Process for making polymeric complex from residual or by-product effluents from distilleries

A process for obtaining a polymeric complex from a by-product effluent obtained in a process for manufacturing alcohol by distilling a fermented aqueous sugar solution containing yeast. After distilling alcohol from the effluent a chemical or biological flocculant is added to the effluent to form a homogeneous mixture, which is heated to a temperature of at least about 80.degree. C. Yeast is removed from the heated mixture by a first decantation, then insoluble solids and muds are removed by a second decantation. The mixture is then concentrated by partially evaporating water therefrom to obtain an aqueous solution of the polymeric complex.

FIELD OF THE INVENTION
 This invention concerns a process for obtaining water-reducer, fluidizer,
 dispersant, tensio-active, adhesive and agglutinant agents from residual
 or by-product effluents which are produced by the result from distillation
 of concentrates used in alcohol manufacturing.
 BACKGROUND OF THE INVENTION
 The most commonly used process for industrial manufacturing of alcohol at
 distilleries comprises the following general steps:
 Admission and treatment (clearing, water dilution and sulphuric acid
 addition) of molasses from sugar cane processing plants.
 A fermenting step wherein the yeast is added to the diluted solution in
 order to ferment the sugars, as well as sulphuric acid to lower the pH of
 the diluted solution to about 3.7-4.5.
 Fermentation produces alcohols, particularly ethanol and non-fermented
 products.
 In alcohol distillation, approximately a 12 liters of residue per liter of
 alcohol is produced. A medium-sized distillery produces 50,000 liters of
 alcohol a day which is equivalent to 600,000 liters of residual effluents.
 This residue is highly pollutant due to its high oxygen chemical
 requirements (OCR) and oxygen biological requirements (OBR).
 Its qualitative composition is as follows:
 Water,
 Wornactive-out yeast remainders,
 Non-fermented products,
 Other organic products, ketones, medium or high molecular weight unmatched
 alcohols, which were eliminated during production due to toxicity.
 Products joined to the sugar or starch from the beginning of the process,
 as liquid compounds in the primary product (molasses or beetroot, barley,
 potato honeys etc.) in the form of non fermentable juices (sugars) which
 are incorporated into the main raw material in order to separate them
 later from the alcohols obtained.
 Sulphates and other sulphur compounds from the sulphuric acid reaction that
 were added for product clearing and pH control.
 Various cations either from the original plant or added as a part of the
 distillation process such as K,Na,Mg,Ca,Fe, etc.
 These effluents ferment almost spontaneously and produce very unpleasant
 sulphurous odors and due to their OCR and OBR are highly pollutant in
 their capacity for taking oxygen from the environment, affecting flora and
 fauna. A medium-sized distillery as aforementioned, which produces 50,000
 liters of alcohol a day has a contamination level equal to a city of
 500,000 inhabitants.
 At certain sites, where the distillery is located near plantations,
 residuals are used to irrigate these plantations.
 Nevertheless, this use is not considered appropriate due to the
 disagreeable odor which, they emit and high transport costs. The most
 common method for eliminating these residuals consists of uncontrolled
 disposal into rivers, seas and swamps causing severe environmental damage.
 SUMMARY OF THE INVENTION
 The residuals in their aqueous state and unconcentrated constitute a
 relatively large percentage (4%-15% in weight) in products which are
 polymers forming a polymeric complex, which comprises polysaccharide
 chains, saponin or sapogenin chains, phenolic and dextran group compounds
 as well as their salts.
 The main aim of the invention focuses on two objectives as follows:
 1) to eliminate contaminant products;
 2) to extract from them useful products which, are to be utilized in
 different industrial processes and which can also be marketed or re-used.
 In order to do this, residuals are treated to achieve the following
 purposes:
 A large volume of water to be re-used at the distillery;
 Products designed for industrial application derived from the different
 polymers utilizing their water-reducer or fluidizer, tensio-active,
 dispersant, adhesive and binding features.
 The balance varies from one distillery to other, concerning to the
 quantities and composition of raw materials being utilized, but it is near
 to:
 82% industrial water;
 14% dispersant, tenso-active, adhesive and industrial agglutinant agents,
 as an active component;
 4% precipitates.
 A part of the invention process concentrates the effluent and eliminates
 water-excess leaving up to 14% water which together with the 14% of active
 material aforementioned as dispersant, tensio-active, adhesive and
 agglutinant agents make an equal parts solution, that is, a 50% solution.
 The active component of the water-reducer, fluidizer, dispersant,
 tensio-active, adhesive and agglutinant agents is a certain polymeric
 complex having a molecular weight ranging from 700 to 150,000 gr/mol. Its
 structure is not well known.
 Generally, it has adhesive, dispersant and modifying surface tension
 properties in liquids and from them their main applications derived.
 Due to its adhesive properties such polymeric complex can be used in making
 ceramic and refractory products, in soil stabilization, in light aggregate
 manufacturing for civil construction, in adhesive manufacturing and other
 applications.
 Additionally, this polymeric complex can be used as water-reducer,
 fluidizer, dispersant and water-soluble anionic tensio-active agent and in
 this case it can be used in making dyes, insecticides, cement and concrete
 additives, in making moulded ceramic pieces, for stabilizing asphaltic and
 oil-water emulsions, micro-nutrient products for agriculture, cleaning
 products, industrial water treatment, in making batteries, in making dyes
 for photographic paper as well as in the tanning industry and crystal
 growing inhibitors.
 Usually, similar dispersants and tensio-active agents are obtained
 simultaneously with the cellulose after treatment of wood using a
 bisulphite process. The aforementioned products obtained from such a
 process entail certain drawbacks as for example:
 Many basic operations (milling, heating and separation) need to be carry
 out before attaining the lye containing dispersants, tensio-actives and
 agglutinants, which not only increases the cost of the whole process but
 also determines a performance reduction due to the numerous steps to be
 carried out.
 The lack of homogeneousness of dispersants, tensio-actives and agglutinants
 depends on the nature of the wood type, which at times may be very
 heterogeneous and creates serious problems in formulation adjustments.
 Now it has been found that it is possible to obtain water-reducers and
 fluidizers, dispersants, tensoactives and agglutinants by using a process
 which not only surpasses the above mentioned shortcomings related to the
 usual methods used to obtain these agents, but which also solves
 environmental problems associated with the uncontrolled discharge of the
 residual effluents into water courses, which is of great benefit to
 industry. In addition, this provides the advantageous reusage of a
 polluting sub-product generated in manufacturing alcohol through
 fermenting concentrates.
 By applying the process of this invention, the contamination from
 distilleries is prevented, which helps them to comply with the
 environmental standards actually in force, wherein a main objective is
 stated as the recovery of any type of resources present in residues.
 Another benefit, which arises from this process, is to make the distillery
 more competitive by gaining additional economic resources in place of
 having to pay for destroying such residues.
 DETAILED DESCRIPTION OF THE INVENTION
 The process is initiated by separating precipitates which are obtained by
 introducing the effluent which is at a minimum temperature of 80.degree.
 C. into a designed tank wherein settling occurs.
 Effluent volume determines tank size. Also, precipitate extraction can be
 carried out using nozzle type centrifugation machines or by other means.
 After extracting the precipitates, the liquid effluent having an average
 solid concentration degree of up to 16% (between active matter and
 non-settled insoluble matter) is sent to a concentration plant. The
 effluent is heated up to 80.degree. C. at the concentration plant inlet.
 Concentration can be carried out in one or two steps, according to the
 usage to be given to the final product.
 When the effluent is submitted to only a one step concentration, a
 concentration plant is used which receives effluent at a concentration
 from 4% to 16% weight/weight and delivers it at a concentration from 45%
 to 52% weight/weight. Insoluble solids contained in the effluent prior to
 concentration at a level of 2%, if not eliminated and remain during the
 concentration process may reach a 12% concentration, weight/weight in the
 concentrated effluent.
 Depending on the type of raw material, which the distillery uses, and the
 type of concentrator and with a view to water-reducers or fluidizers,
 dispersants, tensoactives and agglutinants, a 3% rate of polymeric complex
 can be produced as gels and/or colloids.
 These high insoluble content concentrations are sent to those industrial
 application fields wherein such insoluble matter does not show rejection
 problems as for example, agglomerated wood panel manufacturing, dispersant
 fluidizers in carrying limestone through pipe lines.
 When concentration is carried out in two steps, the first step concentrates
 the effluent up to a concentration which can range between 32% and 45%
 weight/weight and in a concentrator chamber at this first step, this is
 carried out at a 60.degree. C. temperature if a change of the dominant
 cation is desired. For this purpose, in the above mentioned concentration
 chamber, a compound is dosed which reacts with the effluent and exchanges
 its cation with the effluent, producing a change in the pH level of the
 effluent or polymeric complex. If the pH value reaches up to 9.0, colloids
 or gels, if any are present, re-dissolve and the risk of fermentation is
 reduced.
 At this stage, the effluent volume has been reduced to approximately a
 quarter of its prior volume, as water condensates or as water, which
 corresponds to 750 liters per 1000 liters of processed effluent.
 The semi-concentrated effluent is submitted to a settling process which
 lasts from 8 to 24 hours (depending on the settling tank volume) in order
 to complete all chemical reactions and flocculations through naturally
 occurring processes or through chemical or biological methods. Later, a
 process of eliminating insoluble matter and precipitates which were
 produced during the evaporating and settling process is carried out, as
 described above.
 During the settling process and if the pH has not been previously
 increased, it is possible to add certain compounds, particularly enzymes
 which react with the polymeric complex which is in a gel or colloid state,
 and which convert it back to a dissolved becoming solid state.
 The settled effluent or polymeric complex, or the phase containing the
 active compound is sent to a centrifugating clearing station wherein
 suspended solids are separated. The effluent leaves this clearing process
 or process for eliminating insoluble matter with a non-diluted solid
 content of about 0.1% and at a temperature of around 30.degree. C.
 Extracted muds, which are supposed to be at around 2% or 3% of the initial
 effluent volume, are extracted from the centrifuge pushed by a water flow
 in order to regulate its humidity up to a 25% range. Cleared effluent is
 passed through a heat exchanger and the temperature is increased to
 60.degree. C. taking it to a second concentration step wherein it is
 submitted to a concentration of around 52% weight/weight. It can also be
 concentrated by other means provided that the temperature is below
 92.degree. C., except when it is necessary to obtain the final product as
 a gel. In such a case, the concentration temperature must be above
 92.degree. C.
 The polymeric complex thus obtained and free from insoluble matter
 represents a percentage of around a 14% of the initial effluent, is an
 excellent water-reducer or fluidizer, dispersant, tensio-active, adhesive
 and agluttinant product and is sent to those industries which need this
 product well cleared, that is, concrete and mortar additive, agrochemical
 fungicide, pesticide, ceramic and refractory, dye and paint industries, as
 well as other applications.
 In the case when a gel-free or colloid-free product is required, it is
 necessary to take extreme care in controlling temperature and vacuum. For
 a good development process, the temperature cannot rise above 92.degree.
 C., the most advisable temperature ranging from 22 to 84.degree. C.
 Depression should be, according to the process point, between
 2.5.times.10.sup.4 Pascal to 9.times.10.sup.4 Pascal (Pa).
 Concentration stations can use any of the existing concentration systems as
 whether evaporation systems or another type, provided that they have
 temperature and vacuum control systems in order to keep the aforementioned
 parameters. Another way to separate the active matter from the excess
 water is to initiate using flocculants, which help in phase separation,
 wherein one of the phases contains the excess water and the other phase
 contains the precipitate having the active principle. Flocculants can be
 chemical or biological.
 Changing the dominant cation is achieved by ionic exchange during
 concentration at any of its steps.
 Clearing or separation of insoluble matter is carried out by settling or
 through centrifugation or using both techniques in the same process and
 according to the clearing degree required. Although we have described
 concentration in two steps wherein clearing is carried out in the stage
 from the first step to the second step, in practice, it is possible to
 achieve clearing through different methods as follows:
 To clear before introducing the effluent into the concentrator, having the
 effluent at a concentration level from 4% to 15% using a settling or
 clearing tank and introducing additives such as sodium hydroxide,
 phosphoric acid and other compounds which may have the same effect in
 order to precipitate sulphates and other insoluble matter. At the end of
 the process, it is possible to obtain less than 2.5% of insoluble matter.
 The settling tank can be in-line with the process and consequently it is
 important to adequately design the capacity and shape of the tank so that
 effluent residing time is precise and settling of insoluble matter occurs.
 The settling tank can be separated from the process and in that case
 several tanks are required, so that when some of them are settling, others
 containing the settled effluent are sending the liquid to the
 concentrator;
 Clearing by way of disc type centrifuge machines, when the effluent has a
 concentration of between 32% and 45%, that is, between the first and
 second clearing steps. Thus, 0.1% of insoluble matter is obtained at the
 centrifuge machine outlet.
 Clearing the effluent after concentrating and when this effluent has a
 concentration of between 45% and 52%, and using gravity-tanks. For
 settling, these tanks are constructed with a tapered bottom as well as
 with sample takers at several heights in order to continuously check the
 insoluble matter concentration and the settling state. Using this type of
 clearing it is possible to obtain a percentage of insoluble matter less
 than 1.5 according to settling time. This clearing method requires many
 tanks of great volumes and consequently it is not recommended.
 Carrying out clearing by using (both of the above-described methods) in the
 same process.
 The quality of the effluent should determine what type of separation is to
 be used. Precipitates are measured through centrifugation using a lab
 centrifuge and an adequate graded test tube. In practice and for
 concentrations over 45%, the effluent is dissolved in water up to 50% by
 weight and centrifuged at 3000 rpm for 5 minutes, wherein the insoluble
 content settles at the bottom of test tube and this is multiplied by two
 to compensate for the aforementioned dissolving effect. For concentrations
 below 45%, precipitates are centrifuged without dissolving.
 Insoluble matter analysis also indicates the existence or not of portions
 of polymeric complex, shaped as gel and/or colloid. To convert these gels
 or colloids to their previous polymeric complex state as dissolved solids,
 acidity is raised to a pH of about 9 or suitable enzymes are added at a
 suitable rate for at least 15 minutes and heated at 50.degree. C. at the
 appropriate site of the plant.
 Using the effluent, which has been concentrated and cleared or not, such,
 obtained through the above disclosed processes such as settling,
 centrifugation, concentration or any other procedure of phase separation,
 i.e., in a liquid state, as water reducer or fluidizer, dispersant,
 tensio-active, adhesive or agglutinant, it is necessary to have a suitable
 installation for handling and storage of great volumes which is expensive
 but feasible when dealing with transport over medium or short distances.
 When necessary to transport it over long distances or to store and
 distribute in small quantities it is better to convert the liquid into
 powder and pack in bags.
 For this purpose, the concentrated effluent is submitted to a drying
 operation and dispersants, tensio-actives, agglutinants and adhesives are
 obtained in a powder form with a residual humidity of below 5% in weight.
 Drying is carried out mainly at Drying Plants through spraying or powdering
 and through hot air at temperatures between 300.degree. C. and 900.degree.
 C.
 Since the powder obtained is hygroscopic, handling requires necessary
 precautions in order to avoid air contact and it must be packed into bags
 which have suitable seals.
 The process outlined by this invention offers numerous advantages when
 compared to the current existing processes since:
 it is based on a by-product, which has not been used so far, and it
 represents a serious environmental threat;
 it is a very simple process which requires few steps and which consequently
 reduces cost and increases performance of the whole process;
 it is a modular process which makes it possible to obtain polymeric complex
 either in an aqueous solution at the desired concentration and with a
 degree of insoluble matter allowed according to application or in powder
 form, which facilitates and cuts costs of transport and storage;
 the water reducers, fluidizers, dispersants, tensio-actives and
 agglutinants (solution or powder) obtained according to the process of the
 invention show a high homogeneity due to the fact that the raw material is
 always the same or very similar which facilitates industrial usage since
 it makes it easier to prepare formulations as required.

EXAMPLES
 Some examples of dispersant, tensio-active, agglutinant and adhesive agents
 obtained according to the above process during development and research
 are outlined below:
 Example A
 The production process and the related research were carried out at a
 distillery, which produces ethanol from sugar mill molasses. Distillery
 production was 30,000 liters of ethanol a day and an effluent production
 of 15,000 per hour with a 91.5% water content weight, 7% of polymeric
 complex and 1.5% of insoluble matter which mainly comprises calcium
 sulphate and an distillation tower outlet temperature of 80%.
 Precipitates were separated through centrifugation at a nozzle centrifuge.
 A four-chamber concentrator comprised of descending columns and a snap or
 abrupt expansion chamber was used.
 The steam entering the first descending column chamber was at 120.degree.
 C. and condensates at the fourth chamber outlet were at 75.degree. C. The
 abrupt expansion effect was provided by way of a separate circuit using
 the same steam.
 A polymeric complex was produced at the concentration installation outlet
 with a 44% weight concentration, a 10% insoluble matter and water at a
 rate of 44%, a temperature of 82.degree. C. and a volume of flow of 2,145
 liters/hour.
 The concentrated effluent contained gels and was settled by gravity over
 five days and a polymeric complex was obtained having an insoluble matter
 percentage of less than 2.5. The polymeric complex was sold to industry.
 Example B
 This process took place in an ethanol-producing distillery using molasses
 from sugar factories, which produces 50,000 liters/day of alcohol and
 25,000 liters/hour of effluent, where the effluent was concentrated in a
 Concentration Plant which comprises a four descending chambers and two
 abrupt expansion chambers. Effluent entering the concentrator had an 8%
 polymeric complex concentration, a 1% insoluble matter content and 91%
 water content.
 The pressure of the steam supply to the concentration device was regulated
 and water at 80.degree. C. was added which decreased steam supply
 temperature to 92.degree. C.
 Insoluble matter at the concentrator outlet was 6%, consisting of being
 polymeric complex concentration about 50% and water concentration about
 44%.
 The polymeric complex, which contained no gels, was settled over five days
 and the insoluble matter concentration was less than 1.5%.
 This trial showed that the steam supply temperature regulate both gels and
 insoluble content since from a certain value it precipitated calcium
 sulphate, which remained in a dissolved state.
 Several tests were carried out and it was verified that the best operating
 point having the least insoluble matter precipitation was at a heating
 fluid temperature for vaporization below 84.degree. C.
 Example C
 At the same distillery a centrifuging clearing plant was used between the
 outlet of first abrupt expansion effect and second-effect or
 outlet-effect. The polymeric complex was centrifuged and the percentage of
 insoluble matter was determined.
 It was less than 0.1% at the centrifugal machine outlet. The effluent was
 heated at 60.degree. C. before introducing it to the second abrupt
 expansion effect, concentration ended and a 0.2% level of insoluble matter
 was obtained from the concentrated effluent or polymeric complex but after
 a 24 hour settling period this insoluble matter increased to a level of
 0.6%. This test showed that a 24-hour settling period is necessary before
 centrifuging the polymeric complex in order to obtain the whole insoluble
 matter therein.
 Example D
 At the same distillery the same test was repeated but leaving the polymeric
 complex, which was produced from the first abrupt expansion effect at a
 40% concentration, to settle for a 24-hour period. This product was then
 centrifuged to obtain 0.1% of insoluble matter, heated at
 60.quadrature.0.quadrature.C and the final concentration was carried out
 at the second effect outlet.
 The amount of 0.15% of insoluble matter was obtained at the second effect
 outlet and after a 24 hour period the insoluble content rose to 0.3% and
 stayed at this level.
 Example E
 It was noted at the same distillery that upon repeating the tests from
 Example D and after analyzing the insoluble matter, a layer of gelled (in
 the shape of gel) polymeric complex appeared at the bottom of the test
 tube at a rate of 1% and a second layer from this complex as colloid at a
 rate of 2%.
 Suitable enzymes were added to the concentrated polymeric complex at the
 outlet of the first abrupt expansion effect and also the to settling tank
 before centrifuging at a rate of 50 PPM. This composition was centrifuged
 and concentration ended. It was shown after analyzing, that the colloids
 and gels disappeared and the tests on the effectiveness of the polymer
 complex demonstrated that its effectiveness as dispersant, tensio-active,
 agluttinant or adhesive did not decrease.
 Example F
 The test from Example F was repeated with the aim of changing the dominant
 cation in the polymeric complex, which was calcium at a rate of 3%. A
 sodium based chemical compound was added in a controlled manner at the
 first abrupt expansion effect site. The pH of the complex increased also
 in a controlled manner and the sodium cation became dominant at a valve of
 2.8%; calcium cation decreased to a value of 1%.
 It was noted that the gels and colloids disappeared when the pH increased
 to a value of 9.
 Example G
 The polymeric complex from the above Example D was dried in a Drying Plant
 using a spray dryer at a production rate of 1,000 kg/hour. A powder, which
 displayed a residual humidity of 3.5%, was obtained.
 This product was packed into three-ply paper bags, wherein one of them was
 polyvinyl-covered. After a month, it retained its residual humidity and
 maintained its characteristics as when packed.
 The powder was water-dissolved to obtain the same concentration as before
 drying and the polymer solution thus obtained integrally reproduced all
 the characteristics it displayed when dried.