Process of removing calcium and obtaining sulfate salts from an aqueous sugar solution

A process for obtaining a product stream comprising one or more sulfate salts of monovalent cations selected from the group consisting of potassium, sodium, ammonium, and combinations thereof, from a sugar stream resulting from the hydrolysis of a lignocellulosic feedstock, said sugar stream comprising calcium sulfate and one or more sulfate salts of the monovalent cations, said process comprising the steps of:

• (i) treating the sugar stream to remove calcium by passing the sugar stream through a cation exchange resin bed to bind calcium to the resin bed, thereby producing a sugar stream containing substantially no calcium ions, wherein cations of one or more of the sulfate salts of the monovalent cations present in the sugar stream comprising calcium sulfate also bind to the resin bed, and wherein a salt stream comprising a calcium salt is obtained by regenerating the cation exchange resin bed with a regenerant to form a regenerated stream comprising one or more soluble salts of the monovalent cations bound to said resin and a soluble calcium salt;
• (ii) obtaining a clarified salt stream derived from the regenerated stream of step (i) after precipitation and removal of calcium therefrom, said clarified salt stream comprising at least one of potassium, ammonium and sodium salts;
• (iii) introducing the clarified salt stream of step (ii) to a cation exchange resin bed;
• and
• (iv) regenerating the cation exchange resin bed of step (iii) with sulfuric acid to produce the product stream.

A process for obtaining a product stream comprising one or more sulfate salts of monovalent cations selected from the group consisting of potassium, sodium, ammonium, and combinations thereof, from a sugar stream resulting from the hydrolysis of a lignocellulosic feedstock, said sugar stream comprising calcium sulfate and one or more sulfate salts of the monovalent cations, said process comprising the steps of:

• (i) treating the sugar stream to remove calcium by passing the sugar stream through a cation exchange resin bed to bind calcium to the resin bed, thereby producing a sugar stream containing substantially no calcium ions and containing one or more of the monovalent cations present in the sugar stream comprising calcium sulfate;
• (ii) introducing the sugar stream containing substantially no calcium ions of step (i) to a cation exchange resin bed;
• (iii) regenerating the cation exchange resin bed of step (ii) with sulfuric acid to produce the product stream;
• and
• (iv) regenerating the cation exchange resin bed of step (i) with a regenerant to form a regenerated stream comprising a soluble calcium salt.

A process for obtaining a product stream comprising one or more sulfate salts of monovalent cations selected from the group consisting of potassium, sodium, ammonium, and combinations thereof, from a sugar stream resulting from the hydrolysis of a lignocellulosic feedstock, said sugar stream comprising calcium sulfate and one or more sulfate salts of the monovalent cations, said process comprising the steps of:

• (i) treating the sugar stream to remove calcium by passing the sugar stream through a chelating resin bed to bind calcium to the resin bed, thereby producing a sugar stream containing substantially no calcium ions and containing one or more of the sulfate salts of the monovalent cations present in the sugar stream comprising calcium sulfate;
• (ii) introducing the sugar stream containing substantially no calcium ions of step (i) to a cation exchange resin bed;
• (iii) regenerating the cation exchange resin bed of step (ii) with sulfuric acid to produce the product stream;
• and
• (iv) regenerating the chelating resin bed of step (i) with a regenerant to form a regenerated stream comprising a soluble calcium salt.