Kinetic Parameter Calculation and Trickle Bed Reactor Simulation Based on Pilot-Scale Hydrodesulfurization Test of High-Temperature Coal Tar

Abstract

At present, a few chemicals can be separated after further processing of high-temperature coal tar (HTCT) distillates, which have a lower utilization. However, hydrogenation to produce clean fuel oil has not been widely reported in literature. Thus, due to the use of new feedstocks and the implementation of more severe environmental legislations, deep hydrodesulfurization (HDS) of HTCT will face formidable challenges. A series of HDS experiments were performed in a continuous isothermal trickle bed reactor in which the reactor temperature was varied from 648 to 678 K, the pressure from 12 to 16 MPa, and the liquid hourly space velocity (LHSV) from 0.25 to 0.35 h–1, and hydrogen-to-oil ratio kept constant at 2000 L/L. Based on the experimental data, possible reaction pathways of HDS reaction were investigated, and a modified Langmuir–Hinshelwood (LH) HTCT desulfurization kinetic model was established. gPROMS software was used to obtain optimal kinetic parameters that are as follows: EA = 26,842, K 0 = 93,958, α = −1.14, n = 1.65, and m = 0.86. The model can well reproduce various working conditions and has better prediction accuracy. Some characteristics of HTCT HDS reactions were discovered; the reaction order (n) of HTCT HDS is slightly higher than that of crude oil and medium/low-temperature coal tar (M/LTCT), but the activation energy (EA) is relatively smaller. The established reactor model was used to predict the changes of the concentration of hydrogen, hydrogen sulfide, and sulfur compounds in the gas, liquid, and solid phases along the length of the reactor, respectively. The model was also used to predict the effects of pressure, temperature, and LHSV on the conversion rate of sulfur and catalyst effectiveness factors. The results showed that the LHSV has a greater impact on the conversion rate, and the pressure and temperature are less pronounced at high-severity operating conditions; the effectiveness factor is significantly smaller than that of other HDS processes, temperature has a greater effect on the effectiveness factor, followed by pressure and LHSV. The conclusion can provide a basis for further understanding the HTCT hydrotreating process.

Study on the Preparation of Clean Liquid Fuel by Wide Fraction High-Temperature Coal Tar Deep Hydro-Upgrading on a Pilot Plant Trickle Bed Reactor

“…The reduction of S and N at high temperatures can be attributed to several reasons: (1) A higher reaction temperature promotes intermolecular contact, which is beneficial to increase the chemical reaction rate and conducive to the reaction of refractory sulfur-containing and nitrogen-containing compounds with hydrogen . (2) The increase in temperature and the decrease in viscosity accelerate the mass transfer rate between gas–liquid and solid–liquid, which is beneficial to increase the reaction rate of HDS and HDN . (3) Increasing the temperature is conducive to the conversion of macromolecular compounds (gums and asphaltenes) in WHTCT into smaller molecules through mild hydrocracking.…”

“…The kinetic model was included in a isothermal reactor model, − , which was established by using the following assumptions: The reactor operates in isothermal mode. There is no radial concentration gradient in the reactor. The reactor is operated in the steady state. The model is a one-dimensional steady-state model. The phase transition of light components is negligible. …”

“…19 (2) The increase in temperature and the decrease in viscosity accelerate the mass transfer rate between gas–liquid and solid–liquid, which is beneficial to increase the reaction rate of HDS and HDN. 20 (3) Increasing the temperature is conducive to the conversion of macromolecular compounds (gums and asphaltenes) in WHTCT into smaller molecules through mild hydrocracking. These small molecules more easily diffuse into the catalyst pores and reach the internal active sites to react.…”

“…The kinetic model was included in a isothermal reactor model, [16][17][18]20 which was established by using the following assumptions:…”

Molecular-Level Structural Analysis of Hydrotreated and Untreated Atmospheric Residue Oils via Atmospheric Pressure Photoionization Cyclic Ion Mobility Mass Spectrometry and Ultrahigh-Resolution Mass Spectrometry

“…Peaks are distributed among m/z 200−1000 with This increase is in agreement with the well-known reaction pathways of hydrodesulfurization for dibenzothiophene and benzonaphthothiophene. 40,41 The proposed reaction pathways and products of the reactions have been illustrated in Figure S1 of the Supporting Information. The hydrodesulfurization of dibenzothiophene results in cyclohexylbenzene and biphenyl compounds, with DBE values of 5 and 8, respectively (Figure S1a of the Supporting Information).…”