A Study on the Hydrotreating of Coal Hydroliquefaction Residue and its Kinetics

Abstract

Hydro-conversion of coal hydroliquefaction residue obtained from a 6t/day pilot plant of Shenhua Group in Shanghai was carried out under the hydrotreating condition. The coal hydroliquefaction residue and its product were extracted in sequence with n-hexane, toluene and tetrahydrofuran in a Soxhlet apparatus. The n-hexane soluble fractions increased with the increase of reaction temperature and time. Its amount increased from 14.14% to a maximum of 40.86% under the conditions of 470 °C and 30 min, which meant that moderate extension of coal residence time in the coal hydroliquefaction reactor is beneficial to the increase of oil yield. A 4-lumped kinetic model of coal hydroliquefaction residue hydro-conversion was performed using solubility-based lumped fractions. In the model, the tetrahydrofuran insoluble fractions were classified into two parts: easily reactive part and unreactive part. The kinetic parameters were estimated by a fourth-order Runge-Kutta method and a nonlinear least squares method, and the apparent activation energies were calculated according to the Arrhenius Equation. A large quantity of total catalyst consisting of remained liquefaction catalyst, part of the mineral from raw coal and additive Fe-based catalyst could considerably reduce the apparent activation energy of hydro-conversion for the toluene insoluble/tetrahydrofuran insoluble fractions to 36.79 kJ•mol -1 . The calculated values of the model coincided well with the experimental values.

Detailed Description of Coal Tar Hydrogenation Process Using the Kinetic Lumping Approach

“…The model is based on the difficulty of cracking, in which residues are classified as lumps that are either "easy" or "difficult" to crack, reflecting basically the residual hydrocracking reaction. Huang 19 proposed the hydrotreatment of coal hydroliquefaction residue and its kinetics, in which a four-lumped kinetic model was established using solubility-based lumped fractions. The hydro-conversion behavior of CHLR was studied under moderate hydrotreatment conditions to determine the possibilities and advantages of using recycled CHLR as a coreactant in CHL.…”

New kinetic model of coal tar hydrogenation process via carbon number component approach

“…Theoretically, the required kinetic model should consider all the elementary reactions occurring during hydrogenation [7], but practical application is impossible because of the complexity of the reaction mixture consisting of numerous components. Thus, existing modeling technologies of hydrogenation are primarily based on the lumped method [8][9][10][11][12][13][14][15][16], in which the complex mixture is usually divided into smaller groups of pseudo components with respect to their properties, such as boiling point, and http://dx.doi.org/10.1016/j.apenergy.2014. 10.009 0306-2619/Ó 2014 Elsevier Ltd. All rights reserved.…”

Catalytic Hydroliquefaction of Sapropels

“…Hydroliquefaction is carried out in the presence of a solvent, molecular H 2 , and a catalyst at 350-450°C and 1-10 MPa [5][6][7][8][9][10][11][12][13]. It is thought that naphthenoaromatic hydrocarbons are the best solvents considering their H-donor capability [14][15][16][17][18].…”