What reaction is catalyzed by the catalyst? Normally reduction is performed to obtain a phase that is catalyctically active like metallic Ni instead of NiO or Ni(NO3)2.

By definition, the catalyst function is to lower the activation energy for a given reaction so that the reaction would occur at a lower temperature. Accordingly, the catalyst should not part of the gasification reaction and should not react with the steam for example in the gasification reaction.

It is always a trial and error experimental process just to determine how much catalyst to use. Any excess catalyst that is not needed to lower the reaction activation energy is considered to be a waste, especially for an expensive element such as nickel.

Professor Yehia Khalil, Yale University, USA

Fellow of the University of Oxford, UK

The use of Ni catalyst for gasificaiton reactions indicates that it will be a heterogeneous catalyst that will provide a favorable surface for the reaction to proceed at a lower activation energy mechanism.

The gaseous reactants usually get adsorbed "chemisorption" which enhances their reactivity towards each other & this facilitates the formation of the product(s).

Once the product(s) is/are formed, the new substance(s) leave the surface "desorption". All through, the catalyst did not participate in the reaction as reactant or intermediate so it is difficult to think of reduction or oxidation of catalyst during the progress of a gaseous reaction.

When elemental carbon deposits on the surface of a heterogeneous catalyst , the catalyst becomes deactivated and this cannot be described as reduction. It is just that the active sites on the surface have been covered by C particles.

Pd catalyst also may need to be reduced under a reductive environment, often H2, in order to "activate" them. Various groups have found that Pd-O surface coatings form on catalyst surfaces blocking active sites and also modifying the electronic nature of the catalyst surface. The removal of these surface species often times enables catalysis.

At our side the catalyst is calculated perfectly and we know how much catalyst we need as a fixed bed catalyst and also we use the catalyst as sulfide form and the sulfur atoms should be enough to desirable yield

because we are purchase the catalyst by tons so we must to know how much amount we need as economically and to save our budget especially with expensive types as most of transition metals

actually reduction or oxidation the catalyst in case of hydrotreater or hyd rocracker are very great problem because if it occurs the catalyst would to be poison

We need to reduce ,if you don't recover the catalyst it may go in waste which creates a pollution problems due to variable oxidation states of metal.

Can you explain me the reason for double reduction peaks during gasification process?

Second peak is NiO to Ni. First peak is Ni2O3 to NiO