Effects of Sodium Carbonate Additive on the Hydroliquefaction of a Sub-bituminous Coal with Fe-Based Catalyst under Mild Conditions

Abstract

In this paper, the influence of Na 2 CO 3 (NC) on the hydroliquefaction performances of Hongliulin (HLL) coal with an Fe-based catalyst, γ-FeOOH (FC), under mild conditions was investigated, and the properties of the resulting preasphaltene and asphaltene were examined. Results show that the addition of NC to FC-catalyzed liquefaction significantly promoted coal conversion and oil production and reduced water production under mild conditions, especially at high initial H 2 pressure. The H 2 consumption of mild liquefaction (0.53−1.93%) is much smaller than that of the traditional liquefaction processes, and the addition of NC to FC can enhance H 2 consumption, especially the runs with weak hydrogen donor solvents. The addition order of NC and FC is an important factor which can affect the activity of FC and NC binary catalysts. There exists a prominent synergistic effect between NC and FC in HLL coal hydroliquefaction, and the synergistic effect could be ascribed to the combined promotion actions of NC for the hydrolyzation of abundant oxygen-containing moieties (such as ether bonds and carbonyl groups) in HLL coal and the depolymerization of macromolecular structures of HLL coal.

Comparative Study of the Catalytic Performances of Na2CO3 and γ-FeOOH in Hydroliquefaction To Propose a Two-Stage Lignite Catalytic Liquefaction Process

“…It can be observed that H 2 consumptions were only 0.28−0.62% at 330−430 °C without catalyst, which was due to the relatively low temperature and pressure under mild liquefaction conditions. 23 Apparently, H 2 consumptions notably increased to 0.59−1.40% in the presence of FO, while it slightly increased to 0.40−0.77% in the presence of NC. These results indicated that H 2 consumptions of XL lignite liquefaction over NC were much lower than that over FO.…”

“…Figure exhibits H 2 consumptions of XL lignite liquefaction over NC and FO. It can be observed that H 2 consumptions were only 0.28–0.62% at 330–430 °C without catalyst, which was due to the relatively low temperature and pressure under mild liquefaction conditions . Apparently, H 2 consumptions notably increased to 0.59–1.40% in the presence of FO, while it slightly increased to 0.40–0.77% in the presence of NC.…”

Effects of sulfur additive on the transformation behaviors of γ‐Fe2O3 and coal liquefaction performances under mild conditions

“…After the completion of liquefaction experiments, the separation of products was as performed as described in our previous works . The gaseous products were analyzed using a gas chromatography (GC 9790‐II, Zhejiang Fu Li Analytical instrument Co., Ltd.) for gas yield calculations.…”

“…Moreover, the addition of effective catalyst under mild liquefaction conditions leads to the more economy of DCL technologies . Up to now, iron‐based catalysts are widely used for most industrial and pilot units of DCL due to its relatively high activity, low cost, and environmental friendliness for disposal.…”

Effect of Carbonization Temperature on the Product Distributions and Characteristics for Integrated Mild Liquefaction and Carbonization of Low-Rank Coals

“…Direct coal liquefaction (DCL) technology, which has been available since the first half of the last century, is regarded as one of the feasible technologies which can realize the efficient conversion of low-rank coals. 6−10 In order to obtain high oil yield and coal conversion, severe liquefaction conditions are generally required that included high temperature (440−470 °C), high pressure (17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30), good hydrogen donor solvent, and effective hydrogenation catalyst for the traditional liquefaction technologies, such as NEDOL, IGOR, and Shenhua technologies. However, the traditional DCL technologies possess the disadvantages of high requirement of installation, high capital and operating cost, and high H 2 consumption due to the severe liquefaction conditions.…”