Unless you have been in a cave over the last few months, energy consumption and costs have taken over the nation's conscience. Our shrinking industrial base must be wise consumers of our resources such as gas and electricity to remain
competitive. Within the metals industries, in particular Aluminum manufacturing, large amounts of gas and electricity are
required to generate end product. To generate 1lb of aluminum from alumina, requires about 6.2 kWH (kilowatt hours) of
electricity. Once the raw material has been created, aluminum is casted into furnaces or smelters, requiring about 1100
BTU's per lb to liquefy.To examine further, 1 SCF (Standard Cubic Foot) of natural gas can generate a range of 800 - 1100
BTU's. It takes roughly 2100 Btu/lb to melt aluminum to allow for casting. Given a large ingot of 30,000 lbs, the number of
BTU's needed will equate to very large natural gas bills.
In order to ensure Natural Gas usage remains constant in relation to the manufactured lbs, Deadline Solutions, Inc. has
come up with a solution to provide reporting and trending of natural gas usage within the Aluminum industry. In order to
accomplish these goals, two key variables need to be harvested, gas usage in SCF and lbs produced over time. The
consumption and processing of these variables would become the Energy Analysis + Monitoring System (EAMS).
Who is using the gas?
Within most aluminum facilities, there are a number of existing natural gas meters in place to help trend the gas usage.
One of the first obstacles to overcome is the wide disparity of control systems within the factory floor that contains the
flow data in units of SCFH. Some aluminum manufacturing facilities will have a casting group, cold rolling and hot rolling
facilities which may contain different manufacturers of control systems from GE to Siemens. To solve this problem,
Deadline Solutions selected Kepware Technologies to provide a landing zone of all natural gas readings into one process.
Kepware manufactures OPC (OPen Connectivity) software that can speak the various PLC (Programmable Logic Controllers) found
within the site. Deadline Solutions was required to solve this problem by connecting to Allen-Bradley, various Modbus
devices, Yokogawa and GE 9070 PLCs. Right out of the box Kepware has a solution for each of these devices providing a
single source concentrator of OPC data. With all of our OPC data contained in one location, trending and management of
these variant natural gas flow meters becomes routine.
In order to obtain a higher degree of accuracy, secondary natural gas flow meters where installed to fill the gaps of
existing meters. Use of wireless technologies was employed to save on material and labor costs. The secondary network
consisted of wireless RF modems providing coverage over the entire site. Essentially the wireless flow meter configuration
could be placed anywhere required with the facility with no concern of location of dependant resources such as wired LAN
connectivity. Base stations where designed at key locations that would accept the wireless data and ground it to the
automation LAN. Once the data was available on the LAN, the Kepware Modbus driver was used to collect and store the flow
data to EAMS.
Having flow data is trended over time; the consumption of gas is computed to the hour or day as the base unit. Gaps in
data would cause under-reporting of gas consumption with EAMS. The reliability and stability Kepware OPC Servers to collect
the flow data is fundamental for the EAMS system to be successful.
What did we do?
As with our flow meters, production data presents a similar challenge with different MES/Level 3 systems used within the
facility. The production data was harmonized into a common format so it could be understood by computation logic within
each plant area. Putting software engineering best practices to use, Deadline Solutions built a web services layer in front
of each of the manufacturing units. Web services provided endpoints which could transgress routed and firewalled
environments. Each area contained a web server that published there lbs data. Using web services (WS-*) provide the
contractual data format and security standard to harmonize the information into a central store. Much like our natural gas
usage, the production data is now stored in a consistent uniform manor across disparate systems.
Did we conserve our resources?
By marrying two technologies, Web Services and Kepware OPC data, the EAMS system now has the data inputs required.
Reporting and reviewing of natural gas consumption over production is a much easier task. Answers to questions such as
how much gas was used? How many BTU's per lb where used? Is the furnace or process more efficient this week from last
week? Being able to answering these questions provides feedback to maintenance and process folks to tune their devices and
processes. Being able to tune your world enables manufacturers to be conservationists of energy rather than simply users.
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