JPH0225090B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention particularly relates to a method of blending a fuel that has a high viscosity and is therefore preheated to increase fluidity and then supplied to a burner for combustion.

Because of its high viscosity, heavy oil C is known as a fuel that is heated beforehand and then supplied to a burner such as a boiler.

However, in the recent petroleum situation, it is being considered to supply even higher viscosity oil, ie, vacuum distillation residue oil such as crude oil, so-called pitch or asphalt type, to a burner as fuel oil and burn it.

In this specification, oils having even poorer fluidity than heavy oil C as described above are collectively referred to as inferior residual oils. In general, inferior residual oil has extremely poor fluidity or is solid at room temperature, and is extremely unsuitable for fluid combustion systems where fuel is supplied through piping at or near room temperature. By heating it, its viscosity is lowered and it can be handled as a fluid. However, when combustion is stopped, if these inferior residual oils remain in the fuel supply piping, the temperature decreases due to heat radiation, making it difficult to fluidize or solidify, making it difficult to work with. In order to prevent this, it is sufficient to provide a heating device to the piping and operate the heating device all the time, but this results in a loss of energy.

For this reason, it is advantageous to supply C heavy oil or an oil having a lower viscosity to the piping when the combustion is stopped or when the piping is started up before it is warmed up yet.

In addition, inferior residual oil generally contains large amounts of impurities other than hydrocarbons, such as sulfur, nitrogen, residual carbon, and heavy metals such as vanadium, and if it is burned as is, it will have a negative impact on the boiler and the environment. This is a concern. Therefore, it is necessary to take some measures to burn it out.

For the above-mentioned reasons, it is proposed that when burning inferior residual oil, it should be mixed and burned with oil of lower viscosity, such as heavy oil C, on a short-term or regular basis. In this case, in so-called on-off switching, the properties and handling of the fuel oil differ widely, so it is predicted that there will be an adverse effect on the boiler, the environment, etc.

Therefore, it is necessary to gradually change the mixing ratio over time to reach a desired mixing ratio or one of them.

Furthermore, in order to maintain a constant mixing ratio, it is necessary to monitor the mixing state and constantly make fine adjustments to the mixing ratio. In this case, in particular deviations from predetermined values must be corrected with a fast response.

The present invention has been proposed to solve the above-mentioned problems, and its gist is to mix and burn inferior residual oil and C heavy oil heated to different temperatures by mixing the two oils in a pipe. The method is to supply oil to the burner, and measure the flow rate and temperature of only one oil after mixing. Using the pre-measured specific heat of each oil, estimate the flow rate of the other oil using the formula below, and then This fuel blending method is characterized by adjusting the mixing ratio of both oils and/or the amount of oil supplied to the burner by operating control valves provided in the supply pipes of each oil.

V ₂ = | C ₁ V ₁ (T ₁₂ − T ₁ )/C ₂ (T ₁₂ − T ₂ ) | (However, in the formula, V ₁ , C ₁ and T ₁ are the flow rate of one oil,
Specific heat and temperature before mixing, V ₂ , C ₂ and T ₂ are the flow rate of the other oil, specific heat and temperature before mixing, and T ₁₂
is the temperature after mixing both oils. ) In the present invention, fuel oil is first heated to a viscosity suitable for combustion. This temperature is generally set so that the viscosity is a predetermined value within the range of 20 to 50 centistokes (hereinafter abbreviated as cst). Usually, it is around 80-110℃ for C heavy oil, and 180-220℃ for inferior residual oil.
In many cases, the temperature ranges are different, and when setting a practical viscosity, the temperature ranges do not overlap.

In the present invention, C heavy oil and inferior residual oil are mixed by connecting pipes. Therefore, compared to the case where a so-called mixing tank is used, the mixing ratio of the oil supplied to the burner can be changed very quickly without liquid pool slippage.

In the present invention, oils that have been heated to the same viscosity are generally easily mixed by supplying them from separate pipes, but in order to ensure more uniform mixing, the oils are added to the pipes after mixing. It is also a preferred embodiment to install mixing equipment such as a line mixer.

The most important feature of the present invention is that the mixing ratio of both oils can be adjusted by using easily measurable temperature as the main indicator and knowing the flow rate of only one oil. That is, in general, it is easy to control oil to keep its temperature constant, and it is also easy to measure the specific heat of each oil. Therefore, by measuring the temperature, the higher the viscosity, the more difficult it is to measure the fluid and the greater the energy loss (higher flow resistance). It controls the

Hereinafter, an example of the present invention will be explained with reference to the drawings.
FIG. 1 is a diagram of a piping system for compounding according to the present invention. That is, for example, when C heavy oil A and poor quality residual oil B are mixed and burned in burner K, A and B are fed by pumps and 4, respectively, and are connected to heaters 1 and 2 in the piping routes, respectively. is heated to a predetermined temperature.

On the way, A is checking the flow rate with the flowmeter FI.

The pressure of both oils is measured by pressure gauge PI and the operating status of pumps 3 and 4 is controlled. In addition, the temperature of each oil was measured using a thermometer TI, and the temperature of each oil was measured.
and 2. The heating method of the heater is not particularly limited, but in this figure, steam is used and a steam valve adjustment method is shown.

The respective oils further pass through control valves 5 and 6 and check valves 7 and 8, join at point P, and are further mixed uniformly in a mixer M provided as necessary, after which the temperature is measured by a thermometer 9. is measured and burned in burner K. Of the above lines, each value of flowmeter FI and thermometer 9 (and signal from TI as necessary)
are collected in the calculation mechanism M, and the opening degree of each control valve 5 and 6 is adjusted based on these values. P
In order to smoothly merge at a point, it is also preferable to set the pressure of the oil that is mixed in a small amount to be slightly higher.

For example, if one oil A has a specific heat C ₁ and is set at a temperature T ₁ , and the other oil B has a specific heat C ₂ and is set at a temperature T ₂ , the temperature after mixing will be T ₁₂ and the flow rate of A. is _{V 1} , the unknown flow rate V ₂ of B can be approximately determined as V ₂ = |C ₁ V ₁ (T ₁₂ − T ₁ )/C ₂ (T ₁₂ − T ₂ )| /V ₂ can be easily achieved by operating the regulating valves 5 and 6.

Similarly, the total flow rate can be controlled by adjusting the opening degree of valve 10 and valves 5 and 6.

Note that these operations can of course be performed by automatic control, or may be performed manually. Further, the type, type, installation position, and arrangement order of each device can be freely changed within the scope of those skilled in the art in accordance with the spirit of the present invention.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of piping for carrying out the compounding of the present invention. In the figure, A and B are different types of fuel oil, P is a pump, FI is a flow meter, PI is a pressure gauge,
TI stands for thermometer, M stands for mixer, and K stands for burner. Further, 1 and 2 are heating means, 5 and 6 are control valves, 7 and 8 are check valves, and 10 is a control valve, respectively.

Claims (1)

[Claims] 1. When mixing and burning inferior residual oil and C heavy oil heated to different temperatures, both oils are mixed in a pipe and supplied to a burner, and the flow rate of only one of the oils is controlled. and the temperature after mixing, and using the pre-measured specific heat of each oil, estimate the flow rate of the other oil using the formula below, and operate the control valves installed in the supply piping for each oil. A fuel blending method characterized by adjusting the mixing ratio of both oils and the amount of oil supplied to the burner. V ₂ = | C ₁ V ₁ (T ₁₂ − T ₁ )/C ₂ (T ₁₂ − T ₂ ) | (However, in the formula, V ₁ , C ₁ and T ₁ are the flow rate of one oil,
Specific heat and temperature before mixing, V ₂ , C ₂ and T ₂ are the flow rate of the other oil, specific heat and temperature before mixing, and T ₁₂
is the temperature after mixing both oils. )