Hydrogen gas is widely used in many industrial applications such as ammonia production and some stages of refining fossil fuels. This article discusses the most common process currently used to produce hydrogen from natural gas; steam reforming method. The method involves four subprocesses. The first subprocess is dehydrosulfurization which purifies natural gas from sulfur contaminants. The second subprocess is steam methane reforming (SMR), which converts natural gas and steam into hydrogen. The third subprocess is the mean temperature shift (MTS) which converts carbon monoxide and vapor into carbon dioxide and hydrogen. The last sub-process is Pressure Swing Adsorption (PSA) which purifies the hydrogen gas produced. The low cost and energy efficiency of the process are one of its main advantages and the reason for its industrial popularity. The disadvantages of the process are the use of non-renewable raw materials and the production of carbon dioxide which is one of the main causes of global warming. Current and future advances in the process include the use of new catalysts to minimize the cost of the entire process and the implementation of carbon capture and storage techniques to reduce the negative environmental impact of the carbon dioxide produced. Keywords: hydrogen gas, steam reforming, dehydrosulfurization, methane steam reforming, mean temperature shift, pressure swing adsorption, carbon capture, carbon storage.1. Introduction The demand for hydrogen is already high and is expected to increase considerably in the coming years due to the growing needs of the refinery industry and new applications such as the production of synthetic fuels or biofuels. In 2004, total global production of hydrogen gas was approximately 50 million meters……middle of paper……e.g., hydrogen sulfide goes through the Claus process to produce elemental sulfur but this process is not described in detail because is beyond the scope of this document.63.2. Steam Meater Reforming (SMR)SMR is the most important sub-process from which the current name of the entire hydrogen gas production process derives. SMR is the reaction that converts purified natural gas and steam into carbon monoxide and hydrogen. The reaction for steam reforming is shown below.5CH_4+ H_2 O →CO+3 H_2 (3)The above reaction is endothermic under standard conditions (∆〖H^o〗_298=206 kJ/mol), which means that the reaction is not thermodynamically favorable and the equilibrium of the reaction is on the side of the reactants. Therefore, the reaction conditions are altered so that the equilibrium constant shifts towards the product side to achieve higher conversion rates.5