Comprehensive Assessment of Solar Cracking of Natural Gas for the Production and Transportation of Energy Carriers

To adapt to the growing global energy demand while reducing emissions, bridge technologies incorporating integrated energy production systems are used. Due to its high energy content, clean hydrogen production from natural gas is a plausible transition route towards renewable fuels and minimizing the environmental impact of fossil fuels. This research aims to propose a system to produce energy in the form of turquoise hydrogen, turquoise 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; it 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/hour of natural gas, 3733 kg/hour of nitrogen, and 1991 kg/hour of oxygen, producing 397 kg/hour of hydrogen, 2136 kg/hour of ammonia, and 4752 kg/hour 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 (BOG) rates during overseas transport are 1% and 0.02% for hydrogen and ammonia, respectively. Only heel mass losses are considered for urea as this energy carrier is transported in solid form and dissolved in a 30% weight-by-weight (w/w) aqueous solution for use in fuel cells at the demand region. The total electrical energy output of the energy carriers used in the fuel cells was 185,900 MWh from hydrogen, 362,100 MWh from ammonia and 458,700 MWh from urea fuel.