A solid oxide fuel cell (SOFC) is a clean and efficient energy conversion device. The development of intermediate-temperature SOFCs has made it preferable to use metallic interconnects (MICs) to greatly reduce the cost and significantly increase the efficiency compared to ceramic interconnect materials. However, gaseous chromium species will evaporate from the chromium-containing layer formed on the surface of commonly used MICs. Volatile chromium species have been shown to form solid deposits which poison the cathodes of SOFCs, causing drastic cell performance degradation and thereby limiting commercialization. In this review, we systematically summarize the status and progress of research on this topic and compare the variations in chromium poisoning phenomena under numerous SOFC operating conditions. Moreover, approaches to alleviate chromium poisoning are evaluated and discussed.

Comprehensive review of chromium deposition and poisoning of solid oxide fuel cells (SOFCs) cathode materials

This paper highlights some of the major findings of the Alkali Deposits Investigation, a collaborative effort to understand the causes of unmanageable ash deposits in biomass-fired electric power boilers. A group of interested industrial institutions and the US DOE Energy Efficiency and Renewable Energy Office's Biomass Power Program through the National Renewable Energy Laboratory jointly sponsored the project. The industries contributed both funding and, in most cases, use of facilities to the project and included Mendota Biomass Power and Woodland Biomass Power (both associated with Thermo Electron Energy Systems), CMS Generation Operating (formerly Hydra-Co Operations), Wheelabrator, Shasta and Hudson Energy, Sithe Energy, Delano Energy, the Electric Power Research Institute, Foster Wheeler Development, and Elkraft Power of Denmark. Research contracts with Thomas R. Miles Consulting Design Engineers, Sandia National Laboratories, and The National Renewable Energy Laboratories provided the government portion of the funding. In addition, the University of California at Davis and the Bureau of Mines performed significant work in close collaboration with the other researchers. This summary highlights the major findings of the project more thoroughly discussed in a recent report [2]. We highlight fuel properties, bench-scale combustion tests, a framework for considering ash deposition processes, pilot-scale tests of biomass fuels, and field tests in commercially operating biomass power generation stations. Detailed chemical analyses of 11 biomass fuels representing a broad cross-section of commercially available fuels reveal their properties that relate to ash deposition tendencies. The fuels fall into three broad categories: (1) straws and grasses (herbaceous materials); (2) pits, shells, hulls and other agricultural by-products of a generally ligneous nature; and (3) woods and recycle fuels of commercial interest. Woods and wood-derived products represent the most commonly used biomass fuels. Herbaceous fuels contain silicon and potassium as their principal ash-forming constituents. They are also commonly high in chlorine relative to other biomass fuels. These properties portend potentially severe ash deposition problems at high or moderate combustion temperatures. The primary sources of these problems are shown to be: (1) the reaction of alkali with silica to form alkali silicates that melt or soften at low temperatures (can be lower than 700°C, depending on composition), and (2) the reaction of alkali with sulfur to form alkali sulfates on combustor heat transfer surfaces. Alkali material plays a central role in both processes. The mobility of alkali material, defined as its ability to come in physical contact with other materials, is measured using chemical extractive techniques. Potassium is the dominant source of alkali in most biomass fuels. The analyses below indicate that essentially, all of the biologically occurring alkali, in particular potassium, has high mobility. The non-biologically occurring alkali is present as soil contaminants and additives to the fuels, such as clay fillers used in paper production. This non-biologically occurring alkali exhibits far lower mobility than the biological fraction. The relative amounts of biologically vs. non-biologically occurring material depend on fuel type and fuel handling. In the fuels investigated here, the dominant form of alkali was biologically occurring potassium. Some traditional indicators of deposit behavior, most notably ash fusion temperatures, poorly predict ash behavior compared with a more mechanistic interpretation of the data. Many of the agricultural by-products also contain high potassium concentrations with equally high potassium mobility. Some woods, on the other hand, contain far less ash overall, differing by as much as a factor of 40 from high-ash straws, for example. In addition, the ash-forming constituents contain greater amounts of calcium with

The behavior of inorganic material in biomass-fired power boilers : field and laboratory experiences

Impact of wood combustion on indoor air quality.

Corrosion of stainless steels in the riser during co-processing of bio-oils in a fluid catalytic cracking pilot plant

Our research is focused on the development of decentralized waste water treatment technologies enabling onsite water reuse Accumulation of solids with recycling of treated blackwater increases the energy required for disinfection with an electrochemical process We hypothesized that improving the preprocess settling of blackwater by increasing the tortuosity of the liquid flow path would reduce this energy demand by reducing particle-associated chemical oxygen demand (COD) This approach successfully reduced the total suspended solids and turbidity in the process liquid accumulated per user-day equivalent A modest reduction in the apparent steady-state accumulation of COD was also observed, likely because of the retention of COD associated with larger particles in the settling tanks Interestingly, these improvements did not improve the energy efficiency of the electrochemical disinfection process, as predicted These observations suggest that improving the energy efficiency of electrochemical disinfection will require remediation of dissolved COD

https://onlinelibrary.wiley.com/doi/pdf/10.1111/wej.12369

Remediation of suspended solids and turbidity by improved settling tank design in a small-scale, free-standing toilet system using recycled blackwater.

Alloy Corrosion Considerations in Low-Cost, Clean Biomass Cookstoves for the Developing World

Synthesis of the α-Linked Digitoxose Trisaccharide Fragment of Kijanimicin: An Unexpected Application of Glycosyl Sulfonates.

Development and Field Testing of a Decentralized, Self-Contained Toilet that Converts Human Waste Into Burnable Fuel and Disinfected, Reusable Liquid

This investigation assesses the benefits of retrofitting a diesel micro-pilot ignition system on a Cooper-Bessemer GMV-4TF two-stroke cycle natural gas engine with a 14” (36 cm) bore and a 14” (36 cm) stroke. The pilot fuel injectors are mounted through an adaptor in one of the spark plug holes in a set of dual-spark plug heads. A high pressure, common-rail, diesel fuel delivery system is employed and customizable power electronics control the current signal to the pilot injectors. Pilot fuel is supplied by a variable displacement, high-pressure pump that is driven with an electric motor. Software is developed that interfaces with the pump and controls and monitors the fuel rail pressure. Micro-pilot quantities from 11.5 to 20 mm3 (.0007 to .0012 in3 ) are explored at rail pressures from 200 to 1400 bar (2,900 to 20,300 psig). Three independent variables, pilot ignition timing, pilot fuel quantity, and pilot fuel rail pressure, are manipulated. An optimization sequence is performed to minimize total fuel consumption.Copyright © 2003 by ASME

http://www.netl.doe.gov/File%20Library/Research/Oil-Gas/Natural%20Gas/41162_ICEF2003-762.pdf

On-Engine Demonstration of Micro-Pilot Ignition System for a Cooper-Bessemer GMV-4TF

Disclosed herein are systems and devices that aid in reducing particulate emissions from biomass stoves, for example by the use of gases injected in or near the oxidation zone of a combustion chamber. Also disclosed are systems and devices providing electricity to a pump or blower that aids in injecting the gas and/or collecting exhaust gases. In some embodiments the device providing electricity is a thermoelectric generator that may also be used to power other devices. In many embodiments, the systems and devices inject a gas at or near the oxidation zone in the combustion chamber of a biomass stove. The gas injected into the zone may be fresh air, exhaust from combustion or combinations thereof. The gas can be forced into the combustion chamber with the aid of a pump or blower that may also aid in drawing in exhaust gas.

John Mizia

Papers

Alloy Corrosion Considerations in Low-Cost, Clean Biomass Cookstoves for the Developing World

Synthesis of the α-Linked Digitoxose Trisaccharide Fragment of Kijanimicin: An Unexpected Application of Glycosyl Sulfonates.

Development and Field Testing of a Decentralized, Self-Contained Toilet that Converts Human Waste Into Burnable Fuel and Disinfected, Reusable Liquid

On-Engine Demonstration of Micro-Pilot Ignition System for a Cooper-Bessemer GMV-4TF

Side-feed forced-air biomass burning cookstove