Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N17/00—Investigating resistance of materials to the weather, to corrosion, or to light
  • G01N17/04—Corrosion probes
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
  • D21H21/02—Agents for preventing deposition on the paper mill equipment, e.g. pitch or slime control
  • D21H21/04—Slime-control agents
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
  • D21H21/14—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by function or properties in or on the paper
  • D21H21/36—Biocidal agents, e.g. fungicidal, bactericidal, insecticidal agents
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H23/00—Processes or apparatus for adding material to the pulp or to the paper
  • D21H23/02—Processes or apparatus for adding material to the pulp or to the paper characterised by the manner in which substances are added
  • D21H23/04—Addition to the pulp; After-treatment of added substances in the pulp
  • D21H23/20—Apparatus therefor
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
  • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
  • G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
  • G01N27/041—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body

Definitions

• the present invention relates to an improved method for minimizing corrosion damages of machinery for paper or board manufacturing.
• Microorganisms are present in paper and board machines every day. Their entry into the process is inevitable, because the circulating water contains biodegradable dissolved substances, temperature and pH are typically favourable for microbial life, and the machines are open processes subject to contaminants from air, water, and non-sterile raw materials. Paper and board machines can support growth of very different kinds of microorganism; but most common organisms are bacteria and fungi.
• a thorough review of paper machine microbiology, about the microorganisms and their impact on paper making, is presented in Chapter 6: Paper machine microbiology, pp. 181-198, by Marko Kolari, in Handbook of Papermaking chemistry 2007, Raimo Alen (Ed.), Finnish Paper Engineers' Association, Helsinki, Finland.
• Microorganisms can cause a number of problems in papermaking, if countermeasures are not taken. Microbes may affect both the functioning of the chemistry of papermaking and the quality of the end product. Starch is one of the most easily digestible nutrients for microbes, but also some other additive slurries are prone to spoilage. High microbial activity, for example in a coated broke tower, can lower the pH and thus have a marked effect on wet- end chemistry. High microbial activity can also create strong odours that may be a nuisance or even a danger to personnel, and also destructive for product quality in packaging grades.
• Biocide dosing to the process waters is the most common way to combat microbes.
• a typical biocide program is composed of individual treatments of the different parts of the process system, such as incoming raw water, additive storages, paper machine water circuits, and the broke system. If biocide treatment in one part fails, it typically affects the whole machine.
• biocide The type of biocide to be selected depends on the point of application, the performance target and chemical compatibility to the system.
• oxidizing biocides are nowadays widely used due to their cost -efficiency.
• Common oxidizing biocides are for example the "free halogen” sources such as sodium hypochlorite, hypobromous acid and chlorine dioxide.
• stabilized halogens such as halogenated hydantoins, e.g., bromochloro-dimethylhydantoin or partially halogenated hydantoins such as monochloro- dimethylhydantoin.
• haloamines such as chloramines and bromamines
• an ammonium source such as ammonium sulfate, ammonium chloride, ammonium bromide, ammonium phosphate, ammonium nitrate or any other ammonium salt, including urea
• an oxidant such as sodium hypochlorite
• Corrosion is a particular concern in the "short loop," or short circulation section, of a paper machine, and in the su bsequent press and drying section.
• pulp stock is passed into a headbox, which distributes the pulp stock onto a moving wire in a forming section.
• the paper sheet is formed in the forming section and then sent to presses and dryers for finishing.
• the short loop is a system that re-circulates and recycles excess water from the pulp stock. The excess water is collected in a wire pit in the forming section and then a major portion thereof is recirculated back to the headbox for re-use.
• em bodiments of the present disclosure in one aspect, relate to methods to monitor and/or control the qua ntity of vapor phase corrosion, devices, and the like.
• the present invention provides, a method for monitoring the vapor phase corrosion in a paper or board machine comprising obtaining information regarding the rate of vapor phase corrosion over a time period; and using the information to determine how to adjust the dosing of an oxidizing biocide in a paper or board making process.
• a modified ER device comprising an ER probe and a cooling unit is provided.
• a method comprising obtaining, by a computing device, information regarding the rate of vapor phase corrosion over a time period; and using the information to determine, by a computing device, how to adjust the dosing of an oxidizing biocide in a paper or board making process, is provided.
• a system comprising at least one computing device; and a method application executable in the at least one computing device, the method application comprising: logic that obtains information regarding the rate of vapor phase corrosion over a time period; and logic that uses the information to determine how to adjust the dosing of an oxidizing biocide in a paper or board making process, is provided.
• Figure 1 illustrates a cross-sectional view of an embodiment of the present disclosure.
• Figure 2A illustrates a perspective view of the modified ER probe (i.e., an embodiment of a cooling unit is disposed around the ER probe).
• Figure 2B illustrates a schematic perspective view of an ER probe.
• Figure 3 illustrate a graph showing example data about measured rate of corrosion (metal loss of the sensing element, ⁇ ) during a period from 18 th of December to 3 rd of January.
• Figure 4 illustrates a graph that shows example data about measured rate of corrosion (metal loss of the sensing element, ⁇ ) during a five-week period.
• Figure 5 is a schematic of a measurement system including a computer device.
• Figure 6 is a flow chart of an example of monitoring the vapor phase corrosion.
• Embodiments of the present disclosure will employ, unless otherwise indicated, techniques of paper science, chemistry, and the like, which are within the skill of the art. Such techniques are explained ful ly in the literature.
• the present invention provides a method for monitoring the vapor phase corrosion in a paper or board machine. It comprises the steps of obtaining information regarding the rate of vapor phase corrosion over a time period; and using the information to determine how to adjust the dosing of an oxidizing biocide in a paper or board making process.
• the information is obtained using a modified electrical resistance (ER) probe equipped with an ER probe and a cooling unit disposed around the ER probe.
• the information includes preferably measurement information of the corrosion or determination of the corrosion rate by measurements.
• the information is obtained using a temperature measurement sensor to measure the temperature of one or more of the following: the ER probe, the air around the ER probe, or the air outside of the ER probe.
• the amount of the oxidizing biocide is adjusted based on the information obtained regarding vapor phase corrosion.
• the amount of the oxidizing biocide is adjusted based on the information obtained regarding vapor phase corrosion.
• Obtaining information preferably includes measuring an electrical resistance of an element in the modified ER probe.
• an increase in the electrical resistance of the element over a time period indicates that the element undergoes reduction, and a rate of corrosion is determined from the reduction of the element over the time period.
• the method preferably further comprises controlling the temperature difference between the air outside of the modified ER probe and the surface of the ER probe.
• the method may be modified by assisting the data collection and the use of information by a computing device.
• a method comprising obtaining, by a computing device information regarding the rate of vapor phase corrosion over a time period; and using the information to determine, by a computing device, how to adjust the dosing of an oxidizing biocide in a paper or board making process.
• the method preferably further comprises adjusting, by the computing device, the amount of the oxidizing biocide based on the information obtained regarding vapor phase corrosion.
• the information obtained preferably includes measuring, by the computing device, an electrical resistance of an element in a modified ER probe.
• the method preferably further comprises controlling, by a computing device, the temperature difference between the air outside of a modified ER probe and a surface of an ER probe.
• the present invention provides a modified electrical resistance (ER) device. It comprises an ER probe and a cooling unit. This device is suitable for use in the above described methods for monitoring the vapor phase corrosion in a paper or board machine described in the first aspect.
• the cooling device of the modified ER probe preferably includes a structure disposed around the ER probe, wherein a cavity is formed between the structure and the ER probe, and wherein the structure includes one or more openings.
• the cooling device is configured to flow a cooling medium in the cavity.
• the cooling device is directly attached to the ER probe to control the temperature of the ER probe.
• the cooling device is not directly attached to the E probe, and the cooling medium is used to control the temperature of the ER probe.
• the modified ER probe further comprises a temperature measurement sensor to measure the temperature of one or more of the following: the ER probe, the air around the ER probe, or the air outside of the ER probe.
• a yet further aspect of the present invention is a system able to perform the required processes described above.
• This system comprises at least one computing device; and a method application executable in the at least one computing device, the measuring application comprising: logic that obtains information regarding the rate of vapor phase corrosion over a time period; and logic that uses the information to determine how to adjust the dosing of an oxidizing biocide in a paper or board making process.
• the system preferably further comprises logic that adjusts the amount of the oxidizing biocide based on the information obtained regarding vapor phase corrosion.
• Obtaining information preferably includes logic that measures an electrical resistance of an element in a modified ER probe.
• the system preferably further comprises logic that controls the temperature difference between the air outside of a modified ER probe and a surface of an ER probe.
• method application is meant the means for carrying out a method for monitoring the vapor phase corrosion in a paper or board machine, comprising obtaining information regarding the rate of vapor phase corrosion over a time period; and using the information to determine how to adjust the dosing of an oxidizing biocide in a paper or board making process, as described above or means for measuring or determining the required elements in a measuring application.
• the method application is typically implemented by portions of computer software executable in a computing device.
• logic portions of computer software which are executed in a computing device causing the computing device to perform logical operations as defined in the method for monitoring the vapor phase corrosion in a paper or board machine, comprising obtaining information regarding the rate of vapor phase corrosion over a time period; and using the information to determine how to adjust the dosing of an oxidizing biocide in a paper or board making process, as described above or means for measuring or determining the required elements in a measuring application.
• the various aspects of the present invention are further described by the following embodiments. Embodiments of the present disclosure include methods to monitor and/or control the quantity of vapor phase corrosion, devices, and the like.
• em bodiments of the present disclosure can include monitoring the rate and/or quantity of vapor phase corrosion of paper machinery (e.g., uniform corrosion) on-line.
• the rate and/or quantity of vapor phase corrosion can be used to control the dosing amounts of oxidizing biocides as an effective way to minimize vapor phase corrosion in a paper machine in a timely manner.
• One or more embodiments of the present disclosure relate to an improved method for minimizing corrosion damages of machinery for paper or board manufacturing, and in particular, minimizing corrosion damages caused by dosing of biocides to said aqueous manufacturing process. This can be accomplished by use of modified E probe as an on-l ine vapor-phase corrosion sensor for monitoring corrosion rate and by use of that information for adjusting biocide dosing in time.
• An exemplary embodiment of the present disclosure can be advantageous over the current methods where information on corrosion rate is based on weight loss information from corrosion coupons that have been held in the process for several weeks. Other methods provide information with a significant time delay only and there is not an opportunity to react quickly in changes in corrosiveness.
• An exemplary em bodiment of the present disclosure enables the use of on-l ine and real-time or semi-real-time information on the corrosion rate that can be directly used for adjusting oxidizing biocide dosing quantity and thus, e.g., sudden peaks with high corrosion rate can be stopped in a timely fashion (e.g., hours or days).
• the oxidizing biocide can be added to one or more points in the process and these can include the pulp line, water line, or tanks.
• An exemplary embodiment of the present disclosure includes monitoring the rate of vapor phase corrosion of paper machinery on-line and using that information to control the dosing amounts of oxidizing biocides. Monitoring the corrosion in this manner can be an effective way to minimize vapor phase corrosion in a paper machine.
• an exemplary em bodiment of the present disclosure includes an on-line sensor based on a modified Electrical Resistance (ER) probe, such as electrical resistance technique, that can be used as an on-l ine sensor, which can be used to determine if the amount of biocide should be adjusted (e.g., manually or automatically adjusting biocide dosing pumps).
• ER Electrical Resistance
• the modified ER probe can be part of a modified ER probe system.
• the ER probe can be equipped with an ER probe and a cooling unit and optional ly a temperature measurement device.
• the cooling unit enables the formation of condensate water on the probe surface.
• the modified ER probe such as a cooling unit and temperature measurement device, can be in communication with a computer system, such as including an on-l ine data collection system, a data interpretation system, a control system for the cooling unit, and the like.
• a computer system such as including an on-l ine data collection system, a data interpretation system, a control system for the cooling unit, and the like.
• the modified ER probe may include one of the ER probes sold by CAPROCO or ROXAR.
• the modified ER probe can use the electrical resistance technique as an "on-l ine" method for monitoring the rate of corrosion and metal loss for equipment including one or more metall ic structures or components of the ER probe, where the ER probe includes an appropriate measurement system to measure the electrical resistance of the element.
• Reduction (metal loss) in the cross section of the element of the ER probe due to corrosion increases the elements electrical resistance. Measurements showing an increase in the electrical resistance indicates that the element is corroding, which can be due to the oxidizing biocide interaction with the element.
• Monitoring the electrical resistance over a time period correlates to the rate of corrosion. Once the rate of corrosion is known, the amount of biocide being used can be adjusted.
• FIGU RE 1 illustrates a cross-sectional view of an exemplary embodiment of the present disclosure.
• the modified ER probe includes a ER probe and a cooling unit that includes a structure, preferably a mantel with an annular cavity disposed or arranged around the ER probe, so that the temperature of the surface can be controlled and, optional ly, a temperature sensor (not shown) to monitor the temperature.
• the ER probe includes one or more elements, where the resistance across the electrode can be determined and/or measured by the modified ER probe or computer system interfaced with the modified ER probe.
• the structure can be contoured to flow the cooling medium.
• the structure can have a cross section that is similar to the ER probe cross section.
• the structure can have a circular cross section, polygonal cross section or the like.
• the structure can include one or more openings so that a cooling medium, e.g., a gas or a fl uid, can flow in and out of the cavity of the structure.
• the cooling unit includes an opening for the ER probe so that the sensor (e.g., element) of the probe (See the rectangular shaped structure in FIGU RE 2) is exposed to the environment around the ER probe.
• the openings can be the same or a different size (e.g., circular, polygonal, and the l ike) and on the order of millimeters to centimeters.
• the structure can have 1 to 100 openings.
• a flow system can be used to flow the cooling medium and can include flow regulators, piezoelectric systems, and the like.
• a surface of the cool ing unit which has been cooled down to a specified temperature, is arranged to be in connection, preferably directly attached (touch), with a surface of the probe thereby cool ing the probe head and the sensing element.
• the cooling unit is not in direct contact with the ER probe, so a cool gas, preferably air, can be circulated in the area around the ER probe to control the temperature of the ER probe.
• the modified ER probe can also include a temperature sensor so that the temperature can be monitored as a function of the results produced by the ER probe.
• the temperature sensor can include one or more temperature detection sensors disposed on or outside of the modified ER probe.
• the temperature measurement sensor(s) can be disposed adjacent the ER probe to measure the temperature of one or more of the fol lowing: the ER probe, the air around the ER probe, or the air outside of the ER probe.
• FIGU RE 2A illustrates a perspective view of an embodiment of the modified ER probe (i.e., an em bodiment of a cooling unit is disposed around the ER probe).
• FIGU RE 2A illustrates an em bodiment of a configuration to change the temperature (e.g., reduce the temperature) using the cooling unit by flowing a cooling medium through the structure.
• FIGU RE 2B illustrates a schematic perspective view of an ER probe.
• Embodiments of the present disclosure may overcome these problems by cooling the measurement head of the E probe.
• cooling the ER probe can create conditions where a sensing element in the ER probe is sensitive to reacting to changes in the amount of corrosive chemicals in the air and thus gives information on the rate of vapor phase corrosion in the paper machine.
• the temperature difference between the air outside of the modified ER probe and the surface of the ER probe can be control led to be about 3 to 30 C.
• an automatic valve assembly for a cooling water flow can be control led and maintain the probe surface temperature as constant.
• the variation of probe surface temperature can be controlled to be a bout 10 C or less.
• this aspect can be solved by installing an on-line temperature measurement sensor in the modified ER probe.
• a change in the rate of vapor phase corrosion can be considered as valid data when the temperature of the sensor head was unchanged (e.g., a temperature change of about 10 °C or less or about 3 °C or less) from adjacent temperature readings. This provides reliable information on changes in the rate of vapor phase corrosion and this data can be used for adjusting dosages of oxidizing biocides.
• the dosing of oxidizing biocides can be reduced (e.g., nearest to the headbox of the paper machine).
• the signals from the modified E probe and the signals from the temperature sensor are stored in a computer device (e.g., software, hardware, or a combination thereof).
• the computer device can collect, store, and analyze the signals, e.g., rate of vapor phase corrosion and/or change in corrosion quantity is calculated using signals from modified ER probe.
• the computer device can also be used for signals from the temperature sensor, to check val idity of the detected rate of vapor phase corrosion.
• adjustment of the biocide dosing amounts can be determined from the corrosion data (e.g., calculated data or untreated data from the modified ER probe). The adjustment can happen automatically, such as initiated by the computer device, or manual ly, such as initiated by a person.
• the computer device is programmed to send an alarm message for a service person, which after receiving a message of, e.g., increased corrosion rate, can then go and manually adjust biocide dosing quantities to a lower level .
• a computer device monitoring the signals from the modified ER probe and temperature sensor can be used to convert the information on changes in corrosion data (i.e., corrosion quantity or corrosion rate) into relative changes in biocide dosing quantities to the paper making process.
• the system is completely automated.
• the modified ER probe system 200 may be in communication with the computer device 10.
• the temperature sensor 210 and the cooling unit 220, and the modified ER probe 230 may be communication with the computer device 10.
• one or more aspects of the measuring method can be implemented using software and/or hardware as described herein.
• the computing device 10 includes at least one processor circuit, for example, having a processor 13 and a memory 16, both of which are coupled to a local interface 19.
• the computing device 10 may comprise, for example, at least one server computer or like device.
• the local interface 19 may comprise, for example, a data bus with an accompanying address/control bus or other bus structure as can be appreciated.
• Stored in the memory 16 are both data and several components that are executable by the processor 13.
• stored in the memory 16 and executable by the processor 13 are a measuring application 15 and/or other applications.
• Also stored in the memory 16 may be a data store 12 and other data.
• an operating system may be stored in the memory 16 and executable by the processor 13.
• any one of a number of programming languages may be employed such as, for example, C, C++, C#, Objective C, Java , JavaScript , Perl, PHP, Visual Basic , Python , Ruby, Delphi , Flash , MATLAB, or other programming languages.
• executable means a program file that is in a form that can ultimately be run by the processor 13.
• Examples of executable programs may be, for example, a compiled program that can be translated into machine code in a format that can be loaded into a random access portion of the memory 16 and run by the processor 13, source code that may be expressed in proper format such as object code that is capable of being loaded into a random access portion of the memory 16 and executed by the processor 13, or source code that may be interpreted by another executable program to generate instructions in a random access portion of the memory 16 to be executed by the processor 13, etc.
• An executable program may be stored in any portion or component of the memory 16 including, for example, random access memory (RAM), read-only memory (ROM), hard drive, solid-state drive, USB flash drive, memory card, optical disc such as compact disc (CD) or digital versatile disc (DVD), floppy disk, magnetic tape, or other memory components.
• RAM random access memory
• ROM read-only memory
• ROM hard drive
• solid-state drive solid-state drive
• USB flash drive memory card
• optical disc such as compact disc (CD) or digital versatile disc (DVD)
• floppy disk magnetic tape
• the memory 16 is defined herein as including both volatile and nonvolatile memory and data storage components. Volatile components are those that do not retain data values upon loss of power. Nonvolatile components are those that retain data upon a loss of power.
• the memory 16 may comprise, for example, random access memory (RAM), read-only memory (ROM), hard disk drives, solid-state drives, USB flash drives, memory cards accessed via a memory card reader, floppy disks accessed via an associated floppy disk drive, optical discs accessed via an optical disc drive, magnetic tapes accessed via an appropriate tape drive, and/or other memory components, or a combination of any two or more of these memory components.
• the RAM may comprise, for example, static random access memory (SRAM), dynamic random access memory (DRAM), or magnetic random access memory (MRAM) and other such devices.
• the ROM may comprise, for example, a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or other like memory device.
• the processor 13 may represent multiple processors 13 and the memory 16 may represent multiple memories 16 that operate in parallel processing circuits, respectively.
• the local interface 19 may be an appropriate network that facilitates communication between any two of the multiple processors 13, between any processor 13 and any of the memories 16, or between any two of the memories 16, etc.
• the local interface 19 may comprise additional systems designed to coordinate this communication, including, for example, performing load balancing.
• the processor 13 may be of electrical or of some other available construction.
• the measuring application 15 and other various systems described herein may be embodied in software or code executed by general purpose hardware as discussed above, as an alternative the same may also be embodied in dedicated hardware or a combination of software/general purpose hardware and dedicated hardware.
• each can be implemented as a circuit or state machine that employs any one of or a combination of a number of technologies.
• technologies may include, but are not limited to, discrete logic circuits having logic gates for implementing various logic functions upon an application of one or more data signals, application specific integrated circuits having appropriate logic gates, or other components, etc.
• Such technologies are generally well known by those skilled in the art and, consequently, are not described in detail herein.
• a measuring application 15 can be used for monitoring and/or measuring the vapor phase corrosion in a paper or board machine.
• a step 32 includes obtaining information regarding the rate of vapor phase corrosion over a time period.
• the information can be used to determine how to adjust the dosing of an oxidizing biocide in a paper or board making process.
• any logic or application described herein, including the measuring application 15 and/or application(s), that comprises software or code can be embodied in any non- transitory computer-readable medium for use by or in connection with an instruction execution system such as, for example, a processor 13 in a computer system or other system.
• the logic may comprise, for example, statements including instructions and declarations that can be fetched from the computer-readable medium and executed by the instruction execution system.
• a "computer-readable medium" can be any medium that can contain, store, or maintain the logic or application described herein for use by or in connection with the instruction execution system.
• the computer-readable medium can comprise any one of many physical media such as, for example, magnetic, optical, or semiconductor media.
• a suitable computer-readable medium would include, but are not limited to, magnetic tapes, magnetic floppy diskettes, magnetic hard drives, memory cards, solid-state drives, USB flash drives, or optical discs.
• the computer-readable medium may be a random access memory (RAM) including, for example, static random access memory (SRAM) and dynamic random access memory (DRAM), or magnetic random access memory (MRAM).
• the computer- readable medium may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or other type of memory device.
• Example 1 An Electrical Resistance (ER) probe (Roxar Flow Measurements AS, Norway) modified with a cooling unit, with a pt-temperature probe and with a datalogger, was installed in a paper machine making almost 150 000 tons of paper annually. Exact point of installation was in the beginning of the drier section, inside the protective doors of the drier section, in vapor phase, less than one meter away from the paper web.
• the sensing element of the E probe was of carbon steel. Surface temperature of the sensing element was lowered and kept constant, around 60 C, by cooling water flow. Datalogger was recording temperature and rate of corrosion (metal loss) every minute. Datalogger was connected to internet and enabled remote on-line monitoring of the vapor phase corrosion.
• the graph shown in Figure 3 illustrates example data about measured rate of corrosion (metal loss of the sensing element, ⁇ ) during a period from 18 th of December to 3 rd of January. It can be seen from the Figure 3 that until 29 th of December the rate of vapor phase corrosion was quite stable, cumulative metal loss increased linearly and daily average metal loss was ca. 0.3 ⁇ /d. When biocide dosages in the machine were changed after a shut-down of the machine late of Dec 29 th , the on-line probe for vapor phase corrosion responded quickly and showed an increased rate of vapor phase corrosion.
• a modified ER probe (similar setup like in example 1) was installed in vapor phase in beginning of the drier section, near the 6 th cylinder, of a board machine making almost 160 000 tons of packaging board annually.
• Datalogger was recording rate of corrosion (metal loss) every minute.
• Datalogger was connected to internet and enabled remote on-line monitoring of the vapor phase corrosion.
• Figure 4 illustrates a graph that shows example data about measured rate of corrosion (metal loss of the sensing element, ⁇ ) during a five-week period. It can be seen from Figure 4 that during the first ten days the rate of vapor phase corrosion was quite high, with a daily average metal loss of 1.17 ⁇ /d.
• a concentration range of "about 0.1% to about 5%” should be interpreted to include not only the explicitly recited concentration of about 0.1 wt% to about 5 wt%, but also include individual concentrations (e.g., 1%, 2%, 3%, and 4%) and the sub-ranges (e.g., 0.5%, 1.1%, 2.2%, 3.3%, and 4.4%) within the indicated range.
• the term "about” can include traditional rounding according to significant figures of the numerical value.
• Y includes "about 'x' to a bout 'y'".
• a range includes “zero” and is modified by "about” (e.g., about one to zero or about zero to one), about zero can include, 0, 0.1. 0.01, or 0.001.

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