JP2008292119A - Power generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide power generator provided with steam supply equipment capable of achieving high cost performance by constantly maintaining maximum load operation in which a flow rate of generated steam is maximum. <P>SOLUTION: The power generator 1 generates primary superheated steam at a superheater 21 of a boiler 2, supplies it to a high pressure turbine 31, supplies secondary superheated steam which is generated by reheating the steam used in the high pressure turbine 31 at a reheater 22 to an intermediate pressure turbine 32, and supplies a part of the secondary superheated steam to the outside through a supply pipe 6. When the secondary superheated steam is supplied from the supply pipe 6 to the outside, the combustion of the boiler is controlled based on a steam flow rate of the primary superheated steam. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a power generation apparatus including a steam supply facility.

  For example, as a facility that modifies an existing steam turbine power generator and supplies steam to external customers, a boiler that generates superheated steam by burning fuel, a steam turbine that is supplied with superheated steam from the boiler, A generator driven via the steam turbine, a condenser that cools and condenses the superheated steam supplied to the steam turbine, and supplies a part of the superheated steam supplied from the boiler to the steam turbine. There is a known supply path that adjusts the amount of superheated steam supplied to the steam turbine with a pressure regulating valve so that the combustion load of the boiler is constant (see Patent Document 1).

According to such a steam supply facility, by adjusting the amount of steam introduced into the steam turbine, the steam pressure in the boiler is made constant, thereby making the combustion load of the boiler constant and responding to external requests. A predetermined amount of steam can be supplied.
JP 2006-242522 A

  However, even when the fuel flow rate is kept constant and the steam amount is adjusted with the pressure regulating valve so that the combustion load of the boiler is constant, the heat generation amount of the fuel slightly changes depending on the properties of the fuel. Therefore, assuming that the operation state of the boiler is the maximum load operation, when the amount of heat generated from the fuel increases, the boiler exceeds the maximum load. In order to avoid this, when an operation is performed with a constant boiler combustion load, the fuel flow rate is set to be lower than the maximum load. However, in such a setting, since the operation is performed with the amount of generated steam suppressed, the power generation amount is also suppressed.

  Therefore, the present invention provides a power generator that exhibits high cost performance by always maintaining the maximum load operation at which the flow rate of the generated steam is maximum in the power generator having the steam supply facility as described above. For the purpose.

  A power generator according to the present invention includes a boiler that burns fuel to generate superheated steam, a steam turbine that is supplied with superheated steam from the boiler, a generator that is driven via the steam turbine, and the steam turbine. In the power generator including a condenser that cools the supplied superheated steam and condenses, and a supply path that supplies a part of the superheated steam supplied from the boiler to the steam turbine, the boiler includes: A superheater that introduces condensate from the condenser to generate primary superheated steam and supplies it to the steam turbine, and introduces the primary superheated steam from the steam turbine to reheat and generates secondary superheated steam. A reheater that supplies the steam turbine with the primary superheated steam supplied from the superheater and the secondary superheated steam supplied from the reheater. And the supply path is a pipe that is branched from a supply pipe from the reheater to the secondary turbine and supplies a part of the secondary superheated steam to the outside. And the boiler controls combustion based on a steam flow rate of the primary superheated steam when the secondary superheated steam is supplied to the outside from the supply path.

  According to the power generator of the present invention, when the secondary superheated steam generated in the reheater is supplied to the outside via the supply path, the boiler flow is determined based on the steam flow rate of the primary superheated steam generated from the superheater. Control combustion. Here, the primary superheated steam generated from the superheater is the main superheated steam supplied from the boiler to the turbine side, and the influence of the fuel condition in the boiler, such as the amount of heat generated by the fuel changes depending on the properties of the fuel, etc. Easy to receive. However, in the present invention, by controlling the combustion based on the steam flow rate of the primary superheated steam, it is possible to always maintain a predetermined load operation while avoiding that the boiler exceeds the maximum load. it can.

  In a preferred aspect of the present invention, the boiler is a combustion device that controls the flow rate of fuel supplied to the boiler based on the amount of combustion heat of the fuel, and the steam flow rate of the primary superheated steam is greater than a predetermined steam flow rate. Is preferably corrected so that the amount of combustion heat is estimated to be large, and when the steam flow rate of the primary superheated steam is smaller than a predetermined steam flow rate, the amount of combustion heat is corrected to be estimated small. Thereby, the flow rate of the fuel supplied to the boiler can be controlled, and the steam flow rate of the primary superheated steam can always be a predetermined flow rate.

  This predetermined steam flow rate is preferably the maximum value of the steam flow rate of the primary superheated steam in a state where the boiler can be continuously operated at the maximum steam flow rate. Thereby, the boiler can always maintain the maximum load operation in which the flow rate of the primary superheated steam is maximized while avoiding the state where the maximum load is exceeded.

  Next, an embodiment of the present invention will be described with reference to the accompanying drawings.

  As shown in FIG. 1, the power generation apparatus 1 is supplied to a boiler 2 that generates superheated steam by burning fuel, a steam turbine 3 that is supplied with superheated steam generated in the boiler 2, and the steam turbine 3. A condenser 4 that cools the superheated steam and condenses from the steam, a generator 5 that is driven via the steam turbine 3, and a part of the steam that is supplied from the boiler 2 to the steam turbine 3 is supplied to the outside. And a supply pipe 6 as a supply path.

  The boiler 2 is a kind of heat exchanger that generates water and superheated steam by burning fuel such as coal, and in this embodiment, the boiler 2 is heated to heat the water introduced from the condenser 4. A superheater 21 that generates primary superheated steam, and a reheater 22 that reheats steam introduced from a high-pressure turbine 31 described later to generate secondary superheated steam.

  The steam turbine 3 includes a high-pressure turbine 31 as a primary turbine driven by primary superheated steam generated by the superheater 21 and a secondary turbine driven by secondary superheated steam reheated by the reheater 22. A pressure turbine 32 and a low pressure turbine 33 driven by exhaust from the intermediate pressure turbine 32 are provided.

  The outlet side of the superheater 21 of the boiler 2 and one end side of the high-pressure turbine 31 are communicated by the first steam pipe 11, and the other end side of the high-pressure turbine 31 and the inlet side of the reheater 22 are first connected. Two steam pipes 12 communicate with each other. Thereby, the primary superheated steam supplied from the superheater 21 is introduced into the high-pressure turbine 31, while the steam exhausted from the high-pressure turbine 31 is introduced into the reheater 22 to be resuperheated.

  Here, a flow rate sensor 7 for detecting the flow rate of superheated steam supplied from the superheater 21 to the high-pressure turbine 31 is provided on the upstream side of the first steam pipe 11.

  Further, the outlet side of the reheater 22 and one end side of the intermediate pressure turbine 32 are communicated with each other by a third steam pipe 13, and the supply pipe 6 is branched from the third steam pipe 13. The other end side of the intermediate pressure turbine 32 and the one end side of the low pressure turbine 33 are communicated with each other through the fourth steam pipe 14.

  Here, a reheat steam pressure regulating valve 15 is provided on the downstream side of the branch portion of the third steam pipe 13, and this regulating valve 15 is provided on the upstream side of the branch portion of the third steam pipe 13. The pressure sensor 16 is opened and closed according to the pressure detected. Thereby, the amount of steam introduced into the intermediate pressure turbine 32 is adjusted.

  The condenser 4 is provided at the lower end of the low-pressure turbine 33 and cools the steam in the low-pressure turbine 33 used to drive the generator 5 with cooling water (seawater) replenished from outside to return to water. (Condensing). The cooling water is appropriately replenished by a circulation pump 41 provided in a condenser replenishment water pipe communicating with the condenser 4. Condensate by the condenser 4 is sent to the deaerator 43 by the operation of the condensate pump 42, and is again introduced into the superheater 21 of the boiler 2 by the feed water pump 23.

  The generator 5 has a rotation shaft that is coaxial with each of the turbines 31, 32, and 33, and the shaft 5 is rotationally driven by each of the turbines 31, 32, and 33 to generate power.

  The supply pipe 6 branched from the third steam pipe 13 communicates with the equipment of the steam supply destination (customer) via the steam supply source valve 61 and the steam supply valve 62, thereby reheating. A portion of the reheated steam supplied from the vessel 22 is supplied to the customer's equipment. Further, a temperature reducer 63 is provided in the middle of the supply pipe 6, whereby the temperature of the steam supplied from the steam supply valve 62 is adjusted.

  Moreover, the electric power generating apparatus 1 is provided with the controller (illustration omitted) as a control part in order to control the fuel supply to the boiler 2, and operation | movement of the various valves 15, 61, 62 and the various sensors 7 and 16 mentioned above.

  Next, the operation of the power generator 1 will be described.

  First, the water introduced into the boiler 2 is superheated by the superheater 21 and becomes primary superheated steam. The primary superheated steam is introduced into the high pressure turbine 31 through the first steam pipe 11 to operate the high pressure turbine 31. The used steam is introduced into the reheater 22 of the boiler 2 through the second steam pipe 12, and is resuperheated to become secondary superheated steam.

  Next, the secondary superheated steam is supplied to the intermediate pressure turbine 32 through the third steam pipe 13, while a part of the steam is introduced into the branch pipe 6 from the branching section to the outside (customer) facility. Supplied.

  The steam introduced into the intermediate pressure turbine 32 operates the intermediate pressure turbine 32 and then is introduced into the low pressure turbine 33 via the fourth steam pipe 14 to operate the low pressure turbine 33. Thus, the high-pressure turbine 31, the intermediate-pressure turbine 32, and the low-pressure turbine 31 constituting the steam turbine 3 are operated to generate electric power by driving the generator 5. On the other hand, the steam used for the operation of the turbine 3 becomes condensate in the condenser 4 and is again introduced into the boiler 2.

  Next, boiler fuel flow control performed by the above-described controller will be described with reference to the flowchart shown in FIG.

  First, the controller determines whether secondary superheated steam is supplied to an external supply destination as a requirement for controlling the flow rate of fuel supplied to the boiler 2 (STEP 1).

  Normally, when only power generation is performed, the amount of fuel supplied to the boiler 2 is determined based on the load of the generator 5, but when the secondary superheated steam is supplied to an external facility, The amount of secondary superheated steam supplied to the intermediate pressure turbine 32 varies depending on the operation status of the facility and the load on the generator 5 varies.

  For this reason, in STEP 1, whether or not the secondary superheated steam is supplied to the outside is determined from the open / closed states of the steam supply source valve 61 and the steam supply valve 62, and if the secondary superheated steam is not supplied to the outside ( (NO in STEP 1), the automatic operation state in which the amount of fuel supplied to the boiler 2 is automatically controlled based on the load of the generator 5 is maintained (STEP 2).

  On the other hand, when the secondary superheated steam is supplied to the outside (YES in STEP 1), switching to manual operation is performed (STEP 3).

  When switching to the manual operation is performed, the operator is instructed to input the amount of fuel heat (fuel calorie) based on the fuel used (STEP 4). Here, the input heat quantity of fuel is an ideal heat quantity value predicted from the properties depending on the production location, storage state, etc. of the fuel used.

  Next, the operator is instructed to set the amount of generated steam (STEP 5). The generated steam amount set here is a primary superheated steam amount that is a main steam flow rate generated from the superheater 21 of the boiler 2, and the operator sets a value of the flow rate of the primary superheated steam. At this time, the operator sets the generated steam amount to the maximum value of the primary superheated steam flow rate (for example, 483 t / h disclosed in Patent Document 1) in a state where the boiler can continuously operate at the maximum steam flow rate. be able to.

  When the generated steam amount is set, the controller calculates the fuel supply amount from the generated steam amount and the fuel heat amount, and based on the fuel supply amount, the flow rate is such that fuel such as coal is fed into the boiler 2 at a predetermined flow rate. Take control.

  When the manual operation is started in this way, the controller determines that the flow rate of the primary superheated steam generated from the superheater 21 based on the detection value of the flow rate sensor 7 set in the first steam pipe 11 is the above STEP5. It is determined whether or not the steam amount set in step (6) is determined (STEP 6 and STEP 8).

  When the flow rate of the primary superheated steam is larger than the set steam amount (YES in STEP 6), correction is performed to increment the value of the fuel heat amount input in STEP 4 (STEP 7). Here, since the fuel heat quantity changes depending on the actual properties of the fuel, etc., correction for correcting the fuel heat quantity is performed based on the actual combustion state of the fuel. In particular, when the flow rate of the primary superheated steam is larger than the set flow rate, the amount of heat that is expected is generated by combustion in the boiler, so the fuel input to the boiler has a heat value that is greater than the set heat value. The correction which increments the value of the amount of combustion heat is performed.

  On the other hand, when the flow rate of the primary superheated steam is not larger than the set steam amount (NO in STEP6), it is determined whether or not the flow rate of the primary superheated steam is smaller than the set steam amount (STEP8). When the flow rate of the primary superheated steam is smaller than the set steam amount (YES in STEP 8), correction is performed to decrement the value of the fuel heat amount input in STEP 4 (STEP 9). Here, when the flow rate of the primary superheated steam is smaller than the set flow rate, the combustion in the boiler generates less heat than expected, so the fuel input to the boiler is smaller than the set combustion heat amount A correction for decrementing the value of the combustion heat amount is performed assuming that the heat amount is present.

  The correction amount may be a value corresponding to the deviation between the actual primary superheated steam flow rate and the set steam amount, or may be a predetermined minute value.

  As described above, when the fuel heat amount is incremented or decremented, the controller recalculates the fuel supply amount based on the corrected combustion heat amount, and the fuel such as coal is flown at a predetermined flow rate based on the calculated fuel supply amount. So that the boiler 2 is charged.

  On the other hand, when both of STEP 6 and STEP 8 are NO, that is, when the flow rate of the primary superheated steam is a predetermined flow rate, the fuel supply at the previous combustion supply amount is continued without correcting the fuel heat amount.

  Next, the controller confirms whether or not it is necessary to change the fuel heat amount or the generated steam amount due to the change of fuel (STEP 10). If no setting change is required, the controller returns to STEP 6 and returns to STEP 6 or lower. Repeat the process. On the other hand, if a setting change is necessary, the process returns to the beginning.

  As described above, the amount of heat generated by the fuel is monitored by the steam flow rate of the primary superheated steam, and control is performed so that the primary superheated steam has a predetermined flow rate, thereby avoiding that the boiler exceeds the maximum load. Thus, a predetermined load operation can be constantly maintained. In addition, this makes it possible to always maintain the maximum load operation in which the flow rate of the primary superheated steam is maximized, and to obtain high cost performance by making maximum use of the power generator.

The figure which shows the structure of the electric power generating apparatus as one Embodiment of this invention. The flowchart which shows the process of the electric power generating apparatus as one Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Power generation device, 2 ... Boiler, 3 ... Steam turbine, 4 ... Condenser, 5 ... Generator, 6 ... Supply piping, 7 ... Flow sensor, 11-14 ... Steam piping, 15 ... Reheat steam pressure regulating valve , 16 ... Pressure sensor, 21 ... Superheater, 22 ... Reheater, 31 ... High pressure turbine (primary steam turbine), 32 ... Medium pressure turbine (secondary steam turbine), 33 ... Low pressure turbine, 61 ... Steam supply source valve 62 ... Steam supply valve, 63 ... Temperature reducer.

Claims (3)

A boiler that generates superheated steam by burning fuel, a steam turbine that is supplied with superheated steam from the boiler, a generator that is driven via the steam turbine, and cooling the superheated steam that is supplied to the steam turbine In a power generator comprising a condenser for condensing and a supply path for supplying a part of superheated steam supplied from the boiler to the steam turbine,
The boiler introduces condensate from the condenser to generate primary superheated steam and supplies it to the steam turbine; introduces the primary superheated steam from the steam turbine and re-superheats the secondary superheated steam; A reheater that generates superheated steam and supplies it to the steam turbine;
The steam turbine has a primary turbine to which the primary superheated steam is supplied from the superheater, and a secondary turbine to which the secondary superheated steam is supplied from the reheater,
The supply path is a pipe that is branched from a supply pipe from the reheater to the secondary turbine and supplies a part of the secondary superheated steam to the outside.
The boiler controls combustion based on a steam flow rate of the primary superheated steam when the secondary superheated steam is supplied to the outside from the supply path. The power generator according to claim 1, wherein
The boiler is a combustion device that controls the flow rate of fuel supplied to the boiler based on the amount of combustion heat of fuel,
When the steam flow rate of the primary superheated steam is larger than a predetermined steam flow rate, the combustion heat quantity is corrected so as to be greatly estimated,
When the steam flow rate of the primary superheated steam is smaller than a predetermined steam flow rate, a correction is made so that the combustion heat quantity is estimated to be small. The power generator according to claim 2,
The predetermined steam flow rate is a maximum value of the steam flow rate of the primary superheated steam in a state where the boiler can be continuously operated at the maximum steam flow rate.