Cane Sugar Extraction Process

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Questions and Answers

What is the main purpose of the chevron grooves cut on the v-groove rollers?

To increase the pressure during extraction

To facilitate the addition of water for extraction

To prepare bagasse for combustion

To assist in gripping the bagasse for better feeding (correct)

Why do the sizes of grooves decrease from the first to the last mill?

To accommodate larger pieces of sugar cane

To match the decreasing size of bagasse particles (correct)

To shorten the extraction process in later mills

To enhance the temperature of the extraction process

What role do the perforated rolls play in the extraction process?

They increase the viscosity of the juice

They enhance drainage during juice extraction (correct)

They crush the bagasse into smaller pieces

They apply additional heat to the bagasse

What is one of the main objectives of grooving in the milling process?

To break up the bagasse for better juice extraction Signup and view all the answers

What happens to the probability of juice reabsorption as bagasse encounters the feed roller?

It becomes high due to compression Signup and view all the answers

What does the Cane Preparation Index (CPI) measure?

The extent of rupture of cells in prepared canes Signup and view all the answers

What is the main objective of the extraction process in cane processing?

To extract the maximum juice content from the prepared cane Signup and view all the answers

In the context of cane milling, what is the purpose of the trash plate?

To separate the juice from the cane Signup and view all the answers

How does a 4 roller mill differ from a conventional 3 roller mill?

It includes an underfeed roll for better feeding Signup and view all the answers

Typical Preparation Index (PI) values for cane preparation range from:

80% to 94% Signup and view all the answers

What is produced as a byproduct of the extraction process?

Bagasse with minimal moisture Signup and view all the answers

What type of objects does tramp iron refer to in cane processing?

Stray metallic particles or objects Signup and view all the answers

Which configuration of a mill provides better feeding efficiency?

4 roller mill with underfeed roll Signup and view all the answers

What is the primary advantage of steep-angled grooves in mill grooving?

Enhances drainage and extraction Signup and view all the answers

What type of grooves are generally found in the first to third mills?

Coarse or large grooves Signup and view all the answers

How does the width of Messchaert grooves affect juice drainage?

Wider grooves decrease drainage effectiveness Signup and view all the answers

What is one disadvantage of using the second method of providing Messchaerts?

Increases tooth fracture tendency Signup and view all the answers

In which zone does the bagasse undergo maximum pressure at the feed roller?

Zone AB Signup and view all the answers

What is the recommended pitch for Messchaert grooves?

A multiple of the main grooving Signup and view all the answers

What is the pitch range for rough grooves used in extraction?

56 mm to 76 mm Signup and view all the answers

Which statement is false regarding small grooves in mill grooving?

They should have a pitch of more than 38 mm. Signup and view all the answers

What is the purpose of the trashplate in the juice extraction process?

To direct bagasse flow to the discharge Signup and view all the answers

Which groove type is associated with better drainage?

Fine Grooves Signup and view all the answers

What performance advantage do rough grooves provide?

Better tearing action Signup and view all the answers

What is the impact of a small pitch and small angle on tooth strength?

Weakens tooth strength Signup and view all the answers

Which type of conveyor is typically used to transport bagasse between mills?

Slat or Apron Conveyor Signup and view all the answers

Tooth strength is a concern at which configuration?

Small Pitch and Small Angle Signup and view all the answers

What groove angle range is recommended for shredded cane with a pitch of 38 mm?

35˚ to 55˚ Signup and view all the answers

What type of movement do Rake or Drag Type Conveyors utilize?

Dragging movement Signup and view all the answers

What is a primary consequence of uncontrolled burning of canes?

Infection by microorganisms Signup and view all the answers

Which type of cane deterioration is caused by bacterial action leading to dextran formation?

Sour canes Signup and view all the answers

What is the result of enzyme-mediated sucrose inversion?

Formation of glucose and fructose Signup and view all the answers

Which statement is true regarding the preservation of cane quality post-harvest?

Stale canes are free from bacteria. Signup and view all the answers

What is the effect of polysaccharide formation in deteriorated cane?

Delays in processing Signup and view all the answers

Study Notes

Tramp Iron

Refers to stray metallic particles, including pieces of knife-blades, sling-hooks, broken pieces of slings, monkey wrenches, bolts, and nuts.

Cane Preparation Index (CPI)

Measures the extent of cell rupture in prepared canes.
Typical CPI values range from 80% to 94%.
Determined by mixing cane and water for a set time, then measuring the dissolved solids concentration in the extract (Brix by leaching).

Extraction

The main objective is to extract the maximum juice content from shredded or prepared cane.
This involves successive squeezing to produce bagasse with minimal moisture content.

Conventional Mill

A traditional 3-roller mill compresses prepared canes to extract juice and expel bagasse.
A trash plate separates the feed and discharge rolls.

Mill Configuration

A 4-roller mill has an additional underfeed roll, improving bagasse feeding.

Mill Grooving

Steep-angled grooves (35°) enhance drainage and extraction, reducing bagasse moisture.
Coarse grooves (45° to 55°) are used for initial shredding and tearing (found in the first to third mills).
Small grooves (less than 38mm pitch) improve juice drainage for well-prepared canes (found in the 4th to last mills).

Messchaert Grooves

Also known as "juice grooves," they aid juice drainage, typically located on feed rollers.
Dimensions: 3-6.5 mm width, minimum 20 mm depth (typically 25 mm), with a pitch that's a multiple of the main grooving.
Wider grooves can hinder drainage.

Messchaert Groove Placement

Two methods:
- Removing a tooth and placing the groove in its location.
- Cutting the groove between two teeth.
The second method avoids loss of a tooth, but lateral drainage is less effective, making it suitable for coarser grooving.

Action of Messchaerts at the Feed Roller

The most pressure on the bagasse is at the feed roller, where juice is extracted.
Juice can escape either forward beyond the trashplate, or backward.
Both directions encounter compressed bagasse, increasing the chance of juice reabsorption.

Chevron Grooves

Cut on v-groove rollers to improve bagasse gripping and feeding.

Perforated Rolls (Lotus Roll)

Drilled holes at the bottom of grooves connect to longitudinal drains on the side of the roll.
Enhance drainage (top rolls) and are suitable for the first and second mills.

Variation of Grooving

Groove size typically decreases from the first to the last mill.
- This aligns with the fineness of the bagasse which becomes finer as it progresses through the mills.
- The initial mills require coarser grooving for maximum disintegration, benefiting later mills.

Criteria for Choosing Roll Grooves

Dimensions: Fine grooves (7 mm to 38 mm pitch), Rough grooves (56 mm to 76 mm pitch).
Performance: Fine grooves offer better drainage, while rough grooves provide better tearing action.
Groove Angles: Small angles improve drainage, larger angles reduce wear.
- Knifed Cane: 76 mm pitch for the first two mills, then 26 mm, groove angles 40° to 55°.
- Shredded Cane: 38 mm pitch, groove angles 35° to 55°.
Others:
- Small pitch and small angle can break easily when hard objects are milled.
- Large pitch and large angles are stronger, but have higher reabsorption.
- Pressure feeder rolls are typically grooved at 38 mm to 56 mm with angles of 35° to 45°.

Intermediate Carriers & Chutes

Conveyors move the bagasse from the discharge of one mill to the feed of the next.

Types of Intermediate Carriers

Slat/Apron Conveyor: Uses slats or plates (steel, wood, etc.) mounted on roller chains.
Rake/Drag Type Conveyor: Uses chains with welded tines that drag the bagasse.

Cane Deterioration

Factors include invasion of microorganisms (e.g., dextran-forming bacteria), sucrose inversion by enzymes, acidic hydrolysis of sucrose, uncontrolled burning, cut cane ends, and canes lying in wet muddy areas.

Sucrose Inversion

Sucrose breaks down into glucose and fructose.

Polarimetry

Sucrose is dextrorotatory (rotates polarized light clockwise).
Glucose and fructose are levorotatory (rotate polarized light counterclockwise).

Cane Deterioration (Burning)

Burned canes are more susceptible to infection.
Burning removes the wax coating, cracking the rind and allowing bacterial entry.
Severe burns can leak juice, providing a breeding ground for bacteria.

Cane Deterioration (Sour Canes)

Canes deteriorate through bacterial action, forming dextran.

Cane Deterioration (Stale Canes)

Canes stored without bacterial infection form sarkaran.
Both dextran and sarkaran can cause processing delays and losses.

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Description

This quiz covers the essential concepts related to cane sugar extraction, including tramp iron, Cane Preparation Index (CPI), and various mill configurations. Understand the mechanics of conventional mills and the importance of juice extraction techniques. Test your knowledge on optimizing cane processing for maximum efficiency.