Steam methane reforming SMR

However, many reactions of commercial interest have chemistry, mechanical, or system requirements that preclude the use of cross-flow reactors. Processes cannot use a cross-flow orientation primarily because of high temperatures and the need to internally recuperate heat such as steam methane reforming (SMR) [12, 13] and oxidation reactions [14]. Counter- and coflow devices require a micromanifold to dehver sufficiently uniform flow to each of the many parallel channels. 

The analysis showed, with various "value adders" (e.g., oxygen sales and carbon-emission-offset credits), the cost of wind-source gaseous hydrogen delivered by pipelines from production point to distant markets (about 200-1000 mi.) at an untaxed wholesale energy unit cost will be competitive with market prices (in 2005) of gasoline and hydrogen fuel made from natural gas by steam methane reforms (SMRs). 

For the first decades, all roadmaps show a focus on fossil-based hydrogen production options, mainly onsite and decentral steam methane reformers (SMR), electro-lysers and hydrogen as a by-product from the chemical industry. In some regions, hydrogen is also produced to a certain extend by nuclear, electrolysis, biomass and waste gasification. Later on, with a significant increase of hydrogen, the production... 

Steam methane reforming (SMR) is the most widely practiced commercial process for the production of syngas and hydrogen almost 50% of the world s hydrogen production comes from natural gas. Two equilibrium reactions, steam reforming and the water-gas shift (WGS) reaction, are at the heart of the hydrogen production process ... 

Equations (5.46) and (5.47) are referred to as steam methane reforming (SMR) reaction and Water Gas Shift (WGS) reaction respectively. These reactions are homogenous reactions that occur everywhere inside the anode, whereas Equations (5.48) and (5.49) only occur at the active triple phase boundary. Treatment of source terms due to electrochemical oxidation of H2 (Equation 5.49) is already covered in the previous sections and the treatment is similar for electrochemical oxidation of CO (Equation 5.48). Specie source terms due to homogenous reactions in the mechanism are given by ... 

Natural gas (methane, or ch ) is by far the most common source of hydrogen.10 Steam methane reforming (smr) generates about... 

The ATR (Autothermal Reforming) process makes CO-enriched syngas. It combines partial oxidation with adiabatic steam-reforming and is a cost-effective option when oxygen or enriched air is available. It was developed in the late 1950 s for ammonia and methanol synthesis, and then further developed in the 1990 s by Haldor Topspe2. The difference between Steam Methane Reforming (SMR) and ATR is in 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. 

The reaction between methane (or other hydrocarbons) and steam to syngas is endothermic and requires high temperatures. In addition, it competes with other reactions. Table 5.4.1 lists the important reactions that play a role. Indeed, only at temperatures above 700°C does the steam methane reforming (SMR) become thermodynamically favored over the water-gas shift (WGS) and the carbon formation reactions in Table 5.4.1. 

Worldwide production of hydrogen is about 41 million tons per year (ORNL, 2003). Since over 80 percent of this production is accomplished by steam methane reforming (SMR), this method is discussed first. 

Methane reacts with steam in the presence of a supported nickel catalyst to produce a mixture of CO and H2, also known as synthesis gas or syngas as represented by Equation 2.1. This reaction is also referred to as steam methane reforming (SMR) and is a widely practiced technology for industrial production of H2. However, the SMR is not really just one reaction as indicated in Equation 2.1 but involves contributions from several different catalyzed reactions such as water-gas shift... 

Table 2.3. Thermodynamic Data for the Steam Methane Reforming (SMR) Reaction...

Figure 10.1. Conventional steam methane reforming (SMR) route for hydrogen production.

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