Description:FIELD OF INVENTION
[001] The present invention is related to an integrated and energy efficient catalytic process for the oxidative dehydrogenation of propane using captured CO2 as a soft oxidant. The process yields propylene, a valuable feedstock for numerous industrial applications, which is then subjected to hydroformylation to produce butyraldehydes. More specifically, the process effectively utilizes refinery grade propylene and syngas without any additional separation, thus minimizing energy consumption and reducing the overall CO2 footprint of the process. This innovative approach leverages the use of readily available natural gas sources, and pollutant gas CO2, to produce high-value chemicals, contributing to the sustainability of the chemical industry.

BACKGROUND OF THE INVENTION
[002] 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.
[003] Olefin hydrocarbons are useful for the production of a number of petrochemical products, such as polymers, motor fuel blending additives, and other products. Short chain saturated hydrocarbons having from 2 to 5 carbon atoms per molecule are often subjected to dehydrogenation to form the corresponding olefin. The olefins, in turn, may be used in the alkylation of isoparaffms, in the etherification of alcohols to make motor fuel blending additives, or as monomers used to produce various polymer materials.
[004] Propylene is a critical reactant for the production of oxo chemicals on an industrial scale, comprising roughly 75% of global consumption. However, relying solely on the co-production of propylene from FCC and steam cracking processes will lead to a shortage in supply. Therefore, the development of an on-purpose propylene production method, in combination with syngas production, could yield valuable feedstocks for hydroformylation products.
[005] The same may be achieved by effectively utilizing the two streams of propane and captured CO2 through the use of a suitable catalyst system under optimal reaction conditions. This approach presents an opportunity to address the potential demand gap in propylene supply and provide a sustainable solution for the production of hydroformylation feedstocks.
[006] The dehydrogenation of propane is an energy-intensive and equilibrium-limited process. The addition of an oxidant, such as O2, can significantly enhance the reaction extent even at lower severity, albeit at the expense of product selectivity. However, it is possible to strike a balance between these conflicting factors by employing a mild oxidant, such as captured CO2, thereby promoting both increased reaction extent and improved product selectivity. The approach in the present disclosure not only enhances process efficiency but also contributes to the net-zero efforts of the industry, thereby furthering the goal of sustainable production.
[007] The present disclosure provides an integrated and energy efficient catalytic process for the oxidative dehydrogenation of propane using CO2 as a soft oxidant. The process yields propylene, a valuable feedstock for numerous industrial applications, which is then subjected to hydroformylation to produce butyraldehydes. The system effectively utilizes refinery grade propylene and syngas without any additional separation, thus minimizing energy consumption and reducing the overall CO2 footprint of the process. This innovative approach leverages the use of readily available natural gas sources, and pollutant gas CO2 to produce high-value chemicals, contributing to the sustainability of the chemical industry.

OBJECTS OF THE INVENTION
[008] The primary objective of the present invention is to provide an integrated and energy efficient process for the oxidative dehydrogenation of propane using captured CO2 as a soft oxidant.
[009] An object of the present invention is to provide a process where Endothermic dehydrogenation and exothermic hydroformylation processes are linked together to reduce energy expenditure.
[0010] An object of the present inventive is to provide an integrated process wherein the absence of separator/splitters and purification steps leads to a significant reduction in the energy footprint.
[0011] Another object of the present invention is to provide an integrated process to produce n-butyraldehyde and i-butyraldehyde, which are valuable end-products.
[0012] Another objective of the present invention is provide an integrated process which utilizes readily available natural gas sources, and pollutant gas CO2, to produce high-value chemicals, contributing to the sustainability of the chemical industry.
[0013] Another object of the present invention is to provide an integrated process which utilizes CO2 as a mild oxidant to improve the equilibrium of the propane dehydrogenation reaction and simultaneously produce syngas to be used in the subsequent hydroformylation step.

SUMMARY
[0014] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in Detailed Description section. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
[0015] According to one aspect of the present disclosure a process for oxidative dehydrogenation of propane followed by hydroformylation is disclosed. Said process comprises the following steps:
a) feeding propane and CO2 to the dehydrogenator reactor to obtain a gas mixture consisting of unconverted propane, propylene, syngas, and CO2;
b) feeding the dehydrogenation gas mixture directly to the hydroformylation reactor to produce n-butyraldehyde and i-butyraldehyde;
c) routing the unconverted propane and CO2 back to the dehydrogenation reactor.
[0016] In some embodiments, the Dehydrogenation step is carried out at a temperature between 500? to 600?.
[0017] In some embodiments, the stream from the hydroformylation reactor is fed to the flash distillation unit to obtain butyraldehydes and recover propylene and the catalyst.
[0018] In some embodiments, the stream from the hydroformylation reactor is used to preheat the propane stream which is feedstock to the oxidative dehydrogenation reactor via Heat Exchanger (HE1).
[0019] In some embodiments, the top product from the flash column is recycled back to hydroformylation reactor to reduce the temperature of dehydrogenation gas mixture via Heat Exchanger (HE2).
[0020] In some embodiments, the recovered catalyst and propylene are recycled back to the hydroformylation reactor.
[0021] In some embodiments, the process is a continuous process.
[0022] In some embodiments, the process effectively utilizes refinery grade propylene and syngas without any additional separation.
[0023] In some embodiments, the process minimizes energy consumption and reduces the overall CO2 footprint of the process.
[0024] In some embodiments, the process utilizes CO2 as a mild oxidant to improve the equilibrium of the propane dehydrogenation reaction and simultaneously produce syngas to be used in the subsequent hydroformylation step.
[0025] Various objects, features, aspects and advantages of the present disclosure will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like features

BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The accompanying drawing(s) 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. The diagrams are for illustration only, which thus is not a limitation of the present disclosure.
[0027] FIG. 1 illustrates a schematic flow diagram of a conventional process for oxidative dehydrogenation of propane followed by hydroformylation.
[0028] FIG. 2 illustrates a schematic flow diagram of an Integrated Process for oxidative dehydrogenation of propane and hydroformylation
[0029] FIG. 3 illustrates a schematic flow diagram of heat exchanger network (HEN) in the Integrated Process for oxidative dehydrogenation of propane and hydroformylation.

DETAILED DESCRIPTION OF THE INVENTION
[0030] The following is a detailed description of embodiments of the disclosure. The embodiments are in such detail as to clearly communicate the disclosure. 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 disclosure as defined by the appended claims.
[0031] 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.
[0032] 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.
[0033] In some embodiments, numbers have been used for quantifying weights, percentages, ratios, and so forth, to describe and claim certain embodiments of the invention and 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 and attached claims 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.
[0034] The numerical values presented in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
[0035] Unless the context requires otherwise, throughout the specification which follows, 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.”
[0036] 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.
[0037] The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein.
[0038] All methods described herein can be performed in a 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.
[0039] 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. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified.
[0040] The description that follows, and the embodiments described therein, is provided by way of illustration of an example, or examples, of particular embodiments of the principles and aspects of the present disclosure. These examples are provided for the purposes of explanation, and not of limitation, of those principles and of the disclosure.
[0041] It should also be appreciated that the present disclosure can be implemented in numerous ways, including as a system, a method or a device. In this specification, these implementations, or any other form that the invention may take, may be referred to as processes. In general, the order of the steps of the disclosed processes may be altered within the scope of the invention.
[0042] The headings and abstract of the invention provided herein are for convenience only and do not interpret the scope or meaning of the embodiments.
[0043] 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.
[0044] The term "or", as used herein, is generally employed in its sense including "and/or" unless the content clearly dictates otherwise.
[0045] Various terms are used herein to the extent a term used 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.
[0046] According to one aspect of the present disclosure a process for oxidative dehydrogenation of propane followed by hydroformylation is disclosed. Said process comprising the following steps:
a) feeding propane and CO2 to the dehydrogenator reactor to obtain a gas mixture consisting of unconverted propane, propylene, syngas, and CO2;
b) feeding the dehydrogenation gas mixture directly to the hydroformylation reactor to produce n-butyraldehyde and i-butyraldehyde;
c) routing the unreactive propane and CO2 back to the dehydrogenation reactor.
[0047] In some embodiments, the Dehydrogenation step is carried out at a temperature between 500? to 600?.
[0048] In some embodiments, the Dehydrogenation step is carried out at a temperature of 500?
[0049] In some embodiments, the stream from the hydroformylation reactor is fed to the flash distillation unit to obtain butyraldehydes and recover propylene and the catalyst.
[0050] In some embodiments, the stream from the hydroformylation reactor is used to preheat the propane stream which is feedstock to the oxidative dehydrogenation reactor via Heat Exchanger (HE1).
[0051] In some embodiments, the top product from the flash column is recycled back to hydroformylation reactor to reduce the temperature of dehydrogenation gas mixture via Heat Exchanger (HE2).
[0052] In some embodiments, the recovered catalyst and propylene are recycled back to the hydroformylation reactor.
[0053] In some embodiments, the process is a continuous process.
[0054] In some embodiments, the process effectively utilizes refinery grade propylene and syngas without any additional separation.
[0055] In some embodiments, the process minimizes energy consumption and reduces the overall CO2 footprint of the process.
[0056] In some embodiments, the process utilizes CO2 as a mild oxidant to improve the equilibrium of the propane dehydrogenation reaction and simultaneously produce syngas to be used in the subsequent hydroformylation step.
[0057] The present disclosure provides an integrated process that involves the catalytic dehydrogenation of propane in the presence of CO2 to produce a gas mixture consisting of propane, propylene, syngas, and CO2. This gas mixture is then subjected to hydroformylation to produce n-butyraldehyde and i-butyraldehyde, which are valuable end-products. To ensure sustainability, unreactive propane and CO2 are recycled back to the dehydrogenation reactor. The absence of splitters and purification steps in the integrated system leads to a significant reduction in the energy footprint. Endothermic dehydrogenation and exothermic hydroformylation processes are linked together to reduce energy expenditure. The process has been optimized using ASPEN simulations to enable efficient heat integration, process design, and energy usage while minimizing the CO2 footprint.
[0058] Results from the simulation indicate an energy benefit of 68% and a reduction in CO2 emissions of 1287 KTPA, further demonstrating the potential of the integrated process of the present disclosure as an effective and sustainable solution for producing valuable chemicals.
[0059] It would be apparent to a person skilled in the art that conventionally after the dehydrogenation reactor, the products are separated using large fractionators to separate the unreacted products for recycling. FIG. 1 illustrates a schematic flow diagram of a conventional process for oxidative dehydrogenation of propane.
[0060] The separation process is highly energy intensive since the dehydrogenation products are in gaseous state at STP and have close boiling points. Hence considerable energy is required as cooling duty thereby increasing the operating costs. Such super fractionators that separate close boiling components also have a high number of stages which further increases its capital cost.
[0061] The integrated process of the present disclosure eliminates the separation stage entirely and integrates the dehydrogenation and hydroformylation reactors as shown below. FIG. 2 illustrates a schematic flow diagram of an Integrated Process according to the present disclosure.
[0062] The combined dehydrogenation product mixture is directly fed to the hydroformylation reactor eliminating the requirement of an intermediate fractionator entirely. This significantly reduces the energy required by the entire process. There is another benefit in feeding the oxidative dehydrogenation product mixture as is via some heat exchange in the hydroformylation reactor. The reactants for hydroformylation are diluted due to presence of unreacted propane in the mixture. This propane acts as a heat sink for the highly exothermic hydroformylation reaction. This shifts the equilibrium favorably and increases the conversion.
[0063] The exothermic heat generated due to hydroformylation is used effectively in the endothermic dehydrogenation reaction via heat exchanger network (HEN), thereby further reducing the energy footprint of the process. FIG. 3 illustrates a schematic flow diagram of heat exchanger network (HEN) in the Integrated Process according to the present disclosure.
[0064] The hydroformylation reaction is highly exothermic. The product butyraldehyde is liquid at STP hence the unreacted gasses can be easily separated via a flash separator. For effective separation, the product must be cooled. This stream is therefore used to preheat the propane stream which is feedstock to the oxidative dehydrogenation reactor via HE1. Dehydrogenation is a highly endothermic process typically occurring between 500? to 600?, the heat exchange will reduce the heat duty needed for this reaction.
[0065] Hydroformylation is an exothermic reaction. Hence reducing the feed temperature to 70? to 90? will favor the equilibrium conversion. The product from the dehydrogenation reactor is at a relatively higher temperature. This stream can be quenched using the top product of the flash column via HE2. This will stop any side reactions occurring in the dehydrogenation product stream as well as improve the equilibrium conversion in the hydroformylation step.
Basis: 22000 kg/hr
Energy Kcal/sec Conventional Process
(Figure 1) Integrated Process without Heat exchange Integrated Process of the present disclosure (Figure 3)
OPDH Heater 6838.277 6838.277 4449.315
OPDH Reactor 9603.205 9603.205 9603.205
OPDH Product quench 7547.936 7547.936 NA
Separator 66414.923 NA NA
HF Reaction -2025.793 -2025.793 -2025.793
Flash Distillation 604.777 604.777 604.777
88983.33 22568.4 12631.5
Savings (Kcal/sec) 66414.92 76351.8
Table 1: Energy saved in the process according to the present disclosure.

[0066] Energy saved in this process is shown in the table above. The majority of energy saving is due to the elimination of the Separator which had significant reboiler and condenser duty. The remaining energy saving is due to preheating and quenching the oxidative dehydrogenation feed and product using heat exchangers. The lower energy requirement translates to lower carbon emissions and taking into consideration the CO2 being utilized in this process, this process is environmentally sustainable.
[0067] The yield pattern for the Oxidative propane dehydrogenation (OPDH) is shown below.
• Temperature: 500°C
• Weight Hourly Space Velocity: 3302h-1

OPDH IN OUT
PROPANE 33 16
PROPENE - 9
CO2 67 42
CO - 17
H2O - 6
H2 - 11
Table 2: Yield pattern for the Oxidative propane dehydrogenation (OPDH)

[0068] The yield pattern for the Hydroformylation (HF) is shown below.

HF IN OUT
PROPANE 16 19
PROPENE 9 0
CO2 42 51
CO 17 3
H2O 6 7
H2 11 2
IBA - 5
NBA - 12
Table 3: Yield pattern for the Hydroformylation (HF). It will be apparent to a person skilled in the art that all the propylene formed in the Oxidative propane dehydrogenation (OPDH) step is consumed in the hydroformylation

[0069] The foregoing examples are merely illustrative and are not to be taken as limitations upon the scope of the invention. Various changes and modifications to the disclosed embodiments will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the scope of the invention.

ADVANTAGES OF THE INVENTION
[0070] The present disclosure provides an integrated and energy efficient process for the oxidative dehydrogenation of propane using CO2 as a soft oxidant.
[0071] The present disclosure provides an integrated process where Endothermic dehydrogenation and exothermic hydroformylation processes are linked together to reduce energy expenditure.
[0072] The present disclosure provides an integrated process wherein the absence of splitters and purification steps leads to a significant reduction in the energy footprint.
[0073] The present disclosure provides an integrated process to produce n-butyraldehyde and i-butyraldehyde, which are valuable end-products.
[0074] The present disclosure provides an integrated process which utilizes readily available natural gas sources, and pollutant gas CO2, to produce high-value chemicals, contributing to the sustainability of the chemical industry.
[0075] The present disclosure provides an integrated process which utilizes CO2 as a mild oxidant to improve the equilibrium of the propane dehydrogenation reaction and simultaneously produce syngas to be used in the subsequent hydroformylation step.
[0076] Although the present invention has been described with reference to preferred embodiments, it is submitted that various modifications can be made to the exemplary embodiments without departing from the spirit and scope of the invention.
, Claims:1. An integrated catalytic process for oxidative dehydrogenation of propane followed by hydroformylation comprising the following steps:

a) feeding propane and CO2 to the dehydrogenator reactor to obtain a gas mixture consisting of propane, propylene, syngas, and CO2;
b) feeding the dehydrogenation gas mixture directly to the hydroformylation reactor to produce n-butyraldehyde and i-butyraldehyde;
c) routing the unreactive propane and CO2 back to the dehydrogenation reactor.

2. The process as claimed in claim 1, wherein the Dehydrogenation step is carried out at a temperature between 500? to 600?.

3. The process as claimed in claim 1, wherein the stream from the hydroformylation reactor is fed to the flash distillation unit to obtain butyraldehydes and recover propylene and the catalyst.

4. The process as claimed in claim 1, wherein the stream from the hydroformylation reactor is used to preheat the propane stream which is feedstock to the oxidative dehydrogenation reactor via Heat Exchanger (HE1).

5. The process as claimed in claim 1, wherein the top product from the flash column is recycled back to hydroformylation reactor to reduce the temperature of dehydrogenation gas mixture via Heat Exchanger (HE2).

6. The process as claimed in claim 1, wherein the recovered catalyst and propylene are recycled back to the hydroformylation reactor.

7. The process as claimed in claim 1, wherein the process is a continuous process.

8. The process as claimed in claim 1, wherein the process effectively utilizes refinery grade propylene and syngas without any additional separation.

9. The process as claimed in claim 1, wherein the process minimizes energy consumption and reduces the overall CO2 footprint of the process.

10. The process as claimed in claim 1, wherein the process utilizes CO2 as a mild oxidant to improve the equilibrium of the propane dehydrogenation reaction and simultaneously produce syngas to be used in the subsequent hydroformylation step.