Raw Sugar Making Process with Flow Chart and specifications

Know About Raw Sugar Manufacturing Process

This sugar article discussed raw sugar definition, the basic steps for the raw sugar-making process, and raw sugar specifications.

What is Raw Sugar:

Raw Sugar is produced from sugar cane or beet by an ordinary process known as the Defecation process.  According to Peter Rein, raw sugar can be defined as  “Brown sugar produced in a raw sugar mill generally destined for further processing to refined sugar”.

a) It is Unwashed centrifugal sugar with minimum polarization 96.5^o .

b) Raw sugar surrounded by the original film of molasses, to be further refined or reprocessed for making it direct consumption sugar.

Flow Chart of Raw Sugar Process

The main steps in raw sugar making process:

Juice Extraction

The following technologies are using the extraction of juice from sugar cane or sugar beet

Milling Technology 

This process follows four or five stages (set of mills) for juice extraction in the milling process. According to that the set of mills in the system is called a 5-Milling Tandem or 4-Milling Tandem.

The milling tandem hot water is used for maximum extraction of juice from prepared cane. This hot water is also called imbibition water.

Mill sanitation

The first important operation in Raw sugar manufacture is “sanitation”. Every unit from mills to conveyors is kept clean to prevent bacterial infection. To control the growth of dextran good quality mill sanitation chemicals should be used in optimum doses. The growth of dextran should be controlled through proper sanitation.

For more information regarding the Milling Process please go through the below link

The concept in Milling Tandem in the sugar industry

Diffusion Technology

In the Diffusion process, sugar extraction from cane or sugar beet is actually affected by rupturing the cell of the prepared cane or beet cell and then washing the ruptured cells with hot water or low-concentrated juice obtained in the same process.Mills Vs Diffusers Technologies for Juice extraction systems in the sugar industry

Defecation Process

The process of Defecation is used in the clarification process of raw sugar and also in the Organic sugar manufacturing industry.

After extraction of the juice from sugar cane by milling or diffuser technology is subjected to a defecation process. This process can be defined as a neutralization of the raw juice by adding lime (add in the form of Milk of lime).

a) This is the oldest & cheapest method of juice clarification

b) In this process lime & heat are two basic agents.

c) The lime and heat treatment forms a heavy precipitate of complex composition.

d) Contains soluble lime salts, coagulated albumin, and varying proportion of the fats, waxes, and gums.

e) Phosphoric acid is added to increase P₂O₅ content of juice to 300 ppm.

f) Then lime is added to neutralize organic acids,

d) Besides insoluble tricalcium phosphate [Ca₃ (PO₄) _2­] is also formed which occludes colloids & suspended impurities.

For more information regarding the Defication process please go through the below link

Concepts of Juice Defecation Process in Raw Sugar Manufacturing Process

Settling

The limed juice or defecated juice or treated juice is heated up to 102⁰ C to 103⁰ C and then sent to a clarifier for settling & further filtration purposes.

The function of the juice clarifier is to separate insoluble solids in limed juice (Deficated juice), which are in “flocs” by means of settling and allowing the clear Juice.

The settling process separates the treated juices treated into two layers of clear juice which rises to the top surface and mud which collects at the bottom of the clarifier.

The different types of clarifier designs carry out this separation as completely and rapidly as possible. Normally settling aid is added so as to maintain the juice free from suspended matter and turbidity.

The settled mud in the clarifier contains also sugar so it will be extracted by using vacuum filters or decanters technology. The extracted juice in vacuum filters is again sent back to the defecation process.

Evaporation

The clarified juice is sent to evaporator bodies to increase its solid concentration. After evaporation, it is called syrup.

In the process of evaporation, the concentration of clear juice is carried out until the percentage of solids has reached 60%  to 70% as per the requirement. This evaporation process is conducted under a system of multiple-effect evaporators as per the view of energy conservation.

Robert Evaporator Design

Crystallization

The concentrated juice means the syrup is subjected to a process of crystallization. The crystallization process consists of the concentration of syrup and the formation of sugar crystals. This process is done by vacuum pans.

Straight there massecuite boiling scheme is followed for raw sugar making has to be taken to ensure uniformity and proper size of sugar grains. The raw sugar crystals are surrendered by a thin film of molasses and thus have a brownish appearance. 

The massecuite produced from vacuum pans is dropped to a cylindrical or ‘U’ shaped vessel equipped with a slow-speed stirring element which is called a crystalliser.

Centrifuging and Drying

The massecuite from crystallizers is taken into centrifugal to for the separation of sugar crystals and molasses. The centrifugal machine in which crystals in the massecuite are separated by using centrifugal force from the surrounding molasses or syrup.

In raw sugar production, use a little bit of washing of ” A massecuite” sugar in the Centrifugal and it is to be followed as per the output raw sugar colour requirement.  After centrifuging, the raw sugar dying flowed by cooling on a hopper by blowing hot and cold air. Bagging temp should be maintained near room temperature to prevent caking of raw sugar. The raw sugar should be quickly moved to the refined sugar process as far as possible or otherwise be stored in humid proof godown.

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