Comprehensive assessment of solar cracking of natural gas for the production and transportation of turquoise energy carriers

Abstract

Bridge technologies incorporating integrated energy production systems are used to adapt to the growing global energy demand while reducing greenhouse gas emissions. This study aims to propose a system to produce energy in the form of turquoise hydrogen, ammonia, and urea from natural gas. In this study, natural gas is fed to a fluidized bed reactor where high temperatures crack the light-end hydrocarbons into hydrogen and solid carbon. The hydrogen is split between the stored final product and the remainder is further processed as an intermediate product to produce ammonia and urea. This integrated process uses a zero-emission thermochemical cracking unit utilizing solar power as the primary heat source. This work analyzes the feasibility of transporting the produced energy carrier fuels; turquoise hydrogen, ammonia, and urea, overseas for fuel cell power production. The processes are modelled using Aspen Plus© and Engineering Equation Solver software. The main system feed is 4969 kg/h of natural gas, 3733 kg/h nitrogen, and 1991 kg/h of oxygen producing 397 kg/h of hydrogen, 2136 kg/h of ammonia and 4752 kg/h of urea. An integrated Rankine cycle generates 957 kW of power in a steam turbine from waste heat. The supply chain's boil-off gas rates are 1% and 0.02% for hydrogen and ammonia, respectively. The total electrical energy output of the energy carriers used in the fuel cells is 185,900 MWh from hydrogen, 362,100 MWh from ammonia and 458,700 MWh from the urea fuel.