Abstract: An ammonia plant having a first and second reactor and a start-up oven having at least one first heat exchanger. The first reactor operates under a higher internal pressure than the second reactor. The start-up oven is connected via a piping system for at least one synthesis gas to the first and second reactor. Ammonia is produced by heating synthesis gas in the start-up oven and transferring the heated synthesis gas to the first reactor for initiating the chemical reaction. Synthesis gas is heated with the same start-up oven and is transferred to the second reactor for initiating the chemical reaction, wherein high-pressure synthesis of ammonia occurs in the first reactor and low-pressure synthesis of ammonia occurs in the second reactor at a lower process pressure than in the first reactor.

Abstract: A multiway slide valve having a housing provided with a graduated cylindrical guide bore, a pressure inlet port, and a pair of pressure outlets ports. A preassembled valve seat unit including a plurality of annular spacers which carry sealing rings having respective diameters corresponding to the graduations of the guide bore so that damage to the sealing rings is prevented when inserted into the graduated cylindrical guide bore. A slide spool and jacket inserted into the guide bore. A cover attached to the housing for depressing the jacket which causes deformation of the sealing rings to provide a tight seal between the graduations of the guide bore and the slide spool.