초록 ▼

Wash water is used to remove impurities such as hydrogen sulfide, ammonia, and hydrogen cyanide from light hydrocarbons and gases derived from refinery fluid catalytic cracking operations. The present invention is a process of low pressure recirculation of wash water combined with low pressure remov

Wash water is used to remove impurities such as hydrogen sulfide, ammonia, and hydrogen cyanide from light hydrocarbons and gases derived from refinery fluid catalytic cracking operations. The present invention is a process of low pressure recirculation of wash water combined with low pressure removal of waste water which results in the efficient removal of the above impurities at significantly reduced wash water rates.

대표청구항 ▼

[ I claim:] [1.] A process for water washing an overhead stream withdrawn from an FCC main fractionator of an FCC unit processing an FCC feedstock to remove impurities from the overhead stream, said process comprising:a) admixing said overhead stream with a first portion of a first water recycle str

[ I claim:] [1.] A process for water washing an overhead stream withdrawn from an FCC main fractionator of an FCC unit processing an FCC feedstock to remove impurities from the overhead stream, said process comprising:a) admixing said overhead stream with a first portion of a first water recycle stream at a low pressure ranging from about 140 to about 350 kPa to provide a combined overhead stream;b) cooling and at least partially condensing the combined overhead stream to provide a cooled overhead stream and passing the cooled overhead stream to a low pressure separator to provide a low pressure vapor stream, a low pressure liquid stream, and a low pressure aqueous stream;c) raising the low pressure vapor stream to an intermediate pressure ranging from about 525 to about 800 kPa to provide an intermediate vapor stream and admixing the intermediate vapor stream with a wash water stream and a second portion of the first water recycle stream to provide an intermediate pressure admixture;d) raising the intermediate pressure admixture to a high pressure ranging from about 1155 to about 1575 kPa to provide a high pressure stream and cooling and at least partially condensing the high pressure stream to provide a cooled high pressure stream and passing the cooled high pressure stream to a high pressure separator to provide a high pressure vapor stream, a high pressure liquid stream and a high pressure aqueous stream; and,e) recycling at least a portion of the high pressure aqueous stream as the first water recycle stream, and withdrawing a portion of the low pressure aqueous stream as a sour water stream.