Q&A on Purification Technology Version [008]

1) Stable operation: The catalyst used in this process does not tend to become deactivated, and with an appropriate selection of medium-temperature catalysts, the entire catalyst system can function properly for more than three years； Since the required H2S concentration at the inlet is not high, corrosion of the equipment is reduced compared to the full low-temperature shift process; it is also adaptable to higher oxygen levels in the gas produced, and reverse sulfidation does not occur easily in the low-temperature shift catalyst. 2) Energy consumption is relatively stable: The energy consumption of this process is slightly higher than that of the full low-temperature shift process, but it can drop to 200–250 kg/t·NH3 steam when the activity of the medium-temperature shift catalyst is high at the initial stage. Over the entire operation period, the energy consumption is generally around 300–400 kg/t·NH3; if a wetting process is used, steam consumption will be lower. 3) Reduced resistance: The catalyst loading for the medium-low-low process and the full low-temperature shift process is roughly comparable; it is significantly lower compared to that in the medium-high-low process, resulting in a corresponding decrease in resistance. Due to the higher reaction temperature range in the medium-temperature shift process as well as the vapor-to-gas ratio, the resistance remains somewhat higher than that in the full low-temperature shift process, at around 0.6 kg/cm2. Manufacturers that employ inter-stage gas cooling achieve a relatively lower resistance, with some achieving as low as 0.4 kg/cm2. 4) High operational flexibility: In the medium-low-low process, the variable outlet CO level can be adjusted within the range of 4% to 15% throughout the entire application cycle; it can be as low as 4% at the beginning and as high as 15% later on. A low variable outlet CO level can range from 0.3% to 13%, allowing it to meet the requirements of different subsequent processes. **The typical CO levels are 8–10% at the medium shift outlet, 3–5% at the low shift outlet, and <1.5% at the second low shift outlet. 5) Good operability for technological upgrades: Manufacturers using the medium-string low process can upgrade to a medium-low-low process; such manufacturers only need an equipment investment of around 100,000 yuan. Manufacturers using the full-low conversion process have surplus equipment available for upgrades, the process is shortened, and the low-conversion catalyst can also be reused. The time required for technical upgrades is also short; technically, only the pipelines need to be adjusted, and 1–2 temperature-regulating water heaters or humidifiers need to be added, with a technical upgrade time of 3–7 days.

1) Stable operation: The catalyst used in this process does not tend to become deactivated, and with an appropriate selection of medium-temperature catalysts, the entire catalyst system can function properly for more than three years； Since the required H2S concentration at the inlet is not high, corrosion of the equipment is reduced compared to the full low-temperature shift process; it is also adaptable to higher oxygen levels in the gas produced, and reverse sulfidation does not occur easily in the low-temperature shift catalyst. 2) Energy consumption is relatively stable: The energy consumption of this process is slightly higher than that of the full low-temperature shift process, but it can drop to 200–250 kg/t·NH3 steam when the activity of the medium-temperature shift catalyst is high at the initial stage. Over the entire operation period, the energy consumption is generally around 300–400 kg/t·NH3; if a wetting process is used, steam consumption will be lower. 3) Reduced resistance: The catalyst loading for the medium-low-low process and the full low-temperature shift process is roughly comparable; it is significantly lower compared to that in the medium-high-low process, resulting in a corresponding decrease in resistance. Due to the higher reaction temperature range in the medium-temperature shift process as well as the vapor-to-gas ratio, the resistance remains somewhat higher than that in the full low-temperature shift process, at around 0.6 kg/cm2. Manufacturers that employ inter-stage gas cooling achieve a relatively lower resistance, with some achieving as low as 0.4 kg/cm2. 4) High operational flexibility: In the medium-low-low process, the variable outlet CO level can be adjusted within the range of 4% to 15% throughout the entire application cycle; it can be as low as 4% at the beginning and as high as 15% later on. A low variable outlet CO level can range from 0.3% to 13%, allowing it to meet the requirements of different subsequent processes. **The typical CO levels are 8–10% at the medium shift outlet, 3–5% at the low shift outlet, and <1.5% at the second low shift outlet. 5) Good operability for technological upgrades: Manufacturers using the medium-string low process can upgrade to a medium-low-low process; such manufacturers only need an equipment investment of around 100,000 yuan. Manufacturers using the full-low conversion process have surplus equipment available for upgrades, the process is shortened, and the low-conversion catalyst can also be reused. The time required for technical upgrades is also short; technically, only the pipelines need to be adjusted, and 1–2 temperature-regulating water heaters or humidifiers need to be added, with a technical upgrade time of 3–7 days.

1) Stable operation: The catalyst used in this process does not tend to become deactivated, and with an appropriate selection of medium-temperature catalysts, the entire catalyst system can function properly for more than three years； Since the required H2S concentration at the inlet is not high, corrosion of the equipment is reduced compared to the full low-temperature shift process; it is also adaptable to higher oxygen levels in the gas produced, and reverse sulfidation does not occur easily in the low-temperature shift catalyst. 2) Energy consumption is relatively stable: The energy consumption of this process is slightly higher than that of the full low-temperature shift process, but it can drop to 200–250 kg/t·NH3 steam when the activity of the medium-temperature shift catalyst is high at the initial stage. Over the entire operation period, the energy consumption is generally around 300–400 kg/t·NH3; if a wetting process is used, steam consumption will be lower. 3) Reduced resistance: The catalyst loading for the medium-low-low process and the full low-temperature shift process is roughly comparable; it is significantly lower compared to that in the medium-high-low process, resulting in a corresponding decrease in resistance. Due to the higher reaction temperature range in the medium-temperature shift process as well as the vapor-to-gas ratio, the resistance remains somewhat higher than that in the full low-temperature shift process, at around 0.6 kg/cm2. Manufacturers that employ inter-stage gas cooling achieve a relatively lower resistance, with some achieving as low as 0.4 kg/cm2. 4) High operational flexibility: In the medium-low-low process, the variable outlet CO level can be adjusted within the range of 4% to 15% throughout the entire application cycle; it can be as low as 4% at the beginning and as high as 15% later on. A low variable outlet CO level can range from 0.3% to 13%, allowing it to meet the requirements of different subsequent processes. **The typical CO levels are 8–10% at the medium shift outlet, 3–5% at the low shift outlet, and <1.5% at the second low shift outlet. 5) Good operability for technological upgrades: Manufacturers using the medium-string low process can upgrade to a medium-low-low process; such manufacturers only need an equipment investment of around 100,000 yuan. Manufacturers using the full-low conversion process have surplus equipment available for upgrades, the process is shortened, and the low-conversion catalyst can also be reused. The time required for technical upgrades is also short; technically, only the pipelines need to be adjusted, and 1–2 temperature-regulating water heaters or humidifiers need to be added, with a technical upgrade time of 3–7 days.

1. Easy to operate 2. Low steam consumption 3. Long catalyst lifespan

1) Medium-variant catalysts have strong resistance to poisons and a longer lifespan than low-variant catalysts. 2) It features high heat recovery efficiency, resulting in significant energy savings. 3) Less catalyst is required, resulting in a decrease in system resistance. 4) High conversion of organic sulfur, purifying the gas. 5) High conversion rate.

Stable operation, stable energy consumption, reduced resistance

1. The industrial process is simple, with stable operation. 2 The energy consumption is relatively stable. 3 The system can handle large volumes of gas, resulting in reduced resistance. 4 It offers great operational flexibility and ease of use

1. The industrial process is simple, with stable operation. 2 The energy consumption is relatively stable. 3 The system can handle large volumes of gas, resulting in reduced resistance. 4 It offers great operational flexibility and ease of use

1. The industrial process is simple, with stable operation. 2 The energy consumption is relatively stable. 3 The system can handle large volumes of gas, resulting in reduced resistance. 4 It offers great operational flexibility and ease of use

1) Stable operation; 2) Relatively stable power consumption; 3) Reduced resistance; 4) High operational flexibility; 5) Good feasibility for technical upgrades