This pre-heated the incoming gas to 400–500 °C and in doing so abstracted
almost all the heat from the exhaust gas. This was why the term ‘heat
regenerator’ was coined. Passing over the electrical heating element, the
incoming gas was economically raised to the desired temperature by the time
it entered the ‘contact chamber’. Fixation then occurred. The mixture
streamed out of the furnace through the fine capillary tubes of the regenerator, simultaneously pre-heating more incoming gas, and by cooling, moving
its own equilibrium position towards the formation of ammonia. By the time
it reached the second heat exchanger it was practically at room temperature.
Indeed, the two men reported
15 that the end of the tube nearest the furnace
could be held quite ‘comfortably in the hand’. The gas then passed through
the copper ‘plait’ of the second exchanger into the liquefier where the
ammonia was removed—the gauge glass indicating the amount developed.
Passing out of the liquefier, the cooled ‘remainder’ gas entered the exchanger
for a second time but now through the tube surrounding the ‘plait’. Here, the
relatively warm gas passing through the plait heated it up before the pump
sent it back to the furnace. On the side closest to the liquefier, the second
exchanger eventually developed a thick coating of ice whilst on the side
nearest the furnace it was at room temperature, hence the term ‘cold
regenerator’ was coined to describe it. In continuous operation, ammonia
could be removed as a liquid or ‘blown off’ in gaseous form whilst replacement gas mixture was simultaneously added to the system via the valve
connected to the high-pressure reservoir.
The ‘furnace’ and circulation machines were used to examine a wide variety
of potential ‘contact substances’. At the time little was known about catalytic
activity, Robert recalling that ‘we knew this was a way to help reactions to go in
the right direction but the choice was often a matter of trial and error …’.
7 The
two men had already examined chromium, manganese, iron, nickel and
platinum in their previous two papers. All these materials were meticulously
prepared in belief that impurities would seriously impair the efficacy of the
catalysts but none of these ‘cut the mustard’, i.e. generating reasonable
reaction rates and yields at ‘low’ enough temperatures. Others such as palladium, iridium and ruthenium had no catalytic effect at all. But then, and
not for the first time in the history of the ammonia synthesis, chance
intervened.
170
D. Sheppard
almost all the heat from the exhaust gas. This was why the term ‘heat
regenerator’ was coined. Passing over the electrical heating element, the
incoming gas was economically raised to the desired temperature by the time
it entered the ‘contact chamber’. Fixation then occurred. The mixture
streamed out of the furnace through the fine capillary tubes of the regenerator, simultaneously pre-heating more incoming gas, and by cooling, moving
its own equilibrium position towards the formation of ammonia. By the time
it reached the second heat exchanger it was practically at room temperature.
Indeed, the two men reported
15 that the end of the tube nearest the furnace
could be held quite ‘comfortably in the hand’. The gas then passed through
the copper ‘plait’ of the second exchanger into the liquefier where the
ammonia was removed—the gauge glass indicating the amount developed.
Passing out of the liquefier, the cooled ‘remainder’ gas entered the exchanger
for a second time but now through the tube surrounding the ‘plait’. Here, the
relatively warm gas passing through the plait heated it up before the pump
sent it back to the furnace. On the side closest to the liquefier, the second
exchanger eventually developed a thick coating of ice whilst on the side
nearest the furnace it was at room temperature, hence the term ‘cold
regenerator’ was coined to describe it. In continuous operation, ammonia
could be removed as a liquid or ‘blown off’ in gaseous form whilst replacement gas mixture was simultaneously added to the system via the valve
connected to the high-pressure reservoir.
The ‘furnace’ and circulation machines were used to examine a wide variety
of potential ‘contact substances’. At the time little was known about catalytic
activity, Robert recalling that ‘we knew this was a way to help reactions to go in
the right direction but the choice was often a matter of trial and error …’.
7 The
two men had already examined chromium, manganese, iron, nickel and
platinum in their previous two papers. All these materials were meticulously
prepared in belief that impurities would seriously impair the efficacy of the
catalysts but none of these ‘cut the mustard’, i.e. generating reasonable
reaction rates and yields at ‘low’ enough temperatures. Others such as palladium, iridium and ruthenium had no catalytic effect at all. But then, and
not for the first time in the history of the ammonia synthesis, chance
intervened.
170
D. Sheppard