阅读说明：本技术 热解产物分级分离方法及多内塔精馏装置 (Pyrolysis product grading separation method and multi-inner-tower rectifying device ) 是由 金付强 陈雷 华栋梁 伊晓路 孙来芝 许海朋 李岩 谢新苹 杨双霞 于 2020-05-02 设计创作，主要内容包括：一种热解产物分级分离方法及多内塔精馏装置,多内精馏塔精馏装置由外精馏塔及设置于外精馏塔内部的至少2个内精馏塔组成,内精馏塔为分隔壁精馏塔或者由多根管组成的管束构成,能够解决已有多组分混合物分离技术能耗高、热敏性混合物分离纯度低的问题,用于生物质等热解产物的分级分离。(A pyrolysis product fractionation method and a multi-inner-tower rectifying device are provided, the multi-inner-tower rectifying device is composed of an outer rectifying tower and at least 2 inner rectifying towers arranged in the outer rectifying tower, the inner rectifying tower is a dividing wall rectifying tower or a tube bundle composed of a plurality of tubes, the problems of high energy consumption and low separation purity of heat-sensitive mixtures in the existing multicomponent mixture separation technology can be solved, and the multi-inner-tower rectifying device is used for fractionation of pyrolysis products such as biomass.)

1. A multi-inner-tower rectifying device is characterized by comprising an outer rectifying tower and at least 2 inner rectifying towers arranged in the outer rectifying tower, wherein the inner rectifying towers are arranged at different height positions in the outer rectifying tower; the side wall of the outer rectifying tower is provided with a feeding hole, the top of the outer rectifying tower is provided with a tower top gas outlet, the bottom of the outer rectifying tower is provided with a tower bottom discharging hole, the upper part of the outer rectifying tower is provided with a reflux inlet, and the lower part of the outer rectifying tower is provided with a reboiler return port; the top of the outer rectifying tower is provided with a condenser and a reflux tank behind the condenser, the reflux tank is provided with a noncondensable gas port and a product discharge pipeline, the product discharge pipeline is divided into two paths, one path is provided with a tower top product valve, and the other path is provided with a tower top reflux pump and is connected with a reflux liquid inlet; a reboiler is arranged at the bottom of the outer rectifying tower, a pipeline behind a discharge port at the bottom of the outer rectifying tower is divided into two paths, one path is provided with a tower bottom discharge pump, and the other path is connected with a tower return port of the reboiler after passing through the reboiler; the top of the inner rectifying tower is closed and is provided with an air outlet of the inner rectifying tower, and the air outlet of the inner rectifying tower is of an inverted U-shaped pipe structure, so that the liquid seal effect is realized, and a liquid phase is prevented from entering the inner rectifying tower; the bottom of the inner rectifying tower is closed and is provided with an inner rectifying tower liquid outlet which is of a U-shaped pipe structure and prevents gas phase from entering the inner rectifying tower; the side wall of the inner rectifying tower is provided with an inner rectifying tower liquid inlet, and a liquid distributor is arranged above each inner rectifying tower liquid inlet in the outer rectifying tower; the liquid inlet of the inner rectifying tower is connected with a liquid outlet pipe of a liquid distributor at the upper part through a pipeline.

2. The multi-internal-tower rectifying apparatus according to claim 1, wherein the liquid distributor is a disk-type orifice flow distributor comprising a cylinder body with a bottom plate, the bottom plate is provided with a gas lift pipe, a spraying hole and a diversion hole, wherein the diversion hole is connected with a liquid outlet pipe of the liquid distributor.

3. The multiple internal column rectification apparatus of claim 1 wherein the number of internal rectification columns is at least 2.

4. The multi-inner-tower rectifying apparatus according to claim 3, wherein the number of the inner rectifying towers is 3 to 9.

5. The multi-internal-tower rectifying device as claimed in claim 1, wherein the internal rectifying tower is a dividing wall rectifying tower, i.e. a dividing wall is arranged in the internal rectifying tower, the internal rectifying tower is divided into 6 parts by the dividing wall, a common rectifying section I, a common stripping section VI, and a feeding section and a side line extraction section which are separated by the dividing wall, wherein the feeding section and the side line extraction section can be divided into a feeding rectifying section II, a side line extraction rectifying section III, a feeding stripping section IV and a side line extraction stripping section V; the feeding section of the inner rectifying tower is provided with a feeding distributor, the side line extraction section of the inner rectifying tower is provided with a side line extraction port in the middle of the side wall, and the side line extraction port is connected with a side line extraction pipe; one end of the side extraction pipe is connected with the side extraction distributor in the inner rectifying tower, and the other end of the side extraction pipe penetrates through the tower wall of the outer rectifying tower and extends to the outside of the outer rectifying tower.

6. The multiple internal column rectification apparatus of claim 5 wherein the feed distributor is a tray orifice flow distributor comprising a barrel having a floor with risers and spray orifices disposed therein.

7. The multiple internal column rectification apparatus as claimed in claim 5 wherein the side draw distributor is a disk orifice flow distributor comprising a cylinder with a bottom plate having a draft tube, spray holes and deflector holes disposed therein, wherein the deflector holes are connected to the side draw tube.

8. The multi-inner-tower rectifying device according to claim 1, wherein the inner rectifying tower is formed by a tube bundle consisting of a plurality of tubes, the feeding section of the inner rectifying tower is provided with a box-type feeder, the top of the inner rectifying tower is provided with an outlet distributor, the top of the outlet distributor is closed and is provided with an outlet of the inner rectifying tower; the bottom of the inner rectifying tower is provided with a liquid collector, the bottom of the liquid collector is closed, and a liquid outlet of the inner rectifying tower is arranged; one end of a lateral line extraction pipe is connected with a box-type lateral extractor in the inner rectifying tower, and the other end of the lateral line extraction pipe penetrates through the tower wall of the outer rectifying tower and extends to the outside of the outer rectifying tower; a public rectification gas-liquid distributor is arranged at the bottom of the public rectification area I, and a public stripping gas-liquid distributor is arranged at the top of the public stripping area VI; the upper end of a tube bundle of the public rectification area I is communicated with an air outlet distributor of the inner rectification tower, and the lower end of the tube bundle is communicated with a public rectification gas-liquid distributor of the inner rectification tower; the upper end of the tube bundle of the feeding rectification section II is communicated with a common rectification gas-liquid distributor of the inner rectification tower, and the lower end of the tube bundle is communicated with a box-type feeder of the inner rectification tower; the upper end of a tube bundle of the side line extraction rectifying section III is communicated with a common rectifying gas-liquid distributor of the inner rectifying tower, and the lower end of the tube bundle is communicated with a box-type side extractor of the inner rectifying tower; the upper end of a tube bundle of the feeding stripping section IV is communicated with a box-type feeder of the inner rectifying tower, and the lower end of the tube bundle is communicated with a public stripping gas-liquid distributor of the inner rectifying tower; the upper end of a tube bundle of the side draw stripping section V is communicated with a box-type side draw device of the inner rectifying tower, and the lower end of the tube bundle is communicated with a public stripping gas-liquid distributor of the inner rectifying tower; the upper end of the tube bundle of the common stripping area VI is communicated with a common stripping gas-liquid distributor of the inner rectifying tower, and the lower end of the tube bundle is communicated with a liquid collector of the inner rectifying tower; the bottom of the liquid collector is closed and is provided with a liquid outlet.

9. A method for carrying out pyrolysis product fractionation by using the rectifying device with multiple internal rectifying towers is characterized by comprising the following steps: adding the pyrolysis product into an outer rectifying tower from a feed inlet of the outer rectifying tower for rectification, discharging a liquid phase reaching the bottom of the outer rectifying tower through a discharge outlet at the bottom of the tower, feeding a part of the liquid phase into a reboiler for vaporization, returning the part of the liquid phase to the outer rectifying tower through a tower return outlet of the reboiler, and discharging the remaining liquid phase part out of the outer rectifying tower through a discharge pump at the bottom of the tower; discharging light components reaching the top of the outer rectifying tower through a top gas outlet, condensing the light components through a condenser, then feeding the light components into a reflux tank, discharging non-condensable gas through a non-condensable gas outlet, discharging a liquid phase from the reflux tank, discharging the liquid phase as a product through a top product valve, and sequentially refluxing the other path of the liquid phase into the outer rectifying tower through a top reflux pump and a reflux liquid inlet; after a liquid phase at a certain height is discharged from a liquid outlet pipe of a liquid distributor of the outer rectifying tower, the liquid phase enters the inner rectifying tower from a liquid inlet of the inner rectifying tower through a pipeline for rectification, a light component and a part of middle components move towards the upper part of the tower, a heavy component and a part of middle components move towards the lower part of the tower, the separation of the light component and the middle components is completed in a common rectification area, and the light component is discharged from a gas outlet of the inner rectifying tower in a gas state and returns to the outer rectifying tower for continuous rectification; the common stripping area finishes the separation of the middle component and the heavy component, the heavy component is discharged from the liquid outlet of the inner rectifying tower in a liquid state and enters the outer rectifying tower for continuous rectification, the middle component is extracted from the side line extraction outlet in a liquid state and then is discharged out of the outer rectifying tower through the side line extraction pipe, and the fractions extracted from the side line of each inner rectifying tower are collected.

10. The method as claimed in claim 9, wherein the distillation tower is returned to the reboiler, and methanol or ethanol is introduced into the distillation tower.

Technical Field

The scheme relates to the field of chemical industry, in particular to a pyrolysis product grading separation method and a multi-inner-tower rectifying device, which are used for mass transfer separation processes in the fields of chemical industry, oil refining, petrifaction, environmental protection and the like.

Background

With the increase of global energy consumption and the aggravation of environmental pollution, renewable energy is more and more valued by people. The biomass energy has the characteristics of environmental friendliness, wide raw material source, renewability and the like, and becomes an important force for international energy transformation. The pyrolysis technology can convert biomass (straw, fruit shell, wood chip, etc.) with low energy density into bio-oil with high energy density, and the preparation and application of the bio-oil are concerned based on the importance of liquid fuel in the whole energy structure. The bio-oil has very complex composition and high oxygen content, and the determined components are hundreds of types, almost comprise all oxygen-containing organic matters, such as ether, ester, aldehyde, ketone, phenol, acid, alcohol and the like, and have the characteristics of high viscosity, high water content, poor stability and high corrosivity, thereby seriously hindering the application and popularization of the bio-oil. If the large-scale fine separation of the bio-oil can be realized, a large number of products with multiple purposes can be obtained, and the revolution of raw materials and energy industry is hopeful to be brought.

Conventional bio-oil refining and separating means comprise distillation, solvent separation, centrifugal separation, chromatographic separation, membrane separation, supercritical extraction, molecular distillation and the like, wherein liquid bio-oil products are obtained and then refined and separated, which undoubtedly increases the complexity of the technology and the process, for example, in the traditional distillation process, the separation effect of heat-sensitive bio-oil is not ideal and the problems of coking and aging exist, although the boiling point of bio-oil can be reduced by adopting reduced pressure distillation, the heat-sensitive bio-oil still can generate various reactions in the whole rectifying tower to generate high-boiling-point substances, so that the product yield is still not ideal, and the composition of the obtained fraction is still very complex; high boiling point substances generated by heat-sensitive bio-oil appear in each fraction obtained by adopting a multi-lateral line fractionation process; molecular distillation can be operated at lower temperatures, but has low molecular distillation production capacity, high equipment investment and complex composition of the obtained fractions. If the biomass pyrolysis gas is directly separated into several products with different purposes and relatively stable properties in the condensation process of the biomass pyrolysis gas, and then refined and separated according to the properties of the products, the separation cost and the utilization difficulty of the bio-oil are greatly reduced.

The fractional condensation technology is a method for condensing biomass pyrolysis gas step by step according to different boiling points of components, can realize primary fractional separation of bio-oil from the source, obviously improves the quality of the obtained bio-oil, but only adopts simple fractional condensation, so that the composition of the obtained bio-oil is still very complex, the utilization difficulty is still large, and a more precise bio-oil refining and separating technology is urgently needed to be developed.

Rectification is a chemical separation unit operation widely applied, but the energy consumption in the rectification process is very large, and the improvement of the energy utilization rate in the rectification process is always a research hotspot.

The internal thermal coupling technology of the rectifying tower is an ideal energy-saving method, and novel devices are continuously developed, wherein the internal energy integration rectifying tower can ensure that the rectifying section is operated under higher pressure than the stripping section by installing a compressor and a throttle valve between the rectifying section and the stripping section, so that enough heat exchange temperature difference is generated, and heat is transferred to the stripping section at a corresponding position from the rectifying tower section. The Japanese successively develops a concentric cylinder type and a multi-concentric cylinder binding type thermally coupled rectifying tower; however, the concentric cylinder type thermally coupled distillation column has a simpler structure, but still does not solve the problem of small original internal thermally coupled heat transfer area, and the multi-concentric cylinder bundled internal thermally coupled distillation column has a larger heat transfer area, but has a complex structure and high cost, and is difficult to popularize and apply in practice. Patent 200910087709.9 discloses an internal thermally coupled distillation column, wherein three external heat exchangers are used to realize thermal coupling between the rectifying section and the stripping section, and one external heat exchanger is used to exchange heat between the top of the rectifying section and the top of the stripping section, so as to realize the operation of the internal thermally coupled distillation column without external heat regeneration; however, the internal thermally coupled distillation column includes four external heat exchangers and two column bodies, and the equipment is large in size and high in cost. 201010195101.0 discloses a liquid parallel-flow composite tower, which comprises a tower body divided into an inner rectifying tower and an outer rectifying tower, the inner rectifying tower is sleeved in the outer rectifying tower, each of the inner rectifying tower and the outer rectifying tower is provided with a tower plate corresponding to the cross section of the inner rectifying tower, the tower plates are provided with a liquid descending system capable of enabling liquid on each layer of tower plate to flow in the same direction, the patent eliminates a liquid retention area on the traditional tower plate, increases effective mass transfer area, increases processing capacity and improves mass transfer efficiency of the tower plates, but the heat of the liquid parallel-flow composite tower is provided by a reboiler at the bottom of the tower, the energy consumption is high, the heat utilization rate is low, and in order to achieve better rectifying effect, the tower height is generally higher, the installation and construction difficulty is high, the maintenance and repair are difficult, then 201420863590.6 and 201420871708.X, a thermal coupling jet parallel-flow tower is disclosed, which comprises a tower body and a plurality of layers of continuous mass transfer tower plates, the tower body comprises the inner rectifying tower, each layer of continuous mass transfer column plate comprises a column plate provided with an air lifting hole, a cap cover and a liquid descending system, wherein a rectifying section and a stripping section are formed between the inner rectifying tower and the outer rectifying tower through the isolation of the outer wall of the inner rectifying tower, the temperature difference between the stripping section and the rectifying section is effectively utilized to carry out heat exchange and recover heat at the tower wall of the inner rectifying tower, the heat exchange area is increased, the heat dissipation capacity is effectively reduced, and the heat transfer of the stripping section to the rectifying section is enhanced, so that the energy-saving purpose is achieved. However, these techniques are energy-saving methods for rectification developed for simple mixtures, and it is difficult to finely fractionate bio-oil with complex composition.

In addition, the dividing wall rectifying tower is one of the thermocouple rectifying towers, for example, patents 201210172039.2, 201110074332.0 and 201510647969.2 all adopt the dividing wall rectifying tower with a dividing wall, thereby shortening the process flow, reducing the equipment investment, improving the separation efficiency and reducing the separation energy consumption. The dividing wall column technology using a dividing wall is nearly mature at present, but can only be used for simple 3-component separation. Separation of four components and above requires more dividing walls, and the literature (D Dwivedi, IJ Halvorsen, S Skoogest. Control construction for four-product Petlyuk column [ J ]. Chemical Engineering and processing & processing industry, 2013, 67(5): 49-59.) uses a dividing wall rectifying column provided with 3 dividing walls for separation of four components systems of methanol, ethanol, propylene glycol, butanol; patent 201310279930.0 has adopted the baffle tower that has more baffle for separation preparation methylnaphthalene and industry acenaphthene, the wash oil fraction gets into the baffle tower and rectifies, draws forth multistrand product stream from the baffle tower: naphthalene oil, methylnaphthalene, middle-quality wash oil, acenaphthene fraction and heavy wash oil, and the purity and yield of the product are improved. However, the structure and control of the dividing wall rectifying tower adopting two or more dividing walls tend to be complex, and adjusting a certain dividing wall has great influence on other operating parameters, so that the operating elasticity, dynamic characteristics and controllability of the dividing wall rectifying tower are poor, therefore, the number of the dividing walls is limited to 1-6, and is limited to only separating 3-5 component systems, and the high-purity separation of the biological oil with hundreds of components is difficult.

Pyrolysis products of other raw materials such as petroleum, waste plastics, waste rubber, garbage, coal, etc. are complex multi-component mixtures, and need to be separated to improve the added value of the pyrolysis products; in the fields of petroleum, chemical industry, environmental protection and the like, a large number of multi-component mixtures exist, and a separation technology with high efficiency and low consumption is also needed.

Disclosure of Invention

The scheme aims to provide a pyrolysis product grading separation method and a multi-inner-tower rectifying device.

The scheme is realized by the following technical scheme: a multi-inner-tower rectifying device consists of an outer rectifying tower and at least 2 inner rectifying towers arranged in the outer rectifying tower, wherein the inner rectifying towers are arranged at different height positions in the outer rectifying tower; the side wall of the outer rectifying tower is provided with a feeding hole, the top of the outer rectifying tower is provided with a tower top gas outlet, the bottom of the outer rectifying tower is provided with a tower bottom discharging hole, the upper part of the outer rectifying tower is provided with a reflux inlet, and the lower part of the outer rectifying tower is provided with a reboiler return port; the top of the outer rectifying tower is provided with a condenser and a reflux tank behind the condenser, the reflux tank is provided with a noncondensable gas port and a product discharge pipeline, the product discharge pipeline is divided into two paths, one path is provided with a tower top product valve, and the other path is provided with a tower top reflux pump and is connected with a reflux liquid inlet; a reboiler is arranged at the bottom of the outer rectifying tower, a pipeline behind a discharge port at the bottom of the outer rectifying tower is divided into two paths, one path is provided with a tower bottom discharge pump, and the other path is connected with a tower return port of the reboiler after passing through the reboiler; the top of the inner rectifying tower is closed and is provided with an air outlet of the inner rectifying tower, and the air outlet of the inner rectifying tower is of an inverted U-shaped pipe structure, so that the liquid seal effect is realized, and a liquid phase is prevented from entering the inner rectifying tower; the bottom of the inner rectifying tower is closed and is provided with an inner rectifying tower liquid outlet which is of a U-shaped pipe structure and prevents gas phase from entering the inner rectifying tower; the side wall of the inner rectifying tower is provided with an inner rectifying tower liquid inlet, and a liquid distributor is arranged above each inner rectifying tower liquid inlet in the outer rectifying tower; the liquid inlet of the inner rectifying tower is connected with a liquid outlet pipe of a liquid distributor at the upper part through a pipeline.

The liquid distributor adopts a disc type hole flow distributor and comprises a cylinder body with a bottom plate, wherein a gas rising pipe, a spraying hole and a flow guide hole are arranged on the bottom plate, and the flow guide hole is connected with a liquid outlet pipe of the liquid distributor.

The number of the inner rectifying towers is at least 2, preferably 3-9.

The inner rectifying tower is a dividing wall rectifying tower, namely a dividing wall is arranged in the inner rectifying tower, the inner rectifying tower is divided into 6 parts by the dividing wall, a public rectifying area I, a public stripping area VI, and a feeding section and a side line extraction section which are separated by the dividing wall, wherein the feeding section and the side line extraction section can be divided into a feeding rectifying section II, a side line extraction rectifying section III, a feeding stripping section IV and a side line extraction stripping section V; the feeding section of the inner rectifying tower is provided with a feeding distributor, the side line extraction section of the inner rectifying tower is provided with a side line extraction port in the middle of the side wall, and the side line extraction port is connected with a side line extraction pipe; one end of the side extraction pipe is connected with the side extraction distributor in the inner rectifying tower, and the other end of the side extraction pipe penetrates through the tower wall of the outer rectifying tower and extends to the outside of the outer rectifying tower.

The feeding distributor adopts a disc type hole flow distributor and comprises a cylinder body with a bottom plate, wherein a gas lift pipe and spraying holes are arranged on the bottom plate.

The side mining distributor adopts a disc type hole flow distributor and comprises a cylinder body with a bottom plate, wherein a gas rising pipe, a spraying hole and a flow guide hole are arranged on the bottom plate, and the flow guide hole is connected with a side mining pipe.

The inner rectifying tower is formed by a tube bundle consisting of a plurality of tubes, a box-type feeder is arranged at the feeding section of the inner rectifying tower, an air outlet distributor is arranged at the top of the inner rectifying tower, and the top of the air outlet distributor is closed and is provided with an air outlet of the inner rectifying tower; the bottom of the inner rectifying tower is provided with a liquid collector, the bottom of the liquid collector is closed, and a liquid outlet of the inner rectifying tower is arranged; one end of a lateral line extraction pipe is connected with a box-type lateral extractor in the inner rectifying tower, and the other end of the lateral line extraction pipe penetrates through the tower wall of the outer rectifying tower and extends to the outside of the outer rectifying tower; a public rectification gas-liquid distributor is arranged at the bottom of the public rectification area I, and a public stripping gas-liquid distributor is arranged at the top of the public stripping area VI; the upper end of a tube bundle of the public rectification area I is communicated with an air outlet distributor of the inner rectification tower, and the lower end of the tube bundle is communicated with a public rectification gas-liquid distributor of the inner rectification tower; the upper end of the tube bundle of the feeding rectification section II is communicated with a common rectification gas-liquid distributor of the inner rectification tower, and the lower end of the tube bundle is communicated with a box-type feeder of the inner rectification tower; the upper end of a tube bundle of the side line extraction rectifying section III is communicated with a common rectifying gas-liquid distributor of the inner rectifying tower, and the lower end of the tube bundle is communicated with a box-type side extractor of the inner rectifying tower; the upper end of a tube bundle of the feeding stripping section IV is communicated with a box-type feeder of the inner rectifying tower, and the lower end of the tube bundle is communicated with a public stripping gas-liquid distributor of the inner rectifying tower; the upper end of a tube bundle of the side draw stripping section V is communicated with a box-type side draw device of the inner rectifying tower, and the lower end of the tube bundle is communicated with a public stripping gas-liquid distributor of the inner rectifying tower; the upper end of the tube bundle of the common stripping area VI is communicated with a common stripping gas-liquid distributor of the inner rectifying tower, and the lower end of the tube bundle is communicated with a liquid collector of the inner rectifying tower; the bottom of the liquid collector is closed and is provided with a liquid outlet.

The box type feeder, the gas outlet distributor, the common rectification gas-liquid distributor, the box type side collector, the common stripping gas-liquid distributor and the liquid collector are of a cylinder body with a closed top and a closed bottom, but the structure is not limited to the structure, and other devices capable of achieving the functions of collecting and distributing liquid and redistributing gas can be adopted.

The scheme provides a method for carrying out pyrolysis product fractionation by using the rectifying devices with multiple inner rectifying towers, which comprises the following steps: adding the pyrolysis product into an outer rectifying tower from a feed inlet of the outer rectifying tower for rectification, discharging a liquid phase reaching the bottom of the outer rectifying tower through a discharge outlet at the bottom of the tower, feeding a part of the liquid phase into a reboiler for vaporization, returning the part of the liquid phase to the outer rectifying tower through a tower return outlet of the reboiler, and discharging the remaining liquid phase part out of the outer rectifying tower through a discharge pump at the bottom of the tower; discharging light components reaching the top of the outer rectifying tower through a top gas outlet, condensing the light components through a condenser, then feeding the light components into a reflux tank, discharging non-condensable gas through a non-condensable gas outlet, discharging a liquid phase from the reflux tank, discharging the liquid phase as a product through a top product valve, and sequentially refluxing the other path of the liquid phase into the outer rectifying tower through a top reflux pump and a reflux liquid inlet; after a liquid phase at a certain height is discharged from a liquid outlet pipe of a liquid distributor of the outer rectifying tower, the liquid phase enters the inner rectifying tower from a liquid inlet of the inner rectifying tower through a pipeline for rectification, a light component and a part of middle components move towards the upper part of the tower, a heavy component and a part of middle components move towards the lower part of the tower, the separation of the light component and the middle components is completed in a common rectification area, and the light component is discharged from a gas outlet of the inner rectifying tower in a gas state and returns to the outer rectifying tower for continuous rectification; the common stripping area finishes the separation of the middle component and the heavy component, the heavy component is discharged from the liquid outlet of the inner rectifying tower in a liquid state and enters the outer rectifying tower for continuous rectification, the middle component is extracted from the side line extraction outlet in a liquid state and then is discharged out of the outer rectifying tower through the side line extraction pipe, and the fractions extracted from the side line of each inner rectifying tower are collected.

And introducing methanol or ethanol into the rectifying tower through a reboiler return tower opening.

The beneficial effect of this scheme is: (1) the outer rectifying tower is internally provided with a plurality of even tens of inner rectifying towers, the pyrolysis products are correspondingly separated to obtain a plurality of even tens of fractions, and one device is used for realizing fine grading separation of the pyrolysis products, so that the limitation that the dividing wall rectifying tower is only used for separating 3-5 component systems is broken through.

(2) The separation tasks which can be completed by a plurality of common rectifying towers are completed by one rectifying tower, a thermocouple is formed between each inner rectifying tower and each outer rectifying tower, each inner rectifying tower does not need a reboiler and a condenser, the heat required by vaporization of the low-boiling fraction in the inner rectifying tower is the heat released by condensation of the high-boiling fraction in the outer rectifying tower, and energy coupling utilization is realized.

(3) The influence of adjusting one of the internal rectifying towers on other operation parameters is small, and the internal rectifying tower has good operation elasticity, dynamic characteristics and controllability.

(4) The inner rectifying tower adopts a dividing wall rectifying tower, liquid phase at a certain height enters the inner rectifying tower to be rectified during operation, light components and heavy components are respectively discharged from the top and the bottom of the inner rectifying tower and return to the outer rectifying tower to be continuously rectified, intermediate components (target components) are collected from the lateral line of the inner rectifying tower, high boiling point substances generated by thermosensitive bio-oil in the outer rectifying tower can be separated into fractions with corresponding boiling ranges, meanwhile, the stabilization of the bio-oil is realized, and high-quality distillate oil with clear boiling range cutting is obtained.

Drawings

FIG. 1 is a schematic view of a multi-internal-column rectification apparatus. FIG. 2 is a schematic diagram of a structure and a partition of an internal rectifying tower adopting a dividing wall rectifying tower. FIG. 3 is a schematic view of a divided wall column in which the inner column takes the form of a tube bundle. Fig. 4 is a schematic diagram of a disc orifice flow distributor used in a liquid distributor. Fig. 5 is a schematic structural diagram of a disc type hole flow distributor adopted by the feed distributor. Fig. 6 is a schematic structural diagram of a disc-type orifice flow distributor adopted by a side-mining distributor.

In the figure: 101-a top gas outlet; 102-an external rectification column; 1031-a first internal rectification column; 1032-a second internal rectification column; 1033-a third internal rectification column; 1034-a fourth internal rectification column; 1035-a fifth internal rectification column; 1036-a sixth internal rectification column; 1037-a seventh internal rectification column; 104-a feed inlet; 105-bottom discharge hole; 106-a condenser; 107-non-condensing port; 108-reflux tank; 109-overhead product valve; 110-overhead reflux pump; 111-reflux inlet; 112-liquid inlet of inner rectifying tower; 113-an air outlet of the inner rectifying tower; 114-a side draw; 115-sidedraw line; 116-a separation wall; 117-liquid outlet of inner rectifying tower; 118-a liquid dispenser; 119-the outlet pipe of the liquid distributor; 120-reboiler reflux port; 121-a reboiler; 122-a column bottom discharge pump; 201-a feed distributor; 202-side mining distributor; 301-cassette feeder; 302-an outlet gas distributor; 303-common rectification gas-liquid distributor; 304-cartridge lateral miner; 305-common stripping gas-liquid distributor; 306-liquid collector; 401-gas lift pipe; 402-a backplane; 403-cylinder body; 404-spray holes; 405-diversion holes.

Detailed Description

The present invention will be described in more detail below with reference to the accompanying drawings by way of specific embodiments.