1. Preface
  The T504 ambient temperature organic sulfur hydrolysis catalyst is mainly used for precision desulfurization in the production processes of ammonia, methanol, polyols, low-carbon alcohols, synthetic fuels, urban gas methanation, food grade CO₂, synthetic polypropylene, etc. COS can be removed to<0.03ppm. At the same time, it can also be used for the removal of high content COS in semi water gas, water gas, coke oven gas, etc. This catalyst also has good removal effects on CS₂and chlorides.
This catalyst was first adopted by small and medium-sized methanol plants in China. In April 1993, it passed the expert appraisal jointly presided over by the Ministry of Chemical Industry and Hubei Province, and was deemed that its main technical indicators such as room temperature activity, H2S resistance, antioxidant performance, and service life were superior to similar products at home and abroad, belonging to the international leading level. It was officially named T504 type organic sulfur hydrolysis catalyst by the chemical fertilizer catalyst standard technical centralized unit of the Ministry of Chemical Industry, and is the only official product of the national brand among similar products. The T504 catalyst has the following characteristics:
1. Good activity at room temperature. Under the conditions of 30 ℃ and 6000h-1 airspeed, the COS conversion rate is greater than 90%.
2. Strong anti H₂S and O₂poisoning ability and long service life.
3. Good mechanical strength, does not pulverize when in contact with water, and has low bed resistance.

II. Physical and Chemical Properties of Catalysts

III. Reaction Principle and Quality Inspection Standards
1. Reaction principle
COS or CS₂reacts with residual water vapor in the feed gas to generate CO₂and H2S. The generated H₂S is then desulfurized with T101 activated carbon to achieve the goal of refined desulfurization. The reverse is:
COS + H₂O = H₂S +CO₂    △H = -35.5KJ/mol

2. Laboratory quality inspection indicators
The T504 organic sulfur hydrolysis test index is:
COS conversion rate≥ 90%;
Compressive strength: 25N/piece
Testing conditions:
Catalyst particle size ф 2-4mm; Pressure: normal pressure; Temperature: 30 ℃; Airspeed 6000h-1;
Raw gas: N2 containing 100-500ppm H2O, COS  5～15mgS/Nm³。

IV. Normal Operation and Usage Conditions
1. Normal operation control indicators:
(1) Airspeed: 2000-3000h-1
(2) Temperature: Room temperature~100 ℃ (generally 20-30 ℃ higher than the dew point of the gas)
(3) Pressure: atmospheric pressure~8.0MPa;
(4) Temperament requirements: Imported H₂S≤ 10mgS/Nm³, COS≤ 10mgS/Nm³

2. Factors affecting the service life of hydrolysis catalysts
The main factors affecting the service life of hydrolysis catalysts are sulfur content, oxygen content, and temperature. In the presence of O₂, H₂S in the feed gas reacts with O₂:
2H₂S + O₂ = 2S + 2H₂O          S + O₂ = SO₂ 
Sulfur is generated at low temperatures, and sulfate is generated at high temperatures. Sulfur mainly blocks the micropores of the catalyst, while sulfate reacts with the active centers on the catalyst surface, with the latter having a much greater impact on the lifespan of the catalyst than the former. Therefore, it is required to perform the operation; Three lows and one strictness; Imported H₂S is low, O₂content is low, and it is strictly prohibited to let water enter the catalyst bed.