KR810001569B1 - Process for cracking heavy liquid hydrocarbone - Google Patents

Abstract

Heavy liquid hydrocarbons are cracked with steam in the presence of alkali and/or alkali earth metal basic compd.-contg. molter salt mixts.(eg., molten Li2CO3-K2CO3-Na2 CO3 mixts.). At least a quality of molten salt made of mica foam was less than 1-10 parts per heavy liquid hydrocarbons 1 part while a quality of carbon residue was less than 0.03 parts per molten salt wt part.

Description

Pyrolysis of Heavy Liquid Hydrocarbons

1 illustrates an apparatus that can be used to carry out the invention.

The present invention relates to a method for pyrolyzing heavy liquid hydrocarbons containing carbon residues.

The present invention has already proposed a pyrolysis method of a hydrocarbon in Japanese Patent Application No. 97679/1976 (US serial number No. 824, 171 Aug. 12, 1977). This method is suitable for pyrolyzing heavy liquid hydrocarbons, which is characterized by the use of alkali metals, alkaline earth metals and basic compounds of these mixtures in the air phase, and the amount of molten salt is 0.01-1 part by weight per hydrocarbon part.

However, when pyrolyzing heavy liquid hydrocarbons containing a large amount of carbon residues, if the amount of molten salt is small, the molten salt and the heavy liquid hydrocarbons are mixed at low temperatures, and a large amount of water vapor is not supplied, the mixture of molten salts and carbon residues It is easy to attach to the pyrolysis reactor walls due to its consistency, and sometimes the carbon feed inlet can be blocked.

From a commercial point of view, it is desirable to reduce the amount of steam as much as possible, and from a device point of view, severe high temperatures of the molten salt are undesirable. Furthermore, the medium-liquid hydrocarbons should not be preheated above any temperature to prevent thermal degradation before feeding to the pyrolysis semi-bending machine. It is also desirable that the molten salt can be recycled without regeneration.

Therefore, there has been a need for the development of a method capable of satisfying the above conditions in pyrolyzing heavy oil containing a large amount of carbon residues and not being hit by the defects.

It is therefore an object of the present invention to provide a process for pyrolyzing hydrocarbons that does not block near the feed inlet of heavy liquid hydrocarbons.

It is a further object of the present invention to provide a process for pyrolysis of carbohydrates which is extremely low in steam consumption.

It is a further object of the present invention to provide a process for pyrolyzing hydrocarbons which uses significantly reduced amounts of circulating molten salt.

Another object of the present invention is to provide a method for pyrolyzing hydrocarbons, in which molten metal can be reused without reducing carbon.

Another object of the present invention is to remove a hydrocarbon pyrolysis method in which an aqueous gas reacts with water vapor to remove carbon.

It is another object of the present invention to provide a pyrolysis method of hydrocarbon, which can be carried out in a small apparatus using only a small amount of heat.

Another object of the present invention is to provide a method for pyrolyzing hydrocarbons using only a small amount of fruit and without the risk of fire.

It is another object of the present invention to provide a pyrolysis method of hydrocarbons in which carbon and tar phase materials are not deposited in the pyrolysis device and the quenching device.

According to the present invention, there is provided a method for pyrolyzing a heavy liquid hydrocarbon containing a carbon residue, which is constituted under the following conditions (A)-(E).

(A) Pyrolyze in the presence of a molten salt selected from the group consisting of basic compounds of alkali metals, alkaline earth metals and mixtures thereof.

(B) At least part of the molten salt is used in the form of a cloud.

The amount of (C) molten salt is 1 weight part or more and 10 weight part or less per 1 weight part of heavy liquid hydrocarbons.

(D) The amount of carbon residue is 0.03 parts by weight or less per 1 part by weight of the molten salt.

(E) The amount of the water group, the reaction time, the reaction temperature and the amount of the molten salt are adjusted so that the weight ratio of carbon to molten salt after pyrolysis is 0.002 or less.

Referring to the preferred embodiment of the present invention.

Representative heavy liquid hydrocarbons used in the present invention are crude oil, heavy oil, light oil from low pressure distillation, bottom residue from low pressure midstream and the like. These liquid-liquid hydrocarbons contain those which become carbon upon heating such as asphaltenes, resins, and polymers. When the viscosity of the mixture of the solid liquid hydrocarbon and the molten salt becomes significantly high, the supply port of the solid liquid hydrocarbon is blocked. Therefore, it is necessary to lower the viscosity to prevent clogging at the feed inlet. The amount of conradson cardon is thus 0.03 parts by weight or less, preferably 0.005-0.020 parts by weight per 1 part by weight of the molten salt.

If the amount of carbon residue in the heavy liquid hydrocarbon with respect to the molten salt is larger than the upper limit, a mixture of the molten salt and the carbon residue will adhere to the pyrolysis reactor wall. On the contrary, if the amount is too small, the amount of molten salt is unnecessarily large and such a process becomes uneconomical.

If the temperature of the mixture is low, the viscosity rises rapidly.

Therefore, the amount of the molten salt should be 1 part by weight or more and 10 parts by weight or less, more preferably 5 parts by weight or less per 1 part by weight of the liquid hydrocarbon. In the region above the upper limit, the viscosity of the mixture does not significantly decrease, and it is not preferable to use such a large amount of molten salt from an economic point of view. In contrast, in the region below the lower limit, the mixture of the molten salt and the carbon residue becomes viscous and adheres to the pyrolysis reactor wall, and sometimes the supply port of the heavy liquid hydrocarbon is blocked in the presence of a large amount of water vapor.

It is preferable that the molten salt serves to reduce carbon (generated in the pyrolysis reactor) by water gas reaction as much as possible. Therefore, according to the present invention, one of basic compounds such as alkali metal, alkali metal and mixtures thereof is used as the molten salt. In order to prevent the mixture of the molten salt and the carbon residue from becoming viscous and clogging the inlet of the hydrocarbon, a molten salt having a melting point of 450 ° C. or lower is preferred, and particularly preferably a melting point of 400 ° C. or lower.

For example a mixture of Li ₂ CO ₃ (melting point 618 ° C.), Na ₂ CO ₃ (melting point 851 ° C.) and K ₂ CO ₃ (melting point 891 ° C.) is used, preferably an equimolar mixture (eutectic melting point 385 ° C.). As part of these mixtures, sulfides or disulfates can be used.

Steam is present in the reaction system for the purpose of pyrolysis to carry out an aqueous gas reaction. The amount of water vapor is not critically important. However, it is uneconomical to use it in large quantities, and too little is a sufficient water gas reaction. Generally the ratio of water vapor to heavy liquid hydrocarbons is 0.5-5.0, preferably 0.5-2.0.

At least a part of the molten salt is used in the form of a cloud, whereby even a small amount of the molten salt can be in contact with the heavy liquid hydrocarbon so that the water gas reaction can proceed smoothly. The average particle size of the molten salt is generally 300 microns or less, preferably 100 microns or less.

Mistling of the molten salt can be readily prepared by using a Venturi nozzle and passing water vapor.

Other methods of generating clouds include the use of pressurized nozzles such as single ball nozzles, impingement spray valves, spiral spray nozzles, and the like; The use of rotating methods such as rotary disks, rotary fans, rotary sprays, and the like; By the use of a gas-spray spray method such as air or a gas-spray nozzle and the vibration method. Cloudiness is also obtained by dissolving or suspending salts in heavy liquid hydrocarbons or water used as dilution steam and feeding the resulting solution or suspension to the pyrolysis apparatus.

Of these methods of producing clouds, a method is preferred in which at least a portion of the molten salt is converted into a cloud before the molten salt is mixed with the heavy liquid hydrocarbon.

The process of the invention is particularly effective when used for pyrolysis of external heating types. In general, the method of the present invention can be used for pyrolysis of the internal heating type, but in the case of the internal heating type pyrolysis, a large amount of high-temperature heating paste is used to avoid some of the above-mentioned partial cooling of the molten salt, and thus Japanese Patent Application No. . The process of 97679/1976 can be used for pyrolysis of internal heating type.

Pyrolysis is generally carried out at 600-900 ° C., preferably 700-850 ° C., for 0.001-2 seconds, preferably for 0.005-10. Seconds, more preferably for 0.01-0.3 seconds.

The reaction conditions such as the water column, the reaction time, the reaction temperature and the amount of the molten salt are controlled so that the weight ratio of carbon discharged from the pyrolysis reactor to the melt is 0.002 or less, preferably 0.001 or less. The molten salt can thus be reused without undergoing regeneration.

If the amount of carbon is high after completion of the reaction, bubbles of molten salt are generated, and thus, separation from decomposition gas is not performed smoothly.

In order to prevent side reactions, quenching of the reaction mixture withdrawn from the pyrolysis reactor is preferred. The reaction mixture is quenched to a temperature where the molten salt does not solidify. Depending on the respective molten salts it is generally 400-600 ° C., for example. After quenching, the molten salt is separated and recycled, and the pyrolyzed gas is separated and purified into components according to the method used in a typical ethylene production plant.

[Example 1-3 and Comparative Example 1-3]

Referring to the figure, the steam 1 superheated at 750 ° C. by the heater 2 is introduced into the venturi draw 7. The venturi draw is provided with a small transverse hole of 2 mm in diameter. An equimolar mixture of Na ₂ CO ₃ -K ₂ CO ₃ -Li ₂ CO maintained at 750 ° C. through the small lateral hole is supplied as the molten salt to produce a cloud of molten salt.

TABLE 1

The mixture of Minas crude oil (3) (Conradson carbon residue: 2.5% by weight) and water vapor (5) (10% of the total water vapor supply) is heated by a heater (11) to be located underneath the venturidraw and undergo pyrolysis. It is supplied at 300 degreeC to the upper part 9 of the reaction engine 10 of external heating type | mold (outer diameter 21.7mm, inner diameter 14.3mm, length 11m). Minas crude oil (3) and water vapor (5) were heated by heaters (4) and (6), respectively. After pyrolysis, the reaction mixture is quenched to 500 DEG C in the quench section 12, and then the molten salt and the pyrolyzed gas are separated in the separator 13. The separated pyrolysis gas 17 is sent to a refining stage, and the separated molten salt is collected by the drum 14 and transported by a pump 15 driven by an electric motor M, and the heater 19 for reuse. Heated by).

The reaction conditions and the reaction results are shown in Table 1 below.

Claims (1)

Pyrolysed in the presence of a molten salt selected from the group consisting of alkali metals, alkaline earth metals and mixtures thereof, at least a portion of the molten salt being used in the form of a cloud, the amount of molten salt being from 1 part by weight to 1 part by weight of the solid liquid hydrocarbon 10 parts by weight or less, the amount of carbon residues is 0.03 parts by weight or less per 1 part by weight of molten salt, and the amount of water vapor, reaction time, reaction temperature and the amount of molten salt is less than 0.002 by weight of carbon after pyrolysis to the molten salt. A method of pyrolysis of a heavy liquid hydrocarbon containing a carbon residue, characterized in that it is controlled to.

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