Experimental Study

Turkey has huge lignite deposits although most of them are of low quality. The total reserve of Can lignite is 79,000,000 tonnes (Kahriman et al., 2000). The proximate analysis results of Can lignite are given in Table 21.1.

Table 21.1 Proximate analyses (%) of Can lignite.

Fixed carbon

64.81

Volatile matter

28.08

Sulfur

3.80

Ash

7.11

Moisture

10.70

Calorific value

22,402 kJ/kg

H2O2 solution was chosen as an oxidative medium for decreasing sulfur and mineral matter of Can lignite. At the beginning, the sample was ground, sieved to pass 0.250 ^m. It was stirred with 50 ml H2O2 of 5% for 20 minutes. Then, that sample was washed with distilled water and dried in the autoclave at 105°C. Later, it was treated with 50 ml aquatic acidic solutions of HNO3, HCl, H2SO4, H3PO4, HCOOH, and HF of 5% for 20 minutes, separately. The solution was filtered through the blue ribbon filter and dried in the autoclave at 105°C. The sulfur and ash analyses of these demineralized samples were done according to ASTM standards (ASTM, 1983).

As seen from Table 21.1, the sulfur ratio of Can lignite is too high. In order to utilize this natural source, some pretreatments were applied for. For this purpose, some acidic solutions were chosen for decreasing sulfur and mineral parts of lignite treated after 5% H2O2 solution. The total sulfur results of demineralized Can lignite are given in Table 21.2.

Table 21.2 Total sulfur % values of Can lignite and other 5% chemical-treated samples.

Sample

5% H2O2

Decrease in sulfur amount

Sulfur removal %

Can (A)

3.56

0.24

6.32

(A)+HNO3

3.46

0.34

8.95

(AHH3PO4

3.08

0.72

18.95

(A)+H2SO4

3.06

0.74

19.47

(A)+HCOOH

2.94

0.86

22.63

(A)+HF

2.83

0.97

25.53

(A)+HCl

2.43

1.37

36.05

The calculations are shown below. Decrease in sulfur amount was determined as follows: 3.80-3.56% = 0.24%; Sulfur removal % was determined as follows: 0.24/3.80x100= 6.32%.

Table 21.3 shows the mineral matter ratios of Can lignite and chemical-treated samples according to the leaching process which was applied to them.

Table 21.3 Ash and demineralization variation % of Can lignite and 5% chemical-treated samples.

Sample

5% H2O2

Ash reduction %

Demineralization %

Can (A)

5.98

1.13

15.89

(A)+H3PO4

5.03

2.08

29.35

(A)+HCOOH

4.70

2.41

30.89

(A)+HNO3

4.70

2.41

33.89

(A)+HCl

4.64

2.47

34.74

(A)+H2SO4

3.99

3.12

43.88

(A)+HF

3.69

3.42

48.10

The calculations are done as follows: 7.11-5.98% = 1.13% 1.13/7.11x100 = 15.89%

The calorific values were determined with IKA C4000 bomb calorimeter. The variation in calorific values of Can lignite after applying for those chemicals to original lignite and chemical-treated samples is given in Table 21.4. The calorific values are high heating values. Those variations of calorific values were found at the following: (24 106.9-22 401.6)/22 401.6= 7.61%. The calorific value was increased after H2O2 plus HCl application as 7.61%.

Table 21.4 Calorific values of Can lignite and 5% chemical-treated samples.

Sample

5% H2O2 kJ/kg

Variation in calorific value %

Can (A)

22 401.6

-

(A)+HF

22 273.9

(-) 0.57

(A)+HCl

24 106.9

(+) 7.61

(A)+HNO3

24 163.3

(+) 7.86

(a)+h2so4

24 281.9

(+) 8.39

(A)+HCOOH

24 280.2

(+) 8.39

(A)+H3PO4

24 374.3

(+) 8.81

Fig. 21.1 FTIR spectrum of Can lignite treated after 5% H2O2 solution (X scale wave number cm 1 and Y scale transmittance % ).

FTIR spectrum was taken with Perkin-Elmer spectrometer for observing the leaching process effects. Figure 21.1 shows the FTIR spectrum of Can lignite treated with 50 ml, 5% H2O2 as follows:_

Wave numbers (cm 1)

Bond properties

1095

C—O stretching

1435

C=C and C=O groups

2921

Aliphatic C—H groups

3392

Aliphatic C—H groups

Figure 21.2 shows the FTIR spectrum of Can lignite treated with 5% H2O2 plus 5% H2SO4 solutions. The peaks were originated because of those defined groups.

Figure 21.2 shows the FTIR spectrum of Can lignite treated with 5% H2O2 plus 5% H2SO4 solutions. The peaks were originated because of those defined groups.

H2o2 Spektrum
Fig. 21.2 FTIR spectrum of Can lignite treated with 5% H2O2 and later 5% H2SO4 solutions

Wave numbers (cm 1)

Bond properties

536

Mineral matter

1031

C—O stretching

1095

C—O stretching

1401

Asymmetric symmetric carboxyl groups

1611

Asymmetric symmetric carboxyl groups

2922

Aliphatic C—H groups

3385

Aliphatic C—H groups

Figure 21.3 shows the FTIR spectrum of Can lignite treated with 5% H2O2, later 5% HF solutions. Those peaks belong to these groups in the body.

Figure 21.4 shows the X-ray spectrum of original Can lignite. X-ray spectra were taken with Rigaku-X-ray spectrometer between 20 (0-70°)

The peaks at 2© = 23.962, 33.162, 40.858, 43.436, 49.498, 54.158, 62.522 show hematite (Fe2O3) groups in the body. The peaks seen at 2© = 24.521, 31.338, 38.582, 52.352, 57.717 are due to anhydride (CaSO4) groups. Figures 21.5 and 21.6 show the X-ray spectrums of Can lignite treated with 5% H2O2 solution and 5% H2O2 plus H2SO4 solutions, respectively.

Fig. 21.3 FTIR spectrum of Can lignite treated with 5% H2O2 plus 5% HF solutions with

Wave numbers (cm 1)

Bond properties

710

Mineral matter

1275

C—O stretching

1607

Asymmetric symmetric carboxyl groups

2921

Aliphatic C—H groups

3176

Aliphatic C—H groups

The peaks seen in Figure 21.5 at 2© = 20.781, 31.025, 31.871, 36.606 and 2© = 24.179, 33.218, 40.935, 49.500, 62.577, 64.056 are due to anhydride and hematite groups, respectively.

Figure 21.6 shows the X-ray spectrum of Can lignite treated with 5% H2O2 and later 5% H2SO4 solutions. The peaks shown at 2© = 20.882, 26.661, 39.517, 40.438, 42.556, 45.837, 50.194, 59.998, 64.201, 67.877, 68.342, 75.654 and 2© = 24.184, 33.181, 35.682, 40.960, 43.537, 49.557, 54.178, 57.701, 62.514 are quartz (SiO2) and hematite (Fe2O3) groups left in the body at the end of the experiment.

Figure 21.7 shows the X-ray spectrum of Can Lignite treated with 5% H2O2 and later 5% HF solutions. Quartz and hematite groups give peaks at 2© = 20.839, 26.640, 39.518, 60.104, 67.718 and 2© = 22.953, 25.422, 31.375, 38.660, 40.839, 48.796, 49.220, 52.298, respectively.

Fig. 21.4 X-ray spectrum of Can lignite.
Fig. 21.5 X-ray spectrum of Can lignite treated with 5% H2O2 solution.

Was this article helpful?

0 0
Guide to Alternative Fuels

Guide to Alternative Fuels

Your Alternative Fuel Solution for Saving Money, Reducing Oil Dependency, and Helping the Planet. Ethanol is an alternative to gasoline. The use of ethanol has been demonstrated to reduce greenhouse emissions slightly as compared to gasoline. Through this ebook, you are going to learn what you will need to know why choosing an alternative fuel may benefit you and your future.

Get My Free Ebook


Post a comment