KR900004547B1 - A process for the production and burning of a natural-emulsified liquid fuel - Google Patents

Abstract

A process for the prodn. of a natural liquid fuel for burning comprises (a) forming an oil in water emulsion from a bitumen crude oil, the bitumen crude oil having a viscosity of 1,4005,100,000 cSt at 50 deg.C., the oil in water emulsion being formed down hole in a well by injecting a mixture comprising water and emulsifier additive into the well to form the emulsion, the emulsion having a droplet size of 10-60 micron m, (b) pumping the oil in water emulsion from the well, and (c) adjusting the alkali metal content of the emulsion so that the emulsion has an alkali metal content of at least 50 ppm.

Description

Preparation and Combustion Method of Natural Emulsified Liquid Fuel

1 is a schematic diagram illustrating a process of the present invention.

2 is a graph showing the typical droplet size of an oil-in-water emulsion.

3 is a graph showing a comparison of sulfur dioxide emissions of the oil-in-water emulsion of the present invention and fuel oil No. 6.

4 is a graph showing a comparison of sulfur trioxide emissions from the oil-in-water emulsion of the present invention and No. 6 fuel oil.

The present invention relates to a method for producing a natural liquid fuel, and more particularly, a method for converting natural sulfur fuel into high energy by a combustion method that significantly reduces the amount of sulfur oxides emitted.

Natural bitumen, found in Canada, the Soviet Union, the United States, China and Venezuela, is typically a liquid with a viscosity of 10,000 to 200,000 CP and an API specific gravity of less than 10. Such natural bitumen has recently been produced by mechanical pumping, steam spraying or mining techniques. The widespread use of these materials as fuels has been hampered for a variety of reasons, including manufacturing, raw material transport and handling difficulties, and, more importantly, high sulfur oxide emissions and inadequate combustion characteristics including non-combustible solids. For this reason, natural bitumen has not been successfully used commercially as a fuel because of the high costs associated with the steam injection, pumping and desulfurization of flue gas necessary to overcome these difficulties.

Naturally, it has become extremely desirable to be able to use the natural bitumen of this form as a natural fuel.

Thus, the main object of the present invention is to provide a method for producing a natural liquid fuel from natural bitumen.

A special object of the present invention is to prepare a natural liquid fuel from the natural bitumen by forming an oil-in-water emulsion of the natural bitumen.

It is yet another object of the present invention to provide an oil-in-water emulsion used as a liquid fuel having properties for optimizing the combustion process.

It is a further object of the present invention to obtain excellent combustion efficiency, low non-combustion particulate solids and low sulfur oxide emissions by providing optimum combustion conditions for burning oil-in-water emulsions of natural bitumen.

Further objects and advantages of the present invention are described below.

The present invention relates to a method for producing natural liquid fuel, and more particularly, a method for converting natural sulfur natural fuel into energy by a combustion method that significantly reduces sulfur oxide emissions.

의 물 함량, 약 10 내지 60㎛의 액적 크기 및 50ppm이상, 적합하기로는 약 50 내지 600ppm의 알칼리금속 함량을 가져야 한다. 유화제는 수중유 에멀젼 중에 수중유 에멀젼의 전체중량에 기초해서 0.1 내지 5중량%의 양으로 존재하는 것이 적합하다.According to the present invention a downhole oil-in-water emulsion is formed by spraying a mixture of water and emulsifier into a well. U.S. Patent No. 3,467,195 to McAuliffe et al. Describes a suitable method for forming a downhole oil-in-water emulsion suitable for use in the methods of the present invention and is referred to herein. The amount of water in the emulsifier sprayed into the wells is adjusted to form an oil-in-water emulsion with specific properties for water content, droplet size and alkali metal content. In order to optimize the combustion characteristics of oil-in-water emulsions by the features of the present invention, oil-in-water emulsions with downholes having a volume of 15 to 38

Should have a water content, a droplet size of about 10 to 60 μm and an alkali metal content of at least 50 ppm, suitably about 50 to 600 ppm. The emulsifier is suitably present in an oil-in-water emulsion in an amount of from 0.1 to 5% by weight, based on the total weight of the oil-in-water emulsion.

The downhole oil-in-water emulsion is then pumped by a downhole deep pump known in the art to a flow station capable of degassing as needed. The oil-in-water emulsion is then sent to a combustion station. The water content, droplet size and alkali metal content in the oil-in-water emulsion at the combustion station are adjusted to achieve optimum combustion conditions. After being adjusted, the oil-in-water emulsion has a water content of 15 to 35% by volume, a droplet size of 10 to 60 μm and an alkali metal content of about 50 to 600 ppm. The emulsion is then subjected to the following conditions: 20 to 80 ° C., suitably 20 to 60 ° C. combustion temperature, 0.05 to 0.5 wt%, suitably 0.05 to 0.4 wt% steam / fuel ratio, 0.05 to 0.4 wt% Suitably, an air / fuel ratio of 0.05 to 0.3% by weight and a vapor pressure of about 1.97 to about 5.92 atmospheres (2 to 6 bar), suitably about 1.97 to about 3.95 atmospheres (2 to 4 bar) or about 1.97 to about 6.91 atm (2 to 7 bar), suitably for combustion under air pressure of about 1.97 to about 3.95 atm (2 to 4 bar).

Oil-in-water emulsions prepared by the process of the invention by the present invention are controlled by the present invention and, when burned under controlled operating conditions, have a combustion efficiency of 99.9%, low particulate solids content and conventional No. 6 fuel. You get sulfur oxide emissions that match the emissions from burning oil.

The method of the present invention is described with reference to FIG. A well 10 having a downhole deep pump is supplied with water and an emulsifier to form an oil-in-water emulsion that can be pumped from the well 10 by a deep pump and sent out through the pipe 12 to the degassing station 14. do. The degassed oil-in-water emulsion is then stored in storage zone 16 for subsequent transportation by means 18 such as tankers, trucks, pipelines. The oil-in-water emulsion, once transported, may be stored in storage zone 20 and / or sent to control zone 22 and adjusted before being burned in combustion zone 24.

By the present invention, the process of the present invention can produce and burn natural fuel obtained from wells. Suitable fuels for the process of the invention are bitumen crude oils of high sulfur content, such as the typical crude oil found in the Orinoco range of Venezuela. Bitumen crude oil has the following chemical and physical properties. That is, 78.2 to 85.5 weight percent C, 10.0 to 10.8 weight percent H, 0.26 to 1.1 weight percent O, 0.50 to 0.66 weight percent N, 3.68 to 4.02 weight percent S, 0.05 to 0.33 weight percent ash, 420 to 520 ppm vanadium, 90 to 120 ppm nickel, 10 to 60 ppm iron, 60 to 120 ppm sodium, 1.0 to 12.0 API specific gravity, 1,400 to 5,100,000 viscosity (CST, 50 ° C.) or 70 to 16,000 viscosity ( CST, about 99 ° C.), LHV (dl / kg) of 8500 to 10,000, and asphaltenes of 9.0 to 15.0% by weight. According to the invention, a mixture of water and emulsifier is injected into the well to form an oil-in-water emulsion pumped from the well by a downhole deep pump. An important feature of the present invention is that the properties of oil-in-water emulsions are best suited for the transport and combustion of oil-in-water emulsions. The oil-in-water emulsion obtained from the wells has a water content of about 15 to 35% by volume, suitably about 20 to 30% by volume, about 10 to 60 μm, suitably droplet sizes of about 40 to 60 μm, at least 50 ppm, Is characterized by having an alkali metal content of about 50 to 600 ppm. It has been found that the alkali metal concentration in the oil-in-water emulsion has a large influence on the amount of gaseous emissions during emulsion combustion.

By spraying water, water is produced together with the bitumen crude in the bitumen crude oil manufacturing process. The analysis results of the generated water found in Orinoco University are shown in Table I below.

TABLE I

As can be seen from Table 1, the produced water contains significant amounts of alkali metals (Na ⁺ and K ⁺ ). Oil-in-water emulsions prepared by controlling the amount of water and alkali metal content sprayed with the emulsifier can have the desired alkali metal and water content as described above. As mentioned above, the water to be sprayed contains an emulsifier additive. The emulsifier is added in an amount of about 0.1 to 5.0% by weight, suitably about 0.1 to 1.0% by weight, based on the total weight of the resulting oil-in-water emulsion. The emulsifier added by the present invention is selected from the group consisting of anionic surfactants, nonionic surfactants, cationic surfactants, mixtures of anionic surfactants and nonionic surfactants, and mixtures of cationic surfactants and nonionic surfactants. Suitable nonionic surfactants for use in the present invention are selected from the group consisting of ethoxylated alkylphenols, ethoxylated alcohols, ethoxylated sorbitan esters and mixtures thereof. Suitable cationic surfactants are selected from the group consisting of hydrochlorides of fatty diamines, imidazolines, ethoxylated amines, imido-amines, quaternary ammonium compounds, and mixtures thereof, while suitable anionic surfactants are long chain carboxylic acids, Sulfonic acid and mixtures thereof. More suitable surfactants are nonionic surfactants having at least 13 hydrophilic-lipophilic equilibria, such as nonylphenols oxyalkylated with 20 ethylene oxide units. More suitable anionic surfactants are selected from alkylaryl sulfonates, alkylaryl sulfates and mixtures thereof.

The water additive mixture sprayed into the wells stabilizes the oil-in-water emulsion. The water injected depends on the product water produced with the bitumen. The salt content also depends on the desired bitumen water ratio suitable for handling and burning, and finally depends on the emulsifier form and the amount of emulsifier. At this stage the fuel is formulated to have properties suitable for handling and burning. Once the emulsion is formed and pumped out of the well, it can be degassed without many problems due to the low viscosity of the emulsion. In this case, it is not necessary to heat before separating the gas as in the case where only bitumen must be degassed.

The emulsion can then be stored for storage, pumped through the flow station and the main station, and additives such as imidazoline can be added to prevent corrosion of the metal walls due to the presence of water. By installing an on-line mixer at any stage (after degassing, before pumping through an oil pipeline or shipping to an oil tanker, etc.), a good emulsion with any suitable droplet size distribution as described above can be ensured.

Once the oil-in-water emulsion is transferred to the combustor, the emulsified fuel is adjusted to optimize the water content, droplet size and alkali metal content of the oil-in-water emulsion. The regulator consists of an on-line mixer and an alkali metal concentration regulator. The purpose of the online mixer is to control the average droplet size of emulsified liquid fuel. Droplet size distributions have a significant impact on combustion in the combustion characteristics of this natural fuel, in particular in terms of flow control and heat loss. The size distribution of the droplets immediately before and after the on-line mixer is shown in FIG. It can be seen from FIG. 2 that the average droplet size was reduced from 65 μm to 51 μm. Also, it can be seen from FIG. 2 that the droplet size distribution is evenly distributed. In other words, a bell-shaped distribution curve is achieved. Oil-in-water emulsions according to the present invention should have a droplet size of about 10 to 60 μm.

In addition, the alkali metal content in the oil-in-water emulsion has been found to have a significant effect on the combustion characteristics of the emulsion, especially sulfur oxide emissions. It has a positive effect in reducing alkali metal sulfur dioxide emissions such as sodium and calcium. Due to the large interfacial bitumen surface-to-volume ratio, it is believed to react with sulfur compounds present in alkali metal natural fuels to produce alkali metal sulfides such as sodium sulfide and potassium sulfide. During combustion, the sulfide is oxidized to sulphate to fix the sulphate to the combustion ash, thus preventing sulfur from being released into the atmosphere as part of the flue gas. As mentioned above, the alkali metal is already added to the emulsion in the production of the natural fuel emulsion by the natural mixing of the alkali metal contained in the product water. If the alkali metal concentration in the emulsion fuel is not optimal, some additional amount may be added to the emulsion in the alkali metal concentration regulator. This is done by adding synthetic aqueous solution of produced water, brine or alkali metal. According to the present invention, oil-in-water emulsions should have an alkali metal content of at least 50 ppm, suitably about 50 to 600 ppm, ideally 50 to 300 ppm.

Once the oil-in-water emulsion is adjusted, it is ready for combustion. Conventional oil spray burners such as internal mixing burners or hyperbolic sprayers can be used. It is suitable to spray with steam or air under the following operating conditions: That is, a fuel temperature of 20 to 80 ° C., suitably 20 to 60 ° C., 0.05 to 0.5, suitably a steam / fuel ratio (weight / weight) of 0.05 to 0.4, 0.05 to 0.4, suitably 0.05 to 0.3 air / Fuel ratio (weight / weight) and about 1.48 to 5.92 atmospheres (1.5 to 6 bar), suitably vapor pressures of about 1.97 to about 3.95 atmospheres (2 to 4 bars) or about 1.97 to 6.91 atmospheres (2 to 7 bars) Suitably spraying under an air pressure of about 1.97 to about 3.92 atmospheres (2 to 4 bar). Good atomization and efficient combustion are obtained with good flame stability under these conditions.

The advantages of the invention will be apparent from the following non-limiting examples.

Example 1

Two emulsions were prepared having the properties described in Table II (also described as Orinoco Bitumen) to demonstrate the effect on the combustion characteristics of oil-in-water emulsions of alkali metal concentrations compared to Orinoco Bitumen. Sodium was used as the alkali metal.

TABLE II

All fuels were burned under the operating conditions described in Table III below.

TABLE III

Gaseous emissions and combustion efficiencies for each fuel are listed in Table IV below.

TABLE IV

The results indicate an increased combustion efficiency, i.e., 99.0% to 99.9%, for the emulsified Orinoco bitumen over the Orinoco raw bitumen. In addition, it can be seen from the comparison result of emulsion # 1 and emulsion # 2 that the sulfur oxide emissions, that is, SO ₂ and SO ₃ are reduced with increasing alkali metal (sodium) concentration.

Example 2

The effect of operating conditions on the combustion characteristics of various fuels was studied. Table V below compares Orinoco bitumen with eight oil-in-water emulsions.

TABLE V

Orinoco bitumen and emulsions # 3, # 6, # 7 and # 10 were sprayed with steam. Emulsions # 4, # 5, # 8 and # 9 were sprayed with air. Sodium was used as alkali metal in emulsions # 3, # 4, # 5 and # 6, while potassium was added in emulsions # 7, # 8, # 9 and # 10. The operating conditions are listed in Table VI below.

Table VI

Combustion efficiency and gaseous emissions are listed in Table VII below.

TABLE VII

The results show that when burning an emulsion containing an alkali metal, not only the drastic reduction of sulfur oxides but also the efficiency is increased. In addition, the lower the air / fuel ratio, the lower the sulfur oxides. The same result will be obtained at lower steam / fuel ratios. Finally, the amount of nitrogen oxides was also reduced. Compared to Orinoco crude oil, the operating conditions when burning emulsified fuels were generally less stringent. That is, fuel spray, fuel temperature and pressure were lower, and operational flexibility was added by using air or steam. Reduction of sulfur oxide emissions is an important feature of alkali metal-containing oil-in-water emulsions. The release of sulfur trioxide causes so-called cold-end corrosion which concentrates sulfuric acid in the cooler section of the boiler (air heaters and economizers). In addition, sulfur trioxide is a source of ash acid in electric dust collectors and other solid collectors.

Example 3

Sulfur emissions of emulsion # 3 of Example 2 were compared with those of No. 6 fuel oil, and the results are shown in FIGS. 3 and 4. From these results, sulfur oxide emissions of oil-in-water emulsions were advantageous over No. 6 fuel oil and much better than Orinoco bitumen. SO ₂ emissions from oil-in-water emulsions were 33% lower than No. 6 fuel oil and 66% lower than Orinoco Bitumen. In addition, sulfur trioxide emissions were also lower in emulsion # 3 compared to No. 6 fuel oil (2.5% S) and Orinoco bitumen. That is, SO ₃ emissions of oil-in-water emulsions were reduced by 17% and 50%, respectively, compared to No. 6 fuel oil and Orinoco bitumen.

Claims (21)

(a) forming an oil-in-water emulsion, (b) adjusting the content of alkali metal in the emulsion to at least about 50 ppm, and (c) burning the oil-in-water emulsion as fuel. Process for producing and burning natural liquid fuels. The method of claim 1, wherein the water content is about 15 to 35% by volume, the droplet size is about 10 to 60㎛ by spraying a mixture of water and emulsifier additive in the well to form the emulsion downhole in the well A water-in-oil emulsion having a content of at least 50 ppm. 3. The method of claim 2, further comprising: pumping the oil-in-water emulsion from the well to a flow station, transferring the oil-in-water emulsion from the flow station to a combustion station, water content of the oil-in-water emulsion, droplet size and alkali metal Adjusting the oil-in-water emulsion so that its content meets the optimum combustion conditions and burning the optimized oil-in-water emulsion so that sulfur dioxide and sulfur trioxide emissions are significantly reduced than that of No. 6 fuel oil. How to feature. The method of claim 3, wherein the alkali metal content is about 50-600 ppm. The method of claim 1, wherein the bitumen crude oil has the following chemical and physical properties. C, 78.2 to 85.5%, H, 10.0 to 10.8%, O, 0.26 to 1.1%, N, 0.50 to 0.66%, S, 3.68 to 4.02%, Ash, 0.05 to 0.33%, Vanadium, 420 to 520 ppm, nickel, 90 to 120 ppm, iron, 10 to 60 ppm, sodium, 60 to 200 ppm, API specific gravity, 1.0 to 12.0, viscosity (CST), 1,400 to 5,100,000, 99 ° C (210 ° C) at 50 ° C (122 ° F) 70-16,000, LHV (dl / kg), 8,500-10,000, asphaltenes, 9.0-15.0 wt%. 3. The method of claim 2 wherein said emulsifier additive is selected from the group consisting of anionic surfactants, nonionic surfactants, cationic surfactants, and mixtures of cationic and nonionic surfactants. 7. The method of claim 6, wherein said nonionic surfactant is selected from the group consisting of ethoxylated alkyl phenols, ethoxylated alcohols, ethoxylated sorbitan esters, and mixtures thereof. 7. The method of claim 6, wherein said cationic surfactant is selected from the group consisting of hydrochlorides of fatty diamines, imidazolines, ethoxylated amines, amido-amines, quaternary ammonium compounds, and mixtures thereof. 7. The method of claim 6, wherein said anionic surfactant is selected from the group consisting of long chain carboxylic acids, sulfonic acids and mixtures thereof. The method of claim 2 wherein said emulsifier additive is a nonionic surfactant having a hydrophilic-fat affinity equilibrium of at least 13. The method of claim 10 wherein the nonionic surfactant is nonylphenol oxyalkylated with 20 ethylene oxide units. 10. The method of claim 9, wherein said anionic surfactant is selected from the group consisting of alkylaryl sulfonates, alkylaryl sulfates, and mixtures thereof. The method of claim 2 wherein the emulsifier additive is present in an amount of about 0.1 to 5 weight percent based on the total weight of the oil-in-water emulsion. The method of claim 1 wherein the oil-in-water emulsion has a water content of 20-30% by volume, an average droplet size of 40-60 μm, and an alkali metal content of 50-600 ppm. 4. The method of claim 3, wherein the oil-in-water emulsion is degassed prior to adjusting to the combustion conditions. 4. A method according to claim 3, wherein a corrosion inhibitor is added to the oil-in-water emulsion prior to transfer as above. 4. The oil-in-water emulsion according to claim 3, wherein the oil-in-water emulsion is adjusted to obtain an oil-in-water emulsion having a water content of about 20-30% by volume, a droplet size of about 10-60 µm and an alkali metal content of about 50-300 ppm. Way. 4. The method of claim 3, wherein the optimized oil-in-water emulsion is combusted under the following operating conditions. Fuel temperature; 20 to 80 ° C., steam / fuel ratio (weight / weight); 0.05 to 0.5, air / fuel ratio (weight / weight); 0.05 to 0.4 and vapor pressure; About 1.97 to 5.92 atmospheres (2 to 6 bar) or air pressure; About 1.97 to 6.91 atmospheres (2 to 7 bar). The method of claim 3 wherein the optimized oil-in-water emulsion is combusted under the following operating conditions. Fuel temperature; 20 to 60 ° C., steam / fuel ratio (weight / weight); 0.05 to 0.4, air / fuel ratio (weight / weight); 0.05 to 0.3 and vapor pressure; About 1.97 to 3.95 atmospheres (2 to 4 bar) or air pressure; About 1.97-3.95 atmospheres (2-4 bar). 4. The method of claim 3, wherein the fuel sulfur in the solid combustion product is chemically fixed to drastically reduce the emissions of sulfur dioxide and sulfur trioxide emitted from the combustion of the optimized oil-in-water emulsion. A natural liquid fuel in the form of an oil-in-water emulsion prepared from bitumen crude oil having a water content of about 15 to 35% by volume and an alkali metal content of at least about 50 ppm.

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