LHSV

[Homayun]

Hi,

Can anyone tell me what exavtly is the "Liquid Hourly Space Velocity"? I think it must be some sort of required velocity in a reactor that is needed for a proper reaction.


who can help me with this?

I appreciate it.

 

[25362]

The definition I'm used to: LHSV is the ratio of the hourly volume of oil processed to the volume of catalyst. It is generally expressed as v/v/hr or
hr^-1. As such it controls the residence time of the liquid reactants in typically cylindrical reactors.

For example, in hydrodesulfurization of petroleum products it has been found that the residual sulfur content is proportional to the LHSV. LHSV values for naphthas as high as 12 v/v/h have been employed depending on other parameters such as T, P, hydrogen-rich gas rates, etc.
In comparison, vacuum residue feedstocks require LHSV values in the range of 0.1-0.5 v/v/hr.

 

[Eltron]

You can also check out thread124-138409 for a short discussion of space velocity.

Hope that helps.

 

[UmeshMathur]

Hi, Homayun:

In heterogeneous catalysis, LHSV is usually based on feed rate in standard barrrels per day or per hour divided by either the mass or the superficial volume (not including the void fraction) of catalyst. Increasingly, I see use of catalyst mass over volume, since commercial sale is on a mass basis.

LHSV is simply an approximate way of estimating the amount of catalyst one would need to purchase for a given feed capacity and product yield. (This assumes that the reactor design and operating conditions are otherwise adequate to ensure the proper conversion and selectivity.)

 

[Homayun]

Thank you all for your help.

great