What is steam reforming reaction?

Steam reforming is an exothermic reaction that is carried out by passing a preheated mixture comprising methane (sometimes substituted by natural gas having high methane content) and steam through catalyst filled tubes. The products of the process are a mixture of hydrogen, carbon monoxide, and carbon dioxide.

What is steam to carbon ratio in reformer?

The steam to carbon ratio is the ratio of moles of steam to moles of carbon in the reformer feed. It is obtained by dividing the molar flow rates of steam and feed. The reformer feed must contain sufficient steam to avoid thermal cracking of the hydrocarbons and coke formation.

How much hydrogen is produced from steam reforming?

Steam reforming of natural gas is 65–75% efficient. The United States produces 9–10 million tons of hydrogen per year, mostly with steam reforming of natural gas. The worldwide ammonia production, using hydrogen derived from steam reforming, was 144 million tonnes in 2018.

How much CO2 is produced from steam methane reforming?

The Carbon Footprint of Steam Methane Reforming In the process of producing one molecule of CO2, four molecules of hydrogen (H2) are produced, with the steam contributing the additional hydrogen. Thus, per 1 million standard cubic feet (SCF) of hydrogen produced from methane, 250,000 SCF of CO2 will be produced.

How much hydrogen is produced in SMR?

Overall, about 1.392 mmbtu NG is needed to produce 1 mmbtu H2 (in LHV). This leads to SMR onsite CO2 emissions of about 9.4 kg/kg H2, or 82,658 gCO2/mmbtu H2, or 78.3 g CO2/MJ H2, in LHV, which is close to the median CO2 from the GHGRP as reported above.

How much co2 is produced from steam methane reforming?

What is the oxygen excess ratio for steam reforming reactions?

High excess of steam is required, expressed by the (molar) steam-to-carbon (S/C) ratio. Typical S/C ratio values lie within the range 2.5:1 – 3:1.