SU248878A1 - Method for thermocontact cracking - Google Patents

Abstract

A METHOD FOR THERMAL CONTACT CRACKING of heavy oil residues on powdered coke to 540 ^ 0 with subsequent separation of the resulting products, characterized in that, in order to create optimal conditions for all components of the raw material, to increase the yield of the target products, the products obtained during light cracking are divided into heavy and light gas oils, gasoline, propane-butane fraction, dry gas with subsequent thermal contact cracking of each fraction at 540 ~ 700 ^ C in direct-flow reactors.

Description

4 00 00

00 There are several industrial processes and numerous patents on the thermal decomposition (cracking) of petroleum feedstocks. In all cases, wide fractions of the raw material (oil, fuel oil, tar) are cracked, in particular, the mode used cannot be optimal for all incoming components. Some of them are subjected to very deep forms of decomposition for others mode is not sufficiently rigid. To improve thermal contact cracking systems with solid heat carriers, increasing the yield of target products, expanding the range of operational conditions used (high temperatures, low reaction time), a method of selective thermal contact cracking of heavy oil residues is proposed. Depending on the conditions developed in successive stages, obtain liquid and gaseous products for fuel and chemical use. In the proposed method, the raw material from heavy, heavy gas, to heavy residual types of raw material (fuel oil, tar, bitumen, etc.), is directly or mixed with a heavy riser in a reactor with a common layer. The resulting products are divided into rysykl, heavy and light gas oils, gasoline, butane-propane fraction and dry gas, which are further decomposed under appropriate more severe conditions in direct-flow reactors, coke of which enters the reactor with a common layer. supplying a low - octane gasoline to the direct flow reactor to obtain a variant of thermal reforming or pyrolysis of gasoline; when feeding saturated veined gas components (), a variant of thermal pyrolysis is obtained; when heavy gas oil or light gas oil is fed variants of hard or high-temperature cracking with the production of diesel fuel or unsaturated gases, highly aromatic fractions for the production of aromatics and raw materials for the production of carbon black. Specified conditions in successive reactors are provided by their design and temperature in the heater unit. The decomposition products go along with the coke into the main reactor, are separated and separated along with the primary products. Thus, a constant recycle of the desired fractions is ensured. coke high-temperature steps. into the reactor with a common layer. The energy intensity of the selective stages allows to create an installation that is balanced in heat, i.e., without obtaining marketable powdered coke. The method is as follows. The raw material is fed directly to the reactor or to the partial condenser, from which it, together with the heavy liquor, through a series of nozzles is fed into the fluidized bed of the reactor coke. The temperature in the bed is kept within 505-540 ° C. The heat carrier with the coke formed on the surface again, having passed the recoil zone f, enters the coke heater. Air is supplied under the coke heater grill to liquefy, burn, and heat the coke. Flue gases pass through the cyclone system, are vented to the atmosphere or are preliminarily delivered to the recovery boiler. The coke heater is maintained at a temperature sufficient to cover all of the system's heat input, for example, 600-750 ° C and above. Vaporous products from the reactor bed, having passed through single-stage cyclones, come under the partial condenser fender plates, the Target recycle is collected in the battery and returned to the reactor, and all other products come to the separation in the upper part of the partial condenser and fractionation column. the boiling point and above (e.g. 550570 ° C) are taken from the bottom of the column and partly from the partial condenser and sent to the flow reactor. Here, the mode is maintained depending on the direction of decomposition to obtain diesel fractions or highly aromatic liquid products (from 540 to and above) and a residence time of 2–3 s. Products and coke enter the reactor with a common bed, where decomposition stops due to a lower temperature. Middle fractions (of the type of light gas oil) are withdrawn from the main column as components of diesel fuel or, when it is necessary to obtain flavored products, are sent to the second flow reactor, where the high-temperature thermal contact cracking (TCC) mode is maintained (temperature, time 2-5 s ), Gas and gasoline from the top of the co-. The tubes, the condenser and the separator, are directed to gas fractionation and stabilization. It is possible to direct the gasoline of our own, or their mixture, to a direct-flow thermal pyrolysis reactor. This may be a step or a step, when light gas oil is discharged as a component of diesel fuel. The content in the final products of the products of the first stage depends on the coefficient of the retailer at each of the stages. The table presents some experimental data on the yields and characteristics of the decomposition products of distillate fractions obtained during the cracking of tar and fuel oil of UstBalyk oil under conditions of direct selective cracking in a flow reactor without risike at a temperature of 4 and time of about 4 s without taking into account the output of the products at the first stage of the process at the TKK of raw materials in the common layer. . These preliminary data confirm the great possibilities of the process both for the production of fuel products, and especially for unsaturated gas components, aromatics and soot. At the pilot industrial plant TKK with a capacity of 300 tons / day, an alternative was tested for feeding into a direct flow reactor (temperature 600 ° C, time 3 seconds) 20–30% of the raw gas from the heavy gas oil fraction, containing about 25% of the fractions boiling above 500 ° C. At the same time, the output of gas and gasoline on the feedstock increases by 1.5 times, the diesel fraction by 5-8%, heavy gas oil decreases almost 2 times, while the yield of marketable coke practically does not change.

Fractions 200-350 ° C TKK tar

Received; gas

petrol

fraction 200-370 С

the remainder

-.0,

above 370 with coke

Fraction 350-500 ° C

TKK tar

Obtained: gas

petrol

fraction 200-420 ° C

residue above

coke

A mixture of fractions of 200-350 ° C and 350-500 ° C TKK tar in a ratio of 1: 1

Received: fractions

200-450 0

fractions 200-470s

Fractions 350-500 with TCA of fuel oil (when the fuel oil feeds into the partial condenser)

1.4610 118.1 0.97 1.5530 75.7 3.75

3.98

1.5605

0.49

3.76.

1.5684 0.67 1.5700: 18,, 9 Obtained: gas 14.0 gasoline fraction 20.6 Gasoline Arlan 640 3.5 oil 38.8 It was received: gas to C, including gasoline with n. 180 ° C 57.0 residue 180 ° C 4.2

Continuation of table0, 787 1.4438 157.9 0.47 0.9194 1.5156 51.4 2.54 in gas 64.5% of unsaturated hydrocarbons, including ethylene 31%, propylene 23%) 135 (octane, 780 number 77)

Claims (1)

METHOD FOR THERMOCONTACT CRACKING of heavy oil residues on powdered coke up to 540 ° С followed by separation of the products formed, characterized in that, in order to create optimal conditions for all components of the feedstock, to increase the yield of the target products, the products obtained by light cracking are divided into heavy and light gas oils, gasoline, propane butane fraction, dry gas, followed by thermal contact cracking of each fraction at 540-700 ° C in direct-flow reactors.