An improved water electrolysis and oxy-fuel combustion coupled tri-reforming process for methanol production and CO2 valorization

Valorization of refinery flue gas through tri‐reforming and direct hydrogenation routes

“…The fuel gas stream, named FUEL in our Aspen flowsheet, depicted in Figure 2A, along with the steam, has been fed to the pre-reformer (PRE-REF). The pre-reformer has been operated at 550 C and 1 atm and modelled via the RGIBBS module [12,15] available in Aspen Plus. This module calculates the thermodynamic properties of a chemical reaction system and predicts the equilibrium state based on the minimization of Gibbs free energy.…”

“…The oxygen stream, O 2 , from ASU, steam from the heat recovery steam generator (HRSG), and a purge stream, PURGE, from the downstream chemical production section have also been routed to REF. The tri-reformer, modelled using RGIBBS [12,29,30] module, has been operated at 850 C and 1 atm so as to obtain the syngas with stoichiometric number (SN) desired for MET and ethanol synthesis. [9] Ni-based catalyst with mixed oxide supports such as Ni/MgO/CeZrO has been considered to be utilized for these reactions, as suggested by Song and Pan.…”

“…[1,[9][10][11] Moreover, the presence of oxygen in the feed stream facilitates the reduction of carbon formation and promotes syngas production while minimizing the formation of unwanted byproducts. [12] However, complete oxidation of methane should be avoided to prevent excessive CO 2 formation (Equation ( 9)), hot spots, and explosive risks in the catalyst bed. Hence, the oxygen flow rate has been optimized to achieve thermoneutrality in the trireformer.…”

“…One of the key advantages of this approach is the highly exothermic nature of the POM reaction, which supplies the necessary energy for the other two endothermic reactions (SMR & DRM). [1,[9][10][11] This enables the possibility of a thermoneutral reactor, [12] thus eliminating the need for external energy requirements and the associated CO 2 footprint. The potential of the tri-reforming process has been demonstrated by Zhang et al, [13] while suggesting it to be an economically feasible method for CO 2 utilization at an industrial scale.…”

“…[15] The pre-reformer converts higher hydrocarbons to methane and enables the use of an impure and less expensive fuel gas stream for valorization purposes. [12] Given that the fuel gas utilized in the above approach (tri-reforming) is derived from fossil fuel, it bears a CO 2 footprint, thereby limiting the amount of CO 2 that can be valorized. Additionally, the energy-intensive air separation unit (ASU) involved in the process also contributes to indirect CO 2 emissions.…”