Code of Technical Standards for the Professional Practice of Chemical Engineering in the Sugar Refining Process and Operations

August 13, 2014

PRC BOARD OF CHEMICAL ENGINEERING RESOLUTION NO. 004(A)-14

ADOPTION AND PROMULGATION OF THE CODE OF TECHNICAL STANDARDS FOR THE PROFESSIONAL PRACTICE OF CHEMICAL ENGINEERING IN THE SUGAR REFINING PROCESS AND OPERATIONS

WHEREAS, Section 6 (f) of Republic Act No. 9297, otherwise known as the Chemical Engineering Law of 2004, empowers the Professional Regulatory Board of Chemical Engineering (Board) to inquire into the conditions affecting the practice of the profession and to adopt such measures for the enhancement and maintenance of high professional, ethical and technical standards;

WHEREAS, Section 6 (i) of the same law mandates the Board to adopt a Code of Technical Standards for the practice of chemical engineering;

WHEREAS, the unit processes and operations in sugar refining involve the application of chemical engineering principles and concepts in which the services of chemical engineers are indispensable;

WHEREAS, there is a need to prescribe a Code of Technical Standards for the practice of chemical engineering in the sugar refining processes and operations to ensure the competent and effective provision of professional services of chemical engineers in this industry;

WHEREAS, in the development and finalization of this Code of Technical Standards, the Board has consulted the stakeholders of the Philippine sugar industry such as, but not limited to, the Philippine Sugar Technologists Association, Inc. (Philsutech), Philippine Sugar Millers Association, Inc., (PSMAI), Philippine Sugar Research Institute (Philsurin), and the Philippine Institute of Chemical Engineers (PIChE), its Accredited Professional Organization (APO). cDHAES

WHEREAS, violation of any provision of this Code of Technical Standards shall give rise to liabilities under R.A. No. 9297 and other pertinent laws, policies, rules and regulations.

NOW, THEREFORE, the Board RESOLVES, as it is hereby RESOLVED, to adopt and promulgate, with the approval of the Commission, the Code of Technical Standards for the Professional Practice of Chemical Engineering in the Sugar Refining Processes and Operations, which is hereby made an integral part of this Resolution as Annex A.

This Resolution and Annex A, entitled, "Code of Technical Standards for the Professional Practice of Chemical Engineering in the Sugar Refining Processes and Operations", shall take effect after fifteen (15) days following its full and complete publication in the Official Gazette or in any newspaper of general circulation in the Philippines.

Let copies of this Resolution and its annex be transmitted to the UP Law Center, Philippine Sugar Technologists Association, Inc. (Philsutech), Philippine Sugar Millers Association, Inc., (PSMAI), Philippine Sugar Research Institute (Philsurin), and the Philippine Institute of Chemical Engineers (PIChE) for dissemination to all concerned.

DONE in the City of Manila this 13th day of August, 2014.

(SGD.) OFELIA V. BULAONGChairman

(SGD.) FRANCISCO A. ARELLANOMember

(SGD.) JEFFREY G. MIJARESMember

ATTESTED BY:

(SGD.) ATTY. LOVELIKA T. BAUTISTAOfficer-in-Charge

APPROVED:

TERESITA R. MANZALAChairperson

(SGD.) JENNIFER JARDIN-MANALILICommissioner

(SGD.) ANGELINE T. CHUA CHIACOCommissioner

ANNEX A

Philippine Chemical Engineering Standard-PChES 902:2011

PChES 902:2011 Code of Technical Standards for the Practice of Chemical Engineering: Sugar Refining

Scope

This Philippine Chemical Engineering Standard (PChES) establishes guiding principle for the development and use of code of technical standards for the practice of chemical engineering in sugar refining. It is intended that other applicable standards in the PChES series shall be used in conjunction with this Philippine Chemical Engineering Standard.

This Philippine Chemical Engineering Standard is intended for use as a specification for certification and registration purposes. SaHcAC

1 Normative References

The following referenced documents are indispensable to the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

Republic Act No. 9297, An Act Regulating the Practice of Chemical engineering and Repealing for this Purpose Republic Act Numbered Three Hundred and Eighteen (R.A. No. 318), otherwise known as "The Chemical Engineering Law".

Professional Regulation Commission, Board of Chemical Engineering Resolution No. 13, Series of 2004, The Implementing Rules and Regulations (IRR) of Republic Act No. 9297, an Act Regulating the Practice of Chemical Engineering and Repealing for this Purpose Republic Act Numbered Three Hundred Eighteen (R.A. No. 318), Otherwise Known as "The Chemical Engineering Law" Philippine Chemical Engineering Standards 1:2011.

2 Definition of Terms

For purposes of this document, the following terms and definitions shall apply.

Massecuite — the mixture of sugar crystals and mother liquor after crystallization

Raw sugar — a light brown to dark brown crystalline powder derived from processed sugar cane

Refined sugar — dried crystalline powder that is derived from raw sugar by imploring unit operations and unit processes

Sugar refining — the collection of unit processes and unit operations implemented in sequence to produce refined sugar

2.1 Specific Unit Operations

Affination — the treatment of raw sugar with a heavy liquid to remove the film of mother liquor coating the sugar crystals

Centrifugation — processing the massecuite in a machine which spins at high speed to cause liquid from the massecuite to run off

Clarification — the process of removing the turbidity of the sugar solution often with accompanying removal of color and often intentionally introducing turbidity as an early step

Crystallization — the process of having sugar crystals form and grow form a heavy sugar solution

Decolorization — the process of removing color from a liquid

Drying — removal of moisture from any material AaCEDS

Filtration — the process of having a liquid pass through a medium which retains certain undissolved solids

Melting — the dissolution of affined sugar usually with hot water or sweet water with the aid of agitation and heat

Packaging — putting a product in the desired container

2.2 Specified Unit Processes

Carbonatation — the proceeds of removing further impurities that precipitate from sugar solution with the reaction of carbon dioxide and calcium carbonate

Clarification — the chemical process of separating impurities from the sugar solution

Phospatation — the process of precipitating insoluble calcium phosphates of variable composition in hot melt liquor by first adding phosphoric acid, or an acid phosphate, followed by calcium hydroxide, either as slurry with water (milk of lime) or dissolved in sugar syrup as lime sucrate

2.3 Allied Profession

The following are the Allied Professions which will be involved in the Sugar Refining process:

Mechanical Engineer — Maintenance of mechanical components such as, but not limited to, pumps, conveyors and stirrers

Electrical Engineers/Electricians — Maintenance of electrical components such as, but not limited to, pump motors and electrical installations

Chemist — Sampling and analyses of Sugar Refining process materials

3 Sugar Refining Processes and Operations

3.1 Description of processes in Sugar Refining

Figure 4.1 presents the process flow diagram for sugar refining.

3.1.1 Affination

The Raw sugar massecuite is purged in a batch or continuous centrifugal baskets. This is to separate the raw sugar crystals from the molasses. In this state, the adhering molasses film loosens from the crystals and makes the further separation processes manageable. A % Pol 98.5 is to be obtained in this procedure. The Raw sugar color is greatly reduced from a range of 5000-8000 ICU to 1000-1800 ICU. This is due to the removal of the molasses film of raw sugar massecuite that coats the sugar crystals.

3.1.2 Melting

The affined sugar then undergoes melting to convert it to liquid form. The affined sugar is mixed with hot water (80-90 degree Celsius) or sweet water (40-50 degree Celsius). The dissolved form is termed as the untreated liquor. Brix of the untreated liquor is maintained at 60-65 degree Bx.

3.1.3 Clarification

The main objectives of the clarification process are to separate the impurities from the untreated liquor which will result to a reduction of color of the untreated liquor to 50%-70% and correct the pH of the untreated liquor and maintaining it to a 6.8-7.2 range. Clarification of untreated liquor can be carried out in two chemical process, carbonatation or phosphatation.

3.1.3.1  Carbonatation

The process consists of adding a slurry of calcium hydroxide in water to the untreated liquor. Then carbon dioxide gas is bubbled into the sugar solution in saturators, under controlled conditions of pH and temperature. Generally the carbon dioxide is added to the saturators in two stages, with the major part of the gassing carried out in the first saturator. The impurities are both absorbed by, and enmeshed in, the conglomerated particles of the calcium carbonate precipitated by the reaction of the carbon dioxide and calcium hydroxide. The optimum lime dose varies from below 0.4% CaO on solids in some liquors to over 1.2% CaO in others. IAEcCa

3.1.3.2  Phosphatation

The process consists of precipitating insoluble calcium phosphates of variable composition in untreated liquor by first adding phosphoric acid, or an acid phosphate, followed by calcium hydroxide, either as slurry with water (milk of lime) or dissolved in sugar syrup as lime sucrate, to give a final pH of 6.8-7.2. This treatment produces a calcium phosphate floc that is filtered with difficulty. Consequently, air flotation is commonly used to separate the precipitated solids from the liquor; such systems are called frothing clarifiers. During the flocculation and in the course of rising through the liquor, the floccules collect most of the fine suspended impurities in the solution. Impurities such as gums, waxes, and fines are swept from the liquor and appear at the surface as scum. In this manner a rather complete separation of the precipitate and impurities is obtained without resorting to settling or filtration. The scum are then removed from the liquor surface by a skimming device. 

3.1.4 Filtration

After the untreated liquor is clarified, it now becomes clear golden-brown colored liquid termed as clarified liquor. The clarified liquor is passed into a filter. For clarified liquor which is produced from carbonatation process, it is filtered through a filter press to remove the calcium carbonate precipitates that are carried out in the clarified liquor. For clarified liquor that is produced from the phosphatation process, a multi-media filter is used wherein adhering scum is removed. Color, Brix, and pH are maintained in this process and the product now becomes filtered liquor.

3.1.5 Decolorization

The filtered liquor is then decolorized using ion exchange resin. The filtered liquor is made into contact with the ion exchange resin in a closed vessel wherein cationic and anionic reaction takes place. A reduction of 90% in color is achieved in this process. The filtered liquor now becomes golden-yellow in color and becomes decolorized liquor. Brix and pH are maintained at 60-65ºBx and 6.8-7.2 respectively.

3.1.6 Crystallization

Crystallization of sugar is then done using the decolorized liquor. This is done by increasing the concentration of the decolorized liquor from 60-65º Bx to 68-70º Bx, which is the point where crystals grow. Optionally, the decolorized liquor may undergo evaporation before crystallization to increase the concentration. Crystallization process may take 1.5-2 hours to complete which produces a sugar crystal mixture called massecuite which has Brix of 88-90ºBx. ADaSET

3.1.7 Centrifugation

The massecuite is then introduced into centrifugal machines to separate the crystals from the mother liquor or molasses. The separation can be carried out batch or continuous operations. The products of this process are refined sugar crystals, which go to the Dryers, and molasses, which go back to the crystallization process.

3.1.8 Drying

The refined sugar crystals are passed on to the Dryer to reduce the moisture. This is done by having the refined sugar crystals come in contact with relatively dry air to attain the moisture of 0.02. Lowering the moisture provides ease in storage.

3.1.9 Packaging

The dried refine sugar is then packaged. Usual packaging is in bags of 50 kilos referred to as Lkg bags. The bags lined with plastic to protect the refined sugar from moisture and caking.

4 Practice of Chemical Engineering in Sugar Refining

4.1 General requirements

Sugar refining processes and operations shall require the services of a chemical engineer.

A chemical engineer shall ensure that the sugar accepted to the sugar refinery is either fit for human consumption or will be made fit for human consumption by the refinery.

A chemical engineer shall ensure that nothing added to or made to come in contact with the sugar shall render it unfit for human consumption.

A chemical engineer shall ensure that the environmental impacts of the sugar refining activity are taken care of.

4.2 Practice of chemical engineering in sugar refining

The following processes and operations in sugar refining shall require the services of a chemical engineer:

Affination

Melting

Clarification

Filtration IDESTH

Decolorization

Crystallization

Drying

The following processes and operations in sugar refining may require the services of a chemical engineer:

Centrifugation

Packaging

5 Certificate of Compliance of Sugar Refineries

All sugar refineries, as defined as industrial plants in R.A. No. 9297, requiring the professional services enumerated in Section 4.2 of PChES 1:2011 for the processes and operations listed in Section 5.2 of this Standard must avail of the services of a chemical engineer. The Board shall issue a Certificate of Compliance to industrial plants that have complied with the provisions of R.A. No. 9297.

6 Act Not Affecting Other Professions

The Code shall not be construed to affect or prevent the practice of any lawfully recognized profession.

Published in the Official Gazette, Vol. 110, No. 50, Page 7651 on December 15, 2014.