Marek Inger

The application of RANS CFD for design of SNCR technology for a pulverized coal-fired boiler

Abstract The article describes the technology of NOx emission abatement by SNCR method. The scope of research included CDF simulations as well as design and construction of the pilot plant and tests of NOx reduction by urea in the plant located in industrial pulverized-coal fired boiler. The key step of research was to determine the appropriate temperature window for the SNCR process. The proposed solution of the location of injection lances in the combustion chamber enabled to achieve over a 30% reduction of NOx. It is possible to achieve higher effectiveness of the proposed SNCR technology and meet the required emission standards via providing prior reduction of NOx to the level of 350 mg/um3 using the primary methods.

On the selection of the best polymorph of Al2O3 carriers for supported cobalt nano-spinel catalysts for N2O abatement: an interplay between preferable surface spreading and damaging active phase–support interaction

A series of cobalt spinel catalysts dispersed over various alumina supports (with varying alpha-, gamma-, delta- and theta-Al2O3 phase contents) were prepared and thoroughly characterized (XRF, XRD, μRS, SEM/TEM/EDX/SAED, TPR) and their reactivity was evaluated in low temperature N2O decomposition as a probe reaction. The observed significant differences in catalytic activities were discussed in terms of the supports nature, active phase dispersion, nanocrystal morphology and the alumina support–Co3O4 interactions. The more reactive amorphous phase as well as the gamma-, delta- and theta-Al2O3 phases gives rise to high dispersion of the spinel nanocrystals (∼10 nm) which is, however, sacrificed by the formation of mixed Co3−xAlxO4 spinels of much less activity. It was revealed that the best support for the deN2O catalyst is an α-Al2O3 phase of micrometric grain size and the optimal size of the Co3O4 nanocrystals is in the range of 20–30 nm. This catalyst was also found to be more resistant to H2O, NO and O2 contaminants in comparison to the catalysts based on γ-Al2O3.

Modernization and Intensification of Nitric Acid Plants

Nitric acid plants both in AZOTY Tarnow and ANWIL SA in Wloclawek are dual pressure plants which means that ammonia oxidation and heat recovery take place under a low pressure whereas absorption under a high pressure. Nevertheless, there are important differences between them in regard to pressure and construction solutions applied and the level of their exploitation. A number of design solutions were implemented which aimed at removal of equipment damage, as well as exchange of machines and equipment and provision of plant continuous operation before 2000. Most of these works were performed by companies themselves, however Fertilizers Research Institute (Instytut Nawozow Sztucznych) participated in realization of some of them. After 2000 the increase of nitric acid plant capacity in the above mentioned Works became necessary. The scope of tasks to be undertaken, the realization of which was necessary to increase plant capacity in the above mentioned Works was to be defined in the first stage. This project was realized in cooperation with Fertilizers Research Institute. Some of the accomplished tasks which allowed for the achievement of stated objectives are presented below.