Use of hydrocarbon steam reforming catalysts

1. Deactivation and regeneration of steam reforming catalysts

The main causes of steam reforming catalyst activity decline are carbon accumulation, poisoning and sintering, in addition to incomplete reduction or gradual passivation of the reformed catalyst. As the catalyst activity decreases, the industry usually adopts a gradual and small increase in outlet temperature to maintain normal production. When the temperature can no longer be increased, the catalyst has to be replaced.

Different catalyst deactivation causes and different regeneration methods are used. In the case of serious carbon analysis, the raw material must be removed before the regeneration of charring with water vapor, and air charring is not suitable, but a small amount of air can be added to the steam for charring if necessary; for reversible sulfur poisoning, regeneration by analysis is used; the regeneration process of conversion catalyst for chlorine poisoning includes two processes of steam purification and reduction.

2. Loading of steam reforming catalyst

A section of the reforming catalyst is loaded in hundreds of vertically suspended reforming tubes with trays or screens at the bottom of the tubes. The filling should be done in such a way that the process gas is evenly distributed among the tubes. The ideal filling condition is to fill each tube with the same volume, height and weight of catalyst. However, when the same amount of catalyst is loosely filled or tightly filled in the furnace tube, the corresponding stack density can vary by about 10%, i.e., the filling height and void rate vary greatly, which obviously affects the airflow distribution in operation, so every effort should be made to achieve uniform filling. Otherwise, the resulting uneven distribution will become a hidden problem in the system and cannot be eliminated during operation.

The catalyst should be sieved and inspected in the tube before loading, and should be filled and inspected in layers. Loading methods are divided into wet and dry methods.

The wet method causes more problems and the dry method is generally used.

The second stage conversion furnace is a vertical shaft furnace with large diameter, and the operator can enter the second stage furnace to work. After checking the arch and clearing all impurities and dust in the furnace, it should be calculated according to the design requirements, the expected filling amount and the size of the second stage furnace, and marked on the inner wall of the second stage furnace to calculate the height of the corundum ball or perforated brick, heat-resistant catalyst, conversion catalyst, bottom corundum ball of each layer, and then filled from the bottom to the top layer by layer until the predetermined height.

3. Reduction of steam conversion catalyst

Nickel oxide is not catalytic conversion activity, and usually conversion catalyst is mostly provided with titanium oxide, so it must be activated before use.