization regime while the superficial gas velocity in the upper riser stage was varied by changing the volumetric flow rates of air introduced between the upper and lower riser stages. …

Oxy-Combustion Of Different Coals In A Circulating Fluidized Bed, Adam Luckos, Monika Kosowska-Golachowska, Konrad Klos, Tomasz Musial

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

Combustion of three Polish and one South African bituminous coal particles in air versus O2/CO2 mixtures with oxygen concentrations in the range from 21% to 60% vol. was conducted at temperature of 850°C in a 12 kW bench-scale CFB combustor. Combustion in air was proceeded at ~50˚C higher centre temperatures and was slightly shorter in time compared to combustion in O2/CO2 mixture with 21% vol. O2. Larger heat capacity of CO2 compared to that of N2 also retards the ignition of volatiles in O2/CO2 mixtures with 21% O2. However, when the concentration of oxygen in O2/CO2 mixtures is larger than …

Comparison Between Measurements And Numerical Simulation Of Particle Flow And Combustion A The Cfbc Plant Duisburg, M. Weng, J Plackmeyer

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

The article presents the 3-dimensional numerical simulation of combustion and particle flow as an efficient engineering tool for analysis and optimization of fluidized bed combustion chambers. The comparison with measurements that were carried out within a European Research Project and with operational experience shows very good agreement and provides recommendations for future optimization.

Elutriation From Fluidized Beds: Comparison Between Experimental Measurements And 3d Simulation Results, Renaud Ansart, Herve Neau, Olivier Simonin, Philippe Accart, Alain De Ryck

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

This paper presents comparisons between experimental measurements and unsteady threedimensional numerical simulations performed by an unstructured parallelized CFD multiphase flow code of elutriation and transport of mono-dispersed glass beads type B and A/B in a fluidized bed. These comparisons show a satisfactory agreement between experimental measurements and numerical predictions. The numerical results also show a strong dependence on the mesh size, especially for fine particles. A model accounting for influences of mesoscales structures on overall bed hydrodynamics, which are not resolved by coarse mesh simulations, is applied. Results obtained with the model show improvements for the dense fluidized bed and …

Hydrodynamics Of A Cluster Descending At The Wall Of A Cfb Riser - Numerical Study, John R. Grace, Subhashini Vashisth

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

The incompressible hydrodynamics of a single parabolic cluster descending at the wall of a CFB riser was numerically simulated using a 2-D Eulerian-Granular model and a segregated time-dependent unsteady solver. Numerical predictions of the velocity of descent and the evolution of cluster shape are in reasonable agreement with experimental results available in the literature.

High Sulfur Lignite Fired Large Cfb Boilers-Design And Operating Experience, M. Lakshminarasimhan, B. Ravikumar, A. Lawrence, M. Muthukrishnan

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

One of the measures of the prosperity of a nation is per capita consumption of electricity. In developing countries like India the gap between supply and demand is strongly increasing. The demand for all forms of energy is expected to increase substantially in the foreseeable future and is forecasted to double by 2020. Although coal would continue to be a major energy source in India due to its availability, lignite is fast emerging as an alternate source of fuel for electricity generation. In India the total lignite potential is 4177 million tonnes. The varieties found in India (Gujarat & Rajasthan …

Research On Heat Transfer Inside The Furnace Of Large Scale Cfb Boilers, Ruiqing Zhang, Hairui Yang, Hai Zhang, Qing Liu, Junfu Lu, Yuxin Wu

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

Field tests in one unit of 135MWe and two units of 300MWe commercial Circulating Fluidized bed (CFB) boilers (A&B) with different structures were carried out. The influence of operating conditions on the thermal boundary layer, local heat transfer coefficient and peripheral distribution of heat transfer coefficient were studied. It was found that, in the 135MWe and 300MWe-A CFB furnace, the thickness of the thermal boundary layer was almost constant, about 100mm, and independent of the height above the distributor and the boiler load. The local heat transfer coefficient increased with increasing load as well as the coal feeding rate and …

Co-Gasification Of Biomass And Coal In An 8mw Dual Fluidized Bed Steam Gasifier, Christoph Pfeifer, Isabella Aigner, Hermann Hofbauer

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

Gasification of biomass is an attractive technology for combined heat and power production. Co-gasification of biomass and coal was tested in an 8 MW dual fluidized bed steam gasifier with coal ratios up to 22% on an energy basis. Hydrogen levels in the producer gas increased with the addition of coal as well as ammonia, hydrogen sulfide and tars. Addition of coal to the system stabilized the process and improved gas quality.

Operating Experience And Latest Developments Of Alstom Power's 300 Mwe Class Cfb Boilers, Iqbal Abdulally, Bruce Wilhelm, Christian Enault, Pierre Gauville

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

Fuel flexibility combined with low emissions, particularly with high sulphur fuels, are the key drivers for installing a Circulating Fluidised Bed (CFB) Boiler. Taking into account the global drive for more efficient and clean combustion, and the development of CFB combustion and emission reduction technologies accordingly, worldwide applications for CFB Boilers are increasing. Accordingly, Alstom Power continues the evolutionary development of its CFB Boiler portfolio, based on the experience gained with operating units. This paper focuses on Alstom Power’s 300 MWe Class CFB Boiler products. East Kentucky Power Cooperative's (EKPC) Spurlock unit 4 is one of the large Alstom’s 300 …

Coal And Biomass Co-Gasification In A Circulating Fluidized Bed Reactor, Andrzej Czaplicki, Marek Sciazko

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

Co-gasification tests of subbituminous coal with biomass were performed. A rape straw blended with coal was used in a mass ratios of coal/biomass of 25%, 50% and 75%. The gasification process was conducted in a circulating fluid bed reactor at atmospheric pressure with air and steam addition was applied to the reaction. The addition of biomass to coal resulted in a higher conversion to gas and increased the gas calorific value due to higher content of carbon oxide

Design And Operation Of Biomass Circulating Fluidized Bed Boiler With High Steam Parameter, Li Shiyuan, Lu Qinggang, Teng Haipeng, Shaolin Bao, Dongyu Wang

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

Two circulating fluidized bed(CFB) boilers with capacity of 12 MWe and 25 MWe, respectively, with biomass as fuel, adopting the basic technology independently developed by Institute of Engineering Thermophysics (IET), Chinese Academy of Sciences, have been in commercial operation since March 2010 in China. This paper focuses on the design principles, the design specifications and operating results of the two CFB boilers.

Commissioning Of A 0.8 Mwth Cfbc For Oxy-Fuel Combustion, L. Jia, D. Mccalden, Y. Tan, Y. Wu, I. He, R. Symmonds, E.J. Anthony

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

Oxy-fuel fluidized bed combustion (FBC) is a new technology being developed for power production from carbonaceous fuels while producing a nearly pure steam of CO2 ready for sequestration or storage. Unlike oxy-fuel pulverized fuel combustion technology, oxy-fuel FBC offers the opportunity to use poor quality coals, hydrocarbon residues and a range of other materials including biomass. In Canada, pitches, tars and bottoms, in particular, are available in large quantities in western Canada, and this technology offers an opportunity to deal with many of these waste feedstocks in an environmentally benign manner. In addition, oxy-fuel circulating FBC (CFBC) can be fired …

A Web-Oriented Multi-Layer Model To Interact With Theatrical Performances, A Baratè, G. Haus, L A. Ludovico, Davide Andrea Mauro

Computer Sciences and Electrical Engineering Faculty Research

This paper presents an innovative approach to online fruition

of theater performances. Web applications like traditional viewers are

already available for the wide audience of Internet users. Our proposal

aims at adding both interactivity and multi-layer fruition, and a way

to manipulate and create new media. The premise to reach these goals

is digitizing a number of heterogeneous materials in order to describe a

single performance comprehensively, e.g. different video and audio-takes

from different perspectives, and a number of related materials such as

scripts, fashion plates, playbills, etc. The format we adopt to encode

such information is based on the …

Particle To Gas Heat Transfer In A Circulating Fluidized Bed Riser, Yassir Makkawi

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

The main objective of this study was to measure the heat transfer from particle to gas in a dilute CFB riser (  0.8 ) and to derive a predictive equation for the local particle-gas heat transfer coefficient. This coefficient was found to be a strong function of the particle velocity, concentration and length of the heat transfer section. Accordingly, a new correlation in terms of these parameters is proposed.

Study Of Recarbonation In Circulating Fluidized Bed Combustion, Marko Palonen, Irina Hyyatiäinen, Anna Mahlamäki, Mikko Varonen

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

Oxy-fuel circulating fluidized bed combustion (CFBC) can use calcium based sorbents, primarily limestone, for the in-situ capture of much of the sulfur dioxide in the fuel. Under oxy-fuel CFBC conditions, the CO2 content is usually high, and at high combustor temperatures sulfur capture can occur in two steps, calcination and then sulfation. The typical Ca utilization ratio in oxy-fuel CFBCs is less than half. When temperature is below the calcination temperature while remaining exposed to a high CO2 environment, recarbonation of unused CaO may occur. This reaction between calcium oxide and carbon dioxide has the potential to create serious operational …

Uop Fcc Innovations Developed Using Sophisticated Engineering Tools, Lisa Wolschlag, Keith Couch

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

Fluid Catalytic Cracking (FCC) technology has been a part of the petroleum industry since the 1940’s. Yet, despite being a very mature technology, continued development is vital, especially as many refiners move their FCC operations from fuels production to higher value products. Advanced diagnostic and design tools are accelerating process developments and have resulted in several innovations. Through the development and commercialization of world record scale FCC units, technical discoveries have emerged, which have provided opportunities for improvements across all units, independent of size. Through the development and use of sophisticated engineering tools such as Computational Fluid Dynamic (CFD) modeling, …

Ecosystem Management Of The Missouri River From Gavins Point Dam To Ponca State Park, Nebraska, Robert S. Nebel

United States Army Corps of Engineers, Omaha District

•Authorized by a 1978 amendment to the National Parks and Recreation Act (PL 95- 625) which amended the Wild and Scenic Rivers Act of 1968 (PL 90-542)

• Corps is authorized to construct recreational development, bank stabilization, and other recreational river features as necessary to support the values for which the river was designated

• Life-of-project funding ceiling of $21 million; approximately $3.2 million spent to date

• The Corps and National Park Service signed a 1980 Cooperative Agreement outlining each agency's responsibilities

• The General Management Plan has recently been updated (1999) with an environmental emphasis

Omaha District Area Of Operations (Map)

United States Army Corps of Engineers, Omaha District

Universities

Engineering & ROTC

ROTC

United States Bases

AIR FORCE

Legend

ARMY

BOR Dams

Real Estate Field Offices

Regulatory Offices

State Capital

Area Offices

Resident Offices

Operations Project Offices

District Headquarters

River

Lake

Civil Boundary

Military Boundary

Regulatory Boundary

State

National Park

Sovereign Tribal Nations

State

Province

Investigation On The Hydrodynamic Properties In The External Loop Of Circulating Fluidized Bed With A Loop Seal, Hairui Yang, Xuan Yao, Tao Wang, Hai Zhang, Qing Liu, Junfu Lv, Guangxi Yue

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

The pressure balance and mass balance are influenced by the characteristics of different components in the loop of a circulating fluidized bed (CFB). Experiments were conducted in a 4.3 m high cold laboratory CFB test rig with a loop seal. With a fixed bed inventory and superficial gas velocity, the pressure drop of the loop seal decreased with increasing aeration, thus causing an increase in the solid circulation flux (Gs). Correspondingly, the pressure drop in the riser became higher with increasing Gs; the pressure drop of the cyclone had a non-linear relationship with Gs, and the transition point was determined …

A Generalized Flow Regime Diagram For Fluid-Solid Vertical Transport, Xiaotao T. Bi

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

An ideal generalized flow regime diagram was proposed for fluid-solids vertical transport systems with no bottom and top restrictions. Such an ideal flow regime diagram was further extended to shed light onto the understanding of the flow regimes and instabilities encountered in bottom- restricted bubbling and circulating fluidized bed systems.

High-Flux Triple Bed Circulating Fluidized Bed (Tbcfb) Gasifier For Exergy Recuperative Igcc/Igfc, Chihiro Fushimi, Guoqing Guan, Masanori Ishizuka, Yu Nakamura, Atsushi Tsutsumi, Yoshizo Suzuki, Eldin Wee, Yong Cheng, Chi-Hwa Wang

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

The flow behavior of silica sand, of average particle size 128 μm, was investigated using a large-scale triple-bed combined circulating fluidized bed (TBCFB) cold model, which was composed of a 0.1 m I.D. ×16.6 m tall riser, a solids distributor, a 0.1m I.D. × 6.5 m long downer, a gas-solids separator, a 0.75 m × 0.27 m × 3.4 m bubbling fluidized bed and a 0.158 m I.D. × 5.0 m tall gas-sealing bed (GSB) with a high solids mass flux. The main focus of this study is to determine effect of riser secondary air injection on solids mass flux …

Process Decoupling Of Plasma Enhanced Synthesis Of Chlorinated Polyvinyl Chloride (Cpvc) Particles In A Circulating Fluidized Bed, Wei Lu, Teng Cao, Yong Jin, Yi Cheng

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

Plasma enhanced synthesis of CPVC particles in a gas-solid plasma circulating fluidized bed reactor (PCFBR) is proposed as a novel CPVC synthesizing method. The chlorination process is decoupled into a fast initiation step in a plasma riser and a slow chlorination process in the accompanying bed. The CPVC product has good properties in terms of chlorine content and microstructure.

Flow Rate Of Solids In L-Valves, Duvvuri Subbarao

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

Movement of solids in a L-valve by fluid drag due to external aeration is opposed by frictional resistance at the wall/non-moving solids. Model equations developed for the threshold aeration rate and solids flow rate as a function of aeration rate compare well with the literature data.

Cold Model Investigations Of A High Temperature Looping Process In A Dual Circulating Fluidized Bed System, Ajay R. Bidwe, Miguel A.M Dominguez, Craig Hawthorne, Heiko Dieter, Alexander Charitos, Anjia Schuster, Güenter Scheffknecht

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

The Calcium Looping process is a promising post-combustion CO2 capture technology. A 200 kWth Dual Circulating Fluidized Bed has been built at IFK, University of Stuttgart. Tests were carried out on a hydrodynamically scaled cold model. Operating parameters have been varied, while the suitability of the 200 kWth design has been proven

Bio-Gasoline From Jatropha Oil: New Applications For The Fcc- Process, Alexander Weinert, Alexander Reichhold, Peter Bielansky, Christoph Schönberger, Bettina Schumi

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

Jatropha curcas L. is a very drought-resistant plant, and jatropha oil can be ex-tracted from its seeds. Whilst not suitable for human consumption, we found that it is a promising feedstock for producing (bio)-gasoline. The oil was cracked in an inter-nally circulating FCC-reactor using a Grace Davison Ultima® catalyst. The total con-version was around 65%, with ca. 40% gasoline and ca. 25% crack gas (exact num-bers varied with reactor temperature). The gasoline has a RON > 95 and oxy-gen < 0.3% m. The crack-gas consisted of ca. 35% propylene, ca. 13% 1-butene and ca. 6% ethylene.

Effects Of Particle Properties On Cluster Characteristics In A 2-D Cfb Riser, Jesse Zhu, Jing Xu

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

The characteristic of particle clusters was studied in a 2-D circulating fluidized bed riser by using a digital image system and optical fiber probes. A new parameter, cluster number fraction, was proposed to characterize the clusters. The results indicated the smaller and lighter particles have higher potential to aggregate, while the effects of particle sphericity were less significant than those of particle density and size.

Hydrodynamics Of A Loop-Seal Operated In A Circulating Fluidized Bed: Influence Of The Operating Conditions On Gas And Solid Flow Patterns, Roberto Solimene, Riccardo Chirone, Piero Bareschino, Piero Salatino

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

Hydrodynamic features of a loop-seal operated as solids re-injection device in a labscale cold CFB apparatus are studied. Gas flow patterns are characterized by means of gas tracing experiments with continuous injection of CO2 in the loop-seal chambers. Solids flow patterns are characterized by impulsive injection of dyecoloured particles into the supply chamber, followed by particle tracking.

Manufacture Of Granular Polysilicon From Trichlorosilane In An Internally Circulating Fluidized Bed Reactor, Chenjing Wang, Tiefeng Wang, Zhanwen Wang

10th International Conference on Circulating Fluidized Beds and Fluidization Technology - CFB-10

A lab scale internally circulating fluidized bed (ICFB) with a centrally located draft tube was designed to make polysilicon from trichlorosilane. Experimental results and evaluations showed that particle circulation could carry enough heat for reaction and effectively decrease wall deposition. Well grown granular polysilicon was obtained in a stable fluidization state and particle circulation rate.