Multiple grade flush adsorption separation process

A process for the separation of a product from a multicomponent feedstream to a simulated moving-bed adsorption apparatus, said product comprising paraxylene in a product concentration, and said process comprising:

• introducing said feedstream through at least one fluid communication conduit into said apparatus;
• flushing said at least one conduit with a sufficient quantity of a first flushing medium drawn from a first source and comprising paraxylene in a first concentration less than said paraxylene product purity concentration of said product such that feedstream residue is flushed from said at least one conduit into said apparatus by said at least one first flushing medium;
• flushing said at least one conduit with a sufficient quantity of said product drawn from a second source in a paraxylene product purity concentration, such that any residue from said first medium is flushed from said conduit into said apparatus by said product;
• and
• withdrawing said product from said apparatus;
• wherein said first source is separate from said second source and at least one of said first source and said second source is separate from said apparatus.

A process for the separation of a product from a multicomponent feedstream, said product comprising at least one desired component, and said process comprising:

• introducing said feedstream through at least one fluid communication conduit into a system comprising adsorbent material;
• flushing said at least one conduit with a sufficient quantity of at least one initial flushing medium drawn from a first source and comprising said at least one desired component in an initial concentration, such that feedstream residue is flushed from said at least one conduit into said system by said at least one initial medium;
• flushing said at least one conduit with a sufficient quantity of a final flushing medium drawn from a second source and comprising said at least one desired component in a final concentration, such that said final concentration is greater than said initial concentration, and such that initial medium residue from said at least one initial medium is flushed from said conduit into said system by said final medium;
• withdrawing a raffinate stream from said system;
• introducing a desorbent stream to said system;
• withdrawing a combination comprised of said product and said desorbent from said system;
• and
• removing said product from said combination, wherein said first source is separate from said second source and at least one of said first source and said second source is separate from said system.

A process for the separation of a product from a multicomponent feedstream to an adsorption apparatus, said product comprising at least one desired component, and said process comprising:

• introducing said feedstream through at least one fluid communication conduit into said apparatus,
• flushing said at least one conduit with a sufficient quantity of at least one initial flushing medium comprising said at least one desired component in an initial concentration, such that feedstream residue is flushed from said at least one conduit into said apparatus by said at least one initial medium;
• flushing said at least one conduit with a sufficient quantity of a final flushing medium comprising a desorbent such that initial medium residue from said at least one initial medium is flushed from said conduit into said conduit into said apparatus by said final flushing medium;
• and
• withdrawing said product from said apparatus.