CARBERY MILK PRODUCTS LTD.,
BALLINEEN, CO. CORK
Carbery Milk Products was established in 1965, and since then has evolved into a leading international food company producing a successful range of food ingredients and cheese and ethanol products. Compressed air is an essential part of the production process at Carbery. It is used for a variety of process and instrument applications. The annual cost of generating compressed air for the plant was calculated to be €102,000.

Compressed air is generated at four separate locations at the plant, each location supplying individual systems. These consist of a main factory system and 3 satellite systems, namely the alcohol plant, the cheese plant and the digester plant. All systems are linked for backup purposes, although the links are usually closed. A summary of the systems, their compressors, and treatment systems is presented in Table 3 above.

The site suffers from problems due to low air pressure during spring and summer time when milk production is high. Management is active in trying to reduce energy consumption with a comprehensive site monitoring system connected to a number of electricity meters and also various flow and other meters.

Measurement of Air Demand & Quality
The air delivered from each compressor station was measured over a period of a week, including isolation of specific plant to investigate leakage rates.
The air quality delivered by each system was also measured. Evaluations of the results of these measurements led to the following conclusions:
»    The large amount of small bore nylon pipe used in the plant was contributing to the plant’s pressure drop problems. Long lengths of narrow bore nylon tubing should be replaced with steel pipe work.
»    The night/non-production time demand was quite high, indicating a high leakage rate or misuse of air.
»    €1060 a year could be saved by shutting down the alcohol plant compressors overnight, when all the fermenters are not in use.
»    There was a problem with pressure drop in the cheese area when the cheese cutters were operating. This could be improved by re-piping the air booster arrangement to feed the accumulator before supplying the process.
»    Air efficient nozzles should be fitted on the labelling machines in the cheese plant.
»    Solenoid valves should be used throughout the plant to switch off the air supply when a machine is not in use.
»    €4,000 per year could be saved by linking the alcohol plant and the main factory compressed air systems.
»    €3,100 to €5,740 per year could be saved by linking the main factory and digester compressor.
»    €4,000 per year could be saved by supplying most of the cheese plant system from the factory air.

System Leakage
A comprehensive leakage survey using ultrasonic leak detection equipment was carried out as part of the audit and a total of 78 leaks were identified. Fifty of these leaks were medium to very large in size. It was determined that carrying out a comprehensive leak reduction programme as part of a planned maintenance system could achieve an annual saving of €28,400.

Recommendations
The audit identified a total savings potential of close to €42,200 for the Carbery Milk Products site. The main recommendations for savings lie in reducing leakage, which is currently very high, and linking the compressed air systems. 19 other recommendations were also made for individual plant areas covering items such as flow meter recalibration, upgrading nylon airlines, installing automatic drains and air efficient nozzles at the end users.