Energy and Exergy Analysis of Steam Power Plant 3rd Unit PT PLN (PERSERO) Centre Unit Generation Tanjung Jati B Use BFP-T Modification Cycle

Steam power plant Generation of Tanjung Jati B 3rd unit has a capacity of 660 MW. The power plant operational in 2011, because of the long operation process, there will be a decrease in performance. The plant needs to be researched to analyze the performance and losses that occurs in the power plant. Because this also affects the environment if the efficiency of the power plant is high, it can reduce the use of coal. Because coal becomes air pollution and environmental pollution, which can cause acid rain, water pollution, and global warming. This research is used to analyze energy and exergy on the components of a steam power plant. From the results of this research, the largest of destruction exergy boiler is 881.08 MW and the exergetic efficiency is 48.66%. While the rate of the smallest destruction exergy in LPH 3 is 0.6 MW and the exergetic efficiency is 94.45%. The contribution of the largest Losses energy in the boiler is 231 MW and energetic efficiency is 87.05%. While the contribution of the smallest energy Losses in HPH 6 is 0.74 MW and energetic efficiency is 99.23%.


Introduction
Energy is used to support human life, one of them is electrical energy. Given how the vital benefits of electric power, so power plant infrastructure is vital in Indonesia. Therefore, technological advancements also support higher efficiency improvements. One of the electricity producers is the Steam Power Plant (PLTU) which is a thermal power center that is widely used because of its good efficiency to produce electricity that is safe for the environment. The basics that are required for the analysis of thermodynamic system in power plant is including the principles of the law of conservation of mass and conservation of energy, the second law of thermodynamics, and thermodynamic data [1]. We use the second law of thermodynamics to improve the performance of components of a steam power plant [2].
The method of energy analysis and exergy, which gives the conclusion that boilers are the main component of exergy destruction [3]. The entire power plant cycle is divided into three-cycle zones for exergy analysis of coalbased power plants [4]. Hasti et al. Have carried out exergy analysis on ultra-supercritical power plants to find exergy damage in each component of the power plant [5].
Therefore, it can be concluded that the exergy and energy analysis can provide a complete description of the characteristics of the power plant system [6][7][8]. Ganapathy et al. Have determined the energy losses and exergy losses of each component of the power plant [7].
Aljundi [9] showed the performance of a power plant by modeling a steam power plant in Jordan. Naterer et al. [10] Analyzed the coal-fired thermal power plant with measured boiler and turbine losses. Rosen [11] presented energy and exergy-based comparison of coal-fired and nuclear steam power plants. Oktay [12] presented exergy loss and proposed improving methods for a fluidized bed power plant in Turkey.
Based on the description and study of the literature that has been described that the energy and exergy analysis based on the first law and the second law of thermodynamics is used to identify the source of the inefficiency, determine the location and magnitude of the destruction exergy happen so that the power plant being optimal. On this research, analysis energy and exergy at the Steam power plant 3rd Unit PT PLN (Persero) Centre Unit Generation Tanjung Jati B to enhance the optimization of the power plant. This Results of research can be recommended to repair of a component. If the efficiency of a power plant is high, it can reduce the coals. Air pollution, water pollution and global warming much of that demand by coal. If we can reduce coal, the pollution on earth can be reduced.

Research Method
This study used calculations and analysis to obtain the results which are presented in graph plots and table. The

Method of collecting data
This research was conducted by thermodynamic analysis on each component of a steam power plant. This system is simplified by using a volume control system by distinguishing between the inflow and outflow of components. The analysis was carried out to identify the level, type, and location of losses (exergy destruction) caused by incomplete combustion and friction, etc. Constant entropy applies to isentropic processes, so enthalpy when an isentropic state can be calculated by the following equation: (1) The enthalpy data, entropy, and mass flow rate at each point are used to calculate energy and exergy. To facilitate the conduct of research, a flowchart is arranged as shown in Fig. 2.

Equations of Mass Equilibrium
Calculation of the energy in the flow system is open, there are three types of energy transfer the entire control surface: transferring work, heat transfer and energy associated with the transfer of the masses. The first law is applied to the process flow in a steady flow system. In the circumstances of the steady-state, then fluid properties do not depend on time so 0

Energy Calculation Equations in Each Point
In this study carried out by calculating the amount of energy contained in each cycle in Fig. 2 to analyze energy. Multiples of the mass flow rate at a certain point and with the amount of enthalpy at a certain point is the amount of the energy value or formulated in the equation (3) as follows: Energy calculations for coal fuel can be formulated using equation (4) as follows:

Exergy Calculation Equations in Each Point
The exergy calculation equation at each point can be analyzed based on the type of liquid at a certain point.
Open system or control volume is a system in which mass can flow through the limits of the system. An equation of balance exergy control volume equation is as follows: Open system or control volume is a system in which mass can flow through the limits of the system. An equation of balance exergy control volume equation is as follows: (6) Assumptions are used for the analysis of destruction exergy on the system control volume follow as equation (6) So, the equation is as follows [2].
ie ie The equation of energetic efficiency is as follows [2].

Parameters Work Data
Parameters work data is used to exergetic and energetic analysis of the Steam power plant 3rd Unit PT PLN (Persero) Centre Unit Generation Tanjung Jati B is as follows in Table 1.
. The results of analysis coal are as follow in Table 2, value High Heating Value (HHV) is a 24306.98 kJ/kg.  11.82 A specific heat, mass flow, temperature at flue gas and air supply to the boiler is as follow in Table 3. In condenser have cooling water flow to calculate a heat rejected. Specific of cooling water is as follow Table 4.

Results and Discussion
The data used to analyze energy and exergy is from the performance 2017 of Steam power plant 3 rd Unit. The analysis of energy and exergy is as follows:

Energetic and Exergetic Analysis
The energetic analysis is including energetic efficiency and energy losses. The results of exergy efficiency calculations, exergy efficiency, and exergy destruction. The energetic analysis uses data from the performance test in 2017. The results of energetic and exergetic analysis are as follow in Table 5. The exergy efficiency value of HPT, IPT, and LPT has a greater value than the value of energy efficiency, this is because the isentropic value of HPT, IPT, and LPT is greater than the exergy value of the fuel. The exergy efficiency value of BFPT has a greater value than the energy efficiency value, this is because the isentropic value of BFPT is greater than the exergy value of the fuel. The energy efficiency value of HPH 7, HPH 6, HPH 5, LPH 3, LPH 2, and LPH 1 has a greater value than the exergy efficiency value, this is due to the percentage comparison of product exergy and exergy fuel HPH 7, HPH 6, HPH 5, LPH 3, LPH 2, and LPH 1 are greater than the percentage of product energy value and inlet energy. In each components use energetic analysis based of isentropic calculation. Results of energetic analysis with isentropic calculation is as follow in Table 6.

Grassman Diagram
The results of the analysis of energetic and exergetic can be seen in Table 7. The Comparison with a research of Sairam and Kaushik [13] is presented that the boiler has the greatest destruction exergy 1196 MW. The results from Table 7 can be plotted into the Grassman diagram in Figure 3.

Comparison of Energetic Efficiency and Exergetic Efficiency with other Study.
Comparison of energetic efficiency and energetic efficiency with other study is as follows in Table 8 Results of analysis of energetic and exergetic use to plot in Grassman diagram. The Comparison with a research of Sairam and Kaushik [13] is presented that the boiler has the greatest destruction exergy 1196 MW.

Conclusion
The