The potential utilization of solid waste as alternative fuel in cement industry (case study of PT Semen Padang)

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Introduction
The demand for cement in many countries has increased rapidly along with the continued development of the construction industry, a result of increased infrastructure development and urbanization.Cement is one of the most widely used and produced materials in construction globally.This increase in cement demand occurred quite significantly between 2010 and 2014 from 3,208 Mton to 4,290 Mton, and has been relatively stable since 2019 at 4,100 Mton.Cement production has many environmental impacts, ranging from high Greenhouse Gas (GHG) emissions to high resource use and energy consumption, namely fossil fuels and electricity.The cement industry is estimated to be the cause of about 5% of total CO2 emissions [1] and accounts for 12-15% of global industrial energy use [2].
Coal is the main energy source for the cement industry, so the scarcity of coal has a close relationship with the cement industry.Today many cement industries are trying to reduce dependence on coal and switch to alternative energy sources that are more environmentally friendly such as renewable energy.According to the International Energy Agency (2021), global coal production has decreased in line with the increase in the use of renewable energy and efforts to reduce greenhouse gas emissions [3].This makes the cement industry have to find alternative new energy sources to meet their energy needs.Some cement industries have also begun to consider the use of Alternative Fuels (AF) such as biomass, gas, and electricity to produce cement.
 Corresponding author : yenniyasril@gmail.comPT Semen Padang is the oldest company that produces cement and other products since March 18, 1910.In the cement production process, PT Semen Padang uses coal as the main fuel.However, since 2015 PT Semen Padang has optimized the use of waste as AF.This work program is implemented by PT Semen Padang under the Alternative Fuel and Raw Material (AFR) Unit of the Production Support Department.The AFR unit has a function to subsidize the main fuel with the aim of saving resources and using environmentally friendly energy.Currently, PT Semen Padang has utilized two types of solid waste, namely rice husks and Spent Bleaching Earth (SBE) [4].
In 2023 -2030, PT Semen Padang's AFR unit targets to start utilizing several types of solid waste deposited by solid waste producing companies in Sumatra.The types of solid waste to be processed include SBE, rice husks, calliandra, sawdust, and palm fruit fiber.To achieve this target, this study aims to analyze the potential utilization of solid waste into AF at PT Semen Padang.

Methodology
The solid waste used as AF at PT Semen Padang in this study is SBE, rice husks, calliandra, sawdust, and palm fiber.Before being utilized into AF, each solid waste must be tested so that it meets certain parameters.Tests were carried out on the parameters of calorific value and proximate analysis (moisture content, ash content, volatile content, and fixed carbon).[5] The test results are compared with the applicable regulations, namely the Ministry of Industry Regulation in 2017 concerning Guidelines for Technical Specifications of Refuse Derived Fuel (RDF) as an Alternative Fuel in the Cement Industry.After obtaining the test value of each solid waste, then calculated the total mass of each solid waste, which is projected based on solid waste production from the depositing company.
The potential utilization of solid waste is measured based on the calculation of Thermal Substitution Rate (TSR).TSR calculation is one of the Key Performance Indicators (KPI) in the assessment of Green Industry and PROPER.Green Industry and PROPER assessments are important for cement companies because they improve sustainability, legal compliance, reputation, and innovation, while supporting global goals of sustainability and business growth.Furthermore, the need for tools to support the use of solid waste as AF was analyzed.[6]

Research tools and materials
The tools needed in this study are bomb calorimeter for calorific value testing, moisture analyser for moisture content testing, furnace for ash content and volatile content testing, and analytical balance for weighing test samples.The materials needed are 8 grams of samples from each solid waste, namely SBE, rice husks, calliandra, sawdust, and palm fiber.Prior to testing, samples are prepared to ISO/IEC 27001 standards.Sample preparation is done by cutting the sample into small sizes of ±5 mm, drying in the sun, and putting the sample in clear plastic with the name, date of collection, and location of sampling.

Analysis of solid waste characteristics
Analysis of solid waste characteristics is carried out by laboratory analysis including calorific value testing and proximate analysis of each solid waste.Testing is carried out duplo.
Calorific value testing was performed using ASTM D 2015: Standard Test Method for Gross Calorific Value of Solid Fuel by the Adiabatic Bomb Calorimeter [7].The test steps include weighing the sample by 1 gram and placing it in an iron dish, attaching the cup with the sample to the calorimeter bomb circuit, inserting the calorimeter bomb circuit into a calorimeter bomb vessel that has been filled with 130 atm pressure gas, filling the calorimeter bomb bucket with 2 liters of water, starting the engine and checking the initial temperature, pressing the combustion button for 7 minutes, Turn off the engine and see the calorific value and final temperature of combustion on the calorimeter bomb screen.The test was carried out 2 times.
Proximate analysis testing includes measurements of moisture content, volatile content, ash content and fixed carbon.Moisture content testing was performed using the ASTM 3173-17 Moisture in the Analysis Sample of Coal and Coke method [7].The step of testing the moisture content is to prepare a sample of 5 g into the dish moisture balance.The tool is reviewed and automatically the analysis results will be listed on the screen Ash content testing was performed using ASTM 3174-12 Ash in the Analysis Sample of Coal and Coke from Coal method [7].The test steps include weighing porcelain dishes, inserting a sample of 1 gram, heating in a furnace at 500 °C to 815 C ± 10 °C for 30 -60 minutes and holding at 815 °C for 60 minutes, cooling in a desiccator for 15 minutes, and calculating the ash content using the equation 1.
%AC = (m3 -m1)/(m2 -m1)×100% (1) where: where: %FC = fixed carbon content (%) %IM = inherent moisture (moisture content) (%) %AC = ash content (ash content) (%) %VM = volatile matter (volatile content) (%) The results of the characteristic data of each solid waste are then compared with the AF quality standard to find out whether the solid waste to be utilized meets the applicable AF quality standard standards.The AF quality standard used is the Technical Specification Guidelines for Refuse Derived Fuel (RDF) as an Alternative Fuel in the Cement Industry issued by the Ministry of Industry in 2017, as seen in

Projected total mass of solid waste
The projection of the total mass of solid waste aims to provide an idea of the amount of solid waste that will be available in the period 2023-2030.PT Semen Padang assumes that every 3 years there will be an addition of 5% of the total solid waste in 2023 (PT Semen Padang, 2022).This assumption is based on industrial growth and the potential increase in solid waste production along with the development of related sectors.By taking into account this addition, it is expected to obtain a more realistic projection of the total mass of solid waste that can be utilized as AF by PT Semen Padang.
The projection of the total mass of solid waste that will be utilized as AF in 2023-2030 can be done with the following steps.
a. Collecting existing data on the total mass of solid waste of PT Semen Padang in the previous period; b.Assumes an increase in solid waste mass by 5% every 3 years; c.Calculates the projected total mass of solid waste for 2023-2030, with the equation 4.
Information: mn = Solid Waste Mass Projections (tons) m0 = Mass Existing waste (ton) r = increase in mass of solid waste (%) n = Term (years)

Thermal Substitution Rate (TSR) calculation
TSR is a parameter used to measure the percentage of replacement of main fuel with AF in a production process.TSR indicates how much percentage of the main fuel that can be replaced by AF in providing energy for the process.The calculation of TSR is done by comparing the energy produced from AF with the energy produced from the main fuel.
In the Decree of the Minister of Industry Number 512/M-IND/Kep/12/2015 concerning the Establishment of Green Industry Standards for the Portland Cement Industry, one of the technical requirements that must be met by the cement industry as a green industry is TSR or thermal substitution level.To meet the Green Industry Standard, the cement industry performs TSR calculations by considering the use of biomass or non-biomass alternative fuels.In the decree, a minimum TSR limit of 1% thermal energy per plant site was set [7].
In addition, PT Semen Padang also has an internal TSR target that must be achieved.This TSR target reflects the company's goal of increasing the use of AF and reducing dependence on fossil fuels.By comparing TSR calculations with regulatory requirements and internal company targets, it can be evaluated to what extent the cement industry has achieved the expected level of performance in the use of AF.
Based on Waste and Supplementary Cementitious Materials in Concrete, TSR can be calculated by the following steps.[9] a. Calculation of the total calories of each solid waste.

Tool requirements planning
The steps in planning tool requirements are as follows: a. Identify the types of solid waste that require the use of each treatment tool.b.Calculate the mass of solid waste to be treated for each tool.c.Determine the operational time of the tool in hours per year.d.Calculating the number of tools needed can be calculated using Equation 8. ntools = mwaste/(Ctool × t) (8) where: n tools = Number of tools (units) m waste = Mass waste (ton/year) C tools = Tool Capacity (ton/hour) t = Operating Time (hours/year)

Analysis of solid waste characteristics as AF
The results of testing the characteristics of solid waste to be used as AF can be seen in Table 2. Tests were carried out on calorific values and proximate analysis.Calorific value testing is carried out to evaluate the calorific value of solid waste that will be used as AF in the cement manufacturing process.The calorific value of solid waste indicates the amount of energy that can be produced when the waste is burned.This calorific value testing is important in determining the energy contribution that solid waste can make in place of primary fuels, such as coal.solid as an effective and efficient source of energy.[10].The same is true for rice husk waste which in this study has a calorific value of 3,239 Mcal/ton, while Noviyarsi's research (2015) produces a calorific value of rice husks of 3,300 kcal/kg [11].Mulyasari (2013) research states the calorific value of branch calliandra and stem calliandra wood is 3,931 kcal/kg and 4,059 kcal/kg respectively [12].This value is not much different from the results of measuring the calorific value of calliandra waste in this study of 4,185 Mcal/ton.However, for palm fiber waste, different results were obtained from other studies.In this study, the calorific value of palm fiber waste was 3,109 Mcal/ton.Research by Subagyo (2012) states that the calorific value of palm fiber is 4,502.983kcal/kg [13].This difference in results is due to differences in test methods and material characteristics.Nevertheless, these results reflect that palm fiber still has promising potential in contributing calorific value as AF.
Sawdust waste in this study showed a calorific value of 4,088 Mcal/ton.Malakauseya's research (2013) resulted in the calorific value of sawdust is 4,475.53kcal/kg [14].Overall, the results of this study provide important information about the calorific value of solid waste that can be used as alternative fuels.Based on Samsinar research (2020), it is found that the calorific value of a material is influenced by several factors including the characteristics of the material, the temperature around combustion, the density value, and the measurement method used [15].According to research by Nabawiyah and Abtokhi (2010), the greater the type of heat produced by the material, the higher the value of heat capacity and the calorific value contained in it [16].This suggests that materials with high calorific value have greater energy potential.Increased compressive strength and density of materials can also increase the calorific value.
The Inherent Moisture of solid waste indicates the percentage of Inherent Moisture relative to the total mass of that solid waste.Moisture testing is important in evaluating the potential of solid waste as AF, as high Inherent Moisture can reduce calorific value and affect combustion efficiency.
SBE waste in this study has a Inherent Moisture of 3.80%.This value is lower than Robiansyah's Research (2022) which states that SBE Inherent Moisture ranges from 4.16-30.83%[10].This is influenced by differences in sampling time and the influence of weather factors.Rice husk waste in this study showed a Inherent Moisture of 13.62%.This value is higher than Noviyarsi's (2015) research which ranged from 6.65% -7.01%[11].This difference can be caused by differences in sampling dates, where environmental conditions at the time of collection differ.
Calliandra waste in this study showed an average inherent moisture of 16.39%.Mulyasari research (2013) reported that the moisture content of branch calliandra wood is 12.08% and stem calliandra wood is 11.53% [12].The results of this study showed that calliandra waste in this study had a relatively higher inherent moisture.The inherent moisture of palm fiber waste in this study was 36.82%.This value is much higher than Subagyo's (2012) research which found the moisture content of palm fiber was 11.17% [13].
The same is also found for the moisture content of sawdust waste.In this study, the inherent moisture of sawdust waste was 15.44%.This value is higher than Malakauseya's (2013) research with a sawdust moisture content of 10.48% [14].Based on Junary's (2015) research, Inherent moisture has an inverse influence on calorific value [17].That is, a decrease in moisture content in the material leads to an increase in calorific value.
The ash content of solid waste indicates the percentage of ash content relative to the total mass of solid waste.Ash content testing is important in evaluating the potential of solid waste as AF, as high ash content can affect combustion efficiency and produce residues that can disrupt the production process.
Solid waste that has the highest ash content is SBE, which is 60.68%.This result is in line with Yusnimar's (2012) research which obtained SBE ash content of around 62.19% [18].According to research by Saputri and Riyandini (2020), the relatively high ash content in SBE occurs due to soil particles, bleach residues, and other minerals left behind in waste after the oil bleaching process [19].This high ash content reflects the content of minerals and other inorganic components derived from vegetable oil raw materials.Therefore, although the Inherent moisture is relatively low, the ash content remains high due to the mineral content contained in SBE.
The solid waste that has the lowest ash content is sawdust at 0.75%.Setiyadi's research (2018) recorded variations in sawdust ash content between 1.34% to 4.90% [20].The results of this study tend to have lower ash content.Solid waste with low ash content tends to be of better quality as an alternative fuel.According to Azzani's research (2019), low ash content indicates that the waste has a higher organic matter content, so that the waste has the potential for higher calorific value and better combustion efficiency [21].However, other factors such as waste composition and other technical requirements also need to be considered in evaluating waste quality as an alternative fuel.
Meanwhile, rice husk waste has an ash content value of 35.79%.This value is higher compared to the results of other studies.These differences are influenced by differences in sources or measurement methods.Then followed by palm fiber and calliandra waste, with ash content of 2.24% and 1.35% respectively.Haq's research (2018) produced an ash content of palm fiber of around 1.32%, which is lower than the results of other studies [22].
Volatile solid content waste refers to the percentage of volatile substance content relative to the total mass of solid waste.Testing the volatile content of solid waste is important in evaluating the potential utilization of solid waste as AF, because high volatile substances can affect combustion characteristics and energy efficiency.
Rice husk waste has the highest volatile content with a value of 61.17%.This value is higher than Siahaan's (2013) research which obtained volatile rice husk levels of 20.5% [23].This shows that rice husks have great potential as an alternative fuelsource rich in volatile components.
Meanwhile, sawdust solid waste has the lowest volatile content at 12.21%.This value is almost the same as the results of Anam's research (2019) with a volatile content of sawdust of 12.30% [24].Palm fiber solid waste has a volatile content of 51.75%, which is lower than the results of Simanjuntak's research (2022) with a range of 40.91-76.10%[25].SBE solid waste has a volatile content of 23.32%, which is close to the range of 15.41-22.71% of Saputri's research results (2020) [19].Calliandra solid waste has a volatile content of 22.56%, which is also in accordance with the results of Yanti's research (2023) with Volatile Matters in the range of 20.996-23.967%[26].
Fixed carbon content of solid waste refers to the percentage of stable and non-combustible carbon content relative to the total mass of solid waste.High carbon content can increase the calorific value of solid waste and combustion efficiency.
Sawdust solid waste has the highest fixed carbon content with a value of 71.61%.This is not much different from the results of Anam's research (2019) which obtained a fixed carbon content of sawdust of 66.55% [24].These results suggest that sawdust has significant potential as a carbon source.Meanwhile, rice husk solid waste has the lowest fixed carbon content with a value of 6.58%.This value is far different from the results of Siahaan's research (2013) which produced fixed carbon levels of rice husks of around 41.3% [23].
Calliandra solid waste has a fixed carbon content of 59.71%, which is quite close to the results of Yanti's research (2023) with a value of 64.99-71.086%.Palm fiber solid waste has a fixed carbon content of 9.21%, this value is close to the results of Simanjuntak's research (2022) with a range of 5.59-10.40%[25].SBE solid waste has a fixed carbon content of 12.20%, which is quite significant from the results of Yusnimar's research (2012) with a fixed carbon SBE content value of 31.57%[18].In general, in the context of utilizing waste as an alternative fuel, waste with high levels of fixed carbon tends to be considered to have better quality.High levels of fixed carbon indicate that waste has the potential to produce heat efficiently and provide a higher calorific value.
Furthermore, the results of this characteristic test are compared with the Technical Specification Guidelines for Refuse Derived Fuel (RDF) as an Alternative Fuel in the Cement Industry, to determine the extent to which this solid waste meets the requirements set [8].The results of the comparison between the laboratory test results of each solid waste with applicable regulatory standards can be seen in Table 2. From the results of this comparison, it was found that most solid waste meets the regulatory standards set to be an alternative fuel in the cement industry.However, there are three parameters that have not met the standards, namely for SBE waste that does not meet the parameters of calorific value and ash content, and for palm fiber waste that also does not meet the parameters of moisture content.For the calorific value of solid waste used as AF in the cement industry, it must have a calorific value of > 3000 Kcal/kg.SBE waste only has a calorific value of 2394 Kcal/kg.For ash content parameters, SBE waste also does not meet the standard.The required ash content was < 30%, while in this study an ash content of 60.8% was obtained.For Inherent moisture parameters, waste that has not met is palm fiber waste with a inherent moisture of 36.82%.This value does not meet the standard of moisture content ≤ 20%.
Types of solid waste that meet applicable standards are rice husks, calliandra and sawdust.For SBE and palm fiber, there is still an opportunity to be used as AF by carrying out additional processing.Solutions that can be taken include blending with other fuels that have high calorific value, ensuring optimal drying conditions, [27,28] and briquetting for biomass waste [29].With this approach, solid waste can be treated and utilized efficiently as AF in the cement manufacturing process, so that it can still provide positive economic and environmental benefit [30].

Total mass of existing solid waste
The existing data on the total mass of solid waste is the result of collecting information on the amount of solid waste produced in the previous period.This data is obtained based on data on the waste receipt of the depositing company to PT Semen Padang.This data includes a list of waste disposal companies as well as the total waste generated.Data on the existing total mass of each solid waste can be seen at Table 3 [31].
Based on Table 3, the solid waste that has the largest total mass is SBE at 31,800 tons/year.SBE suppliers come from three companies located in Padang City.Furthermore, calliandra waste has the largest total mass of 30,000 tons/year.PT Semen Padang's CSR collaborates with several District/City Environmental Agencies (DLH) in West Sumatra in cultivating calliandra.PT Semen Padang's CSR supplies calliandra waste with a total mass of 2,500 tons/month.Rice husk and sawdust waste has a relatively smaller total mass of 6000 tons/year and 600 tons/year.

Projected total mass of solid waste
The total mass projection data of solid waste is data on the estimated amount of solid waste which aims to provide a clear picture of the potential use of solid waste as AF in the cement manufacturing process at PT Semen  4 shows the estimated amount of solid waste mass in different stages.There is a progressive increase in the total mass of waste from stage to stage, which is 5%.This data provides important information for PT Semen Padang in planning solid waste management and its utilization as AF in the future term.The projection results also show SBE waste has the largest total mass, reaching 35,060 tons in phase III.

Potential utilization of solid waste as AF
Analysis of the potential utilization of solid waste as AF is carried out by considering aspects of solid waste quality, which is expressed in the Thermal Substitution Rate (TSR).TSR is a parameter that measures the percentage of replacement of the main fuel with AF in production.TSR calculations indicate the extent to which the main fuel can be replaced by AF in providing energy.
The TSR calculation is done by comparing the total energy from AF with the total energy from the main fuel.
In the Decree of the Minister of Industry Number 512/M-IND/Kep/12/2015 concerning the Establishment of Green Industry Standards for the Portland Cement Industry, the cement industry is required to meet the TSR requirement of at least 1% heat energy per factory site.PT Semen Padang also has an internal target for TSR, which reflects efforts to increase fuel utilization and reduce fossil fuels.By comparing TSR calculations with internal regulations and targets, performance evaluation of alternative fuel use can be carried out.
The results of the TSR calculation can be seen in Table 5 and Table 6.The entire total TSR at PT Semen Padang in 2023 -2030 has met the quality standard in the Decree of the Minister of Industry Number 512/M-IND/Kep/12/2015 concerning the Establishment of Green Industry Standards for the Portland Cement Industry, where every year, the total TSR produced is greater than 1% (Ministry of Industry, 2015).Then, based on internal TSR target data from PT Semen Padang, it can be seen that there are years where the total solid waste TSR has reached the set target, while in other years it has not reached the set target.
In 2023 to 2025, the total solid waste TSR reaches 5.516%, which significantly exceeds PT Semen Padang's TSR target in the period.In 2026-2027, the total TSR has also met the target with a value of 5.792%.This shows that the use of solid waste as AF has made a positive contribution in the replacement of the main fuel.However, from 2028 to 2030, although the total TSR of solid waste is still increasing, the percentage has not reached PT Semen Padang's higher TSR target.
In dealing with this situation, PT Semen Padang needs to conduct further analysis to evaluate and identify the right solution.One solution that can be considered is to increase the tonnage of solid waste used as AF.By increasing the amount of solid waste utilized, it is expected that the total solid waste TSR can reach or even exceed PT Semen Padang's TSR target in the following years.
In addition, PT Semen Padang also needs to consider the possibility of using other types of solid waste as AF.By expanding the variety of waste utilized, the company can optimize the use of solid waste to achieve PT Semen Padang's higher TSR target. .

Tool requirements planning
In utilizing AF at PT Semen Padang, there are several tools needed to run the process of processing solid waste into AF efficiently.Some of the important tools and facilities that can be identified are: 1. Shredder Shredder is a tool used to chop solid waste into smaller sizes, making it easier to process and mix with other materials [32].

Dryer
Dryer is a tool that serves to dry solid waste.In the utilization of solid waste as AF, the process of drying solid waste is very important to reduce the Inherent Moisture contained in it.Low moisture content helps improve fuel quality and combustion efficiency [28].

Mixing machine
Mixing machines are used to mix two or more types of AF with the aim of achieving a calorific value in accordance with regulatory standards of ≥ 4,000 kcal/kg.By combining AF that has different characteristics, the resulting calorific value can be increased so that it meets the requirements set [27].

Pyrolysis reactor
Pyrolysis reactor is a device used in the pyrolysis process, which is a thermal process in which a material is heated to a high temperature in the absence of oxygen.This pyrolysis process converts organic matter into various components such as gas, bio-oil, and charcoal.Based on Nasrun's research (2016), Pyrolysis reactor can help reduce ash content in alternative fuels through several mechanisms, namely [33] : a) Phase separation During the pyrolysis process, the alternative fuel decomposes into various components, including gas, bio-oil, and charcoal.The ash formed is generally in the solid phase as part of charcoal.
In Pyrolysis reactors, charcoal can be separated from the gas and bio-oil phases, thereby reducing the ash content in the final product.b) Ash reduction Pyrolysis process can reduce ash content in alternative fuels because most of the ash is present in organic matter that decomposes into gas and bio-oil.By removing most of the ashcontaining organic matter, Pyrolysis reactors can produce products with lower ash content.c) Ash material removal Pyrolysis reactors can also be equipped with more advanced ash separation systems, such as filters or separators, to remove finer ash particles from the final product.This helps improve the quality of alternative fuels by reducing the remaining ash content.Furthermore, the calculation of tool needs can be done by following these steps.1. Identify the types of solid waste that require the use of each treatment tool, namely: a) Shredder : Calliandra b) Dryer : palm fiber c) Mixing machine : SBE and Calliandra d) Pyrolysis reactor : SBE 2. Determine the mass of waste to be treated for each tool.Waste mass data can be seen in Table 7. Determine the equipment uptime per year by estimating the number of operating hours per day and operating days per year.Assuming the equipment operating hours at PT Semen Padang are 20 hours/day, while the equipment operating days per year are every day (PT Semen Padang, 2022), the equipment operational time per year is 7,300 hours/year 3. Reduce tool needs by considering tool capacity, waste mass, and equipment operational time per year.Table 8 shows the calculation of the number of equipment needs needed at each stage in the utilization of solid waste as AF at PT Semen Padang.There are 4 types of tools used, namely shredder, dryer, mixing machineand Pyrolysis reactor.Based on the calculations that have been done, the number of tool needs is consistent for each stage.Shredder, mixing machine, and pyrolysis reactor 2 units are needed each, while mixing machine A total of 3 units are required.With this calculation, it is hoped that PT Semen Padang can ensure the availability of adequate tools to run the process of utilizing solid waste as AF efficiently and sustainably.

Conclusions
Based on the research that has been done, it can be concluded that: 1.The projection of the use of solid waste as AF by PT Semen Padang is divided into 3 stages of the design period, namely phase I (2023-2025), phase II (2026-2027), and phase III (2028-2030).The projection data is obtained by projecting data on the total mass receipt of existing waste in the previous period and is assumed to increase by 5% every 3 years.
Padang in the 2023-2030 time frame.The projection of the total mass of solid waste at PT Semen Padang is divided into 3 stages of the design period, namely: 1projected total mass of solid waste for 2023 -2030 in Table
The measurement results show that calliandra type waste has the highest calorific value of 4,185 Mcal/ton, followed by sawdust 4,088 Mcal/ton.Rice husks also show a fairly high calorific value of 3,239 Mcal/ton and palm fiber of 3,109 Mcal/ton.SBE has the lowest calorific value of 2,394 Mcal/ton.The results of measuring the calorific value of this study are almost the same as other studies.SBE waste in this study has a calorific value of 2,394 Mcal/ton.This value is close to the results of Robiansyah's research (2022) with the calorific value of SBE ranging from 2,400 -2,600 kcal/kg

Table 2 .
Comparison of solid waste characteristic test with applicable standards.
*Does not meet applicable regulatory standards

Table 3 .
Existing data on total mass of solid waste.

Table 4 .
Projected total mass of solid waste.

Table 5 .
The result of calculating the TSR value of solid waste.

Table 6 .
The Value of solid waste TSR as AF in 2023 -2030.

Table 7 .
The result of the calculation of fixed carbon solid waste.

Table 8 .
The calculating result of the number of tool needs.
The largest solid waste mass is SBE with a waste mass of 35,060 tons/year in phase III and the smallest solid waste mass is sawdust with a waste mass of 397 tons/year in phase III. 2. The results of the comparison of calorific value and proximate analysis of solid waste with the regulations of the Technical Specification Guidelines for Refuse Derived Fuel (RDF) as an Alternative Fuel in the Cement Industry in 2017 show that solid waste of rice husks, calliandra and sawdust has met applicable standards.For solid waste, SBE has not met the parameters of calorific value and ash content, while for palm fiber waste, it has not met the Inherent Moisture.Parameters. 3. Based on the comparison between the total solid waste TSR and PT Semen Padang's TSR target for 2023-2030, the total TSR has met the target in 2023-2027, with a value of 5.792%.However, in 2028-2030, the total TSR has not met the target set by PT Semen Padang.4. The tools needed to support the utilization of AF for each stage consist of 2 shredder units with a capacity of 2 tons/hour, 2 dryer units with a capacity of 2 tons/hour, 3 mixing machine units with a capacity of 3 tons/hour and 2 pyrolysis reactor units with a capacity of 5 tons/hour.