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CEntre for Research &

Technology Hellas (CERTH)

COAL2GAS Final Workshop

Analysis of the Romanian lignite

Craiova, Romania, June 27th 2017

Alexandros Tasianas

Chemical Process &

Energy Resources Institute (CPERI)

1. CERTH received samples from Oltenia coal mine during the 2 drilling

campaigns.

2. The first was carried out in early 2015 and the second one in late 2016 to

early 2017 at the proposed test site in Oltenia, Romania

3. Lab testing of drill samples was carried out in specialised laboratories in

Greece

4. The drill samples that were obtained from the 2nd drilling campaign were

from 5 drill holes, namely CG-01, CG-02, CG-03, CG-04 and CG-06.

5. The testing includes coal characterization and geomechanical tests

performed by CERTH and partners.

Romanian Lignite

Study area location in SW Romania with location of drillholes

Romanian Lignite

A first correlation with

simplified lithologies

from the 5 drill holes

(“coal” means coal

seam)

Featuring the coal seams and the associated surrounding soft rock sediments under investigation in the COAL2GAS project

Romanian Lignite

• Coal laboratory analyses and properties characterization The analyses were carried out on coal seams (V, VII and VIII)

• Geomechanical analysis of Oltenia lignite deposits

We have results for all the coal seams (V, VII and VIII) from all drillholes. The same tests on the surrounding soft rocks were carried out

Oltenia coal characterisation

Core samples concerning the lignite seams V, VII and VIII and surrounding soft rock were ordered, described and prepared for analysis

Methodology

Example from CG-03

Core logging description

carried out by CERTH on

the drillings (rock

samples) from Oltenia

and comparison to the

logs sent by DMT.

The samples received went through a process of coal characterization testing which included the execution of the following:

- Proximate Analysis,

- Ultimate Analysis,

- Sulphur Form Analysis,

- Coal Heating Value,

- Porosimetry Results

Methodology

For the geomechanical analysis of Oltenia lignite deposits the following tests were carried out: • Porosity (n) • Density (ρ) • Bulk density (γ) • Moisture Content (w) • Unconfined compression test:

1. Strength (σci)

2. Strain (ε) 3. Modulus of Elasticity (Εi)

• Poisson ratio (ν) • Shear test:

1. Discontinuous friction angle (φ) 2. Apparent cohesion (c) 3. Residual friction angle (φr)

• Brazilian test (σt)

Methodology

Example description of the determination of porosity and densities for the rock

samples

Methodology

DETERMINATION OF POROSITY / DENSITY

OF ROCK SAMPLE

(E103-84)

BOREHOLE: CG-01

DATE 28/02/2017

SAMPLE ID 170547

SAMPLE S1

DEPTH (m) 36.00 – 36.50

MASS OF SATURATED SPECIMENT (Msat) gr 174.20

BUOYANT MASS (Msub) gr 30.60

MASS OF DRY SPECIMENT (Ms) gr 107.40

SPECIMENT VOLUME V = (Msat-Msub) / Pw (cm3) 143.60

PORES VOLUME Vu = (Msat-Ms) / Pw (cm3) 66.80

POROSITY n = (Vu / V)*100 (%) 46.52

DRY DENSITY Pa = Ms / V (gr/cm3) 0.75

WET DENSITY Psat = (Ms + (Vu*Pw)) / V gr/cm3 1.21

Direct shear test measurements and results

Methodology

Ultimate Analysis (ASTMD 5373-08)

Results- Coal Quality Analysis

Seam VIII Seam VI-VII Seam V Borehole/Sample C

wt%, dry basis H

wt%, dry basis N

wt%, dry basis CG-01/S1 55.86 4.97 1.51 CG-02/S1 59.63 5.11 1.54 CG-02/S2 60.19 6.35 1.42 CG-02/S3 57.14 5.31 1.48 CG-03/S1 61.59 5.90 1.55 CG-03/S2 59.37 6.19 1.31 CG-03/S3 60.78 6.11 1.39 CG-04/S1 47.83 5.48 1.36 CG-04/S2 28.46 2.72 0.90 CG-06/S1 55.00 6.87 1.39

Proximate Analysis (ASTM D3302, D7582)


Seam VIII Seam VI-VII Seam V Borehole/Sample Total Moisture

wt%, as received Inherent Moisture wt%, as received

CG-01/S1 43.47 11.44 CG-02/S1 45.26 16.06 CG-02/S2 45.76 15.67 CG-02/S3 43.45 15.67 CG-03/S1 44.30 12.69 CG-03/S2 38.17 15.67 CG-03/S3 43.93 13.23 CG-04/S1 42.21 13.59 CG-04/S2 35.69 7.20 CG-06/S1 52.50 13.79


Seam VIII Seam VI-VII Seam V Borehole/

Sample Ash

wt%, dry basis Volatile

matter wt%, dry basis

Fixed carbon wt%, dry basis

Volatile matter

wt%, daf

Fixed carbon

wt%, daf

CG-01/S1 15.86 52.77 31.37 62.72 37.28 CG-02/S1 10.93 52.27 36.80 58.68 41.32 CG-02/S2 11.13 53.77 35.10 60.50 39.50 CG-02/S3 16.21 50.03 33.76 59.71 40.29 CG-03/S1 9.00 53.64 37.36 58.95 41.05 CG-03/S2 9.92 52.73 37.35 58.54 41.46 CG-03/S3 10.51 55.28 34.21 36.88 38.23 CG-04/S1 32.63 42.04 25.33 62.40 37.60 CG-04/S2 52.73 32.36 14.19 68.46 31.54 CG-06/S1 18.62 51.47 29.91 63.25 36.75

Proximate Analysis (ASTM D3302, D7582)

Sulphur Form Analysis


Seam VIII Seam VI-VII Seam V Borehole/Sample S

wt%, as received

CG-01/S1 1.92 CG-02/S1 1.18 CG-02/S2 1.73 CG-02/S3 2.47 CG-03/S1 1.24 CG-03/S2 0.99 CG-03/S3 1.35 CG-04/S1 1.11 CG-04/S2 2.84 CG-06/S1 3.70

Coal Heating Value (the coal samples tested are classified as “lignite B”

in the coal grade classification)


Seam VIII Seam VI-VII Seam V Borehole/Sample Higher heating value

wt%, as received

Lower heating value wt%, as received

kcal/kg kJ/kg (kcal/kg) kJ/kg

CG-01/S1 3028.8 12680.9 2630.4 11012.9 CG-02/S1 3038.6 12722.0 2630.4 11012.9 CG-02/S2 3070.4 12855.1 2626.6 10997.0 CG-02/S3 3044.9 12748.3 2637.1 11041.0 CG-03/S1 3206.3 13424.1 2778.9 11634.6 CG-03/S2 3450.2 14445.2 3030.8 12689.3 CG-03/S3 3239.3 13562.3 2807.0 11752.3 CG-04/S1 2469.6 10339.7 2061.4 8630.6 CG-04/S2 1718.2 7193.7 1419.6 5943.5 CG-06/S1 2482.6 10394.1 2009.4 8412.9

Surface area measurements obtained through the application of BET

and BJH methods to the seams VIII, VI-VII and V

Results- Porosimetry

Surface Area (m2/g) Seam VIII Seam VI-VII Seam V

Borehole/Sample BET BJH Adsorption cumulative surface area of pores between 1.000 Å

and 3000.000 Å width

BJH Desorption cumulative surface

area of pores between 1.000 Å and 3000.000 Å width

CG-01/S1 1.2596 2.2714 2.3865 CG-02/S1 0.9136 1.7177 1.7705 CG-02/S2 0.7812 1.4768 1.5221 CG-02/S3 1.0220 1.8685 1.9452 CG-03/S1 0.8181 1.5716 1.6503 CG-03/S2 1.0541 1.9165 2.0037 CG-03/S3 0.7432 1.3970 1.5041 CG-04/S1 2.3675 4.1455 4.3365 CG-04/S2 8.4142 14.3344 16.6948 CG-06/S1 0.9837 1.7925 1.9076

Pore volume measurements obtained through the application of BET

and BJH methods


Pore Volume (cm3/g) Seam VIII Seam VI-VII Seam V

Borehole/Sample BET BJH Adsorption cumulative volume of

pores between 1.000 Å and 3000.000 Å width

BJH Desorption cumulative volume of

pores between 1.000 Å and 3000.000 Å width


Pore size measurements obtained through the application of BET and

BJH methods


Pore Size (Å) Seam VIII Seam VI-VII Seam V

Borehole/Sample BET Adsorption average pore width (4V/A)

BJH Adsorption average pore width (4V/A)

BJH Desorption average pore width (4V/A)


N2 adsorption and desorption isotherms of

the studied coals at 77.3 K for coal seam V

Recapitulative table of results of laboratory rock mechanics testing in coals

Results- Geomechanical tests

UNCONFINED SHEAR TEST

COMPRESSION TEST

BO

REH

OLE

SAM

PLE

SPEC

IMEN

DEP

TH

DES

CR

IPT

ION

PO

RO

SITY

DEN

SITY

BU

LK D

ENSI

TY

MO

ISTU

RE

CO

NTE

NT

STR

ESS

STR

AIN

MO

DU

LUS

OF

ELA

STIC

ITY

PO

ISSO

N R

AT

IO

AN

GLE

OF

DIS

CO

NT.

FR

ICT

φ

AP

PA

REN

T

CO

HES

ION

c

RES

IDU

AL

SHEA

R

STR

ENG

HT

φ

BR

AZI

LIA

N T

EST

m % gr/cm3 kN/m3 % Mpa % 0 Mpa 0 Mpa

CG-1 S1 1 36.00-36.50 COAL 46.52 0.75 12.1 61.4 41 0.28 34

CG-2 S1 1 38.78-39.1 COAL 54.41 0.68 12.3 78.3 7.62 5.74 604.00 0.37 1.57

CG-2 S2 1 67.27-67.67 COAL 54.69 0.68 12.2 79.6 7.36 4.85 858.00 0.36 1.31

CG-2 S3 1 109.15-109.55 COAL 55.41 0.72 12.8 6.57 4.97 691.00 0.38 18 0.22 16

CG-3 S1 1 34.90-35.32 COAL 52.50 0.70 12.3 74.2 11.97 6.31 963.00 0.36 43 0.22 32 1.70

CG-3 S2 1 67.11- 67.56 COAL 50.14 0.75 12.5 66.6 6.45 5.26 667.00 0.34 42 0.21 26 1.49

CG-3 S3 1 106.40-106.80 COAL 53.77 0.70 12.4 75.1 11.91 7.32 808.00 0.34 0.78

CG-4 S1 1 38.35-39.01 COAL 59.43 0.62 12.2 93.7 7.01 4.96 981.00 0.35 37 0.37 21 1.05

CG-4 S2 1 69.37-69.70 COAL 55.32 0.69 12.4 7.26 6.77 1219.00 0.37 44 0.19 20

CG-6 S1 1 35.10-35.50 COAL 45.01 0.78 12.3 56.6 7.37 3.34 1092.00 0.36 1.95

Analytical results of laboratory tests on the lignites of Seam V

Borehole

Sample

Depth

Porosity

(n)

Bulk

Density

(γ)

Moisture

Content

(w)

Strength

(σci)

Modulus of

Elasticity

(Εi)

Poisson

Ratio

(ν)

Residual friction

angle

(φr)

Brazilian

Test

(σt)

Unit (m) KN/m3 % Mpa Mpa Mpa

CG-2 S3

109.15-

109.55 0.5541 12.8 6.57 691 0.38 16

CG-3 S3

106.40-

106.80 0.5377 12.4 75.1 11.91 808 0.34 0.78

Average 0.5459 12.6 75.1 9.24 749.5 0.36 16 0.78


Recapitulative table of results of laboratory rock mechanics testing on the

clay samples


BOREHOLE SAMPLE SPECIMEN

DEPTH

DESCRIPTION As DESCRIPTION the

name of the Group according to ASTM from the grain size

classification of the sample using the ASTMUSCS

system is used and not the description (according to the borehole logs) of the layer where

the specimen was taken from:

BULK DENSITY

MO

ISTU

RE

CO

NTE

NT

WET

γw

et

DR

Y γ

dry

m kNm3 kNm3 %

CG-1 S2 1 34.70-35.00 CLAY 21.0 18.1 17.8

CG-2 S4 1 37.00-37.30 CLAY 18.0 13.4 31.6

CG-2 S5 1 42.13-42.43 CLAY 18.7 16.5 15.4

CG-2 S6 1 106.25-106.59 CLAY 21.3 18.2 21.5

CG-2 S7 1 115.15-115.50 CLAY 19.9 16.1 22.4

CG-3 S4 1 62.50-62.96 CLAY 20.4 18.7 21.5

CG-3 S5 1 69.56-70.00 CLAY 20.4 16.7 25.8

CG-3 S6 1 101.95-102.40 CLAY 21.0 18.0 15.9

CG-3 S7 1 108.70-109.00 CLAY 21.0 17.7 17.5

CG-4 S3 1 41.57-41.90 CLAY 20.8 17.8 18.7

CG-4 S4 1 67.40-67.84 CLAY 19.8 15.9 25.1

CG-4 S5 1 72.60-72.79 CLAY 21.0 17.6 20.5

CG-6 S2 1 34.11-34.55 CLAY 20.5 17.2 27.8

CG-6 S3 1 39.65-39.95 CLAY 21.3 18.4 18.0

Conclusions

The coal has significant moisture content of over 40% in most cases

tested

The carbon content exceeds 60%wt (on a dry basis)

The ash content of the coals ranges from 9% to 19%

The Sulphur content ranges from 1% to 3.7%, which corresponds to

typical and expected values for coal

The volatile matter, in wt% (daf), ranges from 36.88-68.46% and the

fixed carbon, also in wt% (daf), ranges from 31.54-41.46%

Conclusions

The coal has a Higher Calorific Value, calculated in the range

between 7193 and 14445 KJ/Kg (as received basis) which falls inside

the lignite B coal grade

The pore size ranges between 29 and 37 nm, which classifies the

Oltenia coal samples as macroporous materials

The BET Specific Surface Area of the samples range from 0.74 m2/g to

1.26 m2/g, with some higher extremes in certain drillholes that can

be explained due to the more clayey composition of the lignite

sample

The N2 isotherm indicates a monolayer formation with a slight

hysteresis on the desorption plot

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