Industrial Utility Efficiency    


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.
By making sustainability a requirement and a core element of its growth strategy, Eastman has improved the energy efficiency of manufacturing operations by 13% since its baseline year of 2008 (the year Eastman became an ENERGY STAR® Partner). By 2018, Eastman had decreased its greenhouse gas intensity by 20%, two years ahead of its goal. Additionally, Eastman received the 2019 ENERGY STAR® Partner of the Year Award for Sustained Excellence, marking the company’s eighth consecutive ENERGY STAR award: two years as Partner of the Year and six years of Sustained Excellence recognition.
Reverse pulse type dust collectors often represent a challenge to compressed air energy efficiency, and sometimes throw a wrench into the works by causing huge air pressure fluctuations, high transient flows and just plain large leaks. This article discusses this type of dust collector, often installed in food processing plants, and gives some real-life examples of problematic installations. Some suggested measures are mentioned to ensure your dust collectors keep running in a trouble-free manner.
A flour based frozen foods manufacturer orders a compressed air efficiency audit. The audit establishes the cost of compressed air at $0.27/1000 cubic feet. The study finds the 116 pulse jet dust collectors represent the greatest opportunity for compressed air demand reduction and energy cost savings. A dust collector optimization study/service is suggested and the customer agrees to proceed. In this facility, pulse jet dust collectors are used to filter dust from raw materials entering the plant, for conveying and mixing of ingredients, and for the final packaged finished products leaving the plant.  
One of the most common problems in plants is low air pressure. One of the most common solutions is to purchase new air compressors. Often this advice leads to a poor return on investment with the company’s hard-earned money. Often the issues are related to demand, distribution, or both. Solving the wrong problem can be expensive from a capital and operating cost perspective. Determining root cause analysis may cost more up front, but will save tens if not hundreds of thousands of dollars long term.
A large mining complex in a remote northern region of the world invited a compressed air auditor in to assess the efficiency of a problematic system. Site personnel and their air compressor supplier were concerned a system in one of the buildings was not running optimally, and wanted to know what size of compressor to install in the facility. The auditor found significant savings in this target system, but even larger potential savings were found in other ancillary systems in the complex, as part of an extra investigation conducted while at the site. Overall, the potential energy savings total more than half of a million dollars, if all recommendations are implemented.
The Lafarge Cement Distribution terminal located in Winnipeg, Canada has significantly reduced the site electrical demand and energy charges by changing the way they transport their cement.  Two new low-pressure rotary screw air compressors have replaced two large high-pressure air compressors that previously powered their dense phase transport system.  The resulting power reduction has saved the company 46 percent in transport operating costs.
A trio of stationary compressors produce 630,000 m3/hr of air for the oxygen plant at Pueblo Viejo gold mine in the Dominican Republic. The oxygen is used by its autoclave processing facility to treat roughly 24,000 tons per day of refractory ore for the 60/40 joint venture between Barrick and Goldcorp Inc., operated by Barrick as Pueblo Viejo Dominicana Corporation.
Insufficient focus at the design phase will kill a project. In one aerospace project, insufficient detail was paid to the physical size of the air compressor. The compressor didn’t fit in the allocated space—requiring the extension of the building, and costing tens of thousands of unbudgeted dollars. That had a significant, negative impact on the project return. 
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.
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.