FIELD

[0001 ] The present invention relates to an assembly using a gas turbine to heat solid fuel materials to chemically alter the fuel to produce a high temperature gas phase and a solid charcoal / ash phase. The gas phase may or may not contain recoverable liquid products when cooled or pressurized.

BACKGROUND

[0002] Described in International Patent Application PCT/AU201 1/000740 is an assembly, employing an indirectly fired gas turbine, that utilises combustion of fuels such as coal, biomass, garbage and heavy fuel oils to produce electric power.

[0003] A disadvantage of the above described assembly is that it does not provide the best opportunity in respect of maximising thermal efficiency for a given amount of fuel to be obtained from combustible products such as low grade fuels such as coal, biomass, garbage and heavy fuel oils.

OBJECT OF INVENTION

[0004] It is the object of the present invention to overcome or substantially ameliorate the above disadvantage.

SUMMARY OF INVENTION

[0005] There is disclosed herein an assembly to produce charcoal products from an input combustible material that includes carbon, the assembly including:

a compressor to provide compressed air;

a turbine to receive the compressed air, with the compressed air being heated so that the turbine is driven by expansion and cooling of the heated compressed air and combustion products;

a kiln to receive the combustible material to produce charcoal and a combustible gas; a first delivery system to deliver the combustible material to the kiln; a cooling chamber to receive the gas from the kiln to cause condensable gases to condense and to provide non condensable gases under pressure; and

a second delivery system to deliver the noncondensable gas under pressure to the compressed air so that the noncondensed gas is combusted so that the compressed air is heated to drive the turbine with the combustion products to drive the turbine.

[0006] Preferably, the second delivery system is an augmentation combustion chamber to receive the compressed air from the compressor and the uncondensed gases, and to cause combustion thereof to produce the heated compressed air and combustion products to be delivered to the turbine, with the turbine being an indirectly fired turbine.

[0007] In an alternative preferred fonn, the noncondensable gases under pressure are mixed with the compressed air for deli very to the turbine, with the turbine being a direct gas fired turbine.

[0008] In one preferred form, the condensed gases are delivered to a further device, at which the gases now condensed can be fractionated to produce a fuel.

[0009] In one preferred form, the combustion gases leaving the turbine are at a temperature approximately 550°C, at a pressure of approximately 0.015BAR.

[0010] Preferably, the hot compressed air delivered to the turbine includes approximately 95% clean air and approximately 5% combustion products provided by the augmentation combustion chamber.

BRIEF DESCRIPTION OF DRAWINGS

[001 1] Preferred forms of the present invention will now be described by way of example with reference to the accompanying drawing that is a schematic diagram of an assembly, employing an indirect gas fired turbine assembly, that uses a low grade fuel.

DESCRIPTION OF EMBODIMENTS

[0012] In the accompanying drawing there is schematically depicted an assembly 10 that receives a fuel 1 1, via a first delivery system, that may be a low grade fuel such as biomass, garbage, coal and heavy bunker fuel oils. [0013] The assembly 10 includes an indirectly fired gas turbine 12 that receives a heated gas 13 under pressure, with the heated gas cooling and expanding to drive the turbine 12. The turbine 12 is attached to a compressor 14 via a shaft 15 so that the compressor 14 is driven to produce air under pressure 16.

[0014] Also connected to the compressor 14, via direct coupling or via a gearbox 17 and shafts 46, is an alternator 18 that is driven to produce electric power. Accordingly the turbine 12 drives both the compressor 14 and alternator 18.

[0015] The assembly 10 has a clean air input that provides air for the compressor 14 at atmospheric temperature and pressure.

[0016] Combustion gases 20 from the turbine 12 are delivered to a thermal

treating/depolymerisation ki ln 21. As the ki ln 21 does not require all of the heat energy to perform the duty some of the gas may or may not be diverted to a boiler 47 in order to raise steam for delivery to a steam turbine or other process needs.

[0017] The kiln 21 has a chamber 22 through the combustion gases 20 pass, and a further chamber 23 to which the fuel 1 1 is delivered, with the chamber 23 located within the chamber 22 to provide for the transfer of heat from the gases 20 to the fuel 1 1.

[0018] The fuel passing through the chamber 23 is raised in temperature, and in the essential absence of oxygen, so as to produce char and gases.

[0019] The fuel 1 1 is delivered to the chamber 23 via a hopper and metering device 24. The fuel 1 1 is caused to pass through the chamber 23 to be heated thereby so as to produce charcoal and gases 26 that include combustible gases.

[0020] The gases 26 are delivered to a cooling chamber 27. In the cooling chamber 27, at least part of the gases 26 are condensed, with the no-condensed gases 28 being delivered, by a second delivery system including a flow control valve 49, to an augmentation combustion chamber 29. The condensed gases (liquid) 30 are delivered to a further device or outlet 31, at which the gases 30 may be fractionated into products such as fuel, including crude oil. The chamber 27 includes a compressor that delivers the gases 28 under pressure to the chamber 29 via the flow control valve 49. [0021 ] Hot gases 32 from the chamber 22 are delivered to a cyclonic combustion chamber 33 together with some or all of the material leaving the chamber 23, that is charcoal product. This material 34 is delivered to the chamber 33 via a metering device 35. Excess charcoal material not required for the delivery of heat energy into the turbine 12 leaves the system and is cooled to make a charcoal product.

[0022] The combustion gases 36 from the chamber 33 are delivered to a heat exchanger assembly 37 that includes a radiant heat exchanger 38 and a convection heat exchanger 39. The compressed air 16 passes through the assembly 37 to be heated thereby.

[0023] The cooled gases 36 leaving the heat exchanger assembly 37 may then optionally be delivered to a flue gas outlet 40 and/or an inert dust disposal unit 41. However the gas 36 may also pass through a final flue gas cleaner 42 to be delivered to the outlet 40 or unit 41.

[0024] Ash from the chamber 33 is delivered to a quenched ash outlet 43.

[0025] Charcoal 44 from the char 25 is delivered to a charcoal product outlet 45.

[0026] Preferably the gas 20 has a temperature in the vicinity of 550°C and is at a pressure of approximately 0.015BAR. Preferably the gas 13 includes approximately 95% clean air and approximately 5% combustion products. Preferably the gas 13 is at a temperature of about 1120°C and a pressure of approximately 9.5BAR.

[0027] The gas 32 is about 400°C at a pressure of about 0.015BAR.

[0028] The gas 36 is at about 1400°C at a pressure of about 0.010BAR.

[0029] The compressed air 16 is at a temperature of about 250°C at a pressure of about 9.5BAR.

[0030] The gas 36 after leaving the assembly 37 is at approximately 350°C at a pressure of about 0BAR. At this point the residual heat energy in the gas may or may not be used to raise steam in boiler 48 in order to provide process steam or drive a turbine. If steam is raised it may flow to the boiler 47 to be superheated for turbine use.

[0031 ] The boilers 47 and 48 could also be used to heat other media, other than water, to recover energy. As an example, the boiler 47 and 48 could be used to heat oil for a heating system. [0032] The gas 32 is at about 400°C at a pressure of about 0.015BAR.

[0033] In the above described embodiment, the turbine 12 is an indirectly fired gas turbine. In an alternative preferred form, the turbine 12 is a directly fired gas turbine, with the gas 28 and compressed air 16 being delivered to the turbine 12, via a secondary delivery system that includes the valve 49, with the gas 28 being combusted to heat the compressed air, so that the heated compressed air and combustion gases drive the turbine 12.

[0034] The above described preferred embodiment has the advantage that the hot gas leaving the turbine 12 is used to provide heat for the kiln 21.

[0035] A further advantage of the above described preferred embodiment is that combustible gases 26 are used to provide a combustible gas for the augmentation chamber 39, while condensed liquids 30 may be fractionated into products resembling crude oil fractions and used as a fuel as internal combustion engines, etc.

[0036] The above described preferred embodiments have yet a still further advantag

raising the turbine inlet temperature results in thermal efficiency increases.