Esterification unit for producing crude methyl methacrylate, esterification process using said unit and plant comprising said unit

Patent metadata

Field	Value
Publication number	US-10131614-B2
Application number	US-201415028745-A
Country	US
Kind code	B2
Filing date	Oct 17, 2014
Priority date	Oct 18, 2013
Publication date	Nov 20, 2018
Grant date	Nov 20, 2018

Abstract

The invention relates to an esterification unit ( 150 ) and esterification process for producing crude methyl methacrylate (MMA) from methacrylamide (MAM), which enable particularly to improve the yield, meaning that the organics spent acids are low; and at the same time, providing crude MMA with rather good quality, meaning that MMA concentration in crude MMA is rather high and preferably from 50 wt % to 80 wt %. According to the invention, the esterification unit comprises esterification reactors ( 1, . . . , 5 (or 6 ) set up in a serial way so that there is a counter current flow between gaseous phase and liquid phase, the liquid phase flowing from first reactor ( 1 ) of the series to last reactor ( 5 (or 6 )), and the gaseous phase flowing from reactor to first reactor ( 1 ).

First claim

The invention claimed is:

1. An esterification unit for producing crude methyl methacrylate (MMA) from methacrylamide (MAM), and at least methanol and water, said esterification unit comprising reactors ( 1 , . . .n, n+1, . . . , . . . N), wherein “n” represents the number of each reactor in the series of reactors ( 1 , 2 , 3 , 4 , 5 etc.), and “N” represents the last reactor in the series, each reactor having an upper part and a lower part, wherein the reactors are set up in a serial way so that there is a counter current flow between a gaseous phase and a liquid phase, the liquid phase flowing from a first reactor ( 1 ) of the series to a last reactor (N), and the gaseous phase flowing from the last reactor (N) to the first reactor ( 1 ),
the first reactor of the series comprising:
methacrylamide, methanol and water lateral inlets,

the last reactor (N) comprising a lateral steam inlet located at the lower part,
and each reactor ( 1 , . . . n, n+1, . . . N) also comprising:
at least a gaseous phase outlet, at the top of the upper part,
at least a gaseous phase inlet at the lower part, the reactors being connected in such a manner that the gaseous phase outlet of reactor (n+1) is linked to the gaseous phase inlet of reactor (n), at least a liquid phase outlet located at the bottom of the lower part,
at least a lateral liquid phase inlet located at the lower part, the reactors being connected in such a manner that the liquid phase outlet of reactor (n) is linked to the lateral liquid phase inlet of reactor (n+1),
at least another lateral liquid phase inlet located at the lower part, the liquid phase outlet of reactor (n) being linked to said another lateral liquid phase inlet of said reactor (n);

said esterification unit further comprising an additional reactor (N+1) comprising:
at least a first and a second lateral liquid phase inlet located at the lower part,
at least a gaseous phase outlet at the top of the upper part,
at least a liquid phase outlet located at the bottom of the lower part, and
at least a lateral steam inlet located at the lower part,
said additional reactor (N+1) being connected in a parallel way to the last reactor (N) of the series in such a manner that said additional reactor (N+1) is alternatively linked to a penultimate reactor (N−1), the gaseous phase outlet of the additional reactor (N+1) being linked to a lateral gaseous phase inlet of said penultimate reactor (N−1), a liquid phase outlet of said penultimate reactor (N−1) being linked to the first lateral liquid phase inlet of the additional reactor (N+1), and the liquid phase outlet of said additional reactor (N+1) being linked to the second lateral liquid phase inlet of said additional reactor (N+1).

2. The esterification unit according to claim 1 , wherein a second and/or third reactor of the series comprises a third liquid phase inlet at the lower part for feeding methanol.

3. The esterification unit according to claim 1 , wherein each reactor comprises a gaseous phase distributor ( 90 ) located inside the lower part of the reactor.

4. The esterification unit according to claim 3 , wherein the gaseous phase distributor ( 90 ) comprises a pipe going horizontally from a lateral wall of the reactor to the middle of the reactor, said horizontal pipe having at its end at least three nozzles.

5. The esterification unit according to claim 3 , wherein a material of the gaseous phase distributors ( 90 ) is selected from an iron/nickel alloy and zirconium.

6. The esterification unit according to claim 1 , wherein said unit comprises a separation means to separate methacrylic acid from crude methyl methacrylate (MMA), said separation means being connected to the gaseous phase outlet of the first reactor.

7. The esterification unit according to claim 6 , wherein said separation means comprises:
a first partial condenser for liquefying gaseous phase, having at least an inlet linked to the gaseous phase outlet of the first reactor with a temperature between 98° C. to 102° C., and at least an outlet providing liquid phase at a temperature between 80° C. and 84° C.,
a drum device able to separate the obtained liquid phase from gaseous phase, separating acids from crude MMA, said drum device having an inlet connected to the outlet of the first partial condenser; and an acids outlet linked to the lateral liquid inlet of the first reactor and, having a gaseous phase crude MMA outlet,
a total condenser for liquefying the gaseous phase crude MMA, said total condenser comprising a gaseous phase inlet linked to the gaseous phase crude MMA outlet of the drum device, and an outlet for a liquid phase crude MMA,
a recovery drum linked to the outlet of the total condenser for recovering the liquid phase crude MMA, comprising a crude MMA outlet and a light components outlet,
a trap condenser, linked to the light components outlet of the recovery drum, for recovering light components, including methanol and comprising an outlet vent,
and a cooling device for cooling crude MMA, comprising an inlet linked to the crude MMA outlet of said recovery drum and comprising a crude MMA outlet with a concentration of MMA being of 50% to 80%.

8. The esterification unit according to claim 7 , wherein the first partial condenser and the total condenser are cooled by a controlled flow of chilled water (CW).

9. The esterification unit according to claim 7 , wherein the total condenser is configured to condense at least 99% of the crude MMA gaseous phase.

10. The esterification unit according to claim 1 , wherein each reactor further comprises an additional liquid phase outlet, making two liquid phase outlets, a first outlet and a second outlet located at the bottom of the lower part, a first centrifugal pump being connected to said first outlet and a second centrifugal pump being connected to said second outlet, each centrifugal pump having an outlet, said outlet being linked to the lateral liquid phase inlets located at the lower part of two successive reactors.

11. The esterification unit according to claim 10 , wherein, said first outlet and said second outlet are each respectively connected to said first centrifugal pump and said second centrifugal pump via a basket filter (F).

12. The esterification unit according to claim 11 , wherein a material of the basket filters (F) is selected form an iron/nickel alloy and zirconium.

13. The esterification unit according to claim 1 , wherein each reactor comprises at least a temperature control device (TA), a pressure control device (PA) and level control device (LC), and said level control device regulates the flow of liquid though the liquid phase outlet to maintain a constant liquid level inside each reactor.

14. The esterification unit according to claim 13 , wherein the lateral liquid phase flow is fed to reactors (n) and (n+1), via control valve devices activated by the level control device (LC).

15. The esterification unit according to claim 1 , wherein said unit comprises a steam control flow device (V 20 , FC) able to regulate the steam flow according a predetermined flow rate (FC).

16. The esterification unit according to claim 1 , wherein, said unit comprises 3 to 8 reactors ( 1 , . . . n, n+1, . . . N), being set up in serial way and the additional reactor (N+1) being connected in a parallel way to the last reactor (N).

17. The esterification unit according to claim 16 , wherein said unit has 5 or 6 total reactors, wherein a material of the last reactors (N, N+1) is selected from zirconium, titanium, lead, nickel/molybdenum alloys, iron/nickel alloys, and tantalum

Assignees

• Arkema France

Inventors

• Bernardin Yves
• Billon Romain
• Marcarian Xavier
• Vallet Florent

Classifications

• C07C69/54

  Acrylic acid esters; Methacrylic acid esters · CPC title

• B01J19/1862

  placed in series · CPC title

• B01J10/00

  Chemical processes in general for reacting liquid with gaseous media other than in the presence of solid particles, or apparatus specially adapted therefor (B01J19/08 takes precedence; separation, e.g. distillation, also combined with chemical reactions B01D, {e.g. B01D3/009}) · CPC title

• B01J19/2465

  externally, i.e. the mixture leaving the vessel and subsequently re-entering it · CPC title

• B01J4/002

  Nozzle-type elements (nozzle-type reactors B01J19/26) · CPC title