Sand processing plant design and supplyFrac sand plants

2010

Technical resources

Outotecs test facilities house our full range of gravity, magnetic and electrostatic equipment enabling both laboratory and pilot-scale studies for frac sand plant design.

Industry know-howMore than just how to process, we know market requirements:

The American Petroleum Institute (API) setsdemanding specifications for silica sands to be used in hydraulic fracturing (frac sands).

We provide successful operations by ensuring products are to spec.

Acceptable frac sandIt must be round grain It must withstand tremendous pressures and not breakdown

Older deposits are generallymore pure and thus stronger.

It must be relatively coarse

The primary frac sand requirements are 90wt% -20 +40 mesh (-850 +425m). Some specifications dictate that 90wt% be between designated sizes such as: -12 +20 mesh (-1600 m +850 m) -40 +70 mesh (-425 +212m) -70 +140 mesh. (-212 m +104 m)

Why such stringent specifications?Frac sands are used as a proppant, or Sized particles mixed with fracturing fluid to hold fractures open after a hydraulic fracturing treatment Hydrofracing is the forcing of a concoction of frac sands, viscous gel and other chemicals down a well to prop open fractures in the subsurface rocks thus create a passageway for fluid from the reservoir to the well. If the grains are not strong enough or are not the right size, they wont effectively prop open the passageways

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Outotec frac sand process offerings

Outotecs applicable technologiesOutotecs line of physical separation equipment: Floatex Attrition Scrubber Floatex Density Separator Outotec Spirals Outotec Rare-Earth Roll Magnetic Separators Solid liquid separation: Outotec thickeners Outotec Larox filters The entire process can be automated with Outotecs Intelligent Instruments: Analyzers and automation Limited use equipment Outotec Rare-Earth Drum Magnetic SeparatorsFloatex is a trademark of Floatex Separations Ltd (UK)

Wet and dry flowsheetWet processingReduce turbidity by washing away any clay slimes or other fines. Break up agglomerates Preliminary sizing to remove unnecessary undersized material while still wet and water extraction when needed Reduce down streamprocessing costs

Dry processingSize sand into various frac sand products Remove any magnetic minerals which are generally too soft Remove any non-quartz minerals that affect crush and acid solubility requirements set forth by API

Comprehensive frac sand flowsheet

WashingSimplest/lowest cost for cleaning frac sand Sometimes all that is needed Process: Water added to sand Pumped to cyclone for desliming Movement is sufficient to loosen clays which canthen be removed in a variety of ways

.Unfortunately, most of the time more is needed

ScrubbingUsed when clay/silts are tightly bound to silica, or when larger clumped balls of clay are present Scrubbing breaks down the clusters to allow concentration of silica grains down stream Scrub times, number of units and proper positions in flowsheets are all determined during the testing phase of flowheet development.

CyclonesRemove 100m (-140 mesh) material below 23 wt% Effective for removing 80-90% of slimes Extra stages can improve rejects Low cost but underflow contains high water

Hydraulic classifiersMore efficient than cyclones Remove 150m (-100 mesh) material above 45 wt% Consistently lower level of fines Also used for pre-sizing Improves efficiency of dry Sometimes used with a cyclone for best plant performance

plant Allows for market flexibility

Thickeners

Remove solids from slurry (improve clarity) Retrieve water for re-use in plant Limit requirement for slurry transport and disposal

Heavy mineral rejectionRemove free iron bearing minerals If high percentage of impurities are present as inclusions, i.e. not liberated from the silica, spirals will not be effective Magnetic separationwould be implemented to reject these grains.

Filters

Remove moisture before drying to reduce costs Key for colder or high humidity climates Secondary role of water retrieval for re-use within the plant

Fluid Bed DryersSilica sand products are generally sold dry Normally performed on fluidised bed dryers More fuel-efficientthan rotary dryers of the past

Product SizingCrucial step Ensure product meets minimum 90 wt% of a particular product Require advanced screeners High throughput Precise sizing Ensure high recovery Trailing or polishing screens can scavenge for misplaced products

Magnetic SeparationUsed when excess levels of non-quartz minerals are present

Critical to remove as they tend to be softer and more acid soluble If not products can fail API tests High throughput Precise separation Low energy consumption More accurate and less costly than flotation

Rare-earth magnets

Frac sand plant process solutionsMineralogical testwork Bulk sampling and processing Flowsheet development Engineering Management of the procurement and construction of turnkey operations.

Reference operation: USA 2008Application: Frac Sands

Scope:

Flowsheet development, circuit design, turnkey plant supply and circuit upgrade

Capacity:

1000 TPH

Reference operation: USA 2006Application: Frac Sands

Scope:

Complete turnkey plant, engineering, procurement and construction.

Capacity:

200 TPH

Reference operation: Jordan 2005Glass Sand, Frac Application: Sand & Ground Silica

Scope:

Complete turnkey plant, engineering, procurement and construction.

Capacity:

80 TPH