Extended Lifetime and Enhanced Cleanliness of Air Compressor Oil with Innovative OSP Technology

摘要

Air compressors are widely used in the manufacturing and construction industries. The main performance requirements of premium air compressor oils are good temperature-viscosity performance, oxidation stability, corrosion protection, fluid and equipment cleanliness and adequate lubrication and cooling between moving parts. The market trends for air compressor oils are longer life fluids and reduced coking and varnishing especially for those based on hydrocarbon oils. Controlling deposit formation (including varnish, sludge, coking, etc.) is a very common challenge for air compressor lubricants which can seriously impact equipment reliability. Varnish and sludge can hinder air compressor performance, especially under high temperature or high humidity conditions. These deposits will cause issues when they form in the cooler, oil separator and air end, leading to significant extra energy consumption and the risk of shutdown. PAG (Polyalkylene glycols) have significant advantages over hydrocarbon oils to combat deposit challenges in air compressors. The conventional PAGs derived from copolymers of ethylene oxide (EO) and propylene oxide (PO) or homo-polymers of propylene oxide are known to operate in rotary screw air compressor equipment with more favorable deposit control benefits than hydrocarbon oils and have been used for more than 30 years in compressor equipment[1] However, conventional PAGs are not miscible with hydrocarbon oils, which limits the possibility of formulating semi-synthetic fluids that combine conventional PAGs with hydrocarbon oils. UCON Oil-Soluble Polyalkylene Glycols (OSP) are a new type of PAG technology recently developed by Dow Chemical, and are compatible with hydrocarbon oils and retain many of the advantages of conventional PAGs. This enables hydrocarbon based lubricants to be developed that include OSPs which can improve the deficiencies of hydrocarbon oils by providing excellent deposit control, long lifetime, outstanding air release property, etc. [Z3] UCON OSPs are available in viscosity grades ranging from 18 to 680 cSt (kinematic viscosity @ 40°C). These new Group V base oils can be used as additives or co-base oils in formulations to help formulators meet the current and future technology challenges. There are several other critical requirements placed on the air compressor oils, including low foam, fast air release, good corrosion protection, effective cooling, etc. OSPs have shown benefits in controlling foam and in improving air release times. OSPs are also known to boost the efficacy of ferrous based corrosion inhibitors. One major functionality of air compressor oils is efficient cooling to maintain the proper operating temperature of air compressors. OSP offer higher volume heat capacities than hydrocarbon oils which may lead to slow oxidation rates and longer fluid life. Finally in some compressor applications, it is known that synthetic esters are used particularly in high temperature oxidative environments. However in wet air environments, esters are prone to hydrolysis, leading to acid generation and fluid degradation. The inclusion of an OSP to synthetic esters can lead to improvements in hydrolytic stability, and extended fluid lifetime. This presentation provides a technology overview of OSP as a performance booster for air compressor oil application. Successful customer cases are also discussed.