Development of an Online Soft Analyzer for the Continuous Analysis of BTEX Emissions from the Furnace of Sulfur Recovery Units

The oxidation of Benzene, Toluene, Ethylbenzene, and Xylenes (BTEX) in the furnace of SRUs at high temperature is an effective solution to prevent Claus catalyst deactivation in the downstream catalytic converters. However, the existing SRUs do not have the means to monitor BTEX emissions from Claus furnace due to lack of commercial online analyzers in the market. This often leads to excessive temperatures up to 1150 °C in the furnace to ensure BTEX destruction. Such high temperatures increase fuel gas consumption and CO emission and reduce sulfur recovery efficiency. To obtain continuous BTEX indication at the furnace exit, an online BTEX soft sensor model is developed to predict BTEX concentration at furnace exit. Subsequently, this soft sensor will be implemented in one of the SRUs of ADNOC Gas Processing. The BTEX soft sensor has been developed by constructing a compact kinetic model for aromatics destruction in the furnace based on the understanding of BTEX oxidation mechanisms derived using a detailed and well validated kinetic model developed previously. The kinetic model, including its rate parameters were incorporated into Hysys/Sulsim software, where both the reaction furnace and catalytic converters were simulated. The BTEX soft sensor has been validated with plant data from different ADNOC Gas Processing SRU trains under a wide range of feed conditions (particularly, with varying relative concentrations of H2S, CO2, and hydrocarbons in acid gas feed) in order to ensure its robustness and versatile predictive accuracy. The model predicts BTEX emissions from the reaction furnace under a wide range of operating conditions in the furnace with deviation not exceeding +/- 5 ppm. It also predicts the reaction furnace temperature (with a deviation of +/- 5%) and species composition from the furnace exit within a reasonable error margin. Presently, the model is in the process of being deployed in one of the SRUs of ADNO Gas Processing as an online soft sensor, where it can read the feed conditions, predict the BTEX exit concentration and write this value to the DCS. Thus, plant operators can monitor BTEX exit concentration on continuous basis and use it as a reliable basis to lower fuel gas co-firing rate in the furnace to achieve optimum furnace temperature that provide efficient BTEX destruction and low CO emission. The online soft analyzer, when deployed in SRU, will continuously predict BTEX emission from SRU furnace with high accuracy, which cannot be done experimentally in the plant or reliably using most of the existing commercial software. This approach can be used to seek favorable means of optimizing BTEX destruction to enhance sulfur recovery, while decreasing fuel gas consumption and carbon footprint in sulfur recovery units to reduce operating cost.

XRF and powder X-ray diffraction analysis of ancient iron slags from the “Sladak Kladenets” and “Malko Dryanovo” archaeological sites, Bulgaria

Using X-ray fluorescence and Powder X-ray diffraction analysis, the chemical and phase composition of ancient iron slags and raw iron ore were investigated. The type of raw ore was identified as self-fluxing. The operating furnace temperature was determined in the range 900–1000 °C. The results obtained are of archaeological importance. They will contribute to the chronological specification of the time of realization of the metallurgical process and the type of used furnaces.

Resistência ao impacto de revestimentos para fundições odontológicas, em diversas condições de temperatura no forno

The impact strenght of four dental casting investments is investigated as a function of heat loss after removal of tu a furnace temperature of 700ºC, at different time intervals. Attention is called to the fact hat a graphical relationship between temperature loss and lmpact strenght, even hough obtained from averages of 10 experiments, but without a statistical analysls, may induce to erroneous conclusions.

Perda de temperatura em revestimentos odontológicos, após sua remoção do forno

The time elepsed between the removal from the furnace of a castin cylinder and the casting proper, depends on the knowledge and ability of the operator. The heat loss, after removal of a furnace temperature of 700ºC at different time intervals, was mensured in four dental casting investiments, using different volumes of investment, with or without the protection of a casting ring and with or without asbestos liner. The results, presented in the form of tables and graphs, tell us about the importance of this additional technical detail, in the dental casting operation. Temperature losses in the order of from 100º to 200ºC were verified, already two minutes after removal from the furnace.

Modeling analysis and optimization of temperature curve of welding furnace

Reflux welding is widely used in SMT (surface patch technology) During this production process, the quality of the product is essential to maintain the temperature and the furnace speed required by the process. The furnace temperature curve in the furnace is an important form of reaction welding process. In order to improve the process efficiency of the return furnace, the heating welding process model is established based on the Fourier heat conduction law,1 D heat conduction model and Newton cooling law and draws the furnace temperature curve model. Then, the upper boundary of the conveyor speed using the boundary analysis and multiple target planning, and further explore the research and optimization direction of subsequent process flow. At the same time, this paper examines and analyzes the modeling process and results, and effectively demonstrates the scientific nature and accuracy of the model. Finally, the paper analyzes the significance of the above model and research in chip processing.

Study on Fire Resistance of Floor Structures in High-speed Train

According to the standard EN 45545, fire resistant tests of floor structures in high-speed train were carried out. Two typical floor structures which were placed in the passenger train were tested. Integrity and insulation are main performance criteria to evaluate fire resistance of floor structures. The furnace temperature is in accordance with the requirements in the standard ISO 834. The surface temperature and deflection were recorded with time. Glass wool and aluminium corrugated sandwich structure in two structures were burned through. The experiments were terminated at 30 minutes and 31 minutes respectively for the two structures. A large amount of smoke and the sound of cracking of the exposed surface of the test piece were produced, although the unexposed surface of test pieces did not reach the failure condition.

Study of internal porous structure formation of the powder metallurgically prepared aluminium foam

The internal pore wall structure formation and density play an important role in improving the mechanical and thermal properties of the closed-cell aluminium foams. The present research work aims to investigate the internal structure formation of the aluminium foam prepared by powder metallurgy and the uniformity of the distribution of the pores when the minimum amount of TiH2 is added. The foamable precursor of two different aluminium alloys (Al-1050 and A5083) is produced with a TiH2 gaseous agent of 0.05 wt.%. The parameters analysed include the density, pore wall formations, pore, and metal density distribution inside the structure with the help of X-ray tomography. Furthermore, the image-processing technique has been adopted to produce the 3D surrogate model of the foam for visual inspection and analysis. The obtained results show the importance of the amount of TiH2 addition and of the foaming furnace temperature in deciding the internal porous structure formation. Further, the pore morphology of lower porosity foams (in the range of 30-40 % porosity) of the two alloys produced at 690 °C furnace temperature is investigated with the help of developed surrogate models. The presence of micropores and uniformity of the distribution of pores found brings the idea of choosing the optimized structure of foam for thermal energy storage systems associated with PCM.