US2502484A

US2502484A - Process for removing solvent from solvent-wetted vegetable residues

Info

Publication number: US2502484A
Application number: US773481A
Authority: US
Inventors: Harold F Saunders
Original assignee: Sherwin Williams Co
Current assignee: Sherwin Williams Co
Priority date: 1947-09-11
Filing date: 1947-09-11
Publication date: 1950-04-04
Anticipated expiration: 1967-04-04

Description

April 4, 1950 H. F. SAUNDERS 2,502,434

PROCESS FOR REMOVING SOLVENT FROM SOLVENT-WETTED VEGETABLE RESIDUES Filed Sept. 11, 1947 2 Sheets-Sheet l MIXTURE AGITA TED sows/4r SOLVENT REMOVAL BY HEAT & PARTIAL VACUUM SEPARATION OF SOL/D5 PRECIPITATING FROM AQUEOUS LIQUID AGENT W/IjH/IVG PRECIPITATION OF 0F SOLIDS SOLUBILIZED MATERIAL IN LIQUID SOLIDS PRODUCT SEPARATION 0F,$OLID$ "a" FROM AQUEOUS LIQUID WASHING OF LIQUID SOLIDS PRODUCT SOLIDS PR ODUCT INVENTOR Harold E Saunders ATTORN EYS April 4, 1950 H. F. SAUNDERS, 2,502,484 I PROCESS FOR REMOVING SOLVENT FROM SOLVENT-WETTED VEGETABLE RESIDUES Filed Sept. 11, 1947 2 Sheets-Sheet 2 VEGETABLE RES/DUES- WETTED WITH ORGANIC SOLVENT AQUEOUS LIQUID SOLVENT MIXTURE AGITATED SOLVENT REMOVHL BY HEAT & PARTIAL VACUUM PREfIEI/Ty'giT/NG i PRECIPITATION 0F sows/1.1250 MATERIAL IN uqum SEPARATION OF .SCMJDS FROM AQUEOUS LIQUID Harold E Saunders ATTORN EYS more volatile than water.

Patented Apr. 4, 1950 PROCESS "FOR REMOVING SOLVENT FROM SOLV-ENT-WETTED VEGETABLE RESIDUES Harold F. Saunders, Shaker Heights, Ohio, as-

signor to The Sherwin-Williams 00., Cleveland, Ohio, a corporation of Ohio Application september 11, 1947, Serial No. 773,481

' 1 This invention relates to improved processes for removing sol-vent from solvent-Wetted vegee table residues, such as those remaining after solvent extraction of oils and fatty materials from oil-containing vegetable materials, and to prod ucts, containing ,proteinaceous materials, pros duced from such solvent-wetted. residues.

Such oil-containing vegetable materials are seeds, beans, nuts and leaves containing proteinaceous material and a substantial proportion of oil. Examples are cottonseed, castor beans, soya beans, peanuts, flaxseed, hempseed, sunflower seed, oiticia nut, tungnut, coconut, and the like.

Processes are widely used ,for extracting oils and fatty materials from such vegetable materials by means of organic solvents-which are'usual'ly After the vegetable material has been treated with asolvent for the extraction of oil, there remains a solvent-wetted residue which is substantially insoluble in the solvent employed. ,Such residues usually contain cellular material, proteins, carbohydrates such as sugars, mucilages, and a small proportion of water, in a more or less finely divided state. The particle size may range from colloidal dimensionsto a quarter inch or more. If the cortex or shell was not removed prior to solventtreating,

this material will also be contained in the residue. Thesolvent-wetted residues may be in the form of a cake or a solvent-slurry.

Recovery of the solvent from such residues is highlydesirable both for economic reasonsand to render the residues or proteinaceous -materials derived therefrom more useful. The reeovered solvent usually is re-employed in the solvent extraction process. Heretofore, recovery of solvent from the residues has been customarily efifected by directly heating the solvent-wetted residues to volatilize the solvent, which is subsequently con densed for reuse. Although the solvents usually employed have boiling points below 100 C., it is nevertheless generally necessary to use temperatures of about 120 :C. or more'to achieve rapid and completeremoval of thesolvent from the residues. The use of these high temperatures often results in charring or degradation of the residues and deleterious efiects upon the proteinaceous materials in the residues, particularly when water is present. .Such deleterious eifects .on the proteinaceous materials make it very diiiicult or impossible to disperse the final products in acidic, salt or alkaline solutions, as is often. desirable when using these products. Because the odor and/or toxicity of the solvent would renderresidues unfit for stock food, ithas been usually 14 Claims. (Cl. 260-1235) necessary to expose the residues to high temperatures for prolonged periods to eiiect complete removal of the solvent. This increases the possibility of charring or degradation of the residues and harmful effects on the proteinaceous materials.

When the products are to be used in paints, coating materials, adhesives and the like, it is often desirable to mix them with aqueous liquids to form'dispersions or emulsions. The practices heretofore employed in changing the solventwetted residues to water-wetted products have involved first heating the residues to substantially complete dryness to remove all of the solvent, and subsequently mixing the dried residues with an aqueous liquid. Drying the residues substantially reduces their dispersibility or solubility in water, particularly when the drying is carried out in the presence of water. This prior manner of converting a solvent-wetted material to a water-Wetted material is thus not only diflicult and expensive, but also results in poorer dispersion characteristics of the water-wetted material.

It is an object of the present invention to provide processes for removing residual solvent from solvent extracted vegetable materials, which eliminate the above-mentioned disadvantages.

It is another object of this invention to remove solvent from such solvent-wetted residues without using high temperatures or prolonged heating periods as is required by direct heating; thus eliminating the deleterious efiects of overheatmg.

'Itis a further object of this-invention to transform the solvent-wetted residues or the proteinaceous' materials derived therefrom to a water- Wetted product without drying the material so that the dispersibility or solubility is not impaired.

Another object of the invention is to provide novel products containing proteinaceous materials, including concentrated proteinaceous material substantially free of cellular material and cortex, which products are extremely de.- sirable for many purposes.

According -tothe present invention, solventwetted vegetable residues are heated, while in admixture with an aqueous liquid, to a temperature sufficientto vaporize the solvent. The aqueous liquid is such that it. dissolves or disperses a substantial proportion of the proteinaceous material in the residues. The aqueous liquid may be water, :an aqueous solutionlof a neutral salt, an aoueous acidicsolutionorpreferablyan aqueous alkaline solution which is better capable 3 of dispersing the proteinaceous materials. Advantageously, the mixture of residue, solvent and aqueous liquid is subjected to a partial vacuum to assist vaporization of the solvent from the mixture while it is being heated to a temperature below that which will adversely affect the residues or the proteinaceous materials in the residues. Preferably, the mixture is subjected to heat and partial vacuum until substantially all of the solvent has been removed from the mixture. The resulting mixture of aqueous liquid and residues which is substantially free of solvent may be used as such, or after removal of some or all of the aqueous liquid. However, the mixture may be treated further to precipitate certain proteinaceous or other materials, either in the presence of residue solids which are insoluble in the aqueous liquid, or after removal of such solids. Such a solid product may be separated from the aqueous liquid and used wet, or it may be washed, dried and pulverized before use. The separated liquid may be further pro-- cessed, if desired, to recover other useful substances therefrom. The products of the present invention may be employed as emulsifying or emulsion stabilizing agents in paints, coating materials, and adhesives, and as foods and fertilizers, and for many other purposes.

Processes according to the present invention make possible the rapid, efficient and economical removal and recovery of the solvent from the solvent-wetted residues, and the production at low cost, of high useful products from the residues.

The use of an aqueous liquid in admixture with the solvent-wetted residues provides several important advantages. For example, the aqueous liquid facilitates dispersion of the residues and, hence, facilitates vaporization of the solvent from the residues at relatively low temperatures so as to avoid harmful effects on the residues or proteinaceous materials therein. The aqueous liquid also solubilizes proteinaceous materials and facilitates their extraction from the residues.

The above advantages are obtained when the aqueous liquid is water, or a neutral salt solution or an acidic solution, but greater advantages are provided when an aqueous alkaline liquid is used because of the particularly good dispersing effect on the proteinaceous materials. Also an aqueous alkaline liquid is advantageous since it pronouncedly inhibits coagulation of heat-coagulable proteinaceous materials during solvent removal.

According to the present invention, the solvent is removed from solvent-wetted residues, and the residues are converted to a state in which they are wet with an aqueous liquid without ever passing through a dry state which could impair their dispersibility or solubility. The products of this invention have improved solubility and dispers on characteristics so they may be used, for example, in emulsions, paints, coating materials or binding materials, as fillers for plastics or other materials, as foods and as fertilizers, etc.

These and other objects, features and advantages of the invention will be apparent from the following more detailed description of the invention and the accompanying drawings.

In the drawings,

Fig. 1 represents a flow sheet illustrating one process embodying the invention; andv 4 Fig. 2 represents a flow sheet illustrating another process embodying the invention.

NATURE OF SOLVENT-WETTED RESIDUES While the present invention is applicable to the treatment of solvent-wetted vegetable residues of various kinds, it is particularly useful in the treatment of the residues remaining after seeds, beans, nuts, leaves, or other vegetable materials containing substantial amounts of oil and proteinaceous material have been crushed and treated with a solvent for removing oils and fatty materials therefrom, with or without a preliminary mechanical pressing process to express oil. Examples of such vegetable materials are cottonseed, castor beans, soya beans, peanuts, rapeseed, flaxseed, hempseed, sunflower seed, oiticia nut, tungnut, and others.

Because of the crushing, grinding or pressing operations to which the oil-containing vegetable materials are subjected before or while being subjected to solvent extraction, and because of the disintegration of structure which usually occurs during the solvent extraction, the insoluble residues remaining after solvent extraction consist of more or less finely divided solids. Such solids are wetted with the solvent, which usually has some oil and/or fatty material dissolved therein and usually contains a small amount of water originating from the vegetable materials or the solvent. Such solids may be in the form of a solvent-slurry, or a wet cake. The solids comprise cellular material, cortex, unless the seeds or beans were decorticated, proteinaceous material, carbohydrates such as sugars, and mucilages. The solids range in size from large particles which may be a quarter of an inch or larger in their largest dimensions and which usually are cortex particles, to fines dispersed in colloidal suspension.

The solvents with which the residues are wetted are organic liquids or mixtures thereof having boiling points under standard conditions of from about 35 C. to about C. When in admixture with water and when under a partial vacuum, the solvents will vaporize at temperatures below about 60 C. whereas the water will not vaporize under the same conditions. Solvents which are generally suitable for the extraction of oil from vegetable materials can be removed from the residues in this fashion. Such solvents include various oil-miscible organic solvents having boiling points below about 100 C. For example, aliphatic hydrocarbons such as hexane, heptane, and the like, their isomers, chlorinated derivatives thereof as well as various aromatic solvents such as benzene and the like have been used for oil extraction.

Solvent-wetted residues of the kind described above, whether in the form of a slurry or cake, may be referred to hereinafter as solvent-wetted pomaces.

FORMATION OF MIXTURE OF AQUEOUS LIQUID RESIDUES In the present process the solvent-wetted pomaces or residues are first mixed with an aqueous liquid. This aqueous liquidmay. be water, a solution of an alkaline substance, a solution of a neutral salt or a solution of an acid substance depending upon the desired pH of the final mixture. For reasons noted hereinafter it is generally preferred to render the mixture alkaline, although a neutral or acidic mixture may be prepared with advantage.

' The mixture of solvent-wetted residues and an aqueous liquid is prepared by mixing the solvent-wetted residues with water and then adding the alkaline or acidicsubstance or neutral salt or by mixin the solvent-wetted residues with water while adding a concentrated aqueous solution of the substance for controlling the pH. The last procedure is preferred because it is more convenient and the pH may be controlled more easily;

According to the preferred procedure, water and a concentrated solution of an alkaline material are added slowly to a solvent-wetted residue while it is subjected to rapid stirring to prevent lumping. This is particularly important when the residue contains substantial amounts of mucilages. A mixing tank having rotatable shearing blades or paddles may be used. Suflicient water is added to form a slurry which may be homogenized by circulating it from the tank, through a mixing pump, and back to the tank. A screen may be. employed in the conduit discharging into the tank, to remove from the slurry agglomerates which may be added to the next batch for reworking.

The total quantity of water added is sufficient to make an easily flowahle slurry and depends upon the nature of' the solvent-wetted residues, the amount and kind of solvent present in the residues, the nature of the products to be made from the residues and the desired pH of the mixture. Generally; it. is advantageous to use from about parts to about 50 parts by weight of" water to one part of solid residues. The lower pro ortions of water can be employed when the residues have a low mucilagenous content as in the case of soya bean, castor bean, peanut or cottonseed or when it. is desired to solubilize and extract from the residues a minimum quantity of proteinaceous material. The higher proportions of water are employed when the residues have a high content of mucilage as with flaxseed' or when it is desired to solubilize and extract a maximum amount of proteinaceous material.

The pH value of the resulting mixture of aqueous liquid and. solvent-wetted residues is important in controlling the nature of the products to be obtained. According to the invention, the mixture may have av pH value lying within the range of fromabout 5 to about 13', although beneficial results are obtained even when the mixture has anH value above or below this range. Whenthe mixture has a pH value of from about 5 to about 8, the aqueous liquid disperses the residues.

and opens up the structure of the solids more efficiently, thus making possible the use of low temperatures for removing the solvent, and the production of water-wetted products without an intermediate drying operation.

However, when the mixture has a pH value of from about 8 to about 13', considerably increased.

advantages are obtained. A pH value in this range greatly aids in dispersing the residues; in inhibiting lumping andv agglomeration of the residues, both during and after removal of the solvent; in'opening up the structure of the solids in the residues; in solubilizing proteinaceous materials in the residues; in inhibiting coagulation of heat-coagulable proteinaceous materials during solvent removal; in facilitating release of solvent from the residues, thus permitting the use of lower temperatures for solvent removal; and" in facilitating. release of proteinaceous materials from the residues. For optimum effects 6- along these lines a pH value of from about 10 to about 12 is most advantageous.

The lower pH values may be obtained when the solvent-wetted residues are mixed with water alone, or with an aqueous solution of a suitable, preferably neutral, salt, such as NaCl, NH4C1, K01, Na2SO4, or with an aqueous acidic solution. When a salt solution is used, the salt is preferably in a concentration of about 5% to about 10%, by weight. If an aqueous acidic solution. is used to obtain amixture havingv low pH, either an acid or a compond giving an acidic reaction can be used, such as sulfuric acid, hydrochloric acid, sulfurous acid, acetic acid, S02 gas, or salts'which produce acidic solutions.

However, when an alkaline solution is desired, a water-soluble alkaline compound or a watersoluble compound capable of producing alkaline reactions, such as sodium hydroxide, potassium hydroxide, ammonium hydroxide, sodium carbonate, potassium carbonate, sodium sulfite, potassiurn sulfite, and ammonium sulfite is dissolved in the water. These compounds are readily soluble and, if the mixture is acidified in a subsequent step of the process, as described hereinafter, a soluble salt is formed, thus avoiding undesirable precipitates.

Some of the alkaline components tend to react with constituents of the residues over a period of time, thus resulting in a lowering of the alkalinity of the aqueous liquid in contact with the residues. Hence, it may be advisable or necessary to add more alkaline material to the mixture, either continuously or from time to time, to maintain the pH at approximately the value necessary to prevent precipitation of desired solu'- bilized materials.

In the mixture prepared as indicated above, the solid residues are preferentially wetted by the solvent, and they tend to float with the solvent on the aqueous liquid. In this state, the mixture is filterable only with the greatest difficu ty and separation of the liquids from the solids by centrifuging is most ineflicient, since the solids flow off with the liquid. As the solvent is re'-.

moved by evaporation, the solids in the mixture become preferentially wetted by the aqueous.

liquid". This change is observed when the solids begin to settle in the aqueous liquid, after which they can be readily separated by filtration or centrifuging.

It is not necessary to remove all of the solvent to change the wetting characteristics of the solids, but for reasons of economy and for removal of solvent odors from the final product, it is preferred to remove substantially all of the solvent.

REMOVAL OF SOLVENT the solvent, thus permitting the use of low heating temperatures. Agitation of the mixture inhibits settling of the residues and aids in flushing the solvent out from the mixture. As was indicated above, low heating temperatures are desirable because they cause little, if any, degradation of the residues or the proteinaceous materials. Solvents of the kind defined. above, may be rapidly and substantially completely removed from the mixture by heating to atemperature not higher than about C. while under a partial vacuum. When solvents having lower boiling points are present in the mixture, temperatures within the range from about C. to about C., at a pressure of about 28 inches of mercury, are sufficient for substantially complete removal of the solvent.

The removal of the solvent is greatly facilitated if the mixture is in the form of a film, spray or stream, so that a large surface is exposed to the vaporization condition.

Any type of apparatus or vessel may be used for evaporating the solvent though it is desirable to provide means for introducing the mixture into the vessel, as a spray or stream, a substantial distance above the normal liquid level in the vessel. In this case at least a portion of the liquid in the bottom of the vessel may be recirculated to the point of initial introduction for more eflicient and complete removal of the solvent. The vessel may be heated directly by injecting steam thereinto or indirectly by a heating medium circulated through heating coils or the like. The solvent vapors are withdrawn from the vessel and condensed for reuse in the solvent extraction of the vegetable materials.

The mixture is agitated, during removal of the solvent, by the splashing of the fresh or recirculated mixture onto the liquid in the bottom of the vessel, by the recirculation, or by paddles or the like provided in the vessel for that purpose. The heating and recirculation of the mixture are continued until substantially all the solvent is removed from the mixture. This may be readily determined by examining a sample of the mixture to determine Whether the solids settle in the aqueous liquid and whether the odor of the solvent persists.

After removal of the solvent, the mixture comprises an aqueous liquid, finely divided solids therein, and other materials colloidally dispersed and/or dissolved therein. The solids include cellular material, cortex if not initially removed, proteinaceous materials which are insoluble in the aqueous liquid and other insoluble materials. The colloidally dispersed and/or dissolved materials include solubilized prote naceous materials, sugars, mucilages, and other materials wholly or partially soluble in the liquid. This mixture may be used as such, or after removal of the aqueous liquid followed by washing and/or drying, for various purposes such as in compositions for binding, filling or coating. However, the mixture is preferably further treated to produce more desirable products.

FURTHER TREATMENT OF DESOLVENTIZED MIXTURES The desolventized mixture may be treated with a reagent which will precipitate solubilized proteinaceous and other materials in the mixture, either in the presence of the solids in the mixture or after the solids in the mixture have been removed from the aqueous liquid by filtration, centrifuging or otherwise. In either case, precipitation may be effected by adjusting the pH value of the mixture to that at which the maximum precipitation of the solubilized or dispersed proteinaceous material in the liquid will occur. This pH value varies with the nature of the residues being treated but, in general, is from about 3 to about 6. Thus, the pH value at which maximum precipitation of proteinaceous material occurs from a mixture derived from linseed is about 3.5; from castor residues the pH value is from about 3.8 to about 4.0, and from peanut or cottonseed residues it is from about.4.0 to about 4.5.

After the precipitation of proteinaceous and other materials, the resulting mixture of solids in the aqueous liquid may be used as such or after partial or complete removal of the aqueous liquid. Preferably, the solids are separated from the aqueous liquid as by filtering or centrifuging, and washed. The resulting solids, while wet or after drying, may be comminuted by pulverizing or grinding before use.

The liquid separated from the solids contains unprecipitated proteinaceous and other materials. It may be discarded or processed further for recovery of useful products.

In general, greater amounts of proteinaceous materials can be precipitated if the mixture, before the desolventizing step, has an alkaline pH of from about 8 to about 13 and preferably from about 10 to about 12. This causes greater solubilization and colloidal dispersion of proteinaceous materials than is generally possible at other pH values. The precipitation is carried out by acidifying the desolventized mixture to a pH value at which the maximum precipitation of the solubilized and/or dispersed proteinaceous materials in the liquid occurs.

Of course, if the mixture prior to the precipitation step has a pH value lower than about 8 but above the pH value at which maximum precipitation of the solubilized and/ or dispersed proteinaceous materials occurs, precipitation can nevertheless be effected by acidifying the mixture to the pH value affording maximum precipitation.

On the other hand, if the mixture, before the precipitation treatment, has a pH value lower than that at which the maximum precipitation of solubilized and/or dispersed proteinaceous materials occurs, increased precipitation may be effected by treatment with a suitable alkaline material, such as those mentioned above, to raise the pH value to that at which maximum precipitationof proteinaceous materials from the mixture will occur.

The acidic material which may be employed to precipitate proteinaceous and other materials may be an acid or a compound capable of producing an acidic solution of the desired pH value. For best results, the acidic material shouldnot form insoluble precipitates with the alkaline compound present in the mixture. Examples of suitable acidic compounds are sulfuric acid, hydrochloric acid, sulfurous acid, acetic acid, S02 gas, and salts which produce acidic solutions.

FLOW DIAGRAMS Fig. '1 is a flow diagram illustrating one process according to the present invention. In this process the solvent-wetted residues are mixed with an aqueous liquid, preferably an alkaline solution, to form the mixture of solvent wetted residues and an aqueous liquid of the desired pH value. This mixture is then heated under vacuum while being agitated, to remove most and preferably all of the solvent therefrom. The resulting desolventized mixture containing solids wetted with the aqueous liquid and colloidally dispersed and/or dissolved materials, is then treated to separate the solids from the liquid as by filtration or centrifuging. The separated solids C may be washed and used wet or dry, with or without further comminution. The separated liquid is then treated, as by acidification, to precipitate proteinaceous and other materials. The resulting precipitated solids are then separated from the liquid as by filtration or centrifuging, for example in a solid bowl centrifuge. This separated liquid may be discarded or further processed to recover unprecipitated proteinaceous or other materials therein. The separated solids A containing a large proportion of proteinaceous material may be washed and used wet, or after drying with or without further comminution.

Fig. 2 is a flow diagram illustrating another process according to the present invention. The steps of mixing the solvent-wetted residues with an aqueous liquid, preferably an alkaline solution, to form a mixture of the desired pI-I value, and the removal of solvent from the resulting mixture are similar to those described in connection with Fig. 1. However, in the process illustrated in Fig. 2, the desolventized mixture, containing solids wetted with the aqueous liquid and colloidally dispersed and/or dissolved materials, is treated, as by acidification, to precipitate proteinaceous and other precipitable materials in the presence of the solids. The resulting mixture of solids and aqueous liquid is then treated, as by filtering or centrifuging, for example in a solid bowl centrifuge, to separate the solids from the liquid. The separated liquid may be discarded or further processed to recover unprecipitated proteinaceous or other materials contained therein. The separated solids B comprisingprecipitated proteinaceous and other materials, and the solids, may be washed and used while wet or after drying, with 'or withoutfurther comminution. v

PRODUCTS OF INVENTION u Product A The Product A of Fig. 1, comprises thesolids precipitated from the solvent free, solid free aqueous liquid. This'product consists substantially entirely of proteinaceous material. It is free of cellular material, cortex, and other substances insoluble in or not colloidally dispersed in the aqueous liquid. The nature and yield of the proteinaceous material is largely determined by the nature of the original solvent-Wetted residues, the amount of aqueous liquid mixed with such residues, the pH of the mixture, and the pI-ll value at which the precipitation is carried out. A product produced under optimum conditions for maximum precipitation after drying to a point where it contains by weight from about 5% to about of water and other materials readily volatilizable at 110 C. will contain from about 14% to about 17% by weight of nitrogen. Substantially all of the nitrogen is combined in the proteinaceous material which comprises a diificultly analyzable mixture of different proteins of different nitrogen contents. The Ofii cial and Tentative Methods of the Association of Oflicial Agriculture Chemists, fourth edition, 1935, at page 335 directs the use of the factor 6.25 for converting the weight of nitrogen, found by analysis, to the approximate weight of protein. On this basis, it is apparent that Product A contains from about 87.5% to about 100% of proteinaceous material.

A preferred product of this type consists essentially of the proteinaceous materials which were soluble or colloidally dispersible in an aqueous alkaline solution of about 8-13 pH and preferably of about 10-12 pH; and which are preci itable by an acidic solution of about 3-6 pH and-preferably of a pH value at which the maximum era,

10 cipitation of prbteinace'ous material will occur. Since the proteinaceous material need never be heated to temperatures greater than about 60 (2., there is substantially no degradation of the material.

The product is whitein color and may be readily dispersed and/ordiss'olved in alkaline solutions, and, hence, is useful in emulsion-type paints, coating compositions for paper or other materials, adhesives and other compositions. To maintain the high degree of dispersibility, it is advantageous not to dry the product after its production. Products of this type may also be used as foods, or as fillers for plastics or other materials, or in fertilizers.

Product B Another type of product, corresponding to Product 13 of Fig. 2 comprises the initial solids and the solids precipitated from the solvent free aqueous liquid. The amount of proteinaceous material in the product is determined by adjustment of certain factors,"such as the amount of aqueous liquid, the pH of the initial mixture, and the pH during precipitation. A product produced from decorticatecl beans and seeds under optimum conditions for maximum precipitation and after drying to apoint where it contains by weight no more than about 5% to about 10% of water and other materials readily volatilizable at 110 C., will have the following typical approximate composition by "weight.

745% nitr'ogen' I 10-25% cellular material 5-10% moisture and substances volatilizable at In the case of undecorticated beans or seeds, the product willhave the following typical approximate composition by weight:

4%8% nitrogen 50%- cellular material and cortex 5%-10% moisture and substances volatilizable at 110 C.

Substantially all ofthe nitrogen in each case is combined .in proteinaceous materials. Converting by the factor 6.25, it is apparent that the first product will contain from about 40% to about by weight of proteinaceous material, and the second product will contain from about 25% to about 50% by weight of proteinaceous material.

A product of this type contains these proteinaceous materials which are insoluble in aqueous liquids of about 8-13 pH and those soluble proteinaceous materials which are precipitable by converting the pH value to that at which maximum precipitation of proteinaceous materials occurs.

At no stage in the process need the product be heated to a temperature above about 60 C., so that the product contains substantially undegraded materials. v

This product, preferably after comminution, may be employed for the purposes indicated above for Product A. If used in emulsions, it is advantageous to use a product which has never been dried. Since the presence of the cortex and cellular material tends to impart a brown coloration to the product, it may not be as desirableforuse in paints or coating materials as Product i v Product C Thepr oduqh, corresponding to Product C of Fig. -1, comprises the "solids separated from the solvent-free mixture prior to the precipitation step. Such solids contain cellular material, cortex, if present in the original residue, and proteinaceous materials not solubilized by the aqueous liquid. The amount of proteinaceous material present is dependent upon the pH of the initial mixture, but in any event is much less than in Products A and B.

When a product produced from decorticated beans and seeds is dried to a point where it contains no more than from about to about by weight of water and other materials readily volatilizable' at 110 C., it will have the following typical approximate composition by weight:

0.8%-10% nitrogen 35%-85% cellular material 5%-10% moisture and substances volatilizable at 110 C.

In the case of undecorticated seeds and beans, the product will have the following typical approximate composition by weight:

0.4%-4.0% nitrogen '75%-97% cellular material 5%10% moisture and substances volatilizable at 110 C.

In each of these products, substantially all of the nitrogen is combined in proteinaceous material. Upon conversion by the factor of 6.25, it is apparent that the first product contains from about 5% to about 63% by weight of proteinaceous material, and the second product contains from about 2.5% to about by weight of proteinaceous material.

After washing and preferably after comminution, the product may be used as a binder, filler for plastics or other materials, as a fertilizer and, in some cases, as stock food.

EXAMPLES The following examples illustrate processes and products embodying the invention. Such examples are given only for illustrative purposes and the invention is not to be limited thereto.

Example 1 The starting material was the solvent-wetted residue resulting from the extraction of oil with heptane from decorticated and crushed castor beans. The heptane-wetted residues contained approximately 50% heptane and 50% solids by weight. The solids analyzed 11.2% nitrogen by weight (corresponding to approximately 70% proteinaceous material when calculated as nitrogen 6.25) and the balance was finely divided cellular material and water-soluble compounds. These residues were deposited in a high shear mixing vessel and a solution of sodium hydroxide of 11.0 pH was slowly added while mixing .until a free-flowing slurry was obtained. This slurry was recirculated from a kettle through a pump and back to th mixing kettle while more of the alkali solution was added until a total of about 17.5 pounds of water to each pound of heptane-wetted residue was added. The mixture was then injected in a thin stream into the upper portion of a closed kettle in which a vacuum of about 28 inches of mercury was maintained and which was heated with direct steam to a temperature of about C,.; solvent vapors together with some water vapors flashed on the injected falling stream. Heating with direct steam was continued until a vapor tem perature of about 35 C. was reached. The mixture in the kettle was continuously agitated by recirculation of the mixture from the lower portion of the kettle, through a pump, to the upper portion of the kettle to produce a splashing effect by the falling stream. At this point a sample was withdrawn from the kettle and was observed to have the desired settling characteristics; i. e., the solids settled in the liquid. Meanwhile, the solvent vapors evaporated from the mixture, together with some water vapor, were withdrawn from the kettle through the vacuum pump and condensed at atmospheric pressure by cooling. The heptane was separated from the water for reuse in the solvent extrac tion process. After the solids were found to settle out, the kettle was returned toatmospheric pressure. A 5% aqueous solution of sulfuric acid was slowly added to the mixture while agitation was continued by recirculating the mixture through the pump. The acid was added until a sample was found to have a pH value of about 3.9. The solids in the mixture now comprised cellular materials and other solid materials initially present, as well as proteinaceous and other materials precipitated by the acid. The liquid contained soluble proteinaceous and other materials. The solids were then separated from the liquid by filtration, washed with 'water acidified to 3.9 pH, incompletely dried and pulverized.

The solids contained about 13.4% of nitrogen (equivalent to 86.3% proteinaceous material calculated as nitrogen 6.25), the balance being largely the finely divided cellular components of the original decortlcated castor bean. The proteinaceous material included both the alkali-insoluble proteinaceous material of the residue and that portion of the alkali-soluble proteinaceous materials which was precipitated by the acid.

The product dispersed readily in various aqueous alkaline solutions and is useful as a base for emulsion paints, coating materials, adhesives and for other purposes.

Example 2 Heptane-wetted castor residues from decorticated castor beans, of the kind described in Example 1, were desolventized under the conditions set forth in Example 1. The desolventized mixture was then centrifuged in a solid bowl centrifuge to separate solids from liquids. The separated solids, after neutralization with acid and drying, contained about 1.1% nitrogen (equivalent to 6.87% proteinaceous material calculated as nitrogen 6.25), the balance being largely cellular material. These solids were found to be useful as a fertilizer and as filler materials for plastics.

The clear liquid separated from the solids in the centrifuging operation was then acidified by the addition of 5% solution of sulfuric acid to the point of maximum precipitation (about 3.9 pH), de-watered by decantation and washed with water acidified to 3.9 pH. The precipitated solids were then separated from the liquid by filtration, incompletely dried and pulverized. The resulting product contained 16.1% nitrogen by weight (approximately proteinaceous material calculated as nitrogen 6.25). It was easily dispersible in alkaline solutions and is useful as an emulsion base for paints, coating materials, as a hinder or adhesive, and as a filler for plastics and the like.

Example 3 in the residue analyzed6.1-% nitrogen (equivalent to 38.1% proteinaceous material calculated as nitrogenX 6.25). To the heXane-wetted meal in a high shear mixing vessel water was addedin proportions of 25 parts of water to each-part of solvent-wetted meal by weight. The relatively large amount of water was used to obtain a workable slurry in view of the high proportion of mucilages present in the meal. Suificient caustic soda was added to give the mixture a pH value of about 11. The mixture was thoroughly agitated and mixed by recirculating through a pump.

The mixture was then heated in a desolventizing vessel under theconditions outlined in Example 1. When a temperature of 35 C. was obtained, the solids ina withdrawn sample were Example 4 Heptane-wetted residues of'the kind described in Example '3 were mixed with alkali solution and desolventized as insaidexample. The desolventized mixture was then subjected to a separating operation by centrifuging in a solid bowl centrifuge. The separated solids, after washing, 4 were dried and pulverized; they comprised largely cortex, cellular material, and about 11.2% by weight of alkali-insoluble proteinaceous material. These solids are useful as a stock feed, fertilizer, Or binding material.

The liquids separated during the centrifuging operation were treated with 5% sulfuric acid solution until a pH value of about 3.5 was reached; a considerable precipitation occurred. The precipitated solids were then separated from the liquids by a solid bowl centrifuge, and were then washed with water acidified to 3.5 pH, dried and pulverized. The pulverized product contained 15.4 nitrogen (approximately 96.25% proteinaceous material calculated as nitrogen 6.25). The product was found to have excellent color and dispersed readily in alkaline solutions. It is useful in paints, coating materials, adhesives, as a filler, and as a food.

Example 5 The process of this example is identical with that of Example 1, except that the solids separated from the liquid by filtration were not dried. The filter cake was washed on the filter and then removed; it contained by weight 17.5% solids and 82.5% water. The solids contained about 13.5% of nitrogen (corresponding to about 87% proteinaceous material calculated as nitrogen 6.25).

The resulting product was then formed. .into an emulsion without ever having'been dried. .To 540 ,parts by weight .of this water-wet ,product was added 20 parts of rosin ,and .20 partsof linseed fatty acids, and the whole was heatedat about F. for .30 minutes While .being agitated. Then 10 parts vof a sodium .salt .of va chlorinated phenol was added as'a preservative and the temperature was raised to about To the resulting mixture was added .8 parts of borax and sufiicient ammonium hydroxide to raise the pI-I value .to 9,. The resulting dispersion was then heated to about F. for45rminutes, cooled and readjusted to a pH value of ,9 with ammonium hydroxide. ,It was ,found 130 be excellent for use .as a base for emulsion paints orpaper coating materials. For the ,production of such compositions, pigments, oily vehicles 'or other desired components can be incorporated in the dispersion during or after its preparation.

It was also found that the water-wet pro-- teinaceous product could be stored wet for long periods of time without deterioration, particularly when it contained a protein preservative,

such as the chlorinated phenol mentioned above- The present invention thus provides processes by which solvents may be rapidly,-efiiciently and economically recovered from solvent-wetted residues remaining after solvent extraction of oils from oil-containing vegetable materials, which processes do not require the use of high temperatures which would deleteriously affect proteinaceous materials in the residues. The processesproduce ,at a low cost useful and valuable products of highly desirable properties :from such residues. Such processes may be carried out in conventional equipment.

The present invention also provides novel products containing high proportions of proteinaceous materials having highly desirable properties.

It is apparent that the solvent-wetted vegetable residues employed as the starting material need not necessarily be those resulting from solvent extraction of vegetable materials to re-' move oils therefrom. Moreover, the solventwetted residues may be mixtures of diiferent solvent-wetted residues; thus, they maybe mixtures of residues of different vegetable materials, or residues wetted with different solvents. Also dispersing and precipitating agents other than those indicated may be employed.

The above description of the invention is merely illustrative and the invention is to be limited only by the scope of the appended claims.

What is claimed is:

1. The process for removing oil-miscible solvents from solvent-wetted vegetable residues containing proteinaceous constituents, comprising mixing a solvent-wetted residue with an aqueous liquid to form a slurry, and evaporating the solvent from said mixture at a temperature below that at which degradation of the proteinaceous constituents will occur.

2. A process for removing oil-miscible solvents from solvent-wetted vegetable residues while preventing degradation of the proteinaceous constituents of said residues comprising mixing a solvent-wetted residue with an aqueous liquid to form a slurry having a pH value of from about 5 to about 13 and evaporating the solvent therefrom at a temperature below that at which degradation of the proteinaceous constituents will occur.

3. A process as claimed in claim 2 wherein 15 the mixture has a pH value of from about 5 to about 8.

4. A process as claimed in claim 2 wherein the mixture has a pH value of from about 8 to about 13.

5. A process as claimed in claim 2 wherein the mixture has a pH value of from about 10 to about 12.

6. A process for removing oil miscible solvents from solvent-wetted vegetable residues containing proteinaceous material comprising mixing a solvent-wetted residue with an aqueous liquid to form a slurry, heating the mixture while under a partial vacuum, to a temperature below that which will degrade the proteinaceous material to evaporate substantially all of the solvent therefrom.

'7. A process as claimed in claim 6 wherein the mixture has a pH value of from about 10 to about 12 and wherein the mixture is heated to a temperature not higher than about 60 C.

8. A process for treating solvent-wetted vegetable residues containing proteinaceous materials comprising mixing a solvent-wetted residue with an aqueous liquid to form a' slurry of solids in liquids having a pH value at which at least a portion of the proteinaceous material will be solubilized in said liquids, evaporating substantially all of the solvent from said mixture at such temperature and pressure that the degradation of the proteinaceous material therein will be prevented, and changing the pH value of the desolventized liquid to precipitate at least a portion of the solubilized proteinaceous material.

9. A process as claimed in claim 8 wherein the mixture of solvent-wetted residue and aqueous liquid has a pH value of from about 5 to about 13 and wherein the pH value of the desolventized liquid is lowered to precipitate solubilized proteinaceous material from said liquid.

10. A process as claimed in claim 8 wherein the aqueous liquid is alkaline and the mixture has a pH value of from about 8 to about 13 and wherein the pH value of the desolventized liquid is lowered to a value of from about 3 to about 6 by the addition of an acidifying reagent whereby substantial amounts of the solubilized proteinaceous material is precipitated.

11. A process for treating solvent-wetted vegetable residues containin proteinaceous materials comprising mixin a, solvent-wetted residue with an aqueous liquid to form a slurry of solids in liquids having a pH value at which at least a portion of the proteinaceous material will be solubilized in said liquids, evaporating substantially all of the solvent from said mixture at such temperature and pressure that degradation of the proteinaceous material therein will be prevented, separating the solids from the desolventized liquid, and changing the pH value of the substantially solid-free desolventized liquid to precipitate at least a portion of the solubilized proteinaceous material.

12. A process as claimed in claim 11 wherein the mixture of solvent-wetted residue and aqueous liquid has a pH value of from about 5 to about 13 and wherein the pH value of the desolventized liquid is lowered to precipitate solubilized proteinaceous material from said liquid.

13. A process as claimed in claim 11 wherein the aqueous liquid is alkaline and the mixture has a pI-i value of from about 8 to about 13 and wherein the pH value of the desolventized liquid is lowered to a value of from about 3 to about 6 by the addition of an acidifying reagent whereby substantial amounts of the solubilized proteinaceous material is precipitated.

14. A process for treating nolvent-wetted vegetable residues containing proteinaceous materials comprising mixing a solvent-wetted residue with an aqueous liquid to form a slurry of solids in liquids having a pH value at which at least a portion of the proteinaceous material will be solubilized in said liquids, evaporating substantially all of the solvent from said mixture at such temperature and pressure that degradation of the proteinaceous material therein will be prevented, changing the pH value of the desolventized liquid to precipitate at least a portion of the solubilized proteinaceous material and removing a substantial amount of the liquid from the solids and precipitated proteinaceous material.

1 HAROLD F. SAUNDERS.

REFERENCES CITED The following references are of record in the file of this patent: