Briquetting Promeco

The Promeco PES briquetting machine is the most simple, flexible, efficient and effective solution to the problems of densification / sintering.

The extreme flexibility of the machine allows processing of different materials. PES systems have been used successfully to treat:

• Mix of plastics, paper and cardboard, textiles and wood
• MSW dry fraction
• Industrial solid waste (similar to urban waste)
• Mix composed by the typical constituents of the dry fraction of municipal waste used as RDF (lightweight plastics, textiles, wood, paper and cardboard);
• car fluff

Principles of operation

The PES is a twin-screw extruder with short screws, that agglomerates the material in input combining the effects of pressure and mechanical friction, determining a significant increase the temperature of the material in the extrusion chamber.

The input materials - after pre-treatment operations, if any - is charged into the feeding hopper of the machine.
The bunker is equipped with a pair of augers, feeding the material to a vibrating table which meters the flow in input to the extrusion chamber. Here a  process of "thermo-mechanical disintegration" of the material takes place, by means of the heating and the partial disruption induced by mechanical friction. In particular, temperature increase allows for the dehumidification of the treated material, the removal of organic impurities, and the melting of the materials which can act as "glue" for the other (for example, plastics with low melting point, such as polyolefins ).
The motor is oversized, to obtain the best results even when dealing with "difficult" materials. However, in most situations, the total power available is used only to the extent of 60%.

Based on the readings from some level probes, the systems feeding the material are stopped in case of filling, and restarted when new material is needed.
For the production of briquettes or pellets, the materials are leaving the extrusion chamber through an extrusion die, the section of which is a function of the required features (size and shape), and is equipped with a hydraulic control system that controls the pressure. In the case of pellets, such a system is not necessary.
Extruded material comes out from the matrix in a continuous way, and a cutting system guarantees the adjustment of the length of the final product. Above the extrusion chamber and the cutting system is an aspiration system to collect any dust and vapours and send them to treatment.
The PROMECO EXTRUDER SYSTEM is designed to operate under heavy loads, and this determined the considerable strength and sturdiness of all the machine components, starting from its structure. Forces are balanced, and only the static weight of the machine is discharged to the machine structure, which must be positioned on a proper floor.
The cooling system of the gearbox, tightly bound to the Extruder, consists of an oil closed circuit.
The speed of main motor is adjustable, allowing the optimization of the screws rpm  according to the quantity of material actually treated and the desired characteristics of the output.

System flexibility

Waste is characterized by the inconsistence of its quality. Moisture, density, composition and size can vary significantly.
The PES system was designed to automatically compensate for any fluctuations, in order to maintain as stable as possible the production rate or quality of the output.

The main motor is generously oversized in order to maintain the production rate even in the presence of material more "difficult" to treat. Under normal conditions, however, is used 60% of installed capacity.

The control system, based on PLC, continuously monitors several parameters, including electrical power consumption and temperature of the extruded material, in order to adjust the operations of the machine accordingly.

The control action is based on this principles:

• Decrease in electrical power consumption: the speed of the augers of the feeding bunker is increased, in order to maintain a constant production rate
• Increase in electrical power consumption: the control system acts on the matrix of extrusion, by opening the top, allowing an easier flow of material.
• Decrease in the temperature of the material, below a desired value: the control system closes the matrix extrusion, decreases the speed of the augers of the feeding bunker, reduces the motor speed.
• Increase in the temperature of the material: the control system opens the extrusion matrix, increases the speed of the augers of the feeding bunker and increases the speed of main motor

Incoming materials

Non-reusable fractions MSW, Paper, Cardboard and Plastic

• Absence of metal fractions and aggregates with a diameter> 4 mm.
• Optimum size of about 4x4x1 cm.
• Average humidity 15% max up to 20-23% depending on the characteristics required for the briquettes.
• Homogeneous mixture of materials with minimum 25% of a low melting point plastics (LDPE polyethylene film).

Thermoplastic and thermosetting waste

• Absence of metal fractions and aggregates with size diameters> 4 mm.
• Reduced presence of foreign material.
• Particle size reduced by preventive grinding, shredding.
• Mixed plastics similar to heterogeneous melting point (low melting point / melting high)
• Polyethylene washed unwashed also mixed with other materials, polypropylene, PVC, ABS, Polycarbonate

Car fluff from auto shredder residues (ASR)

Material to process consists mainly of a mix of plastics, elastomers, rubber parts, textiles, protective coatings, electrical cables, glass, soil fractions and non-ferrous materials in general.
The requirements that such a mix must satisfy in order to ensure the effectiveness of the extrusion process are essentially:

• Minimal presence of metals, and absence of inerts with a diameter > 4 mm.
• Optimum particle size of about 40x40x10 mm, easily achieved with a pre-grinding.
• Max humidity up to 20-23% depending on the characteristics required for the briquettes / pellets.

Products

RDF, pellets & briquettes:

• The briquettes have different shapes, sizes from 40-200 mm, an average degree of compactness and high adherence. Briquettes can then be ground (in a shredder without grate) to obtain a mix of high density material with a variable size 5-80 mm, particularly suitable for fluidized bed furnaces.
• Specific gravity  between 0.4 and 1.2 kg / dm³.
• Moisture content ranging between 2 and 11% depending on the composition of the refusal to start.

  Benefits resulting from treatment with PROMECO Extruder System:

  • Strong decrease of the times of densification of the product.
  • Fewer machines to install and manage, and relative reduction of investment costs
  • Small areas occupied
  • Minor electric power installed and used
  • Simplified Maintenance
  • Increased productivity and versatility of the system
  • Low running costs and operation of the plant

Production capacity

Briquettes:

Capacity changes depending on the characteristics of the treated waste and the desired output; it can reach 3,000 kg/h.
With waste having  specific weight of 200-250 kg / m³, humidity less than 15%, consisting of paper and plastic (50% -50%), size of about 40 mm, produced in output with Ø 150 mm, density 1, 1 kg / dm³, the treatment capacity of a machine PROMECO EXTRUDER SYSTEM type 600 is about 2,500 kg / h.