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T201 Organic sulfides Hydroconversion Catalyst
Release date: 2015-10-14 & Source: & Views: 539
  • Detailed introduction

    1. Features and Scope of Application

    Some catalysts used in hydrocarbon-based large-scale ammonia plants is sensitive to sulfur compounds and prone to be poisoned and deterioration in activity when sulfur content in feed gas exceeds certain value. Cobalt –molybdenum hydroconversion catalyst and zinc oxide are usually used for desulfurization of feed gases or oils.

    T201 hydroconversion catalyst, with high organic sulfur conversion capability, is applicable to hydroconversion of feed gases for large-scale ammonia plants. It can bring down organic sulfur in feed gases to less than 0.1 ppm.

    Main hydroconversion reactions involved are as follows:

    RSH+H2  =  RH+H2S

    R1SSR2+3H2  =  R1H+R2H+H2S

    R1SR2+2H2  =   R1H+R2H+H2S

    C4H4S+4H2 =   C4H10+H2S

    COS+H2   =   CO+H2S

    where  R=alkyl groups.

    This product is also applicable to organic sulfur hydroconversion of light oils or gaseous hydrocarbons in petrochemistry.

    2. Physical properties


    3.Quality norm

    According to HG2505-93 industrial standard, catalyst T201should conform to following norm:


    4. Reference operating conditions


    The hydrogenation reactions take place at 300-450℃. Initial temperature is usually controlled at 350-380℃. If sulfur concentration in feed oil stays below a certain limit ( i.g. , 0.2ppm) for long term, “Sulfur discharge” phenomenon will take place. Therefore, for two-section oil hydrogenation system, operating temperature in 1st section should be such that ensures sulfur concentration of 2—10ppm in effluent naphtha , so as to maintain the catalyst in 2nd section in sulfided state.

    5. Loading

    (1)Clean the reactor of any debris and screen the catalyst of any powder before loading. Operators working inside the reactor should stand on a broad wooden plate without stepping directly on the catalyst.

    (2)Install inert balls at the top and bottom of the reactor . The catalyst particles are separated from the inert balls by stainless wire net of smaller mesh size than the catalyst.

    (3)Use a funnel connected by a S-type cloth tube to drop the catalyst slowly and evenly from a maximum height of 1.2m to the reactor while holding lower end of the tube to prevent breakage of the particles.

    (4)The loading operators should not stand directly on the catalyst bed during loading.

    6. Start-up and Catalyst Presulfiding


    Purge the system with nitrogen or other gases and then warm up the catalyst bed with nitrogen, hydrogen-nitrogen or natural gas. Warming-up procedure: 30~50℃/h to 120℃, keep at 120℃ for 2 h, and then 30~50℃/h to 220℃. Then carry out presulfiding while warming up.

    Usually presulfiding is not necessary for first-time use of the catalyst when using natural gas, associated gas or light naphtha as feedstock, since inorganic sulfur in the gaseous feed may fulfill sulfiding gradually during operation. However, in the case of treating hydrocarbons with high and/or complicated sulfur , presulfiding is need for first-time use to attain higher hydrogenation activity. Sulfur absorbed amounts to about 5% of total weight of the catalyst at the end of presulfiding.

    Presulfiding can be done in following two ways:

    (1)Adding CS2 into nitrogen or hydrogen

    Add CS2  into feed gas (hydrogen-nitrogen or hydrogen) after warming up to 220℃. Carry out presulfiding while warming up at 20℃/h till operating temperature. Presulfiding can be considered complete when sulfur-containing gas equivalent to theoretical sulfur adsorbent capacity of the catalyst is added.

    Presulfiding condition:

    2)Adding CS2  into light oil(preferably light naphtha)

    Pass sulfiding medium into catalyst bed when bed temperature reaches 220℃. Keep on sulfiding while warming up at 20℃/h till operating temperature. Presulfiding can be considered complete when sulfiding medium equivalent to theoretical sulfur absorption capacity of the catalyst is added. Then raise pressure to operation condition, shift to hydrocarbon feed and adjust temperature, LHSV and hydrogen/oil, and and gradually proceed to normal full load operation.

    Properly enhance operating temperature in later service stage of the catalyst to increase its activit.

    Presulfiding condition

    7 Shutdown

    (1) Temporary shutdown

    For liquid feed, stop feed supply , purge the system for 1 h to remove any liquid hydrocarbon,  close inlet and outlet valves and maintain temperature and pressure in the reactor. For gaseous feed, cut feed supply and maintain the pressure.

    (2)Long-term shutdown

    For long-term shutdown without disassembly of the reactor, lower to 30% load, lower the temperature at 30-50℃/h to 250℃ and the pressure to 1.5MPa at no greater than 0.5MPa/h to avoid catalyst breakage. Then stop supply of feed , purge the system with hydrogen for 1 h, close inlet and outlet valves, maintain the pressure at positive (no less than 0.1MPa) and let the temperature drop naturally. For gaseous feed, Cut feed supply and bring down the pressure and temperature at above-mentioned rate.

    For long-term shutdown with disassembly of the reactor, purge the system with nitrogen, maintain positive pressure and bring down temperature to 40℃ disassembly.

    (3)Start-up after shutdown

    The same procedure as initial start-up. For liquid feed, to avoid reduction of the catalyst (especially over 250℃), warm up with nitrogen or inert gas until operating temperature. Then shift to feed oil and hydrogen. For gaseous feed, warm up directly with gaseous feed and hydrogen.

    When hydrogenating gas is used for the warming-up, pass hydrocarbon feed into the reactor immediately after the temperature exceeds dew point of the liquid hydrocarbon, and then continue warming-up till operating temperature.

    (4)Incidental shutdown

    Due to variety of causes of incidents, no general-purpose procedure can be given out for incidental shutdown. Following are tips to be paid attention to for avoiding harm to the catalyst:

    1 Lowering temperature at over 50℃/h when reactor temperature is higher than 200℃ is harmful to both strength and activity and service life of the reactor.

    2 The reactor can tolerate short time interruption of hydrogen supply (several minutes). Long time interruption may cause coke formation on the catalyst, sometimes so serious that regeneration or changeover is necessary.

    3  Long-term contact with sulfur-free hydrogen at over 250℃ may cause reduction and hence activity loss of the catalyst.

    8. Regeneration

    Activity of the catalyst may deteriorate with service time due to coke formation. When this deterioration becomes intolerable to operation requirement, it is necessary to regenerate the catalyst.

    Shut down according to the procedure for “long-term shutdown without disassembly” . Bring down temperature to 250℃ and pressure to atmospheric and then pass air-containing steam ( 0.5-1.0% oxygen) into reactor for regeneration. Increase oxygen concentration in the steam with temperature rise till totally air . Maintain at 450℃ (maximum 475℃) for 4h after there is no temperature rise and oxygen concentration at the inlet and outlet becomes equal. Then regeneration can be considered completed.

    When rapid temperature rise is observed while increasing oxygen concentration in steam, stop adding air and pass solely steam to relief temperature rise. Resume and increase addition of air when temperature becomes normal. Exothermal reaction may take place and cause remarkable temperature rise at 350-400℃. Strictly control air addition and prevent damage to the catalyst by temperature surge.

    Analysis of oxygen and CO2 concentration in outlet stream is helpful to inspect progress of regeneration. Regeneration can be considered completed when oxygen in inlet and outlet stream approaches the same. Continue to pass air flow and bring down temperature at 40~50℃/h to 220℃. Then shift to nitrogen purging and presulfiding and finally normal operation.

    Regeneration cycle is 2-3 years under normal operation condition.

    9. Package and Storage

    The catalyst is packed in iron barrel lined inside with plastic bags. It should be stored in dry and cool place. The catalyst usually can be stored for several years without remarkable deterioration in properties and activity.

    During the regeneration to prevent temperature surge which may cause loss of activity of the catalyst.




The product name:T201 Organic sulfides Hydroconversion Catalyst
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