What is steam reforming reaction?
Steam reforming is the most widespread process for the generation of hydrogen-rich synthesis gas from light carbohydrates. The feed materials natural gas, liquid gas or naphtha are endothermically converted with water steam into synthesis gas in catalytic tube reactors.
What is steam reforming of methane?
In steam-methane reforming, methane reacts with steam under 3–25 bar pressure (1 bar = 14.5 psi) in the presence of a catalyst to produce hydrogen, carbon monoxide, and a relatively small amount of carbon dioxide. Steam reforming is endothermic—that is, heat must be supplied to the process for the reaction to proceed.
What is SMR and ATR?
The difference between SMR and ATR is how heat is provided to activate the endothermic steam reforming reaction. In SMR, the catalyst is contained in tubes that are heated by an external burner. In ATR, a portion of the natural gas is burned to raise the temperature of the process gas before it contacts the catalyst.
What is ATR technology?
ATR is a technology that combines steam reforming and the POX resulting in an overall reaction enthalpy close to zero. The process consists of an initially POX or CPOX zone, which supplies the process heat for the subsequent endothermic steam reforming step.
What is a pox unit?
Partial oxidation (POX) is a type of chemical reaction. It occurs when a substoichiometric fuel-air mixture is partially combusted in a reformer, creating a hydrogen-rich syngas which can then be put to further use, for example in a fuel cell.
Why is steam reforming done at high pressure?
For the steam reforming reaction the production yield of hydrogen kept increasing with pressure because the forward water-gas shift reaction produced additional hydrogen by the reaction of CO with water.
What kind of reaction is steam methane reforming?
Steam-methane reforming is a catalytic process that involves a reaction between natural gas or other low-boiling hydrocarbon derivatives and steam. Steam-methane reforming is the benchmark process that has been employed over a period of several decades for hydrogen production.
What is the efficiency of steam reforming of natural gas?
Steam reforming of natural gas is approximately 65–75% efficient. Production of H2 and CO from hydrocarbon gases (e.g. natural gas) is performed by two well-known “primary” and “secondary” reformers.
Which is the correct equilibrium for steam reforming?
Steam reforming or steam methane reforming is a method for producing syngas (hydrogen and carbon monoxide) by reaction of hydrocarbons with water. Commonly natural gas is the feedstock. The main purpose of this technology is hydrogen production. The reaction is represented by this equilibrium: CH 4 + H 2 O ⇌ CO + 3 H 2
How much methane is produced in the SMR reaction?
The global SMR reaction is endothermic (165 kJ mol − 1), and it yields 4 mol of H 2 and 1 mol of CO 2 for each one of methane (Eqs. 1 and 2). This leads to substantial CO 2 emissions, which are unlikely to be acceptable in a future low-carbon world.