Reforming catalyst RK-11-1&RK-11-2 mainly used to the primary steam reforming plant for the production of synthetic ammonia, methanol and hydrogen by taking gaseous hydrocarbon mainly including methane as main body as raw material.
1.Physical properties and chemical components
1） Composition: nickel is the active component, and alumina with special additives is the carrier.
2） Appearance: grey black arc cylinder with six holes and double heads
Physical dimension (outer diameter * inner diameter * length):
Short grain RK-11-1: φ16*3.5*8mm (applied to the upper part of reforming pipe)
Long grain RK-11-2: φ16*3.5*16mm(applied to the lower part of reforming pipe)
The catalyst also can be other sizes or shapes required by customers.
3） Bulk density: 0.8-1.2 kg/L
4）Side crushing strength: ≥400N/p (long grain)
≥200N/p (short grain)
5）Burn weightlessness: ≤5%
Pressure: the atmospheric pressure - 5Mpa
Water/carbon ratio: ≥2.5
2.Requirements of catalyst to raw materials and poisons
1） Sulfur is the main poison of the thermal protective agent, so that the content of sulfur within the raw material gas entered into the furnace shall be reduced as far as possible; generally, the content of sulfur shall be less than 0.5ppm, and the best content of sulfur shall be less than 0.2ppm.
2）Chlorine and other halogens also will poison the catalyst, and inhibit the recovery of activity of the catalyst, so that the content of chlorine in the raw material shall be reduced as far as possible.
3）Arsenic will deactivate the catalyst permanently, so the raw material gas shall not include arsenic.
4） Copper, lead and the like can also reduce the activity of protective agent, so the raw material gas shall not include these poisons.
5）The water vapor used shall not include these poisons and the chemical drugs used for the treatment of boiler feed water.
3.Storage and loading of catalyst
1） The catalyst packed in plastic bag well shall be placed in a moisture-proof and anti-pollution iron drum or hard plastic drum to prevent from damping, freezing and shaking at any time, and it shall be prevented from falling from the place of 0.5m and above. Moreover, the catalyst shall be prevented from the pollution caused by sulfur or other soluble salts during the storing and transportation process.
2）Before feeding into the furnace, the catalyst shall be sieved to remove a small amount of powder therefrom, and the blocking condition for the interior of furnace and supporting grid shall be inspected.
3） The catalyst shall be loaded into the bag in batch, and it shall be placed lightly while placing in the furnace pipe, in which the entry of the bag shall be loosened, and the catalyst shall be prevented from mechanical wear.
4）During the process of loading catalyst, each furnace pipe shall be vibrated in division, so as to prevent from bridging. The weight and height of catalyst loaded shall be basically the same, so as to ensure the even loading of the catalyst.
5）Catalyst RK-11-1 shall be loaded on the upper part of the reaction pipe of reformer, and the catalyst RK-11-2 (long grain) shall be loaded on the lower part.
6） After the completion of loading catalyst, the furnace shall be blown with air, and the pressure drop shall be tested. The average value for pressure difference of each furnace pipe shall be +/-3-5% for the qualified loading condition.
4.Temperature-rising reduction of industrial catalyst
1）The catalyst can be heated to the reaction temperature in the atmosphere with water vapor, nitrogen, carbon dioxide, hydrogen, and ammonia. For the new catalyst, air also can be used as the heating medium at 200℃ and below, when the heating medium is water vapor, it shall be ensured that the temperature is higher than the dew point of the system pressure of 20℃ and above.
2）When the catalyst is heated to 650～800℃ at the speed of 30～50℃/h, there is no adverse effect to the performances of the catalyst at the speed of 100℃/h, and the actual temperature-rising speed is determined by the requirements on the body of reformer.
3）At present, the general heating speed of industrial device is 30～50℃/h, and the reduction operation can be carried out by heating from normal temperature to reduction temperature, in which the constant temperature of specific stages can be prevented. The catalysts RK-11-1& RK-11-2 is very good in adapting the rapid heating process recommended and adopted by some plants.
4） The reduction medium can be pure hydrogen or water vapor with raw material gas, wherein the water/carbon ratio can be controlled at 5-7 initially, and it can be adjusted to normal level gradually with the implementation and end of reduction.
5）Reduction pressure: 0.20 ~ 0.70MPa (gauge pressure); reduction temperature: 650 ~ 800℃; reduction air speed: 200～600h-1; and reduction time: when the temperature reaches to the reduction temperature specified, it shall be maintained for not less than 8h.
6） After starting reduction, the catalyst shall not be contacted with oxidation gas.
7）The content of sulfur in catalyst RK-11-1& RK-11-2 is few, so that there is no obvious phenomenon of sulfur release during the starting and temperature-rising reduction process.
8）The content of SiO2 in catalyst RK-11-1& RK-11-2 is few, so that there is no adverse impact caused by Si volatile migration during the operation process to the following system.
5.Notes in operation
1)In normal operation process, it shall be ensured that the water/carbon ratio is lower than the design value at any time.
2)In the operation, the water vapor shall be added before the raw material gas while increasing the load, and the raw material gas shall be reduced before the water vapor while reducing the load.
1)In normal operation state, the active component of catalyst is nickel in reduction state, so in the operation and shutting down process, the catalyst shall not be contacted with excessive oxidation gas, to prevent the bed layer of catalyst from serious overtemperature due to the intense oxidation of the catalyst. In case of short-term shutting down, the air of secondary reformer can be cut off, then the raw material gas of the primary reformer shall be closed, the water vapor fed to the primary reformer can be continued; at the same time, the fuel gas in burning nozzle of the primary reformer shall be closed to cool. When the temperature of primary reformer is reduced to the point above the dew point of water vapor for about 20-30℃, the water vapor within the system shall be blown off with nitrogen or air, so as to ensure that the temperature will be reduced to normal condition while keeping the pressure.
2)In case of long-term shutting down or replacement of catalyst, the catalyst shall be subject to passivation treatment, wherein the passivation medium shall be water vapor, the air of can be cut off, then the raw material gas of the first section shall be closed, the water vapor fed to the primary reformer can be continued for 6-8h, until the outlet gas of the secondary reformer does not include non-condensable gas, which can prove that the catalyst has been passivated basically. At this point, the fuel gas of the primary reformer can be closed, the water vapor fed to the primary reformer can be continued; when the cooling speed is about 50℃/h and the temperature is higher than the dew point for about 20-30℃/h, nitrogen shall be infused to cool to normal temperature, and then it can be regarded that the passivation and shutting down process are completed.
3)To give full play to the use of the catalyst, prolong its service life, the catalyst shall be prevented from long-term contacting with excessive water vapor at high temperature.
4)The cooling temperature of catalyst RK-11-1& RK-11-2 shall be mainly considered from the process equipment.
1) Treatment of catalyst poisoning
①When the reaction temperature of furnace pipe is relatively high, nickel catalyst poisoned sulfur is reversible, the water/carbon ratio operation can be increased properly by infusing the raw material gas of which the sulfur content is lower than the value specified in case of sulfur poisoning, and then the activity of the catalyst will gradually recover; however, if the poisoning condition is serious, activity cannot be recovered completely after treating, which means there is still adverse effect to the catalyst, so the condition of catalyst poisoning shall be prevented as much as possible.
②For catalyst poisoning based on chlorine and chlorides, regeneration is difficult, and the cost thereof is high, so chlorine and chlorides shall be strictly prevented from entering into the system of raw material gas.
③Arsenic poisoning will make permanent catalyst deactivation, so arsenic shall be strictly prevented from entering into the catalyst layer with water vapor.
2)Carbon deposition process of catalyst
①In case of small amount of carbon deposition of the catalyst, the natural gas can be reduced or the water vapor can be increased; meanwhile, the operation shall be carried out in the condition that the outlet temperature is 650～800℃, and the change of CO2 content in outlet shall be observed. When the CO2 content is normal, it can be regarded that carbon deposition process is completed, and the plant can be put into normal operation.
②When the carbon deposition of catalyst is serious, the general treatment effect is bad, and the suggestion is to replace the catalyst.