Method for improved pulping using an environmentally friendly pulping aid

Abstract

A safe and environmentally friendly pulping aid comprising a mixture of natural terpene-based chemicals and a dispersant blend. The pulping aid is used in the pulping of lignocellulosic biomass to simultaneously increase screened pulp yield and reduce the extractives content of pulp. The flash point of the pulping aid is at least 49° C.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a method of improving the digestion of lignocellulose biomass used in the production of pulp, paper and paperboard products through the addition of a novel environmentally friendly pulping aid. The present invention also relates to a method of improving the production of pulp, paper and paperboard products by the addition of a novel environmentally friendly pulping aid.BACKGROUND OF THE INVENTION[0002]The pulping of lignocellulosic materials is well known. As described by Smook (2002, pp. 67-84), there are many pulping processes available. The pulping process of highest commercial relevance is the kraft process. Briefly described, in the kraft pulping process lignocellulosic material, typically in the form of wood chips of specified dimensions, is contacted with the “cooking liquor,” which is an aqueous mixture of pulping chemicals, principally sodium hydroxide and sodium sulfide. These chemicals, in combination with tempe...

AI Technical Summary

Benefits of technology

The present invention provides an improved method for pulping lignocellulosic biomass using a safe and environmentally friendly pulping aid composed of a terpene mixture and a dispersant blend. This additive reduces the amount of pitch-generating components present in the pulp and increases the efficiency of the pulping process. It also enhances the papermachine runnability by reducing or eliminating foam without the use of defoamers added in the fiber line. The pulping aid acts on pitch-generating molecules or particles, making them more accessible to the pulping chemicals, which leads to enhanced pulping characteristics. The amount of pitch-generating components present in the pulp is reduced to improve the efficiency of the pulping process used to produce kraft, sulfite, and soda-based pulps, and dissolving pulps.

Problems solved by technology

Pulping aids are typically added directly to the pulping chemicals and thus require little-to-no additional capital investment in new pulping equipment that would otherwise limit their use.

Pitch deposits are objectionable, as they are not easily removed from the pulp.

If these pitch deposits are not removed from the pulp they will be carried over to the final pulp or paper product, which can result in costly quality-related losses.

Further, they will contaminate the surfaces on pulp and papermaking equipment, which will reduce operational efficiencies as, for example, when production must be interrupted to clean these surfaces.

Methods for enzymatic degradation of pitch and pitch precursors using lipases and other enzymes (U.S. Pat. No. 5,176,796) have been developed but are not widely practiced due to the relatively high cost of enzymes.

Foam is generally regarded as a problem in most pulp and paper operations.

For example, foam will impede the dewatering of the pulp slurry, resulting in operational inefficiencies, especially during pulp washing and papermaking.

The addition of defoamer adds cost and can result in unwanted deposits on both papermaking equipment and in the final pulp or paper product.

As discussed by Thomas (2011), the use of solvents, such as aliphatic hydrocarbons, are effective for removing organic deposits on papermachine surfaces but are currently not used because of their low flash points and their potential of generating high levels of volatile organic carbon (VOC) compounds.

Pulping aids with low flash points are not desirable because they pose environmental and safety hazards.

However, pure terpenes generally have low flash points and are thus not suitable to pulp and papermaking applications.

However, no terpene-based pulping aid has been used in the pulping processes.

Many pulping aids have been shown to be environmentally unfriendly and / or pose safety risks.

As described in U.S. Pat. No. 8,025,762, the disposal of some pulping aids is difficult, which limits their adoption.

Ethoxylated alkyl phenol degradation products have also been identified as being highly toxic to aquatic organisms, and organic solvents such as kerosene have long been discontinued due to their toxicity and flammability (Brogdon and Adiwinata, 2011).

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