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Sediment Sensors for Hydro Power
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Sediment (Silt) Monitoring for Turbine Erosion Prevention in Run of River Hydro Power Plants Using LISST-Infinite and LISST-Hydro.
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LISST-Infinite assembly
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run of river power plants, severe erosion of turbine parts can occur due to sediments carried by rivers, despite the presence of desiltation
chambers. The problem is severe in power plants that are sited in the
steep terrains, e.g. the Himalayan topography, or in regions with rivers carrying large amounts of sediment, e.g. South America.
Turbines, wicket gates, valves
etc. can suffer severe erosion if the size of suspended sediment grains
is large. Convention has it that grains >200 microns cause the most
severe damage. As a result, often desiltation efficiency is described
in terms of the removal of such large grains. In fact, there is no
sharp cut-off in size below which grains may cause no turbine erosion.
Thus, a measurement of the full size distribution of suspended
sediments is needed at all times.
The erosion of turbines in Hydro Power plants is known to be a severe
problem in rivers that drain the Himalayas - covering India, China,
Nepal, Bhutan and other countries of East Asia. In Europe, power plants in Switzerland and Norway also are subject to such
erosion and wear. In South America, power plants in Colombia, Brazil, Ecuador, Chile and Bolivia suffer from the same damages.
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LISST-HYDRO front panel
| | Sequoia Scientific, Inc. has
developed the world's first instrument system geared to
the automated at-site MONITORING of the suspended sediment size
distribution
and concentration. Two different systems have been developed; one with
and one without an auto-dilution system. These two systems are called
LISST-Infinite and LISST-HYDRO, respectively. Using our basic laser
diffraction technology the concentration and size
distribution can be routinely and continuously monitored.
The LISST-HYDRO is quite similar to Sequoia's LISST-StreamSide instrument, but with the capability to talk to our LISST-Infinite Monitor software for displaying real-time size and concentration in a control room environment.
| | | | | | | | | | Both systems consists of a laser optical flow through cell. The user
must provide power and clean filtered water. The
instruments monitors the sediment properties on a user selected
schedule. When the concentration exceeds a factory pre-set
threshold, the LISST-Infinite will perform a dilution step before
making a measurement of the concentration and size distribution.
Typically, below about 2,000 mg/l (precise number depends on sediment
size) no dilution is required. Thus, the upper range of concentration
that the LISST-HYDRO can work in is around 2,000 mg/l. For the
LISST-Infinite, the upper concentration limit is around 30,000 mg/l. See the article 'LISST Concentration Limits' for more information on what influences these limits.
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| | Some capabilities are shared between the LISST-Infinite and the LISST-HYDRO. The list below details these shared capabilities. |
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| | - Measurement of size distribution and concentration; the size distribution reports concentration in 32 log-spaced size classes covering the size range from 2.5 to 500 microns
| | | | | | |  | | - Control Room strip chart display of history and current data on a dedicated computer;
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| - Systems can be programmed to set off alarms at user-selected thresholds in user-selected size classes
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| | | | | | | - Data can be archived, archived and hard-wired, or archived and telemetered to a remote site via RF or satellite links.
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| | | | | | | | | | | | | | Additionally, the LISST-Infinite has the following capabilities unique to the LISST-Infinite: | | | | | | |  | | - Auto-dilution
system for continued operation in high-concentration environments
(concentration in excess of 2,000 mg/l).
- The auto-dilution system consists of a dilution chamber, a mixer pump and a pinch valve system. The pinch valves enable the LISST-Infinite to capture a small sample of turbid water, transfer it to the dilution chamber where it is diluted 10:1, and then recirculated using the mixer pump through the optics system for a second measurement.
- With the dilution, the upper concentration range is extended to about 30,000 mg/l (ppm by mass).
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| | | | | | | | | Sequoia is pleased to offer a complete turn-key solution from
installation to data display and alarm settings (but not including
civil works). For more information about capabilities, as well as installation requirements and shared responsibilities between customer and Sequoia, please click here.
| | | | | | | | | | For price quotes, please contact us. | | | | | | | | | |
Related Links
| | | | | | | Updated 6/15/2011
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|  | | Sequoia visit to Colombia and Ecuador! |  | | Sequoia's Yogi Agrawal and Ole Mikkelsen visited C'Particulas, Sequoia's Colombian distributor 28-30 November 2011. See the pictures on our facebook page! | |  | |  | |
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