JPS5930999B2 - Water washing device for heat transfer surfaces - Google Patents

Description

[Detailed description of the invention] The present invention relates to a water washing device for heat transfer surfaces of boilers and the like.

In various parts of boiler furnaces that burn heavy oil, crude oil, and residual oil from petroleum plants, there are deposits (mainly composed of fuel ash).
It is known that deposits (hereinafter referred to as "deposits") accumulate and cause various problems as shown below.

(1) A large amount adheres to the outer surface of the heat transfer surface in the boiler furnace, inhibiting heat transfer.

(2) As a result, the exhaust gas temperature increases, which adversely affects equipment in the gas flow path.

(3) Deposits are generally highly corrosive to metals (and corrode heat transfer surfaces).

(4) If there is a large amount of deposits, it will narrow the exhaust gas flow path, making combustion itself difficult and hindering the normal operation of the boiler.

As shown in Table 1, even in the same boiler, the properties of deposits vary depending on where they are deposited, not only in chemical composition but also in physical properties such as hardness and adhesion to heat exchanger tubes. There is a lot of vanadium V, which is hard, but there is less vanadium at low temperatures, and the hydrogen ion concentration of the eluted water (
(hereinafter referred to as PH) tends to be low (acidic).

That is, when sulfur S is contained in the fuel, it is oxidized during combustion, and a part of it becomes sulfuric acid H2SO4, which is contained in the fuel ash and exhibits acidity.

Also, since sulfuric acid tends to condense in low-temperature areas, deposits in low-temperature areas become highly acidic.

S102→S02 1 SO2+-〇2→SO3 S03+H20→H2SO4 To deal with the above-mentioned problems, deposits on the high-temperature pipes are removed using hammers, sandblasting, etc. during shutdown, but this requires a large amount of human labor. However, not only is the work environment significantly deteriorated due to the large amount of noise and dust, but in the latter case, there are still problems when removing used sand as waste. Complete removal is not possible.

In addition, the deposits on low-temperature tubes such as those used in energy savers are soft, but the heat transfer area is large, and the range that human power can reach is limited due to their structure, so they cannot be removed using methods such as those used on high-temperature tubes. I can't.

For this reason, recently, attention has been paid to the relatively large amount of water-soluble components contained in the deposits, and cleaning of the heat transfer surface surface by washing with water has been carried out with extremely good results.

As is clear from Table 1, the deposits contain a very wide variety of elements, but there are surprisingly many water-soluble components (if moisture is present, the solution is likely to be removed from the heat transfer surface). .

However, if you simply drain water with a rubber hose, etc., the inside of the boiler furnace will be flooded with water, which is difficult to drain, and the leached water is highly acidic, so be careful not to stagnate or locally condense the boiler. There is a risk of corroding the material, so although various measures have been taken during actual work, the sprinkling and spraying of washing water is mainly done manually.

However, carrying out the process in a narrow boiler furnace is not only dangerous in terms of health and safety, but also has the drawback of being extremely inefficient.

The purpose of the present invention is to provide a device that can automate the above-mentioned washing removal work of deposits and perform the work efficiently and safely. The present invention is equipped with a nozzle pipe and a joint pipe which is a cross-shaped branch passage and connects the nozzle pipe to form a lattice-shaped pipe.

This case has the following advantages.

(1) Sprinkling (spraying) water onto the heat transfer surface to be washed with water is performed using piping having one or more nozzles, and the number of piping can be easily increased or decreased depending on the width of the heat transfer surface.

(2) Piping can be easily assembled and dismantled inside the furnace.

(3) Since the water washing work is automatically carried out through piping, there is no need for workers to enter the furnace, which improves the work environment and improves work efficiency, resulting in a reduction in work time.

(4) The water spray (injection) range can be changed by changing the pipe length and water supply pressure.

(5) Post-processing after water washing (spraying of Ca(OH)z solution, air blowing, etc.) can also be performed using these piping as they are.

The present invention can be widely applied to boilers, heating furnaces, garbage incinerators, etc.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory diagram showing the entire flushing device according to one embodiment of the present invention, FIG. 2a is an explanatory diagram showing an enlarged main part of the flushing device in FIG. FIG. 2C is a plan view of FIG.

This example belongs to the low-temperature section tube in the heat transfer surface of the boiler, has a larger heat transfer area than other tubes, is more likely to be inhibited by heat transfer due to deposits, and is highly adhesive to fuel. A case will be shown in which the device according to the present invention is installed in an economizer to which a large amount of ash adheres.

In the figure, an impermeable sheet (made of vinyl chloride in this example) is placed on the lower side of the economizer 1 to be flushed, and a flushing water receiving tank 2 is provided.
is installed.

The washing device includes a nozzle 3 that sprays washing water, a nozzle pipe 4, a joint pipe 5, a water supply pipe 6, a nozzle holder 7, a flow meter 8, a pressure gauge 9, a water supply pump 10 whose discharge pressure can be freely changed, and a chemical injection. It consists of a pump 11 and a valve 12.

The nozzle 3, nozzle pipe 4, and joint pipe 5 are installed on the upper and lower parts of the economizer 1 by nozzle part holders 7, and the water supply pipe 6
It is connected to equipment outside the furnace through an upper manhole 13 and a lower manhole 14.

Nozzles 3 for spraying washing water are attached to the nozzle pipe 4 at regular intervals.

Further, the joint pipe 5 is branched in four directions as shown in Fig. 2, and the nozzle pipe 4 or the plug 15 can be screwed into the joint pipe 5, and the nozzle pipe 4 or the plug 15 can be attached to the joint pipe 5 in the same way as the nozzle pipe 4. 3 (see Figure 2C).

The flushing water receiving tank 2 is equipped with a drainage pump 16, and the water is discharged from the lower manhole 14 to the outside of the furnace through a drainage pipe 17, a flow meter 18, and a PH meter 19.

In addition, D is a flushing water inlet, and E is a combustion chamber.

The functions and benefits of the above configuration will be described.

Additives B such as inhibitors are washed with water using the chemical injection pump 11.
Washing water A added with
Water is supplied to the nozzle 3 installed at the top, and the process begins by spraying washing water.

Note that the washing range can be freely determined by the joint pipe 5 and the nozzle pipe 4 according to the size of the economizer 1.

Furthermore, since the pressure of the washing water can be freely changed, the spraying range of the washing water from each nozzle 3 is extremely wide, and the entire upper surface of the economizer 1 can be sprayed.

The washing water flows down from the upper surface of the energy saver 1 to the washing water receiving tank 2 while dissolving and peeling off deposits.

The flush water stored in the flush water receiving tank 2 is discharged outside the furnace by the drain pump 16 through the drain pipe 17, the flow meter 18, and the PH meter 19.
and the chemical injection pump 11, the amount of flushing water and the amount of chemical injection can be increased or decreased depending on the washing situation.

Further, as the water washing progresses, the nozzle 3 installed at the bottom of the economizer 1 cleans the bottom surface of the economizer 1 as well as the top surface.

When the boiler is operated after washing the outer surface of the economizer 1 with water through the above operations, the exhaust gas temperature at the exit of the economizer 1 will drop by approximately 70°C compared to before washing, and the gas will adhere to the heat transfer surface. Experiments have revealed that the fuel ash that had been present has been completely removed, and that heat recovery has returned to the boiler's initial performance level.

In addition, the only work that the workers had to do inside the furnace was to inspect the 11 units when they were assembled and when they were finished, resulting in a significant reduction in personnel costs and an improvement in the working environment.

Furthermore, the washing time is approximately 1/2 compared to hand washing.
It was possible to shorten the time by 1/3, and even considering the equipment assembly time, the entire cleaning period (preliminary investigation - washing - post-treatment) was shortened.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the entire apparatus of one embodiment of the present invention, FIG. 2 a is an explanatory diagram showing an enlarged main part of the apparatus in FIG. 1, and FIG. 2 is a plan view of FIG. 2 a. FIG. 2C is a view taken along arrow a in FIG. 2a. 1... Energy saver, 2... Rinsing water tank, 3
...Nozzle, 4...Nozzle pipe, 5...
...joint pipe, 6...water supply pipe, 7...
・Nozzle part cradle, 10... Water supply pump, 11.
...Medicine injection pump, 16... Drainage pump.

Claims (1)

[Claims] 1. A water wash for a heat transfer surface, characterized by comprising a nozzle pipe provided with at least one nozzle, and a joint pipe having a cross-shaped branch passage and connecting the nozzle pipes to form a lattice-shaped pipe. Device.