Recycling Waste Lubricants with Different Types of Base Oil into Low Sulfur Fuel with Two Stage Distillation Pyrolysis Process

The intent and purpose of the research is to improve fuel performance by recycling waste lubricants into low sulfur fuel, using waste lubricants made of various types, namely mineral, semi-synthetic, full synthetic, and mixtures from different sampling sites, with the scope of lubricant waste coming from motorcycles. Recycling waste lubricants is chosen in 2 stages, to get purer fuel and better fuel performance, it is called a distillation pyrolysis process. The advantage of using this distillation pyrolysis process is that it does not use high temperatures, and is cheap and fast. Waste lubricant recycling using a two-stage distillation pyrolysis process produces a fuel with a sulfur content that decreases by 61.98 %wt -68.61%wt in stage I and 66.32 %wt - 70.66 %wt in stage II for waste lubricants with four different base oil. Thus, proving that the two-stage distillation pyrolysis process can reduce sulfur content and can also improve fuel performance at the characteristic values of several other chemical properties.


Introduction
The supply of fossil fuel reserves is dwindling in various parts of the world [36].Lubricant is the most important part of the vehicle but has the disadvantage of allowing waste when its function is lost [22].Therefore, B3 waste creates many problems, When the waste lubricant is not used and disposed of into the environment [37].The process involves organic gas, lubricating fluid, and carbon residue which is called pyrolysis [32].B3 waste management in Indonesia has been regulated in Law Number 32, 2009 -Environmental Protection and Management and Government Regulation No 22 of 2021.In General, Provision Number 69, Appendix IX, waste code B105d, with hazard category no 2. Waste lubricants are included in hazardous and toxic materials [41].Based on research from Coles et al., 2011, the advantages of various base oils are that they consist of fully synthetic base oils that make them stable at high temperatures so that the evaporation rate becomes low.The advantages of mineral and semi-synthetic base oils compared to full synthetic base oils are that they are cheaper, and the quality is quite good [1].Lubricant waste is one of the wastes generated by workshops [40], classified as industrial waste where this workshop waste contains COD, metal lead (Pb), phosphate (PO4), and lubricating oil [43].Environmental damage can be caused by workshop activities that produce lubricant waste [38].Based on research by Maceiras et al., 2017, that the most suitable and effective method for treating waste lubricants is pyrolysis technology, because it does not require high temperatures and can take place quickly [25].Pyrolysis technology is usually used to convert waste lubricants into energy using high heat [33].Pyrolysis is a thermal process that can heat and decompose substances at high temperatures (300 °C-1000 ºC), when in the environment and this thermal process is carried out to convert waste into other products that are more 1257 (2023) 012003 IOP Publishing doi:10.1088/1755-1315/1257/1/012003 2 useful [34].Pyrolysis distillation of waste lubricants is the best technology for producing diesel fuel [36], can be done by distillation pyrolysis process [27].Waste conversion engine lubricant into diesel fuel using distillation pyrolysis technology has a positive impact on the environment and atmosphere, also has an economic efficiency value [3].

I.1. Base Oil, Lubricants dan Waste Lubricants
Base oil is a determinant of pour point, the purity of the constituents of various kinds of sulfur lubricants, nitrogen, and aromatic compounds [24].The advantages of base oil according to Coles et al., 2011 [26] are according to various base oils, namely that full synthetic base oil is stable at high temperatures so that the evaporation rate becomes low.The advantage of mineral and semi-synthetic base oils compared to full synthetic base oils is that they are cheaper and of fairly good quality.Waste lubricant is one of the wastes generated by workshops [39], classified as industrial waste where this workshop waste contains COD, metal lead (Pb), phosphate (PO4), and oil grease (OG) [43].However, there are risks posed by used lubricant contamination [28], namely one liter of waste lubricant is estimated to damage millions of liters of fresh water from groundwater sources, and there has been an increase in engine fuel requirements.caused by increased transportation activities, the number of industries, and power generation centres in various regions in Indonesia [35].Workshop activities produce waste lubricant which can hurt the environment [38].

I.2. Analysis of the Distillation Pyrolysis Method for Fuel
The most suitable and effective method for treating waste lubricants is pyrolysis technology [36] because it does not require high temperatures and can take place quickly [25].The conversion of waste lubricants into energy using high heat is carried out using pyrolysis technology [33].Pyrolysis distillation of waste lubricants is the best technology for producing diesel oil [36] and can be carried out by distillation [27].The conversion of waste lubricants to be used as diesel fuel using the pyrolysis distillation process has a positive impact on the environment, atmosphere and has economic value [3].The conversion of waste engine lubricants into diesel fuel using distillation pyrolysis technology has a positive impact on the environment and atmosphere and has economic value [3].Studies on the processing of waste lubricants into fuel have been carried out by several researchers, for automotive waste lubricants with mineral-based ingredients it has been studied by O. Arpa et al., 2010.The processing of industrial automotive lubricants has been studied by Bhaskar et al., 2004.Maceiras in 2017 used specific test samples on engine waste lubricants, both automotive and industrial engines [36], and hydraulic waste lubricants, and cutting oil processing used by Nerin et al. in 2000.

Equipment and Material
Use of a distillation reactor with the Labsco brand, UK.The distillation flask during the pyrolysis process is made of stainless steel with a volume of 150 ml, with a burner heater that comes from the heat of combustion using electricity and is equipped with a conductor and temperature recorder in the form of a thermometer in the distillation pyrolysis process.The pyrolysis reactor used to show on Figure 1 as follows: The distillation reactor consists of parts that have their functions in the pyrolysis process, namely: (1) Heat source from electricity, (2) Heater (3) Distillation Flask/Distillation Kolb: The container to hold the sample is made of stainless steel with the size height: 25 cm, ball diameter: 7 cm, main pipe diameter: 1 mm, condenser pipe diameter: 0.5 mm, ball thickness: 2 mm, main pipe thickness: 2 mm, condenser pipe thickness: 2 mm and volume: 150 ml. ( 4) Thermometer ( 5) Heat Resistant Boards ( 6) Shield ( 7) Bath Condenser (8) Graduated Cylinder (9) Support and blotting paper.
The material needed is waste lubricants originating from motorcycles, namely waste lubricants made of various types, namely mineral, semi-synthetic, full synthetic, and mixtures waste.Waste lubricant as a mixed test material is waste lubricant obtained from motorcycle repair shops.Wasted lubricants with two-stage distillation pyrolysis process was carried out at the B3 Waste Laboratory at the Bandung Institute of Technology.Pyrolysis Distillation stages I and II were used at a temperature of 400 ± 5 ºC.The volume of pyrolysis oil produced was 95% ± 5% for each pyrolysis product using 100 ml of waste lubricant as a test material.The results obtained, carried out characteristics in the form of physical and chemical properties.Physical and chemical character tests of pyrolysis oil/fuel were carried out 3 times.

Methodology
A sampling of waste lubricants as a test material was carried out in large motorcycle repair shops in the Jakarta, Bogor, Cilacap, and Surabaya areas (Indonesia).Waste lubricant as a mixed test material is not special lubricatns with the type of base oil used and its API Service, while waste lubricant samples made from mineral base oil, semy synthetic base oil, and fully synthetic base oil are made on a laboratory scale with confidential formulation (80% -90% base oil + 10% -20% additives) belonging to PT Pertamina Lubricants.The waste lubricant called mineral, semy synthetic and fully synthetic used as a test material is waste lubricant obtained from an artificial formulation and is the result of a trial run of lubricants on motorbikes with a usage time range of 2000-4000 KM using heating and stirring at a temperature of around 70 ºC.Waste lubricant is obtained from the use of lubricants in a few motorcycles of the type of automatic and manual.Pretreatment of waste lubricants as test material in the form of filtration, homogenization, and dewatering.The verification sample was tested using a distillation pyrolysis reactor and distillation cold according to the distillation verification test method using ASTM D 86.The pyrolysis process was carried out in 2 stages, carried out on all waste lubricants as test materials with different base oil at the same variable temperature, pressure, and indicator of the final condition of the process.Pyrolysis oil was obtained, then carried out the characterization of the lubricant's properties.The physical and chemical characterization that was carried out was colour ASTM, viscosity kinematic at 40 °C, sulfur content (for waste lubricants), sulfur content (for pyrolysis oil), phosphor content, water content, acid number, acid number, sediment content, flash point COC, micro carbon residue testing, pour point, copper strip corrosion, density at 15 °C, ash content, flash point PMcc, cetane index and recovery -distillation.

Physical and Chemical Characterization of Waste Lubricant as Test Material
The results of the physical and chemical tests of waste lubricant as a test material can be seen in Table 2.The ASTM color values for the four types of waste lubricants with different base oils are the same, namely >8.0.If the color range of a particular fuel is known, color can also indicate the presence of potential hazards from other products.The kinematic viscosity values of the four waste lubricants are 58.24cSt -72.05 mm 2 /s.Viscosity can affect pollutant emissions and affect quality because it can indicate the resistance of a liquid to flow.The smallest sulfur content was found in mineral lubricant waste and the largest was semi-synthetic lubricant waste, as well as the smallest phosphorus content, which was found in mineral lubricant waste, but the largest was in mixed lubricant waste.The quality of refined petroleum products can be determined by the sulfur content present.Waste lubricant certainly contains sulfur compounds, sulfur compounds remaining in processed waste lubricants can corrode various metals, variation of the effect according to the type of chemical sulfur compound contained.The effect can vary according to the type of chemical sulfur compounds present.The phosphorus test is primarily intended for use at production sites to monitor additive elements in lubricants.The water content in mineral lubricant waste is the largest compared to the water content in other types of waste lubricants, while the acid value for full synthetic waste lubricants has the highest value.In lubricating oils, the presence of moisture can cause corrosion and premature wear, increased loads resulting in reduced lubrication and filter clogging, and the undesirable effect of supporting the growth of harmful bacteria.Used lubricants may contain acidic constituents present as additives or degradation products formed during use such as oxidation products.
Guidelines in controlling the quality of lubricating oil formulations and can be used as a measure of degradation of the lubricant used can be estimated by acid number.The sediment content of the four types of lubricant waste used as test materials has almost the same value.The sediment of crude oil and fuel oil is very important for operations of refinery and buying and selling processes, while the flash point values of the four types of waste oils have sufficient value.Varied, flash point is used to count and describe the property of a substance, product, or test flame under reasonable conditions.The MCRT content is 0.63 -1.13% w/w, while the pour point value is -33.0 ºC for four different types of waste lubricants.As an approximation of the test substance to form carbon-type precipitates under the degradation conditions used in the test method the carbon value is used.The pour point of lubricating oil is the lowest temperature index used for applications when there is a sudden change in temperature.
Copper plate test value is 1B for four waste lubricants, copper strip corrosion test is designed to assess the relative corrosivity of petroleum products.Density of the four types of waste lubricants have relatively large different values, because density is a physical property that can be used to characterize the light and heavy fractions of petroleum products.The ash content in the waste lubricants from the four types is relatively small, which means that the amount of ash-forming material present in refined petroleum products can provide information about whether the product is suitable or not suitable for use in a particular application.Ash can be produced from oil or water-soluble metal compounds or foreign solids such as dirt and rust.).The range of water content of stage II pyrolysis oil from four types of waste lubricants with different base materials as test materials was 0,0110 %wt -0,0247 %wt (110 ppm-247 ppm), the range of acid number of stage II pyrolysis oil from four types of waste lubricants with different base materials as test materials was 0,131 mg KOH/g -0,443 mg KOH/g.The color of the fuel varies depending on the crude oil and the refinery's processing method as well as the use of dyes to color fuel [23].Fuel with the high viscosity value causes it to not easily flow in the engine and causes system crash.While diesel fuel with a low viscosity value as well does not provide adequate injector lubrication [36].
An important consideration in the selection of fuel is sulfur.Sulfur is a combustible element in fuels that produces energy.The result of combustion is sulfur dioxide (SO2) and sulfur in a free state which is an environmental pollutant.Sulfur meets water vapor in hot conditions to produce sulfuric acid and free sulfur, both of which contribute to acid rain [2].The presence of water in diesel fuel is an unwanted material in fuel because it affects its quality [30].The water content in fuel can be classified into free water, emulsified water, and dissolved water.The presence of air in the fuel causes the fuel injectors to crack, damage or explode.The Acid Number shows a tendency to corrode metals, because the organic acids present in the fuel cause the fuel to be corrosive.There is no limit to the acidity value.However, this parameter is important to test, because a high acidity value can reduce fuel stability and cause corrosion or the formation of deposits.The cetane number measures how quickly or slowly the ignition of diesel fuel occurs.The cetane index increases at the intervals when the fuel is injected and the time it starts to burn and decreases in the engine.Ignition delays can lead to difficulty starting the engine, poor fuel economy, and loss of power and engine damage [36].The flash point is the ease with which a test object forms a flammable mixture with water under reasonable conditions.Flash Point is one of several characteristics that must be considered in assessing the overall flammability hazard of a substance.The flash point can indicate the possibility of the presence of a highly volatile and flammable material under relatively non-volatile conditions or a non-flammable material.For example, an abnormally low flash point in engine oil could indicate fuel contamination.When the flash point has been reached, the fuel vapor may stop igniting when the ignition source is removed.The flash point is used as a character for liquid fuel [3].Density is an important test of fuel, because since the injection of fuel in the system, pumps and injectors, the amount of diesel must be adjusted precisely to produce optimal combustion [29].Density is highly dependent on the type of fuel and the purification step [42].A higher distillation temperature will provide fuel combustion efficiency and will improve engine performance.

Sulfur Content in Stage I Pyrolysis Oil and Stage II Pyrolysis Oil
Figure 4 shows that the two-stage distillation pyrolysis process produces pyrolysis oil with a lower sulfur content.
Figure 4 Sulfur Content of Waste Lubricant and Pyrolysis Oil In this study, it can be seen that the two-stage distillation pyrolysis process can reduce sulfur content greater than the sulfur content of single-stage distillation pyrolysis, namely in the range of 1,044-1,328 ppm, and the amount is very significant when compared to the sulfur content originating from waste lubricants with the range of 2,992 ppm.-4,230 ppm.The sulfur content of pyrolysis oil produced in the 2-stage distillation pyrolysis process indicates that the distillation pyrolysis process can produce lower sulfur products, namely in the range of 878 ppm -1,314 ppm.However, compounds such as sulfur, chlorine, nitrogen and bromine found in waste lubricants/pyrolysis oil are the most important factors that make waste lubricants/pyrolysis oil difficult to recycle for fuel [36].

Reduction of Sulfur Content, Acid Value, and Water Content in Pyrolysis Oil
Table 3 shows the percentage of decline in the value of the 3 test properties which are chemical characteristics after pyrolysis oil underwent a 2-stage distillation pyrolysis process.The conversion of used engine lubricants into fuel like diesel using a pyrolysis distillation process has a positive impact on the environment and atmosphere and has economic value [3].Waste lubricants contain metals and other contaminants besides metals [40].It even contains residual additives such as phenols, and polyaromatic hydrocarbons as well as zinc, chlorine, and phosphorus [31].

Conclusion
The number of motorised vehicles in 2020 based on data sources from the Indonesian Central Bureau of Statistics, motorcycles occupy the most types of vehicles, reaching 84.49%wt of the total number of motorcycles in Indonesia.The value of sulfur content in waste lubricants is 2,992 ppm -4,230 ppm.The range of sulfur content of stage I pyrolysis oil from four types of waste lubricants with different base materials from the test material was 0.1044 %wt -0.1328 %wt (1.044 ppm -1.328 ppm).The range of sulfur content of stage II pyrolysis oil from four types of waste lubricants with different base materials from the test material was 0.0878 %wt -0.1314 %wt (878 ppm -1.314 ppm).Waste lubricant recycling using a two-stage distillation pyrolysis process produces a fuel with a sulfur content that decreases by 61.98 %wt -68.61 %wt in stage I and 66.32 %wt-70.66%wt in stage II for waste lubricants with four base oils.After going through the second stage of the distillation pyrolysis process, the fuel/pyrolysis oil produced does not fully meet the physical and chemical specifications required as diesel fuel which is generally used in Indonesia.

Figure 1
Figure 1 Distillation Pyrolysis Reactor to be Used.

3. 2
Physical and Chemical Characterization of Distillation Pyrolysis Stage I and Stage II Figure 2 (a) and Figure 2 (b) show the results of physical and chemical tests of phase I mineral, semisynthetic, full synthetic and mixed pyrolysis oil.

Figure 2 (
Figure 2 (a) Properties of Stage I Pyrolysis Oil

Figure 3 (
Figure 3 (a) Properties of Stage II Pyrolysis Oil

Table 2
Physical and Chemical Tests of Waste lubricant

Table 3
Sulfur Content, Moisture Content, and Pyrolysis Oil Acid NumberTable3shows the percentage reduction in sulfur content, water content, and acid value in pyrolysis oil.The range percentage reduction in sulfur content in pyrolysis oil with different types of base material is 66.31 % wt -70.66 %wt.The range percentage reduction in water content in pyrolysis oil with different types of base material is 75.88 %wt-87.33%wt and the range percentage reduction in acid number in pyrolysis oil with different types of base material is 60.52 %wt -92.75 %wt.