Pyrolysis of spent pulping liquors

Claim 1

A method as in claim 1 wherein said heating is effected at a temperature of from 550*F. to 650*F. and under a pressure of from 1,300 to about 2,700 lbs./sq. inch for a period of from about 20 minutes to 1 hour.

Claim 6

A method for the separation of organic chemical values present in an aqueous spent liquor solution resulting from reaction in aqueous medium at elevated temperature of a lignocellulosic material with a sodium and sulphur containing pulping agent and removal of the pulp, which comprises: heating the aqueous spent liquor solution in the absence of additive reagents at a temperature of from about 490*F. to about 700*F. and under a pressure of from about 1,000 to about 3,500 lbs./sq. inch for a period of from about 10 minutes to 3 hours to evolve a first portion of said organic chemical values as a vapor containing organic chemical compounds and sulphides and to precipitate a second portion of said values from the remaining aqueous solution containing sodium compoundS, separating said precipitate from said solution for separately recovering said precipitate and sodium values, cooling said vapor to condense and separate organic values therein, and recovering sulphur values from the uncondensed vapor as hydrogen sulphide.

Claim 7

A method for the separation of organic chemical values present in an aqueous spent liquor solution resulting from reaction in aqueous medium at elevated temperature of a lignocellulosic material with a pulping agent containing sodium and sulphur compounds, which comprises: heating the aqueous spent liquor solution in the absence of additive reagents at a temperature of from about 490*F. to about 700*F. and under a pressure of from about 1,000 to about 3,500 lbs./sq. inch for a period of from about 10 minutes to 3 hours to evolve a first portion of said organic chemical values as a vapor containing organic chemical compounds and sulphides and to precipitate a second portion of said values from the remaining aqueous solution containing sodium compounds, separating said precipitate from said solution, cooling said vapor to condense organic values, and recovering sulphur values from the uncondensed vapor as hydrogen sulphide.

Claim 8

A method for the separation of organic chemical values present in an aqueous spent liquor solution resulting from reaction in aqueous medium at elevated temperature of a lignocellulosic material with a sodium and sulphur containing pulping agent and removal of the pulp, which comprises: heating the aqueous spent liquor solution in the absence of additive reagents at a temperature of from about 490*F. to about 700*F. and under a pressure of from about 1,000 to about 3,500 lbs./sq. inch for a period of from about 10 minutes to 3 hours to evolve a first portion of said organic chemical values as a vapor containing organic chemical compounds and sulphides and to precipitate a second portion of said values from the remaining aqueous solution containing sodium compounds, separating said precipitate and lime causticizing said solution for converting sodium values to NaOH, cooling said vapor to condense and separate organic values, recovering sulphur values from the uncondensed vapor as H2S, and contacting said causticized solution therewith to produce Na2S therein.

Claim 9

A method for the separation of organic chemical values present in an aqueous spent liquor solution resulting from reaction in aqueous medium at elevated temperature of a lignocellulosic material with an NaOH and H2S containing pulping agent and removal of the pulp, which comprises: heating the aqueous spent liquor solution in the absence of additive reagents at a temperature of from about 490*F. to about 700*F. and under a pressure of from about 1,000 to about 3,500 lbs./sq. inch for a period of from about 10 minutes to 3 hours to evolve a first portion of said organic chemical values as a vapor containing organic chemical compounds and sulphides and to precipitate a second portion of said values from the remaining aqueous solution containing sodium compound, lime causticizing said solution for converting sodium values to NaOH, cooling said vapor to condense organic values, recovering sulphur values from the uncondensed vapor as H2S and contacting said causticized solution therewith to produce Na2S therein, and recycling said solution to said pulping stage.

Claim 10

A method for the separation of organic chemical values present in an aqueous spent liquor solution resulting from reaction in aqueous medium at elevated temperature of a lignocellulosic material with a pulping agent and removal of the pulp, which comprises: heating the aqueous spent liquor solution in the absence of additive reagents, at a temperature of from about 490*F. to about 700*F. and under a pressure of from about 1,000 to about 3,500 LBS./SQ. inch for a period of from about 10 minutes to 3 hours whereby a first portion of said organic chemical values is evolved as a vapor from said solution, and a second portion separates as a solid precipitate from the remaining aqueous solution, wherein the lignocellulosic material is wood and said pulping agent reacts with said lignocellulosic material to form tall oil soap containing fatty and resin acids, and wherein the spent liquor is concentrated by evaporation prior to said heating under said pressure, to a total solids content of from about 23 to about 27 percent, by weight, based on the total weight, thereby to cause the separation from said liquor of the tall oil soap content thereof, and the tall oil soap is removed prior to said heating under said pressure.

Claim 11

A method for the separation of organic chemical values present in an aqueous spent liquor solution resulting from reaction in aqueous medium at elevated temperature of a lignocellulosic material with a pulping agent and removal of the pulp, which comprises: heating the aqueous spent liquor solution in the absence of additive reagents, at a temperature of from about 490*F. to about 700*F. and under a pressure of from about 1,000 to about 3,500 lbs./sq. inch for a period of from about 10 minutes to 3 hours whereby a first portion of said organic chemical values is evolved as a vapor from said solution, and a second portion separates as a solid precipitate from the remaining aqueous solution, cooling the evolved vapor to form a condensed fraction comprising hydroxylated, monocyclic and other aromatic compounds, and an uncondensed fraction comprising fractions consisting principally of methyl mercaptan, dimethyl sulfide, H2S, CO2 and hydrocarbons.