Deterministic and stochastic economic analysis based on historical natural gas and CO 2 allowance prices for steam reforming of methanol

Abstract

As an appropriate hydrogen supply system for high temperature polymer electrolyte membrane fuel cells, steam reforming of methanol (SRM)is proposed because reformate gas including low quality H 2 with some impurities can be directly used as the fuel. In this study, we compare two SRM systems with and without the use of tail gas from pressure swing adsorption and comprehensive economic analysis is performed for the SRM process with the use of tail gas to estimate a unit H 2 production cost (C UHP )based on historical data of natural gas and the CO 2 allowance prices for Korea, Europe, Western Climate Initiative (WCI), and Regional Greenhouse Gas Initiative (RGGI). From deterministic economic analysis with a H 2 production capacity of 700 m 3 h −1 , the C UHP values are 6.88 $ kgH 2 −1 for Korea, 6.84 $ kgH 2 −1 for Europe, 6.50 $ kgH 2 −1 for WCI, and 6.54 $ kgH 2 −1 for RGGI, respectively. Furthermore, additional two scenarios, pessimistic and optimistic ones (Scenario 1 and 2, respectively), are investigated to evaluate the current level of C UHP values for H 2 production capacities from 30 to 700 m 3 h −1 . With a Monte-Carlo simulation method, stochastic economic analysis is carried out to predict the ranges of potential C UHP values for each region. The C UHP values for WCI and RGGI show the narrow distributions meaning lower change of C UHP ; however, a wide range of distribution for Korea and Europe suggest that there is considerably higher variation, demonstrating the necessity of stochastic uncertainty analysis when assessing the economic feasibility.