Industrial Utility Efficiency
Nitrogen is used in many facilities for a variety of purposes. The most common source of N2 is through the use of bulk liquid storage. A plant owner was recently surprised to learn that a large portion of his N2 was disappearing, without ever being used by his production process. This article discusses where it went and what we could do about it.
In the field of externally heated adsorption dryers there is a large variety of different systems on the market offering substantial flexibility in terms of process flows, dew points and energy demand. Often, economic parameters and project-specific requirements ultimately define the individual user-specific solution. This article discusses the basic types of desiccants used in compressed air dryers.
This article is intended to show the relationships between risks and specifications, opportunities and responsibility in validation, and in particular, the use of modern and calibrated measurement technology in the sample chain.
Often when you mention heat of compression the first thought generally relates to HOC desiccant dryers, which are also an under-applied opportunity for heat recovery. However, there are many other heat of compression recoverable energy savings opportunities in all compressed air and gas systems. This article reviews many opportunities in energy heat recovery and provides answer to commonly asked question.
As part of an energy reduction effort, a Canadian technical college hired a compressed air auditor to do a leakage audit of their large campus, which houses over 30 mixed use buildings, including laboratories, research facilities, shops and classrooms. The audit found very few leaks, the reduction of which would achieve minimal savings; however, a few surprising items of interest were noticed during the study that showed very good potential for operating cost savings of 64% with an estimated \$45,000 per year in reduced energy and water costs. This article discusses some of the findings and how savings can be achieved on lightly loaded compressed air systems.
This major food manufacturing plant in the Midwest uses compressed air and onsite nitrogen generation to operate multiple snack production and packaging lines. The plant spends an estimated \$430,344 annually on energy to operate its compressed air system based on an average rate of 4.5 cents per kWh.
Experienced auditors become wary when they see desiccant dryers installed in customers’ plants. These dryers are required when a plant needs instrument-quality compressed air, or when compressed air piping is exposed to freezing temperatures. However, while desiccant dryers can gain this level of quality, the energy cost of stepping up from a dewpoint of 35 oF to a level of -40 oF increases quite considerably. To attempt to reduce the energy costs of drying to these low levels, heated blower desiccant styles may be used. This article describes three common desiccant dryer types, as well as some experiences, good and bad, with heated blower types.
The University of Manitoba Bannatyne Campus, Canada, upgraded its compressed air system to include variable speed drive (VSD) air compressors and the use of internal heat-of-compression (HOC) drying, replacing oil-free air compressors and refrigerated dryers that reached the end of useful life. In doing so, the campus reduced annual energy consumption by 15%, improved the quality of the compressed air to modern day instrument air standards and gained additional compressed-air capacity. The local utility also awarded the medical campus an incentive of \$13,500, offsetting the cost of the initiative.
A pharmaceutical plant, has had a compressed air assessment performed on two plant systems. The studies uncovered poor compressed air production efficiency, high air dryer loss, and problems with high flow compressed air uses negatively affecting plant pressure. The plant implemented energy efficiency measures, on the two compressed air systems, saving 46 and 64 percent in energy costs respectively.
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.
Compressed air contains contaminants such as dirt, water and oil which must be removed before use. ISO8573.1 specifies air quality classes for these contaminants. Humidity is expressed in terms of Pressure Dew Point (PDP). PDP is the temperature at which air is fully saturated with moisture, when the air temperature falls below this point further condensation will occur.
