Process for drying high-lactose aqueous fluids

A process for drying high-lactose aqueous fluids, the process comprising the steps of:

• concentrating a high-lactose aqueous fluid containing from about 1 to about 35% solids, wherein at least 50% of the solids are lactose, to form a hot, highly concentrated high-lactose aqueous fluid containing from about 70 to about 80% solids;
• transferring the hot, highly concentrated high-lactose aqueous fluid into a cooling, concentrating, crystallizing apparatus in which a cooling, concentrating, crystallizing cascade is created by exposing highly concentrated high-lactose aqueous fluid to a gaseous fluid, which is effective to cool and further concentrate the hot, highly concentrated high-lactose aqueous fluid in a manner that causes lactose solids within the hot, highly concentrated high-lactose aqueous fluid to crystallize so as to generate a partially crystallized high-lactose aqueous fluid containing from about 78 to about 88% solids;
• and
• spraying the partially crystallized high-lactose aqueous fluid into a chamber containing hot air to form a solids product rich in crystalline lactose.

A method of substantially drying a partially crystallized high-lactose aqueous fluid containing from about 78 to about 88% solids, at least 50% of which are lactose;

• the method comprising the steps of:
• providing an air-lift dryer, including an enclosed drying chamber having an atomizing inlet for introducing atomized partially crystallized high-lactose aqueous fluid into the enclosed drying chamber;
• the enclosed drying chamber having an upper portion and a lower portion, a primary air inlet and an exhaust air outlet;
• the atomizing inlet and the primary air inlet being located in the lower portion;
• and introducing atomized partially crystallized high-lactose aqueous fluid into the enclosed drying chamber via the atomizing inlet with sufficient fluid pressure to drive atomized partially crystallized high-lactose aqueous fluid upward within the enclosed drying chamber in a direction at least partially in opposition to a gravitational force acting on the atomized partially crystallized high-lactose aqueous fluid.

A process for drying high-lactose aqueous fluids, the process comprising the steps of:

• providing a partially crystallized high-lactose aqueous fluid containing from about 78 to about 88% by weight solids;
• wherein the solids contain at least about 50% by weight lactose;
• providing a dryer for drying particles in a gravitational environment, the dryer including:
• an enclosed chamber having a top and a bottom;
• wherein a gravitational force is placed upon particles in the enclosed chamber when the spray dryer is standing upright in the gravitational environment such that particles in the enclosed chamber will move from an area proximate the top in a generally downward direction toward the bottom when no other force is placed upon the particles;
• and wherein movement from an area proximate the bottom toward the top is movement in an upward direction;
• the enclosed chamber having an intermediate section having diverging sidewalls and an increasing horizontal cross-sectional area as the enclosed chamber extends upward in a direction away from the bottom;
• a pressurized particle feed opening arranged and constructed within the enclosed chamber to spray particle containing aqueous fluid upward into the enclosed chamber;
• a gas feed opening arranged and constructed within the enclosed chamber to direct a pressurized flow of a gas fluid upward into the enclosed chamber in a direction generally the same as the direction of particles sprayed by the pressurized particle feed;
• simultaneously, spraying the partially crystallized high-lactose aqueous fluid upward into the enclosed chamber through the particle feed opening and feeding hot air upward into the enclosed chamber through the gas feed opening at a temperature of from about 100 to about 250 degrees Celsius (° C.).

A method of further concentrating a highly concentrated high-lactose aqueous fluid containing from about 70 to about 80% solids, wherein at least about 50% of the solids are lactose;

• the method comprising the steps of:
• introducing the highly concentrated high-lactose aqueous fluid into a cooling, concentrating, crystallizing apparatus in which the concentrated high-lactose aqueous fluid is exposed to a gaseous fluid effective to create a cooling, concentrating, crystallizing cascade which utilizes the heat of crystallization from the crystallization of lactose within the concentrated high-lactose aqueous fluid to drive the cooling, concentrating, crystallizing cascade forward to generate a partially crystallized high-lactose aqueous fluid containing from about 78 to about 88% solids;
• and
• spraying the partially crystallized high-lactose aqueous fluid into a chamber containing hot air to form a high-solids crystalline product rich in crystalline lactose.

A method of crystallizing lactose from a highly concentrated high-lactose aqueous fluid containing from about 70 to about 80% solids, wherein at least about 50% of the solids are lactose and the temperature of the highly concentrated high-lactose aqueous fluid is greater than about 50 degrees Celsius, the method comprising the steps of:

• introducing the highly concentrated high-lactose aqueous fluid into a cooling, concentrating, crystallizing apparatus in which the highly concentrated high-lactose aqueous fluid is exposed both to mixing and to movement of a gaseous fluid at a temperature, moisture content and air speed effective to create a cooling, concentrating, crystallizing cascade in which evaporative cooling causes loss of moisture and an increase in solids which in turn facilitate lactose crystallization which in turn releases lactose's heat of crystallization which in turn increases fluid temperature which in turn facilitates more evaporative cooling, so that a partially crystallized high-lactose aqueous fluid containing from about 78 to about 88% solids is generated;
• and
• spraying the partially crystallized high-lactose aqueous fluid into an enclosed drying chamber containing hot air to form a high-solids crystalline product rich in crystalline alpha-lactose monohydrate crystals;
• wherein the high-solids crystalline product contains some residual moisture and from about 90 to about 99% solids, wherein from about 80 to about 100% of the residual moisture in the high-solids crystalline product is incorporated within alpha-lactose monohydrate crystals.