01/08/2023
Hydrogen production from natural gas reforming principle and cost influencing factors
Natural gas reforming is one of the most common commercially available hydrogen production processes, which utilises the methane (CH4) in natural gas to produce hydrogen (H2) and carbon dioxide (CO2) in a chemical reaction. The process consists of two main steps: steam reforming and water-gas conversion.
1. Steam Methane Reforming (SMR):
Steam reforming is the most commonly used method of hydrogen production and the basic reaction is as follows:
CH4 + H2O → CO + 3H2
Methane reacts with water vapour in the presence of a catalyst to produce carbon monoxide and hydrogen. Subsequently, carbon monoxide reacts further to produce carbon dioxide and more hydrogen.
The steam reforming process has the following main features:
Catalyst: The reaction needs to take place at a high temperature (around 700-1000°C) and in the presence of a catalyst, commonly used catalysts include nickel and rhodium.
Carbon dioxide production: One of the main disadvantages of steam reforming is the production of large amounts of carbon dioxide, which has led to the production of hydrogen known as "grey hydrogen", as its production is closely linked to carbon emissions.
2. Water Gas Shift (WGS):
Water Gas Shift (WGS) is a reaction used to reduce the carbon monoxide content of the steam reforming process, thereby increasing the hydrogen yield:
CO + H2O → CO2 + H2
In WGS, carbon monoxide reacts with water vapour to form carbon dioxide and additional hydrogen. This process can reduce the carbon monoxide content to a very low level, thus reducing the production of grey hydrogen.
Cost Assessment:
The cost of natural gas reforming for hydrogen production is affected by several factors, including natural gas price, catalyst cost, energy cost, facility size, and the cost of handling CO2 emissions.
Natural gas price: Natural gas is the main feedstock for hydrogen production, and its price fluctuations will have a direct impact on the cost of hydrogen production.
Energy costs: Steam reforming and water-to-gas conversion processes require large amounts of energy supply, and energy costs play a key role in the cost of hydrogen production.
Catalyst costs: Catalysts are used to accelerate the reaction, and their cost will also have an impact on the cost of hydrogen production.
Carbon dioxide emissions treatment costs: As the steam reforming process produces carbon dioxide, treating or capturing these emissions can also add to the cost of hydrogen production.
Overall, hydrogen production from natural gas reforming is the most mature commercially available process for hydrogen production, and its cost of hydrogen production is typically relatively low, but it also faces issues such as environmental impact and carbon emissions. As the hydrogen economy grows, the search for more environmentally friendly and low-carbon hydrogen production technologies will become an important direction in the future.
