CN210096970U

CN210096970U - Furfural multiple-effect reaction rectifying device

Info

Publication number: CN210096970U
Application number: CN201920367447.0U
Authority: CN
Inventors: 李凭力; 李英栋; 邹少兵; 常贺英
Original assignee: TIANJIN SATE CO Ltd
Current assignee: TIANJIN SATE CO Ltd
Priority date: 2019-03-19
Filing date: 2019-03-19
Publication date: 2020-02-21
Anticipated expiration: 2029-03-19

Abstract

The utility model relates to a furfural multiple-effect reaction rectifier unit, including an effect rectifying column and two effect rectifying columns, the tower bottom of an effect rectifying column is provided with one and imitates the coupling reboiler, the top of a tower that an effect rectifying column has set gradually one and has imitated one-level condenser and one and imitate the secondary cooler, the tower bottom of two effect rectifying columns is provided with two effect reboilers, the top of two effect rectifying columns has set gradually two and imitates one-level condenser and two imitate the secondary cooler, the tower bottom of a tower that an effect rectifying column is through pump connection to two effect rectifying column's top of a tower, two imitate one-level condenser through pipe connection to one imitate the coupling reboiler, two imitate the reboiler and connect outside steam inlet. The utility model has the advantages of being scientific and reasonable in design, can reduce the vapor consumption by a wide margin, reduce the quantity and the power consumption of cooling water, can improve rectification purity moreover, improve the furfural yield.

Description

Furfural multiple-effect reaction rectifying device

Technical Field

The utility model belongs to the technical field of chemical material reaction rectification, a furfural rectifier unit is related to, in particular to furfural multiple effect reaction rectifier unit.

Background

Furfural is widely used and is a basic organic chemical raw material, the chemical name is α -furfural, and is a derivative of furan with 2-position hydrogen atom substituted by aldehyde group, which is prepared by co-heating rice bran and dilute acid, so the furfural is called as furfural.

The rectification is a process of separating a mixed liquid composed of components with different volatility into almost pure components by partially vaporizing and partially condensing the mixed liquid in a rectifying tower for many times.

The material in the rectifying tower kettle is heated by a reboiler and then changed into steam to rise into the rectifying tower, and the reflux liquid and the rising steam are contacted with each other on each layer of tower plate to carry out the heat and mass transfer process. Because of temperature difference and concentration difference on the tower plate, the gas phase needs to be partially condensed, so that part of the nonvolatile components in the gas phase is transferred into the liquid phase; the latent heat released by the condensation of the gas phase is transferred to the liquid phase, so that the liquid phase is partially vaporized, and part of the volatile components are transferred into the gas phase. The overall result is that the liquid phase leaving the tray has a lower concentration of volatile components than when entering the tray, and the gas phase leaving the tray has a higher concentration of volatile components than when entering the tray. If the gas-liquid two phases are in contact with the plate for a sufficient time, the gas-liquid two phases leaving the plate are in equilibrium with each other. The similar process as described above is carried out on each plate of the rectifying tower.

In the chemical industry, the rectification process is one of the most energy-consuming unit operations, and since the worldwide energy problem occurs, the energy-saving problem of the rectification process has attracted much attention. The energy saving of the rectification process can be basically started from the following aspects: (1) the heat energy in the rectification process is fully utilized; (2) the requirement of the rectification process on energy is reduced; (3) improving the thermodynamic efficiency of the rectification system; (4) a qualified separation system is employed.

In general, the two operations of reaction and separation are usually carried out in two separate types of equipment. If the two can be combined together and carried out simultaneously in one device, the products or intermediate products generated by the reaction can be separated in time, the yield of the products can be improved, and the reaction heat can be used for separating the products, thereby achieving the purpose of saving energy.

The multi-effect rectification is a heat integrated rectification system which utilizes the latent heat of the steam at the top of a high-pressure tower to provide heat for a reboiler of a low-pressure tower. Compared with a single tower, the multi-effect rectification can greatly improve the utilization rate of energy, save the energy consumption of a rectification device to a greater extent, and the quality of the rectified product is higher than that of single-effect rectification, and the yield is also improved.

The furfural production process mainly comprises a one-step method and a two-step method, and the one-step method adopted in the current industrial production has low furfural yield which is only about 50 percent generally and has serious pollution. The two-step process is to separate the hydrolysis reaction of hemicellulose and the dehydration reaction of pentose into furfural into two independent steps. When biomass is pretreated, because hemicellulose has a non-crystalline structure, low polymerization degree and high branching degree, the hemicellulose can be dissolved and hydrolyzed into pentose from cell walls under proper pretreatment conditions, and furfural can be generated by catalytic reaction of hydrolysate rich in pentose under acidic conditions. In the two-step method, target products in the two reactors are independent, so that fewer byproducts are generated in the reaction process, and the furfural yield is relatively high.

The multi-effect rectification of furfural is a new energy-saving process, and the technology mainly draws high attention of people by low energy consumption, low-grade energy utilization and high-efficiency thermodynamic efficiency. The multi-effect reactive distillation of the furfural takes the first pressurized tower as the first rectifying tower and the second pressurized tower as the second rectifying tower, so that the energy consumption can be greatly reduced and the yield of the furfural is improved.

Through a search for a patent publication, no patent publication that is the same as the present patent application is found.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to overcome prior art's not enough, provide one kind and can reduce the vapor consumption by a wide margin, reduce the quantity and the power consumption of cooling water, improve the furfural multiple effect reaction rectifier unit of furfural yield.

The utility model provides a its technical problem realize through following technical scheme:

a furfural multiple-effect reaction rectifying device is characterized in that: including an effect rectifying column and two effect rectifying column, the tower bottom of an effect rectifying column is provided with one and imitates the coupling reboiler, the top of a tower of an effect rectifying column has set gradually one and imitates primary condenser and one and imitates the secondary cooler, the tower bottom of two effect rectifying column is provided with two effect reboilers, two effect rectifying column's top of a tower has set gradually two and imitates primary condenser and two imitate the secondary cooler, pump connection to is passed through at the bottom of a tower of an effect rectifying column the top of a tower of two effect rectifying column, two imitate primary condenser pass through tube coupling to one imitate the coupling reboiler, two imitate the reboiler and connect outside steam inlet.

And the tower top of the first-effect rectifying tower and the tower bottom of the second-effect rectifying tower are connected to the feeding heat exchanger through pipelines.

And the two-effect first-stage condenser is connected to the one-effect rectifying tower through a pipeline.

And the external steam inlet is connected to the two-effect rectifying tower through a pipeline.

And the steam pressure of the first-effect coupling reboiler and the steam pressure of the second-effect first-order condenser are both 0.4-0.8 MPa, the steam pressure of the second-effect reboiler is 0.6-1.5 MPa, and the steam pressure of the first-effect first-order condenser is 0.3-0.7 MPa.

The utility model discloses an advantage and beneficial effect do:

1. the utility model discloses a furfural multiple-effect reactive distillation, the steam of a first-effect distillation tower can be directly introduced into a tower body through a two-effect first-order condenser, or can be introduced into a tower body after entering a first-effect coupling reboiler; external steam can directly be let in the two-effect rectifying column, also can get in the tower body through the rethread behind the two-effect reboiler, specifically according to the steam volume decision in the multi-effect rectifying device, but the steam admission is nimble to be controlled.

2. The utility model discloses a furfural multiple effect reaction rectification increases the feeding heat exchanger, can promote the entering temperature of material, saves rectification steam quantity.

3. The utility model discloses a furfural multiple effect reaction rectification can improve rectification purity, improves the furfural yield, and the furfural yield can reach more than 75%.

4. The utility model discloses a furfural multiple effect reaction rectification compares with ordinary rectification, not only can reduce the vapor consumption by a wide margin, reduces the quantity and the power consumption of cooling water, improves thermodynamic efficiency for rectification process heat energy can make full use of, reduces rectification process itself and to the needs of energy, through calculating, steam quantity about 8 tons can be practiced thrift to per production one ton furfural.

Drawings

Fig. 1 is a process flow diagram of the present invention.

Description of the reference numerals

The system comprises a 1-effect rectifying tower, a 2-double-effect rectifying tower, a 3-feeding heat exchanger, a 4-double-effect primary condenser, a 5-double-effect secondary cooler, a 6-double-effect reboiler, a 7-pump, an 8-first-effect primary condenser, a 9-first-effect secondary cooler and a 10-first-effect coupling reboiler.

Detailed Description

The present invention will be described in further detail with reference to specific examples, which are provided for illustrative purposes only, and are not intended to be limiting, and the scope of the present invention should not be limited thereby.

A multi-effect reaction rectifying device for furfural is characterized in that: the tower bottom of the first-effect rectifying tower is provided with a first-effect coupling reboiler 10, the tower top of the first-effect rectifying tower is sequentially provided with a first-effect first-stage condenser 8 and a first-effect second-stage cooler 9, the tower bottom of the second-effect rectifying tower is provided with a second-effect reboiler 6, the tower top of the second-effect rectifying tower is sequentially provided with a second-effect first-stage condenser 4 and a second-effect second-stage cooler 5, the tower bottom of the first-effect rectifying tower is connected to the tower top of the second-effect rectifying tower through a pump, the tower top of the first-effect rectifying tower is communicated with a pentose solution, the tower top of the second-effect rectifying tower is provided with a tower bottom liquid from the first-effect rectifying tower, the first-effect coupling reboiler of the first-effect rectifying tower is connected to the second-effect first-stage condenser through a pipeline, and the second-effect reboiler at the tower bottom.

The device also comprises a feeding heat exchanger 3, wherein the top of the first-effect rectifying tower and the bottom of the second-effect rectifying tower are connected to the feeding heat exchanger through pipelines.

The utility model discloses a working process does:

the pentose solution entering the top of the first-effect rectifying tower accounts for 10 percent by mass, the catalyst sulfuric acid accounts for 0.5 percent by mass, and simultaneously the catalyst sulfuric acid also contains a small amount of furfural, the mass fraction of furfural is 0.7 percent, and the balance of water, the mass fraction of furfural is 88.7 percent. The temperature of the pentose solution is 90 ℃, the pentose solution is preheated to 140 ℃ by a feeding heat exchanger and then enters the top of a first-effect rectifying tower, and the feeding flow is 10000 kg/h. The feeding pressure of the first-effect rectifying tower is 0.5MPa, the number of theoretical plates is 10, the pressure at the top of the tower is 0.4MPa, the pressure drop is 5kPa, the first-effect rectifying tower is heated by directly feeding steam into the bottom of the tower, the heating steam is 160 ℃, the steam pressure is 0.52MPa, the heating steam comes from a condenser at the top of the second-effect rectifying tower, the steam flow is 3100kg/h, the temperature at the top of the first-effect rectifying tower is 151.9 ℃, the temperature at the bottom of the tower is 152.5 ℃, and pentose is partially converted into furfural under the action of a catalyst after the reaction of the first-effect rectifying tower.

The majority of furfural produced in the single-effect rectifying tower is extracted from the tower top in the form of furfural aqueous solution, and then the furfural enters a furfural refining section, wherein the mass flow rate of the furfural extraction is 357.9 kg/h. After the reaction and rectification of the first-effect rectifying tower, the water solution produced at the bottom of the tower contains 22.8kg/h (mass fraction is 0.3%) of furfural and 514.4kg/h (mass fraction is 6%) of pentose, and the materials at the bottom of the first-effect rectifying tower enter a second-effect rectifying tower through a pump.

The theoretical plate number of the double-effect rectifying tower 2 is 10, the pressure at the top of the tower is 0.7MPa, the pressure drop of the whole tower is 5kPa, the temperature at the top of the tower is 170.2 ℃, and the temperature at the bottom of the tower is 170.5 ℃. The two-effect rectifying tower is directly heated by external saturated steam, the steam temperature is 175.1 ℃, the pressure is 0.8MPa, and the flow of the steam is 3000 kg/h. The majority of the rest pentose is converted into furfural in the two-effect rectifying tower, furfural is extracted from the top of the two-effect rectifying tower in the form of furfural water solution, and then the furfural enters a furfural refining section, wherein the mass flow rate of the extracted furfural is 298.4 kg/h. And the residual aqueous solution containing a small amount of furfural (mass fraction of 0.2%) and pentose (mass fraction of 0.9%) enters a feeding preheater, passes through a feeding heat exchanger and then returns to a hydrolysis section.

Although the embodiments of the present invention and the accompanying drawings are disclosed for illustrative purposes, those skilled in the art will appreciate that: various substitutions, changes and modifications are possible without departing from the spirit and scope of the present invention and the appended claims, and therefore, the scope of the present invention is not limited to the disclosure of the embodiments and the accompanying drawings.

Claims

1. A furfural multiple-effect reaction rectifying device is characterized in that: including an effect rectifying column and two effect rectifying column, the tower bottom of an effect rectifying column is provided with one and imitates the coupling reboiler, the top of a tower of an effect rectifying column has set gradually one and imitates primary condenser and one and imitates the secondary cooler, the tower bottom of two effect rectifying column is provided with two effect reboilers, two effect rectifying column's top of a tower has set gradually two and imitates primary condenser and two imitate the secondary cooler, pump connection to is passed through at the bottom of a tower of an effect rectifying column the top of a tower of two effect rectifying column, two imitate primary condenser pass through tube coupling to one imitate the coupling reboiler, two imitate the reboiler and connect outside steam inlet.

2. The multi-effect reaction rectification device for furfural according to claim 1 is characterized in that: the tower top of the first-effect rectifying tower and the tower bottom of the second-effect rectifying tower are connected to the feeding heat exchanger through pipelines.

3. The multi-effect reaction rectification device for furfural according to claim 1 is characterized in that: the two-effect first-stage condenser is connected to the one-effect rectifying tower through a pipeline.

4. The multi-effect reaction rectification device for furfural according to claim 1 is characterized in that: and the external steam inlet is connected to the two-effect rectifying tower through a pipeline.

5. The multi-effect reaction rectification device for furfural according to claim 1 is characterized in that: the steam pressure of the first-effect coupling reboiler and the steam pressure of the second-effect first-order condenser are both 0.4-0.8 MPa, the steam pressure of the second-effect reboiler is 0.6-1.5 MPa, and the steam pressure of the first-effect first-order condenser is 0.3-0.7 MPa.