JPH0139013B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for stopping co-combustion of liquid fuels with different particle sizes, and in particular, a method for determining the ratio of both oils during an emergency stop when burning oil in pipes containing heavy oil and C heavy oil. This is a method of extracting while maintaining the value.

In the past, it was common to use relatively low-fluorescence point oils such as A heavy oil and C heavy oil, coal, etc. as fuel for boilers, etc., but in recent years, heavy oils such as normal pressure or vacuum distillation residue oil, pitch etc. Quality oil also began to be used. However, this heavy oil is an oil with extremely high particle size that contains a large amount of high-boiling point fractions, and normally has extremely low fluidity at room temperature to several tens of degrees Celsius, so it is generally heated to 150 degrees Celsius or higher and stored in tanks. There is. Furthermore, since the heavy oil contains a large amount of impurities, if it is burned alone, it may cause pollution problems such as air pollution, which is not desirable. Therefore, it is conceivable to mix heavy oil that has been preheated to 150° C. or higher in a storage tank with oil that has a lower boiling point and contains fewer impurities, such as heavy oil C, and then supplies the mixture to a burner. In general, when using C heavy oil and heavy oil together, the proportion of heavy oil is adjusted in the range of 1 to 100% by volume, taking into account the effect of exhaust gas on the environment and the combustion state of the boiler. (referred to as mixed oil).

When the boiler is to be stopped, pipes, burners, etc. containing heavy oil are replaced with C heavy oil, and then the boiler is stopped. However, in some cases, such as when a boiler is brought to an emergency stop, mixed oil or heavy oil may remain in the pipes. Under such conditions, problems such as clogging may occur when the boiler is restarted. Furthermore, when constructing a part of the piping, it is necessary to drain the oil inside the piping. As mentioned above, in the co-firing process, it may be necessary to return the oil in the piping to the storage tank. However, conventionally, there are the following problems in removing oil from a pipe after heavy oil and C heavy oil are mixed. The temperature inside the C heavy oil tank is generally 50 to 60°C, so when heavy oil that has been given fluidity at a high temperature enters the tank, it is rapidly cooled and solidified within the tank. Surprisingly, this solidified material is not easily dissolved in heavy oil C and exists in the form of lumps, which is undesirable as it causes clogging of pipes and pumps. Also, when the mixed oil of heavy oil and C heavy oil is returned to the heavy oil tank, the temperature inside the heavy oil tank is generally 150℃ or higher (usually 150 to 200℃), so the volatile components in the C heavy oil There is a risk of rapid heating and evaporation, ignition and explosion.

The present invention provides a novel method for solving the above problems. That is, in a combustion system where C heavy oil and heavy oil are mixed in a line and supplied to a burner, the present invention converts the mixed oil of heavy oil and C heavy oil remaining in the piping when combustion is stopped, etc. to C heavy oil. This is a method for stopping co-combustion of liquid fuels with different viscosities, characterized by adjusting the volume ratio of heavy oil to 1 part heavy oil to 10 parts or more of heavy oil C, and returning it to the heavy oil tank C.

According to the method of the present invention, the oil remaining in each pipe during an emergency combustion shutdown, etc., especially the oil in the pipe where heavy oil and C heavy oil are mixed, can be returned to the tank without causing the above-mentioned problems.

Hereinafter, the method of the present invention will be explained in detail based on the drawings, but the present invention is not particularly limited to the following drawings.

FIG. 1 is a combustion system diagram showing a typical example of the present invention.

In the figure, C heavy oil passes through C heavy oil tank 1, valve 2, strainer 3, and pump 4, and heavy oil passes through heavy oil tank 5, valve 6, strainer 7, and pump 8, and both are mixed at mixing section 9. and is mixed in a mixer 12 and supplied to a burner 10. The mixing method at this time is arbitrarily selected depending on the type and capacity of the burner. Further, C heavy oil may be mixed with heavy oil in advance through a partial bypass pipe 11 from the outlet of the pump 4.

In the present invention, the piping 17 leading from the mixing section 9 to the burner 10 and the piping 18 leading from the heavy oil tank 5 to the mixing section 9 are particularly problematic when combustion is stopped, and these are all piping containing heavy oil. It is.
Generally, during operation, the temperature inside the C heavy oil tank 1 is heated to 50 to 60℃, and the inside of the heavy oil tank is heated to 150 to 200℃, so there is no problem with the fluidity of the oil in each piping, but operation is When stopped, the temperature of the fluid in the pipe becomes the temperature of the outside air, so the fluid solidifies, especially in pipes containing heavy oil. Therefore, when the operation is stopped, it is necessary to replace the oil in each pipe with C heavy oil and then return it to the tank. The present invention solves the problem that occurs when a mixed oil containing heavy oil and C heavy oil is returned to a C heavy oil tank or a heavy oil tank as it is by setting the ratio of C heavy oil and heavy oil in the mixed oil to a specific value. , C heavy oil tank is characterized by returning it to the tank, and the method for that purpose is not particularly limited. For example, heavy oil and C in Figure 1
Lines where heavy oil is mixed, for example, pipes 17, 20,
a mixer 12' in at least a portion of 18;
The C heavy oil pump 4 is operated to pump the heavy oil in the mixer, and the bypass pipe 13 is operated so that the C heavy oil and heavy oil are in a specific ratio. Of course, in this case,
Flow control valve 15 of line 14 leading from heavy oil piping to mixer 12 and mixer 1 from burner 10
It is preferable to also control the flow rate regulating valve 16 of the line leading to line 2.

In the present invention, what is particularly important is the mixing ratio of C heavy oil and heavy oil when returning the mixed oil to the C heavy oil tank, and the volume ratio of C heavy oil and heavy oil to 1 heavy oil. C heavy oil should be 10 or more, preferably 20 or more. In the present invention, if the ratio of C heavy oil to 1 part of heavy oil is less than 10, it is not preferable because when the heavy oil is returned to the C heavy oil tank, the heavy oil will block in the tank and cause clogging of the tank. Further, although there is no particular upper limit on the ratio of C heavy oil and heavy oil, the total amount of C heavy oil and heavy oil is determined by the pumping capacity.

In the present invention, a known method is used to detect whether the ratio of C heavy oil to heavy oil is above a specific value, but generally a detection method based on the temperature of the oil at the outlet of the mixer 12' is used. It will be done.

The heavy oil C used in the present invention has a kinematic viscosity of 50 to 1000 cst at 50°C, and the heavy oil has a kinematic viscosity of 200 to 1000 cst at 120°C.

In addition, in the present invention, things other than the above, such as the shape of the burner, the combustion system, the tank, the valve,
Known shapes, structures, positions, etc. of the strainer and flow control valve may be used without any particular restriction.

[Brief explanation of drawings]

FIG. 1 is a combustion system diagram showing the present invention. In the figure, 1 is a C heavy oil tank, 2 is a valve, 3 is a strainer, 4 is a pump, 5 is a heavy oil tank, 6 is a valve, 7 is a strainer, 8 is a pump, 9 is a mixing section, 10 is a burner, and 11 is a Bypass pipe, 12
and 12' is a mixer, 13 and 14 are bypass pipes,
15 and 16 are flow control valves, 17 is a pipe from the mixing section to the burner, 18 is a pipe from the heavy oil tank to the mixing section, 19 is a C heavy oil line, and 20 is a pipe from the burner to the heavy oil tank. .

Claims (1)

[Claims] 1 In a combustion system that mixes C heavy oil and heavy oil and supplies it to the burner, the mixed oil containing heavy oil that remains in the piping when combustion is stopped is converted into heavy oil with a volume ratio of C heavy oil and heavy oil. A method for stopping co-combustion of liquid fuels with different viscosities, characterized by adjusting the ratio of C heavy oil to 10 to 10 or more, and returning the mixture to a C heavy oil tank.