JPH02287005A - Combustion method of fuel oil - Google Patents

Abstract

PURPOSE:To stabilize the flame for reducing the generation amount of nitrogen oxides and improving the combustion efficiency by a method wherein fuel oil is added with water and alcohol, agitated, emulsified and burned. CONSTITUTION:Fuel oil like heavy oil, etc. is added with about 5 - 40 vol. % of water and about 4 - 10 vol.% of alcohol such as methyl alcohol, ethyl alcohol, etc., and agitated and emulsified by means of an emulsified oil produc tion unit with a mixer. Thereby, water and alcohol are turned into very fine liquid particles having a diameter of around 3 - 15mum, and supplied to a combus tion burner at a pressure ranging 1.5 - 5.5 kg/cm<2> corresponding to the feed rate to burn them. By this constitution, a reduction in nitrogen oxide generation amount and an improvement in the combustion efficiency can be achieved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for burning fuel oil in boiler equipment and the like.

(Prior Art) Fuel oil such as heavy oil is used in boiler equipment and the like. As a combustion method for this type of fuel oil, a so-called emulsion combustion method is used in which water is added to fuel oil, stirred to emulsify, and then combusted.

In the emulsion combustion method mentioned above, the water droplets dispersed in the oil cause the micro-explosion of the oil droplets and the water gas reaction, which facilitates complete combustion of the fuel oil compared to fuel oil without adding water, and eliminates harmful substances in the exhaust gas. This has the advantage of reducing the amount of nitrogen oxides and soot.

According to this method, water added to fuel oil is atomized into fine water droplets by an emulsion oil production device equipped with a mixer. Then, the fuel oil forming the continuous phase is atomized into oil droplets by the combustion steam injected to the tip of the combustion burner. In this case, as a condition for reducing nitrogen oxides in the exhaust gas, it is necessary to reduce the pressure of the combustion steam more than when using fuel oil to which no water is added.

(Problem to be Solved by the Invention) However, in this fuel oil emulsion combustion method, if the pressure of the combustion steam is lowered than when using fuel oil without adding water, the tip of the combustion burner There is a problem in that unburned carbon adheres to the parts and normal combustion flame formation cannot be maintained for a long period of time.

As a result, the pressure of the combustion steam cannot be reduced significantly, making it difficult to maintain nitrogen oxides in the exhaust gas below the original design value of 210 ppm (Oz 4% equivalent). There is a problem (the pollution regulation value is 230 ppm or less, and the desired value is 210 ppm or less).

The present invention solves the above-mentioned problems, and its purpose is to form a normal combustion flame and reduce nitrogen oxides in the exhaust gas to, for example, the original design value of 210p.
It is an object of the present invention to provide a fuel oil combustion method capable of maintaining and reducing pm (Ox 4% equivalent value) or less and increasing the combustion efficiency of fuel oil.

(Means for Solving the Problems) The fuel oil combustion method of the present invention is characterized by adding water and alcohol to fuel oil, stirring the mixture to emulsify it, and burning it, thereby achieving the above object. be done.

In the present invention, the fuel oil is usually heavy oil (A, B,
Generally, about 5 to 40% by volume of water and about 4 to 10% by volume of alcohols are added to the heavy oil and stirred in an emulsion oil production equipment equipped with a mixer to remove the water and water in the fuel oil. Alcohols are atomized into fine droplets.

The water used may be either tap water or well water. As alcohols, methyl alcohol, ethyl alcohol, isopropyl alcohol, butyl alcohol, etc. are used, but when a large amount of the above alcohols are used as a solvent in a factory, the recovery that occurs in this solvent recovery process is Preferably, alcohols are used.

The fuel oil is heated to a temperature below the boiling point of the alcohol used, and appropriate amounts of water and alcohol are added thereto.

When the amount of alcohol added increases and the heating temperature of the fuel oil becomes high, the pipes are filled with alcohol vapor and the pressure of the fuel pulsates, making it difficult to achieve good combustion.

To add water and alcohol to fuel oil and emulsify it by stirring, use a commercially available emulsion oil production device that adds only water to fuel oil and emulsifies it by stirring, but it is also possible to add both water and alcohol. It can be used by modifying the water transport piping and mixing tank. This emulsion oil production device is then attached to the oil supply piping of conventional boiler equipment.

When fuel oil, water, and alcohol are mixed and stirred and emulsified in the emulsion oil production apparatus as described above, the water and alcohol are dispersed in the fuel oil as fine droplets of about 3 to 15 microns. This emulsion is fed under pressure to a combustion burner of boiler equipment at a pressure of about 1.5 to 5.5 kg/aj depending on the amount supplied.

The pumped emulsion preferably has a kinematic viscosity of 20 to 3, right before the tip of the combustion burner.
It is heated to 0 centistokes. In this emulsion, the fuel oil forming the continuous phase is heated to 100μ by the combustion steam injected to the tip of the combustion burner.
The oil is atomized into small oil droplets, and combustion takes place in this state.

The pressure of the combustion steam is generally about 0.4 kg/cnT higher than the pressure of the emulsion to be pumped.

(Function) When water is added to fuel oil, stirred to emulsify, and then combusted, if alcohol is added along with the water, nitrogen oxides and other substances in exhaust gas can be removed without reducing the pressure of combustion steam. Soot weight is reduced. Therefore, unburned carbon does not adhere to the tip of the combustion burner.

Furthermore, the amount of water added can be reduced by the amount of alcohol added, and the loss of heat can be prevented by the amount equivalent to the amount of heat of evaporation of bones that have lost water.

(Example) Examples and comparative examples of the present invention are shown below.

Water transport piping and The mixing tank was modified and the modified device was installed in the oil supply piping of a 20 ton/hr heavy oil boiler facility.

In the emulsion oil production equipment described in above, 30 parts by volume of A@oil,
60 parts by volume of C heavy oil, 5 to 6 parts by volume of water, 4 to 5 parts by volume of recovered isobucobyl alcohol at a rate of 6H900e/hr, mixed, stirred and emulsified, and heated to 65°C.
h and jets it out from the tip of the combustion bar 3-1 of the heavy oil boiler equipment at a pressure of about 4.2 kg/c4, and at the same time, the combustion steam is sent to the tip of the combustion burner at a pressure of 0.0 kg/c4, which is lower than the pressure of the fuel oil. It was injected and burned at a pressure higher than 4 kg/cml.

In this case, unburned carbon does not adhere to the tip of the combustion burner, and the nitrogen oxides in the exhaust gas from the heavy oil boiler equipment are 200 ppm (0□4% conversion value), which is 210 ppm ( 0□4% exchange rate) was satisfied.

Comparison - Example 1 In Example 1, no recovered isopropyl alcohol was added, the 5 to 6 parts by weight of water was changed to 10 parts by weight, and the combustion steam was added to 4.2 kg, which was approximately the same pressure as the fuel oil.
The combustion was carried out in the same manner as in Example 1 except that the fuel was ejected at a pressure of /cJ.

In this case, unburned carbon adheres to the tip of the combustion burner, and normal combustion flame formation cannot be maintained for two months.
Nitrogen oxides in exhaust gas from heavy oil boiler equipment decreased from the initial 210 ppm (Oz 4% conversion value) to 230 ppm.
(Oz 4% conversion value), which is the pollution regulation value of 2.
Although 30ppm (equivalent to 4%) was met, it did not meet the required value of 210ppn+ (0□4%), which is the value required by pollution regulations.

In Example 1, combustion was carried out in the same manner as in Example 1, except that neither water nor recovered isopropyl alcohol was added at all.

In this case, no unburned carbon adhered to the tip of the combustion burner, but nitrogen oxides in the exhaust gas from the heavy oil boiler equipment were 240 ppm (0□4% conversion value), which is the pollution regulation value. 230 ppm (OX 4% equivalent value) was not satisfied.

(Effects of the Invention) As mentioned above, the fuel oil combustion method of the present invention adds water and alcohol to fuel oil, stirs and emulsifies the mixture, and then burns the mixture, so it can last for a long time compared to the conventional method in which alcohol is not added. As a result, a normal combustion flame is formed and nitrogen oxides in exhaust gas can be reduced. Moreover, the combustion efficiency of fuel oil can be increased.

Therefore, the method of the present invention is useful for pollution prevention and energy conservation in boiler equipment that obtains thermal energy by burning heavy oil.

Claims (1)

[Claims] 1. A fuel oil combustion method characterized by adding water and alcohol to fuel oil, stirring the mixture to emulsify it, and burning it.