In chemical pulping, wood chips are cooked in chemicals until the lignin dissolves and releases the wood fibres. The dominant chemical pulping process is the Kraft process, which gives a dark brown pulp caused by lignin residues. Before it can be used for the manufacture of fine paper grades, this dark pulp must undergo a bleaching process. Conventionally, chlorine or chlorine compounds have been used as the bleaching agent, but these result in an effluent containing chlorinated organic compounds and chlorates that are harmful to the environment and are a growing concern. Oxygen bleaching can be used as an alternative to make papers that are totally chlorine-free. As regards paper recycling, the current deinking methods used in recovering pulp from materials such as mixed office waste (MOW) mostly involve a kind of extraction process under alkaline conditions.
All such traditional processes mentioned above either involves lot of chemical use or high consumption of energy. This causes damage to the environment, depletion of natural resources and increased processing cost. The cost effective alternate to above is the ENZYMATIC PRODUCTS AND PROCESSES.
Bleach Boosting
Treating Kraft / Virgin pulp with certain enzymes (xylanases) opens up the hemicellulose structure containing bound lignin and facilitates the removal of residual lignin prior to bleaching. By using selected xylanases, it is possible to obtain a partial hydrolysis of the hemicellulose precipitated onto pulp fiber during the alkaline cooking process. Enzyme treatment has two indirect effects – firstly, it is possible to wash out more lignin from the pulp, and secondly, the pulp becomes more susceptible to bleaching chemicals. This technique is called 'bleach boosting' and significantly reduces the need for chemicals in the subsequent bleaching stage. In addition, it is easier to remove the residual lignin by treating pulp with enzymes prior to bleaching using traditional chemicals. Xylanases thus help to achieve the desired level of brightness of the finished pulp using less chlorine.
Products:
SEBRITE BLEACH
AESL has designed SEBRITE BLEACH - a bleach boosting enzyme based solution which can be used universally on all kinds of Pulp. The uniqueness of these products lines in its high resistance to alkaline pH (can withstand upto pH of 10) and temperature (can be used upto temperature of 90 0C). Sebrite Bleach is a powder based thermo-tolerant enzyme formulation design for virgin pulp bleaching. It cleavages the L-C bonds in unbleached pulp and solublizes the hemicelluloses and lignin. During chemical bleaching reduces the chemical consumption and increase the final brightness of bleached pulp. Enzyme treatment also reduces the COD, BOD COLOR and AOX in bleach plant effluent
The main benefits for mills using SEBRITE BLEACH for bleach boosting are:
• Reduction in Kappa number
• Savings in bleaching chemicals
• Increased final brightness
• Increased production capacity for mills limited by bleaching capacity
• Reduced AOX levels in mill effluents
• Improved fiber properties
SEBRITE B3: SEBRITE B3 is alkali stable enzyme preparation intended for use in bio-bleaching of pulp. It is thermostable and has a property of enhancing the bleaching of wood, agriculture waste pulp under specified processing conditions.
Pulping is a process by which wood chips converted in to fibrous mass. The task accomplished by chemically or mechanically or applying the combination of both. In mechanical pulping process the yield is very high up to 95% but require high energy. While, chemical pulping process about 80% lignin, 50% hemicelluloses and 10% cellulose dissolves from wood so that the yield is very low as 40-50% but increases the pollution load. A chemical base additive such as Anthraquinone (AQ) is carcinogenic in nature. Enzyme based pulping additive SEBRITE-CAD increase the swelling and porosity of wood chips for easy penetration of liquor. It looses the cellulose fiber by breaking the chemical bonds between lignin, hemicelluloses and cellulose. It enhances the penetration of pulping liquor in to wood chips, protect the cellulose fiber and help to selectively dissolve the lignin. Thus, our enzyme preparation increases the yield and quality of cellulose fiber at lower chemical dose or in lower reaction time. In mechanical pulping, swelled wood chips require less mechanical action to disintegrate and subsequently enzyme treatment lowers the energy consumption.
Products:
SEBRITE CAD: is a bio-based pulping additive. It enhances the swelling of wood chips and subsequently penetration of cooking liquor by diffusion.
Surfactants are wetting agents that lower the surface tension of a liquid, allowing easier spreading, and lower the interfacial tension between two liquids.
The term surfactant is originated from the word “surface active agent”. These are generally organic compounds and amphiphilic, in nature. Therefore, they are soluble in both organic solvents and water.
In the waste paper deinking process, Surfactants reduce the surface tension of water by adsorbing at the liquid-gas interface. Thus help to detach the ink particle from cellulose fiber.
Many surfactants can also assemble in the bulk solution into aggregates. Examples of such aggregates are vesicles and micelles. The concentration at which surfactants begin to form micelles is known as the Critical Micelle Concentration or CMC. When micelles form in water, their tails form a core that can encapsulate an oil droplet, and their (ionic/polar) heads form an outer shell that maintains favorable contact with water. When surfactants assemble in oil, the aggregate is referred to as a reverse micelle. In a reverse micelle, the heads are in the core and the tails maintain favorable contact with oil. Surfactants are also often classified into four primary groups; anionic, cationic, non-ionic, and zwitter ionic (dual charge).
Products:
SEBRITE 0101S: is a unique blend of enzymes and chemicals based on biosources. It facilitates the better removal of ink along with Sebrite DI in the deinking cell or by washing deinking.
SEBRITE 0102S: is a unique blend of chemicals based on natural sources. It facilitates the better removal of ink along with Sebrite DI in the deinking cell or by washing deinking.
SEBRITE 0103L: is a unique blend of chemicals based on natural sources. It facilitates the better removal of ink along with Sebrite DI in the deinking cell or by washing deinking.
The pulp and paper industry considered one of the largest energy consuming industries of the world. It is well known that today, energy saving is the main task. Enzyme, in pulp and paper industry, can be potential for saving the electric energy in terms of revolution as well as improve the physical properties of paper. Because, hardwood pulp contains about 25% vessels cells along with 10% parenchyma and other fines. Vessels cells are large and hard to refine so that not fibrillated during normal refining process and cause the problem in bond formation with cellulose fiber. Therefore, picked out during printing Fines, which are mainly made of celluloses, blocks the pores of wire on paper machine subsequently slow down the drainage rate. SEBrite BFR breaks the glycosidic bonds of primary cell wall of fiber and expose the secondary cell wall during refining thus more fibrillation will be achieved in short time of beating. Secondly, cellulase also improves the swelling and fibrillation of vessels cell and result in decrease in vessels picking subsequently increased strength properties of paper. Beside this, cellulases digest the fines present in hardwood pulp and improve the drainage during paper making process subsequently save the energy consumption on paper machine.
Products:
SEBRITE BFR: Sebrite-BFR is an enzyme based refining additive. It makes cellulose fiber spongy and swelled. During beating/refining process, swelled primary cell wall raptures easily and expose the secondary cell wall for more fibrillation in short time of refining.
Stickies are contaminants in recovered paper excluding extractives. Waste paper contains different adhering substances, require for making of specialty papers. These are mainly, coating starch, ink binders, gums and waxes used in carton packaging. Substances classified as wood extractives may also include, in addition to actual wood resin, fatty acids from deinking aids or resin acids from rosin sizes. These gummy substances adhere on paper machine roll during paper making process. Stickies cause product quality problems, such as holes and specks in paper, which may lead to higher paper rejection or to customer reclamations. Runability problems, such as sheet breaks, occur both at the paper machine and at printing houses. It is common to have a build-up of black and sticky or gummy deposits on the drying cylinders or calendars. Doctoring the cylinders helps to some extent, but does not totally solve the problem. Down-time due to washing and cleaning is the consequence of the runability problems.
Our enzyme formulation Sebrite STR dissolves and removes selectively these stickies substances from process and improves the paper quality and formation speed.
Products:
SEBRITE STR: is an eco-friendly, biodegradable formulation prepared especially for dissolving the waxes and acidic extractive present in wood pulp.
