METHOD AND SYSTEM FOR CONTROLLING CORROSION INHIBITOR FEED

Description

This non-provisional application claims the benefit of U.S. Provisional Application No. 63/687,880, filed Aug. 28, 2024.

BACKGROUND

Corrosion in industrial water systems is a serious problem. It causes undesirable consequences, including loss of heat transfer, increased cleaning frequency, equipment repairs and replacements, shutdowns, environmental problems, and increasing resources and costs associated with each.

Treatment of corrosion in water systems is typically achieved by the application of various corrosion inhibitors in the water including, for example, phosphates, polymers, chromates, tin, zinc, molybdates, nitrites, and combinations thereof. However, in a water system, parameters may constantly vary, such as pH, temperature, flow velocity, and concentrations of various ions, compounds, or elements within the water system. Each of these parameters may affect the amount of corrosion within the water system. Thus, an amount of treatment to be added to a water system may be difficult to determine.

Too little corrosion inhibitor introduced into a water system may not effectively address the corrosion. On the other hand, too much corrosion inhibitor introduced into a water system may result in unnecessary costs and waste. Accordingly, there is a need for a system and method to treat a water system with an optimal amount of corrosion inhibitor.

SUMMARY

According to some embodiments, it is possible to automate dosage concentrations of corrosion inhibitor systems using a calcium phosphate index and at least one other parameter. An objective is to ensure, for example, an optimal amount of corrosion inhibitor in a process stream in ever-changing environments to minimize corrosion, fouling, and scaling. For example, improved corrosion inhibition can be achieved at lower cost and with less environmental impact by feeding corrosion inhibitors in an optimized manner.

According to one aspect, the disclosure provides a method for applying a corrosion inhibitor composition to a water stream in a water system, the method comprising: determining a calcium phosphate saturation index of the water stream; determining at least one other parameter of the water stream; determining a dosage of the corrosion inhibitor composition based on a relationship between: (i) the dosage and (ii) the calcium phosphate saturation index and the at least one other parameter; and controlling administration of the corrosion inhibitor composition to the water stream based on the determined dosage.

According to another aspect, the disclosure provides a water system comprising: at least one conduit through which a water stream flows; an injection apparatus configured to inject corrosion inhibitor into the water stream, and one or more processors configured to: determine a calcium phosphate saturation index of the water stream; determine at least one other parameter of the water stream; determine a dosage of a corrosion inhibitor composition based on a relationship between: (i) the dosage and (ii) the calcium phosphate saturation index and the at least one other parameter; and send control signals to the injection apparatus to administer the determined dosage of corrosion inhibitor composition to the water stream.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an industrial water cooling system;

FIG. 2 is a schematic view of an alternate embodiment of an industrial water cooling system; and

FIG. 3 is a graph of a corrosion inhibitor dosage model function of CSPR and CASMR versus dosage curves for a corrosion inhibitor in water systems.

DETAILED DESCRIPTION OF EMBODIMENTS

In the following description, numerous details are set forth to provide an understanding of the present disclosure. However, it may be understood by those skilled in the art that the methods and systems of the present disclosure may be practiced without these details and that numerous variations or modifications from the described embodiments may be possible.

Disclosed embodiments will now be described with respect to exemplary embodiments of industrial processing systems, including water systems. It will be understood that it is not intended for this disclosure to be limited to these specific embodiments.

As used herein, water, water stream, and water supply, for example as used in a water system, are not particularly limited and may include, for example, any aqueous solution comprising at least 50%, 75%, 90%, 95% or 99% water.

Water System

FIG. 1 depicts an embodiment of a cooling water treatment system 100. A sump 22 is in direct, fluid communication with an atmospheric cooling tower 28. A water stream enters the atmospheric cooling tower 28 from the sump 22. After being cooled in the atmospheric cooling tower 28, the process stream may then re-enter the sump 22. As air passes through the atmospheric cooling tower 28, it induces evaporation 38.

Embodiments of the disclosure are not limited to atmospheric cooling towers and may include, for example, any industrial processing system such as water distribution systems, boilers, pasteurizers, water and brine carrying pipelines, storage tanks, reverse osmosis processes, and once-through cooling systems.

At least one conduit including a makeup stream 32 or a feedwater stream may periodically replenish the sump 22. In some embodiments, the makeup stream 32 may be a feed supply, for example, from a body of water. In some embodiments, the makeup stream 32 is configured to continuously feed water to the sump 22. In some embodiments, the makeup stream 32 is configured to feed water to the sump 22 in intervals, for example, when activated by a valve.

A corrosion inhibitor feed supply 12 provides a corrosion inhibitor treatment to the makeup stream 32 to suppress corrosion in the water system 100. In some embodiments, the makeup stream 32 may already include a corrosion inhibitor treatment or components thereof. The method and manner by which a corrosion inhibitor treatment is infused or injected into the makeup stream 32 is not particularly limited. Methods for infusing the corrosion inhibitor treatment, including controlling the flow of the infusion, may include a multi-valve system or the like, as would be understood by one of ordinary skill in the art.

A control system 10 or a controller supplies the corrosion inhibitor into the cooling water treatment system 100 from the corrosion inhibitor feed supply 12. The control system 10 may measure or determine parameters of the cooling water treatment system 100 and determine an amount of corrosion inhibitor treatment or a corrosion inhibitor treatment dosage to provide to the cooling water treatment system 100. The control system 10 or the corrosion inhibitor feed supply 12 may include an injection apparatus or a supply pump and may dose the makeup stream 32 with the determined amount of corrosion inhibitor treatment provided from the corrosion inhibitor feed supply 12 at an injection site.

Fluid from the sump 22 may be discharged along a discharge stream 30, for example, as blowdown. At least one conduit including a discharge stream 30 may be positioned on the sump 22. The discharge stream 30 may be a blowdown or a bleed stream, for example, configured to release excess corrosion inhibitor accumulated in the cooling water treatment system 100, for example in the sump 22. The discharge stream 30 may be released into, for example, an effluent stream.

FIG. 2 depicts an alternate embodiment of a water treatment system 200 including a heat exchanger 26. A process stream is fed along a flow path 20 from the sump 22, where the cooling water is stored. The flow path 20 is pumped through the heat exchanger 26 by a pump 24 and then enters the atmospheric cooling tower 28. The heat exchanger 26 includes a cool water stream 34 and a hot water stream 36. After being cooled in the atmospheric cooling tower 28, the process stream may then re-enter the sump 22.

In FIG. 2, the control system 10 and corrosion inhibitor feed supply 12 are positioned to feed the corrosion inhibitor into the makeup stream 32. However, the positioning of the control system 10 and/or the corrosion inhibitor feed supply 12 is not particularly limited. For example, the control system 10 and corrosion inhibitor feed supply 12 may feed the corrosion inhibitor treatment directly into the flow path 20, before or after the heat exchanger 26.

In FIG. 2, the at least one conduit including the discharge stream 30 is positioned on the sump 22. However, the positioning of the at least one conduit including the discharge stream 30 is not particularly limited. In some embodiments, the discharge stream 30 may be positioned on the flow path 20, for example before or after the heat exchanger 26.

Chemical Feed Automation and Control

Using methods described herein, treatment of the water system 100 is controlled, i.e., adjusted and optimized using a calcium phosphate saturation index and at least one other parameter to, for example, increase overall efficiency and reduce costs. According to an embodiment, the treatment, for example application of a corrosion inhibitor composition into a water stream in a water system, can be precisely and accurately controlled. In some embodiments, the application may be controlled via the control system 10 by sending control signals to an injection apparatus on the corrosion inhibitor feed supply 12. For example, the control system 10 may control a rate of application of corrosion inhibitor into the water system 100 and/or an amount into the water system 100.

Calcium Phosphate Saturation Index and Other Parameters

A calcium phosphate saturation index (CPSI) represents a degree of saturation of a water stream with respect to calcium phosphate. CPSI calculations were developed to predict whether or not a water stream has a corrosion tendency or scaling.

The CPSI may be determined based on calcium and phosphate concentrations and the activity coefficient of these components.

The calcium concentration and/or the phosphate concentration may be a molar concentration, for example, in mol/L. For example, the calcium concentration may be an amount of hardness, Ca, or CaCO₃ per L in the water system 100, and the phosphate concentration may be an amount of PO₄ per L in the water system 100.

A solubility equilibrium constant, K_sp, may be a solubility constant of a material under ideal conditions, which is a product of molar concentrations of individual salts. An ion activity product, IAP, may be a solubility product with the inclusion of activity coefficients. An Activities, α, may be a product of the molar concentration and an activity coefficient. The activity coefficients, γ, may be a thermodynamic variable that accounts for deviations from ideal conditions. Various models may be utilized to calculate this coefficient, for example, such as the Debye-Hückel, Treusdell-Jones, and Pitzer Equations. The CPSI may be a logbase10 of a saturation ratio. Examples of the above describes constants and equations may be as follows:

K sp = [ Ca ] 3 [ PO 4 ] 2 IAP = [ γ Ca * Ca ] 3 [ γ PO 4 * PO 4 ] 2 = [ α Ca ] 3 [ α PO 4 ] 2 Saturation ⁢ Ratio = IAP / K sp CPSI = log 10 ( Saturation ⁢ Ratio )

In some embodiments, a saturation ratio of greater than 1 is indicative of scaling. A saturation ratio of equal 1 is indicative of the system being at equilibrium, and a saturation ratio of less than 1 is indicative that no scaling will occur.

These parameters can be parameters of the water system 100 or its surrounding environment, such as a parameter of an outside water source which feeds the makeup stream 32. The parameters may include parameters of a particular aspect of a water system, such as parameters of the makeup stream 32, the flow path 20, the discharge stream 30, the atmospheric cooling tower 28, the sump 22, or a combination thereof. The parameters may be measured with sensors in real time (e.g., including probes). In some embodiments, the parameters may be known, measured, calculated, or determined. The parameters of the water stream may be measured continuously. Alternatively, the parameters may be measured in intervals, for example, weekly, daily, hourly, or even more frequently.

The sensors may be in communication with the control system 10. The parameters for determining the CPSI may be supplied to the control system 10 by the sensors. The control system 10 may then calculate or determine the CPSI based on the parameters.

At least one other parameter may be evaluated in conjunction with the CPSI to determine and/or adjust the treatment dosage of the corrosion inhibitor.

The at least one other parameter may include but is not limited to at least one of: temperature, pH, flow velocity, alkalinity, a chloride concentration, and a sulfate concentration.

The temperature may be in ° C. The flow velocity may be m/s. Alkalinity may be represented by [MAlk], representing a total alkalinity in a makeup stream. A sulfate concentration may be represented by [SO₄²⁻], and a chloride concentration may be represented by [Cl⁻].

The sulfate concentration and/or the chloride concentration may be a molar concentration, for example, in mol/L. For example, the sulfate concentration may be an amount of SO₄²⁻ per L in the water system 100, and the chloride concentration may be an amount of Cl⁻ per L in the water system 100. The alkalinity may be determined by, for example, a concentration of carbonate HCO₃⁻ and/or a concentration of bicarbonate CO₃²⁻ in the water system 100. The concentration may be in a molar concentration, for example, in mol/L.

In some embodiments, the CPSI may include or be used in conjunction with only one other parameter. Alternatively, the CPSI may include or be used in conjunction with a plurality of parameters, such as from 2 to 8 or from 3 to 5 other parameters.

For example, in some embodiments, the saturation ratio may be multiplied by alkalinity/((X×a sulfate concentration)+a chloride concentration) where X is the weighted coefficient. As shown in the formula above, the concentration of sulfates in the formula may be weighted, for example, by a coefficient in the range of 1 to 6; 1.5 to 4; or 2 to 3. As such, the coefficient may be adjusted so as to not multiply by zero or a negative value. The coefficient may be determined by experimental or theoretical models.

The at least one other parameter can be a parameter of the water system 100 or its surrounding environment, such as a parameter of an outside water source which feeds the makeup stream 32. The at least one other parameter may include a parameter of a particular aspect of a water system, such as a parameter of the makeup stream 32, the flow path 20, the discharge stream 30, the atmospheric cooling tower 28, the sump 22, or a combination thereof. The at least one other parameter may be measured with sensors in real time (e.g., including probes). In some embodiments, the at least one other parameter may be known, measured, calculated, or determined. The at least one other parameter of the water stream may be measured continuously. Alternatively, the at least one other parameter may be measured in intervals, for example, weekly, daily, hourly, or even more frequently.

The at least one other parameter may be added to or subtracted from the determined CSPI to determine a treatment dosage of the corrosion inhibitor to apply to the water system 100. In some embodiments, the at least one other parameter may be weighted with a coefficient. The weighted coefficient may be determined by, for example, theoretical or empirical data and a determined weighted coefficient may vary for each of the at least one other parameters. For example, experimental data may indicate that temperature may have a low impact on the amount of treatment dosage of the corrosion inhibitor required to adequately treat a specific water system and a weighted coefficient of the temperature may be zero or near zero. Alternatively, experimental data may indicate a flow velocity may greatly affect the amount of treatment dosage of the corrosion inhibitor required to adequately treat a specific water system, and a weighted coefficient of such a parameter may be relatively high.

In some embodiments, the at least one other parameter may multiplied with the determined CSPI or the saturation ratio to determine a treatment dosage of the corrosion inhibitor to apply to the water system 100. A weighted coefficient may similarly be applied to the at least one parameter when multiplying with the CPSI or the saturation ratio. For example, in some embodiments, a temperature may be multiplied with a weighted coefficient and the determined CPSI to determine an amount of treatment dosage to apply to the water system 100.

The at least one other parameter may be adjusted or manipulated, for example, with respect to theoretical or empirical data. For example, any number of the at least one other additional parameters may added to a model to adjust a determined amount of corrosion inhibitor to apply to a system. In addition or alternatively, variables within the model, such as weighted coefficients, may be adjusted.

The determined CPSI and the at least one other parameter may be correlated with a treatment dosage, for example, as shown in FIG. 3. As used herein, the ranges for the determined amount of CPSI may alternatively be ranges for the determined CPSI in conjunction with the at least one other parameter. For example, a low CPSI, e.g. below 0, may indicate that calcium phosphate scale is undersaturated and that corrosion is more likely to occur. Conversely, a high CPSI, e.g. above 0, may indicate that calcium phosphate scale is oversaturated and corrosion is less likely to occur. For example, a CPSI of less than 0.0; less than −0.10; less than −0.25; less than −0.50; less than −1.0; less than −2.0; or less than −3.0 may indicate that corrosion is likely to occur. A CPSI of greater than 0.0; greater than 0.10; greater than 0.25; greater than 0.50; greater than 1.0; greater than 2.0; or greater than 3.0 may indicate that corrosion is not likely to occur. Based on the determined CPSI and the at least one other parameter, an amount of a corrosion inhibitor treatment dosage may be determined and the amount may then be introduced into the water system 100, for example, to suppress corrosion of the water system 100.

In some embodiments, the determined CPSI and the at least one other parameter may be compared to a target percentage or predetermined target CPSI. The target CPSI may be, for example, associated with a minimal amount of corrosion inhibitor determined to adequately treat a water system. The target CPSI may be in the range of −5.0 to 5.0; −3.0 to 3.0; −2.0 to 2.0; −1.0 to 1.0; −0.75 to 0.75; −0.50 to 0.50; −0.25 to 0.25; or −0.10 to 0.10. Alternatively, the target CPSI may be 0.0. The determined corrosion inhibitor treatment dosage may be determined based on a difference between the determined CPSI and the at least one other parameter and the target CPSI. For example, a target CPSI may be 0.0. Thus, an amount of corrosion inhibitor may be applied to the water system 100 based on the difference between the determined CPSI and the at least one other parameter and 0.0, when the determined CPSI and the at least one other parameter is less than 0.0. Alternatively, if the determined CPSI and the at least one other parameter is greater than 0.0, no corrosion inhibitor may be applied to the water system 100.

A dosage control plan for the application of the corrosion inhibitor may be dependent upon the specific contents of the corrosion inhibitor treatment solution, a control plan, and system operating conditions. A dosage amount and rate curves can be developed for each treatment solution applied, to thereby allow for the change in dosage amounts and rates based on the calculated indices. These saturation-dosage curves may plot CPSI and/or at least one other parameter to a dose rate in ppm or ppb, as shown in, for example, the graph illustrated in FIG. 3.

FIG. 3 depicts saturation-dosage curves of a phosphorous-free/low phosphorous and zinc-free corrosion inhibitor treatment manufactured by ChemTreat, Inc., in ppm versus a ratio of: MAlk/(Cl+2SO₄) (“CASMR”), where MAlk is the total alkalinity level as CaCO₃, in a water system. Index curves, such as the curves illustrated in FIG. 3, are developed by determining a concentration of a specific corrosion inhibitor necessary to inhibit corrosion at various saturation index values along a spectrum. The dosage curve may be based on empirical or theoretical data and may vary for a specific water treatment system and for a specific corrosion inhibitor. The curves shown in FIG. 3 show a relationship between CASMR and the calcium phosphate saturation ratio (“CPSR”) and the corrosion inhibitor treatment dosage for carbon, 300, and 400 grade steel.

FIG. 3 includes a function of (1/CPSR)*CASMR. In FIG. 3, the CPSR was held constant. However, an increase in the CPSR would result in a decrease in a corrosion inhibitor dosage required. As shown in FIG. 3, as the CASMR increases, a corresponding corrosion inhibitor dosage required also increases. Although FIG. 3 depicts a corrosion inhibitor dosage versus CASMR and the CPSR, a similar curve may be developed and utilized with respect to corrosion inhibitor dosage versus CPSI and the at least one other parameter. For example, the dosage curve of FIG. 3 may be converted into a dosage curve of CPSI where the at least one other parameter includes CASMR.

In some embodiments, when the control system 10 determines a CPSI with at least one other parameter of the water system 100, the control system 10 may consult a graph, such as the graph of FIG. 3, or a table with comparable data. The table may, for example, express a relationship or relationships between the determined CPSI and the at least one other parameter and a corrosion inhibitor treatment dosage. The graph, table, or other information may be stored in a memory of the control system 10, to determine an amount of corrosion inhibitor to inject into the water system 100.

It will be understood that a dosage curve for a corrosion inhibitor for once-through applications may be different than cooling tower applications, as a cooling tower may have a long holding time for water in the system, e.g., hours or days, in comparison to a once-through application.

Control System

The control system 10 is configured to receive a measured or determined parameter(s) and can be configured to evaluate the measured or determined parameter(s) in conjunction with the CPSI, for example, including at least one other parameter. Then the control system 10 may then calculate a treatment dosage corresponding to the determined CPSI. The calculated treatment dosage can be output by the control system 10 for automatically controlling a supply pump to administer the calculated treatment dosage or outputting instructions to a user (e.g., via a user interface) to adjust the treatment dosage and regulate a corrosion inhibitor concentration in a water stream of a water system.

Parameters may be chosen from amongst parameters already being measured in a wastewater system. The parameters are not limited to those described and any combination of parameters may be utilized. Additional parameters may be included for greater accuracy and robustness of the model, leading to a more accurate prediction or determination of the amount of corrosion inhibitor treatment to apply to a system. Thus, the control system 10 may be retrofitted onto an existing water system and utilize pre-existing sensors to predict or determine the amount of corrosion inhibitor.

Once CPSI, for example, including at least one other parameter, is predicted or determined by the control system 10, the control system 10 may compare the predicted or determined CPSI to a target amount or range or threshold. If the predicted or determined CPSI exceeds the target amount or range, for example, exceeds the target range, the controller may determine an adequate or minimal amount of corrosion inhibitor that a supply pump should supply to the water stream to reduce the CPSI to within the target amount or range. If the predicted or determined CPSI, for example, including at least one other parameter, is within the target amount or range, the control system 10 may repeat the process until the predicted or determined CPSI exceeds the target amount or range.

The control system 10 can include hardware, such as a circuit for processing digital signals and a circuit for processing analog signals, for example. The control system 10 may include one or a plurality of circuit devices (e.g., an IC) or one or a plurality of circuit elements (e.g., a resistor, a capacitor) on a circuit board, for example. The control system 10 may be a central processing unit (CPU) or any other suitable processor, and can likewise include a plurality of processors, such as one or more processors. In some embodiments, for example, a single processor/controller can perform all of the steps of a process. In other embodiments, multiple processors/controllers can each perform individual steps of the process. The control system 10 may be or form part of a specialized or general purpose computer or processing system that may implement machine learning algorithms according to disclosed embodiments. One or more controllers, processors, or processing units, memory, and a bus that operatively couples various components, including the memory to the control system 10, may be used. The control system 10 may include a module that performs the methods described herein. The module may be programmed into the integrated circuits of the processor, or loaded from memory, storage device, or network or combinations thereof. For example, the control system 10 may execute operating and other system instructions, along with software algorithms, machine learning algorithms, computer-executable instructions, and processing functions. In some embodiments, the control system 10 may be a series or a plurality of controllers.

The controller may 10 be operational with numerous other general purpose or special purpose computing system environments or configurations. Examples of well-known computing systems, environments, and/or configurations that may be suitable for use with the disclosed embodiments may include, but are not limited to, personal computer systems, server computer systems, thin clients, thick clients, handheld devices, such as tablets and mobile devices, laptop devices, multiprocessor systems, microprocessor-based systems, set top boxes, programmable consumer electronics, network PCs, minicomputer systems, mainframe computer systems, and distributed cloud computing environments that include any of the above systems or devices, and the like.

Various components, such as probes or sensors of the water system, may be connected with each other via any type of digital data communication such as a communication network. Data may also be provided to the control system 10 through a network device, such as a wired or wireless Ethernet card, a wireless network adapter, or any other device designed to facilitate communication with other devices through a network. The network may be, for example, a Local Area Network (LAN), Wide Area Network (WAN), and computers and networks which form the Internet. The system may exchange data and communicate with other systems through the network. For example, the method may be practiced in clouding computing environments, including public, private, and hybrid clouds. The method can also or alternatively be practiced in distributed cloud computing environments where tasks are performed by remote processing devices that are linked through a communications network. In a distributed cloud computing environment, program modules may be located in both local and remote computer system storage media including memory storage devices. The system may be also be configured to work offline.

The present disclosure may further relate to a non-transitory computer-readable storage medium configured to store a computer-executable program that causes a computer to perform functions, such as those for implementing the disclosed methods and models. The computer-readable storage medium may further store the real time data collected by the control system 10 and computer-executable instructions.

The storage medium may include a memory and/or any other storage device. The memory may be, for example, random-access memory (RAM) of a computer. The memory may be a semiconductor memory such as an SRAM and a DRAM. The storage device may be, for example, a register, a magnetic storage device such as a hard disk device, an optical storage device such as an optical disk device, an internal or external hard drive, a server, a solid-state storage device, CD-ROM, DVD, other optical or magnetic disk storage, or other storage devices.

In some embodiments, a single controller and/or processor may perform multiple steps. For example, the single controller and/or processor may determine a calcium phosphate saturation index, determine at least one other parameter, determine a dosage of the corrosion inhibitor, and control administration of the corrosion inhibitor. In other embodiments, multiple processors and/or controllers may perform the process steps. For example, one or one controllers and/or processors may perform the calculations and determine the amount of corrosion inhibitor to provide to a water system, for example, based on a graph. Then, another one or more controllers and/or processors may and send the results to another controller for the injection of the corrosion inhibitor by the injection apparatus.

Corrosion Inhibitor Composition

The corrosion inhibitor composition is not particularly limited and may include metals such as tin, zinc, molybdenum, copper, and aluminum. The corrosion inhibitor composition may further comprise a reducing agent, a secondary corrosion inhibitor treatment, and/or a chelating agent. The corrosion inhibitor composition may further include other materials. For example, the composition may comprise, at least one of citric acid, benzotriazole and 2-Butenedioic acid (Z), bicarbonates for increasing the alkalinity of the solution, a polymeric dispersant, such as 2-acrylamido-2-methylpropane sulfonic acid (AMPS), for inhibiting silt or fouling, and polymaleic acid (PMA) for inhibiting scaling. The corrosion inhibitor composition may include, for example, non/low phosphorous corrosion inhibitors, or the like.

In some embodiments, the corrosion inhibitor composition includes a stannous salt selected from the group consisting of stannous sulfate, stannous bromide, stannous chloride, stannous oxide, stannous phosphate, stannous pyrophosphate, and stannous tetrafluroborate.

The corrosion composition may be a non-phosphate or low-phosphate corrosion inhibitor. For example a concentration of phosphate in the corrosion inhibitor may be: less than 100 ppm; less than 50 ppm; less than 10 ppm; less than 5 ppm; less than 1 ppm; less than 0.1 ppm; less than 0.01 ppm, or less than 0.001 ppm. Alternatively, there may be no phosphate in the corrosion inhibitor composition. In some embodiments, a process stream, such as a makeup stream 32, to which the corrosion inhibitor is applied to, may include less than 5 ppm of phosphate, less than 2 ppm of phosphate, less than 1 ppm, or less than 0.1 ppm of phosphate, less than 0.01 ppm of phosphate, or 0 ppm of phosphate, before application of the corrosion inhibitor.

A concentration of the corrosion inhibitor composition in the water stream may be in the range of 0.01 ppm to 400 ppm; 0.05 ppm to 300 ppm; 0.1 ppm to 250 ppm; 0.3 ppm to 200 ppm; 1 ppm to 100 ppm; 2 ppm to 50 ppm; or 3 ppm to 25 ppm. However, the concentration of the corrosion inhibitor composition may be higher, for example, to exceed a baseline demand of the system and thereby ensure treatment of vulnerable metal surfaces, resulting in excess corrosion inhibitor.

The corrosion inhibitor composition may be provided in an aqueous solution. The corrosion inhibitor in the aqueous solution may be present in an amount in the range of 0.01 to 50 wt %, 0.1 to 35 wt %, or 1 to 25 wt % or 10 to 20 wt %, in terms of total weight of the corrosion inhibitor treatment and the aqueous solution.

In some embodiments, the corrosion inhibitor composition may be provided in a shot/slug feed application, where a high concentration is fed over a short period of time. For example, in a shot/slug feed application, a concentration of the corrosion inhibitor composition in the water stream may be in the range of 50 to 500 ppm, 100 to 300 ppm, or 150 to 250 ppm. A concentration of the corrosion inhibitor composition in the water stream during a shot dose treatment may be in the range of 0.1 to 1000 ppm, 0.2 ppm to 50 ppm, or 0.5 to 10 ppm.

It will be appreciated that the above-disclosed features and functions, or alternatives thereof, may be desirably combined into different methods and systems. Also, various alternatives, modifications, variations or improvements may be subsequently made by those skilled in the art, and are also intended to be encompassed by the disclosed embodiments. As such, various changes may be made without departing from the spirit and scope of this disclosure.