Fuel oil reclamation method

Abstract

At least one C8-C 2000-4000 sulphuric acid salt for use in the recovery of fuel oil from a fuel-in-water emulsion. 18 Fatty acid diethanolamides, at least one C 12 ~C 24 Fatty acids, at least one C6-C 18 A demulsifier comprising an alcohol ethoxylate is provided, as well as a method for recovering fuel oil from a fuel-oil-in-water emulsion using the demulsifier.

Description

[Technical field]

[0001] The present invention relates to a method for separating emulsified oil waste, particularly heavy oil, from water. [Background technology]

[0002] The present invention relates to a novel method for improving the separation of oil from oil-in-water emulsions, which can be used to separate fuel oil and water emulsions, such as the emulsified fuel oil and water waste from ships, such as those resulting from bilge water and cargo tank washing, commonly known as "ship slops".

[0003] When heated to 65°C, these ship slops separate over approximately 12-24 hours, with approximately 20% of the water remaining as a separate phase. However, ship slops contain a large amount of water, up to 90%, along with only 10% heavy fuel oil (HFO). If the yield of water separated by temperature control alone is only 20%, most of the water is still left behind emulsified with the oil. The more water that remains emulsified with the oil, the lower the value of the recycled oil.

[0004] Conventionally, there are a number of methods to enhance the separation of water-in-oil emulsions, such as chemical demulsification, gravity or centrifugation, membrane separation, filtration, and electrostatic demulsification. Several chemical emulsifiers were used individually by Yau et al. to increase the water removal rate from Mapol oil waste, a mixture of seawater and spent oil ("Evaluation of different demulsifiers for Mapol oil waste recovery"(2017) Journal of water processing engineering 17;40-49). Hajivand & Yaziri described the combined use of water-soluble and oil-soluble emulsifiers to promote separation of water in crude oil emulsions ("Optimization of demulsifier formation for separation of water from crude oil emulsions"(2015) Brazilian Journal of Chemical engineering 32(1);107-118).

[0005] Current commercially available separation techniques necessitate large scale facilities to handle the very large volumes of ship slops generated by ships, and which are typically not loaded at port. It would be advantageous to provide a method that can separate high levels of hydrocarbons from water, without requiring large scale industrial facilities. [Brief description of the drawings]

[0006] [Figure 1] 1 shows the separation of an emulsion into an aqueous (water) phase and an oil phase following the addition of demulsifiers and treatment with ultrasound. The demulsifiers are: (a) oleic acid; (b) dodecylbenzenesulfonic acid; and (c) the demulsifier composition of Example 1. [Figure 2-1] 2 shows the separation of an emulsion into an aqueous (water) phase and an oil phase following the addition of a demulsifier and treatment with ultrasound. The demulsifiers are (a) the demulsifier composition of Example 1; (b) a combination of 1 part by weight of the demulsifier composition of Example 1 and 4 parts by weight of oleic acid. [Figure 2-2](c) 1 part by weight of the demulsifier composition of Example 1 in combination with 4 parts by weight of butyloxytol. [Diagram 3] FIG. 3 shows the processing device. Summary of the Invention

[0007] The present invention relates to the use of demulsifiers to improve such separation and recover up to 95% of the water. High recovery of water from oil emulsions such as ship slops means that the recovered oil has a lower water content and therefore is of higher value when reclaimed. The process of the present invention can be used to recover oil from waste materials generated from a variety of processes such as tank lees, mapol water, bilge water and ship slops.

[0008] For the purposes of the present invention, references to "oil" include fuel oils and industrial oils such as chain oils, hydraulic oils and engine oils. Preferably, the term "oil" does not include crude oil or bitumen. For purposes of this invention, references to "fuel oil" are intended to encompass petroleum diesel, low sulfur diesel, biodiesel and combinations thereof, and heavy fuel oil (HFO). For purposes of this invention, references to "petroleum diesel" relate to diesel produced during the distillation of crude oil. For the purposes of the present invention, reference to "heavy oil" is to an oil produced during the distillation of crude oil and having a density of 900 kg / m at 15°C. 3 More than or equal to is related to. For the purposes of this invention, references to "heavy fuel oil" include Bunker C fuel oil, intermediate fuel oil, and low sulphur marine fuel oil. For purposes of the present invention, reference to "low sulfur diesel" relates to diesel having less than 500 ppm sulfur, preferably less than 50 ppm sulfur, and most preferably less than 10 ppm sulfur. Low sulfur diesel can be produced by removing sulfur from petroleum diesel, by the formation of synthetic diesel, or by the formation of biodiesel. For the purposes of the present invention, reference to "biodiesel" relates to fatty acid methyl esters obtained by transesterification of vegetable oils or animal fats with alcohol, typically methanol or ethanol. For purposes of this invention, references to "bio-components" relate to biodiesel and natural oils such as palm oil, rapeseed oil and coconut oil.

[0009] In a first aspect of the present invention, (i) adding at least 0.01 wt. % of a demulsifier to the oil-in-water emulsion; (ii) dispersing the demulsifier in oil using ultrasonic treatment at 2-50 Ws / g; (iii) separating the oil and aqueous phases; There is provided a method for recovering oil from an oil-in-water emulsion, In the oil recovery method, the demulsifier is At least one C8-C 18 Fatty acid diethanolamides; b. At least one C 12 ~C 24 fatty acids; and c. At least one C6-C 18 Alcohol ethoxylates; Includes.

[0010] Preferably, the oil-in-water emulsion is an oil-in-water emulsion waste. Such emulsions include tank sediments, marpol water, bilge water and ship slops. These emulsion wastes may be generated by washing cargo tanks to remove oily cargo residues or by emptying ballast tanks. Preferably, the oil is a fuel oil. Preferably, the oil recovery process is used to separate emulsions of diesel, low sulfur diesel, biodiesel or heavy oil in water. The oil-in-water emulsion comprises at least 50% v / v water, preferably at least 60% v / v water, at least 70% v / v water, at least 80% v / v water, preferably up to 90% v / v water.

[0011] The oil recovery process can be used to separate water from water-in-oil emulsion waste by first converting the water-in-oil emulsion to an oil-in-water emulsion, and the process may further comprise the steps of: (i1) Adding a quantity of water to form an oil-in-water emulsion containing at least 50% v / v water.

[0012] In practice, it is difficult to quickly determine the water content of a water-in-oil emulsion. Therefore, a simple method for producing an oil-in-water emulsion is to ensure a large excess of water by adding a volume of water equal to or greater than the volume of the emulsion. In a preferred embodiment, the following steps are provided: (i1) Adding a volume of water equal to or greater than the volume of the water-in-oil emulsion. The addition of water causes the emulsion to change in nature to an oil-in-water emulsion. The water can be added prior to the demulsifier or simultaneously with the demulsifier. Preferably, water is added to the emulsion and mixed to form the oil-in-water emulsion before the demulsifier is added.

[0013] Preferably, the demulsifier is used in an amount of 0.01 to 5.0 wt% based on the amount of the oil-in-water emulsion, more preferably, 0.05 to 4.0 wt% based on the amount of the oil-in-water emulsion, 0.1 to 3.5 wt% based on the amount of the oil-in-water emulsion, 0.2-3.0 wt% based on the amount of the oil-in-water emulsion, 0.3 to 2.5 wt% based on the amount of the oil-in-water emulsion, or 0.5 to 2.0 wt% based on the amount of the oil-in-water emulsion. The demulsifier may be used in an amount of at least 0.01 wt%, at least 0.05 wt%, at least 0.075 wt%, at least 0.1 wt%, at least 0.2 wt%, at least 0.25 wt%, at least 0.5 wt%, at least 0.75 wt%, at least 1.0 wt%, at least 1.25 wt%, at least 1.5 wt%, at least 1.75 wt%, at least 2.0 wt%, at least 2.25 wt%, at least 2.5 wt%, at least 2.75 wt%, at least 3.0 wt%, at least 3.5 wt%, at least 4.0 wt%, or at least 5.0 wt%.

[0014] The demulsifier preferably used in the present invention is C 12 ~C 24 It may contain a carboxylic acid. 12 ~C 24 The carboxylic acids may be aliphatic or aromatic, saturated or unsaturated. Suitable carboxylic acids include fatty acids, which may be saturated or unsaturated. Preferably, the demulsifier suitable for use in the present invention is at least one C 12 ~C 24 The demulsifier comprises a fatty acid. Suitable fatty acids include oleic acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, and linoleic acid. Preferably, the demulsifier comprises oleic acid. Preferably, the demulsifier is at least one C8-C 18The fatty acid diethanolamides include fatty acid diethanolamides. The fatty acid diethanolamides are preferably formed from a mixture of fatty acids having 8 to 18 carbon atoms. The fatty acid diethanolamides are particularly preferably derived from natural sources. Suitable natural sources include coconut oil and palm oil. For example, coconut oil is a mixture of acids including caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, and linoleic acid.

[0015] In a particularly preferred embodiment, the demulsifier comprises the following components: At least one C8-C 18 Fatty acid diethanolamides; b. At least one C 12 ~C 24 fatty acids; and c. At least one C6-C 18 Alcohol ethoxylates; d. optionally, at least one sorbitan ester. Preferably, the demulsifier consists essentially of components (a), (b), (c) above, and optionally further consists of component (d) above. If the oil-in-water emulsion contains a biofuel, it is preferred that the demulsifier comprises or consists essentially of components (a), (b), (c) and (d) above. In the present invention, "consists essentially of" means that the composition contains less than 2% by weight, and preferably less than 1% by weight, of other components. Furthermore, compared to currently available older low-sulfur heavy oils, where the amount of sulfur has been reduced to comply with environmental legislation (IMO 2020), resulting in reduced lubricity of the heavy oil and mechanical problems, the use of the above-mentioned demulsifier composition provides lubrication performance benefits and improves the quality of the heavy oil.

[0016] One of the characteristics of the ingredients used in demulsifiers is the HLB. The HLB value can be either calculated or experimentally determined. Standard calculation methods include the Griffin method (Journal of the Society of Cosmetic Chemists 5(1654):259) or the Davies method (Gas / Liquid and Liquid / Liquid interface:Proceedings of the International Congress of the Surface Activity(1657)). However, it is preferred that the HLB value is obtained experimentally. Usually, material suppliers provide experimentally obtained HLB values ​​for their products. Those skilled in the art are aware of suitable methods for determining the HLB value, for example, using comparative tests in which a series of emulsions are used with emulsifiers and oils with known HLB values. In general, HLB values ​​in the range of 3.5 to 6 are commonly used for water-in-oil emulsions. HLB values ​​in the range of 8 to 18 are used for oil-in-water emulsions.

[0017] Coconut oil diethanolamides typically have an HLB range of 13 to 14. Although it is not essential that the diethanolamide have an HLB in this range, it is preferred that the diethanolamide have an HLB in the range of 11 to 16, preferably 13 to 14. Fatty acid diethanolamides based on fatty acids having fewer than 8 or more than 18 carbon atoms may optionally be present in the mixture, but are preferably not present. The fatty acid diethanolamide is preferably present in an amount of 40 to 90% by weight of the demulsifier, more preferably 50 to 90% by weight, and even more preferably 60 to 85% by weight.

[0018] At least one C 12 ~C 24 The fatty acid is preferably saturated or monounsaturated, more preferably monounsaturated. 14 ~C 20A particularly preferred fatty acid is oleic acid. Oleic acid has an HLB of about 1. A low HLB means high lipophilicity, and therefore this lipophilic material is not usually used as a demulsifier. The fatty acid preferably has a low HLB, preferably less than 3.5, more preferably less than 2. The fatty acid is preferably present in an amount of from 1 to 15% by weight of the demulsifier, more preferably from 2 to 10% by weight, and most preferably from 4 to 7% by weight.

[0019] C6~C 18 The alcohol ethoxylates are preferably produced from at least one alcohol, more preferably at least one monol. The ethoxylates preferably have 2 to 8 ethoxy groups. Preferred ethoxylates are nonylphenol ethoxylates and C9 to C 12 Suitable ethoxylates include Berol 260 and Ethylan 1005, narrow range ethoxylated alcohols available from AkzoNobel. The range of HLB values ​​that nonylphenol ethoxylates have depends on the number of ethylene oxide groups present. Preferred nonylphenol ethoxylates have 4 to 8 ethylene oxide groups and have an HLB of about 9 to 12. Particularly preferred nonylphenol ethoxylates have 6 ethylene oxide groups and an HLB of about 11. Berol 260 has an HLB value of 10.5 and is a narrow range C9-C olefin with four ethylene oxide groups. 11 Ethylan 1005 has an HLB value of 11.6 and is a narrow-range C alcohol with 3.5 ethylene oxide groups. 10 It's alcohol. The alcohol ethoxylates preferably have an HLB value in the range of 9-12, preferably 10-12. Preferably, the alcohol ethoxylate is present in an amount of 5 to 30% by weight of the demulsifier, more preferably, the alcohol ethoxylate is present in an amount of 5 to 20% by weight, and even more preferably, the alcohol ethoxylate is present in an amount of 8 to 12% by weight.

[0020] Sorbitan esters are the reaction products of sorbitan with one or more carboxylic acids. Preferably, the carboxylic acid has 8 to 22 carbon atoms. Preferably, the carboxylic acid has 8 to 22 carbon atoms, which is the carbon chain length found in naturally occurring fatty acids in triglycerides. Particularly preferred are carboxylic acids having 16 to 22 carbon atoms, and even more preferred are carboxylic acids having 18 carbon atoms. The fatty acids can be both linear and branched. Both saturated and unsaturated fatty acids are suitable, however, unsaturated fatty acids are preferred. Sorbitan esters suitable for use in the present invention include the following:

[0021] [Table 1]

[0022] Suitable sorbitan esters have an HLB of less than 6.0. Preferred sorbitan esters are those having an HLB of 3 to 5. Particularly preferred is sorbitan monooleate.

[0023] Particularly preferred demulsifiers may include the following components: a. 50-90% by weight of at least one C8-C 18 Fatty acid diethanolamides; b. 2 to 10% by weight of at least one C 12 ~C 24 fatty acid; c. 5 to 20% by weight of at least one C6 to C 18 an alcohol ethoxylate; and optionally d. 10-40% by weight of at least one sorbitan ester. Preferred components a to d are as described above.

[0024] In a preferred embodiment, the demulsifier comprises 80-90 wt. % of component a, 4-8 wt. % of component b, and 5-15 wt. % of component c, or consists essentially of components a, b and c in the amounts stated above. In a further preferred embodiment, the demulsifier comprises 55-65 wt.% of component a, 4-8 wt.% of component b, 5-15 wt.% of component c, and 20-30 wt.% of component d, or consists essentially of components a, b, c and d in the amounts recited above. The demulsifiers of the present invention advantageously enhance the recovery of oil from oil-in-water emulsions, and are environmentally beneficial since they can be manufactured using naturally derived materials and therefore typically do not contain ingredients that are harmful during manufacture.

[0025] The demulsifier contains at least one C 12 ~C 24 It can be added to the emulsion together with the fatty acid or alkylene glycol monoalkyl ether. Preferably, 1 part of the demulsifier is added together with 5 to 10 parts of the fatty acid or alkylene glycol monoalkyl ether.

[0026] At least one C 12 ~C 24 The fatty acid is preferably saturated or monounsaturated, more preferably monounsaturated. 14 ~C 20 At least one C monounsaturated fatty acid is used to dilute the demulsifier. 12 ~C 24 The fatty acid has at least one C 12 ~C 24 The fatty acid may be the same or different, a particularly preferred fatty acid being oleic acid. The combined demulsifier and fatty acid composition added to the emulsion may include the following components: a. 10-20% by weight of at least one C8-C18 Fatty acid diethanolamides; b. 75 to 85% by weight of at least one C 12 ~C 24 fatty acid; c. 0.5 to 5% by weight of at least one C6 to C 18 an alcohol ethoxylate; and optionally d. 2-8% by weight of at least one sorbitan ester.

[0027] Preferably, the combination composition consists essentially of the above components (a), (b), and (c), and optionally further consists of the above component (d). Preferred components (a) to (d) are as described above.

[0028] Alternatively, the combined demulsifier and alkylene glycol monoalkyl ether composition added to the emulsion may comprise the following components: a. 10-18% by weight of at least one C8-C 18 Fatty acid diethanolamides; b. 0.4 to 2.0% by weight of at least one C 12 ~C 24 fatty acid; c. 0.5 to 5% by weight of at least one C6 to C 18 Alcohol ethoxylates; d. 67.0 to 89.1 wt. % of at least one alkylene glycol monoalkyl ether; and optionally, e. 2-8% by weight of at least one sorbitan ester.

[0029] Preferably, the diluted demulsifier consists essentially of components (a), (b), (c), (d) above, and optionally further consists of component (e) above. Preferred components (a) to (c) and (e) are as described above. The alkylene glycol monoalkyl ether is preferably an ethylene glycol monoalkyl ether, more preferably an ethylene glycol monoalkyl ether having an alkyl group having 1 to 6 carbon atoms, and more preferably, the ether is 2-butoxyethanol (butyloxytol). The alkylene glycol monoalkyl ether is used in an amount of preferably 67.0 to 89.1% by weight, more preferably 68.5 to 83.5% by weight, and further more preferably 70 to 80% by weight.

[0030] Preferably, the present invention provides a method for recovering oil from an oil-in-water emulsion comprising the following steps: (i) adding 0.01 to 4.0% by weight of a demulsifier to the oil-in-water emulsion, wherein the demulsifier comprises: At least one C8-C 18 Fatty acid diethanolamides; b. At least one C 12 ~C 24 fatty acids; and c. At least one C6-C 18 an alcohol ethoxylate; and optionally d. at least one sorbitan ester. (ii) The demulsifier is dispersed in the oil using ultrasonic treatment at 2-50 Ws / g.

[0031] In another aspect, the present invention provides a method for recovering oil from oil-in-water emulsion waste comprising the steps of: (i) adding at least 0.01% by weight of a demulsifier to the oil-in-water emulsion waste material; (ii) The demulsifier is dispersed in the oil using ultrasonic treatment at 2-50 Ws / g. (iii) separating the oil and water phases; Here, the demulsifier is C 12 ~C 24 Carboxylic acid or sulfonic acid, or C8-C 18 Contains fatty acid diethanolamides.

[0032] In this respect, the demulsifier preferably used is C 12 ~C 24 Contains carboxylic or sulfonic acids or mixtures thereof. 12 ~C 24 The carboxylic or sulfonic acids may be aliphatic or aromatic, saturated or unsaturated. Suitable carboxylic acids include fatty acids, which may be saturated or unsaturated as described above. As used herein, a "sulfonic acid" has the formula RS(=O)2-OH, where R is C 12 ~C 24 R is an alkyl or aryl group, or a combination thereof, for example, an alkylaryl group. "Alkyl" is a branched, straight-chain or cyclic saturated hydrocarbon group containing from 1 to 24 carbon atoms. Alkyl preferably contains from 6 to 20 carbon atoms, more preferably from 12 to 18 carbon atoms. An "aryl" group is an aromatic monocyclic or bicyclic ring structure of five to eighteen ring atoms. Examples of aryl include phenyl, biphenyl, and naphthyl. Suitable sulfonic acids include dodecylbenzenesulfonic acid and decylbenzenesulfonic acid. Preferably, the demulsifier comprises dodecylbenzenesulfonic acid.

[0033] The demulsifier comprises or consists essentially of oleic acid or a sulfonic acid (preferably dodecylbenzenesulfonic acid). In this respect, the demulsifier comprises at least 80% by weight, preferably at least 85% by weight, at least 90% by weight, at least 95% by weight, at least 97% by weight, or at least 99% by weight of oleic acid or sulfonic acid.

[0034] Preferably the demulsifier is similar to those described for use in the oil recovery process of the first aspect. Preferably, the demulsifier comprises oleic acid. Preferably, the demulsifier comprises the following components: At least one C8-C 18 Fatty acid diethanolamides; b. At least one C 12 ~C 24 fatty acids; and c. At least one C6-C 18 Alcohol ethoxylates; d. optionally, at least one sorbitan ester. Preferably, the demulsifier consists essentially of components (a), (b) and (c) above, and optionally further consists of component (d) above. Preferably, the fatty acid diethanolamide is derived from coconut oil diethanolamide. Preferably, the alcohol ethoxylate is a nonylphenol ethoxylate.

[0035] The addition of a demulsifier breaks the emulsion and separates the water and oil phases. The efficiency of the separation process depends on the amount of demulsifier present, the degree of mixing of the emulsion with the demulsifier, and the temperature of the emulsion. Ultrasonic power is an effective and energy-efficient means to impart high shear and intense stress to liquids, powder / liquid mixtures and slurries. It is a powerful alternative to high shear mixers, high pressure homogenizers and other large scale mixing formats. Sonication is used to agitate mixtures with the goal of creating fine dispersions. One of the benefits of using sonication to agitate emulsions is the speed at which the emulsion is broken down into oil and water. Emulsions can be broken down in minutes rather than hours. The amount of water recovered from the emulsion is also increased.

[0036] Ultrasonic application is described using the term "Ws / g". It is the power (W) applied per second (s) per amount expressed in grams (g) or volume (mL) of material to be sonicated. Every method has an optimum specific energy (Ws) per mL, which differs from method to method. If too little specific energy is used, the method will be incomplete. But if the specific energy is too high, it will waste time and energy and may damage the equipment. The optimum Ws / g, depending on the ratio of water to oil to be separated, has been determined to be between 2 and 50 Ws / g, preferably between 5 and 30 Ws / g. Higher specific energies, for example reaching 250 Ws / g, can be used, but as mentioned above, this would waste time and energy since separation can be achieved in the same time using lower energy levels. Preferably, Ws / g is in the range of 7 to 20 Ws / g, more preferably in the range of 8 to 17 Ws / g, even more preferably in the range of 10 to 15 Ws / g.

[0037] Alternatively, the specific energy required can be measured as power (W) applied per second (s) per mL of volume. This may simplify the calculation, especially since the specific gravity of oil-in-water emulsions can vary. The specific gravity of oil-in-water emulsions separated by the method of the present invention is typically 0.8-0.98 g / mL. Thus, 1 Ws / g is equivalent to 0.8-0.98 Ws / g. Heavy oil has a specific gravity of about 1.0. The optimum Ws / ml, depending on the ratio of water to oil to be separated, has been determined to be between 2 and 62.5 Ws / ml, preferably between 5.1 and 37.5 Ws / ml. Higher specific energies can be used, for example reaching 255 Ws / ml, but as mentioned above this would waste time and energy since separation can be achieved in the same time using lower energy levels. Preferably, Ws / ml is in the range of 7.1 to 25 Ws / ml, more preferably in the range of 8.1 to 21.25 Ws / ml, even more preferably in the range of 10.2 to 18.75 Ws / ml.

[0038] Increasing the total power often means less time is required to sonicate a given volume. Conversely, increasing the material volume, i.e., scaling up, means more time or additional power is required to maintain the optimum Ws / g. The specific energy required to break an emulsion may also depend on the concentration of demulsifier present. If a small amount of demulsifier is used, a high specific energy is required. If a larger amount of demulsifier is used, less specific energy is required. Preferably, the demulsifier is present in an amount that is at least 0.2% by weight based on the amount of oil-in-water emulsion and the specific energy is at least 10 Ws / g or 10.2 Ws / ml. More preferably, the demulsifier is present in an amount that is at least 0.25% by weight based on the amount of oil-in-water emulsion and the specific energy is at least 7.5 Ws / g or 7.65 Ws / ml; or, the demulsifier is present in an amount that is at least 0.5% by weight based on the amount of oil-in-water emulsion and the specific energy is at least 5.0 Ws / g or 5.10 Ws / ml.

[0039] The demulsification process is typically carried out at temperatures between 25 and 80°C, preferably between 55 and 70°C, and more preferably at about 65°C. The demulsification process is typically carried out at a pH of 4 to 7, preferably at pH 5.5.

[0040] Once the emulsion has been broken, the water and oil can be separated by conventional techniques, including, for example, centrifugation or gravity separation. For example, the emulsion can be clarified by gravity and the water / aqueous phase can be withdrawn. The withdrawn water can be further treated, as required, by pH adjustment, filtration, and membrane separation to further reduce the oil content. Ideally, once the amount of oil in the water has been reduced to 15 ppm or less, it is no longer considered "contaminated water" and can be safely and legally discharged overboard or into the sea. Typically, the broken emulsion separates under gravity. After mixing the demulsifier with the oil-in-water emulsion, separation begins immediately. The time required to complete separation of the water and oil phases may vary depending on the concentration of the demulsifier used, the specific energy added, and the temperature. Preferably, separation is complete after 24 hours or less. Preferably, phase separation can occur after 24 hours. Preferably, phase separation can occur after 12 hours, 6 hours, 5 hours, 4 hours, 2 hours, or 1 hour. However, in some situations, such as when there is a large storage facility, separation times longer than 24 hours may be used. The water content in the separated oil is preferably less than 10% v / v, more preferably less than 5% v / v, less than 2.5% v / v, and most preferably less than 1% v / v.

[0041] In another aspect, the present invention provides a method for removing water from an oil-in-water emulsion, comprising the steps of: (a) a separating means having an inlet; (b) optionally, a means for introducing a demulsifier; and (c) a sonicator in fluid communication with the separating means; An apparatus having the steps of: The separation means is a device for separating the water and oil phases of an oil-in-water emulsion when the emulsion is broken by the addition of a demulsifier. The separation means may be a centrifuge or a clarifying tank. A demulsifier is added to the oil-in-water emulsion and the mixture is passed through an ultrasonicator to ensure complete mixing. After sonication, the mixture is transferred to a separation means to complete the separation of the aqueous and oil phases.

[0042] In a preferred embodiment, the device comprises: (a) a clarification tank having an inlet and a first outlet disposed at a bottom of the clarification tank; (b) optionally, a means for introducing a demulsifier; (c) a sonicator in fluid communication with the separating means; The ultrasonic processor, together with the clarification tank, forms a closed circuit.

[0043] The demulsifier is preferably the demulsifier described above. The inlet is controlled by a valve to allow the oil-in-water emulsion to enter the tank, and is preferably located close to the top of the tank. The first outlet is located at the bottom of the tank and allows the contents of the tank to be withdrawn. The first outlet may be located at the bottom of the separation tank or may be through the side wall of the tank near the bottom. Once the emulsion is broken and the oil and water separate, the separated phases can be withdrawn. Both the water phase and the oil phase may be withdrawn through the same outlet. Alternatively, a second outlet may be provided, with the water phase being removed through one outlet and the oil phase being removed through the other outlet. Each outlet is controlled by a valve.

[0044] The clarification tank is in fluid communication with the sonicator, which forms a closed loop with the clarifier. The oil-in-water emulsion waste is passed through the sonicator together with the demulsifier to mix the demulsifier with the emulsion. Once the emulsion / demulsifier has been sonicated, the mixture is returned to the clarification tank. The contents of the clarification tank may be pumped to the sonicator or returned to the clarification tank. The contents of the clarification tank may be passed through the sonicator one or more times. This is to ensure sufficient mixing of the demulsifier with the emulsion so that clarification can occur within one hour of the onset of phase separation. The number of passes through the sonicator will depend on several factors, including the flow rate and the power of the sonicator. The contents of the clarification tank need to be exposed to sufficient specific energy to effect efficient separation. As mentioned above, this is typically 2-50 Ws / g or 2-62.5 Ws / ml. Prior to clarification of the contents of the clarification tank, the contents are passed through a sonicator preferably in the range of 1-5 times, more preferably 1-3 times.

[0045] The demulsifier may be added to the oil-in-water emulsion before it enters the clarification tank. Alternatively, the demulsifier may be added to the oil-in-water emulsion in the clarification tank. The clarification tank may have a separate valve-controlled inlet for adding the demulsifier, or the demulsifier may be added through the same inlet as the oil-in-water emulsion. Alternatively, the demulsifier may be added to the oil-in-water emulsion as it passes from the clarification tank to the sonicator. The connection between the clarification tank and the sonicator may have a valve-controlled inlet to allow the demulsifier to be fed to the oil-in-water emulsion. Preferably, the demulsifier is added at or just before the emulsion enters the sonicator or to the pump, if present, used to transfer the emulsion to the sonicator.

[0046] Suitable ultrasonicators include industrial ultrasonic transducers, such as those designed to aid in transesterification reactions in biodiesel production, such as those manufactured by Hieslscher Ultasound GmbH. These include sonotrodes and cascatrodes. More than one ultrasonicator can be used. Multiple devices arranged in series can be used to increase throughput. Alternatively, a single larger device can be used to accommodate the processes required to process the same amount in the same amount of time.

[0047] In another aspect, the present invention provides a method for removing water from an oil-in-water emulsion waste, comprising the steps of: (a) a holding tank having an inlet and an outlet, and optionally having a means for introducing a demulsifier; (b) a sonicator in fluid communication with the holding tank; (c) separation means; An apparatus having the steps of: The separation means is a device for separating the water and oil phases of an oil-in-water emulsion when the emulsion is broken by the addition of a demulsifier. The separation means may be a centrifuge or a clarifying tank.

[0048] In a preferred embodiment, the device comprises: (a) a holding tank having an inlet and an outlet, and optionally having a means for introducing a demulsifier; (b) a sonicator in fluid communication with the holding tank; (c) a clarification tank in fluid communication with the sonicator; the clarification tank having an inlet and an outlet disposed at a bottom of the clarification tank. The emulsion to be broken, e.g., ship slop, can be stored in a holding tank (1). If the emulsion is a water-in-oil emulsion, it can be converted to an oil-in-water emulsion by adding at least the same volume of water as the emulsion. The emulsion is transferred to the flow cell of the sonicator (4). The flow rate can be controlled by a pump (2) and / or a valve (3).

[0049] The demulsifier is added to the emulsion. The demulsifier can be added to the emulsion in the holding tank (1). The holding tank (1) may have a separate valve-controlled inlet for adding the demulsifier. The demulsifier may be added through the same inlet as the emulsion. As a further alternative, the demulsifier may be added to the oil-in-water emulsion as it passes from the holding tank to the sonicator (4). The connection between the holding tank and the sonicator may have a valve-controlled inlet to allow the demulsifier to be fed to the oil-in-water emulsion. Preferably, the demulsifier is added at or just before the emulsion enters the sonicator or, if present, to a pump that transfers the emulsion to the sonicator. The oil-in-water emulsion is passed through a sonicator together with a demulsifier, which mixes the demulsifier with the emulsion. Once the emulsion / demulsifier has been sonicated, if set for a single pass, the mixture is transferred to a clarification tank (7) where the water and oil phases are separated. The flow to the clarification tank can be controlled by a valve (5).

[0050] The mixed emulsion / demulsifier is sonicated for one or more revolutions before being clarified in a clarification tank. The mixed emulsion / demulsifier may optionally be recirculated or transferred back to the holding tank (1) or directly to the sonicator flow cell (4) before being sonicated for more revolutions. Flow into the holding tank (1) may be controlled by valve (6). Optional flow paths are shown in Figure 3 with dashed lines. Once the emulsion / demulsifier is thoroughly mixed by sonication, the mixture is transferred to a clarification tank for clarification.

[0051] Alternatively, the mixed emulsion / demulsifier may be returned to the sonicator for more rounds of sonication before being transferred to a clarification tank and then clarified. Preferred features of the clarification tank are as described above. Preferred characteristics of the demulsifier are as described above.

[0052] In another aspect of the present invention, there is provided a use of a demulsifier for recovering oil from an oil-in-water emulsion waste, the demulsifier comprising: At least one C8-C 18 Fatty acid diethanolamides; b. At least one C 12 ~C 24 fatty acids; and At least one C6-C 18 an alcohol ethoxylate; and optionally c. at least one sorbitan ester The demulsifier here is used in an amount of at least 0.01% by weight, based on the amount of emulsion. Preferred characteristics of the demulsifier are as described above.

[0053] In another aspect of the invention, there is provided a composition comprising an oil-in-water emulsion: wherein the emulsion comprises at least 50% by weight of water and at least 0.01% by weight of a demulsifier, the demulsifier comprising: At least one C8-C 18 Fatty acid diethanolamides; b. At least one C 12 ~C 24 fatty acid; c. At least one C6-C 18 an alcohol ethoxylate; and optionally d. at least one sorbitan ester. Preferred components (a) to (d) are as described above.

[0054] In another aspect, there is provided a composition comprising an oil-in-water emulsion waste product: The emulsion herein comprises at least 50% by weight water and at least 0.01% by weight of a demulsifier. The demulsifier comprises or consists essentially of oleic acid or sulfonic acid.

[0055] The invention will be further explained with reference to the following figures. 1 shows the separation of an emulsion into an aqueous (water) phase and an oil phase following the addition of demulsifiers and treatment with ultrasound. The demulsifiers are: (a) oleic acid; (b) dodecylbenzenesulfonic acid; and (c) the demulsifier composition of Example 1. 2 shows the separation of an emulsion into an aqueous (water) phase and an oil phase following the addition of demulsifiers and treatment with ultrasound. The demulsifiers are (a) the demulsifier composition of Example 1; (b) a combination of 1 part by weight of the demulsifier composition of Example 1 and 4 parts by weight of oleic acid, and (c) a combination of 1 part by weight of the demulsifier composition of Example 1 and 4 parts by weight of butyloxytol. FIG. 3 shows the processing device. The invention will now be further described with reference to the following examples. EXAMPLES

[0056] Working Example A demulsifier composition was prepared containing the following components: 85% v / v Coconut Fatty Acid Diethanolamide (SABO®) 5% v / v oleic acid (NuVest) 10%v / v nonylphenol polyethoxylate

[0057] <Emulsion> Ship slops were obtained from an oil waste processor. To collect ship slops from large vessels, samples were taken from used tankers.

[0058] <Test> The test was carried out using a modified bottle test. The same volume of emulsion to be broken was placed in a series of tubes and demulsifier was added to each tube. The demulsifier was added to the samples and they were sonicated at 65°C with a 22mm sonotrode (UP400St Hielscher Ultrasound Technology 400W, 24kHz) at maximum amplitude, 150W. The separation of the layers was monitored by the position of the water / emulsion interface and the volume of water separated was recorded.

[0059] [Example 1] A 2% v / v demulsifier composition was added to 500 ml of ship slop (500 g) and sonicated for 100 seconds, adding approximately 30 Ws / g. The contents of the tube were then clarified. The results are shown in Table 1.

[0060] [Table 2]

[0061] <Result> After clarification, the water phase was measured to be 80 mm out of a total height of 150 mm, therefore the original sample contained approximately 54% water. The water content in the oil was determined and found to be 0%.

[0062] [Example 2] The compositions were tested to determine the amount of demulsifier required to break the emulsion. 100 ml of ship slop was weighed and mixed with the amount of demulsifier composition shown in Table 2. The mass was 100 g. The emulsion / demulsifier mixture was sonicated for 150 seconds at 65° C., 150 W, maximum amplitude, using a 22 mm sonotrode. This added approximately 225 Ws / g. The separation of the layers was monitored by the position of the water / emulsion interface and the volume of water separated was recorded. The results are shown in Table 2.

[0063] [Table 3]

[0064] After clarification, all samples had a total height of 34mm with the water phase measuring 18mm. The water in oil was determined and found to be 0%. Thus, a measurement of 18 / 34mm water indicates complete separation of the emulsion. This result indicates that a demulsifier composition of around 0.25% v / v is sufficient to destabilize the emulsion and achieve complete separation.

[0065] [Example 3] The amount of ultrasound required to break the emulsion was investigated. 0.25% v / v demulsifier composition was added to 100 ml of ship slop (100 g) and sonicated at 65° C. with a 22 mm sonotrode at maximum amplitude, 150 W. The length of sonication was varied as shown in Table 3. The contents of the tubes were allowed to clarify for 24 hours. The separation of the layers was monitored by the position of the water / emulsion interface and the volume of separated water was recorded (mm water / mm total height). The results are shown in Table 3.

[0066] [Table 4]

[0067] After clarification, the aqueous phase readings changed in less than 5 seconds. To reasonably achieve complete separation within 24 hours, the emulsion / demulsifier mixture required exposures of 7.5 Ws / g or greater by sonicating for at least 5 seconds using the power settings exemplified. Complete separation of samples was observed after longer setting times.

[0068] [Example 4] 100 ml of the ship slop was weighed and mixed with the amount of demulsifier composition shown in Table 4. The mass of the untreated ship slop was 100 g. The emulsion / demulsifier mixture was sonicated using a 22 mm sonotrode at maximum amplitude, 150 W, at the temperature and for the time shown in Table 4. The separation of the layers was monitored by the position of the water / emulsion interface and the amount of separated water after 24 h was recorded (mm water / mm total height). The results are shown in Table 4.

[0069] [Table 5]

[0070] The samples that were not treated with either demulsifier or ultrasound had a uniform black, unseparated appearance. The remaining other samples had areas that looked muddy relative to the water phase. The muddy areas and water phase greater than 18mm indicate the presence of contamination and oil. Thus, separation is not complete. However, if the samples were allowed to clarify for a longer period, complete separation occurred. Test results show that by reducing the amount of demulsifier present or by lowering the temperature, the efficiency of the separation decreases.

[0071] [Example 5] 100 ml of ship slop was weighed and mixed with 0.25% v / v demulsifier composition, oleic acid or dodecylbenzene sulfonic acid. The mass of the untreated ship slop was 100 g. The emulsion / demulsifier mixture was sonicated for 5 seconds at maximum amplitude, 150 W, and 65°C using a 22 mm sonotrode. This added approximately 7.5 Ws / g. The sample was then clarified. After 24 hours, all samples had separated into aqueous and oil phases, as shown in Figure 1. The resulting aqueous phase height was the same, indicating that all three demulsifiers were comparable in effectiveness. It is expected that this method will allow for higher levels of water to be recovered while reducing the time required for separation. Those skilled in the art will be able to purify specific amounts of composition and water.

[0072] [Example 6] One part of the demulsifier composition was mixed with 4 parts by weight of oleic acid or butyloxytol. 100 ml of ship slop was weighed and mixed with 0.25% v / v demulsifier composition or with demulsifier composition additionally containing oleic acid or butyloxytol as shown in Table 5. The untreated ship slop had a mass of 100 g. The emulsion / demulsifier mixture was sonicated for 5 seconds with a 22 mm sonotrode at maximum amplitude, 150 W at 65°C. This added approximately 7.5 Ws / g. The samples were then clarified. As shown in Figure 2, after 1 hour, the samples mixed with the demulsifier composition or the demulsifier composition plus oleic acid formed clearly separate phases. After 24 hours, all samples had separated into water and oil phases. The resulting height of the water phase was the same, indicating that all three demulsifiers were comparable in effectiveness.

[0073] [Table 6]

[0074] [Example 7] Pilot factory A pilot plant was built to process large volumes of oil-in-water emulsions. The collection tank (capacity 35-50 L) was connected to the flow cell of an ultrasonic transducer (UIP1000hdT (1000 W, 20 kHz), supplied by Hielscher Ultrasonics). The outlet of the flow cell was either connected to the collection tank to form a return circuit or to a separate clarification tank. One or more valves were installed in the connecting piping to control the fluid flow. A positive displacement pump was used to transfer the fluid from the collection tank to the flow cell. Typically, ultrasonic transducers can process in the vicinity of 0.5-4.0 liters / min, depending on the amplitude and power required to process the emulsion. A collection tank was first filled with one load of ship slop. A 0.25% v / v demulsifier composition was added to approximately 5L of ship slop in the collection tank. The emulsion / demulsifier mixture was then pumped into the ultrasonic transducer flow cell and sonicated at 7.5 Ws / g before being transferred to a clarification tank. After 24 hours, the ship slop had separated into aqueous and oil phases. Test results were similar to those of the processed examples above.

[0075] In this specification, unless otherwise specified, the word "or" is used in the sense of an operator that returns a value of true if either or both of the specified conditions are met, as opposed to the operator "exclusive or" which requires that only one of the conditions be met. The word "comprising" is used in the sense of "including" and not "consisting of." All prior teachings acknowledged above are incorporated herein by reference. Any admission of a previously published document made herein should not be taken as an admission or representation that the teachings were common general knowledge in Australia or anywhere else at the date hereof.

Claims

1. step (i) adding at least 0.01 wt. % of a demulsifier to an oil-in-water emulsion; step (ii) dispersing the demulsifier in oil using ultrasonic treatment at 2-50 Ws / g; Step (iii) separating the oil and water phases; 1. A method for recovering oil from an oil-in-water emulsion by: The demulsifier is a. At least one C ８ ~C １８ fatty acid diethanolamides; b. At least one C １２ ~C ２４ fatty acid; c. At least one C ６ ~C １８ an alcohol ethoxylate; and optionally, d. at least one sorbitan ester; 10. A method for recovering oil, comprising:

2. The oil recovery method of claim 1 , wherein the oil is fuel oil.

3. 2. The oil recovery method of claim 1, wherein 0.05 to 4.0 wt. % of a demulsifier is added to the oil-in-water emulsion.

4. The oil recovery method of claim 1 , wherein the demulsifier comprises oleic acid.

5. The demulsifier is a. 50 to 90 wt. % of at least one C ８ ~C １８ fatty acid diethanolamides; b. 2 to 10 wt. % of at least one C １２ ~C ２４ fatty acid; c. 5 to 20 wt. % of at least one C ６ ~C １８ an alcohol ethoxylate; and optionally, d. 10 to 40% by weight of at least one sorbitan ester; 2. The oil recovery method of claim 1, comprising:

6. The oil recovery method according to claim 1, wherein the ultrasonic treatment is carried out at 2 to 15 Ws / g.

7. 2. The method for recovering oil according to claim 1, further comprising, in step (i1), converting the water-in-oil emulsion into an oil-in-water emulsion by adding a volume of water equal to or greater than the volume of the water-in-oil emulsion before or simultaneously with step (i).

8. The demulsifier may be a mixture of at least one further C １２ ~C ２４ The oil recovery method according to claim 1, wherein the oil is added together with a fatty acid and / or an alkylene glycol monoalkyl ether.

9. At least one additional C １２ ~C ２４ 9. The method for recovering oil according to claim 8, wherein the ratio of the demulsifier to the fatty acid and / or alkylene glycol monoalkyl ether is 1 part demulsifier: 5 to 10 parts further fatty acid and / or alkylene glycol monoalkyl ether.

10. A demulsifier and at least one further C １２ ~C ２４ The oil recovery method according to claim 8, wherein the total amount of the fatty acid and / or alkylene glycol monoalkyl ether is 0.25 to 20.0% by weight.

11. 11. An apparatus for removing water from an oil-in-water emulsion according to the method of any one of claims 1 to 10, comprising: (a) a separating means having an inlet and containing therein a demulsifier comprising: a. At least one C ８ ~C １８ fatty acid diethanolamides; b. At least one C １２ ~C ２４ fatty acid; c. At least one C ６ ~C １８ an alcohol ethoxylate; and optionally, d. at least one sorbitan ester; (b) optionally, a means for introducing said demulsifier; (c) a sonicator in fluid communication with said separating means; A water removal device comprising:

12. (a) a clarifier tank having an inlet and an outlet, the outlet being located near a bottom of the clarifier tank; (b) a means for introducing a demulsifier; (c) a sonicator in fluid communication with the clarification tank; and 12. The water removal device of claim 11, wherein the ultrasonic processor forms a closed circuit with a clarification tank.

13. 11. An apparatus for removing water from an oil-in-water emulsion according to the method of any one of claims 1 to 10, comprising: (a) a holding tank containing an oil-in-water emulsion having an inlet and an outlet and, optionally, a means for introducing a demulsifier; (b) a sonicator in fluid communication with the holding tank; (c) a separator containing therein a demulsifier comprising: a. At least one C ８ ~C １８ fatty acid diethanolamides; b. At least one C １２ ~C ２４ fatty acid; c. At least one C ６ ~C １８ an alcohol ethoxylate; and optionally, d. at least one sorbitan ester; A water removal device comprising:

14. the separator is a clarification tank in fluid communication with the sonicator; 14. The water removal apparatus of claim 13, wherein the clarifying tank has an inlet and an outlet, the outlet being located near a bottom of the clarifying tank.

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