WO2007098638A1

WO2007098638A1 - A power external circulation estering reactor

Info

Publication number: WO2007098638A1
Application number: PCT/CN2006/000291
Authority: WO
Inventors: Wende Luo; Huatang Zhou; Qigui Zhou; Chun Zhang; Wangsheng Wan; Haodong Xu
Original assignee: China Textile Industrial Engineering Institute
Priority date: 2006-02-28
Filing date: 2006-02-28
Publication date: 2007-09-07
Also published as: WO2007098638A8

Abstract

A power external circulation estering reactor comprises a heating reaction device, a evaporating reaction device, a power external impelling device, wherein the heating reaction device includes a vertical type coiler heating reactor whose exit and inlet connect with the evaporating reaction device and power external impelling device respectively, the evaporating reaction device includes a reaction container with a gas exit at the top. The upper part and lower part of the reaction container are upper evaporation zone and lower reaction zone respectively. The bottom of the reaction container connects with the power external impelling device that is mechanical and locates at the exterior of the evaporating reaction device.

Description

External power circulating esterification reactor

The invention relates to a novel external power circulating esterification reactor, in particular to a new type of ethylene glycol (EG) and terephthalic acid (PTA) esterification to form ethylene terephthalate (BHET). Power cycle esterification reactor. Background technique

In the chemical fiber industry, the process of polyethylene terephthalate (PET) is to first mix the raw materials of ethylene glycol (EG) and terephthalic acid (PTA) into a slurry, and then at a certain temperature and pressure. The slurry is subjected to an esterification reaction to form ethylene terephthalate (BHET), and the resulting ethylene terephthalate is further subjected to polycondensation treatment to form polyethylene terephthalate. In this production process, the process of the esterification reaction process is completed in a full-mix reactor with a stirrer, but the structure of the esterification reactor with a stirrer is complicated; especially after the device is enlarged. Manufacturing and transportation are very difficult and other issues.

In response to this problem, the process of esterification treatment is currently completed in a fully mixed reactor that relies on thermodynamic cycles, which requires a large amount of ethylene glycol to participate in the cycle, allowing more ethylene glycol to vaporize. A sufficient density difference is obtained; it can be seen from the experiment that in the ordinary thermodynamic cycle, the esterification reaction can be carried out only when the molar ratio (EG/PTA) is greater than 2.0 and the reaction temperature is > 290" €, such a large amount of ethylene glycol It circulates, vaporizes, and cools in the system, causing the energy to be consumed in vain. At the same time, the volume of the reactor system is too large, there are transportation difficulties, and the use of a larger-scale equipment for trial production is limited.

To this end, the inventors of the present invention have invented a new type of external power circulating esterification reactor combining thermodynamic cycle and external power cycle, which can reduce the circulation amount of ethylene glycol material, and save energy and reduce the device. Under the condition of equipment volume and cost reduction, the purpose of large-scale esterification equipment is achieved and transportation is convenient. Summary of the invention

The object of the present invention is to propose a cyclic esterification reactor with external power, which improves the complex structure and reverse of the prior art esterification reactor. The problem that the height of the reactor is too high, the molar ratio of ethylene glycol in the raw material is too large, the energy consumption is high, and the start-stop reaction procedure is complicated, thereby achieving the purpose of large-scale esterification device and convenient transportation under the condition of reducing equipment volume and reducing cost. .

The object of the present invention is achieved by the novel external power circulating esterification reactor of the present invention. The externally driven circulating esterification reactor of the present invention comprises a heating reaction device, an evaporation reaction device, and an external power driving device, characterized in that:

The heating reaction apparatus comprises a vertical coil heating reactor, and an outlet of the vertical coil heating reactor is connected to the evaporation reaction device, and the lower portion of the vertical coil heating reactor inlet is connected to the external power driving device;

The evaporation reaction device comprises a reaction vessel, the upper part of the reaction vessel is an upper evaporation zone, the lower part of the reaction vessel is a lower reaction zone, and has a vapor phase outlet at a top portion thereof, a material outlet at a lower side thereof, and a bottom portion connected to the external power driving device;

The external power driving device is a mechanical external power driving device which is disposed outside the evaporation reaction device and is respectively connected to the heating reaction device and the evaporation reaction device, so that the external power circulating esterification reactor constitutes a whole of the closed cycle.

In a preferred embodiment of the present invention, the heating reaction apparatus includes an inlet of a reaction material, a vertical coil heating reactor, a draft tube, a reactant outlet tube, and a flat plate distributor for uniformly distributing the material. Wherein the heating reaction device is connected to the upper evaporation zone of the evaporation reaction device through a draft tube and a reactant outlet pipe.

In another preferred embodiment of the invention, the plate dispenser is located at the bottom inlet of the heated reaction unit.

In another preferred embodiment of the invention, the evaporation reaction apparatus includes an upper evaporation zone, a lower reaction zone, a vapor phase outlet pipe, and a reaction product outlet in the reaction vessel.

In another preferred embodiment of the present invention, the external power driving device is a lateral high-efficiency axial flow conveying device located in a stirrup tube respectively connected to the heating reaction device and the evaporation reaction device, which comprises a sickle tube and is highly efficient Rowing impeller, seal, agitator drive, agitator shaft and baffle.

In another preferred embodiment of the present invention, the esterification reactor further comprises a heat retention heating device comprising a reactant outlet pipe heat medium jacket, an evaporation reaction device evaporation zone heat medium jacket and a crucible tube heat Media jacket. In another preferred embodiment of the invention, the heat retention heating device employs a vapor phase heat medium.

The externally driven circulating esterification reactor of the present invention utilizes a combination of thermodynamic cycle and external power cycle, and reduces reactor volume and reaction on the basis of fully utilizing the ratio of thermodynamic cycle and external power cycle adaptation. The structure of the device is compact, and the vapor phase outlet is arranged at the top of the reactor, which relatively increases the vapor phase space of the reactor and reduces the vapor phase entrainment. The material outlet is placed on the lower side of the reactor, and the material utilization level is high and the gravity flows into the next reactor, eliminating the transfer pump and saving the device to deliver energy. In contrast to the top-mounted agitator, the external power drive unit with a lateral axial flow conveyor allows the esterification unit to operate while saving energy, reducing equipment space, increasing equipment safety, and reducing equipment investment. The heating device and the heat preservation heating device all use the gas phase heat medium, which can reduce the amount of heat medium loading, not only saves one-time investment, but also reduces environmental pollution. DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic view showing the structure of a preferred embodiment of the cyclic esterification reactor having an external power. detailed description

The invention is described in detail below with reference to the accompanying drawings, but does not constitute a limitation of the invention:

First, the externally-circulating cyclic esterification reactor of the present invention comprises a heating reaction device 10, an evaporation reaction device 20, an external power driving device 30, and heat insulating devices 14, 23, 26. Wherein, the heating reaction device 10 includes an inlet 16 for the reaction material, a vertical coil heating reactor 11, a plate distributor 15, a flow guiding tube 12, and a reactant outlet pipe 13, wherein the heating reaction device 10 passes through the gas guiding tube 12 and reacts The outlet pipe 13 is connected to the upper evaporation zone 21 of the evaporation reaction device; the evaporation reaction device 20 includes an upper evaporation zone 21, a lower reaction zone 24, a vapor phase outlet pipe 22, and a ruthenium product in the reaction vessel 28. Outlet 25; the external power drive unit 30 is a lateral high efficiency axial flow conveyor located in a U-shaped tube 27 connected to the heating reaction unit 10 and the evaporation reaction unit 20, respectively, comprising a weir tube 27, a stirring drive 35 High-efficiency forced discharge impeller 34, seal 31, agitator shaft 32 and baffle 33. The heat preservation heating device comprises a reactant outlet pipe heat medium jacket 14, an evaporation reaction device evaporation zone heat medium jacket 23 and a crucible pipe heat medium jacket 26.

Specifically, the raw material enters the esterification reaction device from the material inlet 16 at the junction of the bottom of the coil heat exchange reactor and the U-shaped tube, and is mixed with the circulating material through the flat plate distributor 15 to enter the coil heat exchange reactor 11 . The formed slurry is rapidly heated in the coil heat exchange reactor 11 to be vaporized, and the material enters the evaporation reaction device 20 via the flow guiding cylinder 12 and the reactant outlet pipe 13 in the upper portion of the coil heat exchanger 11 In the vessel 28, the reaction is carried out in the upper evaporation zone 21. The resulting vapor phase is withdrawn from the top vapor phase outlet tube 22 of the reactor, and the liquid phase enters the lower reaction zone 24 of the reactor evaporation reaction unit to continue the reaction. A portion of the material produced is passed through the material outlet 25 to the esterification reactor. Most of the material passes through the weir tube 27 which is connected to the heating reaction unit 10 and the evaporation reaction unit 20, respectively, and passes through the external power driving unit 30 to enter the next cycle.

Taking ethylene glycol and terephthalic acid as raw materials to produce ethylene terephthalate as an example, it can be seen that the reactants need sufficient circulation force to achieve full mixing. The circulating power in the esterification apparatus of the present invention consists of the following two parts: Part of the material is a density difference formed by the material forming a low-density vapor-liquid mixture after absorption and a higher density liquid material in the reactor, and the difference in density of the portion The thermosiphon power converted into is called thermal cycle power; the second part is the mechanical cycle power provided by the external power drive. If a device that utilizes thermal cycling power is fully utilized, a large amount of ethylene glycol is required to participate in the cycle, allowing more ethylene glycol to vaporize, thereby obtaining a sufficient amount of density difference. The prior art test data shows that in the ordinary thermodynamic cycle, the esterification reaction is only in the molar ratio.

(EG/PTA) When the reaction is more than 2.0, the reaction can proceed smoothly. A large amount of ethylene glycol circulates, vaporizes, and cools in the system, and the energy is consumed in vain. At the same time, the volume of the reactor system appears to be too large, making the esterification reactor difficult to transport, and the scale of equipment manufacturing is also limited. The esterification reactors produced in accordance with the present invention can be separated by components during transport, and the transport volume and weight are greatly reduced. The esterification reaction can be carried out smoothly at a low ethylene glycol/terephthalic acid molar ratio, wherein the ethylene glycol/terephthalic acid molar ratio is preferably from 1.0 to 1.90:1, more preferably from 1.0 to 1.70: 1, all equipment capacity can be reduced. Conducive to energy saving and large-scale installation. The energy consumption of the esterification reactor manufactured according to the present invention is about one third of the original reactor energy consumption, and the daily production can reach 600 tons to 1500 ρ屯 or more. The esterification reactor of the present invention utilizes a combination of a thermodynamic cycle and an external power cycle, and further, the inventors of the present invention have conducted extensive research on the ratio of the thermal cycle power and the mechanical cycle power in the material circulation power of the reactor. Taking ethylene glycol and terephthalic acid as raw materials to produce ethylene terephthalate as an example, it is found that when the ratio of thermal cycle power and mechanical cycle power is 0.1 to 0.6:1, the economic benefit of the device will reach the best.

In particular, the flat plate dispenser 15 allows the materials to be hooked and then enters the heating reaction device 10, facilitating the efficient reaction.

Further, the esterification apparatus of the present invention is provided with a heat medium jacket having a heat retaining function at the reactant outlet pipe, the evaporation zone of the evaporation reaction device, and the U-shaped pipe, and the vapor phase heat medium is used to greatly improve the heat supply efficiency. Since the esterification reaction requires a large amount of heat, the use of the vapor phase heat medium of the esterification apparatus of the present invention increases the production efficiency of the esterification reaction. Example

The specific embodiment of the present invention will now be described in further detail by taking esterification reaction of ethylene glycol (EG) and terephthalic acid (PTA) as raw materials to form ethylene terephthalate (BHET).

Ethylene glycol (EG) and terephthalic acid (PTA) are formulated into a fresh slurry at a molar ratio of 1.0-1.70:1, and are fed from the material inlet 16 at the junction of the bottom of the coiled heat exchanger and the crucible tube. Adding to the esterification reaction device, mixing with the circulating material, entering the coil heat exchange reactor 11, the slurry is rapidly heated in the coil heat exchange reactor 11, the temperature is raised, and a reaction occurs, while the esterification reaction is being carried out. Part of the ethylene glycol and water are vaporized, so a lower density vapor-liquid mixed phase is formed in the upper portion of the tube of the coil heat exchange reactor 11, in the difference in density (ie, thermal cycle power) and located in the heating reaction device 10 and evaporation, respectively. Under the push of the external power drive unit 30 (i.e., external circulation power) in the stirrup tube 27 connected to the reaction device 20, the material enters the evaporation via the guide tube 12 and the reactant outlet tube 13 in the upper portion of the coil heat exchange reactor 11. The vapor-liquid separation occurs in the reaction vessel 28 of the reaction device 20, and the slurry and the unvaporized ethylene glycol are esterified to form an esterified product and water, wherein the reaction pressure is 0.15-0.25 MPa and the reaction temperature is 260-300 °. C. The water and excess ethylene glycol are partially vaporized at a high temperature, and the vapor phase of ethylene glycol and water is discharged from the vapor phase outlet pipe 22 at the top of the reactor, and the liquid phase enters the reaction zone 24 of the lower portion of the reactor in the reaction zone during the residence time. , continue to react Separated from vapor and liquid. A portion of the material exits the esterification reactor through material outlet 25. Most of the material is then mixed with the fresh feed and then passed to the next cycle via the external power drive unit 30 in the manifold 27 connected to the heated reaction unit 10 and the evaporation reaction unit 20, respectively. Among them, the research of the invention finds that the ratio of the thermal cycle power and the mechanical cycle power is preferably 0.1 to 0.6:1, and the economic benefit of the device will be the best. The product obtained was ethylene terephthalate with an esterification rate of 90-96%.

Claims

Rights request

A cyclic esterification reactor having an external power, comprising a heating reaction device (10), an evaporation reaction device (20), and an external power driving device (30), wherein the characteristic is

The heating reaction device (10) comprises a vertical coil heating reactor (11), and an outlet of the vertical coil heating reactor (11) is connected to the evaporation reaction device (20), the vertical coil heating reactor The lower portion of the inlet is connected to the external power driving device (30); the evaporation reaction device (20) includes a reaction vessel (28), the upper portion of the reaction vessel (28) is the upper evaporation zone (21), and the lower portion of the reaction vessel is the lower reaction The zone (24) has a vapor phase outlet ( ² 2) at the top thereof, a material outlet ( ²⁵ ) on the lower side thereof, and a bottom portion connected to the external power driving device (30);

The external power drive device ( ³⁰ ) is a mechanical external power drive device disposed outside the evaporation reaction device (20) and connected to the heating reaction device (10) and the evaporation reaction device (20), respectively. The power cycle esterification reactor constitutes the entirety of the closed cycle.

2. The externally powered cyclic esterification reactor according to claim 1, characterized in that the heating reaction device (10) comprises an inlet (16) of a reaction material, a vertical coil heating reactor (11), a guide a flow tube (12), a reactant outlet tube (13), and a flat plate distributor (15) for uniformly distributing the material, wherein the heating reaction device (10) is passed through the flow guiding tube (12) and the reactant outlet tube (13) The upper evaporation zone (21) of the evaporation reaction device is connected.

3. An externally powered circulating esterification reactor according to claim 2, characterized in that the plate distributor (is) is located at the bottom inlet of the heating reaction unit (10).

4. The externally-circulating cyclic esterification reactor according to any of the preceding claims, wherein the evaporation reaction device (20) comprises an upper evaporation zone (21) in the reaction vessel (28), a lower portion Reaction zone (24), vapor phase outlet pipe (22) and reaction product outlet (25).

5. Circulating esterification reactor with external power according to any of the preceding claims, characterized in that the external power drive (30) is located separately from the heating reaction device (10) and the evaporation reaction device (20) Lateral inside the connected sickle tube (27) High-efficiency axial flow conveyor consisting of a stirrup tube (27), agitator drive (35), high-efficiency forced-discharge impeller (34), seal (31), agitator shaft (32) and baffle (33)

6. An externally powered cyclic esterification reactor according to any of the preceding claims, further comprising a heat retention heating device (14, 23, 26) comprising a reactant outlet tube heat The medium jacket (14), the heat medium jacket (23) in the evaporation zone of the evaporation reaction device and the heat medium jacket (26) of the crucible tube.

The cyclic esterification reactor having an external power according to any of the preceding claims, wherein the heat retention heating device employs a gas phase heat medium.

8. An externally powered circulating esterification reactor according to any of the preceding claims for use in the preparation of ethylene terephthalate from the esterification of ethylene glycol and terephthalic acid.