US1626171A

US1626171A - Process for cooking vegetable fiber

Info

Publication number: US1626171A
Application number: US119471A
Authority: US
Inventors: Sidney D Wells
Original assignee: Individual
Current assignee: Individual
Priority date: 1926-06-29
Filing date: 1926-06-29
Publication date: 1927-04-26
Anticipated expiration: 1944-04-26
Also published as: NL23102C; FR633801A; GB273663A; DE490384C

Description

Patented Apr. 26, 1927.

UNITED STATES SIDNEY D. WELLS, OF QUINCY,

PROCESS FOR COOKING VEGETABLE FIBER.

No Drawing.

This invention relates to processes for softening vegetable fibrous material, such as wood, cereal straws, and grasses, whereby a ren'iarkably fine product may be obtained by the use of relatively inexpensive chemicals.

The process includes the use of sodium carbonate and sulphur and is conducted under such conditions that these materials combine and effect desired changes in the fibrous ma terial such-as heretofore have been obtainable only by the use of more expensiv chemicals. The resultant paper or paper board produced from materials obtained by this process is more pliable and stronger than that ordinarily obtainable from straw, for example, by other methods such as give yields above fifty or sixty per cent. Under the microscope, the fibers give the color reactions characteristic of well cooked pulp obtainable by the sulphate process and which is c011- sidercd a much finer product than the usual straw pulps such as are obtained in cooking straw with lime. The cheapness of the cooking reagents proposed as result of this present invention and the quality of the product makes possible the more complete utilization of straw.

In conducting the process, the cooking vessels, digestors, are charged with straw or other vegetable fibrous material in the usual I manner together with about seven pounds sodium carbonate, one pound of sulphur, and twenty-five gallons of water for each one hundred pounds dry weight of straw. A

cooking treatment of six hours is suflicient if at least five and one-half hours are at a temperature of 145 C. The action is conducted in closed vessels, and of course at itl pressures greater than atmospheric pressure.

After digestion, the stock is dumped,

washed, and beaten in accordance with any ofthe methods practiced in the art and such subsequent steps form no part of the present inventlon.

Sulphur will not combine with sodium carbonate at the temperature of 100. C. or below, but in practicing the present invention, it has been found that if these materials are heated to temperatures of approximately 120 ,C. or above in the presence of water and vegetable fibrous material, the cooking effect approximates that obtained when sodium sulphide or h drosulphide is used,

and a softened material is obtained which may be converted to paper or paper board Application filed June 29,

1926. Serial No. 119,471.

products using the usual methods. Under the conditions of the cookin sodium is weakly ionized to Na and HC 3 ions. The Na ions probably act in conjunction with OH ions from the water on the sulphur and the same ions are formed that occur when sodium sulphide is dissolved in water.

The chemicals may be combined in rotary digestors in the presence of straw and water or by suitable mechanical means before being introduced into the digestors.

Heretofore, it has been proposed to use sulphur with soda ash and under conditions in which the sulphur is used as a colloidal material as an important feature and under temperature conditions at which there is no chemical combination between the sulphur and the soda ash. The present process in contrast to such prior uses depends on the softening action produced when these materials combine as effected by heating in the presence of vegetable fibrous material. It is believed to be new to use sulphur compounds in the manner described and claimed.

Sulphur has also previously been used in combination with caustic soda and also in combination with lime. The result of the first would be the formation of caustic soda and sodium sulphide, simulating a modification of the soda process and not relying on the use of sodium carbonate as the softening agent, as in the present invention. vVhere lime has been used with sulphur, theproducts formed are different from those of the present process, and in one use, it has been necessary to supplement such materials with sodium carbonate used, not as a cooking agent, but as an eliminator for undesirable products formed in the digestion when lime and sulphur are present.-

Claims to the use of sodium carbonate and sulphur compounds and emphasizing the avoiding of causticizing are embodied in my pending application, Serial No. 137,819, filed- September 25, 1926. V

I claim 1. In a process of softening ve etable fibrous material, the steps consisting o treatwith a solution of sodium carbonate and sulphur, and under temperature conditions of at least 120 C. I

4:. In a process of softening vegetable fibrous material, the steps consisting of treating such fibrous material with a solution of sodium carbonate and sulphur in proportions of approximately seven parts of the carbonate to one art of sulphur for each one hundred parts 0 fibrous material.

5. In a process of softening vegetable fibrous material, the steps consisting of treating such fibrous material with a solution of sodium carbonate and sulphur in proportions of approximately seven parts of carbonate to one part of sulphur and with two hundred parts of water for each one hundred parts of vegetable fibrous material.

'6. In a process of softening vegetable fibrous material, the steps consisting of treating such fibrous material in a closed vessel with a solution of sodium carbonate and sulphur in proportions of approximately seven parts of carbonate to one part of sulphur and with two hundred parts of water for each one hundred parts of vegetable fibrous material and under temperature conditions of approximately 145 C. maintained for a period of at least five and one-half hours.

7. In a process of softening vegetable fibrous material, the steps consisting of treating such fibrous material in a closed vessel and under pressure greater than atmospheric ressure and with a solution of sodium caronate and sulphur and under temperature conditions of approximately 145 C. main: tained for at least five and one-half hours.

8. In a process of softening vegetable fibrous material, the steps consisting of mixing a water solution solelyof sodium carbonate and'sulphur and cooking vegetable fibrous material with such a resultant mixture and thereby softening the fibrous material.

In testimony whereof I affix my signature.

SIDNEY D. WELLS.