(433a) Technical, Economic and Environmental Viability of Offshore CO2 Reuse from Natural Gas By Dry Reforming

The recent discoveries of Pre-Salt layers in Brazil require process developments for enhanced sustainability as these reservoirs have oil with associated natural gas exhibiting an expressive amount of CO2 (FORMIGLI, 2007;GAFFNEY, 2010). The challenge is thus to expand the supply of this fossil raw material to produce energy and chemicals in a carbon-constrained economy. In this scenario, CO2 capture and reuse techniques are important routes for a moderate transition from the present fossil-based economy to a long-term sustainable future. This work evaluates two process alternatives for a floating unit consisting of physical absorption of CO2 from natural gas, with propylene carbonate, producing a natural gas stream poor in CO2 and a stream consisting of a mixture of CO2 and hydrocarbons. The two alternatives are evaluated for processing the CO2 rich stream to yield methanol. Technical, economic and environmental analyses of the process flowsheets are performed for comparison purposes. Alternative 1 combines dry and steam reforming in one reactor (one pot reactor), while Alternative 2 segregates the two reactions: dry reforming occurs in one reactor and water gas-shift reaction takes place in a subsequent reactor. The two Alternatives are evaluated with Aspen HYSYS® simulator for calculation of energy and mass balances necessary to assess economic and environment performances. The economic evaluation employed Capital Cost Estimation Software (CAPCOST) for calculations of CAPEX and OPEX, and the Waste Reduction Algorithm Software (WAR) was used to evaluate the potential environmental impacts. Results indicate the Bi-Reforming process (Alternative 1) as feasible according to all investigated aspects, with a methanol production of 17960 kg/h, 4 times higher compared to the Dry-Reforming alternative. For Alternative 1, the CAPEX was estimated as U$$75.497.127, the OPEX as U$$122,575,216, and the Sales Revenue as U$$144,890,686. Regarding environmental impacts, the index PEI/hour for Bi-Reforming was 868 PEI/hr.