• Author / Uploaded
• Samiksha Rajdev

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Design Aspects

DESIGN BASIS Before a chemical process design can be properly embarked on, a certain body of information must be agreed upon by all concerned persons, in addition to the obvious what is to be made and what it is to be made from. Distinctions may be drawn between plant expansions and wholly independent ones, so-called grassroots types. The needed data can be classified into specific design data and basic design data, for which separate check lists will be described. Specific design data include:

1. Required products: their compositions, amounts, purities, toxicities, temperatures, pressures, and monetary values. 2. Available raw materials: their compositions, amounts, toxicities, temperatures, pressures, monetary values, and all pertinent physical properties unless they are standard and can be established from correlations. This information about properties applies also to products of item 1. 3. Daily and seasonal variations of any data of items 1 and 2 and subsequent items of these lists.

4. All available laboratory and pilot plant data on

reaction and phase equilibrium behaviors, catalyst degradation, and life and corrosion of

equipment. 5. Any available existing plant data of similar

processes. 6. Local restrictions on means of disposal of

wastes.

Basic engineering data include:

7. Characteristics and values of gaseous and liquid fuels that are to be used.

8. Characteristics of raw makeup and cooling tower waters, temperatures, maximum allowable temperature, flow rates

available, and unit costs. 9. Steam and condensate: mean pressures and temperatures and

their fluctuations at each level, amount available, extent of recovery of condensate, and unit costs.

10.

Electrical

power:

Voltages

allowed

for

instruments, lighting and various driver sizes, transformer capacities, need for emergency generator, unit costs.

11. Compressed air: capacities and pressures of plant and instrument air, instrument air dryer. 12. Plant site elevation.

l3. Soil bearing value, frost depth, ground water depth, piling requirements, available soil test data. 14. Climatic data. Winter and summer temperature extreme, cooling tower dry-bulb temperature, air cooler design temperature, strength and direction of prevailing winds, rain and snowfall maxima in 1 hr and in 12 hr, earthquake provision. 15. Blow-down and flare: What may or may not be vented to the atmosphere or to ponds or to natural waters, nature of required liquid, and vapor relief systems.

16. Drainage and sewers: rainwater, oil, sanitary. 17. Buildings: process, pump, control instruments, special 18. Paving types required in different areas.

19. Pipe racks: elevations, grouping, coding. 20. Battery limit pressures and temperatures of individual feed stocks and products.

21. Codes: those governing pressure vessels, other equipment, buildings, electrical, safety, sanitation, and others. 22. Miscellaneous: includes heater stacks, winterizing, insulation, steam or electrical tracing of lines, heat exchanger tubing size standardization, instrument locations.