Objective 03: Design and Construction Flashcards
What are some of the items assessed in a Feasibility Study, in detail?
- Size of the Plant and its main process flows
- Demand for product, e.e. electrical power, oil and gas, or chemicals
- Influence of government regulations, e.g. environmental impacts
- Economic alternatives, e.g. different process designs or plant sizes
- Choices of plant processes, fuels, auxiliary equipment, degree of instrumentation and automatic control
- Mode of operation, i.e. whether plant is run in steady state mode, is base loaded, or used for peak loads
- Choice of cycle, e.g. is it simple or cogeneration
- Choice of fuel - cost and availability, handling costs, and fixed charges
- Amount of instrumentation and automatic control
What are some of the items included in the Detailed Design, in detail?
- Detailed drawing, e.g. P&IDs
- Detailed specifications for all engineering disciplines including material specifications
- Construction drawings, including isometric piping drawings
- Process flow diagrams with mass balances
What form may Drawings take?
- Paper-based
- Computer based on CAD programs
- Combination
- Scale model of the plant equipment
- 3D computer images of the equipment
What are the 2 basic steps in Plant Design?
- Feasibility Study
- Detailed Design
What are the 3 basic steps in Plant Construction?
- Construction Company or Primary or General Contractor selected through bidding process
- They oversee construction of the plant
- Once plant is constructed, equipment is started up (commissioned)
What are the steps of the Bidding/Negotiation Phase?
- Companies with expertise to construct plant are located.
- Short list of 1-6 of the most suitable companies is compiled
- A copy of the plant design is given to each of them
- Each company supplies bid based on plant design, that details the timeline, forms of payment, and other required details
- After bids are received, bid review process analyses the competing bids
- From analysis, the winning bid is selected (usually the lowest)
What is the role of the engineering staff during the construction phase?
- Contract administration, including resolving any design changes
- Quality assurance
What are some causes of design changes?
- Omissions from the original design
- Factors that don’t comply with the original design
- Request by the Plant Owner
What is the consequence of making design changes during construction?
- More significant changes add to the cost of the project as the changes must be re-engineered and changes made to the drawings and specifications
- Smaller field changes require little or no engineering changes
What is the basic order of the construction work?
- Site grading and roads
- Excavating for underground piping and foundations
- Laying underground piping and pouring cement foundations
- Work on the main electrical supply, including installation of the main substation and motor control centres
- Placing of major pieces of equipment on their foundations
- Installing steelwork for buildings and structures
- Erection of larger buildings and furnaces
- Placing of large pressure vessels and rotating machines on their foundations
- Installation of large diameter piping
- Installation of small diameter piping, including instrumentation and electrical wiring
- Installation of small pumps, motors, and turbines
- Insulation of piping and tanks
When does pre-commissioning begin?
Once piping is complete
What is Pre-Commissioning?
Activities that must be completed before commissioning or startup of the plant can begin.
What activities are included in pre-commissioning?
- Air or steam blowing and purging of piping to remove debris, scale, and liquids; often preceded by a chemical clean
- Checking the operation of control loops from the control room to field devices such as valves and dampers
- Hydrostatic testing and leak testing of flanges and piping
- Test running pumps and motors
What is Commissioning?
Process startup of a new plant
What is the general outline of commissioning?
It is done in systems, starting with the plant offsites and utilities and working through the process until the final product.
