Issues regarding gas condensation and atomization

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In engineering, we encounter a situation where the flow rate is 300 Nm³/min, the velocity is 5 m/s, and the temperature is 200°C. The waste air contains approximately 1.5% (by mass) of chemical gases. We use a condensation method – a five-stage finned tube condenser that cools the air to around 10°C with a flow velocity of 3 m/s, resulting in a saturated concentration of about 0.2% – to remove these chemical gases. In previous projects, thick fog rarely occurred during the condensation process; even if fog was present, it was mild. But recently, thick fog appeared when condensation occurred at ~40°C, and this fog persisted until the end of the condensation process. As a result, this leads to an excessively high liquid content in the exhaust gases. What we need to discuss is: 1. During the previous condensation process, by 30°C the mixed gas had reached a supersaturated concentration and condensate had already formed, but no fog was observed in the gas. Why can’t I see the fog? 2. During the current condensation process: at 40°C, the mixed gas reaches a near-saturated concentration, but no condensate is formed; the gas is already filled with mist. Why are the phenomena so different? 3. How to reduce the liquid content in exhaust gases? Note: The concentration is a theoretical calculation; no actual measurement was taken ； Could changes in composition cause differences in fog (such as the addition of other particles to the exhaust gases)?