Foam control agents

Abstract

The present invention relates to a foam control agent and a method for controlling foam for bioethanol processing by using the foam control agent, the agent comprising at least a branched chain alcohol.

Description

Technical Field

[0001] Embodiments relate to foam control agents and methods for controlling foam for bioethanol processing, the agent comprising at least a branched-chain alcohol.

[0002] Introduction Ethanol may be produced by a biological fermentation process from sugarcane raw materials. Such ethanol is called bioethanol (sometimes referred to as bio-ethanol), and the process of producing this ethanol often encounters difficulties due to the presence of foam produced by yeast in the production medium. Yeast is added to a fermenter with a continuous supply of sugarcane raw materials to produce bioethanol. Uncontrolled foaming in these tanks can result in a significant loss of production capacity. Foaming can cause overflow, resulting in spillage and waste of the product. Foaming during ethanol production is a major issue, and thus mechanical methods of foam management have been devised with limited effectiveness.

[0003] Foam control agents (FCA) are widely considered to be more practical than mechanical methods and are currently more commonly used across the industry to minimize production losses due to foaming. These foam control agents can include both defoaming chemicals and antifoaming chemicals. An antifoaming agent (technical term) is designed to prevent foam, while a defoaming agent (another technical term) eliminates existing foam.

[0004] For fermentation applications, foam control agents typically contain block copolymers (polyglycols) consisting of ethylene oxide, propylene oxide, and / or butylene oxide. These types of products are effective because they are considered insoluble in solution at high temperatures, thereby increasing the surface tension of the system, which in turn causes foam collapse. Generally, these materials are combined with other hydrophobic materials to improve foam control properties. The use of these foam control agents is important to the industry, and therefore any novel or improved foam control agent is highly valuable.

[0005] For all these reasons, there is a need for foam control agents and methods for controlling foam during bioethanol processing. [Overview of the project]

[0006] The embodiments relate to a foam control agent and a method for controlling foam for bioethanol treatment, wherein the agent comprises at least a branched-chain alcohol. [Modes for carrying out the invention]

[0007] This disclosure relates to foam control agents for bioethanol production. As previously stated, ethylene oxide, propylene oxide, and / or butylene oxide are commonly used foam control agents. This disclosure details how branched-chain alcohols have unexpectedly demonstrated superior foam control performance. This performance is even better than that of alkoxylated copolymers (polyglycols, both diols and triols as initiators) in foam control, making it possible to utilize these materials as foam control agents in bioethanol fermentation applications. The branched-chain alcohols may be 2-alkyl-1-alkanols (also known as Guerbet alcohols), preferably 2-ethylhexanol (2-EH) and 2-propylheptanol (2-PH). These alcohols can be synthesized via aldol condensation of the corresponding aldehyde or from the Guerbet reaction of primary linear alcohols. Other production methods may also be utilized.

[0008] The general structure of the currently disclosed defoaming agent is as follows:

[0009] [ka] In the formula, x is an integer between 2 and 14, and R is an alkyl group having 1 to 14 carbon atoms.

[0010] The foam control agent may also be described as comprising a C8-C32 2-alkyl-substituted alcohol. The alcohol may be primarily a single isomer (>95% by weight), or a mixture of alcohols which may be produced by aldol condensation of a mixture of aldehydes, or by Guerbet reaction from a mixture of alcohols.

[0011] In some embodiments, C8-C32 Guerbet alcohols containing 2-ethylhexanol and 2-propylheptanol, as well as mixtures of C8, C9, and C10 alcohols produced from the aldol condensation of butyraldehyde and varrealdehyde, are preferred.

[0012] The concentration of Guerbet alcohol in the formulated foam control agent is in the range of 0.01% to 100%, preferably in the range of 40% to 100% when used as an antifoaming agent, and in the range of 0.01% to 25% when used as a defoaming agent. Guerbet alcohol may be in solid or liquid form, with liquid being preferred. If solid, the material may be dissolved or dispersed in a solvent. The foam control agent may be an aqueous solution or an organic solvent solution. The amount of foam control agent used for bioethanol fermentation is in the range of 10 to 10,000 ppm relative to the total amount of liquid present in the fermenter. When used as an antifoaming agent, it is preferably in the range of 50 to 1,000 ppm. When used as a defoaming agent, the dosage is in the range of 10 to 500,000 ppm, preferably in the range of 50 to 10,000 ppm.

[0013] Other foam control agents (e.g., copolymers composed of ethylene oxide, propylene oxide, and / or butylene oxide, which are random copolymers or block copolymers) or other hydrophobic materials such as waxes, oils, or silica may also be added together with the branched-chain Guerbet alcohol(s). Silicones may be used together with 2-alkyl alcohols. Surfactants, particularly alcohol alkoxylates, may also be used. The use of branched-chain alcohols as foam control agents may be aqueous or oil-based.

[0014] The novel foam control agents currently disclosed may be in solid or liquid form. If solid, the material may be dissolved or dispersed in a solvent before use as a foam control agent. The currently disclosed agents are expected to function in the presence of all commonly used bioethanol fermenting yeasts capable of producing foam, including but not limited to different strains such as Saccharomyces Cerevisiae, Candida Albicans, Schizosaccharomyces, and Brettanomyces.

[0015] The chemical agents can be used in both antifoaming and defoaming formulations. Antifoaming formulations are obtained by a mixture of polyglycols, esters, silicones, solvents, water, and other chemicals at the gas-liquid interface of bubbles that prevent foam formation. Other amphiphilic chemicals of block copolymer systems can also be used. In defoaming formulations, in addition to the above products, vegetable oils, mineral oils, waxes, and other oily agents may be used.

[0016] The foam control agents currently disclosed may be used as boosters or main components of such formulations to prevent or break foam. In sugarcane crushers, the above means that the product may be used in the yeast treatment tank or the fermentation tank itself. It can also be used in the processing of sugar beets and potatoes to minimize foam. It may be used continuously or in batches and is very suitable for the operation of any type of crusher.

[0017] This chemical can be added in the tank where the yeast is treated with acid and other chemicals, or in the fermenter before, during, or after the addition of the sugar solution. Fermentation is usually carried out at a temperature below 34°C. This temperature is achieved by using a heat exchanger. After the yeast dispersion is transferred to the fermenter, the sugar solution may be supplied for a considerable time (up to 6 or 8 hours), during which time the greatest effervescence occurs. After the supply of the sugar solution, some additional time may be required to ensure the effective conversion of sugars into ethanol. This additional period can vary from 1 to 4 hours within a total of 12 hours from the start of the sugar solution supply. The current product has been shown to be used throughout the entire fermentation process.

[0018] As described above, the foam control agent may further optionally contain a solvent, a surfactant, an emulsifier, or a combination thereof. In one embodiment, the foam control agent contains 0.01 to 100 weight percent of branched-chain alcohol in the composition. Alternatively, the foam control agent may contain 5 to 100 weight percent of branched-chain alcohol in the composition, 10 to 100 weight percent of branched-chain alcohol in the composition, 15 to 100 weight percent of branched-chain alcohol in the composition, 20 to 100 weight percent of branched-chain alcohol in the composition, 25 to 100 weight percent of branched-chain alcohol in the composition, or 30 to 100 weight percent of branched-chain alcohol in the composition.

[0019] Any solvent contained in the foam control agent is selected to be suitable for dissolving or dispersing the branched-chain alcohol composition. Examples of such solvents include water, hydrocarbons (both aromatic and aliphatic), and oxygenated solvents (alcohols, ketones, aldehydes, ethers, glycol ethers, esters, and glycol ether esters).

[0020] Any surfactant or emulsifier contained in the foam control agent is selected to improve the compatibility of the foam control agent with the raw materials or to be suitable for forming an emulsion with the branched-chain alcohol composition. The surfactant or emulsifier is present in an amount ranging from 0.1 to 30% by weight of the branched-chain alcohol composition.

[0021] Any surfactant or emulsifier may be anionic, cationic, or nonionic. Examples of suitable anionic surfactants or emulsifiers include alkali metals, ammonium, and amine soaps, where the fatty acid portion of such soaps preferably contains at least 10 carbon atoms. Soaps can be formed "in situ," or in other words, by adding fatty acids to the oil phase and alkaline materials to the aqueous phase.

[0022] Other examples of suitable anionic surfactants or emulsifiers include alkali metal salts of alkyl-aryl sulfonic acids, sodium dialkyl sulfosuccinate, sulfated or sulfonated oils, such as sulfated castor oil, sulfonated animal fat, and alkali salts of short-chain petroleum sulfonic acids.

[0023] Suitable cationic surfactants or emulsifiers include salts of long-chain primary, secondary, or tertiary amines such as oleylamide acetate, cetylamine acetate, didodecylamine lactate, aminoethyl-aminoethyl stearamide acetate, dilauroyltriethylenetetramine diacetate, and 1-aminoethyl-2-heptadecenylimidazoline acetate, as well as quaternary salts such as cetylpyridinium bromide, hexadecylethylmorpholinium chloride, and diethyldidodecylammonium chloride.

[0024] Examples of suitable nonionic surfactants or emulsifiers include condensation products of higher fatty alcohols and ethylene oxide, such as the reaction product of oleyl alcohol and 10 ethylene oxide units; condensation products of alkylphenols and ethylene oxide, such as the reaction product of isoctylphenol and 12 ethylene oxide units; condensation products of higher fatty acid amides and 5 or more ethylene oxide units; polyethylene glycol esters of long-chain fatty acids, such as tetraethylene glycol monopalmitate, hexaethylene glycol monolaurate, nonaethylene glycol monostearate, nonaethylene glycol dioleate, tridecaethylene glycol monoarachidate, tricosaethylene glycol monobehenate, tricosaethylene glycol dibehenate; and polyhydric alcohol partial higher fatty acid esters, such as sorbitan tristearate. These include ethylene oxide condensation products of polyhydric alcohol partial higher fatty acid esters, and their intramolecular anhydrides (mannitol anhydride, also known as manitan; sorbitol anhydride, also known as sorbitan), such as glycerol monopalmitate reacted with 10 molecules of ethylene oxide, pentaerythritol monooleate reacted with 12 molecules of ethylene oxide, sorbitan monostearate reacted with 10 to 15 molecules of ethylene oxide, manitan monopalmitate reacted with 10 to 15 molecules of ethylene oxide, and long-chain polyglycols in which one hydroxyl group is esterified with a higher fatty acid and the other hydroxyl groups are etherified with low molecular weight alcohols, such as methoxypolyethylene glycol 550 monostearate (550 represents the average molecular weight of polyglycol ethers). Two or more of these surfactants may be used in combination; for example, a cationic surfactant may be mixed with a nonionic surfactant, or an anionic surfactant may be mixed with a nonionic surfactant.

[0025] The brewing control agent may further contain one or more additives. Examples of the additives include ethylene oxide / propylene oxide block copolymer, butylene oxide / propylene oxide block copolymer, ethylene oxide / butylene oxide block copolymer, wax, or silicone-based material.

Example

[0026] Experiments for testing the effectiveness of the brewing control agent of the present disclosure and the like may be carried out using a fermentation device as follows.

[0027] The chemical substances used as the brewing control agent are commercially available under the trademarks of FLUENT-CANE(™) 149 and FLUENT-CANE(™) 178 from The Dow Chemical Company. 2-Ethylhexanol (2-EH) and 2-propylheptanol (2-PH) were commercially available from Sigma Aldrich.

[0028] The different strains of yeast used were obtained from LNF, a local company in Brazil. For all experiments, a 20 wt% sugar solution was produced with tap water together with 10 wt% yeast (all different strains of Saccharomyces cerevisiae diluted with tap water as well) to obtain 20 degrees Brix (°Bx). The specific different strains of the same yeast (Saccharomyces cerevisiae) used in this study were CAT, PE2, Fermel, and Fleischman. All yeasts were obtained in dry form and needed to be hydrated. To make a better comparison for analysis, semi-finished products without adding the brewing control chemical were also run as controls. Table I provides a list of the strains and brewing control agents used in each example.

[0029] [[ID=​​​​​​​A certain amount (for example, 0.135 g) of foam control agent is added to a mixture of 300 g of yeast preparation and 600 g of sugar solution. In this example, the addition of 0.135 g of foam control agent results in a foam control agent concentration of approximately 150 ppm relative to the total weight of the 900 g of solution added to the fermentation apparatus. Next, the entire mass is transferred to a cylindrical container and air is injected through a porous plate.

[0031] Subsequently, an airflow velocity of 7.0 L / min was passed through a porous plate (pore size 16-40 μm), and the time required for the bubbles to reach a height of 25 cm was measured. This demonstrated the differences in bubble behavior and the ability of each tested agent to maintain bubble height compared to each yeast strain. A longer time to reach bubble height indicates better product performance. This parameter is represented as "Time to reach 25 cm" (T25) in Table 2.

[0032] [Table 2]

[0033] Comparing all yeast strains with all foam control agents, the inventors surprisingly found that controlling the foam produced by the Fleishman strain using 2-propylheptanol and 2-ethylhexanol resulted in higher values ​​for the time to reach 25 cm. This strain is one of those primarily used in sugarcane crushers because its price is much lower than that of other strains. Therefore, the use of such a foam control agent for bioethanol production is highly desirable.

Claims

1. A method for controlling foam for bioethanol treatment using a foam control agent, wherein the foam control agent is It comprises at least one alcohol selected from the group consisting of 2-ethylhexanol and 2-propylheptanol, and A method comprising using Fleischmann strain yeast in the bioethanol treatment described above.

2. The method according to claim 1, wherein at least one other foam control agent or hydrophobic material is added.

3. The method according to claim 1, wherein a silicone or surfactant is also added when processing bioethanol.

4. The method according to claim 1, wherein the bioethanol treatment is carried out in a fermentation tank, and the concentration of the branched-chain alcohol in the fermentation tank is 1 to 500,000 ppm.

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