Techno-economic and exergy analysis of polygeneration plant for power and DME production with the integration of chemical looping CO2/H2O splitting

Abstract

In the present study we propose a novel gas feed polygeneration process for the dimethyl ether (DME) and power production and carbon capture (CCS). The process consists of chemical looping CO2/H2O dissociation (CL) unit to produce syngas (CO and H2 with methane reduction step in redox cycle) from exhaust gases for DME production in a packed bed reactor. Except for the chemical looping CO2/H2O dissociation unit (consist of two interconnected reactors) which is under development stage, the process is considered based on already existing industrial components. The aim of the present work is to assess the process based on energy efficiency and the economic performance of the integrated chemical looping unit for industrial scale DME production plant. It was found that the price of the DME produced was 34 $/GJ (DME LHV). The beneficial integration proposed resulted in a production of 103 MWe and 2.14 kg/s of DME with an energy and exergetic efficiency of about 50% and 44%, respectively. A discounted cash flow analysis was performed to evaluate the profitability of the process. In order to have a positive NPV, a selling price of electricity and DME higher than the current market was required. Finally, an exergo-economic analysis was executed to detect which are the main causes of the low economic performance. An exergo economic factor of 0.37 of the overall plant was found, suggesting that an improvement in the efficiency of the equipment is needed. The potential of CO2/H2O dissociation unleashes in liquid hydrocarbon and fuel production strategies, which are hindered by only-thermal reduction step in the existing approach for solar thermochemical syngas production. The analysis also provides information on the main economic drives associated with high capital investment in the process plant with individual sub-systems. The energy, exergy and economic analysis have proved to show the scope of improvements over the conventional method of manufacturing DME considered 100% carbon capture. The analysis also reflects the strong potential of chemical looping syngas production pathways to integrate with polygeneration system to increase the overall efficiency with reduced cost of carbon capture. The baseline simulation of the polygeneration plant proposes a methodology for assessment of the impact on the overall efficiency, economic performance and water for advances system designs.

Power-to-liquidviasynthesis of methanol, DME or Fischer–Tropsch-fuels: a review

“…336 In particular, an economic comparison of the different process routes from CO 2 described in Section 3.2.1 within the PtL context is missing. Several authors have investigated the production of DME from biomass, estimating the manufacturing cost in a range of 302-891 h per t. [337][338][339] Further, CCU concepts based on coal gasification and natural gas reforming using the direct and View Article Online two-stage process route have been analysed, [340][341][342] indicating cost advantages for the two-stage process route due to the simplified product upgrade. 342 Due to the different boundary conditions and plant concepts (e.g.…”

Intensification of Catalytic Processes through the Pellet Structuring: Steady-State Properties of a Bifunctional Catalyst Pellet Applied to Generic Chemical Reactions and the Direct Synthesis of DME

“…A classical strategy based on a finite difference method was used to discretize the pellet model, both in the case of the system of two elementary reversible chemical reactions and the direct synthesis of DME from syngas. Second-order differential Equations (20)- (22) with boundary conditions (Equations (25) and (26)) were transformed into a system of 3N nonlinear algebraic equations by approximation of the derivatives in N = 51 nodes, equally spaced along the particle radius, using central difference schemes [38]:…”

“…Due to the very high importance of this technological process, in the last two decades different preparation methods of bifunctional catalyst pellets for DME synthesis were investigated [4,19,20]. Moreover, the integrated and polygeneration systems based on the direct synthesis of DME were proposed and analyzed in terms of the process performance and economical aspects [21,22]. Nevertheless, while the choice of the chemical species of the catalysts and the preparation methods have been analyzed thoroughly, only recently the spatial distribution of different types of catalytic active centers have started to be explored as an additional design parameter [23].…”

Reversible Solid Oxide Cell (ReSOC) as flexible polygeneration plant integrated with CO2 capture and reuse

“…The electrolytic H2 supplied by the storage ensures that the RWGS reaction (CO2 + H2 → CO + H2O) yields a syngas with a H2/CO ratio around 0.95. This condition maximizes the DME synthesis [8], occurring in a catalytic plug-flow reactor at 50 bar and 200 °C. The high fraction of DME in the product stream reduces the heat duty for the downstream cleaning process (CO2 separation, distillation of DME from residual H2O/MeOH mixture) yielding a >99.99%v DME stream for automotive application.…”