Control Method for Direct air capture system integrated with Wind turbine

Abstract

The normal wind turbine employs a tubular or lattice tower to capture air at high speed. It is the speed of air that is important function in the working of a wind turbine. If the air at high speed can also be used to capture the carbon dioxide it will be more energy efficient and economical solution to reduce the carbon emission. The Wind turbine Direct air capture System (WDS) controller is used to control the working of the DAC and make the system efficient to operate at various wind conditions. The WDS controller ensures that the DAC is not operated in low wind conditions where the power exported by the wind turbine is not sufficient to run the DAC system. If operated in such low conditions the DAC might work by taking power from the grid instead of the Wind Turbine.

Specification

Description:The normal wind turbine employs a tubular or lattice tower to capture air at high speed. It is the speed of air that is important function in the working of a wind turbine. If the air at high speed can also be used to capture the carbon dioxide it will be more energy efficient and economical solution to reduce the carbon emission. The Wind turbine Direct air capture System (WDS) controller is used to control the working of the DAC and make the system efficient to operate at various wind conditions. The WDS controller ensures that the DAC is not operated in low wind conditions where the power exported by the wind turbine is not sufficient to run the DAC system. If operated in such low conditions the DAC might work by taking power from the grid instead of the Wind Turbine.

There are basically two ways the carbon emissions that is getting reduced.
1) By producing renewable energy.
2) By direct air capture
Since the land for producing the renewable energy using the wind turbine generator is already available, it can be used to place the equipment of direct air capture system to capture the carbon dioxide at no extra cost. There is no need to have a standalone plant for carrying out direct air capture in this scenario. Also since the Wind turbine is having a considerable amount of height, it will make it more efficient to capture the air at the height of the nacelle of the wind turbine.
The air intake unit(1) which act as the inlet of air can be placed on top of the nacelle (2) as shown in figure 1. The normal height of the wind turbine will be of the range from 80 meters to 140 meters and the tower can be of cylindrical (5) or lattice. At this height the speed of the air would be greater than 3 m/second. Compared to a standalone direct air capture system it will capture air in a more efficient method without the need of large fans and thereby consuming more electricity. The captured air is converted into co2 by using a filter mechanism, the filters(6) are stacked in the different section of the turbine tower (5). The co2 is then converted into liquid inside the filter by heating mechanism and transferred to the reservoir (3) placed near the transformer (4) as shown in the Figure 1.

For a customer it is a win-win situation where the carbon credits are credited for generating the wind energy at the same time carbon dioxide is directly being captured. The captured carbon dioxide can be sold to industries where they can find application for example it can be used in manufacturing cements or in beverage industries. It can also be converted into liquid carbon dioxide and stored under the earth for a long term.

Control Mechanism:
The WDS controller makes sure that the energy used by the DAC is from the Wind Turbine instead of the Grid. This condition is true when the Wind speed is over and above a certain threshold speed.

As shown in above figure 2 the Windspeed from the WTG is taken as input to the WDS controller. The WDS will compare this windspeed with the Threshold speed. The minimum speed for any wind turbine to generate energy is 3 m/sec. The user will be able to specify the threshold voltage which will range from the minimum speed of 3 m/sec to the maximum speed of the Wind turbine operating speed. i.e. 12 m/sec.

Case 1:
If the user has preference to generate electricity in most wind conditions the user may specify higher threshold limits i.e. ranging between 10 to 12 m/sec.

Case 2:
If the user is having the preference to capture more carbon than to export power, the user may specify lower threshold limit i.e. 3 m/sec to 6 m/sec.

Case 3:
If the user wants to run the wind turbine without operating the DAC in any condition then he can choose to disable the DAC using the WDS controller, so the DAC will not be activated in any wind condition. This will ensure the preference for generating energy is given highest priority. This condition may be used when the user has achieved his target for annual carbon capture.

In any case the WDS controller will check the status of the reservoir, if the reservoir is filled by 100% the DAC will get disabled irrespective of any condition mentioned above. The WTG will stop providing energy to the DAC system.

Hardware Interface:

Typical Anemometer uses current output type sensor and measure wind from 0-30 m/sec range. They need to be supplied with external DC voltage of 12-24 volt. They have a power consumption of 0.3 watts and generate output in the range of 4 to 20 mA DC current. For interfacing the Anemometer with the Microcontroller a ADC sensor needs to be used.

The most common type of ADC sensor for measuring the current is a Hall effect sensor. This sensor will take input of 5 volt DC power and can measure the current in the range of 5mA to 30mA. The sensor uses scale factor to convert the measured current to Digital signal.


Current(mA)=(Vout(mV)-2500)/Scale Factor

The measured current can be converted into Wind speed from the current by referring to the datasheet of the sensor.

, C , C , Claims:1. Wind turbine which is used for generating the electricity can used for capturing carbon dioxide and convert it into liquid form.
2. Direct air capture technique for capturing the carbon dioxide can be integrated with the wind turbine generator.
3. Filter mechanism is used to convert the captured air into CO2 and it is stacked in the different sections of the wind turbine tower.
4. WDS controller is used for interfacing the Wind turbine with the DAC.
5. DAC is integrated with the Wind turbine by means of electrical interfacing.

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