Retrofit of Corn Ethanol Plant to Produce Biobutanol through Fermentation

The depletion of natural gas resources coupled with the improved technologies for biofuel production present a favorable scenario for entry into the biobutanol market. This process aims to produce butanol at a competitive price to oil and natural gas produced from petrochemical processes. As such, the proposed design takes an existing 40MM gpy corn ethanol plant and retrofits the plant to produce butanol via continuous fermentation of corn using a genetically engineered strain of Clostridia. The proposed design consumes 14.5 million bushels of corn per year and produces acetone, butanol and ethanol at a mass ratio of 12:58:1, respectively. The corn is undergoes traditional wet mill processing upstream, and is then fed as a slurry to the fermenters. The liquid fermentation products pass through liquid-liquid extraction followed by distillation to recover the butanol and acetone. The solids pass through a DDGS separation section and the vapor phase leaving the fermenters is combusted. This process intends to produce butanol, acetone, and DDGS for sale in the market. The plant has the capacity to operate 330 days per year and to produce 21.7MM gpy of butanol at 99.5% purity, 2.8MM gpy of acetone at 93.2% purity and 182,509 metric tons of DDGS per year. The plant is located in the Midwest United States in the Corn Belt. It has a return on investment of 12.07%

Pollution from Aircraft Emissions in the North Atlantic Flight Corridor: Overview on the POLINAT Projects

The Pollution From Aircraft Emissions in the North Atlantic Flight Corridor (POLINAT) projects were undertaken to investigate the impact of aircraft engine exhaust emissions on the state of the atmosphere in the North Atlantic flight corridor. Changes in the composition of the lower stratosphere and upper troposphere from aircraft emissions are identified from combined measurements and model analyses. Measurements were performed using the Deutsches Zentrum für Luft- und Raumfahrt Falcon research aircraft and a Swissair B-747 over the North Atlantic covering the altitude range 6 to 13 km in November 1994 and June/July 1995 and from August to November 1997. The measurements include those of nitrogen oxides, nitrous and nitric acids, sulfur dioxide, sulfuric acid, acetone, carbon dioxide, ozone, water vapor, carbon monoxide, aerosols, and meteorological parameters. The atmospheric composition was found to be highly variable, and emissions from sources at the surface or from lightning discharges also contribute strongly to the nitrogen oxides abundance and ozone formation. Contributions from aircraft emissions have been measured and identified in single and multiple plumes of several hours ages, and accumulation of such nitrogen oxides and particles emissions can be identified under certain conditions in and downstream of the flight corridor region. Acetone was found at high mixing ratios. The global and regional models predict ozone increases of 3 to 6% by current air traffic at the flight corridor altitude north of 30°N, in agreement with previous model analyses but too small to be measurable. In autumn, the upper troposphere is often humid with water vapor concentration far above ice saturation, providing conditions for persistent contrails

Data composites of airborne observations of tropospheric ozone and its precursors

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