2 replies to this topic

[ryn376]

We are working for a tolling manufacturer who has over 240 independent chemicals that can be added into their reactors. Is there a generalized chemical/properties we can use in lieu of evaluating all of them? Even if we did evaluate all of them, there are a near infinite number of combinations of chemicals since these chemicals are manually batched in by the operators (the plant does not have a DCS). How can we size these relief devices? The client recommended using heptane to evaluate the vapor scenario, but we cannot find a basis for that assumption anywhere in literature. Note: we are going to Fauske to evaluate reactive scenario relief rates. I have another idea how to handle this, but I want to get everybody's ideas first. 

[fallah]

We are working for a tolling manufacturer who has over 240 independent chemicals that can be added into their reactors. Is there a generalized chemical/properties we can use in lieu of evaluating all of them? Even if we did evaluate all of them, there are a near infinite number of combinations of chemicals since these chemicals are manually batched in by the operators (the plant does not have a DCS). How can we size these relief devices? The client recommended using heptane to evaluate the vapor scenario, but we cannot find a basis for that assumption anywhere in literature. Note: we are going to Fauske to evaluate reactive scenario relief rates. I have another idea how to handle this, but I want to get everybody's ideas first. 

 

ryn376,

 

It might you get the properties of the heavier gas as a basis for sizing of all PSV's but then the sized PSV's for light gases might be over sized; and more importantly the run away reaction in the reactors might be credible and brings the products into play while they might not already be included in initial evaluation...

[ryn376]

Yes, the difficulty is that there are so many chemicals that we will not be able to evaluate them all. We will make sure to use rupture discs to prevent any chattering that could occur for lower relieving rates. Even still the sizing procedure is unknown since we cannot find properties for all the chemicals. If there is no guidance on a generalized chemical to use in lieu or an actual one, we are sort of stuck...