1. An external bed type double-fluidized bed system for preventing boiler contamination, comprising a fluidized bed combustion furnace (4), a cyclone separator (5), a coal ash distributor (6) and a fluidized bed pyrolysis furnace (8), wherein the outlet on the upper end of a side wall of the fluidized bed combustion furnace (4) is connected with the inlet of the cyclone separator (5), the cyclone separator (5) separates the high-temperature coal ash from the fluidized bed combustion furnace (4); the outlet on the bottom of the cyclone separator (5) is connected with the inlet of the coal ash distributor (6) to feed the separated high-temperature coal ash into the coal ash distributor (6), a smoke outlet is provided on the top of the cyclone separator (5); a first coal ash outlet and a second coal ash outlet are provided on the coal ash distributor (6), the first coal ash outlet is connected with the coal ash inlet on a side wall of the fluidized bed combustion furnace (4) through a return feeder (13), and the second coal ash outlet is connected with the coal ash inlet on a side wall of the fluidized bed pyrolysis furnace (8); a pyrolysis gas outlet is provided on the upper end of a side wall of the fluidized bed pyrolysis furnace (8), a raw coal inlet is provided in the middle or on the lower part of a side wall of the fluidized bed pyrolysis furnace (8); a coke-coal ash mixture outlet is provided on the lower end of a side wall of the fluidized bed pyrolysis furnace (8), the coke-coal ash mixture outlet is connected with the return feeder (13) through an external bed (15) and further connected with the coal ash inlet of the fluidized bed combustion furnace (4) through the return feeder (13).
2. The external bed type double-fluidized bed system for preventing boiler contamination according to claim 1, further comprising a cleaner (14) and a pyrolysis separator (7), a pyrolysis gas inlet is provided on the side wall of the pyrolysis separator (7), a pyrolysis gas outlet is provided on the top of the pyrolysis separator (7), and a pyrolyzed coal ash outlet is provided on the bottom of the pyrolysis separator (7) for separating the obtained pyrolyzed coal ash; the pyrolysis gas inlet of the pyrolysis separator (7) is connected with the pyrolysis gas outlet on the fluidized bed pyrolysis furnace (8), the pyrolysis gas outlet of the pyrolysis separator (7) is connected with the inlet of the cleaner (14), the pyrolyzed coal ash outlet of the pyrolysis separator (7) is connected with an external bed (15) and further connected with the return feeder (13) through the external bed (15), and the return feeder (13) is connected with the fluidized bed combustion furnace (4).
3. The external bed type double-fluidized bed system for preventing boiler contamination according to claim 1, wherein the smoke outlet on the top of the cyclone separator (5) is connected with the bottom of the fluidized bed pyrolysis furnace (8) through a second blower (12) to feed the separated high-temperature smoke into the fluidized bed pyrolysis furnace (8).
4. The external bed type double-fluidized bed system for preventing boiler contamination according to claim 3, wherein the smoke outlet of the cyclone separator (5) is connected with a chimney through a draught fan (11).
5. The external bed type double-fluidized bed system for preventing boiler contamination according to claim 4, wherein the coal ash outlet of the fluidized bed pyrolysis furnace (8) is connected with the external bed (15), the external bed (15) is connected with the coal ash inlet on a side wall of the fluidized bed combustion furnace (4) through the same return feeder (13).
6. The external bed type double-fluidized bed system for preventing boiler contamination according to claim 5, wherein the fluidized bed combustion furnace (4) is connected with the first feeder (2) which is provided with a first coal hopper (1).
7. The external bed type double-fluidized bed system for preventing boiler contamination according to claim 2, wherein the outlet of the cleaner (14) is connected with the pyrolysis gas inlet on a side wall of the fluidized bed combustion furnace (4).
8. The external bed type double-fluidized bed system for preventing boiler contamination according to claim 7, wherein the raw coal inlet of the fluidized bed pyrolysis furnace (8) is connected with a second feeder (10) which is provided with a second coal hopper (9).
9. The external bed type double-fluidized bed system for preventing boiler contamination according to claim 8, wherein the working process of the system is as follows:
a pyrolyzed semi-coke is combusted with air in the chamber of the fluidized bed combustion furnace (4), the resulting coal ash and smoke enters the cyclone separator (5) to be separated, one part of the separated smoke is fed into the fluidized bed pyrolysis furnace (8) through the second blower (12) while the other part is discharged from the chimney through the draught fan (11); the separated coal ash enters the coal ash distributor (6) to be divided into two parts according to the need of the fluidized bed pyrolysis furnace (8): one part is directly returned to the chamber of the fluidized bed combustion furnace (4) by the return feeder (13) through the first coal ash outlet while the other part enters the fluidized bed pyrolysis furnace (8) through the second coal ash outlet to be mixed with the high-alkalinity coals from the second coal hopper (9) and the second feeder (10) and then pyrolyzed in the fluidized bed pyrolysis furnace (8), the sodium contained in the gas resulting from the pyrolysis is removed using the cleaner (14), then the gas enters the fluidized bed combustion furnace (4) to be combusted; the pyrolyzed hot ash and high-alkalinity semi-coke enters the external bed (15) to be exchanged heat, after the temperature of the hot ash and the high-alkalinity semi-coke is adjusted, the hot ash and the high-alkalinity semi-coke enter the return feeder (13) through the external bed (15) and is then fed into the fluidized bed combustion furnace (4) by smoke to be combusted herein; the slag discharging of the boiler is carried out on the bottom of the fluidized bed combustion furnace (4); most of volatilizable sodium is removed after the high-alkalinity coals are pyrolyzed in the fluidized bed pyrolysis furnace (8), as the sodium content of the high-alkalinity coals is reduced, there is almost no contamination.
10. The external bed type double-fluidized bed system for preventing boiler contamination according to claim 2, wherein the smoke outlet on the top of the cyclone separator (5) is connected with the bottom of the fluidized bed pyrolysis furnace (8) through a second blower (12) to feed the separated high-temperature smoke into the fluidized bed pyrolysis furnace (8).
11. The external bed type double-fluidized bed system for preventing boiler contamination according to claim 10, wherein the smoke outlet of the cyclone separator (5) is connected with a chimney through a draught fan (11).
12. The external bed type double-fluidized bed system for preventing boiler contamination according to claim 11, wherein the coal ash outlet of the fluidized bed pyrolysis furnace (8) is connected with the external bed (15), the external bed (15) is connected with the coal ash inlet on a side wall of the fluidized bed combustion furnace (4) through the same return feeder (13).
13. The external bed type double-fluidized bed system for preventing boiler contamination according to claim 12, wherein the fluidized bed combustion furnace (4) is connected with the first feeder (2) which is provided with a first coal hopper (1).
14. The external bed type double-fluidized bed system for preventing boiler contamination according to claim 12, wherein the outlet of the cleaner (14) is connected with the pyrolysis gas inlet on a side wall of the fluidized bed combustion furnace (4).
15. The external bed type double-fluidized bed system for preventing boiler contamination according to claim 14, wherein the raw coal inlet of the fluidized bed pyrolysis furnace (8) is connected with a second feeder (10) which is provided with a second coal hopper (9).
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 structure, comprising:
a multiplexer having a plurality of input terminals, an output terminal, and a select terminal;
a memory element having a data input terminal coupled to the output terminal of the multiplexer, a clock input terminal, and a data output terminal;
a multiplexer control circuit having a first output terminal coupled to the select terminal of the multiplexer and further having a second output terminal; and
a clock control circuit having a first input terminal coupled to receive a control signal; a second input terminal coupled to the second output terminal of the multiplexer control circuit, and a first clock output terminal coupled to the clock input terminal of the memory element.
2. The structure of claim 1, wherein the clock control circuit further comprises a second clock output terminal, and wherein the memory element comprises:
a master latch having an input terminal coupled to the data input terminal of the memory element, a clock terminal coupled to the first clock output terminal of the clock control circuit, and an output terminal; and
a slave latch having an input terminal coupled to the output terminal of the master latch, a clock terminal coupled to the second clock output terminal of the clock control circuit, and an output terminal coupled to the data output terminal of the memory element.
3. The structure of claim 1, wherein the clock control circuit further comprises a second clock output terminal, and wherein the structure further comprises:
a setreset control circuit having an input terminal coupled to the second clock output terminal of the clock control circuit, and further having an output terminal coupled to provide a data signal to the memory element.
4. The structure of claim 1, wherein the memory element comprises a circuit configurable as a flip-flop and further configurable as a latch.
5. The structure of claim 1, wherein the multiplexer control circuit comprises at least one memory cell, the at least one memory cell controlling a value provided to the clock control circuit via the second output terminal of the multiplexer control circuit.
6. The structure of claim 1, wherein the structure comprises a programmable logic device (PLD), and the at least one memory cell comprises a configuration memory cell of the PLD.
7. The structure of claim 6, wherein the PLD comprises an FPGA.
8. A structure, comprising:
a memory element having a data input terminal and a clock input terminal;
first means for selecting at most one of a plurality of data values and providing the selected data value to the data input terminal of the memory element, wherein in a first state the first means selects one of the data values, and in a second state the first means selects none of the data values; and
second means for providing a clock edge to the clock input terminal of the memory element when the first means is in the first state, and not providing the clock edge to the clock input terminal of the memory element when the first means is in the second state.
9. The structure of claim 8, wherein the first means comprises a programmable multiplexer.
10. The structure of claim 8, further comprising means for initializing the memory element to a known value in response to an initialization signal when the first means is in the first state, and not initializing the memory element to the known value in response to the initialization signal when the first means is in the second state.
11. The structure of claim 8, further comprising means for setting contents of the memory element to a high value in response to a set signal when the first means is in the first state, and not setting the contents of the memory element to the high value in response to the set signal when the first means is in the second state.
12. The structure of claim 8, further comprising means for resetting contents of the memory element to a low value in response to a reset signal when the first means is in the first state, and not resetting the contents of the memory element to the low value in response to the reset signal when the first means is in the second state.
13. The structure of claim 8, wherein the first means comprises at least one programmable memory cell, and wherein the second means comprises means for detecting that a predetermined value is stored in the at least one programmable memory cell.
14. The structure of claim 8, wherein the structure comprises a programmable logic device (PLD), and the first means comprises a multiplexer controlled by at least one configuration memory cell of the PLD.
15. A programmable logic device (PLD), comprising:
a memory element having a data input terminal and a clock input terminal;
a multiplexer having a plurality of data input terminals, and further having an output terminal coupled to the data input terminal of the memory element;
means for programmably controlling the multiplexer to decouple all of the data input terminals from the output terminal of the multiplexer; and
means for decoupling the clock input terminal of the memory element from a clock signal source when the multiplexer is programmably controlled to decouple all of the data input terminals from the output terminal of the multiplexer.
16. The PLD of claim 15, further comprising means for initializing the memory element to a known value in response to an initialization signal when the multiplexer is not programmably controlled to decouple all of the data input terminals from the output terminal of the multiplexer, and not initializing the memory element to the known value in response to the initialization signal when the multiplexer is programmably controlled to decouple all of the data input terminals from the output terminal of the multiplexer.
17. The PLD of claim 15, further comprising means for setting the contents of the memory element to a high value in response to a set signal when the multiplexer is not programmably controlled to decouple all of the data input terminals from the output terminal of the multiplexer, and not setting the contents of the memory element to the high value in response to the set signal when the multiplexer is programmably controlled to decouple all of the data input terminals from the output terminal of the multiplexer.
18. The PLD of claim 15, further comprising means for resetting the contents of the memory element to a low value in response to a reset signal when the multiplexer is not programmably controlled to decouple all of the data input terminals from the output terminal of the multiplexer, and not resetting the contents of the memory element to the low value in response to the reset signal when the multiplexer is programmably controlled to decouple all of the data input terminals from the output terminal of the multiplexer.
19. The PLD of claim 15, wherein the means for programmably controlling the multiplexer comprises at least one configuration memory cell of the PLD, and wherein the means for decoupling the clock input terminal of the memory element from a clock signal source comprises means for detecting that a predetermined value is stored in the at least one configuration memory cell.
20. The PLD of claim 15, wherein the PLD comprises a field programmable gate array (FPGA).