Foaming issues will depend on the cleanliness of the feed. Hydrocarbons, organic compounds, additives and particulates will all act to promote/stabilize foam. The best solution is to make sure it is clean, this means proper filtration, best is to have a particulate filter, activated charcoal filter and an afterfilter for removal of charcoal fines. If a significant amount of liquid HC is expected, a liquid/liquid separator is required.