INDUSTRIAL PROCESSES OF THERMAL CRACKING OF OIL FRACTIONS:
Process
(different titles)
Raw material Target products
(end products)
Cracking mode
Temperature, ºС Pressure, MPaDuration, s
CRACKING UNDER HIGH PRESSURE
Low-temperature cracking (liquid-phase, primary, visbreaking)Fuel oil – tarBoiler fuels, gas oils440 – 5000,5 – 3,0 120 – 1200
High-temperature cracking (fuel, two-coil, combined)Gas oils, kerosene, fuel oilGasoline, unsaturated hydrocarbons (ethylene, butenes, propylene)500 – 5705 – 7 30 – 180
CRACKING UNDER LOW PRESSURE
Vapour-phase crackingDistillate fractions Unsaturated hydrocarbons, gasoline 530 – 6000,12 – 0,59 0,5 – 5,0
Paraffin crackingParaffin, slack waxes (dewaxing products)α-Olefines (С5 – С20)550 – 6000,12 – 0,60 0,5 – 3,0
Coking (delayed, in drums)Tar, fuel oil, cracking-residue, deasphalted bitumensCoke, motor and boiler fuels420 – 4900,24 – 0,58 (57 – 86) x 103
Thermoform-type cracking (fluidcoking, flexicoking)Tar, fuel oil, heavy oils, native bitumensGasoline, motor and boiler fuels, coke505 – 5600,15 – 0,35 15 – 20
PyrolysisNaphta (straight-run gasoline boiling away below 200 ºС), ethane-butane fraction, gas oilsUnsaturated hydrocarbons, benzene, toluene, aromatic fractions700 – 9000,09 – 0,15 0,1 – 3,0
Steamcracking (Eureka, destructive distillation)Tar, native bitumensGasoline, gas oils, pitch415 – 4300,03 – 0,04 240
ElektrocrackingMethaneEthylene, acetylene1000 – 13000,14 0,01 – 0,1
Plasma-chemical hydrocrackingFuel oil, tar, heavy oilsGasoline, kerosene, diesel fuel440 – 5700,08 – 0,15 0,05 – 0,5


Note! In addition, any fuel oils (heavy high-boiling raw hydrocarbons), heavy hydrocarbon fractions (pyrolysis liquid (synthetic liquid fuel), heavy residues after a distillation process, crude oil, sulfur compounds of oil, used engine oils, heavy residues of crude oil distillation etc.) can serve as a stock material used for processing by plasma-chemical hydrocracking.
AGGREGATE ENERGY EXPENDITURES FOR THE PROCESS:
Cracking method Value, mJ for 1 ton of raw materials
Catalytic cracking1,45
Hydrocracking 2,69
Vapour-phase cracking2,93
Plasma-chemical hydrocracking0,95
ADVANTAGES OF PLASMO-CHEMICAL HYDROCRACKING:
  1. The reactor pressure is close to the atmospheric one.
  2. Gaseous hydrogen is not required; as a hydrogen donator, water is used.
  3. Processing depth of heavy raw hydrocarbons is up to 100%, a heavier fraction is not formed.
  4. Specific energy expenditures are less that energy expenditures during a catalytic cracking.
  5. A reduction of specific energy expenditures is possible by means of matching catalytic and plasma-chemical cracking in one cycle.
  6. During the processing of sulfurous oils, it is possible to obtain pure supfur and hydrogen at the second processing stage by means of a plasma-chemical processing of hydrogen sulfide.
  7. It is possible to manage the composition of hydrocracking products in terms of condensable products-to-hydrocarbons ratio; there is no emission of hydrocarbons to atmosphere – hydrocarbon gas can be used as a hydrogen donator in addition to water.
  8. The plasma-chemical hydrocracking can be used both as an additional and basic equipment for conducting secondary processes at the oil refining units.
  9. Any productivity is possible, from the smallest of 30 liters per hour to the highest productivities (without restrictions).