SU1154264A1 - Method of obtaining maleic anhydride - Google Patents

Abstract

A method for producing malein anhydride by oxidation of i-butane with oxygen by contacting the butane-air mixture with a catalyst containing vanadium oxide and phosphorus, promoted with cobalt compounds, at 450500 0, characterized in that with a chain of yield of the target product, the process selectivity, Also, removal of the target product from a unit volume of catalyst, contacting the butano-air mixture is carried out in an upward flowing catalyst flow at a contact time O, -15-0.25 s, grain size, catalyzed ora 0,20, 63 mm and its concentration 115147 kg / m. SL

Description

This invention relates to a method for producing maleic anhydride, which is used in the manufacture of polyester resins.

A known method of producing mapeinic anhydride by the oxidation of i -butane in a stationary layer of a promiruated vanadium phosphoric oxide catalyst at 350-550 ° C, contact time 0.5-4 s lj.

There is also known a method according to which maleic anhydride is obtained by oxidation of the butane-isobutane fraction in a stationary catalyst bed containing vanadium and phosphorus oxides, at 250-600 0, contact time of 0.1-50 s followed by recycling of unreacted hydrocarbon 2J.

The disadvantages of these methods for producing maleic anhydride are low selectivity for the target product (about 60%) and long contact time of the catalyst with the raw material.

The most technically and achievable result to the proposed is a method of producing maleic anhydride by oxidation of N-butane with air in the presence of an oxide vanadium phosphorus catalyst promoted with cobalt or nickel compounds. The process is carried out in a fixed catalyst bed with a particle size of 11.6 mm at 350-500 ° C and a contact time of 0.5-4.0 s. The yield of maleic anhydride is 55% with a selectivity of 61%, and the removal of the target product is 60 g / l of catalyst per hour of a three-hour charge.

The disadvantages of this method are low selectivity for maleic anhydride, long contact time, low removal of the target product from 1 liter of catalyst per hour.

The purpose of the invention is to increase the yield of the target product, the selectivity of the process, as well as the removal of the target product per unit volume of catalyst.

This goal is achieved in that according to the method of producing maleic anhydride, which involves oxidation of n-butane with oxygen by contacting the butane-air mixture with the catalyst.

4264a

containing vanadium and phosphorus, promoted with cobalt compounds, at 450-500 ° C, the butane-air mixture is contacted in an upstream direct flow of the catalyst at a contact time of 0.15-0.25 s, the grain size of the catalyst 0.2-0.63 mm and its concentration 115-147 kg / m3.

Exit maleic anhydride

65-80%; selectivity 65-80%; removal of the desired product is 300-450 g / l cat. hours.

The drawing shows a schematic diagram of the process for producing maleic anhydride.

The method is carried out as follows.

The required amount of a catalyst containing oxides of vanadium and phosphorus promoted with cobalt compounds prepared by the method of Gz is loaded into the reaction device. The composition of the catalyst V: p: Co 1: 1.16: 0.19 (at.) Grain size 0.2-0.63 mm. Then into the reactor 1 through the regulator valve, the mixer serves preheated to butano-air

the mixture, which captures continuously the catalyst entering the valve-mixer from the pressure stand 2, transports it, with a concentration of 110150 kg / m, to the reaction zone, the reactor is heated to 400500V,. The contact time is 0.15-0.25 s. In the reaction zone, the oxidation of β-butane according to the scheme

 ,

 OO "- CO

The reaction products at the outlet of the reaction zone 1 enter the separator 3, where the catalyst is separated from the contact gas, which flows along the pressure stand 2 to the mixer valve 4. Thus, the catalyst is continuously circulated in the reaction system.

Contact gas containing maleic anhydride, CO, - COj, water vapor and. unreacted n-butane, after the reactor, enters two water-irrigated absorbers 5 to absorb maleic anhydride. After removal of mapeinic anhydride, the gas mixture using a three-way valve 6 passes through alternately working adsorbers 7, filled with activated carbon, to remove unreacted and -butane. To carry out the recycling of the n-butane through the adsorber 7, air is passed through the aid of a rotameter 8, a three-way valve 5 or 1 O and 11. After the adsorber 7, the gas mixture containing the desorbed AND -butane, after the three-way valve 12, is added to the required concentration with fresh N-tan and re-directed through the furnace J3 by preheating the reactor. Deadening the process of producing maleic anhydride in the direct flow of the gas-catalytic mixture makes it possible to eliminate diffusion complications, improve the flow of particles with the butane-air mixture, intensify the heat and mass transfer of the phases, thereby fully utilizing the active surface of the catalyst, increasing the code and removing the maleic anhydride. 1l of catalyst n h. P P and m 6; p 1. Process mode f contact time 0.25 s con: zeitration of catalyst 146.5 kg / m. Served in the reaction wt.% Vol.% H-Butane 2.38 1.20 Air 97.62 98.80 Obtained as a result of the reaction: Maleic anhydride Carbon monoxide CO 0.29 0.30 Carbon dioxide CO 2 N-Butane Air 95.91 96, 76 Conversion N-butane is 32.7%. The yield of maleic anhydride in a single pass 23.0 mol.%. The selectivity of the process for maleic anhydride is 70.4%. Taking into account the solution of un-reacted N-butane in one pass, the yield of maleic anhydride reaches 70.4 mol%. Removal of maleic anhydride 306 g / l of catalyst per hour. Example 2. Process mode: 480C; contact time 0.23 cf end of catalyst traction 134 kg / m. 4 Served in the reaction: vol.% Weight. 2.42 H-Vutane 1.22 Air 97.58 98.78 Obtained as a result.% Vol.% Of the reaction maleic anhydride Carbon monoxide CO Carbon dioxide COj Water H-Butane Air Conversion and butane 36.5%. The yield of maleic anhydride in a single pass of 25.5 mol.%. The selectivity of the process for maleic anhydrite is 69.8%. With recirculation of the un-reacted c-butane in one pass, the yield of maleic anhydride reaches 69.8%. Removal of maleic anhydride 405 g / l of catalyst per hour. Example 3 Process mode: contact time 0.225 ci, catalyst concentration 134 kg / m. The reaction is carried out: wt.% Vol. N-Butane 2.42 1.22 Air 97.58 98.78 Obtained as a result of the reaction: Maleic anhydride Carbon monoxide CO Carbon dioxide C02 N-Butane Air Conversion n-butane 38.0 % The output of maleic anhydri) and in one pass of 26.1 mol.%. The selectivity of the process for maleic anhydride is 68.8%. Taking into account the recycling of un-reacted N-butane in one pass, the yield of maleic anhydride reaches 68.8 mol%. Removal of maleic anhydride 415 g / l of catalyst per hour. , Example 4. Process mode:, contact time 0.15 s, catalyst concentration 117 kg / m. The reaction is carried out: wt% by volume ih-Butane2.511.27 Air97.49 98.73 The reaction is obtained:

wt.% OBL

Maleic

0.18

0.61 anhydride carbon monoxide CO + carbon dioxide

0.20

0,21 WITH,

g 0,60 0,99 Water 1,04

N-butane 2.05 97.58 96.54

Air

Conversion n-butane 18.4%. The output of the maleic anhydride in a single pass of 14.4 mol.%. The selectivity of the process for maleic anhydride is 78.4%. Taking into account the recycling of un-reacted K butane in one pass, the yield of the maleic anhydride reaches 78.4 mol%. Removal of the maleic anhydride 396 g / l of catalyst per hour.

Example 5. Process mode: 500 ° C, contact time 0.222 s, catalyst concentration 134 kg / m. Supplied:

wt.% vol.%

N-butane 2.37 1.20 Air 97.63 98.80 receive as a result of the reaction:

Maleic anhydride carbon monoxide CO

Carbon dioxide CO Water I-Vutan Air

Conversion of I-butane 43.4%. The output of the maleic anhydride in a single pass 28.3 mol.%. The selectivity of the process for maleic anhydride is 65.4%. The yield of the maleic anhydride, taking into account the recirculation of unreacted N-butane, is 65.4 mol%. Removal of the maleic anhydride 445 .g / l of catalyst per hour. I

Claims (1)

METHOD FOR PRODUCING MALEIC ANHYDRIDE by oxidation of N-butane with atmospheric oxygen by contacting the butane-air mixture with a catalyst containing vanadium and phosphorus oxide promoted with cobalt compounds at 450500 ° C, characterized in that, in order to increase the yield of the target product, the selectivity of the process, and also the removal of the target product from a unit volume of the catalyst, the contacting of the butane-air mixture is carried out in an upstream direct-flow catalyst stream at a contact time of 0.15-0.25 s, the catalyst grain size is 0.2- ~ 0.63 mm and its concentration of 115-5 147 kg / m ³ . 1154264>