JPH05125371A - Fuel composition - Google Patents

Abstract

PURPOSE: To provide a fuel compsn. consisting of an oil-in-water type emulsion containing sulfur-containing petroleum with specific API specific gravity and an emulsifying surfactant aq. soln., including a solid sulfur absorbent in a solid particle form and reduced in the generation of sulfur oxide at a time of combustion.

CONSTITUTION: An oil-in-water type emulsion is formed from 50-90 vol % of sulfur-containing petroleum having API specific gravity of 5-25° and a solid sulfur absorbent is added to the emulsion in a form of a solid particle form of alkaline earth metal oxide, hydroxide, carbonate or bicarbonate having an average particle size of 2-50 μm in an amt. so that a molar ratio of alkaline earth metal and sulfur in petroleum is (0.2:1)-(5:1) to obtain a novel fuel compsn. containing a special sulfur absorbent having oil droplets with an average liquid droplet size of 2-50 μm and reducing the generation of sulfur oxide at a time of combustion.

COPYRIGHT: (C)1993,JPO

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel fuel composition comprising a viscous sulfur-containing petroleum-in-water emulsion and a particulate sulfur absorbent which reduces the production of sulfur oxides when the fuel burns. Is.

[0002]

BACKGROUND OF THE INVENTION Low API gravity and viscous crude oils are found in, for example, Canada, the Soviet Union, the United States, China and Venezuela. This type of feedstock is characterized as bitumen according to the UNITAR definition of crude oil specified in the minutes of the First International Conference on Heavy Oil and Tar Sands, 1979. These crudes are currently produced either by mechanical pumping, steam injection or mining.
Until recently, these crude oils have not been widely used as fuels for many reasons. Reasons for this include the difficulty of producing, transporting and handling this raw material, as well as the generation of large amounts of sulfur oxides and unfavorable combustion characteristics including non-combustible solids.

Other refractory hydrocarbon materials are residual oils from refining processes such as distillation (atmospheric and vacuum), cracking, visbreaking and other operations.
These raw materials are generally similar in viscosity to bituminous raw materials, but have a wide range of viscosities, some of which are more viscous and some of which are less viscous than bituminous raw materials. The same difficulties described above for bitumen affect its use.

As far as the transport and handling of bitumen and residual oils, these problems have recently been addressed by EP 01564.
It was overcome by the technique described in 86B1. This patent consists of directly mixing 70-98% by volume of viscous petroleum with 30-2% by volume of an emulsifying surfactant or an aqueous solution of an alkali, the percentages being expressed as% by volume of the total mixture in water of petroleum. In the method for producing a HIPR emulsion, petroleum is mixed at 200-25 at a mixing temperature.
2-50 having a viscosity in the range of 10,000 mPa · s and the mixture separated by an interfacial lamina in the range of 10-1,000 reciprocal seconds at low shear conditions.
A method of making and claiming a HIPR emulsion in petroleum, characterized in that it is carried out in such a way that an emulsion consisting of highly distorted oil droplets having an average droplet size in the range of μm, is produced. There is.

The HIPR emulsion so formed can then be diluted with the aqueous phase to the desired viscosity or concentration.

[0006]

However, the problem of the generation of sulfur oxides remains, and when it is necessary to reduce the generation of sulfur oxides, this problem has recently become apparent during or after combustion. The method of processing is discussed.

One method of reducing the production of sulfur oxides involves injecting limestone into the combustion furnace. Limestone reacts with sulfur oxides to produce solid calcium sulfate particles,
The solid particles are removed from the flue gas by conventional particle control equipment.

Another method involves the desulfurization of flue gas by mixing calcium oxide and water with the flue gas from the combustion furnace.

These two methods are expensive and require the use of special equipment for injecting the sulfur absorbent into the combustion furnace or flue gas pipe.

The inventor has invented a novel fuel composition in which the solid sulfur absorbent is incorporated in the fuel itself and is not press-fitted separately.

[0011]

According to the present invention, 5-2
50- of sulfur-containing petroleum having an API specific gravity in the range of 5 °
It consists of an oil-in-water emulsion containing 90% by volume, preferably 60-75% by volume, and 50-10% by volume, preferably 40-25% by volume, of an aqueous solution of an emulsifying surfactant, the volume% being both Shown as a percentage of the total volume of the liquid phase, and the oil droplets are 2-50 microns, preferably 5-30.
In fuel oil compositions having an average droplet size in the micron range, the emulsion further comprises a solid sulfur absorbent in the form of solid particles of an alkaline earth metal oxide, hydroxide, carbonate or bicarbonate. The solid particles have an average diameter in the range of 2-50 microns, preferably 5-30 microns, and the molar ratio of alkaline earth metal in the solid to sulfur in petroleum is 0.2: 1-5. : 1 preferably 0.5: 1-3:
There is provided a fuel oil composition characterized in that it is present in an amount such that it is in the range of 1.

As far as the size of the solid particles is concerned, there is a need to strike a balance between conflicting requirements. Very small particles appear to be most efficient, as sulfur scavenging is related to surface area, with smaller particles having a larger surface area per mass compared to larger particles. However, although the inventors have found that very small particles, such as particles of the size of 5 microns, adsorb sulfur more readily, they also release sulfur more rapidly at high temperatures and are stable above 1100 ° C. I found out to lose. Furthermore, very small particles tend to deposit on the heat transfer surface and are more expensive to manufacture.

The slightly larger particles have less initial sulfur uptake, but are still effective sulfur absorbers, are more stable, are less prone to deposit formation on heat transfer surfaces, and are less expensive.

Taking into account the above constraints, the particle size of the solid sulfur absorbent should be similar to the size of the oil droplets.

Suitable sulfur absorbers include calcium hydroxide,
Includes magnesium carbonate and magnesium oxide.

The preferred sulfur absorbent is calcium carbonate.

Suitable calcium carbonate particles having a particle size in the range of 2-50 microns can be obtained as a by-product from the kaolin industry or can be obtained by milling.

The degree of monodispersity of the emulsion is preferably such that at least 60% of the volume of the oil droplets has an oil droplet size within ± 70% of the average oil droplet size, most preferably ± 30%. It is something.

The emulsion is preferably EP 01
It is manufactured by the method described in Japanese Patent No. 56486B1.

The viscosity of petroleum at the emulsification temperature is 200 mPa.
If more than s, it has generally been found more convenient to produce an emulsion suitable for combustion using a two-step process, emulsification followed by dilution. When the viscosity of petroleum is 200 mPa · s or less, the one-step method, that is, the method of diluting only by emulsification is usually sufficient.

In the two-stage process, the petroleum concentration in the first-stage emulsion is preferably in the range 80-95% by volume and can be diluted with the second-stage emulsion to 60-75% by volume.

Suitable oils for the emulsification process include atmospheric and vacuum distillation residue oils as well as cracking, visbreaking and other residue oils.

Other oils that can be emulsified include Canada, the United States,
It includes the viscous crude oils found in Venezuela and the Soviet Union, such as Lake Margarito crude oil from Alberta, Hevito crude oil from Oklahoma, and Ceronegro crude oil from Orinoco Oilbelt.

The emulsifying surfactant may be nonionic, ethoxylated ionic, anionic or cationic, but is preferably nonionic.

Suitable nonionic surfactants are those whose molecules contain hydrophobic hydrocarbyl groups and hydrophilic polyoxyalkylene groups. The latter is preferably
It contains 9-100 ethylene oxide units. A preferred nonionic surfactant is an ethoxylated alkylphenol containing 15-45 ethylene oxide units per molecule, which is inexpensive and commercially available.

Ethoxylated nonylphenols containing about 20 ethylene oxide units are very suitable. A single surfactant is suitable, no blend of two or more surfactants is required.

Surfactants are suitably used in amounts of 0.5-5% by weight, expressed as% by weight of the aqueous solution.

Droplet size can be adjusted by varying any or all of the three major parameters: mixing intensity, mixing time and surfactant concentration. Increasing any or all of these parameters decreases droplet size.

The emulsification process is carried out over a wide range of temperatures, for example 20-2.
It can be carried out up to 00 ° C and is important as long as its temperature influences the viscosity of the petroleum. The emulsification process is generally performed under overpressure due to operational constraints.

High-viscosity fuel oil-in-water emulsions often have viscosities as low as 3-4 orders of magnitude lower than petroleum itself, which results in significantly easier pumping and considerably less energy. Moreover, since the oil droplets are already in the atomized state, the emulsified fuel petroleum is suitable for use in low pressure burners, requiring little preheating and thus further saving capital costs and energy.

The fuel oil emulsion according to the present invention has a uniform and high quality and burns efficiently to remove particulate matter and NO.
The occurrence of both SOx and SOx is low and SOx is even lower.
This is a rare and extremely beneficial combustion characteristic. Usually, when the generation of particulate matter is low, the generation of high NOx is accompanied,
The reverse is also true. With appropriate burners and optimal excess air, particulate matter emissions can be reduced to fuel ash content levels while keeping NOx emissions low.

This is believed to be the result of the emulsion's small droplet size and high monodispersity and the presence of water.

This reduction of SOx is comparable to the reduction of SOx in the current direct injection method of absorbent, and in the method of the present invention, since the absorbent is directly incorporated in the fuel, There is also an advantage that a direct press fitting device is not required.

The solid waste produced can then be easily collected by conventional equipment. Therefore, if the production of sulfur dioxide must be reduced, there is no need to further desulfurize the flue gas to burn the fuel. This is attractive for small-scale users where significant changes in manufacturing equipment are uneconomical and not appreciated.

"Brush" flue gas to comply with legal regulations
If it is necessary to reduce SOx a little more,
Sulfur absorbers in emulsion fuels are useful.

Apart from the quality of the emulsion itself, the most important parameters affecting the combustion of the emulsion are the type of burner used, the amount of excess air used and possibly the characteristics of the combustion chamber.

Suitable burners include those in which steam, air or fuel gas is used as the atomizing fluid using an atomizer.

A suitable excess air amount is 1-50%, preferably 2
It is in the range of -20%.

In order to maintain optimum combustion properties, the emulsion needs to remain water continuous until it is atomized. In practice this means
It means that the emulsion should not be overheated, should not be exposed to high temperatures for a long time, and should not be oversheared.

[0040]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments and the accompanying drawings. The figure shows SO ₂ absorption by calcium carbonate, a sulfur absorbent in emulsion fuels.

Example 1 Combustion of emulsion fuel was carried out in a drop tube furnace (DT
P). This furnace is an electrically heated laminar reactor in which the combustion state of the fuel spray can be followed over a wide range of conditions over time.

The fuel used was an oil / water emulsion with an initial oil / water ratio of 85:15, then 70:
Diluted to 30. Emulsion is EP 0156
It was prepared by the method described in Japanese Patent No. 486B1. Base oil is LIF
O [Labela Inland Fuel Oil
nd Fuel Oil)], a petroleum refinery residual fuel oil. The LIFO analysis values are shown in Table 1. The stabilizing surfactant was a nonionic nonylphenol ethoxylate containing about 20 ethoxy groups per molecule and was present in the final emulsion at 0.44% w / w. The emulsion had an average droplet size of 8 μm and was stable even during atomization. The base oil used as a comparative example for the absorbent test was prepared by the same method at 70:30.
Of LIFO emulsion. The test fuel is 85:
Prepared by adding calcium carbonate to the dilution water used to make the 70:30 test emulsion from the 15 emulsion.

The first test emulsion contained 14.4% by weight of 5 μm calcium carbonate. Since the sulfur content of the fuel oil was 3.01% by weight, the fired emulsion had a Ca: S molar ratio of 2.75: 1. The second test emulsion is 1 of calcium carbonate with a particle size of 25 μm.
It contained 0.1% by weight. This emulsion has 1.8:
It had a low Ca: S molar ratio of 1. The emulsion flow rate was maintained at a level that gave a petroleum equivalent of 3.5 g / min. The furnace temperature was adjusted to 900 ° C. while the total combustion air was kept constant at 1.72 bar gauge pressure at 15 liters / min and 11 liters / min, respectively. Further experiments were carried out at 1100 ° C. in order to investigate the effect of temperature on the performance of the coarse calcium carbonate particles.

When the oxygen content in the exhaust gas is 2%, S
Gas analysis measurements were performed for O ₂ , CO, NOx and CO ₂ . The generated gas is measured for a residence time of 150-1500
I went during ms. The solids were collected using a cyclone with a residence time of 1500 ms and analyzed by SEM, Malvern particle size analysis and XRF methods. The results are shown in Table 2.

The solids were left in a thermobalance at 1200 ° C. for 30 minutes to see if the absorbent had fully sintered while passing through the DTF. The results are shown in Table 3.

The results of measuring the SO ₂ level in the exhaust gas at various residence times in DTF are shown in FIG. SO ₂ levels in the exhaust gas varied between 270 and 1950 ppm depending on the physical form of the absorbent and the experimental conditions. The expected SO ₂ evolution value was 1980 ppm, assuming complete combustion and oxidation of the fuel sulfur. The base emulsion's SO ₂ evolution corresponded to this expected level, indicating that combustion and SO ₂ evolution were essentially complete within 200 ms.

SO ₂ level measurements for ₅ μm CaCO ₃ particles show residence times from 160 ms to 1350 m.
s from 270 ppm to 620 ppm
Increase to. Therefore, SO ₂ seems to be adsorbed initially, but then released from the absorbent during the rest of the passage through the furnace. A complete sulfur balance could not be taken.
However, the sample of collected ash shown in Table 2 contains 21 mol% calcium as sulfate. Bonded sulfur and generated S
From the result of measuring the O ₂ gas, a good balance balance of sulfur was obtained, and it is considered that the produced SO ₃ is relatively small from the balance balance. At the outlet of the DTF, the total sulfur retention is 66%, which is a good result as compared with the direct injection method of the absorbent. Thus, the availability of calcium is good, which is a reflection of the extremely small size of the absorbent particles. If all the sulfur initially captured at 160 ms was retained in the sorbent, then the prevalence would be 86%. This potentially indicates that it would be advantageous to prevent SO ₂ emissions later in the combustion process.

Unfortunately, because particles of this size have the opposite effect on ash deposition, it may not be possible to use absorbent particles of this size under certain conditions. To overcome this problem, experiments were carried out with larger calcium carbonate particles of 25 μm diameter. The Ca: S ratio was also reduced so that the absorbent could be utilized more efficiently. At 900 ° C., SO ₂ levels increased from 1350 ppm to 1500 ppm combustor midpoint levels and decreased to a final level of 1000 ppm at the end of the furnace. . This indicates that the absorbent is reasonably effective at the beginning of combustion, but gradually becomes more effective from about 800 ms after combustion. Calcium carbonate was not completely calcined up to this point in the combustion furnace and it is possible that it has released calcium oxide later in the process. Another possibility is that the sorbent breaks down over time, increasing the surface area over which absorption occurs. Since the average particle size of the ash particles is 19 μm, the initial size of the absorbent particles is 25 μm, but it is considered that the particles are somewhat broken.

At 1100 ° C., the SO ₂ level steadily drops from 2000 ppm to 1300 ppm. At this temperature the calcium carbonate should have been completely calcined in the first 200 ms of combustion. From this it is believed that the flame temperature is too high for significant absorption and SO ₂ absorption occurs after the absorbent has further exited the combustion furnace. The reactivity of the absorbent is highly dependent on the maximum temperature of the particles, and if the particle temperature becomes too high, the absorbent loses its reactivity or becomes "non-combustible". Average particle size is 1
Since it is 9 μm, the particles may be broken in DTF.

Ash samples taken when 25 μm calcium carbonate particles were used at 900 and 1100 ° C. have 10% and 5% calcium as sulfate, respectively.
This means that when comparing 900 ° C and 1100 ° C, D
This means that SO ₂ generation amount was reduced by 50% and 30%, respectively, at the exit of TF. It seems that the lower the temperature conditions, the more effective the SO ₂ absorption.

To confirm that the absorbent was completely calcined in DTF, the ash sample was placed on a thermobalance at 1200
Heat at 30 ° C. for 30 minutes. If the calcium carbonate still remained, it would be indicated by mass loss as it decomposes. From the results shown in Table 3, it can be seen that almost all the absorbent was fired in DTF.

[0052]

[Table 1]

[0053]

[Table 2]

[0054]

[Table 3]

Example 2 The test is a commercial calcium carbonate powder with an average size of 5 μm (ultrafine powder grade manufactured by Ben Bennett Jr.).
Was carried out in a laboratory combustor (LCR) using Neuhof emulsion fuel with addition of. L
The CR is a 350 KW petroleum combustor in which a gas atomized fuel spray is burned under the same conditions as an industrial boiler.
Table 1 shows the inspection data for Neuhoff base oil. The emulsion was prepared by the method described in EP 0156486B1. For testing purposes, the absorbent was premixed with water and surfactant into a slurry and then added into an 85:15 oil / water emulsion to give the final C
An emulsion of 30% water with an a: S molar ratio of 1: 1 was obtained.

The tests were carried out under a series of conditions for heat load and flue gas excess oxygen. Solid samples were taken to assess the sorbent availability level, while flue gas SO
A decrease of ₂ was measured using a conventional analyzer.

It has been found that the fuel / absorbent mixture burns without difficulty in ignition or flame stability. The results are summarized in Table 4. 5 in most of the tested conditions
The result that the SO ₂ reduction rate of 0% or more was achieved could be obtained. At the lowest excess oxygen (0.6%), the reduction was low (39%), probably due to the high flame and exhaust gas temperatures.

[0058]

[Table 4]

[0059]

The fuel composition according to the present invention is produced by adding, for example, calcium carbonate particles as a solid sulfur absorbent to an oil / water emulsion obtained by emulsifying a high-viscosity crude oil with a nonionic surfactant and dispersing the oil / water emulsion. .. This emulsion fuel composition has an effect that SO ₂ generated during combustion is absorbed by a solid sulfur absorbent to reduce the amount of SO ₂ in exhaust gas, and the reduction rate reaches 50% or more.

The fuel composition according to the present invention does not require separate injection of the sulfur absorbent into the combustion furnace or flue because the solid sulfur absorbent is incorporated into the emulsion fuel composition itself, and is costly. It has the advantage of being inexpensive and requiring no special equipment.

The fuel composition according to the present invention allows the solid waste produced to be easily collected by an ordinary apparatus, does not require further desulfurization treatment of the flue gas in order to comply with legal regulations, and can be used on a small scale. It has the advantage that it is very advantageous for the person.

[Brief description of drawings]

FIG. 1 is a graph showing the results of Example 1, showing SO ₂ absorption in exhaust gas by calcium carbonate in an emulsion fuel.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ji-yong Fritz Pryday 18 3 Tayda Brieu, England UK 3rd, Middlesets, Staines, The Hides No. 23 (72) Inventor David Chez Newey UK, gu 17 8pee , Surrey, Kiambury, Sandhurst, Ritsuplesmore Clause No. 3 (72) Inventor Gearless William Oscam United Kingdom, ARGIE 116 GE, Berkshire, Crowthorne, Oaklands Lane, Ranley Dell (No Address) (72) Invention Person Alan Stotskwell gu, England 12 2 Eldee, Surrey, Walking, Knutuphill, Raven's Claus 7

Claims (9)

[Claims] 1. An oil-in-water emulsion comprising 50-90% by volume of sulfur-containing petroleum having an API specific gravity in the range of 5-25 ° and 50-10% by volume of an aqueous solution of an emulsifying surfactant. In a fuel oil composition, the volume percentage of which is shown as a percentage of the total volume of both liquid phases and the oil droplets have an average droplet size in the range of 2-50 microns, the emulsion further comprises a solid sulfur absorbent. Alkaline earth metal oxides, hydroxides, carbonates or bicarbonates in the form of solid particles, the solid particles having an average diameter in the range of 2 to 50 microns and the alkaline earth in the solid Molar ratio of metal to sulfur in petroleum from 0.2: 1 to 5: 1
The fuel oil composition is present in an amount such that 2. The emulsion comprises 6 viscous petroleum containing sulfur.
40-25 of an aqueous solution of 0-75% by volume and an emulsifying surfactant
The fuel oil composition according to claim 1, wherein the fuel oil composition contains 100% by volume. 3. The fuel oil composition according to claim 1-2, wherein the oil droplets have an average droplet diameter in the range of 5-30 microns. 4. The alkaline earth metal oxide, hydroxide, carbonate or bicarbonate solid particles have an average diameter in the range of 5 to 30 microns.
The fuel oil composition according to claim 1. 5. The molar ratio of alkaline earth metal in the solid to sulfur in petroleum is in the range of 0.5: 1-3: 1. A fuel oil composition according to item. 6. The solid sulfur absorbent is calcium hydroxide,
The fuel oil composition according to any one of claims 1 to 5, which is magnesium carbonate or magnesium oxide. 7. The fuel oil composition according to any one of claims 1 to 5, wherein the solid sulfur absorbent is calcium carbonate. 8. The fuel oil composition according to any one of claims 1 to 7, wherein the emulsifying surfactant is a nonionic surfactant. 9. The nonionic surfactant is used in an amount of 1 per molecule.
The fuel oil composition according to claim 8, which is an ethoxylated alkylphenol containing 5-45 ethylene oxide groups.