Tham khảo tài liệu 'heat analysis and thermodynamic effects part 14', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Selective Catalytic Reduction NO by Ammonia Over Ceramic and Active Carbon Based Catalysts 379 Purified gases leaving the electrostatic precipitator section of the power production line are sucked in by a blower and compressed to the pressure corresponding to the conditions in the adsorber. The optimum process temperature 120 oC is set by water injection using compressed air or steam in the column not shown on the drawing upstream the adsorber and in the additional steam exchanger. Gases introduced into a two-stage adsorber flow horizontally through movable bed of active coke and then to the second stage of the process selective reduction of nitrogen oxide with ammonia. On the other hand regenerated coke from the desorber passes through the container situated at the top of the tower first to the second stage of the process of reduction and from there it lowers gravitationally and passes to the first stage. Coke with SO2 adsorbed on it is collected from the first stage at the bottom of the adsorber and is directed to desorber. In this way the movable bed of active coke forms a closed circuit between the adsorber and the regenerating unit. Purified gases leaving the adsorber at a temperature of 120 C are discharged through the flue into the atmosphere. Heat losses due to emission through the adsorber walls and in smoke flues are offset by the heat of reaction. The dew point of the sulphuric acid is not exceeded anywhere along the exhaust gas line to the flue and reheating of the gases is unnecessary. Gases leaving the regeneration system contain approx. 20 of SO2 water vapour carbon dioxide nitrogen HCl and HF and heavy metals. After purification of the gases by means of sorption with the so-called Halex mass the gases are converted to sulphuric acid elemental sulphur or liquid SO2 depending on the variant of the procedure. Chemical mechanism of the process In the Bergbau-Forschung BF process active carbon acts both as an adsorbent and as a catalyst. In the absence .
