A mechanistic simulation of direct coal liquefaction was developed which utilizes the technique of Monte Carlo simulation for both: (1) the creation of a molecular coal structure and (2) modelling of its subsequent pyrolysis under liquefaction conditions. ... Investigators have studied model reactivi- ties of coal by exploiting the advantages ...
Direct coal liquefaction could become a viable option for the production of transportation fuels in Asian countries with cheap and abundant low-rank coals. ... exhibited good adsorption and stabilization performance advantages for As in soils. The effect of limonite addition on the performance of Li
Background Indirect coal liquefaction differs fundamentally from direct coal liquefaction in that the coal is first converted to a synthesis gas (a mixture of H2 and CO) which is then converted over a catalyst to the final product. Figure 27-9 presents a simplified process flow diagram for a typical indirect coal liquefaction process.
In direct coal liquefaction, finely divided coal is mixed with a solvent and heated under pressure in a hydrogen atmosphere and in the presence of a catalyst. After separation from ash and unconverted coal, the resulting liquids are usually further refined to produce finished products. Indirect liquefaction is a two-step process.
The U.S. Department of Energy (DOE) had an active coal liquefaction research program in 1970 into the 1980s in response to the Organization of the Petroleum Exporting …
The use of high-carbon-based feeds to produce alternative fuels and value-added chemicals is discussed. Basic conversion chemistry, chemical structures of coal and lignin biomass are discussed, followed by process technologies for direct liquefaction, liquid quality, process control and modeling, advantages and limitations, and future trends.
The lessons learned from the direct coal liquefaction work have been summarized as being technically feasible but the process for producing synthetic crudes …
The U.S. Department of Energy (DOE) had an active coal liquefaction research program in 1970 into the 1980s in response to the Organization of the Petroleum Exporting Countries (OPEC) oil embargo of 1973, but the funding has been greatly reduced since the 1990s when the DOE development for direct coal liquefaction ended.
Direct coal liquefaction (DCL) converts solid coal (H/C ratio ≈ 0.8) to liquid fuels (H/C ratio ≈ 2) by adding hydrogen at high temperature and pressures in the presence or absence of catalyst. This review provides a comprehensive literature survey of the coal structure, chemistry and catalysis involved in direct liquefaction of coal. ...
The CLR from a pilot plant for direct liquefaction of Shenhua coal in China was used as the carbon precursor. It was a thermoplastic carbon matrix with a softening point of about 193 °C, crushed and sieved to be particle of 150–250 μm before use.The proximate and ultimate analyses (Table 1), ash compositions (Table 2) and …
The direct liquefaction process (Fig. 3) employs a coal ground to a fine powder, solvent, hydrogen, and catalyst employed at elevated pressures (1000–2500 psig) and temperatures (400–450°C).The solvent mixed with the coal forms a pumpable paste. Intimate contact between solid coal and solvent is easier to achieve than that between coal and gaseous …
The direct liquefaction experiments show that the best results came from the Shenhua Group, ranging from $15 to $18 per barrel 5 (see below for a detailed account of Shenhua). The indirect coal liquefaction project from Shanxi has made great progress in reducing the cost of catalyst so as to reduce the total cost.
The growing demand for petroleum, accompanied by the declining petroleum reserves and the concerns over energy security, has intensified the interest in direct …
This study is devoted to demonstrating experimentally the advantages of direct coal liquefaction residue (DCLR) on improving the slurry ability of lignite through co-slurry and microwave co-pyrolysis. The results show that: as the lignite/DCLR mass ratio decreased from 10:0–5:5 the maximum solid concentration (MSC) of the mixed slurry ...
Brown coal liquefaction technology is intended realize the liquefaction of brown coal of Victoria, Australia, with the object of utilizing it as an energy resource. Research and Development was started in 1981 with a 50 t/d pilot plant in Victoria province. Fig. 4.68 shows the process. The initial goals of the project, 50% liquid fuel yield (actual result …
The process involves gasification of coal, which in turn will produce synthetic gas (a mix of CO+H2). The synthetic gas can be liquefied to its fuel equivalent in presence of cobalt/iron-based catalysts at higher pressure and temperature. However, liquefied coal emits twice as much CO2 as burning oil. It also emits a large volume of SO2.
A coal hydrogenation and liquefaction process in which particulate coal feed is pressurized to an intermediate pressure of at least 500 psig and slurried with CO.sub.2 liquid to provide a flowable ...
Waste coal-derived isotropic pitch was produced via a direct coal liquefaction (DCL) process [[12], [13], [14]] in tetralin (1,2,3,4-tetrahydronaphthalene), followed by pressure filtration and distillation of the resultant coal extract to render an isotropic pitch.DCL of coal in tetralin (1:3 by weight) was carried out in a 2 L autoclave …
The effective utilization of the coal liquefaction residue (CLR), which contains about 80% organic matter, is of great significancefor improving the oil yield of the direct liquefaction process ...
The key advantages of this process over the well-known direct liquefaction processes (Bergius, NEDOL, H-Coal, SRC-II, EDS, Shenhua process, etc.) are that the addition of a catalyst and a large ...
Direct coal liquefaction (DCL) converts solid coal (H/C ratio ≈ 0.8) to liquid fuels (H/C ratio ≈ 2) by adding hydrogen at high temperature and pressures in the presence or absence of catalyst. This review provides a comprehensive literature survey of the coal structure, chemistry and catalysis involved in direct liquefaction of coal. This ...
Direct coal liquefaction in the system containing water and syngas or CO (DCLS) is an economical and effective method that can convert low-rank coals into fuels and value-added chemicals in the ...
Schematic of Direct Coal Liquefaction. Air enters the system and goes through air separation. This produces N2 and O2. ... Some advantages of using this process for biomass: 1) it is possible to …
Many direct coal liquefaction processes have been shown to be technically viable in plants processing up to 150–250 t/day. The thermal efficiency of conversion has proved to be high (~65%) showing a considerable advantage over gasification synthesis routes. Laboratory tests have shown that the distillates produced can be used as substitutes ...
The growing demand for petroleum, accompanied by the declining petroleum reserves and the concerns over energy security, has intensified the interest in direct …
Liquefaction can be direct, from the coal itself, or indirect, from synthesis gas (CO and H 2) obtained by gasification of the coal. Coal liquefaction incorporates both an increase in the H/C ratio and removal of heteroatoms (S, N, O) and inorganic oxides (ash). ... Sometimes there are advantages to processing coal simultaneously with other ...
Direct coal liquefaction has long been recognized as a competition between hydrogenation to liquid products and destructive distillation that forms solids (Bergius, 1926). The former reaction represents the goal, whereas the latter leads us to consider the application of petrologic methods to help explain diminished productivity. 6.2.
This direct coal liquefaction process has been piloted by the American Exxon Company at its Baytown Refinery in Texas (Exxon EDS, 1981). The stages of the process are shown in Fig. 4.66.Coal is slurried with hydrogenated recycle oil. The coal-oil slurry is passed via …
Direct liquefaction processes add hydrogen to the hydrogen deficient organic structure of the coal, breaking it down only as far as is necessary to produce distillable liquids. Coal …
