Laboratory Experiments to Stimulate CO(2) Ocean Disposal

This Technical Progress Report summarizes activities conducted over the period 8/16/96-2/15/97 as part of this project. This investigation responds to the possibility that restrictions on greenhouse gas emissions may be imposed in the future to comply with the Framework Convention on Climate Change. The primary objective of the investigation is to obtain experimental data that can be applied to assess the technical feasibility and environmental impacts of oceanic containment strategies to limit release of carbon dioxide (CO{sub 2}) from coal and other fossil fuel combustion systems into the atmosphere. Critical technical uncertainties of ocean disposal of CO{sub 2} will be addressed by performing experiments that: (1) characterize size spectra and velocities of a dispersed CO{sub 2} phase in the near-field of a discharge jet; and (2) estimate rates of mass transfer from dissolving droplets of liquid CO{sub 2} encased in a thin hydrate shell. Experiments will be conducted in a laboratory facility that can reproduce conditions in the ocean to depths of 600 m (1,969 ft). Between 8/16/96 and 2/15/97, activities focused on modifications to the experimental apparatus and the testing of diagnostics. Following completion of these tasks, experiments will be initiated and will continue through the end of the 36 month period of performance. Major accomplishments of this reporting period were: (1) delivery, set-up, and testing of the PDPA (Phase Doppler Particle Analyzer), which will be the principal diagnostic of the continuous CO{sub 2} jet injection tests; (2) presentation of research papers and posters at the 212th American Chemical Society National Meeting and the Third International Conference on Carbon Dioxide Removal; (3) participation in the 4th Expert Workshop on Ocean Storage of Carbon Dioxide; (4) execution of an Agreement with ABB Management, Ltd. to support and extend the activities of this grant; and (5) initiation of research collaborations with Dr. P.M. Haugen of the University of Bergen, Norway, and Dr. A. Yamasaki of the National Institute of Materials and Chemical Research, Japan

Summary, biomass gasifier facility start-up tests - October and December 1995

Shakedown testing of the biomass gasifier facility, located at the Hawaiian Commercial and Sugar Co. factory in Paia on the island of Maui, utilizing sugarcane bagasse, occurred in October 1995. Input and output streams for the process were sampled during three periods of steady-state operation in an air-blown mode. Additional tests were carried out in early December, 1995. Air and a mixture of air and steam were utilized as the fluidizing agent in the December operations, with two sampling periods occurring during air gasification and a single period under air-steam-blown conditions. This summary reports average values for the October test period, the December air-blown tests and the December air-steam tests (see following table). Details of individual tests are presented in the body of this report. During the October sampling periods, the average reactor temperature and pressure were 1545{degrees}F (840{degrees}C) and 43 psi (300 kPa), respectively. Bagasse from the sugar factory entered the dryer at a nominal moisture content of 45% and exited at 26%, wet basis. Wet fuel feed rate to the reactor averaged 1.2 ton hr{sup -1} (1.1 tonne hr{sup -1}). Average gas composition determined over the sample periods was 4% H{sub 2}, 10% CO, 18% CO{sub 2}, 3% CH{sub 4}, 1% C{sub 2}`s and higher hydrocarbons, and the balance N{sub 2}. The higher heating value of the gas was 100 Btu ft{sup -3} (3.7 MJ m{sup -3}). Condensable hydrocarbons (C{sub 6} and higher) in the output stream averaged 2.3% of dry fuel feed with benzene (C{sub 6}H{sub 6}) and naphthalene (C{sub 10}H{sub 8}) being the principal constituents. Carbon conversion efficiency, defined as the percentage of fuel carbon converted into gas or liquids, was estimated to be {approximately}96%

The uses of coherent structure (Dryden Lecture)

The concept of coherent structure in turbulent flow is a revolutionary idea which is being developed by evolutionary means. The main objective of this review is to list some solid achievements, showing what can be done by using the concept of coherent structure that cannot be done without it. The nature of structure is described in terms of some related concepts, including celerity, topology, and the phenomenon of coalescence and splitting of structure. The main emphasis is on the mixing layer, as the one flow whose structure is well enough understood so that technical applications are now being made in problems of mixing and chemistry. An attempt is made to identify some conceptual and experimental obstacles that stand in the way of progress in other technically important flows, particularly the turbulent boundary layer. A few comments are included about the role of structure in numerical simulations and in current work on manipulation and control of turbulent flow. Some recent developments are cited which suggest that the time is nearly right for corresponding advances to occur in turbulence modeling

Laboratory experiments to simulate CO{sub 2} ocean disposal. Draft technical progress report, August 15, 1995--February 15, 1996

The primary objective of this investigation is to obtain experimental data that can be applied to assess the technical feasibility and the environmental impacts of oceanic containment strategies to limit atmospheric emissions of carbon dioxide from coal and other fossil fuel combustion systems. These strategies exploit the very large storage capacity of the deep ocean. In most systems proposed to date, CO{sub 2} extracted from a combustor is liquefied and transported to the deep ocean via a submerged conduit and discharged, usually as a jet. Hydrodynamic instability induces break-up of the jet into droplets which will be buoyant at depths above 3,000m. Dissolution of the rising droplets may be inhibited by a solid hydrate film that forms on the surface of the droplets. The complex mechanisms of liquid CO{sub 2} jet break-up, droplet dispersion and coalescence, and dissolution in the deep ocean environment are not well understood. The present investigation seeks to address several of the major technical uncertainties by conducting two categories of laboratory tests which will: (1) characterize size spectra and velocities of the dispersed CO{sub 2} phase in the near-field of the atomized jet; and (2) estimate rates of mass transfer from single rising droplets of liquid CO{sub 2} encased in a thin hydrate shell

Resolved Scalar Mixing in Large Eddy Simulations of a Low Reynolds Number Plane Mixing Layer

Resolved Scalar Mixing in Large Eddy Simulations of a Low Reynolds Number Plane Mixing Laye