JP6318009B2 - Biomass gas exclusive firing engine - Google Patents

Description

  The present invention relates to a biomass gas combustion engine that uses biomass gas.

2. Description of the Related Art Conventionally, a dual fuel engine using biomass gas and diesel fuel in combination is known as an engine used as a drive source for a cogeneration apparatus or a heat pump apparatus (see, for example, Patent Document 1).
The gasification furnace that supplies biomass gas to such a dual fuel engine will take time to generate biomass gas again if the gasification furnace is stopped. The operation will not be stopped until In addition, the amount of biomass gas generated and the calories burned are not constant and unstable.

  On the other hand, the dual fuel engine is started and stopped many times in accordance with the control conditions of the cogeneration device and the heat pump device.

  Therefore, if the amount of biomass gas generated is too high and the calorie burned is too high compared to the operating state of the dual fuel engine, or if the dual fuel engine is shut down, surplus gas is burned in the flare stack and the biomass When the amount of gas generated is small and the calorie burned is low, a stable operation state can be maintained by using diesel fuel to compensate for the shortage of biomass gas.

  In addition, since it becomes the structure which uses diesel fuel when biomass gas runs short, even if biomass gas runs short, a negative pressure will act on the supply path of biomass gas by the venturi effect. Therefore, the biomass gas supply path has a configuration in which the biomass gas hardly remains and the residue does not easily accumulate.

JP 2011-89070 A

  However, in the case of an engine that uses both biomass gas and diesel fuel and compensates for the shortage of biomass gas with diesel fuel, as in the conventional dual fuel engine described above, it does not use only biomass gas. Will not be able to fully demonstrate.

  For this reason, it is conceivable to use a gas engine that uses only biomass gas without using diesel fuel, but in this case, it will not be possible to apply negative pressure to the biomass gas supply path. Biomass gas remains and the residue tends to adhere to a pressure control valve such as a governor, increasing the frequency of maintenance.

  Biomass gas, in particular, is produced by producing raw material of biomass gas such as woody material by fermenting or fermenting in a gasification furnace, and then cooling to a usable temperature using a scrubber or the like, Since it is a gas with high humidity, if it stops in the supply path of biomass gas, the residue in biomass gas will be in the form of tar mixed with dew condensation water and will easily adhere. For this reason, the gas engine must be frequently maintained, resulting in a decrease in operating efficiency.

  In addition, every time the gas engine stops, it is possible to prevent biomass gas residue from adhering to the pressure control valve such as the governor by purging the biomass gas supply path in the vicinity of the pressure control valve such as the governor by air purging. However, in this case, when the gas engine is started again, the cell motor must continue to rotate for an extra time until the air existing in the biomass gas supply path is released, and a start-up congestion occurs. In addition, the burden on the cell motor is increased, and the life of the cell motor is shortened.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a biomass gas combustion engine that can reduce the frequency of maintenance and improve the operation efficiency without causing start-up congestion. It is said.

The biomass gas combustion engine according to the present invention for solving the above problems is configured such that biomass gas generated in a gasification furnace is supplied to the engine via a zero governor unit, and the zero governor unit includes a zero governor. After the supply of biomass gas from the gasifier is completed, the residual gas in the zero governor is purged with air and the supply of biomass gas from the gasifier is started. Only at the start of the first engine, control is performed to extend the normal cell operation time by the time of refilling with biomass gas corresponding to the volume of residual gas replaced by air purge, and from the gasifier. When the cell starts to rotate at the start of the first engine after the start of the supply of biomass gas, a predetermined opening degree than the set opening degree at the start time Only by rotating the cell valve opening drilled, the zero governor and gas pipe are air purged, after satisfying biomass gas again, the control unit is provided with valve opening is made to return to the set opening at startup It is what was done.

  The biomass gas exclusive combustion engine may be configured to fully open the valve opening when the valve opening is opened by a predetermined opening.

  As described above, according to the present invention, the zero governor unit is connected to the air supply path for purging the residual gas in the zero governor, and after the supply of biomass gas from the gasifier is completed, the residual gas in the zero governor is Only when starting the engine for the first time after starting the supply of biomass gas from the gasifier and recharging the biomass gas corresponding to the volume of residual gas replaced by the air purge, By controlling by the control unit to extend the normal cell operation time, it is possible to start the engine by preventing the residue in the biomass gas from becoming tar-like mixed with condensed water and adhering to the zero governor. . The extension of the cell operation time is only at the time of the first engine start after starting the supply of biomass gas from the gasifier after the air purge, so that it is possible to improve the operation efficiency of the engine without causing start-up congestion. At the same time, it is possible to prevent overuse of the cell and reduce the frequency of engine maintenance.

  In addition, when the supply of biomass gas from the gasifier starts and the cell starts to rotate when the engine starts for the first time, the cell is rotated at a valve opening that is a predetermined opening from the set opening at the start. The engine is operated without causing start-up congestion by controlling the valve opening so that it returns to the set opening at the time of start-up after the zero purger and the gas piping that have been purged with air are filled with biomass gas again. Efficiency can be improved.

  In addition, when opening the valve opening by a predetermined opening, by controlling the valve opening to be fully open, it is possible to minimize cell operation time and prevent cell consumption. This can further reduce the frequency of engine maintenance.

It is the schematic of the whole structure of the biomass gas exclusive combustion engine which concerns on this invention. It is a graph which shows the time-dependent change of the operation state of the gasification furnace of the biomass gas exclusive combustion engine which concerns on this invention, the timing of starting and a stop of an engine, and the timing of air purging a zero governor. Changes in the cell, shut-off valve, and engine speed over time when the engine in the biomass gas combustion engine according to the present invention is started by control and when biomass gas is supplied from the gasifier first. It is a graph explaining the difference. It is the schematic which shows the structure of the engine in the biomass gas exclusive combustion engine which concerns on this invention. In the biomass gas combustion engine according to the present invention, another embodiment of a cell, a shut-off valve, and an engine speed change over time when starting the engine for the first time after the supply of biomass gas from the gasification furnace is started. It is a graph to show.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows an outline of the overall configuration of the biomass gas exclusive combustion engine 1, and FIG. 2 shows the operation state of the gasifier 2 in the biomass gas exclusive combustion engine 1, the timing of starting and stopping the engine 4, and the zero governor 30 as air. FIG. 3 is a graph for explaining the relationship between the purge timing and the change over time, and FIG. 3 shows a case where the engine 4 in the biomass gas exclusive combustion engine 1 is started by control and when the operation of the gasification furnace 2 is started. FIG. 4 shows a configuration of the engine 4 in the biomass gas exclusive combustion engine 1. FIG. 4 shows a graph for explaining the difference in the changes in the rotational speeds of the cell 49, the gas cutoff valve 33 and the engine 4 with time.

  In the biomass gas combustion engine 1 according to the present invention, the biomass gas generated in the gasification furnace 2 is supplied to the engine 4 through the zero governor unit 3, and the zero governor unit 3 is purged of the residual gas in the zero governor 30 with air. An air supply path 32 is provided, and the controller 10 purges the residual gas in the zero governor 30 only after the engine 4 is stopped in conjunction with the end of the operation of the gasifier 2, and starts the operation of the gasifier 2. Control is performed so that the normal cell operation time is extended only by the time of filling the biomass gas corresponding to the volume of residual gas replaced by air purge only when the engine 4 is started in conjunction.

  The gasification furnace 2 is composed of a furnace that thermally decomposes biomass raw materials such as wood chips and rice husks, so that cracked gases such as hydrocarbons generated by thermal decomposition under low oxygen can be generated as biomass gas. Has been made.

  Since the biomass gas generated by the gasification furnace 2 is obtained by thermal decomposition, the temperature is high as it is. Therefore, a scrubber 21 configured to disperse water in the space is provided on the downstream side of the gasification furnace 2, and the biomass gas is cooled by passing the biomass gas through the scrubber 21. It is made so that.

  The biomass gas that has passed through the scrubber 21 is sent to the downstream side by the blower 23, but since the number of engines 4 to be connected differs according to the amount of biomass gas generated, one or more depending on the number of engines 4 to be connected. The data is branched and sent to a single location (two locations in this embodiment). At this time, the biomass gas is cooled by the scrubber 21 so that a large amount of moisture is contained. Therefore, a drain pot 24 is provided on the downstream side of the blower 23. The drain pot 24 collects condensed water contained in the biomass gas. The biomass gas from which the condensed water has been removed is supplied to the engine 4 via the zero governor unit 3. The gasification furnace 2, the scrubber 21, the blower 23, and the like are controlled by the control unit 10.

  The biomass gas that has passed through the drain pot 24 is supplied to the zero governor unit 3.

  The zero governor unit 3 is configured to supply biomass gas from the gasification furnace 2 to the engine 4 through a zero governor 30 provided in the gas supply path 31.

  A gas shutoff valve 33 is provided on the upstream end side of the gas supply path 31 so that the supply of biomass gas to the gas supply path 31 can be shut off. Further, a drain pot 34 is provided on the downstream end side of the gas supply path 31 so that condensed water contained in the biomass gas supplied to the engine 4 is recovered again.

  The zero governor 30 is provided in the gas supply path 31 between the gas shut-off valve 33 and the drain pot 34. The zero governor 30 is provided with a pressure regulating valve 30d in an atmospheric pressure release path 30c from the actuator 30b on the diaphragm 30a. By opening the pressure regulating valve 30d and releasing the atmospheric pressure release path 30c to the atmospheric pressure, the zero governor 30 converts the biomass gas supplied from the gas supply path 31 upstream from the zero governor 30 to the upstream side. Regardless of the supply pressure of the gas supply path 31, the gas supply path 31 on the downstream side of the zero governor 30 is supplied in an atmospheric pressure state.

  The air supply path 32 is connected to a gas supply path 31 between the gas cutoff valve 33 and the zero governor 30. The air supply path 32 and the gas supply path 31 are normally blocked by an air purge valve 35 provided on the air supply path 32 side, and this air purge valve 35 is used when air purge is required. Is opened and air purge is performed from the air supply path 32 to the zero governor 30 via the gas supply path 31. Therefore, an air purge blower 36 is provided on the upstream end side of the air supply path 32.

  A gas supply path 31 between the zero governor 30 and the drain pot 34 is provided with a discharge path 37 for discharging excess biomass gas to the flare stack 5. Excess biomass gas is combusted in the flare stack 5. The discharge path 37 is provided with an air purge relief valve 38. The air purge relief valve 38 is opened when the zero governor 30 is purged of air so that the air after air purge can escape from the gas supply path 31 to the outside via the discharge path 37. Has been made.

  When the inside of the zero governor 30 is purged with air, the gas shut-off valve 33 of the gas supply path 31 is closed, the air purge valve 35 of the air supply path 32 and the air purge relief valve 38 of the discharge path 37 are opened, and the air purge blower However, the air introduced into the gas supply path 31 is discharged from the atmospheric pressure release path 30c when the zero governor 30 is operated. Therefore, a bypass path 39 is provided between the atmospheric pressure release path 30 c of the zero governor 30 and the air supply path 32, and the air from the air purge blower 36 also acts on the atmospheric pressure release path 30 c of the zero governor 30. It is like that. Thus, the air from the air purge blower 36 is discharged from the air supply path 32 through the zero governor 30 to the outside through the air purge release valve 38 through the discharge path 37, and the zero governor 30 is purged with air. Become.

  An outlet 3 a corresponding to the downstream end of the gas supply path 31 of the zero governor unit 3 is connected to the A / F valve 41 of the engine 4. Thereby, the biomass gas that has passed through the drain pot 34 of the zero governor unit 3 can be supplied to the A / F valve 41 of the engine 4. The zero governor unit 3 is controlled by the control unit 10.

  In the engine 4, a mixer 40 for mixing air and biomass gas from the A / F valve 41 is provided in an intake passage 43 connected to the cylinder head 42, and between the mixer 40 and the cylinder head 42. A throttle valve 44 is provided. A silencer 46 is provided in the exhaust path 45 connected to the cylinder head 42, and a three-way catalyst 47 is provided between the silencer 46 and the cylinder head 42.

  The engine 4 is provided with an advance angle sensor 11 that detects the rotation angle of the crankshaft 48 and an energization sensor 12 that controls energization of the cell 49. Further, a front oxygen sensor 13 is provided on the exhaust gas inlet side of the three-way catalyst 47, and another rear oxygen sensor 14 is also provided on the outlet side. Further, an entire region sensor 15 is provided on the exhaust gas outlet side of the three-way catalyst 47.

  When starting the biomass gas combustion engine 1, the control unit 10 energizes the cell 49 of the engine 4 through the energization sensor 12, thereby detecting the rotation angle of the crankshaft 48 as to whether or not the engine 4 has been started. It can be detected by the advance sensor 11.

  In addition, the control unit 10 controls the amount of biomass gas generated in the gasification furnace 2 and the A / F valve 41 when the engine 4 is perturbed by stoichiometric operation using the biomass gas. It has a control map in which the relationship between the opening degree and the detection results from the front oxygen sensor 13, the rear oxygen sensor 14, and the whole area sensor 15 is input, and the stoichiometric operation of the engine 4 is determined according to the information of this control map. It is designed to control basation.

  Further, the control unit 10 controls the zero governor unit 3 to stop the operation of the gasification furnace 2 and the engine 4 and stop the air purge of the zero governor 30 when stopping the biomass gas combustion engine 1. Yes.

  Next, the control by the control part 10 of the biomass gas combustion engine 1 comprised in this way is demonstrated.

  As shown in FIG. 2, when the biomass gas exclusive combustion engine 1 is started, the control unit 10 starts the operation of the gasification furnace 2 and starts the engine 4 in conjunction therewith. However, even if the operation of the gasification furnace 2 is started, biomass gas sufficient to operate the engine 4 is not generated immediately. Therefore, the control unit 10 waits for the elapse of time T1 to reach the generation amount capable of supplying biomass gas. The engine 4 is started.

  Thereafter, once the gasification furnace 2 is stopped, it takes time to make the amount of biomass gas that can be supplied, so the controller 10 does not stop the biomass gas combustion engine 1. As long as the operation of the gasifier 2 is continued. On the other hand, the engine 4 is stopped or started according to the conditions set by the control unit 10 and is started and stopped many times during the day.

  And if the biomass gas exclusive combustion engine 1 is stopped, the control part 10 will stop both the gasification furnace 2 and the engine 4 in the stop program. At this time, the engine 4 is immediately stopped. However, since the gasification furnace 2 requires time T2 until the generation of biomass gas gradually converges after the stop, surplus biomass after the engine 4 is stopped. The gas is combusted in the flare stack 5. Further, the biomass gas remains in the zero governor 30 and the gas supply path 31 even after the time T <b> 2 when the generation of the biomass gas from the gasifier 2 converges. Although the remaining biomass gas passes through the drain pot 24 to remove the condensed water in the biomass gas, it passes through the scrubber 21 and thus has a high humidity near the saturated vapor pressure. Moreover, when the biomass gas exclusive combustion engine 1 is stopped and time elapses, the biomass gas remaining in the zero governor 30 and the gas supply path 31 is condensed with moisture in the residual gas due to a decrease in the environmental temperature. When this moisture is mixed with hydrocarbons constituting the composition of biomass gas and becomes a tar-like residue and adheres to the zero governor 30, the zero governor 30 malfunctions.

  Therefore, in the stop program of the biomass gas exclusive combustion engine 1, the control unit 10 determines that the gas shut-off valve 33 of the gas supply path 31 has passed the time T <b> 2 when the generation of the biomass gas from the gasifier 2 converges. Is closed, the air purge valve 35 of the air supply path 32 and the air purge relief valve 38 of the discharge path 37 are opened, and the air purge blower 36 is operated to control the air purge AP of the zero governor 30.

  Thereby, since the residual gas of the biomass gas in the zero governor 30 and the gas supply path 31 before and after that can be removed, the biomass gas exclusive combustion engine 1 can prevent the malfunction of the zero governor 30 due to the residual gas residue. . In addition, since the adhesion of residues can be prevented, the frequency of maintenance can be reduced.

  Note that when the air purge AP of the zero governor 30 is performed, residual gas of the biomass gas in the zero governor 30 and the gas supply path 31 before and after the zero governor 30 is removed. For the time S3 (see FIG. 3) for refilling the biomass gas corresponding to the capacity of the engine, the cell 49 is rotated longer than NS at the time of starting the normal engine 4 to expel the air in the gas supply path 31, and the biomass gas Need to be refilled.

  Accordingly, when the biomass gas exclusive combustion engine 1 is started again after the biomass gas exclusive combustion engine 1 is stopped, the control unit 10 starts supplying the biomass gas from the gasification furnace 2 and starts the first engine 4. Only the FS is controlled so that the cell 49 is rotated longer than NS at the time of starting the normal engine 4 for a time S3 corresponding to the refilling of the biomass gas corresponding to the capacity of the air purge AP. The engine 4 is started by expelling air from the supply path 31.

  Note that the air purge AP of the zero governor 30 may be performed every time the normal engine 4 is stopped. In this case, the biomass corresponding to the capacity of the air purge AP described above every NS when the normal engine 4 is started. The cell 49 must be rotated for a long time S3 for refilling the gas to refill the biomass gas, resulting in start-up congestion. In addition, the frequency of use of the cell 49 increases, and the consumption of the cell 49 becomes severe.

  In addition, the stop time from when the engine 4 started according to the conditions set by the control unit 10 during operation of the biomass gas exclusive combustion engine 1 is stopped until it is restarted is The stop time until the restart of operation, that is, the stop time from the stop of the operation of the gasification furnace 2 to the next restart of operation, is short and does not cause a temperature drop to cause condensation of moisture in the biomass gas. .

  Therefore, the air purge AP of the zero governor 30 is performed only after the biomass gas exclusive combustion engine 1 is stopped and the supply of biomass gas from the gasification furnace is completed.

  However, when the operation time of the biomass gas combustion engine 1 is a continuous operation over a long period of several days or weeks, the control unit 10 adjusts the zero governor 30 in accordance with the timing when the engine 4 is stopped by the control unit 10. The air purge AP may be controlled to be performed. In this case, when the engine 4 is started after the air purge AP of the zero governor 30 is performed, as described above, the cell 49 is rotated for a time corresponding to the refilling of the biomass gas corresponding to the capacity of the air purge AP. In addition, since the biomass gas must be refilled in the air purged AP space, it is preferable to perform control so that the air purge AP of the zero governor 30 is performed with sufficient timing for restart.

  As shown in FIG. 3, the engine 4 is started by the cell 49 by rotating the cell 49 to generate a negative pressure in the gas supply path 31 and then releasing the gas shut-off valve 33. As a result, the biomass gas is supplied to the engine 4 through the zero governor 30. At this time, when the engine 4 stopped by the control of the control unit 10 is restarted, that is, when the operation time of the cell 49 of the NS at the start of the normal engine 4 is S1, the engine 4 after the air purge of the zero governor 30 is In the case of restart, that is, when the supply of biomass gas from the gasifier 2 is started, the operation time S2 of the cell 49 of the FS at the start of the first engine 4 is refilled with biomass gas corresponding to the air purged capacity It is set to be longer than the operation time S1 of the normal cell 49 by the time S3 for the amount of time.

  As a result, the starting FS of the engine 4 after performing the air purge AP can be started comfortably in the same manner as the starting NS of the normal engine 4 that restarts the engine 4 by the control.

  However, in general, when the cell 49 is rotated, the A / F valve 41 of the engine 4 often has a valve opening comfortable for starting the engine 4. However, the reason why the operation time S2 of the cell 49 is increased after the air purge AP is to refill the gas supply path 31 and the zero governor 30 with biomass gas corresponding to the capacity of the air purge AP. Therefore, of the operating time S2 of the extended cell 49, the time S3 for refilling the biomass gas into the space purged with air purge AP, as shown in FIG. The opening of the A / F valve 41 is larger than the comfortable opening of the valve, for example, fully opened and the biomass gas is quickly refilled. The subsequent operation time of the cell 49 (S2-S3) The valve opening may be changed to a comfortable valve opening for starting the engine 4, and the valve opening may be changed to a comfortable valve opening for controlling the engine 4 after the engine 4 is started.

  By controlling in this way, the time S3 for refilling the biomass gas into the air purged AP space can be shortened, and the operation time S2 of the cell 49 that should originally be extended is further shortened. Will be able to. Therefore, the burden on the cell 49 can be reduced, the consumption of the cell 49 can be reduced, and start-up congestion can be made difficult to occur.

  The biomass gas combustion engine 1 configured in this manner can be suitably used as a drive source for a cogeneration apparatus (not shown). Moreover, it can be used suitably also as a drive source of a gas heat pump apparatus (illustration omitted).

  In addition, although the gasification furnace 2 is comprised by the furnace which heat-decomposes biomass raw materials, such as a wood chip and a rice husk, as this gasification furnace 2, it is not limited to the thing of a wood raw material, Other biomass raw materials such as plastic waste may be thermally decomposed. Moreover, it is not limited to what generates biomass gas by thermal decomposition, Even if it uses the fermentation type gasification furnace 2 which ferments raw garbage, sewage, manure, etc. and generates biomass gas Good. In the case of the fermentation gasification furnace 2, since the temperature rises by fermentation, a scrubber may be used for cooling the biomass gas. As in the case of the heat decomposition gasification furnace 2, the humidity is high and the tar-like state is used. Therefore, the present invention is effective because biomass gas which is liable to generate a residue is used.

DESCRIPTION OF SYMBOLS 1 Biomass gas exclusive combustion engine 10 Control part 2 Gasifier 3 Zero governor unit 30 Zero governor 32 Air supply path 4 Engine 41 A / F valve 49 Cell

Claims (2)

Biomass gas generated in the gasifier is supplied to the engine through the zero governor unit,
The zero governor unit is connected to an air supply path that purges the residual gas in the zero governor.
After the supply of biomass gas from the gasifier, the residual gas in the zero governor is purged with air,
Normal cell operation time only for the time of refilling with biomass gas equivalent to the volume of residual gas replaced by air purge only at the start of the first engine after starting the supply of biomass gas from the gasifier At the beginning of the start of the cell when starting the supply of biomass gas from the gasification furnace and starting the first engine, the opening was opened by a predetermined opening than the set opening at the start Rotating the cell at the valve opening, and after the air purged zero governor and gas piping were filled with biomass gas again, the control unit was set so that the valve opening returned to the set opening at the start. A biomass gas combustion engine characterized by The biomass gas combustion engine according to claim 1, wherein when the valve opening is opened by a predetermined opening, the valve opening is fully opened .

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