ENERGY RECOVERY UP TO 25 kW/h

FROM THE PRECONDITIONER CHIMNEY 

In an extrusion plant, the flour mix is pre-treated in the preconditioner before being introduced in the extruder. During this treatment the flour is cooked with water and steam.

The flour is introduced at room temperature and is later brought up to 90 <100°C, which is deemed the ideal temperature to carry out the following treatment.

Pre-cooking of the extruded flour is carried out in the preconditioner by introducing water and steam.

To ensure good results, the amount of steam that is introduced is higher than the amount that the ground cereals absorb during gelatinization; this is essential so that they can be attacked by digestive enzymes.

The excess quantity is discharged through the chimney pipe located in the head part of the preconditioner.

In the long run, the room where the extruders are located would be made unlivable by the steam. Therefore the problem is often solved empirically by connecting the chimney pipe to the suction pipe that transfers the kibble from the extruder head to the dryer. However, this solution has a few drawbacks:

a) It entirely wastes the energy that has been spent on the production of steam which is not entirely used for cooking and hydrating cereals;

b) Water is introduced into the drying cycle and will have to be evaporated again, leading to a further waste of energy;

c) A given quantity of flour which has not been thoroughly pre-treated could be sucked in by the system and contaminate the finished product.

As a result of measurements made during production, it has been found that the energy wasted from the exhaust pipe through the chimney amounts to 25 kW for a 10 t/h extruder!

CRISTIANO TORRE ENGINEERING has designed, built and finalized a system that allows to completely suck in the steam discharged from the chimney and use it to heat water that can be used:

  • to feed the preconditioner itself, thereby improving the pre-cooking process in terms of gelatinization quality and energy consumption, as the steam introduced must not heat the watery part of the process;

  • to feed any process which requires hot water, upon completion of a micro-filtration treatment;

  • for its ideal use, that is to feed the wet extrusion waste recycling system TORRE type RSE2000VE using hot water.

  • to feed the bin washer using hot water.

SYSTEM DIAGRAM

A  – Inlet of extrusion flour at room temperature

B – Outlet of the treated flour at a temperature of 90 <100 ° towards the extruder

X – Inlet of saturated steam for hydration and cooking towards the distribution ramp

Y – Discharge of active steam due to failed flour absorption

– Stainless steel ‘Venturi’ DN 65. Suction rate: 170 m3/h

D – Hot water delivery (up to 90 ° C) to the preconditioner or delivery for other use

E – Water loading

M1 – Circulation pump  with 'Venturi' circuit 7.50 kW

M2 – Hot water delivery pump

THREE SKID SYSTEMS CONNECTED TO 3 EXTRUSION LINES

SINGLE SKID SYSTEM

VENTURI WITH EXTRACTION HOOD MOUNTED ON PRE-CONDITIONER

ASPIRATION HOOD MOUNTED ON THE CHIMNEY PIPE OF THE PRE-CONDITIONER

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