GB1572608A - Process for recovering useful products from molasses - Google Patents

Description

PATENT SPECIFICATION

( 11) 1 572 608 ( 21) Application No 43212/78 ( 22) Filed 25 May 1976 ( 19) ( 62) Divided out of No 1572607 ( 31) Convention Application Nos 4 582 809 ( 32) Filed 2 June 1975 680721 27 April 1976 in ( 33) United States of America (US) ( 44) Complete Specification published 30 June 1980 l ( 51) INTCLY C 13 D 3/14 ' ( 52) Index at acceptance C 6 B 2 ( 54) PROCESS FOR RECOVERING USEFUL PRODUCTS FROM MOLASSES ( 71) We, INGREDIENT TECHNOLOGY CORPORATION, of 120 Wall Street, New York, New York State, United States of America, a Corporation organised under the laws of the State of New York, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following

statement: -

This invention relates to the recovery of the carbohydrate fraction, as well as other useful products, from carbohydratecontaining products, particularly molasses, and is related to the invention disclosed in the complete specification of our copending U K patent application No 21707/76 (Serial No 1572607).

The art has long been aware that a host of carbohydrate-containing products exist from which can be derived all or part of the desirable carbohydrate content thereof.

Products such as fruit juices, cane and beet sugar juices, starch hydrolysates, hardwood sulfite liquors and whey present attractive source materials for carbohydrates such as sucrose, fructose, glucose, invert sugar, lactose and xylose In many cases, however, the low efficiency of prior art separation processes has not justified the expense typically encountered in such methods Compounding this economic disadvantage has been the inability to obtain additional useful products from these source materials, and hence offset the costs of carbohydrate recovery, without the need for still further extensive separation techniques.

The foregoing problems are particularly acute in the field of sugar refining where enormous quantities of " by-products " such as molasses result from the sucrose production process While molasses is known to contain many useful products, including sucrose, fructose, glucose, invert sugar and inorganic salts, attempts to recover these have been hampered by the inability to achieve any economically significant removal of these valuable pro 50 ducts.

The production of sugars such as refined sucrose may begin with either sugar cane or sugar beets as source materials therefor.

While processing steps designed to yield 55 substantially pure sucrose differ depending upon the sugar source utilized, a common by-product of these processes is molasses.

Molasses may be generated at a number of places in the overall sugar process and 60 is not, therefore, of any absolutely fixed composition As understood by the art, however, molasses is used generally to define the mother liquor remaining after sucrose has been crystallized out of solu 65 tion Molasses will generally contain sucrose, glycose and fructose, inorganic salts, and organic non-sugar compounds.

The composition of molasses will depend upon processing conditions, the particular 70 sugar source utilized, and the point in the process from which the molasses is taken off.

While not limited by definition, molasses typically and practically defines a sugar 75 solution wherein, due to the depletion of sucrose, the build-up of non-sucrose solids, and the increased viscosity of the mother liquor, it is no longer possible to crystallize sufficiently pure sucrose therefrom 80 This type of molasses is generally referred to as " final molasses " or " blackstrap molasses " Final molasses has found some useful outlets For example, it has been utilized as a source of yeast, vinegar and 85 various organic chemicals, such as alcohols, through fermentation However, technological advances resulting in the more economic synthesis of these products has minimized the importance of molasses as 90 io I"d 1 572 608 a chemical source While final molasses is not generally considered suitable for human consumption, molasses generated from earlier stages in the operation of sugar factories (e g first and second molasses) have been used for many years as food and as components of bakery and confectionary items Rarely, however, are molasses used in foods in such quantities as to afford a significant market for the vast quantity of molasses produced in sugar factories.

By far the major use for molasses such as final or blackstrap molasses is as a direct feed for ruminant animals and as a raw material for feed compositions However, in excessive amounts molasses acts as a laxative, thus being a limiting factor for daily consumption.

In some areas of the world molasses has found use as a fertilizer However, this use of molasses has proven to be economic only in those areas where there is no ready market for molasses Molasses from beet sugar processes have long been treated to remove sugars therefrom The most widely utilized process for desugaring is the Steffen process involving the addition of lime to a dilute molasses solution While the Steffen process is generally capable of recovering up to 95 % of the sugar in beet molasses, it is not generally applicable to the treatment of cane molasses because the process substantially destroys invert sugar Moreover, the Steffen treatment of beet molasses, resulting as it does in only a single product stream-sugar-fails to fully utilize other valuable components of molasses Still further, raffinose, which leads to errors in the polarization analysis for sucrose and adversely influences sucrose crystal growth, is built-up to a large extent in the Steffen process The art has therefore generally resorted to discharding molasses in Steffen factories for 24 hour periods every one or two weeks This " discard molasses " is yet another source of molasses requiring an economical outlet.

The prior art has also recognized the general utility of applying the principle of ion-exclusion in separating sugars from feedstocks such as molasses See, for example, U S Patent No 2,937,959 to Reents, et al, issued May 24, 1960 Difficulties are encountered, however, in treating molasses such as blackstrap wherein the effectiveness of the exclusion resin progressively decreases with time Moreover, considerable problems arise in attempting to practice these techniques on a commercial scale.

The present invention provides a process for treating molasses to recover useful products therefrom, comprising the steps of:

a) removing organic non-sugar material from the molasses by adding ferric ions to a molasses solution and removing the precipitate formed thereby; b) passing the thus treated molasses solu 70 tion through an ion exclusion resin material capable of preferentially absorbing sugar from the solution; c) thereafter passing water through said resin; and 75 d) separating the resulting effluent into a first fraction comprised largely of salts:

a second fraction comprised of a mixture of salts and sugars;and a third fraction comprised largely of sugars 80 In carrying out a process as set forth in the last preceding paragraph we prefer that said molasses solution is at a temperature of between 60 'F to 120 'F upon the addition of ferric ions 85 In carrying out a process as set forth in either one of the last two immediately preceding paragraphs we prefer that ferric ions are removed from the molasses solution after removal of the precipitate there 90 from, said removal of ferric ions comprising adding a phosphate-containing material to the molasses, and thereafter raising the p H of the molasses to above 7 0.

In carrying out a process as set forth in 95 any one of the last three immediately preceding paragraphs we prefer that the molasses having the precipitant removed therefrom is thereafter treated to remove high molecular weight material, therefrom 100 prior to passing through the ion exclusion resin, said removal of high molecular weight material comprising passing said molasses through a membrane filter.

In a specific embodiment of this in 105 vention, viscosity variations are imposed upon the feed solution to the exclusion resin in order to substantially reduce the incidence of channelling or other flow disturbances within the column Chanelling, 110 literally the establishment and consequent following by the feed material of distinct selected flow paths in a packed column, results in a by-pass of a large portion of the active sites of the exclusion resin and 115 the concomitant decrease in the efficiency and the degree of carbohydrate isolation and separation.

Where it is desired to recover the sucrose fraction from a sucrose-containing source 120 material, it has additionally been discovered that the exclusion resin utilized must not be in the hydrogen form since this will cause inversion of the sucrose to invert sugar 125 Molasses, particularly blackstrap molasses, owing to its viscosity and the host of non-sugar impurities contained therein has proven in the past to be only minimally susceptible to typical separatory techniques 130 1 572 608 In accordance with one feature of this invention, it has been discovered that the effectiveness of the ion-exclusion resin in separating the molasses into useful component is greatly enhanced by the removal of a significant amount of the organic nonsugar material from the molasses prior to its passage through the exclusion resin.

The prior art has heretofore largely relied upon the resin itself to separate out these materials since they are generally of a higher molecular weight than sugar and are therefore excluded from the resin particles However, we have found that the preliminary efficient removal of such materials is of significant importance in achieving a high degree of separation in the resin bed.

It has also been discovered that the addition of ferric ions, preferably in the form of ferric chloride or ferric sulfate, to the source molasses results in a highly effective removal of material in the form of a precipitate which would otherwise hinder the ion-exclusion process.

It has also been found that the particular resin material and the physical characteristics of the resin bed play an important role in achieving effective separation of sugars and salts Thus, for example, it has been found that typical resins comprised of a sulfonated styrene-divinylbenzene polymerizate having a cross-linkage or percent of divinylbenzene in the sodium form significantly higher than that heretofore utilized, e g, at least about 4 % are particularly useful for separating molasses, especially blackstrap molasses It appears that the added bed strength is an important separation factor for these materials In general, greater degrees of cross-linking may be successfully employed, e g, up to and including about 8 % divinyl benzene.

As the degree of cross-linking increases, however, the throughput capacity of feed through the resin decreases.

Moreover, the ratio of the exclusion column height to its diameter, as well as the size of the resin particles and the respective temperatures of the molasses solution and the follow-up water, all affect the effective separation.

The effluent from the ion-exclusion resin exits therefrom in distinct fractions predominating in one or more useful materials, at least one of which is the carbohydrate contained in the source materials, i e.

sucrose, when molasses is treated The effluent fractions may therefore be more effectively used for a variety of purposes thereby enhancing the near complete utilization and marketability of the source molasses.

Membrane filtration, commonly referred to as ultrafiltration, techniques can be utilized, in addition to use of ferric ions, to remove a significant portion of organic non-carbohydrate compounds, typically color bodies or precursors thereof, from the carbohydrate-containing source material 70 This clarification technique may be utilized either prior to exclusion/separation or as a means of further clarifying the carbohydrate-rich fraction obtained from the ion exclusion treatment 75 As used herein, the term " molasses " is intended to encompass all forms of the liquor from which sucrose is crystallized or crystallizable Thus, the term is inclusive of whole juice molasses; "first 80 molasses ", i e the mother liquor remaining after the first crysallization of sucrose therefrom even though crystallizable sucrose remains in the liquor, and all subsequent liquors remaining after crystallization The 85 term further includes " final " molasses or that mother liquor which, owing to its viscosity and large concentration of impurities such as ash, non-sucrose sugars, and organic non-sugars, is for all practical and 90 economic purposes no longer capable of yielding sucrose upon crystallization Moreover, molasses is intended to embrace the above products irrespective of the source of the molasses, i e, be it from a sugar 95 cane or sugar beet process, or from which point in the process it is generated and taken off Thus, the term includes first, subsequent and final molasses generated in the crystallization of sucrose in raw cane 100 sugar processing; the molasses recovered in the affination of sucrose crystals containing a thin film of molasses during the refining operation; " refining molasses " produced in the sucrose crystallization process 105 practiced in the cane sugar refining operation; beet molasses from the sucrose crystallization from beet sugar solutions; and " discard " molasses from the Steffen process 110 Ion exclusion is now a fairly well-known process and has been suggested generally for use in the sugar industry Rather than involving the exchange of ions, the exclusion resins achieve a physical adsorption of 115 one or more components to the exclusion of others Thus, for example, a cation exchange resin will display a more prominent affinity for a weakly ionizable material (such as sugar) permiting the material to 120 be adsorbed on the resin while more highly ionizable materials such as inorganic salts remain in the surrounding or interstitial fluid Upon passing water through the resin bed, a solution of the highly 125 ionizable material will appear first, followed eventually by the physically adsorbed weakly ionizable material The resin so utilized is referred to hereinafter as the ion exclusion resin 130 1 572 608 In the application of ion exclusion to molasses, chanelling problems are prevalent which result in very low efficiency separations These problems, while often encountered in processes involving the flow of a liquid through a packed column, become attenuated in exclusion processes due to the peculiar physical nature of the resin bed and the fact that efficient exclusion requires the throughput of at least two liquid streams-feed material and follow-up liquid such as water In accordance with this invention, these problems are largely eliminated, and hence exclusion efficiency increased, by using one or more techniques peculiarly applicable to exclusion processing In one embodiment, channelling or "leap-frogging" as hereinafter described, is materially reduced by introducing the molasses solution into the exclusion column in an incremental manner such that the viscosity of the source solution may be varied In particular, a typical molasses feed to the exclusion column would have a density in the range of about 45-550 Brix It is found that when followup water is introduced thereafter to elute the various fractions, the water, being of considerably lower viscosity than the molasses feed, will migrate through the exclusion column at a rate in excess of the rate of molasses through-put As the water mingles with and eventually by-passes or "leap-frogs " the molasses both the ability of the resin to adsorb sugar and the ability of the water to extract and elute both adsorbed and unadsorbed material are markedly diminished.

The foregoing "leap-frog" condition is extremely pronounced in exclusion columns having low height to diameter ratios, i e, where the vertical distances between the various fractions are small In the operation of a commercial scale unit in which maximum throughput is desired, the use of low height to diameter ratios in the order of 0 8 to 5 0 is preferred Hence the foregoing flow problems attenuate on a commercial scale.

It has been discovered that the otherwise attendant leap-frog problem may be significantly reduced or eliminated by utilizing a sequential feed to the exclusion column compirse of at least two portions of the feed material of differing viscosity A first portion consists of the normal feed to the column, e g for molasses, a feed at 45-60 Brix The second sequential feed portion has a viscosity (i e lower Brix value) lower than that of the first portion A dilute aqueous medium such as water or a dilute molasses solution is then sequentially added to elute the various product solutions from the exclusion column The viscosity difference between this eluting medium and that of the second feed portion, being smaller than would be encountered utilizing a feed of constant viscosity, serves to prevent the eluting medium from bypassing the feed material 70 In a preferred embodiment, three or more distinct portions of the ferric ion treated molasses feed are sequentially employed The first portion of the molasses feed to the column comprises a low density 75 solution thereof, e g, from 15 to 25 Brix.

The next sequential addition comprises molasses having a higher density, typically from 45 to 550 Brix This is then followed by a third feed portion having a density 80 in the range of 15 to 250 Brix This is then followed by a third feed portion having a density in the range of 15 to 25 Brix.

Thus, the typical feed, i e 44-55 Brix molasses is buffered or cushioned with low 85 density molasses.

The follow-up water or other dilute aqueous sluotion is then fed to the column to elute the various product fractions This rinse may be accomplished using either 90 water or a dilute solution of no more than about 50 Brix density, or a sequential mixture thereof It is found that the buffer or cushion zones about the high density molasses feed serve to minimize, and 95 generaly eliminate, the tendency of the rinse fraction to mingle with or bypass the molasses In this manner, suitable residence times are permitted for appropriate adsorption by the exclusion column and sequential 100 elution of the various product streams.

The amounts of the various components of the feed material necessary to provide a suitable buffer zone around the high density molasses feed may vary consider 105 ably based upon the design of the column, the density of the buffer layers and feed and other like considerations In general, however, the amounts (measured as bed volumes) of each buffer should be approxi 110 mately the same as the high-density molasses feed, and typicaly from 0 8 to 2 5 times the amount of the high-density fraction.

As will be apparent to those skilled in 115 the art, relative densities, viscosities or concentrations are directly inter-related and may be looked upon as alternative means for expressing viscosity or flowability differences between the various portions 120 Thus, while Brix is a density measurement, it will be understood that, for example, higher values connote solutions of higher viscosity (and concentration).

An additional method which may be 125 utilized either alone or, preferably, in conjunction with the foregoing viscosityvariation method is to pass the water or other dilute solution used to wash the various materials from the column, i e, the 130 1 572 608 follow-up water, through the bed at a temperature below that at which the source material was fed Preferably, this temperature differential should be in the order of at least about 20 degrees measured on a Farenheit scale In a particularly preferred embodiment, where the earlier-described feed density variations are utilized, the temperature of the low density buffer components of the feed are maintained at temperature lower than that of the high-density feed portion This mode of operation minimizes both the mingling of the interfaces of the feed components and the tendency of the rinse fractions to bypass the feed portions.

To a considerable extent, the efficiency of the ion exclusion separation is dependent, for molasses, upon the effective pre-treatment thereof to remove organic non-sugar compounds Since molasses poses the most significant problems in this respect owing to its large amount of organic non-sugars, typically color compounds or their precursors.

In accordance with this invention, molasses is first treated with ferric ions to remove organic non-sugar materials in the form of a precipitate The precipitate is removed by appropriate means to leave a clarified molasses solution largely devoid of the colors caused by the presence of these organic materials.

The iron-containing compound, preferably Fe CI 3 or Fe A( 50)3, is added to a molasses solution These ferric salts, along with other like materials, form complexes with impurities in the molasses solution with the result that a floc is formed capable of settling to the bottom of an appropriate vessel and carrying therewith a large portion of the organic non-sugar impurities.

ily The degree of floc formation and organic non-sugar/color removal is primarily a function of the solution p H and its solids concentration Using iron-containing compounds as an example, and a feed material of final cane molasses (blackstrap molasses), floculation/precipitation is noted over a wide range of p H on the order of 2 0 to 9 0, precipitation and removal from the molasses solution being achieved to varying degrees within this range The most efficient precipitation and color removal and the most desirable color in the remaining supernatent molasses solution is achieved over a preferred range of p H 2 0 to 3 0 and most preferably a p H of 2 1 to less than 2 5 Since most molasses have an initial p H of 5 5 to 9 0, some most molasses have an initial p H of 5 5 to 9 0, some degree of p H adjustment prior to addition of the floculant will be necessitated in most cases Any suitable acidic material such as hydrochloric acid may be used to obtain the desired p H.

Where iron-containing compounds are employed as the precipitating additive, it has been determined that the molasses solution should be of a relatively dilute 70 concentration to enhance floc formation.

The molasses solution is preferably below about 30 % solids by weight and most preferably from about 5 % to 25 % solids by weight Excellent color removal has been 75 accomplished using a 10 % solids solution and either ferric chloride or ferric sulfate.

The temperature of the molasses during this clarification with ferric ions is not believed to be of critical importance but 80 is subject to considerations of the viscosity of the molasses and the consequence ease of precipitation of organic non-sugars.

Preferred temperature are in the range of F to 180 F, and most preferably, par 85 ticularly for basic solutions, from 160 F to 180 F For acidic solutions, a preferred temperature range is from 60 F to 120 F.

The amount of precipitating additive utilized may vary over a wide range, de 90 pending largely upon the additive utilization, the solids concentration of the molasses to be treated, and the amount of organic impurities contained therein.

Amounts of ferric compounds from 1 to 95 % by weight of the solids have been employed and preferred ranges vary from about 3 % or greater, most preferably 6-15 % for Fe CI 3 and about 22 % for Fe( 501)3 In general it appears that the 100 color of the supernatent molasses solution improves with increasing amounts of additive.

The precipitate formed in the abovedescribed step may be removed by any 105 number of means, depending to some degree upon the additive used and the type of precipitate formed Procedures such as filtering have been successfully utilized In our preferred embodiment wherein iron 110 containing compounds are used as the precipitant, a preferred process after removal of the above-described precipitate, involves thereafter raising the p H to above 7 0 to precipitate iron compounds Calcium oxide 115 or hydroxide is exemplary of the materials useful for this purpose Indeed, the foregoing procedure has been found to yield a further precipitate resulting in additional color removal An optimum range of p H 120 is from 7 5 to 8 6 and preferably 8 1 Any iron remaining in solution may be removed by the addition of suitable materials such as inorganic phosphates, preferably sodium or calcium phosphates A preferred 125 material is monocalcium phosphate The amount of these materials needed to effect substantial iron removal may vary widely and is easily determinable by those skilled in the art For example, amounts from 130 1 572 608 2 % to 6 % of monocalcium phosphate by weight of the solids in solution in a slightly basic medium afford near complete iron removal.

Owing to the desirability of using molasses solutions of relatively low solids concentrations in this precipitation step, subsequent concentration, e g by evaporation, may be practiced to achieve a higher solids content Evaporation to about 60 Brix may result in the formation of a further precipitate which may be removed in any conventional manner Further concentration, if desired, may then be resumed.

It is generally desired to remove 90 % or more of the color from the molasses solution and the above-described materials and conditions may be varied to achieve even greater color removal, i e, up to about 03 % removal.

In accordance with this invention, the effluent molasses resulting from the preliminary removal process, is passed through an ion exclusion resin The preliminary removal step is of importance since the presence of any significant amount of material capable of precipitation has been found to cause the ion exclusion resin to become coated with the precipitate and substantially diminish its effectiveness for preferential physical adsorption Hence, care should be taken to insure the substantial absence of such impurities If not removed in the clarification step, a suitable subsequent removal should be effected.

The ion exclusion resin may be of the cation or anion type, although a cation resin is preferred.

In accordance with one embodiment of this invention it has been found that the composition of the resin as well as the physical characteristics of the bed and process conditions are important factors bearing upon the efficient separation of the molasses Thus, we have found that a cation exchange resin comprises of a sulfonated styrenedivinylbenzene polymerizate having a cross-linkage or percent of divinylbenzene in the sodium form of about 8 % is preferred in separating molasses, especialy blackstrap molasses This degree of cross-linkage, generally higher than suggested in the art, imparts desirable strength to the resin Such a resin as abovedescribed is commercially available as Dowex (T M) 50 WX 8 (trade designation of the Dow Chemical Company) Another appropriate exclusion resin is sold under the trade designation Amberlite (T M) IR-120 Resins having a percent crosslinkage of 4-8 % have also been successfully utilized in the treatment of molasses and other carbohydrates-containing products.

Generally, cross-linking above about 8 % will too greatly reduce throughput capacity to be effectively utilized on a commercial scale.

We have also found that the height to diameter ratio of vertical cylindrical 70 columns used for contacting the resin will affect the quality and efficiency of the exclusion For resin bead particle sizes of 20-50 mesh (U S Sieve) the height to diameter should be at least 1 and preferably 75 from 3 to 50 For mesh sizes of 50 to 80, suitable ratios may range from 1 to 20.

In passing the molasses through the ion exclusion bed the flow rate should be controlled so as to result in the optimum 80 separation Since this separation is a result of physical adsorption, the flow rate should not, therefore, exceed the adsorption rate of sugar onto the resin For the above-mentioned cation exclusion resins, the flow 85 rate should preferably be below O 60 gal/ ftz/min.

The passage of molasses through the ex-clusion resin is followed by the passage of water through the bed The relative ratio 90 of follow-up water to molasses may be varied over a wide range and optimums are easily ascertainable with reference to the degree of removal of the adsorbed component from the resin and the concentra 95 tion of the effluent streams Preferably, the volume of follow-up water should be at least about twice that of the molasses, and typically from 2 to 3 times the molasses volume 100 If passed directly to a cation ion exclusion resin in the monovalent form, it is found that the separation of the molasses feed may become less effective with time, due, it is theorized, to the exchange of 105 calcium or other multivalent materials for monovalent ions in the ion exclusion resin.

Once calcium and the like appear at the exchange position, the composition of the resin is altered and the resin loses its 110 effectiveness for preferential adsorption.

Accordingly, the molasses may be first passed through an ion exchange softening column wherein calcium and other like multivalent ions are exchanged for mono 115 valent ions such as sodium For a cation exclusion resin, a preferred preliminary exchange bed is Amberlite IR-120 utilizing a molasses feed at 1800 F and 60 Brix or less The exchange phenomenon observed 120 may be similar to that described in U S.

Patent Specification No 2,937,959 To effect ion exchange, flow rates that are higher than those employed in the ion exclusion step may be used, for example, 125 flow rates of I to 2 gal/ft 2/min or even higher may be utilized.

For cation exclusion beds, the sugars in the molasses solution, e g sucrose.

fructose and glucose, are adsorbed by the 130 1 572 608 resin while the highly ionizable salts are excluded and remain in the interstitial areas Moreover, some extremely large (high molecular weight) color bodies, while organic and therefore non-ionizable, are too large to be adsorbed in the resin and hence remain in the surrounding liquid.

Upon the passage of water through the exclusion bed, a variety of effluent will appear which can be divided according to the composition and their elution time.

Typically, the first appearing effluent fraction will be a solution having less than about 1 % sugar by weight and whose solids are largely or predominantly ash (typically inorganic salts) Color bodies excluded by the resin due to their size will also appear in this fraction This fraction, while useful as a regenerant for the softening resin, may be evaporated to form a concentrated salt mixture finding use as a fertilizer.

Additionally, potassium salts may be crystallized out of the solution The second effluent fraction is typically a diluted solution of the feed molasses This fraction may be recycled for further separation.

However, upon evaporation, the fraction, being similar to molasses in composition, is useful as a ruminant feedstock Since it is produced in only fractional quantities its utilization for this purpose is not unduly restricted by the intake limitations to which reference was earlier made.

A third effluent fraction is a solution containing a large amount of sugar and extremely small quantities of ash and organic non-sugars This fraction may be evaporated to yield a useful sugar solution.

Removal of some residual color may be necessary in the treatment of this fraction.

A fourth fraction is a highly diluted sugar solution ideally suited for diluting source molasses where the preliminary precipitation or ion exclusion so required A final fraction is essentially colored water having little practical value.

In accordance with the foregoing procedures, an effluent stream of concentrated mineral salts, most notably potassium, is recovered and is ideally suited for use as a fertilizer A substantially pure sugar containing stream is recovered having to a substantial degree, where blackstrap molasses is used as the feed, the characteristics, properties and utilities of invert sugars Mixed compositions of salts and sugars, being thereby akin to normal molasses, can find direct use as an animal feedstock Advantageously, the beginning molasses is separated into product materials which can be used to their fullest extent based upon the current relative demands therefor with almost negligible waste.

There now follows a number of Examples (I to IV) illustrating methods of treating molasses to remove organic nonsugar material in carrying out a process according to the invention, and Examples (VVI) of carrying out a process according to the invention 70 EXAMPLE I

Blackstrap molasses from a cane sugar process was utilized in this run The blackstrap was diluted to 100 Brix and 12 % by weight (solids basis) Fe Cl 8 was added at a 75 p H of 2 5 The mixture was heated to 'F and filtered The p H of the supernatent was raised to 8 6 using 4 % by weight calcium oxide, heated to 160 'F and filtered.

The solution was then brought to a p H of 80 4.7 using H 3 PO and filtered 5 % by weight disodium acid pyrophosphate was then added, the mixture allowed to sit at 160 F for five minutes and then filtered The supernatent was then treated with 5 % by 85 weight KB carbon at 160 F for five minutes and filtered; thereby to remove organic non-sugar material.

The above procedure resulted in 97 3 % color removal from the feed molasses 90 EXAMPLE II

Blackstrap molasses was dilute to 100 Brix to which was added 18 % Fe Cla by weight (solids basis) The solution was heated to 160 F, filtered and then adjusted 95 to 8 1 p H with calcium oxide and refiltered to remove organic non-sugar material 90 % color removal was achieved.

EXAMPLE I Il

2032 grams of blackstrap at 10 50 Brix 100 is heated to 160 F, and 11 % by weight (solids) ( 23 43 grams) of Fe 2 ( 504)3 is added.

One gram ( 0 47 % by weight) of calcium oxide is then added followed by 11 % by weight Fe 2 ( 503)4 The solution is then ad 105 justed to p H 2 5 with calcium oxide The solution is then centrifuged The resultant supernatent is heated to 140 F and raised to p H 8 1 with calcium oxide This is followed by centrifuging and addition to 110 the remaining solution of 2 % by weight monocalcium phosphate The p H is adjusted to 8 0 and the mixture is centrifuged, thus removing organic non-sugar material.

Color removal was approximately 90 % 115 EXAMPLE IV pounds of blackstrap molasses was diluted to 500 Brix with 75 pounds of water The p H was lowered to about 2 5 by the addition of 13 % (by weight of solids) 120 of a 50 % solution of ferric sulfate This mixture was then diluted to 160 Brix and allowed to stand overnight after which the clear supernatent was decanted from the precipitate The supernatent was then 125 heated to about 160 F and passed through a 10 foot cylindrical column having a diameter of 1 0 foot containing 170 pounds of activated granular carbon (occupying 70 % of the column volume) at a rate of 25 130 1 572 608 gallons per hour.

To the thus treated product was then added 4 % (by solids weight) disodium pyrophosphate, heated to 150 'F and allowed to stand overnight A precipitate of organic non-sugar material occupying approximately 17 % by volume was formed.

The supernatent was removed and found to contain 29 color units per milliliter at 5000 A The original blackstrap, by comparison, contained 250 color units/ml.

EXAMPLE V

Clarified blackstrap molasses (clarified with ferric sulfate) at 8 4 Brix and a resistivity of 99 ohms was passed through a 5.1 centimeter diameter column containing 1160 cc of Amberlite XE-200 in the sodium form The temperature was 180 'F and the flow rate was maintained between 20 to 22 cc per minute.

Input Volumes:

Molasses Feed -1 29 Bed Volumes Water Rinse -0 60 Bed Volumes Output Fractions and Volumes:

First FractionWaste -0 13 Bed Volumes Second FractionRecycle -1 16 Bed Volumes Third FractionProduct -0 25 Bed Volumes Fourth FractionDiluted Product -0 35 Bed Volumes The third fraction, based on the original feed, represented 96 % color removal and 88 % by weight ask removal.

EXAMPLE VI lbs of blackstrap molasses was treated with 9 75 Ibs of ferric sulfate at 17 Brix and 3 2 p H The mixture, at 80 'F, was allowed to stand 24 hours after which the subernatent liquid was drawn off and used as feed to an ion exclusion column.

The ash content of the feed solution was 11.8 % by weight on dry basis This solution was passed through a 5 1 centimeter diameter column containing 1160 cc of Amberlite XE-200 in the ammonium form.

The temperature was 80 'F and the flow rate was maintained between 20 and 22 cc per minute.

Input Volumes:

Molasses Feed -0 39 Bed Volumes Water Rinse Feed -0 60 Bed Volumes Output Fractions and Volumes:

First FractionWaste -0 13 Bed Volumes Second FractionRecycle -0 45 Bed Volumes Third FractionProduct -0 22 Bed Volumes Fourth FractionDiluted Product -0 19 Bed Volumes Based on the original feed, color removal in the third fraction was 95 %; ash removal % by weight 65

Claims (4)

WHAT WE CLAIM IS: -

1 A process for treating molasses to recover useful products therefrom, comprising the steps of:

a) removing organic non-sugar material 70 from the molasses by adding ferric ions to a molasses solution and removing the precipitate formed thereby; b) passing the thus treated molasses solution through an ion exclusion resin material 75 capable of preferentially adsorbing sugar from the solution; c) thereafter passing water through said resin; and d) separating the resulting effluent into 80 a first fraction comprised largely of salts; a second fraction comprised of a mixture of salts and sugars; and a third fraction comprised largely of sugars.

2 A process according to claim 1 85 wherein said molasses solution is at a temperature of between 60 F to 120 F upon the addition of ferric ions.

3 A process according to either one of claims 1 and 2 wherein ferric ions are re 90 moved from the molasses solution after removal of the precipitate therefrom, said removal of ferric ions comprising adding a phosphate-containing material to the molasses and thereafter raising the p H of 95 the molasses to above about 7 0.

4 A process according to any one of claims 1 to 3 wherein the molasses having the precipitant removed therefrom is thereafter treated to remove high molecular 100 weight material therefrom prior to passing through the ion exclusion resin, said removal of high molecular weight material comprising passing said molasses through a membrane filter 105 A process of treating molasses to recover useful products therefrom according to claim 1 wherein step (a) is carried out in accordance with any one of Example I, II, III, and IV 110 6 A process of treating molasses to recover useful products therefrom according to claim 1 substantially as hereinbefore described with reference to either one of Examples V and VI.

ERIC POTTER & CLARKSON, Chartered Patent Agents, 5, Market Way, Broad Street, Reading RG 1 2 BN, Berkshire.

Printed for Her Majesty's Stationery Office by The Tweeddale Press Ltd, Berwick-upon-Tweed, 1980.

Published at the Patent Office, 25 Southampton Buildings, London, Wf J 2 A l AY, from which copies may be obtained.