Combustion installations for biofuels; gas scrubbers being parts of gas installations; cooling and drying installations for gases; gas cleaners and purifiers, namely, gas scrubbers and gas purification machines; gas collection installations, namely, gas separators for the cleaning and purification of gases, gas filtration units being gas filtering installations, and gas purification installations; gas drying devices, namely, biogas dehumidification units, electric gas dehydration apparatus, a...