Wet pulping system and method for producing cellulosic insulation with low ash content

Abstract

Apparatus and method for recovering organic cellulosic fibers from landfill materials (such as post consumer, municipal and industrial waste materials). The apparatus and method selectively introduces waste materials containing organic cellulosic fibers into a size reduction machine. The pre-cleaned waste materials are conveyed to a tank, drum, or tunnel type fiber recovery apparatus. The waste materials are subjected to mechanical and fluid fiberization for a selected period of time to produce useful products, such as cellulosic insulation with a total ash content equal to or less than 10%, as well animal and fowl bedding products that is substantially devoid of moisture content, among other products.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application is a continuation-in-part of, and claims priority to, co-pending U.S. patent application Ser. No. 11 / 610,977, filed Dec. 14, 2006, and now U.S. Pat. No. 7,758,719, which application claims the benefit of U.S. Provisional Application No. 60 / 750,788, filed on Dec. 16, 2005, the specifications of each of which are incorporated herein in their entireties.BACKGROUND OF THE INVENTION[0002]1. Field of Invention[0003]The present invention relates to systems and methods for recovering cellulosic fiber from waste products such as landfill materials, e.g., post-consumer, municipal, and industrial waste materials, and to systems and methods for removing and recovering adverse inorganic chemicals and materials from such products in order to produce cellulosic thermal insulation with certain performance and ash content characteristics, as well as to produce material used in fowl and animal bedding with certain desirable characteristics...

AI Technical Summary

Benefits of technology

[0039]Still another aspect of the present invention is to recover commercially viable compounds (such as aluminum hydroxide, magnesium hydroxide, and calcium carbonate) in order to reduce the overall cost of the fiber recovery process.

[0044]According to the first aspect of the present invention, the step of drying comprises: drying the fluffed fibers at a temperature from about 150° F. to about 700° F., thereby reducing bacteria content of the recovered fibers, and drying them to a uniform moisture content, and wherein the uniform moisture content is between about 10% and about 18%. According to the first aspect of the present invention, the dried fibers have a bulk density of between about 2 pounds per cubic foot to about 6 pounds per cubic foot, and the dried fibers are used for animal and fowl bedding and have a higher degree of absorbency than sawdust, straw, wood shaving, or conventional paper-based bedding, and further wherein the dried fibers used for animal and fowl bedding are about six times more absorbent than sawdust, straw or wood shavings. Still further according to the first aspect of the present invention, the dried fibers used for animal and fowl bedding are between about 18% to about 25% more absorbent than conventional paper-based bedding, and incur between about 40% to about 50% less compaction than conventional paper-based animal and fowl bedding.

[0049]According to the third aspect of the present invention, the fiber product has a higher absorbency than wood shavings, sawdust or straw and conventional paper-based litter, and the fiber product reduces foot sores in poultry products in comparison to wood based bedding. Still further according to the third aspect of the present invention, fiber product is used for animal and fowl bedding and incurs between about 40% to about 50% less compaction than conventional paper-based animal and fowl bedding.

[0051]According to the fourth aspect of the present invention, the system still further comprises k. means for subjecting the recovered fibers to a mechanical disk refiner to control fiber length, fiber bundle separation and fiber surface properties; l. means for removing contaminants consisting of fillers, fines, coatings and other extraneous materials through the use of one or more clarifiers with select solids separation reagents and polymers; m. means for extracting pulping fluids and water from the recovered fibers to formulate a cellulosic fiber wet lap of about 40% to about 60% pulp solids content; n. means for fluffing the cellulosic fiber wet lap in a cake fluffer and a disk refiner; o. means for drying the fluffed fibers in a flash and / or tunnel dryer; and p. means for conveying the dried fibers to a packaging or baling system. According to the fourth aspect of the present invention, the means for drying comprises: drying the fluffed fibers at a temperature above about 150° F. to about 700° F., thereby reducing bacteria in the fluffed recovered fibers.

[0052]According to the fourth aspect of the present invention, the means for drying comprises: drying the fluffed fibers at a temperature above about 300° F., thereby reducing bacteria in the fluffed recovered fibers, and drying them to a uniform moisture content, and wherein the moisture content is between about 10% and about 18%.

Problems solved by technology

In recent years it has become more difficult to obtain clean waste newsprint at acceptable prices in order to manufacture cellulosic insulation using the common dry manufacturing process mentioned above (which process is currently utilized by the entire U.S. cellulosic insulation market).

In addition, the cost of clean dry waste newsprint has risen to levels that make it difficult to economically and competitively manufacture acceptable cellulosic insulation.

The most significant challenge facing conventional processes is the quality and composition of ONP.

The addition of various fillers (primarily calcium carbonate; CaCO3) has caused difficulty for cellulose insulation manufacturers to maintain good (lower) densities and a low-dust level product.

The measurement of a product's thermal performance (R-value) is hindered by high densities and high levels of inorganic particles.

Additionally, the advent of single-stream recycling programs has significantly reduced the availability of high quality ONP, one that is virtually free of contaminants and is dry.

This method has not proven to be successful commercially to produce a cellulose based fiber insulation.

Current levels of calcium carbonate and other fillers along with the increasing use of short fibers (fines) in the recycled waste paper stream is presenting a major problem for dry process cellulosic insulation manufacturers today.

The manufacture of quality cellulosic thermal insulation will become increasingly more difficult using the processes and technologies that are available today.

Despite these known approaches, and the increasing need for quality waste products, no commercial process has been developed to produce cellulosic insulation out of waste paper materials that are contaminated with a high degree of calcium carbonate, fines, and other non-organic materials (such as plastics, foils, glass, metal and other non-organic content), and materials that are contained in, commingled with, or laminated to the cellulosic fibers or waste fibers.

These waste materials are currently sent to a landfill and landfills are becoming increasingly scarce and difficult to build.

In regard to animal and fowl bedding materials, conventional paper-based bedding frequently contains contaminants that are a result of poor quality old newspapers.

Since the animals frequently ingest the bedding, some of these contaminants can cause illness and therefore growth issues with the animals.

Mold and bacteria are a significant problem with conventional wood shavings or sawdust.

These tend to not be as absorbent and compact tightly minimizing the thermal advantages.

Conventional paper-based bedding is produced in a dry process using various shredders and hammer-mills, thus making the addition of additives that adequately adhere to the fibers difficult or inefficient.

Conventional processes do not have the capability of managing and therefore reducing the inorganic components of the raw material.

Excess moisture in the litter increases the incidence of breast blisters, skin burns, scabby areas, bruising, condemnations and downgrades.

Wet litter is also the primary cause of ammonia emissions, one of the most serious performance and environmental factors affecting broiler production today.

TABLE IAdvantages and Disadvantages of VariousAnimal and Fowl Bedding MaterialsPine shavingsPreferred litter material but becoming limitedand sawdustin supply and expensive in areas.Hardwood shavingsOften high in moisture and susceptible toand sawdustdangerous mold growth if stored improperlyprior to use.Pine orUsed successfully but may cause increasedhardwood chipsincidence of breast blisters if allowed tobecome too wet.Pine orSimilar to chips or shavings in moisturehardwood barkabsorption capacity.

More difficult to maintainsuitable floor temperatures during coldweather brooding.

Moldhay or corn stovergrowth can also be a disadvantage.Processed paperVarious forms of processed paper haveproven to be good litter material in researchand commercial situations.

Despite these known animal and fowl bedding products, and the increasing need for a high quality, inexpensive and widely available product, limited commercial products or processes have been developed to meet the needs of private and commercial animal owners for animal and fowl bedding.

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