A Techno-Economic Study of Catalytic Decarboxylation Process for Naphthenic Acids Utilizing Protonic Zeolite Socony Mobil Type 5 (HZSM-5) Catalyst

Abstract

This paper represents a detailed techno-economic analysis of a typical commercial-scale catalytic decarboxylation process of naphthenic acids over HZSM-5 zeolite. Simulation of the process has been performed in ASPEN Plus®. The performance of the modeled unit was compared to experimental results data from a similar plant. Two models were developed for the proposed industrial plant based on continuous flow reactors; the first is based on a fluidized bed reactor, and it was modeled as a continuous stirred tank reactor (CSTR) unit, and the second is a semi-regenerative process that consists of three fixed-bed reactors with intermediate preheaters and are modeled as three plug flow reactors (PFR). The outcome of the economic analysis of the two proposed commercial scale reactors of a decarboxylation process of a capacity of 11,000 bbl/day showed that the CAPEX, including the total equipment cost for the fluidized bed reactor plant and semi-regenerative process plant, was $44,319,362 and $4,447,919, respectively. The annual operating cost for the fluidized bed plant and semi-regenerative process plant is 45,269,180 $/year and 1,771,839 $/year, respectively. Our results demonstrated that catalytic decarboxylation over HZSM-5 zeolite is economically feasible using a semi-regenerative process, and is a promising method for removing naphthenic acid. The insight obtained from this work can be used as a basis for more comprehensive future financial and risk modeling of the process. The cost estimated in this work was compared to the Khartoum refinery cost for the naphthenic acid corrosion mitigation system, with a saving of $29,459,528.