Press for briquettes from coal dust. Coal briquette: what is it, what raw materials are used

Ever-increasing energy and fuel prices are forcing consumers to be more selective in their choices or find alternatives to save money while maximizing their return on investment. In our time, this is not easy to do, because there are plenty of offers on the market, in addition, new technological types of calorific materials often appear, so you have to study existing options so as not to throw money away.

Coal-wood briquettes: varieties of raw materials

Relatively low price, ease of manufacture, availability of purchase and efficiency of fuel briquettes has led to an increasing popularity among consumers and their widespread distribution. Meanwhile, there are varieties of this type of fuel according to the raw materials used, as well as the shape of the final product.

Coal briquettes for heating are produced from different types coal such as:

• brown (the most common and cheapest option);
• wood (more complex manufacturing technology, involving the use of additional equipment);
• anthracite (the most expensive, but also the most efficient raw material: the best heat transfer rates).

The production of briquetted fuel does not require high quality raw materials. Coal dust and fines are quite suitable for this purpose, as well as waste that does not bake well, falls through the grate and is not suitable for direct use in furnaces or coke production.

Adhesives

Various components can be used as a binder, which affect the quality and characteristics of the final product. These are substances such as:

• coal tar;
• clay;
• soda;
• syrup;
• resin;
• dextrin;
• lime;
• protein and many others.

The choice of a binding component directly depends on the type of the main raw material and its quality. Also, depending on the use of a particular component, the technology for the production of briquettes and its labor intensity will change.

What are

Coal briquette is a solid fuel product made in the form of bars of various configurations and sizes, which are pressed under high pressure and temperature. To bond the particles of raw materials and the strength of products, cementing components are used, which can be organic and inorganic.

The efficiency of this energy carrier lies in its heat transfer parameters and burning duration, which are higher than those of conventional hard coal. The shape and density of the briquettes are also important for efficiency, as they help the fuel to maintain even, predictable burn-out and a constant temperature throughout the entire combustion process. The waste in the form of ash remaining after attenuation is only 3%, for traditional coal this figure is 10 times higher, while the briquettes do not fall apart in the furnace until they burn out completely.

Where to use and where not to use

It is mainly used for heating needs in everyday life, but more recently it has been used more often in metallurgical and chemical enterprises, as well as in power plants and boiler houses. In general, briquettes can be used at any enterprise or in a private house where equipment is installed that runs on solid fuels - coal, wood, etc.

But you should be aware that in no case should you use a coal briquette to make a fire in barbecues, grills and other ovens for cooking, on which there is direct contact of smoke with food. Such equipment is simply not designed for the temperature produced by this fuel, and it will fail, and the released caustic and harmful substances contained in coal will make food unfit for consumption.

Production in industrial volumes

Since the manufacturing technology is somewhat different depending on the type of binder, we can consider the production of coal briquettes based on the most commonly used component - coal tar (coal tar).

First, the raw material is washed from weed impurities, and then crushed and dried to the required parameters. For this purpose, it is poured through the receiving hopper into the crusher, and then, through the auger, it enters the dryer. Dried coal fines are sorted into fractions: coals ranging in size from 0 to 6 cm enter the mixer, and large ones go back to the crusher. After calibration, a binder is added to the prepared basic raw material in the mixer.

When the required components are loaded, they are mixed into a homogeneous mass, which is distributed over the cells of the molds, where, using hot steam and high pressure, the resulting mixture is converted into a coal briquette. The resulting products are transferred to the cooling hopper for 8 hours. Screening of defective forms and subsequent packing in 25 kg bags complete the production process.

Do-it-yourself coal briquettes

For these purposes, you can use a hand press or a homemade screw extruder. You can also, in the absence of equipment, do it manually. Unlike the factory manufacturing process, at home, instead of drying coal fines, on the contrary, they mix it with water. No binder needs to be added. The main thing is to observe two conditions:

• fraction of coal - no more than 6 cm and the smaller, the better;
• the resulting mass must be plastic and thick so that it can be molded by hand or briquetted in a mold using a hand press.

After the briquetting process, the products should be dried well. It should be noted that the coal briquette obtained by manual pressing is unsuitable for transportation, since it is more fragile than the factory one. Also, the manual method has very low productivity: it will take a lot of effort and time to prepare fuel for the whole season.

The use of an extruder speeds up the briquetting process, and the quality of the products is much higher than with manual way manufacturing. Here you just need to pour raw materials into the bunker and get finished goods high quality, suitable for transportation. However, the cost of the unit itself and its components (electric motor, gearbox, etc.) are high and not everyone can afford it.

Condition Requirements environment at the place of installation

Installation height	up to 1000 m
Design for operation	indoors
Temperature
On mechanical equipment	min. 5 °C
On control cabinets	min. 5 °С, max 40 °С
Air humidity	Max. 75%
Electrician
Execution	DIN/IEC
Low voltage
Nom. voltage	400 V, ± 5%
Network frequency	50 Hz, ± 5%
Control voltage
Rated voltage	24V DC current/110V
Network frequency	50 Hz
Raw material data:
Feed material:	coke breeze
Bulk density	0.9 g/cm³
Particle size Temperature	up to 6 mm Environment
Max. permissible water content	4%
Binder	Bentonite ok. 5% Starch ok. 2%

Received product:

Description of equipment. Specifications

Frame

The press frame is a welded structure, made in such a way that the pressing forces are damped inside the frame and are not transferred to the foundation.

To facilitate the replacement of rolls, the end cheeks of the frame are connected to the upper/lower chords by pivot bolts. When the upper bolt is loosened, they (cheeks) can be tilted to a horizontal position, they serve to remove the rolls.

rolls

Rolls with axial trunnions are made of forged steel.

Press forms

Molds made of wear-resistant material are used, the molds are mounted on the roll body.

Setting the roll gap

The distance and clearance of the rolls is adjusted through intermediate pieces inserted between the rolling bearing housing.

If desired, the gap can be controlled by an inductive displacement sensor, observing the parameters on the control panel.

Bearing filled with grease

The rolls are mounted on ball bearings with bushings, the bodies of which are sealed with labyrinth seals and rings. The bearings are filled with grease during installation.

Hydraulic pressing system

The roll is supported by the bearing housing on the hydraulic pressing device, which is necessary for the uniformity of the pressing force, as well as for uniform distribution of the load on the frame and protects the press from overload.

Includes:

• Pressurized cylinder
• Nitrogen accumulator
• pressure gauge
• Remote pressure sensor
• Safety valves
• Oil tank with pump
• Drive motor 3 kW
• fittings
• Fill level controller
• Thermometer

The hydraulic system maintains the set pressure and ensures a constant pressing force.

Roll cover

To prevent the appearance of dust, the rolls are surrounded by a casing, which is sealed in the rotating parts with labyrinth seals. The casing has a flange at the end for connection with the tray. Holes are provided for connection to the dust extractor.

Material supply

The gravity feed device is mounted on the press frame and consists of:

• Floor slab with feed funnel
• Hopper

main drive

The drive consists of:

• Reducer with two tapping pins
• Overload clutch between motor and gearbox
• Two double gear couplings between gearbox and press roll

KIP and A

Instrumentation devices are connected in terminal boxes (transfer point) by metric cable glands on terminal boards. The cable to the press is laid in flexible hoses. Cable designation according to DIN/IEC.

The following devices are installed on the press:

• Proximity sensor with speed change relay on the main drive motor, 24VDC signal current
• pressure sensor on the hydraulic pressing system for measuring oil pressure passive signal 4 - 20 mA
• Solenoid oil pressure valve
• Manometer for monitoring the pressure of the hydraulic system

Field control panel (wall mounting)

To service the roller press during the production process, a control panel is installed next to the press.

The console is equipped with the following devices:

Painting- standard

Miscellaneous

1 set of tools for mounting roll supports

1 set for checking and filling the hydraulic system

Material performance

All parts in contact with the product are made of structural steel, unless otherwise specified.

The scope of supply includes the equipment listed above, unless otherwise noted. Also includes drawings, the necessary documentation for start-up, operation, a list of spare parts.

Optional

• Organization of the installation site, including cleaning and leveling, topographic surveys, soil analysis, infrastructure organization
• Permits Required by State and Government Authorities
• Construction and supply of buildings, as well as internal construction of platforms for operation and maintenance
• Manufacture and supply of mechanical connections to the Customer's equipment in the plant
• Dusting of pipelines
• Insulation and measures for its installation
• Consumables such as oils and greases
• Spare parts and wearing parts
• Transportation and storage of raw materials
• Materials, auxiliary devices (tools, cranes) and personnel for installation and commissioning
• Programming device
• Electrical equipment between low voltage distributors, control panels and electrical units, instrumentation, safety devices (fire protection, etc.)
• Departmental acceptance and launch
• Transportation, storage and packaging of other finished products
• Other services and equipment not specified in the offer

Drying plant to ensure the necessary moisture content of raw materials before feeding them to the briquetting plant

Coal briquetting technologies are designed to produce marketable products from coal dust, screenings, substandard and low-quality coal. Black or brown coals, as well as coke, can be used as raw materials.

Coal briquetting is a very old technology that has evolved with the use of double-roller roller presses to increase productivity and improve the economic viability of this business.

SAHUT-CONREUR was one of the companies that started the production of double roller presses at the beginning of the 20th century. We are located in northern France and since the beginning of the 20th century, we have installed more than 1000 briquetting plants in different parts of the world, more than 350 of them for coal briquetting.

The technology of coal briquetting on roller presses was developed for the production of briquettes from coal fines coming after coal sieves and washing. The briquettes are intended for use as fuel for private or industrial boilers in the same way as standard coal, and are also packaged for retail and in this form can be exported.

In most cases, the process of coal briquetting occurs with the addition of a binder (coal pitch, petroleum bitumen, tar, molasses and lime, lignosulfonate, starch, polymers…). In some cases, briquetting is also possible without a binder.

ADVANTAGES OF BRIQUETTED COAL

Technical solution:

• Obtaining a product of the same size, volume, shape and weight.
• Elimination of the problem of dust formation and marriage during transportation.
• Specified hardness and strength of the briquette.
• Utilization of waste into marketable products

Consumer and Marketing Benefits:

• Higher energy value
• Longer burning
• Ash in powder form
• Less CO2 and sulfur emissions
• Easier packing, transportation, warehousing
• Ready for automatic feeding into the firebox
• Possibility of packaging for the consumer market
• Export deliveries

COAL BRIQUETTING WITHOUT BINDER

The coal briquetting plant without binder consists of the following components:

The capacity of a coal briquetting plant without a binder can range from a few tons per hour to about 25 t/h.

COAL BRIQUETTING WITH BINDING

The plant for briquetting coal with a binder consists of the following sections:

• area for sorting and grinding coal, if the dimensions of the coal are too large
• drying section if the moisture content of the coal is too high
• binder addition section
• briquetting station on a two-roller press
• (optional) post-processing area (cooling, ripening and drying depending on the binder used)

The capacity of the plant for the production of briquettes from coal with a binder can be from several tons per hour to 100 t/h for large presses.

Possible binders

• coal pitch
• petroleum bitumen
• resin
• molasses and lime
• lignosulfonate
• starch
• polymers, etc.

The specific binder for coal briquettes is determined by regional availability and end product requirements. The optimal proportions of the binder and the parameters of the finished briquette are determined when testing coal in France at the Sahut-Conreur pilot plant.

Testing of raw material and binder for coal briquettes

Coal in each particular deposit has individual chemical and physical characteristics, and different binders may be available in each region.

To accurately determine the required composition and characteristics of the equipment, it is necessary to conduct preliminary testing of the customer's material at the manufacturing plant of Sahut Conreur SA in France. To conduct tests, the customer needs to send coal to France for testing.

As a result of the tests it will be possible to:

• determine the required composition and characteristics of the equipment
• determine the type and proportions of the binder
• get a finished briquette and determine its characteristics
• calculate exact economic indicators production

Also, only during testing it is possible to determine whether coal is suitable for briquetting without a binder and what in this case will be the technical and economic indicators of production, as well as the quality characteristics of the briquette.

COMPARISON OF OPTIONS FOR COAL BRIKETING WITH AND WITHOUT BINDER

Briquetting of coal using a binder:

• + Suitable for any coal or lignite
• + High productivity (up to 100 t/h)
• +
• + Possibility to receive moisture-proof briquettes
• + Low cost Supplies
• - More expensive and more complex equipment, a binder is required

Briquetting coal without a binder:

• - Applicable only for certain coals
• - Drying required
• - Limited capacity (up to 25 t/h)
• - High specific energy consumption
• - High cost of consumables
• + No binder, simpler and cheaper equipment

The technology of coal briquetting without binding additives seems more attractive at first glance, but at the same time, energy costs increase significantly, productivity and quality of the briquette decreases.

After testing, it usually becomes clear that briquetting using a binder is more economically justified, even taking into account the costs of purchasing, shipping and storing these materials.

Stages of the technological process of briquetting coal and coke

Grinding of coal in a hammer mill

Grinding of coal is necessary to obtain the required homogeneous fraction, therefore, before or after drying, coal is passed through a hammer mill.

Drying coal in a dryer

Drying is necessary to reduce the moisture content of the coal before the introduction of the binder. The degree of drying depends on the used binder and technology. Final product has a moisture content of 5-10%.

Pressing crushed coal and coal dust

Pressing of coal dust and crushed coal fraction is carried out on two-roller presses that meet the requirements of the industry:

• High performance
• Low specific energy consumption
• High reliability

Our partner is the world leader in the production of this equipment, the French company "Sahut Conreur".

Post-processing (ripening) of coal briquettes

Depending on the type of coal and binder in the technology, it may be necessary to cool and hold the finished briquette in a special way for some time in special bins, during which the briquette acquires strength.

The holding time is individual and is determined at the testing stage.

If you are interested in the technology of production of coal briquettes, we will be happy to answer

Charcoal is a solid porous high-carbon product obtained from wood by heating without air access (or with little air access) in retorts, ovens or heaps. Many companies that produce charcoal are faced with the problem of a large waste of charcoal in the form of dust and small pieces (screenings) due to the excessive fragility of the material.

Our company has found a REVOLUTIONARY solution to this problem and introduced a NEW product to the market - equipment for the production of charcoal briquettes in the form of an extruder-briquetting press with a thermoactive output die, PRODUCTIVITY from 500 to 1500 kg / h !!! Special technology production allows to achieve high quality and environmental cleanliness finished products. Charcoal briquettes are produced by pressing a mixture of screenings, crushed into dust, with a binder on an extruder press, thanks to high pressure in a conical compression chamber (about 2000 kg / cm2) and heat treatment at the exit. This allows you to produce high-quality briquettes of various shapes:
1. Round type "Nestro", with a diameter of 40 to 60 mm - at the request of the customer.
2. Octagonal or square type Pini-Key "from 50X50 to 63X63 with a hole in the center.

Charcoal briquette (briquetted coal) is an environmentally friendly product that is used for cooking grills, barbecues, etc., and it is also an ideal fuel for barbecues, stoves, fireplaces, all types of fireboxes, for heating tents, greenhouses. Charcoal briquette is an indispensable tool for creating comfort in field conditions, at a picnic, fishing, hunting.

Duration of burning of coal briquettes makes 4-5 hours, unlike usual charcoal which burns 1-2 hours.

The constancy of temperature during combustion for 4-5 hours favorably distinguishes briquettes from ordinary charcoal.

Possibility to reuse charcoal briquettes - after use they can be filled with water, under the influence of sunlight and wind the briquettes dry out and are ready for use again.

Charcoal briquettes burn without smoke, do not sparkle, practically do not emit any volatile substances during combustion, which eliminates the possibility of spreading an unpleasant odor.

Content

Affordable price compared to other types of energy carriers, no problems with the purchase, good heat transfer are the main reasons why many users prefer to use coal briquettes for heating. The price of more familiar energy carriers is constantly increasing, which forces us to look for alternative sources of heat. Coal dust is an affordable type of fuel, but its use in its pure form is unprofitable: half of the raw material falls into the ash through the bars of the grate, and the other half is sintered, which leads to clogging of the firebox.

coal briquettes

One of the options for using coal dust, which allows you to get the maximum heat out of it, is to pour the fraction on firewood, with which the boiler is pre-heated. But this is very troublesome, since it often needs to be poured in small portions. An embankment of a large amount of fine fraction will lead to the fact that it will still spill into the ash pan, turning into waste. And the part that still remains on the wood will fill the gaps between them, blocking the air circulation and provoking the attenuation of the firebox.

The way out is the production of briquettes from dust with the addition of excipients by pressing. The fine fraction processed in this way burns perfectly with high heat transfer.

More about briquetting technology

At the beginning of the last century, the Russian researcher A.P. Veshnyakov suggested pressing the fine fraction into elements of a certain shape and size, which, in terms of heat transfer, were not inferior to coal itself. The idea has found wide application both in everyday life and in industry.

Briquettes of coal on a screening belt

Today, pressed coal is classified depending on the material, environmental friendliness, security, shape and type of packaging. But the two main types are:

• For production with the addition of binding components.
• For home use without additives.

It is important to know that production briquettes should not be used in everyday life. When they are burned, a large amount of toxic substances are released, for the removal of which, under production conditions, is responsible special equipment. Previously, in the manufacture of household briquettes, additives in the form of molasses or starch were used. But this technology is a thing of the past.

industrial production

Distinctive features of dust and fine coal fraction: low specific calorific value and density. But these materials are considered as cheap raw materials that allow organizing the production of coal briquettes. The products will have good density and heat dissipation at a low cost.

For the manufacture of briquettes in the factory, a special technological line is used, consisting of a crusher, dryer, press. The movement of semi-finished products between machines is provided by a belt conveyor.

Pressed coal without additives is produced in several stages:

• Grinding of raw materials to a particle size of 6 mm and smaller.
• Drying the mixture to 15% moisture using steam and gas dryers.
• Further, the dust is cooled and fed to a stamp-type press, which acts on the mixture under a pressure of 20-150 MPa (depending on which technology is used). After this processing, the finished briquettes are delivered to the finished product warehouse for storage.

The purpose of the fuel and the equipment used are the main factors affecting the size of the particles, the level of humidity and the amount of pressure under which they turn into briquettes. At the same time, energy consumption finished product directly depends on the quality of raw materials. It is important to use exactly the fine fraction of anthracite, and not brown or other types of coal. For strength, the addition of mineral or organic additives is acceptable.

Coal briquetting press

Coal briquettes can be pressed in two ways depending on what equipment for briquetting is used:

• stamp press. Filled with heated charcoal mixture special shapes, in which it is compressed with a force of 100-120 MPa. After cooling, the briquettes are packaged. The finished product looks like bricks or cylinders with holes, it can look like "pills" or "pillows". This manufacturing method is suitable for the production of briquettes in large quantities due to high energy and financial costs.
• extrusion machine. In this case, the plastic coal mass is pressed through the matrix by a press. Briquette screw pressing (pini-kei) of coal dust has a cylindrical shape, resembling a "sausage", with a calibrated hole in the middle. The technology is less expensive, but also less productive.

Technology for the production of briquettes for industrial use involves the addition of cement, oil-bitumen mixture, liquid glass and others. In metallurgy, the use of these substances is permitted. But it is impossible to buy coal briquettes with oil bitumen for heating a dwelling according to the requirements of the SES.

Briquetting coal at home

For briquetting coal at home, industrial technology is not suitable. High price equipment for the production of coal briquettes, high energy costs, the need to obtain a huge number of permits from government agencies at times increases the cost of finished products. But for the purpose of heating a small private house, there is no need to organize large-scale production. For the manufacture of 3-4 tons of briquettes (winter stock), it is quite possible to get by with improvised means.

Equipment for briquetting at home

The easiest way, which was well known to our great-grandfathers:

• Coal dust is mixed with clay in a ratio of 10:1 with the addition of a small amount of water to form a thick mass. Clay is a safe binder that will prevent the briquettes from falling apart. It is important to thoroughly mix all the components of the mixture. For this purpose, a construction mixer is often used.
• Next, the solution is poured into molds. It can be both special containers and used inventory (old pots, buckets, boxes). If there are no containers, charcoal cakes can also be formed manually, as our ancestors did.
• After complete drying, briquetted coal can be sent for storage.

Despite the fact that, according to the production technology, the mixture is dried, during home briquette preparation, the mixture is moistened. In this case, do-it-yourself coal briquettes have the following distinctive features:

• Imperfect form.
• Different levels of humidity and, consequently, heat transfer.
• Low strength, which does not allow transporting briquettes.

Homemade coal briquette

But these properties do not prevent low-cost products from burning well, especially compared to sintered dust. This option is much more convenient and practical.

And if you still want to somehow automate the process, then you can follow the example of home craftsmen and independently manufacture equipment similar to production:

• Machine that allows you to make briquettes by hand. Instructions on how to make a machine are easy to find on the Internet. For manual pressing, a unit designed for home production bricks. The materials that allow welding the frame are profile pipe and a corner 40 * 40 mm. A receiving hopper is mounted on top. A manual mechanism for briquetting the mixture into rectangular or cylindrical products is attached to the side. Technology:
  • Raw materials are crushed to the maximum. The fine fraction ensures the strength and quality of the briquette.
  • Adding water will make the mixture sticky to your hands. It is permissible to add clay in a small amount in order to slightly increase the ash content of the fuel.
  • Next, the mixture is poured into the bunker, from where the mold is filled. The briquette is squeezed out by pressing the lever.
  • The reverse movement of the lever causes the briquette to be pushed out of the mold. It is removed and placed in the sun to dry.
• Screw press where products are briquetted by extrusion. In this case, the financial costs of assembling the machine, as well as its productivity, will be greater. You will need:
  • Thick-walled steel pipe for the manufacture of the body. Inside, it is machined according to the desired screw size.
  • Auger made of high strength carbon steel.
  • Matrix with one or more holes of the same material.
  • Electric motor with a power of 4 kW.
  • Belt drive (minimum 3 belts).
  • Receiving bunker.

Technology for the production of coal briquettes without a binder

It is better to entrust the manufacture of the body, matrix, screw to a good turner. It is important that the diameters of the pulleys provide a screw speed of no more than 200 rpm. The motor must be grounded before connecting it to the household power supply.

Production technology:

• The raw material is crushed and mixed with water.
• When the engine is on, the mixture is loaded into the bunker.
• Appearing "sausages" are cut into pieces of the desired length and laid out on a rack to dry.

It is important to know that the presence of through holes in the finished briquettes contributes to better combustion and greater heat transfer.

conclusions

According to the manufacturers of coal briquettes, the calorific value of this type solid fuel even more than other varieties. Theoretically, this statement can be quite realistic due to the fact that only when burning 1 kg of anthracite, you can get 7.7-8 kW. In terms of specific heat, firewood and wood briquettes lag far behind, releasing only 5 kW/kg.

However, an analysis of the feedback from the owners of solid fuel boilers on thematic forums shows that the demand for coal dust briquettes is lower than for wood, for several reasons:

• With their help, it is difficult to melt the boiler and when burned, coal gives off little heat.
• Before and during combustion, an unpleasant odor remains in the room.
• Briquettes lose their shape, crumble heavily during transportation.
• Lots of ash.

Combustion of coal fuel in briquettes

A large number of negative reviews(about 70% of the total) can be explained by the fact that manufacturers use low quality raw materials in order to get more profit. They briquette mixture, sludge and other types of coal unsuitable for space heating, and add excess substances for the mass. Briquettes made really from anthracite are hard to find. The main feature is the rich black color of the products.

Conclusions are clear:

• It is better to make coal briquettes on your own.
• For production, it is necessary to buy high-quality raw materials.
• If it is possible to purchase only low-calorie grades of coal, pressing is not economically feasible. Although burning low-quality briquettes along with firewood will reduce heating costs.

Yes, home-made coal briquettes are very different from factory counterparts: they crumble during transportation, are wet, and give less heat. But this way you can control the quality of the raw materials used, the presence and quantity of additives. Both in the boiler and in the stove, “homemade” briquettes burn well, much better than dust, which is simply baked into the cake. In addition, for the price, home-made cylinders, bricks or "sausages" are much more profitable.