Gas purification is one of the important elements of many technologies. One of the methods of gas purification is the use of sorbents. The basis of the developed method is the vibratory introduction of the testing mixture (sorbent in fly ash) into the reaction chamber, which simulates the injection of the sorbent into the flue gas channel. The proposed method and stand enables a reliable comparison of powder sorbents with different rheological properties. A 0.1 % mixture of sorbent in fly ash was used for testing. The contact time can be flow regulated from 0.7-4.9 s. The measurement system enables testing of sorbents using flue gases of various compositions (λ = 1.1–2.7) at various temperatures (105–260 °C). The method was validated according EURACHEM guidelines and successfully tested in laboratory and industrial conditions. After validation the method was used to estimate the effectiveness of several new sorbents designed to remove mercury from flue gases.