Hydrogen production started
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The hydrogen production plant has been put into operation; why is the constant-temperature period kept relatively long? What are the conditions for introducing steam? Some sources state that the inlet temperature for conversion should be ≤550°C – why is that? I saw some information stating that steam and hydrogen are supplied simultaneously; isn’t it supposed to be steam first, followed by hydrogen? When adding hydrogen, how is the water-to-hydrogen ratio calculated? In the hot nitrogen cycle, after switching the hydrogen supply and changing the feed material, what is the pattern of changes shown by the flow meter?
The constant temperature is generally maintained during the furnace drying stage for catalyst dehydration, and during the sulfidation phase; the steam supply temperature should be above 420°C at the inlet and above 450°C at the outlet, in order to prevent water vapor from condensing and to ensure that superheated steam is supplied. Depending on the staffing arrangement, hydrogen and steam can be supplied simultaneously, while if they are supplied separately, hydrogen should be added within 30 minutes after steam supply. The water-to-hydrogen ratio should be greater than 3 and less than 7. The purpose of adding steam is mainly to improve the gas flow and prevent excessive reduction of the catalyst. If the water-to-hydrogen ratio is greater than 7, the reduction effect is poor, which will prolong the time required for reducing the catalyst. Moreover, adding too much steam also increases energy consumption.