1. Seed metering device for a row crop sowing machines, also called seed planters, comprising
a seed metering disc rotatable about a central shaft, having a plurality of seed capturing and retaining means for capturing and retaining the seeds,
a motor, which drives the seed metering disc,
releasing means for releasing the seeds from the seed capturing and retaining means,
conducting means for conducting the released seeds onto the ground, and
a housing for containing and protecting the metering disc,
wherein the motor is of the hollow-shaft type, toroidally shaped and coaxially coupled to the metering disc.
2. A metering device according to claim 1, wherein the hollow-shaft motor is a direct drive DC motor of the brushless type.
3. A metering device according to claim 1, wherein the seed capturing and retaining means are selected from the group comprising holes, cells or cradles located near the outer perimeter of the metering disc.
4. A metering device according to claim 1, wherein the seed capturing and retaining means consist of holes located near the outer perimeter of the metering disc and the hole size is determined by the type of seed to be sown, so as to be able to retain the seeds in place until reaching the releasing means.
5. A metering device according to claim 1, wherein the metering disc is a cogwheel or gear, the teeth of which are the seed capturing and retaining means, where the teeth shape and the size of the gap between the teeth being determined by the type of seed to be sown, so as to be able to retain the seeds in place until reaching the releasing means.
6. A metering device according to claim 1, wherein the housing containing the metering disc forms a vacuum chamber together with one of the faces of the metering disc, the device being provided with vacuum generating means for lowering the air pressure on said face of the metering disc so as to capture and retain the seeds within the seed capturing and retaining means arranged on the face of the metering disc opposite the vacuum chamber.
7. A metering device according to claim 1, wherein the housing containing the metering disc forms a high pressure chamber together with one of the faces of the metering disc, the device being provided with blowing means for increasing air pressure on said face of the metering disc so as to capture and retain the seeds within the seed capturing and retaining means arranged on the same face of the metering disc.
8. A metering device according to claim 1, wherein the device further comprises a flexible sealing member contained within the housing, which is sealingly attached to the inner wall of the housing and which is sealingly pressed against one face of the metering disc, thus defining a vacuum chamber, the device being provided with vacuum generating means for lowering the air pressure on said vacuum chamber so as to capture and retain the seeds within the seed capturing and retaining means arranged on the face of the metering disc opposite the vacuum chamber.
9. A metering device according to claim 1, wherein the device further comprises
a concave plate within the housing, sealingly attached to one face of the seed metering disc, and coupled to the hollow shaft of the motor, thus defining a rotatable vacuum chamber,
vacuum generating means,
a non-rotatable tube or conduit, non-rotatably attached to the housing, which passes through the housing and the hollow shaft of the motor into the rotatable vacuum chamber, fluidly connecting the vacuum means to the rotatable vacuum chamber.
10. A metering device according to claim 6, wherein the motor is coupled to the seed metering disc by means of a hollow hub or other suitable coupling means comprising a hollow shaft or tube, and wherein the hollow hub is perforated, fluidly connecting the vacuum chamber to the hollow motor shaft of the motor coupled to said hollow hub.
11. A metering device according to claim 6, wherein the vacuum generating means are fluidly connected to the vacuum chamber through the hollow motor shaft of the motor and through the perforated hollow hub.
12. A metering device according to claim 6, wherein the vacuum generating means are fluidly connected to said vacuum chamber through an opening or orifice in the housing in a position other than the hollow shaft\u2014eccentrically regarding the metering disc\u2014and wherein the coupling means coupling the motor to the seed metering disk does not allow fluid connection between the vacuum chamber and the hollow shaft of the motor.
13. A metering device according to claim 9, wherein the releasing means comprises a plate, fixed to the non-rotatable tube or conduit and located within the rotatable vacuum chamber, which makes contact with a region of the face of the metering disc inside the rotatable vacuum chamber, blocking the orifices of the seed capturing and retaining means and therefore interrupting the vacuum applied to the seeds retained on the other face of the metering disk, making them drop into the conducting means towards the ground.
14. A metering device according to claim 8, wherein the vacuum chamber does not simultaneously overlap with all the seed capturing and retaining means of the metering disc and wherein the release of the seeds from the holes of the seed capturing and retaining means occurs when a particular hole of the seed retaining means no longer overlaps with the vacuum chamber.
15. A metering device according to claim 6, wherein the seed releasing means comprises a rotatable wheel contacting the metering disc on the face opposite the seeds capturing and retaining means, the wheel blocking the holes of the seed capturing and retaining means and therefore interrupting the vacuum applied to the retained seeds, making them drop into the conducting means towards the ground.
16. A metering device according to claim 1, wherein the motor is housed within the housing, fixed to the inner surface of the housing wall.
17. A metering device according to claim 1, wherein the motor is fixed to the outer surface of the housing wall.
18. A metering device according to claim 1, wherein the seed releasing means comprise stationary or mobile brushes that physically remove the seeds from the seed capturing and retaining means.
19. A metering device according to claim 1, wherein the device further comprises singulating means for allowing only one seed to be retained in each capturing and retaining means.
20. A metering device according to claim 19, wherein the singulating means comprise a plate, parallel to the metering disc and spaced apart so as to allow only one seed to be retained in each capturing and retaining means.
21. A metering device according to claim 1, wherein the conducting means for conducting the released seeds onto the ground comprises a conveyor belt provided with bristles for guiding the seeds to an outlet close to the soil and into an opened furrow in the soil.
22. A metering device according to claim 1, wherein the conducting means for conducting the released seeds onto the ground comprises a tube for allowing the seeds to freely reach the soil by gravity, into an opened furrow in the soil.
23. A metering device according to claim 1, wherein the seed capturing and retaining means of the seed metering disc comprises holes and the housing comprises a rotatable toothed wheel with a plurality of teeth or projections, that engage with said holes of the seed capturing and retaining means as the disc rotates, removing obstructions and releasing seeds stuck in said holes.
24. A metering device according to claim 1, wherein the motor is a large diameter annular torque motor with an annular rotor.
25. A metering device according to claim 7, wherein the motor is coupled to the seed metering disc by means of a hollow hub or other suitable coupling means comprising a hollow shaft or tube, and wherein the hollow hub is perforated, fluidly connecting the high pressure chamber to the hollow motor shaft of the motor coupled to said hollow hub.
26. A metering device according to claim 8, wherein the motor is coupled to the seed metering disc by means of a hollow hub or other suitable coupling means comprising a hollow shaft or tube, and wherein the hollow hub is perforated, fluidly connecting the vacuum chamber to the hollow motor shaft of the motor coupled to said hollow hub.
27. A metering device according to claim 7, wherein the blowing means are fluidly connected to the high pressure chamber through the hollow motor shaft of the motor and through the perforated hollow hub.
28. A metering device according to claim 8, wherein the vacuum generating means are fluidly connected to the vacuum chamber through the hollow motor shaft of the motor and through the perforated hollow hub.
29. A metering device according to any one of claim 7, wherein the blowing means are fluidly connected to said high pressure chamber through an opening or orifice in the housing in a position other than the hollow shaft\u2014eccentrically regarding the metering disc\u2014and wherein the coupling means coupling the motor to the seed metering disk does not allow fluid connection between the high pressure chamber and the hollow shaft of the motor.
30. A metering device according to claim 8, wherein the vacuum generating means are fluidly connected to said vacuum chamber through an opening or orifice in the housing in a position other than the hollow shaft\u2014eccentrically regarding the metering disc\u2014and wherein the coupling means coupling the motor to the seed metering disk does not allow fluid connection between the vacuum chamber and the hollow shaft of the motor.
31. A metering device according to claim 7, wherein the seed releasing means comprises a rotatable wheel contacting the metering disc on the face opposite the seeds capturing and retaining means, the wheel blocking the holes of the seed capturing and retaining means and therefore interrupting the pressure applied to the retained seeds, making them drop into the conducting means towards the ground.
32. A metering device according to claim 8, wherein the seed releasing means comprises a rotatable wheel contacting the metering disc on the face opposite the seeds capturing and retaining means, the wheel blocking the holes of the seed capturing and retaining means and therefore interrupting the vacuum applied to the retained seeds, making them drop into the conducting means towards the ground.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A process for producing ethanol from synthesis gas, comprising:
(a) reacting synthesis gas, said synthesis gas containing hydrogen and carbon monoxide, under conditions to provide a first reaction product including at least one ether, methanol, water, unreacted hydrogen, and unreacted carbon monoxide;
(b) condensing said first reaction product to produce a first condensate stream comprising water and methanol and a second stream comprising said at least one ether, said unreacted hydrogen, said unreacted carbon monoxide, and water;
(c) contacting said first condensate stream of step (b) with a desiccant, thereby removing water from said first condensate stream, thereby providing a stream comprising methanol;
(d) contacting said second stream of step (b) with a desiccant, thereby removing water from said second stream of step (b), thereby providing a stream comprising said at least one ether, said unreacted hydrogen, and said unreacted carbon monoxide;
(e) passing said stream comprising said at least one ether, said unreacted hydrogen, and said unreacted carbon monoxide of step (d) to a carbonylationhydrogenolysis reactor, wherein said carbonylationhydrogenolysis reactor contains a plurality of fixed catalyst beds, which contain said carbonylation catalyst and said hydrogenolysis catalyst, whereby said at least one ether, said unreacted hydrogen, and said unreacted carbon monoxide are reacted in the presence of a carbonylation catalyst selected from the group consisting of H-mordenite and Group VII metals, and a hydrogenolysis catalyst selected from the group consisting of copper chromite, copper oxide, and zinc oxide to provide a first ethanol product stream containing ethanol, methanol, methyl acetate, ethyl acetate, unconverted at least one ether, and unconverted synthesis gas;
(f) condensing said first ethanol product stream to provide an ethanol condensate stream comprising ethanol, methanol, methyl acetate, and ethyl acetate, and an unconverted material stream comprising unconverted at least one ether and unconverted synthesis gas;
(g) recycling said unconverted material stream of step (f) to step (e);
(h) distilling said ethanol condensate stream to provide a second ethanol product stream comprising ethanol and a first distillate stream comprising methanol, methyl acetate, and ethyl acetate;
(i) distilling said first distillate stream to produce a methanol stream comprising methanol and a second distillate stream comprising methyl acetate and ethyl acetate; and
(j) recycling second distillate stream of step (i) to step (e).
2. The process of claim 1, and further comprising:
recycling said stream comprising methanol of step (c) to step (a).
3. The process of claim 1, and further comprising:
recycling said methanol stream of step (i) to step (a).
4. The process of claim 1 wherein said hydrogen and said carbon monoxide of said synthesis gas of step (a) are reacted at a pressure of from about 250 psi to about 2,000 psi.
5. The process of claim 4 wherein said hydrogen and said carbon monoxide of said synthesis gas of step (a) are reacted at a pressure of from about 300 psi to about 900 psi.
6. The process of claim 1 wherein said hydrogen and said carbon monoxide of said synthesis gas of step (a) are reacted at a temperature of from about 100\xb0 C. to about 400\xb0 C.
7. The process of claim 6 wherein said hydrogen and said carbon monoxide of said synthesis gas of step (a) are reacted at a temperature of from about 150\xb0 C. to about 350\xb0 C.
8. The process of claim 1 wherein said hydrogen and said carbon monoxide are reacted in step (a) at a molar ratio of hydrogen to carbon monoxide of from about 0.6 to about 3.0.
9. The process of claim 1 wherein said at least one ether is dimethyl ether.
10. The process of claim 1 wherein step (a) comprises:
(i) reacting said hydrogen with said carbon monoxide of said synthesis gas to produce methanol; and
(ii) converting said methanol to said at least one ether, thereby providing said first reaction product including said at least one ether, said unreacted hydrogen, said unreacted carbon monoxide, unreacted methanol, and water.
11. The process of claim 10 wherein step (a) is conducted in the presence of a catalyst.
12. The process of claim 11 wherein said catalyst is selected from the group consisting of copper chromite, copper oxide, zinc oxide, and mixtures thereof.
13. The process of claim 12 wherein said catalyst is supported on a support selected from the group consisting of alumina and zeolites.
14. The process of claim 12 wherein said catalyst further includes a transition metal.
15. The process of claim 1 wherein step (e) comprises:
(i) reacting said at least one ether with carbon monoxide to produce at least one acetate comprising methyl acetate and ethyl acetate; and
(ii) subjecting said at least one acetate to hydrogenolysis to produce ethanol and methanol.
16. The process of claim 9 wherein, in step (e), said carbon monoxide and said dimethyl ether are fed to said carbonylationhydrogenolysis reactor at a molar ratio of carbon monoxide to dimethyl ether of from about 1:1 to about 20:1.
17. The process of claim 16 wherein, in step (e), said carbon monoxide and said dimethyl ether are fed to said carbonylationhydrogenolysis reactor at a molar ratio of carbon monoxide to dimethyl ether of from about 5:1 to about 10:1.
18. The process of claim 9 wherein, in step (e), said hydrogen and said dimethyl ether are fed to said carbonylationhydrogenoysis reactor at a molar ratio of hydrogen to dimethyl ether of from about 1:1 to about 20:1.
19. The process of claim 18 wherein, in step (e), said hydrogen and said dimethyl ether are fed to said carbonylationhydrogenolysis reactor at a molar ratio of hydrogen to dimethyl ether of from about 5:1 to about 10:1.
20. The process of claim 1 wherein, in step (e), carbon monoxide is fed to said carbonylationhydrogenolysis reactor at a gas hourly space velocity of from about 250 Ihr. to about 20,000 Ihr. per liter of catalyst.
21. The process of claim 20 wherein, in step (e), said carbon monoxide is fed to said carbonylationhydrogenolysis reactor at a gas hourly space velocity of from about 2,000 Ihr. to about 8,000 Ihr. per liter of catalyst.
22. The process of claim 1, wherein, in step (e), said hydrogen and said carbon monoxide are fed to said carbonylationhydrogenolysis reactor at a molar ratio of hydrogen to carbon monoxide of from about 0.6 to about 3.0.