Making cement is an energy-intensive process. In a cement plant, the electrical energy load can reach up to 25 MW, consuming 185 million kilowatt hours of electricity annually. In addition, the plant consumes a large amount of coal and natural gas. CalPortland is an enormous producer of cement, concrete, aggregates and asphalt. With 80 facilities spanning five states across the western U.S., one might logically assume that CalPortland consumes a lot of energy.
For Imerys S.A. there’s little question about the importance of managing dust collection systems it uses to control and reduce harmful particulates in its worldwide minerals processing facilities. And now there’s zero doubt about the tremendous energy savings it stands to save by reducing the amount of compressed air needed for these same dust collectors.
Cement production facilities have a significant number of dust collectors. Many have continuing problems with short bag life and low-pressure problems at the further points from the central air system. They often run on timers. When they try to run on demand control, they often get extreme short cycling, which causes even more bag problems. Most have gauges at the entry, on at least half of the dust collectors, and the compressed air feed lines are always the same size as the connector opening. This article reviews where these problems come from and provides some troubleshooting ideas.
Vale in Thompson, Manitoba, Canada has reconfigured a system of large turbo compressors in their mining, milling, smelting and refining operation and gained very large energy savings through a series of improvement projects. In addition, these projects qualified for some significant financial incentives from their local power utility. Vale is a large multinational mining company with headquarters in Brazil. Vale operations focus on the production of iron ore, coal, fertilizers, copper and nickel. The Thompson Manitoba operations consist of mining, smelting, milling, and refining of Nickel in the 250 acre complex that employs 1,500 people.
The plant air system consists of eight, single-stage, lubricated, Sullair rotary screw compressors. All units are in good working order. Units 2, 3, 4 and 7 are water-cooled and units 6, 8, 9, 10 and 11 are air-cooled. The main plant air system has two primary compressed air dryers, a Thompson Gordon model TG 2000 refrigerated dryer, and a Sullair model SAR 1350 heatless desiccant dryer. Both units are working according to their design. The TG 2000 uses approximately 11.2 kW and is a non-cycling type unit, and the SAR 1350 uses approximately 200 cfm of purge air to regenerate the wet tower.
In thermal power stations, nuclear plants, and chemical and industrial plants, different types of bulk materials are used. The materials exist in different forms including lump, powder, granules, chips, and pallets. These bulk materials, in their different forms, require efficient and reliable material handling systems.
In many industrial plants there are one or more applications with intermittent demands of relatively high volume. One example is the use of dense phase transport systems to convey the cement. Dense phase systems can cause severe dynamic pressure fluctuations affecting quality of the end product in a plant.
Portland cement companies combat heavy dust, reclaim product and enhance quality control using a variety of vacuum cleaning applications.
In many manufacturing operations, a very significant compressed air use is pneumatic conveying of many types of materials such as cement, fly ash, starch, sugar, salt, sand, plastic pellets, oats, feeds, etc. Often these are systems that use high-pressure air (100 psig class) reduced to lower pressures (15 psig, 45 psig). This creates an air savings opportunity.
Sitting on his desk the day Brian began his new job as Plant Engineer for Carbo Ceramics’ McIntyre, GA facility was a proposal to purchase a new 150 HP air compressor as a backup machine. The facility already had six of these machines and, yes, all six ran almost continuously.
A compressed air system assessment saved this building materials manufacturer over \$518,000 per year in energy costs, with a simple ROI of 11 months.