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Membrane Antiscalant

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For over 20 years, we have applied our unique understanding of water chemistry to help resolve complex operational issues, and improve membrane pretreatment processes. AWC® has become renowned as one of the most trusted suppliers of membrane chemicals for Reverse Osmosis/Nanofiltration (NF/UF) and Microfiltration/Ultrafiltration (MF/UF) systems. – PowerPoint PPT presentation

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Title: Membrane Antiscalant


1
Proton Antiscalant Software
membranechemicals.com/en/services/proton-antiscala
nt-software/
PROTON The Worlds Most Powerful Membrane
Antiscalant Software Why was AWCs new
antiscalant software named PROTON? Protonation
is the acceptance of acid protons from the
surrounding solution, while deprotonation is the
donation of acid protons to the surrounding
solution. The name PROTON was selected because
all the calculations in the software, whether for
scale saturation, or for salt rejection, are
based on protonation and deprotonation of weak
acids, bases and ion complexes in the Reverse
Osmosis/Nanofiltration (RO/NF) process. How can
PROTON help me with system design? PROTON
allows the user to compare the required feed
pressure and permeate water quality for various
membranes under identical conditions. Once the
design is selected, the user can simply select a
different membrane type, and can instantly see
the impact on pressure, water quality and
scaling potential. The user can see real time
impacts of changes in pH, temperature or
recovery on pressure, flux and permeate
quality. PROTON accurately calculates boron
rejection with varying pH, accounting for both
temperature and ionic strength, and
differentiating between rejection by
nanofiltration, brackish, and seawater
membranes. Other contaminant rejections that are
calculated include iron, manganese, aluminum,
ammonia, nitrate, nitrite, sulfides. It is also
the only software currently available that
predicts arsenic rejection with varying pH,
temperature and ionic strength. PROTON even
provides calculations that help with design of
pretreatment coagulation and post treatment
degasification (see below Chemical
Speciation). What makes PROTON different from
other antiscalant software? Most reverse osmosis
and nanofiltration antiscalant software assume
100 salt rejection. The few that allow entry of
the membrane salt rejection apply it as a factor,
completely ignoring the fact that salt passage
is a function of membrane flux.
2
  • PROTON is the first antiscalant software that
    can design a nanofiltration or reverse osmosis
    system, and account for membrane properties and
    flux rates at the various stages of a system.
    The user has the option of using the system
    design provided by PROTON, or overwriting it
    with the membrane manufacturers array and flow
    rates per stage. The software also calculates
    the concentration polarization factor, providing
    the user with the most accurate, and optimum
    scale inhibitor dosages required for NF, RO or
    NF/RO hybrid systems. The hybridization feature
    allows the user to enter any combination of
    membranes within the same stage. PROTON is also
    the only antiscalant projection software capable
    of modelling Desalitechs Closed Circuit Reverse
    Osmosis (CCRO) technology. CCRO is a unique
    technology that uncouples recovery, flux and
    crossflow to enable operation at recoveries well
    beyond those achievable with conventional RO.
  • PROTON calculates the scaling potential for over
    50 different scales that can form in RO/NF
    membrane systems. Many RO antiscalant software
    programs use canned formulas that fail or give
    erroneous readings outside a certain pH or TDS
    range. However, Protons scaling calculations
    are not based on formulas but rather on
    thermodynamic data acquired from peer reviewed
    scientific research papers. Temperature, ion
    activity, and ion complexes are considered for
    every single calculation. The software accounts
    for over 130 ion complexes, allowing accurate
    modelling for complex industrial wastewater reuse
    or seawater at the entire RO operating range of
    1 11. The scaling saturations calculated by
    PROTON are therefore the most accurate and
    reliable in the industry with all reactions
    tested in a controlled environment and reconciled
    in real world applications.
  • PROTON has also introduced five powerful new
    indices
  • Calcium Carbonate Nucleation Index (CCNI) The
    CCNI is a calcium carbonate index that accounts
    for pH, temperature, ionic activity, and ion
    complex formation. In reverse osmosis and
    nanofiltration systems, any amount of calcium
    carbonate scale will impact performance. The
    commonly used Langelier Saturation Index (LSI) is
    limited in that it does not account for ion
    complex formation, and only estimates ionic
    activity by applying a fudge factor based on
    TDS. At higher TDS, the Stiff Davis index is
    often used, but is very unreliable when used for
    non-seawater applications. The Calcium Carbonate
    Precipitation Potential (CCPP) calculates the
    actual quantity of scale that can precipitate.
    But it is stoichiometrically limited, so that a
    higher driving force for scale formation can be
    masked by a low calcium concentration a water
    with a high driving force for scale formation and
    a non-scaling water can both have a CCPP of only
    125 mg/l simply because the calcium concentration
    is only 50 ppm in both. The CCNI is able to
    accurately predict spontaneous nucleation and
    saturation of calcium carbonate for any water
    quality in the pH range of 1 11 and
    temperature range of 5 60 C.
  • Malki Kinetics Index (MKI) This is an index
    based on the rate of formation for calcium
    carbonate that is used to calculate antiscalant
    dosages. In reverse osmosis and nanofiltration
    systems, even a very thin layer of calcium
    carbonate scale will impact performance. Most
    antiscalant projection software rely on the
    Langelier Saturation Index (LSI) or the Calcium
    Carbonate Precipitation Potential (CCPP) which
    quantify how much scale will form. That quantity
    of scale could form in seconds or over a period
    of several days, and this has made these two
    methods

3
  • inadequate for reliably calculating the most
    optimal dosage of RO/NF antiscalant. The key is
    to determine whether formation is slow enough to
    be controllable by antiscalant, and if it is,
    then an exact dosage can be determined to
    redissolved crystal nuclei at a faster rate than
    they form.
  • Antiscalant Precipitation Index (API) This index
    is the first of its kind in determining the
    limitations of various antiscalants in a membrane
    system. All scale inhibitors have the tendency
    to form calcium or magnesium scales. This applies
    to phosphonate, acrylate, and even green
    antiscalants. AWC has also identified complex
    calcium-carbonate-antiscalant salts that form
    under certain conditions. The API calculates the
    solubility of antiscalants based on the amount of
    calcium in the water, alkalinity, pH, ionic
    strength, ion complexes, and temperature. It
    accounts for the different solubilities of
    different antiscalant salts, and accurately
    predicts whether a given dosage will result in
    antiscalant salt precipitation. Those who have
    been in the membrane industry long enough will
    recognize cases where scaling has occurred even
    when the calcium carbonate saturation was
    relatively low. This occurs because of
    precipitation of calcium-antiscalant salts when
    the active inhibitor is lost, mineral scaling
    will form. The API allows the user to predict the
    likelihood of this type of scaling and
    accordingly make adjustments while still in the
    design phase.
  • Malki Phosphate Index (MPI) This is the only
    calcium phosphate saturation index that accounts
    for pH, temperature, ion complexes and ionic
    strength. Because calcium phosphate has such low
    solubility, its saturation can be directly
    correlated to its rate of formation. The MPI
    accurately determines whether calcium phosphate
    scaling will occur, and allows for antiscalant
    selection and dosage calculation for its
    inhibition.
  • Malki Silica Index (MSI) Silica formation can be
    slow enough so that a silica saturated solution
    may not precipitate until well after it has left
    the membrane system. The rate of formation is
    therefore essential in predicting how silica will
    impact the membrane systems operation. Silica
    polymerizes into colloidal particles that grow
    and/or agglomerate to form silica scale. Certain
    cations such as calcium and magnesium can make
    silica less soluble and increase its rate of
    polymerization. Silica is more soluble at higher
    pH, but AWC studies have shown that higher pH
    also increases the rate of polymerization at high
    ionic strength. Silica solubility increases at
    higher temperature, but paradoxically, its rate
    of polymerization is also faster with increasing
    temperature. The MSI accounts for all these
    competing mechanisms, and provides the most
    accurate prediction tool in the industry. Most
    antiscalant projection software calculate maximum
    recovery by assuming that a concentration of up
    to 300 ppm silica can be controlled by
    antiscalants this overly simplistic approach is
    never reliable. By contrast, the MSI uses a
    highly sophisticated algorithm to account for
    all the thermodynamic and kinetic properties of
    silica so as to predict the behavior of silica
    in the system. The MSI can reliably estimate the
  • amount of time that silica scaling will cause a
    10 15 decline in permeability this is
    extremely useful when performing cost analysis,
    allowing the designer to compare the cost of
    cleaning vs the cost of brine disposal while
    operating at a lower recovery.
  • What is the Chemical Speciation function in
    PROTON?

4
  • PROTON speciates weak acids, weak bases, metal
    hydroxides, and ion complexes based on pH, ionic
    strength, oxidation state, and temperature. This
    allows the user to determine the number of
    charges that the compounds will carry under any
    given set of conditions. This is essential for
    predicting both scale formation and front end
    membrane fouling by metal hydroxides. The
    speciation function also allows the user to see
    changes in the charges of any species with
    changes in temperature or pH in real time a
    function that is extremely useful in optimizing
    pH for upstream coagulation. Finally, it allows
    the user to design for post treatment
    degasification based on carbon dioxide, ammonia,
    and/or hydrogen sulfide in the permeate.
  • Why is PROTON only available as a cloud based
    software? PROTON is cloud based for three
    primary reasons
  • It can be accessible from any computer, tablet or
    smartphone that has an internet connection.
  • Updates and improvements to the software can be
    performed seamlessly without the need for the
    user to download an update.
  • Cloud based software can be constantly monitored
    for functionality, and eliminates issues
    associated with computer operating systems that
    are constantly changing from one year to the
    next.
  • How can I be assured that information that I
    enter intoPROTON will remain confidential, and
    not violate any non-disclosure agreements I may
    have?
  • PROTON is based on a highly secure server with
    multiple layers of security. Furthermore, it
    does not allow any user to sign in without
    agreeing to the terms and conditions of use,
    which include a non-disclosure agreement (NDA)
    between the user and American Water Chemicals,
    Inc. This NDA provides the user with assurance
    that American Water Chemicals will be bound by
    confidentiality and will not share any of the
    users information without explicit permission
    from the user.
  • Back to Solutions Page
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