KR20050000905A - Apparatus for reducing corrosion of a pipe in a regenerative combustion system - Google Patents

Abstract

PURPOSE: A pipe corrosion preventing device is provided to prevent the obstruction of a system operation by preventing the corrosion of a pipe and the increase of pressure. CONSTITUTION: Bypass pipes(9a,9b) to form a passage of combustion exhaust gas in a main pipe(11) are formed between regenerative burners(5a,5b) and regenerators(6a,6b). Isolation valves(10a,10b) are installed in the bypass pipes. The formation of the air passage through the bypass pipes are controlled by opening or closing the isolation valves. The solidification of a reed, the cryogenic corrosion and the condensation of moisture are suppressed by discharging the part of the hot combustion exhaust gas without passing through the regenerators and increasing the temperature of the cryogenic exhaust gas.

Description

Apparatus for reducing corrosion of a pipe in a regenerative combustion system}

The present invention relates to a combustion system using a regenerative burner, and more particularly, by installing a bypass pipe for exhaust gas exhaust between a burner and a regenerator of a regenerative combustion system. The present invention relates to a pipe corrosion prevention device of a regenerative combustion system capable of preventing a low temperature corrosion of the heat accumulator.

In a combustion system using a conventional regenerative burner, as illustrated in FIG. 1, burners 5a and 5b are installed at both sides of the combustion furnace 4, respectively, and a heat accumulator for supplying combustion air to each burner. 6a and 6b are connected to each other, and each of the burners 5 is connected to a fuel pipe provided with shutoff valves 7a and 7b, and each of the heat accumulators 6a and 6b connects the main pipe 11 to each other. It is connected to the four sides of the combustion exhaust gas outlet (8a) and the combustion air inlet (8b) is formed through the flow path for the blowing of the combustion air (2) or the discharge of the combustion exhaust gas (3) can be selectively Is configured.

The main feature of this regenerative combustion system is that one of the two burners installed on both sides of the furnace is operated as a combustion burner supplied with fuel / air and the other burner is produced by a forced draft fan. It operates as an exhaust port passage where combustion flue gas is sucked in, and the operation method is alternately performed at regular intervals, and the respective shift operation and the switching are performed through the shutoff valves 7a and 7b and the four sides 8 and the like. .

The regenerative combustion system includes a heat accumulator, and the heat accumulators 6a and 6b to which the combustion exhaust gas 3 is exhausted and the combustion air 2 is supplied are connected to and installed by flanges, respectively. The heat accumulator recovers sensible heat of the combustion flue gas when the combustion flue gas of high temperature passes and uses it to preheat the combustion air. In other words, in the regenerative combustion system, the regenerator is an important facility that maximizes the thermal efficiency of the system by directly recovering the arrangement of the hot exhaust gas.

The heat accumulators loaded in the heat accumulators 6a and 6b have many applications of spherical and honeycomb types, and the combustion exhaust gas temperature distribution A1 and the combustion air temperature distribution A2 in the heat accumulator in the normal state are the shafts. It is distributed as shown in the graph of FIG. 2 with respect to the axial length of the heat | fever 6a, 6b. That is, as can be seen in Figure 2, the heat accumulator (6a, 6b) is supplied with a high temperature combustion exhaust gas is discharged to a low temperature, the air of the atmospheric temperature is preheated through the heat accumulator is supplied to the burner at a high temperature.

However, in the early stage of operation, even if the hot combustion flue gas is supplied, the temperature drops rapidly below 100 [ ^° C] in the low atmospheric temperature regenerator, and consequently, a considerable amount of moisture in the flue gas is condensed. At this time, if sulfur-containing fuel / oxidant is used, the sulfur component to be included in the combustion flue gas is solidified may be attached to the pipe and cause corrosion of the pipe.

In the case of using a fuel mainly composed of COG (Coke Oven Gas), which is a by-product gas of the steelmaking process, a low temperature corrosion of sulfur causes increased pressure loss in the pipe and weakening of the pipe. Accordingly, the heat accumulator is designed to exhaust the combustion flue gas to a temperature of 200 [ ^° C.] or more during normal operation, but it has a limitation that a considerable amount of sulfur can solidify at the beginning of the regenerative combustion system.

Therefore, the present invention has been made to solve the above problems, the present invention is a low temperature phenomenon in the initial stage and the rear stage of the regenerator when the sulfur-containing fuel is used in the regenerative burner system to which the regenerative combustion system is applied The purpose of the present invention is to provide a pipe corrosion prevention device in a regenerative combustion system that can remove a phenomenon that impedes the operation of the system by causing sulfur corrosion and causing pipe corrosion and increased pressure loss.

1 is a configuration diagram of a regenerative combustion system according to the prior art

2 is a temperature distribution diagram of the regenerator combustion system according to FIG.

3 is a block diagram of a pipe corrosion prevention apparatus of a regenerative combustion system according to an embodiment of the present invention.

1 fuel 2 combustion air

3: combustion flue gas 4: combustion furnace

5a, 5b: Regenerative burner 6a, 6b: Regenerative

7a, 7b, 10a, 10b: Shut-off valve 8: 4-way valve

8a: combustion exhaust gas outlet 8b: combustion air inlet

9a, 9b: bypass piping 11: main piping

A1: combustion exhaust gas temperature distribution line A2: combustion air temperature distribution line

In order to achieve the above object, the present invention provides a regenerative combustion system in which a bypass pipe is installed in a main pipe between a regenerative burner and a regenerator in order to prevent low-temperature corrosion of the piping by sulfur when using fuel / air containing sulfur in a regenerative burner system. Providing corrosion protection for piping in the system.

Pipe corrosion prevention apparatus according to an embodiment of the present invention may be configured to control the flow path formed by the bypass pipe by opening and closing the shut-off valve by installing a shut-off valve in the bypass pipe.

The objects, features and advantages of the present invention will be more readily understood by reference to the accompanying drawings and the following detailed description.

Hereinafter, the configuration and operation of the present invention with reference to the accompanying drawings in detail as follows.

3 is a configuration diagram of a pipe corrosion prevention device in a regenerative combustion system according to an embodiment of the present invention. The present invention connects regenerative burners 5a and 5b to both combustion furnaces 4, respectively. In the combustion system configured to connect the heat accumulators 6a and 6b to the heat accumulator burners 5a and 5b, respectively, to form fuel / air flow paths by alternating operation of the two burners, the heat accumulator burners 5a and 5b. And bypass pipes 9a and 9b for forming a flow path of combustion flue gas in the main pipe 11 between the heat accumulators 6a and 6b, and a shutoff valve 10a in the bypass pipes 9a and 9b. 10b) is provided so that the formation of the air flow path by the bypass pipe can be controlled from the outside by an operation of opening or closing the shutoff valve.

As shown in FIG. 3, in the regenerative combustion system according to the present invention, two regenerative burners 5a and 5b and two regenerative heaters 6a and 6b in one combustion furnace 4 and fuel to the burner. Shut-off valves 7a and 7b for supply switching and the like are installed, and the main pipes 11 connected to the respective heat accumulators 6a and 6b from the two burners 5a and 5b, unlike ordinary heat storage burner systems. By-pass pipes 9a and 9b through which hot combustion flue gas and a part of combustion air can pass are respectively installed in the air so that a part of combustion flue gas having a predetermined temperature or less at the beginning of the operation is passed through each bypass pipe. It is possible to be discharged directly to the rear end of the heat accumulator through (9a, 9b) so as not to be lowered by the heat accumulator (6a, 6b) to solve the problems caused by the low temperature phenomenon of the combustion flue gas do.

In the present invention, between the heat storage burners (5a, 5b) and the heat storage (6a, 6b) through which the high-temperature combustion exhaust gas passes, the main pipe (11) is wrapped with high temperature refractory, and the bypass pipe (by-pass) pipe ( 9a, 9b) also passes through the hot combustion flue-gas, so the inside of it must be protected with refractory. In addition, the bypass pipe may be about 1/5 of the diameter of the main pipe 11 for exhaust gas exhaust.

Shut-off valves 10a and 10b serving as control valves are attached to the bypass pipes 9a and 9b of the present invention. It is a butterfly valve (butterfly valve) to be made of refractory to withstand high temperatures, but it would be desirable to manufacture to protect the plate (plate).

The operation of the regenerative combustion system according to the present invention configured as abnormal light and its effects are as follows.

First, the burner 5a (the burner installed on the left side of the combustion furnace in FIG. 2 is operated as an example) to which combustion air is supplied at the initial stage of operation is closed to the corresponding shutoff valve 10a so that all the combustion air is shafted. It is preheated through the heat 6a to be supplied to the corresponding burner 5a. At this time, the burner 5b side to which the high temperature combustion exhaust gas is supplied opens the shutoff valve 10b so that a part of the high temperature combustion exhaust gas passes through the bypass pipe 9b and most of the combustion exhaust gas passes through the heat storage 6b. Do it.

They are integrated at the rear end of the regenerator and are discharged through the main pipe (11).

The exhaust gas passing through the heat accumulator 6b is designed to be discharged by lowering the temperature to about 150 [ ^o C], and the small amount of the exhaust gas passing through the bypass pipe 9b is the same as the high temperature low temperature so that they are accumulated. When integrated at the rear end of the hot air, it is possible to maintain approximately 200 [ ^° C.], thereby eliminating problems such as pipe corrosion due to the lowering of exhaust gas generated at the rear end of the initial heat storage.

Therefore, when the exhaust gas passing through the heat storage 6b is 130 [ ^o C] or more, the shutoff valve 10b is closed to suppress the movement of the high temperature exhaust gas through the bypass pipe 9b.

Of course, according to the present invention, although the preheating temperature of the air supplied to the burner is slightly lowered at the beginning of operation, when the exhaust gas temperature passing through the regenerator is 130 [ ^o C] or more, the exhaust gas passes through the bypass pipe. The overall thermal efficiency is not significantly different because it is blocked.

According to the present invention, by discharging a part of the hot combustion flue gas without passing through the regenerator, the temperature of the flue gas lowered while passing through the regenerator can be raised to suppress the solidification of sulfur, low temperature corrosion and condensation of moisture. .

In addition, the hot exhaust gas is strongly sucked through an induced draft fan (IDF), but the inlet flow rate of the hot exhaust gas into the bypass pipe having a small pressure loss may be increased to increase the overall exhaust gas suction rate.

According to the present invention, in the initial operation, although the pressure loss in the heat accumulator is small, the flow rate of exhaust gas through the bypass pipe is small, but the pressure loss in the heat accumulator increases until the steady state is reached, so the flow rate to the heat accumulator is increased. Compared to the exhaust gas flow rate through the bypass pipe can be increased. Accordingly, when the temperature of the rear end of the regenerator reaches 130 ^° C., the bypass pipe should be blocked to allow all the hot combustion exhaust gas to pass through the regenerator.

Claims (2)

The regenerative type burner system is provided with a bypass pipe for bypass of combustion flue gas in the main pipe between the regenerative burner and the regenerator in order to prevent low-temperature corrosion of the pipe by sulfur when using sulfur-containing fuel / air in the regenerative burner system. Piping corrosion prevention device in combustion system. The method of claim 1, Preventing corrosion of the pipes in the heat storage type combustion system, characterized in that by installing a shut-off valve in the bypass pipe to control the formation of the air flow path by the bypass pipe by opening and closing the shut-off valve.