Furnace campaign

Van Vlack [42] observed that the bosh region contained alkalies in excess of the requirements of kaliophilite and nepheline. This excess did not result in the formation of alumino-silicate or silicate minerals of higher alkali content but was present as alkali carbonates. The carbonates formed toward the end of the furnace campaign from the free alkali deposited in the bosh lining. For the particular furnace examined, Van Vlack determined that alkali-bearing minerals were present only where porosity and proximity of the surface permitted expansion. Therefore, the presence of alkalies did not prove seriously detrimental in the bosh and... 

The refractory tends to degrade much faster in these furnaces, resulting in very short furnace campaigns, typically less than 2 years. Most of these furnaces are less than 40 ton (361) of glass per day however, furnaces as large as 200 ton (1801) per day have been built.6 A typical electric melter is shown in Figure 7.2. 

The previously described improvement in plant availability and the achieved increase in material throughput are also attributed to extended furnace campaigns. The refi actory lining of the converter was qualitatively and geometrically reformed over the last years as shown in Figures 5 and 24. The insertion of a so-called step -type injector resulted in a significantly... 

These in-situ AZS thickness sensors, with the hand-held sensor, can be integrated together with the furnace tomography sensor system to create a self-monitoring smart furnace technology to avoid costly leaks and optimize furnace campaign. All furnace health and statu s data can be... 

Glass industry can benefit from thorough evaluation of post-campaign samples of bonded AZS pavers, vibro-cast AZS and alumina products. Such a study, coupled with glass defects data from furnace campaign, can be immensely useful in determining the cost vs. benefit of using lower-cost refractories. 

Figure 9 Seventy percent alumina brick after a short arc furnace campaign.

Most glass is melted in large (continuous) tanks that can melt 400 00 t a day for production of other glass products. The process is continuous with the raw materials fed into one end as molten glass is removed from the other end. Once the process (called a campaign) is begun it is continued indefinitely, night and day, often for several years until the demand is met or the furnace breaks down. 

About fourteen per cent, of coke are consumed, and the products arc sixty per cent, of lead, and twenty-four of matt rich in lead. Most of the soorlse are rejected. The campaign, or smelting period, continues six days uninterruptedly, in which time thirty tons or more are smelted on an average. The poorer ores, yielding only fifty per cent, of lead are smelted in a high-blast furnace. 

A preliminary investigation on dioxin emission from MSWI in China has been campaigned by Tian and Ouyang (2003). Flue gas of 15 different types of MSW incinerators was monitored. About half of the data exceeded the national standard for dioxin emissions limit (1 ng TEQ m-3 National Standard of the People s Republic of China, 2001) and the highest was at 100 ng TEQ m-3 level. However, this report did not provide precise concentrations. Total dioxin emissions to air from MSWI was estimated to be 72 ng TEQ annually in China based on the monitoring data of Tian and Ouyang (2003). Stack furnaces (with bag filters for dust removal) are the major type of MSW incinerators in China but not the major contributor to dioxin emissions. Fluid-bed furnaces accounted for 60% of the dioxin emissions from MSWI. 

Studies regarding the reactions between sodium carbonate and potassium carbonate vapors and refractories have been limited in scope. (Many studies conducted by industry may not have been reported in the literature.) The majority have involved the examination of the degenerated features of refractories after an average service campaign. Most of the articles published have concerned the reactions between alkalies and alumino-silicate refractories utilized in glass melting and blast furnaces. 

To allow for long campaign operation the following measures need to be taken apply a more persistent refractory lining of the shaft, bottom and the hearth apply water cooling of the furnace wall this keeps the wall temperature low and thus prevents rapid wearing of the hearth lining... 

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