2 replies to this topic

[ayan_dg]

Benzene service has been defined as more than 1% Benzene by weight in hydrocarbon stream. My question is at what pressure class we should use double block and bleed isolation for pumps , control valves and instrument. Is it 300# or 600# ? What is the general consensus weighing in operator safety and projects total installed cost

[fallah]

Benzene service has been defined as more than 1% Benzene by weight in hydrocarbon stream. My question is at what pressure class we should use double block and bleed isolation for pumps , control valves and instrument. Is it 300# or 600# ? What is the general consensus weighing in operator safety and projects total installed cost

 

Hi,

 

It's obvious starting from lower pressure class to do so is much better, but for your query you have to follow the relevant project design criteria describing the conditions in which DBB configuration should be considered...

[ayan_dg]

Fallah,
Thanks for your reply. Actually we are making that criteria. We are writing the isolation philosophy. I just want to know what is the general criteia followed in industry related to streams which have high Benzene content. It is carcinogenic but not toxic like H2S. Our Client has not specified Benzene service as “lethal” not they have specified it to be catergory M.