RU2736833C1 - Plant for processing of ash-slag wastes - Google Patents

Abstract

FIELD: power engineering.

SUBSTANCE: disclosed invention relates to power engineering, specifically to plant for processing ash from dumps of thermal power plants. Plant for processing ash-slag wastes comprises a device for separation of ash-slag pulp by fractions and size, device for classification of ash-slag particles and facility for dehydration of obtained products. Plant comprises a water tank, connected by pipeline with device for separation of ash-and-slag pulp by fractions and size, which is a vibration screen, for sequential passage through ash-and-slag pulp screens and separation of slag crushed stone, slag sand. Lower screen is connected to vessel equipped with device for mixing, which outlet is connected to sand pump for pumping of pulp via pipeline to input of first hydraulic cyclone of device for classification of ash-slag particles, consisting of hydrocyclones system and vibrotray. First hydrocyclone provides separation of pulp into ash component and sand fraction, its lower conical part is connected by pipeline for removal of pulp sand fraction from it, consisting mainly of microspheres and coal underburning particles, and their supply to the second hydrocyclone for cleaning and additional separation of ash component. Upper parts of the first and the second hydro cyclones are connected by pipelines to the inlet of the third hydrocyclone providing separation of the ash component from water. Outlet of the third hydrocyclone is connected to a filter bag arranged in the product dehydration facility and made in the form of a centrifuge. Output of the second hydrocyclone is connected to a vibratory chute, providing separation of sand fraction into two layers - upper layer, consisting of coal underburning, and lower, consisting of microspheres entering into filter bags, located in centrifuge for squeezing produced products.

EFFECT: higher efficiency of recycling ash-slag wastes, as well as reduction of environmental pollution.

1 cl, 1 dwg

Description

The invention relates to the field of energy, specifically to a plant for processing ash from dumps of thermal power plants.

The integrated use of the main components of ash and slag waste (carbon, magnetic minerals, aluminosilicates) located in wet ash dumps of TPPs is becoming a priority for obtaining valuable ash processing products for many industries and the national economy.

Known installation for the integrated processing of ash dumps of thermal power plants (patent RU No. 2614003, IPC В03В 9/04, publ. 2016), containing means for separating ash pulp into coarse and fine fractions, as well as flotation and magnetic separation to obtain target products ... The ash pulp separator is made in the form of a screen, the output of which is connected to the inlet of the first section for the production of concrete mixtures in coarse fraction. The screen outlet for fines is connected to the inlet of the first flotation machine for basic flotation, the first outlet of which is connected through the second cleaning flotation machine, filtration and drying units to the inlet of the second section for storing coal concentrate. The second outlet of the first flotation machine is connected to the first inlet of the magnetic separation unit, the first outlet of which is connected through a drainage silo to the inlet of the third section for storing magnetite concentrate. The second outlet of the magnetic separation unit is connected through the thickener and drying units with the inlet of the third section for storing aluminosilicate concentrate. The outlet of the drainage silo through water is connected to the second inlet of the magnetic separation unit. In the main flotation, a collector-kerosene and pine oil are used as a blowing agent. Purification flotation is carried out using recycled water.

The disadvantages of the installation are the use of chemical reagents, which leads to an increase in the cost of the products obtained on it with low efficiency and duration of the processing period for ash dumps.

There is a known system for processing fly ash from thermal power plants to obtain from it aluminosilicate, carbon and magnetic fractions, including iron-containing microspheres (RU patent for utility model 142957, 07/10/2014), including means for separating it into light and heavy fractions in a separating medium, means for separating ash into light and heavy fractions comprise a first device for electrodynamic separation of ash in a descending separating medium into magnetic and non-magnetic fractions, the first output of which in terms of the magnetic fraction is connected through a series-connected second device for scrubbing the residual non-magnetic fraction, the third device for hydraulic classification of magnetic fraction in an ascending separating medium, a fourth device for filtering the magnetic fraction on a belt vacuum filter and a fifth device for drying it in a drum dryer with an inlet of the sixth device for dry classification of the magnetic fraction on sieves according to the size range, the second in The outlet of the first device for the non-magnetic fraction is connected to the inlet of the seventh device for flotation separation of the non-magnetic fraction into aluminosilicate and carbon-containing products. In addition, the outlets of the sixth device for dry classification of the magnetic fraction on sieves can be connected for each size row to the inlets of magnetic separators made in the form of vertical dividing columns equipped with magnetic traps for classifying magnetic microspheres by diameter.

The combined processing method includes the following stages:

- separation of ash into light and heavy fractions in a separating medium (magnetic and non-magnetic fractions) (electrodynamic separation);

- scrubbing the residual magnetic fraction and hydraulic classification of the magnetic fraction;

- filtration of the magnetic (heavy) fraction on a vacuum filter;

- drying it in a drum dryer;

- classification of the magnetic fraction by size;

- flotation separation of non-magnetic (light) fraction into aluminosilicate and carbon-containing products.

The disadvantages of the known technical solution include incomplete separation of ash components into fractions in one processing cycle and the complexity or impossibility of complete complex processing of ash from waste dumps of thermal power plants.

Known production line for the separation of valuable components from ash and slag waste (patent RU 2393020 C1, 06/27/2010), which includes a series-connected hopper, devices for magnetic separation in strong and weak fields, an electrostatic separator, leaching devices. The line is additionally equipped with series-connected flotation machines installed after the receiving hopper for the separation of xenospheres and classifiers for separating material into size classes for its further processing in various streams. The line is also equipped with additional magnetic and electrostatic separators, leaching devices, filters and dryers installed in series after the classifier.

The disadvantages of the known line are the content in it of a large number of different technological equipment, the use of chemical reagents, which leads to an increase in the cost of the products obtained on it with low efficiency and the duration of the processing period of ash dumps until they are completely destroyed in order to free lands from them.

There is a known technological line described in the method of complex processing of ash and slag waste from thermal power plants (patent RU 2588521, publ. 27.06.2016), which includes a system for transporting ash and slag waste, a waste preparation unit with the removal of underburning and a series of technological conversions aimed at selective extraction of iron-containing and aluminosilicate concentrates, as well as precious metals. Slagged ash and slag waste with a particle size of no more than 0.5 mm is sent to magnetic separation. Removal of underburning is carried out in the form of a fraction of +0.5 mm when classifying on a screen. The separation of underburning in the form of a +0.5 mm fraction ensures the purity of underburning from microspheres. Microspheres with pulp are fed to hydrocyclones and are removed from further processing with discharge.

The disadvantages of the known line is that the separation of underburning from ash and slag materials is carried out according to the principle of removing the coarse fraction from the mixture containing its highest concentration. This method does not allow to extract coal underburning from the entire volume of ash and slag materials to a content of 1% by weight. This technology does not provide for the processing and disposal of the entire volume of ash and slag materials.

Known technological line for processing ash and slag waste from thermal power plants (patent RU 2363885, IPC В03В 9/04, publ. 2009), which contains a feeder feeder for ash and slag waste and a meter for the consistency of the liquefied ash and slag mixture. The processing line may also further comprise a device for grinding large particles of the liquefied ash and slag mixture.

The disadvantages of the known line are the impossibility of obtaining ash and slag materials after activation in water of a homogeneous composition and repeated physical characteristics of the materials of the released batches of products, since this is a difficult to predict process. Also, this process requires high speeds of the slurry in the mixing zone and the pressure of the medium in the pipelines, and as a result, energy-intensive equipment is needed to implement the technology.

The closest is the installation described in the method of material separation (US 6666335, IPC В03В 9/04, publ. 2003,), which includes feeding material onto a coarse primary screen, as a result of which a very coarse material is separated from the first residual material; shredding very coarse material and returning the shredded material to the primary sieve; feeding material from the primary sieve to the secondary sieve to separate the first size material from the second residual material; removing ferrous materials from the second material residue; Feeding iron-free material into a hydraulic classifier that classifies materials into coarse, medium and fine; combining the coarse materials from the hydraulic classifier with the first size material and dewatering the combination of materials, resulting in a blocky sand product; feeding fines from a hydraulic classifier to a stationary screen, resulting in a fines ash product; feeding medium-sized material from a hydraulic classifier into spirals to separate medium-sized material into high, medium and low specific gravity; passing a low specific gravity material through a sizing sleeve; feeding medium specific gravity material from the spiral and feeding coarse medium specific gravity material from the sizing sleeve to the dewatering screen; storage of materials from the screen for dewatering in the form of medium-sized concrete or sand.

The disadvantages of the prototype are that it is not provided for the allocation of underburned coal from the ash and slag mixture. The products resulting from the classification are intended as fillers in concrete or building sand. Coal underburning is a softening component in concrete compositions due to the hydrophobicity and low strength of particles.

In addition, the coarse fractions of the ash and slag mixture are crushed to the size of sand and re-classified, which complicates the process. The separation of the fine ash product (ash component) is carried out in a stationary screen. To carry out this process, first, the ash and slag mixture must be separated into water and solid particles, then dried to 10% of the mass. and less in order for the material to acquire the property of flowability. Otherwise, the screening process is ineffective, since the ash and slag mixture in a wet state is prone to sticking (pelletizing). Also, the process of screening fine materials is accompanied by high dusting, which leads to environmental pollution.

The task is to develop an installation that does not use chemical reagents and its use does not lead to the formation, in addition to the existing, recycled process water circulating in the hydrotransportation system of ash and slag waste, waste water and toxic emissions into the atmosphere.

The technical result of the claimed invention is to provide the possibility of efficient disposal of ash and slag waste due to the removal of coal underburning, expanding the range of fractionation of ash and slag waste in terms of size, specific gravity and particle shape, as well as reducing environmental pollution.

The technical result is achieved in an installation for processing ash and slag waste containing a device for separating ash and slag slurry by fractions and size, a device for classifying ash and slag particles and a means for dewatering the products obtained, and the installation contains a container with water connected by a pipeline with a device for separating ash and slag slurry by fractions and size, which is a vibrating sieve, for sequential passage of ash and slag slurry through the sieve and separating slag crushed stone, slag sand from it, and the lower sieve is connected to a tank equipped with a mixing device, the outlet of which is connected to a sand pump for pumping the slurry through a pipeline to the inlet of the first hydrocyclone of the classification device ash and slag particles, consisting of a system of hydrocyclones and a vibrating tray, while the first hydrocyclone separates the pulp into an ash component and a sand fraction, and its lower conical part is connected by a pipeline for withdrawing from it the sand fraction of the pulp, consisting mainly of microspheres and particles of underburned coal, and feeding them into the second hydrocyclone for cleaning and additional separation of the ash component, and the upper part of the first and second hydrocyclones are connected by pipelines to the inlet of the third hydrocyclone, which ensures the separation of the ash component from water , while the outlet of the third hydrocyclone is connected to a filter bag located in the means for dewatering the obtained products, made in the form of a centrifuge, and the outlet of the second hydrocyclone is connected to a vibrating tray, providing separation of the sand fraction into two layers, the upper layer consisting of coal underburning, and the lower consisting of microspheres entering filter bags located in a centrifuge to squeeze the obtained products.

The vibrating sieve consists of three sieves with woven square cells: 20 mm; 5 mm; 0.5 mm.

The plant is designed to separate ash and slag pulp into components according to size, specific weight and shape factor.

The advantage of the proposed installation in comparison with the prototype is that the separation of the small ash product is carried out in hydrocyclones in the form of pulp (suspension). Thus, there is no dust formation, which does not lead to environmental pollution. This method is highly productive and energy efficient, in contrast to the process of screening fine materials in the prototype.

In addition, in the declared installation, the products are manufactured in accordance with the requirements of regulatory and technical documents.

As a result of separation at the plant, the following are obtained: main products: slag sand;

aluminosilicate microsphere concentrate

coal underburned concentrate.

Additional products:

crushed slag;

ash component.

The installation diagram is shown in Fig.

The installation for the processing of ash and slag waste contains a container with water 1, for washing the vibrating sieve 2 in case of feeding ash and slag waste (pulp) in dry form or for diluting highly concentrated ash and slag pulp over 40% by weight, connected by pipeline 19 with a device for separating ash and slag pulp into fractions and the size, which is a vibrating sieve 2 for sequential passage through the sieve of the pulp and the separation of slag crushed stone, slag sand from it and their collection in the respective collectors 15, 16, 17, and the lower sieve is connected to a container 3, equipped with a device for mixing, the outlet of which is connected with a sand pump 4 for pumping the pulp through the pipeline 21 to the inlet of the first hydrocyclone 7, a device for classifying ash and slag particles, consisting of a system of hydrocyclones 7, 8, 9 and a vibrating tray 10, while the first hydrocyclone separates the pulp into an ash component and a sand fraction, and its the lower conical part is connected by a 24 d pipeline To remove from it the sand fraction of the pulp, consisting mainly of microspheres and particles of coal underburning and supply them to the second hydrocyclone 9, which provides cleaning and additional separation of the ash component, and the upper part of the first 7 and second 9 hydrocyclones are connected by pipelines 23 and 25 with the inlet of the third hydrocyclone 8, providing the separation of the ash component from water, while the outlet of the third hydrocyclone 8 is connected to a filter bag 14 located in a means for dewatering the obtained products, made in the form of a centrifuge 11, and the outlet of the second hydrocyclone 9 is connected to a vibrating tray 10, providing the separation of the concentrate into two layer, the upper layer, consisting of underburned coal, and the bottom, consisting of microspheres, entering the filter bags 12, 13, located in the centrifuge 11 for pressing the obtained products.

Vibrating sieve 2 consists of three sieves with square braided cells: 20; five; 0.5 mm.

The installation works as follows:

Separation of components is based on physical principles and distinctive (contrasting) properties of ash and slag materials components, namely: size; specific gravity; form factor.

Ash and slag slurry is fed to the plant through pipeline 18. From tank 1 with water through pipeline 19, water is supplied for washing the vibrating sieve in case of feeding ash and slag slurry in dry form or for diluting highly concentrated slurry over 40% by weight. The pulp is fed by gravity to a vibrating sieve 2, on which three sieves with braided square cells are installed: 20; five; 0.5 mm. Successively passing through the sieves from the pulp, slag crushed stone, slag sand are separated and discharged through the pipes to the corresponding collectors 15, 16, 17. The fraction of 0.5 mm passing through the lower sieve refers to the ash fraction of the pulp. To prevent delamination and sedimentation of the ash fraction of the pulp after the vibrating sieve, it is drained by gravity through the pipeline 20 into the tank 3, equipped with a mixing device, designed for preparing the pulp. In tank 3, the ash fraction is intensively mixed with a mixer until homogeneous. From the tank 3, the homogenized slurry is fed through the pipeline 21 to the inlet of the sand pump 4. The pump 4 pumps the slurry through the pipeline 22 to the inlet of the hydrocyclone 7. In the hydrocyclone 7, in the field of centrifugal forces, the pulp is separated into an ash component and a sand fraction. At the appropriate pressure at the inlet to the hydrocyclone 7, classification occurs: namely, in the conical part of the sand fraction (heavy and coarse fraction of the pulp), consisting mainly of microspheres and particles of underburned coal, which is discharged through the sand hole into pipeline 24, and the ash component (light part of the pulp), consisting mainly of dusty and debris particles, with the main part of the water exits through the drain of the hydrocyclone 7 and enters the pipeline 23.

The heavy and coarse fraction of the pulp through the pipeline 24 enters the inlet of the hydrocyclone 9, in which the cleaning takes place and the ash component is additionally separated, which from the discharge of the hydrocyclone 9 through the pipeline 25 enters the inlet of the hydrocyclone 8, where the pulp with the main volume of the ash component - the drain from hydrocyclone 7. In hydrocyclone 8 the ash component of the pulp is concentrated. The concentrate is discharged through the pipeline 27 into the filter bag 14 located in the rotor of the centrifuge 11

The water clarified from the ash component from the discharge of the hydrocyclone 8 through the pipeline 26 is supplied, if necessary, to the irrigation of the upper sieve of the vibrating sieve 2 or to the discharge.

The heavy and coarse fraction of pulp, which has undergone cleaning in hydrocyclone 9, in the form of a concentrate, consisting mainly of underburned coal and ash microspheres, from the sand hole of hydrocyclone 9 through pipeline 28 enters the vibrating channel 10. Under the action of vibration, the concentrate layer is separated into two products differing in density ... Coal underburning is concentrated in the upper layer, and a sinking microsphere in the lower layer. Filter bags 12, 13, 14 are laid out on the centrifuge drum 11 evenly and the resulting products are squeezed out. Dehydrated products after stopping the centrifuge from filter bags 12, 13, 14 are transferred to a suitable container.

The installation also includes a water tank 6 and the ability to connect to a pressure pipeline of service water. The presence of clean industrial water is necessary for flushing the gland seal of the sand pump 4, flushing equipment and pipelines after work, as well as ensuring the dilution of the slurry in case of technological need. Water is supplied by pump 5.

A pilot plant works according to the invention.

Products are manufactured in accordance with the requirements of regulatory and technical documents:

1. Ordinary crushed stone from slags of thermal power plants (fractions 40 - 20 mm, 20-5 mm)

GOST 26644-85

2. Sand from slags of thermal power plants (fraction 5 - 0.5 mm)

GOST 26644-85

3. Concentrate of underburned coal (grades by coal concentration - 25, 50, 75% of the mass.)

TU 0763-001-0206-9303-2016

4. Microspheres, aluminosilicate

TU 5712-089-00884306-2016

5. Ash component

GOST25592-91

Thus, the proposed installation for processing ash and slag waste provides the possibility of effective disposal of ash and slag waste, due to the removal of coal underburn, the range of fractionation of ash and slag waste by size, specific gravity and particle shape is expanded, and environmental pollution is reduced.

Claims (2)

1. Installation for processing ash and slag waste, containing a device for separating ash and slag slurry by fractions and size, a device for classifying ash and slag particles and a means for dewatering the resulting products, characterized in that the installation contains a container with water connected by a pipeline with a device for separating ash and slag slurry into fractions and the size, which is a vibrating sieve, for sequential passage of ash and slag slurry through the sieve and separating crushed stone, slag sand from it, and the lower sieve is connected to a tank equipped with a mixing device, the outlet of which is connected to a sand pump for pumping the slurry through a pipeline to the inlet of the first hydrocyclone a device for the classification of ash and slag particles, consisting of a system of hydrocyclones and a vibrating tray, while the first hydrocyclone separates the pulp into an ash component and a sand fraction, and its lower conical part is connected by a pipeline for withdrawing oil from it of the slurry fraction, consisting mainly of microspheres and particles of underburned coal, and feeding them into the second hydrocyclone for cleaning and additional separation of the ash component, and the upper parts of the first and second hydrocyclones are connected by pipelines to the inlet of the third hydrocyclone, which ensures the separation of the ash component from water, while the outlet of the third hydrocyclone is connected to a filter bag located in the means for dewatering the obtained products, made in the form of a centrifuge, and the outlet of the second hydrocyclone is connected to a vibrating tray, which ensures the separation of the sand fraction into two layers, the upper layer consisting of coal underburning, and the lower one consisting of microspheres entering filter bags located in a centrifuge to squeeze the obtained products. 2. Installation according to claim 1, characterized in that the vibrating sieve consists of three sieves with braided square cells: 20 mm; 5 mm; 0.5 mm.

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