2 replies to this topic

[ally01389]

Hi all,

 

A client in the spirits industry has asked me to review the sizing basis for their pressure relief valves on their stills.

 

I've done some quick rough checks and I am concerned that their existing relief valves may be undersized.

 

Some specfic questions I have, before I get into a more thorough review:

 

1. Are there any other specific codes / standards I should be aware of relating to pressure relief of stills for spirit production?  In addition to the usual standards pertaining to overpressure protection (e.g. BS EN ISO 4126 / 23251 / etc.)

2. Are there any other good engineering practices / conventions I should be aware of relating to pressure relief of stills for spirit production?

 

Thanks in advance for any help or advice anyone is able to provide.

 

 

Additional Background Info:

 

The client doesn't have a huge amount of information on their existing relief valves.  They have some basic datasheets / inspection / test certificates which give orifice sizes, set pressures, and max. relieving pressures, but they don't give any details of the sizing cases used or the rated flows of the relief valves.  The supplier is notoriously difficult to get any additional information out of - I'm not holding my breath for them to be able to answer any questions that we may try to put to them.

 

I'm an experienced process engineer, however I'm relatively new to the spirits industry (my background is mostly oil & gas), so I'm looking for some general advice on over/underpressure protection of stills, as there may be relevant codes/standards, or typical practices I'm unfamiliar with, etc.

 

I'm based in the UK - specifically Scotland, as is my client.  So we are bound by Scottish / UK legislation and generally work to BS EN ISO standards.

 

Another thing to note in this case is the design pressure of the stills and the set and relieving pressures of the relief valves all are below 0.5 barg, therefore it is my understanding that the Pressure Equipment Directive (PED) and Pressure Equipment Regulations (PER) do not apply.

[Bobby Strain]

You should use API or ASME standards to evaluate relief valves. Or greater importance is to look at the disposition of relief valve discharges. My experience is with fuel alcohol in the USA. I found some liquid relief valves discharging to the immediate area at grade. The low pressure design for the equipment requires a relief valve at the bottom of the column to protect against liquid overfilling. I even found some columns using only a single pressure switch, not a relief valve, to protect against overpressure.

 

So, you are likely evaluating a big mess.

 

Bobby

[breizh]

HI,

General guidelines for Safety valves in the industry : https://www.aiche.or.../20131068_r.pdf

The difficult part should be to define the scenarios , in particular for vacuum . In the food industry they are using steam to clean and sanitize the units , this could lead to equipment collapsing if cold water is introduced or sprayed over the equipment .

 

For overpressure you may consider the cases mentioned in the document attached ,if relevant .

 

Breizh