Repap Technologies Inc.

Alcell Technologies Inc.

Other

Jairo H Lora

Joseph R Phillips

Brian F Greenwood

Raphael Katzen

Malcolm Cronlund

David J Lebel

John Patrick Maley

William H Klingensmith

Stephen R Winner

Ron LeBlanc

Gopal C Goyal

Mikhail N Raskin

Chih Fae Wu

Michael J Trojan

Richard C Agar

Chih F Wu

A continuous solvent pulping process is practiced with oxygen free gas (e.g. nitrogen) purges of all major treatment vessels during the time when the process is arrested or terminated. The wood chips or other cellulosic fibrous material to be pulped is steamed in a first horizontal steaming zone at pressure of about 10-20 psi, and then in a second horizontal steaming zone at a pressure of about 20-75 psi. The first and second zones are isolated by a low pressure feeder. Steam is introduced into the material in the second steaming zone to flow cocurrently with it. Gases, including vaporized solvent (e.g. ethanol or other alcohol) are vented from the steaming zones, and solvent is added to the steamed material prior to feeding to a high pressure feeder. The high pressure feeder introduces the material into the top of a single digesting vessel, liquid and chips being separated at the top of the digester vessel without mechanical means that could cause a spark. Lignin containing liquid is withdrawn from a central portion of the digester and passed through flash tanks and ultimately for lignin and alcohol recovery. A recirculating screen and system is disposed between the central extraction portion and the top of the digester vessel. A portion of the liquid removed for recirculation is instead passed to lignin recovery, while fresh solvent containing liquid is added to the rest of the recirculated liquid.

Method for steaming comminuted cellulosic fibrous material during

This invention provides for the recovery of lignin and other by-products from the pulping of fibrous plant material. In accordance with this invention, solvents and filtrates are recovered and recycled for reuse. This results in significant solvent and energy savings. Filtrates from the bleaching and delignification of the pulp are recycled for reuse in pulping, separation, and recovery of lignin and other by-products which results in significant energy savings and mitigation if not the elimination of pollution typically associated with bleaching. This invention also relates to products derived from the process and apparatus for carrying out the process. Lignins of various molecular weights and by-products of the pulping process are also recovered. The lignins are precipitated in high yields and at a high rate from a black liquor produced by pulping wood at high temperature and pressures. As a by-product of this process a purified furfural product is recovered. This furfural may be recycled for use in the recovery of the low molecular weight lignin of this process.

Method of recovering furfural from organic pulping liquor

An apparatus and process for the solvent pulping and washing of pulp using vessels purged of oxygen free gas when the process is arrested or terminated. The washing is accomplished by first continuously passing the pulp to a pressure diffuser, then to a first multi-stage drum displacer washer, and then to a second multi-stage drum displacer. In the pressure diffuser the lignin is washed out of the pulp, utilizing as wash liquid a mixture of solvent and water having a solvent concentration equal to or higher than that required by the extraction process within the digester, and at a pressure at least about 350 psi. The pressure in the second and third stages is lower, and water is the wash liquid in the third stage. Alcohol can be recovered from the spent wash liquid of the first wash stage, so that all but about ten gallons or less of alcohol per ton of pulp is recovered.

Apparatus for treating pulp produced by solvent pulping

A tackifier composition for use in rubber compounds is disclosed. The tackifier comprises a pure lignin with a water solubility of up to 1% by weight and a carbohydrate level of less than 50% by weight. In another embodiment of the invention, the pure lignin functions as both a tackifier and an antioxidant. In yet another preferred embodiment of the invention, the improved tackifier produces synergistic results when blended with a commercial tackifier, and the antioxidant likewise yields synergistic results when mixed with a commercial antioxidant.

Rubber compositions containing high purity lignin derivatives

Lignin is precipitated in high yields and at high rates from a black liquor produced by pulping wood at high temperatures and pressures with an aqueous lower aliphatic alcohol solvent. The lignin is precipitated by diluting the black liquor with water and an acid to form a solution with a pH of less than about 3, an alcohol content of less than about 30% by volume and a temperature of less than about 75.degree. C. The precipitated lignin, when subsequently dried, is in the form of a powder which requires little or no crushing to convert it into a fine uniform size suitable for use without further significant processing.

Recovery of lignin

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Media, PA, United States of America

Jairo H Lora