Size & Defoamer (S&D) & Pulping Aids
Size & Defoamer (S&D) & Pulping Aids
The Centre of Excellence involved in the sizing and defoaming / de-aeration (anti foaming) in the Pulp and Paper & Tissue Industry, Chemi-SizDe, consists of experienced, dedicated and focussed individuals who aim to bring solutions and innovation to the customer.
As part of Chemi-SizDe, Defoamer and / or Anti foaming forms an integral part in the efficiency of the various processes where it is being applied. Many processes in the pulp, paper and tissue industry have the need for a product to kill existing foam for housekeeping and process purposes and / or de-aerate process stock for improved process performance.
Defoamer products had simple beginnings when kerosene and fuel oils were used. Today it has become specialised and in many applications tailor made for a specific process, using silica, oil and water emulsions geared towards a specific application.
The formation of foam is dependant on entrained air brought along via some form of agitation, air entrapment or dissolved gas caused by pressurized systems in the process fluid. Coupled to the mechanical and physical effect there is also the chemical effect comprising of surface acting agents found in the process, which are either non ionic, anionic, cationic or amphoteric. Put together, these can become serious headaches for the industry affecting everything from simple housekeeping via overflowing tanks, weirs or ponds to actual process efficiency impacting on drainage of forming section wires, pulp plant washers, and even carry over in evaporator sets, thus fowling the condensate.
Some defoamers are quick acting at the point of the affected area, impacting primarily on the surface foam formed and not do much for de-aeration, like the hydrocarbon oil based emulsions, while others might be slower acting on the initial surface foam, but impacting primarily the air inside the process fluid and in so prevent downstream regeneration of foam like some water based and silica containing emulsions.
While a defoamer may work very well in one process, it may not perform well at all in another. This is where the Centre of Excellence comes in. We evaluate your process using various available samples to see which is the most effective in its efficiency as well as cost. If no single defoamer indicates any benefit, a more tailor made defoamer can be researched and formulated for your specific process. Coupled to this, the evaluation of entrained air where possible and practical in the process, gives us a better understanding of where the origin of the problem might be.
We currently supply defoamers in the pulp, paper, tissue and cement industry.
Chemi-SizDe, your specialist in sizing and defoaming.
As one of the leading suppliers of chemicals to the paper industry, we never stop in our efforts to develop and improve our products and processes. Therefore Chemisphere Paper Technologies use sizing technology from our technology partner Ashland Hercules. They are a leader in all forms of sizing technology to the Paper and Board Industry.
Chemisphere Paper Technologies goal is to satisfy your current needs, address emerging markets, and foresee new finished product characteristics. Here are some of the current applications and areas in which Ashland sizing technology works to improve the paper and papermaking process:
If your system is based on an acid to pseudo neutral pH, our rosin-based technologies would work well for paper, board, and aseptic packaging grades. Depending on your paper requirements, we provide a variety of rosin-based soap and dispersed size technologies. Whether you run with a negative or positive charge, our dispersed technology includes anionic, using alum to pull the size to the fibres in the dryer section, or cationic, with greater sizing efficiency that doesn’t require as much alum to attract the size to the fibres.
Rosin based sizing products are manufactured in South Africa, to ensure optimal value for money to the end user.
Internal Size—Reactive AKD,ASA
For systems that run an alkaline pH, we offer cellulose-reactive alternatives as ready-to-use emulsions or concentrated liquids that are emulsified at the point of use. Ready-to-use emulsion reactive sizes provide:
• High ultimate sizing
• Ease of use/convenience
• Improved paper machine run ability
• Machine cleanliness
Liquid reactive size is designed for commodity printing papers, recycled linerboard, and specialty applications. This technology allows the production of precision-converted grades: forms bond, cut-size, and envelope.
Ashland’s surface treatment products are capable of meeting the papermakers’ needs for sizing, printability, toner adhesion, coefficient-of-friction control, porosity improvement, surface strength, and offset and inkjet print performance. For printing papers, this technology offers product options for reducing fibre wet-ability at the radius of the pores or capillaries, making liquid penetration more difficult. For the inkjet and print-on-demand market, some surface hydrophobic treatment is required to prevent the inks from completely penetrating the sheet, while additional surface structure is required to prevent the inks from bleeding together. Balanced with internal sizing, ink holdout and ink absorbency can be tailored to fit the end use.
Ashland provides two technologies specific to different surface sizing requirements: solutions and emulsions. Solutions are effective for preventing liquid penetration, whilst the emulsions help with better printability. Other advantages seen with Ashland’s surface size technology, impacting machine performance, production costs, and sheet quality include:
• Less dependency on internal size for runnability across the paper machine
• More treatment options and quicker grade changes at the size press
• Flexibility to use harder-to-size pulp furnishes
• Cleaner-running, deposit-free machines
• Development of new grades
For further information please contact:
Lance Dell - Divisional Manager
Tel: 27 (0) 32 456 2904
Fax: 27 (0) 32 456 2906
Moblile: 27 (0) 83 305 9375