Dividing wall column in a fluid catalytic cracking gas plant for naphtha absorption, stripping, and stabilization service
AssigneeKellogg Brown & Root LLC
InventorsBhari Bhujan Singh, Ian Charles Elgey
Life of this patent
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Abstract
Methods and systems for recovering naphtha blend stock from hydrocarbons produced in a fluid catalytic cracking (FCC) process. In particular, the disclosure concerns gas plants for an FCC process, wherein the gas plant uses a dividing wall column. The dividing wall column essentially performs the functions that are performed in a traditional FCC gas plant by three different columns, namely, a primary absorber, a stripper, and a debutanizer.
Claims24
A method for recovering naphtha blend stock from hydrocarbons produced in a fluid catalytic cracking (FCC) process, the method comprising:
- compressing a wet gas from the FCC process, wherein the wet gas comprises C2-C5+ materials,
- fractionating the compressed wet gas to provide a vapor portion and a liquid portion,
- combining the vapor portion and the liquid portion in a dividing wall column, wherein:
- the dividing wall column comprises:
- a vertical dividing wall dividing a top section of the column into a pre-fractionator section and a main fractionator upper section that is contiguous with a main fractionator lower section configured below the vertical dividing wall,
- wherein the vapor portion and the liquid portion are combined in the pre-fractionator section,
- fractionating the combined vapor portion and liquid portion in the pre-fractionator section to provide a C2− enriched overhead stream and a C3+ enriched fraction,
- feeding the C3+ enriched fraction to the main fractionator lower section,
- fractionating the C3+ enriched fraction in the main fractionator lower section and main fractionator upper section to provide a C3/C4 enriched overhead stream and a C5+ enriched bottoms stream,
- recycling a first portion of the C5+ enriched bottoms stream to the pre-fractionator section, and
- recovering a second portion of the C5+ enriched bottoms stream as the naphtha blend stock.
A system for recovering naphtha blend stock from hydrocarbons produced in a fluid catalytic cracking (FCC) process, the system comprising:
- a compressor configured to compress a wet gas from the FCC process, wherein the wet gas comprises C2-C5+ materials,
- a separator drum configured to fractionate the compressed wet gas to provide a vapor portion and a liquid portion,
- a dividing wall column comprising a vertical dividing wall dividing a top section of the column into a pre-fractionator section and a main fractionator upper section that is contiguous with a main fractionator lower section configured below the vertical dividing wall, wherein the system is configured so that:
- the vapor portion and the liquid portion are combined in the pre-fractionator section,
- the combined vapor portion and liquid portion are fractionated in the pre-fractionator section to provide a C2− enriched overhead stream and a C3+ enriched fraction,
- the C3+ enriched fraction is fed to the main fractionator lower section,
- the C3+ enriched fraction is fractionated in the main fractionator lower section and main fractionator upper section to provide a C3/C4 enriched overhead stream and a C5+ enriched bottoms stream,
- a first portion of the C5+ enriched bottoms stream is recycled to the pre-fractionator section, and
- a second portion of the C5+ enriched bottoms stream is recovered as the naphtha blend stock.
Dependencies are inferred from the claim text.