Hello all, we are replacing an e
Hello all, we are replacing an e
(OP)
Hello all,
we are replacing an existing turboexpander-compressor with new smaller size one due to lower plant inlet flow.
the capacity of the compressor has changed from 345 mmscfd at normal operations to 115 mmscfd. with this new expander-compressor, the need for recycle flow on the compressor has changed. My question is what is the effect of the smaller compressor capacity on the current size of the anti-surge valve? We are planning to change only the expander-compressor with no other chagnes. Do we need to reduce the Cv of the anti-surge valve? I found that the current Cv valve requires 1% opening for 5 mmscfd recycle flow. What are the risks of using this big size anti-surge valve in controlling such small flow? at 115 mmscfd the opening will be 22%.
Please advise how I can analyze the situation of surge control with the smaller compressor capacity?
I appreciate your inputs.
Iradah
we are replacing an existing turboexpander-compressor with new smaller size one due to lower plant inlet flow.
the capacity of the compressor has changed from 345 mmscfd at normal operations to 115 mmscfd. with this new expander-compressor, the need for recycle flow on the compressor has changed. My question is what is the effect of the smaller compressor capacity on the current size of the anti-surge valve? We are planning to change only the expander-compressor with no other chagnes. Do we need to reduce the Cv of the anti-surge valve? I found that the current Cv valve requires 1% opening for 5 mmscfd recycle flow. What are the risks of using this big size anti-surge valve in controlling such small flow? at 115 mmscfd the opening will be 22%.
Please advise how I can analyze the situation of surge control with the smaller compressor capacity?
I appreciate your inputs.
Iradah





RE: Hello all, we are replacing an e
I would generate new sizing data and discuss it with your Instrumentation engineer how they feel the control will operate with the existing trim versus a new valve or trim (you can very likely get a custom trim made for your existing valve if you want). A new valve trim is a minor cost.
RE: Hello all, we are replacing an e
i have never seen an anti-surge valve sized for 100% of the flow. So if you only need to pass ~33% of the flow, your valve would be about 7% open if the system is dead-headed.
RE: Hello all, we are replacing an e