*2.1. Blue Hydrogen*

The main industrial technology for hydrogen production is steam methane reforming (SMR) [13,14]. The autothermal reforming (ATR) is the most common production method [14–19]. Also popular is dry reforming of methane (DRM), partial oxidation (POX) and their combinations.

In recent years, the technology of production and purification of synthesis gas has attracted much attention from both researchers and industry [19]. Since its development, it has become one of the main directions for more efficient, sustainable and environmentally safe use of hydrocarbon resources.

The reference [17] presents the topic of hydrogen-based fuel cells and energy, and addresses important trends in the contemporary energy industry, in particular, how to integrate fuel reprocessing into modern systems.

According to [16], it is important to remember that the route of hydrogen production and the choice of a specific technology depends on the type of energy and available raw materials, as well as on the required purity of the final product.

POX technologies were originally proposed by Texaco and Shell [17,18]. They are widely used in industry, and at present there are over 300 operating installations [11].

In Russia, many research centers have carried out theoretical and experimental investigations of the process of hydrocarbon partial oxidation [18,20]. However, there are no industrial POX installations. The source [20] describes in detail a method for producing synthesis gas for low-tonnage methanol production based on partial oxidation of natural gas in original three-component (hydrocarbon feedstock—oxidizer—water) synthesis gas generators (SGG) (hydrogen, carbon monoxide and carbon dioxide, water steam and ballast gases).

To carry out POX, it is possible to use chemical reactors based on power plants with high productivity and relatively low energy consumption for conversion and small weight and size characteristics. It favorably distinguishes them from any other partial oxidation devices [18,20,21]. The source [21] considers the physical model and the design of the SGG. A method for calculating the nominal geometric dimensions of the SGG is proposed, which makes it possible to assess the mass and size characteristics of the SGG already at the stage of implementation of the basic project.

The recent research [22] found that in the case of synthesis gas production by POX of natural or associated petroleum gas, the estimated cost of hydrogen production is 1.33 euros/kg H2. The cost of large-scale production of H2 varies from 1 to 1.5 euro/kg H2. It is worth remembering that the decision on the economic feasibility of using natural or associated petroleum gases for the production of H2 should be made in the context of transport infrastructure or the use of hydrogen directly at the site of oil or gas production.
