In this work, fly-ash water scrubbing experiments were conducted in a three-stage lab-scale dual-flow sieve plate scrubber to observe the performance of scrubber in fly-ash removal at different operating conditions by varying the liquid rate, gas rate and inlet fly-ash loading. The percentage of fly-ash removal efficiency increases with increase in inlet fly-ash loading, gas flow rate and liquid flow rate, and height of the scrubber; 98.55% maximum percentage of fly-ash removal efficiency (ηFA) is achieved at 19.36 × 10(-4) Nm(3)/s gas flow rate (QG) and 48.183 × 10(-6) m(3)/s liquid flow rate (QL) at 25 × 10(-3) kg/Nm(3) inlet fly-ash loading (CFA,i). A model has also been developed for the prediction of fly-ash removal efficiency of the column using the experimental results. The predicted values calculated using the correlation matched well with the experimental results. Deviations observed between the experimental and the predicted values were less than 20%.

The objective of this study was to observe the performance of a lab-scale three-stage dual-flow sieve plate column scrubber for hydrogen sulfide (HS) gas removal from a gas stream, in which the HS concentration was similar to that of gasifier syngas. The tap water was used as scrubbing liquid. The gas and liquid were operated at flow rates in the range of 16.59 × 10-27.65 × 10 Nm/s and 20.649 × 10-48.183 × 10 m/s, respectively. The effects of gas and liquid flow rates on the percentage removal of HS were studied at 50-300 ppm inlet concentrations of HS. The increase in liquid flow rate, gas flow rate and inlet HS concentration increased the percentage removal of HS. The maximum of 78.88% removal of HS was observed at 27.65 × 10 Nm/s gas flow rate and 48.183 × 10 m/s liquid flow rate for 300 ppm inlet concentration of HS. A model has also been developed to predict the HS gas removal by using the results from the experiments and adding the parameters that affect the scrubber's performance. The deviations between experimental and predicted HS percentage removal values were observed as less than 16%.

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The synthesis gas leaving from the coal gasification process is having particulate matter and other gaseous pollutants majorly hydrogen sulphide and hydrogen chloride (HCl). Wet scrubbers can simultaneously remove the gaseous pollutants and dust particles from effluent gas streams. Dual-flow sieve plate column wet scrubbers can be used for the removal of acid gases from the exhaust gases. A three stage lab scale dual-flow sieve plate scrubber has been designed, fabricated and installed. Experiments were conducted to remove the HCl from the synthesis gas at different gas-liquid ratios within the gas flow rates (Q G ) 8. 3 NaOH solution. A semi empirical model has been developed to predict the efficiency of the HCl scrubbing using the experimental results and the variables which show the impact on the scrubber performance. Almost 80% of the experimental results are matched well with the predicted values with less than ± 15% deviation.

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