Mareth, Brett (2006-08). A reverse osmosis treatment process for produced water: optimization, process control, and renewable energy application. Master's Thesis. Thesis uri icon

abstract

  • Fresh water resources in many of the world's oil producing regions, such as
    western Texas, are scarce, while produced water from oil wells is plentiful, though unfit
    for most applications due to high salinity and other contamination. Disposing of this
    water is a great expense to oil producers. This research seeks to advance a technology
    developed to treat produced water by reverse osmosis and other means to render it
    suitable for agricultural or industrial use, while simultaneously reducing disposal costs.
    Pilot testing of the process thus far has demonstrated the technology's capability to
    produce good-quality water, but process optimization and control were yet to be fully
    addressed and are focuses of this work. Also, the use of renewable resources (wind and
    solar) are analyzed as potential power sources for the process, and an overview of
    reverse osmosis membrane fouling is presented.
    A computer model of the process was created using a dynamic simulator, Aspen
    Dynamics, to determine energy consumption of various process design alternatives, and
    to test control strategies. By preserving the mechanical energy of the concentrate stream
    of the reverse osmosis membrane, process energy requirements can be reduced several
    fold from that of the current configuration. Process control schemes utilizing basic
    feedback control methods with proportional-integral (PI) controllers are proposed, with
    the feasibility of the strategy for the most complex process design verified by successful
    dynamic simulation. A macro-driven spreadsheet was created to allow for quick and
    easy cost comparisons of renewable energy sources in a variety of locations. Using this
    tool, wind and solar costs were compared for cities in regions throughout Texas. The
    renewable energy resource showing the greatest potential was wind power, with the
    analysis showing that in windy regions such as the Texas Panhandle, wind-generated
    power costs are approximately equal to those generated with diesel fuel.

publication date

  • August 2006