JPH05280707A - Superheater of waste heat recovery boiler in refuse incinerator - Google Patents

Abstract

PURPOSE:To offer a superheater of a waste heat recovery boiler in a refuse incinerator in which high-temperature corrosion on tube walls of the superheaters is prevented and the cost is reduced. CONSTITUTION:Superheaters 2, 3 and 4 are installed in a corrosive combustion gas flow path, and tube wall temperature detectors 18 and 17 are attached on the tube walls of the superheaters 2 and 3. When the tube wall temperature signals of the tube wall temperature detectors 18 and 17 exceed a specified temperature signal level, cooling water is introduced into the superheaters 2 and 3 by a superheat temperature reducing devices 14 and 12. Thereby, as cooling water is fed into the superheaters 2 and 3 by the superheat temperature reducing devices 14 and 12 when the tube wall temperatures of the superheaters 2 and 3 exceed the specified temperature, the tube wall is controlled to the specified temperature or lower to prevent high-temperature corrosion of the tube walls. In addition, the tube walls can be made of corrosion-resistant materials corresponding to gas temperatures without considering fluctuations in gas temperature, resulting in cost reduction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a superheater for a heat recovery boiler facility attached to an incinerator for incinerating, for example, municipal solid waste and industrial waste.

[0002]

2. Description of the Related Art In the above heat recovery boiler equipment, the steam generated in the boiler body is saturated steam, and some of it contains some water. A superheater composed of a plurality of superheater tube groups is used in order to evaporate this moisture, further proceed to superheat the whole, and supply high-temperature superheated steam to a steam turbine or the like. In addition, in order to precisely control the temperature of superheated steam supplied to a steam turbine or the like, in many cases,
Superheat desuperheater (superheat reducer) that mixes cooling water with superheated steam
Are using.

Further, in the heat recovery boiler equipment used in the incinerator for incinerating the above-mentioned municipal solid waste and industrial waste, since the superheater is installed in the environment of the combustion corrosive gas of the furnace, a plurality of superheater pipes are provided. The tube wall of the group is required to have corrosion resistance in its material, and the tube wall of the tube group installed on the high temperature side of the gas temperature is made of a material having higher corrosion resistance, that is, an expensive material, The pipe wall of the pipe group on the downstream side is made of a material having low corrosion resistance corresponding to the predetermined gas temperature, which is gradually lowered, that is, an inexpensive material, thereby improving the economical efficiency.

[0004]

However, when the temperature of the tube wall of the superheater rises above a predetermined value when the amount of gas and the gas temperature change due to changes in the combustion load and changes in the heat quantity of fuel, a high temperature is generated on the tube wall of the superheater. There was a risk of corrosion. Further, if the material of the tube wall of the superheater tube group is selected in consideration of this gas temperature fluctuation, there is a problem that a more excellent material having corrosion resistance is required and the economical efficiency is impaired.

The present invention solves the above problems,
It is an object of the present invention to provide a superheater for heat recovery boiler equipment, which prevents high temperature corrosion of the tube wall of the superheater and reduces costs.

[0006]

In order to solve the above problems, the superheater of the heat recovery boiler equipment in the refuse incinerator of the present invention comprises a plurality of superheater tubes arranged in a combustion corrosive gas environment of the refuse incinerator. A heat recovery boiler equipment superheater consisting of a group, the tube wall temperature detector is provided on the tube wall of the high temperature side tube group of the superheater, and the tube wall temperature signal of the tube wall temperature detector is a predetermined temperature signal. When the temperature exceeds the level, an overheat desuperheater for mixing cooling water is provided in the superheater.

[0007]

With the above construction, when the temperature of the tube wall of the high temperature side tube group becomes higher than the predetermined temperature by the superheat desuperheater, the cooling water is mixed in the tube group of the superheater and the tube wall of the high temperature side tube group is mixed. The temperature is suppressed below a predetermined temperature.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram of an arrangement structure of a superheater of a heat recovery boiler facility in a refuse incinerator according to an embodiment of the present invention.

Reference numeral 1 denotes a path of combustion corrosive gas supplied from a refuse incinerator (not shown). In this gas path 1, a high temperature superheater 2 and an intermediate temperature superheater are sequentially provided from the upstream side of the gas flow A. 3 and low-temperature superheater 4 are arranged, adjacent pipes are connected in series by connecting pipes 5 and 6, and connecting pipe 8 for steam supply from the drum 7 of the boiler is connected to the low-temperature superheater 4 to heat the high-temperature superheater. A steam extraction communication pipe 9 is connected to the vessel 2. With such arrangement of the superheater, the steam supplied from the drum 7 is sequentially heated to the low temperature superheater 4, the intermediate temperature superheater 3, and the high temperature superheater 2, and the superheated steam is passed through the steam extraction communication pipe 9. The gas supplied to the steam turbine or the like via the furnace and supplied from the furnace is cooled as it flows through the high temperature superheater 2, the intermediate temperature superheater 3, and the low temperature superheater 4. The high-temperature superheater 2, the medium-temperature superheater 3, and the low-temperature superheater 4 are each made of a corrosion-resistant material corresponding to the gas temperature, and are installed on the high temperature side.
That is, the high temperature superheater 2 is made of an expensive material having high corrosion resistance.

Further, a first superheat reducing device for mixing the cooling water supplied from the feed water pump 10 via the first flow rate adjusting valve 11 to the connecting pipe 5 of the medium temperature superheater 3 and the low temperature superheater 4 with the superheated steam. The warmer 12 is installed, and the connecting pipe 6 of the high-temperature superheater 2 and the intermediate-temperature superheater 3 is mixed with the superheated steam by the cooling water supplied from the water supply pump 10 through the second flow rate control valve 13. An overheat desuperheater 14 is installed.

The second superheat desuperheater 14 for the connecting pipe 6 is also provided.
The first steam temperature detector 15 is attached to the downstream side of the superheated steam flow of the above, the second steam temperature detector 16 is attached to the steam extraction communication pipe 9, and the gas flow A of the intermediate temperature superheater 3 is attached.
The first pipe wall temperature detector 17 is attached to the pipe wall on the most upstream side of, and the second pipe wall temperature detector 18 is attached to the pipe wall on the most upstream side of the gas flow A of the high temperature superheater 2. The temperature detection signals of the first steam temperature detector 15 and the first pipe wall temperature detector 17 are
The opening degree of the first flow rate control valve 11 is adjusted so that the first superheat desuperheater
It is input to the first temperature controller 19 that regulates the flow rate of the cooling water supplied to the second steam temperature detector 12, and is supplied to the second steam temperature detector 16 and the second steam temperature detector 16.
The temperature detection signal of the pipe wall temperature detector 18 of the second temperature adjusts the opening degree of the second flow rate control valve 13 to control the flow rate of the cooling water supplied to the second superheat desuperheater 14. Input to controller 20.

A functional block diagram of the first temperature controller 19 is shown in FIG. The temperature detection signal a of the first steam temperature detector 15 is input to the plus side of the first subtractor 22 via the advance circuit (1 + Ts) 21, and the inlet superheated steam temperature set value α of the high temperature superheater 2 is set. Is calculated and the deviation signal b is supplied to the first flow rate control valve composed of an integrator via the adder 23.
It is input to the drive circuit (1 / T) 24 of 11. In the first subtractor 22, when the deviation signal c of the output thereof causes the actual superheated steam temperature to become higher than the set superheated steam temperature, the first flow control valve 11
The inlet superheated steam temperature set value α is input on the minus side so as to send an open signal to the drive circuit 24 of. Further, the temperature detection signal c of the first pipe wall temperature detector 17 is the lead circuit (1+
Ts) 25 is input to the plus side of the second subtractor 26, the deviation from the pipe wall temperature set value β of the intermediate temperature superheater 3 is calculated, and the deviation signal d is a minus of the deviation output d. Limiter circuit that cuts so that the side is not output as a closed signal
27 and via the adder 23 to the drive circuit (1 / T) 24 of the first flow rate control valve 11 which is an integrator. In the second subtractor 22, when the deviation signal d of the output thereof is higher than the set tube wall temperature of the actual medium temperature superheater tube temperature, an open signal is sent to the drive circuit 24 of the first flow control valve 11. The tube wall temperature setting value β is input on the negative side. The lead circuits 21 and 25 are provided because the temperature response time is slow.

With the above configuration, when the actual superheated steam temperature becomes higher than the set superheated steam temperature α so that the inlet superheated steam temperature of the high temperature superheater 2 is usually set, the opening operation of the first flow control valve 11 is performed. Then, the cooling water is increased and mixed with the inlet superheated steam of the intermediate temperature superheater 3 to lower the temperature. Conversely, when the actual superheated steam temperature becomes lower than the set superheated steam temperature α, the first flow control valve 11 is closed. It operates to increase the temperature by reducing or shutting off the cooling water. Then, when the combustion load change, the gas amount and the gas temperature change due to the change in the fuel heat amount, and the actual medium temperature superheater pipe wall temperature rises above the set pipe wall temperature β,
The flow control valve 11 is opened to mix the cooling water with the superheated steam at the inlet of the intermediate temperature superheater 3 to lower the pipe wall temperature.

The structure of the second temperature controller 20 is the same as that of the first temperature controller 19, and the description thereof is omitted. The set value α is the outlet superheated steam temperature setting signal of the high temperature superheater 2, and the set value β is the pipe wall temperature setting signal of the high temperature superheater 2.

In this way, the temperature of the superheated steam supplied to the steam turbine or the like can be controlled so as to reach the set temperature, and the pipe wall temperatures of the high temperature superheater 2 and the intermediate temperature superheater 3 are detected and predetermined. Temperature controller to be below the value 1
By controlling with 9 and 20, it is possible to prevent the temperature rise of the tube wall of the high temperature superheater 2 and the intermediate temperature superheater 3 due to the change of the combustion load, the amount of gas due to the change of the fuel heat amount, and the change of the gas temperature. It is possible to prevent high temperature corrosion, and it is possible to manufacture these pipe walls with a corrosion-resistant material corresponding to a predetermined gas temperature without considering the fluctuation of the gas temperature, and it is possible to reduce the cost.

[0016]

As described above, according to the present invention, when the tube wall temperature of the high temperature side tube group becomes higher than the predetermined temperature by the superheat desuperheater, the cooling water is mixed in the tube group of the superheater. As a result, it is possible to suppress the temperature of the tube wall of the high temperature side tube group to a predetermined temperature or less, thus preventing high temperature corrosion of this tube wall, and further, without considering the fluctuation of gas temperature, this tube wall Can be made of a corrosion-resistant material corresponding to a predetermined gas temperature, and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an arrangement structure of a superheater of a heat recovery boiler facility in a refuse incinerator according to an embodiment of the present invention.

FIG. 2 is a block diagram of a temperature controller of a superheater of the heat recovery boiler facility.

[Explanation of symbols]

 1 Gas path 2 High temperature superheater 3 Medium temperature superheater 4 Low temperature superheater 5,6 Communication pipe 7 Drum 8 Steam supply communication pipe 9 Steam extraction communication pipe 10 Water supply pump 11,13 Flow control valve 12,14 Superheat desuperheater 15, 16 Steam temperature detector 17, 18 Pipe wall temperature detector 19, 20 Temperature controller

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Kazuhiko Minami 5-3-8 Nishikujo, Konohana-ku, Osaka City, Osaka Prefecture Hitachi Shipbuilding Co., Ltd. (72) Kenji Kashiwara, Nishikujo, 5-cho, Osaka, Osaka 3-28 Hitachi Shipbuilding Co., Ltd. (72) Inventor Masaharu Terashima 5-3-28 Nishikujo, Konohana-ku, Osaka City, Osaka Prefecture Hitachi Shipbuilding Co., Ltd.

Claims (1)

[Claims] 1. A superheater for a heat recovery boiler facility comprising a plurality of superheater tube groups arranged in a combustion corrosive gas environment of a refuse incinerator, the tube wall of the high temperature side tube group of the superheater. A pipe wall temperature detector is provided in the pipe wall temperature detector, and when the pipe wall temperature signal of the pipe wall temperature detector becomes equal to or higher than a predetermined temperature signal level, a superheat desuperheater that mixes cooling water into the tube group on the high temperature side of the superheater is installed. A superheater for a heat recovery boiler facility in a waste incinerator characterized by being installed.