Assignment 3: Performance Evaluation of Existing Powerplants;
MINERGY Diesel Power Plant
Carpio,Aivi Rose Denise, Napolis,Giankenneth I.
Department of Mechanical Engineering, University of the Philippines
Diliman, Quezon City

1. MINERGY Diesel Power Plant
1.1. Description The Mindanao Energy Systems, Inc. Diesel Power Plant is an independent power producer established in 1992. It is located at Barangay Tablon, Cagayan de Oro City. MINERGY DPP provides a portion of the power requirements of its sole customer and part-owner, the Cagayan Electric Power and Light Company, Inc. (CEPALCO), the electric distributor serving Cagayan de Oro City and the municipalities of Tagoloan, Villanueva and Jasaan in Misamis Oriental, including the 3,000 hectare PHIVIDEC Industrial Estate.
The diesel power plant consists of three (3) 6.3 Megawatt Bunker C-fired engine-generator sets having a total capacity of 18.9 MW. The power plant began commercial operations in June 1995 on an 18.9 MW capacity. The power plant’s performance is comparable with other modern and newly constructed diesel power plants of the same capacity in the country. Its engines are the well-known and highly reliable Sulzer brand manufactured under the license of new Sulzer Diesel Ltd. by Zgoda of Poland, while its alternators were supplied by the GEC Alsthom of France.
The Minergy’s mission is as follows: MINERGY’s Mission: “We are a Company dedicated to the pursuit of excellence. Towards this we affirm our commitment to the profitability of our stakeholder’s investments and the full satisfaction of our customers. The growth, safety and general well-being of our human resources as well as the community and environment will continue to be the core of our development programs. To achieve our mission we adhere to the values of responsibility, honesty, unity, safety and passion for excellence.”
1.2. Objectives and Significance
Minergy is the first independent power producer in the region to sell directly to a private distribution utility. It was established to address the crippling power supply crisis brought by severe draught in Mindanao. Minergy supplies 40% of the energy requirement of Cagayan de Oro. Through MINERGY, CEPALCO was able to provide consistent service to its customer, reducing power outages incidence in its franchise area.

2. Generating Processes
2.1. Description of Generating Processes

Figure 2.1
Figure 2.1 shows a simple diesel engine that is used to generate power in a diesel power plant. First, the fuel is pumped from the fuel storage tank. Then compressed air is sucked into the cylinder. Before maximum compression of the cylinder, fuel is injected. Because of high temperature, the fuel burns rapidly and combustion takes place, initiating the power stroke after which is the exhaust.

Figure 2.2 The engine turns the generator through a shaft coupled to the diesel engine. Then the generator produces the electricity as shown in figure 2.2.

Figure 2.3 Figure 2.3 shows the PV and TS diagram of a limited pressure diesel cycle which best represents the combustion cycle of the diesel power plant.

2.2. Process Flowchart

Figure 2.4 Figure 2.4 shows the process flow chart in a diesel power plant. First is to turn on the fuel pump, oil pump, auxiliary pump and DC source. Then start up the engine at a cranking spend of 500 rpm with a light fuel intake and atmospheric air intake. If the engine started, the fuel intake will be the Bunker C fuel and wait until optimal rpm and temperature is achieved. The process is connected to a cooling water system to lessen the heat in the entire process. Then electricity is generated at 60 Hz and will be transferred to the substation.
2.3. Equipment Flowchart

Figure 2.5 Figure 2.5 shows the equipment flow chart of a conventional diesel power plant. The actual equipment flow chart of the MINERGY diesel power plant is not disclosed in any of its websites. A conventional bunker C diesel power plant is composed of fuel handling system, air intake system, starting system, diesel engine, lubrication system, cooling system, and exhaust system.
2.4. Equipment Specifications

Figure 2.6 Figure 2.6 shows the engine used in the Minergy Diesel Power Plant. Its engines are the Sulzer brand manufactured under the license of new Sulzer Diesel Ltd. by Zgoda of Poland. The three engines used in the power plant are 4 stroke, V12, 6.3MW, 14kVa engines. There are 12 cylinders in one engine. Each cylinder has a capacity of 60.82 L and power capacity of 550 KW. The piston diameter is 400 mm. and its piston stroke is 480 mm. The engine has a nominal speed of 600 rpm. The effective pressure is 18.2 bar and the combustion pressure is 132 bar. The average piston speed is 9.6 m/s. The engine has a nominal speed of 600 rpm and maximum power of 7,260 kW/hr.

Figure 2.7
Figure 2.7 shows the generator used in the Minergy Diesel Power Plant. The generator brand is Ideal Electric from Ohio, USA. The model is Type SAB and has a capacity of 6,300 kW. The voltage is 13,800 V and the speed is 600 rpm.

Figure 2.8
Figure 2.8 shows the MINERGY diesel power plant from the outside. The six chimney-like tubes outside the power plant are the exhaust of the power plant. The silencer has an internal diameter of 2,200 mm, plate thickness of 6 mm, and height of 50,000 mm. The smoke stack has and internal diameter of 904 mm, plate thickness of 6 mm, and height of 17,000 mm. The ducting is 650 mm and has a plate thickness of ¼ inch.
2.5. Operations, Control and Maintenance The following is done for the operations and control of the diesel power plant: * Check jacket water [JW] & injector cooling [IC] water expansion tanks for proper level. * Check inlet & outlet valves of nozzle & jacket water systems for proper open or closed positions. * Press JW & NC water pumps start button located on the engine control panel [ECP]. * Energize JW & IC water heaters by pressing the “ON” button located on the heaters control panel [HCP]. * Set jacket & nozzle cooling water temperature controller to 60°C. * Check level of various engine tanks & auxiliary equipment. * Verify that fuel control linkages & injection pump plunges move freely. * Energize main power supply for engine alarm. * Start up the following and adjust the pressures: * Pre-lubricating oil pump (manual position). * Diesel transfer pump. * Fuel booster module. * Nozzle cooling water pump. * Jacket water pump. * Fuel service pump. * Move each individual fuel pump rack in and out a few times to ensure rack is free and not binding. * Press emergency stop button. * Open starting air valve. * Push starting button for a short period or for at least three (3) revolutions of the crankshaft. * Standard Stopping Procedure can only be carried after a proper unloading sequence of generator with fuel changeover from bunker to diesel fuel oil. * Gradually unload (300 kW/min) the generator to avoid extreme thermal stressing. * Open/trip the generator circuit breaker just before the kW-hr meter reaches 200 kW. * Let generator run for at least 10-15 min to cool down engine. * Set alarm power switch to “DISABLE” position. * Bring down engine speed gradually and press emergency stop button. * Observe automatic start-up of pre-lube pump. * Daily inspection: The plant should be inspected a minimum of three (3) times a day. At least one of the inspections needs to include a thorough check of all systems. * Plant site security. * Exhaust for operating engine. * Fuel level in intermediate tank. * Check control room & switchgear. * Record all data on inspection log. * Record which engine in online & record data. * Inspect offline engines. * Check fuel filter bowl for sediment & water. * Check cooling system. * Check temperature of intermediate fuel tank. * Verify that all lights are working. * Take out trash. * Monthly inspection: Thorough inspection of basic systems in the plant. * Check annunciator lights on switchgear. * Check fluid levels in each cell of battery. * Inspect all fluorescent lights and replace any bulbs that are dim or burned out. * Verify that all emergency lights operate. * Verify proper operation of HVAC equipment & thermostats. * Six month inspection & maintenance * Check filters for air intakes. * Wipe down all light fixtures to remove dirt & oil. * Check automatic air vents installed in the plant & heat recovery piping. * Engine cooling system & heat recovery system must be checked and tested for concentration & corrosion protection. * Annual inspection & maintenance * Fire suppression system needs to be tested and re-certified. * High voltage section of switchgear should be inspected.

The following is done for the maintenance of the diesel engine: * Engine 250 hour service * Take generator offline * Lock unit out * Change engine oil * Clean dust trap on the bottom of air filter * Check water pump for any fluid seeps * Turn unit on and reset service hour to zero * Test unit and verify engine oil pressure * Check oil filter for leaks * Engine 1,000 hour service * Perform all tasks for 250 hour service. * Change fuel filter. * Change glycol filter. * Change crankcase breather filter. * Check air filter. Change if required. * Engine 5,000 hour service * Perform all tasks for the 250 & the 1,000 hour services. * Change air filter. * Adjust valve tappets. * Inspect wiring inside generator enclosure.
3. Productivity Assessment

3.1. Material Balance

Table 3.1
Table 3.1 shows the summary of the material balance for the diesel power plant. The input materials are air, light fuel oil, heavy fuel oil and lube oil. The quantity of light fuel oil and heavy fuel oil is based from the power plant capacity and efficiency which is computed from part 3.3 of the paper. The output materials or products are exhaust gases and deposits, waste water, and sludge from fuel processing. The material balance equation is shown below: (A)C50H102 + (B)(3.77N2 + O2 ) (C)CO2 + (D)H2O + (E)SOx + (F) HC + (G) CO + (H) Nox
3.2. Energy Balance
The total energy sales for the Minergy Diesel Power Plant for the year 2011 is 188 GWh. The average electrical demand of Cagayan de Oro is 18.3 MW. The total diesel engine output: 18.9 MW for the 3 units of diesel engine.
3.3. Efficiencies Computations
To compute for the available power in fuel, the calorific value of heavy fuel oil HFO6 or bunker C fuel of 41 MJ/kg, total power plant capacity of 18.9 MW and diesel engine efficiency of 37% is used.
Required fuel flow (kg/S) [HFO6]: 18.9 MWCV*η=1.2458kgs
Power available in fuel: 1.2458kgs*41MJkg=51.0778 MW A total of 51.0778 MW power available in fuel is computed and will be used to compute the total plant efficiency, along with the actual plant output from the data of year 2011 of 15.61 MW.
Plant efficiency: Actual plant outputPower in fuel=30.56% The computed total plant efficiency is 30.56%.
3.4. Pollutants Generated and Carbon Footprint
The pollutants emitted from the gas stack are particulate and residual matter, sulfur dioxide SO2, Nitrogen Dioxide NO2 and Carbon Monoxide CO. From the waste water, the pollutants are biochemical oxygen demand (BOD), total suspended solids (TSS), Coli form, and sludge.

Table 3.2
Table 3.2 will be used for the computation of the amount of carbon footprint generated in power generation. The energy sales from 2011 of 188 GWh will be multiplied to the emission factor (EF) for the diesel power plant to get the amount of carbon footprint for the year.
Total sales (2011)*EF=Carbon footprint
188 GWh*0.07=13.16 Gg CO2 (2011)
A total of 13.16 Gg of CO2 is generated for the year 2011.
3.5. Safety Record
There is no recorded accident since commissioning date of the power plant.
3.6. Benefits, Costs and Profits
The price of electricity is ₱0.3491/kWh. The average monthly generation cost is ₱23,814,855. The average monthly revenue is ₱59,485,336. The equation for the annual profit is
Annual profit=Annual revenue-12Monthly generation cost The annual revenue is the average monthly revenue multiplied by 12 and the annual generation cost is the average monthly generation cost multiplied by 12. Computing for the annual profit, a total of ₱428,045,775 is achieved.
3.7. Corporate Social Responsibility
The MINERGY has a fire volunteer brigade consisting of 37 personnel and 2 firetrucks tasked to assist in the suppression of destructive fires and/or response voluntarily to other emergencies. They also conduct firefighting training. Pictures are show in figure 3.1.
The MINERGY also donates Isuzu passenger van to the Bomb Squad of Cagayan de Oro police office in response to threats of terrorism in the area.

Figure 3.1
4. Mechanical Engineering Improvement
4.1. Equipment
For the improvement of engine exhaust piping, the exhaust pipes must be fully insulated. The reason is at the end of the power stroke, both the intake and the exhaust stroke are open. The hot exhaust gas creates a vacuum inside the cylinder. Thus, fresh air will rush faster inside. This increases both horsepower and torque helping the combustion process.
4.2. Processes
Excess heat produced can be used to preheat HFO coming from tanks before it is cooled by the cooling tower with the use of regenerators.
4.3. Materials
Thermal barrier coating for the combustion chamber may be used to increase thermal efficiency of internal combustion engines by permitting more complete fuel burning at higher temperatures. The coating is composed of 20% Lead zirconate titanate (PZT) in 60%Cyanate modified epoxy system. This may results in 15.89% reduced specific fuel consumption.
4.4. Issues
Pollution control can be improved by using diesel oxidation catalyst (DOC). The diesel oxidation catalyst is a device that oxidizes exhaust gases, thereby reducing harmful emissions.
CO + ½O2 → CO2 ;[HC] + O2 → CO2 + H2O

5. Benchmarking with an State-of-the-Art Power Plant outside the Philippines

Table 5.1
Table 5.1 shows the summary of benchmarking of MINERGY diesel power plant with the Fuji Electric Co. diesel power plant from Japan. Both powerplants use Bunker C fuel. The Minergy uses three (3) 6.3MW Sulzer12ZV40 engine while the Fuji Electric Co. uses two (2) 10MW G7/G8 engine. The total capacity of Minergy is 18.9MW while the Fuji Electric Co. is 20 MW. The efficiency of the Minergy diesel power plant is 30.56% while the efficiency of Fuji Electric Co. diesel power plant is 36.5%. The diesel power plant of Minergy is turbocharged while the Fuji Electric Co. is turbocharged with intercooling. For the control system, the Minergy uses Vibration Measurement Combustion Control while the Fuji Electric Co. uses M-RICS Combustion Control.
Base from the comparison of the two power plants, it can be said that Minergy diesel power plant is competitive to other state-of the-art power plant of the same type outside the Philippines. Although it can improve more by increasing its efficiency and adding other components such as intercooler.
6. Conclusions and Recommendations
It could be concluded that MINERGY has met its objective of addressing the power supply crisis in northern Mindanao, along with other powerplants in the area.

7. References * http://bpocareerhub.com/company/jobs/mindanao-energy-systems-inc/958 * http://www.cepalco.com.ph/ * http://mechanical-engineering-info.blogspot.com/2011/12/diesel-power-plant.html * http://www.scribd.com/doc/19417287/Diesel-Power-Plants * http://www.mandiesel-greentechnology.com/files/news/filesof6915/KPMG%20Imagestudy.pdf * http://www.elmbridge.gov.uk/envhealth/pollution/pollutants.htm * http://gzwld88.en.made-in-china.com/productimage/sopmxCZMrKhL-2f0j00dvqEobTGhSkR/China-200KVA-Volvo-Generator.htmlhttp://www.mandiesel-greentechnology.com/category_000495.html * http://www.engineeringtoolbox.com/fuel-oil-combustion-values-d_509.html * El Wakil, Power Plant Engineering * http://en.wikipedia.org/wiki/Fuel_oil * http://cpcb.nic.in/Industry-Specific-Standards/Effluent/511-1.pdf * http://www.cepalco.com.ph/readNews.php?id=164 * Kumar, Sundareswaran, The Effect of Thermal Barrier Coatings on Diesel Engine Performance of PZT Loaded Cyanate Modified Epoxy Coated Combustion Chamber , Jordan Journal of Mechanical and Industrial Engineering. * http://business.inquirer.net/75139/2-firms-keen-on-malaya-power-plant-contract * http://www.dal.ca/news/2011/02/14/naturalgas.html * http://www.fujielectric.com/company/tech_archives.pdf * http://www.sunstar.com.ph/cagayan-de-oro/business/2013/08/13/n-mindanao-supplies-6875-energy-q1-297554 * mpmc.minda.gov.ph:32906/.../Mindanao_Power_Grid.pdf‎