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23-Chem-A5 Chemical Plant Design and Economics · May 2017

Question 6 of 6: Factors in Chemical-Plant Site Location

Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)

Notes on this paper

Closed-book exam, 3 hours; one aid sheet permitted. Six questions of equal value (20 marks each); five constitute a complete paper — full solutions to all six are given here. Questions 1 and 2 are quantitative (plant material balance and discounted-cash-flow return); Questions 3–6 are design-practice list/essay questions.

Reference texts: M.S. Peters, K.D. Timmerhaus & R.E. West, Plant Design and Economics for Chemical Engineers (5th ed., McGraw-Hill) — the exam's named primary text (process design development Ch. 2, general design considerations: plant location, safety, materials Ch. 3, interest and profitability Ch. 7–10, materials-transfer/pumps Ch. 14); R.H. Perry & D.W. Green, Perry's Chemical Engineers' Handbook (9th ed.) — pump types and selection (Sec. 10), pyrolysis kinetics data; O. Levenspiel, Chemical Reaction Engineering (3rd ed.) — first-order plug-flow space-time behind the reactor sizing in Question 1; supporting Canadian practice from CCOHS and the CSA Z767 / provincial OH&S process-safety-management framework for Question 5.

Question 6: Factors in Chemical-Plant Site Location (20 marks)

Question text not reproduced: the examination questions are © Engineers and Geoscientists BC. Open the official past paper (linked at the top of this page) to read the question, then follow the worked solution below.

Given / Find. A plant-location question. The answer separates the broad regional (primary) factors from the site-specific factors, each briefly described, following the Peters & Timmerhaus treatment.

(a) Five primary factors (choice of region)

  1. Raw-material availability — proximity to feed sources reduces transport cost and supply risk; often the dominant factor.
  2. Markets / product distribution — nearness to customers lowers shipping cost and improves service, especially for bulky or hazardous products.
  3. Energy / utilities availability — reliable, low-cost power, fuel, and steam; access to cooling and process water.
  4. Climate — temperature extremes, humidity, wind, and snow affect construction, heating/cooling loads, and outdoor operation.
  5. Transportation facilities — road, rail, water (port), and pipeline access for feeds, products, and construction.

(b) Ten specific factors (exact site within the region)

  1. Water supply — quantity, quality, temperature, and reliability of process and cooling water.
  2. Effluent/waste disposal — capacity of receiving water/land and compliance with discharge limits.
  3. Labour supply — availability, skill level, wage rates, and industrial-relations climate.
  4. Local taxation and legal restrictions — property/business taxes, zoning, and by-laws.
  5. Site characteristics — land cost, soil bearing/foundation conditions, topography, and drainage.
  6. Flood, drainage, and seismic risk — elevation above flood level and earthquake exposure.
  7. Room for expansion — adequate adjacent land for future capacity.
  8. Community factors — housing, schools, services, and public acceptance/attitude toward the plant.
  9. Environmental and regulatory constraints — air-quality zoning, protected areas, permits.
  10. Fire protection and safety services / utility connections — access to municipal fire, emergency, and utility tie-ins.

In practice the primary factors are weighted and scored to shortlist two or three candidate regions, after which the specific factors are costed in detail for competing sites within each region. Because the location is fixed for the plant's operating life, the objective is to minimise the total of capital plus recurring delivered-and-operating cost, not simply to find the cheapest land; a poor water supply or effluent-disposal situation, for example, imposes an operating penalty every year of the plant's life.

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