Process: Process as used in
the terms process control and process industry, refers to the methods of
changing or refining raw materials to create end products. The raw materials,
which either pass through or remain in a liquid, gaseous, or slurry (a mix of
solids and liquids) state during the process, are transferred, measured, mixed,
heated or cooled, filtered, stored, or handled in some other way to produce the
end product. Process industries include the chemical industry, the oil and gas
industry, the food and beverage industry, the pharmaceutical industry, the
water treatment industry, and the power industry.
Process
control:
Process control refers to the methods that are used to control process
variables when manufacturing a product. For example, factors such as the
proportion of one ingredient to another, the temperature of the materials, how
well the ingredients are mixed, and the pressure under which the materials are
held can significantly impact the quality of an end product. Manufacturers
control the production process for three reasons:
1. Reduce variability
2. Increase efficiency
3. Ensure safety
4.
Reduce variability
Process control can
reduce variability in the end product, which ensures a consistently
high-quality product. Manufacturers can also save money by reducing
variability. For example, in a gasoline blending process, as many as 12 or more
different components may be blended to make a specific grade of gasoline. If
the refinery does not have precise control over the flow of the separate
components, the gasoline may get too much of the high-octane components. As a
result, customers would receive a higher grade and more expensive gasoline than
they paid for, and the refinery would lose money. The opposite situation would
be customers receiving a lower grade at a higher price.
Reducing variability
can also save money by reducing the need for product padding to meet required
product specifications. Padding refers to the process of making a product of
higher-quality than it needs to be to meet specifications. When there is
variability in the end product (i.e., when process control is poor),
manufacturers are forced to pad the product to ensure that specifications are
met, which adds to the cost. With accurate, dependable process control, the set
point (desired or optimal point) can be moved closer to the actual product
specification and thus save the manufacturer money.
2. Increase
efficiency
Some processes need to
be maintained at a specific point to maximize efficiency. For example, a
control point might be the temperature at which a chemical reaction takes
place. Accurate control of temperature ensures process efficiency.
Manufacturers save money by minimizing the resources required to produce the
end product.
3. Ensure
Safety
A run-away process,
such as an out-of-control nuclear or chemical reaction, may result if
manufacturers do not maintain precise control of all of the processg variables.
The consequences of a run-away process can be catastrophic.
Precise process control
may also be required to ensure safety. For example, maintaining proper boiler
pressure by controlling the inflow of air used in combustion and the outflow of
exhaust gases is crucial in preventing boiler implosions that can clearly
threaten the safety of workers.
No comments:
Post a Comment