Using chicken-eggshell-derived calcium oxide as an ideal catalyst towards esterification of high-included free fatty acid waste cooking oil; Application of Taguchi method
Ali Shokuhi Rad
1
(
Department of Chemical Engineering, Qaemshahr Branch, Islamic Azad University, Qaemshahr, Iran
)
Mazyar Sharifzadeh Baei
2
(
Department of Chemical Engineering, Ayatollah Amoli Branch, Islamic Azad University, Amol, Iran
)
Keywords: Biodiesel, catalyst, Transesterification, Waste cooking oil, Waste chicken-eggshell,
Abstract :
In this study, we used chicken eggshells as a low-cost catalyst for the esterification process of oil with a high fatty acid (FFA) content. We used the Taguchi method to optimize both esterification and transesterification steps. The waste chicken eggshell was calcinated at a temperature of 700°C for 4 hours to synthesize calcium oxide (CaO) active catalyst. The newly obtained catalyst was characterized by BET, TEM, and SEM. Then, this catalyst was employed for the transesterification of waste cooking oil. This work aimed to optimize critical parameters in preparing biodiesel production of waste cooking oil to maximize efficiency. Hence, the effects of reaction temperature, reaction time, catalyst amount, and methanol/ oil molar ratio on biodiesel yield were investigated and optimized through the Taguchi method. The maximum biodiesel efficiency is calculated to be 84% through transesterification at the following optimum conditions: the reaction temperature of 80°C, the reaction time of 1.5 h, the ratio of methanol/oil of 10:1, and the catalyst amount of 2% w/w.
17 | Page
Abstract
In this study, we used chicken eggshells as a low-cost catalyst for the esterification process of oil with a high fatty acid (FFA) content. We used the Taguchi method to optimize both esterification and transesterification steps. The waste chicken eggshell was calcinated at a temperature of 700°C for 4 hours to synthesize calcium oxide (CaO) active catalyst. The newly obtained catalyst was characterized by BET, TEM, and SEM. Then, this catalyst was employed for the transesterification of waste cooking oil. This work aimed to optimize critical parameters in preparing biodiesel production of waste cooking oil to maximize efficiency. Hence, the effects of reaction temperature, reaction time, catalyst amount, and methanol/ oil molar ratio on biodiesel yield were investigated and optimized through the Taguchi method. The maximum biodiesel efficiency is calculated to be 84% through transesterification at the following optimum conditions: the reaction temperature of 80°C, the reaction time of 1.5 h, the ratio of methanol/oil of 10:1, and the catalyst amount of 2% w/w.
Keywords: Biodiesel, Transesterification, Waste chicken-eggshell, Waste cooking oil, catalyst
Introduction
Recently, renewable energy sources such as biodiesel and biomass from environmental wastes have received significant attention. These new biofuels reduce any dependence on fossil fuels. They can be used instead of fossil fuels responsible for environmental pollution. For this reason, today, biofuels are known as alternative fuels [1]. Biodiesel (frequently defined as an alkyl monoester) is the best alternative for petroleum-derived diesel fuel [2, 3]. Owing to their energy content similar to diesel, they can be used commonly in fuel blends [4, 5], resulting in a significant reduction in emissions of gaseous pollutants such as CO, SOx, and organic compounds [6]. Transesterification is the simplest and most cost-effective way to produce biodiesel from oil [4]. Transesterification, called alcoholysis, is the reaction of a fat or oil with an alcohol to form esters and glycerol. In that reaction, one mole of triglyceride reacts with three moles of alcohol (normally methanol) in the presence of catalysts. Usually, transesterification of vegetable oil to biodiesel (fatty acid methyl ester, FAME) can be catalyzed by either acids or bases [7, 8]. High values of FFA cause the production of biodiesel incompatible with essential catalysts. Therefore, there are two alternative methods for solving this problem. The first method is a two-step process that needs primary acid-catalyzed esterification of the FFA, followed by a basic catalyzed transesterification. A single process uses an acidic catalyst that simultaneously catalyzes esterification and transesterification reactions in the second method.
Heterogeneous catalysts provide easy and cost-effective separations in which the regeneration of the catalyst is possible [9]. Heterogeneous essential catalysts include alkaline earth metal oxides such as calcium oxide (CaO), magnesium oxide (MgO), and hydrotalcite (Mg6Al2CO3(OH)16·4(H2O)) [10, 11].
Eggshells are a network of protein fibers associated with crystals of calcium carbonate (CaCO3), magnesium carbonate (MgCO3) and calcium phosphate (Ca3(PO4)2), and also some organic substances and water. CaCO3, the significant component of eggshells (96%), is an amorphous crystal that can be crystallized to calcite (hexagonal crystal) [12, 13].
CaCO3 particles of eggshell can be used as raw material to form CaO heterogeneous catalysts; not only will the waste materials be eliminated (environmentally favorable), but the cost of biodiesel processing will be decreased (cost-effectiveness). Investigations related to the eggshell waste utilize wastes, a renewable catalyst, were carried out several times by many researchers in their works [14, 15, 16]. Recently, natural calcium sources from waste materials have been considered a new trend for biodiesel production [17].
Wei et al. [16] used eggshells as a catalyst in the transesterification reaction of soybean oil with methanol. They reported that the modification of eggshells at a temperature of seven hundred oC could be active in its particles as catalysts for the transesterification process.
Niju al. [18] used successive steps (calcination-hydration-dehydration ) to activate eggshell-derived CaO catalyst. The calcination process at a nine hundred degrees Celsius temperature was applied in their work. However, the only problem in their work is the cost of the operation, which is necessary for the modification of resulted catalyst. Moreover, they did not use their resulted catalyze to optimize conditions for biodiesel production.
We first calcinated the chicken eggshell (as a cost-effective source) to create a CaO active catalyst in the present study. Then, this catalyst was utilized for the transesterification of waste cooking oil. In this study, Taguchi methodology was used to optimize different biodiesel production variables, including temperature, time, methanol/oil ratio, and the amount of catalyst to get the maximum efficiency.
Materials and Methods
Materials
Frying oil waste was collected from a local restaurant in Babol (IRAN). This oil includes solid impurities such as food residues and water. For this reason, before any use, we filtered this crude oil to make it ready to use for biodiesel production. The main chemical substances used in our study are listed: methanol (Merck), potassium hydroxide (Merck), ethanol (Flucka), hydrochloric acid (Fluka), and phenolphthalein (Sigma-Aldrich).
Eggshells were collected from a pastry shop in north Iran. Before any use, they were washed carefully in tap water to eliminate any surplus material adhered to on their surface and washed two times with distilled water. The rinsed eggshells were dried for 24 hours and then crushed into powder (see Fig. 1).
Figure 1. Preparation of CaO catalyst derived from eggshell waste
Catalyst characterization
We used Scanning Electron Microscopy (SEM), Model: F E I Quanta FEG 200 and Transmission Electron Microscope (TEM), Hitachi High-Technologies Europe GmbH, Krefeld, Germany, model HF2000 analyses to confirm the morphology of the calcined catalyst. The surface areas of calcined and non-calcined CaO were determined by BET analysis using an ASAP 2020 surface area analyzer (Micromeritics).
Taguchi method and design of experiment
The Taguchi optimization method and experiment design apply fractional factorial test designs that reduce the number of experiments. The Taguchi method and investigation technique can evaluate several process variables that disturb the performance characteristic while minimizing the number of test runs [9]. As shown in Tables 1 and 2, we considered four factors: time (minutes), temperature (°C), methanol/oil ratio, and catalyst amount at four different levels. Using Taguchi methodology, the average impact of each variable on the acidity (in esterification) and the biodiesel production efficiency (in transesterification) were investigated. As a result, the best possible experimental outcomes are determined and examined, which is the main advantage of the present study compared to other biodiesel production methods.
Table 2.
Results and Discussion
The morphology of eggshell-derived CaO
The dried eggshell was shaped into small pieces using crushing and then calcined in a muffle furnace under static air conditions at 700 °C for four h to produce active CaO particles.
The TEM and SEM images of the eggshell-derived CaO catalyst are given in Fig. 2. Both TEM and SEM analyses confirm that the typical morphology of particles has a micrometer in width (1.7 to 2.4 μm). Moreover, the BET analysis was used to conclude the specific surface area of the particles. According to the BET analysis, the mean surface area of the eggshell-derived CaO was calculated to be 3.17 m2 /gr. This high surface area points towards the suitability of the achieved CaO particles as an ideal catalyst for the transesterification process.
|
|
(a) | (b) |
Figure 2. The TEM (a) and SEM (b) pictures of eggshell derived CaO catalyst
Esterification
The measured free fatty acid (FFA) content for the crude oil was 6.8 %, which means it is not suitable to be used directly for transesterification due to the saponification. Therefore, it requires a pretreatment step (esterification) to reduce the FFA content of fat to less than 1% [7]. Literature reviews show that heterogeneous catalysts for the esterification process have not yielded satisfactory results [7, 8, 9]. Another drawback of heterogeneous catalysis is the necessity for harsh reaction conditions [9]. Solve HCl homogenous catalyst to solve these problems as a cost-effective material.
Tables 1 and 2 depict the runs for the esterification and transesterification processes, respectively. For each run, the FFA content value was considered. All deals of 16 Taguchi suggested runs and FFA percentage results are listed in Table 3.
Then obtained FFA values in all experiments were entered into the Taguchi algorithm program, and the mean graph of each variable on the amount of % FFA was achieved. The average impact of HCl amount (Fig. 3), the molar ratio of methanol/ oil (Fig. 4), time (Fig. 5), and temperature (Fig. 6) are respectively indicated in the amount of % FFA. The minimum amount of the average impact of the factor in each chart is considered the best level. In each graph, the horizontal axis indicates the variable levels.
Figure 3. Average effects of HCl concentration (left to right : 0.5, 1, 1.5 and 2 gr) on FFA%
Figure 4. Average effects of Methanol/Oil (left to right 3:1, 6:1, 9:1, and 12:1) on % FFA
Figure 5. Average effects of time (left to right 30, 60, 90, and 120 min) on % FFA
Figure 6. Average effects of temperature (left to right 60,80, 100, and 120 °C) on %FFA
According to the minimum levels in the specified levels for the variables, the highest effects on decreasing the % FFA is determined. The optimal values of the variables are achieved with the amount of the 2% w/w HCl catalyst (1 gr catalyst with 50 gr oil), the molar ratio of alcohol to oil as (12:1), the time of 30 minutes, and the temperature of 60°C. FFA content was reduced from 6.8% to 0.67 by applying these situations for the esterification the crude oil.
Transesterification
Reducing the crude oil's FFA content to 0.7 % makes it possible for transesterification afterward. To optimize the parameters of transesterification, we again used the Taguchi algorithm. The values of the levels for transesterification are listed in Table 2. On the other hand, Table 4 represents the transesterification parameters of 16 Taguchi suggested runs and their efficiency in biodiesel production.
In each run, the specified amount of eggshell-derived CaO catalyst, the molar ratio of methanol/oil, temperature, and time have been used to investigate their effect on biodiesel production. The biodiesel efficiency is calculated according to the following relationship and is entered into the Taguchi algorithm. Finally, the mean effect of each variable is achieved.
The biodiesel efficiency = (methyl ester mass/ oil mass) × 100 | (eq. 1) |
In the following, the average effects of eggshell-derived CaO catalyst (see Fig. 7), molar ratios of methanol/oil (see Fig. 8), times (see Fig. 9), and temperatures (see Fig. 10) on biodiesel efficiency have been indicated. The maximum amount of the average impact of the factor in each figure is considered the best level. In each graph, the horizontal axis indicates the level of variables.
Figure 7. Average effects of the amounts of CaO catalyst (left to right: 1, 2, 3, and 4
gr) on %Yield
Figure 8. Average effects of methanol/oil ratio (left to right: 6:1, 8:1, 10:1, and 12:1) on % Yield
Figure 9. Average effects of different times of reaction (left to right:1.5, 2.5, 3.5, and 4.5
hr) on % Yield
Figure 10. Average effects of the different temperatures of the reaction mixture (left to right: 60, 80,100, and 120 °C) on %Yield
Considering the maximum biodiesel yield at each level, the highest effects on the efficiency of biodiesel are determined. According to Figs 7-10, the optimal values of the variables are found in the following situations: methanol/oil molar ratio 10:1, catalyst amount: 2% w/w (1 gr catalyst in 50 gr oil), reaction time: 90 min, and reaction temperature: 80°C, where the highest efficiency for biodiesel is indicated to be 84%.
In most cases, the reaction temperature is close to the boiling point of alcohol in the atmosphere. The boiling point of methanol is between 60 and 70 ° C temperature at 1 atm. However, the rising temperature can generally affect the efficiency of both esterification and transesterification processes. This study reported the optimal temperature for the esterification and transesterification at 60°C and 80°C, respectively. In addition, the effects of different reaction times on biodiesel efficiency have been studied. We found 30 min and 90 min as the optimal reaction times for esterification and transesterification processes. The amount of the eggshell-derived CaO catalyst is one factor that has the highest effects on biodiesel efficiency. Compared to the critical values for the catalyst concentration reported between 0.25 to 3% oil weight (w/w) in biodiesel production [21, 22], we obtained the optimal values of the eggshell-derived CaO catalyst to be 2 % w/w for the transesterification process.
Conclusion
In this study, a two steps process was developed to convert waste cooking oil to methyl ester. We synthesized and characterized the eggshell-derived CaO as an inexpensive catalyst for the transesterification of waste cooking oil. The first step was acid treatment, which reduced the oil’s FFA content to less than 1% using an acid-catalyzed reaction with a ratio of methanol/oil to 12:1 at 60˚C temperature and 30 min reaction time. The effect of molar ratio, amount of catalyst, reaction temperature, and reaction time were also analyzed in the transesterification process. After acid treatment, an alkaline transesterification reaction was carried out at 1gr eggshell-derived CaO catalyst, a ratio of methanol/oil to 10:1, 80˚C for 90 min. The maximum yield of biodiesel is calculated to be 84% using this catalyst.
References
[1]EL-Seesy, Ahmed I., Mostafa E. Elshobary, and Zhixia He. "Biofuel versus fossil fuel." Handbook of Algal Biofuels. Elsevier (2022) 181-193.
[2] Shokuhi Rad A., Ganjian E., Afrashteh S., Ghorbani HR, "Functionalization of MWCNT by–SO3H and–COOH Groups and Their Application as Solid Acidic Catalysts for Esterification of Waste Chicken Fat", Chemical and Biochemical Engineering Quarterly, Vol. 31, (2017), 69-75.
[3] Shokuhi Rad A., Mehdipour P., Vaziri A., Mirabi A., Binaeian E., "Esterification of Waste Cooking Oil Followed by Transesterification by CaO Nanoparticles: Application of Taguchi Methodology" Journal of Nanoanalysis, Vol. 4, (2017), 150-158.”
[4] Shokuhi Rad A., Hosseininia M., Ardestani F., Nayebzadeh, H., "Esterification of Waste Chicken Fat: Sulfonated MWCNT Toward Biodiesel Production", Waste and Biomass Valorization, Vol. 9, (2018), 591-599.
[5] Demirbas A., "Progress and recent trends in biofuels,” Progress in Energy and Combustion Science, Vol.33, (2007), 1-18.
[6] Luijten, J., "Bioenergy Options for a Cleaner Environment: In Developed and Developing Countries", Agricultural Systems, Vol. 83, No.3, (2005), 329-331.
[7] Shaik, M. R., Adil, S. F., ALOthman, Z. A., & Alduhaish, O. M. "Fumarate Based Metal–Organic Framework: An Effective Catalyst for the Transesterification of Used Vegetable Oil". Crystals, 12 (2022), 151.
[8] Hamza, M., Ayoub, M., Shamsuddin, R.B., Mukhtar, A., Saqib, S., Zahid, I., Ameen, M., Ullah, S., Al-Sehemi, A.G. and Ibrahim, M. "A review on the waste biomass derived catalysts for biodiesel production". Environmental Technology & Innovation, 21 (2021) 101200.
[9]Sharma YC, Singh B. Upadhyay S. N, "Advancements in development and characterization of biodiesel: a review", Fuel, Vol. 87, (2008), 2355-2373.
[10]Liu X., He H., Wang Y., Zhu S., Piao X., "Transesterification of soybean oil to biodiesel using CaO as a solid base catalyst", Fuel, Vol. 87, (2008), 216-221.
[11] Kouzu, M., Kasuno, T., Tajika, M., Sugimoto, Y., Yamanaka, S., Hidaka, J., "Calcium oxide as a solid base catalyst for transesterification of soybean oil and its application to biodiesel production", Fuel, Vol. 87, (2008), 2798-2806.
[12] Buasri A., Chaiyut N., Loryuenyong V., Wongweang C., Khamsrisuk S., "Application of eggshell wastes as a heterogeneous catalyst for biodiesel production", Sustainable Energy, Vol. 1, (2013), 7-13.
[13] Oliveira DA., Benelli P., Amante ER., "A literature review on adding value to solid residues: egg shells", Journal of Cleaner Production, Vol.46, (2013), 42-47.
[14] Boro J., Deka D., Thakur A. J., "A review on solid oxide derived from waste shells as catalyst for biodiesel production", Journal of Renewable and Sustainable Energy, Vol.16, (2012), 904-910.
[15] Sharma Y. C., Singh B., Korstad J., "Application of an efficient nonconventional heterogeneous catalyst for biodiesel synthesis from Pongamiapinnata oil", Energy & Fuels, Vol.24, (2010), 3223-3231.
[16]Wei Z., Xu C., Li B , "Application of waste eggshell as low-cost solid catalyst for biodiesel production", Bioresource Technology, Vol.100, (2009), 2883-2885.
[17] Khemthong P., Luadthong C., Nualpaeng W., Changsuwan P., Tongprem P., Viriya-Empikul N., Faungnawakij K., "Industrial eggshell wastes as the heterogeneous catalysts for microwave-assisted biodiesel production", Catalysis Today, Vol.190, (2012), 112-116.
[18] Niju S., Begum KMS., Anantharaman N., "Modification of eggshell and its application in biodiesel production", Journal of Saudi Chemical Society, Vol.18, (2014), 702-706
[19] Khalilzadeh, M. A., Hosseini, S., Rad, A. S., & Venditti, R. A. Synthesis of grafted nanofibrillated cellulose-based hydrogel and study of its thermodynamic, kinetic, and electronic properties. Journal of Agricultural and Food Chemistry, 68(32) (2020), 8710-8719.
[20]Brunschwig C. , Moussavou W. , Blin J., "Use of bioethanol for biodiesel production", Progress in Energy and Combustion Science, Vol.38, (2012), 283-301.
[21]Bouaid A. , Martinez M. , Aracil J., "Biorefinery approach for coconut oil valorizationa statistical study"‚ Bioresource Technology , Vol.101, (2010), 4006-4012.
[22] Dorado MP. , Ballesteros E. , Mittelbach M. Lopez FJ. , "Kinetic parameters affecting the alkali-catalyzed transesterification process of used olive oil"‚ Energy & Fuels, Vol. 18, (2004), 1457-1462.
Tables
Table 1.The values of different levels for esterification
Factors | level | |||
Time (min) | Temperature (•c) | Methanol/Oil (molar ratio) | HCl(gr) | |
30 | 60 | 3:1 | 0.5 | 1 |
60 | 80 | 6:1 | 1 | 2 |
90 | 100 | 9:1 | 1.5 | 3 |
120 | 120 | 12:1 | 2 | 4 |
Table 2.The values of different levels for transesterification
Factors | level | |||
Time (hr) | Temperature (•c) | Methanol/Oil (molar ratio) | eggshell-derived CaO catalyst (gr) | |
1.5 | 60 | 6:1 | 1 | 1 |
2.5 | 80 | 8:1 | 2 | 2 |
3.5 | 100 | 10:1 | 3 | 3 |
4.5 | 120 | 12:1 | 4 | 4 |
Table 3.The suggested runs by Taguchi methodology in the esterification stage along with the results of % FFA (HCl: gr, Methanol/oil: mol/mol, time: min, temperature: oC)
%FFA | Level | Quantity | Factor | No. | %FFA | Level | Quantity | Factor | No |
1.68% | 3 | 3 | HCl | 9 | %0.95 | 1 | 1 | HCl | 1 |
1 | 3 | Methanol/Oil | 1 | 3 | Methanol/Oil | ||||
4 | 120 | Time | 1 | 30 | Time | ||||
3 | 100 | Temperature | 1 | 60 | Temperature | ||||
%0.72 | 3 | 3 | HCl | 10 | %0.95 | 1 | 1 | HCl | 2 |
2 | 6 | Methanol/Oil | 2 | 6 | Methanol/Oil | ||||
3 | 90 | Time | 2 | 60 | Time | ||||
4 | 120 | Temperature | 2 | 80 | Temperature | ||||
0.67% | 3 | 3 | HCl | 11 | 1.68% | 1 | 1 | HCl | 3 |
3 | 9 | Methanol/Oil | 3 | 9 | Methanol/Oil | ||||
2 | 60 | Time | 3 | 90 | Time | ||||
1 | 60 | Temperature | 3 | 100 | Temperature | ||||
0.67% | 3 | 3 | HCl | 12 | 0.67% | 1 | 1 | HCl | 4 |
4 | 12 | Methanol/Oil | 4 | 12 | Methanol/Oil | ||||
1 | 30 | Time | 4 | 120 | Time | ||||
2 | 80 | Temperature | 4 | 120 | Temperature | ||||
%1.06 | 4 | 4 | HCl | 13 | %0.89 | 2 | 2 | HCl | 5 |
1 | 3 | Methanol/Oil | 1 | 3 | Methanol/Oil | ||||
2 | 60 | Time | 3 | 90 | Time | ||||
4 | 120 | Temperature | 2 | 80 | Temperature | ||||
%0.89 | 4 | 4 | HCl | 14 | %0.72 | 2 | 2 | HCl | 6 |
2 | 6 | Methanol/Oil | 2 | 6 | Methanol/Oil | ||||
1 | 30 | Time | 4 | 120 | Time | ||||
3 | 100 | Temperature | 1 | 60 | Temperature | ||||
%0.95 | 4 | 4 | HCl | 15 | %0.72 | 2 | 2 | HCl | 7 |
3 | 9 | Methanol/Oil | 3 | 20.59 | Methanol/Oil | ||||
4 | 120 | Time | 1 | 30 | Time | ||||
2 | 80 | Temperature | 4 | 120 | Temperature | ||||
0.67% | 4 | 4 | HCl | 16 | %0.78 | 2 | 2 | HCl | 8 |
4 | 12 | Methanol/Oil | 4 | 27.45 | Methanol/Oil | ||||
3 | 90 | Time | 2 | 60 | Time | ||||
1 | 60 | Temperature | 3 | 100 | Temperature |
Table 4.The suggested runs by Taguchi methodology in the transesterification stage along with the
results of biodiesel yield (% Yield)
%Yield | Level | Quantity | Factor | NO | %Yield | Level | Quantity | Factor | No |
81 | 1 | 2 | CaO %Wt | 9 | 76 | 1 | 2 | CaO %Wt | 1 |
3 | 10 | Methanol/Oil | 1 | 6 | Methanol/Oil | ||||
3 | 3.5 | Time | 1 | 1.5 | Time | ||||
4 | 120 | Temperature | 1 | 60 | Temperature | ||||
70 | 2 | 4 | CaO %Wt | 10 | 90 | 2 | 4 | CaO %Wt | 2 |
4 | 12 | Methanol/Oil | 2 | 8 | Methanol/Oil | ||||
3 | 3.5 | Time | 1 | 1.5 | Time | ||||
3 | 100 | Temperature | 2 | 80 | Temperature | ||||
85 | 3 | 6 | CaO %Wt | 11 | 80 | 3 | 6 | CaO %Wt | 3 |
1 | 6 | Methanol/Oil | 3 | 10 | Methanol/Oil | ||||
3 | 3.5 | Time | 1 | 1.5 | Time | ||||
2 | 80 | Temperature | 3 | 100 | Temperature | ||||
75 | 4 | 8 | CaO %Wt | 12 | 83 | 4 | 8 | CaO %Wt | 4 |
2 | 8 | Methanol/Oil | 4 | 12 | Methanol/Oil | ||||
3 | 3.5 | Time | 1 | 1.5 | Time | ||||
1 | 60 | Temperature | 4 | 120 | Temperature | ||||
93 | 1 | 2 | CaO %Wt | 13 | 86 | 1 | 2 | CaO %Wt | 5 |
4 | 12 | Methanol/Oil | 2 | 8 | Methanol/Oil | ||||
4 | 4.5 | Time | 2 | 2.5 | Time | ||||
2 | 80 | Temperature | 3 | 100 | Temperature | ||||
87 | 2 | 4 | CaO %Wt | 14 | 88 | 2 | 4 | CaO %Wt | 6 |
3 | 10 | Methanol/Oil | 1 | 6 | Methanol/Oil | ||||
4 | 4.5 | Time | 2 | 2.5 | Time | ||||
1 | 60 | Temperature | 4 | 120 | Temperature | ||||
75 | 3 | 6 | CaO %Wt | 15 | 50 | 3 | 6 | CaO %Wt | 7 |
2 | 8 | Methanol/Oil | 4 | 12 | Methanol/Oil | ||||
4 | 4.5 | Time | 2 | 2.5 | Time | ||||
4 | 120 | Temperature | 1 | 60 | Temperature | ||||
65 | 4 | 8 | CaO %Wt | 16 | 85 | 4 | 8 | CaO %Wt | 8 |
1 | 6 | Methanol/Oil | 3 | 10 | Methanol/Oil | ||||
4 | 4.5 | Time | 2 | 2.5 | Time | ||||
3 | 100 | Temperature | 2 | 80 | Temperature |