Methods and systems for spray drying temperature sensitive products

A method of spray drying using a vacuum spray drying system, comprising:

• experimentally determining an outlet temperature to achieve a minimum drying rate at an atmospheric pressure based on a selected liquid feed and a selected liquid to gas ratio, wherein the selected liquid feed includes a liquid phase and a product;
• calculating a predicted dryer pressure at which the minimum drying rate can be reached at a reduced outlet temperature with respect to a drying rate change relative to the minimum drying rate using a model based on a liquid feed drop which is pure liquid phase to approximate formation of a shell of the product on the liquid feed drop, wherein the reduced outlet temperature is less than a maximum temperature;
• and
• spray drying the selected liquid feed at the selected liquid to gas ratio, the predicted dryer pressure, and the reduced outlet temperature via the vacuum spray drying system, wherein the vacuum spray drying system includes a drying chamber to receive the selected liquid feed and a vacuum pump fluidly coupled to the drying chamber to reduce an operating pressure within the drying chamber and wherein the predicted dryer pressure is in a range between 0.01 bar up to 0.05 bar below ambient pressure.