Sugar Refinery Terminology

Sugar Final product of Sugar Refinery. Chemically, a form of Disaccharides or Carbohydrates, essentially sucrose.

Raw sugar is produced in a raw sugar plant and requires further processing in a refinery. Raw sugar is the raw material for sugar refineries. Some raw sugar mills have refineries attached to them. And there are standalone refineries that purchase raw sugar from raw sugar mills and refine it in their process house.

Sucrose β-D- Fructofuranosyl α –D- glucopyranoside is the chemical name of sucrose, which is pure chemical compound of formula C2H22O11, widely known as sugar. 

Source: Wikipedia

Ash Content A quantitative measurement of Solid residue from incineration in oxygen presence. High ash content in Raw Sugar will require much more filtration and have a negative impact on total sugar refining capability. Ash content in sugar products is determined by incinerating a sample in the presence of oxygen and measuring the solid residue gravimetrically. During the analysis, sulfuric acid is added to the sample and the resulting sulfated ash is heated to 525°C to measure the inorganic constituents. Ash content can also be determined directly by measuring the electrical conductivity of the product solution. Higher ash content in raw sugar foretells more granular adsorbent (such as Ion Exchange Resin) for clarification and can reduce the capacity of a refinery.

Brix(°Bx) Generally, an estimation of dissolved solids in Sugar or Liquor. A refractometer is used to measure Brix. In Sugar Refineries, Brix simply refers to percentage (%) sugar by mass in a sugar-water solution. So, 1°Bx means 1gm dissolved in 100gm solution. As Raw Sugar contains impurities other than sucrose, solution made from it represents approximate dissolved contents.

Polarization (Pol) Polarization, or Pol, refers to the measurement of the apparent sucrose content in a sugar solution. It is expressed as a mass percent and is determined by measuring the optical rotation of polarized light passing through the solution. This method is only accurate for pure sucrose solutions.

Purity indicates the percentage of sucrose content in the dry substance or dissolved solids content. The solid contents refer to sugar and non-sucrose components such as invert, ash, and colorants. Purity is measured by dividing the polarization by the Brix and multiplying by 100.

Purity =(Pol/Brix)*100 %

ICUMSA (IU) The color of sugar is an important factor for determining its quality and market value. The color level of a sugar sample, expressed in International Units (IU), can be determined by measuring the absorbance of the sugar solution at a wavelength of 420nm. Before the measurement is taken, the sugar solution must be filtered and pretreated using filter paper with a pore size of 0.45 um. ICUMSA stands for International Commission for Uniform Methods of Sugar Analysis.

Invert sugar is a mixture of glucose and fructose in approximately equal parts. It is produced by inversion which is hydrolysis of sucrose.

Reducing sugars are often referred to as invert sugar. Laboratory analysis is performed to measure reducing substance in sugar. 

Dextran is a water-soluble polysaccharide of glucose derived under a certain type of lactic acid bacteria associated with fermentation under conditions like salinity and low temperature. The bacteria are called Leuconostoc Mesenteroides which is well adapted to sugary environments and has a variety of biocatalytic modification capabilities. Dextran has a molecular weight varying from 2000 to 20000. It is derived from a long polymer chain of glucose molecules attached together by alpha 1:6 linkages. Dextran can be present in harvested cane or form during transportation or storage in the long run. The presence of a high percentage of dextran in raw sugar can increase the viscosity of the syrup and affect both production capacity and cost due to poor filtration capability, crystallization rate, clarification, and pan boiling rate.

Starch is a polysaccharide formed when many sugar molecules are attached together in a long chain. In case of the number of sugar molecules in stach chain, its basic chemical formula is (C6H10O5)n. The presence of high percentage of starch in raw sugar has disadvantageous effect on the process as it directly affects the filtration capability and eventually decreases the production capacity.

Moisture Content/Safety Factor A small amount of water may reduce the protective film of molasses around the crystal to a dangerously low density, permitting micro-organisms to penetrate sugar crystals themselves and start deterioration. Sugar refining industries use water content to non-sugar content ratio to calculate the safety factors. It is of great importance that raw sugar, which is to be stored even for a relatively short period of time, has a safety factor 0.25 or less.

SF= (W*100)/ NS = (W*100)/ (100-(S+W))

Where W is water, NS is non-sucrose and S is sucrose

Melter is where Raw Sugar is dissolved for processing. It is also called Melting in Sugar Refinery. Raw Liquor syrup is created by dissolving or remelting centrifuged low-grade sugar. This raw liquor is then sent to the next phase for clarification.

Calandria is a heat exchanger used to heat up liquor in Carbonator, Evaporator and Pan. It can either be shell and tube type or plate type.

Carbonator is the clarification processing unit where Carbonation takes place in presence of CO2 gas and Milk of Lime (suspended lime solution).

Carbonation is a clarification process involving Milk of lime and CO2 to form Calcium Carbonate (CaCO3), which removes colorants and non-sucrose elements from liquor.

Crystallization is the process of forming solid crystals from a solution. It involves two main stages: nucleation and growth. Nucleation is the initial formation of small crystals, while growth refers to the increase in size of these crystals.

Sweet water refers to water that has been used to wash something or contains a small amount of sugar. Generally, sweet water is stored in a tank from washed water from filtration section, IER washing, Filter Press water.

Nucleation is the process of generating and developing small crystals that are capable of growing. It is the first stage of crystallization and is essential for the formation of solid crystals from a syrup solution.

Strike refers to the completed boiling of massecuite, which is a mixture of sugar crystals and mother liquor. After boiling is complete, the entire contents of the pan are discharged.

Seed refers to either a suspension of fine crystals in a saturated alcohol solution or the initial grain that results from seeding in a vacuum pan.

Seeding is the process of introducing crystal fragments to induce nucleation and initiate the crystallization process. It may also refer to the process of introducing fine crystals in the form of a slurry to initiate crystallization. Sometimes it is called Graining.

Massecuite is formed from the crystallization process during pan boiling and is a mixture of sugar crystals and mother liquor. Generally, a pan strike consists of 50% massecuite and 50% molasses. Reduced massecuite percentage indicates lower refined sugar from a strike.

Molasses is the separated segment of massecuite after centrifuging. There can be different grades of molasses from different massecuites. R1, R2, R3, R4, A, B, C are different grades of sugar based on their IU color. From R1 massecuite curing we get R1 sugar and molasses. R1 molasses are then used to boil R2. This process is repeated all the way till C molasses.  A, B and C sugar are boiled in the recovery section. C molasses are generally called Final Molasses.