JPS6066001A - Electric power plant in paper-making plant - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power plant in a paper mill that improves reliability against corrosion problems in a paper mill and provides the necessary power wind.

In pulp and paper Jilt plants, personnel, on-site steam, water and power are consumed. A significant portion of this steam and electricity is provided by chemical recovery boilers.

This chemical recovery boiler uses a spray gun to supply pulp cooking liquor (hereinafter referred to as black liquor) discharged during the valve manufacturing process to the combustion chamber of the boiler furnace, where it is dried in a high-temperature reducing atmosphere. The char bed is deposited at the bottom of the combustion chamber and burned to reduce the inorganic chemicals in the black liquor and recover Na2S and Na2CO3.The heat of combustion and the heat retained in the combustion gas are recovered to produce steam. This steam is used for in-house steam generation and power generation. However, there is a possibility that high-temperature corrosion may occur on the heat transfer surface due to the molten salt contained in the black liquor combustion gas, especially when the wall surface temperature of the heat transfer tube is 560°C.
If the temperature exceeds this level, corrosion will progress rapidly.

Therefore, when designing a chemical recovery boiler, it is necessary to take the above points into consideration.

Furthermore, if the heat transfer tubes are damaged due to the corrosion mentioned above and water enters the smelt, an explosion may occur and is extremely dangerous, so corrosion issues must be given top priority in chemical recovery boilers. There is.

First, the outline of the chemical recovery boiler will be explained using FIG. In the figure, the black liquor supplied into the furnace 1 through the spray gun 5 is dried in the furnace 1', accumulated as charbet, and burned.

The heat exchanger in the black liquor is reduced to smelt by this smelt, and N82S and Na2CO3 are recovered outside the furnace.

On the other hand, the combustion gas in the char bed 6 is in the furnace l.

Through the superheater 2, the contact heat transfer surface 3, and the economizers 4, 4',
Work 2 is discharged. During this flow process, the heat retained in the combustion gas is recovered.

That is, the water supplied from the water supply pump 'l into the economizers 4, 4' (J) is heated by n and enters the upper drum 8.The water that enters the upper drum 8 is As it descends through the numerous heat transfer tubes that make up the surface 3, it is further heated up and reaches the lower drum 8', then descends through the downcomer pipe 13 and flows into the bottom of the furnace 1'. The high-temperature water that flowed into furnace 1
' into the water pipe that makes up the peripheral wall of the char bed 6.
Mixing of saturated water and steam The steam of the mixed water that has flowed into the upper drum 8 in this way is led to the 3F & heat storage header 9, where it is further heated in the superheater. The temperature is raised and collected in the superheater outlet header 10, and as high-temperature steam, the main steam g11 is guided to a steam turbine (not shown) to generate electricity.

Meanwhile, the saturated water flows into the contact heating surface 3 again.

Here, there is a concern about the aforementioned high temperature TfE corrosion at the outlet of the superheater 2, which is the highest temperature section, and for this reason, the temperature of the steam taken out from the main steam pipe 11 is limited, and the high temperature steam is
I couldn't do it.

As described above, in Papermaking Gran 1, the boiler corrosion problem becomes a major gap wall, and only steam at a constant temperature can be obtained.

However, due to recent technical advances in energy conservation in P paper plants, the use of steam within the plant has progressed, and as a result, highly efficient power generation plants that can generate a high amount of power with the same evaporator are now available. became. To achieve this, it is necessary to generate high-temperature steam with a higher enthalpy than in the past, and the present invention was developed in view of the above-mentioned interest.

The present invention provides a power generation plant for a paper manufacturing plant that improves reliability against boiler corrosion, generates high-temperature steam, and generates the amount of power necessary for the paper manufacturing plant.

That is, the present invention provides a chemical recovery boiler and an independent superheater, etc., and the chemical recovery boiler generates 1 ton of steam that is sufficiently protected against corrosion, and this steam is transferred to an independent superheater or other steam generator. It is characterized in that it is guided to a facility to make steam at a desired temperature, and then guided to a steam turbine.

One embodiment will be described in detail below.

In Figure 2, ■ is a chemical recovery boiler, 2 is a superheater for the chemical recovery boiler, and 014 is an independent superheater that further increases the temperature of the steam from superheater 2 to obtain high-temperature steam. , the heat source is, for example, heavy oil combustion. 15 is a steam turbine, 16 is a condenser, and 7 is a water pump.

In this embodiment, the temperature of the main air is adjusted and the chemical recovery boiler 1 is operated so that the wall temperature of the superheater 2 is 560° C. or less.

For example, by operating the chemical recovery boiler 1 so that the temperature of the main air becomes 480°C, it is ensured that the tube wall temperature of the superheater 2 is 5 (30'C) or less.

Next, this main non-air is led to an independent superheater 14, and is supplied to the steam turbine as an I-air at a desired temperature, for example, 550°C.

This independent heating bone 14 uses an entirely separate heat source, so there are no corrosion problems, and there is no risk of explosion due to water-smelt reactions.

In this way, the steam that has been generated by the steam turbine 15 is condensed in the condenser 16 and supplied to the chemical recovery boiler 1 by the feed water pump 7.

As described in detail above, according to the present invention, the temperature of the steam generated from the chemical recovery boiler is suppressed by providing a superheater independent of the chemical recovery boiler, thereby ensuring that the wall surface temperature of the heat exchanger tube is at a temperature that does not corrode. It was possible to prevent the risk of explosion due to corrosion and improve the reliability of the entire paper manufacturing plant to a large rfs. Furthermore, the independent superheater allows the temperature of the steam to be set arbitrarily, and the steam at the temperature required by the paper manufacturing plant can be supplied.

in this way? ′! The reliability of the paper plant and the power generation efficiency have been improved at the same time, and the effectiveness of the paper plant as a power generation plant is remarkable.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram schematically showing a medicine recovery wheel. FIG. 2 is a positive system diagram showing an embodiment of the present invention. 1... Chemical boiler 2... Superheater 14...
・Independent superheater 2 x 1 unit

Claims (1)

[Claims] (1) A chemical recovery boiler and independent superheated natural gas generation equipment are installed, and the chemical recovery boiler generates only relatively low-temperature steam, and this steam is guided to an independent superheater or other steam generation equipment. A power generation plant in a paper manufacturing plant characterized in that the steam is converted into desired high temperature steam and this steam is supplied to a steam turbine.