WO2019117759A1

WO2019117759A1 - Single-stage method of butadiene production

Info

Publication number: WO2019117759A1
Application number: PCT/RU2018/050159
Authority: WO
Inventors: Виталий Леонидович СУШКЕВИЧ; Андрей Валентинович СМИРНОВ; Ирина Игоревна ИВАНОВА
Original assignee: Общество с ограниченной ответственностью "ЭТБ каталитические технологии" (ООО "ЭТБ КаТ")
Priority date: 2017-12-15
Filing date: 2018-12-06
Publication date: 2019-06-20
Also published as: EA201892713A1; RU2680828C1; EA037702B1

Abstract

The invention relates to gas-phase synthesis of butadiene from ethanol or from a mixture of ethanol and butadiene precursors such as acetaldehyde. A production method includes transforming ethanol, or a mixture of ethanol with acetaldehyde or other butadiene precursors under conditions of continuous and batch feed of raw material of various composition in a reactor with a moving catalyst layer. The invention makes it possible to provide a high yield of butadiene per unit of mass of catalyst and sufficient catalyst service life until regeneration while maintaining heat transfer efficiency during the reaction.

Description

SINGLE-STAGE METHOD FOR BUTADIENE RECEIVING

TECHNICAL FIELD

The invention relates to the field of petrochemistry, the synthesis of basic monomers for rubbers, technologies based on the use of renewable resources. In more detail, the present invention relates to the field of one-step process for the production of butadiene from ethanol on a solid catalyst.

BACKGROUND

The process of obtaining butadiene from ethanol on a solid catalyst is usually carried out on a fixed bed of catalyst at elevated temperature and low pressure. Similar methods are described, for example, in the following sources: KR 2014/050 531 A; US20160145171 Al; WO 2014180778 Al; WO2014199348 AZ; RU 2440962 and RU 2514425.

In the known solutions for the synthesis of butadiene from ethanol, stationary (fixed) catalysts are used to ensure an insufficient yield of butadiene per unit mass of catalyst. In addition, the known catalysts do not provide sufficient operation time before regeneration. Also an important disadvantage of all previously described methods for producing butadiene from ethanol is the use of reactors requiring the supply of heat required for the reaction through the walls of the reactor itself, which leads to a decrease in the efficiency of heat transfer.

DISCLOSURE OF INVENTION

The task and the technical result of the present invention is to develop a one-step process for the synthesis of butadiene from ethanol and mixtures of ethanol with butadiene precursors, ensuring a high yield of butadiene per unit mass of the catalyst and a sufficient period of catalyst operation before regeneration while maintaining the heat transfer efficiency during the reaction.

This technical problem is solved by applying a fractional feed of raw materials along the length of the reactor and carrying out the reaction in a moving bed of catalyst. Through the use of fractional feedstock with different content of precursors of butadiene, for example, acetaldehyde, it is possible to increase the yield of butadiene, and carrying out the reaction in a moving layer allows the synthesis of butadiene in a constant mode without interrupting the synthesis cycle with a regeneration cycle. In the proposed cyclic mode, the heat required for the reaction is partially supplied by supplying a hot freshly regenerated catalyst to the moving stream, which significantly increases heat transfer and reduces material costs for the manufacture of butadiene synthesis reactors.

The proposed process involves the use of both a single partitioned reactor and several reactors for the synthesis of butadiene with a moving catalyst bed, thereby maintaining different conditions in each of the reactors. This allows you to achieve higher, compared with the known solutions, the values of activity, stability and duration of the catalyst.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a block diagram of an installation for the synthesis of butadiene, consisting of several (in this scheme, four) reactors with a moving catalyst bed. Each reactor is equipped with a raw material preheater and an internal heating system. The spent catalyst is fed to the regeneration unit with an oxygen-containing gas. The reaction products are separated on the column into recyclable, light and heavy, from which commercial butadiene is further separated.

IMPLEMENTATION OF THE INVENTION

The synthesis of butadiene is carried out from raw materials containing ethanol, preferably, from 70 to 90 May. % ethanol. The remaining components can be acetaldehyde, ethyl ether, ethyl acetate, butanol-1, or other molecules containing 4 carbon atoms and can be converted to butadiene.

The synthesis of butadiene is carried out at elevated temperatures, preferably from 280 to 350 ° C. The synthesis is carried out at a slight overpressure, preferably from 1.2 to 2 atm.

The synthesis of butadiene is carried out in a single reactor, along the length of which several devices are installed to introduce raw materials, or in several reactors connected in series, to the input of which raw materials of different composition can be supplied. There are no specific requirements for the design of these devices and reactors, it is only important that they ensure the constancy of the linear flow rate of the raw material, the composition of the mixture and its uniform distribution throughout the diameter of the reactor, as well as uniform heating of the entire apparatus.

The catalyst for the synthesis of butadiene may be, for example, described in patent RET 2440962. The catalyst for the synthesis of butadiene must have high activity and selectivity in the synthesis of butadiene from ethanol. Also, the catalyst must have a shape and strength, allowing it to be used in a moving layer.

The synthesis of butadiene is carried out in a moving bed, and the raw materials for the production of butadiene must be fed upward along the length of the entire reactor. Should Note that this method of feeding raw materials into the reactor (or reactors) does not impose restrictions on the reactor and / or its internal structure. It is possible to use several raw material supply devices placed at different levels. In this case, the reaction products, including butadiene, should be removed from the top of the reactor. The deactivated catalyst, after passing through the reactor or all reactors in the case of using more than one reactor, is fed to the regeneration unit, where it is regenerated with a hot oxygen-containing gas. The regenerated catalyst is again sent to the butadiene synthesis reactor. In this case, the heat required to maintain the reaction is supplied, including using a hot, freshly regenerated catalyst. The rest of the heat can be supplied by the coolant pumped through the annular space of the reactors, and / or by heating the raw materials entering each of the reactors, including their different zones. When carrying out the reaction in a moving bed, the catalyst should preferably have a spherical shape and high resistance to abrasion and fracture as the catalyst moves through the reactors.

Below are examples illustrating the implementation of the invention and the achievement of the technical result in comparison with the known methods for producing butadiene.

Example 1

The process of obtaining butadiene from ethanol is carried out on a pilot plant with a moving catalyst bed, the reactor of which is equipped with four raw material input devices evenly spaced along the height of the reactor. The height of the reactor is 2000 mm, the volume of catalyst loaded into the reactor is 8 dm ³ , the total volume of the catalyst circulating in the installation is 20 dm ³ . The catalyst described in patent RU 2440962 and prepared in the form of a ball catalyst with a close to ideal shape of spheres is used. In the process of butadiene synthesis, ethanol containing 1 mass% acetaldehyde is fed to the top of the reactor, 3 mass% acetaldehyde to the next, 5 mass% acetaldehyde and then 10 mass% acetaldehyde to the bottom. The reaction products are cooled, condensed and analyzed by gas chromatography and titration on water according to Fisher. The synthesis process is carried out at a temperature of 320 ° C and a pressure of 1.2 bar (abs.). The total load on the reactor raw materials is 1.57 kg / h, of which 1.35 kg / h of ethanol, 0.07 kg / h of water and 0.15 kg / h of acetaldehyde.

The catalyst is regenerated in a regenerator, where the spent catalyst is fed from the lowest point of the butadiene synthesis reactor. To the regenerator A heated oxygen-containing gas is supplied, usually air diluted with nitrogen or another inert gas, and the regenerative gas is vented from above. By regulating the temperature of the oxygen-containing gas, its flow rate and oxygen concentration, the regeneration temperature is maintained at about 500 ° C, but not more than 550 ° C, which makes it possible to completely restore the activity of the catalyst. This method of regeneration with the supply of oxygen-containing gas to a separate regenerator of the unit with a moving catalyst bed allows to reduce the time spent on regeneration and to avoid local overheating characteristic of the regeneration of the fixed catalyst layer.

After the regeneration is completed, the catalyst is fed to the butadiene synthesis reactor from ethanol via an elevator. The calculation of process indices is performed by averaging the conversion values and process selectivity over three days.

Example 2 (comparative).

The process of obtaining butadiene from ethanol is carried out on a pilot plant with a fixed catalyst bed, the reactor of which is equipped with four input devices evenly spaced along the height of the reactor. The height of the reactor is 2000 mm, the volume of the loaded catalyst is 8 dm ³ . The catalyst described in patent RU 2440962 and prepared in the form of a ball catalyst is used. In the process of butadiene synthesis, 1.35 kg / h of ethanol, 0.07 kg / h of water and 0.15 kg / h of acetaldehyde are fed to the lower point of the reactor. The synthesis process is carried out at a temperature of 320 ° C and a pressure of 1.2 bar (abs.).

After reducing the catalyst activity by 25%, the feed supply is stopped, all the reactor inlets are flushed with nitrogen and regeneration begins. All inputs to the reactor are supplied with heated oxygen-containing gas, usually air, diluted with nitrogen. By regulating the temperature of the oxygen-containing gas, its flow rate and oxygen concentration, the reactor is heated to a temperature of 500 ° C, but not more than 550 ° C, which allows the catalyst activity to be fully restored.

After the completion of catalyst regeneration, which is controlled by the content of carbon oxides in the regenerator gas, the supply of oxygen-containing gas is stopped, the reactor is rinsed with cold nitrogen until the temperature reaches 320 ° C, and the supply of raw materials is started. The calculation of process indicators is made by averaging the conversion values and process selectivity over three days, taking into account the time spent on regeneration. This example reflects the capabilities of the process when using a fixed catalyst bed without a fractional feed of raw materials in the synthesis of butadiene from ethanol with regeneration.

Example 3

The process of obtaining butadiene from ethanol is carried out as described in Example 1, but ethanol containing 3 mass% acetaldehyde is fed to the upper point of the reactor, to the next 5 mass% acetaldehyde, then 10 mass% acetaldehyde and to the bottom 15 mass% acetaldehyde. The total reactor load for raw materials is 1.56 kg / h, of which 1.15 kg / h of ethanol, 0.06 kg / h of water and 0.35 kg / h of acetaldehyde.

Example 4

The process of obtaining butadiene from ethanol is carried out as described in Example 1, but ethanol containing

1 mass% acetaldehyde,

5.5 mass% diethyl ether,

1.5 wt% butanol- 1,

2 mass% ethyl acetate

next -

3 mass% acetaldehyde,

3.5 wt% diethyl ether,

0.5 wt% butanol- 1,

2 mass% ethyl acetate

Further

5 mass% acetaldehyde,

1.5 mass% diethyl ether,

0.5 wt% ethyl acetate

and in the bottom

10 mass% acetaldehyde,

The total reactor load for raw materials is 1.58 kg / hour, of which 1.09 kg / hour of ethanol, 0.08 kg / hour of water, 0.15 kg / hour of acetaldehyde, 0.15 kg / hour of diethyl ether, 0 , 08 kg / h of ethyl acetate and 0.03 kg / h of butanol-1.

Example 5

The process of obtaining butadiene from ethanol is carried out as described in example 1, but the synthesis of butadiene is carried out at a temperature of 280 ° C.

Example 6 The process of obtaining butadiene from ethanol is carried out as described in example 1, but the synthesis of butadiene is carried out at a pressure of 2 bar (abs).

The process indicators for all the examples described are summarized in Table 1. Table 1. Indicators of the process for the synthesis of butadiene in 72 hours.

Thus, the presented examples confirm the possibility of carrying out the method of obtaining butadiene in one stage under the conditions of continuous and fractional supply of raw materials of different composition in a reactor with a moving catalyst bed with the achievement of the stated technical result consisting in providing a high yield of butadiene per unit mass of catalyst and sufficient catalyst life before regeneration while maintaining the efficiency of heat transfer during the reaction.

Although the present invention has been described in detail with examples of variants that appear to be preferred, these embodiments of the invention are given only for the purpose of illustrating the invention. This description is not to be construed as limiting the scope of the invention, since the steps of the method described may be modified without departing from the scope of the appended claims, in order to adapt them to specific conditions or situations. Within the scope of the invention, which is defined by the claims, various variations and modifications are possible, including equivalent solutions.

Claims

CLAIM

1. One-step method of obtaining butadiene, by converting a fractionally supplied raw material containing ethanol and / or at least one precursor of butadiene to butadiene in the gas phase in a catalyst bed with at least one butadiene synthesis reactor having a high attrition resistance and destruction when advancing through the specified reactor.

2. The method according to and. 1, which uses a single partitioned reactor or several reactors with a moving catalyst bed that support the same or different conditions for the reaction of butadiene synthesis.

3. Method according to pi. 1-2, in which raw materials are fed from the bottom up, ensuring the constancy of the linear flow rate of the raw materials, the specified composition of the mixture and its uniform distribution throughout the diameter of the reactor, as well as uniform heating of the entire reactor volume.

4. The method according to p. 3, in which the heat required to maintain the reaction is supplied, including by feeding a freshly regenerated hot catalyst into the moving layer.

5. The method according to and. 1, which use raw materials containing ethanol, preferably from 70 to 90 May. %

6. The method according to and. 1, in which acetaldehyde, ethyl ether, ethyl acetate, butanol-1 or other molecules containing 4 carbon atoms and capable of being transformed into butadiene are used as the precursor of butadiene.

7. The method according to and. 1, in which the conversion is carried out at elevated temperatures, preferably from 280 to 350 ° C.

8. The method according to and. 1, in which the conversion is carried out with a slight excess charge, preferably from 1.2 to 2 atm.