Lumped kinetic simulation of hydrodenitrogenation for full‐range middle‐low temperature coal tar

Abstract

With the increasingly prominent environmental problems and depletion of light petrochemical resources, the clean utilization of heavy oil has become the research focal area. The hydrodenitrogenation (HDN) experiments and kinetics of full‐range middle‐low temperature coal tar (MLCT) was studied on a fixed‐bed reactor with a Ni‐Mo/γ‐Al2O3 catalyst. Two kinds of three‐lumped kinetic models (K1 and K1.24) based on different reaction orders and high‐middle‐low reactivities were established and fitted by a simulated annealing algorithm for coal tar HDN reactions. The results presented good correspondence with experimental data following an average relative error of less than 0.3%. The effect of temperature, pressure, and liquid hourly space velocity (LHSV) on HDN of different reactivity nitrogen compounds (NCs) of MLCT was studied using the lumped kinetic models. Also, the difference between K1 and K1.24 models on the embodiment ability for HDN laws was also discussed from multiple perspectives. It has been observed that the HDN reactions of low and middle reactivity NCs are more influenced by LHSV; high temperature and pressure are more critical for the removal of low reactivity NCs, and low‐temperature or ‐pressure zone have larger effects on coal tar HDN reactions, especially at high LHSV; temperature has much more influence than pressure on the HDN effect, particularly towards the low reactivity NCs. The results of HDN laws for high reactivity NCs are concordant with K1 and K1.24 models. The K1.24 model is a bit more reasonable to reveal the HDN law of middle to low reactivity NCs.

Kinetic Models of Deep Hydrotreating Reactions to Produce Ultralow Sulfur Diesel

“…Some examples of the alternative sources of diesel fuel precursor streams are MDSO, middle-low temperature coal tars (MLCT), heavy gas oils from oil sands bitumen (HGOSB), VGO, LCO, and CGO. It has been observed that these types of feedstocks tend to have a higher content of heterocyclic N-containing compounds, aromatics, and asphaltenes compared with conventional middle distillates such as SRGO, resulting in the need for more severe operating conditions, more HDN active catalyst, and better kinetic models. − For these reasons, the kinetics of ultradeep HDT reactions of heterocyclic N-containing compounds has attracted greater interest in several research groups in recent years, leading to the development of better and more detailed kinetic models for HDN, HDA, HDO, etc.…”