RU2178447C1 - Plant for thermal cracking of heavy oil residues - Google Patents

Abstract

FIELD: oil refining; processing of heavy petroleum residues in thermal cracking; production of components of motor fuel, diesel fuel and fractions of heavy gas oil-raw material for catalytic cracking. SUBSTANCE: plant includes mixer for petroleum residues and organomineral catalyst, reactor unit with heating furnace and reaction chamber and side reactors, reaction product separator and rectifying column for their separation. Provision is made for separate delivery of vapor and liquid flows to separator for thermal cracking. During delivery of superheated steam, light oil products distillate fractions are separated from heavy cracking residue containing solid phase. Cleaning of distillate fraction flow fed to column for separation from particles of used organomineral catalyst is effected by means of flushing with circulating flow of bottoms product of column. EFFECT: improved operating conditions of technological equipment; improved quality of products. 1 dwg

Description

 The invention relates to the field of oil refining, namely to the processing of heavy oil residues in the process of thermal cracking, and can be used to obtain components of motor fuel, diesel fuel and heavy gas oil fractions - raw materials for catalytic cracking.

 A known installation of thermal cracking of heavy oil residues using the process of thermal cracking of heavy oil residues with the installation in a mixture with a solid organomineral catalyst (OMK). The use of OMK will provide a significant increase in the yield of light oil products - up to 55-65% (RU 2120462, 10.20.98) [1].

 The installation includes a unit for mixing OMK with oil residue, a reactor block consisting of two reaction systems connected in series - a heating furnace - a reactor, a high pressure evaporator (separator), an atmospheric separator of reaction products, and a distillation column for their separation. An intermediate selection of the gas-vapor portion of the thermocracking reaction stream and its separation in a separate cooling and condensation system with the outlet of the gas phase to the fuel network and the condensate to the distillation column is provided. In the atmospheric separator, when superheated water vapor is supplied, light oil products (distillate fractions) are separated from the heavy cracking residue containing a solid phase.

 Distillate fractions are sent to the column. The gasoline and diesel fractions are distinguished on the column, the heavy gas oil fraction - raw materials for catalytic cracking.

 The disadvantage of the installation [1] is the removal, together with the vapors extending from the top of the first reactor and high-pressure separator, of the OMK part and its falling into the system of cooling and condensation apparatus, onto the plates of the upper part of the distillation column with the possibility of their clogging and deterioration of the working conditions of the column, and possible removal of a part of OMK to the fuel network.

 Known combined thermal cracking unit with an oil distillation unit - ELOU-AT, using fuel oil as a thermal cracking raw material - bottoms product of an atmospheric column while using this column for separation of thermal cracking products (RU 2130045, 10.05.99) [2].

 The installation includes a mixer for the bottom product of the atmospheric column with a solid organomineral catalyst (OMK), a disintegrator installed on the outlet line of the mixer, a heating furnace for the reaction mixture, and successively installed reactors (from 2 to 5), the entrance to each of which is in the middle part, and pairs taken from the top of the rectors flow along a common line to the lower part of the atmospheric column. The liquid product from the last reactor is sent to the final separator.

The disadvantage of the described installation [2] is the removal by vapors extending from the top of the reactor of OMK particles into the atmospheric column, which makes it difficult to operate the main apparatuses of the combined installation:
- the ingress of fine solid OMK particles worsens the working conditions of the distillation plates in the column due to the deposition of OMK particles on the plates with the possibility of clogging and complicates the process of separation in the column; the presence in the bottom bottom column of the bottoms of the spent part of OMK increases the total amount of solid component in the feed mixture due to the ballast inactive part of OMK. This complicates the operation of the reactor block and the installation as a whole, in particular due to the possibility of increased coking in the reactors, and thereby worsens the process performance; the final separator of the installation cannot ensure the effective separation of the liquid part of the cracking product, the stable composition and quality of the distillate fractions contained therein and the cracking residue.

Thus, a common drawback of the known installations [1, 2] is the removal from the system with the output flows of OMC particles in the process of isolating the products of the thermocracking reaction, which results in:
- the deterioration of the operating conditions of technological equipment and the associated decrease in the quality of products leaving the installation;
- the inability to ensure the stability of the qualitative and quantitative composition of the cracking residue, which complicates its qualified use.

 These disadvantages are eliminated in the claimed invention. The proposed installation provides a single unit for the collection and isolation of thermocracking products.

 A thermal cracking unit for heavy oil residues in the presence of an organomineral catalyst includes a mixer for heavy oil residues with an organomineral catalyst, a mixture heating furnace, reactors, a separator and an atmospheric separation column for thermal cracking products, the top of the separator being connected to the lower part of the atmospheric column in which the incoming stream is flushed from particles of spent organomineral catalyst by a circulating stream of bottoms of the column.

 The claimed invention can be used in all variants of the technological design of the reaction unit for the thermal cracking of heavy oil residues with OMK, including those described in [1, 2], at any degree of conversion and the number of reaction steps: in an adiabatic reaction system with one or several interstage reactors with or without heating; with an intermediate selection and without an intermediate selection of products according to the reaction steps and introducing all thermal cracking products from the last reactor into the separation in a common stream; in a reactor with heat supply directly in the reaction zone, for example, in the reaction section of a heating furnace; in a combined reaction system comprising reactors of the types described above.

 One of the options for the installation is presented in the drawing.

 The reaction mixture obtained in mixer 1 by mixing the heavy oil residue with OMK is fed through an integrator 2 by pump 3 to furnace 4, in which it is heated to the reaction temperature. The furnace also has a reaction section, where the first step of the thermocracking reaction takes place. The reaction stream passes through the disintegrator 5 and then goes to the middle part of the reactor 6, on top of which a vapor-gas mixture is taken, which is the light part of the thermocracking products, and the liquid product discharged from below passes through the disintegrator 7 and enters the middle part of the reactor 8, in which the thermocracking reaction ends. From the bottom of the reactor 6, the liquid stream is directed to the separator 9. The combined gas and steam stream taken from the top of the reactor 8 is combined with the stream leaving the top of the reactor 6. The combined gas and steam stream from the reactors 6 and 8 also enters the separator 9. Water separator 9 is also supplied. The cracking residue is taken from the bottom of the separator 9. The vapor-gas stream — a mixture of distillate fractions enters the bottom of column 10. The column separates the incoming stream into fractions — gasoline mixed with light gaseous products, diesel and heavy gas oil — feedstock for catalytic cracking. At the bottom of the column, the incoming steam stream is washed from the OMK solid particles removed from the separator 9. This prevents OMK particles from entering the distillation plates of the column 10. The washing is carried out by a circulating stream of heavy gas oil. The circulation is carried out by the pump 11, which also pumps out the heavy gas oil fraction withdrawn from the column 10.

 The mixture of the gasoline fraction with light gaseous products through a condenser 12 enters the separator tank 13, where the gasoline fraction is separated from the light gaseous products sent to the fuel network.

Claims (1)

 A thermal cracking unit for heavy oil residues in the presence of an organomineral catalyst, including a raw material mixer with an organomineral catalyst, a furnace for heating the mixture with a reaction section, disintegrators, remote reactors, a separator and an atmospheric column for the separation of thermocracking products, characterized in that combined-gas flows are selected separately to the separator on top of the reactors along the process steps and combined in one line, and liquid cracking products from the last reactor, from the bottom of the separator the cracking residue is obtained using superheated water vapor, the top of the separator is connected to the bottom of the atmospheric column, in which the incoming stream is washed from particles of spent organomineral catalyst by a circulating stream of bottom product of the atmospheric column.