RECENT ADVANCES IN DIREECT COAL LIQUEFACTION

Presented by:

Muhammad Naqi Shah

Roll No: CH-22/2010-2011

RECENT ADVANCES IN DIREECT COAL LIQUEFACTION

Presentation includesIntroductionCoal & its ClassificationInfluencing factors for DCLEffects of coal pre-treatment on DCLMulti-stage DCL processDCL catalystConclusion

INTRODUCTION

Importance of coal liquefactionRapid increase in petroleum demand

Declining reserves of petroleum oils

Processes of coal liquefactionIndirect Coal Liquefaction (ICL)

Direct Coal Liquefaction (DCL)

Direct Coal Liquefaction (DCL)

coal+solvent+catalyst+hydrogen gas

450-500 C under 15-30 MPa

Table.1 Summary of major DCL process developed around the world

CountryProcess

Reactor Catalyst

Capacity (t/d) Year

SRC-I Coal slurry dissolver — 6 1974

SRC-II Coal slurry dissolver — 50/25 1974-1981

USA

EDS Entrained bed Ni/Moc 250 1979-1983

H-Coal Fluidized bed Co-Mo/Al2O3 600 1979-1982

CTSL Fluidized bed Ni/Mo 2 1985-1992

HTI Suspended bed GelCatTM 3 1990s

IGOR Fixed bed

Red- muda,

200 1981-1987b

Germany Ni-Mo/Al2O3

PYROSOL Counter-current — 6 1977-1988

BCL Fixed bedb

Fe-baseda,

50 1986-1990b

Japan Ni-Mo/Al2O3

NEDOL Fluidized bed Nature pyrite 150 1996-1998

UK LSE

Stirred tank-typea,

— 2.5 1983-1995

fluidized bedb

USSR CT-5 — Mo 7 1986-1990

China

Shenhua I Suspended bed Fe-based 6 2002-

Shenhua II Suspended bed Fe-based 3,000 2004-

a First-stage; b Second-stage; c Recycled solvent catalytic hydrogenation

Table.2 . The operating parameters and

experiment results of some major DCL processes.

Process HTI IGOR NEDOL Shenhua

Coal Shenhua Xianfeng lignite Shenhua Shenhua

Temperature ( °C) 440~450 470 465 455

Pressure (MPa) 17 30 18 19

Space velocity (t/m3/h) 0.24 0.60 0.36 0.70

Conversion (%,daf coal) 93.5 97.5 89.7 91.7

C4+oils (%, daf coal) 67.2 58.6 52.8 61.4

Residues (%, daf coal)a 13.4 11.7 28.1 14.7

Hydrogen consumption (% daf coal) 8.7 11.2 6.1 5.5

a Including ash, spent catalyst and un-converted coal

COAL AND ITS CLASSIFICATION

Rank of the coalPeat lignite sub-bituminous anthracite bituminous

Constitutes of coalI. Fixed carbon

II. volatile carbon

III. other constitutes

COAL LIQUEFACTION CATALYSIS

Self catalysis Mineral present in coal (pyrite)

Catalyst usedHeterogeneous catalyst are used so that, separation product from catalyst is simple

Porous structure of catalyst

INFLUENCING FACTORS FOR DCL

Temperature: Cracking of coal at elevated temperature Enhance free radical formation Enhance free radical reaction Influencing temperature range is 350-

800 C

Solvent: To stabilize the free radicals by donating

hydrogen Promote the cracking of coal macromolecules

Continued…

Facilitate the heat and mass transfer for coal liquefaction reaction

Classification : specific, non-specific, degrading, reactive

Used solvent: tetra line, tetrahydrofluoranthene (4HFL)

Continued..

Pressure & atmosphere High pressure beneficial as: keep the

solvent and products in liquid phase prevent coke build up on reactor wall and catalyst surface

Range 15-30 MPa Preferred atmospheric are nitrogen (N2)

and hydrogen (H2)

EFFECTS OF COAL PRE-TREATMENT ON DCL

Swelling treatment Enhance coal priority Improve the dispersion of catalyst onto the coal

structure Pre-swollen in tetra line for 4 hr at temperature

from room temp to 160 C

Thermal & hydro-thermal treatment Thermal treatment under drying in not

beneficial Thermal treatment under vacuum and steam is

beneficial

Continued…

Treatment in hot compressed water (hydro-thermal) is also beneficial

Multistage DCL process Multigas (mostly two stages) process is

beneficial Higher conversion and higher oil yield 15 MPa, 10 wt% Fe-10 wt% Ni 380 C for 15 min in 1st stage 450 C for 105 min in 2nd stage

DCL CATALYST

Catalyst typesIron based, Co, Mo, Rn etc

Loading amount, the preparation method, dispersion state, solvents, coal-containing minerals

CONCLUSION

Overall, although many commercialized processes have been developed in the U.S, Europe, Japan and china, the optimization of the operating conditions for these DCL processes is still the focus for many studies

In addition to the common Fe based catalyst, Mo,Co and Ru as well as SO42-/MxOy, solid acids were also demonstrated effective for DCL