Multi-stage desolventizing of oleaginous materials extracted with alcoholic solvents

Abstract

Systems and techniques may be used to extract solid materials with alcohol-based solvents. For subsequent recovery of the solvent after extraction, the solid material that has been wetted by the solvent that has undergone extraction may be desolventized. The solvent-wetted solid material may be desolventized in a single vessel or in a plurality of different vessels in multiple stages to produce multiple corresponding condensate streams containing alcohol and water evaporated from the solvent-wetted solid material. By dividing the desolventizing into multiple stages, the composition of these condensate streams produced during the desolventizing can be individually controlled to benefit downstream processing. For example, a first condensate stream generated during desolvation may have a relatively low amount of water, while a second condensate stream generated during desolvation may have a relatively high amount of water. The first condensate stream may be recycled back to the extractor without further removal of water, while the second condensate stream may be subjected to additional treatment to remove water.

Description

[0001] Related Applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 400,748, filed on August 24, 2022, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to solvent extraction, and more particularly to liquid-solvent extraction using alcohol-based solvents. Background Art

[0004] Many different industries use extractors to extract and recycle liquid materials entrained in solids. For example, producers of oils from renewable organic sources use extractors to extract oil from oily materials such as soybeans, rapeseed, sunflower seeds, peanuts, cottonseed, palm kernels, and corn germ. The oily material is contacted with an organic solvent in the extractor, causing the oil to be extracted from the surrounding cell structure into the organic solvent. As another example, extractors are used to recover oil from oil sands and other oil-rich materials. Typically, the oil-rich material is ground into small particles, which are then passed through an extractor to extract the oil from the solid material into the surrounding organic solvent.

[0005] During operation, the selected feedstock is passed through an extractor and contacted with a solvent. The solvent can extract oil from the feedstock to produce an oil-depleted solid effluent and a mixed oil stream. The mixed oil stream can contain the solvent used for extraction and the oil extracted from the feedstock.

[0006] In implementation, solvents such as hexane are generally used to extract oil from oily materials. The oil and / or the solid extracted can be used as an intermediate or final product consumed by humans and / or animals. Although solvents are removed from the oil and / or the solid extracted before consumption, consumers are increasingly sensitive to food production processes and standards. Ethanol is an alternative solvent to hexane, which can be used to separate oil from various oily materials. Ethanol is GRAS (generally recognized as safe), can be produced in an organic manner, including by renewable raw materials, and has been accepted by the consumer public as a component of alcoholic beverages. Summary of the invention

[0007] Generally speaking, the present disclosure relates to devices, systems and techniques for treating oil-containing materials with alcohol-based solvents to extract oil from the material. In some examples, the system includes an extractor configured to process an oil-containing raw material. The extractor receives the oil-containing raw material and transports the material from an inlet to an outlet through the extractor. The extractor also receives an alcohol-based solvent at a solvent inlet and transports the solvent to a solvent outlet through the extractor. The alcohol-based solvent can travel through the extractor in a countercurrent direction from the material travel direction of the raw material through the extractor. In either case, when the raw material moves from the inlet to the outlet through the extractor, the concentration of oil in the raw material can be reduced. Similarly, when the solvent moves from the solvent inlet to the solvent outlet through the extractor, the concentration of oil in the solvent can be increased.

[0008] The solid material that has undergone extraction can be discharged from the outlet of the extractor for further downstream processing. The solid material is usually solvent-wetted and carries residual solvent with the extracted solid material. Therefore, the extracted solid material containing solvent can be dried to recover the residual solvent for reuse and / or provide dried extracted solid material for further disposal. The residual solvent carried by the extracted solid material can include alcohol (e.g., ethanol) and water for extracting oil from the solid material in the extractor. The water in the residual solvent carried by the extracted solid material can be water introduced into the extractor together with the fresh solvent and / or water carried with the fresh solid material introduced into the extractor.

[0009] The solvent-wet solid material discharged from the extractor can be desolventized to dry the extracted solid material for further use and recover the residual solvent for recycling and / or reuse. For example, the solvent-wet solid material can be heated to evaporate the solvent carried by the extracted solid material, thereby separating the solvent from the extracted solid material. The evaporated solvent can be condensed into a liquid for recovery and reuse.

[0010] In practice, the condensed solvent recovered by desolventizing the solvent-wetted solid material may contain excess water, which requires separation of the water from the alcohol in the solvent before the alcohol and / or solvent can be reused in the extraction process. However, when certain alcohols such as ethanol are used, an azeotropic mixture is formed between the alcohol and water in the solvent. This makes it difficult to separate the excess water from the alcohol and limits the effective recovery of the alcohol for reuse in the extraction process.

[0011] According to some examples of the present disclosure, systems and techniques for recovering alcohol from a solvent-wetted solid material that has undergone extraction using multi-stage desolventizing are described. For example, the solvent-wetted solid material discharged from the extractor can be desolventized in multiple stages in a single container or in multiple different containers to produce multiple corresponding vapor streams, which are then condensed into recovered condensate streams. Each condensate stream can contain alcohol and water evaporated from the solvent-wetted solid material. The composition of the condensate stream produced during desolventizing can be individually controlled to facilitate downstream processing. Compared with desolventizing the solvent-wetted solid material and producing a single condensate stream for further processing, this can allow more efficient and effective recovery of alcohol for reuse in the extraction process.

[0012] For example, the applicant has recognized that when evaporating and condensing solvent from a solvent-wetted extracted solid material, the composition of the condensate can change as the solvent-wetted extracted solid material dries from solvent-wet to relatively dry. In some implementations, the concentration of water in the condensate produced by drying the solvent-wetted extracted solid material may be relatively low when the solvent-wetted solid material is initially dried, but may increase as the solvent-wetted extracted solid material is further dried. For example, the concentration of water in the condensate produced by heating the solvent-wetted solid material may be relatively low during the initial drying (e.g., 2 wt % to 3 wt % water), but may increase as the solvent-wetted solid material is further dried (e.g., 4 wt % to 6 wt % water). For example, the concentration of water in the condensate produced when drying the solvent-wetted solid material may be at a relatively low level until the solvent-wetted solid material reaches a threshold dryness level (e.g., an alcohol level), at which time the concentration of water in the condensate may quickly increase to a relatively higher level.

[0013] According to some specific implementations of the present disclosure, systems and techniques for desolventizing a solvent-wetted extraction material are described, which involve producing a plurality of different condensate streams each having different concentrations of alcohol and water. For example, the solvent-wetted extraction material can be heated to produce a first vapor stream, which is then condensed to provide a first condensate having a first concentration of water. The solvent-wetted extraction material can be further heated to produce a second vapor stream, which is then condensed to provide a second condensate stream having a second concentration of water greater than the first concentration of water in the first condensate.

[0014] In some applications, the concentration of alcohol in the first condensate can be high enough (and the first concentration of water low enough) that the first condensate can be recycled back to the extractor and reintroduced into the extractor without further processing to remove water from the first condensate. The second condensate can be further processed to reduce the amount of water in the condensate, for example to a level suitable for recycling the stream back to the extractor. Since the second condensate necessarily has a lower volume than the combination of the first condensate and the second condensate together, the energy and processing requirements to reduce the water in the second condensate can be reduced compared to producing a single condensate of a larger volume that needs to be processed.

[0015] In one example, a method is described that includes extracting a material to be processed with a solvent comprising an alcohol in an extractor to produce an extracted material stream and a mixed oil stream. The extracted material stream comprises extracted solid material wetted with a liquid comprising alcohol and water. The method involves desolventizing the extracted material stream to a first alcohol level, thereby producing a partially desolventized extracted material and a first condensate, wherein the first condensate comprises water and alcohol. The method further involves desolventizing the partially desolventized extracted material to a second alcohol level that is lower than the first alcohol level, thereby producing a desolventized extracted material and a second condensate. The example provides that the second condensate comprises water and alcohol, and the weight fraction of water in the second condensate is greater than the weight fraction of water in the first condensate.

[0016] The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a block diagram illustrating an exemplary extraction system according to the present disclosure, the system including multi-stage desolventization performed in multiple vessels.

[0018] Figure 2 is a block diagram illustrating another exemplary extraction system according to the present disclosure, the system including multi-stage desolventization performed in a single vessel.

[0019] Figure 3 Yes, you can Figure 1 and Figure 2 Illustration of an exemplary extractor configuration used in an exemplary system of FIG.

[0020] Figure 4 is a plot of experimental desolvation water concentration data. DETAILED DESCRIPTION

[0021] Generally speaking, the present disclosure relates to a liquid-solid extractor system and method capable of extracting one or more desired products from a flow of solid material. In some examples, the solid material is processed in a continuous flow extractor that delivers a continuous flow of the material from its inlet to its outlet while delivering the solvent from the solvent inlet to the solvent outlet in a countercurrent direction. When the solvent is delivered from its inlet to its outlet, the concentration of the extracted liquid relative to the solvent increases from a relatively small extract to solvent ratio to a relatively large extract to solvent ratio. Similarly, when the solid material is delivered in the opposite direction, the concentration of the extract in the solid raw material decreases from a relatively high concentration at the inlet to a relatively low concentration at the outlet. The amount of time (also referred to as the residence time) that the solid material remains in contact with the solvent in the extractor can vary, for example, depending on the material being processed and the operating characteristics of the extractor, although it will typically be in the range of 15 minutes to 3 hours, such as 1 hour to 2 hours.

[0022] The solvent (which may be referred to as mixed oil) discharged from the extractor contains components (e.g., oil, carbohydrates, sugars) extracted from the solid raw material. The solvent-wetted solid material discharged from the extractor may be a residual solid raw material that has undergone extraction. In some configurations according to the present disclosure, systems and techniques for desolventizing the solvent-wetted solid material discharged from the extractor are described. For example, the solvent-wetted solid material may be desolventized in a single container or in a plurality of different containers in multiple stages to produce a plurality of corresponding condensate streams containing alcohol and water evaporated from the solvent-wetted solid material. By dividing the desolventizing into multiple stages, the composition of the condensate stream produced during the desolventizing can be individually controlled to benefit downstream processing. For example, the first condensate stream produced during the desolventizing can have a relatively low amount of water, while the second condensate stream produced during the desolventizing can have a relatively high amount of water. The first condensate stream may be recycled back to the extractor without further removing water, while the second condensate stream may undergo additional treatment to remove water.

[0023] Figure 11 is a block diagram illustrating an exemplary extraction system 10 according to the present disclosure. The system 10 includes an extractor 12 and at least one desolventizing unit, which is shown as being implemented using a first desolventizing unit 14 and a second desolventizing unit 16 downstream of the first desolventizing unit. The system 10 is also shown as including an optional dryer 18 upstream of the extractor 12. The extractor 12 has a feed inlet 20 that can receive solid material after undergoing drying in the optional dryer 18 for extraction within the extractor. The extractor 12 also has a feed outlet 22 that can discharge the solid particulate material after it has undergone extraction and has a lower extract concentration than the fresh incoming material. The extractor 12 also has a solvent inlet 24 configured to introduce fresh solvent into the extractor and a solvent outlet 26 configured to discharge a mixed oil formed by extracting extractable components from the solid material.

[0024] In operation, the solid material being processed is contacted with a solvent within the extractor 12 (e.g., in a co-current or counter-current manner) so that components soluble in the solvent are extracted from the solid material into the solvent. The extractor 12 may use any suitable extraction fluid to process any desired solid material. Exemplary types of solid materials that may be processed using the extractor 12 include, but are not limited to, oily substances such as soybeans, rapeseed, sunflower seeds, peanuts, cottonseed, palm kernels, and corn germ; oil seeds and fruits; bituminous materials (e.g., bituminous roofing sheets including aggregates such as crushed mineral rock, asphalt, and fiber-reinforced materials); alfalfa; almond shells; anchovy meal; bark; coffee beans and / or coffee grounds, carrots; chicken parts; diatomic pellets; fish meal; hops; oats; pine needles; tar sands; vanilla; and wood chips and / or pulp.

[0025] The alcohol-based solvents that can be used to extract from the solid material include, but are not limited to, monohydroxy or polyhydroxy (e.g., dihydroxy) alcohols having a carbon chain length of 1 to 8 carbons (e.g., 1 to 4 carbons or 2 to 3 carbons). For example, the alcohol-based solvent can be ethanol or isopropanol. In some examples, the alcohol-based solvent is substantially composed of alcohol (e.g., containing or not containing water). For example, the alcohol-based solvent can be an aqueous alcohol or anhydrous alcohol solvent. In some examples, the alcohol-based solvent supplied to the solvent inlet 24 of the extractor 12 has an alcohol content greater than 90% by weight and a water content less than 10% by weight, such as an alcohol content greater than 95% by weight and a water content less than 5% by weight, or an alcohol content greater than 98% by weight and a water content less than 5% by weight. In some examples, the solvent includes alcohol and water, which forms an azeotropic mixture of alcohol and water having the same concentration in the liquid phase and the gas phase, thereby preventing separation by distillation.

[0026] In some implementations, the solid material supplied to the extractor 12 is dried by a dryer 18 prior to extraction in the extractor 12. The dryer 18 can reduce the amount of water in the solid material supplied to the extractor 12. When an alcohol-based solvent is used, the water content of the solid material introduced into the extractor can be controlled to prevent excessive water from entering the extractor, which could dilute the solvent (e.g., reducing the effectiveness of the extraction and / or making solvent recovery challenging).

[0027] exist Figure 1 In the example of , the extraction system 10 includes a dryer 18 to dry the solid feed material before the material is introduced into the extractor 12. The dryer 18 can dry the material before and / or after size reduction and / or after other pretreatment (when performed) and in different specific implementations, the dryer 18 can be an indirect dryer and / or a direct dryer. For example, the dryer 18 can indirectly dry the solid material, such as by passing a heat transfer fluid through a jacketed drying vessel. Additionally or alternatively, the dryer 18 can directly dry the solid material, such as by introducing a hot gas (e.g., dry air, nitrogen) into the solid material to absorb moisture and then exhaust the gas out of the vessel.

[0028] Generally speaking, the dryer 18 can dry the solid material at a temperature that effectively evaporates at least a portion of the moisture present in the material, but can also dry the solid material at a temperature that is not hot enough to damage the solid material (e.g., change the structure of the material and / or reduce the nutritional properties of the material). In some specific implementations, the dryer 18 dries the solid material at a temperature greater than 30°C, such as greater than 50°C, or greater than 60°C, greater than 70°C, greater than 80°C, or greater than 100°C. Additionally or alternatively, the dryer 18 can dry the solid material at a temperature less than 125°C, such as less than 100°C or less than 80°C. For example, the dryer 18 can dry the solid material at a temperature below the boiling point of water. In some examples, the dryer 18 can dry the solid material at a temperature in the range of 40°C to 90°C, such as 50°C to 80°C. The dryer 18 can generally operate at atmospheric pressure, but in other examples, it can be configured to operate at non-atmospheric pressure (e.g., vacuum pressure, positive pressure).

[0029] When used, the dryer 18 can reduce the moisture content of the solid material. In some examples, the dryer 18 is configured to dry the solid material to be processed to a moisture content of 5 wt % or less, such as 3 wt % or less, or 2 wt % or less. Depending on the moisture content of the incoming solid material, the dryer 18 can reduce the moisture content of the solid material by at least 0.5 wt %, such as at least one wt %, at least two wt %, at least three wt %, at least four wt %, or at least five wt %.

[0030] The extractor 12 can produce a solvent-wetted solid stream discharged through the feed outlet 22 and a mixed oil stream discharged through the solvent outlet 26. The mixed oil stream can be further processed to separate the solvent from the oil. Exemplary systems and techniques for separating the solvent from the oil in the mixed oil stream are described in PCT patent application No. PCT / US22 / 17965, entitled "Alcohol Solvent Recovery for Oily Material Extraction", filed on February 25, 2022, and PCT publication No. WO 2022 / 006165, entitled "Oleaginous Material Extraction Using Alcohol Solvent", filed on June 29, 2021, and the entire contents of the PCT patent application and the PCT publication are incorporated herein by reference.

[0031] In order to recover the solvent from the solvent-wetted extracted solid stream and further prepare the residual extracted solid material for final use, the solvent-wetted extracted solid stream can be desolventized by heating the solvent-wetted extracted solid stream to evaporate the solvent from the extracted solid stream. The vapor generated by heating the solvent-wetted extracted solid stream can then be condensed to produce a liquid containing alcohol and water recovered from the solvent-wetted extracted solid stream. According to some specific implementations of the present application, the solvent-wetted extracted solid stream can be desolventized to produce multiple different condensate streams each having different concentrations of water and alcohol. This can allow different downstream processing and use of the resulting condensate stream in the extraction system 10.

[0032] exist Figure 1 In the example of FIG. 1 , the extraction system 10 is shown as being implemented with a first desolventizer unit 14 and a second desolventizer unit 16 downstream of the first desolventizer. In various applications, the extraction system 10 can utilize a single desolventizer unit (e.g., as combined with Figure 2 ) or a greater number of desolventizer units (e.g., three, four, or more) without departing from the scope of the present disclosure. Figure 1 In the example of FIG. 1 , solvent-wetted extracted solid material (also referred to as “extracted solid material”) that has been extracted in extractor 12 is discharged from feed outlet 22 of extractor 12. The extracted material can be received by first desolventizer unit 14 and desolventized to a first alcohol level, thereby producing partially desolventized extracted material 28 and a first vapor stream that is condensed in first condenser 14C to provide first condensate 30.

[0033] exist Figure 1, partially desolventized extracted material 28 may be discharged from the first desolventizer unit 14 and received by the second desolventizer unit 16. The second desolventizer unit 16 may desolventize the partially desolventized extracted material 28 to a second alcohol level that is lower than the first alcohol level, thereby producing a desolventized extracted material 32 and a second vapor stream that is condensed in the second condenser 16C to provide a second condensate 34. The first condensate 30 and the second condensate 34 may each contain water and alcohol recovered from the solvent-wet extracted solid material, wherein the concentration of water is greater in the second condensate 34 than in the first condensate 30. That is, the weight fraction of water in the second condensate may be greater than the weight fraction of water in the first condensate.

[0034] In implementations, the incoming solvent-wetted extracted solid material supplied from the extractor 12 to the first desolventizer unit 14 may be greater than 20 wt% solvent (e.g., alcohol and water) based on the total weight of the solvent-wetted extracted solid material (e.g., the combined weight of the extracted solid material and the weight of the liquid that wets the solid material). For example, the concentration of solvent in the incoming solvent-wetted extracted solid material may be greater than 25 wt%, such as greater than 30 wt%, greater than 35 wt%, or greater than 45 wt%, based on the total weight of the solvent-wetted extracted solid material. In some applications, the concentration of solvent in the incoming solvent-wetted solid material supplied to the first desolventizer unit 14 may be in the range of 15 wt% to 50 wt%, such as 30 wt% to 50 wt% or 35 wt% to 45 wt%, based on the total weight of the solvent-wetted solid material. The concentration of the solvent that wets the extracted solid material may be within any of the ranges discussed above with respect to exemplary alcohol-based solvent concentrations. In some implementations, the solvent-wet extracted solid material from extractor 12 can undergo one or more initial steps of thermal desolventization and / or mechanical desolventization before being received by first desolventization unit 14 for further desolventization.

[0035] The first desolventizing unit 14 can receive the solvent-wet extracted solid material and evaporate a portion of the solvent from the extracted solid material, thereby reducing the concentration of alcohol (and water) in the extracted solid material to a first alcohol level, which can also be referred to as a first alcohol concentration. This can produce a partially desolventized extracted material 28 having a first alcohol level, which is discharged from the first desolventizing unit 14 for further processing. For example, the first desolventizing unit 14 can evaporate an amount of alcohol from the incoming solvent-wet extracted solid material received (directly or indirectly) from the extractor 12, thereby effectively producing a partially desolventized extracted material 28 having a first alcohol level, the first alcohol level being less than 20% by weight, such as less than 15% by weight, less than 12% by weight, less than 10% by weight, less than 8% by weight, or less than 6% by weight, based on the total weight of the partially desolventized extracted material.

[0036] Although the first desolventizing unit 14 can evaporate a portion of the alcohol from the incoming solvent-wet extracted solid material received from the extractor 12, the amount of alcohol removed from the solvent-wet extracted solid material in the first desolventizing unit 14 can be limited to prevent excess water from being entrained with the evaporated alcohol into the first condensate 30. For example, the first desolventizing unit 14 can evaporate an amount of alcohol from the incoming solvent-wet extracted solid material effective to produce the partially desolventized extracted material 28 having a first alcohol level greater than 3 wt %, such as greater than 4 wt %, greater than 5 wt %, or greater than 6 wt %, based on the total weight of the partially desolventized extracted material. For example, the first desolventizing unit 14 can evaporate an amount of alcohol from the incoming solvent-wet extracted solid material effective to produce the partially desolventized extracted material 28 having a first alcohol level in the range of 5 wt % to 15 wt %, such as 5 wt % to 10 wt %, based on the total weight of the partially desolventized extracted material. The amount of alcohol evaporated from the solvent-wet extracted solid material supplied to the first desolventizing unit 14 can be controlled, for example, by controlling the size and residence time of the material being processed in the first desolventizing unit 14 and / or the operating temperature and / or pressure inside the unit.

[0037] The solvent evaporated from the solvent-wet extracted solid material in the first desolventizing unit 14 to produce the partially desolventized extracted material 28 can be condensed in a condenser 14C operably connected to the first desolventizing unit. This can produce a first condensate stream 30, which can be a complete condensate of the vapor produced by the first desolventizing unit 14 or a partial condensate of the vapor produced by the unit (e.g., providing a mixed vapor-liquid phase). By controlling the extent to which the solvent-wet extracted solid material is desolventized in the first desolventizing unit 14, the composition of the first condensate 30 can be controlled. In particular, the relative amounts of water and alcohol in the first condensate 30 can be controlled to provide a condensate containing a relatively limited amount of water.

[0038] In various applications, the concentration of alcohol in the first condensate 30 is at least 90% alcohol by weight, such as greater than 92% alcohol, greater than 94% alcohol, greater than 95% alcohol, greater than 96% alcohol, greater than 97% alcohol, greater than 97.5% alcohol, greater than 98% alcohol, greater than 98.5% alcohol, or greater than 99% alcohol by weight, based on the total weight of the condensate (e.g., including the combined weight of the alcohol and water that formed the condensate). The remainder of the weight of the first condensate 30 may be substantially or entirely water evaporated from the solvent-wet extracted solid material along with the alcohol. Thus, the weight fraction of water in the first condensate 30 (which may be reported as a percentage) may be less than 8 wt % water, such as less than 6 wt % water, less than 5 wt % water, less than 4 wt % water, less than 3 wt % water, less than 2.5 wt % water, less than 2 wt % water, less than 1.5 wt % water, or less than 1 wt % water, based on the total weight of the condensate (e.g., including the combined weight of the alcohol and water that form the condensate). For example, the first condensate 30 may have a concentration of greater than 90 wt % alcohol and less than 10 wt % water, such as greater than 95 wt % alcohol and less than 5 wt % water, or greater than 98 wt % alcohol and less than 2 wt % water, based on the total weight of the condensate.

[0039] exist Figure 1 In the example of , the second desolventizing unit 16 receives the partially desolventized extracted material 28 that was initially desolventized in the first desolventizing unit 14, which carries residual solvent (e.g., alcohol and water). The second desolventizing unit 16 can receive the partially desolventized extracted material 28 and evaporate a portion of the remaining solvent from the partially desolventized extracted material, thereby reducing the concentration of alcohol (and water) in the partially desolventized extracted solid material to a second alcohol level, which can also be referred to as a second alcohol concentration. This can produce a desolventized extracted material 32 having a second alcohol level, which is discharged from the second desolventizing unit 16 for further processing or disposal. It should be understood that reference to a dried and / or desolventized solid material refers to a material that is relatively dry and desolventized and does not need to be completely dried or desolventized, or the material is free of solvent.

[0040] For example, the second desolventizing unit 16 can evaporate an amount of alcohol from the partially desolventized extracted material 28, thereby effectively producing a desolventized extracted material 32 having a second alcohol level that is less than 15% by weight, such as less than 10% by weight, less than 8% by weight, less than 5% by weight, less than 3% by weight, less than 2% by weight, or less than 1% by weight, based on the total weight of the desolventized extracted material (e.g., the combined weight of the extracted solid material and the weight of the remaining liquid that wets the solid material). For example, the second desolventizing unit 16 can evaporate an amount of alcohol from the partially desolventized extracted material 28, thereby effectively producing a desolventized extracted material 32 having a second alcohol level of 0.5% by weight (5000 ppm), such as less than 0.1% by weight (1000 ppm). In general, the partially desolventized extracted material 28 can be desolventized to a level suitable for the intended subsequent use and / or disposal of the resulting desolventized extracted material 32. The amount of alcohol evaporated from the partially desolventized extracted material 28 may be controlled, for example, by controlling the size and residence time of the material being processed in the second desolventizing unit 16 and / or the operating temperature and / or pressure inside the unit.

[0041] The solvent evaporated from the partially desolventized extracted material 28 in the second desolventizing unit 16 to produce the desolventized extracted material 32 can be condensed in a condenser 16C operably connected to the second desolventizing unit. This can produce a second condensate stream 34, which can be a complete condensate of the vapor produced by the second desolventizing unit 16 or a partial condensate of the vapor produced by the unit (e.g., providing a mixed vapor-liquid phase). Generally speaking, the concentration of alcohol in the second condensate 34 can be less than the concentration of alcohol in the first condensate 30, and the concentration of water in the second condensate can be greater than the concentration of water in the first condensate.

[0042] Without wishing to be bound by any particular theory, the applicant has observed that the free water that intermixes with the alcohol to form the solvent that wets the solid material to be desolvated initially evaporates, wherein the amount of water evaporated is proportional to the amount of alcohol evaporated during the desolvation. This can allow the formation of a first condensate having a relatively low amount of water. As the solid material to be desolvated continues to be heated, the water chemically bound to the solid material to be desolvated begins to be released into the vapor, resulting in an increase in the concentration of water in the condensate. As the drying of the solid material proceeds, by separating the condensate formed during the desolvation into different streams, the condensate having a lower water concentration can be separated from the condensate having a higher water concentration to benefit downstream reuse and / or further processing.

[0043] In various applications, the weight fraction of water in the second condensate 34 (which may be reported as a percentage) may be greater than 2 wt % water, such as greater than 3 wt % water, greater than 3.5 wt % water, greater than 4 wt % water, greater than 4.5 wt % water, greater than 5 wt % water, greater than 5.5 wt % water, greater than 6 wt % water, greater than 6.5 wt % water, greater than 7 wt % water, greater than 8 wt % water, greater than 9 wt % water, or greater than 10 wt % water, based on the total weight of the condensate (e.g., including the combined weight of the alcohol and water that formed the condensate). The amount of water present in the second condensate 34 may be limited, for example, by the amount of water present in the partially desolventized extracted material 28 to be evaporated. Therefore, in combination with any of the aforementioned lower water concentration values, the weight fraction of water in the second condensate 34 can be within a range bounded by the following upper limit: less than 30 wt % water, such as less than 25 wt % water, less than 20 wt % water, less than 15 wt % water, less than 10 wt % water, less than 9 wt % water, less than 8 wt % water, less than 7 wt % water, less than 6 wt % water, or less than 5 wt % water, based on the total weight of the condensate.

[0044] The remaining weight of the second condensate 34 may be substantially or entirely alcohol evaporated from the solvent-wetted extracted solid material along with the water. Thus, the concentration of alcohol in the second condensate 34 may be greater than 70% alcohol by weight, such as greater than 75% alcohol by weight, greater than 80% alcohol by weight, greater than 85% alcohol by weight, greater than 90% alcohol by weight, greater than 91% alcohol by weight, greater than 92% alcohol by weight, greater than 93% alcohol by weight, greater than 94% alcohol by weight, or greater than 95% alcohol by weight, based on the total weight of the condensate. The amount of alcohol present in the second condensate 34 may be limited, for example, by the amount of water present in the condensate. Thus, in combination with any of the aforementioned lower alcohol concentration values, the concentration of alcohol in the second condensate 34 can be within a range bounded by an upper limit of less than 98 wt % alcohol, such as less than 97 wt % alcohol, less than 96.5 wt % alcohol, less than 96 wt % alcohol, less than 95.5 wt % alcohol, less than 95 wt % alcohol, less than 94.5 wt % alcohol, less than 94 wt % alcohol, less than 93 wt % alcohol, less than 92 wt % alcohol, less than 91 wt % alcohol, or less than 90 wt % alcohol, based on the total weight of the condensate.

[0045] If steam is injected (e.g., sparged steam) in the second desolventizing unit 16, the weight fraction of water in the second condensate 34 may be greater than (and the weight fraction of alcohol in the second condensate correspondingly lower than) the aforementioned values ​​and ranges. In some examples, the weight fraction of water in the second condensate 34 may be greater than 30% by weight of water, such as greater than 40% by weight of water, greater than 50% by weight of water, greater than 60% by weight of water, or greater than 70% by weight of water, based on the total weight of the condensate (e.g., including the combined weight of the alcohol and water that form the condensate). For example, the weight fraction of water in the second condensate 34 may be in the range of 30% by weight to 80% by weight, such as 40% by weight to 75% by weight or 50% by weight to 70% by weight of water, based on the total weight of the condensate. In each of the aforementioned examples, the remaining weight of the second condensate 34 may be substantially or entirely alcohol evaporated from the solvent-wetted extracted solid material along with the water. Therefore, the second condensate 34 may have a corresponding alcohol weight fraction of any of the aforementioned examples calculated by subtracting the water weight percentage from 100.

[0046] By separating the solvent evaporated from the solvent-wet extracted solid material into different condensate streams, the amount of water in each condensate stream can be varied. For example, the difference in the concentration of water in the second condensate 34 compared to the concentration of water in the first condensate 30 (e.g., the weight fraction of water in the second condensate 34 minus the weight fraction of water in the first condensate 30, which can be reported as a percentage) can be in the range of 1% to 15%, such as 2% to 10% or 3% to 5%. Even a small difference in the amount of water in one condensate stream compared to another condensate stream can be influential in commercial operations, such as where the condensate with the lower amount of water requires little or no further processing to remove excess water before reuse.

[0047] Each of the features described as desolventizing units (including the first desolventizing unit 14 and the second desolventizing unit 16) can be implemented using one or more stages of thermal treatment (optionally in combination with mechanical treatment) to remove solvent from the extracted solid material being processed. Each desolventizing unit can include a container that receives the extracted solid material to be desolventized and introduces thermal energy into the extracted solid material to be desolventized in the container. In different examples, each desolventizing unit can operate at positive pressure, atmospheric pressure, or vacuum pressure.

[0048] Each desolventizing unit can directly and / or indirectly heat the extracted solid material to be desolventized. The desolventizing unit can indirectly heat the extracted solid material by passing a heat transfer fluid through a tray in contact with the extracted material while passing through the desolventizing vessel and / or through a jacket surrounding at least a portion of the desolventizing vessel. Additionally or alternatively, the desolventizing unit can introduce a heated gas (e.g., dry air, nitrogen) that is substantially free of moisture into the interior of the desolventizing vessel and the extracted solid material therein. Still further additionally or alternatively, the desolventizing unit can introduce steam into the interior of the desolventizing vessel and the extracted solid material therein.

[0049] In some implementations, one or both of the first desolventizing unit 14 and the second desolventizing unit 16 are configured to operate without adding moisture to the extracted solid material that is desolventized in the desolventizing unit. For example, one or both of the first desolventizing unit 14 and the second desolventizing unit 16 can operate without injecting steam into the extracted solid material that is desolventized in the desolventizing unit. Implementing one or both of the first desolventizing unit 14 and the second desolventizing unit 16 to operate without injecting steam or other added water into the desolventized extracted solid material can be beneficial in minimizing the amount of water that is added to the system, which may then need to be separated from the alcohol to recover the alcohol for reuse in the extractor 12.

[0050] However, in some implementations, steam may be injected into one, but not both, of the first desolventizing unit 14 and the second desolventizing unit 16. For example, the first desolventizing unit 14 may be configured to operate without introducing steam or other added water into the extracted solid material desolventized in the unit. In contrast, the second desolventizing unit 16 may be configured to operate with steam injection, wherein steam is injected into the partially desolventized extracted material 28 introduced into the second desolventizing unit. In such implementations, processing the solvent-wet extracted solid material in the first desolventizing unit 14 in the absence of added steam may be beneficial in achieving a high alcohol concentration first condensate 30, for example, which may be recycled back to the extractor 12 with limited or no further water removal. In contrast, processing the partially desolventized extracted material 28 with added steam in the second desolventizing unit 16 may facilitate efficient desolventization and production of desolventized extracted material 32. While the added steam may further dilute the concentration of alcohol in the second condensate 34 (e.g., compared to operating the second desolventizing unit 16 in the absence of added steam), the second condensate may be further processed to remove excess water under either operating condition, and the additional steam added to the process may therefore not significantly alter downstream processing.

[0051] The first desolventizing unit 14 can be operated under a first set of evaporation conditions, and the second desolventizing unit 16 can be operated under a second set of evaporation conditions. The evaporation conditions can be a set of process parameters that indicate the extent to which solvent is evaporated from the extracted solid material being processed in each respective desolventizing unit and the composition of the resulting condensate produced by the desolventizing unit, respectively. For example, the evaporation conditions of any desolventizing unit can be determined at least in part by the operating temperature and / or temperature profile of the unit, the operating pressure, and the heat transfer configuration of the unit (e.g., direct and / or indirect heat transfer, addition and / or absence of steam injection).

[0052] In some applications, the second set of evaporation conditions under which the second desolventizing unit 16 operates is the same as the first set of evaporation conditions under which the first desolventizing unit 14 operates. In these applications, the desolventizing of the extracted solid material can be split between different desolventizing units to facilitate the production of different condensate streams having different compositions, but otherwise processed under substantially the same conditions in each desolventizing unit. However, in other applications, the second set of evaporation conditions under which the second desolventizing unit 16 operates is different from the first set of evaporation conditions under which the first desolventizing unit 14 operates. For example, the second desolventizing unit 16 can operate at a different temperature (e.g., a higher temperature), a different pressure, and / or different heat transfer conditions (e.g., the addition of steam) than the first desolventizing unit 14.

[0053] The desolventizing unit according to the present disclosure can be implemented using a variety of different processing units during implementation. In different examples, the desolventizing unit can be implemented using a digester, a jacketed paddle mixer, a bulk solid heat exchanger, a desolventizer-oven, a rotary disc dryer, a downdraft desolventizer and / or a flash dryer. In applications utilizing multiple desolventizing units, each desolventizing unit can be implemented using the same type of process equipment, or a desolventizing unit can be implemented using process equipment of a different type from another desolventizing unit. In some examples, the first desolventizing unit 14 is implemented using a rotary disc dryer, a desolventizing unit-oven, a downdraft desolventizer, a flash dryer, or a combination thereof. In these examples, the second desolventizing unit 16 can be implemented using a desolventizing oven, a downdraft desolventizer, a flash dryer, or a combination thereof.

[0054] In some examples, the first condensate 30 produced by the first desolventizing unit 14 and the second condensate 34 produced by the second desolventizing unit 16 each provide a recovered solvent (e.g., alcohol) for reuse in the extraction system 10. For example, the first condensate 30 produced by the first desolventizing unit 14 and the second condensate 34 produced by the second desolventizing unit 16 can provide a recovered solvent that is recycled back to the solvent inlet 24 of the extractor 12 for reuse in extracting additional incoming solid material entering through the feed inlet 20 of the extractor.

[0055] The first condensate 30 and the second condensate 34 may or may not undergo additional processing prior to being recycled back to the extractor 12. For example, the first condensate 30 and / or the second condensate 34 may be filtered to reduce the amount of particulates present in the condensate prior to being returned to the extractor 12. In some examples, the first condensate 30 and / or the second condensate 34 are processed to reduce the amount of water present in the condensate, thereby increasing the alcohol concentration in the condensate to a level suitable for returning the condensate as an incoming solvent stream to the solvent inlet 24 of the extractor 12 and / or other desired downstream uses.

[0056] The first condensate 30 and / or the second condensate 34 may be treated using a variety of different techniques to remove water from the condensate. As discussed above, when an alcohol solvent such as ethanol is used, water and the alcohol may form an azeotropic mixture that is difficult to separate to recover the solvent. In these applications, water cannot be easily removed from the alcohol using distillation or other thermal separation methods based on the different vapor pressures. In these and other applications, non-thermal separation techniques such as adsorption and / or membrane separation methods may be used to remove water from the condensate to increase the alcohol concentration in the condensate.

[0057] While one or both of the first condensate 30 and the second condensate 34 may be treated to remove water from the condensate, thereby providing a high alcohol concentration solvent for recycling and / or reuse, in some implementations, the first condensate 30 is recycled back to the extractor 12 without further removing water, and the second condensate 34 is further treated to remove water before being recycled back to the extractor. For example, the first condensate 30 produced by the first desolventizing unit 14 may be recycled back to the solvent inlet 24 of the extractor 12 without treating the condensate to reduce the water concentration in the condensate prior to reintroduction into the extractor. In contrast, the second condensate 34 produced by the second desolventizing unit 16 may be treated to reduce the water concentration in the condensate, and then the treated condensate having the resulting reduced water concentration may be reintroduced into the extractor. By producing different condensate streams having different alcohol and water concentrations as described herein, the first condensate 30 may have a sufficiently high alcohol concentration and a sufficiently low water concentration to allow the condensate to be directly reused without dehydration. This may provide processing and efficiency advantages compared to a single condensate stream which produces a larger volume but requires dehydration prior to recycling to the extractor 12 .

[0058] exist Figure 1 In the example of , the extraction system 10 is shown to include a water removal unit 36 ​​that receives the second condensate 34 produced by the second desolventizing unit 16. The water removal unit 36 ​​can process the received second condensate 34 and separate water from the condensate to increase the alcohol concentration and the received second condensate stream for recycling back to the extractor 12 and / or other uses. For example, the water removal unit 36 ​​can separate water from the received second condensate 34 to produce a second condensate alcohol recovery stream 38 having an increased alcohol concentration compared to the second condensate 34 and the separated water 40.

[0059] In various examples, the water removal unit 36 ​​can be implemented using one or more molecular sieves (mole sieves), one or more pervaporation systems, and / or one or more vapor permeation membranes. Generally speaking, molecular sieves utilize materials with small pore sizes to allow relatively small molecules (e.g., water) to enter the back side for interception, while relatively large molecules (e.g., alcohols) cannot enter the molecular pores. The molecular sieve can be regenerated regularly, for example, by heating and purging with a carrier gas or under vacuum to remove the separated water 40 trapped in the sieve. In contrast, pervaporation generally involves a method of separating a mixture of liquids by partial evaporation through a non-porous or porous membrane. The pervaporation process can be performed as follows: a continuous flow of separated water 40 is produced from the second condensate alcohol recovery stream 38 by initial permeation of the permeate through the membrane, followed by evaporation into a gas phase.

[0060] If a specific water removal technology is used, such as molecular sieves or vapor permeation membranes, water can be removed from the solvent vapor before condensation. In these specific implementations, the water removal unit 36 ​​can be positioned between the desolventizing unit and the condenser, rather than downstream of the condenser, as shown in the exemplary figure.

[0061] Independent of the configuration of the water removal unit 36, the water removal unit may reduce the concentration of water in the second condensate 34 by at least one weight percent, such as at least two weight percent, at least three weight percent, at least four weight percent, or at least five weight percent, based on the total weight of the second condensate 34. For example, based on the total weight of the second condensate 34, the water removal unit 36 ​​may reduce the concentration of water and the second condensate 34 by an amount in a range of two weight percent to 25 weight percent, such as three weight percent to 15 weight percent, three weight percent to 10 weight percent, or three weight percent to seven weight percent.

[0062] After the second condensate 34 is optionally treated by a water removal unit 36 ​​to produce a second condensate alcohol recovery stream 38, the second condensate alcohol recovery stream may be recycled back to the extractor 12. For example, the second condensate alcohol recovery stream 38 may provide recovered solvent that is recycled back to the solvent inlet 24 of the extractor 12 for reuse in extracting additional incoming solid material entering through the extractor's feed inlet 20. In implementation, the streams described as being recycled back to the extractor 12, such as the first condensate 30 and the second condensate alcohol recovery stream 38, may be supplied to one or more solvent tanks, which are then withdrawn from the solvent tanks to supply incoming solvent to the solvent inlet 24 of the extractor 12.

[0063] 10, the extraction system 10 is shown as being implemented with a plurality of different desolventizing units 14, 16, each of which is configured to produce a different condensate stream 30, 34 having different concentrations of alcohol and water. In implementation, the techniques of the present disclosure may be implemented using alternative configurations of the extraction system 10 having a fewer number of desolventizing units (one desolventizing unit) or more desolventizing units (e.g., three, four, or more).

[0064] Figure 2 is a block diagram illustrating another exemplary extraction system 50 according to the present disclosure, wherein solvent-wet extracted solid material is desolventized in a single desolventizing unit 52 to produce multiple condensate streams (first condensate 30, second condensate 34), albeit from a single vessel as opposed to using multiple vessels. Figure 2 In the example above, Figure 1 Similar reference numerals discussed herein refer to similar parts. Figure 1 The exemplary materials, compositions, and processing parameters (e.g., temperature, pressure, alcohol concentration, water concentration) discussed also apply to Figure 2of the system 50 unless otherwise indicated.

[0065] Figure 2 The system 50 in the embodiment includes the extractor 12 and the desolventizing unit 52 described previously. Figure 1 Unlike system 10, system 50 is shown as being implemented with a single desolventizing unit 52 (e.g., a single vessel). Figure 2 In the operation of the system, the solid material to be processed can be optionally dried by the dryer 18 and supplied to the extractor 12. The extractor 12 can discharge the solvent-wetted extracted solid material through the feed outlet 22 after the solid material has undergone extraction in the extractor and has a lower extract concentration than the fresh incoming material. The extractor 12 can also discharge the mixed oil formed by extracting the extractable components from the solid material through the solvent outlet 26.

[0066] The solvent-wet extracted solid material discharged from the extractor 12 through the feed outlet 22 can be desolventized by the desolventizing unit 52. The desolventizing unit 52 can evaporate solvent from the solvent-wet extracted solid material supplied to the unit as the extracted solid material is conveyed through the unit (e.g., under gravity and / or via mechanical conveyance). The desolventizing unit 52 can include a plurality of vapor discharge outlets / streams positioned at different locations along the desolventizing unit, each of which is configured to provide vapor generated by the solvent-wet extracted solid material having different concentrations of alcohol and water.

[0067] For example, the desolventizing unit 52 can receive the solvent-wetted extracted solid material through the feed inlet 54 and evaporate a portion of the solvent from the extracted solid material in the desolventizing unit 52, thereby producing a partially desolventized extracted material inside the unit. The partially desolventized extracted material can continue to be conveyed through the desolventizing unit 52, further evaporating the solvent from the partially desolventized extracted material as the material continues to move through the desolventizing unit. This can produce a desolventized extracted material that is discharged from the feed outlet 56 of the desolventizing unit.

[0068] The desolventizing unit 52 may include a first vapor outlet 58 through which solvent evaporated from the solvent-wetted extracted solid material may exit. The vapor discharged through the first vapor outlet 58 may be condensed in a condenser 52C1 operably connected to the desolventizing unit to produce a first condensate stream 30. The desolventizing unit 52 may include a second vapor outlet 60 through which solvent evaporated from the partially desolventized extracted material may exit. The vapor discharged through the second vapor outlet 60 may be condensed in a condenser 52C2 operably connected to the desolventizing unit to produce a second condensate stream 34. The first condensate 30 and the second condensate 34 may have the same properties as described above with respect to Figure 2 The components discussed in the extraction system 10 may be reused and / or further processed.

[0069] The desolventizing unit 52 can be implemented using any suitable type of process equipment configured to perform the functions described herein. In some examples, the desolventizing unit 52 is implemented as a desolventizing oven (DT), which may or may not dry and further "bake" or brown the outer surface of the solid material being processed, for example, resulting in the denaturation of proteins present in the processed material.

[0070] In some examples, the desolventizing unit 52 includes a container containing a plurality of trays 62. The trays 62 can be arranged vertically relative to each other in a stacked arrangement relative to gravity. Although the illustrated exemplary desolventizer has four trays, the desolventizer can be designed to have fewer trays (e.g., two or three trays) or more trays (e.g., six, seven or more), and the present disclosure is not limited in this regard.

[0071] In operation, the material to be dried may enter the housing of the desolventizing unit 52 through the feed inlet 54 and flow vertically downward through the desolventizer before exiting through the feed outlet 56. As the material to be dried flows through the desolventizer, the material may flow through each of the corresponding trays in the desolventizer. The material may or may not physically contact the top surface of each of the trays, depending on whether the material flows on top of the underlying material as it passes through a particular tray.

[0072] Each tray 62 can have one or more outlet openings that allow material to flow through the tray and down to the tray below or to the outlet 56 (e.g., after a desired residence time on a particular tray). The one or more discharge ports can be located at any suitable location on the tray, such as centered on the tray or offset to one side of the tray. A rotating scanning arm can be positioned on the top surface of each tray or a small distance above the top surface of each tray to mechanically sweep solid material being processed around the processing space defined by the tray. The rotating scanning arm can provide a mixing function, which is used to mix the solid material being processed with a gas to promote desolventization, as well as a conveying function, which is used to push the solid material being processed from the opening of the upper tray to the outlet of the lower tray. For example, the rotating scanning arm can have a curved or angled blade to direct the material pushed by the rotating scanning arm toward an opening located at the center of the tray.

[0073] The desolventizing unit 52 can heat and dry (by evaporating the solvent) the solvent-wetted extracted solid material introduced into the device. A variety of different direct and / or indirect heating sources can be used to provide thermal energy to the solid material being dried. For example, one or more (e.g., all) trays 62 can provide indirect heating to the solid material being processed. Each such tray can have an opening across its thickness that allows a heat transfer fluid (e.g., steam) to pass through the tray and heat the tray without causing the heat transfer fluid to enter the space through which the solid material being dried flows. Additionally or alternatively, one or more of the trays 62 can provide direct heating, for example, by having a steam jet that injects steam upward through the tray into the material being processed. The sidewalls of the container shell may or may not be heated.

[0074] For example, different trays of a desolventizer unit may be heated differently depending on the position of the trays within the desolventizer. The topmost tray or trays (e.g., the top two or three trays depending on the size of the vessel) may be pre-desolventizing trays. These trays may use indirect heating to flash solvent from the solvent-wetted solid material as the solvent-wetted solid material contacts the hot tray surfaces. However, the pre-desolventizing trays may not have a direct heat source (e.g., steam injection) to avoid adding additional moisture to the solvent-wetted solid material being processed in these trays.

[0075] The main tray or intermediate trays (e.g., one, two, three, four or five trays in the middle depending on the size of the container) can provide indirect heating and direct steam contact to remove most of the solvent from the solvent-wetted solid. This will also increase the moisture in the solvent-wetted solid, for example, when steam is required to cook the material, such as when processing residual solids from oilseed raw materials. In different configurations, direct steam contact can be provided by having a steam distribution manifold below the tray and allowing steam to permeate upward through the tray and / or by injecting steam as a gas source above the tray. For example, some configurations of the desolventizing unit 52 can include an intermediate tray that is indirectly heated but does not have a direct heat source that adds heat energy below the tray or by the tray. On the contrary, in these examples, direct heat (if optional) can be supplied as a power gas source that drives the heat energy recirculation loop in the space above the tray.

[0076] The bottom one or more trays (e.g., the bottom two or three trays depending on the size of the container) can be injection trays. The injection trays can be perforated to direct injection steam injection, which can strip the final residual solvent from the solid material being processed and discharge upward through the desolventizer to the second outlet 60. However, in other configurations, the bottom one or more trays may not be injection trays. For example, the bottom one or more trays can provide indirect heating without any direct heat injection, or can even be unheated and / or cooled trays to cool the solid material before discharge from the desolventizing unit. A variety of other configurations of the desolventizing unit 52 can be used, and the present disclosure is not limited to the foregoing examples.

[0077] The extractor 12 in any of the foregoing examples can be implemented using any suitable type of extractor configuration. For example, the extractor 12 can be an immersion extractor, a percolation extractor, or other type of extractor design. In one example, the extractor 12 is a shallow bed continuous loop extractor.

[0078] Figure 3 1 is a diagram of an exemplary extractor configuration that can be used for extractor 12. In the example shown, extractor 12 includes a housing defining a channel in the form of a ring disposed in a vertical plane. The extractor may include an upper extraction section 80 and a lower extraction section 82 each having a series of extraction chambers, a generally arcuate hollow transfer section 84 having an upper end and a lower end that are respectively connected to the first end of the upper extraction section and the lower extraction section, and a hollow generally vertical return section 86 that is respectively connected to the other end of the upper extraction section and the lower extraction section. The upper extraction section may include an inlet portion 88 for delivering solid materials to its interior in a relationship that is closely spaced apart from the upper end of the return section, and the lower end of the return section may define an opening 90 for discharging materials after the product of interest has been extracted therefrom. The number of extraction chambers or extraction stages provided by the extractor may vary according to the desired size of the extractor. The extractor includes at least one extraction chamber or extraction stage, and typically includes a plurality of stages (e.g., 6, 8 or more stages). A Type III extractor commercially available from Crown Iron Works Company of Minneapolis, Minnesota is a specific example of this type of extractor.

[0079] In such extractors, a conveyor system 92 may extend longitudinally through the annular passage and be driven in the material flow direction "M" to move the material as a bed from the inlet portion 88 through the upper extraction section 80 toward and downward through the transfer section 84, and through the lower extraction section 82 toward the lower end of the return section and the discharge opening 90. In some embodiments, the conveyor system includes a pair of laterally spaced endless endless chains and a plurality of longitudinally spaced scrapers extending transverse to the chains. A motor and transmission may be provided to drive the conveyor.

[0080] In some configurations, a fluid supply system 94 can be disposed above the solid material and configured to apply fluid to the solid material in each extraction chamber, and a fluid removal system 96 can be disposed below the solid material and configured to remove the fluid after the fluid has passed through the solid material in each extraction chamber. In some embodiments, the fluid supply system and the fluid removal system are connected by fluids such as various recirculating streams. The fluid supply system can include a network of spray headers, pumps, and pipes to apply the fluid in each extraction chamber. The fluid supply system can apply (e.g., spray) the extraction fluid on top of the transported solid material, thereby allowing the extraction fluid to then penetrate through the material. The fluid removal system can include a network of drains, pumps, and pipes to collect the fluid after the fluid has penetrated through the solid material in each extraction chamber and deliver it to the fluid supply system of another extraction chamber or remove it from the system.

[0081] like Figure 3 As shown, the fluid that has passed through the solid material is collected by a fluid removal system 96 and delivered to a separation device 98, which is shown in the illustrated example as a cyclone-type separator to separate any solid fines from the fluid before the fluid is discharged. An outlet conduit 100 of the separation device 98 can deliver the fluid (typically a mixture of extraction fluid and soluble components extracted from the solid material into the extraction fluid (e.g., oil when processing oilseeds) (commonly referred to as "mixed oil") to other equipment (not shown) for separating the extraction fluid from the material extracted from the solid material being processed. A separate outlet 102 of the separation device 98 can deliver a stream containing particulate matter separated from the mixed oil for further processing, as described herein.

[0082] As the material is conveyed through the extractor 12, a spray manifold from the fluid supply system 94 sprays recycled extraction fluid on top of the material. The material permeates through the material and passes through the screen, where it is collected in a network of drain pipes and delivered back to the spray manifold network, where it is reapplied to the solid material in a different extraction chamber. In some embodiments, fresh extraction fluid is applied to the material in the last extraction chamber before the solid material is discharged 90. For example, fresh extraction fluid (which can be or include solvent recovered from one or more desolventizers as discussed herein) can be applied to the material in the last extraction chamber before discharge 90 and, after being collected at the bottom of the chamber, recycled and applied to the top of the solid material in an adjacent upstream extraction chamber. By recycling the collected extraction fluid from one extraction chamber to an adjacent upstream extraction chamber, the liquid extraction fluid and the solid material being processed can move through the extractor in a countercurrent direction. For example, as the extraction fluid is conveyed sequentially through adjacent extraction chambers between a fresh extraction fluid inlet adjacent to discharge 90 and an enriched extraction fluid outlet adjacent to inlet 88, the concentration of the extract relative to the extraction fluid increases from a relatively small extract to extraction fluid ratio to a relatively large extract to extraction fluid ratio. Similarly, as the solid material is conveyed in the opposite direction, the concentration of the extract in the solid feedstock decreases from a relatively high concentration at inlet 88 to a relatively low concentration at outlet 90.

[0083] Compared to extraction methods that do not use alcohol-based solvents, the alcohol-based solvent extraction methods according to the present disclosure can provide various advantages. For example, alcohol-based solvents can provide better compatibility with the food supply chain. Ethanol is GRAS (generally recognized as safe), can be produced in an organic manner from renewable raw materials, and has been directly consumed as a component of alcoholic beverages. As another example, alcohol-based solvents can improve the processed product properties of some raw materials. For example, when applied to soy flakes, alcohol-based solvents can produce foods with less "beany smell" and less color. When applied to soy flakes or cottonseed meat, alcohol-based solvents can change protein solubility and reduce anti-nutritional factor content. Alcohol-based solvents can produce oils with lower wax and phospholipid content.

[0084] The following examples may provide additional details regarding extraction and desolventization systems and techniques according to the present disclosure.

[0085] Example

[0086] Experiments were conducted to study the composition of the liquid evaporated over time from an extraction material wetted with an exemplary solvent during desolventization. The material used for the experiment was defatted soy flakes produced during a previous extraction run, which were dried and stored in a sealed container. A solvent mixture of ethanol and water was prepared, and the defatted soy flakes were soaked in the solvent for a period of time sufficient to reach equilibrium. After the equilibrium period, the soy flakes were drained using a screen similar to the drainage screen used on the Crown Model III extractor. The water content of the drained solvent was then measured via a mass balance to determine the mass of solvent in the soy flakes before desolventization.

[0087] The solvent-wetted extracted soy flakes were then desolventized using an experimental desolventizer. The experimental device utilized a heated water / oil bath in which a closed desolventizer container was placed. A stirrer was positioned in the desolventizer container to stir the soy flakes inside the desolventizer container during desolventization. In addition, a condenser was positioned to condense the solvent evaporated through the exhaust port of the desolventizer container. A pump was also provided to recirculate the motive air through the desolventizer container through the corresponding port. The desolventizer was operated at atmospheric pressure. The first run was performed using an applied surface temperature of 120 degrees Celsius (applied to the desolventizer container). The second run was performed using an applied surface temperature of 83 degrees Celsius (applied to the desolventizer container). In each case, the solvent-wetted extracted material was desolventized for a certain amount of time until the condensate stopped flowing (less than 10 drops in 15 to 20 minutes) based on visual observation.

[0088] The condensate from the device was collected in fractions and the corresponding water content of each sample was measured. The mass of solvent in each sample was also measured. The soy flake ethanol was calculated using this data together with the post-desolventization weight of the desolventized soy flakes and attributed to the loss of evaporation and glassware liquid film.

[0089] Figure 4 is a graph of the concentration of water in the condensate produced by the desolventizer on the Y-axis versus the concentration of ethanol in the soy flakes during drying on the X-axis. The water concentration is expressed as a weight percent based on the total weight of the condensate (where the corresponding ethanol concentration is 100% minus the reported water concentration). The ethanol concentration in the soy flakes is expressed as a weight percent of ethanol based on the total weight of the solvent-wetted material being desolventized during drying (the weight of the soy flakes, ethanol, and water). Data from two different runs are presented in Figure 4 middle.

[0090] As shown, the concentration of water in the condensate produced during desolventization remains at a substantially constant level of about 2 wt % (e.g., 1.5 wt % to 4 wt %) when the solvent-wet material being desolventized is dried from an alcohol concentration level of about 30 wt % to an alcohol concentration level of about 5 wt % (e.g., 4 wt % to 6 wt %). At an alcohol concentration level of about 5 wt %, the concentration of water in the condensate increases dramatically to multiples of the concentration previously observed.

Claims

1. A method, comprising: extracting the material to be treated with a solvent comprising an alcohol in an extractor to produce an extracted material stream and a mixed oil stream, the extracted material stream comprising extracted solid material wetted with a liquid comprising alcohol and water; desolventizing the extracted material stream to a first alcohol level, thereby producing a partially desolventized extracted material and a first condensate, wherein the first condensate comprises water and the alcohol; The partially desolventized extracted material is desolventized to a second alcohol level that is lower than the first alcohol level, thereby producing a desolventized extracted material and a second condensate, wherein the second condensate comprises water and the alcohol, and the weight fraction of water in the second condensate is greater than the weight fraction of water in the first condensate.

2. The method of claim 1 , wherein desolventizing the extracted material stream to the first alcohol level and desolventizing the partially desolventized extracted material to the second alcohol level comprises desolventizing the extracted material stream to the first alcohol level and desolventizing the partially desolventized extracted material to the second alcohol level in a single desolventizing vessel.

3. The method of claim 2, wherein desolventizing the extracted material stream to the first alcohol level and desolventizing the partially desolventized extracted material to the second alcohol level in the single desolventizing vessel comprises: conveying the extracted material stream through the single desolventizing vessel and heating the extracted material stream as the extracted material stream is conveyed through the single desolventizing vessel; withdrawing a first vapor stream from the single desolventizing vessel and condensing the first vapor stream in a first condenser to form the first condensate; and A second vapor stream is withdrawn from the single desolventizing vessel and condensed in a second condenser to form the second condensate.

4. The method according to claim 3, wherein: conveying the extracted material stream through the single desolventizing vessel and heating the extracted material stream while conveying the extracted material stream through the single desolventizing vessel comprises gradually desolventizing the extracted material stream through the single desolventizing vessel; The partially desolventized extracted material is defined by the extracted material stream in the single desolventizing vessel downstream of the extraction location of the first vapor stream; and The desolventized extracted material is the effluent product from the single desolventizing vessel.

5. The method according to claim 1, wherein: desolventizing the extracted material stream to the first alcohol level comprises desolventizing the extracted material stream in a first desolventizing vessel; and Desolventizing the partially desolventized extracted material includes desolventizing the partially desolventized extracted material in a second desolventizing vessel that is different from the first desolventizing vessel.

6. The method according to claim 5, wherein: desolventizing the extracted material stream in the first desolventizing vessel comprises conveying the extracted material stream from the extractor to the first desolventizing vessel and evaporating solvent from the extracted material stream in the first desolventizing vessel under a first set of evaporation conditions; and Desolventizing the partially extracted material in the second desolventizing vessel includes transferring the partially extracted material from the first desolventizing vessel to the second desolventizing vessel and evaporating solvent from the partially extracted material in the second desolventizing vessel under a second set of evaporation conditions.

7. The method of claim 6, wherein the first set of evaporation conditions differs from the second set of evaporation conditions in one or more of temperature, pressure, and added flow.

8. The method according to any one of claims 5 to 7, wherein: desolventizing the extracted material stream in the first desolventizing vessel comprises desolventizing the extracted material stream in the first desolventizing vessel without injecting steam into the first desolventizing vessel; and Desolventizing the partially extracted material in the second desolventizing vessel includes introducing steam into the second desolventizing vessel.

9. The method according to any one of claims 5 to 8, wherein: The first desolventizing vessel is selected from the group consisting of a rotary disc dryer, a desolventizer-oven, a downdraft desolventizer, a flash dryer, and combinations thereof; and The second desolventizing vessel is selected from the group consisting of a desolventizer-oven, a downdraft desolventizer, a flash dryer, and combinations thereof.

10. The method according to any one of claims 1 to 9, wherein the extractor is a continuous extractor and extracting the material to be treated with the solvent comprises conveying the material to be treated through the extractor in a conveying direction and conveying the solvent through the extractor in a direction countercurrent to the conveying direction.

11. The method of any one of claims 1 to 10, wherein the extractor comprises a solvent inlet, and the method further comprises recycling the first condensate back to the solvent inlet without further treatment to remove water from the first condensate.

12. The process of any one of claims 1 to 11, further comprising treating the second condensate to separate the alcohol in the second condensate from water in the second condensate to form a second condensate alcohol recovery stream.

13. The method of claim 12, wherein treating the second condensate to separate the alcohol in the second condensate from the water in the second condensate comprises treating the second condensate in a molecular sieve and / or a pervaporation system.

14. The process of claim 12 or 13, further comprising recycling the second condensate alcohol recovery stream to the fresh solvent inlet of the extractor.

15. The method of any one of claims 1 to 14, wherein the first alcohol level is less than 20 wt % and greater than 3 wt % of the weight of the partially desolventized extracted material, such as less than 12 wt % and greater than 3 wt % of the weight of the partially desolventized extracted material, less than 10 wt % and greater than 5 wt % of the weight of the partially desolventized extracted material, or a value in the range of 5 wt % to 10 wt % of the weight of the partially desolventized extracted material.

16. The process according to any one of claims 1 to 15, wherein the first condensate stream comprises greater than 90 wt% alcohol and less than 10 wt% water, such as greater than 95 wt% alcohol and less than 5 wt% water or greater than 98 wt% alcohol and less than 2 wt% water.

17. The method according to any one of claims 1 to 16, wherein: desolventizing the partially desolventized extracted material to the second alcohol level comprises desolventizing the partially desolventized extracted material to the second alcohol level in the absence of injected steam, and The second alcohol level is a value less than 15% by weight of the desolventized extracted material, such as less than 5% by weight of the desolventized extracted material, less than 3% by weight of the desolventized extracted material, less than 1% by weight of the desolventized extracted material, less than 0.5% by weight of the desolventized extracted material, or less than 0.25% by weight of the desolventized extracted material.

18. The process of claim 17, wherein the second condensate stream comprises greater than 75 wt% alcohol and 2 to 25 wt% water, such as greater than 85 wt% alcohol and 3 to 15 wt% water, greater than 90 wt% alcohol and 4 to 10 wt% water, or greater than 92 wt% alcohol and 4 to 8 wt% alcohol.

19. The method according to any one of claims 1 to 18, wherein the difference between the weight fraction of water in the second condensate minus the weight fraction of water in the first condensate is a value in the range of 2% to 10%, such as 3% to 5%.

20. The method according to any one of claims 1 to 19, wherein: desolventizing the partially desolventized extracted material to the second alcohol level comprises desolventizing the partially desolventized extracted material to the second alcohol level with the addition of injected steam, and The second alcohol level is a value of less than 5% by weight of the desolventized extracted material, such as less than 2% by weight of the desolventized extracted material.

21. The method of any one of claims 1 to 20, wherein the extracted material stream from the extractor prior to desolventizing comprises 30 wt% to 50 wt% solvent, such as 35 wt% to 45 wt% solvent, based on the total weight of the extracted material stream.

22. A method according to any one of claims 1 to 21, wherein the desolventized extracted material comprises less than 5000 ppm alcohol, such as less than 1000 ppm alcohol.

23. The method of any one of claims 1 to 22, wherein the alcohol comprises ethanol.

24. The method of claim 23, wherein the solvent comprises greater than 90 wt% ethanol and less than 10 wt% water, such as greater than 95 wt% ethanol and less than 5 wt% water or greater than 98 wt% ethanol and less than 2 wt% water.

25. The method according to any one of claims 1 to 24, wherein the material to be treated comprises one of soybean and rapeseed.

26. The method according to any one of claims 1 to 25, further comprising drying the material to be treated before conveying it through the extractor in the conveying direction.

27. The method of claim 26, wherein drying the material to be treated comprises drying the material to be treated to a moisture content of 5 wt% or less, such as 3 wt% or less, or 2 wt% or less.

28. An extractor system, the extractor system comprising: an extractor having a feed inlet configured to receive a material to be processed and a solvent inlet configured to receive a solvent comprising an alcohol, the extractor being configured to mix the material to be processed with the solvent within an extraction chamber, thereby producing a mixed oil stream and an extracted material stream comprising extracted solid material wetted with a liquid comprising an alcohol and water; and at least one desolventizer, the at least one desolventizer being configured to: receiving a stream of said extracted material from said extractor; desolventizing the extracted material stream to a first alcohol level, thereby producing a partially desolventized extracted material and a first vapor stream; as well as The partially desolventized extracted material is desolventized to a second alcohol level that is lower than the first alcohol level, thereby producing a desolventized extracted material and a second vapor stream, wherein the weight fraction of water in the second vapor stream is greater than the weight fraction of water in the first vapor stream.

29. The system of claim 28, further comprising at least one condenser, the at least one condenser being configured to: receiving the first vapor stream and condensing the first vapor stream to produce a first condensate, wherein the first condensate comprises water and the alcohol; and The second vapor stream is received and condensed to produce a second condensate, wherein the second condensate comprises water and the alcohol, and wherein a weight fraction of water in the second condensate is greater than a weight fraction of water in the first condensate.

30. The system of claim 29, further comprising a water removal unit configured to receive the second condensate and separate the alcohol in the second condensate from water in the second condensate to form a second condensate alcohol recovery stream.

31. The system of claim 30, wherein the first condensate and the second condensate alcohol recovery streams are recycled back to the solvent inlet of the extractor.

32. The system of any one of claims 28 to 31, wherein the at least one desolventizer is a single desolventizing vessel comprising: an inlet configured to receive the extracted material flow from the extractor; an outlet configured to discharge the desolventized extracted material; a first vapor outlet configured to discharge the first vapor flow; as well as A second vapor outlet is located downstream of the first vapor outlet in the direction of solid material flow, the second vapor outlet being configured to discharge the second vapor flow.

33. The system of claim 28, wherein the at least one desolventizer comprises: a first desolventizing vessel configured to receive the extracted material stream from the extractor, desolventize the extracted material stream to the first alcohol level and discharge the partially desolventized extracted material; as well as a second desolventizing vessel configured to receive the partially desolventized extracted material from the first desolventizing vessel, desolventize the partially desolventized extracted material to the second alcohol level and discharge the desolventized extracted material.

34. A system according to claim 33, wherein the first desolventizing vessel is configured to operate under a first set of evaporation conditions, the second desolventizing vessel is configured to operate under a second set of evaporation conditions, and the first set of evaporation conditions is different from the second set of evaporation conditions in one or more aspects of temperature, pressure, and added flow.

35. A system according to claim 33 or 34, wherein the first desolventizing vessel is configured to operate without injecting steam into the first desolventizing vessel, and the second desolventizing vessel is configured to operate with introducing steam into the second desolventizing vessel.

36. A system according to any one of claims 33 to 35, wherein: The first desolventizing vessel is selected from the group consisting of a rotary disc dryer, a desolventizer-oven, a downdraft desolventizer, a flash dryer, and combinations thereof; and The second desolventizing vessel is selected from the group consisting of a desolventizer-oven, a downdraft desolventizer, a flash dryer, and combinations thereof.

37. A system according to any one of claims 28 to 36, wherein the extractor is a continuous extractor having the feed inlet on one side of the extraction chamber and the solvent inlet on an opposite side of the extraction chamber, thereby being configured to flow the material to be treated through the extraction chamber in a direction countercurrent to the solvent.

38. A system according to any one of claims 28 to 37, wherein the first alcohol level is less than 20 weight % and greater than 3 weight % of the weight of the partially desolventized extracted material, such as less than 12 weight % and greater than 3 weight % of the weight of the partially desolventized extracted material, less than 10 weight % and greater than 5 weight % of the weight of the partially desolventized extracted material, or a value in the range of 5 weight % to 10 weight % of the weight of the partially desolventized extracted material.

39. A system according to any one of claims 28 to 38, wherein the second alcohol level is less than 15 weight % of the desolventized extracted material, such as less than 5 weight % of the desolventized extracted material, less than 3 weight % of the desolventized extracted material, less than 1 weight % of the desolventized extracted material, less than 0.5 weight % of the desolventized extracted material, or less than 0.25 weight % of the desolventized extracted material.

40. The system of any one of claims 28 to 39, wherein the extracted material stream from the extractor comprises 30 wt% to 50 wt% solvent, such as 35 wt% to 45 wt% solvent, based on the total weight of the extracted material stream.

41. The system of any one of claims 28 to 40, wherein the solvent comprises greater than 90 wt% ethanol and less than 10 wt% water, such as greater than 95 wt% ethanol and less than 5 wt% water or greater than 98 wt% ethanol and less than 2 wt% water.

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