Abstract: Processes and apparatus for quantitatively converting urea to ammonia on demand are disclosed. One process includes the steps of: receiving a demand rate signal for ammonia; feeding reactants including urea and water into a reactor to provide a reaction mixture; and controlling temperature and pressure in the reactor to produce a gaseous product stream including ammonia and carbon dioxide at substantially constant concentrations. Another process includes the steps of: feeding molten urea or solid urea to a reactor; feeding water (liquid or steam) to the reactor; and reacting the urea and water at elevated temperature and pressure to form a gaseous product stream including ammonia and carbon dioxide.

Abstract: A method of removing solvents from a paste includes introducing a heated paste into a channel of a dryer under pressure selected so as to avoid flashing of any of the components of the paste. At the inlet of the channel, the pressure is dropped, resulting in the flashing of selected components of the paste. As the paste advances through the channel heat is applied to the paste. Vapor liberated during the flashing acts as a motive force to convey the paste along the channel. The resulting concentrate is collected at an outlet of the channel.