WO2017021710A1

WO2017021710A1 - Corrosion control system and method

Info

Publication number: WO2017021710A1
Application number: PCT/GB2016/052345
Authority: WO
Inventors: Ian Sherrington
Original assignee: University Of Central Lancashire
Priority date: 2015-07-31
Filing date: 2016-07-29
Publication date: 2017-02-09
Also published as: GB201513513D0

Abstract

A corrosion control system for a mechanical apparatus, the system comprising measurement means for obtaining first data indicative of one or more parameters of an input process fluid of the mechanical apparatus and second data indicative of one or more conditions of the mechanical apparatus. The system further comprising supply means for supplying a corrosion- reducing substance to the mechanical apparatus, and control means. The control means is configured to receive first and second data from the measurement means and control the supply means to supply a predetermined amount of the corrosion-reducing additive to the mechanical apparatus in dependence on the first and second data.

Description

CORROSION CONTROL SYSTEM AND METHOD

[0001 ] This invention relates to a corrosion control system and method, and in particular relates to a corrosion control system and method for controlling the corrosion of a mechanical apparatus.

BACKGROUND

[0002] Mechanical apparatus may be prone to corrosion, especially if they are necessarily exposed to corrosion-causing substances during their normal operation. Engines, in particular, are vulnerable to corrosion, not least due to corrosion causing substances found in fuels.

Known corrosion causing substances found in engine fuels include sulphur and sulphur compounds which are particularly prevalent in low quality heavy fuel oils that are frequently used in large marine diesel engines. During combustion of such fuel, acidic residues are formed which lead to significant corrosion and deterioration of engine components. The cylinders of an engine are particularly prone to this form of corrosion.

[0003] It is known to provide counter measures to corrosion in engines by adding alkaline additives to the oils which are used to lubricate the piston-ring pack and piston during operation of the engine. The amount of alkaline additives to be added may be selected based on the type of fuel in use and various forms of assessment including a qualitative assessment of the amount of debris in oil samples taken from the engine. However, these assessments do not precisely assess the amount of additive required for a specific engine operating condition as this is a complex process and often results in too much or too little alkaline additive being added. Under provision of alkaline additive insufficiently inhibits corrosion and leads to unnecessary corrosion of the engine. On the other hand, over provision of alkaline additive can lead to the formation of hard deposits (e.g. calcium based deposits) which can cause sliding wear problems and changes in the tolerance between cylinder components.

[0004] The difficulty in accurately estimating the amount of required alkaline additive is exacerbated by recent changes in shipping practices. In particular, changes in the cost of fuel, partly as a consequence of recent restrictions on sulphur levels in fuel, have led to new operating procedures to reduce fuel costs. For example, marine vessels now frequently adopt the practice of "slow steaming" to improve fuel efficiency, where the vessels are operated at significantly less than their maximum speed. Engines operating significantly below their maximum load are also more susceptible to so-called "cold corrosion" wherein sulphuric acid forms on the liner walls of the engine cylinder and corrodes the liner surface.

[0005] WO-A-03/072912 (EXXONMOBIL RESEARCH AND ENGINEERING COMPANY) describes a device and method for the modification of an operating all-loss engine lubricant's properties in response to actual engine operating conditions. The described method includes modifying a base lubricant with performance enhancers. However, such a system may initially fluctuate between supplying an over provision of performance enhancers and supplying an under provision of performance enhancers. As such, there may be a long delay before an optimal amount of performance enhancer is being supplied. During this delay, the detrimental effects that the performance enhancers seek to mitigate will be ongoing.

[0006] Approaches have been described for the prevention of corrosion in water systems (JP2004085, JP2005337585, JP0914101 1 , WO03028910, WO2009137637, WO2009137636) and power plants (KR20040100596). In these systems, a measurement of the level of corrosive material in the supplied process fluid is made, sometimes in association with a measurement of the process fluid flow rate, in order to evaluate the quantity of neutralizing materials to be added to the process fluid to reduce corrosion. These systems are open loop arrangements, and no further feedback or measurement is employed to ensure that the determined quantity of additive correctly minimises corrosion or that it results in stable neutralisation of corrosive effects due to the composition of the process fluid or its combustion products.

[0007] It is an object of embodiments of the present invention to improve upon and/or overcome one or more problems associated with the prior art.

BRIEF SUMMARY OF THE DISCLOSURE

[0008] In accordance with an aspect of the present invention there is provided a corrosion control system for a mechanical apparatus, the system comprising:

measurement means for obtaining first data indicative of one or more parameters of an input process fluid of the mechanical apparatus and second data indicative of one or more conditions of the mechanical apparatus;

supply means for supplying a corrosion-reducing substance to the mechanical apparatus; and

control means;

wherein the control means is configured to receive first and second data from the measurement means and control the supply means to supply a predetermined amount of the corrosion-reducing additive to the mechanical apparatus in dependence on the first and second data.

[0009] The one or more conditions of the mechanical apparatus may include one or more of: a temperature of the mechanical apparatus, a pH level or level of acidity or alkalinity within the mechanical apparatus, a level of a corrosive agent or precursor to a corrosive agent in the mechanical apparatus, or a wear level of the mechanical apparatus

[0010] The one or more parameters of an input process fluid of the mechanical apparatus may include one or more of: a flow rate of input process fluid into the mechanical apparatus, a pH level or level of acidity or alkalinity of input process fluid into the mechanical apparatus, or a level, amount or concentration of a corrosive agent or precursor to a corrosive agent present in the process fluid. The measurement means may include means for a user to input data (e.g. a level, amount or concentration of a corrosive agent or precursor to a corrosive agent present in the process fluid)

[0011 ] The control means may be configured to control the supply means to supply a first predetermined amount of the corrosion-reducing substance in dependence on the first data, and subsequently control the supply means to supply a second predetermined amount of the corrosion-reducing additive to the mechanical apparatus in dependence on the second data.

[0012] When the mechanical apparatus is not operating, the first data may be obtained from a time period in which the mechanical apparatus was previously operating, or the first data is set to one or more predetermined values, where the one or more predetermined values may be zero.

[0013] In certain embodiments, the measurement means may comprise one or more transducers.

[0014] The supply means may comprise a first reservoir containing the corrosion-reducing substance. The supply means may further comprise one or more injectors for delivering the corrosion-reducing substance to the mechanical apparatus from the first reservoir. The corrosion control system may further comprise a second reservoir containing a lubricant, wherein the one or more injectors are configured to deliver the lubricant to the mechanical apparatus from the second reservoir. The lubricant may be mixed with the corrosion-reducing substance prior to delivery to the mechanical apparatus.

[0015] The corrosion-reducing substance may be selected to reduce corrosion caused to the mechanical apparatus by sulphur and/or sulphur compounds.

[0016] The corrosion-reducing substance may be selected to neutralise acidic residues.

[0017] The corrosion-reducing substance may be or contain an alkaline.

[0018] The corrosion-reducing substance may include one or more of calcium carbonate, an over based detergent, a volatile amine, hydrazine, or benzotriazole.

[0019] The corrosion-reducing substance may be supplied to the mechanical apparatus as a liquid and/or a gas.

[0020] In certain embodiments, the mechanical apparatus may be an engine, which may be a marine engine. The engine may be a diesel engine. [0021 ] In accordance with another aspect of the present invention, there is provided a computer-implemented method of reducing corrosion in a mechanical apparatus, comprising:

receiving first data indicative of one or more parameters of an input process fluid of the mechanical apparatus;

receiving second data indicative of one or more conditions of the mechanical apparatus;

controlling a control means to supply a predetermined amount of a corrosion- reducing additive to the mechanical apparatus in dependence on the first and second data.

[0022] The one or more conditions of the mechanical apparatus may include one or more of: a temperature of the mechanical apparatus, a pH level or level of acidity or alkalinity within the mechanical apparatus, a level of a corrosive agent or precursor to a corrosive agent in the mechanical apparatus, or a wear level of the mechanical apparatus

[0023] The one or more parameters of an input process fluid of the mechanical apparatus may include one or more of: a flow rate of input process fluid into the mechanical apparatus, or a pH level or level of acidity or alkalinity of input process fluid into the mechanical apparatus.

[0024] The method may comprise controlling the control means to supply a first

predetermined amount of a corrosion-reducing additive to the mechanical apparatus in dependence on the first data, and subsequently supply a second predetermined amount of a corrosion-reducing additive to the mechanical apparatus in dependence on the second data.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Embodiments of the invention are further described hereinafter with reference to the accompanying drawings, in which:

Figure 1 is a schematic diagram of a corrosion control system according to an embodiment of the present invention;

Figure 2 is a schematic diagram of a corrosion control system according to a specific embodiment of the present invention;

Figure 3 is a schematic diagram of a corrosion control system according to an alternative embodiment of the present invention; and

Figure 4 is a schematic diagram of a corrosion control system according to a further alternative embodiment of the present invention.

DETAILED DESCRIPTION

[0026] Figure 1 shows a schematic overview of a corrosion control system 10 in accordance with an embodiment of the present invention. The corrosion control system 10 includes measurement means 14 in the form of one or more measurement devices (e.g. transducers) communicably coupled to an mechanical apparatus 12 in which corrosion is to desirably be limited. The measurement means 14 is configured to obtain data that is indicative of one or more conditions of the mechanical apparatus 12 and one or more parameters of an input process fluid (e.g. fuel) to be supplied to or being supplied to the mechanical apparatus 12. The corrosion control system 10 further includes supply means 18 for supplying a corrosion- reducing substance to the mechanical apparatus 12, and a control means 16 that is

communicably coupled to each of the supply means 18 and measurement means 14. The control means 16 is configured to receive first data from the measurement means 14 indicative of one or more parameters of the input process fluid and second data indicative of one or more conditions of the mechanical apparatus 12, and control the supply means 18 to supply a predetermined amount of the corrosion-reducing substance to the mechanical apparatus 12 in dependence on the first and second data. The predetermined amount of the corrosion- reducing substance may be an absolute amount (e.g. a volume) or it may be a rate of delivery (e.g. volume per unit time), for example. The first and second data may be periodically updated such that predetermined amount may be periodically adjusted in dependence on the updated first and second data. By utilizing a data set relating to the input process fluid and a data set relating to the mechanical apparatus 12, an optimal amount of corrosion-reducing substance can be supplied quickly and effectively relative to prior art arrangements. In certain

embodiments, the control means may control the supply means 18 to supply a first

predetermined amount of the corrosion-reducing substance to the mechanical apparatus in dependence on the first data, and subsequently control the supply means 18 to supply a second predetermined amount of the corrosion-reducing additive to the mechanical apparatus 12 in dependence on the second data. In certain embodiments, the first predetermined amount and second predetermined amount may be discrete amounts. In other embodiments, the second predetermined amount may be supplied immediately after the first predetermined amount such that a continuous supply is provided. The corrosion control system 10 may provide an active, automated supply system where an initial amount of corrosion-reducing substance may be provided based on the first data and feedback from the mechanical apparatus 12 may be used to fine-tune the amount of corrosion-reducing substance subsequently added to the mechanical apparatus 12. Further supply of the corrosion-reducing substance may be controlled in dependence on the second data which may be periodically updated. In doing so, a suitable amount of corrosion-reducing additive may be added such that corrosion in the mechanical apparatus 12 is reduced without significantly increasing the formation of hard deposits due to oversupply of corrosion-reducing additive.

[0027] As noted above, the measurement means 14 may include any suitable means for obtaining data that is indicative of one or more conditions of the mechanical apparatus 12 and one or more parameters of the input process fluid. In obtaining such data, a determination may be made by the control means 16 concerning the present level or likelihood of future corrosion in the mechanical apparatus 12. On this basis, a determination concerning how much corrosion-reducing additive should be supplied to the mechanical apparatus 12 may be made, and the supply means 18 may be controlled by the control means 16 to supply the

predetermined amount of corrosion-reducing additive. The measurement means may include means (e.g. a user interface) to input data. That is, certain data may be obtained by the measurement means through user input.

[0028] In certain embodiments, the control means 16 may further control the supply means 18 so as to determine the locations on or in the mechanical apparatus 12 that the corrosion- reducing additive is supplied to. For example, the measurement means 14 may determine that corrosion is particularly prevalent or likely to be prevalent at one or more specific locations on or in the mechanical apparatus 12, and targeting the supply of corrosion-reducing additive to these one or more locations may further improve the effectiveness of the system 10.

[0029] The control means 16 may include a computer processor for receiving data from the measurement means 14 and/or controlling (i.e. providing instructions to) the supply means 18. The skilled person will appreciate that the term "computer processor" used herein

encompasses any suitable electronic or other processor including a process controller.

Similarly "computer implemented method" is considered to mean any electronically

implemented method that may be performed automatically.

[0030] The corrosion control system 10 of the present invention may be employed to control corrosion in any mechanical apparatus in which corrosion is likely to occur. The corrosion control system 10 of the present invention is particularly suitable to limiting corrosion in engines, and more particularly, in engines using fuels containing high levels of sulphur.

[0031 ] The corrosion-reducing substance may be any suitable substance that reduces or inhibits corrosion of a part of the mechanical apparatus 12. Particularly suitable corrosion- reducing substances act to neutralise acidic residues. The corrosion-reducing substance may be or include an alkaline. A commonly used corrosion-reducing substance in marine engine applications is calcium carbonate (CaC0₃), but a wide range of other non-limiting, illustrative examples of suitable corrosion-reducing substances include: over based detergents, volatile amines, hydrazine and benzotriazole. The corrosion-reducing substance to be used depends of the material to be protected. In certain embodiments, the corrosion-reducing substance may be a liquid and/or a gas that is provided to the mechanical apparatus 12. In certain embodiments, the corrosion-reducing substance may be provided in a carrier fluid such as a lubricant, fuel or detergent, and as such may be termed a corrosion-reducing additive. [0032] A specific embodiment of a corrosion control system 1 10 is shown schematically in Figure 2. The embodiment of Figure 2 illustrates several optional variations of the embodiment of Figure 1 which may be implemented independently or in any combination with one another. Like the embodiment of Figure 1 , the corrosion control system 1 10 of Figure 2 includes a measurement means 1 14, a control means 1 16 and a supply means 1 18 arranged to limit corrosion in a mechanical apparatus 1 12.

[0033] The measurement means 1 14 comprises a plurality of measurement devices that include a temperature sensor 120, a pH level sensor 122, a sulphur level sensor 124, a wear level sensor 126, a fuel flow rate sensor 128, and a fuel sulphur level sensor 130. That is, the measurement means 1 14 may obtain data that is indicative of one or more of the following example conditions of the mechanical apparatus 1 12: a temperature of the mechanical apparatus 1 12, a pH level within the mechanical apparatus 1 12, a sulphur level within the mechanical apparatus 1 12, or a wear level of the mechanical apparatus 1 12. Additionally, the measurement means 1 14 may obtain data that is indicative of one or more example parameters of the input fuel: a flow rate of fuel into the mechanical apparatus 1 12, or a sulphur level of fuel being provided to the mechanical apparatus 1 12. In alternative embodiments, any one or more of the plurality of measurement devices may be employed for obtaining data indicative of one or more conditions of the mechanical apparatus 1 12 and data indicative of one or more parameters of an input process fluid of the mechanical apparatus 1 12.

[0034] The temperature sensor 120 is arranged to determine a temperature of a part of the mechanical apparatus 1 12. For example, in embodiments where the mechanical apparatus 1 12 is an engine, the temperature sensor 120 may measure the temperature of a cylinder of the engine. The occurrence and rate of corrosion may depend on temperature so the monitoring of temperature may serve to facilitate a determination of a suitable amount of corrosion-reducing substance that is to be added to the mechanical apparatus 1 12. The temperature sensor 120 may include one or more sensors. Examples of suitable temperature sensors 120 include, but are not limited to, thermistors, thermocouples, thermometers, and semiconductor-based sensors. In alternative embodiments, any suitable temperature measuring means may be employed.

[0035] The pH level sensor 122 is arranged to determine a level of acidity or alkalinity in a part of the mechanical apparatus 1 12. For example, in embodiments where the mechanical apparatus 1 12 is an engine, the pH level sensor 122 may measure the level of acidity or alkalinity in or around a cylinder of the engine. In particular, the pH level sensor 122 may be arranged to measure the level of acidity or alkalinity in a fluid (e.g. a lubricant) within the mechanical apparatus 1 12. An elevated acidity level, for example, may be indicative of increased tendency to corrosion, so the monitoring of acidity and alkalinity levels may serve to facilitate a determination of a suitable amount of corrosion-reducing substance that is to be added to the mechanical apparatus 1 12. The pH level sensor 122 may include one or more sensors. In alternative embodiments, any suitable acidity and/or alkalinity level measuring means may be employed.

[0036] The sulphur level sensor 124 is arranged to determine a level of sulphur in a part of the mechanical apparatus 1 12. For example, in embodiments where the mechanical apparatus 1 12 is an engine, the sulphur level sensor 124 may measure the level of sulphur in or around a cylinder of the engine. The sulphur content of any compounds present in the mechanical apparatus 1 12 may be measured by the sulphur level sensor 124. Sulphur is a known corrosion-causing material so the corrosive effects of increasing sulphur levels in the mechanical apparatus can be actively countered by supplying corrosion-reducing substance to the mechanical apparatus 1 12. Such sulphur levels may increase over time due to an accumulation of sulphur and sulphur compounds from a fuel supply. By monitoring the actual sulphur level in the mechanical apparatus 1 12, a suitable amount of corrosion-reducing substance to be added to the mechanical apparatus 1 12 can be determined. The sulphur level sensor 124 may include one or more sensors. An example of a suitable sulphur level sensor 124 includes, but is not limited to, an electrochemical sensor. In alternative embodiments, any suitable sulphur level measuring means may be employed. In other embodiments where other substances may be a likely corrosive agent or a likely precursor to a corrosive agent, a sensor may be used to determine a level of that substance. Such a sensor may include, but is not necessarily limited to, an electrochemical sensor. In certain embodiments, a level of the substance may be determined by determining an acidity or alkalinity level. In such

embodiments, the pH sensor 122 described above may suffice.

[0037] The wear level sensor 126 is arranged to determine a level of wear in a part of the mechanical apparatus 1 12. For example, in embodiments where the mechanical apparatus 1 12 is an engine, the wear level sensor 126 may measure the level of wear in or around a cylinder and/or piston-ring of the engine. Suitable wear sensors 126 include, but are not limited to, any means or device for measuring an amount of debris in a part of the mechanical apparatus 1 12. In particular, the wear sensor 126 may determine a ratio of magnetic debris to non-magnetic debris, where the amount of non-magnetic debris may be indicative of corrosion (e.g. oxidized material such as rust). The amount of non-magnetic debris may be determined by measuring the total amount of debris and the amount of magnetic debris. Alternatively, the amount of non-magnetic debris may be determined by measuring the amount of magnetic debris and determining a ratio of non-magnetic debris to magnetic debris. Elevated levels of wear may be indicative of corrosion. The level of non-magnetic debris is particularly indicative of corrosion in contrast to more general wear due to sliding friction (which may generally be indicated by magnetic debris). The wear sensor 126 may include one or more sensors. In alternative embodiments, any suitable wear level measuring means may be employed.

[0038] The fuel flow rate sensor 128 is arranged to determine a flow rate of fuel being supplied to the mechanical apparatus 1 12. The fuel flow rate sensor may be arranged in the mechanical apparatus 1 12 or it may be arranged externally of the mechanical apparatus 1 12 (e.g. in or along a fuel inlet line). If the sulphur content of a particular fuel supply is known, or can be estimated or otherwise deduced, the fuel flow rate may be a useful indicator of the amount of corrosion-causing material being introduced into the mechanical apparatus 1 12. The fuel flow rate sensor 128 may be one or more sensors. Suitable fuel flow rate sensors 128 include, but are not limited to, any suitable means or device for determining a flow rate of a flowing fluid. Non-limiting, illustrative examples include positive-displacement flow meters, pressure-based flow meters, optical flow meters, open-channel flow meters, thermal mass flow meters, electromagnetic flow meters, ultrasonic flow meters, coriolis flow meters, and Doppler flow meters. In alternative embodiments, any suitable flow rate measuring means may be employed. In certain embodiments where the input process fluid is not fuel, a similar input process fluid flow rate sensor (in place of the fuel flow rate sensor 128) may be utilized.

[0039] The fuel sulphur level sensor 130 is arranged to determine a level of sulphur in the fuel being supplied to the mechanical apparatus 1 12. The sulphur content of the fuel being supplied to the mechanical apparatus 1 12 may be measured by the fuel sulphur level sensor 130. The fuel sulphur level sensor 130 may be arranged in the mechanical apparatus 1 12 or it may be arranged externally of the mechanical apparatus 1 12 (e.g. in or along a fuel inlet line). As noted above, sulphur is a known corrosion-causing material so the corrosive effects of increasing sulphur levels in the mechanical apparatus can be actively countered by supplying corrosion-reducing additive to the mechanical apparatus 1 12. The level of sulphur in the fuel being supplied to the mechanical apparatus 1 12 allows a determination to be made concerning the amount of corrosion-causing materials being introduced in the mechanical apparatus 1 12. This determination may be made more accurate by combining data from the fuel sulphur level sensor 130 with the fuel flow rate sensor 128. The fuel sulphur level sensor 130 may include one or more sensors. An example of a suitable fuel sulphur level sensor 130 includes, but is not limited to, an electrochemical sensor. In certain embodiments, the fuel sulphur level sensor 130 may be a user interface that is configured to permit the input of a fuel sulphur level. For example, the fuel sulphur level may be known or may be determined from the type of fuel being used or known data associated with the fuel. In alternative embodiments, any suitable fuel sulphur level measuring means may be employed. In other embodiments, e.g. where the input process fluid is not fuel and/or the corrosive agent or precursor is not sulphur, other similar corrosive agent sensors may be used to determine a level, amount or concentration of corrosive agent or precursor to a corrosive agent in the input process fluid.

[0040] In other embodiments, other measurement means may be employed. For example, a humidity sensor may form part of the measurement means. In certain embodiments in which the mechanical apparatus is an engine, sensors or other means may be provided for obtaining data relating to the engine speed, load and/or pressure, to provide data indicative of one or more conditions of the mechanical apparatus.

[0041] In an example, the control means 1 16 controls the supply means 1 18 to supply a first predetermined amount of corrosion-reducing substance to the mechanical apparatus 1 12 in dependence on first data received from at least one of the sensors 128, 130. Subsequently, the control means 1 16 controls the supply means 1 18 to supply a second predetermined amount of corrosion-reducing substance to the mechanical apparatus 1 12 in dependence on second data received from at least one of the sensors 120, 122, 124, 126. In preferable embodiments, data from multiple sensors is utilized by the control means 1 16 to determine the predetermined amount of corrosion-reducing additive. In certain embodiments, an optimum determination of the predetermined amount of corrosion-reducing additive may be achieved by using data from an increased number of sensors.

[0042] In the embodiment shown in Figure 2, the supply means 1 18 includes an additive reservoir 140 for storing a supply of the corrosion-reducing substance, and an additive injector 138 for supplying the corrosion-reducing substance to the mechanical apparatus 1 12 from the additive reservoir 140. The supply of corrosion-reducing substance contained in the additive reservoir 140 may or may not be in a carrier fluid. In certain embodiments, the control means 1 16 may control the supply means 1 18 to supply corrosion-reducing substance to one or more predetermined locations within the mechanical apparatus 1 12. For example, the additive injector 138 may include a plurality of nozzles and the control means 1 16 may control the additive injector 138 to supply corrosion-reducing substance through predetermined nozzles so as to target the supply of the corrosion-reducing substance to selected parts of the mechanical apparatus 1 12. Such targeted supply may be in response to an increased need for corrosion- reducing substance in one or more particular parts of the mechanical apparatus 1 12 as determined by the control means 1 16 based on first and second data received from the measurement means 1 14. In such embodiments, the various sensors of the measurement means 1 14 may be distributed about the mechanical apparatus 1 12 so as to actively monitor the need for corrosion-reducing substance at selected locations.

[0043] The corrosion control system 1 10 of Figure 2 additionally includes calibration means 132 in the form of a calibration device that is configured to provide verification that the corrosion control system 1 10 is operating in a desired manner. For example, the corrosion control system 1 10 may monitor one or more conditions of the corrosion-reducing additive to ensure that its properties are within expected ranges. As an example, the calibration means 132 may determine a pH level of the corrosion-reducing substance so that the predetermined amount of corrosion-reducing substance can be more accurately determined by the control means 1 16. In certain embodiments, the calibration means 132 may be communicably coupled to any of the mechanical apparatus 1 12, the measurement means 1 14, the control means 1 16, and the supply means 1 18.

[0044] The corrosion control system 1 10 of Figure 2 additionally includes data recording means 134 in the form of a data recorder for recording information received from the measurement means 1 14 and/or information provided by the control means 1 16 to the supply means 1 18. The recording of information may assist the operator in optimizing how the control means 1 16 determines the predetermined amount of corrosion-reducing additive based on information provided by the measurement means 1 14. In certain embodiments, the data recording means 134 may be a computer or other electronic memory. In certain embodiments the data recording means 134 may store a record of the operation of the corrosion control system 1 10 (e.g. over the entire lifetime of the system). Such information may be valuable for use in system optimization and/or in predicting maintenance requirements such as the likely refilling interval of the additive reservoir 140.

[0045] The corrosion control system 1 10 of Figure 2 additionally includes a user interface 136 that enables a user to interface with the control means 1 16.

[0046] Figure 3 shows a corrosion control system 210 according to an alternative embodiment of the present invention. The corrosion control system 210 of Figure 3 is identical to the corrosion control system 1 10 of Figure 2 but additionally includes a lubricant reservoir 242 (equivalent components are indicated by reference numerals that are transposed by 100). Additionally, the additive injector 138 of the embodiment of Figure 2 has been replaced by an additive and lubricant injector 238 that is fluidly connected to each of the additive reservoir 240 and the lubricant reservoir 242. Lubricant may be supplied to the mechanical apparatus 212 from the lubricant reservoir 242 to the mechanical apparatus 212 via the additive and lubricant injector 238 in order to provide lubricant to any wearable parts of the mechanical apparatus 212. The additive and lubricant injector 238 may concurrently supply lubricant and corrosion- reducing substance to the mechanical apparatus 212 (e.g. through a same or different nozzle). Alternatively, the additive and lubricant injector 238 may alternate the supply of lubricant and corrosion-reducing substance to the mechanical apparatus 212. In certain embodiments, the lubricant may be supplied to the mechanical apparatus 212 in accordance with the method set out in GB-A-2357556 (University of Central Lancashire) which is hereby incorporated in its entirety by reference.

[0047] Figure 4 shows a corrosion control system 310 according to an alternative embodiment of the present invention. The corrosion control system 310 of Figure 4 is identical to the corrosion control system 210 of Figure 3 but additionally includes a mixer 344 (equivalent components are indicated by reference numerals that are transposed by 100). The mixer 344 is configured to mix lubricant from the lubricant reservoir 342 with corrosion-reducing substance from the additive reservoir 340 prior to the mixed lubricant and corrosion-reducing substance being supplied to the mechanical apparatus 312 via the additive and lubricant injector 338. In this embodiment, the amount of corrosion-reducing substance supplied to the mechanical apparatus 312 may be varied by the control means 316 by varying the amount of corrosion- reducing substance supplied to the mixer 344 from the additive reservoir 340 and/or by varying the amount of mixed additive and lubricant supplied to the mechanical apparatus 312 from the mixer 344.

[0048] For an engine, the corrosion control system according to certain embodiments of the present invention may be operated when the engine is operating or during periods when the engine is not operating (i.e. shutdown). It may be advantageous to operate the corrosion control system during shutdown of an engine since any previously supplied corrosion-reducing substance may become depleted or exhausted due to condensation effects (as the engine cools). Additionally, residual corrosion-causing materials are often present in volume of gas that remains in the engine after shut down. Furthermore, temperature changes in the engine (as it cools following shutdown and heats up following start up) may give rise to changes in the chemical state of residual materials and might increase the amount of corrosion-causing substances that are present. As such, the need for corrosion-reducing additive is not necessarily precluded by engine shutdown. When operating the corrosion control system when the engine (or other mechanical apparatus) is not operational, the first data relating to one or more parameters of the input process fluid may be obtained from a time period preceding the shutdown of the engine. Alternatively, the first data may be set to one or more predetermined values, e.g. based on the residual effect of previously present input process fluid. In certain embodiments, the predetermined value may be zero. In certain embodiments, the corrosion control system may be used with other mechanical apparatus (other than engines) during shutdown of the mechanical apparatus (e.g. during periods when input process fluid is not being provided to the mechanical apparatus).

[0049] To further minimize the effects of corrosion during shutdown, a gas may be introduced into an engine (e.g. to the cylinders) to neutralize any sulphur compounds in any residual gas present in the engine. Additionally or alternatively, any residual gases in the engine may be purged (e.g. by a pump) to minimize the risk of corrosion. The purged residual gases may be replaced with air or one or more other gases (e.g. nitrogen) that is/are known not to cause corrosion. [0050] In certain embodiments, the corrosion control system may additionally include means to supply one or more acid-based additives to one or more parts of the mechanical apparatus. Such means may be controlled by the control means in dependence on data received from the measurement means, for example, to counteract the undesired effects of any potential oversupply of the corrosion-reducing additive to the mechanical apparatus.

[0051 ] The corrosion control system according to embodiments of the present invention may be used to reduce corrosion in any mechanical apparatus in which corrosion may arise. As noted above, one application of the corrosion control system is in respect of engines, and particularly diesel engines such as those used in marine vessels. Other applications include, but are not limited to, fuel lines, peripheral engine components, and gas pipelines. In the case of a gas pipeline, for example, the measurement means of the corrosion control system may obtain first data indicative of the gas flow rate provided to the pipeline, and the control means may control the supply means to provide a first predetermined amount of corrosion-reducing substance to the pipeline in dependence on the gas flow rate data. Subsequent, second predetermined amounts of corrosion-reducing substance may be provided to the pipeline under the control of the control means in dependence on data indicative of one or more conditions of the pipeline. For example, the one or more conditions may include a temperature or a humidity level in the pipeline. If there is a high flow rate of gas, more corrosion-reducing substance may be supplied to counter the corrosive effects of any corrosion-causing materials within the gas. Conversely, if the flow rate of gas is low, less corrosion-reducing substance will be required. As demonstrated by the above-described embodiments, the measurement means may obtain data that is indicative of other, additional or alternative, conditions of the pipeline or parameters of the input process fluid (e.g. gas).

[0052] Embodiments of the present invention may therefore serve to provide an optimal amount of corrosion-reducing substance to a mechanical apparatus such that corrosion may be reduced whilst avoiding or reducing any problems arising from oversupply of corrosion-reducing additive. By providing an initial first predetermined amount of corrosion-reducing substance and then subsequently providing a second predetermined amount of corrosion-reducing substance, embodiments of the present invention provide an iterative system and method that optimizes the use of corrosion-reducing substance. For example, the first data provides a first order indication of the required amount of corrosion-reducing substance, whilst the second data may be utilized to fine tune the supply of corrosion-reducing substance. Embodiments of the present invention may therefore provide a system and method of supplying an optimal amount of corrosion-reducing substance that quickly stabilises around an ideal amount of corrosion- reducing substance relative to prior art arrangements. Therefore, corrosion that may occur due to a suboptimal supply of corrosion-reducing substance may be reduced relative to prior art arrangements.

[0053] Throughout the description and claims of this specification, the words "comprise" and "contain" and variations of them mean "including but not limited to", and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

[0054] Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

[0055] The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

Claims

A corrosion control system for a mechanical apparatus, the system comprising: measurement means for obtaining first data indicative of one or more parameters of an input process fluid of the mechanical apparatus and second data indicative of one or more conditions of the mechanical apparatus;

control means;

The corrosion control system of claim 1 , wherein the one or more conditions of the mechanical apparatus include one or more of: a temperature of the mechanical apparatus, a pH level or level of acidity or alkalinity within the mechanical apparatus, a level of a corrosive agent or precursor to a corrosive agent in the mechanical apparatus, or a wear level of the mechanical apparatus

The corrosion control system of claim 1 or 2, wherein the one or more parameters of an input process fluid of the mechanical apparatus include one or more of: a flow rate of input process fluid into the mechanical apparatus, a pH level or level of acidity or alkalinity of input process fluid into the mechanical apparatus, or a level, amount or concentration of a corrosive agent or precursor to a corrosive agent present in the process fluid. .

The corrosion control system of any preceding claim, wherein the control means is configured to control the supply means to supply a first predetermined amount of the corrosion-reducing substance in dependence on the first data, and subsequently control the supply means to supply a second predetermined amount of the corrosion-reducing additive to the mechanical apparatus in dependence on the second data.

5. The corrosion control system of any preceding claim, wherein when the

mechanical apparatus is not operating, the first data is obtained from a time period in which the mechanical apparatus was previously operating, or the first data is set to one or more predetermined values.

6. The corrosion control system of claim 5, wherein the one or more predetermined values is zero.

7. The corrosion control system of any preceding claim, wherein the measurement means comprises one or more transducers.

8. The corrosion control system of any preceding claim, wherein the supply means comprises a first reservoir containing the corrosion-reducing substance.

9. The corrosion control system of claim 8, wherein the supply means further

comprises one or more injectors for delivering the corrosion-reducing substance to the mechanical apparatus from the first reservoir.

10. The corrosion control system of claim 9, further comprising a second reservoir containing a lubricant, wherein the one or more injectors are configured to deliver the lubricant to the mechanical apparatus from the second reservoir.

1 1. The corrosion control system of claim 10, wherein the lubricant is mixed with the corrosion-reducing substance prior to delivery to the mechanical apparatus.

12. The corrosion control system of any preceding claim, wherein the corrosion- reducing substance is selected to reduce corrosion caused to the mechanical apparatus by sulphur and/or sulphur compounds.

13. The corrosion control system of any preceding claim, wherein the corrosion- reducing substance is selected to neutralise acidic residues.

14. The corrosion control system of any preceding claim, wherein the corrosion- reducing substance is or contains an alkaline.

The corrosion control system of any preceding claim, wherein the corrosion- reducing substance includes one or more of calcium carbonate, an over based detergent, volatile amine, hydrazine, or benzotriazole.

16. The corrosion control system of any preceding claim, wherein the corrosion- reducing substance is supplied to the mechanical apparatus as a liquid and/or a gas.

17. The corrosion control system of any preceding claim, wherein the mechanical apparatus is an engine.

18. The corrosion control system of claim 17, wherein the engine is a marine engine.

19. The corrosion control system of claim 17 or 18, wherein the engine is a diesel engine.

20. A computer-implemented method of reducing corrosion in a mechanical

apparatus, comprising:

21 . The method of claim 20, wherein the one or more conditions of the mechanical apparatus include one or more of: a temperature of the mechanical apparatus, a pH level or level of acidity or alkalinity within the mechanical apparatus, a level of a corrosive agent or precursor to a corrosive agent in the mechanical apparatus, or a wear level of the mechanical apparatus

22. The method of claim 20 or 21 , wherein the one or more parameters of an input process fluid of the mechanical apparatus include one or more of: a flow rate of input process fluid into the mechanical apparatus, or a pH level or level of acidity or alkalinity of input process fluid into the mechanical apparatus.

23. The method of any of claims 20 to 22, comprising controlling the control means to supply a first predetermined amount of a corrosion-reducing additive to the mechanical apparatus in dependence on the first data, and subsequently supply a second

predetermined amount of a corrosion-reducing additive to the mechanical apparatus in dependence on the second data.

24. A corrosion control system substantially as hereinbefore described with reference to the accompanying drawings.

25. A computer-implemented method of reducing corrosion in a mechanical apparatus substantially as hereinbefore described with reference to the accompanying drawings.