OPTIMISATION OF COMPRESSED AIR NETWORKS WITHIN THE MANUFACTURING INDUSTRY

Abstract

Compressed air networks are utilised across many large scale manufacturing industries, such as: aerospace, automotive and construction, often accounting for over 70% of the energy costs of the organisation. However, 75-90% of the compressed air produced is lost to: leaks, inefficiencies or inappropriate usage. By tackling these issues the use of compressed air will be improved to ensure more efficient energy usage and a decrease in energy costs. Network modelling is used to look at complex compressed air networks. A network model is a very flexible and quick tool and allows for a greater number of components to be easily added to the models capability in the future. The network models produced are capable of analysing pipes in series, pipes branching from a single location and pipes branching from multiple locations along a main pipe section. Many network designs were modelled to allow for the analysis of pipe parameter, leak and tool layout effects and the findings can then be implemented into future network designs to improve operation. Methodologies to aid in: the costing and prioritising leak repairs, deciding when maintenance should be implemented and allowing for pneumatic tools to be compared to electrical alternatives are presented. Implementing the conclusions formed within this thesis will enhance network designs for improved efficiency and network operation, leading to reductions in compressed air usage costs. The main conclusions of the thesis are as follows. The effects of pipe diameter changes caused the largest fluctuations to both flow rates and pressures. When the airflow experienced an expansion, within the pipeline, results showed a pressure drop of 50% with an increased flow rate incurring a further pressure drop to 78%. Air lost at a leak is quantifiable using the methodology presented and the costs associated with leaks and repair is also discussed. The network scenario analysed for leak costing showed that a 1mm leak would lose £152 of compressed air per year whereas a 5mm leak would lose £11,631 of compressed air a year. That is a 7550% loss increase through a difference of only 4mm. The effects of different network and equipment layouts is analysed and it was concluded that high pressure tools should be located earlier in a network layout for improved network efficiency. Separating networks is also investigated. A mix of six pieces of equipment were placed onto a single 7bar network; upon splitting the tools it was found that the two separate networks could operate on reduced pressures of 6.1bar and 5.6bar. This created a huge operational cost saving of £17,521 per year. Finally, an analysis of the current and the future manufacturing industry is discussed along with a methodology for comparing pneumatic tools to their electrical alternatives. The example presented, of a single air drill and electrical drill, showed a cost saving of £2,583 per year

Date of Award	13 Jun 2018
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Iain Dupere (Main Supervisor)