Claims:1. A reactive distillation column for conversion of syngas to dimethyl ether (DME), said reactive distillation column comprising:
a reactor, said reactor defining an inlet for the syngas and a bed of catalyst, said syngas upon coming in contact with the catalyst within said reactor being converted to an effluent stream having dimethyl ether (DME);
a first distillation column, said first distillation column being fed with the effluent stream from said reactor, affording separation of one or more gaseous streams rich in dimethyl ether (DME), CO2 and unreacted syngas from a condensate stream rich in water and methanol without allowing entry of said condensate stream in the reactor; and
a second distillation column, said second distillation column being fed with the condensate stream from said first distillation column, affording a water rich stream and a methanol rich gaseous stream, said methanol rich gaseous stream being fed along with the syngas to said reactor.

2. The reactive distillation column as claimed in claim 1, wherein said first distillation column defines one or more chimney trays affording collection of the condensate stream, precluding condensate stream from entering into the reactor while allowing entry of said effluent stream from said reactor to the first distillation column.

3. The reactive distillation column as claimed in claim 1, wherein said bed of catalyst is packed within tubes, and wherein a heat transfer media is circulated outside said tubes affording desired reactor temperature.

4. The reactive distillation column as claimed in claim 1, wherein said reactor or part thereof acts as a reboiler for said first distillation column affording removal of dissolved gases from said condensate stream.

5. The reactive distillation column as claimed in claim 1, wherein each of said reactor, said first distillation column and said second distillation column are configured as a single distillation column.

6. The reactive distillation column as claimed in claim 5, wherein said single distillation column does not define any physical blinding or isolation between said reactor, the first distillation column and the second distillation column.

7. A process for preparing dimethyl ether (DME) from syngas, said process comprising:
feeding the syngas to a reactor, said reactor defining an inlet for the syngas and a bed of catalyst, said syngas upon coming in contact with the catalyst within said reactor being converted to an effluent stream having dimethyl ether (DME);
feeding the effluent stream to a first distillation column, affording separation of one or more gaseous streams rich in dimethyl ether (DME), CO2 and unreacted syngas, and a condensate stream rich in water and methanol without allowing entry of said condensate stream into the reactor;
feeding the condensate stream from the first distillation column to a second distillation column, affording a water rich stream and a methanol rich gaseous stream;
feeding the methanol rich gaseous stream along with the syngas to said reactor; and
separating the one or more gaseous streams rich in dimethyl ether (DME), CO2 and unreacted syngas to obtain dimethyl ether (DME).
8. The process as claimed in claim 7, wherein the step of separating one or more gaseous streams from the condensate stream comprises: collecting the condensate stream on one or more chimney trays defined at bottom of the first distillation column affording precluding the entry of said condensate stream into said reactor while allowing entry of said effluent stream from said reactor to the first distillation column.
, Description:TECHNICAL FIELD
[0001] The present disclosure pertains to the technical field of production of dimethyl ether (DME). In particular, the present disclosure provides a reactive distillation column for conversion of syngas to DME. Aspects of the present disclosure also relates to a process for preparing dimethyl ether (DME) from syngas.

BACKGROUND OF THE INVENTION
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] With the increasing demand for cleaner fuel everyone started searching for alternate or cleaner fuels, as a part of which gas fuels are replacing the conventional liquid fuels. At the same time, India being a huge importer of LPG, an alternate fuel which can be blended with LPG or can fully replace LPG is to be explored. DME can be an answer for the above problems.
[0004] There are two processes for producing dimethyl ether (DME): one being direct conversion of syngas to DME, and another being firstly converting syngas to methanol and then effecting dehydration of methanol to produce DME. In both these reactions, the reaction proceeds as below:
----------------------- (1)
--------------------- (2)
------------------------ (3)
[0005] It is noteworthy that at an industrial/commercial scale, the direct conversion of syngas to DME is not preferred, and in-fact, not practiced, owing to the Water Gas Shift reaction occurring simultaneously, significantly lowering the overall yield of DME. Water Gas Shift reaction scheme is shown below:
------------------------ (4)
[0006] As can be seen from the reaction schemes presented hereinabove, whenever direct conversion of syngas to DME is attempted, the water generated at step 2 (along with methanol) and step 3 (along with DME) upon reacting with carbon monoxide of the syngas, generates CO2 and H2, extent whereof depends on the nature of the catalyst employed for effecting the conversion of syngas to DME. Hence, conventionally, the two step process is used for production of DME from syngas, wherein two different reactors or reactor beds or two different catalysts are employed, and once the first reaction is completed, the methanol and water are separated and the purified stream of methanol is fed to the second reactor for conversion to DME. In two step process, effect of water is dominated in methanol production step only, and the water produced during methanol production may or may not be removed simultaneously. The water produced during the second step (i.e. methanol dehydration) being carried out in a different reactor doesn’t affect reactions in step one (i.e. methanol production).
[0007] Rigorous research has been done so far to preclude and/or minimize the extent of competing Water Gas Shift reaction and numerous techniques and reactor configurations have been proposed so far, albeit with minimal or no success. For example, article of Guo F. et al. titled “Enhanced Dimethyl Ether Synthesis by Reactive Distillation in a Dividing-wall Column” published at 4th International Conference on Process Intensification for the Chemical Industry; Gough, M., Ed., 2001; pp 107-113 discloses a DME process based on methanol dehydration, taking place in a reactive dividing-wall column (DWC) that effectively integrates in one shell, a reactive distillation (RD) unit and an ordinary distillation column (shown in Figure 2 thereof), contents whereof are incorporated herein by way of reference. US patent US8378150B2 discloses a process to produce dimethyl ether from a methanol reactor effluent, contents whereof are incorporated herein by way of reference. The process includes contacting an aqueous extractant comprising water and an effluent from a methanol synthesis reactor comprising methanol and one or more of methane, water, carbon monoxide, carbon dioxide, hydrogen, and nitrogen. At least a portion of the methanol partitions into the aqueous extractant; recovering an extract fraction comprising the aqueous extractant and methanol. The extract fraction is fed to a catalytic distillation reactor system for concurrently: contacting the methanol with catalyst in a reaction zone thereby catalytically reacting at least a portion of the methanol to form dimethyl ether and water; and fractionating the resulting dimethyl ether and the water to recover a first overheads fraction comprising dimethyl ether and a first bottoms fraction comprising water. US Patent no. 6045762 describes about design of apparatus for catalytic distillation; US patent publication no. 2007/0095646A1 discloses a catalytic distillation apparatus; US patent No. 6723886 discloses catalytic distillation process in methanol production; US Patent no. 8575399B2 describes a catalytic distillation process for production of DME using methanol; US patent no. 9266804 discloses a catalytic distillation column with 2 catalyst beds with varying characteristics for production of DME using methanol; and US patent publication no. 2014/0364654d discloses a process for conversion of natural gas to DME, in which Natural gas is converted to methanol and then the methanol is fed to a catalytic distillation column for DME production, contents whereof are incorporated herein by way of reference. It can be readily appreciated from study of these (and such other) documents that numerous types of reactors have been proposed in the state-of-art for methanol dehydration reactions, but none of them attempts to effect direct conversion of syngas to DME, owing to production of diluted methanol stream (due to presence of water in the effluent stream), which if subjected directly (without separation of water therefrom) to the reactive distillation, would favour water gas shift reaction and DME productivity will be drastically lowered.
[0008] Hence, there remains a long felt need in the art of a reactive distillation column for conversion of syngas to DME and a process for preparing dimethyl ether (DME) from syngas that may overcome the drawbacks associated with the existing columns and processes, while offering significant economic advantage. The present invention satisfies the existing needs, as well as others, and generally overcomes the deficiencies found in the state-of-art.
[0009] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.

OBJECTS OF THE INVENTION
[0010] It is an object of the present disclosure to provide a reactive distillation column for conversion of syngas to dimethyl ether (DME).
[0011] It is another object of the present disclosure to provide a method for preparing dimethyl ether (DME) from syngas that is economical.

SUMMARY
[0012] The present disclosure pertains to the technical field of production of dimethyl ether (DME). In particular, the present disclosure provides a reactive distillation column for conversion of syngas to DME. Aspects of the present disclosure also relates to a process for preparing dimethyl ether (DME) from syngas.
[0013] An aspect of the present disclosure provides a reactive distillation column for conversion of syngas to dimethyl ether (DME), said reactive distillation column comprising: (a) a reactor, said reactor defining an inlet for the syngas and a bed of catalyst, said syngas upon coming in contact with the catalyst within said reactor being converted to an effluent stream having dimethyl ether (DME); (b) a first distillation column, said first distillation column being fed with the effluent stream from the reactor, affording separation of one or more gaseous streams rich in dimethyl ether (DME), CO2 and unreacted syngas, and a condensate stream rich in water and methanol without allowing entry of said condensate stream into the reactor; and (c) a second distillation column, said second distillation column being fed with the condensate stream from the first distillation column, affording a water rich stream and a methanol rich gaseous stream, said methanol rich gaseous stream being fed along with the syngas to said reactor.
[0014] In an embodiment, said first distillation column defines one or more chimney trays affording collection of the condensate stream, precluding condensate stream from entering in the reactor zone while allowing entry of said effluent stream from said reactor to the first distillation column. In an embodiment, said bed of catalyst is packed within tubes, and wherein a heat transfer media is circulated outside said tubes affording desired reactor temperature. In an embodiment, said reactor or part thereof acts as a reboiler for said first distillation column affording removal of dissolved gases from said condensate stream. In an embodiment, each of said reactor, said first distillation column and said second distillation column are configured as a single distillation column. In an embodiment, said single distillation column does not define any physical blinding or isolation between said reactor, the first distillation column and the second distillation column. In an embodiment, said bed of catalyst is a fixed bed of catalyst. In an embodiment, said catalyst includes DME catalyst.
[0015] Another aspect of the present disclosure relates to a process for preparing dimethyl ether (DME) from syngas, said process comprising: (a) feeding the syngas to a reactor, said reactor defining an inlet for the syngas and a bed of catalyst, said syngas upon coming in contact with the catalyst within said reactor being converted to an effluent stream having dimethyl ether (DME); (b) feeding the effluent stream to a first distillation column, affording separation of one or more gaseous streams rich in dimethyl ether (DME), CO2 and unreacted syngas, and a condensate stream rich in water and methanol without allowing entry of said condensate stream in the reactor; (c) feeding the condensate stream to a second distillation column, affording a water rich stream and a methanol rich gaseous stream; (d) feeding the methanol rich gaseous stream along with the syngas to said reactor; and (e) separating the one or more gaseous streams rich in dimethyl ether (DME), CO2 and unreacted syngas to obtain dimethyl ether (DME). In an embodiment, the step of separating one or more gaseous streams from the condensate stream comprises: collecting the condensate stream on one or more chimney trays defined at bottom of the first distillation column affording precluding the entry of said condensate stream into said reactor while allowing entry of said effluent stream from said reactor to the first distillation column.
[0016] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The accompanying drawings are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.
[0018] FIG. 1illustratesan exemplary schematic of a reactive distillation column for conversion of syngas to dimethyl ether (DME), realized in accordance with an embodiment of the present disclosure.
[0019] FIG. 2 illustrates an exemplary schematic of a configuration of the reactive distillation column, realized in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION
[0020] The following is a detailed description of embodiments of the present invention. The embodiments are in such detail as to clearly communicate the invention. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present invention as defined by the appended claims.
[0021] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the “invention” may in some cases refer to certain specific embodiments only. In other cases it will be recognized that references to the “invention” will refer to subject matter recited in one or more, but not necessarily all, of the claims.
[0022] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability.
[0023] Unless the context requires otherwise, throughout the specification which follow, the word “comprise” and variations thereof, such as, “comprises” and “comprising” are to be construed in an open, inclusive sense that is as “including, but not limited to.”
[0024] Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
[0025] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0026] In some embodiments, the numbers expressing quantities of ingredients, properties such as concentration, and so forth, used to describe and claim certain embodiments of the invention are to be understood as being modified in some instances by the term “about.” Accordingly, in some embodiments, the numerical parameters set forth in the written description are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable.
[0027] The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein.
[0028] The headings and abstract of the invention provided herein are for convenience only and do not interpret the scope or meaning of the embodiments.
[0029] All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
[0030] The following discussion provides many example embodiments of the inventive subject matter. Although each embodiment represents a single combination of inventive elements, the inventive subject matter is considered to include all possible combinations of the disclosed elements. Thus if one embodiment comprises elements A, B, and C, and a second embodiment comprises elements B and D, then the inventive subject matter is also considered to include other remaining combinations of A, B, C, or D, even if not explicitly disclosed.
[0031] Various terms as used herein are shown below. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.
[0032] The present disclosure pertains to the technical field of production of dimethyl ether (DME). In particular, the present disclosure provides a reactive distillation column for conversion of syngas to DME. Aspects of the present disclosure also relates to a process for preparing dimethyl ether (DME) from syngas.
[0033] An aspect of the present disclosure provides a reactive distillation column for conversion of syngas to dimethyl ether (DME), said reactive distillation column comprising: (a) a reactor, said reactor defining an inlet for the syngas and a bed of catalyst, said syngas upon coming in contact with the catalyst within said reactor being converted to an effluent stream having dimethyl ether (DME); (b) a first distillation column, said first distillation column being fed with the effluent stream, affording separation of one or more gaseous streams rich in dimethyl ether (DME), CO2 and unreacted syngas, and a condensate stream rich in water and methanol without allowing entry of said condensate stream into the reactor; and (c) a second distillation column, said second distillation column being fed with the condensate stream, affording a water rich stream and a methanol rich gaseous stream, said methanol rich gaseous stream being fed along with the syngas to said reactor.
[0034] In an embodiment, said first distillation column defines one or more chimney trays affording collection of the condensate stream, precluding condensate stream from entering in the reactor zone while allowing entry of said effluent stream from said reactor to the first distillation column. In an embodiment, said bed of catalyst is packed within tubes, and a heat transfer media (also referred to as “thermal media” alternatively and synonymously) is circulated outside said tubes affording desired reactor temperature. In an embodiment, said reactor or part thereof acts as a reboiler for said first distillation column affording removal of dissolved gases from said condensate stream. In an embodiment, each of said reactor, said first distillation column and said second distillation column are configured as a single distillation column. In an embodiment, said single distillation column does not define any physical blinding or isolation between said reactor, the first distillation column and the second distillation column. In an embodiment, said bed of catalyst is a fixed bed of catalyst. In an embodiment, said catalyst includes DME catalyst.
[0035] FIG. 1 illustrates an exemplary schematic of a reactive distillation column for conversion of syngas to dimethyl ether (DME), realized in accordance with an embodiment of the present disclosure. As can be seen from FIG. 1, the reactive distillation column (100) includes: a reactor (110), said reactor defining an inlet for the syngas (102) and a bed of catalyst (104), said syngas upon coming in contact with the catalyst within said reactor being converted to an effluent stream having dimethyl ether; a first distillation column (120), said first distillation column (120) being fed with the effluent stream from the reactor (110), affording separation of one or more gaseous streams rich in dimethyl ether (DME), CO2 and unreacted syngas (shown as two streams titled “Gases” and “DME”), and a condensate stream rich in water and methanol without allowing entry of said condensate stream in the reactor (110); and a second distillation column (130), said second distillation column (130) being fed with the condensate stream from the first distillation column (120), affording a water rich stream and a methanol rich gaseous stream (shown as two streams titled “Methanol” and “Water”), said methanol rich gaseous stream being fed along with the syngas to said reactor.
[0036] As can be seen from FIG. 1, first distillation column (120) defines one or more chimney trays (140) affording collection of the condensate stream, precluding condensate stream from entering in the reactor zone (110) while allowing entry of said effluent stream from said reactor (110) to the first distillation column (120). As can also be seen from FIG. 1, the bed of catalyst (104) is packed within tubes (104a), and a heat transfer media (105) is circulated outside (surrounding) said tubes affording desired reactor temperature. The heat transfer media (105) may be water such as hot or boiling water, chilled water, a refrigerant or such other conventional heat transfer medium that can aid in achieving and/or maintaining the desired reactor temperature. As can also be seen from FIG. 1, each of the reactor (110), the first distillation column (120) and the second distillation column (130) are configured as a single distillation column without defining any physical blinding or isolation therebetween. It should be appreciated that in case of mechanical/space constraints, the three components (2 distillation columns and reactor) may be installed separately, wherein they can be identified as three individual projections on the ground, however, they may be connected in a similar fashion so as to meet the desired process flow and act in a manner akin to a single column. Accordingly, in an embodiment, the reactive distillation column is a combination of a reactor and two distillation columns, wherein the reactor (or the reaction zone) is placed intermittently between two distillation columns or zones (for example, one distillation column or zone above the reactor and another distillation column or zone below the reactor).
[0037] The syngas (Feed) is fed to the column (100) at the bottom of the reactor (110) where it comes in contact with the catalyst (104). The catalyst can be as known to or appreciated by a person skilled in the art, such as bifunctional catalyst that affords conversion of syngas to DME. The reactor (110) can be a multi-tubular reactor wherein the catalyst (104) may be packed in the tubes (104a) and the heat transfer media (105) may be circulated surrounding the tubes (104a) so as to heat or cool the reactor zone such that the desired temperature may be achieved and/or maintained. The syngas upon coming in contact with the catalyst gets converted into the product DME. The effluent stream leaving the reactor (110) zone contains unreacted syngas, DME, methanol, water and CO2. The effluent stream is typically in form of a gaseous stream and leaves from top of the reactor and enters in the first distillation column (120) from its bottom. In the first distillation column (120), one or more gaseous streams rich in dimethyl ether (DME), CO2 and unreacted syngas and a condensate stream rich in water and methanol are separated. For example, one gaseous stream rich in DME, CO2 and unreacted syngas may leave from the top of the first distillation column, which may be subjected to further separation and purification to obtain DME of requisite purity. Alternatively, a stream partially enriched with DME may be separately taken out as a side cut, apart from the top cut stream including CO2, unreacted syngas and unrecovered DME and a bottom condensate stream rich in methanol and water. It is noteworthy that the condensate stream from the first distillation column (120) cannot be directly fed or trickled down into reactor (110) due to the presence of water in the condensate stream (which otherwise favors water gas shift reaction). Hence, the condensate stream rich in methanol and water is collected and fed to the second distillation column (130) without allowing entry of the condensate stream in the reactor. As can be seen from FIG. 1, in an embodiment, the first distillation column (120) defines one or more chimney trays (140) affording collection of the condensate stream, precluding condensate stream from entering in the reactor zone (110) while allowing entry of said effluent stream from said reactor (110) to the first distillation column (120). Alternatively, any other technique or means may be used to serve its intended purpose i.e. to preclude the condensate stream from coming in the reactor zone. The second distillation column (130) separates water from the condensate stream as bottoms and the methanol vapors along with dissolved gases leave from the top, which may be mixed with the fresh feed (i.e. the syngas).
[0038] Simply put, the unconverted methanol is purified and is being recycled back to the reactor significantly enhancing the DME production without any need of additional process units or recycle streams, which are inevitably employed in various schemes proposed in the state-of-art. As DME production is being enhanced with reduced downstream units, the capital and operating expenses significantly get reduced, further boosting the DME economics - in a step towards making the DME a viable substitute for LPG and Diesel. The entire reactive distillation column may operate at pressures required for the reactor and may not involve any compression system for boosting the pressure inside the reactor. There is no physical blinding or isolation between each sections, giving a leverage to a particular section for operating at temperatures and pressures that does not affect column continuity across the sections.
[0039] FIG. 2 illustrates an exemplary schematic of a configuration of the reactive distillation column, realized in accordance with an embodiment of the present disclosure. As can be seen from FIG. 2, the reactor (110) or part thereof acts as a reboiler for the first distillation column (120) aiding removal of dissolved gases from the condensate stream. The condensate stream (bottoms) collected from the reboiler (reactor utility side) are fed to the second distillation column (130). The second distillation column (130) separates water from the condensate stream as bottoms and the methanol vapors along with dissolved gases leave from the top, which may be mixed with the fresh feed (i.e. the syngas).
[0040] Another aspect of the present disclosure relates to a process for preparing dimethyl ether (DME) from syngas, said process comprising: (a) feeding the syngas to a reactor, said reactor defining an inlet for the syngas and a bed of catalyst, said syngas upon coming in contact with the catalyst within said reactor being converted to an effluent stream having dimethyl ether (DME); (b) feeding the effluent stream to a first distillation column, affording separation of one or more gaseous streams rich in dimethyl ether (DME), CO2 and unreacted syngas, and a condensate stream rich in water and methanol without allowing entry of said condensate stream in the reactor; (c) feeding the condensate stream from the first distillation column to a second distillation column, affording a water rich stream and a methanol rich gaseous stream; (d) feeding the methanol rich gaseous stream along with the syngas to said reactor; and (e) separating the one or more gaseous streams rich in dimethyl ether (DME), CO2 and unreacted syngas to obtain dimethyl ether (DME). In an embodiment, the step of separating one or more gaseous streams from the condensate stream comprises: collecting the condensate stream on one or more chimney trays defined at bottom of the first distillation column affording precluding the entry of said condensate stream into said reactor while allowing entry of said effluent stream from said reactor to the first distillation column.
[0041] While the foregoing description discloses various embodiments of the disclosure, other and further embodiments of the invention may be devised without departing from the basic scope of the disclosure. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.
[0042] Example 1 –
[0043] Table 1 below provides specifics of a reactive distillation column and operating parameters thereof for conversion of syngas to dimethyl ether (DME).
Table 1: Specifics of a reactive distillation column and operating parameters
Equipment details Without methanol drawoff With methanol drawoff
Equipment number Section A
(120) Section B
(130) Section A
(120) Section B
(130)
Temperature
Condenser / top 101.30 204.97 95.43 203.45
Reboiler / bottom 195.30 252.42 194.35 261.44
Pressure (bar) 50.00 50.00 50.00 50.00
Number of Stages 10.00 20.00 10.00 20.00
Distillate rate (Kmoles / hr) 46.15 13.85 44.85 12.12
Reflux rate (Kmoles / hr) 58.60 29.23 62.03 319.32
Reflux ratio 1.27 2.11 1.38 26.34
Bottoms rate (kmoles / hr) 39.06 25.21 38.63 23.60
Boilup rate (kmoles / hr) 97.14 37.80 95.39 240.84
Boilup ratio 2.49 1.50 2.47 10.21
Methanol drawoff tray number NA NA NA 2.00
Methnaol draw off flowrate (Kg/hr) NA NA NA 93.00
Methnaol draw off flowrate (Kmole/hr) NA NA NA 2.91

[0044] Table 2 below provides operating parameters of the reactive distillation column along with composition (in mole fraction) of different feed/streams when the reactive distillation column is operated without methanol drawoff from Section B (distillation column 130)while effecting conversion of syngas to dimethyl ether (DME).

Table 2: Operating parameters and composition of different feed/streams (without methanol drawoff)
Stream Details Feed feed after mixing with methanol from Section B reactor effluents entering section A Gases Condensate Water Methanol fed back to reactor
Flowrate (Kg / hr) 1811.09 2271.09 2271.09 1340.00 931.09 471.09 460.00
Flowrate (Kmoles / hr) 150.00 163.85 85.21 46.15 39.06 25.21 13.85
Temperature ( °C ) 250.00 242.83 250.00 101.30 195.30 252.42 204.97
Pressure (Bar) 55.00 50.00 61.01 50.00 50.00 50.00 50.00
Composition (%)
METHANOL 0 7 18 5 33 5 83
WATER 0 0 29 0 63 95 3
DME 0 1 23 39 4 0 12
H2 65 60 15 27 0 0 0
CO 29 27 12 23 0 0 1
CO2 6 06 3 6 0 0 0

[0045] Table 3 below provides operating parameters of the reactive distillation column along with composition (in mole fraction) of different feed/streams when the reactive distillation column is operated with methanol drawoff from Section B (distillation column 130) while effecting conversion of syngas to dimethyl ether (DME).

Table 3: Operating parameters and composition of different feed/streams (with methanol drawoff)
Stream Details Feed Feed after mixing with methanol from Section B Reactor effluents entering section A Gases Condensate Methanol Water Methanol fed back to reactor
Flowrate (Kg / hr) 1811.09 2221.09 2221.09 1290.00 931.09 93.00 428.09 410.00
Flowrate (Kmoles / hr) 150.00 162.12 83.48 44.85 38.63 2.91 23.60 12.12
Temperature ( C ) 250.00 243.28 250.00 95.43 194.35 210.67 261.44 203.45
Pressure (Bar) 55.00 50.00 61.01 50.00 50.00 50.00 50.00 50.00
Composition (%)
METHANOL 0 6 18 4 35 99 1 85
WATER 0 0 28 0 61 1 99 0
DME 0 1 23 38 4 0 0 13
H2 65 60 15 28 0 0 0 0
CO 29 27 13 23 0 0 0 1
CO2 6 6 3 6 0 0 0 1

[0046] Table 4 below provides stream data of the finished products along with composition (in mole fraction) of different feed/streams when the reactive distillation column is operated with methanol drawoff from Section B (distillation column 130) while effecting conversion of syngas to dimethyl ether (DME).

Table 4: Stream data of finished products
Stream Details Without methanol drawoff With methanol drawoff
Recycle Gas DME Methanol Recycle Gas DME Methanol
Flowrate (Kg / hr) 97.42 640.00 79.60 91.03 610.00 150.00
Flowrate (Kmoles / hr) 2.38 13.90 2.49 2.22 13.25 4.69
Temperature ( C ) 30.02 58.41 153.12 29.97 59.17 153.33
Pressure (Bar) 15.00 15.00 15.00 15.00 15.00 15.00
Composition (%)
METHANOL 0 0 100 0 0 99
WATER 0 0 0 0 0 1
DME 42 99 0 41 99 0
H2 2 0 0 2 0 0
CO 18 0 0 18 0 0
CO2 38 1 0 39 0 0

[0047] COMPARISON WITH CONVENTIONAL PROCESS
[0048] Table 5 below shows comparison between reactive distillation in accordance with the present disclosure (without methanol drawoff from reactor) versus the conventional process. Table 6 below shows comparison between reactive distillation in accordance with the present disclosure (with methanol drawoff from Section B/distillation column 130) versus the conventional process.

Table 5: Reactive Distillation (without methanol drawoff) vs. Conventional process
Reactive Distillation
(Without methanol drawoff from reactor) Conventional Process
Stream Details Feed
Reactor Outlet Streams Final Product Streams Reactor Outlet Final Product Streams
Gases Condensate Water DME Methanol Water DME Methanol Water
Flowrate
(Kg / hr) 1811.09 1340.00 931.09 471.09 640.00 79.60 471.09 2119.14 649.39 539.91 377.03
Flowrate (Kmoles / hr) 150.00 46.15 39.06 25.21 13.90 2.49 25.21 99.19 14.10 16.80 20.93
Temperature (° C ) 250.00 101.30 195.30 252.42 58.41 153.12 252.42 250.00 44.69 83.07 120.69
Pressure (Bar) 55.00 50.00 50.00 50.00 15.00 15.00 50.00 61.01 10.13 2.03 2.03
Composition (%)
METHANOL 0 5 33 5 0 100 5 17 0 99 0
WATER 0 0 63 95 0 0 95 21 0 0 100
DME 0 39 4 0 99 0 0 15 99 1 0
H2 65 27 0 0 0 0 0 32 0 0 0
CO 29 23 0 0 0 0 0 12 0 0 0
CO2 6 6 0 0 1 0 0 3 1 0 0

Table 6: Reactive Distillation (with methanol drawoff) vs. Conventional process
Stream Details Feed Reactive Distillation Conventional Process
with methanol drawoff from reactor
Reactor Outlet Streams Final Product Streams Reactor Outlet Final Product Streams
Gases Condensate Methanol Water DME Methanol Water DME Methanol Water
Flowrate
(Kg / hr) 1811.09 1290.00 931.09 93.00 428.09 610.00 150.00 428.09 2119.14 649.39 539.91 377.03
Flowrate (Kmoles / hr) 150.00 44.85 38.63 2.91 23.60 13.25 4.69 23.60 99.19 14.10 16.80 20.93
Temp. ( °C ) 250.00 95.43 194.35 210.67 261.44 59.17 153.33 261.44 250.00 44.69 83.07 120.69
Pressure (Bar) 55.00 50.00 50.00 50.00 50.00 15.00 15.00 50.00 61.01 10.13 2.03 2.03
Composition (%)
METHANOL 0 4 35 99 1 0 99 1 17 0 99 0
WATER 0 0.00 61 1 99 0 1 99 21 0 0 100
DME 0 38 4 0 0 99 0 0 15 99 1 0
H2 65 28 0 0 0 0 0 0 32 0 0 0
CO 29 23 0 0 0 0 0 0 12 0 0 0
CO2 6 6 0 0 0 0 0 0 3 1 0 0

[0049] From compositions, as shown in Table 5, it is evident that DME concentration at reactor outlet (col. No. 3) was about 39%, while that in case of conventional process was about 15%. Although the same catalyst was used, this increase in conversion could be attained plausibly owing to reduced methanol concentration, wherein, at reactor outlet (col. 3) methanol was about 5% and in case of conventional process methanol was about 17%. The same is also evident from col. 7 and 11, wherein using reactive distillation column 79.60 kg/hr of methanol could be produced and in case of conventional process 539.91 Kg/hr of methanol could be produced.
[0050] From compositions, as shown in Table 6, it is evident that DME concentration at reactor outlet (col. No. 3) was about 38%, while that in case of conventional process was about 15%. Although the same catalyst was used, this increase in conversion could be attained plausibly owing to reduced methanol concentration, wherein, at reactor outlet (col. 3) methanol was about 4% and in case of conventional process methanol was about 17%. The same is also evident from col. 7 and col. 11, wherein using reactive distillation column about 150 kg/hr of methanol could be produced and in case of conventional process 539.91 Kg/hr of methanol could be produced.

ADVANTAGES
[0051] The present disclosure provides a reactive distillation column for conversion of syngas to dimethyl ether (DME).
[0052] The present disclosure provides a process for preparing dimethyl ether (DME) from syngas that is economical.