JP4870039B2 - How to start the engine - Google Patents

Description

  The present invention relates to a method for starting an engine having an intake / exhaust valve that uses a gas containing tar (eg, woody biomass gas) as fuel.

  Various techniques using tar-containing gas such as woody biomass gas as fuel for an engine for driving a generator have been proposed (see, for example, Patent Documents 1 and 2).

  When the engine is operated using a gas containing tar as a fuel, the tar adhering to the intake valve during normal operation adheres to the gap between the valve stem and the valve stem guide while the engine is stopped. If the engine is started in the normal operation after the warm-up operation, it may cause troubles such as breakage of the push rod. Therefore, in order to be able to apply the above-described normal starting method, it is necessary to reduce the tar content to 10 ppm or less.

  However, in order to realize a tar content of 10 ppm or less, a special filter device for tar removal is provided on the gasifier side, or high performance with high tar removal efficiency as described in Patent Document 2, for example It is necessary to install additional tar reforming equipment. When the filter device is provided, not only the equipment cost increases, but also the complicated filter replacement work needs to be periodically executed, so that the work load and cost required for maintenance are also greatly increased. Similarly, additional installation of a high-performance tar reformer will lead to increased construction costs and maintenance work for the entire facility. In the conventional operation method, it is necessary to frequently disassemble and maintain the engine in order to remove tar, and the maintenance cost increases.

JP 2006-29243 A JP 2001-172648 A

  The present invention provides a method for starting an engine that does not require special equipment such as a filter or a tar reformer and does not require frequent disassembly and maintenance even when the tar content in the fuel gas is 10 ppm or more. The task is to do.

  The present invention is necessary for starting a normal operation after executing a primary operation in which an engine having an intake / exhaust valve using a gas containing tar as a fuel is rotated several times at a rotation speed of 10 rpm or less. Provided is a method for starting an engine characterized by shifting to a proper operation.

  After the primary operation, if the engine performs a warm-up operation, rotate the engine several times at a speed equal to or less than 1/2 of the warm-up operation speed, and the engine performs the warm-up operation. If not, it is preferable to shift to the operation required for starting the normal operation after further executing the secondary operation of rotating several times at a rotational speed of 1/2 or less of the idling rotational speed.

  The fuel supply valve is kept closed during the primary operation and the secondary operation.

  The primary operation can be executed by a cell motor or the like. The primary operation may be executed manually or with a dedicated motor.

  In the present invention, the primary action of rotating several times or more at an extremely low speed (10 rpm or less) at the start of the engine is executed, so that the resistance due to tar adhering to the gap between the valve stem and the valve guide is softened. Damage can be prevented. In normal startup, the push rod may be damaged because the rotational speed at startup is fast and the resistance of the sliding portion between the valve rod and the valve guide is large. Low speed after the primary operation (idling speed if the engine does not perform warm-up operation at a speed less than 1/2 of the warm-up speed if the engine performs warm-up operation) By further executing the secondary operation of rotating several times at a rotation speed of 1/2 or less of the number), the tar temperature of the sliding portion between the valve stem and the valve guide rises and the viscosity decreases. In addition, it is possible to prevent the intake valve from being damaged at the rotation speed during warm-up operation or normal operation. Therefore, according to the present invention, even when the tar content in the fuel gas is 10 ppm or more (for example, 100 ppm), there is no need to use a special device such as a filter or a tar reforming device, and tar removal is possible. Therefore, it is not necessary to disassemble and maintain the engine frequently, and maintenance costs can be reduced.

  Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 shows a dual fuel engine 1 which is an example of an engine (a reciprocating engine in this embodiment) to which a starting method of the present invention is applied. The dual fuel engine 1 has an intake / exhaust valve, can be operated using both woody biomass gas and liquid fuel as fuel, and drives the generator 2. However, the present invention can also be applied to engines for other uses than for generators.

  The woody biomass gas is supplied from the biomass gas supply source 3 to the dual fuel engine 1 via the first supply line 4, and the gas fuel supply capable of controlling the presence and the supply amount of the woody biomass to the first supply line 4. A valve 5 is arranged. Further, liquid fuel is supplied from the liquid fuel supply source 6 to the dual fuel engine 1 via the second supply line 7, and the liquid fuel that can control whether or not the liquid fuel is supplied and the supply amount are supplied to the second supply line 7. A supply valve 8 is arranged. Further, air is supplied from the air supply source 9 to the dual fuel engine 1 through the third supply line 10, and the third supply line 10 has an air supply valve 11 capable of controlling the presence / absence of air supply and the supply amount. Has been placed.

  The biomass gas supply source 3 includes a gasifier that generates woody biomass gas. The woody biomass gas supplied from the bi-biomass gas supply source 3 to the dual fuel engine 1 does not have to be of high quality and may contain 10 ppm or more (for example, about 100 ppm) tar. Therefore, it is not necessary to provide a special filter device or a high-performance tar reforming device in order to significantly reduce the tar content to 10 ppm or less.

  In addition to the cell motor 12, the dual fuel engine 1 includes a manual device 13 that rotates the engine by a manual operation. The control panel 14 controls operations of the gas fuel supply valve 5, the liquid fuel supply valve 8, the air supply valve 11, and the cell motor 12.

  Hereinafter, the starting method will be described with reference to the flowchart of FIG. 2 and the time charts of FIGS. 3 and 4.

  First, when the engine start button is turned on (step S1 in FIG. 2), both the gas fuel supply valve 5 and the liquid fuel supply valve 6 are kept closed (step S2 in FIG. 2), and the first The next operation is executed (step S3 in FIG. 2 and times t1 to t2 in FIG. 3).

  In the primary operation, the dual fuel engine 1 is moved by several revolutions (1 to 9 times) at an extremely low speed of 10 rpm or less. In the example of the primary operation shown in FIG. 4 (A), the operation of rotating an extremely low speed of 10 rpm or less for 0.2 seconds is repeated five times at a time interval of less than 10 seconds. However, the primary operation is not limited to the operation of the dual fuel engine 1 intermittently as shown in FIG. 4A, but may be the operation of operating the dual fuel engine 1 continuously. Further, the primary operation may be executed by the cell motor 12 or may be executed by a manual operation using the manual device 13, or a motor dedicated to the primary operation may be provided separately from the cell motor 12.

  Tar that adheres to the intake valve during the previous normal operation may stick to the gap between the valve stem and the valve guide, and the tar that sticks to the gap between the valve stem and the valve guide has a higher rotational speed. Shows large viscous resistance. In the primary operation, the dual fuel engine 1 is moved at an extremely low speed, so that the fixed state due to tar can be released and the push rod can be prevented from being damaged.

  After the completion of the primary operation, the secondary operation is executed (step S4 in FIG. 2 and times t2 to t3 in FIG. 3). In the secondary operation, the dual fuel engine 1 is rotated several times or more (three or more rotations) at a rotation speed that is 1/2 or less of the warm-up operation rotation speed and at least higher than the rotation speed of the primary operation. However, when the engine to which the operation method of the present invention is applied does not perform the warm-up operation, the rotation speed in the secondary operation is equal to or less than ½ of the idling rotation speed and at least the rotation speed of the primary operation. Is set to a rotational speed higher than. Thus, the rotational speed in the secondary operation differs depending on whether or not the engine performs the warm-up operation, and the warm-up operation rotational speed and the idling rotational speed. The warm-up operation rotational speed of the dual fuel engine 1 of the present embodiment is 800 rpm, and the rotational speed in the secondary operation is set in the range of, for example, 10 rpm to 100 rpm.

  In the example of the secondary operation shown in FIG. 4B, the operation of rotating at a low speed of about 10 to 100 rpm for only 2 to 3 seconds is repeated three times at a time interval of less than 10 seconds. However, the secondary operation is not limited to the operation of the dual fuel engine 1 intermittently as shown in FIG. 4B, but may be the operation of operating the dual fuel engine 1 continuously.

  Since the tar temperature of the sliding part of the valve stem and the valve guide is increased and the viscosity is reduced by performing low-speed rotation as the secondary operation after the fixed state is released by the primary operation, the warm-up operation rotational speed The intake valve can be prevented from being damaged.

  After completion of the secondary operation, the liquid fuel supply valve 8 is opened (step S5 in FIG. 2), and the warm-up operation is executed (step S6 in FIG. 2 and times t3 to t4 in FIG. 3). In this embodiment, the warm-up operation speed is 800 rpm and the warm-up operation time is 2 minutes. After completion of the secondary operation, the gas fuel supply valve 5 is opened (step S7 in FIG. 2, times t3 to t4 in FIG. 3), and a normal operation for power generation is started (step S in FIG. 2, FIG. 3 and after time t4). In the present embodiment, the rated rotational speed is 1500 rpm. The warm-up operation rotational speed and the rotational speed are not limited to those in the present embodiment, and differ depending on the engine standard to which the present invention is applied.

  According to the engine starting method of the present embodiment, the primary operation (step S3 in FIG. 2) of rotating several times at a very low speed (10 rpm or less) is executed, so that the engine sticks to the gap between the valve stem and the valve guide. It is possible to prevent the push rod from being damaged by the tar. Also, after the primary operation, if the engine speed is low (if the engine performs a warm-up operation, the engine speed is 1/2 or less of the warm-up operation speed and the engine does not perform the warm-up operation). By further executing a secondary operation (step S4 in FIG. 2) that is rotated several times at a rotation speed of 1/2 or less of the idling rotation speed), the tar of the sliding portion between the valve stem and the valve guide is reduced. Since the temperature rises and the viscosity decreases, it is possible to prevent the intake valve from being damaged at the rotational speed of the warm-up operation or the normal operation. Therefore, even when the tar content in the fuel gas is 10 ppm or more (for example, about 100 ppm), there is no need to use a special device such as a filter or a tar reformer, and the engine is frequently used for tar removal. The maintenance cost can be reduced without the need for disassembly and maintenance.

  The engine to which the present invention can be applied is not limited to a reciprocating engine as long as the engine has an intake / exhaust valve that uses a gas containing tar as fuel.

1 is a block diagram showing a dual fuel engine to which the present invention is applied. The flowchart for demonstrating the starting method of the engine concerning embodiment of this invention. The typical time chart for explaining the starting method of the engine concerning the embodiment of the present invention. (A) is a schematic time chart of primary operation, (B) is a schematic time chart of secondary operation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Dual fuel engine 2 Generator 3 Biomass gas supply source 4 1st supply line 5 Gas fuel supply valve 6 Liquid fuel supply source 7 2nd liquid supply line 8 Liquid fuel supply valve 9 Air supply source 10 3rd supply line 11 Air supply Valve 12 Cell motor 13 Manual device 14 Control panel

Claims (3)

In an engine starting method having an intake / exhaust valve that uses a gas containing tar as fuel,
After performing the primary operation of rotating several times at a rotational speed of 10 rpm or less, the operation moves to the operation necessary for starting normal operation ,
After the primary operation, if the engine performs a warm-up operation, rotate the engine several times at a speed equal to or less than 1/2 of the warm-up operation speed, and the engine performs the warm-up operation. If not, the secondary operation of rotating several times at a rotational speed of 1/2 or less of the idling rotational speed is further executed, and then the operation is shifted to the operation necessary for starting the normal operation. The engine start method according to 1. 2. The engine starting method according to claim 1 , wherein the fuel supply valve is kept closed during the primary operation and the secondary operation. The engine starting method according to claim 1 or 2, wherein the primary operation is executed by a cell motor or the like.

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