COMPARISONAL ANALYSIS OF FLY ASH (CASE STUDY AT PLTU PORT RATU)

Fly ash can include toxins from high levels of bottom ash in some circumstances, such as burning of solid waste to generate power (resource recovery facilities or waste-to-energy conversion), and combining fly ash and bottom ash together delivers corresponding quantities of contaminants. Under some conditions, fly ash can be classified as non-hazardous waste, but if it is not blended, it can be classified as hazardous waste. The goal of this research was to find out about the differences between fly and bottom ash, as well as the influence of fly ash on bottom ash in terms of avoiding abrasion. In addition, the study's goal was to see how fly ash affected coconut fiber's resistance to abrasion. This study employed a quantitative technique in which the researcher used primary data sources such as questionnaires and observations, as well as secondary data sources such as prior studies. The findings revealed that fly ash had no effect on bottom ash in terms of avoiding abrasion. Furthermore, it is well known that neither fly ash nor bottom ash are effective against coconut fiber. Fly ash has a coarser texture than bottom ash, according to the findings. The regression test revealed that there was no difference between fly ash and bottom ash, as well as coconut coir, in terms of reducing abrasion.


Introduction
Indonesia is the largest archipelagic country in the world which has approximately 17,508 islands connected by straits and seas, and has a coastline of 81,000 [1] . Approximately 75% of cities in Indonesia are located on the coast with a population of more than 100 million people. This causes the coastal area to develop rapidly to meet various human needs including; residential areas, ports, industrial areas, fisheries, agriculture, and tourist areas. This indicates that the coast and the ocean have an important role for life. As a result, coastal areas in Indonesia experience many problems such as erosion, abrasion, sedimentation, and saltwater intrusion [2]. The beach is a complex environment that is influenced by the intensity of marine processes, fluvials and their movements. The type of beach as a reflection of the mechanism of the erosion process, land origin acceleration, and washing. In this case, the authors approach the characteristics of the coast and the wave flux method based on the prediction of wind speed data [3].
The southern coast of Java is a coastal area that is directly adjacent to the open sea, namely the Indian Ocean, this boundary directly forms the characteristics of the oceanographic parameters that occur in the southern coast of Java, in addition to oceanographic parameters, the southern sea also forms a unique geology that forms different oceanographic conditions compared to other seas [4].The southern coast experiences more abrasion and has the characteristics of deeper waters because it borders the Indonesian Ocean which has larger currents and waves than the Java Sea(Pradipta, 2016) [5].
The coastal area is a transitional area between sea and land. This condition causes coastal areas to be under pressure from various activities and phenomena that occur on land and at sea. Phenomena that occur on land such as flood erosion and activities carried out such as residential development, clearing of forests for rice fields, pond construction and so on ultimately have an impact on coastal ecosystems. Similarly, phenomena in the ocean such as tides, storm waves and so on [6].
Abrasion is an event of retreat of the coastline in coastal areas that are vulnerable to activities that occur on land and at sea [7]. Activities such as logging of mangrove forests, sand mining, as well as the phenomenon of high waves, and sea tides have the impact of abrasion or coastal erosion [8]. Erosion that occurs on the mainland of the coastal area causes sediment transport to move from its place of origin and along the direction of the incoming wave, thereby affecting changes in the coastline. Abrasion is a problem for ecosystems and settlements in coastal areas. The impact of abrasion is the decline of the coastline which can threaten the buildings and ecosystems behind the coastline [9]. Mitigation efforts need to be carried out to avoid casualties, as well as the impact of potential disasters, so that steps and preparedness are obtained before a disaster occurs. In overcoming abrasion, fly ash and bottom ash are generally applied. As is known, fly ash is used more often because it is said to be more effective than bottom ash. Abrasion resistance can occur when the material used also has a high pressure [10].
Fly ash is a residue or waste from the coal combustion process which is currently being used as a partial replacement for cement or as a substitute for fine aggregate in the manufacture of concrete [11]. While bottom ash is a type of ash used to process a combustion used in PLTU. Bottom ash is basically better known for its larger size than fly ash. Bottom ash is said to be more reliable to make the pozzolanic reaction ineffective while fly ash is more effective. In addition, the use of bottom ash provides lower pressure and abrasion resistance when compared to fly ash.
In addition, fly ash can also be used to increase the durability of concrete, one of which is resistance to sulfate [12]. Fly ash is a by-product (waste) from industry which has a fairly high silica (Si) content. Silica (Si) and Calcium (CaO) are one of the main ingredients needed to produce portland cement. Fly ash is categorized as a hazardous material, so if it is to be used as a material, it must be processed first so that the content of harmful substances in fly ash can be controlled (PP. No. 101, 2014). Control of hazardous substances in fly ash can be done by geopolymerization. Fly ash is a residue from the combustion of coal in power plants. Fly ash has a melting point of about 1300 °C and has a density between 2.0 -2.5 g/cm 3 [13].
In addition, many infrastructure developments can also utilize fly ash as a basic material or mixture for road construction and various other uses [14]. The effort to utilize fly ash is in accordance with the implementation of priority programs on the Making Indonesia 4.0 road map that has been launched by the government. Fly ash from coal combustion at PLTU Palabuhanratu which is currently planned as the main material for the abrasion-resistant embankment will later be used for internal and external civil purposes at PLTU Palabuhanratu. On the other hand, PLTU Palabuhanratu, which is located in Sukabumi Regency, West Java, as one of the largest sources of fly ash in Indonesia, is located near the coast, thus creating an opportunity to be able to utilize fly ash from PLTU Palabuhanratu in the construction of seaside buildings, one of which is the Embankment. Therefore, this study was conducted to find the right method in utilizing fly ash from the Palabuhanratu PLTU in the manufacture of embankments to prevent abrasion. Make maximum use of fly ash and reduce the use of cement as much as possible.
Fly ash is solid waste resulting from the combustion process in the furnace at the PLTU which is then carried out by the remnants of combustion and captured using an electrostatic precipitator [15]. Fly ash consists of inorganic materials contained in coal that have undergone fusion during combustion. This material solidifies while in the exhaust gases and is collected using an electrostatic precipitator. Because these particles solidify while suspended in the exhaust gases, fly ash particles are generally spherical in shape. The fly ash particles collected in the electrostatic precipitator are usually silt (0.074 -0.005 mm) in size. This material is mainly composed of silicon dioxide (SiO2), aluminum oxide (Al2O3) and iron oxide (Fe2O3).
Fly ash is a material produced from the coal combustion process in power generators, so all of its properties are also determined by the composition and properties of impurity minerals in coal and the combustion process [16]. In this coal combustion process, the melting point of coal ash is higher than its combustion temperature. And this condition produces ash which has a very fine grain texture. Coal fly ISSN 2620-9632 Vol. 3., No. 2, Nov 2020, pp. 54-66 ash consists of fine grains which are generally solid or hollow spheres. The particle size of fly ash resulting from burning bituminous coal is smaller than 0.075mm [17]. The density of fly ash ranges from 2100 to 3000 kg/m3 and the specific area (measured according to the Blaine air permeability method) ranges from 170 to 1000 m2/kg). [18] Based on the research background and the formulation of research problems that have been discussed and put forward by the author above, then the purpose of this study is (1) to determine the characteristics between fly ash and bottom ash through the comparison method), (2) determine the effect of fly ash on bottom ash in preventing abrasion and (3) determine the effect of fly ash on coconut fiber in preventing abrasion.

Method
In making research successful, it is necessary to determine a method used in research. In carrying out this research, the researcher uses a quantitative method which is a method in which the researcher uses a survey to obtain data that can produce statistical values [19]. In this study, researchers used multiple regression analysis techniques where the X1 variable is Fly Ash and X2 is Bottom ash while the Y variable used in this study is Decrease).
The research "Comparative analysis of fly ash (case study at PLTU Pelabuhanratu)" includes several stages. The stages of research carried out include.
 Literature study and data collection. Preparation in the form of a literature study using various previous research results as a reference without reducing creativity and freedom in conducting research tests.
 Analyze the need for tools and materials, analyze and provide the tools and materials needed in research.
 Analysis of the effectiveness of the materials used.
 Analyze the results, analyze the survey results and identify the results of the analysis. In this study, data collection was carried out using two types of data, namely primary and secondary. Primary data collection is done using observation, while secondary sources use literature studies. This research was conducted at PT. Indonesia Power PLTU Pelabuhan Ratu on " Fig.2

Results and Discussion
In Table.1. are the results of the analysis of the characteristics of fly ash and bottom ash in PLTU Pelabuhan Ratu: The table above is the composition of fly ash and bottom ash. If the two ingredients are mixed with other ingredients, then of course the percentage will be reduced. This is because there has been a mixing process with other ingredients.  In " Table.2" it can be seen that the use of Fly ash is better than bottom ash. This can be seen from the design value of coal and worst coal which has a higher number compared to bottom ash in "table 2". Fly ash is better known as a mixture of fine coal while bottom ash is mixed with sand and shards in the ocean area. This causes the quality of bottom ash to decrease. Large volume levels present a problem where it is necessary to provide a place for stockpiling to occur [20].
According to Farhan & Nugraha (2021), fly ash and bottom ash have different textures when the control process occurs [21]. In fly ash, there is a crack that makes the texture a little harder. Whereas in bottom ash there are no shards, even the texture is smoother. The granules in fly ash have a greater density than bottom ash. This makes bottom ash slower to occur. So it can be concluded that the smoother the texture used, the more difficult the material can be weathered.
According to Gan et al., (2018) the gradation of bottom ash can only reach the highest percentage, which is 80 percent, so that the density of bottom ash combined with other materials decreases. In his research, rock ash was used as a mixture material [22].
The following is a comparison of the weight of the oxide composition in fly ash and bottom ash in " Table 3" The table above is a comparison of the weights of fly ash and bottom ash. The highest yield was obtained by SiO2 with a percentage of more than 30 percent. However, P2O5 does not get a percentage yield on bottom ash. So based on " Table 3" it can be seen that the use of fly ash is superior to bottom ash.
The test was carried out in the composition of 100% fly ash, which can be seen in " Table 4"  decreasing  every week.
ISSN 2620-9632 Vol. 3., No. 2, Nov 2020, pp. 54-66 Week 1 Week 2 Week 3 Week 4 Week 5 Week 6 Week 7 Week The table above is the shrinkage data that occurs by combining 100 fly ash in the first sack. The following is " Table 5" with the percentage of each composition The table above is data that was processed by researchers through SPSS to show evidence of the effect of variables X1, X2 on Y. The percentage of fly ash used for this study started from 5 percent to 95 percent. Each percentage of fly ash uses a similar weight of 44.5 kg.
In " Table 6" is data that has been processed through SPSS)  Based on " Table 6", it can be seen that the t value obtained is 5.125 where the result is greater than the alpha value of 0.05. So based on this, it can be concluded that there is no significant effect between fly ash and bottom ash in preventing abrasion. The following is a linear regression equation that can be formulated in this study.

Y= 5.215+0,049X2
Through the value of the constant or variable for the decrease in fly ash, namely 5.215, it can be concluded that, X2, namely bottom ash which is added by 0.049, will decrease by 5.215. So it can be concluded that the decrease that occurs is 52 percent when fly ash and bottom ash are used simultaneously.
These results are in line with research conducted by A Rivai et al., (2020) where it is said that the use of fly ash has decreased for seven days [13].
The following is " Table 7" comparison of bottom ash with coconut fiber: Based on " Table 7" above, it can be seen that the calorific value of bottom ash is 3255 kcal/kg, this value indicates the potential of bottom ash to be used in the textile industry. Based on this, it can be concluded that bottom ash can be used to be mixed in making briquettes.
The following " Figure 3" shows a graph of biobriquettes:

Fig. 3. Biokriket Chart
Through the results of the tests carried out, it appears that bottom ash cannot make briquettes form optimally. However, it actually makes the briquettes to be destroyed. As is known, coconut fiber has a less strong texture so that when the two are put together it will provide better strength in pressure [23]. According to Bayuaji et al., (2015), coir mixing between fly ash and coconut coir can give stronger results in cement formation [24]. . The following " Table 8" is the composition used by researchers in the manufacture of cement through the use of fly ash and coconut. Based on the results of the research conducted, it can be seen that the use of fly ash is greater than the use of other materials. In this study, cement used 30 percent of the composition of coconut fiber and fly ash. On research, it is known that the amount of coco coir used is 25 percent while the amount of fly ash used is 5 percent. Hawari & Lizar (2021) have conducted a study involving the mixing of fly ash, bottom ash and coconut coir [25]. Based on the results of this study, it is said that the mixture of fly ash and bottom ash has decreased due to the presence of less effective asphalt content. Through the test, it was stated that the VMA value in fly ash obtained an increasing value, as well as bottom ash. This is due to the pozzolanic properties contained in the two types of ash.
Here is " Table 9" with each composition percentage:  Based on the data above, the researchers used fly ash percentages ranging from five percent to 95 percent with a weight of 27.5 Kg. In this case, the researchers made a comparison of fly ash against coconut fiber. The researcher used an increasing weight of fly ash for each percentage and using a decreasing weight of coconut coir for each percentage of fly ash. So, based on " Table 9", it can be seen that the decline occurred steadily starting from 16.45 to 13.05.
In " Table 10" is data that has been processed through SPSS Based on the data that has been processed through the use of SPSS, the researchers obtained the t value for coconut coir amounted to 25,629 which was tested for a decrease in. Therefore, through the t value obtained, where there is a number greater than the alpha value, it is concluded that there is no significant effect between fly ash on the use of coconut fiber in reducing abrasion. So, the regression equation that can be formulated is as follows: Y=12.652+0,152X2 Based on the regression equation, the constant value which is the variable for reducing fly ash gets the number 12,652 with the X2 variable, namely coconut husk, which is 0.152. So it can be concluded that the addition of coconut fiber by 0.152 will experience a decrease in fly ash by 12.652 or by 12 percent.
Based on these tests, it can be said that the results of the study are not in line with the research of Bayuaji et al., (2015) which states that the combination of fly ash and coconut fiber can give results that affect the materials used [24]. However, in the research of Hawari & Lizar (2021), it is said that there is a decrease when fly ash and coconut fiber are used to overcome abrasion [25].

Conclusion
Based on the results of the tests that have been carried out, it can be concluded that the use of fly ash in the prevention of Abrasion does not have a significant effect, as well as when combined with the use of coconut fiber. In this case, the usage will decrease. As is well known , the character of fly ash is harder due to the presence of cracks, while bottom ash has a very fine texture(As is known, the character of fly ash is harder due to the presence of cracks, while bottom ash has a very fine texture. By Therefore, it can be concluded that the use of a harder texture will be better because there will be a decrease (Therefore, it can be concluded that the use of a harder texture will be better because there will be a decrease. Therefore, it can be concluded that the use of a harder texture will be better because there will be a decrease.. In this case, it is necessary to understand that the softer and more liquid the ash is used, the less effective it will be (In this case, there needs to be an understanding that the softer and more liquid the ash used, the less effective it will be. Through multiple regression testing, it was found that the addition of bottom ash of 0.049 can give a decrease in fly ash of 5.215 (Through multiple regression testing, it was found that the addition of bottom ash of 0.049 can provide a decrease in fly ash of 5.215. Meanwhile, the use of coconut husk which is added by 0.152 will decrease fly ash by 12.652(Meanwhile, the use of coconut husk which is added by 0.152 will give a decrease in fly ash by 12,652.