Conversion of Palm Oil (CPO) into Fuel Biogasoline through Thermal Cracking Using a Catalyst Based Na-Bentonite and Limestone of Soil Limestone NTT

Received: 08 October 2021 Accepted: 14 October 2021 Published: 10 November 2021 DOI: 10.32996/ijbpcs.2021.3.2.1 Cracking catalytic palm oil (CPO) into hydrocarbon fuel by saponification pretreatment has been carried out with bentonite and limestone-based catalysts. The catalysts used were Na-bentonite and Limestone NTT which were first analyzed using XRF, XRD, and SEM. Saponification pretreatment was carried out on CPO to facilitate the cracking process using a catalyst. The saponification product in the form of a mixture of soap and glycerol was then analyzed by DSC to determine the degradation temperature. Catalytic cracking is carried out in two stages, namely, the first stage hydrocracking at a temperature of 250-350C using a stainless steel reactor is the source of catalyst Fe / Cr. The resulting distillate was then cracked again using a Na-bentonite catalyst and a TKNTT catalyst. The resulting fuel is a hydrocarbon fuel which is confirmed from the FT-IR results which indicate the presence of long-chain hydrocarbon compounds. This data is also supported by the results of the GC-MS analysis which shows that the fuel fraction produced is mostly biogasoline. Where cracking using a Na-bentonite catalyst produces a biogasoline fraction of 61.36% and a biodiesel fraction of 38.63%, THAT produces a biogasoline fraction of 88.88% and a biodiesel fraction of 11.11%. The characteristics of the hydrocarbon fuels that have been analyzed show that the calorific value of combustion is 6101 cal/g which is determined using a bomb calorimeter, and the cetane index is 62 which is analyzed using CCI. Both types of hydrocarbon fuels have met the physical requirements that must be possessed by biogasoline fuel based on SNI standards. KEYWORDS

placed Indonesia as the main producer of CPO with a production volume of 23.9 million tons of CPO/year. This shows that Indonesia has enormous potential to produce biogasoline or other fuel oils derived from palm oil (Jatmiko, Qodri., 2021).
The process of making biofuel from palm oil has been carried out by various methods such as esterification, transesterification, and cracking. Cracking is the process of breaking a high molecular weight hydrocarbon compound into a lower molecular weight compound by breaking the carbon chain bonds (C-C). The cracking reaction is divided into 2, namely: thermal cracking and catalytic cracking. Thermal cracking or pyrolysis is a reaction to break the bonds of hydrocarbon compounds due to the influence of thermal (high temperature). The mechanism of the thermal cracking reaction is through the formation of free radicals in forming the final product. The catalytic cracking reaction is the reaction of cracking(cracking) using a catalyst material (heterogeneous catalysts) as the material is capable of accelerating the reaction rate to achieve equilibrium and produce a final product through the reaction of the carbonium ion formation mechanism. (S, Donatus. 2015). Catalytic cracking has advantages over the methods used to process triglycerides. Among them, the products of catalytic cracking are gas, organic liquid products, water, and soda. Organic liquid products include (Aldehydes, ketones, carboxylic acids, and hydrocarbons such as paraffin, olefins, and naphthenic) whose boiling points correspond to gasoline, kerosene, and diesel. Both reaction temperatures are lower than those of pyrolysis, and large molecules are broken down into simpler molecules through dehydration, dehydrogenation, deoxygenation, and decarboxylation (Jovas et al., 2015).
(Anando et al., 2016) have investigated the production of biogasoline from palm oil through a catalytic cracking reaction with a gamma-alumina catalyst and obtained the peak results of the compounds analyzed by GC-MS similar to the peaks of commercial gasoline and obtained straight-chain hydrocarbon compounds at C6-C11. Mancio et al., (2016) have done a catalytic thermal cracking of the crude palm oil at a pilot scale using a catalyst Na2CO3. This study produced a conversion of 60% and produced biofuel with an acid value of most rendah. Senyawa-hydrocarbons The resulting product has characteristics similar to petroleum diesel.
The latest research was also carried out by Friskila, S (2020) namely the use of palm oil into hydrocarbon fuels with Saponification Pretreatment through the cracking of CPO with Fe/Cr catalyst. In this study, a chromatogram with the largest area was produced for the compound 1-Dodecane (C12H24) which was equivalent to the fraction biodiesel.
Jonathan, H (2021) also conducted a similar study, in which Crude Palm Oil was cracked using Na-Bentonite and Fe2O3 as catalysts. From this research, the result is that there is a dominant compound which is a straight-chain hydrocarbon compound, namely 1pentadecane (C15H30).
The effect of pore size on catalytic cracking has been studied. (Sadramelli, M, S. 2016) has investigated the effect of catalyst pore size on n-octane catalytic cracking activity using ZSM-5, HZMS-5, and Hβ catalysts with small, medium, and large pore sizes. The selectivity of olefins increases with a decrease in the pore size of the catalyst. Another study also examined the effect of aluminum (Al) in the catalyst and concluded that a lower amount of aluminum (Al) in the catalyst resulted in higher olefin production, this was due to the slightly lower amount of aluminum (Al) in the acid site in the catalyst. the catalyst which results in higher selectivity for olefins. In this study, researchers will crack CPO by comparing the use of two catalysts, namely Na-bentonite and Al2O3 from limestone soil of NTT. Researchers want to compare the amount of conversion of CPO into biogasoline and biodiesel fractions produced on each catalyst.
The purpose of this study was to determine the characteristics of the fuel produced using Na-bentonite and TKNTT catalysts.
Over the centuries, fossil fuels have been used in many aspects of life, but these fuels are non-renewable and will eventually run out. The scarcity of fuel now makes people have to look for alternative energy sources that are easily renewable (renewable fuels), one of which is biofuel. In recent years, many developments have been carried out on raw materials for making biofuels from plants, especially oil palm, this is because this fuel is non-toxic and does not contain nitrogen and sulfur compounds. Palm stearin is a derivative product of palm oil which is solid at room temperature and can be used as a raw material for the production of biofuel(Chuckling and Ratnawali, 2014).
Alternative fuels (biofuels) can be produced from various varieties of renewable natural resources. Among them, triglycerides have a very important role and are compounds that are commonly found in vegetable and animal oils (Doronin et al.,2012). Several techniques have been studied to convert vegetable oils and animal fats into biofuels. One of the most promising techniques for producing alternative fuels from vegetable and animal oils is pyrolysis. Pyrolysis is also known as thermal cracking and catalytic cracking. (Xu et al.,2013).

Research methods
Preliminary analysis was carried out on the CPO samples to determine the value of free fatty acids. Then put 100 g of CPO sample into a glass beaker and then heated at a temperature of 90 o C then added 30 g of NaOH and then heated while stirring with a magnetic stirrer until the soap was formed. The soap was allowed to stand for 24 hours and then put into a stainless steel reactor and then heated on a gas stove at a temperature of 250 o C-360 o C for 2 hours while connected to a distillation device. The resulting distillate is accommodated. Each 100 mL of the resulting distillate was added with 5 g of Na Bentonite and 5 g of NTT lime soil. Cracked by heating on a gas stove at a temperature of 250-350 o C for 2 hours while connected to a distillation apparatus. The resulting distillate is accommodated. The resulting distillate was analyzed using GC-MS, FT-IR, and Calculated Cetane Index (CCI).
This research was conducted from March to May 2021 at the Laboratory of Inorganic Chemistry, FMIPA USU, Medan. Analysis of FT-IR and GC-MS performed in the laboratory of Organic Chemistry UGM. Analisa Calorimeter conducted at the Laboratory of Chemical Physics Research and Technology UGM. The DSC analysis was carried out in the laboratory Electron Microscope PTKI, Medan. The analysis was Calculated Cetane Index carried out in the PT. SUCOFINDO, Bekasi. XRD and SEM EDX analyses were carried out at the Physics Laboratory of the State University of Medan.

carried out the preparation of Limestone Soil Samples in NTT (TKNTT). TKNTT
samples were dried at a temperature of 100 0 C using an oven and then crushed using a pestle and mortar, filtered, and then characterized using SEM, XRD, and XRF.

Conversion of Palm Oil (CPO) into Fuel Biogasoline through Thermal Cracking Using a Catalyst Based Na-Bentonite and Limestone of Soil Limestone NTT
Put 50 g Bentonite into Erlenmeyer then add 200 mL 30% NaOH allowed to stand 6 hours then filtered using filter paper, and then heated in an oven at 105°C and then pulverized with a mortar and pestle, then filtered and then characterized using SEM, XRD, and SEM.

CPO cracking with NaOH pretreatment
weighed 100 g CPO, inserted into a glass beaker, added 30 g NaOH in technique then heated at a temperature of 90°C above the hotplate while stirring with a magnetic stirrer. After the soap is formed, then let stand for 24 hours. The resulting soap was analyzed using DSC and Bomb Calorimeter. The resulting soap is put into a stainless steel reactor and connected to reactor stainless steel with a condenser. Heated on a gas stove while measuring the temperature using a thermometer. The resulting distillate was accommodated in an Erlenmeyer flask until the last drop of the distillate was collected.

Cracking of CPO with Na-Bentonite
Measured 100 mL of CPO distillate then put into a reactor stainless steel and then added 5 g of Na-bentonite. It is connected to reactor stainless steel with a set of distillation equipment and then heated on a gas stove while the temperature is measured using a thermometer. The resulting distillate was collected using an Erlenmeyer flask until the last drop of the distillate was collected. The resulting distillate was characterized using GC-MS, FT-IR, and CCI (calculated cetane index).

CPO cracking with TKNTT
Measured 100 mL of CPO distillate then put into a reactor stainless steel and then added 5 g of TKNTT. The reactor is connected stainless steel to a set of distillers and then heated on a gas stove while the temperature is measured using a thermometer. The resulting distillate was collected using an Erlenmeyer flask until the last drop of distillate was collected. The resulting distillate was characterized using GC-MS, FT-IR.

Preparation Na-Bentonite Production of Conversion of Palm Oil (CPO) into Fuel Biogasoline through Thermal Cracking Using a Catalyst Based Na-Bentonite and Limestone of Soil Limestone NTT
Page | 6

Free Fatty Acid Analysis of CPO
The results of the analysis of CPO fatty acids were determined using the following calculations: Determination of free fatty acids of CPO samples was carried out 3 times analysis then the value of free fatty acids was determined from the average value. ALB levels in the CPO samples used in this study were 4.22%. ALB levels indicate the level of product damage due to the breakdown of triglycerides into glycerol and free fatty acids. A high acid number indicates that the free fatty acids present in vegetable oil are also high so that the quality of the oil is even lower (Winarno, 2004). According to widya (2015), There are various grades of CPO (Crude Palm Oil) that can be used as an alternative to raw materials, biofuel namely standard CPO (FFA < 5%), off-grade CPO (FFA 5 20%), waste CPO (FFA 20 70 Determination of free fatty acids can be carried out using the alkaline titration method (NaOH). In principle, this method analyzes free fatty acids based on the amount of NaOH used in the titration to form a pink sample color. This is in accordance with the statement of Maligan (2014) which stated that the principle of acid-base titration is the analysis of the amount of free fatty acids in a sample which is equivalent to the amount of base (NaOH) added in the titration which is marked by a change in the color of the sample to pink.

Conversion of Palm Oil (CPO) into Fuel Biogasoline through Thermal Cracking Using a Catalyst Based Na-Bentonite and Limestone of Soil Limestone NTT
Page | 8

Pretreatment of CPO with Saponification
The first step of this research is to perform cracking of CPO samples with saponification pretreatment. At this stage, a distillate will be produced. According to Friskilla's research (2020), the distillate used The resulting biodiesel fraction. Furthermore, the resulting distillate will be cracked using Na-Bentonite and TKNTT catalysts. At this stage, Palm Oil / Crude Palm Oil is reacted with NaOH base to form soap (salt of fatty acid triglycerides). Palm Oil Saponification Reaction produces soap (triglyceride fatty acid salt) based on the following reaction:  Thermal analysis with DSC on the results of CPO saponification in the form of soap is shown in Figure 4.2. This shows that there is a peak indicating the glass transition(Tg)at 94.45°C, crystallization peak at 413°C, peak melting(Tm)at 475.43°C, and a decomposition peak at 527.43°C Based on the data obtained, it shows that the temperature required for the process of cracking soap into fuel without using a catalyst is 527.43 o C. This data is in accordance with previous research (Supeno et al., 2021). The addition of a catalyst in the cracking process is needed to reduce the activation energy so that the temperature required for the cracking process can be lowered. CPO catalytic cracking process of saponification pretreatment results conducted in the temperature range 250-350°C. Determination of the cracking temperature was envisaged from the boiling point of biodiesel is similar to diesel fuel in the range of 270-350°C.

Catalytic Cracking CPO saponification results
This research does catalytic cracking in stages, where the results of catalytic cracking using a Fe/Cr catalyst against the saponified CPO will be carried out again by catalytic cracking using Na-bentonite and TKNTT catalysts.
During the cracking process, the CPO saponification products in the form of soap and glycerol will be converted into hydrocarbon compounds in the presence of a Fe/Cr catalyst from reactor stainless steel. Based on the results of research conducted by Supeno et al., (2021), catalytic cracking at this stage produces a biodiesel fuel fraction. In this study, the cracking process was carried out again using Na-bentonite and TKNTT catalysts, where biodiesel fuel would be converted into biogasoline fuel which was analyzed using GC-MS.
The catalytic cracking process occurs at a temperature of 250-350°C and is able to produce energy that causes excitation of electrons from the catalyst (Fe / Cr, Na-bentonite, TKNTT). These electrons will fill the empty orbitals of the carbon atoms that make up the long hydrocarbon chain until the orbitals are full and become saturated. At this time there will be a cracking process.
Pretreatment distillate catalytic cracking process CPO produce a yield of 77% calculated as follows: mass CPOsample = 100 g density of oil = 0.9 g / mL = the distillate obtained is then cracked back on heating 180-240°C using different catalysts namely Na-Bentonite and TKNTT so that the distillate is obtained as follows:

Analysis X-Ray Fluorescence (XRF)
The chemical elements in bentonite and limestone soils of NTT analyzed using XRF are shown in Table 4 Where the presence of these compounds is discussed further in XRD analysis.

Analysis of X-Ray Diffraction (XRD)
Na-Bentonite and TKNTT XRD diffractograms are shown in Figure 4.3. shows that the pillarization of bentonite with Na metal has been successfully carried out. However, there is a diffraction peak at 2 = 20.7 o ; 26.5 o ; and 28.2 o which is the diffraction peak of bentonite material (JCPDS No. 29-1499). This shows that there is still bentonite that does not react to form Na-bentonite (Naik & Meivelu, 2020).
Based on the results of XRF and XRD analysis, Na-bentonite indicates the presence of Quartz as the most dominant compound. Other crystalline phases such as Lime, Corundum, Hematite, and Ilmenite were identified as impurities. diffraction peaks Quartz with a hexagonal structure are at 2 = 20.

Analysis Scanning Electron Microscope (SEM)
analysis of Na-bentonite catalyst morphology and TKNTT using SEM with a magnification of 500 and 2000 x shown in Figure 4  Na-bentonite micrographs have surface characteristics that appear as groups of agglomerated particles consisting of layers with smooth surfaces that are stacked on top of each other. From Figure 4.4 a, it can be seen that there is a porous character and the catalyst crystals are sphere-like crystals. Compared to Figure 4.4 b, the TKNTT catalyst has a rougher surface. This is assumed to come from the combination of CaCO3, CaO, and Ca(OH)2 which has a surface structure like a cube (cubic).

Analysis of Gas chromatography-mass Spectrometry (GC-MS)
Alternative fuel (biofuel) produced from the cracking process using Na-bentonite and TKNTT catalysts then analyzed using the GC-MS instrument to analyze the fuel fraction contained in the sample and its constituent compounds. The chromatogram of the fuel produced from the catalytic cracking of the CPO distillate is shown in the figure below. The chromatogram in Figure 4.6 shows that there are 44 compound fractions identified in the fuel resulting from catalytic cracking using a Na-bentonite catalyst. The results of the GC-MS analysis showed that there were 5 constituent compounds with the highest peaks, which are summarized in Table 4.5.

Page | 14
The chromatogram in Figure 4.7 shows that there are 36 fractions of compounds identified in the fuel resulting from catalytic cracking using TKNTT catalyst. The results of the GC-MS analysis show that there are 5 constituent compounds with the highest peaks which are summarized in Table 4.6 The results of the analysis of the fuel from the catalytic cracking of the CPO pretreatment distillate using the Na-bentonite catalyst showed that the biogasoline and biodiesel fractions were 61.36% and 38.63%, respectively. Meanwhile, using the TKNTT catalyst produced biogasoline and biodiesel fractions of 88.88% and 11.11%, respectively. Thus, in this study, the catalytic cracking of the CPO pretreatment distillate has the potential to produce more gasoline fractions than biodiesel fractions. The study of Supeno et al., (2021) produced fuel with a major fraction in the form of biodiesel from CPO using a Fe/Cr catalyst. Likewise, research conducted by Hutabarat (2021) conducted catalytic cracking using Na-Bentonite on saponified CPO to produce biodiesel fuel fraction. In this study, catalytic cracking was carried out in stages, where the results of the catalytic cracking using a Fe/Cr catalyst against the saponified CPO will be carried out again by catalytic cracking using Na-bentonite and TKNTT catalysts. From these data, it can be concluded that the catalytic cracking of saponified CPO produces a biodiesel fuel fraction, while the second catalytic cracking stage using Na-bentonite and TKNTT catalysts produces a major fraction of fuel in the form of gasoline.

Analysis of Bomb Calorimeter and CCI
Bomb calorimeter analysis was carried out to test the calorific value with the aim of knowing the number that states the amount of heat generated from the combustion process of a certain amount of fuel with oxygen. The standard calorific value of fuel based on the SNI-04-7182-2006 standard is 10,498 BTU/lb or about 5,832 cal/g. In this study, the calorific value of biodiesel combustion was 6101 cal/g using a Na-bentonite catalyst. Thus the fuel produced meets the Net Calorific Value according to the standard.
The cetane number (CN) is used to describe the ignition quality of diesel fuel. The ignition quality of diesel fuel can also be calculated using the Cetane Index (CI) method (EN ISO 4264, ASTM D 4737). The cetane number of a fuel is influenced by the elements contained in the fuel, such as the element carbon which is a source of combustion energy (Supeno et al., 2021). The standard cetane index that biodiesel must have is >45. Based on the CCI test results, the cetane index value was 62 using Nabentonite catalyst. Based on the data obtained and summarized in Table 4.5, it can be concluded that the fuel obtained in this study can be used as an alternative fuel candidate in the form of biogasoline that has met the specified standards.

Conclusion
1. The results of XRD and XRF analysis show that Na-bentonite is mostly composed of Quartz (SiO2) minerals, while TKNTT is mostly composed of CaCO3 minerals. The morphology of the catalyst analyzed using SEM showed that both catalysts had a large and porous surface. Where the Na-bentonite catalyst appears as crystals that are shaped like spheres (spherelike crystals) while the TKNTT catalyst is in the form of a cube (cubic). 2. In accordance with the results of the FT-IR and GC-MS analysis, it can be concluded that the fuel fractions produced are biogasoline and biodiesel fractions. The biogasoline fraction is 88.88% (TKNTT) 61.36% (Na-Bentonite) and the biodiesel fraction is 11.11% (TKNTT) and 38.63% (Na-Bentonite). combustion was 6101 cal/g determined using a bomb calorimeter, and a cetane index of 62 which was analyzed using CCI. Both types of hydrocarbon fuels have met the physical requirements that must be possessed by biogasoline fuel based on SNI standards.