Abstracts for upcoming presentations

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"Smart Thyristor Control of Power Supply on Electric Boosting Systems provides Potential Energy Savings"

"Improving the Profitability of Glass Production through Operational Decision Support"

There are of course physical limitations to the interesting ongoing, commercial strive for higher glass furnace pull rates. One of those constraints is of course the maximum temperature that the crown refractory has to withstand, which has a direct correlation with the amount of energy that can be applied by combustion of fuel. To enable the input of more energy, without the side effects of higher superstructure refractory temperatures, there is another method which we all know as electrical boosting. Not only is boosting  capable of applying potential amounts of energy to the melt it is also capable of providing better control of glass melt flow currents, and stirring effects,  resulting in better and more efficient fining processes (especially in case of barrier boosting).

Electrical boosting is in principal a very efficient method of energy transfer especially as long as the system that provides the electrical power is built in line with the latest technical standards. The paper will describe how multiple zone SCR (silicon controlled rectifiers) boosting systems provide an optimum of power control and power distribution.  It will illustrate how to avoid typical “hot spots” and provide the highest efficiency through the use of “Predictive Load Management” and burst firing (full sinus wave) methods. Historically SCR controlled boosting system used phase angle firing, also called phase cutting, which is a method of pulse width modulation (PWM) for power limiting, applied to AC voltages. The main disadvantage of this phase angle SCR firing method is that it courses relatively high reactive power content and harmonics. Only active power is capable to apply energy to the process, reactive power has to be seen as energy losses. Burst firing mode consists of supplying a series of whole mains cycles to the load. It works by modulating a SCR into and out of conduction only when the alternating current waveform passes thru its zero crossing. Burst firing minimizes the reactive power content and thereby it improves the SCR systems efficiency. To take away the possible disadvantage of unwanted simultaneous bursts of multiple boosting zones firing at the same time, which will course unwanted peak power demands, a predictive firing strategy is used to synchronize the zones’ firing and thereby optimize the total power consumption of such a multiple zone SCR system. It will also explain how different boosting system designs, using higher intermediary voltages and super compact water cooled transformers contribute in less energy losses, greater electrical power efficiency and power factor improvements, system standardization, more cost effective system designs and optimum stable glass melt flow patterns.

Water cooled transformers allow the units to be epoxy sealed allowing them to be located in environments have containment.  With this and due to the ambient temperature of the water cooled transformer being the inlet water temperature, the water cooled transformers can be located closer to the load of the circuit reducing the losses in the system.  These losses are both resistive and reactive and will decrease the power used and increase the power factor of the system.

A number of major transitions in the business of industry have occurred over the past five year which have impacted industry in general, and glass production in particular. Among these transitions, perhaps the most impactful has been that the business variables of industry have shifted from highly stable over extended periods of time to almost real time variability. For example, only a decade ago most industrial companies developed contracts with their electricity suppliers that essentially relegated the price of electricity to a constant over the contract period, which could be as much as a year. Today, the price that industrial companies pay for electricity can change multiple times in a single hour.  The profitability (earnings) of glass operations with traditionally very predictable profitability levels appears to be out of control. The new industry drivers require new operational business excellence processes and approaches. Not only does the efficiency of glass operations need to be controlled, but also the business variables of glass operations require control. Because the business variables change with such high frequency, the business control system must be able to respond accordingly. Traditional monthly accounting systems do not do respond quickly enough so a new, higher frequency control approach is required.

This paper will investigate the current business forces that impact the glass industry and show approaches to “business control” based on the deployment of a high frequency decision support infrastructure from the plant floor through all levels of the operations and business.

By measuring the business variables (such as production value, energy cost, material cost, environmental impact and safety risk) in real time, empowering the operational and business personnel with the information they need in the time-frame in which they need to make good business decisions, and alleviating the critical constraints on profitability, glass operations can attain new levels of profitability even in this daunting business environment.