https://journal.gpp.or.id/index.php/ijrvocas/index
43
The Application of Vacuum Valve Technology as AFR Settings in 3500 Watt Electric Generator Operated by Methane Gas
Tri Widagdo
1, *, Eka Satria Martomi
1, Ella Sundari
1, Selastia Yuliati
21Department Mechanical Engineering, Politeknik Negeri Sriwijaya, Palembang, Indonesia
2Department Chemical Engineering, Politeknik Negeri Sriwijaya, Palembang, Indonesia
Email address:
*Corresponding author
To cite this article:
Widagdo, T., Martomi, E. S., Sundari, E. ., & Yuliati, S. . (2022). The Application of Vacuum Valve Technology as AFR Settings in 3500 Watt Electric Generator Operated by Methane Gas. International Journal of Research in Vocational Studies (IJRVOCAS), 2(1), 43β49.
https://doi.org/10.53893/ijrvocas.v2i1.97
Received: March 03, 2022; Accepted: April 05, 2022; Published: April 25, 2022
Abstract:
The scarcity of fuel oil, especially the gasoline type, is now a national problem that needs to be solved. This is caused by the rapid growth of industry and transportation. On the other hand, the problem of handling wet garbage has not been maximal, causing pollution that can disrupt health. The impact of this problem is felt also in the use of household-scale generators that operate using gasoline fuel. This study aims to convert gasoline to methane gas in the operation of a 3500 Watt Generator (Electric Generator Set). Methane gas (CH4) is obtained from the gasification process of wet waste. The method used for the AFR (Air-Fuel Ratio) regulator is the use of vacuum valve components. The use of this method cannot be separated from the easy aspects of the maintenance/repair, easy to make and cheap price. The target to be achieved in this research is to get performance data of generators operated with Methane gas fuel. The generator which is used as a research object is a generator household scale with a maximum power of 3500 Watt. Results variables to be observed among other: engine efficiency as well as optimum engine AFR generator. Furthermore, the data is compared with the data generated generator that uses gasoline fuel.This research is an experimental study, starting with the design of the vacuum valve component, followed by the installation of the component on the generator machine and ending with a machine test. The experimental data on the generator with the nominal power of 3500 Watt is: Operated by Gasoline, the optimum power, Popt is 3750 Watt, Max. efficiency, Ξ·max is 62.2%; AFRopt is 6.7, then operated by methane gas, optimum. power, Popt is 3270 Watt, Max efficiency, Ξ·max is 66,1%, AFRopt is 7,2. So, gas methane can be used to replace gasoline to operate 3500 Watt generator.
Keywords: methane, AFR, vacuum, valve
1. Introduction
Mineral fuel reserves, which include petroleum (BBM), natural gas and coal, are increasingly becoming thinner. The fuel has long been recognized by the world as an easy-to- obtain heat source and is easy to use in heat-mechanical energy conversion machines, such as Diesel engines, gasoline motors, gas turbines and steam power systems ect. On the other hand, the industrial need for heat energy sources that can be converted into mechanical energy is increasing. The impact of
this phenomenon is: soon the mineral fuel will be exhausted.
Some solutions that have been developed include the utilization of natural energy (waterfalls, geothermal, wind and sunlight). However, it is still not fully socialized because it still encounters several problems, among others: the initial cost is expensive, less practical and not constant because it depends on climate and / or weather. Meanwhile, the use of nuclear energy is also not fully accepted by the public, due to radiation
hazards as the nuclear bomb that occurred in Hiroshima in 1945 ago. Statistical data for energy consumption in Indonesia for the last 15 years, in Giga Joule (GJ) can be seen in the following table.
Tabel 2. Energy Consumption in Indonesia[1]
Type of Usage Years 1995-2000
Years 2000-2005
Years 2005-2010 Industry 178 x 106 GJ
(45 %)
193 x 106 GJ (47 %)
215 x 106 GJ (46 %)
Transportation 124 x 106 GJ (37 %)
131 x 106 GJ (38 %)
139 x 106 GJ (38 %)
Household 78 x 106 GJ (18%)
82 x 106 GJ (15 %)
88 x 106 GJ (16 %) Total 380 x 106 GJ 406 x 106 GJ 442 x 106 GJ
On the other hand, the world's mineral reserves, if explored indefinitely, will be exhausted within 65 years (for fuel) and 150 years (coal). The use of other natural energy, such as sunlight, wind and waterfalls, is still constrained on continuity and expensive.
The methane (CH4) gas to be used to replace the gasoline fuel has similarly thermodynamic properties, so it is probable that Methane gas can replace the gasoline as fuel, especially for a 4-stroke motor fuel type.
Table 2. Gasoline and Methane properties [1]
Properties Gasoline Methane gas (CH4)
Information
Phase Liquid Gas At standard
condition Flamming
point
780C 720C At 1 atm
pressure
LCV 46,7 MJ/kg 55,5 MJ/kg
HCV 42,5 MJ/kg 50,1 MJ/kg
Flamming speed
0,043 mili sec/gram
0,054 mili sec//gram
Batch system
Waste material
0.0043/gram/kg fuel
0,0022 gram/kg fuel
Form of crust
Generator (Electric Generator Set) is meant in this research is a machine that convert the energy of heat of ignition into mechanical energy and back into electric energy.
Figure 1. Energy balance of generator
The overall efficiency is calculated using the formula:
ππ=πΈππππ‘πππππ ππππππ¦
πΆππππ πΈπππππ¦ π₯ 100% = π.πΌ
πΜ.πΏπ»ππ₯ 100% (1) where: V : Electrical voltage, Volt
I : Intensity (current), Ampere πΜ: fuel mass flow rate, kg/se LHV: Lower Heating Value, J/kg
Generator commonly used in the community has a range of electrical power between 1500 Watt to 7000 Watt, driven by the engine of the type piston motor fuel with gasoline fuel.
The alternator is connected directly to the engine, so they both have the same rotation. Alternator works as an AC power generator which produces 50 Hz electric frequencies. For that engine must be able to rotate at optimum rotation [7]:
n = (120 f) / P (2) where, f: Electrical frequency
= 50 Hz
P: number of poles = 2
(for household-scale generator)
So the optimum engine speed is 3000 rpm. To stabilize the rotation, the engine is equipped with a Mechanical Speed Governor, principle to control the opening of the gas on the carburetor. Household-scale generators are usually operated if electricity from the PLN network has been shut down. State of the art of this research is the use of LPG fuel to operate household-scale generator. The scarcity of premium fuel is not an obstacle to operating the generator. Generator in this research using engine type piston motor (internal combustion engine) 4 step bias use fuel of premium (gasoline). Generator that has been modified, then can be Hybrid [4-8], meaning can be operated by both gasoline and methane gas.
Some similar research that the author has done and published through scientific journals, among others
1. Jatropha oil biodiesel production through Transesterification process, Competitive Grant research, published through Jurnal TEKNIKA Polsri, 2001 In conclusion: Jatropha Oil can be used as a replacement fuel for diesel engines that usually use diesel fuel type.
2. 'Design of Stirling Machine of type Ξ² using which is operated using Biomass fuel' BOPTN research, published through AUSTENIT Journal, 2005
In conclusion: Ξ²-type Strilling Machine can be operated with some biomass fuel, like methane gas from wet waste fermentation, and wood burning from sawdust.
3. 'The design of Centrifugal Governor as the regulator of the son on Motor Bakar Torak', Research fund DIPA 2001, published through Jurnalak TEKNIK 5th edition Vol 2
In the conclusion: Motor Fuel Torak 1 cylinder 4 steps, can be arranged by using centrifugal in rotation 2500 rpm with tolerance Β± 25 rpm.
Converting gasoline to methane gas fuel used Vacuum valve component which will be designed in the form of small tube and must be able to change the pressure inside the tube to be smaller than the pressure on the methane tube so it can suck and run the gas to carburetor through the hose media. This tool is called a vacuum valve. The process that occurs in methane gas fueled generators can be seen in figure 2.
Figure 2. Experiment lay out to fuel conversion gasoline-methane gas
Process 1-2:
The process by which the engine rotates will produce air suction which is flowed by the carburetor valve so that it sucks the rubber inside the vacuum valve and functions it as a membrane to continuously suck Methane.
Process 2-3:
Methane gas sucking process conducted by vacuum valve and fed to the carburetor.
Process 3-4:
The process by which Methane gas is atomized but with different ratios compared to gasoline.
Process 4-5:
The process by which fuel is compressed by the piston and in the presence of spark plugs that serve to spark the sparks, there will be a combustion process that will produce a torque that rotates the crankshaft.
Process 5-6:
The process by which torque on the crankshaft is used to rotate the generator to produce AC power.
Process 6-7:
The process of distributing AC electrical power for use through terminals
Vacuum valvet is a series of some components that have been modified in such a way that it can produce a fuel distribution system in this case in the form of gas Methane to be able to replace the previous fuel that is gasoline. The components of the fuel versions consist of vacuum valve, modified carburetor, and modified insulator.
The following figure presents the systematic Vacuum valve as a major component in the conversion of gasoline fuel to Methane gas in this study.
Vacuum valve has a vital function in our design, in simple vacuum valve serves as a tool that can change the pressure to be smaller than the pressure in the Methane gas tube so as to
such the gas in it, which is then flowing kekarburator (Figure 3).
Vacuum valve consists of several components, namely:
β’ Membranes made of thin and elastic composite material.
β’ Membrane holder made of copper.
β’ Copper pipes.
β’ Membrane retaining spring.
β’ Housing up and down as a home made of carbon steel
Figure 3. Vacuum valve construction
Vacuum valve Principles:
1. When the membrane is pulled sucked down, the valve above the membrane opens and opens the gas line. This causes the pressure inside the vacuum valve to shrink so that the gas inside the Methane gas cylinder will be inhaled.
2. When the membrane returns to its original position, the valve closes the gas line so that the gas which has been inhaled and located inside the vacuum valve will be supplied to the carburetor through the pipe channel.
3. The process that causes the membrane pulled down and back to the starting position is because at the time of the motor at start, the crankshaft will rotate the crank shaft on the piston so that the piston inside the cylinder will perform suction step,
4. In suction step will produce strong suction power. This is utilized to pull the membrane and open the membrane valve through a copper pipe medium mounted on the insulator. At the same time the stepping down of the membranes has decreased with gas.
5. After the suction step, the piston will perform a compression step which causes the piston to be pushed upward inside the cylinder, so that the membrane returns to the starting position and the valve closes the gas line.
This research is a continuation of previous research [6-9], which has the object of research type Stirling Machine and operated with fuel methane gas. Specific objectives to be achieved from this research are to get the Implication Correlation of Research Variables on the operation of generator using methane fuel. The research variables that are directly related to engine performance are engine power, optimum rotation, efficiency and engine specific power. While other variables that are not related directly to the performance of the engine include: vibration, noise and pollutants resulting
2. Vacuum Valve
1.Mehane gas
4. Modified carburetor
1. Carburetor valve
5. Engine 6. Electric Generator
7. Output
From Methane gas reservoar To carburetor rear intake
Membrane clamp
Membrane
Needle valve jarum
To carburaetor front intake Regulating spring
Fastener bold
from the combustion process of the engine. The prototype vacuum valve will be piloted to operate on a household scale generator with a maximum power of 3500 Watt [10-11].
Urgency (research) lies in the utilization of heat energy (heat) generated from the combustion of methane gas, which so far only cause pollution of odor in landfill (TPA) waste.
Generator scale household machines that stout on the market all still operate by using premium fuel. Some problems encountered by users are the difficulty of getting premium fuel, because all gas stations refuse to sell premium to buyers who use jerry cans. On the other hand, without realizing that the use of premium fuel for stationary motor fuel produces many pollutants, especially CO (Carbon Monoxide) which is very harmful to health. Converting premium fuel to methane gas is a technological innovation that is very beneficial for the user community of generators. The following shows the annual plan in accordance with the targeted outcome and the length of the study.
2. Research Methods
This research is a continuation of previous research [5], which discusses the processing of biomass into renewable fuel.
This research is Inductive, that is taking direct data from real event in field. The method used is Kaji Ekaperimental to a natural phenomenon by involving some research variables that have been determined. In general, research activities are divided into six main activities, namely:
2.1. Procurement of Generator Test
One-unit generator which will be used as research object and will be driven by gasoline motor with maximum power 3500 watt, operate at 3000 rpm rotation. The electricity produced is a type of AC with a nominal voltage of 220 Volts
.
2.2. Procurement of Measurement Instrument a. Tachometer, serves to measure the engine speed b. Multi tester, serves to measure the voltage and electric
current generated by the alternator.
c. Anemometer, serves to measure the speed of air flowing into the intake manifold engine.
d. Gas identifier, serves to determine the composition of exhaust gas burning results.
e. Potentiometer, serves to provide alternator load when the generator is operated using gasoline or methane gas.
2.3. Design Vacuum Valve
Generator testing is done for two types of fuel. Each test is done with a duration of one hour. The main variable of testing is the alternator load, in the form of an electric current that is supplied to a potentiometer. Variation is done by setting the impedance value potentiometer. The load setting is limited along the alternator while still generating a voltage of 220 Volts. The involvement of research members is very influential on the targets to be achieved. For that matter, discussion and
consolidation will always be implemented periodically. The competencies of each member are deemed sufficient in accordance with the workload they will finish.
3. Results and Discussion
3.1. Research Results 3.1.1 Device design testing
Research data retrieval begins with the procurement of methane gas. Methane gas is obtained from chemicals.
Furthermore, gas is checked for its purity using GC (Gas Chromatograph) [11-13]. The result of the examination is obtained quantitative data showing purity level on mass basis about 94%. Other components that conjugate are Nitrogen gas as well as some light hydrocarbon gas as 6%. Further gas is accommodated on a tube with pressure of 200 bar. For use, the gas pressure is reduced to about 0.8 bar (11.8 psi). This value is obtained based on the conditions membrane on vacuum valve.
The mass flow rate of methane gas to the engine is read using a flow meter. Calculated thermodynamically based on measurable temperature and pressure.
Figure 4. Methane gas measurement instruments
To turn the gas engine methane flowed into the vacuum valve and accommodated in the upper room of the membrane.
If the engine is in a stop state of operation, the methane gas cannot flow. The new methane gas can flow if there is control from the engine intake manifold which pulls the membrane to open the gas valve, then the methane gas will flow through the front manifold. AFR (Air-fuel Ratio) is calibrated using existing springs in the vacuum valve. Electrical loading of the generator is done by using a wet element made of satin steel plate.
Figure 5. Vacuum valve
Operation of engine using premium fuel is done in accordance with standard device of engine, while in operation of engine use gas methane, then added component vacuum valve which function as AFR regulator.
4.1.2 Experimental procedure
The procedure for retrieval of operating data of generator using Premium fuel is as follows
a. Unlock the gasoline fuel valve and deliver it to the carburetor.
b. Turn on the engine using electric starter.
c. The initial operation of the generator is about 1 minute for the purpose of initial packing until the condition is stable.
d. Provide initial load generator with current about 1.5 Ampere for generator.
e. If the code is stable, then other main data is recorded, other: premium discharge to the engine, generic voltage generator and generator frequency. Additional data that is also observed is the generator response when receiving electrical loads.
f. Steps 4 and 5 are treated for larger electrical loads.
g. The procedure for collecting operational data on Generator's operation using methane gas fuel is as follows.
h. Unlock the main valve of the methane gas cylinder.
i. Lowering the gas pressure to a value of about 0.8 bar.
j. Turn on the engine using electric starter.
k. Initial operation of generator about 1 minute for the purpose of initial trimming until stable condition.
l. Provide initial load generator with current about 1.5 Ampere.
m. If the codes are stable, other main data are recorded, other:
methane gas discharge to the engine, generic generator voltage and generator frequency. Additional data that is also observed is the generator response when receiving electrical charge.
n. Steps 5 and 6 are treated for larger electrical loads.
Data test result data can be seen in the following table
Table 3. Experimental data from generator operated by gasoline
Load No.
Elec.
Voltage, V (Volt)
Elec.
intensity, I
Fuel mass flow rate,πΜπ,
Elec.
Frequency, F(Hertz)
Generator
& engine response
(Ampere) kg/sec
1 220 5,6 0,0000725 54,4 Normal
2 220 10,7 0,0000994 54,1 Normal
3 210 17,5 0,0001387 51,8 Vibration
increase
4 195 19,8 0,0001508 48,6 Vibration
increase,
5 184 22,4 0,0001651 46,4 Overheated
Table 4. Experimental data for Generator operated by Methane gas Load
No
Elec.
Voltag, V (Volt)
Elec.
intensity, I (Ampere)
Fuel mass flow rate,πΜπ,
kg/sec
Elec.
Frequency, F(Hertz)
Generator
& engine response
1 220 12,2 0,0000119 52,2 Normal
2 220 14,3 0,0000994 52,1 Normal
3 220 16,2 0,0001387 50,6 Normal
4 210 17,9 0,0001508 49,4 Vibration
increase
5 200 19,1 0,0001651 48,8 Overload
4.2. Discussion
Test data from the table 3 and 4 have been tested for significance using Chi-test statistical test, then do recapitulation with the needs of data analysis to be implemented. It can be seen in table 5.
Operated with Gasoline Operated with Methane gas Electrical
power, P, Watt
Efficiency , Ξ·o, % Electrical power, P, Watt
Efficiency , Ξ·o, %
1245 40,4 2678 44,8
2350 55,6 3145 63,7
3677 62,4 3564 65,6
3876 60,8 3766 58,8
4126 58,8 3809 55,3
The trend line approach as a quadratic function (by 2nd order polynomial) generated correlation data:
a. Operation of generator with gasoline fuel (figure 6), - trend function, y = -4e-06 x2 + 0.03 x + 9,276 - Regression coefficient, R2 = 0.993by With the first derivative method obtained:
- Optimum power generator P = 3750 Watt - Maximum efficiency of generator, Ξ·max = 62.2%
Figure 6. Characteristic curve of generator operated by gasoline
Figure 7. Characteristic curve of Generator operated by methane gas
b. Operation of generator with Methane gas (figure 7), - Function of trend (function trend), y = -5e-05 x2 + 0,327
x + 482,3
- Regression coefficient, R2 = 0.986 With the first derivative method obtained:
- Optimum power generator P = 3270 Watt
- Maximum efficiency of generator, Ξ·maks = 66,1%
Figure 8. Characteristic curve generator from experiment
The performance of gas methane is better than gasoline. It can be seen in figure 8. The efficiency maximum is 66.1%
while gasoline 62.2%.
4. Conclusion
From what has been done in this study, it can be concluded that methane gas has better performance compared to gasoline.
The optimum power of generator is 3270 Watt, and the maximum efficiency of generator is 66.1 %. So, gas methane can be recommended to replace of gasoline for the running generator.
References
[1] ... ESDM (2011), 'Statistics of Fuel Consumption in Indonesia, Ministry of Energy and Mineral Resources of the Republic of Indonesia
[2] Kent's (2010), Mechnical Engineering Handbook, Power Volume, 4th edition, Toppan Company, Tokyo
[3] Maleev V I (2009) Internal Combustion Engines, International Student Edition, 17th printing, Mc-Graw Hill Book Company, London.
[4] Winardi B. and Nugroho A. 2022, Study of Generator Set Overload Protection System in Power Generation Units, International Journal of Research in Vocational Studies (IJRVOCAS) Vol. 1, No. 4, January 2022, pp. 11~1., DOI:
https://doi.org/10.53893/ijrvocas.v1i3.58
[5] Azharuddin, Arnoldi D., Putri F., Almakky K. M. F., Davala M.
Ivan., 2021, Study Analysis Fuel from Plastic Waste, International Journal of Research in Vocational Studies (IJRVOCAS) Vol. 1, No. 3, December 2021, pp. 08~16., DOI:
https://doi.org/10.53893/ijrvocas.v1i3.59
[6] Sailon and Widagdo T (2008), Mechanical Dynamometer with Round Governoor Centrifugal, Research Report of DP2M Young Lecturer.
[7] Widagdo T and Cholik M (2002), title: Dynamic Character Machine Stirling., Scientific article, Journal of Mechanical Engineering, ITB.
[8] Widagdo T (2009), 'Stirling Machine as Solution to Overcome Fuel Oil Scarcity', Tuisan Ilmiah field of technology, published in Daily Sumatera Ekspress August 12, 2009.
[9] Widagdo, T (2004) Making Jatropha Curcas Biodiesel using Transesetrification Method. Proceedings of Seminar on Competitive Grant Report 2004/2005.
[10] Zuhal, T and Amran S (2009), Fundamentals of Electricity, Theory and Applications, Issue 4, Publisher ITB, Bandung [11] ... http / www / engine. ectcomb. Go.id/: 'Stirling Engine,
free encyclopedia International
[12] Zulatama A., Syarif A., Yerizam M. (2021). Effect of Oxygen Flow Rate on Combustion Time and Temperature of Underground Coal Gasification, International Journal of Research in Vocational Studies (IJRVOCAS) Vol. 1, No. 2,
August 2021, pp. 27~33, DOI:
https://doi.org/10.53893/ijrvocas.v1i2.27.
Gasification (UCG) Testing of In-SituType Lignite Coal and
Fracture Type Coal, International Journal of Research in 67~78, DOI: https://doi.org/10.53893/ijrvocas.v1i2.42
