Liquid sulfur goes to the sulfur burner by precise measurement and fully combusts with dry air to generate SO₂; after cooling, SO₂ gas goes to the converter and convert to SO₃ by vanadium catalyst. After cooling, SO₃ gas goes to sulphonation/sulfation unit; SO₂ and SO₃ gas are cooled by cooling air through tube type heat exchanger; after heat exchanging, the hot air generated in this process is collected and goes to waste heat recovery unit to produce steam and hot water; the secondary hot air will be used for silica gel regeneration and scrubber wastewater evaporation & crystallization in Unit 38.    Features: SO₂ cooler adopts inlet end insulation protection and floating type design, which avoids intergranular corrosion of stainless steel above 600℃, thus the working life can be extended twice as before. By combining the start-up pre-heater and waste heat recovery unit, when preheating the converter, the steam produced also can be used for sulfur melting and generating hot water, so that WEIXIAN plants don't require any external steam.