Babcock & Wilcox Enterprises Inc. (NYSE: BW) also known as Babcock & Wilcox (B&W), originally The Babcock & Wilcox Company, is an American renewable, environmental and thermal energy technologies and service provider that is active and has operations in many international markets across the globe with its headquarters in Akron, Ohio USA. Historically, the company is best known for their steam boilers.
Abstract This work evaluates an iron-based chemical looping oxidation process for CO2 isolation from refinery residues, petroleum coke, and off-gases, characterizing capture rate, product purity, and energy load against post-combustion amine and oxy-fuel benchmarks. Bench and pilot scale chemical looping units were operated on natural gas, syngas, tail gas, coal, and refuse-derive fuel (RDF) using an iron-based oxygen carrier, with performance benchmarked on a steam-and-hydrogen coproduction basis. Capture rate exceeded 95%, with product purity within specification for pipeline transport and enhanced oil recovery (EOR) injection after supplemental purification. Net thermal efficiency for steam-and-power coproduction reached 38 to 42%, with significantly less capital equipment and fewer consumables than incumbent capture configurations. Syngas, tail gas, biomass, and RDF were utilized directly in the process without prior gasification, and petroleum coke was evaluated through characterization and validated process modeling, broadening the addressable feedstock envelope relative to oxy-fuel, gasification, steam methane reforming (SMR), or autothermal reforming (ATR) routes. Modeled specific CO2 isolation and purification cost was less than $35 per tonne CO2, compared with $160 to $210 per tonne for retrofit monoethanolamine (MEA) capture on equivalent units. Oxygen carrier circulation and attrition were stable over thousands of redox cycles, and NOx emissions are inherently low owing to the absence of N2 in the fuel reactor. Integration analysis indicated delivered CO2 cost reductions relative to retrofit alternatives ranging from approximately 50% for high-pressure, pipeline-quality CO2-EOR to greater than 80% for low-pressure applications such as local geological injection. Given U.S. commercial activity and extensive testing of similar feedstocks, iron-based chemical looping is ready for Middle East development and deployment.
Degradation of steam generator (SG) tubing by localized corrosion is a widespread problem in the nuclear industry that can lead to costly forced outages, unit de-rating, SG replacement or even the permanent shutdown of a reactor. In response to the onset of SG tubing degradation at Ontario Hydro's Pickering Nuclear Generating Station (PNGS) Unit 5, and the determined unsuitability of conventional repair methods (mechanically expanded or welded sleeves) for Alloy 400, an alternative repair technology was developed. Electrosleeve is a non-intrusive, low-temperature process that involves the electrodeposition of a nanocrystalline nickel microalloy forming a continuously bonded, structural layer over the internal diameter of the degraded region. This technology is designed to provide a long-term pressure boundary repair, fully restoring the structural integrity of the damaged region to its original state. This paper describes the Electrosleeve process for SG tubing repair and the unique properties of the advanced sleeve material. The successful installation of Electrosleeves that have been in service for more than three years in Alloy 400 SG tubing at the Pickering-5 CANDU unit, the more recent extension of the technology to Alloy 600 and its demonstration in a U.S. pressurized water reactor (PWR), is presented. A number of PWR operators have requested plant operating technical specification changes to permit Electrosleeve SG tube repair. Licensing of the Electrosleeve by the U.S. Nuclear Regulatory Commission (NRC) is expected imminently.
The steam generators at Hydro Quebec's Gentilly-2 and New Brunswick Power's Point Lepreau Nuclear Plants have been in operation since 1983, and were built with primary divider plates of a bolted panel configuration. During a routine outage inspection at Gentilly-2, it was noted that two bolts had dislodged from the divider plate and were located lying in the primary head. Subsequent inspections revealed erosion damage to a substantial number of divider plate bolts and to a lesser extent, to the divider plate itself. After further inspection and repair the units were returned to operation, however, it was determined that a permanent replacement of the primary divider plates was going to be necessary. Upon evaluation of various options, it was decided that the panel type divider plates would be replaced with a single piece floating design. The divider plate itself was to be of a one piece all-welded arrangement to be constructed from individual panels to be brought in through the manways. In view of the strength limitations of the bolted attachment of the upper seat bar to the tubesheet, a new welded seat bar was provided To counteract erosion concerns, the new divider plate is fitted with erosion resistant inserts or weld buildup and with improved sealing features in order to minimize leakage and erosion. At an advanced stage m the design and manufacture of the components, the issue of divider plate strength during loss of coolant accident (LOCA) conditions came into focus. Analysis was performed to determine the strength and/or failure characteristics of the divider plate to a variety of small and large LOCA conditions. Subsequently, Point Lepreau decided to replace their divider plates to address LOCA concerns. The paper describes the diagnosis of the original divider plates and the design, manufacture, field mobilization, installation and subsequent operation of the replacement divider plates.
This paper was not ready when these proceedings were being printed.
The primary heat transport system pressurizer vessels at Darlington NGS have required a substantial maintenance of the gasketed joints. Two of these joints are the upper inspection port and the lowery manway. In at least one instance there has been erosion damage to the carbon steel sealing faces from leakage of the high energy primary fluid. In the work described in the paper, each of the two closures was re-engineered to incorporate a seal welded diaphragm in place of the gasket. This approach for which patent protection is sought, required machining and weld build up of the nozzle gasket area to facilitate seal welding of a custom diaphragm plate. The closure covers were modified to support the diaphragm and were reinstalled using the original bolting arrangement. The paper describes the re-engineering of these closures as well as the retrofit of the seal welded diaphragms in the field.
