Fall 2019

Table of Contents
Chapter 1 ................................................................................................................................................. 5
Introduction ............................................................................................................................................. 5
1.1
Objectives ......................................................................................................................... 5
1.2 Coal Mines in Afghanistan ............................................................................................... 5
1.3 Bamiyan Province ............................................................................................................ 7
1.4 Kahmard district ............................................................................................................... 8
1.5 Coal mines in Bamyan ..................................................................................................... 8
1.6 Kahmard coal mine .......................................................................................................... 9
Chapter 2 ............................................................................................................................................... 10
Load Study and Site selection ............................................................................................................... 10
2.1 What is Coal Thermal Power plant? ....................
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2.2 Site selection and Load Study ..............................
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2.2.1 Ghazni Provinces ................................................................................................................. 10
2.2.1.1 Infrastructure ................................................................................................................. 11
2.2.1.2 Load of Ghazni province: .............................................................................................. 11
2.2.2 Wardak Province .................................................................................................................. 12
2.2.2.1 Network expansion.
...................................................................................................... 13
1

Table of Figures
2

List of Tables
3

4

Chapter
1
Kahmard coal mineshaft was found by Russia and its extraction was begun during the system of ruler Zahir Shah. Exhuming of the dig proceeded wrongfully for multi decade. Be that as it may, after agreement with the Chinese organization, MCC, its extraction had been stopped.
Kahmard coal mining has been contracted with MCC which utilized for control age of Aynak copper mine in Logar territory. Kahmard coal isn't seen as that much valuable or significant as far as quality and amount as a result of the multifaceted nature of the mine. Its extraction looked with numerous issues. Its coal saves have been evaluated at 500,000 tons. Be that as it may, the mine has been separated illicitly for a considerable length of time. Designer Mohammad
Karim Omid, head of Ashpostah mine, said both the legislature and the individuals extricated mines to the measure of 23,000 tons of coal month to month. The gatherings engaged with its unlawful extraction were paying 1,500 Afghanis for every ton to the administration.
Mohammad Hadi Saighani, Kahmard area boss, said the careful measure of coal saves was not recognized however when the mine was separated 200 trucks were stacked and moved to various urban areas day by day. "We don't have a clue what number of huge amounts of coal of exists there, however consistently just 160,000 tons of coal removed from the AshPoshtah mine," he included. Service of Mines obstructed the Kahmard coal mineshaft two years prior.
However, extraction procedure of Saighan and Yakawlang extraction couldn't be begun at this point. The Ministry of Mine would declare delicate for the coal mineshaft in Sar-I-Murgh zone of Yakawlang region [1].
1.1
Objectives
֍ To find the potential of mines in Bamiyan for a coal-fired power plant.
֍ Site selection of constructing the coal-fired power plant in Bamiyan.
֍ Assessing the load demand of the neighbor provinces.
֍ Find the distance between the power plant in Bamiyan and the electricity feeder sites.
֍ Determining the capacity of Kahmard coal mine.
֍ Design of coal-fired power plant using Kahmard coal mine in Bamiyan.
1.2 Coal Mines in Afghanistan
Afghanistan has moderate to potentially abundant coal resources. Much of the coal is relatively deep or currently inaccessible, however, and the scale of development has been limited.
Indigenous coal has been used in Afghanistan for small industry (notably in the manufacturing of cement and textiles, and in food processing), and as a primary source of household fuel in both raw and briquetted forms. Electrical generation from coal has occurred only on a temporary basis when coal was used as a substitute fuel for generation by natural gas. The main factors limiting the more widespread use of coal in the past appear to have been the rugged terrain of the country, the lack of a transportation network to deliver coal, and the absence of an industrial infrastructure to utilize the coal. In addition, the geology of Afghan coal is poorly understood, and much of the known coal occurs in structurally deformed areas where exploitation can be difficult [2].
5

The U.S. Geological Survey (USGS) is conducting a cooperative coal resource assessment of
Afghanistan with the Afghan Ministry of Mines and Industries (MMI). The assessment is one component of a much larger program that the USGS is conducting in Afghanistan under the auspices of the U.S. Agency for International Development (USAID). The various agencies of
MMI involved in this cooperative effort include the Afghan Geological Survey (AGS), the
North Coal Department (NCD), and the Coal Mines Section of the Mining Affairs Department.
The objectives of the assessment are to determine the quality, quantity, and distribution of coal throughout Afghanistan, and to develop the indigenous capability for refining the assessment on a sustainable basis. The assessment will determine the stratigraphic and areal extent of coal in Afghanistan, and quantify the coal resource on a regional and national level. The coal will be classified for its characteristics as a fuel or other beneficial uses, as well as for the attributes that could affect the natural environment, either in situ or from utilization. Special attention will be paid to determining the prospects for shallower and less structurally deformed coals than to those that have been mined to date. The potential for the commercial recovery of methane from coal mines and coal beds will also be assessed. Although the primary focus of the assessment will be to work with MMI to quantify and characterize the coal resources in place, the work will be conducted in close cooperation with other governmental and nongovernmental stakeholders to assure that the Afghan coal mining sector can be developed on a safe and sustainable basis that is environmentally sound and economically rational. Coal reserves of Afghanistan are estimated to be 73 million tons. Current coal production in
Afghanistan is estimated to be about 220,000 tons per year [2].
Figure 1: Distribution of major coal-bearing rocks in Afghanistan [2] .
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The depth and extent of the coal-bearing rocks shown in this figure are, for the most part, inferred from a very limited set of data for the existing mines and other reported occurrences.
The distinction between shallow and deep coals is somewhat arbitrary and is drawn at the approximate top of the Mesozoic at the surface. The deeper coal areas are considered prospectively valuable for coal-bed methane (CBM). The shallower coal areas could have commercial potential for underground mining, CBM, and to a limited extent, surface mining. The major mines shown on the map are generalized locations of government mines that have operated in the past. Some of these are operational today, either by the government or by unsanctioned operators reworking the deposit. The Paleogene coalbearing rocks shown on this figure are generally quite deformed, but have been mined for local use and could have CBM potential. The coal-bearing rocks shown here also may be source rocks for conventional petroleum accumulations.
1.3 Bamiyan Province
Bamyan Province is one of the thirty-four provinces of Afghanistan, located in the central highlands of the country. Its terrain is mountainous or semi-mountainous. The province is divided into eight districts, with the town of Bamyan serving as its capital. The province has a population of about 455,000 [1].
Mountains cover ninety percent of the province, and the cold, long winter, lasting for six months, brings temperatures of three to twenty degrees Celsius below zero. Mainly Daizangi
Hazara people live in the area. Transportation facilities are increasing, but sparse. Notably
Figure 2: Bamiyan province [Bukhdi news].
Bamyan is now connected by road to Kabul through Parwan province and through Maidan
Wardak. The connection between Maidan Shar and Bamyan – 136 km long – makes it possible to reach Kabul in a 2-hour drive. The connection is almost completed missing just 15 km of paving The main crops are wheat, barley, mushung, and baquli, grown in spring. When crops are damaged by unusually harsh weather, residents herd their livestock down to Ghazni and
Maidan provinces to exchange for food. Bamyan's climate is transitional between cold arid and semi-arid, with cold winters and warm, dry summers [1] .
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1.4 Kahmard district
There are coal mines in Kohmard District. Kohmard is one of the remote districts of Bamyan, lying close to the border with northern Jowzjan province. A large number of workers have been employed at the mines.
Kahmard is a district of Bamyan Province in central Afghanistan. It is located at an altitude of 1,475 meters, with a population of 31.042. Kahmard is situated 140 km from Bamiyan city, in the north of the province, and is divided into five valleys (Hajar, Madr, Tangipushta, Ashpusht and DoAb-e-Mekh-I-
Zarin). Tajiks are around 85% of the population and make up the majority in the district, followed by
8% Hazaras, 6% Tatars and a small minority of Pashtuns.
It was part of Baghlan Province in the past, but in 2005, part of the district was split off to form Sayghan
District. The main river, the Ajar, is an important source of water for the district. Kahmard is considered to be relatively rich. In the past, the district was a hunting ground of the former King (Zahir Shah). No major destruction of houses, shops, education or health centers took place during the war.
Kahmard has been shaken by rivalries and armed conflicts between Toofan, an ethnic Tajik and former
Governor allied to Khalili, and Commander Rahmatullah allied to Mawlawi Islamuddin, Governor of
Samangan Province. In mid-June 2002, after fighting between the opposing factions, the district fell to commander Rahmatullah, affiliated with Jamiat and closely involved with the Taliban during the war.
Human rights violations have been reported in various parts of the district. Commander Atiq
Saighani took control of Kahmard district on September 26, 2006. Workers sacked from the
Kohmard coal mine (Kilij and Eshposhta mine) had joined Taliban militants and thus the number of armed insurgents increased. A Chinese company will construct a coal power plant to light Kohmard and utilize in Aynak copper mine. 300 tunnels of the Kohmard coal mine had been shut down in line with the decision of ministers’ council because they were used illegally by powerful figures [1].
Precipitation mostly falls in late winter and spring and air temperature is varying as bellow table.
Table 1: Temperature of Bamiyan province in different months [Wikipedia].
1.5 Coal mines in Bamyan
The central Bamyan province is though a mountainous region, it is rich in natural resources such as iron and coal mines. Following its extraction in a nonprofessional and nontechnical way, the Ministry of Mines had to block most of coal mines in the province.
8

Kahmard-o-Saighan and Yakawlang districts are rich in coal mines. Kahmard coal mine is located in Kalich, Ashposhtah, Chartaq Karimak and Doab Mikh Zarin areas.
1.6 Kahmard coal mine
Kahmard coal mine was discovered by Russia and its extraction was started during the regime of king Zahir Shah. Excavation of the mine continued illegally for one decade. However, after contract with the Chinese company, MCC, its extraction had been halted.
Figure 3: Bamyan province [Pajhwak Afghan News].
Kahmard coal mining has been contracted with MCC which used for power generation of
Aynak copper mine in Logar province. Kahmard coal is not viewed as that much precious or important in terms of quality and quantity because of the complexity of the mine. Its extraction faced with many problems. Its coal reserves have been estimated at about 500,000 tons.
However, the mine has been extracted illegally for years.
Engineer Mohammad Karim Umid, head of Ashpostah mine, said both the government and the people extracted mines to the amount of 23,000 tons of coal monthly. The groups involved in its illegal extraction were paying 1,500 Afghanis per ton to the government.
Mohammad Hadi Saighani, Kahmard district chief, said the exact amount of coal reserves was not identified but when the mine was extracted 200 trucks were loaded and transferred to different cities daily. “We do not know how many tons of coal of exists there, but every year only 160,000 tons of coal extracted from the Ash Poshtah mine,” he added.
Ministry of Mines blocked the Kahmard coal mine two years ago. But extraction process of
Saighan and Yakawlang extraction could not be started yet. The Ministry of Mine would announce tender for the coal mine in Sar-i-Murgh area of Yakawlang district [1].
9

Chapter
2
In the following project we have selected the neighboring provinces of Bamyan to supply them electricity from coal-fired power plant of Bamyan which includes: Ghazni, Wardak,
Daykondi and each of them are determined in details according to their load demands as follow:
2.1. Ghazni Province
Ghazni province is located on Kabul-Kandahar highway. Maidan Wardak and Bamyan provinces are in the north of the province, Paktia, Paktika and Logar provinces are in the east,
Zabul is in the south and Urozgan and Zabul provinces are bordering the province in the west.
The area of Ghazi province is 23812 Km 2 and Ghazni city is the center of Ghazni province.
The total population of Ghazni Province is 1249376. 3 tribes (Tajik, Pashtun, Hazara and Sikh) are consisting the Population. Ghazni has 18 districts, listed below: Malistan, Ajristan,
Jaghoori, Nawar, Rasheedan, wayiz, Jaghato, Wali Mohammad Shaheed, Khwaja Omari,
Zankhan, Deh Yak, Andar, Qarabagh, Geero, Abband, Muqur, Gaillan and Nawa.
Figure 4: Ghazni Province in Afghanistan map [7].
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As of 2013, the total population of the province is about 1368800, which is multi-ethnic and mostly a tribal society. According to the Institute of the Study of War, Ghazni has nineteen districts and is one of the most ethnically diverse provinces in Afghanistan [7].
2.1.1 Infrastructure
The Sardeh Band Dam is located in Andar District near the border with Paktika Province. It creates a large water reservoir that is critical to the irrigation of the Kahnjoor farming zone.
The dam itself and the canal system it feeds both need repairs and maintenance. Governor Musa
Khan Akbarzada stated that key development projects would be launched in southern Ghazni in 2012 ahead of the Asian capital of the Islamic cultural centre, a mosque, a covered bazaar, a gymnasium, a guesthouse, an airport, a five-star hotel and two 27 storey-buildings and others.
More than 2000 people would find work opportunities on the $30 million projects; $10 million would be provided by the central government, $7 million by the Polish provincial reconstruction team (PRT) and $3 million by the US. A 40-kilometere road would be asphalted by the end of the 2012.Ghazni province is to be connected to the national electrical distribution system via North-East Power System (NEPS). The construction of transmission line would begin from east Chimtala to Ghazni using high voltage transmission network (2*220 KV transmission lines and power substations). The project is to be implemented by USFOR-A and
USAID costing $101 million. However the Asian Development Bank agreed to complete the transmission line from Chimtala to Dast-i-Barchi; hence reducing Project scope to begin from
Dast-i-Barchi instead of Chimtala. The implementation of this project was delayed due to
USACE being unable to award a contract because bids received for the project were more than double estimated costs, due largely to Security concerns resulting from the risks associated with implementing firm-fixed-price contracts in a kinetic environment, poor cost estimates, and unrealistic periods of performance. USACE is reproducing both projects and plans to award contracts in June or July 2012, which will delay the project’s execution schedules between 6 and 15 months. Furthermore, the delays in transferring funds contributed to delays in project execution. This line is a key part of a planned NEPS to SEPS connection to transport power to Kandaharto replace the expensive diesel-fueled power plants [8].
2.1.2 Load calculation of Ghazni province:
Peak load for Ghazni province is expected at 100 MW and the connection rate will reach 70%
In 2032, as given in Table 2.
The load centers in Ghazni province are along the ring road A1 from Kabul to Kandahar and
The tentatively proposed locations of the new substations are given in the following table.
Electrification could come from the NEPS to SEPS connector. One substation will be at the capital, Ghazni. This substation will also be used to feed a load at Sharan in Paktika province at the 110 kV level. Two other substations along the NEPS to SEPS connector will be at
Quarabagh and Gelan. Gelan will also be used to feed a load in Paktika province.
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Table 2: Load demand load forecasts of Ghazni.
Year
Population [Thousand]
No of Households [Thousand]
Connection rate [%]
Gross Electricity Demand [GWh ]
Net Electricity Demand [GWh]
Peak Demand [MW]
Load and load forecast for Ghazni
2010 2011
1130.1 1149.4
116.6
2.4
2.2
1.5
0.5
118.9
3
2.9
2
0.6
2012
-
121.3
8.3
8.5
5.9
1.8
2015
-
128.7
23.9
32.4
23.1
6.7
2020
-
142.1
50
167.5
124.4
34.8
2.2 Wardak Province
Wardak Province, also called Wardag or simply Wardak, is one of the 34 provinces of
Afghanistan, located in the central region of Afghanistan. It is divided into eight districts and has a population of approximately 567,600. The capital of the province is Maidan Shar, while the most populous district in the province is Saydabad District [9]. Total area of Wardak is
2032
-
156.5
58.3
280.2
213.7
58.2
Figure 5: Maidan Wardak [Pashtun Valley].
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9934 km2 which consists of eight districts (Chaki Wardak, Day Mirdad, Hisa-I-Awali Bihsud,
Jaghatu, Jalrez, Markazi Bihsud, Maidan Shar, Nirkh and Saydabad) [10].
2.2.1 Load calculation of Wardak province.
Currently, Wardak province is not supplied from the national transmission grid of Afghanistan.
Only 4% of households were connected to the power supply from an isolated generation unit in 2011. According the load forecast for the province, peak demand will increase to 47 MW in
2032 and the connection rate will reach 70% [10].
Table 3: Load Demands and load forecasts for Wardak.
Year
Population [Thousand]
No of Households [Thousand]
Connection rate [%]
Gross Electricity Demand [GWh ]
Net Electricity Demand [GWh]
Peak Demand [MW]
2010
549.2
55.1
0.0
3.0
2.0
0.6
Load and load forecast for Wardak
2011
558.4
2012
-
2015
-
2020
-
56.2
4.0
5.3
3.6
1.1
57.3
9.1
12.3
8.5
2.6
60.8
24.2
37.4
26.6
7.8
67.2
50.0
101.4
75.6
21.1
2.3 Daikundi
Daikundi was recognized as a separate province nine years ago. Earlier, it was a district of
Uruzgan province. Daikundi province lies at a distance of 460-kilometres to the west of country’s capital and surrounded by Uruzgan to its southwest, Bamyan to the east, Ghor to the north, Ghazni to the south and Helmand province to the northwest. The population of this province has more than 729, 000 individuals. It has a total 17501 Km
2 area. It is located 2, 400 meters above the sea level. The mountainous province has some plain areas. It has hot as well as cold seasons. Due to heavy snowfall in the winter, the roads remain blocked for months, cutting the communication of the province with rest of the country. Daikundi’s provincial has a total 780 square kilometers area with a total population of 95,000 inhabitants and 165 villages.
2032
-
70
70
247.5
192.2
47.1
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Figure 6: Daikundi Province.
2.3.1 Districts
Daikundi has nine administrative unites including the provincial capital Nieli. Besides provincial capital the province has eight districts include Ashtarly, Khijran, Khedir, Kitti,
Miramor, Sang Takh Shahristan and Gizab.
2.3.2 Dam
Despite the flow of three rivers and opportunity to reserve water, the province is still deprived of dams. Being a mountainous region, the province has suitable locations for construction of water dams.
2.3.3 Industry
The women folk of the province take active part in handicraft industry of the province since long. They weave carpet, coverlet, embroidery, designing and other kinds of clothes to feed their large families. Residents of the province are skilled. After import of carpet material from
Kabul, people now prefer to weave carpets based on modern designing, keeping in mind the growing market demand. The iron industry in the province is still functioning, which manufactures necessary tools for the local farmers.
2.3.4 Agriculture
Almost 90% of the resident’s economy depends on agriculture and livestock in the province.
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The widely cultivated crops of the province include wheat, barley, and corn while almond, apple and apricot are the most produced fruit in the province. The production of almond crops in 2012 reached to 7, 500 tons; however, the officials said that insufficient rains caused reduction in the crop during in the current year. The wheat crops does not meet the growing demands of the province that’s why people direly needed export of rice, cooking oil, beans and peas from Ghazni and Kabul provinces. The residents face shortage of wheat every year because the transportation roots remain blocked due to heavy snowfall.
2.3.5 Load of Daikundi province
The province of Daykundi is located in central Afghanistan. Currently, there is no power supply from the national grid of Afghanistan. Peak demand in Daykundi is expected at about 30 MW with a connection rate of 65% of households. The population is spread over the mountainous area, but the major load is expected to be around Nili, the capital of the province, and around
Gizab. With construction of Olambagh HPP between 2025 and 2032, connection of this load center to the national grid will be possible. The routing of the 110 kV line between Olambagh and Nili must be chosen in a way to connect other larger towns, such as Gizab. And Table 4 shows the load and load forecast for Daikundi province.
Table 4: Load and load forecast for Daikundi.
Year
Load and load forecast for Daikundi
2010 2011 2012 2015 2020 2032
Population [Thousand] 424.1 431.3 -
No of Households
[Thousand]
Connection rate [%]
42.6
0.0
43.4
0.0
44.3
0.0
-
47
10
-
51.9
35
-
57.1
53.3
Gross Electricity Demand
[GWh]
Net Electricity Demand
[GWh]
Peak Demand [MW]
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
2.3
1.6
0.5
29.9
22.2
6.2
78.5
59.9
16.3 0.0
2.4 Bamiyan province
Electricity demand is the most important part of design. In this section we calculate the electricity demand of Bamyan Province. Bamyan province is located in the center of
Afghanistan. Currently, Bamyan province is not connected to the transmission network of
Afghanistan. The demand forecast for Bamyan province in Table 5 indicates an increase from zero to a peak load of about 28 MW in 2032 [9].
15

Year
Population [thousand]
No of households
[thousand]
Connection rate [%]
Gross electricity demand
[GWH]
Net electricity demand
[GWH]
Peak demand [MW]
Table 5: Load and load forecast for Bamyan [9] .
2010 2011 2012 2015 2020 2025 2032
411.7 418.5
41.9 42.6 43.5 46.1 50.9 56 63.3
0.3
0
0
0
0
0
0
0
0
0
0
0
10
2.3
1.6
0.5
35
29.4
21.8
6.1
53.3
77.1
58.8
16
65
148.9
116.1
28.3
16

Chapter
3
3.1 Thermodynamic cycles
A thermodynamic cycle consists of a series of thermodynamic processes transferring heat and work, while varying pressure, temperature, and other state variables, eventually returning a system to its initial state. In the process of going through this cycle, the system may perform work on its surroundings, thereby acting as a heat engine. State quantities depend only on the thermodynamic state, and cumulative variation of such properties adds up to zero during a cycle. Process quantities (or path quantities), such as heat and work are process dependent, and cumulative heat and work are non-zero. The first law of thermodynamics dictates that the net heat input is equal to the network output over any cycle. The repeating nature of the process path allows for continuous operation, making the cycle an important concept in thermodynamics. Thermodynamic cycles often use quasistatic processes to model the workings of actual devices [10].
3.2 Heat and Work
Two primary classes of thermodynamic cycles are power cycles and heat pump cycles. Power cycles are cycles which convert some heat input into a mechanical work output, while heat pump cycles transfer heat from low to high temperatures using mechanical work input. Cycles composed entirely of quasistatic processes can operate as power or heat pump cycles by controlling the process direction. On a pressure volume diagram or temperature entropy diagram, the clockwise and counterclockwise directions indicate power and heat pump cycles, respectively [10].
3.2.1 Relationship to work
Because the net variation in state properties during a thermodynamic cycle is zero, it forms a closed loop on a PV diagram. A PV diagram's Y axis shows pressure (P) and X axis shows volume (V). The area enclosed by the loop is the work (W) done by the process: [10]
Example of P-V diagram of a thermodynamic cycle.
Figure 7: P-V diagram of a thermodynamic cycle [10] .
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This work is equal to the balance of heat (Q) transferred into the system:
Equation (2) makes a cyclic process similar to an isothermal process: even though the internal energy changes during the course of the cyclic process, when the cyclic process finishes the system's energy is the same as the energy it had when the process began. If the cyclic process moves clockwise around the loop, then W will be positive, and it represents a heat engine. If it moves counterclockwise, then W will be negative, and it represents a heat pump [10].
3.2.2 Power cycles
Thermodynamic power cycles are the basis for the operation of heat engines, which supply most of the world's electric power and run almost all motor vehicles. Power cycles can be divided according to the type of heat engine they seek to model. The most common cycles that model internal combustion engines are the Otto cycle, which models gasoline engines and the
Diesel cycle, which models diesel engines. Cycles that model external combustion engines include the Brayton cycle, which models gas turbines, and the Rankine cycle, which models steam turbines [10].
Figure 8: Heat engine diagram.
The clockwise thermodynamic cycle indicated by the arrows shows that the cycle represents a heat engine.
The cycle consists of four states (the point shown by crosses) and four thermodynamic processes (lines) [10].
If no volume change happens in process 4->1 and 2->3, equation (3) simplifies to:
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3.2.3 Heat pump cycles
Thermodynamic heat pump cycles are the models for heat pumps and refrigerators. The difference between the two is that heat pumps are intended to keep a place warm while refrigerators are designed to cool it. The most common refrigeration cycle is the vapor compression cycle, which models systems using refrigerants that change phase. The absorption refrigeration cycle is an alternative that absorbs the refrigerant in a liquid solution rather than evaporating it. Gas refrigeration cycles include the reversed Brayton cycle and the Hampson-
Linde cycle. Regeneration in gas refrigeration allows for the liquefaction of gases [10].
3.3 Well-known thermodynamic cycles
Table 6: Well-known thermodynamic cycles [11] .
3.3.1 Ideal cycle
An ideal cycle is constructed out of:
1. TOP and BOTTOM of the loop: a pair of parallel isobaric processes.
2. LEFT and RIGHT of the loop: a pair of parallel isochoric processes [11].
Figure 9: An illustration of an ideal cycle heat engine (arrows clockwise) [11] .
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3.3.2 Carnot cycle
The Carnot cycle is a cycle composed of the totally reversible processes of isentropic compression and expansion and isothermal heat addition and rejection. The thermal efficiency of a Carnot cycle depends only on the absolute temperatures of the two reservoirs in which heat transfer takes place, and for a power cycle is:
Where is the lowest cycle temperature and the highest. For Carnot power cycles the coefficient of performance for a heat pump is:
And for a refrigerator the coefficient of performance is:
The second law of thermodynamics limits the efficiency and COP for all cyclic devices to levels at or below the Carnot efficiency. The Stirling cycle and Ericsson cycle are two other reversible cycles that use regeneration to obtain isothermal heat transfer.
Figure 10: PV diagram of a Carnot cycle [11] .
3.3.3 Stirling cycle
A Stirling cycle is like an Otto cycle, except that the adiabats are replaced by isotherms. It is also the same as an Ericsson cycle with the isobaric processes substituted for constant volume processes [11].
1. TOP and BOTTOM of the loop: a pair of quasi-parallel isothermal processes
2. LEFT and RIGHT sides of the loop: a pair of parallel isochoric processes
Heat flows into the loop through the top isotherm and the left isochore, and some of this heat
20

flows back out through the bottom isotherm and the right isochore, but most of the heat flow is through the pair of isotherms. This makes sense since all the work done by the cycle is done by the pair of isothermal processes, which are described by Q=W. This suggests that all the net heat comes in through the top isotherm. In fact, all of the heat which comes in through the left isochore comes out through the right isochore: since the top isotherm is all at the same warmer temperature T
H
and the bottom isotherm is all at the same cooler temperature T
C
, and since change in energy for an isochore is proportional to change in temperature, then all of the heat coming in through the left isochore is cancelled out exactly by the heat going out the right isochore [11].
3.4 Steam Generators
A steam generator is a form of low water-content boiler, similar to a flash steam boiler. The usual construction is as a spiral coil of water-tube, arranged as a single, or monotube, coil.
Circulation is once-through and pumped under pressure, as a forced-circulation boiler. The narrow-tube construction, without any large-diameter drums or tanks, means that they are safe from the effects of explosion, even if worked at high pressures. The pump flowrate is adjustable, according to the quantity of steam required at that time. The burner output is throttled to maintain a constant working temperature. The burner output required varies according to the quantity of water being evaporated: this can be either adjusted by open-loop control according to the pump throughput, or by a closed-loop control to maintain the measured temperature.
3.4.1 Super Heater
A super heater is a device used to convert saturated steam or wet steam into superheated steam or dry steam. Superheated steam is used in steam turbines for electricity generation, steam engines, and in processes such as steam reforming. There are three types of super heaters: radiant, convection, and separately fired. A super heater can vary in size from a few tens of feet to several hundred feet (a few meters to some hundred meters). Super heaters are one of the most important accessories of boiler that improves the thermal efficiency. In super heaters there should not be any fins as it increases the thermal stresses and carful should be taken when choosing the super-heater material that is stand for high temp and corrosion resistance.
Figure 11: A water tube boiler with super heater.
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3.4.2 Economizer
The economizer is the heat exchanger that raises the temperature of the water leaving the highest-pressure feed-water heater to the saturation temperature corresponding to the boiler pressure, which is done by the gases leaving the last super-heater or reheater that still have enough heat to transfer before it leaves to the stack, that is why it is called economizer.
Economizer tubes are commonly 1.75-2.75 inch in OD and made in vertical sections of continuous tubes, between inlet to outlet headers, with each section formed into several horizontal paths connected by 1800 bend for proper drainage. Sections are placed side by side on 1.75-2-inch. The spacing depends on the fuel type, as the smaller ashes the cleaner the fuel such as the natural gas. Economizer are come plain or with extended surfaces to enhance heat transfer. Economizers are generally placed between the last super heater re-heater and the air pre-heater. Economizers functions well with feed-water heater, as without them cold water is entering the economizer, which results in condensation and corrosion at the outer surfaces.
Using the deaerating (DA) feed water heater is considered beneficial for the economizer as it releases most of the oxygen that may react and cause fouling. Chemical and water washing when cleaning the economizer in the shut down time of the station.
3.4.3 Re-heaters
They are the same as the super-heaters but as their exit temperature is a little bite less than super-heaters and their pressure is 20%-25% less than the super-heater, they can stand less quality material alloys.
3.5 Steam Turbine
A steam turbine is a device that extracts thermal energy from pressurized steam and uses it to do mechanical work on a rotating output shaft. Its modern manifestation was invented by Charles Parsons in 1884. The steam turbine is a form of heat engine that derives much of its improvement in thermodynamic efficiency from the use of multiple stages in the expansion of the steam, which results in a closer approach to the ideal reversible expansion process. Because the turbine generates rotary motion, it is particularly suited to be used to drive an electrical generator about 85% of all electricity generation in the United States in the year 2014 was by use of steam turbines.
Steam turbines are made in a variety of sizes ranging from small 0.75 kW units used as mechanical drives for pumps, compressors and other shaft driven equipment, to 150 MW turbines used to generate electricity. Steam turbines are widely used for marine applications for vessel propulsion systems. In recent times gas turbines, as developed for aerospace applications, are being used more and more in the field of power generation once dominated by steam turbines [12].
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Figure 12: Steam Turbine.
3.5.1 History
The first device that may be classified as a reaction steam turbine was little more than a toy, the classic Aeolipile, described in the 1st century by Hero of Alexandria in Roman Egypt. In
1551, Taqi al-Din in Ottoman Egypt described a steam turbine with the practical application of rotating a spit. Steam turbines were also described by the Italian Giovanni Branca (1629) and John Wilkins in England (1648). The devices described by Taqi al-Din and Wilkins are today known as steam jacks. In 1672 an impulse steam turbine driven car was designed by Ferdinand Verbiest. A more modern version of this car was produced some time in the late
18th century by an unknown German mechanic. In 1775 at Soho James Watt designed a reaction turbine that was put to work there. In 1827 the Frenchmen Real and Pichon patented and constructed a compound impulse turbine [12].
The modern steam turbine was invented in 1884 by Charles Parsons, whose first model was connected to a dynamo that generated 7.5 kilowatts (10.1 hp) of electricity. The invention of
Parsons' steam turbine made cheap and plentiful electricity possible and revolutionized marine transport and naval warfare. Parsons' design was a reaction type. His patent was licensed and the turbine scaled-up shortly after by an American, George Westinghouse. The Parsons turbine also turned out to be easy to scale up. Parsons had the satisfaction of seeing his invention adopted for all major world power stations, and the size of generators had increased from his first 7.5 kilowatts (10.1 hp) set up to units of 50,000 kilowatts (67,000 hp) capacity. Within
Parson's lifetime, the generating capacity of a unit was scaled up by about 10,000 times, and the total output from turbo-generators constructed by his firm C. A. Parsons and Company and by their licensees, for land purposes alone, had exceeded thirty million horse-power.
3.5.2 Principle
The steam energy is converted mechanical work by expansion through the turbine. The expansion takes place through a series of fixed blades (nozzles) and moving blades each row of fixed blades and moving blades is called a stage. The moving blades rotate on the central turbine rotor and the fixed blades are concentrically arranged within the circular turbine casing which is substantially designed to withstand the steam pressure [13].
The main components of a steam turbine are:
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
Feed water pump

Boiler

Turbine stages, comprising nozzle/stator and rotor blade rows

Condenser
3.5.3 Classification of Steam Turbines
Steam turbines may be classified into different categories depending on their construction, the process by which heat drop is achieved, the initial and final conditions of steam used and their industrial usage as follows: [13]
A. According to the Number of pressure stages:

Single-stage turbines with one or more velocity stages usually of small power capacities, mostly used for driving centrifugal compressors, blowers and other similar machinery.

Multistage impulse and Reaction turbines, made in a wide range of power capacities varying from small to large.
B. According to the direction of steam flow:

Axial turbines, in which the steam flows in a direction parallel to the axis of the turbine.

Radial turbines, in which the steam flows in a direction perpendicular to the axis of the turbine. One or more low pressure stages in such turbines are made axial.
C. According to the Number of cylinders:

Single cylinder turbines

Multi cylinder (2, 3 and 4 cylinders) turbines, which can have single shaft, i.e. rotors mounted of the same shaft, or multiaxial, having separate rotor shaft and have their cylinders placed parallel to each other.
D. According to the method of governing:

Turbines with nozzle governing.

Turbines with bypass governing in which steam besides being fed to the first stage is also directly led to one, two or even three intermediate stages of the turbine.
E. According to the Principle of Action of Steam:

Impulse turbines.

Axial Reaction turbines.

Radial reaction turbines without any stationary guide blades.

Radial reaction turbines having stationary guide blades.
F. According to the Heat Drop Process:

Condensing turbines with exhaust steam let into condenser with Regenerators,
Condensing turbines with one or two intermediate stage extractions at specific pressures for industrial and heating purposes.

Back pressure turbines, the exhaust steam from which is utilized for industrial and heating purposes.

Back-pressure turbines with steam extraction from intermediate stages at specific pressures.
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
Low-pressure (Exhaust pressure) turbines in which the exhaust steam from reciprocating steam engines, power hammers, presses, etc is utilized for power generation.

Mixed-pressure with two or three pressure extractions with supply of exhaust steam to its intermediate stages [2].
G. According to the Steam Conditions at inlet:

Low-pressure turbines using at pressures 1.2 to 2 ata.

Medium-pressure turbines using steam at pressure up to 4.0 ata.

High-pressure turbines using steam at above40 ata.

Very high pressure turbines using steam up to 40 ata and higher pressure and temperature.
H. According to their Usage in industry:

Stationary turbines with constant speed of rotation primarily used for driving alternators.

Stationary turbines with variable speeds meant for driving turbo blowers, air circulators, pumps etc.

Non stationary turbines with variable speeds employed in steamers, ships, railway
(turbo) locomotives etc. [13].
3.5.6 Turbine Selection:
In all fields of application, the competitiveness of a turbine is a combination of several factors:

Efficiency

Life

Power density (power to weight ratio)

Direct operation cost

Manufacturing and maintenance costs
3.6 Condenser
Condenser is an important component of any refrigeration system. In a typical refrigerant condenser, the refrigerant enters the condenser in a superheated state. It is first de-superheated and then condensed by rejecting heat to an external medium. The refrigerant may leave the condenser as a saturated or a sub-cooled liquid, depending upon the temperature of the external medium and design of the condenser.
Figure 13 shows the variation of refrigeration cycle on T-s diagram. In the figure, the heat rejection process is represented by 2-3’-3-4. The temperature profile of the external fluid, which is assumed to undergo only sensible heat transfer, is shown by dashed line. It can be seen that process 2-3’ is a de-superheating process, during which the refrigerant is cooled sensibly from a temperature T2 to the saturation temperature corresponding condensing pressure, T3’. Process 3’-3 is the condensation process, during which the temperature of the refrigerant remains constant as it undergoes a phase change process. In actual refrigeration systems with a finite pressure drop in the condenser or in a system using a zeotropic refrigerant mixture, the temperature of the refrigerant changes during the condensation process also.
However, at present for simplicity, it is assumed that the refrigerant used is a pure refrigerant
(or an azeotropic mixture) and the condenser pressure remains constant during the
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condensation process. Process 3-4 is a sensible, sub cooling process, during which the refrigerant temperature drops from T 3to T4. [14]
Figure 13: Refrigeration cycle on T-s diagram [2].
3.6.1 Classification of condensers
Based on the external fluid, condensers can be classified as: a) Air cooled condensers b) Water cooled condensers, and c) Evaporative condensers
3.6.1.1 Air-cooled condensers:
As the name implies, in air-cooled condensers air is the external fluid, i.e., the refrigerant rejects heat to air flowing over the condenser. Air-cooled condensers can be further classified into natural convection type or forced convection type [14].
3.6.1.2 Evaporative condensers:
In evaporative condensers, both air and water are used to extract heat from the condensing refrigerant. Figure 14 shows the schematic of an evaporative condenser. Evaporative condensers combine the features of a cooling tower and water-cooled condenser in a single unit. In these condensers, the water is sprayed from top part on a bank of tubes carrying the refrigerant and air is induced upwards. There is a thin water film around the condenser tubes from which evaporative cooling takes place. The heat transfer coefficient for evaporative cooling is very large. Hence, the refrigeration system can be operated at low condensing temperatures (about 11 to 13 K above the wet bulb temperature of air). The water spray counter
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current to the airflow acts as cooling tower. The role of air is primarily to increase the rate of evaporation of water. The required air flow rates are in the range of 350 to 500 m3/h per TR of refrigeration capacity [14].
Figure 14: Schematic of an evaporative condenser [3].
3.6.1.3 Water Cooled Condensers
In water cooled condensers water is the external fluid. Depending upon the construction, water cooled condensers can be further classified into:
1. Double pipe or tube-in-tube type
2. Shell-and-coil type
3. Shell-and-tube type
3.7 Feed Water Pump
Pump is energy absorbing rotodynamic machinery transporting fluid from one place to another, being key parameter and heart of any industrial process plant as well as thermal and nuclear power plant, also used for dewatering and irrigation purpose. Boiler feed water pump feeds condensed return water against high steam pressure produces by the boiler. BFP normally are centrifugal type pump containing a wide number of operating parameters, operator requirement makes this system to work within parameter functioning by the manufacturer on high efficiency regimes. As pump is centrifugal type pump, water enters axially through impeller eye and exit
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radially. Generally, electric motor is used as prime mover to run the feed pump. To force water into boiler, the pump must generate sufficient pressure to overcome steam pressure developed by boiler [14].
3.7 Generator
Thermal power station burns the fuel and use the resultant heat to raise the steam which drives the turbo generator. The fuel may be fossil (coal; oil; natural gas) whichever fuel is used the object is same to convert the heat into mechanical energy by rotating a magnet inside the set of windings.
Turbo generator incorporated with most modern design concepts and constructional features, which ensure reliability, with constructional & operational economy. The generator is driven by directly coupled steam turbine at a speed of 3000rpm, the generator is designed for continuous operation at rated output [15].
3.8 Clean Carbon Technology
The energy available from coal or fuel energy content is the amount of extractable energy through combustion that can be converted in heat value. This energy value can be calculated with specific combustion environment and process of energy conversion for different grades of coal for most mature (Anthracite) to least mature (Pit) variety. Compared to other non-fossil fuels like bio-mass, bio-diesel or refuse derived fuel; coal combustibility is significantly varying due to nature and weathering of coal. Though coal consists primarily carbon, but it is an admixture of various other elements including incombustible mineral matters like sand and clay along water of crystallization and water adsorbed in the surface of coal particles due to weathering.
The amount of these other elements affects usefulness of the coal as a fuel. The quality of coal can be determined by its rank and grade. The energy content is determined by the carbon available in coal and the quantity of available carbon reduces from highest rank Anthracite to lowest grade Lignite coal. However, as an outcome of coal combustion several pollutants are generated like oxides of Nitrogen (NOx) and sulphur (SOx), incombustible particulate matters
(as suspended particulate matter – SPM in atmosphere), emission of poisonous trace elements
(like As, Cl, Hg, Ni, Pb) and above all the largest contributor of global greenhouse effect carbon dioxide beside acid rain and health hazards.
In 1920s, pulverized coal firing technology was introduced for producing power for greater efficiency and larger size units and it was quickly deployed worldwide. In this technology, coal was pulverized into a fine powder and burned inside the furnace with pressurized air. The pulverization allowed for a quick, more efficient, controlled burning of coal in the boilers producing steam at higher pressures and temperatures. With increasing steam temperature and pressure, the efficiency of the steam turbine (and hence, of electricity generation) increased.
Gradually pulverized coal injection technology is also applied in modern steel manufacturing process [12].
Today, the clean technology for generating energy is one the solution for future of our world so, for coal industries, there are much attempt to promote new clean coal technologies. Clean coal technology is a collection of technologies being developed in attempts to lessen the negative environmental impact of coal energy generation and to mitigate worldwide climate change. Clean coal technologies are being developed to remove or reduce pollutant emissions to the atmosphere.
Some of the techniques that would be used to accomplish this include chemically washing minerals and impurities from the coal, gasification, improved technology for treating flue gases
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. to remove pollutants to increasingly stringent levels and at higher efficiency, carbon capture and storage technologies to capture the carbon dioxide from the flue gas and dewatering lower rank coals (brown coals) to improve the calorific value, and thus the efficiency of the conversion into electricity. Concerns exit regarding the economic viability of these technologies and the timeframe of delivery, potentially high hidden economic costs in terms of social and environmental damage. And the cost and viability of disposing of removed carbon and other toxic matter [12].
Several different technological methods are available for the purpose of carbon capture as demanded by the clean coal concept:

Pre-combustion capture: this involves gasification of a feedstock (such as coal) to form synthesis gas, which may be shifted to produce a H2 and CO2-rich gas mixture, from which the CO2 can be efficiently captured and separated, transported and ultimately sequestered, this technology is usually associated with integrated Gasification
Combined Cycle process configurations.

Post-combustion capture: this refers to capture of CO2 from exhaust gases of combustion processes.

Oxy-fuel combustion: Fossil fuels such as coal are burned in a mixture of recirculated flue gas and oxygen, rather than in air, which largely eliminates nitrogen from the flue gas enabling efficient, low-cost CO2 capture.
Figure 15: Horizontal tube economizer [19].
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Chapter
4
3.1 Generator Selection (Electrical)
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Conclusion
From this project we conclude that for designing a thermal power plant which its fuel is based on coal, we need some specifics equipments and readinesses. for designing of coal-fired thermal power plant we have considered its location in Bamyan province and there can be constructed a beneficial thermal power plant because of existing some excellent coal mines and the sizable mine that we considered in our project is Kahmard coal mine, which this plant can supply the needs for electricity of Bamyan and also at the same time the electricity needs for its neighboring provinces around it, including: Ghazni, Wardak and Daikundi.so for doing such a project we have divided our project report into five chapters as follow:
In the first chapter we have general information about the coal mines Afghanistan after that about some informations about Bamyan province, its location, map, districts, and population as well as about the Kahmard district and also its coal mine which is located in this province, also we have determined our objectives about all the processes of this project.
Our second chapter is named load study and site selection which we have selected Bamyan province in its Kahmard district that is going to be constructed a coal-fried thermal power plant and also we have selected its three neighboring provinces with some brief introduction of them which power will be supplied to them such as: Ghazni, Wardak, and Daikundi, in the next step we have calculated their load demands for electricity as well as the demand forecasts of them.
In the third chapter we have explained the thermal power plant, thermodynamic cycles with their definitions, working principles, diagrams and some mathematical relation secondly about the thermal power plant components such as: Steam generators and it’s sub components like superheater and reheater, Economizer, and air heater, second component of a thermal power plant is steam turbine, condenser is third, fourth is feed water pump and the last component is generator which generates electricity.
In the fourth chapter all we done the sizing and calculations of them for and selected the necessary equipments used in our considerable coal-fired thermal power plant in Bamyan province, at the first step we have selected our electrical generator according to the total demand load of those four provinces (Bamyan, Ghazni, Wardak and Daikundi), secondly we have sized the required steam turbine, steam generator, condenser, and feed water pump.
And in the last chapter we have discussed about the environmental impacts of thermal power plant which includes: air pollution, demolition and harming of environment.
References
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[4] A. Karimi, "Kahmard District Bamyan Province," Afghan Biographies, Kabul , 2017.
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[13] A.Sudheer Reddy, MD.Imran Ahmed, T.Sharath Kumar, "Analysis Of Steam Turbines,"
International Refereed Journal of Engineering and Science, vol. 3, no. 2, p. 17, 2014.
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[18] "Georgia's Plant Scherer coal-fired power production method.," USGS, [Online]. Available: https://www.usgs.gov/media/images/georgias-plant-scherer-coal-fired-power-productionmethod.
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