Modular‐scale ethane to liquids via chemical looping oxidative dehydrogenation: Redox catalyst performance and process analysis

Abstract

The difficulties in the liquefaction and transportation of ethane in shale gas has led to significant rejection, via reinjection or flaring, of this valuable hydrocarbon resource. Upgrading this low-value, isolated ethane into easily transportable liquid fuels is a promising solution to this supply glut. In this study, we present a modular system that can potentially be operated economically at geographically isolated gas-processing facilities. The modular ethane-to-liquids (M-ETL) system uses a chemical looping-oxidative dehydrogenation (CL-ODH) technology to efficiently convert ethane and natural gas liquids into olefins (primarily ethylene) via cyclic redox reactions of highly effective redox catalyst particles. The resulting olefins are then converted to gasoline and mid-distillate products via oligomerization. CL-ODH eliminates air separation and equilibrium limitations for olefin generation. It also simplifies the process scheme and reduces energy consumption. Here, we present experimental proof-of-concept data on CL-ODH conversion of ethane to ethylene. Using the CL-ODH performance data at 750 C, we show that a simple, single-pass configuration can be economically viable at distributed sites. We identify that economic factors such as the capital cost, price of ethane feed, and value of electricity byproduct have strong effects on the required selling price of the liquids. It is also noted that the economic viability of the M-ETL system is relatively insensitive to the liquid yield under a low ethane price scenario. The demand and value of electricity at distributed locations, on the other hand, can play an important role in the optimal process configuration and economics. K E Y W O R D Sethane, fuel, gas-to-liquids, natural gas liquids, oxidative dehydrogenation, shale gas

Chemical looping beyond combustion – a perspective

“…113 The significant process intensification of CL-ODH is enabled by: (i) built-in air separation via chemical looping; (ii) higher ethane conversion with autothermal operations via the in situ oxidation of hydrogen; and (iii) simplified downstream product separation due to the higher ethylene yield and the combustion of hydrogen. 256 We note that extensive research has been conducted for catalytic ethane ODH in the presence of gaseous oxygen, [257][258][259][260] but with limited success, 261,262 The key challenges for catalytic ODH resides in the cost of oxygen, safety issues related to the oxygen/ethane co-feed, the lack of catalysts with high activity and selectivity, and the complexity for the removal of oxygenate byproducts. To date, no suitable ODH catalysts have been identified to achieve sufficiently high olefin yields (B70%) such that ODH could replace the commercial steam cracking processes.…”

Recent Advances in Intensified Ethylene Production—A Review

“…Considering that a typical new shale oil well produces 1500 MCF per day of natural gas, distributed C 1 and/or C 2 conversion technologies at comparable scales can create significant opportunities for emission reduction and value creation. Although converting C 1 /C 2 into ethylene would not address the transportation issues at distributed shale gas production sites, ethylene and other light olefins can be liquefied via oligomerization, as demonstrated by ARCO and Mobil, among others. − The selectivity and yields of olefin oligomerization can be significantly higher than those of Fischer–Tropsch synthesis. Therefore, gas liquefaction routes through light olefins may be advantageous in comparison to the synthesis gas route at distributed scales.…”

A molten carbonate shell modified perovskite redox catalyst for anaerobic oxidative dehydrogenation of ethane

“…In route 2, CL-ODH is conducted at temperatures substantially lower than thermal cracking temperatures (≤700°C) via surface activation of ethane in the presence of active oxygen species supplied by the redox catalyst. The lowered operating temperature makes it more suitable for CL-ODH in a modular packed bed for distributed ethane conversion (16). In terms of route 2 redox catalysts, V-and Mo-based oxides, which are commonly used for conventional ODH with oxygen co-feed, have been investigated (17)(18)(19)(20).…”