38results about How to "Reduce secondary cracking reactions" patented technology

The invention discloses a process for hydrofining coking crude benzene, which consists of a raw-materialnits preseparating unit, a hydrofining unit, a predistillation unit, an extractive distillation, an aromatic-hydrocarbon refining unit and a xylene distillation unit, wherein supplementary hydrogen needed in reaction is supplied from the outside; a reaction part in the hydrofining unit adopts three-stage hydrogenation; and the temperature of second-stage hydrogenation and third-stage hydrogenation is 230 to 290 DEG C and 220 to 315 DEG C respectively. The process has the advantages that the temperature adopted in both the second-stage hydrogenation and the third-stage hydrogenation is greatly lower than the reaction temperature of the prior process; the process effectively reduces benzene transformed into cyclohexane, reduces the secondary cracking reaction of the cyclohexane, reduces the loss of aromatic compound, and improves the retention rate of aromatic hydrocarbon which can reach over 99.6 percent; meanwhile, the three-stage hydrogenation adopted in the reaction part prolongs the process of hydrogenation and ensures that sulfur-containing nitrogen-containing organic compounds can also be transformed into inorganic sulfur or inorganic nitrogen compounds at a lower temperature, so that the aim of purification is achieved; and the total content of both sulfur and total in a hydrofined product is less than 1 ppm.

The invention relates to a catalytic cracking diesel oil hydro-upgrading catalyst and applications thereof. The catalyst is composed of VIII-group and VIB-group hydrogenation active metal components and a carrier containing a modified Y molecular sieve, amorphous silicon aluminum and alumina; the modified Y molecular sieve is prepared from a NaY molecular sieve by the steps of carrying out ammonium exchange twice, carrying out roasting one time and carrying out hydro-thermal treatment one time. The catalyst is used for carrying out hydro-upgrading on distillate or catalytic cracking diesel oil at a temperature of 160-380 DEG C. After inferior diesel distillate of which the sulfur content is higher than 1000 mu g/g, the nitrogen content is higher than 1000 mu g/g, the aromatics content is higher than 55v% is treated by using the catalyst, the desulfurization rate and the denitrification rate are both higher than 98%, the cetane number is increased by more than 10 units, and the yield of the diesel distillate is over 98wt%.

The invention relates to a method for hydro-dearomatization in catalytic cracking of diesel. According to the invention, Ni and W are adopted as hydrogenation active metal components of a catalyst and modified Y molecular sieve, modified Beta molecular sieve, amorphous silica-alumina and alumina are adopted as carriers of the catalyst, wherein the average crystal size of the modified Y molecular sieve is 100-400nm, the mole ratio of SiO2/Al2O3 is 5-40:1; the relative crystallinity is greater than 90% and the specific surface area is 700-1000m<2>/g; the average crystal size of the modified Beta molecular sieve is 50-200nm, the mole ratio of SiO2/Al2O3 is 50-200:1; the relative crystallinity is greater than 85% and the specific surface area is 700-900m<2>/g. When the method is adopted to process inferior diesel fraction, the desulfurization rate and the denitrification rate are up to more than 97.5%, the dearomatization rate is up to more than 55% and the diesel fraction yield is up to more than 98wt%.

The invention relates to a low-grade heavy oil catalytic conversion process for increasing the yield of low-carbon olefins and diesel oil. The process comprises the following steps: (1) preheated low-grade heavy oil, namely raw oil, enters a zone I of a riser and is in high-temperature short-contact-time high-agent-oil ratio contact with a catalytic cracking catalyst, so as to be subjected to catalytic cracking reaction, and generated oil and gas enter a fractionating tower; (2) a top outlet material of the fractionating tower is a mixture of dry gas, liquefied gas and gasoline, a middle-part outlet material of the fractionating tower is diesel oil, a lower-part outlet material of the fractionating tower is catalyzing wax oil which is relatively difficult to crack, a bottom outlet material of the fractionating tower is oil slurry, the catalyzing wax oil enters a zone II of the riser, and the oil slurry enters a vacuum distillation tower; (3) an upper-part outlet material of the vacuum distillation tower enters the zone II of the riser and is subjected to reaction again, a middle-part outlet material of the vacuum distillation tower enters a hydrogenation device for hydrogenation, and oil slurry at the bottom of the vacuum distillation tower is subjected to treatment by an oil slurry filter and then enters a delayed coking device; (4) a low-carbon-residue easily-cracked material from the hydrogenation device enters the zone I of the riser and is subjected to reaction again. The process has the characteristics that the service life of the catalyst is prolonged, the yield of dry gases and coke is lowered, and meanwhile, the yield of low-carbon olefins and diesel oil is increased.

The invention provides a coal low-temperature carbonization system and method. The system comprises a revolving bed carbonization unit, a raw gas washing unit, a tar trapping unit, a gas convection unit and a gas dry quenching unit, wherein the revolving bed carbonization unit is sequentially connected with the raw gas washing unit, tar trapping unit, gas convection unit and gas dry quenching unit. The system and method shorten the oil-gas retention time in the furnace, reduce the secondary cracking reaction and enhance the tar yield.

The invention discloses a one-stage tandem hydrocracking method, which comprises the following steps that (1) a wax oil raw material and hydrogen are mixed, and the mixture enters a hydrofining reactor and is subjected to a desulfurization, denitrification and aromatic hydrocarbon saturation reaction; (2) the effluent obtained in the step (1) enters a hydrocracking reactor, wherein the hydrocracking reactor comprises first to nth catalyst bed layers along a material direction, n is greater than or equal to 3, and various catalyst bed layers are filled with hydrocracking catalysts with different contents of modified Y molecular sieves; and (3) the effluent of the hydrocracking reactor is subjected to gas-liquid separation, and the liquid phase is fractionated to obtain naphtha, aviation kerosene and diesel oil products. According to the invention, wax oil is used as a raw material, the yield of heavy naphtha with high aromatic potential is increased and the quality of aviation keroseneand diesel oil products is improved by setting a reasonable catalyst grading mode and modulating the catalyst composition and the catalyst structure in grading bed layers.

The invention discloses an oil sludge treatment method which comprises the following steps: the oil sludge enters a drying unit to be dried and dehydrated, and dehydrated oil sludge and a gas-phase material are obtained after dehydration treatment; the dehydrated oil sludge enters a pyrolytic reaction unit to be subjected to a pyrolytic reaction, and pyrolysis gas, oil and coke are obtained afterthe reaction; heat exchange on the gas-phase material is performed to obtain non-condensable gas and condensed water; pyrolysis gas and non-condensable gas enter the combustion unit to be in contact with oxygen-containing atmosphere for a combustion reaction, and hot smoke generated by the reaction serves as a heat source to provide heating heat for the drying unit and the pyrolytic reaction unit.According to the oil sludge reduction, harmlessness and resourceful treatment method, reduction and resourceful utilization of the oil sludge are achieved to the maximum extent, meanwhile, high-valueoil products are recycled, and secondary pollution is avoided in the whole treatment process.

The invention discloses a hydrocracking method, which comprises the following steps: (1) mixing a diesel oil raw material and hydrogen, feeding the mixture into a hydrofining reactor, and carrying outa desulfurization, denitrification and aromatic hydrocarbon saturation reaction; and (2) feeding the effluent obtained in the step (1) into a hydrocracking reactor, wherein the hydrocracking reactorcomprises first to nth catalyst bed layers in a material direction, n is greater than or equal to 3, preferably n is 3 or 4, the first to (n-1)th catalyst bed layers are filled with a hydrocracking catalyst containing a modified Y molecular sieve, and the nth catalyst bed layer is filled with a hydroisomerization catalyst containing a beta or ZSM molecular sieve and other molecular sieves with strong isomerization performance. According to the method, diesel oil is used as a raw material, and through reasonable combination of hydrocracking catalysts with different functions, the yield of heavynaphtha with high aromatic potential is increased, and the low-temperature fluidity of aviation kerosene and diesel oil products is improved.

The invention discloses a method for producing high-octane gasoline. An aromatic hydrocarbon-containing raw material enters a hydrofining reaction zone for a hydrofining reaction, and an obtained effluent and a circulation product enter a hydro-conversion reactor together from the bottom of the reactor and firstly pass through an alkyl transfer catalyst bed; gas-liquid separation is carried out onthe obtained transalkylation effluent in the middle of a reactor, and gas is extracted out of the reactor; the obtained liquid phase passes through a hydro-conversion catalyst bed upwards, and a hydro-conversion reaction is carried out; and a hydro-conversion product and a gas phase extracted from the middle part of the reactor are subjected to separation and fractionating to obtain a gasoline fraction and a diesel fraction. According to the method, gasoline octane number loss caused by excessive hydrogenation can be avoided, meanwhile, good diesel oil blending components are obtained, investment can be better reduced, and the treatment capacity of the device is improved.

The invention relates to a closed type rough cyclone quick separation system carrying multiple-riser reactor for catalytic cracking process and a catalytic cracking method thereof. The reactor provided by the invention comprises risers, a stripping stage, a reacting-settler, rough cyclone separators disposed inside the reacting-settler and cyclone separators disposed on the top of the reacting-settler, wherein outlet ascension pipes of the rough cyclone separators are connected with inlets of the top cyclone separators through an oil gas collecting pipe. As a plurality of independent risers are arranged in the invention, feedstocks of different traits respectively undergo cracking reaction under each appropriate environment according to the requirements of device production schemes and product quality, so as to raise the yield of a target product. As a novel close type rough cyclone quick separation system is adopted on the outlets of the risers in the system, the staying time of cracked oil gas inside a settler is effectively shortened, the coke rate is reduced, and the yield of the target product is raised, therefore guaranteeing the device to operate safely for long periods of time.