Catalyst

[Fetsch]

When comparing catalyst prices, should one compare the cost per weight of catalyst or cost per volume of catalyst? The catalyst pellets are similar in size and have similar compositions but one is reported with an 18% higher bulk density than the other.

 

[m777182]

As a basis for the calculacions of a plant efficiency is the mass balance and because you are buying and paying catalyst per mass units it would be wise to compare efficiency per mass unit although you need some more calculations to get it.But however, compare apples to apples and pears to pears.
m777182

 

[katmar]

Catalyst prices should be compared on the productivity in terms of product made. It does not matter whether one is cheaper than another in terms of volume or mass of catalyst. All that counts is how much product you make for each dollar spent on calatyst.

 

[tmc1]

Normally, catalyst productivity is measured on how many kg of catalyst used to make one metric ton of polymer produced.
And before it is used, it needs to be activated to make it active and this process involves some weight loss like moisture and other volatiles.

 

[25362]

Costs of production including catalysts' useful lifes should be added in the economic analysis.

 

[epoisses]

Not all of the above is true IMHO.
First of all, catalyst, even presulfided, is paid on oxidic weight basis, so weight losses during in-situ activation are not relevant.

You may want to check the basis of the densities of the two cats, are both oxidic basis, are the measurement methods comparable? What about the void fractions, does one of the two give you a pressure drop advantage?

Then, know what the objective of your reactor: do you want to fill it with cheap cat for a low-severity service, you will want to take the cheapest per volume that does the job.

If you need the highest activity possible, ask your research lab to compare the iso-volume activities (the denser one is not necessarily more active) and see if the delta activity outweighs the delta price. Is troughput limited by this reactor's performance or by something else? Difference in expected lifetimes of both cats can be calculated from delta operating temperature (calculated from delta activity) versus max EOR temp assuming equal stability which may or may not be the case.

Yes it gets quite complicated if you want to do it right! Can't give you an easy recipe. Anyway, don't hesitate and make those cat vendors sweat for you, ask them for a design and compare the two.

 

[epoisses]

PS check also the regen/rejuvenation price, Type II cats are much more active than conventional but it's more expensive to achieve maximum activity recovery.
How often the cat can be regenerated depends 99% on your operation (feed quality), check the unit history.

 

[epoisses]

PS PS - Have you considered buying regenerated cat?

 

[liberoSimulation]

If I remember well that the price depends on the gross volume of the catlyst to be provided by the vendor with some additional volume percentage (about 5%) due to losses during loading activities.
The gross volume will be calculated based on knowing the weight of the catalyst and its density.

Hope this would help you.

Cheers
Simulator

 

[Fetsch]

We have not considered buying regenerated catalyst. I doubt we would be able to find any regenerated sour gas shift catalyst.

 

[Yordif]

Sour Gas Shift catalysts (catalyst that can perform the water - gas shift reaction in a high sulfur enviroment) have typically been sold on a volume basis. I do not believe that you will find any regenerated versions of the catalyst and there are only a couple of manufacturers. The two main ones that I know are Johnson Matthey and Unicat.

If I remember right, this is a mainly a Gross Surface Area reaction that is diffusion limited. You will need to see check the difference in metals loading between the two catalysts. Basically you are looking for accessible metal so bulk density may not actually give you more accessible active metal.

I would check the reference list for the catalyst and see if you can get any run length details on a simlar plant to your own. There are only a handful of sour shift applications in North America but I understand that Asia has a lot.

Hope this helps