Performance evaluation of a supercritical circulating fluidized bed boiler for power generation under flexible operation

2021 ◽  
pp. 095765092199396
Author(s):  
Matteo Bruzzone ◽  
Silvia Ravelli
Keyword(s):  
Power Generation ◽  
Fluidized Bed ◽  
High Performance ◽  
Circulating Fluidized Bed ◽  
Thermal Power ◽  
Rankine Cycle ◽  
Hard Coal ◽  
Cfb Boiler ◽  
Power Cycles ◽  
Commercial Code

It is well known that the Łagisza power plant in Poland is the world’s first supercritical circulating fluidized bed (CFB) boiler, whose commercial operation started on June 2009. It has attracted a great deal of interest and operational data are publicly available, therefore it has been chosen as the object of the present study aimed at assessing load and fuel flexibility of supercritical CFB plants. First, the thermal cycle was modelled, by means of the commercial code Thermoflex®, at nominal and part load conditions for validation purposes. After having verified the validity of the applied modelling and simulation tool, the advantage of having supercritical steam combined with CFB boiler over subcritical steam and pulverized coal (PC) boiler, respectively, was quantified in terms of electric efficiency. As a next step, the designed fuel, i.e. locally mined hard coal, was replaced with biomass: 100% biomass firing was taken into account in the case of subcritical CFB boiler whereas the maximum share of biomass with coal was set at 50% with supercritical CFB boiler, consistently with the guidelines provided by the world leading manufacturers of CFB units. A broad range of biomass types was tested to conceive mixtures of fuel capable of preserving quite high performance, despite the energy consumption in pretreatment. However, the overall efficiency penalty, due to biomass co-firing, was found to potentially undermine the benefit of supercritical steam conditions compared to conventional subcritical power cycles. Indeed, the use of low-quality biomass in thermal power generation based on steam Rankine cycle may frustrate efforts to push the steam cycle boundaries.

An Investigation Into the Operation of the Twin-Exit Loop-Seal of a Circulating Fluidized Bed Boiler in a Thermal Power Plant and Its Design Implication

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Prabir Basu ◽  
Munish Chandel ◽  
James Butler ◽  
Animesh Dutta
Keyword(s):  
Power Plant ◽  
Fluidized Bed ◽  
Thermal Power Plant ◽  
Circulating Fluidized Bed ◽  
Thermal Power ◽  
Scale Model ◽  
Circulation Rate ◽  
Cfb Boiler ◽  
Solids Circulation Rate ◽  
New Findings

Loop-seal is a critical component of a circulating fluidized bed (CFB) boiler, and yet very little information on its working or design is available in published literature. Among the limited available information, none is on twin-exit loop-seal though it is one of the most commonly used loop-seal in large commercial CFB boilers. To circulate larger amounts of solids, a twin-exit loop-seal provides larger solids flow sections. It receives solids from one standpipe but delivers it through two recycle chambers and two delivery pipes. The present research was conducted in a twin-exit loop-seal of a 3.2 MWth CFB boiler operating in a thermal power plant for cofiring purpose. Data obtained in this industrial unit were supplemented with those collected in a single-exit bench-scale loop-seal in the authors’ laboratory from the single-exit loop-seal in a 65 t/h CFB boiler and a scale model of a 30 MW CFB boiler. The effect of recycle chamber’s aeration on the solids circulation rate was studied for several particle sizes. Results suggest that the total solids circulation rate does not increase proportionately with the increase in loop-seal discharge area provided by the twin-exit loop-seals. The linear horizontal velocities of solids and the minimum aeration in the recycle chambers are comparable to those measured in a single-exit loop-seal. The implication of these new findings on the design procedure of loop-seals is discussed.

scholarly journals On the Perspective of Transfer of Omsk Thermal Power Plants to Combustion of Fired Coals

2021 ◽  
pp. 118-129
Author(s):  
Ainur A. Kuandykova ◽  
Vitaly M. Lebedev
Keyword(s):  
Fluidized Bed ◽  
Thermal Energy ◽  
Power Plants ◽  
Fossil Fuel ◽  
Circulating Fluidized Bed ◽  
Thermal Power ◽  
Energy System ◽  
Thermal Power Plants ◽  
Cfb Boiler ◽  
Solid Fossil Fuel

The existing issues during the combustion of Kazakh coal from the Ekibastuz basin in the Omsk energy system are noted. The environmental problems of coal generation in Omsk are outlined. The possibility of transferring the Omsk coal-fired thermal power plants to the combustion of domestic coals is considered. The options for increasing the efficiency of using solid fossil fuel in the production of electric and thermal energy are given. The existing problem of storing ash and slag wastes obtained by burning high-ash Ekibastuz coals is noted. The transfer of the Omsk CHPPs to the combustion of brown coal from the Kansk-Achinsky deposit, provided that highly effective environmentally friendly technologies are used It is noted that the technology of combustion of fuels in a circulating fluidized bed (CFB) has been industrially developed and implemented in power boilers. The results of operation of the first in Russia CFB boiler of unit No. 9 with a capacity of 330 MW at the Novocherkasskaya SDPP are presented

Application of Supercritical Fluids in Thermal- and Nuclear-Power Engineering

2021 ◽  
pp. 601-658
Author(s):  
Igor L. Pioro
Keyword(s):  
Heat Transfer ◽  
Carbon Dioxide ◽  
Supercritical Fluids ◽  
Nuclear Power ◽  
Power Plants ◽  
Thermal Power ◽  
Rankine Cycle ◽  
Working Fluid ◽  
Thermal Power Plants ◽  
Power Cycles

Supercritical Fluids (SCFs) have unique thermophyscial properties and heat-transfer characteristics, which make them very attractive for use in power industry. In this chapter, specifics of thermophysical properties and heat transfer of SCFs such as water, carbon dioxide, and helium are considered and discussed. Also, particularities of heat transfer at Supercritical Pressures (SCPs) are presented, and the most accurate heat-transfer correlations are listed. Supercritical Water (SCW) is widely used as the working fluid in the SCP Rankine “steam”-turbine cycle in fossil-fuel thermal power plants. This increase in thermal efficiency is possible by application of high-temperature reactors and power cycles. Currently, six concepts of Generation-IV reactors are being developed, with coolant outlet temperatures of 500°C~1000°C. SCFs will be used as coolants (helium in GFRs and VHTRs, and SCW in SCWRs) and/or working fluids in power cycles (helium, mixture of nitrogen (80%) and helium (20%), nitrogen and carbon dioxide in Brayton gas-turbine cycles, and SCW/“steam” in Rankine cycle).

scholarly journals Feasibility Study of Using Carbide Slag as In-Bed Desulfurizer in Circulating Fluidized Bed Boiler

2019 ◽  
Vol 9 (21) ◽  
pp. 4517 ◽  
Author(s):  
Zhong Huang ◽  
Jimiao Long ◽  
Lei Deng ◽  
Defu Che
Keyword(s):  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Separation Efficiency ◽  
Molar Fraction ◽  
So2 Emissions ◽  
Cfb Boiler ◽  
Carbide Slag ◽  
Desulfurization Efficiency ◽  
Sintering Resistance ◽  
Pilot Tests

Carbide slag is a waste residue during the production of acetylene. Due to its high content of Ca(OH)2, carbide slag becomes a potential alternative to limestone as the in-bed desulfurizer of circulating fluidized bed (CFB) boilers. In this study, the calcination and sulfation characteristics of carbide slag were investigated by three different facilities, thermogravimetric analyzer (TGA), 1 MWth pilot CFB boiler, and 690 t·h−1 CFB boiler. Pore structures and sulfation behaviors of carbide slag and limestone were investigated for the sake of comparison. The results showed that carbide slag has a lower calcination temperature than limestone. Its calcined product has a better pore structure and desulfurization activity. The carbide slag exhibited a higher desulfurization efficiency than the limestone in the pilot tests. The SO2 emission concentration showed a downward trend with the increase of molar fraction of carbide slag in the desulfurizer. Meanwhile, carbide slag had a better sintering-resistance property, which makes it possible to effectively reduce SO2 emissions even at high combustion temperatures (>910 °C). While the field test results were similar to that of the pilot tests, the desulfurization efficiency of carbide slag with the same Ca/S mole ratio was higher than that of limestone. The fine size of carbide slag particles and the lower separation efficiency of the cyclone on the 690 t·h−1 boiler left the carbide slag with insufficient residence time in the furnace. Therefore, it is necessary to ensure a high separation efficiency of the cyclone if the carbide slag is used as an alternative desulfurizer in furnace.

Analysis of Solar-Thermal Power Cycles for Distributed Power Generation

2009 ◽  
Author(s):  
Suzanne E. Price ◽  
J. Rhett Mayor
Keyword(s):  
Power Generation ◽  
Thermal Power ◽  
Solar Thermal ◽  
Efficiency Ratio ◽  
Pinch Point ◽  
Kalina Cycle ◽  
Distributed Power ◽  
Power Cycles ◽  
Solar Thermal Power ◽  
Distributed Power Generation

In this study, the thermoeconometric feasibility of a 12.5 kW solar thermal power system is discussed. A previous study by these authors examined five potential 12.5kW solar thermal cycles and preliminary thermoeconometric analyses based on the collector area. The current study expands to six potential power cycles, including the five from the previous study, the Rankine, R123 Organic Rankine, toluene Organic Rankine, ethylbenzene organic Rankine, and the Kalina cycle, with the addition of the Maloney-Robertson cycle as well as detailed cost analysis for the components associated with each cycle. A detailed first law thermodynamic analysis for the Maloney-Robertson and Kalina cycles is presented. Likewise, the pinch point analysis is used for the inclusion of the sink and source stream as well as a developed heat exchanger model. The thermoeconometric study includes cost-per-component estimates for all of the components in the cycles; thus, increased component cost is taken into account for the ammonia-water cycles. The findings from this study show that R123 is the only cycle that operates with a source temperature below 225°C within the cycle applied operating constraints for meso-scale distributed power generation.. When higher temperatures are achieved, the Kalina cycle has the highest thermal efficiency but also the highest cost-to-efficiency ratio. Therefore, the thermoeconometrics study shows that the toluene and ethylbenzene ORCs have the lowest cost-to-efficiency ratio when source temperatures reach 225°C to 350°C even though they do not have the highest cycle efficiencies.

Photocatalytic Degradation of Acid Red G by Bismuth Titanate in Three-phase Fluidized Bed Photoreactor

2011 ◽  
Vol 14 (1) ◽  
Author(s):  
Hong Liu ◽  
Ho Kyong Shon ◽  
Yousef Okour ◽  
Weikun Song ◽  
Saravanamuthu Vigneswaran
Keyword(s):  
Photocatalytic Degradation ◽  
Fluidized Bed ◽  
High Performance ◽  
Bismuth Titanate ◽  
Circulating Fluidized Bed ◽  
Molar Ratio ◽  
Optimum Operating ◽  
Hydrothermal Temperature ◽  
Three Phase ◽  
Acid Red G

AbstractThe objectives of this study were to prepare a high-performance bismuth titanate photocatalyst and to develop a novel photocatalytic reactor with three-phase internal circulating fluidized bed photoreactor (TPICFBP). Bismuth titanate photocatalyst was hydrothermally prepared under optimum operating parameters such as hydrothermal temperature, reaction time and molar ratio of Bi to Ti. The photocatalytic activity of bismuth titanate using TPICFBP was evaluated for the photocatalytic degradation of Acid Red G (ARG). The photodegradation of ARG over Bi

Performance and Operation Analysis of a Quadra Sectors Rotary Airheater Adopted by CFB Boiler

2014 ◽  
Vol 1070-1072 ◽  
pp. 1764-1768
Author(s):  
Zhan Guo Li ◽  
Zhen Ning Zhao ◽  
Zhi Qiang Wen
Keyword(s):  
Thermal Properties ◽  
Control System ◽  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Air Leakage ◽  
Circulating Fluidized Bed Boiler ◽  
Cfb Boiler ◽  
Operation Analysis ◽  
Operation Modes ◽  
Leakage Control

Based on the aspects of thermal properties, resistance properties, air Leakage Control and boiler output adaptability, the operation modes and their impact of a quad-sector rotary airheater adopted by a 330MWe circulating fluidized bed boiler are analyzed by tests. And the operation methods of Leakage Control System are concluded. In order to improve the reliability of rotary airheater with main and auxiliary motors, recommendations for improvement are extended.

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