PROTON®: The World’s Most Powerful Membrane Antiscalant Software
Why was AWC’s 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.
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 manufacturer’s 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 Desalitech’s 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, Proton’s 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.
- 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.
- Silica Polymerization Kinetics Index (SPKI): The SPKI is the only index that considers both the thermodynamic and kinetic properties of silica to predict membrane scaling. The rate of silica scale formation is essential in predicting how it will impact the membrane system’s operation. 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 is most soluble at higher temperature, but paradoxically, its rate of polymerization is also faster with increasing temperature. The SPKI accounts for all these competing mechanisms, allowing the user to determine the highest recovery at which silica scaling can be inhibited.
- CaSiO3 Index: This index predicts formation of calcium silicate at high pH conditions. AWC® experimental work has shown that calcium silicate formation can trigger heavy silica scaling, meaning that its inhibition is essential to silica scale control. This index is calculated based on thermodynamic properties that consider for pH, temperature, ion complexes and ion activity, but additionally corrects for temperature based on kinetics of nucleation. By predicting the conditions at which CaSiO3 will nucleate, maximum recovery and maximum operating pH can better be predicted for any water quality.
- CaSi2O4 Index: This index predicts formation of calcium silicate at neutral pH conditions. AWC® experimental work has shown that any nucleation of CaSi2O4 crystals can trigger severe silica scaling, and its inhibition is therefore essential to silica scale control. This index is calculated based on thermodynamic properties that consider for pH, temperature, ion complexes and ion activity, but additionally corrects for temperature based on kinetics of nucleation. By predicting the conditions at which CaSi2O4 will nucleate, maximum recovery and maximum operating pH can better be predicted for any water quality.
What is the Chemical Speciation function in PROTON®?
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 into PROTON® 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 user’s information without explicit permission from the user.