METHOD FOR MANUFACTURE OF ETHYLENEAMINES

Abstract

The present invention relates to a method for the manufacture of ethyleneamine from a mixture comprising water (H.sub.2O), ethylenediamine (EDA) and N-methylethylendiamine (NMEDA), comprising the steps of: (i) providing a feed stream comprising EDA, NMEDA and water; (ii) separating the feed stream provided in step (i) in the one or more distillation columns into a. a fraction A comprising water and NMED A wherein the weight ratio of water to NMEDA in fraction A is more than 100:1; b. a fraction B comprising water, NMEDA and EDA wherein the weight ratio of water to NMEDA is in the range of 1:100 to 100:1; and c. a fraction C comprising water and EDA wherein the weight ratio of EDA to water is more than 5:1.

Claims

1-22. (Canceled)

23. A method for the manufacture of ethyleneamine from a mixture comprising water (H.sub.2O), ethylenediamine (EDA) and N-methylethylendiamine (NMEDA), comprising the steps of: (i) providing a feed stream comprising EDA, NMEDA and water; (ii) separating the feed stream provided in step (i) in the one or more distillation columns into a. a fraction A comprising water and NMEDA wherein the weight ratio of water to NMEDA in fraction A is more than 100:1; b. a fraction B comprising water, NMEDA and EDA wherein the weight ratio of water to NMEDA is in the range of 1:100 to 100:1; and c. a fraction C comprising water and EDA wherein the water content in fraction C is in the range of 0.1 to 10 percent by weight; and (iii) separating fraction C into: a fraction C-1 comprising EDA, NMEDA and water, wherein the weight ratio of EDA to water is in the range of 1:5 to 5:1 and the weight ratio of NMEDA to EDA is in the range of 100:1 to 1:1, and a fraction C-2 comprising EDA and components with a boiling point higher than EDA and in which the NMEDA content is 0.01 percent by weight or less.

24. The method according to claim 23, wherein the feed comprising EDA, NMEDA and water comprises 1 to 30 percent by weight of EDA, 1 to 30 percent by weight of water and 0.001 to 1 percent by weight of NMEDA.

25. The method according to claim 23, wherein the feed provided in step (i) additionally comprises components having a boiling point higher than EDA.

26. The method according to claim 25, wherein one of the components having a boiling point higher than EDA is monoethanolamine (MEOA).

27. The method according to claim 23, wherein providing a feed in step (i) comprises the steps of: (i-a) carrying out an EDA preparation process to obtain an output comprising EDA, NMEDA and water; (i-b) removing ammonia and/or hydrogen from the output produced in step (i-a); and (i-c) optionally adding an additional adjuvant.

28. The method according to claim 23, wherein the EDA preparation process in step (i-a) is a process in which monoethylelene glycol (MEG) is converted with ammonia in the presence of an amination catalyst and hydrogen.

29. The method according to claim 23, wherein the separation step (ii) is carried out under conditions in which the azeotrope between EDA and water is broken, impaired or otherwise modified so that fraction A can be separated from NMEDA as a low boiling fraction.

30. The method according to claim 29, wherein the separation (ii) is carried out at a pressure lower than those required to break the EDA-water azeotrope.

31. The method according to claim 30, wherein the feed provided in step (i) comprises an additional adjuvant.

32. The method according to claim 31, wherein the additional adjuvant is a compound other than an ethanolamine or an ethyleneamine.

33. The method according to claim 32, wherein the additional adjuvant is a hydroxyl group comprising compound.

34. The method according to claim 33, wherein the additional adjuvant) is selected from a group comprising: (i) aliphatic monools, (ii) aliphatic diols; (iii) aliphatic triols; or (iv) aliphatic tetrols.

35. The method according to claim 34, wherein the additional adjuvant provided in step (i) is an aliphatic diol selected from the group of ethylene glycol, 1,2 propylene glycol and 1,2 butanediol.

36. The method according to claim 33, wherein amount of additional adjuvant provided in step (i) is adjusted so that the molar ratio of hydroxyl groups in the feed to EDA molecules present in the feed is 1:1 or more.

37. The method according to claim 35, wherein the additional adjuvant is MEG.

38. The method according to claim 37, wherein the molar ratio of MEG to EDA is 1:1 or more.

39. The method according to claim 23 wherein the separation in step (ii) is carried out in a one distillation column in which fraction A is drawn-off at the top, fraction B is drawn-off as a side fraction and fraction C is drawn-off at the bottom of the distillation column.

40. The method according to claim 39, wherein the bottom temperature of the column is 160 C. or less.

41. The method according to claim 23, wherein the fraction C-2 is further separated into: a fraction D-1 comprising EDA; a fraction D-2 comprising PIP; and a fraction D-3, comprising components having a boiling point higher than PIP, in particularly MEOA, MEG, DETA, AEE, DEOA and TETA.

42. The method according to claim 41, wherein the separation of fraction C-2 is conducted in a single dividing wall column.

Description

EXAMPLES

[0382] The examples are based on calculations performed using a process simulation model.

[0383] The simulations have been performed using CHEMASIM. For the calculation of thermodynamic properties of pure components, like the vapor pressure, DIPPR correlations have been used. For the description of phase equilibria, the ideal gas law is used to describe the vapor phase and the NRTL excess Gibbs energy model is used for the description of the liquid phase. The parameters of the DIPPR correlations and the parameters of the NRTL model were adjusted to experimental data. For the components, for which no experimental data are available, the UNIFAC group contribution method was used for the description of the liquid phase in phase equilibria calculations. The distillation columns have been modelled and calculated using the equilibrium stage model. The employed simulation and thermodynamic property models have been adjusted to reproduce experimental and plant data with very good accuracy.

Example 1

[0384] A feed was prepared in a combined MEG/MEOA process.

[0385] After the removal of and hydrogen and ammonia the feed comprised: [0386] water: 15.80 percent by weight [0387] NMEDA: 0.04 percent by weight [0388] EDA: 18.81 percent by weight [0389] PIP: 1.81 percent by weight [0390] MEOA: 16.67 percent by weight [0391] MEG: 42.07 percent by weight [0392] DETA: 1.96 percent by weight [0393] AEPIP: 0.21 percent by weight [0394] AEEA: 1.65 percent by weight

[0395] The molar ratio of MEG to EDA in the feed stream is 2.17 to 1. The molar ratio of hydroxyl groups to EDA was approximate 6:1.

[0396] 1725.72 kg/h of the feed stream were fed to the NMEDA Removal Column where it was separated into a fraction A, a fraction B and a fraction C.

[0397] The NMEDA-Removal Column was equipped with a reboiler and had 28 stages

[0398] The feed was introduced above stage 12 (counted from the bottom).

[0399] The bottom temperature was 159 C.

[0400] 644.26 kg/g of fraction A comprising water and 100 weight ppm NMEDA (weight ratio of water to NMEDA: approx. 10000:1) was withdrawn from the top of the column and fed to a condenser operated at 100 C.

[0401] 372.12 kg/h of the condensed stream were refluxed back to the top of the NMEDA Removal Column, and a stream of 272.13 kg/h was removed.

[0402] 1.58 kg/h of a fraction B comprising: [0403] 40.1 percent by weight of water [0404] 41.8 percent by weight of NMEDA [0405] 18.1 percent by weight of EDA
was withdrawn as a side draw between stages 17 and 18.

[0406] Accordingly, the weight ratio of water to NMEDA was approximately 0.96:1.

[0407] 1847.93 kg/h of fraction C comprising. [0408] water: 1.05 percent by weight [0409] NMEDA: 0.01 percent by weight [0410] EDA: 32.40 percent by weight [0411] PIP: 2.30 percent by weight [0412] MEOA: 18.55 percent by weight [0413] MEG: 41.11 percent by weight [0414] DETA: 1.88 percent by weight [0415] AEPIP: 0.20 percent by weight [0416] AEEA: 1.57 percent by weight
was with withdrawn from the bottoms of the NMEDA Removal Column and fed to an additional Residual Water Removal Column. The weight ratio of EDA to water in fraction C was approximately 30.9 to 1.

[0417] Fraction C was further separated into a fraction C-1 and into a fraction C-2 in a Residual Water Removal Column equipped with a reboiler and having 36 stages.

[0418] Fraction C was introduced above stage 36.

[0419] The Residual Water Removal Column was operated at a bottom temperature of 181 C. and a top pressure of 1.3 bar.

[0420] 395.93 kg7h or fraction C-1 comprising: [0421] water: 4.86 percent by weight [0422] NMEDA: 0.028 percent by weight [0423] EDA: 69.36 percent by weight [0424] PIP: 2.88 percent by weight [0425] MEOA: 13.91 percent by weight [0426] MEG: 8.55 percent by weight [0427] DETA: 0.24 percent by weight [0428] AEPIP: 0.03 percent by weight [0429] AEEA: 0.12 percent by weight
was withdrawn from the top of the Residual Water Removal Column. This stream was directly fed in vaporous form without condensation to the bottom of the NMEDA Removal Column.

[0430] 1452.00 kg/h of a fraction C-2 comprising: [0431] water: 0.01 percent by weight [0432] NMEDA: 0.00009 percent by weight [0433] EDA: 22.32 percent by weight [0434] PIP: 2.15 percent by weight [0435] MEOA: 19.80 percent by weight [0436] MEG: 49.99 percent by weight [0437] DETA: 2.33 percent by weight [0438] AEPIP: 0.25 percent by weight [0439] AEEA: 1.97 percent by weight
was withdrawn from the bottom of the Residual Water Removal Column and was purified in a dividing wall column. A pure EDA fraction comprising 500 ppm by weight of water and 2 ppm by weight of NMEDA was obtained.

Example 2: Provision of a Feed Comprising EDA, NMEDA and Water

[0440] A feed was prepared in a combined MEG/MEOA process.

[0441] After the removal of and hydrogen and ammonia the feed comprised: [0442] water: 9.03 percent by weight [0443] NMEDA: 0.07 percent by weight [0444] EDA: 7.07 percent by weight [0445] PIP: 0.72 percent by weight [0446] MEOA: 12.96 percent by weight [0447] MEG: 68.82 percent by weight [0448] DETA: 0.72 percent by weight [0449] AEEA: 0.07 percent by weight [0450] TETA: 0.51 percent by weight

[0451] The molar ratio of MEG to EDA in the feed stream is 9.43 to 1. The molar ratio of hydroxyl groups to EDA was approximate 18.9:1.

[0452] 2459.7 kg/h of the feed stream were fed to an NMEDA Removal Column where the feed was separated into a fraction A, a fraction B, and a fraction C.

[0453] The NMEDA-Removal Column was equipped with a reboiler and had 25 stages

[0454] The feed was introduced above stage 12 (counted from the bottom).

[0455] The bottom temperature was 180 C.

[0456] 354.15 kg/g of fraction A comprising water and 100 weight ppm NMEDA (weight ratio of water to NMEDA: approx. 10000:1) was withdrawn from the top of the column and fed to a condenser operated at 100 C.

[0457] 134.79 kg/h of the condensed stream were refluxed back to the top of the NMEDA Removal Column, and a stream of 219.36 kg/h was removed.

[0458] A fraction A comprising water and 100 weight ppm NMEDA was removed from the top of the column. Accordingly, the weight ratio of water to NMEDA was approx. 10000:1.

[0459] 4.35 kg/h of a fraction B comprising: [0460] 5.43 percent by weight of water [0461] 36.9 percent by weight of NMEDA [0462] 7.62 percent by weight of EDA was withdrawn as a side draw between stages 16 and 17.

[0463] Accordingly, the weight ratio of water to NMEDA was approximately 6.17:1.

[0464] 2235.92 kg/h of fraction C comprising. [0465] water: 1.05 percent by weight [0466] NMEDA: 0.002 percent by weight [0467] EDA: 7.76 percent by weight [0468] PIP: 0.79 percent by weight [0469] MEOA: 14.26 percent by weight [0470] MEG: 75.71 percent by weight [0471] DETA: 0.79 percent by weight [0472] AEEA: 0.04 percent by weight [0473] TETA: 0.56 percent by weight
was with withdrawn from the bottoms of the NMEDA Removal Column. The weight ratio of EDA to water in fraction C was approximately 236.5 to 1.

[0474] Fraction C was purified in a distillation column with 60 stages. Fraction C was fed to the column between stage 36 and 37 (counted from the bottom). A top fraction comprising 99.80 percent by weight of EDA, 0.12 percent by weight of water. 0.03 percent by weight of NMEDA and 0.05 percent by weight of PIP was obtained.

[0475] Example 1 shows that by separating the feed stream from an EDA preparation process into thee fractions according to the present invention from the NMEDA Removal Column, a commercial grade of EDA can be obtained in only one additional distillation step. The losses of EDA are comparatively small and lie in the order of magnitude as the NMEDA present in the feed.

[0476] In Example 2, the water concentration in the bottom of the NMEDA Removal Column is comparatively higher. This allows to obtain an EDA having an ultra-low NMEDA content.