How can medium-low-low transformation and middle-string low transformation be distinguished?

Two low-temperature sections in sequence with one medium-temperature section: does this constitute medium-low-low conversion or medium-low conversion?

A medium-shift low-temperature reactor is generally one that contains three sections of medium-shift catalysts, with an outlet CO level of around 3-5%; following this is a low-shift reactor equipped with two sections of low-shift catalysts, whose outlet CO level is approximately 1%； The medium-low-low configuration typically consists of one medium shift converter equipped with a section of medium shift catalyst, with an outlet CO level of around 10%; followed by two low shift converters, each also equipped with a section of low shift catalyst, giving an outlet CO level of around 1%. The steam consumption in the medium-string low-process is generally around 500 kg/tNH3, while that in the medium-low-low process is around 250 kg/tNH3. In terms of the evolution of the shift process, it should be such that initially, all shift processes were of the medium-temperature type. After the low-shift catalyst was successfully developed, in order to increase production, reduce the CO content after conversion, and lower the steam consumption per ton of ammonia, an additional low-shift reactor was installed after the medium-shift reactor. This can reduce the steam consumption associated with the transformation, while increasing output. At this point we call it medium-string low. With the adoption of low-temperature catalysts, we have reduced the number of medium-temperature catalysts used in the design and increased the use of low-temperature catalysts. At this point, the function of the medium-temperature catalyst changes from mainly facilitating conversion to mainly serving to purify semi-water gas, that is, to remove O2 and tar from the semi-water gas. These two impurities are what low-temperature catalysts fear the most. Since the low-variation catalyst at this stage is designed with two layers in order to dissipate heat outward, we refer to such a design as medium-low-low. This is because at this point, the main task of conversion has shifted from the medium-conversion catalyst to the low-conversion catalyst