FAST-PYROLYSIS OF BIOMASS RELATED MODEL COMPOUNDS: A NOVEL APPROACH TO EXPERIMENTAL STUDY AND MODELING

Fast pyrolysis is a potentially attractive method for converting biomass to a low energy-density liquid (bio-oil) that can be further upgraded for use as fuel. Currently there is no agreement concerning the reaction pathways and mechanisms for pyrolysis of any individual component of biomass. This information is important for optimization of the fast-pyrolysis process. The work was divided into four areas, 1--development and validation of analytical methods and reactors, 2--the utilization of these methods to study pyrolysis of biomass and related models, 3--use of available biomass conversion pathways to propose potential integration with the existing fuel and chemicals markets, and 4--a proposed kinetic and multiphase reactor model for the physical and chemical processes that occur during pyrolysis

Stratigraphy of Paleocene and Pleistocene Sediments Exposed Along Lake Sakakawea in Eastern Dunn and Western and Central Mercer Counties, North Dakota

The bluffs of Lake Sakakawea, west- central North Dakota, provide excellent exposures of the Paleocene Sentinel Butte Formation and Pleistocene glacial deposits of the Coleharbor Group. The dominant sediment type in the Sentinel Butte Formation is thinly-bedded silt. Fine sand, clay, and lignite occur in lesser abundance. Lignite, clay, and peat are most commonly bounded by thinly-bedded silt. No lignite beds greater than five feet are present in the study area. The complete section of the Sentinel Butte Formation was not present in bluff exposures of the study area. The maximum exposed thickness of the Sentinel Butte Formation was 110 feet. Extreme lateral variability of lithology made detailed correlations exceedingly difficult, even across small distances such as from one bluff to the next. Glacial deposits of the Coleharbor Group are more common in bluff exposures in the eastern part of the study area and become less common and extensive towards the western edge of the study area. At least two separate units of pebble loam are present in the eastern part of the study area. Gravel and bedded silt crop out in the eastern part of the study area. Thicknesses of glacial drift in bluff exposures range from 0 to 30 feet. The glacial deposits seem to be restricted to former topographic low areas. Erosion by waves and ground water sapping is substantial, resulting in considerable land loss. This erosion is greater along the south shore of the lake

Geology of the Flathead Formation (Middle Cambrian) on the perimeter of the Bighorn Basin, Beartooth Mountains, and Little Belt Mountains in Wyoming and Montana

The Flathead Formation, which is 4 to 60 metres thick in the middle and northern Rocky Mountains of Wyoming and Montana, contains cross-bedded and parallel-bedded, quartz sandstone. The formation contains marginal-marine and shallow-marine sediment that was deposited unconformably on Precambrian crystalline and sedimentary rock by an eastward-transgressing sea during middle Cambrian time. This field study of the Flathead Formation on the perimeter of the Bighorn Basin, Beartooth Mountains, and Little Belt Mountains reveals that the formation consists of three intervals. The lower interval contains medium to very coarse, pebbly, cross-bedded sandstone and conglomerate. The middle interval contains medium to coarse, cross-bedded, quartz sandstone. Cross beds dip to the west in most places, but some cross beds dipping north, south, and east are present. The upper interval contains fine to coarse, parallel-bedded, quartz sandstone. Trace fossils are present in the middle and upper intervals. Skclithos, Monocraterion, and Rusophycus have been identified. Horizontal tubes on bedding planes are the most common trace fossils. Large vertical tubes containing smaller Skolithos tubes and bedding deflected downward in a cone-in-cone fashion were formed by anemones moving upwards in their dwelling tubes. Inarticulate brachiopods are present in the upper interval in some places. The brachiopods, which are the first to be identified in the formation belong to three genera. Comparison of the characteristics of the Flathead Formation with modern shallow-marine and marginal-marine environments indicates the sandstone was deposited in a high-energy environment with wave-induced currents. A barrier island was not present in most places. The sandstone was deposited on a weathered Precambrian surface with 3 metres of relief, but up to 70 metres of relief was present in some places. The thickness of the Flathead Formation varies with the amount of surface relief, Resistant knobs of Precambrian rock existed as islands in the Owl Creek Mountain area

Near-Zero Emissions Oxy-Combustion Flue Gas Purification Task 2: SOx/Nox/Hg Removal for High Sulfur Coal

The goal of this project is to develop a near-zero emissions flue gas purification technology for existing PC (pulverized coal) power plants that are retrofitted with oxy-combustion technology. The objective of Task 2 of this project was to evaluate an alternative method of SOx, NOx and Hg removal from flue gas produced by burning high sulfur coal in oxy-combustion power plants. The goal of the program was not only to investigate a new method of flue gas purification but also to produce useful acid byproduct streams as an alternative to using a traditional FGD and SCR for flue gas processing. During the project two main constraints were identified that limit the ability of the process to achieve project goals. 1) Due to boiler island corrosion issues >60% of the sulfur must be removed in the boiler island with the use of an FGD. 2) A suitable method could not be found to remove NOx from the concentrated sulfuric acid product, which limits sale-ability of the acid, as well as the NOx removal efficiency of the process. Given the complexity and safety issues inherent in the cycle it is concluded that the acid product would not be directly saleable and, in this case, other flue gas purification schemes are better suited for SOx/NOx/Hg control when burning high sulfur coal, e.g. this project's Task 3 process or a traditional FGD and SCR

Odin–OSIRIS detection of the Chelyabinsk meteor

On 15 February 2013 an 11 000 ton meteor entered Earth's atmosphere southeast of Chelyabinsk, creating a large fireball at 23 km altitude. The resulting stratospheric aerosol loading was detected by the Ozone Mapping and Profiler Suite (OMPS) in a high-altitude polar belt. This work confirms the presence and lifetime of the stratospheric debris using the Optical Spectrograph and InfraRed Imaging System (OSIRIS) onboard the Odin satellite. Although OSIRIS coverage begins in mid-March, the measurements show a belt of enhanced scattering near 35 km altitude between 50° N and 70° N. Initially, enhancements show increased scattering of up to 15% over the background conditions, decaying in intensity and dropping in altitude until they are indistinguishable from background conditions by mid-May. An inversion is also attempted using the standard OSIRIS processing algorithm to determine the extinction in the meteoric debris

Retrieval of stratospheric aerosol size information from OSIRIS limb scattered sunlight spectra

International audienceRecent work has shown that the retrieval of stratospheric aerosol vertical profiles is possible using limb scattered sunlight measurements at optical wavelengths. The aerosol number density profile is retrieved for an assumed particle size distribution and composition. This result can be used to derive the extinction at the measured wavelength. However, large systematic error can result from the uncertainty in the assumed size distribution when the result is used to estimate the extinction at other wavelengths. It is shown in this work that the addition of information obtained from the near infrared limb radiance profile at 1530 nm measured by the imaging module of the OSIRIS instrument yields an indication of the aerosol size distribution profile that can be used to improve the fidelity of the retrievals. A comparison of the estimated extinction profile at 1020 nm with coincident occultation measurements demonstrates agreement to within approximately 15% from 12 to 27 km altitude

11-year solar cycle influence on OH (3-1) nightglow observed by OSIRIS

In the mesosphere, the vibrationally excited hydroxyl layer is sensitive to changes in incoming solar flux. An enhanced photodissociation of molecular oxygen will lead to more atomic oxygen production, thus we expect the OH layer emission rate to be positively with the Lyman-α flux and the emission height to be negatively correlated. The Optical Spectrograph and InfraRed Imager System (OSIRIS) has recorded the Meinel band centred at 1.53 μm from 2001 to 2015. In this study, we show how the 11-year solar cycle signature manifests itself in this data set, in terms of OH zenith emission rate and emission height. As expected, the emission height is negatively correlated with the Lyman-α flux at all latitudes. The zenith emission rate is positively correlated with the Lyman-α flux at most latitudes except near the equator. By the means of a time dependent photochemical model, we show that the changing local time sampling of the Odin satellite was the cause of the observed distortion of the solar cycle signature near the equator

Odin-OSIRIS stratospheric aerosol data product and SAGE III intercomparison

The scattered sunlight measurements made by the Optical Spectrograph and InfraRed Imaging System (OSIRIS) on the Odin spacecraft are used to retrieve vertical profiles of stratospheric aerosol extinction at 750 nm. The recently released OSIRIS Version 5 data product contains the first publicly released stratospheric aerosol extinction retrievals, and these are now available for the entire Odin mission, which extends from the present day back to launch in 2001. A proof-of-concept study for the retrieval of stratospheric aerosol extinction from limb scatter measurements was previously published and the Version 5 data product retrievals are based on this work, but incorporate several important improvements to the algorithm. One of the primary changes is the use of a new retrieval vector that greatly improves the sensitivity to aerosol scattering by incorporating a forward modeled calculation of the radiance from a Rayleigh atmosphere. Additional improvements include a coupled retrieval of the effective albedo, a new method for normalization of the retrieval vector to improve signal-to-noise, and the use of an initial guess that is representative of very low background aerosol loading conditions, which allows for maximal retrieval range. Furthermore, the Version 5 data set is compared to Stratospheric Aerosol and Gas Experiment (SAGE) III 755 nm extinction profiles during the almost four years of mission overlap from 2002 to late 2005. The vertical structure in coincident profile measurements is well correlated and the statistics on a relatively large set of tight coincident measurements show agreement between the measurements from the two instruments to within approximately 10% throughout the 15 to 25 km altitude range, which covers the bulk of the stratospheric aerosol layer for the mid and high latitude cases studied here

Retrieval of subvisual cirrus cloud optical thickness from limb-scatter measurements

We present a technique for estimating the optical thickness of subvisual cirrus clouds detected by OSIRIS (Optical Spectrograph and Infrared Imaging System), a limb-viewing satellite instrument that measures scattered radiances from the UV to the near-IR. The measurement set is composed of a ratio of limb radiance profiles at two wavelengths that indicates the presence of cloud-scattering regions. Cross-sections and phase functions from an in situ database are used to simulate scattering by cloud-particles. With appropriate configurations discussed in this paper, the SASKTRAN successive-orders of scatter radiative transfer model is able to simulate accurately the in-cloud radiances from OSIRIS. Configured in this way, the model is used with a multiplicative algebraic reconstruction technique (MART) to retrieve the cloud extinction profile for an assumed effective cloud particle size. The sensitivity of these retrievals to key auxiliary model parameters is shown, and it is shown that the retrieved extinction profile, for an assumed effective cloud particle size, models well the measured in-cloud radiances from OSIRIS. The greatest sensitivity of the retrieved optical thickness is to the effective cloud particle size. Since OSIRIS has an 11-yr record of subvisual cirrus cloud detections, the work described in this manuscript provides a very useful method for providing a long-term global record of the properties of these clouds

Near-Zero Emissions Oxy-Combustion Flue Gas Purification Task 2: SOx/Nox/Hg Removal for High Sulfur Coal

The goal of this project is to develop a near-zero emissions flue gas purification technology for existing PC (pulverized coal) power plants that are retrofitted with oxy-combustion technology. The objective of Task 2 of this project was to evaluate an alternative method of SOx, NOx and Hg removal from flue gas produced by burning high sulfur coal in oxy-combustion power plants. The goal of the program was not only to investigate a new method of flue gas purification but also to produce useful acid byproduct streams as an alternative to using a traditional FGD and SCR for flue gas processing. During the project two main constraints were identified that limit the ability of the process to achieve project goals. 1) Due to boiler island corrosion issues >60% of the sulfur must be removed in the boiler island with the use of an FGD. 2) A suitable method could not be found to remove NOx from the concentrated sulfuric acid product, which limits sale-ability of the acid, as well as the NOx removal efficiency of the process. Given the complexity and safety issues inherent in the cycle it is concluded that the acid product would not be directly saleable and, in this case, other flue gas purification schemes are better suited for SOx/NOx/Hg control when burning high sulfur coal, e.g. this project's Task 3 process or a traditional FGD and SCR