| 摘要 |
In an exothermic gas reaction, the reactant gases are compressed (at 12) and passed through a reaction zone (14) and the resulting mixture of gases is expanded through an expansion engine (15) driving the compressor, and recycled for further reaction, products being removed at any convenient stage (e.g. 11). The compressor and engine are both preferably turbines of over 75% efficiency. Heat may be exchanged (at 13) between gases entering and leaving the reaction zone. Extra energy may be supplied as heat to the reactant gases or reaction zone, or to the compressor by means of a steam turbine or electric motor. Surplus energy may be removed by means of a generator which is coupled to the expansion engine and used to supply energy during start-up. In the synthesis of NH3 from N2 and H2 using a Fe oxide catalyst, the pressure of the reactant gases before and after compression may be, respectively 20-80 atm., and at least 100, e.g. 200-400 atm. NH3 may be removed (at 11) by freezing, or may be absorbed in water and the remaining gases dried by refrigeration or by means of a bed of solid desiccant, e.g. silica gel, which is continuously cycled between said bed and a regeneration bed situated between 11 and 13. Purge gases are removed (at 16) to recover inert gases, e.g. argon. Examples give specific temperatures and pressures at each stage.ALSO:In an exothermic gas reaction, the reactant gases are compressed (at 12) and passed through a reaction zone (14) and the resulting mixture of gases is expanded through an expansion engine (15) driving the compressor, and recycled for further reaction, products being removed at any convenient stage (e.g. 11). The compressor and engine are both preferably turbines of over 75% efficiency. Heat may be exchanged (at 13) between gases entering and leaving the reaction zone. Extra energy may be supplied as heat to the reactant gases or reaction zone, or to the compressor by means of a steam turbine or electric motor. Surplus energy may be removed by means of a generator which is coupled to the expansion engine and used to supply energy during start-up. In the synthesis of NH3 from N2 and H2 using a Fe oxide catalyst, the pressure of the reactant gases before and after compression may be, resp., 20-80 atm., and at least 100, e.g. 200-400 atm. NH3 may be removed (at 11) by freezing, or may be absorbed in water and the remaining gases dried by refrigeration or by means of a bed of solid disiccant, e.g. silica gel, which is continuously cycled between said bed and a regeneration bed situated between 11 and 13. Purge gases are removed (at 16) to recover inert gases, e.g. argon. Examples give specific temperatures and pressures at each stage. Reference is also made to the synthesis of methanol from carbon oxides and hydrogen. |
