WO2015113136A1

WO2015113136A1 - Biomass gasification power generator

Info

Publication number: WO2015113136A1
Application number: PCT/CA2015/000040
Authority: WO
Inventors: Guy Gaudreault
Original assignee: Guy Gaudreault
Priority date: 2014-01-29
Filing date: 2015-01-27
Publication date: 2015-08-06
Also published as: GB201401537D0

Abstract

Biomass gasification power generator has a combustion chamber that produces hot air. The hot air circulates in a closed circuit around a combustion chamber. An air heat exchanger transfers heat to a liquid which circulates in a liquid closed circuit. The liquid is heated into a pressurized gas. The gas pressure is recorded and monitored by a pressure micro controller. The pressurized gas thus generated by the heat exchanger is used for moving a piston. A system recuperates the oil within the circuit. A method for generating heat and electricity from biomass is also provided.

Description

BIOMASS GASIFICATION POWER GENERATOR

Field of the Invention The present invention relates generally to energy generation but more particularly to a biomass gasification power generator and a method for operating same.

Background of the Invention Biomass generators are gaining in popularity due to their ecological and sustainable characteristics. Biomass generators are known in the art and use the organic Rankine cycle to convert heat into mechanical energy.

Summary of the Invention

It is an advantage of the present invention to provide a biomass generator using waste products from the forestry industry.

It is a further advantage of the present invention that the biomass generator burns the biomass directly (for e.g., wood logs, wood chips, and agricultural biomass) without first having to transform the biomass into a different matter.

It is yet a further advantage of the present invention that the biomass generator is not using another system to create electricity (for e.g., pyrolysis).

It is yet a further advantage to recuperate lubrificating oil used in the process.

In order to do so, the present invention consists of a combustion chamber that generates hot air which heats a liquid, which is subsequently used in an expander to generate electricity (direct current or alternating current). This direct current can then be converted into alternating current to power electrical appliances, lighting and, building communications. The present invention also produces heat that can be used to heat a residence and or pre-heat hot water.

In a first broad embodiment the invention therefore seeks to provide a biomass generator comprising: a hot air furnace that produces hot air; the hot air circulating in a closed circuit around a combustion chamber; an air heat exchanger that transfers heat to a liquid which circulates in a liquid closed circuit; the liquid is heated into a pressurized gas; the pressurized gas thus generated by the heat exchanger is used for moving a piston; an oil recuperator system recuperates the oil within the system.

In a second broad embodiment, the invention therefore seeks to provide a biomass gasification power generator system comprising: a combustion chamber for burning biomass to generate heat to warm air; an evaporator for using the hot air to convert a liquid into a gas; an expansion engine for expanding the gas to generate direct current or alternating current; and a condenser for condensing the gas back into a liquid.

Preferably, the expansion engine comprises an intake valve cam comprising an immovable cam. Preferably, the biomass gasification power generator system further comprises a pump for pumping the liquid from the expansion engine to the evaporator.

Preferably, the liquid comprises an organic liquid. Preferably, the liquid is at least one of ammonia, butane, isobutane, 1,1,1,3,3- pentafluoropropane, trichloromonofluoromethane, 2,2-dichloro-l,l,l-trifluoroethane, 1,1- dichloro-l-fluoroethane, l,l,2-trichloro-l,2,2-trifluoroethane, carbon dioxide, or 1,1,1,2- tetrafluoroethane. Preferably, the liquid is 1,1,1,3,3-pentafluoropropane.

Preferably, the biomass gasification power generator further comprises an inverter for converting the direct current to alternating current

Preferably, the expansion engine comprises an expansion chamber comprising insulating materials.

Preferably, the insulating materials comprise at least one of ceramics, stainless steel, and polytetrafluoroethylene.

Preferably, the expansion engine further comprises a level sensor for deterirtining the amount of oil in the expansion engine.

In a third broad embodiment, the invention therefore seeks to provide a method for generating heat and electricity from biomass comprising the steps: combusting biomass to create heat to warm air; using the hot air to heat a liquid and turn the liquid into a pressurized gas; expanding the pressurized gas to generate a mechanical force and create a low pressure gas; using the mechanical force to create a direct current; and cooling the low pressure gas into a liquid.

Preferably, each of the steps of method for generating heat and electricity from biomass is repeated.

Preferably, the expanding step takes place in an expansion engine.

Preferably, the expansion engine comprises an intake valve and an exhaust valve that are simultaneously open during start-up of the method.

Preferably, the method further comprises recovering oil from the cooling step to be used in the expanding step. Preferably, the liquid is an organic liquid.

Preferably, the liquid is at least one of ammonia, butane, isobutane, 1,1,1,3,3- pentafluoropropane, trichloromonofluoromethane, 2,2-dichloro-l,l_/l-trifluoroethane_/ 1,1- dichloro-l-fluoroethane, l,l,2-trichloro-l,2,2-trifluoroethane, carbon dioxide, or 1,1,1,2- tetrafluoroethane. Preferably, the liquid is 1,1,1,3,3-Pentafluoropropane.

Preferably, the biomass is at least one of wood logs, wood chips, and agricultural biomass. The foregoing and other objects, features, and advantages of this invention will become more readily apparent from the following detailed description of a preferred embodiment with reference to the accompanying drawings, wherein the preferred embodiment of the invention is shown and described, by way of examples. As will be realized, the invention is capable of other and different embodiments, and its several details are capable of modifications in various obvious respects, all without departing from the invention. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be discussed in relation to the drawings, in which:

FIG. 1 is a top view of an expansion engine of the present invention;

FIG. 2 is a cutaway side view of the expansion engine along line AA of Fig. 2;

FIG. 3 is a cutaway side view of the expansion engine along line BB of Fig. 2;

FIG. 4 is an isometric view of the cam and piston;

FIG. 5 is a schematic view of the lubrificating oil cycle;

FIG. 6 is two isometric views of the furnace; and

FIG. 7 is a cutaway side view of the expansion engine along line CC of Fig. 2. Detailed Description

Referring to FIGS. 1-8, a biomass generator system is shown. The biomass generator system includes a combustion chamber and an expansion engine (40).

The combustion chamber receives biomass (not shown) and burns it to produce hot air as is known in the art. Examples of suitable biomass include wood logs, wood chips, and agricultural biomass. The hot air produced circulates in a closed circuit around the combustion chamber and through other parts of the biomass generator system as discussed further below.

A piston (34) located inside an expansion engine (40) pushes a liquid (27) into an air heat exchanger (24) (evaporator) in which the liquid (27) is heated from the hot air form the combustion chamber. Preferably, the liquid (27) is an organic liquid. Preferably, the liquid (27) is at least one of ammonia, butane, isobutane, 1,1,1,3,3-pentafluoropropane, trichloromonofluoromethane, 2,2-dichloro-l,l,l-trifluoroethane, 1,1-dichloro-l-fluoroethane, l,l,2-trichloro-l,2,2-trifluoroethane, carbon dioxide, or 1,1,1,2-tetrafluoroethane. More preferably, the liquid (27) is 1,1,1,3,3-pentafluoropropane (HFC-245fa). HFC-245fa has a very low boiling point (15° C at 14.7 psi). The liquid (27) is thus heated into a pressurized gas (30). The gas pressure is recorded and monitored by a micro controller (not shown).

The pressurized gas (30) thus generated by the heat exchanger (24) exits via a line (80) to an inlet valve (18) of the expansion engine (40). This introduces a quantity of pressurized gas (30) which pushes a second piston (64) which is connected to a crankshaft (36) by way of a connecting rod (38). The crankshaft turns a generator (50). The camshaft (65) is connected to the crankshaft (36) in a crankshaft to camshaft ratio of 2:1. The camshaft (65) and the crankshaft (36) determine the gas expansion ratio. An exhaust cam (44) actuates an exhaust valve (90) and an intake valve cam (70) actuates an intake valve (18). Preferably, the intake valve cam (70) is an immovable cam so as to adapt to the various temperature conditions in which the biomass generator can be used (for e.g., North America, Africa, and Nordic countries). The intake valve (18) determines the quantity of gas that will enter the cylinder for expansion.

After the expansion of the high pressure gas in an expansion chamber (100), the low pressure gas is pushed by the piston (64) into the exhaust valve (90). The exhaust valve (90) is connected to a conduit (81) which directs the low pressure gas to the condenser (46). The gas is cooled with cold air or cold water so as to liquefy the gas. The liquid (27) is collected in a reservoir (RT) and then then pumped by pump (48) through conduit (83) to the expansion engine (40). The pump (48) is located inside the crankcase of the expansion engine (40) and is therefore lubricated by the expansion engine (40). Any oil leakage from the pump (48) will be inside the crankcase, which is connected to the condenser.

The pump (48) is driven by the crankshaft (36) of the expansion engine (40) with its rotation directly proportional to the rotation of the crankshaft (36) of the expansion engine (40). Since the pump (48) is driven by the crankshaft (36) of the expansion engine (40), the flow rate of the pump (48) can be increased or decreased by movement (either manually or automatic) of the piston (34). The return of the piston (34) in the suction phase is done by a spring (not shown) and is thrust by a cam (70). Since the piston (34) is not fixed to a rod, the spring makes it possible to avoid cavitation.

The intake valve (18) reduces the force needed for the spring to close the valve in order to reduce the friction of the mechanical components (reducing wear) and reducing the loss of mechanical energy. The intake valve (18) is provided with an immovable piston and an interchangeable seal in order to reduce maintenance expenses. The immovable piston balances the pressure upon opening and upon closing.

The pump (48) then directs the fluid through duct (82) into the evaporator (24) at a given pressure. The pump (48) is actuated by the camshaft (65), which is itself actuated by a pump cam (67) and the piston (34).

The heat from the condenser (46) can be used to heat a building (not shown) by using the condenser (46). The pump (48), actuated by the expansion engine (40) moves the liquid (27) so that it can be reused. The flow rate of the pump (48) is proportional to the rotational speed of the expansion engine (40). Its structure allows it to set the flow of the liquid (27) with each rotation of the expansion engine (40). Since the pump (48) is within the expansion engine (40), there is no need for a secured seal, a coupling, as well as an expensive magnetic drive, therefore significant cost reduction. However in other embodiments, the pump is separate from the expansion engine. The output of the pump (48) directs liquid (27) to the heat exchanger (24).

Thus the liquid (27) pressure at the outlet of the pump (48) is the same as that of the outlet of the heat exchanger (24), and the cycle repeats.

In order to assist in the start-up of the process, the intake valve (18) and the exhaust valve (90) are simultaneously open to permit the lower pressure gas to circulate in the expansion engine (40) to heat the mechanical components and thus preventing an inappropriate amount of condensation of the gas into liquid in while in the expansion engine (40). The expansion engine (40) speed is preferably set at 1,800 RPM for reasons of mechanical efficiency. However, other speeds could be used (for e.g., 900 - 1,800 RPM). A gear box (52) increases the speed to preferably 3,600 RPM for making the generator (50) more efficient. Preferably, the speed is doubled by the gear box (52). The generator (50) can be used to connect a direct current (DC) battery (54) that feeds to an inverter (56) to convert DC to AC. The advantage of DC is that it can be coupled with photovoltaic systems, wind, or tidal energy. A master micro controller (not shown) is used for the proper functioning of the entire biomass generator.

A common problem in biomass systems of the prior art is the accumulation of oil coming from the expansion engine (40). The gas (30) has a high affinity with oil and thus, a small amount of oil eventually leaks from the expansion engine (40) and goes into the heat exchanger (24). The liquid (27) evaporates but not the oil, which accumulates at the bottom of the heat exchanger (24). Oil in the heat exchanger (24) reduces the thermal transfer since that oil comes from the motor. Additionally, oil leaking from the motor will eventually cause the motor to run out of oil.

To recover this oil, a level sensor (LS) inside the expansion engine (40) triggers an oil recovery cycle by opening a first valve (VI) when the oil level is below a set point. The cycle is initiated when the pump (48) is disabled so as to allow the liquid (27) in the heat exchanger (24) to evaporate completely and allow the oil to remain at the bottom of the heat exchanger (24). When the pressure of the heat exchanger (24) reaches the set point, the opening of a third valve (V3) allows the oil back into the expansion engine (40).

To start the cycle of electricity production again, the valve (V3) is closed and the second valve (V2) is opened to allow the liquid (27) to reach the heat exchanger (24). After a setpoint (e.g., 10 minutes), both valves (VI, V2) are closed and the generator (50) is ready to operate again. For heat production only, both valves (VI, V2) are opened.

The scope of the claims should not be limited by the preferred embodiments set forth in the examples, but should be given the broadest interpretation consistent with the description as a whole.

Claims

1. A biomass generator comprising: a hot air furnace that produces hot air; the hot air circulating in a closed circuit around a combustion chamber; an air heat exchanger that transfers heat to a liquid which circulates in a liquid closed circuit; the liquid is heated into a pressurized gas; the pressurized gas thus generated by the heat exchanger is used for moving a piston; an oil recuperator system recuperates the oil within the system.

2. A biomass gasification power generator system comprising:

a combustion chamber for burning biomass to generate heat to warm air;

an evaporator for using the hot air to convert a liquid into a gas;

an expansion engine for expanding the gas to generate direct current or alternating current; and

a condenser for condensing the gas back into a liquid.

3. The biomass gasification power generator system according to Claim 2, wherein the expansion engine comprises an intake valve cam comprising an immovable cam.

4. The biomass gasification power generator system according to Claim 2 or Claim 3, further comprising a pump for pumping the liquid from the expansion engine to the evaporator.

5. The biomass gasification power generator system according to any one of Claims 2 to 4, wherein the liquid comprises an organic liquid.

6. The biomass gasification power generator system according to any one of Claims 2 to 4, wherein the liquid is at least one of ammonia, butane, isobutane, 1,1,1,3,3- pentafluoropropane, trichloromonofluoromethane, 2,2-dichloro-l,l,l-trifluoroethane, 1,1- dichloro-l-fluoroethane, l,l,2-trichloro-l,2,2-trifluoroethane, carbon dioxide, or 1,1,1,2- tetrafluoroethane.

7. The biomass gasification power generator system according to Claim 6, wherein the liquid is 1,1,1,3,3-pentafluoropropane.

8. The biomass gasification power generator system according to any one of Claims 2 to 7, further comprising an inverter for converting the direct current to the alternating current.

9. The biomass gasification power generator system according to any one of Claims 2 to 8, wherein the expansion engine comprises an expansion chamber comprising insulating materials.

10. The biomass gasification power generator system according to Claim 9, wherein the insulating materials comprise at least one of ceramics, stainless steel, and poly tetrafluoroethylene .

11. The biomass gasification power generator system according to any one of Claims 2 to 10, wherein the expansion engine further comprises a level sensor for determining the amount of oil in the expansion engine.

12. A method for generating heat and electricity from biomass comprising the steps: combusting biomass to create heat to warm air;

using the hot air to heat a liquid and turn the liquid into a pressurized gas;

expanding the pressurized gas to generate a mechanical force and create a low pressure gas;

using the mechanical force to create a direct current; and

cooling the low pressure gas into a liquid.

13. The method according to Claim 12, wherein each of the steps of the method is repeated.

14. The method according to Claim 13 or Claim 14, wherein the expanding step takes place in an expansion engine.

15. The method according to Claim 14, wherein the expansion engine comprises an intake valve and an exhaust valve that are simultaneously open during start-up of the method.

16. The method according to any one of Claims 12 to 15, further comprising recovering oil from the cooling step to be used in the expanding step.

17. The method according to any one of Claims 12 to 16, wherein the liquid is an organic liquid.

18. The method according to any one of Claims 12 to 16, wherein the liquid is at least one of ammonia, butane, isobutane, 1,1,1,3,3-pentafluoropropane, trichloromonofluoromethane, 2,2-dichloro-l,l,l-trifluoroethane, 1,1-dichloro-l- fluoroethane, l,l,2-trichloro-l,2,2-trifluoroethane, carbon dioxide, or 1,1,1,2- tetrafluoroethane.

19. The method according to Claim 18, wherein the liquid is 1,1,1,3,3- pentafluoropropane.

20. The method according to any one of Claims 12 to 19, wherein the biomass is at least one of wood logs, wood chips, and agricultural biomass.