Operating Process Principle of Catalysts for Hydrogen Production from Methanol Cracking
2020.08.04
In recent years, increasingly stringent environmental protection regulations, growing demand for high-standard clean fuels, as well as the heavy and high-sulfur nature of crude oil have all boosted the demand for hydrogen in oil processing. The demand for hydrogen is most intense in its application fields. Hydrogen production via methanol cracking has developed rapidly to fill the hydrogen supply gap.
As a manufacturer of catalysts for hydrogen production from methanol cracking, Suzhou Jiarui Gas hereby explains the operating process principle of such catalysts:
Operating Process Principle of Catalysts for Hydrogen Production from Methanol Cracking
After preheating and vaporization, methanol and water enter the methanol cracking reactor, where the following reactions take place under the action of a catalyst:
The overall reaction process is endothermic, so the heat required by the reactor and vaporizer is supplied by a heat medium furnace. The temperature of the circulating heat medium (heat transfer oil) is 280~320 ℃. The endothermic cracking reaction and exothermic shift reaction proceed simultaneously, which makes efficient use of reaction heat and eliminates potential hot spots caused by exothermic reactions.
Among catalysts for methanol cracking to hydrogen, copper-based catalysts were the earliest researched and most widely used. Compared with catalysts of other systems (see Table 1), copper catalysts feature high activity and good selectivity. However, they have low poison resistance, and overheating tends to cause sintering and deactivation. At present, copper-based catalysts are mostly adopted in China.
Operating Process Flow of Catalysts for Hydrogen Production from Methanol Cracking
Methanol feedstock comes from the storage tank and is mixed with water from the bottom of the water washing tower in a certain proportion.
The mixture is heated and vaporized through a methanol preheater and a methanol vaporizer. The vaporized methanol and steam enter a tubular reactor, where cracking and shift reactions occur respectively under the action of the catalyst.
Process water is pumped to the top of the water washing tower to scrub the cracked gas. The gas phase at the tower top enters a Pressure Swing Adsorption (PSA) unit for hydrogen purification after liquid separation, while the liquid phase at the tower bottom is recycled and mixed with feed methanol (see Figure 1).
The PSA unit consists of multiple adsorption towers to realize continuous hydrogen separation. Its working process includes adsorption, pressure equalization and depressurization, counter-current depressurization, flushing (or vacuum evacuation), pressure equalization and repressurization, and product repressurization.
The above is the operating process principle of catalysts for hydrogen production from methanol cracking, compiled and released by Suzhou Jiarui Gas, a manufacturer of catalysts for methanol cracking to hydrogen.
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