Provided are emissions treatment systems for an exhaust stream having an ammonia-generating component, such as a NOx storage reduction (NSR) catalyst or a lean NOx trap (LNT) catalyst, and an SCR catalyst disposed downstream of the ammonia-generating catalyst. The SCR catalyst can be a molecular sieve having the CHA crystal structure, for example SSZ-13 or SAPO-34, which can be ion-exchanged with copper. The LNT can be layered, having an undercoat washcoat layer comprising a support material, at least one precious metal, and at least one NOx sorbent selected from the group consisting of alkaline earth elements, rare earth elements, and combinations thereof and a top washcoat layer comprising a support material, at least one precious metal, and ceria in particulate form, the top washcoat layer being substantially free of alkaline earth components. The emissions treatment system is advantageously used for the treatment of exhaust streams from diesel engines and lean burn gasoline engines.

The present invention concerns a process for producing ammonia synthesis gas from the reforming of hydrocarbons with steam in a primary reformer (1) equipped with a plurality of externally heated catalytic tubes and then in a secondary reformer (2) together with an oxidant gas. In this process, the reaction of said hydrocarbons with said steam in said primary reformer (1) is performed at an operating pressure of at least 45 bar in the catalytic tubes and a flow of essentially pure oxygen or oxygen-enriched air is added to said secondary reformer as oxidant gas for substantially reforming together with said all the hydrocarbons content of said product gas exiting the primary reformer (1). In the case essentially pure oxygen is used as oxidant gas, a flow of nitrogen is added downstream the secondary reformer (2) to reach a N2/H2 molar ratio corresponding to or close to the stoichiometric ratio for ammonia synthesis. This process allows to obtain high synthesis gas production capacities and lower investment and energy costs.

Alaska’s 720,000 people live in over 200 “energy islands” with no electricity grid connection to each other nor to North America. Smaller communities have no road connection to each other, the rest of Alaska, or the continent. Most energy is imported: diesel for electricity generation and heat; gasoline for transportation. All Alaskans might obtain an annually-firm supply of most of their energy, for all purposes, by converting Alaska’s diverse, stranded, renewable energy (RE) resources to liquid anhydrous ammonia (NH3) fuel, transporting and storing it at low cost in common steel propane tanks, recovering the RE via stationary combined-heat-and-power (CHP) plants, in internal combustion engine (ICE) and combustion turbine (CT) gensets, and via fuel cells, and as transportation fuel. Alaskans could achieve a significant degree of community energy independence, and perhaps export their abundant, stranded renewables as “green” liquid NH3 fuel. Solid state ammonia synthesis (SSAS) appears promising.

ABSTRACT

The recent discovery of complete ammonia oxidizers (comammox) contradicts the paradigm that chemolithoautotrophic nitrification is always catalyzed by two different microorganisms. However, our knowledge of the survival strategies of comammox in complex ecosystems, such as full-scale wastewater treatment plants (WWTPs), remains limited. Analyses of genomes and in situ transcriptomes of four comammox organisms from two full-scale WWTPs revealed that comammox were active and showed a surprisingly high metabolic versatility. A gene cluster for the utilization of urea and a gene encoding cyanase suggest that comammox may use diverse organic nitrogen compounds in addition to free ammonia as the substrates. The comammox organisms also encoded the genomic potential for multiple alternative energy metabolisms, including respiration with hydrogen, formate, and sulfite as electron donors. Pathways for the biosynthesis and degradation of polyphosphate, glycogen, and polyhydroxyalkanoates as intracellular storage compounds likely help comammox survive unfavorable conditions and facilitate switches between lifestyles in fluctuating environments. One of the comammox strains acquired from the anaerobic tank encoded and transcribed genes involved in homoacetate fermentation or in the utilization of exogenous acetate, both pathways being unexpected in a nitrifying bacterium. Surprisingly, this strain also encoded a respiratory nitrate reductase which has not yet been found in any other Nitrospira genome and might confer a selective advantage to this strain over other Nitrospira strains in anoxic conditions.

IMPORTANCE The discovery of comammox in the genus Nitrospira changes our perception of nitrification. However, genomes of comammox organisms have not been acquired from full-scale WWTPs, and very little is known about their survival strategies and potential metabolisms in complex wastewater treatment systems. Here, four comammox metagenome-assembled genomes and metatranscriptomic data sets were retrieved from two full-scale WWTPs. Their impressive and—among nitrifiers—unsurpassed ecophysiological versatility could make comammox Nitrospira an interesting target for optimizing nitrification in current and future bioreactor configurations.

Human activities and population growth have increased the natural burden of reactive nitrogen (N) in the environment. Excessive N deposition on Earth’s surface leads to adverse feedbacks on ecosystems and humans. Similar to that of air pollution, emission control is recognized as an efficient means to control acid deposition. Control...

A pipeline company and two of its former operating firms will jointly pay a civil penalty of $3.65 million to resolve violations of the Clean Water Act resulting from anhydrous ammonia spills in Nebraska and Kansas, the Justice Department and U.S. Environmental Protection Agency announced today. The spills which occurred in 2004 resulted in significant fish kills in surrounding waterways.

The U.S. Department of Justice and the U.S. Environmental Protection Agency (EPA) announced a Clean Air Act (CAA) settlement with Tyson Foods Inc. and several of its affiliate corporations to address threats of accidental chemical releases after anhydrous ammonia was released during incidents at facilities in Kansas, Missouri, Iowa and Nebraska, resulting in multiple injuries, property damage and one fatality.

Marine operators are looking to clean up their act

Brownfield Ammonia-Urea plant

Black, Silvia Beatriz

Woodward, Travis M., author

D'Aloya de Pinilla, Anna, author

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Crown ethers simplify the set-up of classic reaction