Biodiesel preparation system suitable for kitchen oil

Abstract

The invention discloses a biodiesel preparation system suitable for kitchen oil. The system comprises a crude oil tank for receiving crude oil subjected to water removal and impurity removal by a pretreatment system, an esterification kettle connected to a discharge port of the crude oil tank, an ester exchange reaction kettle connected to a discharge port of the esterification kettle, and a rectification cutting tower connected to a discharge port of the ester exchange reaction kettle, wherein a settling tank group and a first layering tank are also arranged between the esterification kettleand the ester exchange reaction kettle so as to separate an acidic ionic liquid catalyst from esters; a discharge port at the lower part of the first layering tank is connected with an ionic liquid recovery tank, a discharge port at the upper part of the first layering tank is connected with a feed port of the ester exchange reaction kettle; a crude methyl ester settling tank, a second layering tank and a deodorization tower are further connected between the ester exchange reaction kettle and the rectification cutting tower, and a discharge port of the deodorization tower is connected to a feed port of the rectification cutting tower. Acid sludge cannot be generated, the subsequent treatment difficulty is greatly reduced, and the recyclable rate of the catalyst is high.

Description

Technical field [0001] The invention relates to the technical field of oil production, in particular to a biodiesel production system suitable for cooking oil. Background technique [0002] General kitchen waste oils include kitchen waste oil, slop oil, and waste oil. These waste oils will be pre-processed to remove water and impurities after being recycled to produce biodiesel. However, waste oils are currently used to produce biodiesel In production, in the esterification reaction and transesterification reaction stage, the traditional homogeneous catalyst is generally used as the catalyst, that is, the homogeneous acid-base catalyst is used for the catalytic reaction. However, in the acid-base method as the catalyst reaction process, due to the esterification reaction The transesterification reaction is a reversible reaction. Excess methanol must be added for the reaction. The demand for methanol is particularly large, which will waste methanol. At the same time, the acid in t...

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Problems solved by technology

[0002] Kitchen waste oils in general life include kitchen waste oil, hogwash and gutter oil. After recycling, these waste oils will be pretreated to remove water and impurities before being used to produce biodiesel. However, waste oil is currently used to produce biodiesel. In production, traditional homogeneous catalysts are generally used as catalysts in the stages of esterification and transesterification reactions, that is, homogeneous acid-base catalysts are used for catalytic reactions, but in the process of acid-base reactions as catalysts, due to the esterification reaction The transesterification reaction is a reversible reaction, and an excessive amount of methanol must be added for the reaction. The demand for methanol is particularly large, which will cause waste of methanol; at the same time, the acid in the acid-base method generally uses concentrated sulfuric acid, and the alkali uses sodium hydroxide. Waste oil generally cannot remove various metal ions contained in the oil during the pretreatment stage, so the conventional acid-base method also has the following defects. First, the concentrated sulfuric acid used as a catalyst requires a large amount, which is easy to corrode the equipment. Moreover, there are many side reactions, which will react with the metal ions contained in the oil to produce acid residue and sulfate residue, which will not be easily removed in the process water, and will also make the prepared ester contain salt, with high conductivity and COD High, increasing the difficulty of processing; second, some free fatty acids will be produced in the reaction stage, but the homogeneous catalyst is more sensitive to free fatty acids, and it is easy to undergo saponification reaction with fatty acids, making the esters difficult to separate; third, because it is homogeneous and reverse , the remaining catalyst is difficult to remove, and the subsequent separation is also difficult, resulting in difficulty in catalyst recovery

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