Optimizing Hydrocarbon Steam Conversion Hydrogen Generation Process to Reduce Hydrogen Production Costs

In recent years, with the increasing demand for fuel cleanliness due to environmental regulations and the increase in the processing volume of low-quality crude oil, the demand for hydrogen from refineries has also increased significantly. The large-scale hydrogen production methods in the industry include steam conversion and partial oxidation. At present, the steam reforming hydrogen production process dominates in hydrogen production plants. Hydrogen costs represent a large proportion of the total hydrogenation costs of refineries. Therefore, how to select appropriate process conditions to reduce hydrogen production costs has become a primary consideration for hydrogen production plants.
Hydrocarbon steam reforming process is divided into two stages of transformation and transformation. The hydrocarbon conversion process is carried out in a temperature range of 500 to 850°C in a tube-type variable temperature catalyst bed, and the hydrocarbon and water vapor react to produce carbon monoxide and hydrogen. The carbon monoxide in the reformed gas reacts with the steam under the action of the catalyst and is further converted to hydrogen and carbon dioxide. Typically 87% of the hydrogen is produced by the conversion process and the remaining 13% of the hydrogen is produced by a conversion process.
Hydrogen production process conditions have a great influence on hydrogen production costs: (1) reformer inlet temperature: increasing temperature can reduce raw material and fuel consumption; (2) reformer outlet temperature: increasing outlet temperature can increase conversion rate and reduce raw materials Consumption; (3) Water to carbon ratio: reducing water to carbon ratio can reduce fuel consumption; (4) reformer operating pressure: appropriate reduction in pressure favors shifting of reaction equilibrium toward hydrogen production; (5) Use of pre-reforming process Improvements in conversion catalysts can increase plant capacity and increase production.
In recent years, with the application of new high-temperature conversion furnace tubes and the development of high performance hydrogen production catalysts, the process conditions of hydrogen production plants can be optimized within a wider range. At present, the technological conditions for the reformer design of domestic hydrogen production plants are significantly improved compared to the early 1990s: the inlet temperature of the reformer can be increased from 480 to 500°C to 540 to 580°C, and the outlet temperature of the reformer can be increased from 780 to 800°C to 840°C. At ~850°C, the ratio of water to carbon dropped from 4 to 5 to 3.2 to 3.5, and a pre-conversion process using domestic catalysts has been adopted in engineering practice.
Improvements have also been made in the conversion process optimization. With the increase of the low-temperature activity of the shift catalyst, the inlet temperature of the medium-temperature reactor is currently reduced from 360°C to 340°C. In addition, on the basis of the commonly used mid-temperature conversion process, there are also processes for increasing the low-temperature conversion and isothermal conversion.
The oil refining industry is facing fierce market competition. All refineries attach great importance to reducing the cost of their products. Reducing the hydrogen cost of products is a systematic project that needs comprehensive consideration. Because of the specific circumstances of each refinery, in the hydrogen plant design process, the investment and operating costs should be comprehensively considered based on the prices of specific raw materials, fuels, and steam. The user's special needs minimize the cost of hydrogen by choosing the right water-to-carbon ratio, the temperature and pressure of the converter's inlet and outlet, and the proper application of pre-conversion processes and conversion processes.