(72z) Improving Process Sustainability and Profitability for a Large U.S. Gray Iron Foundry

Improving Process Sustainability and Profitability for a
Large U.S. Gray Iron Foundry

Prashant
Nagapurkar, Shyam Paudel and Joseph D. Smith, PhD.

Missouri
University of Science and Technology, Rolla, Missouri, USA

Abstract

Energy savings and sustainability
has been an important topic in many industrial processes.  Limited energy resources and increasing
electricity prices make foundry processes less competitive in today's world
economy.  For foundry processes, the
energy costs generally represent 5-7% of the total sales. Most of the energy
used in an foundry is directly related to melting and heat treatment
operations.  Integrating heat and power
systems in a foundry through waste heat recovery techniques can lead to energy
reutilization that improves process sustainability and profitability.  The work presented here is an in-depth energy
management analysis using Powersim^TM to identify potential energy
savings through process optimization and advanced control strategies. A system
dynamics model based on the interactions among the major energy intensive
variables has been developed using Powersim^TM to estimate energy
consumption. Our dynamicmodel estimates the monthly energy usage
and its costs for a full calender year. The estimated energy consumption and
its costs have been validated by comparison to the actual plant data obtained
from the Mapleton foundry.

The average metal caster has a
2.4% pre-tax operating profit on sales. This profit is susceptible to
fluctuating utility costs and process disturbances. Since foundry operates with
very thin profit margins it is imperative to ensure that the foundry is running
with efficient process control. Hence, advanced control strategies for the
melters, dust collectors, fans and burners have been proposed and  implemented in the Powersim^TM model
for optimum energy usage. Our results show that these control strategies along
with waste heat recovery techniques could save nearly 18% in energy savings and
$1.8 million in costs annually for the Mapleton foundry.