RU2000101277A - IMPROVED METHOD OF COXING IN A PSEUDEDLATED LAYER - Google Patents

Claims (7)

1. A two-step process for converting starting material, which is a heavy hydrocarbon with a Conradson coke content of at least about 5% by weight, into low-boiling products; moreover, this method includes the following steps:
(a) carry out a partial conversion of the source material to low-boiling products by feeding the source material to the first processing stage, which is carried out in one or more reactors for short-term contact of vapors, moreover, these reactors contain a horizontal movable layer of fluidized hot particles, and upon contact of the source material with hot particles receive products in the vapor phase, and carbon-containing material is deposited on hot particles, and this first stage is carried out
(i) at a temperature of from about 450-700 ^° C .;
(ii) under such conditions that the burden of the presence of solid particles in the reactor and the residence time of the vapors in the reactor are controlled independently, and the residence time of the vapors is less than about 2 s, and the residence time of the solid particles is 5 to 60 s;
(b) then converting said partially converted starting material to low-boiling products in the second processing stage, which is carried out in a coking unit in a fluidized bed that contains a coking reactor and a burner, the coking reactor containing a coking zone, a scrubber zone located above the coking zone and intended for collecting products in the vapor phase, and a desorption zone located below the coking zone and intended to desorb hydrocarbons from ticles extending downwardly from the coking zone, which second stage is performed as follows:
(i) pass the product in the vapor phase, obtained at this first stage, into the scrubber zone in the coking unit in the fluidized bed, where particles entrained in the flow are removed, and the conversion products are collected in the overhead;
(ii) collect from the scrubber zone a stream of light products, the average boiling point of which is about 510 ^o C or lower;
(iii) collect from the scrubber zone the product stream, the average temperature of which is higher than about 510 ^o C;
(iv) pass the particles obtained in the first stage, in which carbon-containing material is deposited, into the coking zone located in the coking unit in the fluidized bed, then into the desorption zone, where hydrocarbons are desorbed by means of the desorbing gas;
(v) pass part of said distilled solid particles from the stripping zone to the burner containing the combustion zone, which includes a layer of fluidized solid particles, and which operates at a temperature exceeding the temperature in the coking zone by 40–200 ^o C to partially burn carbonaceous material on these particles, whereby these particles are heated to a temperature higher than the temperature of the coking zone;
(vi) re-direct at least part of the heated particles from the combustion zone to the reactor for short-term contact, used in the first stage.  2. The method according to claim 1, in which a portion of the heated particles are removed from the burner to the coking zone.  3. The method according to claim 1, in which the residence time in the steam reactor in the first stage is less than about 1 s.  4. The method according to claim 1, in which the source material is a residue of a vacuum oil distillation.  5. The method according to claim 3, in which the residence time in the reactor of solid particles in the first stage is 10 - 30 s.  6. The method according to claim 1, in which the reactor for short-term contact of the vapor used in the first stage, is an installation in which use mechanical means to help the process of fluidization of particles.  7. The method according to claim 6, in which the mechanical means is formed by a set of horizontal screws located inside the specified reactor for short-term contact.