metgal47:
Refineries do not "decide" to make more or less spent caustic (containing NaHs) from one day to another day. It is waste product and they produce whatever amount is needed to remove H2S from their naphtha, kerosene, jet fuel, or LPG streams being caustic scrubbed.
Again, as I said in response another of your questions on this same general subject, I strongly suggest that you read the book "Aqueous Wastes from Petroleum and Petrochemical Plants", by M.R. Beychok, published by John Wiley in 1967. It is available in most good university libraries.
Milton Beychok
(Visit me at www.air-dispersion.com)
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