Reduced Specific Energy Consumption
The glassy nature of Slagomite, combined with its chemical composition, leads to faster melting. As a result, the energy required to melt the glass, while maintaining existing furnace temperatures, is actually lower. Depending on the specific furnace design and control parameters, this can be used to reduce the total energy consumption/ton of glass, or specifically to reduce the use of electric boost.
The following graphs illustrate examples where the use of Slagomite has reduced the specific energy consumption. In all examples, the data are separated according to the three stages; without Slagomite, while Slagomite is being introduced, and with Slagomite in the batch. The savings quoted are based on the average values before and after the introduction of Slagomite.
Introducing Slagomite to the amber container glass, figure 3.1, led to a 4.2% reduction in the overall energy consumption/ton of glass, which was maintained with the continued use of Slagomite in the batch.
The introduction of Slagomite for a trial period in a green container furnace, figure 3.2, showed an average reduction of 3% of the total energy consumption over the trial period. The maximum energy reduction was 5%, which was achieved in conjunction with furnace temperature reductions and glass quality improvements.
Reduced Furnace Electrical Consumption
The faster melting with Slagomite often leads to a direct increase in furnace bottom temperatures. This can be used specifically to reduce the power to the electric boost system and hence reduce the electrical energy consumption. This is illustrated with the following example from a green container furnace with 13% Slagomite , when the electrical energy consumption was reduced by over 30%. Despite this significant reduction in energy consumption, the bottom temperatures were on average 10°C hotter during the trial period than when Slagomite was not in use, indicating potential for further energy reduction.
Increasing Slagomite Usage
For existing users of Slagomite , it is worth noting that increasing the level of Slagomite used in the batch would be expected to offer similar energy savings, whether in terms of total energy consumption or specific electrical energy reduction. For example, increasing from 6% to 12% in a green container furnace would be expected to reduce specific energy consumption by 1.5% - 2%.
Energy Savings
In the current climate of increasing energy prices, the value of Slagomite as a means of reducing energy consumption is increasingly being recognized. Use of Slagomite has been proven to reduce energy consumption in all types of soda-lime-silica glass production, including cosmetic flint, float, and fiber glass.
The level of energy savings achieved will be dependent on the specific furnace, along with factors such as glass color and cullet level. However the regular use of Slagomite will reduce overall energy consumption by 4-5%.
The average energy saving through the use of cullet is typically 2.5% energy reduction per 10% cullet increase. Therefore, the use of Slagomite can lead to savings equivalent to increasing the cullet level by up to 12-16%.
Increased Glass Yield
The use of Slagomite results in more glass produced per ton of batch melted, as there are no products of decomposition produced as Slagomite reacts in the batch. The increased yield varies from 1.3% in flint glass to 3.2% when Slagomite is used in amber glass.
Increased Furnace Pull
The faster melting with Slagomite can lead to increased furnace pull, without the need to increase furnace temperatures or specific energy consumption. In a number of cases, with the introduction of Slagomite , furnace pull has been increased beyond the design output of the furnace and beyond the previous maximum pull that had been achieved. Increased production beyond this previous maximum results in extra financial contribution on all additional tonnage.
Improved Glass Quality
Slagomite reduces seeds in the glass by over 50% on average. It also reduces the tendency for blister and batch stones that are often rejected by inspection equipment. A modest 0.25% reduction in scanner rejects for a plant manufacturing 600 tons per day of glass would allow an additional 150m2/day of float glass at 4 mm or 7,500 containers per day at an average of 200g to be packed.
Increased Furnace Life
A typical furnace rebuild costs approximately $14,000,000. Therefore, an extension of campaign life of just four months through the lowering of furnace temperatures using Slagomite would offer significant cost advantages.
Batch Simplification
Use of Slagomite can potentially result in simplification of a batch recipe due to the range of oxides that it contains. In many cases, Slagomite is used as the sole alumina source. If this advantage can be considered during the design stage of a glass plant, then huge capital sums can be saved if the batch plant design can be simplified to accommodate fewer raw materials.
