22 SOLENISANDRITZ


Pulp Paper & Logistics


Depending upon the period, it could range from 40 to 70 per cent of the time in the box. Although efforts were made in trying to adjust the chemical dosage as precisely and quickly as possible, these were not enough to guarantee good in-the- box control results. The plant established a few goals


that would enhance the chemical control results and reliability: ● achieve at least 95 per cent of NaPO4 ratio in the control box;


● utilise a state-of-the-art monitoring and control system for boiler water treatment programme;


● have an ability for a remote access control for the programme treatment;


● have the ability to receive alarms for any disturbances;


● minimise manual involvement direct on the boiler water treatment and chemical control. It is important to remember that


any result above 90 per cent of in- box time is considered very good and wanted for most steam generation


systems. This is actually one of the greatest benefits observed after the use of this controller. There was a substantial


improvement on the in-box control. Not only did it become able to have 100 per cent of points in-box, but also it was possible to gather a strong concentration of points very close together. Figure 4 shows the results


before and after application of Knowledge Based Control approach by the OnGuard iController. One can observe that the points repeated many time on the same coordinates, indicating very low variability of the system, independently on the great variations of steam production, feedwater quality upsets and other particular disturbances. After the installation and


operation of Knowledge Based Control equipment, many improvements were observed: ● substantial rise on the in box time, up to 100 per cent; ● very little variability on the


chemistry results for the boiler water;


● high reliability independently of strong steam production variation;


● the plant was able to visualise, monitor and control the system throughout a web based communication;


● less time and availability of manual repairs for the equipment maintenance.


To conclude: Knowledge-based control, using OnGuard iController was able to achieve the following results: ● data bank acquisition and formatting for many different steam production variables (flowrates, pH, phosphate, etc);


● elaboration of predictability strategies for pH and/or steam production variations;


● advanced control with high conversion results on the goals for the boiler water chemistry, not only the congruent phosphate issue.


● larger capacity to absorb contaminations and quality interruptions;


January/February 2018


● deposition and many corrosion mechanisms results warranty in high pressure boilers;


● 100 per cent ‘in the box’ for the sodium phosphate ratio.


*Anderson José Beber BSc is applications project manager at Solenis Especialidades Químicas in Brazil. More information from Solenis Especialidades Químicas. Rua Werner Von Siemens, 111 Torre A Conjunto 11, São Paulo, SP 05069-900, Brazil. Tel: 55 11 3089 9225 (office) 55 479 9186 4948 (mobile). Email: ajbeber@solenis. com


References: 1. Frayne, Colin. ‘Boiler Water Treatment: Principles And Practice’ Chemical Publishing Co. Inc. vol I e II (2002) 2. ‘Drew Principles of Industrial Water Treatment’ Ashland Water Technologies (1986) 3. Amjad, Zahid ‘The Science and Technology of Industrial Water Treatment’, CRC Press (2010) 4. Green, D W Perry, R.H ‘Perry´s Chemical Engineers’ Handbook’ 8th Edition McGraw-Hill (2008)


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