Page 20 - Plant design and economics for chemical engineers

INTRODUCI-ION 3

result of an orderly research program or an offshoot of such a program. The
operating division of the company may develop a new or modified chemical,
generally as an intermediate in the final product. The engineering department
of the company may originate a new process or modify an existing process to
create new products. In all these possibilities, if the initial analysis indicates that
the idea may have possibilities of developing into a worthwhile project, a
preliminary research or investigation program is initiated. Here, a general
survey of the possibilities for a successful process is made considering the
physical and chemical operations involved as well as the economic aspects. Next
comes the process-research phase including preliminary market surveys, labora-
tory-scale experiments, and production of research samples of the final product.
When the potentialities of the process are fairly well established, the project is
ready for the development phase. At this point, a pilot plant or a commercial-
development plant may be constructed. A pilot plant is a small-scale replica of
the full-scale final plant, while a commercial-development plant is usually made
from odd pieces of equipment which are already available and is not meant to
duplicate the exact setup to be used in the full-scale plant.
Design data and other process information are obtained during the
development stage. This information is used as the basis for carrying out the
additional phases of the design project. A complete market analysis is made,
and samples of the final product are sent to prospective customers to determine
if the product is satisfactory and if there is a reasonable sales potential.
Capital-cost estimates for the proposed plant are made. Probable returns on the
required investment are determined, and a complete cost-and-profit analysis of
the process is developed.
Before the final process design starts, company management normally
becomes involved to decide if significant capital funds will be committed to the
project. It is at this point that the engineers’ preliminary design work along with
the oral and written reports which are presented become particularly important
because they will provide the primary basis on which management will decide if
further funds should be provided for the project. When management has made
a firm decision to proceed with provision of significant capital funds for a
project, the engineering then involved in further work on the project is known
as capitalized engineering while that which has gone on before while the
consideration of the project was in the development stage is often referred to as
expensed engineering. This distinction is used for tax purposes to allow capital-
ized engineering costs to be amortized over a period of several years.
If the economic picture is still satisfactory, the final process-design phase
is ready to begin. All the design details are worked out in this phase including
controls, services; piping layouts, firm price quotations, specifications and de-
signs for individual pieces of equipment, and all the other design information
necessary for the construction of the final plant. A complete construction design
is then made with elevation drawings, plant-layout arrangements, and other
information required for the actual construction of the plant. The final stage * _
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