Business: Industrial

Getting Ideas for Energy Management Opportunities
2.1 General foundry management

2.1.1
Building design and plant layout

The opportunity to design a foundry
and prepare an effective layout of the process and equipment is rare. It is
a complex subject, well beyond the scope of this guidebook. In trying to find
an ideal solution, many often-conflicting requirements would have to be reconciled.
For example, a new, "green" field-built foundry should:

• Utilize the space available
  in the building maximally;
• Facilitate a natural process flow, with easy access
  for in-plant transportation, operators and maintenance;
• Provide a healthy and
  environmentally sound workplace;
• Allow for future expansion of the plant so
  that it could merge organically with the existing operations;
• Minimize distances
  for transporting materials (e.g., scrap, returns, sand, moulds) and conveying
  molten metals;
• Allow for dry and ambient-temperature storage of raw materials,
  particularly scrap;
• Include a provision for utilization of all major opportunities
  for energy conservation, described elsewhere in this guidebook; and
• Have effective dust
  removal and ventilation systems, which use locally available sources of
  waste heat for winter heating.

From the energy point of view, the biggest planning
problem is to supply the furnaces with scrap and returns and to get the molten
metal to pouring as effectively as possible. Poor planning of these two essential
transport systems can effectively double energy costs!

Proper planning of localized
exhausts from dust and/or emissions-producing pieces of equipment can be done
after the design
stage of the production layout
rather than before. Otherwise, the result could be over-dimensioned foundry
ventilation, which wastes energy in excessive air change and heating the make-up air.

A new foundry facility should reach for a higher level of performance than
what is current, in every respect. The requirement to improve energy efficiency
should be built into the design and quantified. The quantification provides
a useful cross-check. The existing foundry can provide the specific energy
consumption, X, in MJ/kg of product (unit of product), against
which the projected specific energy consumption, Y, is compared.
The projected value would be a close estimate at this point, given the project’s
various development issues, and would be based on manufacturers’ data
for certain key pieces of equipment. The Y value should include
consideration of all the energy imported into the operations,
from which energy recuperated by the project’s new energy-conserving
features (such as hot water for general building heating, steam for a cogenerator)
has been subtracted. The new foundry’s energy efficiency is then expressed
as E (%) = [(X – Y) / X] × 100.

This approach, practised by some well-known,
major industrial companies, ensures that energy-saving features are built into
each new capital project, whether
it is buildings, a casting line or individual capital equipment purchases.

Each new project involves making compromises between what is desirable and
what is possible within the project restraints, such as budget, space, etc.
The energy efficiency of a project is one of the criteria that may be subjected
to these considerations. An explanation of a simple technique to use in judging
the effects of project trade-offs is described in Section 3.3, “Selecting
and prioritizing EMO projects” (page 92).

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