A desalination system and method for controlling the desalination system include thin-filmed photocatalyst coated glass tubes which perform a photocatalytic cleaning reaction to remove contaminants. A first flow control valve directs the contaminant-free feed water either to a feed water heater for pre-heating or to a geothermal energy-based heat exchanger. A second flow control valve directs a first portion of the pre-heated contaminant-free feed water to a thermal energy storage tank and a second portion to a flash chamber for steam generation. A condenser connected to the flash chamber includes a nano-fluid cooling coil that condenses steam into potable water.

A process for purifying a urea-containing aqueous stream, such as the aqueous stream from the recovery section of a urea plant, comprising a step of removing biuret from the urea-containing stream by reverse osmosis in one or more reverse osmosis stages.

A nozzle assembly is mountable in a passage of a lid of a gas cooler. Heated gas containing acidic or acid-forming constituents flows into the gas cooler through the nozzle assembly. The nozzle assembly includes a liner having an upper end and a lower end, and the liner is made from material that is corrosion resistant to a condensate of the heated gas. The nozzle assembly also includes a deflector upstream of the liner that reduces a cross-sectional area of the passage to increase a concentration of the acidic or acid-forming constituents at the liner so that, under cooling of the heated gas as the heated gas passes the liner, the heated gas condenses adjacent the liner in a band between the upper and lower ends