Mass balance of palm waste energy potential in palm oil processing in South West Aceh, Indonesia

The process of land clearing, tillage, and planting in plantations has environmental impacts. The use of fertilizers, both organic and inorganic, contributes to potential emissions during land preparation (262 kg/cycle), tillage (236 kg/cycle), and planting (165 kg/cycle). Land preparation has the highest emissions due to increased fuel consumption. Planting oil palm seedlings aged 1, 2, and 3 years requires significant water (5,160,063.496 tons/cycle, 5,222,991.444 tons/cycle, and 5,411,774.030 tons/cycle, respectively). Outputs in years 4-7 include groundwater use (5,710,654.467 tons/cycle), 12,750 tons of fresh fruit bunches (FFB) per cycle, 12,878 tons of palm fronds and leaves per cycle, and 19.62% evapotranspiration. In years 8-10, FFB production reaches 24 tons/cycle, with 12,878.79 tons/cycle of fronds and leaves, and 19.63% evapotranspiration. In years 11-14, FFB production is 26 tons/cycle, with 6.435 tons/cycle of fronds and leaves. The water requirement remains at 80.37%. For oil palm aged >19 years, FFB production decreases to 18 tons/cycle, with fronds and leaves remaining the same. Electrical waste energy (E) generated by 2050 totals 7,343,834.558 GW, increasing from 2016-2032 and plateauing from 2033-2050. Factory energy needs (Ep) at 20% power plant efficiency are 1,468,766.912 GW, while waste-derived energy (P) is 167.667 GW.


Introduction
The research approach used is descriptive quantitative research describing the state of the object under study according to the facts in the field (existing facts), concrete, observable and measurable, meaning revealing all studies in the field on the utilization of palm oil waste shell, fiber, empty fruit bunch and liquid waste (palm oil mill effluent).For POME, a study based on methane gas (CH4) produced in 1 m should be considered 3 CH4.This approach study should refer to the biomass calorific value [1] [2] [3] [4] [5] as well as the conversion value of each waste [6] [7].
The production of fresh fruit bunches (FFB) is the raw material for the processing of FFB to produce crude palm oil (CPO), palm kernel oil (PKO), side waste in the form of solid and liquid POME (palm oil mill effluent) has a large amount and can disturb the environment [8] [9], and unutilized or liquid waste resulting from the accumulation of palm waste [10], increasing the yield of crude palm oil [11].In the actual (exiting) conditions, the processing process of producing palm oil is very energy intensive, and the need for water in processing produces solid waste and liquid waste.The waste produced is in the form of solid waste of oil palm empty bunches.fiber.and shells.and POME liquid waste [12] [13].Palm oil process waste (biomass) generated by palm oil mills can be used to support industrial sustainability.One of the alternative energy in increasing the utilization of waste so that it becomes efficient that has economic value.The energy conversion process of oil palm fresh fruit bunches in the process of producing palm oil (CPO) requires energy.both electrical energy.water and other process materials.
The utilization of biomass as a means to facilitate sustainable industrial development is of paramount significance.This phenomenon is prompted by the correlation between the cost of fossil fuel energy and its natural abundance.Biomass refers to organic matter that is produced during the process of photosynthesis, which can exist in the form of either usable goods or residual waste materials.Biomass, together with its byproducts, possesses the potential to serve as alternate sources of energy.Additionally, exploring alternate approaches to waste management can contribute to the promotion of sustainability by using trash as a renewable resource [14] [15].So this technology is needed to be utilized for future energy interests.
Agro-industry of sustainable oil palm plantations must apply the concept of utilization of waste generated (close system production) and the application of cycles during the production process.Utilization of oil palm waste empty palm bunches, and fiber waste to plantations as plantation mulch in maintaining soil fertility [6], as well as a cycle of reducing the use of inorganic fertilizers.Waste can act as fuel for mill boilers, electricity for remote mills [16], conversion of waste into valuable products [17] [18] [19].and regional, national and international palm oil industry development models for palm oil waste bioenergy development [18] [20] [21].
The process of processing palm fruit bunches begins with harvesting palm fruit in the plantation.weighing palm fruit.entering the shelter and ending at the processing process which is pulled by a lorry to begin processing at the processing stations.The process takes place in the zone of each FFB processing station.the process takes place at the sterilization station.stripping / thresser.digester.pressing countinous septling tank (CST), sludge tank, sludge separator tank.Back to CST. then oil purifier, vacuum dryer.and finally in the crude palm oil (CPO) and palm kernel oil (PKO) storage tank.The palm kernel oil (PKO) process starts with pressing, depericarper, nut cracker, kernel dryer, and PKO kernel tank.In general, wastes generated from these two processes and reused to the field as well as the combustion process for power plant boilers [22] [23].As well as the waste water treatment (WWT) process for palm oil mill liquid waste (POME) into biogas that produces methane gas (CH 4 ) for the benefit of electrical energy in an integrated and planned manner that can be utilized [17] [24] [25].Optimal utilization of residual/waste materials is very beneficial for all waste utilization actors.Therefore, it is necessary to analyze the material and raw material mass flow (input and output) to create a potential utilization of the waste generated for all processes that occur in the palm oil mill.
This study formulates a model of FFB processing in palm oil mills and raw materials to estimate energy production and the use of inorganic and organic fertilizers in the field.The energy produced by the waste is expected to generate electrical energy for the use of boilers to replace petroleum (diesel and gasoline) for processing in palm oil mills.Primary and secondary data obtained came from the data of palm oil mill companies that have processing plants and related parties of government agencies, and private plantation companies and oil palm plantation farmers.Mass flow analysis is limited to data available at plantation companies that own plantations and FFB processing mills in 2019.
The population in this study is all palm oil mills and companies in the South Barsela region, the population to be targeted is 16 palm oil mills and companies that have factories and plantations, as well as observations or observations at companies and palm oil mills.For data collection techniques include primary data from direct field observations and secondary data from company data conducted research.The company's primary data through company management, as well as research variables including data on the number of oil palm plantations, the number of palm oil mills, the amount of capacity and FFB production, the amount of fiber waste (fiber), shell (shell), empty fruit bunch and 3 liquid waste (palm oil mill effluent), data on the specifications of the factory power plant used.

Quantitative Analysis and Mass and Energy Balance of Palm Oil Waste Energy Potential
Palm oil mill processing is carried out at palm oil mills that have a processing capacity of 23, 30 and 60 tons per hour-1 in 16 palm oil mills in the South West Aceh (Barsela) region.According to [26] the capacity of FFB/ton processed will produce 23% TKKS, 21% oil and 22% mud, the remaining water 12% endoscarp (6%), kernel (5%) and fiber (22%).The processing process of 30 tons per hour and 60 tons per hour in factories located in the Barsela region will produce solid waste and liquid waste as potential energy to be developed in this region as alternative energy for potential electrical energy [27] [28] [7] sourced from waste generated from the palm oil processing process.This energy sustainability will affect the need for electricity sourced from waste, as well as the fulfillment of electrical energy for electricity continuity in Barsela.
The waste energy produced can be surplus energy.The existence of this surplus energy can be evaluated using the following equation: The variable EP represents the energy consumption associated with the palm oil mill process (POM) or the quantity of electrical energy supplied to the PLN grid system.The symbol η denotes the overall efficiency of the power generation process, which is currently at 20%.Additionally, the variable E represents the energy content of palm oil waste, including TKKS, fiber, and shell.The electrical energy requirements of the palm oil mill are met by the utilization of oil palm empty fruit bunch (EFB) waste, assuming a temporal progression of power production.
The energy content of by-products is calculated based on the heating value of each component.The total energy content is calculated by multiplying the mass of the product by the heating value of the component.

Mass and Energy Balance
The determination of mass and energy balance is predicated upon the fundamental principle of conservation of mass and energy.The principle of conservation of mass and energy posits that the total amount of mass and energy in a closed system remains constant over time, with no creation or destruction occurring.However, it is possible to convert them into alternative formats.Mass and energy balance never involves chemical reactions, it involves the FFB going through a series of processing processes sterilization.stripping/thresser.digester.pressing countinous septling tank (CST).sludge tank.sludge separator tank.Return to CST. then oil purifier.vacuum dryer.and finally in the crude palm oil (CPO) and palm kernel oil (PKO) storage tank.For the palm kernel oil (PKO) process starts pressing.depericarper.nut cracker.kernel dryer.and PKO kernel tank.
The basic mass balance process used is 1 ton of FFB, it can be calculated the mass balance balance based on the process of 30 tons of FFB.To calculate the mass balance, the following mathematical equation can be used:  =  (4) Note: minput = mass input (kg) moutput = mass output (kg) The assumptions employed in the computation of the energy balance are as follows: The energy input to the process consists of power and fuel, while the energy output is in the form of carbon emissions.The flow in both the inlet and output processes is characterized by one-dimensional behavior.The concepts of kinetic energy and potential energy are disregarded.
In all processes involved in the production of crude palm oil (CPO), palm kernel oil (PKO), solid waste, and liquid waste, a comprehensive analysis of mass and energy balance is performed.Mass and energy balance analysis is conducted in several processes, including sterilization, stripping/thresser, digester, pressing continuous septling tank (CST), sludge tank, sludge separator tank, oil purifier, vacuum dryer, and storage tank.For PKO, the mass and energy balance goes through several stages including; pressing.depericarper.nut cracker.kernel dryer.and kernel tank [32].The use of inputs to the life cycle of oil palm is preferred to the use of fertilizers, herbicides, pesticides and water needs for oil palm plants during the maintenance process until the harvest period which can produce carbon emissions (CO2eq) during the process until the replanting period [33] [34].

Energy Balance in Each Process Station
The energy balance in the station process is calculated based on the total fuel during the process and the resulting carbon emissions (CO2eq) [16] [35] [36] [37].The potential energy generated from each category of solid and liquid waste.Liquid waste can be estimated based on the potential methane gas produced in each category of waste that has been converted in units of kWh.

Potential Methane (CH4) generated from Wastewater
The energy potential of wastewater is determined by the utilization of anaerobic wastewater treatment methods.The effluent from the treatment process has a biochemical oxygen demand (BOD) ranging from around 25000 to 29000 mg L -1 (average 27,000 mg L -1 ) [38] [39].According to empirical findings, it is important to eliminate a biochemical oxygen demand (BOD) value of 27,000 mg L-1 (equivalent to 27 kg/L) in order to ensure the safe release of wastewater.According to [40], the highest achievable methane (CH4) production per kilogram of biochemical oxygen demand (BOD) eliminated is 0.6 kilograms of CH4 per gram of BOD.The estimation of methane gas generated from wastewater is conducted through the utilization of equation 5:
Based on equation ( 5), the potential methane gas produced per year for the observed biogas can be estimated.The estimation of energy potential can be derived by assessing the methane gas potential produced from the palm oil mill effluent (POME).Equation 6is utilized to determine the electrical energy output from the potential biogas by considering the calorific value of methane gas: = [4  1.17]    0.35 The potential energy values obtained from the calculations are expressed in electrical potential per ton of biomass (kWh/ton biomass).

Mass balance model of the Palm Oil Processing Process
The processing of palm fruit bunches begins with the harvesting of the palm fruit in the plantation.Weighing of the FFBs, then they enter the storage area and end up in the processing area where they are pulled by lorries to begin processing at the processing stations.The process takes place in the zone of each FFB processing station.The process takes place at the sterilization station, stripping/thresser, digester, pressing countinous septling tank (CST), sludge tank, and sludge separator tank.Back to CST, then oil purifier, vacuum dryer, and finally at the crude palm oil (CPO) and palm kernel oil (PKO) storage tanks.
The palm kernel oil (PKO) process starts with pressing, depericarper, nut cracker, kernel dryer, and PKO kernel tank.In general, the wastes generated from these two processes are reused in the field as well as the combustion process for power plant boilers [22] [23], and the waste water treatment (WWT) process for POME into biogas which produces methane gas (CH4) for the benefit of electrical energy in an integrated and planned manner that can be utilized [17] [24] [25].Optimal utilization of residual or waste materials is very beneficial for all actors of waste utilization.Therefore, it is necessary to analyze the material and raw material mass flow (input and output) to create a potential utilization of the waste generated for all processes that occur in the palm oil mill.
The process of processing palm oil (CPO) with a capacity of 30 tons per hour -1 applies the principle of mass flow of input to produce output.The application of material inputs used is inseparable from the process at each station to produce palm oil with good yields.The process of processing FFB to produce palm oil must go through the stages of the process with water energy material.electricity to be able to produce palm oil.These processes are interconnected between each station.because the output at one station will be the input at another station.This process continues for 20 hours per day 25 days per month and 300 days a year to process 30 tons of FFB per hour to produce solid waste and liquid waste [41].The accumulation of the processing process uses electricity to drive turbines or boilers using diesel or petroleum which can cause pollution to the air.the formation of the greenhouse effect (Global warning Potential).The formation of CO2eq carbon emissions (CO2.NOx and CH4) [35] [42] [36], to the air around processing plants in plantation companies.The mass and energy balance model used to produce Crude Palm Oil (CPO) or good palm oil is found in the processing process of boiling (sterilizer).stripping (striping/thresher). pulp removal (digester).pressing.clarification or initial purification (countinous settling tank).sludge tank.sludge separator tank.oil purifier.vacuum dryer.and palm oil tank (oil CPO tank/storage CPO tank).

Potential Palm Waste in the Boundary Cradle to Grave System
The potential of FFB processing to produce palm oil at each process station is 30 tons; 60 tons per hour -1 produces solids, liquids and gases that are lost due to the process.At each process station such as stripping, depericarper, Hydrocyclone produces waste that has the potential for energy such as TKKS waste (stipping), fiber (depericarper), and hydrocyclone.The shell (hydrocyclone) has a compound composition for each process that takes place.
The process of processing 30 tons of FFB per hour to the waste generated, the type of waste generated from the process of striping, depericarper and hydrocyclone stages respectively TKKS, fiber and shell.The amount of waste generated is 8,092.27TKKS, 5,348.17fibers and 1,939.76shell [32].For more details can be seen in Table 1.Source: [32] Table 1 shows the dominance of oil palm empty bunches of 16,801 kg h -1 , fiber of 10,556.37 kg h -1 and shells of 3,653.47 kg h -1 .Percentage comparison, TKKS (28%), fiber (17.61%), and shell (6.06%).According to [14] has conducted research on palm oil solid waste with a ratio of 30% and 70% in producing this solid waste, and also other researchers such as [43] [44] [45] for TKKS converted into bio hydrogen, and biogas [27] [46] [47] and bioethanol [48].Source: [32] The liquid waste generated in the form of water and sludge comes from the sterilization station, sludge tank, sludge separator tank, oil purifer, and hydrocyclone.Each station produces different liquid waste, the composition of solids and water is different.For liquid waste containing water produced from sterilization stations, and hydrocyclone while sludge is produced from sludge tank stations, sludge separator tanks, and oil purifiers.The composition of the amount containing water is 28,337.73kg hour -1 , and the composition of sludge is 13,340.097kg hour -1 .The total amount of liquid waste generated is 69.46% (41,677.83kg hour -1 ).The potential development of liquid waste can be used as another potential source of energy [17] [7] and biohydrogen [49] [32] [50] and water [51].Source: [32] The liquid waste generated in the form of water and sludge comes from the sterilization station, sludge tank, sludge separator tank, oil purifer, and hydrocyclone.Each station produces different liquid waste, the composition of solids and water is different.For liquid waste containing water produced from sterilization stations, and hydrocyclone while sludge is produced from sludge tank stations, sludge separator tanks, and oil purifiers.The composition of the amount containing water is 11,065.63kg hour -1 , and the composition of sludge is 5,948 kg hour -1 .The total amount of liquid waste generated is 65.81% (16,814.23 kg hour -1 ).The potential development of liquid waste can be used as another potential source of energy [17] [7] and biohydrogen [49] [32] [50] and water [51].Source: [32] The process of wastewater potential can provide electricity potential for the value converted to wastewater.This process is carried out through the technique of utilizing liquid waste in POME ponds, eventually processed through methane capture into electrical energy [18].The development of biogas electricity has long been recognized in the industrial world, processed through a series to produce renewable energy for the benefit of the industrial world and / or in government circles, industrial users and stakeholders [52].The total capacity of liquid waste produced by the process of each station produces water and solids amounting to 28,337 kg hours -1 (67.99%).According to others [49] [53] the potential development of liquid waste can be used as a potential electricity (Kwh), heat energy source (MJ).

Conclusions
The process of using inputs to produce outputs in the mass balance process for land clearing, tillage and planting in plantation areas has an impact on the use of inputs in the field of oil palm plantations on the environment.The use of fertilizers, organic and inorganic, also has a positive influence on the creation of potential emissions resulting from the use of land preparation of 262 kg cycle -1 ; tillage 236 kg cycle - 1 and planting 165 kg cycle -1 .The largest potential emission value was generated during the land preparation period because more diesel and gasoline were used to clear the land.Electrical waste energy (E) generated until 2050 for total electrical energy generated amounted to 7,343,834.558GW.The energy potential increases from 2016-2032 by 7,343,805.845GW, and the electricity potential in 2033 remains (stagnant) from year 17 (2033-2050).For the electrical energy required by the factory process (Ep) against 20% efficiency of the power plant is 1,468,766.912GW, while the electrical energy generation from waste (P) is 167.667GW.

17 =
Conversion value from m3 unit to Nm unit 3 LHv = Low heating value of methane (= 35.8 MJ Nm -3 ) 0.35 = Conversion efficiency from biogas to electricity

8 Figure 1 .
Figure 1.Balance sheet of 30 tons per hour FFB processing -1 at the mill

Figure 2 .
Figure 2. Balance sheet of 60 tons per hour FFB processing -1 at the mill

Table 1 .
Potential Solid Waste in the 30 ton hour palm oil process-1

Table 2 .
Potential Solid Waste in the 60 ton hour palm oil process-1