Conversion Reaction in Hydrogen Production Unit

Conversion Reaction in Hydrogen Production Unit 

Reaction principle

Hydrocarbons and water vapor pass through the conversion catalyst bed.At high temperature, water vapor and hydrocarbons undergo cracking reactions to generate H2, CO, and CO2. The reaction formula as follows:

(1) CnHm ＋ nH2O → nCO ＋ H2 -Q

(2) CO ＋ H2O → CO2 ＋ H2 +Q

Influencing factors

①　Temperature:

The conversion reaction is a strong endothermic reaction.Increasing the temperature is beneficial to the reaction.But the bearing capacity of the furnace tube should be considered. Generally, the surface temperature of the furnace tube is controlled not to exceed 930°C.

②　Pressure:

The conversion reaction process is a reaction process in which the volume increases.Increasing the reaction pressure is detrimental to the reaction process.Since industrial hydrogen is generally used in high-pressure chemical processes.Therefore, considering the overall energy saving, the conversion process is generally carried out under pressure.

③　Water carbon ratio:

The water-to-carbon ratio is a term used to express the operating conditions of a hydrogen reformer.It refers to the ratio of the total number of water (steam) molecules to the total number of carbon atoms in the conversion feed. Written as H2O/C.The water-to-carbon ratio is the most sensitive process parameter in the light oil conversion process.In production, increasing the water-to-carbon ratio can reduce the carbonization of the catalyst.It is very beneficial to the conversion reaction to reduce the residual methane at the outlet of the bed.However, increasing the water-to-carbon ratio also increases energy consumption.Therefore, in production, the appropriate water-to-carbon ratio can only be determined according to the specific process equipment.The water-carbon ratio of the device is controlled at 3.5-5.

④　Airspeed:

Generally, the conversion load is expressed by liquid volume space velocity or carbon space velocity.The larger the space velocity, the shorter the time that the raw material stays in the reforming catalyst bed.The worse the reaction depth is, the higher the residual methane at the outlet of the reformer and the carbonation of the reforming catalyst increases.The carbon space velocity of this device adopts 1000h-1.