Monday, August 1, 2011

Design and engineering stages of Alumina refinery

Hi Friends,


In present post, we will elaborate the various stages of design and engineering for successful execution of any Alumina refinery project. There are four stages of design and engineering as described in subsequent paragraphs-
1. Conceptual design: This is the initial stage of plant design wherein design basis is developed on the basis of estimated bauxite reserves, mineralogical composition of bauxite, availability of infrastructure, probable location of refinery, site information, meteorological data, technological options, process route, cost estimates and financial analysis are worked out to have the indicative figures on capex, opex, IRR and pay back period. This stage is also known as pre-feasibility / feasibility stage or Front-end loading-1/ Front-end loading-2 (FEL-1 / FEL-2) of the project. It is the pre-project planning stage of the project. At this stage, the accuracy in cost estimates is generally + 20% as equipment price data are generally based on norms of industry standard. This study gives fair idea of returns on investment for taking decision to go ahead further. Promoter driven organizations find this document adequate for their path forward, however, Public sector organization and Word bank funded projects require further studies / reports like DPR / FEED, as detailed below, to reaffirm the feasibility of the project with improved accuracy level of projected financial figures.
2. Preparation of basic design package : This is the next stage of plant design prepared on the basis of bauxite reserves, project site details and inputs received from process technology supplier. This document is also known as  Detailed project report (DPR) as it covers over 50% of engineering activities for execution of the plant. At this stage almost all technical figures are firmed up. This stage is also known as Front-end engineering and design (FEED) or Front-end loading-3 (FEL-3) by engineering consultants of different parts of the globe. FEED is the critical stage of the project for successful execution of Alumina refinery. FEED includes broad specifications of equipment and facilities for getting quotations. It gives clear understanding of key economic and risk factors of the Alumina refinery project. At this stage, the accuracy level in financial figures is +10% as it is developed based on detailed working backed by budgetary quotations from equipment suppliers.
3. Development of basic engineering: Since FEED document is prepared based on preliminary basic engineering data supplied by technology supplier, thus it becomes the basis for development of Basic engineering. At this stage, all process, design and engineering data are fine tuned, firmed up and finalized. Size and capacity of all equipment and facilities are worked out precisely with utmost accuracy on the basis of outcome of process simulation analysis. Design criteria, safety aspects and environmental management issues are addressed in detail with clarity. Each and every data covered in FEED document are checked, modified if required and frozen with utmost care and accuracy. Basic engineering document is the final design and engineering document for carrying out detailed engineering to initiate procurement activities. 
4. Detailed engineering: Design and engineering document developed during basic engineering stage is translated in detail incorporating required services, utilities and other aspects as earmarked in basic engineering document for completeness of specifications vis-a-vis tender document for procurement of equipment and facilities for setting up Alumina refinery. Working drawings are developed matching equipment dimensions and their locations in plant area. Preparation of design drawings and fabrication drawings for structural work is done at this stage only. Adequate working space is kept in mind for easy movement of man and machines  safely. Detailing of material handling system, power distribution, instrumentation and controls, fire fighting and facilities for pollution control are carried out at this stage of project for successful implementation.
Activities stated under serial number-2 and 3 are engineering (E) part and those described under serial number- 4 are procurement and construction (PC) part of so called Engineering, procurement and construction (EPC) methodology of project. Method of managing all three activities together is popularly known as Engineering, procurement and construction management (EPCM) of Alumina refinery project. We will discuss the list of activities covered under each stage of design and engineering of Alumina refinery in forthcoming posts.

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Kunwar Rajendra

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