BRMU9000300Y1 - ROTATING SCREEN FOR SEPARATING MINERAL IMPURSES IN THE SUGAR COAL INDUSTRY - Google Patents

Abstract

rotary sieve for the separation of mineral impurities in the sugar and alcohol industry, it consists of a rotating sieve (1) with only an internal helicoid (2) that allows the movement of low density crude straw along the equipment that by means of Cyclic movements promote the separation of the solid waste through the perimeter mesh (3) towards the discharge hopper (4), so that the sieve (1) can be used to separate the solid waste from the initially discarded sugar cane in the cleaning process. dried on sugar cane feed tables.

Description

(54) Title: ROTATING SCREEN FOR SEPARATION OF MINERAL IMPURITIES IN THE SUGAR AND ALCOHOL INDUSTRY (51) Int.CI .: B07B 1/18 (73) Holder (s): CTC - CENTER OF TECHNOLOGY CANAVIEIRA S / A (72) Inventor (es) ): FRANCISCO ANTONIO BARBA LINERO; CELSO ANTONIO FURLAN (85) National Phase Start Date: 09/03/2010

1/10 “ROTATING SCREEN FOR SEPARATION OF MINERAL IMPURITIES IN THE SUGAR ALCOHOL INDUSTRY”

This descriptive report deals with the patent application for a Utility Model of an unprecedented “ROTATING SCREEN FOR SEPARATION OF MINERAL IMPURITIES IN THE SUGAR ALCOHOL INDUSTRY” consists of a revolutionary equipment to be used in sugar and alcohol plants whose construction allows extracting mineral impurities the straw to be burned in the boilers or the sugar cane blades, initially discarded in the dry cleaning process, to be reused in the mill.

The increasing increase in the amount of sugarcane harvested mechanically and without prior burning made it necessary to make some adjustments / modifications to the cleaning systems before processing in the sugar and alcohol industries.

Mechanized harvesting, without burning, is an irreversible process, mainly due to the environmental and economic factors involved. From an environmental point of view, specific laws and agreements between state and plant governments increasingly restrict the release of burning before harvest. Economically, mechanized harvesting and cutting costs have been shown to be lower than manual cutting costs with mechanical loading.

Sugarcane harvested mechanically without prior burning arrives in the industry in the form of awnings with foreign materials, called impurities (vegetables and minerals). Vegetable impurity is the composition of green leaves, dry leaves and pointers and is commonly called “cane straw”. Mineral impurities consist primarily of the earth that is loaded together

2/10 with the rest of the material (cane and straw straws) by the action of mechanical harvesters.

In the mechanically harvested cane, hydraulic cleaning is not recommended, according to old practices, since the losses of sugar in the washing are high. Consequently, the elimination of washing significantly reduced the water intake by the plants, which adds to the elimination of previous sugarcane burning in the field, in order to obtain environmental gains.

These facts led to the research and implementation of new sugarcane cleaning techniques in the industry to remove vegetable and mineral impurities, basically motivated by two main factors:

> Seeking to improve the quality of the cane to be processed, reducing the fiber content, and thereby providing greater grinding capacity and less sugar losses in the cleaning process;

> Use of straw as fuel to be burned in the boilers in order to generate additional energy, in which case the straw needs to be conditioned (cleaned and crushed) to bring its characteristics closer to the particularities of the sugarcane bagasse, which is the traditional fuel.

In the current state of the art, in industries in general, rotary sieves are used in various stages of processes aiming at the separation of different materials.

In turn, the sugar and alcohol industry already uses some sieves to separate mineral impurities, such as the MU 8001856-4 Static Circular Sieve applied in the sieving of liquid fluids used in chemical processes, with the objective of promoting the separation of solids as

3/10 bagacilho, mineral material, stones, sand, crystals and other solid polluting elements, which works in a static way and has a specific granulometry of variable retention according to what is desired in the chemical process, depending on the type of mesh used in sieve, being preferably used in the processes of obtaining sugar and / or alcohol, in the stage after the crushing of the cane and / or in the stage immediately after the decantation of the clarified juice, in order to optimize the whole process, obtaining a bigger and better cleaning for the next steps in the process.

On the other hand, the sieves used to separate the mineral impurities from the crushed straw are also known. Such sieves have the constructivity formed by shafts and internal components that cause problems of clogging, when applied to raw straw (without crushing), due to the low specific mass, which makes the flow difficult. As crushed straw is a material with a higher specific mass, it is easier to handle, so a less elaborate sieve is used as mentioned above.

However, no equipment is yet known for sifting and separating mineral residues from straw before crushing, since this material is of low density and difficult to handle.

In time, the biggest advantage of separating the mineral impurities from the cane straw, before crushing (raw straw), lies in the fact that it prevents the premature wear of the equipments that make this crushing possible, reducing maintenance and increasing its useful life.

Aware of the state of the art, its gaps and drawbacks, it was that the inventor, a person used to the material on canvas, after studies and research, created the “ROTATING SCREEN FOR THE SEPARATION OF MINERAL IMPURITIES IN

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SUCROALCOOLEIRA INDUSTRY ”in question, without any type of internal component except for the helical profile that facilitates the movement of raw straw (low density) inside, which promotes a cyclic movement of coming and going, capable of separating impurities solids from the straw or from the cane blades lost from the cleaning process.

It is known that dry cleaning of sugarcane with ventilation is one of the techniques used to separate vegetable and mineral impurities from the blades. Cleaning cane and conditioning the straw to bring it closer to the bagasse's particularities requires a series of new equipment, including the sieve claimed here.

The cane cleaning system with ventilation can be implemented with different configurations, such as:

> Dry cleaning system on a cane feeder table;

> Cleaning system for the transfer of cane between belt conveyors.

In summary, the innovative sieve can be applied in two situations:

> Separation of mineral impurities from cane straw to be used as fuel in boilers - in this case, mineral impurities are undesirable for cane straw crushing equipment, and this procedure is necessary to make the straw granulometry similar to that of bagasse. In addition, the mineral impurities present in the straw can cause internal fouling in the boilers, increase the emission of particulate matter in the chimneys and increase the frequency of cleaning the boilers.

> Reuse of the cane pellets that would be discarded in the mineral impurity separation system in cane receiving tables - the

5/10 mineral impurities together with the cane pellets removed from the receiving table are sent to the sieve for separation. Mineral impurities fall by gravity in a hopper, returning via road transport to the field and the reeds are reused, sent to the mill or diffuser.

Sieve performance tests indicated cleaning efficiencies in the order of 90% on a dry basis with losses of organic matter along with mineral impurities of 3%. This performance refers to the sieve designed to separate the mineral impurities from the cane straw.

Below, for a complete visualization of this request and to better elucidate the descriptive report, the innovation is explained with reference to the attached drawings, in which they are represented in an illustrative and non-limiting way:

Fig. 1: Side view of the rotating sieve to separate mineral impurities in the sugar and alcohol industry;

Fig. 2: Front view of the rotating sieve to separate mineral impurities in the sugar and alcohol industry;

Fig. 3: Perspective view of the rotating sieve to separate mineral impurities in the sugar and alcohol industry, showing use;

Fig. 4: Detail in perspective of the helicoid of the innovative sieve;

Fig. 5: Schematic view showing a cane feeder table, suitable for dry cleaning, where the innovative sieve is used both in the recovery of lost strips in the separation of mineral impurities and in the separation of mineral impurities from cane straw;

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Fig. 6: Schematic view showing the dry cleaning of cane between belt conveyors, where the innovative sieve is used to separate the mineral impurities from the cane straw.

The “ROTATING SCREEN FOR SEPARATION OF MINERAL IMPURITIES IN THE SUGAR-ALCOHOL INDUSTRY”, object of this Utility Model Patent application, consists of a rotating screen (1) with only an internal helicoid (2) that allows the movement of raw straw , of low density, along the equipment that by means of cyclic movements promote the separation of the solid residues through the perimeter screen (3) towards the discharge hopper (4), said sieve (1) being able to be used in the separation of the solid residues from the cane blades initially discarded in the process.

More particularly, the equipment claimed consists of a horizontal rotating drum type sieve (1) containing a continuous internal helicoid (2) that directs the raw straw or cane pellets, depending on the use, in a given direction of discharge.

The helicoid (2) is crucial to define the capacity, the flow of the material and the separation efficiency. A metallic screen (3) is attached to the internal structure (5), without burrs or protruding elements, covering the entire outer surface of the drum.

The sieve is mounted horizontally with a slight inclination, preferably 5 ° to facilitate the flow. Another difference is the absence of an internal drive shaft, because due to the physical characteristics of the cane straw and the blades, any internal element could restrict the flow and hinder the flow of the material. This feature requires the equipment to be

7/10 supported externally, on the rollers (7) that serve as drive and support, positioned on the structure (6). Therefore, the support and external activation of the sieve (1) consist of tracks (8) in which rollers (7) actuators and support ensure the support and rotation of the drum. A wheel (9) at the front ensures support in the longitudinal direction of the equipment.

In this way, raw cane straw or cane blanks with mineral impurities enter the sieve (1) through a feed conveyor (10) installed at one end (A). After entering the inner part of the basket, the material remains sliding on the canvas (3), in a cyclic back and forth movement, removing the mineral impurities present until its exit through the other end (B) where the material is unloaded on another conveyor ( 10A). The helicoid (2) acts in the internal direction of the straw and the blades, and the height and pitch of the same are responsible for defining the capacity together with other factors such as basket diameter and rotation.

The mineral impurities separated from the cane straw and the blades fall by gravity into the hopper (4) and are subsequently sent to the fields.

In the dry cleaning system on a cane feeder, the sieve equipment is used in two stages of the process.

In the first stage, the cane received by the mill is unloaded on a table (figure 5) with an inclination that varies between 45 and 48 °. The cane load of the truck (12) is placed between the unloading ramp (11) and the rising surface of the table (T). In this, metal cleats attached to the chains and driven through an axis (13) positioned at the top cause the cane to move on the table, causing the cane mass to move in the direction

8/10 upward and is subsequently discharged on a metallic conveyor (14) towards the mill or diffuser.

In table cleaning, openings installed in the discharge (11) and rising (T) ramps facilitate the removal of mineral impurities that are later removed via belt conveyors (17).

At the bottom of the table, other openings are necessary for the passage of the taliscas. In these openings, some cane blanks can be diverted to the conveyor (17) together with the mineral impurities. For the recovery of these sheets, the sieve claimed here is used.

In this first step, its function is to reuse the stalks of sugar cane that are diverted from the main stream, redirecting them to the mill or diffuser, eliminating waste. As already mentioned, mineral impurities and blanks enter the sieve basket (1) at one end. Mineral impurities pass through the screen (3) of the sieve and are deposited in a hopper (4) to later be removed from the plant. The cane blanks are directed by the helicoid (2) to the end (B) from where they are sent to the mill or diffuser, via belt conveyors.

Returning to the layout of the feeding table (figure), when reaching the top of the table, the mass of cane falls by gravity on the metallic mat (14). In the fall trajectory, the cane is ventilated (15) to remove vegetable impurities and the rest of mineral impurities. Vegetable and mineral impurities removed from the main cane stream are directed into a chamber (16) and the clean cane follows on the metallic mat (14) towards the mill or diffuser. The belt conveyor (18) collects vegetable impurities (straw) and mineral impurities (earth), directing them to the straw conditioning phase. O

9/10 conditioning aims at the energetic use of vegetable impurities and includes the cleaning of straw and its crushing.

In this stage of the process a second sieve (1) is used to separate the mineral impurities from the vegetable impurities (paiha). After the sieve (1), the straw goes to the crushing equipment and is subsequently mixed with the bagasse to be used in the boilers. Therefore, the sieve (1) separates the mineral impurities from the plant impurities blown out of the cane stream during the ventilation process. As previously mentioned, mineral impurities must be removed from the straw to prevent crushing equipment from wear. In the boiler, large amounts of mineral impurities can cause scale and increase the frequency of cleaning furnaces and other gas cleaning systems.

Finally, in the dry cane cleaning system between conveyors (T1 and T3) (Figure 6), the chopped cane (C) without burning mechanically harvested received by the plant is unloaded on a metallic conveyor. This conveyor is transferred to a high speed belt conveyor (T1). Between the receipt of the cane and the metallic conveyor where the equipment for the "preparation of the cane" is installed before the actual grinding, unevenness is foreseen that promote the gravity drop of the cane flow. Normally these unevennesses are induced by the different heights of the belt conveyors (T1, T2 and T3). The chopped cane (C) with mineral and vegetable impurities receives air jets (19) in the unevenness, when passing between the belt conveyors. This jet directed from top to bottom promotes the cleaning of the cane and directs the straw and mineral impurities into a depressurization chamber (20). Clean cane (CL)

10/10 goes to the mill or diffuser. The straw (P) collected on the belt conveyor (21) has a large amount of mineral impurities and must be conditioned before being sent to the boilers. In the conditioning process, the sieve (1) is used only to separate the mineral impurities from the straw before crushing. The straw together with the mineral impurities enters one end of the sieve basket and the mineral impurities are eliminated through the screen. The clean straw comes out from the opposite end of the sieve, in a process identical to that described in the previous system.

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Claims (3)

CLAIM 1. Rotating screen (1) for the separation of mineral impurities in the alcohol industry, horizontally and preferably inclined 5 °, supported externally on the rollers (7) supported on bearings fixed to the 5 structure (6), containing a metallic mesh (3) attached to the internal structure (5) and, in addition, a feed conveyor (10) installed at one end (A), through which the raw cane straw with the mineral impurities enter the sieve (1), characterized by containing a continuous internal helicoid (2), a wheel (9) on the front, which guarantees stability in the 10 longitudinal direction, and be driven externally through tracks (8) in which the rollers (7) guarantee the support and rotation of the drum, separating by gravity the mineral impurities from the cane straw and the blanks and directing the impurities to the hopper ( 4). Petition 870180045806, of 05/29/2018, p. 8/8 1/3 FIGURE 2 2/3 FIGURE 3 FIGURE 4 3/3 FIGURE 5 FIGURE 6