JPS5935956B2 - Method for producing emulsified fuel composition with low nitrogen oxide generation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a manufacturing method for obtaining a water-in-oil emulsified fuel composition that is used as a fuel with low nitrogen oxide (NOx) generation in boilers and other combustion equipment. .

In order to reduce the NOx concentration in combustion exhaust gas, that is, the amount of NOx generated, water has been conventionally added to hydrocarbon fuel.

However, since a more homogeneous fuel composition is required, an anionic, nonionic, or cationic surfactant (emulsifier) is generally added to emulsify the fuel composition.

The emulsified fuel composition thus obtained can be broadly classified into oil-in-water type (O/W type) and water-in-oil type (W2O type).

The former has a high viscosity and is usually used in gel form, and is also called gel kerosene (Japanese Patent Application Laid-Open No. 49-6
6705, 49-99102, 48-52803,
49-67908, 49-27502, 49-1
24102).

However, the viscosity of this material tends to change significantly depending on the strength of the emulsification dispersion and the progress of emulsification, and even when used in combustion equipment, it is difficult to adjust the air-fuel ratio, and the problem of corrosion remains in the wetted parts.

Moreover, most of the emulsification mixers used for emulsification are of the high-speed shearing type, such as homogenizers, which have problems in maintaining the sealing part and are generally expensive.

The latter water-in-oil emulsified fuel composition has a low viscosity, unlike the former.

Since oil is continuous and water is a dispersed phase, its physical properties are almost similar to kerosene, and its viscosity remains constant, so corrosion problems like the former do not occur.

Therefore, it can be applied to existing combustion equipment as is, and there is no need to make any particular improvements to the equipment itself.

However, a problem pointed out is that emulsion stability is poor.

For example, when intense shearing is applied, the phase changes to an oil-in-water droplet type, and the viscosity increases rapidly.

Also, emulsions are easily destroyed when exposed to temperature changes.

Under these circumstances, the inventors have determined that the boiling point is 150 to 2.
Using hydrocarbon oil (kerosene) at around 50°C as a fuel raw material,
We have endeavored to develop an emulsified fuel composition that has low viscosity and good emulsion stability at or near room temperature, and of course generates little NOx, so that it can be easily applied to existing combustion equipment.

At this time, surfactants having N atoms in their molecules were not used in order to avoid secondary pollution, and repeated examinations were conducted mainly from the viewpoint of the emulsification state of the nonionic emulsifier and the emulsification method.

As a result, we found that polyoxyethylene nonylphenyl ether is suitable as a nonionic emulsifier, that there is a certain limit on the number of moles of ethylene oxide added, and that static mixer is suitable as an emulsification mixer. It was mainly through these three points of knowledge that we were able to complete the invention.

That is, the method for producing an emulsified fuel composition of the present invention comprises:
Polyoxyethylene nonylphenyl ether with a weight coefficient of 0 to 30 and an average number of added moles of ethylene oxide 0.0
The present invention is characterized in that a mixture consisting of 5 to 5 parts by weight and the remainder kerosene is emulsified and dispersed using a static mixer to obtain a water-in-oil type emulsified fuel composition.

This will be explained in detail below.

First, kerosene was selected as the fuel raw material for the following reasons.

The main cause of NOx generation is N2 and 02 at high temperatures inside the fuel tank.
However, it is known that adding water to fuel oil reduces the amount of NOx (thermal NOx) generated.

However, when fuel oil containing N atoms such as heavy oil is used,
Since NOx (fuel NOx) is generated by the combustion, the NOx reduction effect is relatively reduced.

Therefore, in this invention, kerosene containing no N atoms is selected.

The blending amount is based on the total amount of the emulsified fuel composition of this invention.
89.95 to 65 weight ratio.

This is the result of taking into consideration the amount of water and emulsifier added, which will be described later, in order to fully demonstrate its performance as a fuel.

The next water to be added is whether it is industrial water or tap water.

The amount added is based on the total amount of the emulsified fuel composition of this invention.
The weight is limited to 10 to 30 weight, preferably about 20 weight.

This is because when the weight ratio is less than 10, the effect of reducing the amount of NOx generated decreases, and when the weight ratio exceeds 30, the effect of reducing the amount of NOx generated increases, but the combustion efficiency decreases and the emulsion This is because it has a negative effect on the stability itself and is likely to cause problems in handling and operation.

An important point in this invention is to use a polyoxyethylene nonylphenyl ether selected as an emulsifier, which has an average added mole number of ethylene oxide <Eod> of 4.

An EOp of 4 refers to one in which the number of ethylene oxide additions is mainly distributed between 2 and 6, and has a Poisson distribution.

If an emulsified fuel composition having an EOy of 3 or less or an EOp of 5 or more is used, an emulsified fuel composition with low viscosity and excellent emulsion stability cannot be obtained, and the object of the invention cannot be achieved.

For example, even if polyoxyethylene nonylphenyl ether of EOp3 is used and other emulsification is carried out according to the conditions of the invention, the resulting emulsified fuel composition will undergo phase separation into an oil phase and an aqueous phase in the temperature range of 20 to 60°C. will occur.

Further, even if polyoxyethylene nonylphenyl ether of BOpr5 is used and other emulsification is carried out according to the conditions of the invention, the resulting emulsified fuel composition tends to be of the oil-in-water type rather than the water-in-oil type.

This product has a remarkable increase in viscosity, and the emulsion system is very sensitive to temperature changes, resulting in poor emulsion stability.

Therefore, in this invention, polyoxyethylene nonylphenyl ether of EOp4 must be selectively used.

The amount used is 0.05 to 5 parts by weight, preferably 1 to 2 parts by weight, based on the total amount of the emulsified fuel composition of the present invention.

This is because when the weight ratio is less than 0.05, emulsion stability deteriorates, and when it exceeds 5 weight ratio, the emulsion stability is good but becomes uneconomical in terms of cost.

Another important point in this invention is that the three components described above are not only mixed and emulsified, but also that a static mixer is used as the emulsification method.

As the emulsification method generally used in this field, a physical dispersion method using ultrasonic waves or a stirrer is employed.

However, even if this method is applied to the emulsion mixing of the three ingredients, it is not possible to obtain a stable emulsion composition, and on the contrary, phase inversion to oil-in-water type occurs under high shear force. This will cause an increase in viscosity.

By the way, a static mixer is a device in which an element that causes flow division and radial mixing is enclosed in a pipe, and can be called an in-line mixer in a pipe.

According to this mixer, a mixing effect similar to an extrusion flow can be obtained, the progress of mixing can be accurately grasped, and therefore, programming is possible.

It is possible to mix, stir, and disperse all kinds of fluids with mathematical precision and economy while completely blocking contamination from outside air, and maintenance is also easy.

In this invention, as long as a good dispersion effect can be obtained, there is no need to impose any restrictions on the usage conditions, but to give an example of preferred usage conditions, feed pressure = 1 to 3 KLj/cr? t Number of elements: 4 to 12 Temperature: Room temperature is appropriate.

As is clear from the above, in this invention, kerosene, water, and polyoxyethylene nonylphenyl ether of EO-p4 are mixed and emulsified using a Suftic mixer, so that the emulsion has excellent emulsion stability at or near room temperature. N
It is possible to obtain an emulsified fuel composition that generates a small amount of Ox.

Each compounding agent is available at low cost, and the emulsification process is also economical, so it is advantageous in terms of cost.

Since the above-mentioned emulsified fuel composition has physical properties similar to those of kerosene, it can be applied as is without any modification even in existing combustion equipment.

Therefore, the present invention can provide economically advantageous emulsified fuel compositions that generate less NOx and are easy to handle for various types of existing combustion equipment such as boilers.

Example 1 A mixture of 10% by weight of water, 0.5% to 5% by weight of polyoxyethylene nonylphenyl ether, and the remainder of kerosene was mixed in a Suftic mixer (Nippon Toki Co., Ltd. C3M-1-12 type,
2 in series, number of elements 8), feed pressure 2 K7/
cyyt, flow rate 800 A/I-(, milk was dispersed at room temperature.

200 rrIl was immediately sampled from the obtained emulsified fuel composition, left to stand for 15 minutes at a temperature range of 0 to 60°C, and the emulsified state was observed.

The results are shown in Table 1 along with the temperature and EO-7 of polyoxyethylene nonylphenyl ether.

Example 2 Same as Example 1 except that the amount of water was 20% by weight.
An emulsified fuel composition was prepared in the same manner as above, and its emulsified state was observed.

The results are shown in Table 2.

Example 3 An emulsified fuel composition was prepared in the same manner as in Example 1, except that the amount of water was 30% by weight and polyoxyethylene nonylphenyl ether was added in a range of 1.0 to 5% by weight. was prepared.

The observation results of the emulsified state are shown in Table 3.

Analysis of the results in Tables 1, 2, and 3 shows that when using EOTf4 polyoxyethylene nonylphenyl ether as an emulsifier, water-in-oil emulsified fuel with good dispersibility at or around room temperature It can be seen that the composition is obtained.

In addition, polyoxyethylene nonylphenyl ether with an EOv5 or higher can only produce an oil-in-water type emulsified fuel composition, and with an EOi3 or lower, even though it is a water-in-oil type, the phase separation into a water layer and an oil layer occurs. occurs, and the effect of the invention cannot be obtained.

Example 4 *Polyoxyethylene nonylphenyl ether with EOi = 4 Based on the blending ratio in Table 4, four types (A
-D) The emulsified fuel composition was prepared, and it was supplied from inside the Suftic mixer via an injection pump to a boiler (SC, 99-II, manufactured by Ishikawajima-Harima Heavy Industries, Ltd.), and a combustion test was conducted.

When the NOx concentration in the combustion exhaust gas is measured, the results shown in the figure are obtained, and it is found that the emulsified fuel composition of the present invention has a remarkable effect of suppressing NOx generation.

[Brief explanation of the drawing]

The drawing is a diagram showing the NOx generation suppressing effect of the emulsified fuel composition produced in one example of the present invention.

Claims (1)

[Claims] 1 Emulsifying and dispersing a mixture consisting of 10 to 30% by weight of water, 0.05 to 5% by weight of polyoxyethylene nonylphenyl ether with an average added mole number of 4 of ethylene oxide, and the balance of kerosene using a Suftic mixer, A method for producing an emulsified fuel composition that generates a small amount of nitrogen oxides, the method comprising obtaining a water-in-oil type emulsified fuel composition.