JP5376110B2 - High-purity carboxylic alcohol ester purification method and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a carboxylic acid ester in a high reaction efficiency in simple separation by transesterification reaction of a carboxylic acid glyceride and an alcohol. <P>SOLUTION: An alcohol necessary for a reaction and an alkali catalyst are supported on glycerol impregnated into a porous body and a crude carboxylic acid alcohol ester after a primary reaction is passed through the porous body. Glycerol is supported on a porous body and the carboxylic acid alcohol ester after the primary reaction is passed through the porous body. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

The present invention relates to a high-purity carboxylic alcohol ester purification method and an apparatus thereof in an ester substitution reaction of a carboxylic acid glyceride and an alcohol.

In the ester substitution reaction equipment of carboxylic acid glyceride and alcohol using an alkali catalyst, glycerin generated during the reaction promotes adsorption and uneven distribution of the alkali catalyst, rapidly impairing the persistence of the ester substitution reaction, and the reaction convergence is 95 ~ Stops at 98%.

Some of the measures taken to accelerate the reaction include equipment that raises the reaction tank to high temperature and pressure, but because the reaction tank is pressure-resistant, airtightness and pressure resistance (high strength) are required. Becomes expensive.

Some of the other methods include a step of mixing a large amount of alcohol and a small amount of an alkali catalyst in order to promote the secondary reaction. After that, when equipment such as fractional distillation for alcohol recovery becomes large At the same time, a large amount of energy is consumed.

Since high reaction convergence is difficult in this way, the reaction intermediate monoglyceride or the like inhibits low-temperature performance (filter clogging point and the like).

Part of the method of removing the alkali catalyst is stationary storage, but the removal efficiency is poor and the alkali catalyst of around several hundred PPM remains.

Although there is a technique using activated clay for adsorption of other alkali catalysts, the activated clay also takes in a highly viscous liquid such as glycerin and easily accumulates in the unit, requiring frequent maintenance.

Many techniques for removing the catalyst of the crude carboxylic acid alcohol ester after completion of the reaction tank are required for washing with water, but the remaining amount of the alkali catalyst is large, resulting in problems such as a decrease in yield.

At this time, water, soap, and carboxylic alcohol ester are emulsified, making separation difficult, and with the addition of various chemicals, along with cost increase, fatty acids and alcohol in the soap are further generated by washing the catalyst with water, It becomes a factor that pollutes water quality.
Patent Documents 1 and 2 are known as methods for producing fatty acid methyl esters.
JP2007-211139 JP2008-024841

In the ester substitution reaction equipment of carboxylic acid glyceride and alcohol using alkali catalyst, glycerin generated in the reaction process adsorbs and disperses the alkali catalyst, rapidly inhibits the persistence of the reaction, and the reaction convergence is 95-98% Will stop at.

In addition, due to the increase in the size of the reaction tank, it is more difficult to uniformly disperse oil and fat molecules, alkali catalyst, and alcohol molecules with only a stirring blade.

In the carboxylic alcohol ester immediately after the reaction, several hundred to several thousand PPM of an alkali catalyst remains.

Therefore, at the time of washing with water, these esters and alkali catalyst react with water, and some of them change into alcohol and soap to reduce the yield, and the carboxylic acid alcohol ester, soap and water become milky, making separation difficult and washing. Significantly worsens the wastewater COD.

Method 1: Impregnating a porous body such as a cellulose filter with glycerin containing methanol and an alkali catalyst in an arbitrary ratio, and the crude carboxylic alcohol ester having undergone the ester substitution primary reaction has the thermal energy necessary for the reaction. To the porous body.

Method 2: impregnating a porous body such as a filter with glycerin, and bringing the crude carboxylic alcohol ester, which has completed the method 1, to a room temperature or less, and guiding it to the porous body.

Effect of Method 1; When the unreacted tricarboxylic acid glyceride or the remaining crude carboxylic acid alcohol ester of the intermediate mono-dicarboxylic acid glyceride passes through the porous material, glycerin is adsorbed together with glycerin in the micron-order voids. -There is methanol and alkali catalyst to be retained, which promotes further ester substitution reaction. (Secondary reaction)

New glycerin generated during the reaction is adsorbed to the previously impregnated glycerin due to its high viscosity.

The glycerin impregnated in the porous body adsorbs the glycene newly generated by the ester substitution reaction, while saturating several vol% methanol remaining in the crude carboxylic alcohol ester and several hundred to several thousand PPM alkaline catalyst to saturation. Adsorption makes it possible to maintain the environment necessary for the ester substitution reaction.

When the glycerin molecules adsorbed in the micron-order voids become excessive, they are separated as oil droplets from the porous body and settled.

As a result of Method 1, a highly efficient carboxylic alcohol ester reaction can be obtained, and at the same time, the amount of alkali catalyst can be reduced to several tens of PPM.

Effect of Method 2; The glycerin slightly remaining in the liquid in Method 1 is further adsorbed by the glycerin impregnated in the porous body as the viscosity further increases at low temperature, and further alkali catalyst from the carboxylic alcohol ester Is removed by adsorption.

Thereby, the amount of glycerol remaining in the carboxylic acid alcohol ester and the amount of alkali catalyst are reduced to 0 to several PPM.

When glycerin adsorbs the alkali catalyst to a saturated state, the liquid containing the alkali catalyst component leaks, but the subsequent hydrogen-substituted ion exchange resin adsorbs the alkali catalyst and discharges water.

The generation of water is confirmed by visual observation or the like, and is switched to the spare filter MF2, so that the alkali catalyst can be removed continuously.

Method 1 will be explained with reference to FIG. 1. From the reaction tank after the reaction or the storage container T1 of the crude carboxylic alcohol ester after the reaction, the crude carboxylic alcohol ester is passed through the prefilter PF and the main filter MF1 through the pump. And store in container T2.

Prior to passing the crude carboxylic acid alcohol ester, an alkali catalyst such as KOH is dissolved in alcohol, and a liquid in which glycerin is mixed is impregnated in the filter MF1.

In a small cell inside the filter, alcohol and an alkali catalyst are present together with glycerin.

Here, unreacted fats and oils (tricarboxylic acid glycerides) and mono-dicarboxylic acid glycerides contained in the crude carboxylic acid alcohol ester are induced and reacted.

The temperature required for the ester substitution reaction is given to the crude carboxylic alcohol ester stored in the container T1 by the heating device HT while monitoring the thermometer TI.

The heat energy required for the reaction can be obtained by keeping the liquid immediately after the reaction in the reaction tank warm.

Until the liquid temperature of the unit in FIG. 1 reaches the required temperature, the liquid that has passed through the filter MF1 is returned to the container T1.

If the crude carboxylic alcohol ester has the necessary heat energy as the residual heat after the ester substitution reaction in the reaction vessel, there is no need for heating.

While monitoring the flow meter FI with the pump P, the crude carboxylic alcohol ester having a constant flow rate is sent to the filter MF1.

The filter area (number of cells) and the flow rate adjustment are in a proportional relationship, and the flow rate adjustment and temperature show a relationship similar to an inverse proportion from the relationship of viscosity.

The crude carboxylic alcohol ester fed by the pump P removes the clogs with the pre-filter PF and prevents the filter MF1 from being clogged.

The clogging of the prefilter PF is monitored with the pressure gauge PI.

When the required temperature is reached in the thermometer TI, the liquid that has passed through the filter MF1 is sent to the container T2.

In FIG. 2, Method 2 will be explained. An apparatus for removing glycerin and an alkali catalyst from the crude carboxylic alcohol ester after Method 1 is completed.

The filter MF2 is impregnated with glycerin in advance.

First, in FIG. 2, the slightly settled glycerin is removed from the container T2.

The crude carboxylic alcohol ester after finishing the method 1 is cooled with a heat exchanger (or a cooler) HT so that the temperature becomes equal to or lower than normal temperature with a thermometer TI.

The flow rate is adjusted while monitoring the flow meter FI with the pump P, and the liquid in the container T2 is sent to the filter MF2.

The liquid that has passed through the filter MF2 is returned to the container T2 until the liquid temperature is stabilized at room temperature or lower.

When the temperature stabilizes below room temperature, the solution is sent to the container T3.

When the ability of the filter MF2 to remove the alkali catalyst is lost, water accumulates at the bottom of the resin tower IMF containing the hydrogen ion exchange resin.

As soon as water is observed, switch the circuit to the spare filter MF2.

The liquid is returned to the container T2 until the temperature is stabilized at room temperature or lower, and when the temperature is stabilized at room temperature or lower, the liquid is fed again to the container T3.

In order to maintain the reaction at a high rate, the liquid temperature and the liquid feeding speed tend to be inversely proportional, and the filter area and the liquid feeding speed tend to be proportional.

Measure the pressure, temperature, and flow rate for monitoring, and switch the bypass valve when clogging or functional degradation is observed.

In the production of fatty acid methyl ester (FAME) that moves from primary reaction to (warm) water washing, the unit of FIG. 1 or FIG. 2 can be retrofitted.

A plurality of units of the heat exchanger HT and the filter MF1 in FIG. 1 are connected, and the appropriate temperature for the reaction with respect to triglyceride and mono-diglyceride is given to each by the heat exchanger HT, and the liquid is passed.

In FIG. 2, a plurality of glycerin-impregnated filters MF2 may be connected.

Fatty acid methyl ester (FAME) fuel production

Conceptual diagram of a device that promotes high reaction rate of carboxylic alcohol ester Conceptual diagram of equipment for removing glycerol / alkali catalyst from carboxylic alcohol ester

Explanation of symbols

T1: Reaction tank or storage tank for crude alcohol carboxylic acid ester immediately after reaction
HT: Heating / cooling device such as heat exchanger or heater
P: Pump
PI: Pressure gauge
PF; Pre-filter
MF1: Main filter (glycerin / alkaline catalyst / alcohol impregnation or alkali catalyst / alcohol impregnation)
MF2: Main filter (glycerin / alcohol impregnation or glycerin impregnation)
IMF: ion exchange resin tower (hydrogen-substituted resin)
TI: Thermometer
FI; flow meter
T2; storage container
T3; Storage container

Claims (4)

The crude carboxylic alcohol ester, which has been subjected to the primary reaction of ester substitution, is impregnated in the porous body by holding the alcohol / alkaline catalyst necessary for the reaction in glycerin, and the thermal energy necessary for the reaction is given to the porous body. A production method that converges an ester substitution reaction at a high rate, characterized by being liquidated. The crude carboxylic alcohol ester, which has been subjected to the primary reaction of ester substitution, is impregnated in the porous body by holding the alcohol / alkaline catalyst necessary for the reaction in glycerin, and the thermal energy necessary for the reaction is given to the porous body. A device that converges the ester substitution reaction at a high rate, characterized by being liquid. Adsorption of alkali catalyst characterized in that the crude carboxylic alcohol ester treated in claim 1 by impregnating glycerin into the porous body or the crude carboxylic alcohol ester after the ester substitution primary reaction is passed through the porous body. -Removal method. Adsorption of alkali catalyst characterized in that the crude carboxylic alcohol ester treated in claim 1 by impregnating glycerin into the porous body or the crude carboxylic alcohol ester after the ester substitution primary reaction is passed through the porous body. -Removal device.

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