CN111621320A

CN111621320A - Pyrolysis product grading separation method and multi-inner-tower rectifying device

Info

Publication number: CN111621320A
Application number: CN202010368695.4A
Authority: CN
Inventors: 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
Original assignee: Energy Research Institute of Shandong Academy of Sciences
Current assignee: Energy Research Institute of Shandong Academy of Sciences
Priority date: 2020-05-02
Filing date: 2020-05-02
Publication date: 2020-09-04

Abstract

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.

Description

Pyrolysis product grading separation method and multi-inner-tower rectifying device

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.

Example 1: as shown in fig. 1, a multi-inner-tower rectification device is composed of an outer rectification tower 102 and seven inner rectification towers arranged inside the outer rectification tower 102, wherein the inner rectification towers are arranged at different height positions inside the outer rectification tower 102, the uppermost inner rectification tower is named as a first inner rectification tower 1031, and is named as a second inner rectification tower 1032, a third inner rectification tower 1033, a fourth inner rectification tower 1034, a fifth inner rectification tower 1035, a sixth inner rectification tower 1036 and a seventh inner rectification tower 1037 in sequence from bottom to top; the side wall of the outer rectifying tower 102 is provided with a feeding hole 104, the top of the outer rectifying tower 102 is provided with a top gas outlet 101, the bottom of the outer rectifying tower 102 is provided with a bottom discharging hole 105, the upper part of the outer rectifying tower 102 is provided with a reflux inlet 111, and the lower part is provided with a reboiler return port 120.

The top of the outer rectifying tower 102 is provided with a condenser 106 and a reflux tank 108 behind the condenser 106, the reflux tank 108 is provided with a noncondensable gas port 107 and a product discharge pipeline, the product discharge pipeline is divided into two paths, one path is provided with a top product valve 109, and the other path is provided with a top reflux pump 110 and is connected with a reflux inlet 111.

The tower bottom of the outer rectifying tower 102 is provided with a reboiler 121, a pipeline behind a discharge port 105 at the tower bottom of the outer rectifying tower 102 is divided into two paths, one path is provided with a tower bottom discharge pump 122, and the other path is connected with a reboiler return port 120 after passing through the reboiler 121.

The top of the inner rectifying tower is closed and provided with an inner rectifying tower gas outlet 113, the bottom of the inner rectifying tower is closed and provided with an inner rectifying tower liquid outlet 117, the side wall of the inner rectifying tower is provided with an inner rectifying tower liquid inlet 112, a liquid distributor 118 is arranged above each inner rectifying tower liquid inlet 112 in the outer rectifying tower 102, and the liquid distributors 118 can play a role in liquid distribution and gas redistribution; the liquid inlet 112 of the inner rectifying tower is communicated with a liquid outlet pipe 119 of a liquid distributor 118 at the upper part through a pipeline. The gas outlet 113 of the inner rectifying tower is of an inverted U-shaped pipe structure, plays a role of liquid seal and prevents liquid phase from entering the inner rectifying tower; the liquid outlet 117 of the inner rectifying tower is of a U-shaped pipe structure, so that gas phase is prevented from entering the inner rectifying tower.

As shown in fig. 2, the inner rectification column is a dividing wall rectification column, that is, a dividing wall 116 is arranged in the inner rectification column, and the inner rectification column is divided into 6 parts by the dividing wall 116, including a common rectification zone i, a common stripping zone vi, and a feeding section and a side line withdrawing section which are separated by the dividing wall 116, wherein the feeding section and the side line withdrawing section can be divided into a feeding rectification section ii, a side line withdrawing rectification section iii, a feeding stripping section iv and a side line withdrawing stripping section v; the feeding section of the inner rectifying tower is provided with a feeding distributor 201, the side line withdrawing section of the inner rectifying tower is provided with a side line withdrawing port 114 in the middle of the side wall, and the side line withdrawing port 114 is connected with a side line withdrawing pipe 115; one end of the side draw pipe 115 is connected with the side draw distributor 202 in the inner rectifying tower, and the other end passes through the tower wall of the outer rectifying tower 102 and extends to the outside of the outer rectifying tower 102.

The height of the outer rectifying tower 102 is 6 meters, the inner diameter is 0.22 meter, stainless steel theta net ring packing with the diameter and the height of 4 mm is filled, the top of the packing section is 0.4 meter away from the top of the outer rectifying tower 102, and the bottom of the packing section is 1.5 meters away from the bottom of the outer rectifying tower 102; the feed inlet 104 of the outer rectification column 102 is 0.6 m higher than the lower end of the packing section of the outer rectification column 102; the height of the inner rectifying tower is 0.9 meter, the inner diameter is 0.042 meter, stainless steel theta net ring packing with the diameter and the height of 4 mm is filled, the top of the packing section is 0.02 meter away from the top of the outer rectifying tower 102, and the bottom of the packing section is 0.10 meter away from the bottom of the outer rectifying tower 102; the top of the seventh internal rectifying tower 1037 is higher than the lower end of the packing section of the external rectifying tower 102 by 1.15 meters, the top of the sixth internal rectifying tower 1036 is higher than the top of the seventh internal rectifying tower 1037 by 0.4 meter, the top of the fifth internal rectifying tower 1035 is higher than the top of the sixth internal rectifying tower 1036 by 0.4 meter, the top of the fourth internal rectifying tower 1034 is higher than the top of the fifth internal rectifying tower 1035 by 0.3 meter, the top of the third internal rectifying tower 1033 is higher than the top of the fourth internal rectifying tower 1034 by 0.3 meter, the top of the second internal rectifying tower 1032 is higher than the top of the third internal rectifying tower 1033 by 0.3 meter, and the top of the first internal rectifying tower 1031 is higher than the top of the second internal rectifying tower 1032 by 0.3 meter; the liquid distributor 118 is 0.2 meters higher than the inner rectification column liquid inlet 112 of the next lower adjacent inner rectification column.

The liquid inlet 112 of the inner rectifying tower is 0.35 meter higher than the lower end of the packing section of the inner rectifying tower, and the side draw outlet 114 is 0.35 meter higher than the lower end of the packing section of the inner rectifying tower; the dividing wall 116 has a height of 0.35 m and a width of 0.042 m and a lower end 0.2 m higher than the lower end of the packing section of the inner rectification column.

The liquid distributor 118 is a disk-type orifice flow distributor, as shown in fig. 4, and includes a cylinder 403 with a bottom plate 402, 8 gas risers 401 are uniformly arranged on the bottom plate 402 around the center of the circle, and a spraying hole 404 and a guiding hole 405 are further arranged, wherein the guiding hole 405 is connected with the liquid outlet pipe 119 of the liquid distributor 118. The base plate 402 is circular with a diameter of 0.22 meters; the diameter of the cylinder 403 is 0.22 m, and the height is 0.05 m; the diameter and height of the gas lift pipe 401 are 0.042 m and 0.03 m respectively, and the distance between the circle center of the gas lift pipe 401 and the circle center of the bottom plate 402 is 0.06 m. The diameter of the spraying holes 404 is 0.005 m, and the distance between the centers of the holes is 0.02 m; the centre of a circle of the diversion hole 405 is located at the centre of a circle of the bottom plate 402, and the diameter of the diversion hole 405 is 0.04 m.

The feed distributor 201 is a disk-type orifice flow distributor, as shown in fig. 5, and includes a cylinder 403 having a bottom plate 402, and a gas riser 401 and spray holes 404 are disposed on the bottom plate 402. The bottom plate 402 is semicircular, and the diameter of the bottom plate is 0.042 m; the diameter of the cylinder 403 is 0.042 m, and the height is 0.03 m; 4 gas risers 401 are evenly arranged on the bottom plate 402 around the circle center, the diameter and the height of the gas risers 401 are respectively 0.006 meter and 0.02 meter, and the distance between the circle center of the gas risers 401 and the circle center of the bottom plate 402 is 0.016 meter. The diameter of the spraying holes 404 is 0.004 m, and the center distance of the holes is 0.012 m.

The side production distributor 202 is a disc-type hole flow distributor, as shown in fig. 6, and comprises a cylinder 403 with a bottom plate 402, wherein a gas lift pipe 401, a spraying hole 404 and a diversion hole 405 are arranged on the bottom plate 402, and the diversion hole 405 is connected with the side production pipe 115. The bottom plate 402 is semicircular, and the diameter of the bottom plate is 0.042 m; the diameter of the cylinder 403 is 0.042 m, and the height is 0.03 m; 4 gas risers 401 are evenly arranged on the bottom plate 402 around the circle center, the diameter and the height of the gas risers 401 are respectively 0.006 meter and 0.02 meter, and the distance between the circle center of the gas risers 401 and the circle center of the bottom plate 402 is 0.016 meter. The diameter of the spraying holes 404 is 0.004 m, and the center distance of the holes is 0.012 m. The circle center of the diversion hole 405 is located on the symmetry axis of the semicircular bottom plate 402, and the distance from the circle center of the bottom plate 402 is 0.0065 m.

The pine wood pyrolysis product is separated by stages by adopting the multi-internal rectifying tower rectifying device to prepare the bio-oil, the pine wood powder with 20-50 meshes (the water content is 10%) is taken as a raw material, the raw material is fed into a spiral pyrolysis reactor (with the length of 1500 mm and the inner diameter of 15 mm) through a spiral feeding system at the speed of 10 kg/h, the pyrolysis temperature is 550 ℃, and a solid carbon product generated by pyrolysis directly enters a carbon box to be collected; the pyrolysis gas product enters a cooler for cooling to 240 ℃ after being dedusted by a cyclone separator, is added into the outer rectifying tower 102 from a feed inlet 104 of the outer rectifying tower 102 for rectification, a liquid phase reaching the bottom of the outer rectifying tower 102 is discharged from a discharge outlet 105 at the bottom of the tower, a part of the liquid phase enters a reboiler 121 for vaporization and returns to the outer rectifying tower 102 through a reboiler return tower outlet 120, and a residual liquid phase part of the liquid phase is discharged out of the outer rectifying tower 102 through a tower bottom discharge pump 122; the reboiler 121 is an electrically heated reboiler, and the liquid phase temperature at the bottom of the outer rectifying column 102 is stabilized at 260 ℃ by controlling the heating power of the reboiler 121.

Discharging light components reaching the top of the outer rectifying tower 102 through a top gas outlet 101, condensing the light components through a condenser 106, then feeding the condensed light components into a reflux tank 108, discharging non-condensable gas through a non-condensable gas port 107, discharging a liquid phase from the reflux tank 108, discharging one path of the liquid phase through a top product valve 109 to serve as a product, and refluxing the other path of the liquid phase into the outer rectifying tower 102 through a top reflux pump 110 and a reflux liquid inlet 111 in sequence, wherein the reflux ratio is controlled to be 2: 1, and the temperature at the top of the outer rectifying tower 102 is 80 ℃; the condenser 106 is a water-cooled condenser, and the temperature of the condensate after passing through the condenser 106 is reduced to 45 ℃ by controlling the flow rate of the inlet water.

After a liquid phase at a certain height is discharged from a liquid outlet pipe 119 of a liquid distributor 118 of the outer rectifying tower 102, the liquid phase enters the inner rectifying tower from a liquid inlet 112 of the inner rectifying tower through a pipeline for rectification, a light component and a part of intermediate components move towards the upper part of the tower, a heavy component and a part of intermediate components move towards the lower part of the tower, the separation of the light component and the intermediate components is completed in a common rectification area, and the light component is discharged from a gas outlet 113 of the inner rectifying tower in a gas state and returns to the outer rectifying tower 102 for continuous rectification; the common stripping zone finishes the separation of the middle component and the heavy component, the heavy component is discharged from a liquid outlet 117 of the inner rectifying tower in a liquid state and enters the outer rectifying tower 102 for continuous rectification, the middle component is extracted from a side line extraction outlet 114 in a liquid state and then is discharged out of the outer rectifying tower 102 through a side line extraction pipe 115, and the fractions extracted from the side lines of each inner rectifying tower are collected. The distillation range of the sample was determined according to GB/T6536-2010 petroleum product atmospheric distillation characterisation.

The distillate discharged from the product valve 109 at the top of the outer rectifying tower 102 is colorless liquid, the distillate volume at 30-90 ℃ in the distillation range determination process accounts for 92.8% of the sample volume, the sample is stored for 24 hours at 30 ℃, and the viscosity at 30 ℃ is increased by 3.5%; the distillate discharged from the first internal rectifying tower 1031 is colorless liquid, the distillate volume at 90-110 ℃ accounts for 91.9% of the sample volume in the distillation range determination process, and the viscosity rises by 6.2% when the sample is heated at 80 ℃ for 24 hours and at 40 ℃; the distillate discharged from the second internal rectifying tower 1032 is colorless liquid, the distillate volume at 110-130 ℃ accounts for 90.5% of the sample volume in the distillation range determination process, the sample is heated at 80 ℃ for 24 hours, and the viscosity at 40 ℃ is increased by 8.4%; the distillate discharged from the third internal rectifying tower 1033 is light yellow liquid, the distillate volume at 130-150 ℃ accounts for 90.0% of the sample volume in the process of measuring the distillation range, the sample is heated for 24 hours at 80 ℃, and the viscosity at 40 ℃ is increased by 10.6%; the fraction discharged from the fourth internal rectifying tower 1034 is a light yellow liquid, the distillation volume at 150-170 ℃ in the distillation range determination process accounts for 89.1% of the sample volume, the heating is carried out for 24 hours at 80 ℃, and the viscosity at 40 ℃ is increased by 12.9%; the fraction discharged from the fifth internal rectifying tower 1035 is light yellow liquid, the distillation volume at 170-190 ℃ accounts for 88.7% of the sample volume in the distillation range determination process, the heating is carried out for 24 hours at 80 ℃, and the viscosity at 40 ℃ is increased by 13.1%; the distillate discharged from the sixth internal rectifying tower 1036 is light yellow liquid, the distillate volume at 190-210 ℃ accounts for 88.0% of the sample volume in the distillation range determination process, the heating is carried out for 24 hours at 80 ℃, and the viscosity at 40 ℃ is increased by 15.8%; the distillate discharged from the seventh internal rectifying tower 1037 is light yellow liquid, the distillate volume at 210-240 ℃ accounts for 86.5% of the sample volume in the process of measuring the distillation range, the heating is carried out for 24 hours at 80 ℃, and the viscosity rises by 16.3% at 40 ℃; the material discharged from the discharge pump 122 at the bottom of the outer rectifying tower 102 is black viscous liquid, and the distillation volume at 30-240 ℃ in the distillation range determination process accounts for 10.3% of the volume of the sample.

The bio-oil prepared by the conventional pyrolysis and refining method is inferior in stability, for example, in the literature (zhang wei, zhao zhuang, zheng anqing, etc. bio-oil storage stability experimental study [ J ]. journal of fuel chemistry, 2012, 40 (2): 184 (189)) the bio-oil prepared by the conventional pyrolysis and refining method using pine as a raw material is heated at 80 ℃ for 24 hours, and the viscosity measured at 40 ℃ is increased by about 113%. Also for example, in the literature (Oasmaa, Kuoppala E. Fast Pyrolysis of forest Residue.3. Storage Stability of Liquid Fuel [ J ]. Energy & Fuels, 2003, 17 (4): 1075 and 1084.) the bio-oil prepared by conventional Pyrolysis and refining methods using pine as a raw material was heated at 80 ℃ for 24 hours, and the viscosity increase measured at 40 ℃ was about 89 to 143%. The biological oil obtained by the embodiment has obviously smaller viscosity increase amplitude after being heated, which shows that the invention can obtain more stable biological oil products.

In the embodiment, one rectifying tower is used for completing the separation tasks which can be completed by a plurality of common rectifying towers, 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, heat required by vaporization of low-boiling-point fractions in the inner rectifying towers is heat released by condensation of high-boiling-point fractions in the outer rectifying towers, and energy coupling utilization is realized.

In this embodiment, the inner rectifying tower adopts a dividing wall rectifying tower, a liquid phase at a certain height enters the inner rectifying tower to be rectified during operation, a light component and a heavy component 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, an intermediate component (a target component) is collected from the side line of the inner rectifying tower, high boiling point substances generated by the thermosensitive bio-oil in the outer rectifying tower can be separated into fractions with corresponding boiling ranges, meanwhile, stabilization of the bio-oil is realized, and high-quality boiling-range distillate oil with clear cutting is obtained.

Example 2: the same parts of this embodiment as embodiment 1 will not be described again, but the differences are: the top of the second internal rectification column 1032 is 0.4 m higher than that of the third internal rectification column 1033, and the second internal rectification column 1032 is filled with stainless steel theta net ring packing with the diameter and height of 5 mm.

The distillate discharged from the product valve 109 at the top of the outer rectifying tower 102 is colorless liquid, the distillate volume at 30-90 ℃ in the distillation range determination process accounts for 92.7% of the sample volume, the sample is stored for 24 hours at 30 ℃, and the viscosity at 30 ℃ is increased by 3.4%; the distillate discharged from the first internal rectifying tower 1031 is colorless liquid, the distillate volume at 90-110 ℃ accounts for 91.7% of the sample volume in the distillation range determination process, and the viscosity rises by 6.1% when the sample is heated at 80 ℃ for 24 hours at 40 ℃; the distillate discharged from the second internal rectifying tower 1032 is colorless liquid, the distillate volume at 110-130 ℃ accounts for 90.7% of the sample volume in the distillation range determination process, the sample is heated at 80 ℃ for 24 hours, and the viscosity at 40 ℃ is increased by 8.2%; the distillate discharged from the third internal rectifying tower 1033 is light yellow liquid, the distillate volume at 130-150 ℃ accounts for 90.0% of the sample volume in the process of measuring the distillation range, the sample is heated for 24 hours at 80 ℃, and the viscosity at 40 ℃ is increased by 10.5%; the fraction discharged from the fourth internal rectifying tower 1034 is a light yellow liquid, the distillation volume at 150-170 ℃ in the distillation range determination process accounts for 89.5% of the sample volume, the heating is carried out for 24 hours at 80 ℃, and the viscosity at 40 ℃ is increased by 12.6%; the fraction discharged from the fifth internal rectifying tower 1035 is light yellow liquid, the distillation volume at 170-190 ℃ accounts for 88.8% of the sample volume in the distillation range determination process, the heating is carried out for 24 hours at 80 ℃, and the viscosity at 40 ℃ is increased by 13.6%; the distillate discharged from the sixth internal rectifying tower 1036 is light yellow liquid, the distillate volume at 190-210 ℃ accounts for 87.0% of the sample volume in the distillation range determination process, the heating is carried out for 24 hours at 80 ℃, and the viscosity at 40 ℃ is increased by 15.6%; the distillate discharged from the seventh internal rectifying tower 1037 is light yellow liquid, the distillate volume at 210-240 ℃ accounts for 86.7% of the sample volume in the process of measuring the distillation range, the heating is carried out for 24 hours at 80 ℃, and the viscosity rises by 16.1% at 40 ℃; the material discharged from the discharge pump 122 at the bottom of the outer rectifying tower 102 is black viscous liquid, and the distillation volume at 30-240 ℃ in the distillation range determination process accounts for 10.1% of the volume of the sample.

This example shows that adjusting one of the inner rectifying towers of the multi-inner-tower rectifying device has little influence on other operating parameters, and has good operation flexibility, dynamic characteristics and controllability.

Example 3: the same parts of this embodiment as embodiment 1 will not be described again, but the differences are: the utility model provides a many inner tower rectifier unit, it comprises outer rectifying tower 102 and 2 inner rectifying towers that set up in outer rectifying tower 102 inside, and inner rectifying tower arranges in the different height position of outer rectifying tower 102 inside, and the inner rectifying tower of higher authority is named first inner rectifying tower 1031, and the inner rectifying tower of lower authority is named second inner rectifying tower 1032. The feed inlet 104 of the outer rectification column 102 is 0.8 m higher than the lower end of the packing section of the outer rectification column 102; the top of the second inner rectification column 1032 is 1.6 meters higher than the lower end of the packing section of the outer rectification column 102, and the top of the first inner rectification column 1031 is 1.5 meters higher than the top of the second inner rectification column 1032.

The multiple inner rectifying tower rectifying devices are adopted to fractionate pine pyrolysis products to prepare the bio-oil. The distillate discharged from the product valve 109 at the top of the outer rectifying tower 102 is colorless liquid, the distillate volume at 30-90 ℃ accounts for 90.2% of the sample volume in the distillation range determination process, the sample is stored for 24 hours at 30 ℃, and the viscosity at 30 ℃ is increased by 10.8%; the fraction discharged from the first internal rectifying tower 1031 is light yellow liquid, the distillation volume at 90-150 ℃ in the distillation process accounts for 85.4% of the sample volume, and the viscosity rises by 18.5% when the sample is heated at 80 ℃ for 24 hours at 40 ℃; the distillate discharged from the second internal rectifying tower 1032 is light yellow liquid, the distillate volume at 150-220 ℃ accounts for 85.6% of the sample volume in the distillation range determination process, the heating is carried out for 24 hours at 80 ℃, and the viscosity at 40 ℃ is increased by 20.1%; the material discharged from the discharge pump 122 at the bottom of the outer rectifying tower 102 is black viscous liquid, and the distillation volume at 30-240 ℃ in the distillation range determination process accounts for 12.7% of the volume of the sample.

Example 4: the same parts of this embodiment as embodiment 1 will not be described again, but the differences are: the utility model provides a many inner tower rectifier unit, it comprises outer rectifying tower 102 and 3 inner rectifying towers that set up in outer rectifying tower 102 inside, and inner rectifying tower arranges in the different height position of outer rectifying tower 102 inside, and the inner rectifying tower of the top is named first inner rectifying tower 1031, and down names second inner rectifying tower 1032, third inner rectifying tower 1033 in proper order. The feed inlet 104 of the outer rectification column 102 is 0.7 m higher than the lower end of the packing section of the outer rectification column 102; the top of the third inner rectification column 1033 at the bottom is 1.3 m higher than the lower end of the packing section of the outer rectification column 102, the top of the second inner rectification column 1032 is 0.9 m higher than the top of the third inner rectification column 1033, and the top of the first inner rectification column 1031 is 1.0 m higher than the top of the second inner rectification column 1032. The liquid distributor 118 is 0.3 meters higher than the inner rectification column liquid inlet 112 of the next lower adjacent inner rectification column.

The multi-inner rectifying tower rectifying device is adopted to fractionate and separate the pyrolysis products of the corn straws to prepare the bio-oil, and the corn straw powder with the water content of 10 percent and the mesh of 20 to 50 is used as a raw material. The pyrolysis gas product enters a cooler for cooling to 220 ℃ after being dedusted by a cyclone separator, is added into the external rectifying tower 102 from the feeding port 104 of the external rectifying tower 102 for rectification, and is fed into the external rectifying tower 102 through the reboiler returning port 120 at the speed of 1.15 kg/h. The reflux ratio is controlled to be 1.5: 1, the temperature of the top of the outer rectifying tower 102 is 60 ℃, and the temperature of the condensate is reduced to 40 ℃ after passing through the condenser 106.

The distillate discharged from the product valve 109 at the top of the outer rectifying tower 102 is colorless liquid, the distillate volume at 30-130 ℃ accounts for 92.8% of the sample volume in the distillation range determination process, the sample is stored for 24 hours at 30 ℃, and the viscosity at 30 ℃ is increased by 5.4%; the distillate discharged from the first internal rectifying tower 1031 is colorless liquid, the distillate volume at 120-160 ℃ accounts for 90.5% of the sample volume in the distillation range determination process, and the viscosity rises by 7.0% when the sample is heated at 80 ℃ for 24 hours at 40 ℃; the distillate discharged from the second internal rectifying tower 1032 is light yellow liquid, the distillate volume at 160-200 ℃ accounts for 88.9% of the sample volume in the distillation range determination process, the sample is heated for 24 hours at 80 ℃, and the viscosity at 40 ℃ is increased by 8.1%; the distillate discharged from the third internal rectifying tower 1033 is light yellow liquid, the distillation volume at 180-240 ℃ accounts for 88.0% of the sample volume in the distillation range determination process, the sample is heated for 24 hours at 80 ℃, and the viscosity at 40 ℃ is increased by 10.5%; the material discharged from the discharge pump 122 at the bottom of the outer rectifying tower 102 is black viscous liquid, and the distillation volume at 30-240 ℃ in the distillation range determination process accounts for 8.9% of the volume of the sample.

Example 5 (comparative): the same parts of this embodiment as those of embodiment 4 will not be described again, except that: the first internal rectification column 1031, the second internal rectification column 1032 and the third internal rectification column 1033 are not provided with the partition wall 116, the side draw distributor 202 and the side draw outlet 114 inside, and a pipeline is arranged after the liquid discharge outlet 117 of the internal rectification column to extend to the outside of the external rectification column 102 through the column wall of the external rectification column 102.

In the rectification process, after a liquid phase at a certain height is discharged from a liquid outlet pipe 119 of a liquid distributor 118 of the outer rectification tower 102, the liquid phase enters the inner rectification tower from a liquid inlet 112 of the inner rectification tower through a pipeline for rectification, light components and a part of intermediate components move towards the upper part of the tower and are discharged from a gas outlet 113 of the inner rectification tower in a gas state and return to the outer rectification tower 102 for continuous rectification, heavy components and a part of intermediate components move towards the lower part of the tower and are discharged from a liquid outlet 117 of the inner rectification tower to the outside of the outer rectification tower 102 through a pipeline in a liquid state, and each fraction is collected. The liquid distributor 118 is 0.4 meters higher than the inner rectification column liquid inlet 112 of the next lower adjacent inner rectification column.

The distillate discharged from the product valve 109 at the top of the outer rectifying tower 102 is colorless liquid, the distillate volume at 30-130 ℃ accounts for 83.1% of the sample volume in the distillation range determination process, the sample is stored for 24 hours at 30 ℃, and the viscosity at 30 ℃ is increased by 12.8%; the distillate discharged from the first internal rectifying tower 1031 is colorless liquid, the distillation volume at 120-160 ℃ accounts for 81.7% of the sample volume in the distillation range determination process, and the viscosity rises by 16.8% when the sample is heated at 80 ℃ for 24 hours at 40 ℃; the distillate discharged from the second internal rectifying tower 1032 is light yellow liquid, the distillate volume at 160-200 ℃ accounts for 81.0% of the sample volume in the distillation range determination process, the sample is heated for 24 hours at 80 ℃, and the viscosity at 40 ℃ is increased by 14.9; the distillate discharged from the third internal rectifying tower 1033 is light yellow liquid, the distillation volume at 180-240 ℃ accounts for 80.2% of the sample volume in the distillation range determination process, the sample is heated for 24 hours at 80 ℃, and the viscosity at 40 ℃ is increased by 14.5%; the material discharged from the discharge pump 122 at the bottom of the outer rectifying tower 102 is black viscous liquid, and the distillation volume at 30-240 ℃ in the distillation range determination process accounts for 9.6% of the volume of the sample.

In this example, the internal rectifying column was not provided with a partition wall, and the distillation range distribution of the obtained fraction was wider than that of the example 4, and the viscosity rise after heating was large and the thermal stability was slightly poor.

Example 6: the same parts of this embodiment as embodiment 1 will not be described again, but the differences are: the multi-inner-rectifying-tower rectifying device is composed of an outer rectifying tower 102 and 5 inner rectifying towers arranged inside the outer rectifying tower 102, wherein the inner rectifying towers are arranged at different height positions inside the outer rectifying tower 102, the uppermost inner rectifying tower is named as a first inner rectifying tower 1031, and the uppermost inner rectifying tower is named as a second inner rectifying tower 1032, a third inner rectifying tower 1033, a fourth inner rectifying tower 1034 and a fifth inner rectifying tower 1035 in sequence. The top of the lowermost fifth internal rectifying tower 1035 is 1.2 meters higher than the lower end of the packing section of the external rectifying tower 1034, the top of the fourth internal rectifying tower 1034 is 0.5 meters higher than the top of the fifth internal rectifying tower 1035, the top of the third internal rectifying tower 1033 is 0.5 meters higher than the top of the fourth internal rectifying tower 1034, the top of the second internal rectifying tower 1032 is 0.5 meters higher than the top of the third internal rectifying tower 1033, and the top of the first internal rectifying tower 1031 is 0.5 meters higher than the top of the second internal rectifying tower 1032.

As shown in fig. 3, the inner rectifying tower is formed by a tube bundle consisting of a plurality of round tubes with the inner diameter of 0.015 meter, stainless steel theta-net ring packing with the diameter and height of 4 mm is filled in the round tubes, the distance between two adjacent tubes is 5mm, a box-type feeder 301 is arranged at the feeding section of the inner rectifying tower, an air outlet distributor 302 is arranged at the top of the inner rectifying tower, the top of the air outlet distributor 302 is closed and is provided with an air outlet 113 of the inner rectifying tower; the bottom of the inner rectifying tower is provided with a liquid collector 306, the bottom of the liquid collector 306 is closed and is provided with an inner rectifying tower liquid outlet 117; in the side draw section, one end of a side draw pipe 115 is connected with a box-type side draw device 304 in the inner rectifying tower, and the other end of the side draw pipe 115 penetrates through the tower wall of the outer rectifying tower 102 and extends to the outside of the outer rectifying tower 102; a public rectification gas-liquid distributor 303 is arranged at the bottom of the public rectification area I, and a public stripping gas-liquid distributor 305 is arranged at the top of the public stripping area VI; the upper end of the tube bundle of the public rectification area I is communicated with an air outlet distributor 302 of the inner rectification tower, and the lower end of the tube bundle is communicated with a public rectification gas-liquid distributor 303 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 303 of the inner rectification tower, and the lower end of the tube bundle is communicated with a box-type feeder 301 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 303 of the inner rectifying tower, and the lower end of the tube bundle is communicated with a box-type side extractor 304 of the inner rectifying tower; the upper end of the tube bundle of the feeding stripping section IV is communicated with a box-type feeder 301 of the inner rectifying tower, and the lower end of the tube bundle is communicated with a public stripping gas-liquid distributor 305 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 304 of the inner rectifying tower, and the lower end of the tube bundle is communicated with a common stripping gas-liquid distributor 305 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 305 of the inner rectifying tower, and the lower end of the tube bundle is communicated with a liquid collector 306 of the inner rectifying tower; the liquid collector 306 is closed at the bottom and is provided with a liquid outlet.

The distance between the box-type feeder 301 and the public rectification gas-liquid distributor 303 is 0.2 m, and 5 tubes are arranged; the distance between the box-type feeder 301 and the public stripping gas-liquid distributor 305 is 0.15 meter, and 5 tubes are arranged; the distance between the box-type side collector 304 and the public rectification gas-liquid distributor 303 is 0.25 m, and 3 tubes are arranged; the distance between the box-type side collector 304 and the public stripping gas-liquid distributor 305 is 0.1 meter, and 3 tubes are arranged; the distance between the public rectification gas-liquid distributor 303 and the outlet distributor 302 is 0.35 m, and 8 pipes are arranged; the distance between the common stripping gas-liquid distributor 305 and the liquid collector 306 is 0.2 m, and 8 tubes are arranged.

The box-type feeder 301, the outlet distributor 302, the common rectification gas-liquid distributor 303, the box-type side collector 304, the common stripping gas-liquid distributor 305 and the liquid collector 306 are cylinders with closed tops and closed bottoms, and the height of the cylinder is 0.02 m. In the embodiment, the liquid phase volume ratio of the liquid phase flowing out of the common rectification gas-liquid distributor 303 and entering the feeding section and the side line extraction section of the inner rectification tower is 5: 3; the volume of liquid phase flowing out of the side draw outlet 114 accounted for 60% of the total volume of liquid phase passing through the box side draw 304.

The biological oil is prepared by separating poplar wood chip pyrolysis products in a grading way by adopting the rectifying devices with multiple internal rectifying towers, and 20-50 meshes of poplar wood chips (with the water content of 5%) are used as raw materials.

The pyrolysis gas product enters a cooler for cooling to 220 ℃ after being dedusted by a cyclone separator, is added into the external rectifying tower 102 from the feeding port 104 of the external rectifying tower 102 for rectification, and is fed into the external rectifying tower 102 through the reboiler returning port 120 at the speed of 1.05 kg/h. The reflux ratio is controlled to be 1.5: 1, the temperature of the top of the outer rectifying tower 102 is 75 ℃, and the temperature of the condensate is reduced to 50 ℃ after passing through the condenser 106.

The distillate discharged from the product valve 109 at the top of the outer rectifying tower 102 is colorless liquid, the distillate volume at 30-115 ℃ in the distillation range determination process accounts for 92.9% of the sample volume, the sample is stored for 24 hours at 30 ℃, and the viscosity at 30 ℃ is increased by 4.9%; the distillate discharged from the first internal rectifying tower 1031 is colorless liquid, the distillate volume at 110-135 ℃ accounts for 91.7% of the sample volume in the distillation range determination process, and the viscosity rises by 11.5% when the sample is heated at 80 ℃ for 24 hours at 40 ℃; the distillate discharged from the second internal rectifying tower 1032 is light yellow liquid, the distillate volume at 135-160 ℃ accounts for 89.0% of the sample volume in the distillation range determination process, the sample is heated for 24 hours at 80 ℃, and the viscosity at 40 ℃ is increased by 11.7%; the fraction discharged from the third internal rectifying tower 1033 is light yellow liquid, the distillation volume at 160-185 ℃ accounts for 86.3% of the sample volume in the distillation range determination process, the sample is heated at 80 ℃ for 24 hours, and the viscosity at 40 ℃ is increased by 14.1%; the fraction discharged from the fourth internal rectifying tower 1034 is a pale yellow liquid, the distillation volume at 185-210 ℃ in the distillation range determination process accounts for 85.1% of the sample volume, the heating is carried out at 80 ℃ for 24 hours, and the viscosity at 40 ℃ is increased by 14.5%; the fraction discharged from the fifth internal rectifying tower 1035 is light yellow liquid, the distillation volume at 210-240 ℃ accounts for 83.9% of the sample volume in the distillation range determination process, the heating is carried out for 24 hours at 80 ℃, and the viscosity at 40 ℃ is increased by 14.8%; the material discharged from the discharge pump 122 at the bottom of the outer rectifying tower 102 is black viscous liquid, the distillation volume at 30-240 ℃ in the distillation range determination process accounts for 7.5% of the sample volume, and the viscosity is increased by 19.8% after heating at 80 ℃ for 24 hours.

Example 7: the same parts of this embodiment as embodiment 1 will not be described again, but the differences are: the multi-inner-rectifying-tower rectifying device comprises an outer rectifying tower 102 and 9 inner rectifying towers arranged inside the outer rectifying tower 102, wherein the inner rectifying towers are filled with stainless steel theta net ring packing with the diameter and the height of 6 mm, the inner rectifying towers are arranged at different height positions inside the outer rectifying tower 102, the uppermost inner rectifying tower is named as a first inner rectifying tower 1031, and the uppermost inner rectifying tower is named as a second inner rectifying tower 1032, a third inner rectifying tower 1033, a fourth inner rectifying tower 1034, a fifth inner rectifying tower 1035, a sixth inner rectifying tower 1036, a seventh inner rectifying tower 1037, an inner rectifying tower 1038 and an inner rectifying tower 1039 in sequence. The top of the bottommost inner rectifying tower 1039 is higher than the lower end of the packing section of the outer rectifying tower 102 by 1.1 m, the top of the inner rectifying tower 1038 is higher than the top of the inner rectifying tower 1039 by 0.3 m, the top of the seventh inner rectifying tower 1037 is higher than the top of the inner rectifying tower 1038 by 0.25 m, the top of the sixth inner rectifying tower 1036 is higher than the top of the seventh inner rectifying tower 1037 by 0.25 m, the top of the fifth inner rectifying tower 1035 is higher than the top of the sixth inner rectifying tower 1036 by 0.3 m, the top of the fourth inner rectifying tower 1034 is higher than the top of the fifth inner rectifying tower 1035 by 0.3 m, the top of the third inner rectifying tower 1033 is higher than the top of the fourth inner rectifying tower 1034 by 0.35 m, the top of the second inner rectifying tower 1032 is higher than the top of the third inner rectifying tower 1033 by 0.35 m, and the top of the first inner rectifying tower 1031 is higher than the top of the second inner rectifying tower 1032 by 0.35 m.

The biological oil is prepared by separating the pyrolysis product of the mixture of the pine pyrolysis crude oil and the pine by stages by adopting the multi-inner rectifying tower rectifying device, and the preparation process of the pine pyrolysis crude oil comprises the following steps: taking 20-50 mesh pine wood powder (water content is 5%) as a raw material, feeding the pine wood powder into a spiral pyrolysis reactor (with the length of 1500 mm and the inner diameter of 15 mm) through a spiral feeding system at the speed of 10 kg/h, wherein the pyrolysis temperature is 550 ℃, and directly feeding a solid carbon product generated by pyrolysis into a carbon box for collection; and (3) dedusting the pyrolysis gas product by a cyclone separator, then cooling the pyrolysis gas product to 80 ℃ in a two-stage spray tower, discharging the liquid phase from the bottom of the tower, and collecting the pyrolysis crude oil of the corn straws, wherein the water content is measured to be 0.362 g/g, the density is measured to be 1.1 g/ml, and the acid value is measured to be 42.28 mg KOH/g. Mixing the prepared pine pyrolysis crude oil and pine powder (with the water content of 5 percent and the particle size of 20-50 meshes) according to the mass ratio of 1: 5, then performing pyrolysis as a raw material, dedusting pyrolysis gas products by a cyclone separator, then cooling the products in a cooler to 220 ℃, adding the products into an external rectifying tower 102 from a feeding hole 104 of the external rectifying tower 102 for rectification, and feeding ethanol into the external rectifying tower 102 through a reboiler returning hole 120 at the speed of 1.1 kg/h. The liquid phase temperature at the bottom of the outer rectifying tower 102 is stabilized at 240 ℃ by controlling the heating power of the reboiler 121, the top temperature of the outer rectifying tower 102 is 80 ℃, and the temperature of the condensate is reduced to 40 ℃ after passing through the condenser 106.

The distillate discharged from the product valve 109 at the top of the outer rectifying tower 102 is colorless liquid, the distillate volume at 30-100 ℃ in the distillation range determination process accounts for 92.8% of the sample volume, the sample is stored for 24 hours at 30 ℃, and the viscosity at 30 ℃ is increased by 3.5%; the distillate discharged from the first internal rectifying tower 1031 is colorless liquid, the distillate volume at 90-105 ℃ accounts for 85.4% of the sample volume in the distillation range determination process, and the viscosity rises by 13.0% when the sample is heated at 80 ℃ for 24 hours at 40 ℃; the distillate discharged from the second internal rectifying tower 1032 is light yellow liquid, the distillate volume at 105-120 ℃ accounts for 84.0% of the sample volume in the distillation range determination process, the sample is heated at 80 ℃ for 24 hours, and the viscosity at 40 ℃ is increased by 13.5%; the fraction discharged from the third internal rectifying tower 1033 is light yellow liquid, the distillation volume at 120-135 ℃ in the distillation process accounts for 83.3% of the sample volume, the sample is heated at 80 ℃ for 24 hours, and the viscosity at 40 ℃ is increased by 13.9%; the fraction discharged from the fourth internal rectifying tower 1034 is a light yellow liquid, the distillation volume at 130-145 ℃ in the distillation range determination process accounts for 83.2% of the sample volume, the heating is carried out for 24 hours at 80 ℃, and the viscosity at 40 ℃ is increased by 14.3%; the fraction discharged from the fifth internal rectifying tower 1035 is light yellow liquid, the distillation volume at 140-155 ℃ accounts for 82.8% of the volume of the sample in the distillation range determination process, the sample is heated at 80 ℃ for 24 hours, and the viscosity at 40 ℃ is increased by 14.8%; the distillate discharged from the sixth internal rectifying tower 1036 is light yellow liquid, the distillate volume at 150-165 ℃ accounts for 82.1% of the sample volume in the distillation range determination process, the sample is heated at 80 ℃ for 24 hours, and the viscosity at 40 ℃ is increased by 15.3%; the distillate discharged from the seventh internal rectifying tower 1037 is light yellow liquid, the distillate volume at 160-175 ℃ accounts for 81.5% of the sample volume in the process of measuring the distillation range, the heating is carried out for 24 hours at 80 ℃, and the viscosity rises by 16.0% at 40 ℃; the distillate discharged from the inner rectifying tower 1038 is light yellow liquid, the distillate volume at 170-185 ℃ accounts for 80.4% of the sample volume in the process of measuring the distillation range, the sample is heated for 24 hours at 80 ℃, and the viscosity at 40 ℃ is increased by 16.7%; the distillate discharged from the inner rectifying tower 1039 is light yellow liquid, the distillate volume at 180-200 ℃ accounts for 80.1% of the sample volume in the distillation range determination process, and the viscosity rises by 17.1% when the sample is heated for 24 hours at 80 ℃; the material discharged from the discharge pump 122 at the bottom of the outer rectifying tower 102 is black viscous liquid, the distillation volume at 30-220 ℃ in the distillation range determination process accounts for 6.1% of the sample volume, and the viscosity is increased by 18.7% after heating at 80 ℃ for 24 hours at 40 ℃.

Example 8: the same parts of this embodiment as those of embodiment 6 will not be described again, except that: the commercial gasoline for the automobile is fractionated by adopting a multi-inner-tower rectifying device, the gasoline is heated to 50 ℃, and then is added into an outer rectifying tower 102 from a feed inlet 104 of the outer rectifying tower 102 at a speed of 4.0 kg/h for rectification, the liquid phase temperature at the bottom of the outer rectifying tower 102 is stabilized at 180 ℃, the reflux ratio is controlled at 2: 1, the temperature at the top of the outer rectifying tower 102 is 60 ℃, and the temperature of a condensate is reduced to 40 ℃ after passing through a condenser 106. No ethanol is fed to the external rectification column 102 via the reboiler return port 120.

The distillate discharged from the product valve 109 at the top of the outer rectifying tower 102 is colorless liquid, and the distillate volume at 30-65 ℃ in the distillation range determination process accounts for 94.2% of the sample volume; the distillate discharged from the first internal rectifying tower 1031 is colorless liquid, and the distillate volume at 60-80 ℃ in the distillation range determination process accounts for 93.1% of the sample volume; the distillate discharged from the second internal rectifying tower 1032 is colorless liquid, and the distillate volume at 80-100 ℃ in the distillation range determination process accounts for 91.5% of the sample volume; the distillate discharged from the third internal rectifying tower 1033 is colorless liquid, and the distillate volume at 100-120 ℃ in the distillation range determination process accounts for 88.6% of the sample volume; the distillate discharged from the fourth internal rectifying tower 1034 is colorless liquid, and the distillate volume at 120-150 ℃ in the distillation range determination process accounts for 87.8% of the sample volume; the fraction discharged from the fifth internal rectifying tower 1035 is light yellow liquid, and the distillation volume at 150-180 ℃ in the distillation range determination process accounts for 87.5% of the sample volume; the material discharged from the discharge pump 122 at the bottom of the outer rectifying tower 102 is a light yellow liquid, and the distillation volume at 30-180 ℃ in the distillation range determination process accounts for 8.2% of the sample volume.

Claims

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.