This article reviews key Mine Safety and Health Administration (MSHA) requirements affecting compressors, air receivers, pressure systems, piping, hoses and compressed air use. It also examines common field hazards, inspection and maintenance considerations, equipment safety requirements and worker training provisions. Practical examples illustrate how mine operators and compressed air professionals can identify potential hazards and improve safety while working within the applicable MSHA framework.
An air compressor, no matter its renown, is merely one leg of a four-legged stool. To stay upright, to support your business effectively, it needs the stability provided by the other three legs: system design, service provider and manufacturer. Overlook one in favor of brand and you add risk.
The purpose of this article is to show there isn’t always a proportionally linear relationship between what happens with flow reductions on the demand side of a compressed air system - and what happens with the energy consumption in the air compressor room. Optimizing an entire compressed air system requires precise knowledge of the supply side, how compressed air is used in the process itself and how those two relate together.
There are some fundamentals when it comes to compressed air system improvements. One strategy that is overlooked is just drawing the details of whatever aspect of a system you are looking at. It is fairly common to see a misdiagnosis of some particular technical issue that would have been obvious should someone have created the drawing to describe the problem.
One observation I’ve made from 30 years of working with compressed air systems is to never underestimate the ingenuity of plant personnel when it comes to misapplying compressed air. We see something new in virtually every plant we visit, but one of the more common problems we encounter involves the use of expensive air for bearing cooling.
Replacing unreliable air compressors is often a smart choice. Sometimes there is a better one. Take the case of a wallboard plant with two compressed air systems, including one for its board mill and another for its rock mill. Each had two 100 horsepower air compressors, all of which constantly overheated. When they did, plant personnel had to scramble to turn on a machine manually every time a unit shut down. Three units ran the plant so any shutdown had them walking on pins and needles.
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.
When Compressed Air Consultants was starting, in 2003, we were approached by a company experiencing significant problems with their compressed air system. They had compressed air pressure problems causing production interruptions. They had moisture issues causing all kinds of havoc throughout the facility and appeared to be using far too many air compressors for what they wanted to accomplish.
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.
Compressed air audits for chemical and petrochemical plants have many characteristics in common with audits in other industries, but there are some differences in the way these businesses run that impact the goals of the typical audit and how that audit is conducted. In chemical and petrochemical facilities, the reason for auditing the demand side is different than that of other industries. Additionally, there are frequently applications with opportunities for improvement that are not always seen in other industries.
The purpose of the audit is to improve reliability throughout the facility. Reliability on the demand side can be defined by having adequate air pressure and air quality at all times throughout the facility. This outcome is a function of both the operation of the supply side in the operation of the demand side. If a demand problem occurs, such as a dust collector pulsejet failure, it can reduce the air pressure in a local sector. If a compressor fails, any backup compressor takes too long to start, the pressure would drop in this circumstance too
Keeping an open mind is critical in all system assessments. Each client has different priorities and circumstances. In this case, the elimination of the “close-scrapes” with insufficient pressure was the priority. The energy and rental/maintenance savings realized were just an added bonus. In this article, we have focused on the supply-side of the system and how the centrifugal compressors could be made to supply the system reliably – without the need for rental air compressors.
