There are modern turbine systems that are of high efficiency, fuel-flexible, have low emission, and great for power generation but it can be confusing choosing the right one. Well, if you are looking out for a turbine for power generation, then you should be looking at trying out gas turbine but before then, you should read a comprehensive review on the gas turbine to get more insight.
Overview of Gas Turbine
The gas turbine which is otherwise known as a combustion turbine is a combustion engine that can convert liquid fuels or natural gas to mechanical energy. This energy will then be used to drives a generator that will produce electrical energy to power appliances, equipment, and tools. The gas turbine can be said to be the engine at the heart of a power plant that releases electric current. The elements that are common to gas turbines are combustor, an upstream rotating gas compressor, and a downstream turbine on the same shaft as the compressor.
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What is a Gas Generator in Gas Turbines?
As earlier stated every gas turbine has three elements which are the compressor (red), combustion (cyan), and the turbine (magenta). These three elements can be called the core of the gas turbine engine and all gas turbines have these three elements. These cores can be described as the gas generator since the output of the core is hot exhaust gas.
Features of Gas Turbine
- The gas turbine produces power using acceptable electrical efficiency.
- With gas turbine emission is low and it has high reliability.
- The gas turbine has three main sections (power turbine, combustor, and compressor) to aid in its operation.
- It helps to mix air and fuel to convert chemical energy to heat.
- The gas turbine has a high exhaust gas temperature and amount.
- It has an electrical efficiency that is about 29% -33%
- Vibration rate or level is ultra-low.
- The machine size is small
- It takes a very long time before maintenance i.e. maintenance interval is long
- The start-up time is very low.
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How Does Gas Generator Produces Electricity
Generating electricity with gas turbines involves the gas turbine heating a mixture of air and fuel at a very high temperature this causes the turbine blades to begin spinning. When the turbine start spinning it will drive a generator to convert the energy produced into electricity. To create power that is extremely efficient that the gas turbine can be used with a steam turbine. The following steps are involved in power generation
- Step 1: Gas turbine compresses air and mixes it with fuel creating a hot gas
- Step 2: The hot air moves via blades in the turbine making them spin very fast
- Step 3: The spinning of the blade turn the driveshaft
- Step 4: The spinning turbine is connected to the rod in a generator; the turbine rotation powers the generator
- Step 5: The fast revolving generator causes the electrons to move and this creates electricity
How Does a Gas Turbine Start?
Starting a gas turbine has to do with an electric motor spinning the main shaft till there is enough air blowing through the compressor and the combustion chamber to light the engine. From here fuel will start flowing and the igniter which is almost like a spark plug will ignite the fuel. Thereby making the gas turbine to start.
Types of Gas Turbine
There are 4 types of gas turbines, they are as follows:
- Types of duty
- Combustor types
- Shaft configuration
- Degree of packaging
Types of Duty
Gas turbines can be classified by the type of duty it can be performed e.g of these gas turbines are Aircraft turbine engines, heavy industrial gas turbine engines, and light industrial gas turbine engines.
Gas turbines can be designed according to its combustor type’s e.g. radial or annular combustor and can combustor.
This gas turbine type can be classified according to its shaft configuration. The gas turbine can either be a single shaft or two-shaft design. So each gas turbine comes in any of the earlier written shafts. E.g. single shaft or two shafts.
Degree of Packaging
The gas turbine can be classified according to its degree of packaging like having start systems, fuel systems, local controls, lubrication system, and the gearbox.
Gas Turbine Components
The gas turbine has 3 main component units. They are: the compressor, the combustor, and the turbine.
The component that offers the compression part of the gas turbine engine thermodynamic cycle is the gas turbine engine compressor. The compressor helps to draw more pressurized air into the combustion section and a generator is spin to produce electricity.
The combustor otherwise known as the burner is an area of a gas turbine where combustion takes place. In the gas turbines, the combustor is fed high-pressure air via the compression system, the combustor will then be heating the air at constant pressure and when the heating is over, the air will pass from the combustor via the nozzle guide vanes to the turbine. The combustor is responsible for other engine’s operating features like the levels of emissions, fuel efficiency, and changing conditions such as the airspeed and fuel flow.
The Power Turbine
This is the part of a gas turbine that transfers enthalpy of exhaust gas into kinetic energy. This energy produce by a power turbine is used for generating electrical power when used with a generator. This component also helps to produce the power that drives air compressor and the output shaft.
How Much Does Gas Turbine Cost?
When it comes to power generation with gas turbines and its installation, from our research, new turbines are within the range of $700 – $5000 depending on their sizes but for the installation cost it is approximately $270 per KW.
What Are the Applications of Gas Turbines?
Gas turbines can be used or applied in various ways; one is being used as a medium-sized peak load plant to run intermittently during a short period of high power demand on an electric system. Again, it can also be applied as driving compressors for pumping natural gas via pipelines; in this case, the small part of the pumped gas will serve as the fuel.
Which Fuel is Used in a Gas Turbine?
The gas turbine has the flexibility of fuel because it can be used with diverse light distillate petroleum products or flammable natural gas products like gasoline, paraffin (kerosene), diesel, or patrol. Any locally available natural gas can be used as fuel for a gas turbine.
Advantages and Disadvantages of Gas Turbine
Gas turbine generator has pros and con, pros is more comparing to the con. The advantages and disadvantages of gas turbine as follows:
Advantages of Gas Turbine
These are pros of gas turbine gas over other types of turbine
- It has fast started and loading up
- It has relatively fewer auxiliaries than the steam turbine
- The gas turbine has a low capital cost
- With a gas turbine, a little cooling system is required
- No vacuum is needed anywhere with gas turbine
- The gas turbine has simple speed control which is mostly for air and fuel
- Fuel efficiency at high power
- The gas turbine doesn’t need specialized fuel for use.
- It has low operating pressures but with high operation speeds.
Disadvantages of Gas Turbine
The cons of gas turbine include:
- The gas turbine has limited efficient rpm range
- Gas turbines are expensive to manufacture
- It is slow to respond to acceleration when on low speed
- It has a high noise level
- High running cost both its price and fuel type
- The gas turbine needs huge amounts of air with vast high-temperature exhaust gas flow
What is Gas Turbine Efficiency?
Gas turbine efficiency is the ratio of actual work output of the turbine to the net input energy supplied in the form of fuel. Now, since wear out gas from the gas turbine is high, it is possible to recover energy from the hot gas by a heat recovery steam generator and use the steam for process.
Why Gas Turbine Efficiency so Low?
A gas turbine that stand-alone without any heat recovery system will always be low inefficiency; it can go low between 35%-40%. This low efficiency is attributed to leakage through clearance spaces, blade efficiency of the rotor, irreversible turbulence, friction, and lots more.
How can we Increase the Efficiency of Gas Turbine?
Gas turbine efficiency can be improved and increase by cooling the inlet air. This is especially effective in hot, dry climates. A significant benefit of turbine air inlet cooling is that it can reduce (or eliminate) fuel efficiency reduction by evaporative cooling the inlet air to the wet bulb temperature.
What is the Working Principle of a Gas Turbine?
The gas turbine works with the principle of the Brayton cycle. This simply means that compressed air will mix with fuel and it will burn under constant pressure conditions, then the resulting hot gas will be allowed to expand via a turbine to perform available work.
What is Difference Between a Steam Turbine and Gas Turbine?
Gas turbines rotate directly in hot combustion gases. Its temperatures are always up to 1500Celcius. With this temperature the gases are normally hotter than the gases found in steam turbines, Afterwards, the blades are cooled with the air that flows out of small openings and a protective film is created between the blades and exhaust gases.
Now without cooling, the blade material in use would swiftly wear out. On the other hand, steam turbines rotate in the currents which are caused by hot water vapors. These steam turbines form part of a closed water cycle that water condenses and it is then heated till it evaporates again. So with this, steam turbines don’t come into contact with fuel used and only work at temperatures which might be between 500-650Celcius. Various steam turbines are usually arranged in a row so that it is configured into low, medium and high pressure. With this arrangement, they can optimally convert these different levels of steam pressure into rotational movement.
Where Are Gas Turbine Engines Used?
Gas turbine is used in different applications in respect with their sizes, typically a gas-turbine ranging from 1,000 to 50,000 are used in horsepower area, also industrial gas-turbine engines can be used for many applications alongside driving compressors for pumping natural gas through pipelines, where a small part of the pumped gas serves as the fuel.
As the power generation is growing, the mean of getting good power sources is been improved which gas turbine happens to be among this growth. Following the power generation, the gas-turbine or combustion turbine converts liquid fuels or natural gas to mechanical energy to drives a generator that will produce electrical energy to power appliances, equipment, and tools. Purchase one today to enjoy the growth and development in the power generation industry.