阅读说明：本技术 一种糠醛气相脱羰制取呋喃的装置及方法 (Device and method for preparing furan by furfural gas-phase decarbonylation ) 是由 程光锦 王玉斌 伏忠祥 于 2020-12-25 设计创作，主要内容包括：本发明涉及一种糠醛气相脱羰制取呋喃的装置及方法,其特征在于：(1)糠醛以300-350Kg/h通入糠醛汽化塔加热器预热至110-138℃后进入汽化塔,通氢气保护,控制塔内温度130-160℃；(2)塔顶出来的气相换热后进入电加热器加热至260-330℃后进入脱羰反应器,通入氢气保护,控制反应器内温度260-350℃、压力0.01-0.03Mpa；(3)反应器出来的气相与糠醛汽化塔的气相换热后进入淬冷塔,塔底液返回糠醛汽化塔；(4)塔内气相深冷后进入粗品槽,粗品槽内气相进入吸收塔；粗品槽内液相进入精馏塔,减压精馏得合格精品呋喃。本发明优点：降低了糠醛高温副反应,呋喃转化率由原来40-45%提高至50-60%,催化剂运行周期由7-10天延长到30-60天；吨呋喃蒸汽能量消耗由原来3.5-5吨降至2-2.5吨,呋喃纯度由原来98–98.5%提高至99–99.8%。(The invention relates to a device and a method for preparing furan by furfural gas-phase decarbonylation, which are characterized in that: (1) introducing furfural into a furfural vaporization tower heater at 350Kg/h of 300-; (2) the gas phase from the tower top is subjected to heat exchange and then enters an electric heater to be heated to 260-temperature plus 330 ℃ and then enters a decarbonization reactor, hydrogen is introduced for protection, the temperature of 260-temperature plus 350 ℃ and the pressure of 0.01-0.03MPa in the reactor are controlled; (3) the gas phase from the reactor exchanges heat with the gas phase of the furfural vaporization tower and then enters a quenching tower, and the tower bottom liquid returns to the furfural vaporization tower; (4) the gas phase in the tower enters a crude product tank after being subjected to deep cooling, and the gas phase in the crude product tank enters an absorption tower; and (4) feeding the liquid phase in the crude product tank into a rectifying tower, and carrying out vacuum rectification to obtain qualified fine furan. The invention has the advantages that: the high-temperature side reaction of the furfural is reduced, the conversion rate of the furan is improved to 50-60% from the original 40-45%, and the operation period of the catalyst is prolonged to 30-60 days from 7-10 days; the energy consumption of the furan steam per ton is reduced from 3.5-5 tons to 2-2.5 tons, and the purity of the furan is improved from 98-98.5% to 99-99.8%.)

1. A device for preparing furan by gas-phase decarbonylation of furfural is characterized by comprising the following equipment:

the top of the furfural vaporization tower is connected with the bottom of a decarbonylation reactor through a pipeline and an electric heater, the top of the decarbonylation reactor is connected with a quenching tower through a pipeline, the top of the quenching tower is connected with a crude product tank through a pipeline, and the bottom of the crude product tank is connected with a rectifying tower through a pipeline; the bottom of the quenching tower is connected to a furfural vaporization tower through a pipeline, the upper part of the crude product tank is connected to an absorption tower through a pipeline, the bottom of the absorption tower is connected to the furfural vaporization tower through a pipeline, and the top of the rectification tower is connected to the upper part of the quenching tower through a pipeline and a fine product tank.

2. The device for preparing furan by gas-phase decarbonylation of furfural according to claim 1, characterized in that: the furfural vaporization tower is connected with a heater, and the heater is a thin film evaporator.

3. A method for preparing furan by gas-phase decarbonylation of furfural is characterized by comprising the following steps:

(1) introducing furfural into a furfural vaporization tower heater at the rate of 350Kg/h for 300-plus-one, preheating the furfural to the temperature of 110-plus-one and 138 ℃, introducing hydrogen into the furfural vaporization tower for protection, and controlling the temperature in the furfural vaporization tower at 160 ℃ for 130-plus-one;

(2) the gas phase from the furfural vaporization tower is subjected to heat exchange by a heat exchanger, then enters an electric heater to be heated to 260-class temperature of 330 ℃, then enters a decarbonylation reactor, is protected by introducing hydrogen into the decarbonylation reactor, controls the temperature of 260-class temperature of 350 ℃ and the pressure of 0.01-0.03MPa in the decarbonylation reactor, and generates a furfural decarbonylation reaction under the action of a noble metal catalyst to generate crude gas-phase furan;

(3) exchanging heat between the gas phase from the decarbonylation reactor and the gas phase from the furfural vaporization tower, then entering the upper part of a quenching tower, enabling unreacted furfural to enter the bottom of the quenching tower, and returning the tower bottom liquid of the quenching tower to the furfural vaporization tower;

(4) the gas phase in the quenching tower enters a crude product tank for gas-liquid separation after heat exchange and deep cooling, the gas phase in the crude product tank enters an absorption tower, a small amount of furan in the gas phase is absorbed by furfural, and the gas phase discharged from the absorption tower is treated in a tail gas treatment working section;

(5) and (3) rectifying the liquid phase in the crude product groove in a rectifying tower, and controlling the temperature of the rectifying tower to be 50-77 ℃ and the pressure to be 0.1-0.2 Mpa to obtain qualified fine furan.

4. The method for preparing furan by gas-phase decarbonylation of furfural according to claim 1, characterized in that: the noble metal catalyst in the step (2) is palladium chloride or platinum chloride.

5. The method for preparing furan by gas-phase decarbonylation of furfural according to claim 1, characterized in that: the quenching tower adopts finished furan for heat exchange quenching, and tower bottom liquid at the bottom of the quenching tower flows into the furfural vaporization tower by the potential difference.

6. The method for preparing furan by gas-phase decarbonylation of furfural according to claim 1, characterized in that: and (4) the absorption liquid in the absorption tower in the step (4) is furfural.

7. The method for preparing furan by gas-phase decarbonylation of furfural according to claim 1, characterized in that: the deep cooling temperature in the step (4) is 5-10 ℃.

8. A process for the vapor-phase decarbonylation of furfural to produce furan according to any one of claims 1 to 7, characterized in that: the feeding amount of the hydrogen is 50-60 Nm³/h。

9. A process for the vapor-phase decarbonylation of furfural to produce furan according to any one of claims 1 to 7, characterized in that: the purity of the refined furan obtained by the rectification in the step (5) is 99-99.5%.

Technical Field

The invention belongs to the technical field of chemical production, and relates to a device and a method for preparing furan by furfural gas-phase decarbonylation.

Background

Furan is used as an intermediate product of galaxolide, and the current main industrial route method mainly comprises the following steps: preparing furan by decarboxylation of furoic acid; a butadiene oxidation method is adopted; the method for decarbonylating furfural is divided into a gas phase method, a liquid phase method and an oxidative decarbonylation method.

However, in the industrial production of furan ammonium salt, most of the methods for producing furan have the problems of poor catalyst activity, environmental pollution and low furan yield, and currently, the furfural decarbonylation method is mainly used in the industrial production.

The traditional decarbonylation reactor is a multi-section quenching type fixed bed reactor, the reactor is easy to cause local uneven reaction, the temperature rises quickly and flies, the temperature can be cooled only by hydrogen quenching during flying, but hydrogen cannot be supplied in a large amount in a short time, so the slow cooling effect is not good; the furfural is easy to coke on the catalyst at high temperature to generate carbon black, so that the catalyst is bonded and inactivated, the furfural is also easy to oxidize into furoic acid under the condition of oxygen and water, equipment is corroded, a production device needs to be stopped to regenerate the catalyst by burning carbon when the normal catalyst runs for 7-10 days, the treatment needs 3-5 days, and the production benefit is seriously influenced.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provides a device and a method for preparing furan by decarbonylation of furfural in a gas phase.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a device for preparing furan by gas-phase decarbonylation of furfural is characterized by comprising the following equipment:

the top of a furfural vaporization tower (containing a heater) is connected with the bottom of a decarbonylation reactor through a pipeline and an electric heater, the top of the decarbonylation reactor is connected with a quenching tower through a pipeline, the top of the quenching tower is connected with a crude product tank through a pipeline, and the bottom of the crude product tank is connected with a rectifying tower through a pipeline; the bottom of the quenching tower is connected to a furfural vaporization tower through a pipeline, the upper part of the crude product tank is connected to an absorption tower through a pipeline, the bottom of the absorption tower is connected to the furfural vaporization tower through a pipeline, and the top of the rectification tower is connected to the upper part of the quenching tower through a pipeline (condenser) and a fine product tank.

Further, the heater on the furfural vaporization tower is a thin film evaporator.

A method for preparing furan by gas-phase decarbonylation of furfural is characterized by comprising the following steps:

(1) introducing furfural into a heater of a furfural vaporization tower at the rate of 350Kg/h for 300-plus-one, preheating the furfural to the temperature of 110-plus-one and 138 ℃, introducing the furfural into the vaporization tower, and introducing hydrogen into the furfural vaporization tower for protection (reducing the partial pressure of furfural in a gas phase, thereby reducing the vaporization temperature of the furfural, reducing polymerization and coking of the furfural, and reducing the consumption of the furfural), and controlling the temperature in the furfural vaporization tower to be 160-plus-one at 130 ℃;

(2) the gas phase from the furfural vaporization tower enters an electric heater after heat exchange by a heat exchanger (160-;

(3) after heat exchange is carried out between gas phase (crude furan) from the decarbonylation reactor and gas phase from the furfural vaporization tower (80-90 ℃), the gas phase enters the upper part of the quenching tower and absorbs heat with the vaporization of finished furan at the top to carry out heat exchange, so that unreacted furfural enters the bottom of the quenching tower through cooling separation to be recycled, and simultaneously, crude gas phase furan is primarily purified and purified, and the bottom liquid (unreacted furfural) of the quenching tower returns to the furfural vaporization tower;

(4) the gas phase (crude furan) in the quenching tower is subjected to heat exchange and deep cooling and then enters a crude product tank at 5-10 ℃ for gas-liquid separation, the gas phase (uncondensed furan) in the crude product tank enters an absorption tower, a small amount of furan in the gas phase is absorbed by furfural, and the gas phase (furan, hydrogen and carbon monoxide) from the absorption tower is treated by a tail gas treatment working section;

(5) and (3) rectifying the liquid phase (crude furan) in the crude product tank in a rectifying tower at 50-77 ℃ and 0.1-0.2 Mpa to obtain qualified fine furan (with purity of 99-99.5%).

Further, the noble metal catalyst in the step (2) is palladium chloride or platinum chloride.

Further, the quenching tower adopts finished furan for heat exchange quenching, and tower bottom liquid at the bottom of the quenching tower flows into the furfural vaporization tower by the difference of the levels.

Further, the absorption liquid in the absorption tower in the step (4) is furfural.

Further, the feeding amount of the hydrogen is 50-60 Nm³/h。

The device adopts the film evaporator for heating in the furfural vaporization, and simultaneously introduces hydrogen to reduce the partial pressure of furfural in a gas phase, thereby reducing the vaporization temperature of furfural, reducing polymerization and coking of furfural and reducing the consumption of furfural;

the decarbonylation reactor adopts a heat exchange type fixed bed reactor, and heat is transferred by high-temperature heat transfer oil, so that the overall temperature of the reactor is stable at 200 ℃ and 250 ℃, local overheating cannot be formed, side reactions are reduced, high-temperature carbonization of furfural is avoided, the service time of the catalyst is prolonged, and the regeneration times of the catalyst are reduced; the vaporized furfural gas exchanges heat with the gas phase discharged from the decarbonylation reactor and then enters the decarbonylation reactor, so that the full energy recovery is effectively realized;

the extraction cooling tower utilizes the evaporation heat absorption of finished furan to cool the gas phase from the decarbonylation reactor, so that heavy components in the reaction gas are condensed, unreacted furfural and heavy components (dimethyl furan byproducts) generated by side reactions are removed, the tower bottom liquid automatically flows into the furfural evaporation tower by means of the difference of the levels (the phenomenon that the heavy components enter a compressor to cause the loss of furfural materials is avoided), the furfural is evaporated again, and the heavy components are accumulated in the tower kettle and are periodically removed;

pure furan is easy to vaporize under normal pressure because the boiling point of furan is 31.36 ℃; the volume ratio of the furan in the reaction mixed gas is about 25%, so that the majority of furan needs to be condensed at a low temperature of-30 ℃, and the energy consumption is very high; the device used for condensation in the invention is a pressure-resistant 1Mpa tubular heat exchanger, the gas phase from the quenching tower is condensed in a pressurization condensation mode, the condensation temperature can reach-5 ℃, 98 percent of crude furan in the gas phase can be condensed, and the pressure of subsequent tail gas adsorption equipment is reduced;

the invention purifies furan by a rectification tower in a decompression rectification mode, furan can be condensed by using circulating water without using a refrigerant, and reflux liquid flows into the rectification tower by means of a potential difference.

The invention has the advantages that:

1. a small amount of hydrogen is introduced in the furfural vaporization process to reduce the furfural partial pressure in the furfural vaporization process, so that the high-temperature side reaction of furfural is reduced, the conversion rate of furan is improved (from 40-45% to 50-60% in the prior art), the production cost is reduced, and the production efficiency is greatly improved;

2. the activity of the catalyst is improved, the service cycle of the catalyst is prolonged from 7-10 days to 30-60 days, and the corrosion of equipment is avoided;

3. the gas phase of the furfural vaporization tower and the gas phase of the decarbonylation reactor pass through a gas-gas heat exchanger to realize full energy recycling, the energy consumption of furan steam per ton is reduced from 3.5-5 tons to 2-2.5 tons, the temperature is reduced and high-boiling-point impurities are removed by utilizing the property that furan product is easy to vaporize and absorb heat at a low boiling point (31 ℃), so that the reaction efficiency and the material utilization rate are optimized, and the economic benefit of an enterprise is obviously increased;

4. the purity of the furan prepared by rectification is improved from the original 98-98.5% to 99-99.8%.

Drawings

FIG. 1 is a schematic diagram of a device for preparing furan by gas-phase decarbonylation of furfural.

Detailed description of the invention

The invention is further illustrated with reference to fig. 1:

a device and a method for preparing furan by furfural gas-phase decarbonylation comprise the following equipment:

the top of the furfural vaporization tower is connected with a gas-gas heat exchanger through a pipeline, and a pipeline (provided with an electric heater) at an outlet is connected to the bottom of a decarbonylation reactor (a heat exchange type tubular reactor); the top of the decarbonylation reactor is connected with a gas-gas heat exchanger through a pipeline, and an outlet is connected to the upper part of the quenching tower; the top of the quenching tower is connected to the crude product tank through a pipeline and a cooler, and the bottom of the quenching tower is connected to the middle part of the furfural vaporization tower through a pipeline; the upper part of the crude product tank is connected with an absorption tower (absorption liquid is furfural) through a pipeline, the bottom of the absorption tower is connected to the upper part of a furfural vaporization tower through a pipeline, the bottom of the crude product tank is connected with the upper part of a rectifying tower through a pipeline, the bottom of the rectifying tower is connected to a refined product tank through a pipeline and a cooler, and the outlet of the refined product tank is connected to the upper part of a quenching tower; the heater arranged on the furfural vaporization tower is a thin film evaporator, the bottom of the vaporization tower is connected with the thin film evaporator through a pipeline and a pump, and the outlet of the thin film evaporator is connected to the vaporization tower.

A method for preparing furan by furfural gas-phase decarbonylation comprises the following specific implementation steps:

example 1

(1) Introducing furfural into a heater of a furfural vaporization tower at a rate of 320Kg/h, preheating furfural to 120 ℃, introducing furfural into the vaporization tower, and introducing furfural into the furfural vaporization tower at a rate of 55Nm³Introducing hydrogen for protection (reducing the partial pressure of furfural in a gas phase, thereby reducing the vaporization temperature of furfural, reducing polymerization and coking of furfural and reducing the consumption of furfural), and controlling the temperature in a furfural vaporization tower to be 145 ℃;

(2) the gas phase from the furfural vaporization tower is subjected to heat exchange by a heat exchanger (180 ℃) and then enters an electric heater to be heated to 290 ℃, and then enters a decarbonylation reactor, and is fed into the decarbonylation reactor at 55Nm³Introducing hydrogen for protection, controlling the temperature in the decarbonylation reactor to be 300 ℃ and the pressure to be 0.02Mpa, and carrying out the decarbonylation reaction of the furfural under the action of a noble metal catalyst (palladium chloride) to generate crude gas-phase furan;

(3) exchanging heat between the gas phase (crude furan) from the decarbonylation reactor and the gas phase from the furfural vaporization tower at 85 ℃, then entering the upper part (unreacted furfural enters the bottom part of the quenching tower) of the quenching tower (furan heat exchange is adopted in the quenching tower), and returning the tower bottom liquid (unreacted furfural) of the quenching tower to the furfural vaporization tower;

(4) the gas phase (crude furan) in the quenching tower enters a crude product tank for gas-liquid separation after heat exchange and deep cooling (at 8 ℃), the gas phase (uncondensed furan) in the crude product tank enters an absorption tower (the absorption liquid is furfural), a small amount of furan in the gas phase is absorbed by furfural, the gas phase (furan, hydrogen and carbon monoxide) from the absorption tower is treated by a tail gas treatment working section, the liquid phase (crude furan) in the crude product tank enters a rectifying tower for rectification, the temperature and the pressure of the rectifying tower are controlled to be 60 ℃ and 0.15MPa, and qualified fine furan (the purity is 99.3%) is obtained.

Example 2

(1) Introducing furfural into a heater of a furfural vaporization tower at a rate of 300Kg/h, preheating the furfural to 112 ℃, introducing the furfural into the vaporization tower, and introducing the furfural into the furfural vaporization tower at a rate of 52Nm³Introducing hydrogen for protection (reducing the partial pressure of furfural in a gas phase, thereby reducing the vaporization temperature of furfural, reducing polymerization and coking of furfural and reducing the consumption of furfural), and controlling the temperature in a furfural vaporization tower to be 130 ℃;

(2) the gas phase from the furfural vaporization tower is subjected to heat exchange by a heat exchanger (162 ℃) and then enters an electric heater to be heated to 265 ℃, and then enters a decarbonylation reactor, and enters the decarbonylation reactor at 52Nm³Introducing hydrogen for protection, controlling the temperature in the decarbonylation reactor at 265 ℃ and the pressure at 0.01Mpa, and carrying out the decarbonylation reaction of furfural under the action of a noble metal catalyst (palladium chloride) to generate crude gas-phase furan;

(3) exchanging heat between the gas phase (crude furan) from the decarbonylation reactor and the gas phase from the furfural vaporization tower (at 80 ℃), then entering the upper part (unreacted furfural enters the bottom part of the quenching tower) of the quenching tower (furan heat exchange is adopted in the quenching tower), and returning the tower bottom liquid (unreacted furfural) of the quenching tower to the furfural vaporization tower;

(4) the gas phase (crude furan) in the quenching tower enters a crude product tank for gas-liquid separation after heat exchange and deep cooling (at 5 ℃), the gas phase (uncondensed furan) in the crude product tank enters an absorption tower (the absorption liquid is furfural), a small amount of furan in the gas phase is absorbed by furfural, the gas phase (furan, hydrogen and carbon monoxide) from the absorption tower is treated by a tail gas treatment working section, the liquid phase (crude furan) in the crude product tank enters a rectifying tower for rectification, the temperature and the pressure of the rectifying tower are controlled at 52 ℃ and 0.1MPa, and qualified fine furan (the purity is 99%) is obtained.

Example 3

(1) Introducing furfural into a heater of a furfural vaporization tower at 350Kg/h, preheating furfural to 135 deg.C, introducing into the vaporization tower, and introducing into the furfural vaporization tower at 60Nm³Introducing hydrogen for protection (reducing the partial pressure of furfural in gas phase, thereby reducing the vaporization temperature of furfural, reducing polymerization and coking of furfural, reducing the consumption of furfural), controlling the temperature in a furfural vaporization towerAt 155 ℃;

(2) the gas phase from the furfural vaporization tower is subjected to heat exchange by a heat exchanger (220 ℃) and then enters an electric heater to be heated to 330 ℃, and then enters a decarbonylation reactor, and is fed into the decarbonylation reactor at a speed of 60Nm³Introducing hydrogen for protection, controlling the temperature in the decarbonylation reactor at 330 ℃ and the pressure at 0.03Mpa, and carrying out the decarbonylation reaction of furfural under the action of a noble metal catalyst (platinum chloride) to generate crude gas-phase furan;

(3) exchanging heat between gas phase (crude furan) from the decarbonylation reactor and gas phase from the furfural vaporization tower at 90 ℃, then entering the upper part (unreacted furfural enters the bottom part of the quenching tower) of the quenching tower (furan heat exchange is adopted in the quenching tower), and returning the tower bottom liquid (unreacted furfural) of the quenching tower to the furfural vaporization tower;

(4) the gas phase (crude furan) in the quenching tower enters a crude product tank for gas-liquid separation after heat exchange and deep cooling (10 ℃), the gas phase (uncondensed furan) in the crude product tank enters an absorption tower (furfural is used as absorption liquid), a small amount of furan in the gas phase is absorbed by furfural, the gas phase (furan, hydrogen and carbon monoxide) from the absorption tower is treated in a tail gas treatment working section, the liquid phase (crude furan) in the crude product tank enters a rectifying tower for rectification, the temperature and the pressure of the rectifying tower are controlled to be 75 ℃ and 0.2MPa, and qualified fine furan (the purity is 99.5%) is obtained.

The foregoing is merely a preferred embodiment of the invention and is not intended to limit the invention in any manner; those skilled in the art can make numerous possible variations and modifications to the present teachings, or modify equivalent embodiments to equivalent variations, without departing from the scope of the present teachings, using the methods and techniques disclosed above. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments according to the technical essence of the present invention are still within the scope of the protection of the technical solution of the present invention.