JP2002147746A - Heating equipment for high-viscosity oil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide heating equipment for high-viscosity oil, which obviates the necessity for substitution of a low-viscosity oil for a high-viscosity oil in the case of a boiler shutoff for a long period of time, and enables the boiler to start rapidly a stable combustion by receiving a supply of a high-viscosity oil. SOLUTION: A control temperature-selector 10 switches over a control temperature of a temperature control valve 8 to a low side at a time when a closing-signal is issued to a steam-shutoff valve 3, while it switches to a high side, at the time when an opening-signal is issued to the valve 3. Thus, the steam-shutoff valve 3 is operated at a boiler start-up time to heat the high-viscosity oil to an elevated temperature by the high-pressure steam supplied from a high-pressure steam-supply pipe T2, and the temperature is detected by a thermometer 17. When the temperature has reached at least an adequate value, a circulation open/close valve 18 is automatically closed, and a burner open/close valve 20 is opened to supply the high viscosity oil to the burner through a fuel supply pipe T7. During an operation shutoff, the valve 3 is closed, a low-pressure steam is supplied to a heater 1 from a steam supply pipe T4 to heat the high-viscosity oil at a low temperature, and the steam is refluxed through the valve 18 and a circulation pipe T6 to a tank 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-viscosity oil heating apparatus used when a high-viscosity oil such as a vacuum residue produced as an intermediate product in a petroleum refining process is consumed as a fuel for a boiler or the like.

[0002]

2. Description of the Related Art Vacuum residue produced as an intermediate product in a vacuum distillation column in an indirect desulfurization step in a petroleum refining process is partially used as asphalt or coke for civil engineering and steelmaking. The portion has been used as a synthetic heavy oil mixed with light oil. In recent years, the demand for asphalt, coke and synthetic heavy oil, which are these by-products, has been declining.
It has been used as a heat source for direct combustion in boilers and the like.

[0003] The viscosity of vacuum residue is very high. Conventional C
For heavy oil, the appropriate temperature for spraying the burner is 100 to 120 ° C., but at this temperature, the kinematic viscosity of the vacuum residue oil is 1000
mm ² / s. Suitable kinematic viscosities for burner spraying are less than about 30 mm ² / s, for which the vacuum residue must be heated to a high temperature of 210-230 ° C. If it can be heated to a temperature at which such an appropriate kinematic viscosity for burner spraying can be obtained, it can be stably supplied and burned in the same manner as ordinary heavy C oil. Conventional heating of heavy fuel oil C is performed by steam generated and usable in the plant. In the case of C heavy oil, for example, 1.0
MPa, a low-pressure steam with a saturation temperature of about 180 ° C. may be used, but in order to heat a high-viscosity oil such as the above-described reduced-pressure residue oil to 210 to 230 ° C., which is an appropriate viscosity for use in burner spraying, for example, as a heating steam source, High-pressure steam of 4.0 MPa and a saturation temperature of 250 ° C. must be used. The low-pressure steam is supplied from equipment other than the boiler or from the boiler. However, the high-pressure steam cannot be supplied without generating high-pressure steam unless the boiler is operated.

FIG. 3 is a system diagram of a conventional high-viscosity oil heating device. High viscosity oil from the tank 13 to the high-viscosity oil is stored is pressurized by the fuel supply pump 14, it is supplied to the heater 1 via the oil supply pipe T _1. To the heater 1 is high-pressure steam supply pipe T ₂ steam shut-off valve 3, the high pressure steam sent from the boiler (not shown) through a steam pressure control valve 4 and the temperature control valve 8 is supplied as a heating source. High pressure steam led to the heater 1 is recovered from the discharge pipe T ₃ through Kokiben 11 inside is high-viscosity oil and the heat exchange thereof. Temperature controller 9 adjusts the heating amount of the heater 1 by detecting the temperature of the high-viscosity oil flowing through the oil delivery pipe T ₅ immediately after the heater 1 by controlling the opening of the temperature control valve 8. Circulation pipe T ₆ circulation-off valve 18 interposed are is open until the temperature of the high-viscosity oil thermometer 17 detects is equal to or greater than a proper heating temperature, tank 1 a high viscosity oil
Reflux to 3. On the other hand, the burner on-off valve 20 interposed in the fuel supply pipe T ₇ which is connected to the oil delivery pipe T ₅ between the circulation pipe T _6, the temperature of the high-viscosity oil thermometer 17 detects the proper heating temperature or higher and It is closed until it becomes. When the temperature of the high-viscosity oil is equal to or higher than a proper heating temperature, the circulation-off valve 18 is closed, because the burner off valve 20 is opened, high-viscosity oil sent through the oil delivery pipe T ₅ is through the burner on-off valve 20 And supplied to a burner (not shown).

The thermometer 17 is connected to the temperature controller 9
While but provided immediately after the heater 1 for the purpose of controlling the heating temperature in the heater 1, in general, longer lengths of pipe, such as oil delivery pipe T _5, the climatic conditions extent to be cooled on the way since depends like, it is provided to measure the temperature of the high-viscosity oil branch near to possible fuel feed pipe T _7. When the boiler is stopped for a long period of time, the high-viscosity oil may be solidified in the oil pipe. Therefore, the boiler is stopped after replacing it with low-viscosity oil. First, since heating with high-pressure steam becomes unnecessary, the steam shutoff valve 3 is closed and the tank 13 is closed.
Feed pump 1 to stop the supply of high viscosity oil from
4 is also stopped. Next, low-viscosity oil is supplied from the low viscosity oil inlet tube T ₈ via a check valve 23 to the oil supply pipe T _1.
At this time, the oil supply pipe T ₁ , the oil delivery pipe T ₅ , and the fuel supply pipe T ₇
The burner on-off valve 20 remains open to discharge the high-viscosity oil remaining in the burner. Therefore, the supplied low-viscosity oil is supplied to the burner section via the burner opening / closing valve 20. The thermometer 17 detects the temperature of the low-viscosity oil, and since the temperature is lower than the appropriate heating temperature of the high-viscosity oil, the circulation on-off valve 18 opens and the burner on-off valve 20 closes. Thereby, the oil supply pipe T ₁ , the oil delivery pipe T ₅ , the circulation pipe T _6, and the fuel supply pipe T
All fuel oils in ₇ are replaced from high viscosity oils to low viscosity oils.

[0006]

The heating device for high-viscosity oil is heated by only one system of high-pressure steam. When the boiler is stopped, there is no problem if the boiler is stopped for a short period of about one day. However, if the suspension period is longer, there is a possibility that the high-viscosity oil solidifies in the oil pipe.
High viscosity oil in oil piping must be replaced with low viscosity oil. After such replacement is performed, when the boiler is started and high-pressure steam is supplied, the low-viscosity oil is heated at a high temperature in the piping of the heating device, and the low-viscosity oil in the oil piping is heated in the oil piping. Low-boiling components are gasified, and they move in the oil piping and are led to the burner, where intermittent jetting with the oil causes so-called breathing combustion, which makes combustion unstable. is there. In addition, since it takes a long time to completely switch the combustion oil to the high-viscosity oil, a large amount of expensive low-viscosity oil is consumed.

An object of the present invention is to provide a high-viscosity oil heating apparatus which does not require replacement of high-viscosity oil with low-viscosity oil when the boiler is shut down for a long period of time, and which can promptly shift to stable combustion of high-viscosity oil at startup. To provide.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is to supply low pressure steam to a heater together with high pressure steam. Preferably, the high pressure steam is supplied to the heater when the boiler is operating. When the boiler is stopped, supply of high-pressure steam to the heater is stopped, and low-pressure steam is supplied to the heater, and the steam supply path to the heater is connected to the fuel supply path from the heater. Temperature control means for adjusting the steam flow rate based on the temperature of the circulating fuel is provided.When the boiler is stopped, the adjustment temperature of the temperature control means is set low, and when the boiler is operating, the adjustment temperature of the temperature control means is set high. An opening / closing valve is interposed in the high-pressure steam introduction path, and the opening / closing operation of the opening / closing valve is synchronized with the setting of the adjustment temperature of the temperature control means when the boiler is started / stopped.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a system diagram of a high-viscosity oil heating device according to an embodiment of the present invention. In the figure, the pressure control valve is interposed in the downstream of the steam shut-off valve 3 4, 5 are interposed downstream of the pressure control valve 4 of the high-pressure steam supply pipe T _2, based on the vapor pressure of the detected tube pressure controller to maintain a predetermined pressure by controlling the opening degree of the pressure control valve 4, 7 reverse to prevent the high-pressure steam fed from the high-pressure steam supply pipe T ₂ from flowing back to the steam supply pipe T ₄ side of the low pressure The stop valve 10 is connected to the steam cutoff valve 3, the temperature control valve (functionally having a flow rate adjusting function) 8 and the temperature controller 9, and the control temperature of the temperature control valve 8 is controlled by the open / close signal of the steam cutoff valve 3. Control temperature switch for switching, 1
1 is passed through a water only the discharge tube T ₃ side to prevent the passage of steam Kokiben (trap). The same reference numerals are given to portions which are the same as or can be regarded as the same as those in the conventional example, and redundant description will be omitted.

[0010] In the present embodiment adapted to a low-pressure steam fed from the high pressure steam and the steam supply pipe T ₄ were fed from the high-pressure steam supply pipe T ₂ are merged in front of the temperature control valve 8. The control temperature switch 10 controls the temperature of the temperature control valve 8 when the close signal is output to the steam shutoff valve 3 and the control temperature of the temperature control valve 8 is low when the open signal is output to the steam shutoff valve 3. Switch so that is higher. Since boiler during stop of the steam shut-off valve 3 is closed, the heater 1 is supplied with low-pressure steam from the steam supply pipe T _4, the low-temperature high-viscosity oil supplied through the oil supply pipe T ₁ Heat. At this time, since the circulation opening and closing valve 18 is opened, high-viscosity oil flows back to the tank 13 through the circulation pipe T _6. As a result, the high-viscosity oil is maintained at a uniform predetermined temperature in the oil pipe, and is prevented from solidifying.

[0011] open the steam shut-off valve 3 at the time of startup, the high-pressure steam temperature control valve which is fed from the high-pressure steam supply pipe T ₂ 8
It joins the low pressure steam from the steam supply pipe T ₄ at the front. The high viscosity oil pressure steam is supplied through the oil supply pipe T ₁ and high-temperature heating, the temperature is detected thermometer 17, when it becomes more than a proper heating temperature, automatically circulating off valve 18
Together closes, because the burner off valve 20 is opened, high-viscosity oil is not recirculated to the tank 13, it is supplied to the burner through a fuel supply pipe T _7.

Next, the operating conditions of the actual high-viscosity oil will be described. FIG. 2 is a characteristic diagram in which the temperature characteristic of the kinematic viscosity coefficient of the actual high-viscosity oil is logarithmically displayed. As is clear from the figure, the kinematic viscosity coefficient of the high-viscosity oil is 1000 mm ² / max at 120 ° C.
The temperature at which the kinematic viscosity coefficient becomes 30 mm ² / s or less, which is the appropriate spray viscosity of the burner, is about 210 ° C. When heating high-viscosity oil, common steam in the plant (1.0 MPa, saturation temperature 184 ° C) as low-pressure steam while the boiler is stopped
During operation of the boiler, dedicated high-pressure steam supplied from the boiler as high-pressure steam (4.0 MPa, saturation temperature 252)
° C) was used. Therefore, while the boiler is stopped, as described above, the high-viscosity oil is maintained at 150 ° C. to 170 ° C. by using low-pressure steam to secure fluidity, and at the time of startup, high-pressure steam is supplied to the heater 1. Within one hour, the temperature of the high-viscosity oil was raised to 210 ° C., which is the temperature at which the burner has a proper spray viscosity.

[0013]

As described above, according to the first aspect of the present invention, since the low-pressure steam is supplied to the heater together with the high-pressure steam, the low-pressure steam is supplied even when the high-pressure steam is not supplied to the heater. Therefore, it is not necessary to replace the high-viscosity oil with the low-viscosity oil when the boiler is shut down for a long period of time, and it is possible to quickly shift to stable combustion of the high-viscosity oil at the time of startup. According to the second aspect of the invention, when the boiler is operated, high-pressure steam is supplied to the heater, and when the boiler is stopped, supply of high-pressure steam is stopped, and low-pressure steam is supplied to the heater. When the boiler is stopped, the high-viscosity oil can be kept in a low-temperature heating state with low-pressure steam.

According to the third aspect of the present invention, the steam supply path to the heater is provided with temperature control means for adjusting the steam flow rate based on the temperature of the fuel flowing through the fuel supply path from the heater. When stopped, lower the temperature of the temperature control means.
During the operation of the boiler, the adjustment temperature of the temperature control means is set high, so that the heating temperature of the heater can be kept constant. According to the fourth aspect of the present invention, the on-off valve is interposed in the high-pressure steam introduction path, and the opening and closing operation of the on-off valve is synchronized with the setting of the adjustment temperature of the temperature control means when the boiler is started and stopped. The heating temperature of the heater can be maintained constant only by opening and closing the on-off valve in synchronization with the start / stop of the boiler.

[Brief description of the drawings]

FIG. 1 is a system diagram of a high-viscosity oil heating device according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram in which temperature characteristics of a kinematic viscosity coefficient of a high-viscosity oil are logarithmically displayed.

FIG. 3 is a system diagram of a conventional high-viscosity oil heating device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heater 3 Steam cutoff valve 4 Pressure control valve 5 Pressure controller 8 Temperature control valve 9 Temperature controller 10 Control temperature switch 11 Coagulation valve (trap) 13 Tank 14 Fuel supply pump 17 Thermometer 18 Circulation on-off valve 20 Burner On-off valve

Claims (4)

[Claims] 1. A high-viscosity oil supplied from a tank is heated by a heater that exchanges heat with high-pressure steam. When the temperature of the high-viscosity oil flowing out is lower than an appropriate heating temperature, the high-viscosity oil is returned to the tank. A high-viscosity oil heating device which supplies high-viscosity oil to a boiler burner when the temperature is higher than an appropriate heating temperature, wherein low-pressure steam is supplied to the heater together with high-pressure steam. Viscosity oil heating device. 2. A high-pressure steam is supplied to the heater when the boiler is operating, and the high-pressure steam is not supplied to the heater when the boiler is stopped, and the low-pressure steam is supplied to the heater. The high-viscosity oil heating device according to claim 1, wherein: 3. A temperature control means for adjusting a steam flow rate based on a temperature of fuel flowing through a fuel supply path from the heater in a steam supply path to the heater, wherein the temperature control means is controlled when the boiler is stopped. 3. The high-viscosity oil heating device according to claim 2, wherein the regulated temperature is set low and the regulated temperature of the temperature control means is set high during operation of the boiler. 4. An on-off valve is interposed in the high-pressure steam introduction path, and the opening and closing operation of the on-off valve is synchronized with the setting of the adjustment temperature of the temperature control means when the boiler is started and stopped. The high-viscosity oil heating device according to claim 3.