DE19616177A1 - Coal dust power plant reserve operating mode method - Google Patents

Abstract

The mode is brought about due to the coal dust pulveriser and the coal dust burner switching out of operation in stages. An oil burner simultaneously switches into operation in stages. The burner has an intermittent operation to provide a reduced quantity of steam. The steam can be provided at between 5% and 20% of the normal level, at a temperature between 60% and 100% of normal and a pressure also between 60% and 100%.

Description

The invention relates to a method for operating a reserve power station block equipped with coal dust combustion.

For times of lower electrical energy requirements, e.g. B. at night times, it is necessary to separate blocks of a power plant kes or a power plant association from the Elektroenergie-Über separate grid. In doing so, the corresponding force plant block decommissioned. This decommissioning, especially the re-commissioning requires a high Cost, time and energy expenditure and leads to additional Chen loads on the components subject to creep stress (Lifetime reductions).

For this reason it is known to operate a station (Aus set operation) of the block by the fire power and thus the steam generation is significantly reduced. Of the Generated steam is generated via the machines without generating energy capacitors shut down. With a 500 MW block a steam volume of approx. 500 t / h (corresponds approximately to an equi valent electrical power generation of 150 MW), but not used, so that a considerable cost and energy wall is required.

It is known to reduce such expenses, one Steam boiler by means of opposite flow direction keep external steam warm (DD 2 65 211). This ver driving style, however, leads to the isolated main steam pipes maintain a high level of heat and the non-lockable heating surfaces due to the heat given off in the  Cool down the dead space. Because of these temperature differences a temperature when starting and reversing flow fall in the main steam lines inevitable.

Furthermore, it is known after decommissioning the furnace maintain an internal warming operation without generating steam received (DE 25 51 430). This procedure is with mo their large steam boilers are not feasible because they are not very big Have storage capacity and cool down quickly. A reserve operation and the subsequent start-up of the system proves turn out to be problematic.

The reserve practice for natural circulation steam boilers (DD 1 29 824) or for with natural and forced circulation heating surfaces Chen provided steam boilers (DE 22 14 299) is modern Large steam boiler not transferable.

The invention is therefore based on the object of providing a cost-, Energy and time-saving simple reserve procedure for one Power disconnected from the electrical power transmission network to develop a work block.

This is achieved in that the coals according to the invention dust mills and thus the coal dust burners gradually Taken into operation and at the same time gradually heating oil burner (pilot oil burner) put into operation and intermittent rend be driven, steam according to selectable parameters generated near the nominal parameters with a small amount and over High pressure bypass station, reheater, hot rail  as well as via the hot-rail reducing station in the steam supply network of the power plant is operated.

The invention ensures that at minimal Heat input keeps you warm for a very short recovery drive time using the steam generated at low other costs is possible.

The invention will be explained in more detail using an exemplary embodiment explained. The accompanying drawing shows schematically the Duo steam boiler system for a 500 MW unit.

The steam turbine 1 is via the live steam lines 2 ; 3 with the steam boilers 4 ; 5 connected. The gate valve 6 and the high-pressure diversion station 7 are arranged in the live steam line 2 . About the steam line 8 , the Frischdampflei device 2 is connected to the cold rail line 9 , which is integrated in the reheater 10 . The outlet of the inter mediate superheater 10 is connected via the hot rail line 11 to the medium-pressure part 12 of the turbine 1 . The low-pressure bypass station 13 , the gate valve 14 and the hot-rail reducing station 15 are arranged in this hot-rail line 11 . Via the line 16 , the outlet of the hot rail reducing station 15 is connected to the steam network 17 for supplying steam and supplying other external consumers. The line 18 connects the low-pressure bypass station 13 to the machine capacitors 19 .

The mode of action is as follows:
In times of low energy consumption, the steam boiler 4 is decommissioned and the turbine 1 continues to operate with the steam boiler 5 . The steam boiler 4 is closed by closing the slide 6 ; 14 ; 20 separated from the turbine 1 and placed in reserve. The steam generated by the steam boiler 4 is then fed into the reheater 10 via the diversion station 7 , steam line 8 and cold rail line 9 . Via the hot-rail line 11 , the hot-rail-reducing station 15 , the steam reaches the steam network 17 connected to other block units for internal steam supply. If the steam generation is greater than the consumption, the excess steam can be fed via the low-pressure diversion station 13 and the line 18 to the machine capacitors 19 , in which the heat is dissipated as dissipated heat.

In order to keep the heat loss low, the coal dust mills and associated coal dust burners of the steam boiler 4 are gradually taken out of operation, two to three heating oil burners are gradually started up and operated intermittently, so that fresh steam is generated in the steam boiler 4 with the following parameters:

• - Live steam volume: 100 t / h
• - Live steam temperature: 400 ° C
• - Live steam pressure: 100 bar

These parameters are freely selectable and have the greatest effect to drive close to the nominal parameters.  

This ensures that the steam boiler 4 in the Reservebe remains sufficiently warm for start-up operation and that additional material stresses on the components are kept low.

If the steam boiler 4 is to be coupled again to the turbine 1 , the starting operation is carried out in the reverse order of the reserve operation.

The following advantages are achieved by the invention:

• 1. Simple and safe reserve operation of a steam boiler in times of low energy consumption and load reductions.
• 2. Shortened restart of the in reserve operation Chen steam boiler when higher energy requirements occur.
• 3. Gentle driving style

Reference list

1 steam turbine
2 live steam line
3 live steam line
4 steam boilers
5 steam boilers
6 gate valves
7 high-pressure diversion station
8 steam pipe
9 Cold rail line
10 reheaters
11 Hot rail line
12 medium pressure part
13 low pressure bypass station
14 gate valve
15 Hot rail reduction station
16 line
17 steam network
18 management
19 machine capacitor

Claims (3)

1. A method for the reserve operation of a power plant block equipped with a coal dust combustion, characterized in that the coal dust mills and thus the coal dust burner are gradually taken out of operation and at the same time gradually heating oil burners (pilot oil burners) are started up and operated intermittently, with steam according to selectable parameters near the Nominal parameters are generated in small quantities and are fed into the power plant's self-supply steam network via the high-pressure bypass station, reheater, hot rail and hot rail reduction station. 2. The method according to claim 1, characterized in that the live steam according to the freely selectable parameters with a Quantity from 5% to 20%, a temperature from 60% to 100% and a pressure of 60% to 100% according to the nominal para meters is generated. 3. The method according to claim 1, characterized in that the steam generated in the start-up steam line and / or in the Machine capacitors is driven.