Chemical process Economics :-
Engineers are distinguished from scientists by their consciousness of costs and profits.Every
engineering decision involved cost consideration. Engineers must continue to
keep abreast of Economic changes that may affect their products.The primary objective
of the engineers endeavors should be to deliver safely the best product or the
most efficient service at the lowest cost to the employer and the consuming public.
Competing process:-
Since change is an
outstanding characteristic of the chemical procedures, potential alteration of
any process is of importance not only when the plant is first designed, but continuously.
One of the functions of a research and devolpment (R&D) division is to keep
abreast of progress and to make available knowledge of improvements or even
fundamental changes leading to the making of any given product in which the
organization is interested. This R&D component must keep informed regarding
devolpmemts in other companies and be in a position to advise management of the
relative competitive positions of actual or anticipated proceses or products.
judgement based on comparative facts must be exerted in most of the important discussions
of the chemical engineer.For instance, there are many technical processes for making
phenol, ethanol, and acetic acid. Choosing the one from among many that is best
for a particular location or time is an economic decision.Careful calculations
using local parameters generally yields a clear decision.
Material balance:-
Yields and conversions of the chemical process from the
basis for the material balance, which in turn are the foundation for cost determination.
When obtainable, materials and quantities from standard practice are tabulated under
the flow charts.
Energy
Engineers are concerned with the direction and control of energy.This
energy may be expended in the moving of raw materials by ships, trucks or pipeline;
it may be employed in the form of heat of steam or elcetrcity; or it may be energy
the energy given out in exothermic reactions, or that which is absorbed in endothermic
chemical reactions.Enegy costs from oil,gas,coal,solar,nuclear,or electrical
energy from air or water power are all constantly changing, so it is extremely
difficult to make long range plans.Energy is frequently major cost in chemical
plants, but it is often possible to reduce energy use by altering processing
procedures, particularly by using new separation technologies.
Chemical Processing
Labor:-
Skilled operators contribute as much to a plant's success as
excellence in design. Without their cooperation, no plant succeeds.The chemical
process industries have moved rapidly into labor saving techniques:
particularly, rapid extension of continous processing, the use of process
controllers, and optimizing procedures. Labor requirements in the chemical industry
are comparatively small, but many jobs require above average skills and pay
above average wages
Overall cost:-
The cost of
processing cannot be finally obtained until the plant is in operation, but an
experienced chemical engineer can closely estimate it. The single largest cost
is usually raw material,with energy, labor, overhead, and depreciation all
being significant.Most errors in cost estimation are due to an underestimate of
overhead, sales, customer service, and the cost of capital required to finance
the daily operation of the business.After the plant has been designed, bids can
be obtained for the equipment, which will indicate the amount of the capital necessary
for construction. With high interest rates and constantly rising costs, delays can
be extremely expensive. Taxes may also prove to be a major factor.Table presents
capital spending for new plants.
Table 2.1 Chemical industries(Chemical Processing) Capital Spending for New Plants (in billions of dollars )
|
|
1981
|
1980
|
1978
|
1976
|
1974
|
1972
|
|
Chemical and allied products
|
13.11
|
12.60
|
8.46
|
8.12
|
6.48
|
3.38
|
|
Iron and steel
|
3.27
|
3.29
|
2.52
|
3.04
|
1.94
|
1.06
|
|
Non-ferrous metals
|
3.59
|
3.11
|
2.11
|
1.97
|
2.04
|
0.97
|
|
Paper
|
6.73
|
6.80
|
3.99
|
3.1
|
2.90
|
1.45
|
|
Petroleum
|
25.17
|
20.69
|
13.95
|
10.76
|
7.31
|
4.80
|
|
Rubber
|
2.30
|
1.73
|
2.10
|
1.32
|
1.56
|
1.03
|
|
Stone, clay, glass
|
3.90
|
3.82
|
3.10
|
1.88
|
1.64
|
1.33
|
|
All manufacturing
|
129.85
|
115.81
|
79.72
|
59.95
|
53.21
|
35.42
|
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