Elements of a Successful Waste-to-Energy Boiler Upgrade

2009 ◽  
Author(s):  
Samit J. Pethe ◽  
Chris Dayton ◽  
Marcel D. Berz ◽  
Tim Peterson
Keyword(s):  
Waste To Energy ◽  
Cfd Modeling ◽  
Steam Turbines ◽  
Steam Generation ◽  
Operator Training ◽  
Refuse Derived Fuel ◽  
Energy Plant ◽  
History Of ◽  
Emission Limits ◽  
Combustible Gases

Great River Energy operates a waste-to-energy plant in Elk River, Minnesota. The plant burns 850 tons per day of refuse derived fuel (RDF) in three boilers, and its three steam turbines can produce 32 MW of electricity. In the largest of the three units, the No. 3 Boiler, steam generation was restricted by carbon monoxide (CO) and nitrogen oxides (NOx) emission limits. The plant had an interest in improving the combustion performance of the unit, thereby allowing higher average RDF firing rates while staying within emissions compliance. The project was initiated by an engineering site visit and evaluation. The boiler had a history of unstable burning on the stoker grate, which required periodic natural gas co-firing to reduce CO levels. As an outcome to the evaluation, it was decided to install a new overfire air (OFA) system to improve burnout of combustible gases above the grate. Current and new OFA arrangements were evaluated via Computational Fluid Dynamics (CFD) modeling. The results illustrated the limitations of the original OFA system (comprised of multiple rows of small OFA ports on the front and rear furnace walls), which generated inadequate mixing of air and combustible gases in the middle of the boiler. The modeling illustrated the advantages of large and fewer OFA nozzles placed on the side walls in an interlaced pattern, a configuration that has given excellent performance on over 45 biomass-fired boilers of similar design upgraded by Jansen Combustion and Boiler Technologies, Inc. (JANSEN). Installation of the new OFA system was completed in April of 2008. Subsequent testing of the No. 3 Boiler showed that it could reliably meet the state emission levels for CO and NOx (200 ppm and 250 ppm, respectively, corrected to 7% dry flue gas oxygen) while generating 24% more steam than a representative five month period prior to the upgrade. This paper describes the elements that led to a successful project, including: data collection, engineering analyses, CFD modeling, system design, equipment supply, installation, operator training, and startup assistance.

Carbon Monoxide Emission Improvements From Combustion System Upgrades at the Wheelabrator Portsmouth Refuse Derived Fuel Plant

2012 ◽  
Author(s):  
Samit J. Pethe ◽  
Michael L. Britt ◽  
Scott A. Morrison
Keyword(s):  
Carbon Monoxide ◽  
Electrical Power ◽  
High Elevation ◽  
Waste To Energy ◽  
Cfd Modeling ◽  
Combustion System ◽  
Steam Generation ◽  
Design Concepts ◽  
Refuse Derived Fuel ◽  
Boiler Operation

Wheelabrator Technologies Inc. (WTI) operates a waste-to-energy facility in Portsmouth, Virginia. At full capacity, a total of 2,000 tons/day of refuse derived fuel (RDF) can be fired in four identical boilers to generate a total of 600,000 lb/hr of steam and 60 MW of electricity. The boilers were originally designed to co-fire RDF and coal; however, coal burning capability was removed a few years after commissioning. The plant provides all of the process/heating steam and the majority of the electrical power to the nearby Norfolk Naval Shipyard. Historically, the boilers had not been able to reliably achieve carbon monoxide (CO) emissions compliance. CO emissions experienced during normal boiler operation would be more than twice the mandated emission limit. WTI’s goal was to improve the boilers’ CO emissions performance while achieving sustained boiler operation at higher steam generation and RDF firing rates. WTI contracted Jansen Combustion and Boiler Technologies, Inc. (JANSEN) to evaluate the operation of the boilers, to assess the overall feasibility of meeting WTI’s goals, and to develop design concepts to overcome boiler limitations. The project was initiated by an engineering site visit where boiler operating data was collected and evaluated to develop a baseline of boiler operation. Current and new combustion system arrangements were evaluated with Computational Fluid Dynamics (CFD) modeling. The results confirmed that the root cause of the poor CO emissions performance was the inadequate penetration and mixing of the original overfire air (OFA) system (comprised of multiple rows of small ports on the front and rear furnace walls). CFD modeling also showed increased CO emissions to result from non-uniform RDF delivery profiles generated by the original fuel distributors that were installed at a high elevation over the grate. Modeling of the furnace with larger and fewer OFA nozzles placed on the side walls in an interlaced pattern, and the installation of “new-style” RDF distributors at a lower elevation where the boiler’s original coal distributors formerly were located was shown to significantly improve CO burnout. From December 2010 to May 2011, the new combustion systems were installed on all four boilers. Subsequent testing has shown that CO levels have been lowered by more than 70% and boiler availability has been significantly improved. Nitrogen oxides (NOx) emissions, although slightly higher following the upgrade, are still within the NOx compliance limit. This paper describes the process that led to a successful project, including: data collection and analyses, CFD modeling, equipment design and supply, operator training, and start-up assistance.

Two Phase Flow CFD Modeling to Enhance Steam Turbines LP Stages Performance Predictability: Comparison With Data and Correlations

2020 ◽  
Author(s):  
Nicola Maceli ◽  
Lorenzo Arcangeli ◽  
Andrea Arnone
Keyword(s):  
Power Generation ◽  
Power Plants ◽  
Raw Materials ◽  
Sustainable Use ◽  
Waste To Energy ◽  
Cfd Modeling ◽  
Reliable Estimate ◽  
Primary Role ◽  
Steam Turbines ◽  
Two Phase

Abstract The whole energy market, from production plants to end-users, is marked by a strong impulse towards a sustainable use of raw materials and resources, and a reduction of its carbon foot-print. Increasing the split of energy produced with renewables, improving the efficiency of the power plants and reducing the waste of energy appear to be mandatory steps to reach the goal of sustainability. The steam turbines are present in the power generation market with different roles: they are used in fossil, combined cycles, geothermal and concentrated solar plants, but also in waste-to-energy and heat recovery applications. Therefore, they still play a primary role in the energy production market. There are many chances for efficiency improvement in steam turbines, and from a rational point of view, it is important to consider that the LP section contributes to the overall power delivered by the turbine typically by around 40% in industrial power generation. Therefore, the industry is more than ever interested in developing methodologies capable of providing a reliable estimate of the LP stages efficiency, while reducing development costs and time. This paper presents the results obtained using a CFD commercial code with a set of user defined subroutines to model the effects of non-equilibrium steam evolution, droplets nucleation and growth. The numerical results have been compared to well-known test cases available in literature, to show the effects of different modeling hypotheses. The paper then focuses on a test case relevant to a cascade configuration, to show the code capability in terms of bladerow efficiency prediction. Finally, a comprehensive view of the obtained results is done through comparison with existing correlations.

Superheater Life With Stainless, Inconel, and Carbon Steel Alloys at the Maine Energy Recovery Company

2004 ◽  
Author(s):  
Ken Robbins ◽  
Ken Huard ◽  
John King
Keyword(s):  
Energy Recovery ◽  
Waste To Energy ◽  
Production Operation ◽  
Gas Temperature ◽  
Turbine Generator ◽  
Design Changes ◽  
Energy Facility ◽  
Refuse Derived Fuel ◽  
Commercial Operation ◽  
History Of

The Maine Energy Recovery Company is a refuse derived fuel (RDF) waste to energy facility that began commercial operation in 1987. The facility consists of an RDF production operation, two B&W boilers which produce 210,000 lb/hr of steam at 650 psig/750F with a design Furnace Exit Gas Temperature of 1700 F, and a 22 MW steam turbine generator. Since startup, the facility has suffered fireside erosion/corrosion of the waterwalls, superheater, and generator bank hot side sections. Through the years, Maine Energy has made various operational and design changes in order to improve combustion and overall boiler availability. While combustion has improved as evidenced by improved emissions, reduced supplemental fuel usage, and lower ash production, superheater availability has suffered. At the same time reliability of the waterwall and generating bank components have improved. This paper will present a history of Maine Energy’s efforts to improve its superheater availability including a summary of the tube wastage rates for various superheater alloys, as well as Maine Energy’s plans for its superheaters.

scholarly journals Numerical Simulation of Refuse-Derived Fuel ThermoChemical Conversion in a Waste-to-Energy Plant

2017 ◽  
Author(s):  
Michela Costa ◽  
Christian Curcio ◽  
Daniele Piazzullo ◽  
Vittorio Rocco ◽  
Raffaele Tuccillo
Keyword(s):  
Numerical Simulation ◽  
Waste To Energy ◽  
Thermochemical Conversion ◽  
Refuse Derived Fuel ◽  
Energy Plant

scholarly journals Performance of an amine-based CO2 capture pilot plant at the Fortum Oslo Varme Waste to Energy plant in Oslo, Norway

2021 ◽  
Vol 106 ◽  
pp. 103242
Author(s):  
Johan Fagerlund ◽  
Ron Zevenhoven ◽  
Jørgen Thomassen ◽  
Marius Tednes ◽  
Farhang Abdollahi ◽  
...  
Keyword(s):  
Co2 Capture ◽  
Pilot Plant ◽  
Waste To Energy ◽  
Energy Plant

Integrated Management of Solid Wastes for New York City

2002 ◽  
Author(s):  
Nickolas J. Themelis
Keyword(s):  
New York ◽  
New York City ◽  
York City ◽  
Power Plants ◽  
Integrated Management ◽  
Solid Wastes ◽  
Waste To Energy ◽  
Advanced Technology ◽  
Municipal Solid Wastes ◽  
Energy Plant

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.

Corrosion of superheater materials in a waste-to-energy plant

2013 ◽  
Vol 105 ◽  
pp. 106-112 ◽  
Author(s):  
Peter Viklund ◽  
Anders Hjörnhede ◽  
Pamela Henderson ◽  
Annika Stålenheim ◽  
Rachel Pettersson
Keyword(s):  
Waste To Energy ◽  
Energy Plant
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