RECYCLING PROCESS FOR ADSORBER REGENERATION

Abstract

The invention relates to a process for the regeneration of an adsorber. For the regeneration a liquid stream (S2) comprising at least one alkane is converted from liquid phase into gaseous phase. Then the adsorber is regenerated and heated by contact with gaseous stream (S2) up to 230 to 270° C. Subsequently, the adsorber is cooled first by contact with gaseous stream (S2) to a temperature of 90 to 150° C. followed by cooling with liquid stream (S2) to a temperature below 80° C. The outflow of the adsorber (S2*) during the cooling with gaseous stream (S2) and optionally the outflow of the adsorber (S2*) during cooling with liquid stream (S2) is recycled in at least one of these steps.

Claims

1-15. (Canceled)

16: Process for the regeneration of an adsorber comprising the steps a) to e): a) converting a stream (S2) comprising at least one alkane from liquid phase into gaseous phase, b) regenerating the adsorber by contact with gaseous stream (S2) in a range of 230 to 270° C., c) cooling the adsorber by contact with gaseous stream (S2) obtained in step a) to a temperature in a range of 90 to 150° C., d) optionally cooling the adsorber to a temperature below 80° C. by contact with liquid stream (S2) without prior conversion into gaseous phase, e) recycling of the outflow (S2*) of the adsorber as obtained in step c) or optionally in step d), wherein the outflow (S2*) is at least partially recycled to at least one of the steps a) to d).

17: The process according to claim 16, comprising a further step f): f) hydrogenation of a stream (S1) comprising at least one alkane and at least one olefin, carried out prior to step a), to obtain a liquid stream (S2) comprising at least one alkane and a reduced amount of at least one olefin compared to the amount of stream (S1).

18: The process according to claim 16, wherein i) in step f), the stream (S1) comprises butane and butene, or ii) the stream (S2) comprises not more than 1000 wt-ppm olefin, or iii) the stream (S2) comprises at least 99 wt-% of at least one alkane, or iv) in step e), the outflow (S2*) comprises >99.5 wt-% of the stream (S2), or v) at least 10% of the outflow (S2*) is recycled to at least one of the steps a) to d).

19: The process according to claim 18, wherein i) in step f), the stream (S1) comprises at least 96 wt-% butane and not more than 4 wt-% butane, or ii) the stream (S2) comprises at least 99 wt-% of butane.

20: The process according to claim 17, wherein the stream (S1) originates from an organic composition which has been purified earlier by the same adsorber or by a similar further adsorber during the operation mode of the respective adsorber.

21: The process according to claim 20, wherein an oligomerization of olefins, or a distillation step to separate butane from butene is carried out prior to step f) and after the purification of the organic composition employing at least one adsorber in its operation mode.

22: The process according to claim 21, wherein the oligomerization is a dimerization of butene to octane.

23: The process according to claim 16, wherein i) prior to carrying out step b) a draining step g) is carried out in order to at least partially remove an organic composition which was passed through the adsorber during its operation mode, optionally the organic composition obtained in the draining step g) is collected in a device, in order to pass the collected condensate through an adsorber during its operation mode, or ii) condensate obtained in step b), comprising the stream (S2) and the residue of the organic composition which was not removed from the adsorber when carrying out draining step g), is collected in a device, in order to pass the collected condensate through an adsorber during its operation mode.

24: The process according to claim 16, wherein the outflow (S2*) obtained from the adsorber in step e) is i) condensed by at least one condenser or cooler to obtain a liquid outflow (S2*) and at least partially recycled for being reused as liquid stream (S2) in at least one of the steps a) or d), or ii) compressed, when still in gaseous phase, by at least one compressor to obtain a gaseous outflow (S2*) and at least partially recycled for being reused as gaseous stream (S2) in at least one of the steps b) or c).

25: The process according to claim 24, wherein option ii) is carried out without prior evaporation in an evaporator or routing through at least one flash vessel.

26: The process according to claim 24, wherein at least one compressor is a jet compressor or i) the stream (S2) fed into the jet compressor has a pressure of 10 to 40 bar, or ii) the pressure of stream (S2) fed into the jet compressor is 5 to 30 bar higher, than the pressure of the outflow of the jet compressor, or iii) the pressure of stream (S2) fed upstream into a flash vessel and the pressure of the outflow of the flash vessel, comprising stream (S2), is 10 to 40 bar.

27: The process according to claim 16, wherein step b) comprises at least one of the following component steps b1) to b3): b1) heating the adsorber by contact with the gaseous stream (S2), wherein the gaseous stream (S2) is condensed within the adsorber, b2) heating the adsorber by contact with the gaseous stream (S2) up to a temperature in the range of 230 to 270° C. without any condensation of the gaseous stream (S2) within the adsorber, b3) regeneration of the absorber at a temperature in the range of 230 to 270° C. by contact with the gaseous stream (S2) or wherein cooling in step d) lowers the temperature of the adsorber to 40 to 60° C.

28: The process according to claim 27, wherein step g) is carried out prior to step b) and step e) is carried out at the same time as step c), optionally as step d) and step b) comprises the component steps b1), followed by b2), followed by b3), followed by step c), followed by step d).

29: The process according to claim 16, wherein the absorbent in the adsorber is based on aluminium oxide or the absorber can be employed for the adsorption of compounds containing oxygen or sulphur out of organic compositions.

30: The process according to claim 29, wherein the absorber can be employed for the adsorption of ethers, alcohols, thiols, thioethers, sulfoxides, ketones, aldehydes, or mixtures thereof.

31: The process according to claim 16, wherein in step a) the conversion is carried out by heating the liquid stream (S2).

32: The process according to claim 16, wherein the heating is carried out by employing at least one evaporator or at least one super-heater or at least one flash vessel.

33: The process according to claim 16, wherein i) the heating rate of the adsorber does not exceed 60° C./h, or ii) the temperature of the gaseous stream (S2) is not more than 100° C., higher than the temperature of the adsorber, especially during the heating steps b1) or b2), or iii) the temperature of the gaseous or optionally liquid stream (S2) is not more than 100° C., lower than the temperature of the adsorber.

34: The process according to claim 16, wherein i) subsequent to step b), the outflow obtained from the absorber, comprising gaseous stream (S2) and the impurities removed from the adsorber is condensed at least partially, or ii) after finishing the regeneration of the adsorber according to step d), the adsorber is switched into its operation mode by feeding it with an organic composition to be purified.

35: The process according to claim 16, wherein the adsorber to be regenerated in step b) and to be cooled in step c) or d) is part of an assembly which contains at least one further adsorber.

36: The process according to claim 35, wherein the at least one further adsorber is in its operation mode during the regeneration of the first adsorber, or each adsorber within this assembly is identical in respect of the adsorber material or its modes of operation.

37: The process according to claim 35, wherein the recycled outflow according to step e) of one adsorber can be reused in at least one of the steps a) to e) for the same adsorber or the at least one further adsorber.

Description

FIGURES

[0133] The FIGS. 1 to 4 illustrate certain aspects of the invention. For the sake of clarity not all applicable components and embodiments are drawn in one and/or all figures. Embodiments shown in different figures may be combined with each other and do not exclude the incorporation of further components within the limits of the disclosure of the specification.

[0134] FIG. 1 illustrates the most basic assembly of the present invention. The stream (S2) is routed through the evaporation/heating unit (EHU) in order to be converted from the liquid into gaseous phase. Then the adsorber (A) is regenerated by contact with gaseous stream (S2) coming from the evaporation/heating unit (EHU) fed into the adsorber in opposite direction to the direction of flow of the stream (S3). The stream (S3) comprises organic composition and compounds containing heteroatoms. The stream (S5) comprises organic composition and no compounds containing heteroatoms or a lower amount of compounds containing heteroatoms than stream (S3). Stream (S5) is leaving adsorber (A) on the opposite end of adsorber (A), chosen for the introduction of stream (S3) into the adsorber (A).The streams (S3) and (S5) are only present during operation mode.

[0135] The stream (S4) comprises at least the stream (S2) and/or compounds containing oxygen and/or sulfur. The stream (S4) is leaving the adsorber (A) during regeneration mode, in regeneration step b) of the process of the present invention, but not during operation mode of the adsorber (A). Stream (S4) may leave the adsorber according to or opposite to the direction of flow of stream (S3). Preferably stream (S4) leaves the adsorber during the steps b), b1), b2) and/or b3) opposite to the direction of flow of stream (S3) and/or during the steps c) and/or d) according to the direction of flow of stream (S3). Stream (S4) may additionally comprise (compared to stream (S2)) those elements (such as compounds containing oxygen and/or sulphur) which were adsorbed by the adsorber from stream (OC2) during its operation mode. (OC2) comprises at least one olefin and/or at least one alkane and at least one compound containing oxygen and/or sulphur.

[0136] For cooling of the adsorber, stream (S2) coming from the evaporation/heating unit (EHU) is passed according to the direction of flow of stream (S3) through the adsorber. The stream (S2*) leaving the adsorber during this step is at least partially routed back to the evaporation/heating unit (EHU) for reuse.

[0137] FIG. 2 demonstrates one possible embodiment, in which liquid stream (S2) is obtained by hydrogenation of stream (S1). The stream (S1) is fed into a hydrogenation reactor (HR). The outflow comprises liquid stream (S2) which is routed to the evaporation/heating unit (EHU).

[0138] In FIG. 3 one embodiment for the recirculation of liquid or gaseous stream (S2) for reuse is displayed in more detail; gaseous or liquid stream (S2) coming from heating/evaporation unit (EHU) is fed during cooling step d) according to the direction of flow of stream (S3) into the adsorber. The liquid or gaseous stream (S2) leaving the adsorber during cooling step d) is passed through a cooling unit (CU) and routed back to the evaporation/heating unit (EHU) by a pump (P). Cooling unit (CU) comprises at least one cooler and/or condenser which are serially connected and/or parallel-connected with each other.

[0139] FIG. 4 shows a further alternative embodiment for the recirculation of gaseous stream (S2*). Instead of condensing the outflow of the adsorber (S2*) before reuse, it is routed to the evaporation/heating unit (EHU), comprising additionally a jet compressor (JC). Gaseous stream (S2*) is directly connected with the (EHU) over a jet compressor (JC). From the jet compressor (JC) the stream (S2) is routed via a super heater (SH1) to the adsorber (A). Furthermore, one possible embodiment for the evaporation/heating unit (EHU) is shown in more detail. Liquid stream (S2) is fed into a flash vessel (FV) and routed from there directly and/or indirectly over an evaporator (EV) to the jet compressor (JC). The pressure of liquid stream (S2) provides the energy for the compression of gaseous stream (S2*), if a jet compressor (JC) is applied. However, in embodiments where no jet compressor (JC) or other compressor is incorporated in the assembly, stream (S2) may be passed, coming from the flash vessel (FV) or the evaporator (EV), directly to the super heater (SH1).