Industry Newsletter Process 3 - Mettler Toledo€¦ · their plant in Yingkou City, Liaoning...

3News

ProcessPerspectives in Liquid Process Analytics

INGOLDLeading Process Analytics

THORNTONLeading Pure Water Analytics

80%ReductioninSensorMaintenancewith Process Tolerant pH Electrode Inchlor-alkaliprocesses,maximizingproductivityishamperedbythe

unreliability,highmaintenancedemand,andshortlifetimeoftraditional

pH probes. For a Sino-German chemical company, a pH electrode

designedspecificallyforchlor-alkaliusehasreducedsensormaintenance

toaminimum.

ImportantcompoundCyanuric chloride is used as an intermedi-ate in the manufacture of pesticides, dyestuffs, optical brighteners, and phar-maceuticals. More than 100,000 tonnes of the compound are manufactured annually.

The world’s largest producer is Evonik Industries Group, Germany’s third largest chemical company. Evonik Industries Fine Chemicals Co., Ltd. is a Sino-German joint venture set up between Evonik and Yingkou Sanzheng Fine Chemical Co. At their plant in Yingkou City, Liaoning Province, China they produce cyanuric chloride as well as the main raw materials for its production: sodium cyanide and chlorine.

pHcontrolisessentialinchlor-alkaliprocessesIn respect of chlorine production, Evonik employs the membrane cell chlor-alkali process. Here, aqueous sodium chloride (brine) is electrolyzed in large cells to produce chlorine gas at the anode and, as co-products, caustic soda and hydrogen at the cathode. Anode and cathode are sepa-rated by an ion-exchange membrane that prevents the chlorine being reduced by the hydrogen and forming chloride and hypo-chlorite ions.

pH value is extremely important in a number of steps throughout the mem-brane cell process. Purity of the brine entering the electrolysis cells has a great bearing on process yield. By adding vari-ous salts as precipitants and increasing the

2 METTLERTOLEDOProcess News 3

InPro 4850 i pH electrode

pH to between 10 and 12, impurities such as sulfates and metal hydroxides can be extracted. On the anode side of the cells the reaction takes place under acidic conditions (pH 3 – 4). Although a lower pH would improve yield, it would damage the cell membrane, which are expensive to replace. The depleted brine that leaves the cells contains chlorate. Through a de-struction process at pH 2, the chlorate is converted to chlorine and extracted.

pHelectrodeexplicitlyforchlor-alkaliuseThe diaphragm on the electrodes that Evonik was using for pH monitoring were being clogged by brine crystals, necessitat-ing regular and time-consuming sensor cleaning and calibration. In addition, chlorine was diffusing through the dia-phragm, affecting measurement reliabil-ity and reducing sensor lifetime. Evonik engineers were anxious to find a reliable, low-maintenance system that would not suffer from these issues. On one of the

cells, METTLER TOLEDO installed a test system using our InPro 4850 i, an elec-trode developed specifically for use in chlor-alkli processes. A number of fea-tures make it the ideal choice.

Dual-membraneelectrodeThe sensor features two separate glass membranes. The first is a sodium-sensitive membrane which is charged by the sodium ions in the brine. As the sodium concentration in chlor-alkali electrolysis cells remains fairly constant, the InPro 4850 i uses the brine as a reference. The second glass membrane is sensitive to pH and operates in the same way as those found on most pH electrodes. By measur-ing the difference between the potentials of the two glass membranes, the pH of the solution can be accurately determined.

The sodium reference system is hermeti-cally sealed; there is no diaphragm, therefore the possibility of sensor clogging and poisoning, and the consequent need for frequent cleaning and calibration, is eliminated.

DigitalsignalOther dual-membrane sodium / pH elec-trodes are available, but they suffer greatly from electrical interference. Combined, the two glass membranes have a very high impedance. With the added impedance of the cable between the sensor and trans-mitter, touching or simply approaching the system can create a change in the output measurement. And the longer the cable, the worse the effect.

The InPro 4850 i communicates digitally with its transmitter. Being digital, the output signal from the sensor is always 100 % stable and arrives at the transmitter unaffected by electrical interference, cable length, or moisture in the environment.

IntelligentSensorManagementThe InPro 4850 i is one of METTLER TOLEDO’s Intelligent Sensor Management (ISM) sensors. All ISM sensors transmit a digitized signal to ISM transmitters; how-ever, digital communication is not the only advantage of ISM technology. Plug and Measure functionality provides fast and simple measurement point start-up. Advanced predictive diagnostics tools offer real-time data on sensor “health” so that any corrective actions can be made before measurements are affected.

SubstantialdropinmaintenanceThe test system at Evonik operated very successfully. The combination of the process-tolerant dual-membrane design, and digital signal and other features of Intelligent Sensor Management reduced sensor maintenance by around 80 %, and has also improved process performance. Such is Evonik’s satisfaction that they are planning to replace all their existing chlor-alkali pH electrodes with the InPro 4850 i.

Find out more about the InPro 4850 i at:cwww.mt.com/InPro4850

Publisher/ProductionMettler-Toledo AG

Process Analytics

Im Hackacker 15

CH-8902 Urdorf

Switzerland

IllustrationsMettler-Toledo AG

Jklune, Robeo | Dreamstime.com

Sapsiwai, JohnCarnemolla |

iStockphoto.com

Subject to technical changes.

© Mettler-Toledo AG 01/13.

Printed in Switzerland.

METTLERTOLEDOProcess News 3 3

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circuit as well, especially in nuclear plants. With conventional sensors and instruments, the measuring circuit must be calibrated against a series of precision resistors covering the range of measure-ment. METTLER TOLEDO Thornton has provided calibration modules containing all of these resistances, conveniently packaged and with traceable, certified accuracy.

CalibratewithoutremovingthesensorWith new digital UniCond sensors, the measuring circuit is built into the sensor and calibration of the measuring circuit is also performed on the sensor. The pro-cedure and UniCond calibrator, with switch-selectable precision resistors, sup-ports this capability, with readout of re-

sults at the transmitter. In fact the mea-suring system even allows electronics calibration with the sensor still immersed in the sample.

Once the measuring circuits for conduc-tivity and temperature are calibrated, then the complete sensor, including cell con-stant and temperature sensor, are cali-brated based on a standard conductivity solution or by comparison with a certified reference instrument measuring the same sample. The temperature is calibrated by comparison with a standard temperature device.

UniCond sensors provide a definite step up in performance compared with previous generations of conductivity sensors.

For more information go to:cwww.mt.com/unicond

Whyisaccuracyimportant?Conductivity is one of the best methods to detect ionic contamination in a makeup water treatment system. As a result its ability to repeatedly and accurately detect low levels of ionic contamination is criti-cal in power plant water chemistry. Ultra-pure water has a conductivity of 0.055 µS /cm at 25 °C; therefore, conductivity instru-ments must have the ability to accurately and repeatedly detect very small conduc-tivity changes with a non-zero background.

CalibrationoptionsThe ability of makeup water system fabri-cators to produce water with lower ionic concentrations and the demand to reduce costs has benefitted from the introduction of a new generation of conductivity instru-ments. Today’s digital transmitters and sensors are more accurate, are easier to operate, and provide more control over the water system than ever before. The METTLER TOLEDO Thornton UniCond sensor measures an expanded conductiv-ity range from seawater to ultrapure water (0.02 – 50,000 µS / cm) and with up to 33 % higher accuracy than analog sensors. To supplement this, a unique calibration module provides simplified calibration of the internal measuring circuit without removing the sensor from the process.

SimpletousecalibratorCalibration practice in most plants re-quires at least annual calibration of con-ductivity sensors and often the measuring

SimpleConductivitySensorCalibrationCalibrator Helps Ensure AccuracyUniCond®conductivitysensorshaveaverywidemeasurementrange–

fromseawatertoultrapurewater–makingthesamemodelofsensor

suitable for a wide variety of applications. Now, UniCond has been

improvedfurtherwithatoolthatallowscalibrationwithoutremovingthe

sensorfromtheprocess.


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rs IncreasedProductionUptimeThanks to High-performance DO SystemDissolved oxygen in parenteral solutions can oxidize the products,

rendering them unusable. For a Spanish producer, METTLER TOLEDO

systemsnotonlyreliablymonitorDOdowntotracelevels,theyhavealso

ledtogreaterproductivity.

ImportanceofinertatmosphereParenteral nutrition solutions typically contain a significant percentage of amino acids and vitamins. During production and dispensing, exposure to oxygen and UV light must be kept to a minimum to prevent product oxidation. For this reason, nitrogen-inerted stirred vessels are em-ployed in the production area. Measuring dissolved oxygen (DO) in the process fluid allows production technicians to monitor and control inerting efficiency. After pro-duction, the parenteral solution, which has a very low DO content, is transferred to the most critical element in the produc-tion chain, the dispenser.

RapidproductdetectionpreventsproductlossThe engineering division designed and built the dispensing unit with the aim of achieving better quality and safety levels than those possible with equipment avail-able on the market. The stainless-steel dispenser has a production capacity of up to 3,000 units / hour using bags from 50 to 1000 ml. In order to minimize the pos-sibility of contamination, purified water flows through the dispenser between pro-duction runs. To prevent product loss during filling, sensors that can rapidly measure trace levels of oxygen are re-quired to quickly identify when pure product has reached the filling tubes.

Highly-robustDOsensorsIn respect of DO monitoring in these processes, the company requirements were for fast responding, extremely reliable sensors that would tolerate CIP cycles. METTLER TOLEDO provided the solutions.

For use with the production reactors, the InPro 6800 DO sensor and M400 transmitter were selected. The InPro 6800 is CIP, steam sterilization, and autoclav-ing tolerant, and features a hygienically polished surface finish and rugged PTFE-coated membrane. Its detection limit of 6 ppb ensures failure of the inerting system is quickly identified.

ParenteralsolutionsproducerOur customer is a Spain-based, multi-national pharmaceutical and chemical company. It is a major supplier of intrave-nous immunoglobulin, albumin, and Factor VIII as well as other products and various services to hospitals, pharmacies, and healthcare professionals across the globe.

At their production plant in Spain, the company produces parenteral nutrition solutions which it supplies in flexible polypropylene bags. In order to increase production capacity and reduce costs, the company commissioned their own engi-neering division to design and implement a fully-automatic dispensing line to be added to the production area which was also designed by their engineering division.

InPro 6800 dissolved oxygen sensor

InPro 6970 i optical dissolved oxygen sensor


FlexibletransmitterThe M400 single-channel, multi-parame-ter transmitter features a mixed-mode input for the connection of conventional analog or METTLER TOLEDO’s digital Intelligent Sensor Management (ISM) probes.

ISM significantly simplifies sensor han-dling and maintenance, and increases process safety. It achieves this via a range of features including Plug and Measure for fast measurement point start up, and predictive diagnostics that tell the user when sensor maintenance will be required.

Intelligentsolutionmonitorssensor“health”The ISM-equipped InPro 6970 i sensor with the M400 transmitter was chosen for trace-level DO monitoring at the dispenser filling line. Here, ISM’s predictive diag-nostics tools provide technicians with real-time information on sensor “health”, allowing the probes to be maintained at peak operating efficiency, and minimiz-ing the possibility of production downtime due to sensor failure.

The InPro 6970 i is one of METTLER TOLEDO’s growing range of optical oxy-gen sensors. Optical measurement tech-nology offers fast response and very low drift, making the InPro 6970 i highly suitable for this particular application.

IncreasedproductionOur customer is very satisfied with the performance and durability of the DO sensors. But in particular, they are pleased with the benefits ISM gives them. Plug and Measure combined with predictive diag-nostics has led to higher than anticipated production uptime, helping them meet demand for their parenteral solutions.

Find out more about our DO sensors at:cwww.mt.com/DO

M400 transmitter


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Industry Advisory Group to the Interna-tional Cyanide Management Institute. All of Cyanco’s facilities are ICMC certified.

HazardousprocessThe precursor to sodium cyanide, hydro-gen cyanide, is produced by Cyanco using the Andrussow oxidation process, in which methane and ammonia react in the pres-ence of oxygen over a platinum catalyst. pH is used to monitor and adjust final cyanide product levels for optimal reaction in gold extraction.

Maintenance of pH electrodes used in the hydrogen cyanide process is a time-con-suming and dangerous procedure and requires full donning of Personal Protec-tive Equipment (PPE) including respira-tors, to protect operators from cyanide poisoning.

CalibrationinasafeenvironmentCyanco had been using METTLER TOLEDO̓s InPro 4260 pH electrodes and 2100 e transmitters successfully for many years, but is always interested in advances in analytical measurement technology that can improve its product quality and, more importantly, protect employees’ health.

For this reason, Cyanco has made the transition from the above mentioned system to one comprising an M400 trans-mitter and InPro 4260 i electrodes. The “i” in the sensor’s name denotes that it features METTLER TOLEDO’s Intelligent Sensor Management (ISM) technology. ISM-equipped sensors carry a micropro-cessor in the sensor head that allows a number of very valuable features. For Cy-anco, the most important of these is the ability to calibrate sensors away from the process in a safe environment. Using standard pH buffers and a USB cable con-nected to a PC running iSense Asset Suite software, Cyanco technicians are able to accurately calibrate the InPro 4260 i in a lab where PPE is not required.

LeadingsodiumcyanideproducerDespite their toxicity, cyanides are widely used in the manufacture of many com-mon everyday goods including vitamins, cosmetics, and even table salt. It goes without saying that production of cyanides must be carried out under very strict con-ditions to protect staff and the environment.

Sodium cyanide is used during the elec-troplating of precious metals. Cyanco is the leading supplier of sodium cyanide to the gold mining industry in the United States and Canada. In addition to two plants in Nevada, the company operates a terminal at Cadillac, Quebec to serve customers in the growing market in East-ern Canada. Cyanco has been a leader in the development and implementation of the International Cyanide Management Code (ICMC) and is represented on the

SaferCyanideProductionDigital Sensor Technology Reduces RisksSodiumcyanideisanimportantcompoundforthegoldminingindustry.

Butthehazardousproductionenvironmentmeanspersonnelexposure

time must be minimal. Thanks to METTLER TOLEDO technology, pH

electrodeexchangeonlytakesaminute.

InPro 4260 i pH electrode

M400 transmitter


Fast,simplesensorexchangeWhen electrode exchange is needed, an operator wearing PPE takes a pre-cali-brated probe into the production area, removes the old electrode and connects the pre-calibrated one. The Ex-approved M400 transmitter immediately recognizes the electrode and configures itself accord-ingly. This Plug and Measure feature means the system is ready to measure in a matter of moments and operators can leave the production area having spent a fraction of the time there that they did when the non-ISM systems were in use.

PredictivemaintenanceSensor calibration is not the only feature of ISM that attracted Cyanco. ISM systems incorporate advanced predictive diagnos-tics tools that are displayed on the M400 transmitter and iSense software. These tools inform operators when sensors will need cleaning, calibration or exchange. This allows maintenance to shift from a regularly scheduled or reactive process, to one where tasks can be planned in ad-vance. This ensures that the electrodes in use are maintained at peak operating condition, safeguarding process reliability and product quality.

Additionally, to simplify the control process, Cyanco plans to implement the PID control on the M400 in the near future for acid and caustic feeding during production.

LoweroperatingcostsThe switch to ISM technology has reduced operator exposure to a hazardous environ-ment and improved production processes, resulting in greater operational safety and significant cost savings.

If you want to improve safety and reduce costs at your plant, go to:cwww.mt.com/ISM

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GreaterPlantSafetyataReducedCostThanks to In Situ Oxygen MonitoringThepotentialforexplosionsduringtheproductionofdyeintermediates

necessitates strict oxygen control. High-performance systems from

METTLERTOLEDOgiveaChineseproducer improvedoperatingsafety

andmoreefficientproduction,plusloweroperatingcosts.

Close attention is paid to ensuring produc-tion is safe for plant employees as well as being environmentally friendly.

InertatmosphereisrequiredAt the plant, the production of dye inter-mediates involves the reaction of poten-tially explosive substances. To minimize the risk of explosive conditions developing, empty reactor vessels are inerted with ni-trogen to an oxygen level of less than 5 %

Vol. before process materials are injected. Throughout the inerting and reaction processes, sensors monitor the oxygen level in the reactors.

Plant engineers used locally produced oxygen monitoring systems but found that the sensors could not tolerate the 60 °C temperature and 5 bar pressure conditions and had to be regularly replaced. In addi-tion, the deployed transmitters could not

AdvancedproductionfacilityIn 2006, three Chinese chemical produc-ers, Zhejiang Dibang Chemical Co., Ltd. Zhejiang Runtu Corporation and the Zimmer Chemical Group Co., Ltd. jointly developed a plant for the production of dyes and dye intermediates.

Located in China’s Zhejiang province, the facility uses state-of-the-art production equipment and manufacturing processes.


be configured with pressure compensa-tion. Because of this failing, engineers were never certain of the O2 level in the reactors and would continue to feed nitro-gen to the vessels without knowing if it was necessary.

Time spent on maintaining the oxygen measurement systems and preserving inert conditions in the reactors meant engineers could not concentrate on more skill-intensive tasks.

DurableoxygenmeasurementsystemsMETTLER TOLEDO was asked to provide a solution that would meet all the require-ments of condition tolerance, and would also allow pressure and temperature compensation. Four systems using InPro 6800 G oxygen sensors were in-stalled on the reactors.

As these sensors do not require any gas sampling or conditioning equipment, they were mounted within the reactors’ head-space, directly where the vital measure-ments are required. The InPro 6800 G is designed to operate reliably in tempera-tures up to 70 °C and pressures up to 9 bar, and is immune to the presence of water vapor. The occasionally required replace-ment of the sensor’s membrane body is a simple task that can be achieved in a few minutes.

A further benefit of the sensor is that it can be calibrated in air, negating the need for costly calibration gases. Automatic tem-perature and pressure compensation in the partnering METTLER TOLEDO trans-mitter provides assurance of accurate measurements on the display at all times.

SecureproductionenvironmentImplementing the METTLER TOLEDO solution has resulted in a significant drop in part replacement, maintenance costs, and nitrogen use. More importantly, plant

safety and production efficiency have been improved. According to Mr. Weiping Qin, Engineering Department Manager at the facility, “Installation of the METTLER TOLEDO systems means a more secure production environment and lets us focus more on the production process.”

If you need to maintain inert conditions at your facility, go to:cwww.mt.com/o2-gas

InPro 6800 G oxygen sensor

Freeguidetopro-cessanalyticsinthechemicalindustry

Our new eBooklet is full of success stories on how our customers solved their ana-lytical measurement chal-lenges.

Get the guide at:cwww.mt.com/pro-chem-ebook

Best Practice


New Products for the Power Industry

NewpHureSensor™OptionMeasuresHighPurityWater

Provides high accuracy in low conductivity water for power plant applications. The new METTLER TOLEDO Thornton pHure Sensor increases pH measurement accuracy for higher performance in low conductivity water samples. Proper pH measurement and adjustment helps prevent scale and corrosion in boiler feedwater.

Featuresandbenefits:j Enables high accuracy pH measurement in low conductivity samplesj Free flowing junction operates by gravity without external pressurizationj Provides convenient buffer containers to hold electrode during

calibrationj Uses a single probe electrode with very low-volume housing to

prevent corrosion product particles from accumulating and slowing response

cwww.mt.com/pHure

OpticalDissolvedOxygenSensorMonitorsUltrapureWaterOffers significant enhancement with simplified maintenance and faster response. Optical Dissolved Oxygen (ODO) sensors are used to monitor pure water in cycle chemistry applications. METTLER TOLEDO Thornton ODO sensors offer reduced maintenance – no electrolyte exchange or sensor polarization is required.

RecommendedmeasurementpointsjDeaerator outlet to monitor performance efficiency:

DO range 0 – 10 ppbjFeedwater with oxygenated treatment – controls

passivation: DO range 50 – 100 ppbjFeedwater heaters - optional to confirm satisfac-

tory control within target regime.jCondensate to detect air in-leakage:

DO range 0 – 20 ppbjStator cooling to minimize copper cor-

rosion: DO range 0 – 20 ppb or 0 – 5 ppm

Featuresandbenefitsj In generator cooling ODO is not susceptible to dissolved hy-

drogen interferencejReduced maintenance – no electrolyte exchange or sensor polarization for en-

hanced stabilityj Fast response time

cwww.mt.com/DO


GPr

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nsor OxygenAnalysisMadeEasy

with Powerful In-line TDL Sensors

Whenitcomestoprocesssafetyforprotectingtheenvironment,people,

andassets,onlythebestequipmentwilldo.METTLERTOLEDO’snewO2

solutionofferstheconvenienceandeaseofuseofanin-linesensor,and

theperformanceofapowerfulgasanalyzer.WiththeGPro™500,oxygen

measurementissimplerandmorereliablethaneverbefore.

Tunable Diode Laser (TDL) gas ana-lyzers are a significant improvement over extractive analysis systems. METTLER TOLEDO has combined TDL technology with our long-standing expertise in industrial application analytical instrument

design. The result is a probe that delivers the convenience of an in-line sensor and the level of measurement performance of a top-line analyzer.

Find out more at:cwww.mt.com/o2-TDL

METTLER TOLEDO’s GPro 500 repre-sents a revolution in oxygen sensors. Packed with state-of-the-art technology it offers exceptional measuring performance and easy installation, and requires little or no maintenance.

Your benefits

SimpleinstallationOther TDL sensors are of a cross-stack design that causes installation difficul-ties. GPro 500 needs only one flange and no alignment.

MinimalmaintenanceOther than yearly verification and occa-sional cleaning of the optics, no other maintenance is necessary.

NosampleextractionorconditioningrequiredGPro 500 measures in situ and does not require costly and breakdown-prone sam-pling equipment.


GPro 500 TDL oxygen sensor

Get in-line with METTLER TOLEDO

EasySensorCalibrationwith Free Maintenance SoftwareIntelligentSensorManagement(ISM)ishelpingtoimproveproductivityinprocessindustrycompaniestheworldover.

iSense Asset Suite, the partnering software for ISM sensors, allows easy sensor calibration in a convenient location away from the process, sensor diagnostics for increased process uptime, traceability over a sensor's lifetime, and much more.

A free version of iSense, iSenseLight, has all the main features of the full software. No license is required and there is no need for registration.

With iSenseLight, ISM sensors and transmitter, and an iLink USB cable you immediately get all these benefits:

j Fast and easy sensor calibration in a convenient location j Predictive maintenance diagnosticsj Configuration of optical oxygen sensors j Printable calibration reports

cwww.mt.com/iSenseLight

Visit for more informationwww.mt.com/proMettler-ToledoAG

Process AnalyticsIm Hackacker 15CH-8902 UrdorfSwitzerland

Industry Newsletter Process 3 - Mettler Toledo€¦ · their plant in Yingkou City, Liaoning...

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