RU2815489C1 - Method for producing composite fuel - Google Patents

Abstract

FIELD: fuel suspensions.

SUBSTANCE: invention relates to methods for mixing solid fuel with liquid and can be used for preparing fuel suspensions and injecting them into the combustion chamber. A method for producing composite fuel is disclosed. Separately crushed coal with a particle size of 0.1–0.6 mm, water and waste transformer oil are simultaneously sprayed into the combustion chamber of the boiler. In this case, the opening angle of the nozzle of the device for supplying coal particles, the full-cone nozzle for spraying water and the pneumatic nozzle for spraying waste transformer oil is 60°, and the angle between the spray axes of the components is 10°. Crushed coal is sprayed under a pressure of 0.22 MPa, water is sprayed under a pressure of 0.2 MPa, waste transformer oil is sprayed under a pressure of 0.3 MPa. The following ratio of components is also observed, wt.%: crushed coal – 75; water – 5; waste transformer oil – 20.

EFFECT: production of composite fuel.

1 cl, 3 dwg

Description

The invention relates to methods for mixing solid fuel with liquid and can be used for preparing fuel suspensions and injecting them into the combustion chamber.

A known method for producing composite fuel [RU 2312889 C1, IPC C10L 1/32 (2006.01), B02C 13/00 (2006.01), B01F 3/12 (2006.01), publ. 12/20/2007], which consists of grinding at least one solid component, mixing the crushed particles with at least one liquid component and removing ballast inclusions from the resulting mixture. The grinding of the solid component is carried out by applying impact-shearing and/or compressive effects to its pieces, and before mixing the solid and liquid components, cavitation treatment of the liquid component is carried out.

However, when implementing this method, mechanical wear of fuel lines occurs due to friction of solid particles on metal when supplying finished fuel, mechanical wear of pump impellers and increased friction when fuel gets between moving parts of mechanisms.

A known method for producing liquid composite fuel [RU 2151959 C1, IPC F23K 5/10 (2000.01), publ. 06/27/2000], adopted as a prototype, which consists in obtaining at least one coal-water suspension obtained by mixing at least one type of crushed coal with water, while the specified suspension is mixed with at least one liquid fuel (oil, fuel oil, oil, diesel fuel , oil waste, various waste oil products) and with at least one colloidal solution, which is obtained by mixing at least one type of crushed peat with water, while mixing all components is carried out in any combination in relation to each other.

To store finished fuel obtained in this way and prevent its delamination, it is necessary to add plasticizers that negatively affect the environmental performance of flue gases generated during fuel combustion.

The technical result of the proposed invention is the development of a method for producing composite fuel.

The proposed method for producing composite fuel, as in the prototype, includes the use of crushed coal, water and liquid fuel,

According to the invention, separately crushed coal with a particle size of 0.1–0.6 mm, water and waste transformer oil are simultaneously sprayed into the combustion chamber of the boiler at the following component ratio, wt.%:

crushed coal with a particle size of 0.1–0.6 mm 75 water 5 waste transformer oil 20,

so that the opening angle of the nozzle of the coal particle supply device, the full-cone water spray nozzle and the pneumatic waste transformer oil spray nozzle is 60°, and the angle between the spray axes of the components is 10°, and the crushed coal is sprayed under a pressure of 0.22 MPa, water is sprayed under a pressure of 0.2 MPa, waste transformer oil is sprayed under a pressure of 0.3 MPa.

The production of composite fuel is ensured by a separate spray of its components supplied through independent pipelines and mixing of the sprayed flows directly in the combustion chamber of the boiler. Compared to the prototype, the proposed method eliminates the addition of chemical additives to the fuel composition that prevent its separation.

In fig. Figure 1 shows a diagram of an installation for implementing a method for producing composite fuel.

In fig. Figure 2 shows a diagram of the experimental setup used to control the process of spraying components.

In fig. Figure 3 shows the size distribution of droplets of composite fuel and its individual components.

To obtain composite fuel, we used the combustion chamber 1 of a boiler operating on liquid fuel, into the side wall of which a pneumatic nozzle 2 for supplying liquid fuel, a nozzle of a device for supplying coal particles 3, and a full-cone nozzle 4 for supplying water were inserted. The pneumatic nozzle 2 is connected by a pipeline 5 through a pump 6 to a reservoir filled, for example, with waste transformer oil. The nozzle of the device for supplying coal particles 3 is connected by a pipeline 7 through a pump for pumping bulk materials 8 to a tank filled with ground coal with a particle size of 0.1–0.6 mm. The full-cone nozzle 4 is connected to a container with water through a pipeline 9 through a pump 10.

The opening angle of the pneumatic nozzle 2, the full-cone nozzle 4 and the nozzle of the device for supplying coal particles 3 is 60°. The angle between the spray axes of the composite fuel components is 10° (Fig. 1).

The combustion chamber of the KVA-400 boiler can be used as combustion chamber 1. Pneumatic nozzle 2 for supplying liquid fuel – pneumatic nozzle T-20DT. As a device for supplying coal particles 3, a device for forming mixtures of pulverized fuel GPGK 26 can be used, providing coal consumption up to 4000 kg/h. Full cone nozzle for water supply 4 – full cone nozzle for spraying water Lechler 490.524 with a capacity of 50–500 kg/h. Pump 6 – pump for pumping oils and diesel fuel with kinematic viscosity up to 0.7⋅10 ³ m ² /s Adam Pumps E220/35. As pump 8 for pumping bulk materials, a pneumatic chamber pump UPTs-40 DZ (V) was used for pumping bulk materials. Pump 10 – water pump ONTs 25/50 K55A (2.2x1500) with a flow rate of 100–1000 kg/h.

Simultaneous supply of liquid and solid components into the combustion chamber 1 of the boiler is carried out. Transformer oil, fuel oil or other petroleum products can be used as liquid fuel.

Liquid fuel, for example, waste transformer oil, is supplied via pump 6 through pipeline 5 to pneumatic nozzle 2 and sprayed under a pressure of 0.3 MPa. Liquid fuel consumption is determined at the rate of 90–98 kg/h per 1 MW of thermal power. Ground coal with a particle size of 0.1–0.6 mm is sprayed through pipeline 7 using pump 8 through the nozzle of the device for supplying coal particles 3 under a pressure of 0.22 MPa. Using pump 10, water is supplied through pipeline 9 to full-cone nozzle 4 and sprayed under a pressure of 0.2 MPa.

Provide a mass fraction of coal of 75 wt.%, a mass fraction of water - 5 wt.%, a mass fraction of used transformer oil - 20 wt.%.

To determine the calorific value of the composite fuel, the following relationship was used:

Q _top = Q _comp1 ⋅α _comp1 + Q _comp2 ⋅α _comp2 + … + Q _compi ⋅α _compi ,

where _Qtop is the calorific value of the composite fuel;

Q _compi – calorific value of the i-th fuel component;

α _compi is the share of the i-th fuel component in the finished composite fuel.

Since the calorific value of waste transformer oil is 41 MJ/kg; the calorific value of coal is 28 MJ/kg; the specific heat of vaporization of water is 2.3 MJ/kg, then the calorific value of the composite fuel due to the mixing of the components during their spraying is:

Q_top= 41·0.2 + 28·0.75 - 2.3·0.05 = 29.1 MJ/kg.

The implementation of the method was tested using an installation (Fig. 2), which allows high-speed video recording of the spray of composite fuel components. Using pump 6, waste transformer oil was supplied through pipeline 5 to pneumatic nozzle 2 under a pressure of 0.3 MPa, providing an aerosol flow with droplet sizes of 0.2–1.5 mm into laboratory chamber 1. At the same time, ground coal with a particle size of 0.1–0.6 mm and water were sprayed into laboratory chamber 1 through pipeline 7 through the nozzle of a device for supplying coal particles 3 under a pressure of 0.22 MPa, which was supplied to a full-cone nozzle using pump 10 through pipeline 9 4 under a pressure of 0.2 MPa, ensuring the formation of an aerosol flow with droplet sizes of 0.025–0.95 mm. The process of spraying components was monitored using a viewing window 11 located in the wall of the laboratory chamber 1. To record the droplet interaction processes, a high-speed video camera 12 with a resolution of 1280×1024 pixels and a recording frequency from 3000 to 100,000 frames per second was used. The recording area was adjusted so that the process of droplet collision could be analyzed. High-speed video camera 12 was placed frontally to the study area. The recording area was additionally illuminated with a 13 General GOFL-30 diode spotlight. Based on the results of processing video frames, we obtained the distribution of fuel components by size (Fig. 3) for separate and joint feeding.

It was found that in the case of non-simultaneous spraying of composite fuel components through independent pipelines, the maximum number of water droplets, equal to 150–220 pcs., corresponds to a droplet size of 0.025–0.4 mm, the maximum number of coal particles, equal to 175–250 pcs., corresponds to particle size is 0.1–0.35 mm, and the maximum number of droplets of used transformer oil, equal to 30–50 pieces, corresponds to a droplet size of 0.3–1 mm.

With the simultaneous spraying of three components, composite fuel, supplied through separate pipelines, an increase in the number of droplets of composite fuel was found in the size range from 0.2 to 1.2 mm. In fig. 2 it can be seen that the sum of registered droplets and particles when fed separately exceeds the number of droplets of composite fuel. For example, the sum of drops of water, waste transformer oil and coal particles 0.5 mm in size is 209 pieces, and the number of drops of composite fuel components when fed separately is 114 pieces. This indicates the fusion of individual fuel components and the production of a composite fuel.

Claims (3)

A method for producing composite fuel, including the use of crushed coal, water and waste transformer oil, characterized in that separately crushed coal with a particle size of 0.1–0.6 mm, water and waste transformer oil are simultaneously sprayed into the combustion chamber of the boiler in the following ratio components, wt.%: crushed coal with a particle size of 0.1–0.6 mm 75 water 5 waste transformer oil 20, so that the opening angle of the nozzle of the coal particle supply device, the full-cone water spray nozzle and the pneumatic waste transformer oil spray nozzle is 60°, and the angle between the spray axes of the components is 10°, and the crushed coal is sprayed under a pressure of 0.22 MPa, water is sprayed under a pressure of 0.2 MPa, waste transformer oil is sprayed under a pressure of 0.3 MPa.