Non-catalytic plasma-arc reforming process of methane with carbon dioxide for hydrogen production

Abstract

The world revolves around energy; it is needed to power industry, move people and products around the world and provide safety and convertibility for everyone. Current technologies produce huge amounts of greenhouse gases. New technologies are needed to produce cleaner energies and save on valuable fossil fuel. This research project evaluates the Non-catalytic Plasma-arc Reforming Process for the production of synthesis and hydrogen gas. Carbon dioxide was used as the oxidizing agent instead of steam that is normally used in the Steam Methane Reforming Process. The Plasma-arc Reforming Unit operates at very high temperatures (2 000-5 000°C) and this enables the reforming reaction to occur stoichiometrically in the unit. A 500 MWt Pebble Bed Modular Reactor can supply 21x8 MW Plasma-arc Reforming Units with electrical power. Synthesis gas can be produced with a hydrogen-to-carbon monoxide ration of 1:1, which can be varied between 1:1 and 3:1, by adding steam to the inlet gas stream. The variation in the ratio can be achieved by changing the steam to carbon dioxide feed ratio. A total of 1 435 million Nm3 synthesis gas can be produced annually at a production cost of $10.43 per GJ. The hydrogen production by the Plasma-arc Reforming Process can be increased by making use of the water-gas-shift reaction. Hydrogen can be produced with a purity of 99.0% using a Pressure Swing Absorption system, in order to separate the hydrogen from the product gas stream. The annual production of hydrogen is 1 120 million Nm3 at a production cost of $14.17 per GJ. A sensitivity evaluation was conducted on the process used for the production of synthesis and hydrogen gas. It was observed that natural gas and electrical costs have a significant impact on the production cost and profitability of the plants. The Steam Methane Reforming Process was also compared with the Non-catalytic Plasma-arc Reforming Process, from which it was concluded that Plasma-arc Reforming competes well with Steam Methane Reforming.