CACAO DRYING-PROCESS
GENERAL DESCRIPTION This drying system is generally employed in order to dry up the working refuses such as shavings, olive husk, etc... that is the drying of eatable materials such as cacao, coffee, chestnuts, etc... The material drying occurs inside the cylinder of a circular drier, both through the immission of air overheated in its inside, produced by a thermal-exchange battery and an axial electrofan set in countercurrent regarding the material advancement in the cylinder; and through the heat produced by a series of batteries set inside the cylinder and transmitted on the material during its advancement. The material is loaded in the cylinder through a tape, and advances in its inside; the cylinder rotation occurs through an electronic motorvariator which manages the turns/min. number and therefore the material permanence in its inside. A stellar valve, connected under the terminal to the cylinder feedbox allows the unloading of the material. An external thermal system, provided with pump to flow again the overheated water, manages all the thermal-exchange batteries of the system. All has been connected to the general control switchboard.



 
The elements of the system are: · Circular drier made up of: · Cylinder support structure; · Transmission electronic motorvariator+ Inverter; · Chains, pinions and cast iron wheels transmission system + polyurethane; · Sheet cylinder Ø=2000 in diameter and L=8000 millimeter in length ; · removable exchange batteries (n° 4) from 100.000 Kcal/h a piece; · System for the material transport; · Rotating joint system (for pressures up to 6 bars); · Load and unloading material terminals from the cylinder; · Material load tape conveyor; · Material unloading stellar valve; · Exchange battery from 300.000 Kcal/h; · Overheated water generator from 600.000 Kcal/h; · Overheated water flowing again pump; · Axial electrofan for warm smokes; · Regulation shutter; · Control and management electric switchboard

TECHNICAL DESCRIPTION OF THE CIRCULAR DRIER The support structure, constituted mainly by structural steel, is made up of an inclined support plan, bolted on a support loom with protection net and a support for the transmission electronic motorvariator and the inverter fixing, which adjusts the cylinder turns/min. number; on this inclined plan has been fixed a chain transmission system made up of axles, joints, pinions and cast iron wheels + polyurethane, that allow the drying cylinder rotation. The drying cylinder is made up of sheet modules in calendered thickness, with Øint=2000 inner diameter and Lt=8000 millimeter total length, and it is supported on the wheels of the transmission system (inclined), which slide on guides calendered to the outside of the cylinder. Inside the cylinder a guide system for the insertion of n° 4 removable exchange batteries has been fixed, cross positionated. The removable exchange batteries from 100.000 Kcal/ha piece are constituted by a compact series of steel pipes for high pressures, connected to the extremities to one collector; they are connected between them by crossed collectors, which are connected to rotanting joints that allow the passage of the liquid during the cylinder rotation and the batteries.



 


To the cylinder extremity, two terminals have been mounted and fastened to the support structure: one is for the material load, made up of a pierced net for the outflow of the warm air generated by the exchange battery in the opposite part and by the entrance of a tape conveyor that directly unloads the material inside the cylinder; the other terminal is for the material unloading, under which a stellar valve for the regulation and the holding of material unloading has beeb set. The thermal-exchange battery from 300.000 Kcal/h, connected to an external thermal system and fixed to the unloading terminal by connection, heats the air flux generated by a axial electrofan connected to this battery. The air amount is regulated by a shutter fastened over the electrofan, with a protection net. All is managed by feeding switchboard.


 
DIFFERENT ELEMENTS SPECIFICATIONS Double screw without end electronic motorvariator: · slow revolutions: from 0,9 to 7 to a minute/1 ' · engine power: 3 kW - 4 V.230/400 poles - 50 Hz - IP55 N° 4 thermal-exchange batteries to in-line piping sheaf (steel gas pipes for high pressures), inside the cylinder. Values for every battery: · Potentiality: 100,000 Kcal/h cad. · dimensions: 7.700 x 980mm - 60 millimeter in thickness · connections: n° 2 from 2" · tubes: n° 16 from 1"1/4 · collectors: n° 2 from 2" · fluid in the pipes: water - vapor · inner volume pipes: 530 lt · Weight: ~ 700 Kg cad. Thermal-exchange battery (copper pipes/aluminum fins): · Potentiality: 300,000 Kcal/h · dimensions: 2.000 x 2.000mm - 300 millimeter in thickness · Øconnection: 2" · vent-hole valve: 1/2" · unloading valve: 1/2" · Weight: 120 Kg Fluid inside the pipes · fluid in the pipes: water · fluid capacity: 100 mc/h · inner volume batt.: 70 lt






 


Helicoidal axial fan: Employment: suitable for smoke suction, dusty and humid air, in applications with radiators for the paper drying, as well as wool, paste, bricks, etc... Double flange sheet-steel drum, light alloy die-casting impeller (sparkproof), connection to the engine carried out by race pulleys and trapezial belts. The closed type three-phase V. 380 - Hz 50 electric engine, class "H" insulationg for high temperatures, IP 55 protection for environmental conditions of the tropical type with tropicalized 100% humidity, special bearings with lubricating fat for high temperatures. Operating temperatures: from -20°C to +70°C The above mentioned specifications refer to the working with air to +15°C and 760 millimeter of Hg barometric pressure: · air capacity: 35.000 mc/h · air speed: 6,6 m/s · absorbed power: 5,5 kW · engine turns: 1.450 g' /min · total weight: 140 Kg · noisiness: 80 dB (a) Overheated water generator working with wood-shaving. The overheated water generator working with wood-shaving belongs to the horizontal type, smoke pipe semiflux · Potentiality hearth: 600,000 Kcal/h · Max operating pressure: 2 ATE · smoke turns: 3




 
The generator body consists of the following structures: · horizontal hearth reinforced with ring compensator, if required · Angle plating welded to piping plates · Angle piping plates welded to the hearth · Piping-sheaves constructed with Fe 35-2 UNI 663-68 or ASTM or 106 carbon steel pipes welded to the piping plates by previous expanding. All the sheets are in P 275 NH UNI 10028/3 carbon steel. The walking pace is to autoclavic holding. The inner hearth head, in correspondence of the front smoke case, is shielded by refractory thermal cradle. Hearth and ash pit are inspectable by a door with wide dimension for the firewood loading and a regulation door for the feeding air in the subgrille. The front smoke chamber is equipped with two hinged doors, strongly insulated, with quick opening for the piping-sheaves check. The reversible chamber, belonging to the drying type, and the posterior smoke chamber are closed by an hinged door, shielded by refractory to elevated percentage of alumina and insulated by thick wool rock layers, quick opening for hearth check, reversible chamber, first and second piping sheaf, posterior smoke chamber. It is therefore easy to clean the piping-sheaves with the appropriate cleaning-rod and then to remove ashes from the hearth, the reversible chamber and the posterior smoke case. The plating heat insulating is realized with thick rock mattresses covered by a sheet-steel shell. The generator is supported by two saddles that rest on a bedplate in structural steel. The generator is covered in the front part, automatic burner zone, with refractory concrete to high percentage of alumina. The included accessories are: · N° 2 safety valves with specifications according to the ISPESL and PED norms · N° 2 started flux valves in cast iron for the exhaust · N° 1 operational thermostat · N° 1 safety thermostat · N° 1 thermometre . N° 1 safety manostat · N° 1 manostat protection siphon · N° 1 quadrant manometre with three-way cock siphon · N° 1 PN16 DN50 straight started flux valve · N° 1 Alpha 10 Ø 50 valve for exhaust · 3 N° siphons · cleaning-rod for pipe cleaning Burner, AUTOFOCO type, is installed on the boiler, suitable to work with sawdust and wood-shavings, with hearth realized with special cast iron grilles with multiple nozzles in order to render optimal the primary air flux, hearth bedplate in steel with elevated thickness, including pipe and feeding cochlear, motorvariator for the fuel capacity regulation, electrofan and relative channels for the the primary and secondary air intake with regulation through manual shutters. 2 bars closed expansion box provided with regulation and control devices and with switchboard Mechanical smoke extractor provided with engine and fixing flange Smoke exhauster multicyclon for the captation to low speed of aeriform residual combustion products, with sheet-steel self-carrying structure, including doors for the periodic cleaning and maintenance, pedestals, collection cinders tanks. Series of smoke connections from boiler to simple cyclone and to fireplace Safety valve set to 3 bars Fireplace in zinc-plated steel with bedplate, cleaning door and joints for the connection to the boiler Overheated water flowing againg pump from the boiler to the different batteries · water capacity: 100 mc/h · load loss: 15 mt of H2O column control ignition system for the steady check of the regular ignition of every working cycle, made up of temperature survey feeler for fireplace smokes, electronic temperature thermoregulator, safety timer and for lacked ignition stop. switchboard is suitable to manage the entire system during the different drying-process phases (fan and relative reversibility, exhaust stellar valve, electronic motorvariator, etc...). The switchboard is constructed in compliance with the norms in force and in particular to CE norms; its construction is executed in IP 55. Special devices adopted in the course of construction of the electrical circuits inside the board, guarantee just the same, greater security, reliability and inspection, as well as being predisposed for the connection of electronic control equipment. Inner electrical system for heating, ventilation, expulsion and humidification. The electrical system essentially consists of connections between the switchboard and the different elements of the system, connected between the check equipment and the switchboard.






 
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