RU2469068C1 - Coke obtaining method - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: coke obtaining method involves heating of coking raw material in the furnace up to 480-500°C, introduction of inorganic additive to the coking raw material after it is heated in the furnace and further coking of the obtained mixture in the reactor; at that, inorganic additive is added to the coking raw material in the form of a paste-like mixture with hydrocarbon diluter. As inorganic additive there used is CaO or Ca(OH)₂ or CaCO₃. Hydrocarbon diluter represents initial coking raw material or heavy oil residues and other oil products.

EFFECT: method allows enlarging the furnace life and increasing the efficiency of slow coking plant.

4 cl, 1 tbl

Description

The invention relates to the field of oil refining and can be used to obtain delayed coking of coke with a high content of volatile substances, which is used to increase the coking ability of a coal charge in the production of metallurgical coke.

A known method of producing liquid products in a delayed coking unit, comprising heating heavy sulfur-containing petroleum petrochemical products to a coking temperature and coking it in a reactor in the presence of hydrogen in one stage. (RF patent No. 2260616 C2 IPC 7 C10B 55/00). The method aims to reduce the amount of sulfur in the resulting products: gasoline, coke, in light and heavy gas oils.

The disadvantage of this method is to increase the explosion and fire safety at the delayed coking unit using hydrogen as a reagent.

The closest to the proposed method according to the technical essence and the achieved result is a method for producing coke by delayed coking, comprising introducing an inorganic substance into coking raw materials, followed by heating the resulting mixture in a furnace to a temperature of 480-500 ° C and coking in a reactor. (Abyzgildin Yu.M., Syunyaev Z.I., Alekseev P.M. Change in sulfur content during coking of raw materials with inorganic additives. - Coke and Chemistry, 1966, No. 9 p.24-26). The method is aimed at changing the organic form of coke sulphurization to inorganic so that, when using such coke, sulfur converted to an inorganic form having greater thermal stability remains in ash deposits and in sludges when used in non-ferrous and ferrous metallurgy, and is not released into the atmosphere and did not go into the target products: cast iron, metals, alloys, etc.

The disadvantage of this method is the heating of a mixture of coking raw materials with an additive of inorganic origin, which has high coking ability in the furnace coils at coking temperatures of 480-500 ° C, which leads to a reduction in the overhaul run of the furnace and, as a result, a decrease in the productivity of the delayed coking unit.

The present invention is aimed at increasing the turnaround path of the furnace and the productivity of the delayed coking unit while changing the form of sulfur content of coke from organic to inorganic.

This is achieved by the fact that in the method of producing coke, comprising introducing an inorganic additive in the coking feed, heating the latter to a temperature of 475-500 ° C. and coking the resulting mixture in the reactor according to the invention, the inorganic additive is introduced into the coking feed after heating the latter in the furnace in the form paste mixture with a hydrocarbon diluent.

It is advisable to use coking feedstock or heavy oil residues and other petroleum products as a hydrocarbon diluent.

It is advisable to use CaO or Ca (OH) ₂ or CaCO ₃ as an inorganic additive.

It is advisable to feed the inorganic additive into the coking feedstock after heating in an oven in an amount of not more than 15% based on the resulting coke.

The elimination of the ingress of an additive of inorganic origin (crushed solid particles), which has great coking ability, into the coil of the furnace will increase the turnaround path of the latter and, as a result, the productivity of the delayed coking unit with the simultaneous conversion of sulfur of organic origin to inorganic form. A preliminary mixing of an additive of inorganic origin with a hydrocarbon diluent, for example, with part of the same coking feedstock to ensure a paste-like state of the mixture, will facilitate the conditions for its introduction into the transfer pipeline.

The method is as follows.

The coking feedstock, for example tar, is heated in a furnace to a temperature of 475-500 ° C and fed through a transfer pipeline to a coking reactor. At the same time, an additive of inorganic origin — CaO or Ca (OH) ₂ or CaCO ₃ — is pre-mixed with a portion of the same feedstock or other hydrocarbon product in a ratio of 0.5: 1 to 3: 1, preferably 2: 1, in the transfer pipeline. in the form of a paste with a temperature of 100-360 ° C. The resulting raw material mixture with a temperature of 470-485 ° C through a transfer pipeline enters the reactor, while the content of inorganic additives in it, calculated on the resulting coke does not exceed 15%.

As a result of the strong affinity of calcium for sulfur, it converts organic sulfur into an inorganic form during coking, which is characterized by high thermal stability and much less decomposes at high temperatures, turning into ash residues and slags, which reduces emissions of sulfur compounds into the atmosphere and their transition to target products, such as cast iron.

Examples

The table presents comparative data on determining the duration of the operation of the coil of the furnace of the laboratory coking unit until the coke pipe is completely coked at a temperature at the outlet of the furnace of 475-500 ° C and a pressure at the entrance to the furnace of 0.5 MPa when using tar and a mixture of tar and calcium oxide (Cao) in a ratio of 1: 2 according to the prototype and the proposed method.

Table Examples of the method for producing coke Examples Product Name Coil coking time, min 1. Raw materials are heated in the coil of the furnace to a temperature of 500 ° C without mineral additives. Tar (raw coking) - 100% thirty 2. Raw materials are heated in the coil of the furnace to a temperature of 500 ° C together with a mineral additive - prototype. Tar - (coking raw materials) - 98.4% 3 Paste (tar + calcium oxide) - 1.6%, of which: - tar - 0.54%; - calcium oxide - 1.06%. When coking tar with paste in a laboratory reactor, coke is obtained with a content of 3% of a mineral additive based on calcium. 3. The raw materials are heated in the coil of the furnace to a temperature of 500 ° C without mineral additives. The mineral additive is introduced into the heated raw material at the outlet of the furnace coil before being fed to the laboratory reactor Tar - (coking raw materials) - 98.4% (calculated on the overall material balance or 100% calculated on the flow in the furnace coil) thirty Paste mixture (tar + calcium oxide) - 1.6%, of which: coking in the form of a pasty mixture - the proposed method. - tar - 0.54%; - calcium oxide - 1.06%. When coking tar with paste in a laboratory reactor, coke is obtained with a content of 3% of a mineral additive based on calcium.

As can be seen from the table, the introduction of inorganic additives into coking raw materials with subsequent heating of the resulting mixtures to a temperature of 500 ° C (according to the prototype) will lead to a decrease in furnace mileage by 10 times compared to coking without additives. The examples show the technological unacceptability of supplying inorganic additives to a heating furnace together with raw materials.

The introduction of inorganic additives in the coking raw material after the furnace (the proposed method) allows, in comparison with the prototype, to increase the overhaul mileage of the furnace, while ensuring the conversion of organic sulfur to inorganic in the coking process.

Claims (4)

1. The method of producing coke, including the introduction of an inorganic additive in the coking raw material, heating the latter to a temperature of 480-500 ° C and coking the resulting mixture in a reactor, characterized in that the inorganic additive is introduced into the coking raw material after heating in the furnace in the form of a paste-like mixture with hydrocarbon thinner. 2. The method according to claim 1, characterized in that the coking feedstock or heavy oil residues and other petroleum products are used as a hydrocarbon diluent. 3. The method according to claim 1, characterized in that CaO or Ca (OH) ₂ or CaCO _{3 is} used as an inorganic additive. 4. The method according to claim 1, characterized in that the inorganic additive is fed into the coking feedstock after heating in an oven in an amount of not more than 15% based on the resulting coke.