RU2293105C1 - Method of heating heavy oil residue in tubular furnace and tubular furnace for realization of this method - Google Patents

Abstract

FIELD: oil production industry; heating oil raw materials in tubular furnaces.

SUBSTANCE: proposed method consists in delivery of initial raw material - heavy oil residue used as fuel which is heated in furnace coil to cracking temperature and is fed to burners at rate no less than 40 m/s. Tubular furnace has box-shaped body with coil tubes, flat wall and burners arranged inside it; terminal tube of coil is laid under hearth and is provided with outlet branch pipes connected with burners and communicated with tubes supplying air, gaseous fuel and steam.

EFFECT: facilitated procedure of preparation of fuel for spraying and burning.

7 cl, 2 dwg, 2 tbl

Description

The invention relates to the refining industry and can be used for heating oil in a tubular furnace.

A known method of heating oil in tubular furnaces using gaseous fuels as fuel for combustion. (NR Entus. Tube furnaces. Publishing house "Chemistry", 1977, p. 78).

Known furnaces for implementing this method, including a housing, a coil placed in the combustion chamber, and burners that can be located both in the hearth and on the front walls (Refinery Handbook edited by G.A. Lastovkin. Leningrad: Chemistry, 1986 g., pp. 304-305).

The known method and device work quite satisfactorily in the presence of gaseous fuel.

A known method of heating heavy petroleum feedstocks in tube furnaces using liquid fuel as fuel for burners - fuel oil (commercial boiler fuel) obtained during oil refining (N.R. Entus. Tube furnaces. Publishing house "Chemistry", 1977 , p. 78-80).

The disadvantage of this method is the need to prepare fuel for combustion, which consists in preheating it to achieve good fluidity and good atomization in the burners of the furnace. At the same time, the required heating temperature must be observed, since when the liquid fuel is underheated, the conditions for its transportation and combustion deteriorate, and overheating can cause intense vaporization and foaming, which leads to pulsation of the torch and can cause a fire.

The closest to the proposed furnace for essential features is a tubular furnace, including a box-shaped body with a coil placed in the combustion chamber and burners located on the front walls at an angle of 45 °. A kiln wall is placed along the axis of the furnace, on which burning torches are directed. The burners are installed with the possibility of supplying them both liquid and gaseous fuels (Catalog. Tube furnaces. - M .: TSINTIHIMNEFTEMASH, 1998, p.11). In this case, when poorly prepared liquid fuel is supplied, the burners do not work well and emergency situations can occur.

Thus, the described method for heating heavy oil feedstocks and a tube furnace for implementing this method require rather complicated preparation of fuel for burning and considerable time and energy for this preparation.

When creating inventions, the task was to simplify the preparation of fuel for burning and reduce the preparation time.

The problem is solved by the proposed method of heating a heavy oil residue in a tubular furnace, comprising supplying pre-prepared fuel to the furnace burners with its subsequent spraying and burning, in which according to the invention, the feedstock is used as a liquid fuel - a heavy oil residue that is heated in a furnace coil to a temperature cracking, and then fed into the burner at a speed of at least 40 m / s.

It is advisable to supply liquid fuel to the burner in an amount of 1-4 wt.% On the feedstock.

At the entrance to the furnace, it is advisable to add water condensate — turbulizer — in the amount of 0.5-2.5 wt.% To the feedstock in heavy oil residue.

The use of feedstock as a liquid fuel for the furnace — a heavy oil residue heated to a cracking temperature and fed to the burners at a speed of at least 40 m / s, eliminates complex and lengthy preparation of liquid fuel for burning, improves reliability, and simplifies the heating of raw materials in the oven.

This problem is also solved by the proposed tubular furnace, including a box-shaped body, inside of which coil pipes are installed along the front walls, a laying wall placed along the axis of the furnace, and burners installed on the front walls, in which according to the invention the end pipe of the coil is located under the hearth of the furnace and is equipped with outlet pipes associated with the burners of the furnace.

It is advisable to inform the outlet pipes with tubes for supplying air, gaseous fuel and water vapor, equipped with flow valves and valves.

Burners can be mounted on front walls at an angle of 45 °.

The end pipe of the coil, equipped with outlet pipes associated with the burners of the furnace, allows you to send part of the heated feedstock - heavy oil residue - to the burners as liquid fuel at a speed necessary for satisfactory atomization of the fuel and its combustion, i.e. in fact, the preparation of liquid fuel for burning takes place directly in the furnace.

The invention is illustrated by drawings, which depict

figure 1 is a tubular furnace in section, a front view;

figure 2 is a section aa in figure 1, where the node "B" is shown schematically.

The method is as follows. At the beginning of the operation, the furnace is started up and heated to the specified parameters using gaseous fuel with a gradual replacement of the starting product, gas oil, with a heavy oil residue with the addition of (0.5-2.5 wt.%) Water condensate - turbulator. The initial oil residue with the quality indicators listed in Table 1 is fed into the furnace tubes, where the stream is heated to 460-500 ° С, as a result, the feedstock evaporates, decomposes (crackes), acquiring new values of the quality indicators (Table 1, column. 5, 6), typical for commercial boiler fuel (Table 1, column 3) used in burners of industrial furnaces. Then the prepared oil residue is already in the form of fuel in the amount of 2% of the feedstock fed to the burner of the furnace.

Table 1
Oil product quality indicators No. Name Boiler fuel GOST 10585-75 grade 100 (prototype) Feedstock at the inlet to the furnace coil Product inlet to furnace burner The viscosity reduction ratio King Visbre (UVB) delayed coking oven (UZK) UVB oven UZK furnace one 2 3 four 5 6 7 8 one 1. Density at 20 ° C, kg / m ³ no more than 1,015 1.018 - - - - 2. Viscosity, ° W, at 80 ° C no more than 16 3000 12 8 250 375 2 1. Density at 20 ° C, kg / m ³ no more than 1,015 1,026 - - - - 2. Viscosity, ° W, at 80 ° C no more than 16 16000 fifteen 10 1066 1600

The table shows that the viscosity of the prepared fuel at the inlet to the burner corresponds to the viscosity of the boiler fuel.

The tube furnace for implementing the proposed method comprises a box-shaped housing 1, in which horizontal pipes of the coil 2 are placed. A wall 3 is located along the axis of the furnace. The coil 2 is in communication with an end pipe 4 located under the hearth of the furnace. The end pipe 4 has outlet pipes 5 connected to the burners 6, placed at an angle of 45 ° on the front walls. To each burner 6 there are tubes 7 for supplying air with an air flow valve 8, tubes 9 for supplying gaseous fuel with a fuel flow valve 10, water supply tubes 11 with shut-off and regulating valves 12, a shut-off valve 13, a fuel consumption valve 14.

The furnace operates as follows. The feedstock, a heavy oil residue, is fed into the pipes of the coil 2. As the flow inside the coil 2 moves due to an increase in its temperature, cracking and evaporation, accompanied by an exponential increase in volume, the flow velocity increases in a similar way and reaches a significant value (40 m / s. ) The flow structure inside the pipe also changes and passes from a homogeneous liquid medium (oil residue, water condensate - turbulizer) to two-phase (gas-vapor - liquid) and then again to single-phase - gas-vapor (soda vol.%) Vapor zhanie 98-99, which enables automatically regulate flow of liquid fuel via valve 14. Table 2 shows the process flow indicators indicating the degree of preparation for spraying fuel and burned.

table 2
Technological and hydrodynamic indicators of the flow of liquid fuel inside the pipe No. Process Technological parameters in the end pipe of the furnace coil The content of the vapor phase, vol.% Flow rate, m / s Flow structure temperature, ° С pressure, MPa one 2 3 four 5 6 7 one Visbreaking oven 490 0.4 98 40 dispersed ring 2 UZK furnace 500 0.5 99 45 dispersed ring

During the cracking process, the high-viscosity heavy raw material is decomposed to form low molecular weight, low-viscosity components (gas, gasoline, light and heavy gas oils), which are the main hydrocarbon components of the prepared fuel. The prepared fuel is taken from the end pipe 4 through the outlet pipe 5 and fed to the burner 6 through the shut-off valve 13 and the fuel consumption valve 14. Air is also supplied to the burner 6 through the pipe 7 through the valve 8. To block and protect the outlet pipes 5 and valves 13 and 14 from coking in them through the locking-regulating valves 12 serves water vapor through the tube 11.

The low viscosity, high temperature (higher than the auto-ignition temperature) and the flow rate of the fuel entering the burner cause good mixing of the fuel with air, a short ignition time and complete combustion of highly dispersed fuel particles in the furnace chamber without the formation of smoke and soot and, therefore, high efficiency of using the prepared fuel.

Thus, the preparation of fuel for combustion takes place directly in the tube furnace, which reduces the preparation time and greatly simplifies the process of heating the feedstock.

Claims (6)

1. A method of heating a heavy oil residue in a tubular furnace, comprising feeding pre-prepared liquid fuel to the furnace burners, followed by spraying and burning it, characterized in that the raw material is used as liquid fuel — a heavy oil residue that is heated in the furnace coil to a temperature cracking, and then fed into the burner at a speed of at least 40 m / s. 2. The method according to claim 1, characterized in that the liquid fuel is fed into the burner in an amount of 1-4 wt.% On the feedstock. 3. The method according to claim 1, characterized in that at the entrance to the furnace in the heavy oil residue add water condensate - turbulator - in an amount of 0.5-2.5 wt.% On the feedstock. 4. A tubular furnace for heating heavy oil residue, including a box-shaped body, inside of which coil pipes are installed along the front walls, a wall laid along the axis of the furnace, and burners installed on the front walls, characterized in that the end pipe of the coil is located under the hearth of the furnace and equipped with outlet pipes associated with the burners. 5. The tube furnace according to claim 4, characterized in that the outlet pipes are in communication with tubes for supplying air, gaseous fuel and water vapor, equipped with flow valves and valves. 6. The tube furnace according to claim 4, characterized in that the burners are installed on the front walls at an angle of 45 °.

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