EA013093B1 - Method for producing water-fuel emulsion and composite multi-component fuel - Google Patents

Abstract

The invention relates to a method for producing hydrocarbon fuel in use as technological fuel at industrial enterprises, e.g. at thermal electric plants, metallurgical and chemical plants and other heat-consuming facilities and can be used for fuel production from watered fuel oil, burner fuel, oil-slimes, heavy residual fractions of oil processing and also from resin oils with simultaneous use of waters contaminated by hydrocarbons. The inventive method is aimed at simplification thereof, providing to produce high-quality water-fuel emulsion and composite multi-component fuel from a hydrocarbon raw feedstock – fuel oil, burner fuel, oil-slimes, heavy residual fractions of oil processing and also from resin oils with simultaneous use of waters contaminated by hydrocarbons and excluding the use of gaseous hydrocarbons which leads to the method effectiveness. According to the invention the method for producing water-fuel emulsion and composite multi-component fuel comprises heating of initial hydrocarbon raw feedstock and pressurized processing in an emulsifying unit, the initial hydrocarbon raw feedstock with water content up to 50% is heated to 50-120°C and subjected to cavitation treatment at up to 50 atm. pressure to form fine-dispersed water-fuel emulsion comprising 0.5-5.0 mkm particles.

Description

The invention relates to the production of hydrocarbon fuel used as process fuel in industrial enterprises, in particular thermal power plants, metallurgical plants, chemical plants and other heat-consuming structures, and can be used to obtain fuel from flooded fuel oil, heating oil, oil sludge, heavy residual fractions oil refining, as well as coal oils and resins with the simultaneous utilization of produced water contaminated with hydrocarbons.

A known method of producing gas oil fuel for heating a steel-smelting furnace, comprising replacing part of the supplied fuel oil with water and obtaining a water-oil emulsion, supplying combustible gas, for example natural, obtained oil-oil emulsion, fan and compressor air and technical oxygen to the burner device, burning flammable components and removal of combustion products. A water-oil emulsion is obtained by supplying fuel oil and water to a rotary device for hydroacoustic treatment of liquids, containing a blade impeller in the form of a bearing and covering discs with a peripheral annular wall provided with a number of outlet openings and an annular resonant ring formed by the peripheral annular wall of the impeller and a continuous coaxial wall of the stator cavity communicated with the precast chamber. The water content in the water-oil emulsion is regulated depending on the temperature and emissivity of the torch so that they are maintained at least at the level of temperature and emissivity of the torch when operating on clean fuel oil. The viscosity of the oil-water emulsion is reduced depending on the water content by increasing the temperature of the oil-oil emulsion at the inlet of the burner so that it remains at least at the level of viscosity of the fuel oil when working on clean fuel oil (RF patent No. 2253798, class P23C 1/00, 2005).

The disadvantage of this method is the need for an additional supply of combustible gas, for example natural, as well as technical oxygen, which complicates the process of obtaining fuel.

A known method of producing a fuel emulsion and multicomponent composite fuel from fuel oil, comprising mixing heated mazut brand M100 and / or M40 and stabilized gas condensate, in which heating oil is heating oil with a temperature of 50 ° C and stabilized gas condensate with a temperature of 20 ° C under a pressure of up to 3 atm in a predetermined proportion is fed into the mixing chamber of the components, then the resulting mixture enters the emulsifying device, where it is subjected to ultrasonic treatment to obtain thin from the fuel mixture dispersed emulsion, and subsequent mixing of two or more streams of finely dispersed emulsion of the fuel mixture with a constantly maintained temperature of 50-60 ° C in the intensive mixing chamber due to the organization of mixing by counter flows under pressure and transportation of the finished product in storage tanks, combined by a circulation system, exposing the finished product constant circulation under pressure up to 2 atm and passing through an emulsifying device (RF patent No. 2278149, class. C10 1/04, 2006).

This method provides for the production of a fuel emulsion and multicomponent composite fuel from fuel oil and stabilized gas condensate and does not allow to obtain fuel only from heavy oil residues. This reduces the efficiency of the method and its availability, complicates the process of obtaining fuel and increases material costs and labor costs for implementation. The need to include stabilized gas condensate in the fuel narrows the technological capabilities of the method, since its implementation is possible only at those facilities where there is gas condensate.

The objective of the invention is to develop a method for producing hydrocarbon fuel from waterlogged oil residues generated during oil refining, which allows to reduce material costs and labor costs for the implementation of the method, as well as to ensure its availability.

EFFECT: simplification of the method, provision of the possibility of obtaining high-quality water-fuel emulsion and composite multicomponent fuel from hydrocarbon raw materials - fuel oil, heating oil, oil sludge, heavy residual fractions of oil refining, as well as coal oils and resins with simultaneous utilization of produced water contaminated with hydrocarbons, and the exception the need for the introduction of gaseous hydrocarbons, which increases the efficiency of the method.

This result is achieved by the fact that in the method for producing a water-fuel emulsion and composite multicomponent fuel, comprising heating the feedstock and processing under pressure in an emulsifying device according to the invention, the feedstock with a water content of up to 50% is heated to a temperature of 50-120 ° C and subjected to cavitation treatment under pressure up to 50 atmospheres to form a finely dispersed water-fuel emulsion containing water particles with a size of 0.5-5.0 microns.

The proposed method allows the production of high-quality fuel from hydrocarbon raw materials - fuel oil, heating oil, oil sludge, other heavy residual fractions of oil refining, as well as coal oils and resins and commercial water contaminated with oil products, significantly superior to operational fuel oils. The resulting emulsion forming a composite multicomponent fuel remains stable for more than 12 months, since

- 1 013093 the pergeneration of water and fuel oil occurs at a pre-molecular level.

The particle size of water of 0.5-5.0 μm is optimal, with such parameters of the particles, the surface tension forces are sufficient to maintain a stable dispersion of the medium for a long time. In addition, the claimed particle size provides the necessary degree of atomization of the fuel. With a decrease in the particle size of water below 0.5 μm, the vapors generated from it during combustion of a water-fuel emulsion do not have enough energy to break the surrounding hydrocarbon shell and provide a secondary atomization process. With an increase in the particle size of water more than 5.0 μm, the required stability and high efficiency during combustion are not achieved.

The use of a fuel-oil emulsion obtained in accordance with the proposed method will increase the overhaul time for servicing boiler equipment up to 40%; significantly reduce environmentally harmful emissions into the environment of industrial regions by up to 80%, and by some indicators by an order of magnitude. In addition, it ensures the complete utilization of water contaminated with oil products and saves (up to 30%) expensive hydrocarbon fuels.

In modern conditions of operation of boiler plants and process furnaces during the burning of fuel oil and heating oil, maintenance personnel encounter a number of problems that not only affect the reliability of the heating equipment, but also lead to an excessive consumption of fuel, a decrease in the technical and economic performance of the equipment and grade of products pollution of the environment (gas contamination of the air basin and pollution of the soil and water bodies with waste water containing oil products).

The most common problems when using fuel oil are as follows.

1. Flooding of fuel oil. When unloading, transporting, storing and maintaining in a hot reserve, fuel oil is saturated with water. Inclusions of water in modern "heavy" fuel oils practically do not settle and cannot be removed from fuel oil by traditional methods. At the same time, water in the form of lenses or bags is unevenly distributed over the entire mass of fuel oil, which leads to a significant deterioration in the conditions of its combustion.

2. Deterioration in the quality of the source fuel oil. Due to a change in the technology of oil refining in order to obtain more light fractions, the quality of fuel oil decreases, in particular, its viscosity and flash point increase. The use of viscous and heavy fuel oils is fraught with significant difficulties, both during storage and when spraying for burning.

3. The "aging" of fuel oil. During long-term storage with the practice of maintaining fuel oil in a hot reserve, light fractions evaporate from it, which leads to an increase in its viscosity and flash point. As a rule, after 2-3 years of storage, the burning of such fuel oil becomes impossible and it must be replaced with more fresh fuel oil.

4. Deterioration of equipment and insufficient technical equipment of fuel burning plants. In some cases, the technical condition of the fuel oil preparation system does not allow heating the fuel oil to the temperature necessary for burning at least 90 ° C. This leads to the fact that the nozzles do not provide the necessary spray of fuel oil. And this, in turn, leads to a large chemical and mechanical underburning of the fuel (soot), an excess supply of air for combustion, and, ultimately, to a decrease in the efficiency of the equipment and excessive consumption of fuel oil.

5. Low-temperature sulfuric acid corrosion of metal surfaces of smoke paths.

6. Environmental pollution by the combustion products of fuel oil (carbon oxides, sulfur and nitrogen, soot, benz (a) pyrene) and waste waters containing petroleum products.

One of the most effective and low-cost ways to solve these problems is to modify heavy fuel oil and other oil refinery wastes in order to obtain a homogeneous water-fuel emulsion and to burn this emulsion in boiler furnaces and process furnaces. An essential requirement for an emulsion, which substantially ensures the effectiveness of its use, is its dispersion. This characteristic reflects the size of water particles in the fuel. The best results are achieved when the dispersion of water particles from 0.5 to 5 microns.

In accordance with the proposed method, the feedstock, passing through a dispersant, is subjected to cavitation treatment, as a result of which the water present in the fuel is evenly distributed throughout the mass in the form of tiny particles with sizes from 0.5 to 5 microns, forming a homogeneous, highly stable and finely dispersed water-fuel emulsion . Preheating the feedstock to 50-120 ° C and a pressure of up to 50 atm make it possible to obtain an emulsion with such a particle size of water.

The invention is illustrated by drawings, where in FIG. 1 is a diagram for producing a water-fuel emulsion with a dispersant for processing the feedstock;

in FIG. 2 is a photomicrograph of the initial flooded fuel oil;

in FIG. 3 - micrograph of a fuel oil emulsion from fuel oil;

in FIG. 4 is a graph representing the dependence of the content of nitrogen oxides in the exhaust gases on the steam load when burning conventional fuel oil (I) and water-fuel emulsion (II);

in FIG. 5 is a graph representing the dependence of the sulfur dioxide content in the effluent

- 2 013093 gases from the steam load of the boiler, when burning ordinary fuel oil (I) and water-fuel emulsion (II);

in FIG. 6 is a graph of the specific fuel consumption for the generation of 1 Gcal of heat with optimal excess air from steam load during the combustion of ordinary fuel oil (I) and water-fuel emulsion (II);

in FIG. 7 is a graph of the dependence of the content of nitrogen oxides in the exhaust gases behind the superheater, reduced to an excess of air 1.4, on the steam load when burning ordinary fuel oil (I) and water-fuel emulsion (II);

in FIG. 8 is a graph of the dependence of the content of sulfur dioxide in the flue gases, reduced to an excess of air 1.4, on the load when burning ordinary fuel oil (I) and water-fuel emulsion (II).

The system for producing a fuel-oil emulsion includes a line 1 for collecting feedstock into a system of containers (not shown), filters 2, feed pumps 3 with the corresponding characteristics, an emulsifying device 4, pressure gauges for monitoring the performance and contamination of the emulsifying device 5, a sampler 6 for monitoring product quality, in-line hydrometer 7, pipe 8 for supplying steam to flush the emulsifying device 4, pipe 9 for draining condensate and deposits from the emulsifying device 4, line 10 for supplying additional components comrade (e.g., water, or waste oil), pumps 11, feeding additional components, dispensers 12 (flow) for adjusting the amount of additional components, the ducts 13 discharge the finished product.

The method is as follows.

Example 1

Fuel oil containing 50% water is heated to a temperature of 120 ° C and through line 1 through filters 2, pumps 3 are fed into an emulsifying device 4, for example a dispersant, under a pressure of 30 atm. The pressure in the system is checked using pressure gauges 5. The flow rate is 8-15 m / s. At the indicated speed and under the action of high pressure, the flow of the initial medium is accelerated and crushed using a cavitation grating (not shown) installed in an emulsifying device. When the flow is crushed and the plates are braked by a grid, a pressure drop occurs, due to which cavitation bubbles are formed, during the collapse of which shock waves are generated, which additionally destroy heavy hydrocarbon molecules and water particles. This leads to the formation of a finely dispersed water-fuel emulsion containing water particles with a size of 0.5-5 microns.

As a result of the intensive cavitation effect on the fuel, structural changes occur in it - long hydrocarbon chains “break”, the fuel becomes “lighter" and its thermophysical characteristics and rheological properties improve, and the solid particles contained in the fuel are destroyed and crushed. This is confirmed by the positive results of the conversion of boilers and drying ovens designed to burn diesel and light heating oil to work on low-grade dark heating oil.

To determine the quality of the finished product, samples are taken using a sampler 6. The finished product is taken through the nozzle 13. To clean the system, steam is used, which is supplied through line 8, the condensate formed and dirt is removed through line 9.

The process of burning the resulting water-fuel emulsion and composite fuel differs from the burning of raw fuel in the following. Micron droplets of water surrounded by a solvate shell of hydrocarbon fuel evaporate in a furnace heated to high temperatures with an explosion speed, water vapor “breaks” the surrounding fuel - a secondary atomization process occurs. As a result of this, many microdrops are formed from the initial fuel drop, the evaporation rate and the total area of chemical interaction of which with the blown air supplied to the furnace is many times higher. Due to this, a multiple reduction in the time of passage of oxidative reactions (complete combustion of fuel) is ensured and, accordingly, it is possible to significantly reduce the amount of air supplied to the combustion, which reduces heat loss with flue gases and significantly reduces mass emissions of harmful substances into the atmosphere. In addition, due to the high stability of the resulting water-fuel emulsions from the fuel preparation technology, the operations of sedimentation and discharge of produced water are excluded, which is also an important result in ensuring the environmental cleanliness of the facilities.

At the same time, reliable operation of boilers and process furnaces is guaranteed when the initial fuel water cut is up to 50% and high energy and environmental indicators are ensured when burning the emulsion obtained in the normal mode.

Comparative tests were carried out on a TGM-84 boiler unit at loads of 260, 290 and 320 t / h at a temperature of fuel oil supplied to the boiler equal to 110-114 ° С and a temperature of water-fuel emulsion equal to 90-95 ° С.

The analysis of the flue gas composition was carried out by a DAG-500 gas analyzer and was duplicated by a KGA-M type device behind the boiler (operating point), and also in front of smoke exhausters (balance point). Flue gas sampling was carried out using gas sampling tubes. The test duration was 40-60 minutes, the stability criteria of the newly established mode was the constancy of steam consumption,

- 3 013093 steam pressure in the line, flue gas temperature, as well as gas analysis. During the tests, boiler fuel oil of the M-40 brand and a water-oil emulsion (modified fuel oil) prepared from the same fuel oil were burned on the boiler. Fuel characteristics are presented in the table.

Steam consumption was determined by a shield flow meter. The fuel consumption for the boiler was determined by the reverse balance with the actual boiler gross efficiency, as well as by monitoring the change in the pressure of the fuel supply to the nozzles and according to the indications of the fuel oil shield meter.

The water mode of operation of the boiler was monitored on the basis of analyzes of feed and boiler water performed by the personnel of the chemical laboratory of the station.

The temperature of the feed water entering the economizer of the boiler during testing was 207-211 ° C (calculated value of 230 ° C).

The change in fuel consumption burned on the boiler was carried out by its pressure in front of the nozzles. Depression in the furnace of the boiler was maintained at a constant level (-1.5-2.0) kgf / m ² using guide vanes of smoke exhausters. The flow rate of the supplied air to the boiler furnace was controlled by the air pressure in front of the burners. Air flow control was carried out by guiding devices of the blower fans with fully open gates in front of the burners. For the optimum, a stable (stable) mode of fuel combustion was taken, without ripples. The optimal coefficient of excess air in the exhaust gases was selected from the following ratio:

and _opt = a _cr + (0.03-n0.04), where a _cr is the critical coefficient of excess air.

After determining the optimal excess air, tests were carried out to determine the parameters necessary for calculating heat loss with flue gases, with chemical incompleteness of combustion and into the environment, as well as the efficiency of the gross boiler unit.

During the comparative tests at the gas analysis sampling sites, measurements were made of the level of concentrations of harmful substances in the flue gases emitted into the atmosphere (carbon monoxide, nitrogen oxides and sulfur dioxide).

Carbon monoxide (CO).

During the work, almost complete combustion of fuel was organized in the combustion chamber of the boiler unit. When operating at optimal excess air, the concentration of products of incomplete combustion of fuel (CO) in flue gases does not exceed 50 mg / m, which corresponds to actual heat excess from chemical losses. unburned in 0.01% (permissible - 0.5%).

Nitrogen oxides (ΝΟ _Χ ).

During the experimental work, special attention was paid to the emissions of nitrogen oxides into the atmosphere with flue gases, since they are one of the most dangerous substances in terms of their toxic properties and harmful effects on humans. In practice, usually fixed amount of oxide and nitrogen dioxide emitted into the atmosphere, (ΝΟ + ΝΟ ₂ = ΝΟ _Χ).

Studies conducted during the combustion of fuel oil (humidity 1.0%) and emulsion with a moisture content of 16.0% showed that when switching to burning emulsion, the concentration of nitrogen oxides in the flue gases, resulting in an excess of air of 1.4, decreases. In FIG. Figure 7 shows the dependences of the concentration of nitrogen oxides reduced to excess air of 1.4 in the exhaust gases during the combustion of fuel oil (Schedule I) and water-fuel emulsion (Schedule II).

Sulfuric anhydride (8Ο ₂ ).

In FIG. Figure 8 shows the dependence of the content of sulfur dioxide in the flue gases, reduced to an excess of air 1.4, on the load when burning ordinary fuel oil (I) and water-fuel emulsion (II). As seen from the graph, the transition to combustion of water-fuel emulsions §Ο ₂ concentration in the flue gases is reduced.

When burning water-fuel emulsions, energy costs (traction and blasting) are reduced. An approximate calculation of the economic efficiency of this method is presented below.

Electricity for traction and blasting.

According to the results of processing the experimental data, it was revealed that at the same loads when switching to burning the emulsion obtained, on average, the energy consumption for driving fans and smoke exhausters decreases by 200 kW / h. With an average number of hours of operation of the boiler equal to 2160 hours per year, when burning liquid fuel, energy savings will be

DE = 200 kW-2160 h / year = 432000 kW-h / year

The heat savings due to lowering the temperature of heating the fuel from 120 ° C (fuel oil) to 95 ° C (water-fuel emulsion) will be as follows.

The average decrease in steam consumption for heating the emulsion compared to fuel oil was 1.18 t / h with the following steam parameters: pressure 10 kgf / cm ² and a temperature of 250 ° C. Accordingly, the vapor enthalpy is 1 = 703.2 kcal / kg.

The temperature of the condensate at the outlet of the heaters was 90 ° С, the enthalpy of water was 1 = 90.1 kcal / kg. Enthalpy difference: Δ = 703.2-90.1 = 613.1 kcal / kg.

- 4 013093

Annual heat savings will be

Δρ = (613.1 · 1.18-2160) / 1000 = 1562.67 Gcal / year.

The average reduction in the consumption of initial fuel oil during the transition to the combustion of a fuel-oil emulsion at average operating loads (250-270 t / h) was 300 kg / h.

Fuel oil savings for the year are ΔΕμ = 0.3-2160 = 648 t / year.

The above calculation shows the economic efficiency of using the resulting water-fuel emulsion by lowering the heating temperature to 95 ° C.

Water-fuel emulsion obtained in accordance with the proposed method guarantees the possibility of efficient operation of the burners when it is heated to 65-75 ° C. In this case, the steam consumption for heating will be even lower, which will provide additional heat savings due to lower fuel heating temperatures.

The ash content of the emulsion obtained in accordance with the proposed method is reduced from 0.095 to 0.021%, the mass fraction of sulfur is reduced from 2.3 to 1.5%, the calorific value is increased from 9688 to 10656 kcal / kg.

Example 2

The method is carried out as in example 1, but as a starting product using heating oil containing 20% of produced water. Waterlogged heating oil is heated to a temperature of 60 ° C and subjected to cavitation treatment under a pressure of 20 atm.

The resulting water-fuel emulsion during combustion provides a reduction in emissions of toxic substances such as sulfur and nitrogen oxides, which is confirmed by the graphs presented in FIG. 4-8.

With a small water content in the initial product, cavitation treatment can be carried out under a pressure of 6-10 atm, which also provides a high-quality emulsion.

Example 3

In the process of preparing a water-fuel emulsion in order to determine changes in the properties of the original fuel oil that occur during its cavitation treatment in an emulsifying device, laboratory studies of samples of the original fuel oil M-100 were carried out; source fuel oil passing through an emulsifying device; initial fuel oil with the addition of 22% water in the laboratory without cavitation treatment and the water-fuel emulsion MM-100 obtained after cavitation treatment with a water content of 19 and 32 wt.%. The results of laboratory studies of all these fuel samples are given in table. one.

Laboratory calorimetric studies of the highest and calculation of the lower calorific value of all these fuel samples showed that cavitation treatment of both the initial fuel oil and the high-water emulsion MM-100 provided a significant increase (in terms of dry fuel) to the values of the lowest calorific value from 42811 kJ / kg for “dry” fuel oil after cavitation treatment up to 58505 kJ / kg for a water-fuel emulsion with a moisture content of 19% and 47090 kJ / kg for a water-fuel emulsion with a water content of 32%. These results allow us to recommend the use of the resulting fuel for burning.

Example 4

In the table. 2 shows the characteristics of the initial fuel oil brand M-40 with a mass fraction of moisture of 1% and water-fuel emulsion with a mass fraction of moisture of 15%. Experiments conducted with an emulsion containing a large amount of water (15%) confirm that it has a higher calorific value (43372 kJ / kg) compared to non-watered fuel oil (41674 kJ / kg) containing a normalized amount of water.

The data presented allow us to recommend the resulting water-fuel emulsion and composite multicomponent fuel for use and combustion. In addition to improving the technological characteristics of the resulting fuel, one should take into account the increase in its volume due to the introduction of water.

Table 1

No. The name of indicators According to GOST 10585-99 Dry brand fuel oil M-100 M-100 brand fuel oil after cavitation treatment M-100 brand oil with manual introduction of water (22%) Water-fuel emulsion of the MM-100 brand Water-fuel-oil emulsion of the MM-100 brand one. Mass fraction of water,%, no more 1,0 0.5 traces 20.8 nineteen 32 2. Pour point, “C, not higher 25 27 27 26 29th 32 3. Calorific value (lower) in terms of dry fuel (not rejected), kJ / kg, not less than for sulfur dioxide for high sulfur 40530 39900 41343 42811 40440 58504 47090

- 5 013093

table 2

No. P/ P The name of indicators Norm for brands (GOST 10585-99) Original brand fuel oil M-40 Water-fuel emulsion of the MM-100 brand 40 one hundred one. Mass fraction of water,%, no more 1,0 1,0 1,0 16,0 2. Mass fraction of sulfur,%, no more for sulphurous sulfur sulfide 2.0 3,5 2.0 3,5 2,3 1.77 3. Pour point, ° C, not higher for heavy sulfur oil 10 25 25 42 24 32 4. Calorific value (lower) in terms of dry fuel (not rejected), kJ / kg, not less than for sulfur dioxide for high sulfur 40740 39900 40530 39900 41674 43372

CLAIM

Claims (1)

CLAIM A method of producing a water-fuel emulsion and a composite multicomponent fuel, including heating up to 120 ° C of the initial hydrocarbon feedstock with a water content of up to 50 wt.% And pressure treatment, characterized in that they carry out navigation processing until a finely dispersed water-fuel emulsion is formed containing water particles of size 0, 55.0 microns to ensure the subsequent rupture of water surrounding the hydrocarbon envelope and the secondary spray of fuel.