2. Kerosene versus Dibutyl Ether
3. Dibutyl Ether Zero Power Generation
5. Drones with Air propeller Propulsion
6. Drones with Air Breathing electric Propulsion
7. Personal Transport – Limitation
8. Load Transport – Limitation
Mobility is a very important property in trade and economy. Additional we have a high personal mobility and a mobility of loads transported from a point A to the next one B in a very short time. Using dimethyl ether as a substitute for fossil diesel in heavy truck has been proven by VOLVO since 2008 [ 4 ]. VOLVO applied dimethyl ether in heavy trucks running on the road over five years showing the benefits of dimethyl ether in the very high reduction of exhaust pollution emission [ 4, 7, 8 ]. But Dimethyl Ether is used in heavy duty trucks running on the road [ 8 ]. Trying to use dimethyl ether in Avionics Cause a lot of problems, therefore we have developed dimethyl ether further to dibutyl ether. Dibutyl ether as a result of the development [ 9 ]has a high application potential in avionics.
2. Kerosene versus Dibutyl Ether
Today one fuel often used in aviation in motors and gas turbines is kerosene fuel [ 6 ]. The properties of common kerosene [ 6 ] are given: ignition temperature 220°C, density 775 up to 820 kg/m³, boiling temperature 75°C up to 250°C, temperature class: T3, heat caloric value Hu= 34 MJ/L ( 800 kg/m³))= 9.5 kWH/L, viscosity n = 8.0 mm²/sec ( T= -20°C ) . Kerosene is a fossil fuel.
Comparing kerosene with dibutyl ether can only be done on the thermodynamic data, because kerosene is often used in Otto engines and in combination with oil in gas turbines. Dibutyl ether is often used in diesel engines and in combination with additives in gas turbines.
The properties of common dibutyl ether [ 7, 9 ]are given: ignition temperature 250°C, density 775 up to 820 kg/m³, boiling temperature 140°C up to 250°C, temperature class: T3, heat caloric value Hu= 43 MJ/L (800 kg/m³)) = 10.5 kWh/L, viscosity n = 8.0 mm²/sec ( T= -20°C ). Dibutyl ether is a renewable organic fuel. [ 9 ]
Comparing the main thermodynamic properties between both fuels we see that both fuels have nearly the same properties, and the possibility is given to substitute kerosene with dibutyl ether as fuel for gas turbines.
3. Dibutyl Ether Zero Power Generation
The pathway to dibutyl ether is running over the production of dimethyl ether. Dimethyl Ether is produced from synthetic gas, carbon monoxide (CO) and hydrogen (H2), or carbon dioxide and hydrogen (H2) with a catalyst under low pressure (pressure range p = 30 bar up to 100 bar) at a temperature of T = 200°C up to 300°C. In most cases dimethyl ether is produced over the intermediate product methanol (CH3OH), and the Dehydration of methanol to dimethyl ether. [ 8 ]
Chemical reactions for the pathway over carbon monoxide and hydrogen:
Abbildung in dieser Leseprobe nicht enthalten [E 1 ]
Chemical reactions for the pathway over carbon dioxide and hydrogen:
Abbildung in dieser Leseprobe nicht enthalten [E 2]
With Dimethyl ether using hydrogenation and carbonylation supported by catalysts Dimethyl ether is converted to methanol and ethanol. Methanol is recycled and ethanol is used to be converted to butanol over a catalyst. Butanol is reduced by dehydration supported by a catalyst to dibutyl ether. The chemical reactions are listed up:
Abbildung in dieser Leseprobe nicht enthalten [E 3]
Dibutyl ether can be stored in a tank at environment pressure. The evaporation temperature is given with a temperature T ~ 150°C. Dibutyl ether as a fuel can be converted to electric energy and thermal heat with the following process: The fuel dibutyl ether is heated up and filled in the combustion swing chamber. In the combustion chamber dibutyl ether is converted with oxygen to carbon dioxide (CO2) and hydrogen(H2):
Abbildung in dieser Leseprobe nicht enthalten [E 4]
The hot exhaust gas has a temperature of 1600°C up to 2000°C. The highly exergetic heat is converted with a closed magneto hydrodynamic (MHD) generator system to electricity and heat. In the application the number of MHD-generators is at least one and maximum four. The liquid carbon dioxide (CO2) and water (H2O) are stored in tanks. The operating pressure of the exhaust system is about p = 70 bar. Water steam condensation takes place at a temperature of T=263°C and carbon dioxide condensation takes place at a temperature of 25°C. [ 1, 2, 3 ]
Figure 1: Zero Emission dibutyl ether with Plasma Generator based on the MHD technology, storing carbon dioxide and water in liquid phase in tanks. (Source: Johann Gruber-Schmidt, 2018)
In the figure  a simple power cycle based on dibutyl ether is shown. The fuel dibutyl ether is led into a swing combustion chamber, in which the fuel with oxygen is oxidized to carbon dioxide and steam. The hot exhaust has temperature between T=1600°C up to T=2000°C. If we have an operating pressure p~ 70 bar, steam condensing can be realized at a temperature T~ 260°C. At a pressure of p~ 70 bar carbon dioxide condensing takes place at a temperature T~ 25°C.
The heat is converted in a small closed magnetohydrodynamic cycle. The generator is operating based on the Hall effect. The cascade of several MHD generators enable to increase the electric efficiency. The generator produces electric power under constant voltage. (DC). The power module includes also a battery system, to stabilize the controlling and measurement system. The electric power is used for electric power driving motors.
The condensed water is collected in a tank, the condensed carbon dioxide is collected in pressurized tanks ( p~ 70 bar ).
The oxygen for oxidation of dibutyl ether is take from the air. The air is preheated and led into the combustion reactor. Using two reactors lead to a combustion swing system is so very close to the continuous process.
One application of the Zero Emission Fuel is to use dibutyl ether as a fuel for drones. Drones are well-known and the next step is to enlarge the drones for passenger transportation and container transportation. The drone is an element of the three-dimensional space and enlarges the mobility from the plane (surface) up to the near surface earth space. This is a necessary step to increase the mobility in transportation and to stop wasting time, if the cars and truck are waiting in an unexpected traffic hold up. [ 13 ]
Drones have the advantage to act individual and free, so the flexibility of transportation and mobility is increased dramatically. Inside the drone, the passenger can watch and check the transportation, if necessary they can start emergency operation.
The propulsion for drones in this short article is analyzed to be done by propeller propulsion or electric plasma propulsion [ 11 ]. The thrust F[N] for a drone must be greater equal the own weight and the load to lift off, the thrust T[N] for moving forward is defined by travelling velocity uT [m/sec]
Abbildung in dieser Leseprobe nicht enthalten [E 5]
The equation shows the equilibrium of the weight F[N] including the mass of the drone and the load and the thrust from the propulsion engines. The velocities of the flowing air mass (mAir) are the entrance velocity in the propulsion engine and the exhaust air velocity u1. For the travelling velocity uT, we have the equilibrium force T[N]. The lifting of the drone and the travelling velocity of the drone are weak coupled.
- Arbeit zitieren
- Dr. techn. Johann Gruber-Schmidt (Autor), 2018, Dibutyl Ether as Fuel in Aviation Drones, München, GRIN Verlag, https://www.grin.com/document/435052