Abstract: Regarding the existing drawbacks in the current sampling methods for condensable particulate matter (SO₃), the traditional sampling units should be optimized to improve the collection efficiency of SO₃. Several sampling schemes are compared respectively, including vertical and horizontal condenser plate, condensing coil and isopropyl alcohol absorption. The results show that for the capture effect of SO₃ in flue gas, the outcome of the special vertical and horizontal condenser is almost the same, while the two-stage condensate coil exhibits the best performance, followed by the isopropanol absorption method, and the one-stage condensate coil the poorest. Based on this, the best capture scheme coupled two-stage of vertical condenser coil (65℃ constant temperature water bath) with 80% isopropyl alcohol absorption (0℃ ice bath) is put forward, and the onsite testing is carried out. The test results show that SO₃ are captured by all of the above three units. However, the collection efficiency of the first stage condensate coil is the highest, then decreases in turn, and the SO₃ capture ratio of the second stage condensate coil and isopropyl alcohol absorption unit is about 26%~40%.

Key words: coal-fired power plant, ultra-low emission, SO₃, SO₃ collection, controlled condensation, isopropyl alcohol absorption, SO₃ capture effect