Techno-economical analysis of a modular chemical looping plant for the dehydroaromatization of methane in stranded natural gas
Date
2019
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Abstract
A modular chemical looping plant is proposed for the dehydroaromatization of methane in stranded natural gas to liquid hydrocarbons, which are more easily transportable. The purpose of this thesis is to asses the economic viability of this process compared to flaring of stranded natural gas. ☐ Four plants have been designed in this thesis: two with and two without hydrogen production. The plants with hydrogen production do not have to out compete flaring, instead their goal is to reach a production cost target of $2 per kg of hydrogen produced. Both the plants with and without hydrogen production have designs aimed at separating the produced benzene/naphthalene mixture into its constituents, to sell the higher priced benzene independently of the naphthalene, and designs that do not separate this mixture, instead selling it as virgin naphtha. All plants have been designed for 50 MSCFD and 175 MSCFD methane feed rates. ☐ The pioneer plants without hydrogen production are not economically viable, as their net present values are always smaller than those of flaring installations. The hydrogen producing pioneer plants also prove incapable of producing hydrogen at sufficiently low costs, mainly due to their high capital costs and low capacities. Using experience learning curves to simulate the cost reducing effects of mass production, the cost of the final, mass-produced plants is estimated. Under the current market conditions, these final plants still prove incapable of replacing flaring, but the final plants with a methane capacity of 175 MSCFD can produce hydrogen below the 2 $/kg cost target. In 2008 and 2013, benzene and naphtha prices were sufficiently high to ensure the economic viability of the final plants with a methane capacity of 175 MSCFD. Under these conditions, their net present value is greater than that of flaring installations and the cost of hydrogen production dips below 0 $/kg, due to increased benzene and naphtha revenues.