kajaanipolarox Measure and Control Active Bleaching Chemicals kajaani

Transcription

1 kajaanipolarox Measure and Control Active Bleaching Chemicals kajaani

2 Measured Chemical Meas.range [g/l] Cl 2 (chlorine) (chlorine dioxide) ClO - 2 (chlorite) / SO 2 or NaHSO 3 (chlorine dioxide/ sulphur dioxide or sodium bisulfite) / SO 2 (sulphur dioxide) NaOCl (sodium hypochlorite) H 2 O 2 (hydrogen peroxide) OOH - (perhydroxyl ion) Na 2 S 2 O 4 (sodium hydrosulfite) kajaanipolarox Three decades of chemical concentration measurements Polarox FTS circa 1975 Polarox, introduced in the early seventies, has undergone considerable change as bleaching processes, chemicals and control philosophies have evolved. kajaani POLAROXi and kajaanipolaroxfi are fourth generation devices for in-line and on-line chemical concentration measurements. The patented Polarox principle is a key component of the Kajaani dual sensor bleaching control together with the kajaanicormeci brightness sensor in use in hundreds of pulp mills around the world. The kajaanipolarox measures chemical concentrations electrochemically, by means of a multi-electrode system. A set potential, selected according to the chemical being measured, causes a chemical reaction on the measuring electrode. The diffusion current needed to keep this potential constant is directly proportional to the concentration of the chemical. The sensor can use three measurement methods: normal set potential, pulse, or sweep measurements depending on the application and conditions. Today Polarox is finding new applications in the measurement of active bleaching chemicals used in the environmentally friendly conditions of the modern pulp mill.

3 Brightness after P1 tower [% ISO] OOH - Residual after P1 tower [mg/l] :12 8:24 9:36 10:48 12:00 13:12 14:24 15:36 16:48 18:00 19:12 Time [h] kajaanipolaroxi, In-line The kajaanipolaroxi is an all metal electrode sensor inserted through a standard ball valve into a main stock line for fast in-line measurement capability. For use with chemical, mechanical and recycled pulps it provides an accurate and stable measurement in a rugged, easy to install package. The improved electrode design is self cleaning and provides an optional conductivity measurement. Dioxide stages For efficient dioxide stage control, it is important to measure the total chlorine including chlorite. kajaanipolaroxfi with optional graphite electrode can make this measurement shortly after addition. This ensures that sufficient bleaching chemical is available for the whole reaction time without adding excessive amounts. Final pulp quality is improved without compromising environmental conditions or wasting chemicals. Peroxide bleaching For peroxide bleaching control it is not enough to measure the hydrogen peroxide concentration because too many other variables are involved. The Polarox method instead measures the perhydroxyl ion, which is the reactive agent taking part in the oxidative bleaching. The amount of perhydroxyl ion can be effectively controlled with caustic addition controlling bleaching conditions. The result is maximized bleaching effect with optimum chemical applied, very important when emphasizing the environmental aspects of chemical and mechanical pulps. Smooth Follow-up and Maintenance A sure and easy method of tuning has been developed. A valmetnove-h sampling device and tuning button should be installed close to the measuring or sampling point. Laboratory samples can be then easily taken while pressing the tuning button to cause the measurement parameters to be stored in the sensor. The laboratory values can then be loaded later and kajaanipolarox will generate its own correlation curves which are internally stored. Periodic checks can be made in the same manner to ensure accuracy. from digester O2 storage tower MgSO 4 O 2 O 2 O2 O2 D0 H 2 O 2 E/O/P D1 D2 kajaanifiltratepiston, ph kajaanipolaroxfi, ph Kajaani installation is straightforward for all applications and difficult installation points. The same robust installation applies with stainless steel, fiber glass pipe or any other material. Here possible installation points in ECF bleaching.

4 Act. Cl [mg] 600 Tot.act. Cl :30 11:00 11:30 12:00 12:30 Time (h) Total active chlorine in the dioxide stage. kajaanipolaroxfi is an on-line version for measuring chemical concentration in a filtrate sample supplied by the kajaani Filtrate Piston sampling unit. The fiber free filtrate measurement provides the accuracy needed in ECF and TCF process control. The optional ph probe, conductivity measurement and choice of electrode material, sets new standards for ECF and TCF pulp bleaching. Operation All functions are accessible through the COMMUNICATORi graphic terminal used during start-up and calibration. Additionally, BLEACHING TOOLi software can be used with a pc at the connection box, remotely within the mill or through a modem to a Metso service center. BLEACHING TOOLi is a sophisticated modeling tool for calibration, diagnostics and signal trending of all sensors (also kajaani- CORMECi) connect to MODBUS. kajaani Filtrate Piston The kajaani Filtrate Piston is a reliable piston type sampler developed by Metso for obtaining fiber free samples in chemical pulp bleaching. As well as providing a suitable sample for the kajaanipolaroxfi, it can be used for any measurement needing filtrate samples such as ph and conductivity or for manual laboratory analyses. No high pressure water or air is required, the sampler is kept clean by the actuator driven piston (patented). Easy & Safe Installation kajaanipolaroxi and the kajaani Filtrate Piston for kajaanipolaroxfi both use the tried and proven installation through a standard NS50 ball valve with bolted flanges and safety chain secured. They can be inserted and withdrawn safely without process interruption using the optional mounting tool. The sensor depth in the process can be freely adjusted to ensure that the measurement electrodes are always in the continuous pulp flow.

5 Specifications Applications Measurements Temperature ph Conductivity Process Conditions Process pressure Process temperature Ambient temperature Ambient temperature of Communicator-i Recycled fiber, Mechanical & Chemical pulping and Paper & Board Machines Active bleaching chemicals C ( F) ph 0-14 (option) ms/m (option) max kpa (16 bar, 232 psi) C ( F) 0-55 C( F) 0-50 C ( F) Materials Sensor Titan or Acid-proof steel AISI 316 Sensor shield Titan or Acid-proof steel AISI 316 Packing-valve module FEP-coating, epoxy-painted cast iron GGG40.3 orss, FEP-coating, AISI 316 T-piece* Titan or Acid-proof steel AISI 316 Installation flange* DN50 (proven safe standard) or ANSI Pound T-piece pipe* ANSI 2 Schedule 40 * fabricated by customer Enclosure Class Sensor IP 65 (NEMA 9) Communicator-i IP 64 Operating Voltage Sensor Communicator-i Connections Analog outputs Binary outputs Tuning button interface Serial communication VDC/15 W or VAC/ A/45-65 Hz/50 W VDC/5 W, power supplied from Connection Box 4 outputs, 4-20 ma, isolated 1 output, Relay / 48 VDC/0.5 A 1 Binary input, 1 Binary output RS-232 PC-connection RS-485 Communicator RS-485 MODBUS (detailed info on request) Dimensions Length of sensor 830 mm (32 11 / 16 ) Diameter of sensor head 38 mm (1 1 / 2 ) Sensor housing (h x w x d) 285 x 350 x 140 mm (11 7 / 32 x / 32 x 5 33 / 64 ) Connection box (h x w x d) 300 x 250 x 150 mm (11 13 / 16 x 9 27 / 32 x 5 29 / 32 ) Communicator-i (h x w x d) 180 x 198 x 40 mm (6 5 / 16 x 7 51 / 64 x 1 37 / 64 ) Weights Sensor titan Sensor AISI Packing-valve module Sensor shield Connection box Communicator-i 11.5 kg (25.6 lbs) 12.0 kg (26.5 lbs) 15.5 kg (34.2 lbs) 1.2 kg (2.6 lbs) 5.7 kg (12.7 lbs) 1.4 kg (3.1 lbs)

6 Metso Automation Field Systems Kehräämöntie 3, P.O. Box 177 FIN Kajaani Finland Tel Fax Europe Levytie 6, P.O. Box 310 FIN Helsinki Finland Tel Fax North America 3100 Medlock Bridge Road, Suite 250 Norcross, GA USA Tel Fax Latin America Av. Central 181, Chácaras Reunidas São José dos Campos SP Brazil Tel Fax kajaanipolaroxi basic delivery includes the sensor, packing valve module, and connection box with sensor cables. kajaanipolaroxfi basic delivery includes the sensor and connection box with optional kajaani Filtrate Piston. Communicator-i with graphical user interface is optional as well as tuning button. Bleaching Tool-i enables communication between PC and sensor/server-i, for configuration, data collection, and operation monitoring. Mounting Tool is a recommended option especially with higher process pressures. Asia Pacific 501 Orchard Road #05-09 Wheelock Place Singapore Tel Fax B EN Metso Automation 03/2003. Subject to change without prior notice.