Evaluation and analysis of ethylene production using oxidative dehydrogenation
Graphical abstract
Introduction
In industrial processes ethylene is produced from ethane, the second most commonly used natural gas compound in the U.S. each day, over 210,000 barrels of ethane are used, and this number is expected to increase to 380,000 by the end of 2019 [1]. It is used as a building block for different polymers, including polyethylene, styrene and vinyl chloride. Ethane production has increased due to the large amounts of shale gas extraction in the US which was previously unavailable due to technological limitations [[2], [3], [4]].
The industrial practice of ethylene production is achieved through steam cracking, where ethane and steam are heated in the absence of a catalyst and air, to form ethylene along with other multiple products including methane, C3-C5+ hydrocarbons, and acetylene and requires significant investment to separate and purify the ethylene. Alternatively, the oxidative dehydrogenation of ethane is a selective catalytic process operating at much lower temperatures, approximately 300–800 °C, and produces ethylene at approximately 98+% selectivity with only CO and CO2 as by-products. Thus, the separation process for ethane oxidative dehydrogenation is much simpler and significantly less expensive.
Previous work by this group and others on ethane ODH catalysis has reported the effectiveness of a molybdenum, vanadium mixed metal oxide catalyst with either niobium or tantalum oxides in combination with one of following metal oxides: tellurium, antimony, gallium, palladium, tungsten, bismuth or aluminum for the oxidative dehydrogenation of ethane for ethylene production [[5], [6], [7], [8]]. More recent work from this group has reported a novel process for the selective ODH of ethane to ethylene that described the inclusion of an oxygen elimination reactor after the ethane ODH reactor system along with additional units for water removal, CO2 removal, ethylene separation and N2 removal [9]. The process would also allow for the recovery and subsequent reuse of unreacted ethane in the ODH reactor.
More recent work from this group has compared the economic performance of the ethane ODH reaction against the industrially utilized ethane steam pyrolysis reaction using netback analysis for ethylene production cost estimation [1,10]. This work reported that the ethane ODH reaction process would facilitate lower variable cost and decreased fixed cost. Additional system requirements were updated to account for a reduced contingency for the ODH reaction, the recovery of oxygen, improved co-generative recovery of heat, and other energy upgrades within the HYSYS simulated process and these allowances results in lower ethene production costs for ethane ODH over the conventional steam pyrolysis reaction in all categories including the shutdown economics. Additional investigations into proposed improvements in the economics and process safety for the ethane ODH reaction reported that the removal of reaction diluents, nitrogen and steam, the use of membrane separation technology for ethylene separation and the replacement of oxygen by carbon dioxide as an oxidant were observed to improve the ethane ODH reaction economic viability and process safety aspects related to reducing the use of nitrogen in the process and lowering the process temperatures of the ethane ODH reaction compared with ethane steam pyrolysis [11].
Related work has investigated the catalytic oxidation of propane to acrylic acid over the M1 and M2 catalyst systems [12]. It was reported that the family of M1 and M2 catalysts exhibited a surface monolayer with composition unique from the bulk catalyst composition and that the rates of propane consumption and the rates of propene and acrylic acid formation were observed to directly depend upon the vanadium composition in the surface monolayer of the catalyst. Additional ODH-related work has reported the performance of the M1 catalyst for the oxidative conversion of alkanes to alkenes [[13], [14], [15], [16]]. This group has also completed reviews of this ODH catalyst system for process intensification and also for the in-situ / operando techniques for the analysis of oxidation reaction over the M1 catalyst [17,18]. Related work from this group has investigated the use of noble and transition metal-based catalysts for methanol oxidation, higher olefin epoxidation reactions and the non-oxidative dehydrogenation of ethane over Fe-ZSM-5 catalysts [[19], [20], [21], [22]].
Section snippets
Feedstock and product purity
The feedstock for this process contained ethane, air, and methane. Ethane and oxygen, from the air, were the two reactants for the process. Methane and nitrogen were used as inert diluents within the reactor, absorbing heat from the exothermic reaction, and allowing for the reactor to maintain safe operating temperatures. The simulation was based on the feed components being pure, though in standard operational practice this would not be the case. Contaminants such as CO, CO2 and H2O would not
Process simulation analysis
For the determination of which process units were necessary to include in the Dow Fire and Explosion Index (FE&I) safety evaluation; quantity of materials, operating conditions, and specifications of the unit operations were thoroughly analyzed and inspected. FE&I assumes that any unit can handle up to 2268 kg of flammable, combustive or reactive materials [25]. In this analysis, units processing less than 0.454 m3/hr of these aforementioned materials were not taken into consideration for the
Conclusions
A HYSYS simulator was utilized to predict the performance of an ethylene ODH production facility using alternative diluents and separation technology not currently used in the standard industrial process. Ethane was fed along with air into an ODH reactor where it was later mixed with pure methane to cool down the gas. The methane feed was created by its separation from other process gases and was later fed into a recycle stream. This operation of the ODH process was fairly expensive due to the
CRediT authorship contribution statement
Anne M. Gaffney: Conceptualization, Supervision, Investigation, Visualization, Funding acquisition, Writing - review & editing. Jacob W. Sims: Data curation, Formal analysis. Vincent J. Martin: Data curation, Formal analysis. Natalie V. Duprez: Data curation, Formal analysis. Kelsey J. Louthan: Data curation, Formal analysis. Kenneth L. Roberts: Project administration, Resources, Software, Writing - original draft, Investigation, Methodology, Validation.
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgements
The authors would like to recognize the contributions of Sergio Gomez, Abdulaziz Hasanain, Abigale Morgan and Professor Vincent Van Brunt for their work. The direct funding from Compact Membrane Systems, U.S.A. is acknowledged.
References (25)
- et al.
Catal. Today
(2004) - et al.
Appl. Catal. A Gen.
(2001) - et al.
Catal. Today
(2001) - et al.
Catal. Today
(2017) Appl. Catal. A Gen.
(2001)- et al.
J. Catal.
(2001) - et al.
Surf. Sci.
(2017) - et al.
Appl. Catal. B, Environ.
(2019) - et al.
Appl. Therm. Eng.
(2001) Manufacturing USA®. Annual Report
(2016)
New Capacity Will Lengthen US Ethylene Market | Petrochemicals | Platts
US Ethylene Spot Prices Fall to Nine-year Low
Cited by (19)
Enhancement of ethylene production by alkali metal doping of MoVSb mixed oxide catalyst for ethane oxidative dehydrogenation
2023, Applied Catalysis A: GeneralScale-up analysis of the oxidative dehydrogenation of ethane over MoVTeNbO<inf>x</inf> catalysts in an autothermal reactor
2023, Chemical Engineering ScienceNanocomposite catalysts of non-purified MoVNbTeO<inf>x</inf> with CeO<inf>2</inf> or TiO<inf>2</inf> for oxidative dehydrogenation of ethane
2022, Chemical Engineering ScienceCitation Excerpt :Several catalyst systems are being investigated for better performance and lower cost such as NiO, VOx, and Mo-V-(Nb)(Te/Sb)Ox , etc. Among the catalysts for ODHE process (Al-Ghamdi et al., 2013; Argyle et al., 2002; Chen et al., 2015; Chu et al., 2016; Chu et al., 2015a; Concepción et al., 2011; Dang et al., 2018; Gaffney et al., 2021; Ishchenko et al., 2016; Park et al., 2018; Ramesh et al., 2014; Wu et al., 2012; Xie et al., 2005; Yun et al., 2018; Zhang et al., 2019; Zhou et al., 2019; Zhu et al., 2012), MoVNbTeOx composite oxide catalyst shows the best potential for its catalyst performance at relatively low operating temperature at 400 °C or so (Cavani et al., 2007; Valente et al., 2014). However, the implementation of the ODHE process based on MoVNbTeOx is still limited by the low catalytic performance of the catalyst, which can only compete with conventional processes if several requirements are satisfied simultaneously (i.e. yield of C2H6 ∼ 60%, ethylene productivity > 1.0 kgC2H4/kgcat/h, long-term stability, etc) (Cavani et al., 2007).