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Feasibility Phase

During the initial phase, AVEC will establish current constraints such as product quality, currentmarket demand, existing refinery capacity and existing refinery condition. Typically, this type of 

investigation includes physical on site examination of equipment as well as a review of 

inspection and other records. A process simulation will be performed to obtain a model for use infurther design and to establish the operating constraints.

Existing legislation and product standards, locally and internationally, will be reviewed toestablish likely future product requirements. Market research based on current economic

conditions and expected future conditions, will be used to predict demand. This research is oftendone using the expertise of consultants with appropriate local experience.

This phase could take 4 to 6 weeks, depending on the complexity of the system. Throughout the period, AVEC will work in close consultation with the client, providing regular feedback on

 progress.

Conceptual Phase

The predicted future demand is used to establish various revamp scenarios. Using the simulationand existing equipment data, the extent of revamp required to reach different demand cases is

determined. Using conceptual estimating techniques, an order-of-magnitude cost estimate for thedifferent scenarios is obtained. The emphasis for this type of cost estimate is on establishing the

differences between different options.

The cost estimates for different demands are compared with revenue generated and the

information is used to plan a revamp process to meet demand for the required period into the

future.

At this stage, a formal value engineering exercise is carried out to establish where opportunity

exists for increasing value. Typically, a number of alternate designs or options are generated, the best of which are investigated further. The optimum alternatives are then incorporated into the

design for further engineering. As the design progresses and more detail and firmer costs becomeavailable, it is often useful to perform another value engineering exercise.

The conceptual phase takes 6 to 8 weeks depending on the required estimating accuracy,

complexity of solutions/options and the number of scenarios to be estimated. Typically at the endof this phase the following are available:

y  Process flow diagrams, mass and energy balancesy  Equipment lists

y  Preliminary equipment sizingy  Order-of-magnitude cost estimates

y  Economic evaluation

Basic Engineering

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After the concept has been finalised and agreed with the refinery management, the design proceeds to firm up details. Process conditions are frozen and detailed equipment specifications

are produced. Input from mechanical, piping, control systems, electrical and civil engineeringdisciplines is included to complete the design. Experts are used from other organisations where

specialised skills are required. Detailed Piping and Instrumentation Diagrams (P&ID's) are

 produced showing the requirements of all disciplines. Equipment, instrumentation and materialspecifications are sent to suppliers to obtain quotations and details of required items. Global procurement is used to source material in the most effective manner, from both cost and schedule

considerations.

During this phase, which could last about 3 months, reviews are held with clients, suppliers andinternally to ensure the refinery's requirements are met and that the suppliers understand their 

requirements. Suppliers are often selected at this stage, although orders are not yet placed.

At the end of this phase a Hazard and O perability study (HAZOP) is held to ensure the design isworkable and safe. The cost estimate is updated with an improved accuracy, based on the

additional information.

Detailed Engineering and Construction

Once all the planning and analysis is complete, AVEC's engineering departments get into full

swing. Orders are placed for equipment, especially long delivery items. Any items not yet firmedup are defined and engineering completed. Any changes or updating are extremely tightly

controlled to prevent omissions, schedule threats or escalating costs. The duration of this phasenormally depends on equipment delivery. Careful planning is required to reconcile delivery

times and commissioning and start-up requirements. Material must arrive on site in time tofacilitate construction. Effort is concentrated on expediting and inspection to ensure that items

reach site on time and are correct.

Any delays during engineering can cause an impact on the construction team, who need theflexibility to respond appropriately. A key consideration during construction phase is the safety

of construction labour and other people in the vicinity of the site. At the end of construction thesite is normally handed back to the owner for commissioning and start-up.

Commissioning and Start-Up

During this final phase, AVEC begins the process of transferring the revamped refinery back tothe refinery owner. AVEC usually continues to provide some assistance during this phase and for 

some projects the plant is only handed back to the owner after it is on-line and operatingnormally. Depending on the kind of contract and what guarantees are involved, a design rate test

run is sometimes done once the plant is running.