RU2712663C1 - Method and installation of coking chambers heating - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: group of inventions relates to oil processing, namely to methods of coking oil residues and devices for producing petroleum coke. Method of coking chamber heating includes preliminary heating with the help of water vapor and final heating by means of liquid hot distillate product, supplied from rectification column to upper part of coking chamber and representing heavy gasoil, heated to temperature of 320–340 °C. To implement the claimed method, an installation is used, which includes coking chambers, a system of hot heat carrier supply pipelines from the rectification column to the upper part of the coking chamber, spraying nozzles for supply of distillate product, system of pipelines for pumping of cold heat carrier, reservoir for collection of cold heat carrier, pump for pumping of heat carrier and system of pipelines for return of heat carrier to rectification column.

EFFECT: higher efficiency of delayed coking unit with simultaneous reduction of heat energy consumption during coke production.

2 cl, 1 dwg, 1 tbl

Description

The group of inventions relates to oil refining, and in particular to methods of delayed coking of oil residues and devices for producing petroleum coke.

A feature of the delayed coking process in unheated coke oven chambers is the need to preheat the inoperative coking chamber to a temperature of 320 - 360 ° C before feeding the processed raw materials into it, for which the chamber walls are heated with oil product vapors coming from the working chamber, and vaporization of oil products and their transition to the liquid phase.

A number of methods for preheating coking chambers are known.

A known method of heating a delayed coking chamber, comprising supplying to the inoperative coking chamber first a primary heating agent — water vapor, and then a secondary heating agent — distillate steam from the working coking chamber, with subsequent removal of the heating products to a scrubber vessel and, further, to a distillation column (book: N.T. Porodenko, B.I. Bronds "Production and processing of petroleum coke." M.: "Chemistry", 1986, p. 60-63).

The disadvantage of this method is that during the heating of the coking chamber, a mixture of liquid distillate products is formed, which consists of water and light and heavy gas oil fractions (heating products), which does not have a sufficiently high temperature for further processing, which leads to the need for additional heating before feeding into the distillation column, while the products of heating in the distillation column are mixed with raw materials, and therefore there is a decrease in the productivity of the plant for the production of Left products.

Also known is a method of heating a delayed coking chamber, comprising supplying to the reactor a primary heating agent — water vapor and a secondary agent — distillate steam from the coking chamber, followed by removal of the heating products to a tank, from which the vapor phase goes into a purge tank or distillation column, and the liquid phase is pumped into substandard oil product (publication: G.G. Valyavin, N.I. Vetoshkin, I.G. Musin “Analysis of the schemes for capturing products released during chamber heating, steaming and cooling of coke, development of measures to reduce emissions into the environment "OJSC Novo-Ufa Refinery", the magazine "Oil Refining and Petrochemical Industry", vol. 9, M., TsNIITEneftehim, 1998, pp. 71-75).

The disadvantage of this method is that in the process of heating the coking chamber, a mixture of liquid distillate products is also formed, which consists of water and fractions of light and heavy gas oil (heating products). With this heating method, the productivity of producing target products is also reduced, since the quantitative and qualitative composition of the resulting mixture changes over time, which greatly complicates its separation and further processing, and therefore it should only be disposed of as a substandard oil product.

The closest in technical essence and the achieved result to the claimed method is a method for producing petroleum coke delayed coking of oil residues according to the patent for the invention of the Russian Federation No. 2433159 (publ. 10.11.2011), in accordance with which the coking chamber is heated first with water vapor, then coking vapor supplied to the upper part of the coking chamber and additional heating of the coking chamber with a coolant - heavy coking gas oil, heating of the coking feedstock and secondary raw materials, heating of the coolant I - heavy coking gas oil and the supply of secondary raw materials and coolant to the lower part of the coking chamber, while the coolant - heavy coking gas oil is heated to a temperature of 400 - 420 ° C and fed with secondary raw materials to the lower part of the coking chamber in separate streams with the latter supplying through an additional column moreover, the aforementioned coolant is also supplied to the middle and upper parts of the coking chamber when filling the latter at 1/3 and 2/3 of its height, respectively, with additional heating of the coking chamber after under Water vapor is carried out jointly with the heat transfer medium and the coking vapors, and the heat transfer agent is supplied to the middle part of the coking chamber during heating.

The specified method allows to obtain petroleum coke with an increased yield of volatile substances due to the regulation of the temperature regime of coking along the height of the coking chamber with a simultaneous increase in the duration of the reaction equipment. However, this method has the disadvantage that it is designed to produce coke with a high content of volatile substances, and cannot be used for the production of other types of coke. In this case, to heat the coolant, it is necessary to spend an additional amount of fuel, and also since the coolant is supplied to the middle part of the coking chamber, which does not ensure its uniform heating, and the resulting mixture of liquid distillate products, which consists of water and light and heavy gas oil fractions, is also the heating products It has a low temperature, and additional energy is required to heat it before being discharged into the distillation column. At the same time, the heating products in the distillation column are also mixed with raw materials, and therefore, during the heating of the coking chambers, the productivity of the plant for the production of target products decreases.

Thus, a common drawback of all of the above methods, including the prototype, as well as the problem to be solved, is that when the coking chambers are heated by using distillate vapors, a mixture of liquid distillate products consisting of water and fractions of light and heavy gas oil is formed, which has a low temperature and therefore additional thermal energy is required to heat it before further processing, while the heating products are mixed with raw materials, which leads to a decrease in the productivity of the installation by launching targeted products.

The technical result of the claimed group of inventions is to increase the productivity of the delayed coking unit while reducing the consumption of thermal energy when producing coke.

The claimed technical result is achieved due to the fact that the heating of the coking chambers is carried out using coking products coming out of the distillation column in a manner comprising the following steps:

1. In the lower part of the coking chamber previously freed from coke (with the lower and upper hatches of the chamber closed), water vapor is supplied at a pressure of 8–12 kgf / cm ² , which displaces oxygen from the internal space of the coking chamber and heats its walls to a temperature of 80–100 ° C, after which the steam supply is stopped;

2. Next, a hot distillate product heated to a temperature of 320 - 340 ° C, which is a heavy gas oil discharged from a distillation column, is fed into the upper part of the coking chamber through a spray nozzle. Under the influence of gravity, the distillate product flows down the inner surface of the coking chamber, and thermal energy is transferred from the hot distillate product to the chamber wall, and the distillate product is cooled;

3. After the cooled distillate product accumulates in the lower part of the coking chamber, it flows through the pipeline into the purge tank, and then is pumped to the distillation column irrigation pipeline or is selected as the target product from the installation;

4. After the coking chamber warming to a temperature of 300 - 320 ^{° C} it is directed in the raw material for carbonization.

Thus, in accordance with the claimed method, in the process of heating the coking chamber, a mixture of heating products is not formed, and the composition of the secondary heating agent of the distillation product does not change, which means that there is no need for additional heating of the heating products for re-separation in the distillation column, while since the secondary heating agent is not mixed with the primary raw material, the productivity of the installation does not decrease.

To implement the inventive method, a coking chamber heating apparatus is used, including coking chambers, a furnace for heating the heat carrier (heating agent), a piping system for supplying heat to the middle part of the coking chamber, while spray nozzles are installed in the upper part of the coking chambers to supply the distillate product, which are connected using a distillation column pipeline.

The inventive installation for heating the coking chambers is shown in the figure, and contains: a pipeline (1), through which the primary raw material enters the heat exchanger (2), which serves to preheat the primary raw material, and connected via a pipeline (3) to a distillation column (4), which, in turn, is connected to a pump (5) for pumping out raw materials and feeding them to a fire heating furnace (6), which is connected via pipelines (7) to coking chambers (8) and (9), in the upper part of which are installed spray nozzles (10) (11), while cam Coking rods (8) and (9) are connected via a hot distillate product supply pipe (13) equipped with a flow meter (14) and a regulator valve (15), to a circulation irrigation pipe (3) and then to a distillation column (4), and The coking chamber heating unit also includes a steam supply pipe (12) and a purge tank (16) connected to the pump (17) through a pipe (18) for pumping cold distillation product into the circulation irrigation pipe (3) or the heavy gas oil pumping pipe wki (19).

The inventive installation operates as follows.

Through the pipeline (1), the primary raw material enters the heat exchanger (2), where it is heated using hot heavy gas oil and enters through the irrigation pipeline (3) to the bottom of the distillation column (4). Then, from the bottom part of the distillation column (4), the raw material is pumped out using a pump (5) and fed to the fire heating furnace (6), and then, after heating, the raw material enters through pipelines (7) into one of the coking chambers (8) or ( 9).

In the coking chambers, a chemical process occurs, as a result of which coke is formed from the primary raw material and distillate vapors are released, while the formed coke accumulates in the lower part of the coking chambers (8) or (9), and the distillate vapors enter the distillation column for separation (4) .

Coking chambers operate in pairs: when the coking process is in progress in the first chamber and coke is filled with it, operations are carried out in the second chamber to prepare for filling (cooling coke, releasing coke, heating the chamber). After filling the first chamber, the feed stream is transferred to the second chamber and the process is repeated . The time for filling each chamber with coke is from 16 to 28 hours.

The coking chambers are heated as follows: in the lower part of one of the coking chambers (8) or (9) previously exempted from coke, a primary heating agent is supplied — water vapor through water supply pipelines (12) at a pressure of 8 - 12 kgf / cm ² , which displaces oxygen from the inner space of the coking chamber and after heating it to a temperature of 80 - 120 ° С, the supply of water vapor to it is stopped, after which, for its further heating, it is supplied through the spray nozzle (10) or (11) through the pipeline (13) from distillation to Lonna (4) hot distillate product is heated to a temperature of 320 - 340 ° C. The control and regulation of the flow rate of the hot distillate product is carried out using a flow meter (14) and a regulator valve (15).

The distillate product, flowing down the inner surface of the coking chamber, heats its walls of the coking chamber.

The cooled distillate product accumulates in the lower part of the coking chamber (8) or (9), flows through a pipeline into a purge tank (16), and then is pumped by a pump (17) through a pipeline (18) to the distillation column irrigation pipe (3) or a pumping pipeline (19) heavy gas oil from the installation.

After warming the coking chamber to a temperature of 300 - 320 ^{° C} it is directed in the raw material for carbonization. The duration of the heating process of the coking chamber is 4 to 5 hours.

Thus, the claimed technical result is achieved, namely, the productivity of the delayed coking unit is increased, the yield of volatiles during coke production is increased, while the consumption of thermal energy is reduced.

The effectiveness of the proposed method is confirmed by calculations.

For the calculation, the formula for calculating the amount of required heat was used:

Q = C x M x (T ₂ -T ₁ ) [1], where:

Q is the amount of heat, kJ;

C - specific heat capacity kJ / kg, ° C;

M - weight, kg;

T ₁ - temperature at the beginning of heating, ° C;

T ₂ - temperature at the end of heating, ° C.

1. Using the formula [1], we calculate the amount of heat Q _chamber necessary for heating the coking chamber. accepting the following conditions:

Specific heat of steel C_to= 0.5 kgJ / kg, ° C;

The average mass of coking chambers used in delayed coking plants is M = 209,000 kg;

The temperature of the coking chamber at the beginning of heating T ₁ = 100 ° C;

The temperature of the coking chamber at the end of heating T ₂ = 320 ° C.

Thus: Q _camera = 0.5 x 209 000 x (320-100) = 22 990 MJ.

Including heat loss (10%): Q _camera = 1.1 x 22990 = 25,289 MJ.

2. Using the formula [1], we also calculate the amount of heat Q of _{gas oil} contained in a hot distillation product (gas oil), taking the following conditions:

To do this, we determine the mass of gas oil supplied to heat the chamber.

M _{gas oil} = V x F, where:

V - warm-up time, hour;

F is the average gas oil consumption, kg / h.

Accepted for calculation:

Duration of heating V = 5 hours;

The average consumption of superheavy gas oil is F = 60,000 kg / h.

Thus: M _{gas oil} = 5 x 60,000 = 300,000 kg.

Average heat capacity of gas oil C_g = 2.5 kJ / kg ° C.

The temperature of the gas oil before feeding into the chamber T ₂ = 342 ° C.

The gas oil temperature after heating the chamber T ₁ = 250 ° C.

We determine the amount of heat according to the formula [1]:

Q _{gas oil} = 2.5 x 300 000 x (340-250) = 67 500 MJ.

From the calculations it is seen that the amount of heat of gas oil is sufficient to heat the chamber to 320 ° C:

Q _chamber = 25,289 MJ < _{gas oil} = 67,500 MJ.

3. Since the temperature of the chamber changes during heating, it is therefore also necessary to change the amount of gas oil supplied to the chamber.

It was made the calculation amount gasoil F _{gas oil} required for heating the chamber to 320 ^{° C} taking into account the temperature changes by the formula [2].

[2],

[2]

Where:

M _{to - the} mass of the coking chamber, kg

With _{to - the} heat capacity of steel, kJ / kg, ° C;

Т _{1к -} temperature, coking chamber walls at the beginning of heating, ° С;

T _2k - temperature, coking chamber walls at the end of heating, ° C;

C _g is the average heat capacity of gas oil, kJ / kg, ° C;

T _{2g -} gas oil temperature before feeding into the coking chamber, ° С;

T _{1g - the} temperature of gas oil after heating the coking chamber, ° C.

Data on the calculation of the amount of gas oil required for feeding into the coking chamber are presented in Table 1.

The table shows that, taking into account existing restrictions on the rate of heating of coke oven chambers (the rate of consumption of a hot distillation product is gas oil, on average, equal to 60,000 kg / h and the rate of heating of the coking chamber is not more than 60 ° C / h) when using a hot distillation product ( gas oil) provides effective heating of the entire volume of the coking chamber.

Thus, the calculations confirm the possibility of achieving the claimed technical result, which consists in increasing the productivity of the delayed coking unit, producing coke with an increased yield of volatile substances and, while reducing thermal energy consumption.

Table 1

Continue
stage duration, hour The temperature of the wall of the coking chamber T _1k ,
° C The temperature of the wall of the coking chamber T _2k , ° C The amount of heat required for heating, taking into account losses, MJ The gas oil temperature before feeding into the coking chamber T _2g , ° C The temperature of gas oil after heating the coking chamber T _1g , ° C _Gas oil consumption F _GASOIL , kg / h 1 100 160 6,897 340 200 19,705 2 160 220 6,897 340 250 30,653 3 220 280 6,897 340 300 68 970 4 290 310 2,299 340 320 45 980

Claims (2)

1. The method of heating the coking chamber, including preheating with water vapor and final heating with distillate vapor, characterized in that the final heating of the chamber is carried out using a liquid hot distillate product coming from the distillation column into the upper part of the coking chamber and is a heavy gas oil heated to a temperature of 320-340 ° C. 2. Installation of heating of the coking chamber, including coking chambers, a furnace for heating the heat carrier - a heating agent, a piping system for supplying heat to the middle part of the coking chamber, characterized in that spray nozzles are installed in the upper part of the coking chambers for supplying a distillate product, which are connected by pipeline with distillation column.

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