“An improved waste substance-based composition useful as catalyst for pyrolysis and the method thereof”

Abstract

Disclosed is a waste substance-based composition useful as catalyst for pyrolysis of a biomass including a combination of steel slag and sewage sludge char in which the ratio of steel slag and sewage sludge char is 1:1 by weight. Also provided is a method of manufacturing the composition.

Specification

Description:FIELD OF THE INVENTION
This invention relates to a catalyst for pyrolysis. More particularly, the present invention is related to an improved waste substance-based composition useful as catalyst for pyrolysis and the method of manufacturing the composition in which the improvement lies on the quality of the resultant/end product (bio-oil/gas) i.e. the product with more desirable compound and less undesirable compound.
BACKGROUND ART
The pyrolysis is a process of thermal decomposition of a material such as biomass in anaerobic condition converting the biomass into a bio-oil and bio-gas. The pyrolysis reaction is enhanced by the presence of catalyst such as metal-modified zeolites catalyst, molybdenum-based catalyst (TK-261, TK-341) which is used in the industry. These catalysts are the costlier (goes up to $3000 per ton) in view of manufacturing process, chemicals, equipment required and the labour.
In the field of pyrolysis, environmental/pollution and oleophobic issue (i.e. the oil/gas not in a homogeneous phase) are the factors in determining the quality of the end product (bio-oil/bio-gas). Compound containing nitrogen and oxygen is responsible for environmental and oleophobic problem respectively. On the other hand, compound containing carbon and hydrogen enhance the quality of bio-oil/gas. Therefore, what is required is that the end product including more number of compounds containing hydrogen and carbon atom for instance hydrocarbon, & less number of compounds containing nitrogen and oxygen atom for example volatile organic compounds (VOCs) or polyaromatic hydrocarbons (PAHs), furan & its derivative, amines, nitrates, nitriles, ether, carboxylic acids.
Keeping in the view of cost, there are few existing art which teaches the catalysts made out of the waste substance, for instance steel slag (herein after referred as to "SS") is a waste byproduct in steel making process, is used as catalyst for pyrolysis process [(Sangyoon Lee et al, Use of steel slag as a catalyst in CO2-cofeeding pyrolysis of pine sawdust, Journal of Hazardous Materials 392 (2020) 122275)]. However, it is not suggested in this prior art as to how to use SS for achieving more number of desirable compounds (containing hydrogen & carbon) and less number of undesirable compound, rather, in this prior art, the bio-oil/bio-gas as produced by the use of SS containing nitrogen and oxygen based compoundwhich are vinyl acetate, glycolaldehyde, acetic acid, 1-hydroxy-2-propanone, 2-hydroxyethyl acetate, butanedial, 2-furfural, 1-(acetyloxy)-2-propanone, 2-furanmethanol, 2(5 H)-furanone, methacrolein, phenol, 2-methoxy-phenol, 3-methyl-phenol, 2-methoxy-4-methylphenol, dihydro-4-hydroxy-2(3 H)-furanone, 4-ethyl-2-methoxy-phenol, 1-hydroxy-3,6-dioxadicyclo [3.2.1] octan-2-one, 2-methoxy-4-vinylphenol, 1,4:3,6-dianhydro-alpha-d-glucopyranose, 2-hydroxymethyl-5-furfural, 2-methoxy-4-(1-propenyl)-phenol, D-allose.
Another waste-based substance is sewage sludge that is a waste product from wastewater treatment contains organic matter, nutrients, and contaminants like heavy metals and pathogens can be used as a fertilizer or soil improver. The sewage sludge can be converted into solid material through various process including pyrolysis and this solid material is known as sewage sludge char. In existing art, few literatures are reported comparing catalytic effect standard catalyst and activated char (activated through various activating material NaOH, KOH, ZnCl2, H2SO4). Ali Zaker et al, 2021 [Ali Zaker et al, Catalytic pyrolysis of sewage sludge with HZSM5 and sludge-derived activated char: A comparative study using TGA-MS and artificial neural networks, Journal of Environmental Chemical Engineering 9 (2021) 105891] teaches the comparative catalytic effect of HZSM5 (zeolite catalyst) and sludge derived activated char (herein after referred to as "AC"). Another research article by Ali Zaker and Zhi Chen, 2021[Ali Zaker and Zhi Chen, Catalytic Pyrolysis of Sewage Sludge for Upgrading Bio-Oil Quality Using Sludge-Based Activated Char as an Alternative to HZSM5, World Academy of Science, Engineering and Technology, International Journal of Environmental and Ecological Engineering, Vol:15, No:8, 2021] teaches catalytic pyrolysis of sewage sludge for upgrading bio-oil quality using sludge-based activated char as an alternative to HZSM5. These documents suggest activated char not sewage sludge char (i.e. without activation) as catalyst for pyrolysis. Also, surface area of sewage sludge (without activation) of the prior art is very low (69.63m2/g) therefore won't be useful in pyrolysis process. As per the teaching of Ali Zaker et al, 2021is production of AC from sewage sludge may generate toxic gases into the environment which is not desired. Ali Zaker et al, 2021 further suggests that the investigations on the as analysis of evolved gaseous during the activation process is recommended prior to the use of sewage sludge-based AC as a catalyst. Further, Ali Zaker and Zhi Chen, 2021 teaches bio-oil containing oxygen-containing compounds such as 2-heptadecanone, aromatic compounds, organicacids (e.g., butanoic acid, heptanoic acid, pentanoic acid. Feedstock sensitivity might be another limitation for this prior art.
In order to obviate aforementioned drawbacks and to meet the aforementioned needs, the present inventors suggest an improved catalyst for pyrolysis in which the improvement lies on the quality of the resultant/end product (bio-oil/gas) i.e. the product with more number of desirable compound (containing carbon and hydrogen) and less number of undesirable compound (containing oxygen and nitrogen) which is achieved by a special combination of steel slag (hereinafter referred to as "SS") and sewage sludge char (hereinafter referred to as "SSC" by the present inventor.
OBJECT OF THE INVENTION:
It is an object of the invention is to overcome the aforesaid drawbacks and to achieve the aforesaid needs.
It is another object of the invention is to provide an improved waste substance-based composition useful as a catalyst for pyrolysis of a biomass.
It is yet another object of the invention is to provide a catalyst which results the bio-oil/bio-gas with more desirable compounds (containing carbon and hydrogen) and less undesirable compounds (containing oxygen and nitrogen).
It is yet another object of the invention is to provide a catalyst where SSC is used as such i.e. not activated.
It is yet another object of the invention is to provide a catalyst which is not only economic but also is equilibrium with standard/industrial catalyst.
It is yet another object of the invention is to provide a waste substance-based catalyst which is not feedstock sensitive.
It is further object of the invention is to provide a process for preparing the composition.
SUMMARY OF THE INVENTION:
According to one aspect there is provided a waste substance-based composition useful as catalyst for pyrolysis of a biomass, said composition including a combination of steel slag and sewage sludge char. The present invention yields bio-oil/gas with more desirable compounds (containing carbon & hydrogen) and less undesirable compounds (containing nitrogen and oxygen).
In an embodiment, the SSC is not activated.
In an embodiment, the ratio of SS and SSC is 1:1 by weight.
In an embodiment, the sewage sludge char (SSC) includes fixed carbon of 70%.
In an embodiment, the surface area of SSC is 400 m2/g.
In an embodiment, ash content of SSC is 30-50% and volatilities is 20%.
In an embodiment, the particle size of SS is 0.074-0.15mm while the same is 0.5-1mm for SSC.
According to another aspect there is a provided a process for preparing the composition comprising the steps of

i) preparing steel slag product (SS) by obtaining the SS and washing the same with ionised water and subjecting the product for air drying for 24 hours to remove presence of any impurities like dust, dirt etc followed by oven drying for 2 hours at a temperature of 105°C to remove complete moisture followed by calcination at 800°C for 4 hours;
ii) preparing sewage sludge char product (SSC) by obtaining the raw sewage sludge and then subjecting for air drying for 24 hours at room temperature followed by heating at 250°C at a rate of 5°C per minute in an inert atmosphere till it reaches up to 700°C and holding the product at 700°C for 3 hours;
iii) mixing the product of step (i) and step (ii).

In accordance with these and other objects which will become apparent hereinafter, the instant invention will now be described with particular reference to the accompanying drawing.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 is the reference diagram of TMR-GC/MS by which the instant composition is analysed;
Figure 2 illustrates the comparative study of instant composition (steel slag and sewage sludge char 1:1) and standard/industrial catalyst (TK-341) in accordance with the present invention;

Figure 3 illustrates the comparative study of the catalyst containing instant ratio (i.e. steel slag : sewage sludge char 1:1) and other ratio (steel slag : sewage sludge char 7:3) in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION
In the present invention, whatever the instrument including tandem micro-reactor-gas chromatography/mass Spectrometry (TMR-GC/MS) manufactured by Frontier Laboratories, Coupled Plasma Optical Emission Spectroscopy (ICP-OES) and other instrument, is used for the purpose of analysis/characterization of instant composition. The Applicant(s) doesn't claim protection for these instruments. The Applicant(s) need protection for the claimed composition and the process of preparing such composition only.
In the existing art, metal-modified zeolites catalyst, molybdenum-based catalyst (TK-261, TK-341), is used for the pyrolysis. These catalysts are not only costly but also hazardous. In existing art, SS and SSC individually used as catalyst but they are failed to achieve the desired effect i.e. bio-oil/bio-gas compounds containing more desirable compounds (containing carbon and hydrogen) and less undesirable compounds (containing nitrogen and oxygen).
The present invention provides a composition including a special combination of SS and SSC which results bio-oil/bio-gas with more number of desirable compounds (containing carbon and hydrogen) and less number of undesirable compounds (containing nitrogen and oxygen).
In an embodiment of the invention, the ratio of steel slag and sewage sludge char is 1:1 by weight. The desired result won't be achieved if SS and SSC is used beyond this ratio.
The present invention is also distinct in view of SSC as used. In present invention SSC is not activated.
In an embodiment of the invention, the SSC includes fixed carbon. In an embodiment, the amount of fixed carbon of SSC is 70%.
In an embodiment of the invention, the surface area of SSC is 400 m2/g.
In an embodiment, ash content of SSC is 30-50% and volatilities is 20%
In an embodiment of the invention, the particle size of SS is 0.074-0.15mm while the same is 0.5-1mm for SSC.
The present invention also provides a process for preparing the aforesaid composition comprising the steps of
i) preparing steel slag product (SS) by obtaining the SS and washing the same with ionised water and subjecting the product for air drying for 24 hours to remove presence of any impurities like dust, dirt etc followed by oven drying for 2 hours at a temperature of 105°C to remove complete moisture followed by calcination at 800°C for 4 hours;
ii) preparing sewage sludge char product (SSC) by obtaining the raw sewage sludge and then subjecting for air drying for 24 hours at room temperature followed by heating at 250°C at a rate of 5°C per minute in an inert atmosphere till it reaches up to 700°C and holding the product at 700°C for 3 hours;
iii) mixing the product of step (i) and step (ii).
In an embodiment, the biomass is selected from a group consisting of wood waste, pine sawdust or a combination thereof.

The present invention is now illustrated by the way of non-limiting examples:

EAMPLE 1:
Materials: SS was obtained from local mill, Nagpur, Maharashtra and sewage sludge was obtained from sewage treatment plant, Bhandewadi, Nagpur, Maharashtra, which was then converted to sewage sludge char (SSC).
In an embodiment, SS and SSC was combined in a ratio of 1:1 and was exemplified as Formula A as herein below:
Formula A:
i. SS: 0.025g
ii. SSC: 0.025 g
Method:
SS as above obtained was washed with the ionised water and was then subjected for air drying for 24 hours to remove impurities like dust, dirt etc followed by oven drying for 2 hours at a temperature of 105°C to remove moisture followed by calcination at 800°C for 4 hours in order to get the SS product. On the other hand, sewage sludge as above obtained was subjected for air drying at room temperature for 24 hours to dewatering 90% sewage sludge and reduce moisture content. The product thus obtained was heated in a tube furnace at 250°C at a rate of 5°C per minute in an inert atmosphere in order to reach 700°C and holding the product at 700°C for 3 hours.
In another embodiment, SS and SSC was combined in a ratio of 7:3 and was exemplified as Formula B as herein below:
Formula B:
i. SS: 0.0175g
ii. SSC: 0.0075g
The composition of Formula B was prepared as per the method as stated in Formula A except the ratio of SS and SSC.
In an embodiment, TK-341 was used as standard catalyst.
Evaluation:
1. Element analysis:
Coupled Plasma Optical Emission Spectroscopy (ICP-OES) was used for analysing various elements & their concentration and the results are herein below:
Table 1: Element of the instant composition
Element in Steel Slag Metal Content Element in
Sewage Sludge Char Metal Content
Ca 30.6(wt%) Ag 4.1(ppm)
Fe 24.1(wt%) Al 3.52(wt%)
Mg 4.9(wt%) As 7.2(ppm)
Mn 1.9(wt%) B 44.9(ppm)
Si 1.9(wt%) Ba 256.0(ppm)
Al 1.9(wt%) Be 0.7(ppm)
P 0.59(wt%) Bi 13.2(ppm)
Ti 0.59(wt%) Ca 3.4(wt%)
V 0.50(wt%) Cd 0.8(ppm)
Na 0.42(wt%) Ce 16.6(ppm)
K 0.20(wt%) Cr 39.5(ppm)
Cr 0.18(wt%) Cu 336.4(ppm)
B 219(ppm) Er 0.9(ppm)
Ba 205.0(ppm) Fe 1.81(wt%)
Ga 177 (ppm) Gd 4.5(ppm)
Sr 169.5(ppm) Hf 1.2(ppm)
Pb 147.5(ppm) Hg 0.8(ppm)
Sn 30.5(ppm) K 0.39(wt%)
Zr 22.0(ppm) La 22.2(ppm)
Sb 17.5(ppm) Li 5.9(ppm)
Cu 14 (ppm) Lu 0.3(ppm)
Zn 14 (ppm) Mg 0.57(wt%)
Bi 11.5(ppm) Mn 216.2(ppm)
Ce 5.5(ppm) Mo 4.9(ppm)
Lu 4.0(ppm) Na 0.17(wt%)
Mo 4.0(ppm) P 0.48(wt%)
Li 3.0(ppm) S 20(ppm)
Y 3 (ppm) Si 1.1(wt%)
Ni 2.5(ppm) Pb 0.35(ppm)
Er Er(ppm) Zn 2.6(ppm)


ii. Comparative quality assessment of Formula A, Formula B and TK-341:
Preparation of biomass sample:
The wood waste and pine sawdust sample were collected from local saw-mill which were washed with de-ionised water to remove the impurities. The biomass was crushed using a hammer mill and sieved to get the particle size of 0.18-0.4mm, and was then air dried at 105°C for a day in a drying oven. The quantity of biomass feedstock as sample (combination of wood waste and sawdust waste) for the quality assessment was 0.010g and the ratio of the sample and the catalyst was 1:5.
Quality assessment:
Quality of the resultant bio-oil/bio-gas produced by the standard product (TK-341) and different product (Formula A & Formula B) was analysed by Tandem Micro-Reactor-Gas Chromatography/Mass Spectrometry (TMR-GC/MS) [Fig 1 a & b] in which Reactor 1 and 2 were used at constant temperature 450°C and 750°C respectively. Although reactor 2 is programmable from 1° to 200° C/min, however, in the present study, it was kept constant. Each reactor has its gas control. The Reactor 1 has a single channel for gas flow whereas the Reactor 2 can have up to 3. Helium gas was used in Reactor 1 while hydrogen gas is set in motion to the vapours which were excited from Reactor 1 as they flow in Reactor 2 where the catalyst bed is placed. A solid sample (0.010g) as above stated was placed in the sample cup, which "free falls" in Reactor 1 after the "READY" signal from the Tandem Micro-reactor and the GC/MS software (RX-3050TR-Control). Reactor 2 has a socket for the catalyst tube, which is made of quartz. The quartz wool holds between the catalyst beds. The product (Formula A, Formula B, TK-341) was used separately and the amount of the product used was 0.05g. Reactor 1 must be removed to expose the socket for the catalyst. The catalyst tube was then inserted in the lower section, Reactor 1 was mounted back, and the Tandem Micro-reactor was ready for another run. It should be made sure that before removing Reactor 1 to insert or change the catalyst, the temperature of both reactors should be brought down to room temperature or at least 50°C. After the vapours were passed through the catalyst, the split ratio is kept at 1:50, so the vapours are split. One portion of the vapours flows to the column and the rest is exited due to a split vent. The sample inserted is also separated here. All the electron impact mass spectra were collected as each compound was generated from the GC column Peak identification is done based on spectral information and Retention time (60 minutes in this study). The spectral Library used for quick identification of the compounds is the NIST Mass Spectral library. The quality of the product (Formula A & B and TK-341) was determined by analysing the product by the outcomes of this procedure. The gas chromatograms generated from the test run using the product was compared to the gas chromatograms generated from the test run using the standard TK-341. The peaks generated in the GC were compared. The greater the peak is, the greater the yield of that compound.
Table 2: Comparative Analysis of Formula A vs TK-341
S.No. Compounds Identified
Peak Number (Formula A) Peak Number (For
TK-341) Retention Time Out of 1 hour (For Formula A) Retention Time Out of 1 hour (For TK-341) Area (For Formula A) Area (For TK-341) Desirable/ Un desirable/ New & desirable (For Formula A) Desirable/ Un desirable/ New & desirable (For TK-341)
1 PROPANENITRILE (C3H5N) NA 1 2.846 2.846 0 43498978 - Un desirable
2 PROPANENITRILE (C3H5N) NA 2 2.974 2.974 0 3135419 - Un desirable
3 PROPANE (C3H8) 1 NA 3.846 3.846 85150501 0 New desirable -
4 ISOBUTYL 3-METHYLBUT-3ENYL CARBONATE (C10H18O2) NA 3 4.249 4.249 0 100976883 - Un desirable
5 CYCLOPROPYLACETYLENE (C5H6) 2 4 5.181 5.181 72432159 73253136 Less desirable More desirable
6 CYCLOBUTANE 1,1,2,3,4-PENTAMETHYL (C9H18) 3 NA 5.969 5.969 65769383 0 New desirable -
7 CYCLOBUTANE 1,1,2,3,4-PENTAMETHYL (C9H18) 4 5 6.793 6.793 106754100 14099408 Less desirable More desirable
8 BENZENE (C6H6) NA 6 7.997 7.997 0 23445272 - New desirable
9 1,4-CYCLOHEXADIENE (C6H8) NA 7 8.154 8.154 0 8234242 - New desirable
10 1,4-CYCLOHEXADIENE (C6H8) 5 NA 8.155 8.155 30522937 0 New desirable -
11 BENZENE (C6H6) 6 8 8.765 8.765 147223242 236873311 Less desirable More desirable
12 1,4-CYCLOHEXADIENE (C6H8) 7 NA 9.162 9.162 47952060 0 New desirable -
13 TOLUENE (C7H8) 8 9 12.681 12.681 137483355 179917618 Less desirable More desirable
14 TOLUENE (C7H8) 9 NA 12.807 12.807 35572851 0 New desirable -
15 LEVOGLUCOSENONE (C6H6O3) 10 NA 14.354 14.354 111033147 0 Un desirable -
16 ETHYLBENZENE (C8H10) 11 10 16.339 16.339 50430740 16733391 More desirable Less desirable
17 p-XYLENE (C8H10) 12 11 16.658 16.658 60325178 80364076 Less desirable More desirable
18 STYRENE (C8H8) 13 12 17.356 17.356 98110612 45361985 More desirable Less desirable
19 STYRENE (C8H8) 14 13 17.568 17.568 28950577 40187901 Less desirable More desirable
20 BENZOFURAN 2-METHYL (C9H8O) 15 NA 19.306 19.306 152027997 0 Un desirable -
21 PHENOL (C6H6O) 16 14 19.963 19.963 226132176 15472932 Un desirable Un desirable
22 BENZENE 1-ETHYL-2-METHYL, (C9H10) 17 15,16,17 21.24 21.24 90188421 18758987 More desirable Less desirable
23 BENZOFURAN 2-METHYL (C9H8O) 18 NA 22.614 22.614 128743162 0 Un desirable -
24 INDENE (C9H8) 19 18 23.06 23.06 69166523 69016279 More desirable Less desirable
25 p-CRESOL (C7H8O) 20 NA 23.302 23.302 244659162 0 Un desirable -
26 3,4,5-TRIMETHYLPYRAZOLE (C6H10N2) NA 19 24.992 24.992 0 13779492 - Un desirable
27 1H-PYRROLE 3-ETHYL-2,4-DIMETHYL (C8H31N) NA 20 25.124 25.124 0 9068223 - Un desirable
28 PHENOL 3,4-DIMETHYL (C8H10O) 21 NA 25.824 25.824 129762537 0 Un desirable -
29 2-METHYLINDENE (C10H10) 22 NA 26.355 26.355 132823877 0 New desirable -
30 2-METHYLINDENE (C10H10) 23 21 26.63 26.63 48400501 18320342 More desirable Less desirable
31 2-METHYLINDENE (C10H10) 24 22 26.805 26.805 61620562 43784311 More desirable Less desirable
32 CATECHOL (C6H6O2) 25 NA 27.012 27.012 26754430 0 Un desirable -
33 NAPHTHALENE (C10H8) 26 NA 27.203 27.203 35456470 0 New desirable -
34 PROPYLBENZENE (C9H12) 27 NA 27.502 27.502 49429872 0 New desirable -
35 NAPHTHALENE (C10H8) 28 23 27.769 27.769 115521729 110435773 More desirable Less desirable
36 2-ISOPROPXYPHENOL (C9H12O2) 29 NA 28.296 28.296 53648407 0 Un desirable -
37 PROPYLBENZENE (C9H12) 30 NA 28.929 28.929 34744698 0 New desirable -
38 1-(3-METHYLBUTYL)-2,3,4-TRIMETHYLBENZENE (C14H22) 31 NA 30.11 30.11 99306495 0 New desirable -
39 1,3,5-TRIMETHYLBENZENE (C9H12) 32 NA 31.087 31.087 29731321 0 New desirable -
40 NAPHTHALENE 2-METHYL (C11H10) NA 24 31.209 31.209 0 62114476 - New desirable
41 NAPHTHALENE 2-METHYL (C11H10) 33 NA 31.21 31.21 56637668 0 New desirable -
42 ORTHO-XYLENE (C6H4(CH3)2) 34 NA 31.482 31.482 45974785 0 New desirable -
43 NAPHTHALENE 2-METHYL (C11H10) 35 25 31.705 31.705 38997526 38730474 More desirable Less desirable
44 ORTHO-XYLENE (C6H4(CH3)2) 36 NA 32.133 32.133 146544923 0 New desirable -
45 BIPHENYL (C12H10) NA 26 33.401 33.401 0 14395995 - New desirable
46 NAPHTHALENE, 2-METHYL (C11H10) 37 NA 31.705 31.7 38197526 0 New desirable -
47 NAPHTHALENE 1,2-DIMETHYL (C12H12) NA 27 34.749 34.749 0 8771360 - New desirable
48 1H-INDENE 2,3-DIHYDRO-4,7-DIMETHYL- (C11H14) 38 NA 35.15 35.15 45359639 0 New desirable -
49 RETENE (C18H18) 39 NA 36.606 36.606 37922461 0 New desirable -
50 RETENE (C18H18) 40 NA 36.806 36.806 39922461 0 New desirable -
New desirable: The compound containing carbon and hydrogen as bio-oil/gas is not disclosed in the existing state of art for pyrolysis.
From the results of gas chromatography and after analysing the peaks generated during the pyrolysis process (Table 2 and Fig. 2), With Formula A (1:1), the same compound has been generated at different retention times which could be due to various factors like the feedstock (i.e., the biomass containing wood waste: pine sawdust) and Formula A (1:1). Same compounds were generated at different retention times and their yield was also not the same, some generated higher peaks whereas some generated lower peaks.
These compounds in the case of Formula A (1:1), were,
1. PROPANENITRILE (C3H5N) at peak NA-1 and NA-2 in Formula A vs TK-341 is an Undesirable compound and is not generated in Formula A.
2. CYCLOBUTANE 1,1,2,3,4-PENTAMETHYL (C9H18) generated at peaks 3-NA and 4-5 in Formula A vs TK-341 is a desirable compound with different peak areas of 65769383 and 106754100 respectively in Formula A.
3. 1,4-CYCLOHEXADIENE (C6H8)) at peaks NA-7, 5-NA and 7-NA in Formula A vs TK-341 is a desirable compound with different peak areas of 0, 30522937 and 47952060 respectively in Formula A.
4. TOLUENE (C7H8) generated at peaks 8-9 and 9-NA in Formula A vs TK-341 is a desirable compound with different peak areas of 137483355 and 35572851 respectively in Formula A.
5. STYRENE (C8H8) generated at peaks 13-12 and 14-13 in Formula A vs TK-341 is a desirable compound with different with peak areas 98110612 and 28950577 respectively in Formula A.
6. 2-METHYLINDENE (C10H10) generated at peaks 22-NA, 23-21 and 24-22 in Formula A vs TK-341 is a desirable compound with different peak areas of 132823877, 48400501 and 61620562 respectively in Formula A.
7. NAPHTHALENE (C10H8) generated at peaks 26-NA and 28-NA in Formula A vs TK-341 is a desirable compound with different peak areas of 35456470 and 115521729 respectively in Formula A.
8. PROPYLBENZENE (C9H12) generated at peaks 27-NA and 30-NA in Formula A vs TK-341 is a desirable compound with different peak areas of with peak areas 49429872 and 34744698 respectively in Formula A.
9. NAPHTHALENE 2-METHYL (C11H10) at peaks NA-24, 33-NA, 35-25 and 37-NA in Formula A vs TK-341 is a desirable compound, with peak area of 0, 56637668, 38997526 and 38197526 respectively in Formula A.
10. RETENE (C18H18) generated at peaks 39-NA and 40-NA in Formula A vs TK-341 is a desirable compound with different peak areas of 37922461 and 39922461 respectively Formula A.
The occurrence of identical compounds at different retention times during pyrolysis can be attributed to several key factors:
1. Thermal Decomposition Pathways:
• Different components of the heterogeneous biomass feedstock (Wood waste: Pine Sawdust) can undergo varying decomposition pathways but yield the same final compounds.
• In the data, (refer Table 2 and Fig. 2), few compounds are regenerating at different peaks which is possible due to different precursor molecules present in the compound breaking down to regenerate same compound. For example, As per Table 2 and Fig. 2, STYRENE (C8H8) appears at peaks 13 and 14 of Formula A, possibly due to different precursor molecules breaking down to form styrene.

2. Secondary Reactions:
• During pyrolysis, primary products can undergo secondary reactions at different temperatures and residence times, leading to the formation of similar compounds at different stages.
• For example, As per Table 2 and Fig. 2, The presence of 2-METHYLINDENE (C10H10) at three different peaks (22, 23, 24) for Formula A, suggests multiple reaction pathways or formation stages.
3. Isomerization:
• High temperatures during pyrolysis can cause molecular rearrangements, producing structural isomers that have the same chemical formula but slightly different properties.
• This is evident in the case of NAPHTHALENE (C10H8) (From Table 2 and Fig. 2), appearing at peaks 26 and 28 for Formula A.

4. Catalyst Influence:
• The product as described in Formula A can create different active sites that facilitate similar reactions at different rates or times.
• This explains the varying peak areas for the same compounds, such as CYCLOBUTANE 1,1,2,3,4-PENTAMETHYL (C9H18) generated at peaks 3 and 4 is a desirable compound with different peak areas of 65769383 and 106754100 respectively in Formula A (Refer Table 2 and Fig. 2).

5. Complex Feedstock Composition:
• The heterogeneous nature of the biomass feedstock (Wood waste: Pine Sawdust) means that similar compounds can be produced from different source materials at different times during the process.
• This is reflected in the multiple appearances of compounds like NAPHTHALENE 2-METHYL (C11H10) at peaks 33, 35 and 37 with peak area of 56637668, 38997526 and 38197526 respectively in Formula A. at three different retention times. (Refer Table 2 and Fig. 2).

6. Temperature Gradients:
• Different zones in the pyrolysis reactor may have slight temperature variations, causing similar reactions to occur at different times and rates.
• This can lead to the formation of identical compounds with varying yields, as seen in the peak area differences.
This phenomenon is a testament to the complexity of the pyrolysis process and the multiple reaction pathways possible when working with heterogeneous biomass feedstock and catalysts.




Table 3: Compounds comparison status Formula A (1:1) vs TK-341
Compounds comparison status Formula A TK-341
standard catalyst)
New & desirable compounds 18 5
Desirable compounds 14 14
More desirable compounds - 8 More desirable compounds - 6
Less desirable compounds - 6 Less desirable compounds - 8
Undesirable compounds 8 6
Not found compounds 10 25
Total contributing desirable compounds 18+14 = 32 5+14=19
Total compounds 50 50

As shown in Table 3, the instant composition possesses the equilibrium effect as the standard catalyst and in some efficacy parameter it is better than the standard catalyst.





Table 4: Comparative Analysis of Formula A (1:1) & Formula B (7:3)

Compound (Retention time range) Peak Number (Formula A) Peak Number (Formula B) Retention Time range ( Formula A) Retention Time range (Formula B) Area
(Formula A) Area
(Formula B) Desirable/ Undesirable/new & desirable
(Formula A) Desirable/ Undesirable/new & desirable
(Formula B)
1 PROPANENITRILE (C3H5N) NA 1 2.846 2.846 0 43498978 - Undesirable

2 PROPANE (C3H8) 1 NA 3.846 3.856 85150501 0 New desirable
3 CYCLOPROPYLACETYLENE (C5H6) 2 2 5.19 2.2 72432159 63075171 More Desirable Less Desirable
4 CYCLOBUTANE, 1,1,2,3,4-PENTAMETHYL- (C9H18) 3 NA 5.899 5.969 65769383 0 New desirable -
5 (1-ETHYL-2-METHYLPROPYL) METHYLAMINE (C7H17N) NA 3,4 5.974 5.974 0 69980855 - Undesirable
6 CYCLOBUTANE 1,1,2,3,4-PENTAMETHYL (C9H18) 4 NA 6.793 6.793 106754100 0 New desirable -
7 1,4-CYCLOHEXADIENE (C6H8) 5 6 9.181 9.2 47952060 43837480 More Desirable Less Desirable
8 BENZENE (C6H6) 6 7 9.29 9.25 47952060 43837480 More Desirable Less Desirable
9 1,4-CYCLOHEXADIENE (C6H8) 6A NA 8.778 8.699 37223242 0 New desirable -
10 TOLUENE (C7H8) 7 8,9 12.691 12.745 154976480 86528103 More Desirable Less Desirable
11 1H-PYRAZOLE, 1,3-DIMETHYL (C5H8N2) NA 10 14.375 14.395 0 129357572 - Undesirable
12 LEVOGLUCOSENONE (C6H6O3) 8 NA 14.354 14.354 111033147 - Undesirable -
13 ETHYLBENZENE (C8H10) 9 11 16.348 16.378 50430740 34505519 More Desirable Less Desirable
14 p-XYLENE (C8H10) 10 12 16.67 16.69 60325178 50442826 More Desirable Less Desirable
15 STYRENE (C8H8) 11 13 17.349 17.354 98110612 86008508 More Desirable Less Desirable
16 3,4,5-TRIMETHYLPYRAZOLE (C6H10N2) NA 14 19.333 19.331 0 120765901 - Undesirable
17 STYRENE (C8H8) 12 15 17.568 17.568 28950577 22187901 More Desirable Less Desirable
18 BENZOFURAN 2-METHYL (C9H8O) 13 16 19.306 19.306 152027997 186785204 Undesirable Undesirable
19 PHENOL (C6H6O) 14 NA 23.06 23.1 69166523 0 Undesirable -
20 3,4,5-TRIMETHYLPYRAZOLE (C6H10N2) NA 17 23.056 23.06 0 31608470 - Undesirable
21 BENZENE, 1-ETHYL-2-METHYL, (C9H10) 15 NA 23.222 23.229 90188421 0 New desirable Less desirable
22 1H-PYRROLE, 3-ETHYL-2,4-DIMETHYL (C8H31N) NA 18 24.62 24.67 0 9942073 - Undesirable
23 BENZOFURAN 2-METHYL (C9H8O) 16 19 26.356 26.36 64823877 77915876 Undesirable Undesirable
24 INDENE (C9H8) 17 NA 26.46 26.46 69166523 0 New desirable -
25 BENZOFURAN, 2-METHYL (C9H8O) NA 20 26.56 26.56 0 21399860 - Undesirable
26 p-CRESOL (C7H8O) 18 21 26.602 26.602 244659162 306409072 Undesirable Undesirable
27 PHENOL, 3,4-DIMETHYL (C8H10O) 19 22 25.82 25.827 78589645 95699031 Undesirable Undesirable
28 2-METHYLINDENE (C10H10) 20 NA 26.955 26.955 132823877 0 New desirable -
29 p-CRESOL (C7H8O) NA 23 26.996 23.959 0 16409072 - Undesirable
30 2-METHYLINDENE (C10H10) 21 24 26.98 26.987 48400501 25897460 More Desirable Less desirable
31 2-METHYLINDENE (C10H10) 22 NA 26.785 26.785 61620562 0 New desirable -
32 1,3-BENZENEDIOL, 4-METHYL (C7H8O) NA 25 27 27 0 164090723 - Undesirable
33 1-NAPHTHOL, 1,2,3,4-TRTRAHYDRO-2-METHYL- (C11H14O) NA 26 27.011 27.007 0 64968074 - Undesirable
34 CATECHOL (C6H6O2) 23 27 27.012 27.012 26754430 27978545 Undesirable Undesirable
35 NAPHTHALENE (C10H8) 24 NA 27.203 27.206 35456470 0 New desirable -
36 CATECHOL (C6H6O2) NA 28 27.068 27.059 0 37892563 - Undesirable
37 PROPYLBENZENE (C9H12) 25 NA 27.502 27.502 49429872 0 New desirable -
38 (1-ETHYL-2-METHYLPROPYL) METHYLAMINE (C7H17N) NA 29 27.502 27.502 0 22435478 - Undesirable
39 NAPHTHALENE (C10H8) 26 NA 27.203 27.206 35456470 0 New desirable -
40 NAPHTHALENE (C10H8) 27 30 27.769 27.769 115521729 110435773 More Desirable Less desirable
41 2-ISOPROPXYPHENOL (C9H12O2) 28 NA 28.296 28.296 53648407 0 Undesirable -
42 PHENOL, 2-(1-METHYLETHYL)-METHYLCARBAMATE (C11H15NO) NA 31 28.655 28.66 0 21316988 - Undesirable
43 2-ISOPROPXYPHENOL (C9H12O2) 29 NA 28.337 28.336 53648407 0 Undesirable -
44 PHENOL, 2-(1-METHYLETHYL)-METHYLCARBAMATE (C11H15NO) NA 32 28.337 28.336 0 43721452 - Undesirable
45 1,3-BENZENEDIOL, 3-METHYL (C7H8O) NA 33,34 29.087 29.09 0 10984732 - Undesirable
46 PROPYLBENZENE (C9H12) 30 NA 29.929 29.929 34744698 0 New desirable -
47 1-(3-METHYLBUTYL)-2,3,4-TRIMETHYLBENZENE (C14H22) 31 NA 30.11 30.11 99306495 0 New desirable -
48 1,3-BENZENEDIOL, 4-METHYL (C7H8O) NA 35,36 30.785 30.788 0 164324914 - Undesirable
49 1,3,5-TRIMETHYLBENZENE (C9H12) 32 NA 31.087 31.087 29731321 0 New desirable -
50 NAPHTHALENE 2-METHYL (C11H10) 33 NA 31.21 31.21 56637668 0 New desirable -
51 ORTHO-XYLENE (C6H4(CH3)2) 34 NA 32.133 32.133 146544923 0 New desirable -
52 NAPHTHALENE 2-METHYL (C11H10) 35 NA 31.705 31.705 38997526 0 New desirable -
53 BORAMINE, N,N,1-TRIMETHYL-1-PHENYL (C9H14BN) NA 37 32.139 32.123 0 205026714 - Undesirable
54 ORTHO-XYLENE (C6H4(CH3)2) 36 NA 32.133 32.133 146544923 0 New desirable
55 ETHYL p-HYDROXYBENZOATE (C8H10O2) NA 38 32.64 32.69 0 69655838 - Undesirable
56 NAPHTHALENE, 2-METHYL (C11H10) 37 NA 33.705 33.7 38197526 0 New desirable -
57 1H-INDENE 2,3-DIHYDRO-4,7-DIMETHYL- (C11H14) 38 NA 35.15 35.15 45359639 0 New desirable -
58 1,5-DIHYDROXY-1,2,3,4-TETRAHYDRONAPHTHALENE (C10H12O2) NA 39 35.053 35.0468 0 161098945 - Undesirable
59 RETENE (C18H18) 39 NA 36.606 36.606 37922461 0 New desirable -
60 RETENE (C18H18) 40 NA 36.806 36.806 39922461 0 New desirable -
61 1-NAPHTHALENOL, 2-METHYL NA 40 56.706 57.707 0 92226382444 - Undesirable
New desirable: The compound containing carbon and hydrogen as bio-oil/gas is not disclosed in the existing state of art for pyrolysis







Similarly like comparative analysis of Formula A and TK-341, the results of gas chromatography of Formula A (1:1) and Formula B (7:3) are discussed as herein below:
These compounds in the case of Formula A (1:1) are,
1. CYCLOBUTANE, 1,1,2,3,4-PENTAMETHYL- (C9H18) generated at peaks 3-NA and 4-NA in Formula A (1:1) vs Formula B (7:3) is a desirable compound with different peak areas of 65769383 and 106754100 respectively in Formula A (1:1).
2. 1,4-CYCLOHEXADIENE (C6H8) generated at peaks 5-6 and 6A-NA in Formula A (1:1) vs Formula B (7:3) is a desirable compound with different peak areas of 47952060 and 37223242 respectively in Formula A (1:1).
3. STYRENE (C8H8) generated at peaks 11-13 and 12-15 in Formula A (1:1) vs Formula B (7:3) is a desirable compound with different peak areas of 98110612 and 28950577 respectively in Formula A (1:1).
4. 3,4,5-TRIMETHYLPYRAZOLE (C6H10N2) generated at peaks NA-14 and NA-17 in Formula A (1:1) vs Formula B (7:3) is an undesirable compound and is not generated in Formula A (1:1).
5. BENZOFURAN 2-METHYL (C9H8O) generated at peaks 16-19 and NA-20 in Formula A (1:1) vs Formula B (7:3) is an undesirable compound with different peak areas of 64823877 and 0 respectively in Formula A (1:1).
6. p-CRESOL (C7H8O) generated at peaks 18-21 and NA-23 in Formula A (1:1) vs Formula B (7:3) is an undesirable compound with different peak areas of 244659162 and 0 respectively in Formula A (1:1).
7. 2-METHYLINDENE (C10H10) generated at peaks 20-NA, 21-24 and 22-NA in Formula A (1:1) vs Formula B (7:3) is a desirable compound with different peak areas of 132823877, 48400501 and 61620562 respectively in Formula A (1:1).
8. 1,3-BENZENEDIOL, 4-METHYL (C7H8O) generated at peaks NA-25 and NA-33,34 in Formula A (1:1) vs Formula B (7:3) is an undesirable compound and is not generated in Formula A (1:1).
9. CATECHOL (C6H6O2) generated at peaks 23-27 and NA-24 in Formula A (1:1) vs Formula B (7:3) is an undesirable compound with different peak areas of 26754430 and 0 respectively in Formula A (1:1).
10. NAPHTHALENE (C10H8) generated at peaks 26-NA and 27-30 in Formula A (1:1) vs Formula B (7:3) is a desirable compound with different peak areas of 35456570 and 115521729 respectively in Formula A (1:1).
11. PROPYLBENZENE (C9H12) generated at peaks 25-NA and 30-NA in Formula A (1:1) vs Formula B (7:3) is a desirable compound with different peak areas of 49429872 and 34744698 respectively in Formula A (1:1).
12. 2-ISOPROPXYPHENOL (C9H12O2) generated at peaks 28-NA and 29-NA in Formula A (1:1) vs Formula B (7:3) is an undesirable compound with different peak areas of53648407 and 53648407 respectively in Formula A (1:1).
13. PHENOL, 2-(1-METHYLETHYL)-METHYLCARBAMATE (C11H15NO) generated at peaks NA-31 and NA-32 in Formula A (1:1) vs Formula B (7:3) is an undesirable compound and is not generated in Formula A (1:1).
14. NAPHTHALENE 2-METHYL (C11H10) generated at peaks 33-NA, 35-NA, 37-NA in Formula A (1:1) vs Formula B (7:3) is a desirable compound with different peak areas of 56637668, 38997526 and 38197526 respectively in Formula A (1:1).
15. ORTHO-XYLENE (C6H4(CH3)2) generated at peaks 34-NA and 36-NA in Formula A (1:1) vs Formula B (7:3) is a desirable compound with different peak areas of 146544923 and 146544923 respectively in Formula A (1:1).
16. RETENE (C18H18) generated at peaks 39-NA and 40-NA in Formula A (1:1) vs Formula B (7:3) is a desirable compound with different peak areas of 37922461 and 39922461 respectively in Formula A (1:1).

The occurrence of identical compounds at different retention times during pyrolysis can be attributed to several key factors:
1.Thermal Decomposition Pathways:
• Different components of the heterogeneous biomass feedstock (Wood waste: Pine Sawdust) can undergo varying decomposition pathways but yield the same final compounds.
• In the data, (refer Table 4 and Fig. 3), Few compounds are regenerating at different peaks. It is possibly due to different precursor molecules present in the compound breaking down to regenerate same compound. For example, As per Table 4 and Fig. 3, STYRENE (C8H8) appears at peaks 11 and 12 of Formula A (1:1), possibly due to different precursor molecules breaking down to form styrene.
2.Secondary Reactions:
• During pyrolysis, primary products can undergo secondary reactions at different temperatures and residence times, leading to the formation of similar compounds at different stages.
• For example, As per Table 4 and Fig. 3, The presence of 2-METHYLINDENE (C10H10) at three different peaks (20, 21, 22) for Formula A (1:1), suggests multiple reaction pathways or formation stages.
3. Isomerization:
• High temperatures during pyrolysis can cause molecular rearrangements, producing structural isomers that have the same chemical formula but slightly different properties.
• This is evident in the case of NAPHTHALENE (C10H8) (From Table 4 and Fig. 3), appearing at peaks 26 and 27 for Formula A (1:1).
4. Catalyst Influence:
• The product as described in Formula A (1:1) can create different active sites that facilitate similar reactions at different rates or times.
• This explains the varying peak areas for the same compounds, such as CYCLOBUTANE 1,1,2,3,4-PENTAMETHYL (C9H18) generated at peaks 3 and 4 is a desirable compound with different peak areas of 65769383 and 106754100 respectively in Formula A (1:1) (Refer Table 4 and Fig. 3).
5. Complex Feedstock Composition:
• The heterogeneous nature of the biomass feedstock (Wood waste: Pine Sawdust) means that similar compounds can be produced from different source materials at different times during the process.
• This is reflected in the multiple appearances of compounds like NAPHTHALENE 2-METHYL (C11H10) at peaks 33, 35 and 37 with peak area of 56637668, 38997526 and 38197526 respectively in Formula A (1:1). at three different retention times. (Refer Table 4 and Fig. 3).
6. Temperature Gradients:
• Different zones in the pyrolysis reactor may have slight temperature variations, causing similar reactions to occur at different times and rates.
• This can lead to the formation of identical compounds with varying yields, as seen in the peak area differences.
This phenomenon is a testament to the complexity of the pyrolysis process and the multiple reaction pathways possible when working with heterogeneous biomass feedstock and catalysts.

Table 5: Compounds comparison status Formula A (1:1) vs Formula B (7:3)
Compounds comparison status Formula A
(SS : SSC = 1:1) Formula B
(SS : SSC = 7:3)
New& desirable compounds 22 0
Desirable compounds 10 10
More desirable compounds - 10 More desirable compounds - 0
Less desirable compounds - 0 Less desirable compounds - 10
Undesirable compounds 8 25
Not found compounds 20 26
Total contributing desirable compounds 22 + 10 = 32 10
Total compounds 61 61

As shown in Table 5, the desired effect (bio-oil/biogas with more number of desirable compounds and less number of undesirable compounds) was found in Formula A which might be because of combination of SS and SSC in a manner of 1:1. Table 5 also speaks that not all the combination of SS and SSC attains the desired effect. Formula B (wherein the SS : SSC is 7:3) possess contrary effect i.e. bio-oil/biogas with less number of desirable compounds and more number of undesirable compounds which is not desired.

Although the foregoing description of the present invention has been shown and described with reference to particular embodiments and applications thereof, it has been present for purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the particular embodiments and applications disclosed. It will be apparent to those having ordinary skill in the art that a number of changes, modifications, variations, or alterations to the invention as described herein may be made, none of which departs from the spirit or scope of the present invention. The particular embodiments and applications were chosen and described to provide the best illustration of the principles of the invention and its practical application thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such changes, modifications, variations, and alterations should therefore be seen as being within the scope of the present invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.
, Claims:1. A waste substance-based composition useful as catalyst for pyrolysis of a biomass including a combination of steel slag (SS) and sewage sludge char (SSC).
2. A waste substance-based composition useful as catalyst for pyrolysis as claimed in claim 1, wherein the sewage sludge char is not activated.
3. The waste substance-based composition useful as catalyst for pyrolysis as claimed in claim 1, wherein the ratio of steel slag and sewage sludge char is 1:1 by weight.
4. The waste substance-based composition useful as catalyst for pyrolysis as claimed in claim 1, wherein the sewage sludge char includes fixed carbon of 70%.
5. The waste substance-based composition useful as catalyst for pyrolysis as claimed in claim 1, wherein the surface area of sewage sludge char is400 m2/g.
6. The waste substance-based composition useful as catalyst for pyrolysis as claimed in claim 1, wherein ash content and volatilities of sewage sludge char is 30-50% and 20% respectively.
7. The waste substance-based composition useful as catalyst for pyrolysis as claimed in claim 1, wherein the particle size of steel slag and sewage sludge char is 0.074-0.15 mm and 0.5-1mm respectively.
8. A process for preparing waste substance-based composition useful as catalyst comprising the steps of

i) preparing steel slag product (SS) by obtaining the SS and washing the same with ionised water and subjecting the product for air drying for 24 hours to remove presence of any impurities like dust, dirt etc followed by oven drying for 2 hours at a temperature of 105°C to remove complete moisture followed by calcination at 800°C for 4 hours;
ii) preparing sewage sludge char product (SSC) by obtaining the raw sewage sludge and then subjecting for air drying for 24 hours at room temperature followed by heating at 250°C at a rate of 5°C per minute in an inert atmosphere till it reaches up to 700°C and holding the product at 700°C for 3 hours;
iii) mixing the product of step (i) and step (ii).

9. The process as claimed in claim 8, wherein the steel slag product of step (i) and sewage sludge char of step (ii) is mixed (in step-iii) in a ratio of 1:1 by weight.

10. The waste substance-based composition useful as catalyst as claimed in any preceding claim, wherein the biomass is selected from wood waste, pine sawdust or a combination thereof.

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