What are the consequences of too much or too little steam in a medium-frequency furnace?

If too much steam is added, the CO level at the converter outlet will decrease; in addition, steam consumption will increase； If too little steam is added, the CO level at the converter outlet will increase. Adding too much or too little will have a significant impact on subsequent processes.

Furthermore, an excessive amount of steam input may also cause a decrease in the temperature of the catalyst bed.

In production, it is generally advisable to use a smaller amount of steam for the conversion process. Since less steam is used in this process, the overall steam consumption of the conversion system decreases, which in turn reduces the energy consumption associated with ammonia synthesis and thus lowers costs. When the amount of steam used in the shift reaction is too high, the CO level at the exit of the shift reactor decreases, and this also lowers the temperature at the hot spots within the reactor. Therefore, when the amount of steam used is reduced, the temperature at those hot spots rises ； Generally, we reduce the steam consumption of the conversion furnace in order to cut costs, but operators prefer to use the steam pressure temperature in order to avoid exceeding the limits (hot spot temperature), even if this means using an excessive amount of steam ； To this end, we need to determine a reasonable amount of steam required – that is, the amount of steam necessary to achieve the desired composition at the outlet of the converter – and then do everything possible to meet this target.

Only a portion of the steam used for conversion is involved in the conversion reaction, while most of it is used to regulate the temperature of the catalyst bed. Excessive use of steam reduces the outlet CO level, but it increases consumption and the resistance in the conversion system. Using too little will cause the outlet CO level to rise, even exceeding the limit, and it is difficult to control the peak temperature in the catalyst bed. Therefore, it is necessary to select an appropriate steam-to-gas ratio that ensures the desired CO levels at the converter outlet and the furnace temperature, while also reducing consumption.

Adding too much or too little steam to the conversion system has an impact on both the conversion system itself and the subsequent processes； Adding an excessive amount of steam can ensure the CO content at the system outlet; aside from what those upstairs have mentioned, it can also cause reverse sulfidation in the low-temperature conversion catalyst, thereby affecting its service life. If too little steam is added, in addition to the effects mentioned above, it will also cause excessive reduction of the medium-temperature catalyst, thereby affecting its service life.

Our high-temperature shift unit does not have a dedicated steam pipeline; steam is supplied from the furnace. The optimal water-to-carbon ratio is 3.4–3.5; a lower ratio results in poor conversion efficiency. Some plants use a water-to-carbon ratio of 3.1–3.2, and we reduced ours to 3.3 as well, but this led to a 1-ton decrease in carbon dioxide output at the outlet of the regeneration tower. What is your plant’s water-to-carbon ratio?

What the people upstairs said makes sense, but there’s one thing that hasn’t been taken into account: if too much steam is used, condensation water will definitely form, which will render the adhesive on the surface of the high-temperature catalyst ineffective and thus shorten the lifespan of the coal storage system