Hydrogen per oxide was used with acetic acid and formic acid as a mixture with different ratios because this acid have strong abilities to oxidize the variety of compounds and it have 47% active oxygen in it (Tabinda et al., 2018). Gaseous emissions from the treated samples at different concentrations (15, 20, 25%) at different temperatures (40, 45, 50ᵒC) with different ratios for acetic and formic acid (1:1, 1:2, 2:1) compared with untreated TPO and diesel oil (Table 1).The results showed the reduction in the gaseous emissions (SOx, NOx, CO and CO2) after the process of desulphurization. All reaction treatments showed less gaseous emissions except for 20% nitric acid but these emissions did not exceeds from the emissions of crude TPO. CO2 removed completely for some conditions but some for not due to the combustion process. Among all the reaction conditions acetic acid showed best results for the removal of SOx, NOx and CO2 from the crude TPO and best results observed at 1:2 ratio with 20% concentration at 45ᵒC. Increase in the emissions of O2 observed after the treatments. TPO often contain 1.65-4% sulphur in it (Han et al., 2018). Sulfur is the crosslinking agent added to the pyrolysis process (Quek & Balasubramanian, 2013). SOx and NOx emissions are three times higher in TPO 350 and 309 respectively as compared to the diesel fuel (Williams et al., 1998; Han et al., 2018). Tabinda et al stated that desulphurization reduce the sulphur content from 4–0.2% and reduction in the sulphur content reduced the SOx emissions up to 96% (Tabinda et al., 2018). Formic acid and H2O2 shows the best reduction in the emissions at 2:1 ratio with 25% conc. at 45ᵒC. Sulphuric acid treatment shows best results at 40ᵒC with 25% con. same for nitric acid treatment except for concentration that is 20%. The effective treatment of Crude TPO stated in the Table 1.
Treatments
|
Parameters
|
Table 1
Emissions from diesel, crude TPO and treated TPO samples
Ratios
|
Temp.
(ᵒC)
|
Conc.
(%)
|
SOX
(ppm)
|
NOx
(ppm)
|
CO
(ppm)
|
CO2
(ppm)
|
O2
(%)
|
Viscosity
(cSt)
|
Diesel oil
|
3
|
120
|
201
|
2.98
|
14.2
|
2.13
|
Crude Tyre Pyrolysis Oil (TPO)
|
350
|
309
|
1502
|
4.56
|
18.7
|
1.58
|
CH3COOH/H2O2 mixture treatments
|
1:1
|
40
|
15
|
45
|
60
|
420
|
Nil
|
19.3
|
8.57
|
20
|
34
|
101
|
310
|
Nil
|
19
|
3.02
|
25
|
38
|
90
|
290
|
Nil
|
19.5
|
6.41
|
45
|
15
|
55
|
110
|
510
|
Nil
|
18.2
|
2.92
|
20
|
60
|
53
|
470
|
Nil
|
18.5
|
3.54
|
25
|
45
|
75
|
260
|
Nil
|
18.0
|
6.89
|
50
|
15
|
40
|
89
|
312
|
Nil
|
18.9
|
2.93
|
20
|
47
|
30
|
600
|
Nil
|
18.7
|
24.07
|
25
|
50
|
204
|
540
|
Nil
|
19.2
|
3.44
|
1:2
|
40
|
15
|
25
|
210
|
110
|
Nil
|
19.8
|
24.79
|
20
|
2
|
14
|
121
|
Nil
|
19.2
|
33.28
|
25
|
31
|
69
|
678
|
Nil
|
19.5
|
5.22
|
45
|
15
|
34
|
12
|
270
|
Nil
|
19.0
|
42.53
|
20
|
2
|
4
|
78
|
Nil
|
20.1
|
4.26
|
25
|
15
|
80
|
120
|
Nil
|
20.5
|
8.82
|
50
|
15
|
30
|
130
|
150
|
Nil
|
19.8
|
54.01
|
20
|
34
|
210
|
210
|
Nil
|
19.5
|
4.21
|
25
|
32
|
114
|
123
|
Nil
|
19.2
|
10.16
|
2:1
|
40
|
15
|
50
|
88
|
759
|
Nil
|
18.4
|
7.096
|
20
|
38
|
103
|
166
|
Nil
|
18.6
|
2.19
|
25
|
45
|
240
|
199
|
Nil
|
19.2
|
6.43
|
45
|
15
|
35
|
212
|
249
|
Nil
|
20.1
|
2.76
|
20
|
33
|
50
|
100
|
Nil
|
19.5
|
3.75
|
25
|
31
|
14
|
212
|
Nil
|
18.9
|
3.45
|
50
|
15
|
45
|
79
|
496
|
Nil
|
19.2
|
18.489
|
20
|
35
|
90
|
213
|
Nil
|
18.5
|
6.635
|
25
|
34
|
65
|
227
|
Nil
|
19.2
|
3.79
|
CHOOH/H2O2 mixture treatments
|
1:1
|
40
|
15
|
101
|
210
|
1192
|
Nil
|
14.5
|
8.77
|
20
|
108
|
120
|
2056
|
1
|
13.6
|
5.21
|
25
|
85
|
140
|
1204
|
Nil
|
13.8
|
7.804
|
45
|
15
|
145
|
170
|
2031
|
1
|
13.5
|
4.16
|
20
|
130
|
230
|
1840
|
Nil
|
13.9
|
13.24
|
25
|
102
|
345
|
1400
|
Nil
|
14.2
|
5.71
|
50
|
15
|
75
|
201
|
850
|
Nil
|
15.6
|
4.41
|
20
|
125
|
256
|
730
|
Nil
|
19.5
|
14.98
|
25
|
115
|
111
|
1524
|
1
|
21.7
|
4.82
|
1:2
|
40
|
15
|
75
|
35
|
267
|
Nil
|
20.2
|
65.85
|
20
|
45
|
210
|
980
|
Nil
|
19.5
|
46.42
|
25
|
60
|
130
|
1202
|
Nil
|
19.2
|
23.37
|
45
|
15
|
105
|
267
|
890
|
Nil
|
21.2
|
38.88
|
20
|
59
|
153
|
245
|
Nil
|
20.5
|
48.94
|
25
|
76
|
206
|
456
|
Nil
|
19.8
|
16.18
|
50
|
15
|
110
|
56
|
520
|
Nil
|
19.5
|
87.65
|
20
|
101
|
37
|
620
|
1
|
18.2
|
78.21
|
25
|
120
|
340
|
240
|
Nil
|
18.0
|
68.61
|
2:1
|
40
|
15
|
67
|
99.19
|
178
|
Nil
|
17.5
|
5.12
|
20
|
68
|
93.95
|
262
|
Nil
|
18.2
|
10.17
|
25
|
39
|
91.23
|
282
|
1
|
16.4
|
2.55
|
45
|
15
|
42
|
93.17
|
215
|
1
|
11.1
|
11.11
|
20
|
62
|
87.64
|
452
|
Nil
|
12.5
|
3.25
|
25
|
1
|
87.48
|
258
|
Nil
|
13.7
|
4.29
|
50
|
15
|
66
|
97.83
|
342
|
Nil
|
17.8
|
17.11
|
20
|
68
|
97.35
|
259
|
Nil
|
18.5
|
3.13
|
25
|
2
|
90
|
243
|
0.26
|
19.5
|
5.32
|
8%H2SO4 treatments
|
8%
|
40
|
15
|
35
|
101
|
530
|
0.45
|
19.2
|
2.87
|
20
|
32
|
70
|
240
|
0.24
|
18.6
|
4.74
|
25
|
20
|
21
|
199
|
0.69
|
19.5
|
2.51
|
45
|
15
|
60
|
180
|
600
|
0.33
|
19.4
|
7.14
|
20
|
45
|
150
|
340
|
0.56
|
17.5
|
2.61
|
25
|
75
|
26
|
364
|
0.33
|
19.5
|
4.22
|
50
|
15
|
205
|
83
|
340
|
0.66
|
16.3
|
2.17
|
20
|
250
|
350
|
760
|
0.54
|
17.2
|
5.82
|
25
|
230
|
280
|
680
|
0.32
|
18.3
|
2.63
|
20%HNO3 treatments
|
20%
|
40
|
15
|
95
|
375
|
1208
|
1
|
19.2
|
2.09
|
20
|
80
|
230
|
413
|
1
|
18.5
|
4.42
|
25
|
85
|
350
|
1001
|
1
|
19
|
2.52
|
45
|
15
|
150
|
200
|
900
|
1
|
17.6
|
4.57
|
20
|
122
|
100
|
850
|
1
|
18.2
|
1.96
|
25
|
101
|
48
|
597
|
1
|
17
|
2.79
|
50
|
15
|
160
|
210
|
1400
|
1
|
17.5
|
4.68
|
20
|
145
|
108
|
1574
|
1
|
17.6
|
2.59
|
25
|
180
|
184
|
1634
|
1
|
17
|
6.16
|
Table.2. Percentage removal of SOx and NOx in treatments using acid mixtures and acids
Sr. no
|
Treatment
|
Ratio
|
Percentage reduction in SOx (%)
|
Percentage reduction in NOx (%)
|
1
|
Acetic acid/ H2O2 with 20% at 45ºC
|
1:2
|
99.42
|
98.71
|
2
|
Formic Acid/ H2O2 with 25% at 45ºC
|
2:1
|
99.71
|
71.69
|
3
|
8% H2SO4 with 25% at 40ºC
|
-
|
94.28
|
93.20
|
4
|
20% HNO3 with 20% at 40ºC
|
-
|
77.14
|
25.71
|
NOx = Nitrogen oxides; SOx = Sulphuric Oxides.
Table.3. Calorific values of treated samples with least gaseous emissions
Treated Samples
|
Ratios
|
Temperature (ºC)
|
Concentration (%)
|
Calorific value (MJ/Kg)
|
Diesel
|
-
|
Room Temperature
|
-
|
44.5
|
Pyrolysis oil
|
-
|
Room Temperature
|
-
|
43.50
|
Acetic acid + H2O2
|
1:1
|
40
|
20
|
42.90
|
1:2
|
45
|
20
|
41.10
|
2:1
|
45
|
25
|
42.60
|
Formic acid + H2O2
|
1:1
|
50
|
15
|
42.40
|
1:2
|
40
|
20
|
43.30
|
2:1
|
45
|
25
|
40.40
|
8% H2SO4
|
-
|
40
|
25
|
43.20
|
20% HNO3
|
-
|
40
|
25
|
43.40
|
Table.4. Energy cost analysis of tyre pyrolysis oil
Type of cost
|
Unit
|
Tyre oil
|
Total capital cost
|
Rs
|
16.051466 million
|
Capital cost
|
Rs/Day
|
2229.37
|
Expenses
|
Operation expenses
|
Rs/Day
|
500
|
Feed stock expenses
|
Rs/Day
|
0.4 million
|
Maintenance expenses
|
Rs/Day
|
1500
|
Labor expenses
|
Rs/Day
|
3000-4000
|
Taxes
|
Rs/Day
|
1209.35
|
Total expenses
|
Rs/Day
|
0.41043 million
|
Profit
|
Rs/Day
|
55000-65000
|
Total production
|
Rs/Day
|
0.468million
|
Oil production
|
liter/Day
|
6000-7000
|
Production cost
|
Rs/liter
|
35-45
|
Rs = Rupees.
Oxidative desulphurization:
Desulfurization effects the emissions of SOx, NOx, and CO after the treatment with different conc. at different temperature. According to Liu et al the with the increase in the conc. of H2O2 emissions of SOx decrease and the extraction of the sulfur through solvent extraction is increase (Liu et al., 2017). Emissions of the gasses decrease with the increase of concentrations (Fig. 1, 2, 3 &4). Sulfur present in the crude TPO converted into the SO3 and SO2 and emitted through exhaust. SO2 doesn’t influence the emissions of other gasses (Rang et al., 2006 ; ). Emissions of SOx, NOx and CO decrease at all concentration but the most effective conc. are 20 and 25% at 40 and 45 ºC that means these conc. and temperature treatments effect the desulfurization in best manner to reduce the SOx emissions after combustion.
Reduction in the SOx emissions is due to the conversion of compounds into less hazardous compounds and absorption into the solvent to remove these compounds from the TPO (Kozak & Merkisz, 2005 ; Hossain et al., 2019). Treatments which are effectively reduced the SOx emission can also be effective to reduce the NOx emissions. Some treatments show higher emission of NOx due to the fuel bond nitrogen (FBN). NOx emissions are affected by air/fuel ratio as the higher air/fuel ratio decrease the emissions. While the FBN increase the emissions of NOx. Ignition delay also contribute in the larger emission of NOx (Vihar et al., 2015). Emissions of CO is increased at low temperature due to the incomplete burning. Time and Air are the most important factors as the insufficient time and air unable to oxidize the CO into CO2 (Arpa & Yumrutas, 2010 ; Bhaskar et al., 2022)
This study revealed that the most efficient and effective treatment with respect to the desulfurization and reduction of the SOx and NOx emissions was the 20% acetic acid with 45ºC temperature (table 2). Pyrolysis process removed the sulphur content from the TPO upto 83.75% and further removal in the sulphur content is achieved with the oxidative desulphurization. The more powerful oxidizing agents are also more corrosive and reactive like peroxy acids. The reaction mixture formed from the formic acid/H2O2 and acetic acid/H2O2. Peroxy acids are polar compounds so they have ability to separate the layer formed after the reaction. For H2O2 Martin et al. stated that it was a strong oxidizing agent having 47% of mass unit active oxygen (2010). Advantage of using H2O2 as oxidizing agent is that the reaction proceeds at very mild conditions and no surplus heating required. It can oxidize the variety of organic compounds (Arpa & Yumrutas, 2010 ; Fu et al., 2022).
Viscosity:
Viscosity of the treated sample has vast ranges in case of formic acid and acetic acid sulfuric acid and nitric acid treatments. Table 1 represents the all treated samples values for all the treatments. Diesel oil viscosity ranges up to 2-6cSt (Aydın & İlkılıç, 2012). As the sample treated with acetic acid/H2O2 fall within the range as the diesel. At 40ºC with 20% concentration viscosity is 2.19cSt while at 45ºC with 15% conc. for 2:1 ratio while the highest value is 42.53cSt at 45ºC with 15% conc. for 1:2 ratio. The lowest value of viscosity in formic/H2O2 treatment is 2.55cSt at 40ºC with 25% conc. for 2:1 ratio while the highest value in the treatment are incredibly high for the 1:2 ratio. Viscosity of the 8% H2SO4 treatments is fall within the range of diesel. The lowest value of viscosity at 50ºC with 15% concentration that is 2.17cSt and for nitric acid minimum value of viscosity is at 45ºC with 20% conc. is 1.96cSt that is less than the diesel lowest value (2cSt).
Decrease in the viscosity is due to the increased amount of CH3COOH in the mixture. Formation of larger molecule due to the heating can contribute in the high viscosity of the fuel (Hossain & Davies, 2013 ; Perez et al., 2022). Increase in the amount of viscosity is due to the poor settling of the suspended particles in the sample that is result in form of sludge separation. Lower viscosity is better for the efficient engine performance and have efficient mixing of air/fuel ratio. Decrease in the viscosity is due to the removal of aromatic compounds from the fuel (Ahmad et al., 2016 ; Liu and Zhang, 2022). As viscosity not affect the emissions of SOx, NOx, and CO in the samples but it affect the efficiency of the engine when it is use in comparison with diesel. Viscosity of the fuel can be lower by pre-heating before entering the fuel in the engine (Miteva et al., 2016).
Calorific values:
The calorific value of crude TPO (43.50MJ/kg) is excellent as compared to the values of diesel (44.5MJ/kg) that it shows that the oil have almost equal extent to diesel to produce energy (Singh et al., 2019).
Table 3 represents the calorific values for the conditions where less SOx emissions observed. For the acetic acid/H2O2 treatment calorific value is highest for 2:1 at 45ºC with 25% conc. This highest value is lower than the calorific value of crude TPO. Formic acid/H2O2 treatment is show highest value for 1:2 at 40ºC with 20% concentration but this value is also lower than the crude TPO. 8% H2SO4 treatment calorific value is consider insignificant because it have very low difference from crude TPO while the 20% HNO3 shows the highest calorific values among all the treatments.
From the above calorific values we can stated that the SOx emissions affect them. As the increase in Sulfur removal from the fuel decreases the calorific values of the treated samples and where the Sulfur removal is not significant the calorific values of the samples are high and insignificant. This relationship of SOx emissions and calorific value help us to analyze that desulfurization effects the calorific values of the treated samples (Aydın & İlkılıç, 2012 ; Zhong et al., 2022). NOx emission does not affect the calorific values as the emissions of SOx. Change in calorific values in sequence with NOx emissions is not considerable. However the process of desulfurization affects the calorific values as the calorific values in all treated samples decrease than the crude TPO (Quek & Balasubramanian, 2013 ; Teoh et al., 2022). So we can conclude that the desulfurization lower the calorific value of TPO.
Energy cost analysis:
Fuel cost analysis is performed for the cost analysis under financial expenses and benefits during the production of the product. Cost analysis is not affected by the output of the products.
Figure shows the expenses and benefits on the pyrolysis plant. The ratio of profit is far higher as compared to operational cost of project. It has not only economical but also its one of sustainable practice. It not only served as an opportunity but also serves as an option to get rid of solid waste. All that needed is capacity building, governmental supervision and private enterprisers and interest groups to serve the purpose.
Recent sale price of the diesel in markets is 113.24Rs/liter. Price of diesel is much higher than the price of crude TPO as it have sold in market at 45-55Rs/liter. From the above economic analysis we can state that the crude TPO is more economical than the diesel and furnace oil. Price of pyrolysis oil is 85% less than the price of diesel oil (Wongkhorsub & Chindaprasert, 2013 ; Damiri, 2022).
Pyrolysis process produces different products and by-products such as oil, carbon black and methane gas. These products useful in the different industries as the TPO is used in industry in place of furnace oil, carbon black in shoe industry and methane gas used to generate the energy in pyrolysis process. Pyrolysis process have some unusual by products such as carbon credit and energy. These carbon credits are claimed by the company after certification in the governmental certifying agency (Neto et al., 2019).