A spray drying system for drying liquid into powder comprising: an elongated body supported in an upright position; a closure arrangement at opposite upper and lower ends of the elongated body for forming a drying chamber (12, 358) within the elongated body; one of the closure arrangements including a drying gas inlet for coupling to a heated drying gas source and for directing heated drying gas into the drying chamber (12, 358); an electrostatic spray nozzle assembly supported in one of the closure arrangements; said electrostatic spray nozzle assembly including a nozzle body having a liquid inlet for coupling to a supply of liquid, a discharge spray tip assembly at a downstream end for directing liquid to be dried into the drying chamber (12, 358) and an electrode for coupling to an electrical source for electrically charging liquid passing through the spray nozzle assembly into the drying chamber (12, 358), and said lower end closure arrangement including a powder collection vessel for collecting powder dried in the drying chamber (12, 358), an upper end of the powder collection vessel being in communication with the drying chamber (12, 358) characterized by: said powder collection vessel including a blanket gas inlet near the upper end of the powder collection vessel that communicates with a blanket gas supply and is configured such that blanket gas from the blanket gas supply is directed into the interior of the powder collection vessel to blanket the powder in the powder collection vessel and thereby protect the dried powder in the collection vessel from exposure to heat, moisture, and oxygen from the heated drying gas from the drying chamber (12, 358). an elongated body supported in an upright position; a closure arrangement at opposite upper and lower ends of the elongated body for forming a drying chamber (12, 358) within the elongated body; one of the closure arrangements including a drying gas inlet for coupling to a heated drying gas source and for directing heated drying gas into the drying chamber (12, 358); an electrostatic spray nozzle assembly supported in one of the closure arrangements; said electrostatic spray nozzle assembly including a nozzle body having a liquid inlet for coupling to a supply of liquid, a discharge spray tip assembly at a downstream end for directing liquid to be dried into the drying chamber (12, 358) and an electrode for coupling to an electrical source for electrically charging liquid passing through the spray nozzle assembly into the drying chamber (12, 358), and said lower end closure arrangement including a powder collection vessel for collecting powder dried in the drying chamber (12, 358), an upper end of the powder collection vessel being in communication with the drying chamber (12, 358) characterized by: said powder collection vessel including a blanket gas inlet near the upper end of the powder collection vessel that communicates with a blanket gas supply and is configured such that blanket gas from the blanket gas supply is directed into the interior of the powder collection vessel to blanket the powder in the powder collection vessel and thereby protect the dried powder in the collection vessel from exposure to heat, moisture, and oxygen from the heated drying gas from the drying chamber (12, 358).