Functionalized cellulose fibers for dewatering and energy efficiency improvements

Abstract

The present disclosure provides methods of improving dewatering in the papermaking process by incorporation of functionalized cellulose fibers in the paper furnish. Additionally, the disclosure provides the means to eliminate process problems mainly plugging problems in a nano / micro-fibrillated cellulose production process by incorporation of functionalized cellulose fibers in a cellulose fiber composition and methods of functionalizing cellulose fibers in a paper making process. The methods according to the present disclosure provide several advantages, such as improving the freeness and dewatering of the paper making process during the paper making process, leading to an increased production rate and reduced energy consumption.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit under 35 USC §119(e) of U.S. Provisional Application Ser. No. 61 / 783,669, filed on Mar. 14, 2013, the entire disclosure of which is incorporated herein by reference.TECHNICAL FIELD[0002]The invention relates to the functionalization of cellulose fibers by a process to render all or part of their surface to be hydrophobic. The invention includes methods for improving the dewatering and drainage practices involved in a paper making process, improving flow properties in papermaking nano / micro-fibrillated cellulose production processes resulting in improvements in energy expenditures associated with the current process and significantly reduced plugging problems during nano / micro-fibrillated cellulose production.BACKGROUND AND SUMMARY OF THE INVENTION[0003]The process of making paper requires a large amount of energy, and nearly 80% of the required energy is consumed by paper drying. In particular, the size...

AI Technical Summary

Benefits of technology

This patent text discusses the cost and environmental impact of removing water from the paper making process. The text explains that by removing as much water as possible during the first two stages of the process, the load on the steam heated dryer is reduced and papermaking economics are improved. The text also mentions that improving water drainage even slightly can have a significant impact on both financial and environmental performance. Additionally, the patent text suggests that improving freeness in the paper making process or nano / micro-fibrillated cellulose production process can lead to improved efficiency and performance.

Problems solved by technology

The process of making paper requires a large amount of energy, and nearly 80% of the required energy is consumed by paper drying.

In particular, the sizeable proportion of energy necessary for paper drying is due to the process of drying by vaporization.

The ease with which water is released from furnish during the papermaking process affects both the production rate and energy consumption.

The entire dewatering process for sheet formation is a very complex sequence utilizing various physical phenomena.

All of these process steps require a substantial amount of energy and demand very high capital equipment investments and maintenance costs.

Although several R / D additives have been investigated for their effects on the water removal on the forming process, doing so often causes one or more disadvantages at a subsequent step in the paper making process.

Although positive effects of various R / D additives on water drainage gravity-filtration of fiber suspensions have been suggested, parallel tests carried out with application of vacuum gave contradictory results.

However, excessive treatment of fibers with enzymes have been found to increase the fines content of furnish, thus reducing the dewatering ability.

However, similar tests with application of vacuum have been reported to give different results.

In addition, using CATPAM can improve dewatering in the wire, but lesser water removal at the press section due to the formation of persistent fiber flocs by the chemical treatments.

Once most of the water has been removed by the application vacuum, the same void spaces allow air to rush ineffectively through the wet web, failing to maintain a pressure differential across the thickness of the sheet.

In addition, sheets with highly flocculated fibers were found to require longer application heat in the drying section to remove the remaining water in the sheet by evaporation.

Second, the methods improve the suspension flow of the cellulosic fiber composition during the paper making process, leading to a lower amount of cellulosic fiber flocculation during the process.

Third, the methods improve the bulk of the resultant paper made during the process.

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