Industrial Utility Efficiency    

Blow-off Air

The snack food facility is running with two normally separated compressed air production systems: the main plant system and the nitrogen system.
Many manufacturing processes are like offensive linemen. When everything is running smoothly, nobody tends to notice. But, when an application starts creating a hazardous work environment (think too many blindsided sacks), or the products start spoiling (think shutout or a losing season), you best believe someone will start paying attention.
This food & beverage plant is a large (500,000 sq ft) meat processing plant with twenty packaging lines and nine palletizers. The compressed air system is supplied from three separate rooms with seven individual lubricant-cooled, single and two-stage rotary screw compressors. The plant has four blower purge desiccant dryers designed to deliver a - 40°F pressure dewpoint.
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. 
Bottling companies and breweries, in California, are benefiting from a three-step system assessment process aimed at reducing the electrical consumption of their compressed air systems. The three-step process reduces compressed air demand in bottling lines by focusing on open blowing and idle equipment, and then improves the specic power (reducing the energy consumption) of the air compressors.
Many times, the hierarchy of making improvements in your compressed air system will begin with the larger equipment. If your compressor is outdated, inefficient or sized improperly for your plant, the cost of replacing it may scare you away from proceeding down the efficiency path. It is also typical to first concentrate on updating the controls of a compressor to best match peak demands and lulls in the need for air and, while this is a very good step to take in your overall plan of attack, it can also burden your budget.  
Assessing payback on engineered air nozzle and blower upgrades There are a variety of means factories can use to remove or “blowoff” moisture from a package. Open tubes or drilled pipe are often viewed as simple low-cost methods. However, there are considerable drawbacks to these approaches, most notably – increased operating expense. While they may be convenient and inexpensive in the short term, these approaches often cost 5-7 times more to operate than preferred alternatives.
Recently, The Kroger Company’s Indianapolis bakery identified the use of compressed air in a blow-off and conveyor gap transfer as a major source of energy loss and cost waste. According to the U.S. Department of Energy, “inappropriate use” of compressed air like blow-off produces high pressure atmosphere bleed leading to significant energy loss and unnecessary operational costs. Carrying a 10-15% efficiency return (according to the Department of Energy), compressed air applications can often be achieved more effectively, efficiently and less expensively with alternative solutions using a high flow rate and moderate pressure.
This factory currently spends $735,757 annually on the electricity required to operate the compressed air system at its plant. The group of projects recommended in the system assessment will reduce these energy costs by an estimated $364,211 (49% of current use). Estimated costs for completing the recommended projects total $435,800. This figure represents a simple payback period of 14.4 months.
Over the last several decades, Air Power USA has reviewed many various types of plastic injection molding operations throughout the U.S.
Relatively few people realize that for a variety of industrial manufacturing applications, from air knife drying to simple blow-off nozzles, the use of high pressure compressed air that bleeds into the atmosphere represents a significant waste of energy.