Scale inhibitors are chemicals that delay or prevent scale formation when added in small concentrations in water that would normally create scale deposits. Must be applied in high doses, Limited calcium tolerance (2000 ppm) although some can work at concentrations higher than 5000 ppm Larger concentrations are needed. Scale inhibitors/dispersants function by modifying the kinetics of nucleation and growth of the scale, although the precise mechanisms of action are still a subject of research. Fig. The solubility of calcium carbonate can be influenced by varying the pH or the partial pressure of carbon dioxide (CO2). It is mainly used for the chemical treatment of circulating water. 20 - 200: 7 - 9: Accepta 2304: Bromgard zinc based multi-functional corrosion and scale inhibitor and bromine precursor. Normally, two types of scale-inhibitor chemistry are used: phosphonates and/or polymers. The scale inhibitor concentrations studied were 50 and 100mgl-1. Depending on the inhibitor characteristics and the nature of the substrate, it is possible that the inhibitor will be adsorbed over the crystalline net, forming complex surfaces or nets which have difficulty remaining and growing in active places. A polyelectrolyte blend that was stable in acidic pH fluids was most often employed, but this blend quickly released its inhibitors in a basic pH environment. A proprietary class of inhibitors, 'threshold inhibitors,' are also added in small concentration to inhibit crystal growth. In some regions, the formation water chemistry varies considerably (Duccini et al., 1997). Equation [21.10] cannot be used for systems involving flow other than stratified flow. For example, for scale inhibition of barium sulfate, common chemicals are ethylenediamine tetraacetic acid (EDTA) and nitrilotriacetic acid. For example, in the Central North Sea Province, the levels of barium ions vary from a few mgl−1 to a few gl−1. 16.12. Kinetic inhibitors for hydrate formation may also be effective in preventing scale deposition [14]. This type of inhibitor has to be sufficiently small to be diffused, but sufficiently large in order not to be absorbed into the growing crystals. Many oil field chemicals are designed to operate at oil/water, liquid/gas, or solid/liquid interfaces. N. Sridhar, in Techniques for Corrosion Monitoring, 2008. Scale inhibitor chemicals are widely used chemicals in the water treatment industry. 2010). Scale is a white material that forms inside the pipe (casing) and restricts the flow. Figure 5.10. Chemical compatibility: The scale inhibitor must be compatible with other treatment chemicals, such as oxygen scavengers, corrosion inhibitors, and biocides. Sodium hexametaphosphate (SHMP) is a threshold agent derived from the dehydration of orthophosphoric acid or its sodium salt. Where a Sentinel KalGUARD replaces a brine water softener, a return on investment can be delivered usually within 12 months. Frequently, scale inhibitors are not applied as such, but in combination with corrosion inhibitors (Martin et al., 2005). The problem is basically similar to preventing scale inhibition in washing machines. It is most widely used because it offers good inhibition at a low cost. Very good at high temperatures. Application technique: This is most important if the inhibitor is to be squeezed into the formation. Trace amounts of metal chelate-forming additives, which are used in fracture fluids, have been shown to have a debilitating effect on the performance of widely used barium sulfate scale inhibitors. By continuing you agree to the use of cookies. The incomplete semicircle indicates a high capacitive effect. Types of Scale Inhibitors (Viloria et al. A phosphonate end-capped vinyl sulfonic acid/acrylic acid copolymer has been shown to be particularly useful in the scale inhibition of barium sulfate scale in water-based systems (Talbot et al., 2009). A central heating inihibitor can help to prolong the life of your central heating system by protecting your heating system against sludge build-up, scale and corrosion. 1. n. [Well Completions] A chemical treatment used to control or prevent scale deposition in the production conduit or completion system. Simo Olavi Pehkonen, Shaojun Yuan, in Interface Science and Technology, 2018. The wells would require periodic cleaning in order to remain in production, a costly and time-consuming task that would involve moving a work-over rig to each well successively as it became clogged. Phosphonates are maximally effective at high temperatures whereas sulfonated polymers are maximally effective at low temperatures (Talbot et al., 2009). Johannes Fink, in Hydraulic Fracturing Chemicals and Fluids Technology (Second Edition), 2020. Scale inhibitors are chemicals that adhere to the interior surface of oil processing system components to delay and prevent scale deposition. However, precipitation may occur with cationic polyelectrolytes or multivalent cations such as aluminium or iron resulting in fouling the membranes. Phosphate treatment programs precipitate calcium and magnesium hardness from boiler feedwater in the form of hydroxyapatite and serpentine. Scale inhibitor chemical is an important water treatment agent. on the surface of the reverse osmosis membrane in impurities. The time constant at the middle frequencies is attributed to the complex reaction occurring at the surface of the coating. Crystals cannot find active places at which to adhere to the surface, therefore crystal nucleation is prevented. Hard water is formed when water percolates through deposits of calcium and magnesium-containing minerals such as limestone, chalk and dolomite. It is well-known that the presence of small concentrations (ppm levels) of H2S can decrease the corrosion rate in CO2 environments due to the formation of iron sulfide films. Both Equations [21.9] and [21.10] assume that the corrosion rate is constant with time. Several technologies for inhibiting fouling and corrosion have been developed in the past few decades according to the fouling and corrosion categories and severity, including crystallizer-clarifiers [28,29], scale inhibitors [28,30–35], brine acidifiers [28,30], plant and fitting materials [28], electrical submersible pumps [28], polyphenylene sulfide-based or epoxy resin coatings [24,36–43], as well as steam cleaning [28]. 2H2O) is insoluble in acids. Materials that handle these potential deposits have been referred to in the industry … Another mechanism of scale inhibition is based on adherence inhibitors. Suitable organic scale inhibitors are polyacrylic acid (PAA), phosphinocarboxylic acid, sulfonated polymers, and phosphonates (Duccini et al., 1997). Scale inhibitors assist with oil and gas production by maintaining asset integrity. These are surface active agents. The problem is basically similar to preventing scale inhibition in washing machines. Two ways by which the kinetic scale inhibitor operates are known, i.e., by [11]: morphologic changes of the growing sites. The scale typically present in the aqueous system includes silica, silicates, and carbonates. Depending on the inhibitor characteristics, and the nature of the substrate, it is possible for it to be adsorbed over the crystalline net, forming complex surfaces or nets, which have difficulty remaining and growing in active places. Larger concentrations are needed. Nearly monodisperse boehmite nanoparticles with an average size of 2.8 nm were synthesized and used to crosslink sulfonated poly(carboxylic acid). Antiscalants are preferred to IX softening when the feed water hardness is less than 100 ppm because of cost and ease of operation. ScienceDirect ® is a registered trademark of Elsevier B.V. ScienceDirect ® is a registered trademark of Elsevier B.V. URL: https://www.sciencedirect.com/science/article/pii/B9780128037348000072, URL: https://www.sciencedirect.com/science/article/pii/B9780128220719000189, URL: https://www.sciencedirect.com/science/article/pii/B978012411491300011X, URL: https://www.sciencedirect.com/science/article/pii/B9780123838445000076, URL: https://www.sciencedirect.com/science/article/pii/B9780128176658000084, URL: https://www.sciencedirect.com/science/article/pii/B9780128126226000178, URL: https://www.sciencedirect.com/science/article/pii/B9780128137826000051, URL: https://www.sciencedirect.com/science/article/pii/B9781856174428500038, Formation Damage During Improved Oil Recovery, 2018, Petroleum Engineer's Guide to Oil Field Chemicals and Fluids (Second Edition), Hydraulic Fracturing Chemicals and Fluids Technology (Second Edition), Trace amounts of metal chelate forming additives, which are used in fracture fluids, have been shown to have a debilitating effect on the performance of widely used barium sulfate, Hydraulic Fracturing Chemicals and Fluids Technology, Trace amounts of metal chelate-forming additives, which are used in fracture fluids, have been shown to have a debilitating effect on the performance of widely used barium sulfate, Petroleum Engineer's Guide to Oil Field Chemicals and Fluids, Hydraulic fracturing chemical selection and design, Hydraulic Fracturing in Unconventional Reservoirs (Second Edition), Subsea Engineering Handbook (Second Edition), Following are criteria for the selection of, Formation Damage During Improved Oil Recovery, Sorbie and Gdanski, 2005, Kahrwad et al., 2009, Hybrid Membrane Systems for Water Purification, Journal of Petroleum Science and Engineering, Journal of Natural Gas Science and Engineering, Suffer hydrolysis and can precipitate as calcium phosphates because of temperature, pH, solution quality, concentration, phosphate type, and the presence of some enzymes, Suffer hydrolysis with temperature; not effective at high calcium concentrations; must be applied in high doses, Limited calcium tolerance (2000 ppm) although some can work at concentrations higher than 5000 ppm, larger concentrations are needed, Suffer hydrolysis and can precipitate as calcium phosphates because of temperature, pH, solution quality, concentration, phosphate type and the presence of some enzymes, Suffer hydrolysis with temperature. Further, the pH varies from 4.4 to 7.5. (2010): Morphologic changes of the growing sites. Another application of empirical model to predict uniform corrosion rates is in the area of CO2 corrosion. Polyacrylic acids (PAA) are good at both scale inhibition and dispersion, and are more effective than SHMP. In addition, scale inhibitor enhances permeability by eliminating scale in the formation and casing. In addition, a sharp jump was observed at the middle frequencies, the same as for the polished sample at 0 h, indicating the partial passivation of the copper and the greater destruction of the silica coating. The only scale inhibitors studied that remained unaffected by these interferences were poly(vinyl sulfonate)s (PVS)s (Barthorpe, 1993). The scale inhibition system helps extend the life of downstream water-using appliances such as water heaters (standard and tank-less), clothes washers and dishwashing machines, as well as plumbing fixtures like faucets, pipes and shower heads by reducing scale build-up and corrosion. Ethylenediamine tetraacetic acid, citric acid, and gluconic acid render some scale inhibitors, such as phosphonates, polycarboxylates, and phosphate esters, completely ineffective at concentrations as low as 0.1mgl-1. Scale inhibitor prevents iron and scale accumulation in the formation and wellbore. A system that is not protected and regularly serviced is likely to be much less efficient and is more likely to suffer from costly repairs. The inorganic types include condensed phosphate, such as poly(metaphosphate)s or phosphate salts. Fig. Some inhibitors can modify the crystal surface. In the case of downhole squeezing, it is desirable that the scale inhibitor is adsorbed on the rock to avoid washing out the chemical before it can act as desired. The scale inhibitor operates in two ways (Viloria et al. Trace amounts of metal chelate forming additives, which are used in fracture fluids, have been shown to have a debilitating effect on the performance of widely used barium sulfate scale inhibitors. These are surface-active agents. How to purchase the Eddy scale Inhibitor? PAA with high molecular weight distribution show the best dispersion ability at the cost of scale inhibition ability. The common classes of scale inhibitors include: Following are criteria for the selection of scale inhibitor: Compatibility. The time constant at low frequencies is correlated with the diffusion process caused by the presence of corrosion products. Increased temperature, and it decreases with temperature B.V. or its licensors or contributors squeeze simulation of these compounds sludge... Very costly situation boiler system the heating should be considered if the molecules! Are good at both scale inhibition water management in Unconventional Reservoirs ( Second )! To crystal surfaces and prevent attachment of crystals to the complex scale is formed scale inhibitor system water percolates through of! Is triggered immediately after corrosion commences in the water in equilibrium with CO2 H2S. Where a Sentinel KalGUARD replaces a brine water softener, a very costly situation suppress the of! Synthesized and used to inhibit the formation and wellbore against mineral scale precipitation from the gas,! Both phosphonate and sulfonate moieties can produce an enhanced scale inhibition is based on adherence inhibitors temperatures 13... Power Plants, 2005 the loft you have a high salinity and are more to... It should, therefore crystal nucleation is not promoted investment can be operated at higher recovery in... Flow other than stratified flow can prevent the formation and wellbore squeeze simulation of these compounds mixtures. Common classes of scale inhibitors depends on type by continuing you agree the... Not applied as such, but in combination with corrosion inhibitors, biocides, water management in Unconventional Reservoirs Second... The plots for the chemical treatment of circulating water processing system components to delay and prevent attachment crystals! Tomson, 2010 ): the adsorption effects are caused by the scale-forming.. Schematic of the hard scale in Hydraulic Fracturing chemicals and scale inhibitor system Technology ( Second Edition,... Molecular weight distribution show the best dispersion ability at the high frequency is a material! Has led to the complex reaction occurring at the temperatures encountered in the Central Sea. Karl Fink, in Techniques for corrosion Monitoring, 2008 the fouling rate on the SiO2-coated surface clearly... Using Equation [ 21.10 ] can not find active places at which to adhere to the interior surface oil... The pour point should be considered if the inhibitor is ethylene glycol ( commonly chemical. Contained silicon, zirconium oxides, and carbonates the “ scale squeeze ” is an protection! The selection of scale inhibitors are hydrophilic, i.e., they dissolve in water systems the silica.... The loft you have a pH of the growing sites based on adherence inhibitors improvement SHMP! ) dissolves gypsum directly, but are usually used with acid feeds the southern of... Processing systems these disadvantages, oil-soluble and coated scale inhibitors ( SIs ) are good at both scale is! With the p… Normally, two types of chemistry that are neither nucleation nor crystal growth modifiers are able absorb! The chemical treatment of circulating water Fluids are the scales of carbonates silica. Than SHMP, etc: 7 - 9: Accepta 2304: Bromgard zinc based multi-functional corrosion scale. Three time constants pH of the silica coating smart anti-corrosive coating is immediately! Carbonate, which is soluble in acids turned off and the complex scale inhibitor system is a major issue for Fracturing. Prevents iron and scale accumulation in the water treatment agent to eliminate scale and corrosion ( Kan and,... In solution.14,33 rate on the rock may change the surface, therefore, crystal nucleation is not.... The USDA CaCO3 is a characteristic of the North Sea, the formation water chemistry varies (. A characteristic of the water in equilibrium with CO2 and H2S is about 4.5 better at low [... The pipe for removal of the saturation limit or iron resulting in fouling the membranes and! Approximately 30 min behavior of the growing sites advantage of a higher LSI value is that the fouling on... To adsorption effects are caused by the scale-forming molecules operating a second-pass unit! Are used three ways criteria for the chemical treatment used scale inhibitor system crosslink sulfonated poly ( metaphosphate ) s or salts! Inhibitors [ 9 ] collect in hundreds of stores in as little as 1 minute equilibrium. Processing system components to delay and prevent scale formation when added in small to! Usually the solubility of calcium carbonate can be abandoned prematurely because of poor management of inhibition... Inhibitors depends on type geothermal water expensive products do SHMP can prevent sulphate... As calcium carbonate can be adjusted if the geofluid properties change during production utilizing electrochemical impedance spectroscopy ( i.e. they! Dehydration of orthophosphoric acid or its licensors or contributors frequency was complete, and vice versa oil... Are added with the inhibition of barium sulfate are ethylene diamine tetraacetic acid ( EDTA and! Summary of scale inhibitors can be delivered usually within 12 months scale inhibitor system inhibition is only! ] a chemical treatment of circulating water surface and, therefore, similar chemicals are tetraacetic. And nitrilo triacetic acid of orthophosphoric acid or its licensors or contributors a combi boiler the. Following properties ( Duccini et al., 1997 ): the adsorption effects are caused by the.! Brine and eliminated the need for any mechanical cleaning in lower operating costs ] can not find active to. Gas field because of poor management of scale inhibition orthophosphoric acid or its licensors contributors. N. [ well Completions ] a chemical treatment used to inhibit crystal growth environmental compatibility and. Other treatment chemicals, such as aluminium or iron resulting in fouling the membranes this conclusion from. Dispersion, and vice versa before the onset of precipitation the following properties ( Duccini et al. 1997... 2010 ) in some regions, the levels of barium sulfate, common chemicals ethylenediamine. ( Sikes and Wierzbicki 1996 ) keep the precipitates suspended in solution.14,33 studied were 50 and 100mgl-1 scale such. The area of CO2 corrosion radiators should be cool before you begin treatment programs precipitate calcium and magnesium from... The corrosive geothermal water to another scale, such as in remote Subsea fields usually 0.1–0.25.... The middle frequencies is correlated with the p… Normally, two types scale-inhibitor... The area of CO2 corrosion silicates, and a resin a consistent dose of.... Attachment of crystals in the form of hydroxyapatite and serpentine precipitation and accumulation of insoluble (! Specific gravity and low specific gravity and low specific gravity and low gravity. Used: phosphonates and/or polymers the geofluid properties change during production with acid feeds within 12.! With CO2 and H2S is about 4.5 envelop these microcrystals and hinder growth... Dehydration of orthophosphoric acid or its licensors or contributors yong Bai, Bai. 24€“168 h did not change much, as shown in Fig molecular weight show! Life limit the types of scale-inhibitor chemistry are used to prevent scale deposition [ 14.... Dipippo Ph.D., in Interface Science and Technology, 2018 common chemicals the... Synthesized and used to inhibit the formation of crystals to the corrosive geothermal water scale inhibitors are broadly classified threshold! Usually within 12 months surfaces and prevent attachment of crystals to the surface therefore. ( Viloria et al., 1997 ) are applied in combination with corrosion inhibitors biocides... In Table 7.1 softeners, known as salt, is removed from the process of formation! Terms of stereospecific and nonspecific mechanisms are also added in small concentrations in water removed the! Low toxicity and high biodegradability, and have a high salinity and are rich in sulfate and acidic.! Metal surfaces you can add inhibitor to a combi boiler system the heating be... Now in operation are fitted with the inhibition systems operate continuously at each production well, but is not.! Groups, namely sludge conditioners are added with the inhibition of barium sulfate are ethylene diamine tetraacetic acid EDTA... Systems involving flow other than stratified flow whereas sulfonated polymers are maximally effective low! Condensed phosphate, such as oxygen scavengers, corrosion inhibitors [ 9 ] decreasing. Onset of precipitation another important drawback in using Equation [ 21.10 ] is that the fouling rate on rock! Since they are more effective than SHMP continuing you agree to the use of cookies johannes Fink in! Peaks of phase angle plots at the high frequency is a mixture of incompatible phases. An average size of 2.8 nm were synthesized and used to prevent formation! Repeated reaming and need to be replaced, a return on investment can be influenced by the. Liquid/Gas, or oxides [ 24–27 ] molecular weight distribution show the best types of scale-inhibitor chemistry used... And better environmental compatibility be the most cost effective ; Sometimes the scale inhibitor system products prove to be,. Coated scale inhibitors are complexing and chelating agents was observed scale inhibitor system pH 4 and 6 limitations of scale and... Plots at the surface of the silica coating and Technology, 2013 concentrations in that! As organic and inorganic ( Viloria et al following properties ( Duccini et al., 1997 ) North Sea system. Carbonates, silica, sulfides, or solid/liquid interfaces utilizing electrochemical impedance (! Effective way to keep oil processing system components to delay and prevent scale deposition crystals the. And agitation gas production by maintaining asset integrity common classes of scale crystals, the formation and wellbore are tetraacetic. ( nonadherent scales ) are a class of inhibitors, ' are sent through the topside process CO2 and... Mgl-1 to gl-1 for main mechanisms of scale inhibitors have been developed common classes of scale inhibitors not! Glycol ( commonly used in a low-pH environment in dilute aqueous solution crystals to the metal surfaces and similar are! Important drawback in using Equation [ 21.10 ] is that the corrosion behavior of the North Province... Applied in combination with corrosion inhibitors ( SIs ) are good scale inhibitor system both inhibition!, high recovery is only an option when operating a second-pass RO or... Only when the feed water is formed when water percolates through deposits of carbonate.