Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G9/00—Thermal non-catalytic cracking, in the absence of hydrogen, of hydrocarbon oils
  • C10G9/02—Thermal non-catalytic cracking, in the absence of hydrogen, of hydrocarbon oils in retorts
  • C10G9/04—Retorts
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J3/00—Processes of utilising sub-atmospheric or super-atmospheric pressure to effect chemical or physical change of matter; Apparatus therefor
  • B01J3/04—Pressure vessels, e.g. autoclaves
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J2219/19—Details relating to the geometry of the reactor
  • B01J2219/194—Details relating to the geometry of the reactor round
  • B01J2219/1941—Details relating to the geometry of the reactor round circular or disk-shaped
  • B01J2219/1946—Details relating to the geometry of the reactor round circular or disk-shaped conical

Definitions

• the reaction zone as a rule consists of an upright, cylindrical pressure vessel, at one end of which the oil feed heated in the cracking furnace is introduced, at the other end being extracted a mixture of liquid and gas to go to further refining steps, for instance to distilling.
• the flow direction in the reaction zone has been either downward from above or upward from below.
• the delay time is very important for thermal cracking.
• the cracking has not time to take place if the delay time is too short. In a case when the delay time is too long, the cracking products begin to react and to form undesired reaction products. As a result, an unstable product Is formed which causes difficulties in the further use of the fuel.
• the aim is therefore a cracking as uniform as possible. If the flow in the pressure vessel serving as reaction zone are non-uniform, the result will be varying delay times.
• the density of the liquid/gas mixture decreases as the mixture flows upward in the pressure vessel. Owing to the hydrostatic pressure differential in the pressure vessel, the density of the gas part also decreases as the mixture flows upward.
• the liquid fractions formed in the cracking reactor have lower density than the feed, which also lowers the density of the liquid/gas mixture. Therefore, the flow velocity is not constant in the usually employed cylindrical reactor with uniform thickness, but accelerates as the mixture flows upward.
• the thermal cracking procedure disclosed in U.S. Patent No. 4.247.387 has a cylindrical vertical pressure vessel serving as reaction zone, and in which a view to preventing refluxes within the reactor have been disposed perforated intermediate bottoms constituting a plurality of mixing sites in the reactor. This aims towards achieving a delay time as uniform as possible for the fraction fed into the zone.
• the use of intermediate plates has its drawbacks. Faulty operation of the reactor may cause the whole reactor to be coked to occlusion. The intermediate bottoms make the coke removal and reactor cleaning inconvenient and expensive.
• the angle of the walls of the reaction zone with reference to the central axis is preferably dimensioned so that the velocity of the liquid/gas mixture will be approximately constant under normal conditions. This is usually achieved when said angle is between 2 and 15 degrees. With angles larger than this, harmful refluxes are produced; similarly if the angle is less than 2 degrees, its effect becomes insignificant.
• the exit from the reaction zone may be shaped to be conical. In that case the angle is selected on the basis of the velocity normally present in the exit tube. The higher the exit velocity, the smaller should the angle be chosen. Angles appropriate in practice vary in the range from 2 to 30 degrees.
• the exit section may also be rounded to conform to an elliptic or spherical surface, or it may be provided with flow guides or equivalent members to prevent refluxes in this region.
• the appropriate temperature is between 410 and 470 degrees and the pressure between 2 and 20 bar.
• the ratio of the average diameter and length of the reaction zone preferably ranges from 1:1 to 1:20.
• Fig. 2 shows on a larger scale the reaction vessel of Fig. 1.
• the feed oil is conducted by the pipe 11 into the furnace 12, where its temperature is elevated to be between 410 and 470 degrees. From the furnace 12, the oil is conducted by the pipe 13 to the reactor 14, where it flows upward from below and exits from the top of the reactor through the pipe 15 to a separate unit (not depicted), in which for instance gas, petrol, light and heavy oil may be separated.
• the average retention time in the reaction zone is between 5 to 100 minutes.
• Fig. 2 shows the reaction vessel 14 of Fig. 1, with the entrance section 16, the actual reaction zone 17 and the conical exit section 18.
• the angle between the walls and the central axes has been denoted with ⁇ , ⁇ and Y .
• the angle ⁇ is larger than the angle ⁇ . It is fully possible that the angles ⁇ and ⁇ are chosen equal, whereby no separate entrance section 16 is noticeable. It is likewise possible, and even advisable, to round the transitions, if any, between the cone angles so that no sharp angulations occur.

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Organic Chemistry (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Engineering & Computer Science (AREA)
• General Chemical & Material Sciences (AREA)
• Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Priority Applications (5)

Applications Claiming Priority (1)

Publications (1)

Family

ID=8515692

Family Applications (1)

Country Status (13)

Cited By (4)

Citations (6)

Family Cites Families (1)

• 1982
  • 1982-06-14 FI FI822120A patent/FI65275C/fi not_active IP Right Cessation
• 1983
  • 1983-05-31 BE BE0/210893A patent/BE896902A/fr not_active IP Right Cessation
  • 1983-05-31 CA CA000429299A patent/CA1203192A/en not_active Expired
  • 1983-06-10 WO PCT/FI1983/000045 patent/WO1984000036A1/en active Application Filing
  • 1983-06-10 NL NL8320166A patent/NL8320166A/nl unknown
  • 1983-06-10 HU HU832277A patent/HU199707B/hu not_active IP Right Cessation
  • 1983-06-10 DE DE19833390050 patent/DE3390050T1/de active Granted
  • 1983-06-10 IT IT21575/83A patent/IT1163502B/it active
  • 1983-06-10 GB GB08401583A patent/GB2133033B/en not_active Expired
  • 1983-06-10 JP JP58501850A patent/JPS59501069A/ja active Granted
  • 1983-06-13 CS CS834232A patent/CS241060B2/cs unknown
  • 1983-06-13 IE IE1380/83A patent/IE55247B1/en unknown
  • 1983-06-14 FR FR8309825A patent/FR2528443B1/fr not_active Expired

Patent Citations (6)

Also Published As

Similar Documents

Legal Events