Issue link: https://www.e-digitaleditions.com/i/1366075
34 / May 2021 powderbulk.com COMPRESSED AIR — PART I: REFRAMING SYSTEM IMPROVEMENT COST DECISIONS Compressed-air systems are essential to many powder and bulk solids handling processes. However, when confronted with compressed-air system issues, instead of tackling the problem and repair costs head-on, many plant managers look for shortcuts even though this can cost more money in the long run. Part I of this article uses real-world examples to detail some compressed- air system problems and discusses how rethinking the costs involved in fixing these issues can benefit your operation. Paul Edwards, Compressed Air Consultants air demand and more effectively running the mine's new $600,000-plus compressed-air system. The majority of the system's waste was in the dewa- tering diaphragm pumps. The mine had more than 120 diaphragm pumps, and of the 40 surveyed, 80 percent were pumping dry. Of the 3,600 scfm of air being consumed, 1,500 scfm was going to diaphragm pump waste. When the mine superintendent was told that the operation could save 42 percent (more than $300,000) of the mine's operating costs with a payback of 18 to 21 months — but that this would require the mine to dig small pits and install a float to control diaphragm pump air consumption — the superintendent said that if holes were going to be dug, they would be "for coal." When possible outsourcing of the digging was sug- gested, which would still have saved a lot of money, the superintendent said the mine didn't outsource digging. C ompressed-air systems are necessary in many processes involving powder and bulk solids. The systems are used for everything from pow- ering equipment and transporting material to heating and cooling parts of your process. System components include not only compressors, filters, and dryers but also the piping or ducts, storage tanks, and process equipment that uses or interacts with the air. While compressed air isn't a glamorous part of your business, tending to these systems and making sure they're operating at their highest potential is beneficial to your bottom line. Often, when a compressed-air system is experiencing issues, plant managers look at the problem and only see an expensive equipment repair or replacement, or they think "I'll get around to that when I have more time." What is less apparent is the money being spent — and sometimes wasted — by continuing to operate these systems inefficiently or at a less-than-optimum level. Through real-world examples, this article will explain how viewing the costs involved in fixing compressed- air system problems from the right busi- ness perspective can help your operation save money in the long run. Defining the problem Several years ago, an audit needed to be done on a coal mine's compressed-air system, as shown in Figure 1. There were three primary places underground and one place above ground that the compressed air went: • powering belt splicing tools • driving diaphragm pumps • feeding leaks • supplying desiccant dryers (above ground) The audit found that the majority of improvement opportunities would come from reducing compressed- FIGURE 1 Installing a new compressor station was avoidable for the coal mine.