CN1321103C

CN1321103C - Process for removing unreacted alcohols from ester product mixtures using a rotating packed bed

Info

Publication number: CN1321103C
Application number: CNB03148848XA
Authority: CN
Inventors: 刘文宗; 林佳璋; 杨胜; 何宗仁; 余铧堂
Original assignee: Industrial Technology Research Institute ITRI
Current assignee: Industrial Technology Research Institute ITRI
Priority date: 2003-06-13
Filing date: 2003-06-13
Publication date: 2007-06-13
Anticipated expiration: 2023-06-13
Also published as: CN1566067A

Abstract

The present invention relates to a process for removing unreacted alcohols from an ester product mixture using mass transfer equipment, particularly rotating packed beds. The invention feeds the ester product mixture to the vicinity of the axial center of the rotating packed bed, and makes the ester product mixture radially flow through the rotating packed bed; simultaneously introducing a gas into the rotating packed bed such that the ester product mixture contacts the gas as it flows radially through the packing, whereupon unreacted alcohols and other low molecular weight volatile components contained in the ester product mixture are stripped by the gas and discharged from the top of the rotating packed bed, and collecting a purified ester product at the bottom of the rotating packed bed.

Description

Utilize rotating packed bed by the method for removing unreacted alcohols in the ester class product mixtures

Technical field

The invention relates to a kind of matter of utilizing and pass equipment, especially rotating packed bed, from ester class product mixtures, remove the method for unreacted alcohols.

Background technology

Ester class product is to be generated by organic acid and alcohol reaction, often alcohol is added in its procedure for producing that excessive traditional response procedures is that the reactive tank top connects distillation tower, and evaporant water is separated with alcohol to impel reaction comparatively fast to finish, and water takes out alcohol reflux and continues reaction so that finish.Again alcohol is distillated after reaction is finished, will adopt this moment vacuum distilling remaining alcohols could be removed.It is under low-pressure state that general alcohols is removed, and needs consuming time very of a specified duration.But heating can make ester class product quality variable color deterioration for a long time.The known most employing of method that removes alcohols at present under low pressure uses rare gas element to blow down to 5000ppm, is applicable to that as reducing to the toiletries product needs 50～500ppm, and required consumed time more reached more than 12 hours.

Remove the mode (as the aeration-agitation groove) that alcohols adopts the aeration gas bubble more at present, but because the formed effective gas-to-liquid contact area of bubble is less and gas-to-liquid contact face renewal rate is slow in the liquid phase, it is limited that the matter that rare gas element dissolves in liquid phase passes effect, so that processing efficiency is bad.Therefore need to promote amount of inert gas, reduce pressure or improve temperature, to reach required efficient.

In recent years, the research of rotating packed bed and application solved many under normal gravity field insoluble problem.Especially rotating packed bed can greatly be strengthened matter and passes process, makes tens meters high towers can be with the rotating packed bed about 2 meters.In separation processes such as absorption, stripping, distillation, use and all obtained beyond thought effect.For example United States Patent (USP) the 4283255th; 4382045; 4382900; And No. 4400275.Chinese patent publication number CN116146A (1996) proposes to use this matter to pass the preparation method of the ultra-fine grain of equipment, wherein multiple phase material flow is fed to the shaft core position of a rotating packed bed through sparger by the inner and outer pipe of concentric tubes, by the rotational gravity field action, in packed bed the contact and react.Because this technology is the new technology that the eighties just occurs, inner matter passes mechanism also continuing exploration, so its new Application Areas also needs to continually develop, does not see open report as yet as the application in dealcoholysis.

Summary of the invention

Main purpose of the present invention provides a kind of method of removing unreacted alcohols from ester class product mixtures, and it has can reduce the rare gas element usage quantity, do not need to improve ester class product mixtures temperature, and can reduce advantage such as treatment time.

The present invention utilizes rotating packed bed to change the gas-to-liquid contact mode, by effect than high centrifugal force and weighting material, ester class product mixtures is cut into than thin liquid film with than small droplets, to cause high gas-to-liquid contact area and high-quality transfer efficiency, so will make alcohols easier by removing in the ester class product mixtures, reduce so that the time that removes shortens, ester class product quality improves, contain the alcohol amount, and then promote industrial utilization.

Embodiment

A kind ofly remove the method for unreacted alcohols with rotating packed bed from ester class product mixtures, wherein this ester class product has 10 to 30 carbonatoms, and this method comprises the following step:

A) an ester class product mixtures is fed to a ring rotation packed bed in axle center rotation, this rotating packed bed is to be positioned at a cabin (housing), makes this ester class product mixtures radial flow cross weighting material in this rotating packed bed;

B) simultaneously a gas is imported this rotating packed bed, make this ester class product mixtures when radial flow is crossed this weighting material, contact with this gas, so the contained unreacted alcohols of this ester class product mixtures is this gas institute's stripping and is discharged by the top in this cabin, and collects the ester class product of a purifying in the bottom in this cabin.

Preferable, the ester class product mixtures of step a) is that the axle center district by this rotating packed bed is imported into.

Preferable, the gas of step b) is that the periphery by this cabin is imported into, so this ester class product mixtures contacts with this back flow of gas when radial flow is crossed this weighting material.

Preferable, the gas of step b) is that the axle center district by this rotating packed bed is imported into, so this ester class product mixtures contacts with this gas following current when radial flow is crossed this weighting material.

Preferable, the gas of step b) is that the bottom by this rotating packed bed is imported into and is flowed out by the top of this rotating packed bed, so this ester class product mixtures contacts with this gas cross-flow when radial flow is crossed this weighting material.

Preferable, one negative pressure is bestowed the axle center district of this rotating packed bed, make this ester class product mixtures when radial flow is crossed this weighting material, under the low pressure situation, contact, and the axle center district of the gas that contains steam stripped unreacted alcohols by this rotating packed bed discharged by the top in this cabin with this gas.

Preferable, the inventive method further comprise the purifying that step b) is collected ester class product whole or a part of as the charging repeating step a) and b), have the purity of wanting up to the ester class product of the purifying that is obtained.

Preferable, the gas of step b) is nitrogen, carbonic acid gas, argon gas or water vapor.

Below, will graphicly the present invention be described with reference to unique with a preferred embodiment.One is suitable for rotating packed bed of the present invention system is shown in Fig. 1.As shown in Figure 1, the ester class product mixtures in the material trough (1) is squeezed into the axle center district of a ring rotation packed bed via lift pump 2 by liquid-inlet 3, by liquid distributor 4, sprays to annular packing 5 equably.Driving by variable speed motor 6 produces great centrifugal force, with liquid quick travel outward, comes together in the bottom in the cabin 7 of rotating packed bed, is discharged by liquid exit 8 at last.Utilizing rare gas element 9 not participate in the gas that reacts as nitrogen, carbonic acid gas, argon gas or other is simultaneously entered by the gas feed 10 of rotating packed bed, in filler 5 with ester class product mixtures counter current contact, so will take away unreacted alcohols contained in the ester class product mixtures, the rare gas element that contains alcohols is at last discharged by pneumatic outlet 11.

Description of drawings

Fig. 1 is the schematic flow sheet of preferred embodiment of the present invention.

Reference numeral

1 material trough, 2 lift pumps

3 liquid-inlets, 4 liquid distributors

5 annular packings, 6 variable speed motors

7 cabins, 8 liquid exits

10 gas feeds of 9 rare gas elementes

11 pneumatic outlets

Embodiment

Embodiment 1

The system that use is similar to Fig. 1 carries out butyl stearate (BST) batch and removes propyl carbinol (NBA) test.The rotating packed bed specification is: internal diameter 78mm, external diameter 160mm, thickness 20mm.Rotating speed is fixed in 1300rpm.Employed weighting material is stainless steel metal silk screen (the specific surface area 1906m of braiding ²/ m ³).The filling voidage of rotating packed bed is that 0.91 (voidage is not 1 when filling weighting material; Filling voidage during completely filled is 0), be air release agent with nitrogen.During experiment BST being fed to rotating packed bed by liquid-inlet 3 also will be imported in the material trough 1, to be back to material trough 1 again by the liquid product that liquid exit 8 comes out.Experiment condition and resulting result are as table.Table can be found thus, reduces to 237ppm in the 7th minute its NBA of purified product from liquid exit 8 samplings, and in the 12nd minute sampling person, its NBA reduced to 43ppm.

Embodiment 2

The system that use is similar to Fig. 1 carries out butyl stearate (BST) continous way and removes propyl carbinol (NBA) test.The rotating packed bed specification is: internal diameter 20mm, external diameter 40mm, thickness 20mm.Rotating speed is fixed in 1300rpm.Employed weighting material has specific surface area 1546m for braiding stainless steel metal wire netting gear ²/ m ³The filling voidage of rotating packed bed is 0.90.With the water vapor is air release agent, and bleeds and operate in low pressure by gas feed 10.During experiment BST is fed to rotating packed bed and is collected purified product by liquid exit 8 by liquid-inlet 3.Experiment condition and resulting result are as table.Table can be found thus, handles to make NBA reduce to 43～49ppm continuously in low pressure through rotating packed bed.

Embodiment 3

Except replacing BST as the charging, repeat to execute the step of example 2 and carry out the test that continous way removes sec-n-octyl alcohol (2-EH) with iso-octyl palmitate (EHP).Experiment condition and resulting result are as table.Table can be found thus, handles continuously in low pressure that through rotating packed bed 2-EH is reduced to below the 100ppm.

Claims

1. A method for removing unreacted alcohols from ester product mixtures with a rotating packed bed, wherein the ester product has a carbon number of 10 to 30, the method comprising the following steps:

a) Feed an ester product mixture to an annular rotating packed bed rotating around an axis, the rotating packed bed is located in a chamber, and the ester product mixture flows radially through the rotating packed bed filler;

b) Simultaneously introducing a nitrogen, carbon dioxide, argon or water vapor gas into the rotating packed bed so that the ester product mixture contacts the gas as it flows radially through the packing, so that the ester product mixture contains Unreacted alcohol is stripped by the gas and exits the top of the chamber, and a purified ester product is collected at the bottom of the chamber.

2. The method as claimed in claim 1, wherein the ester product mixture of step a) is introduced from the axial center region of the rotating packed bed.

3. The method of claim 2, wherein the gas of step b) is introduced from the periphery of the chamber so that the ester product mixture is in countercurrent contact with the gas as it flows radially through the packing.

4. The method of claim 2, wherein the gas of step b) is introduced by the axial center region of the rotating packed bed, so that the ester product mixture is co-current with the gas when flowing radially through the packing touch.

5. The method of claim 2, wherein the gas of step b) is introduced from the bottom of the rotating packed bed and flows out from the top of the rotating packed bed, so that the ester product mixture flows radially through the packed cross-flow contact with the gas.

6. The method of claim 3, wherein a negative pressure is applied to the axial region of the rotating packed bed so that the ester product mixture contacts the gas at low pressure while flowing radially through the packing , and the gas containing stripped unreacted alcohols is discharged from the top of the chamber through the axial region of the rotating packed bed.

7. The method of claim 1, further comprising using all or a part of the purified ester product collected in step b) as a feed and repeating steps a) and b) until the obtained purified ester The product has a desired purity.

8. The method of claim 1, wherein the ester product is butyl stearate, and the unreacted alcohol is n-butanol.

9. The method of claim 1, wherein the ester product is isooctyl palmitate, and the unreacted alcohol is 2-octanol.