Hydrogen Production From Biogas Reforming: An Overview of Steam Reforming, Dry Reforming, Dual Reforming, and Tri-Reforming of Methane

Abstract

Nowadays, around 96% of hydrogen is produced from fossil resources, and particularly from natural gas, oil and derivatives, and coal. Chemicals synthesized from these fossil resources are usually obtained via synthetic gas, which is produced by steam reforming of natural gas. Details about steam reforming will be discussed later. Scheme 4.1 below illustrates the most common products that can be obtained from syngas, including hydrogen, methanol, liquid fuels, synthetic natural gas (SNG), ammonia, and heat and power.Hydrogen from water electrolysis accounts only for about 4% of total hydrogen production. Naturally, water electrolysis using electricity from renewable resources, such as solar, wind, or hydro is a promising way for green hydrogen production. However, the process still needs to be improved in order to reach the competitive cost required by the hydrogen market.Another way to produce green hydrogen is the valorization of bioresources, such as biogas. This last one is obtained from biomass, residues, or wastes by anaerobic digestion. In general, two types of biogas are distinguished:(1) digested gas from anaerobic digester, which is commonly called biogas, and (2) landfill gas from landfill sites (IEA, 2009). The production of hydrogen from biogas and landfill gas can be achieved via a syngas route as shown in Scheme 4.2 below. Syngas is obtained from biogas or landfill gas by different reforming processes, which will be detailed later. Then a mixture of H 2 and CO 2 can be obtained from syngas by the watergas-shift (WGS) reaction. Finally, hydrogen can be separated from the mixture with CO 2 by using a pressure swing adsorption (PSA) or an equivalent process.Both biogas/landfill gas reforming and WGS are catalytic processes. The reforming step can be achieved with catalytic steam reforming process, which is already commercialized for natural gas. However, the energy balance of the steam reforming is not optimized because of a large excess of water vapor, which is required with current catalysts. Because the composition of Natural gas Oil and derivatives Charcoal Stem reforming Syngas •Hydrogen •Methanol •Liquid fuels by Fisher-Tropsch •Synthetic natural gas •Ammonia •Heat and power •Energy in chemical looping SCHEME 4.1 Chemicals and energy from fossil resources via steam reforming. Biomass Residus Wastes Bio-degradation Biogas Landfill gas Reforming Syngas WGSR H 2 , CO 2 H 2 PSASCHEME 4.2 Main steps for the production of hydrogen from biogas or landfill gas via syngas route. Adapted from IEA, 2009. IEA bioenergy, Task 37-Energy from biogas and landfill gas.(4.1) Dry reforming of methane (DRM); (4.2) Boudouard reaction; (4.3) water-gas-shift (WGS) reaction; (4.4) methane cracking; (4.5) steam reforming of methane; (4.6) steam reforming of carbon; (4.7) partial oxidation of methane; (4.8) methane combustion; (4.9) partial oxidation of carbon; (4.10) carbon combustion; and (4.11) Methane reforming with large excess of steam. All molecules are in the gas state except carbon (C), which is in the solid state.

Structured silicalite‐1 encapsulated Ni catalyst supported on SiC foam for dry reforming of methane

“…Similar scenario was also expected in the conventional Ni/S1‐SiC catalyst. As compared with the state‐of‐the‐art DRM Ni catalysts under comparable conditions, 50 the H 2 /CO ratio achieved by the Ni/S1 in this work was comparatively low. This is possible since these Ni catalysts are mostly supported on alumina, which is less porous than zeolites, accordingly, the support Ni phases might be readily accessible to reactants and coking could be reduced.…”

Review on the catalytic tri-reforming of methane - Part I: Impact of operating conditions, catalyst deactivation and regeneration

“…On the other hand, the increase of the pressure disfavors TRM reaction. However, reforming reactors typically operate at high pressures (3-20 bar) to decrease reactor size and to meet the high pressure needs of downstream applications of syngas [17]. H 2 and CO are formed as the two main products and their formation is strongly favored at high temperature.…”

“…The increase of CO 2 or H 2 O contents in the feed composition is favorable for methane conversion, and limits solid carbon formation [16][17][18][19]. For example, by keeping unchanged the initial amounts of CH 4 , CO 2 and O 2 at 2.0, 1.0 and 0.1 mol, respectively, the increase of the initial amount of H 2 O from 0.8 to 1.0 mol allows lowering the temperature for complete CH 4 conversion from 1000 to 900 • C, and the temperature for the nearly-complete suppression of solid carbon from 1000 to less than 850 • C. In parallel, the molar ratio of H 2 /CO increases from ca.…”

PrFeO3 Photocathodes Prepared Through Spray Pyrolysis

“…Hydrogen can be burnt as a fuel or oxidized in fuel cells to generate electricity, producing just water as a by‐product . Currently, most of the production of hydrogen relies on methane steam reforming which readily emits CO 2 into the atmosphere . Photoelectrochemical (PEC) water‐splitting is considered as an alternative route for sustainable hydrogen production.…”