4 replies to this topic

[Venkat @89]

Dear all,

My organization has got two diesel hydrotreaters one designed and commissioned by Axens in 2011 with NiMo and CoMo catalyst and other by Haldor toposoe in 2020 with only NiMo catalyst.

Axens deigned hydrotreater required system pressure is 59.4kgf/cm2g and H2/HC ratio minimum at reactor inlet is 160, whereas for Haldor toposoe design, the system pressure required is 45kgf/cm2g and H2/HC ratio minimum at reactor inlet is 320. Why does diesel hydrotreater of two different process licensor has different system pressure and H2/HC ratio?

I would like to understand, what factors decide, the values of System pressure and H2/HC ratio?

[shvet1]

Share please design conditions:

- H2 partial pressure in reactors

- S in feeds and products

Edited by shvet1, 09 October 2022 - 10:36 PM.

[breizh]

Hi,

Should be the result of an optimization versus Catalyst formulation!

You may ask a technical assistance from your licensors to support your query.

 

Good Luck

Breizh 

[PingPong]

Dear all,

My organization has got two diesel hydrotreaters one designed and commissioned by Axens in 2011 with NiMo and CoMo catalyst and other by Haldor toposoe in 2020 with only NiMo catalyst.

Axens deigned hydrotreater required system pressure is 59.4kgf/cm2g and H2/HC ratio minimum at reactor inlet is 160, whereas for Haldor toposoe design, the system pressure required is 45kgf/cm2g and H2/HC ratio minimum at reactor inlet is 320. Why does diesel hydrotreater of two different process licensor has different system pressure and H2/HC ratio?

I would like to understand, what factors decide, the values of System pressure and H2/HC ratio?

Main reactor parameters are:

- hydrogen partial pressure

- temperature

- catalyst properties (composition, pore size, pore surface area)

- catalyst quantity (resulting space velocity)

 

Licensor will select these parameters based on the feed and product specifications that the client provided when the contract was signed.

A client feed with high S and N and aromatics and ASTM T95, and client product requirement of low S and aromatics will all impact those parameters.

 

The hydrogen partial pressure in the reactor increases both with the reactor pressure as well as the hydrogen recycle rate.

Axens used a higher pressure but a lower recycle rate, HT apparently did the opposite.

Obtaining a certain reactor H2 partial pressure can be achieved with many different combinations of reactor pressure and H2/HC ratios.

 

The design specs for the 2011 Axens unit and the design specs for the 2020 Haldor Topsoe unit may be different, even if both units today run on the same feedstock. Check and compare the original Basis Of Design (BOD) of both units.

 

Moreover different licensors have different design philosophies and use different safety margins to assure that product specs are met in a guarantee testrun.

[SilverShaded]

Was the higher pressure unit designed for de-aromotisation or cold property improvement?