JP2000074331A - Method for improving overall thermal efficiency by exhaust gas temperature elevating of thermal storage burner system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To largely improve an overall thermal efficiency by effectively utilizing a sensible heat of an exhaust gas. SOLUTION: In the thermal storage burner system for exhausting burned exhaust gas 21 from a burner B1 or B2 through a thermal storage unit R1 or R2 at time of non-burning by switching paired two burners B1, B2 at the each predetermined time, for alternately burning the burners B1, B2, and for supplying combustion air 12 to the burner B1 or B2 via the unit R1 or R2 at the time of burning; the gas 21 is elevated at its temperature, thermally converting a sensible heat absorbed via the unit R1 or R2 of the gas into steam at a serial two stages to be recovered, driving a blower 30 of the air by steam heat recovered at a high temperature stage, driving a regenerator 25 of dehumidified liquid by the steam heat recovered at a low temperature stage, and dehumidifying combustion gas 18 and/or the air 12 by using the dehumidified liquid regenerated by the regenerator.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for improving the overall thermal efficiency of a heat storage burner system in which fuel gas and combustion air are supplied to a burner and burned by raising the temperature of exhaust gas.

[0002]

2. Description of the Related Art Conventionally, two burners forming a pair are switched alternately at predetermined time intervals and burned alternately. Combustion air is supplied to the burner through a heat storage during combustion, and combustion is performed from the burner through a heat storage during non-combustion. A heat storage burner system for discharging exhaust gas is disclosed in Japanese Patent Application Laid-Open No. 6-200321 and is a known technology.

[0003]

In a conventional heat storage burner system used as a steel heating furnace or the like, exhaust gas having sensible heat (about 250 ° C.) sucked through a heat storage body is released without being used. SUMMARY OF THE INVENTION It is an object of the present invention to provide a heat storage burner system capable of significantly improving the overall thermal efficiency of a system by effectively utilizing the sensible heat of exhaust gas, and simultaneously increasing the efficiency of a combustion system by using recovered heat. It is an object of the present invention to provide a method for improving overall thermal efficiency by increasing the temperature of exhaust gas.

[0004]

In order to achieve the above object, a method for improving the overall thermal efficiency by increasing the temperature of exhaust gas in a heat storage burner system according to claim 1 of the present invention, comprises the steps of: Switch and burn alternately,
In a heat storage burner system that supplies combustion air to the burner through the heat storage during combustion and discharges combustion exhaust gas from the burner through the heat storage during non-combustion, the temperature of the exhaust gas is increased, and the exhaust gas is suctioned through the heat storage. The sensible heat is converted into steam in two stages in series and collected.The steam heat collected in the high-temperature stage drives the combustion air blower, and the steam heat collected in the low-temperature stage forms a dehumidifier regenerator. The fuel cell system is driven to dehumidify the fuel gas and / or combustion air using the dehumidified liquid regenerated by the dehumidified liquid regenerator.

According to a second aspect of the present invention, two burners forming a pair are alternately burned by switching at predetermined intervals, and combustion air is supplied to the burner through a heat storage during combustion, and combustion is performed during non-combustion. In a heat storage burner system for discharging combustion exhaust gas from the burner through a heat storage material, the exhaust gas is heated to a high temperature, and the sensible heat sucked through the heat storage material of the exhaust gas is converted into steam in two stages in series and collected. The steam heat recovered in the stage drives the combustion air blower and preheats the fuel gas and / or combustion air, and the steam heat recovered in the low-temperature stage drives the dehumidifier regenerator. The fuel gas and / or combustion air is dehumidified by using the dehumidified liquid regenerated by the liquid regenerator.

As described above, in the present invention, the exhaust gas of the heat storage bar system is heated to a high temperature, and the steam recovered from the high temperature exhaust gas at two temperature levels is used to drive the blower driving power of the combustion air, the fuel gas and / or the combustion gas. Air preheating heat source,
Since it is used as a heat source for dehumidifying and regenerating fuel gas and / or combustion air, the final temperature of exhaust gas can be reduced to the return temperature level of the dehumidifying regenerator, and the overall heat utilization efficiency is greatly improved. In addition, the efficiency of the combustion system can be increased at the same time by reducing the preheating and the driving energy.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments shown in the drawings. This embodiment is a slab,
This shows an application example in which a hot blast stove for heating pipes and the like is used as a heat storage burner system. In the drawing, a burner B1 for injecting a flame 7 is in a combustion state, and a combustion exhaust gas 21 is a non-combustion side burner B2, a heat storage element. R2, combustion exhaust valve V4
Has been exhausted through.

In this state, the valve V1 of the fuel gas 18, the valve V4 of the combustion exhaust gas 18 and the bubble V5 of the combustion air 12 are opened, and the valve V2 of the fuel gas 18 and the combustion exhaust gas 18 are opened.
The valve V2 and the bubble V6 of the combustion air 12 are closed.

The combustion in the burner B1 continues for a time set by a controller or the like. When the combustion switching time is reached, the valves V1, V4 and V5 are closed, and the valves V2, V3 and V6 are closed. Opened, burner B2
Can be switched to combustion.

As described above, in the combustion system according to the present embodiment, the two burners B1 and B2 forming a pair are switched at predetermined time intervals and burned alternately. At the time of combustion, the burners B1 and B2 pass through the heat accumulator R1 or R2. The combustion air 12 is supplied to the burner B1 or B2.
Or flue gas 2 from B1 through regenerator R2 or R1
1 is a regenerative burner system which discharges the exhaust gas 21 at a conventional set temperature (for example, 250 ° C.).
℃) to a higher temperature (for example, 300 ℃).

A heat exchanger 2 for converting the sensible heat sucked into the exhaust gas 21 through the heat storage material R2 or R1 of the exhaust gas 21 into steam in two stages in series and recovering it.
2, the steam-operated blower 30 for combustion air is driven by the steam heat of about 180 ° C. collected in the high-temperature stage 22a of the heat exchanger 22, and the preheater 28 for fuel gas and combustion air is operated. The fuel gas 18 and the combustion air 12
Perform preheating.

The dehumidifying liquid regenerator 25 is heated by the steam heat of about 120 ° C. recovered in the low-temperature stage 22b of the heat exchanger 22.
And the circulation lines 25a and 25b are connected to a dehumidifier 26 incorporated in the fuel gas supply path 18a and a dehumidifier 27 incorporated in the combustion air supply path 12a by using the dehumidified liquid regenerated by the dehumidified liquid regenerator 25. The combustion air 12 and the fuel gas 18 containing moisture are dehumidified by being circulated.

The high-temperature steam circulation path and the low-temperature steam circulation path of the heat exchanger 22 have a steam circulation pump 23.
a and 23b are incorporated. The dehumidifier 26, 27
Moves the moisture from the fuel gas 18 and the combustion air 12 to the dehumidifying solution by directly contacting the fuel gas 18 containing the moisture and the combustion air 12 with a high concentration and low temperature lithium chloride solution (dehumidifying solution). The dehumidifying solution, which is conventionally known to be dehumidified by the dehumidifying method, is circulated and transferred to the dehumidifying solution regenerator 25 to be heated, and is brought into direct contact with the atmosphere to remove moisture from the dehumidifying solution into the air. It is moved and concentrated and regenerated to a high concentration.

In the embodiment described above, since the final temperature of the exhaust gas 21 can be lowered to the level of 100 ° C., the heat of the temperature difference (corresponding to about 150 ° C.) due to the high temperature can be effectively used, and the recovered heat can be preheated. The overall thermal efficiency of the system is greatly improved. Further, by using the recovered heat to dehumidify the combustion air and fuel gas and drive the blower 30, the thermal efficiency of the burner system can be increased.

Although the above embodiment has been described with respect to the case where both the fuel gas 18 and the combustion air 12 are dehumidified and preheated, either the combustion air 12 or the fuel gas 18 is dehumidified and preheated. The preheater 28 may be omitted as shown in claim 1.

[0016]

As described above, according to the method of the present invention, the total thermal efficiency of the system can be significantly improved by effectively utilizing the sensible heat of the exhaust gas, and the recovered heat can be used. This has the effect of increasing the efficiency of the combustion system at the same time.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of a method for improving overall thermal efficiency by increasing the temperature of exhaust gas in a heat storage burner system according to the present invention.

[Explanation of symbols]

7: Flame, 12: Combustion air, 12a: Combustion air supply path, 18: Fuel gas, 18a: Fuel gas supply path, 21: Combustion exhaust gas, B1, B2: Burner, R1, R
2: heat storage element, V1, V2: fuel gas valve, V3, V
4: Valve of combustion exhaust gas, V5, V6: Valve of combustion air, 22: Heat exchanger, 25: Dehumidified liquid regenerator, 26, 2
7 ... dehumidifier, 28 ... preheater, 30 ... blower.

Claims (2)

[Claims] 1. A pair of two burners are switched at predetermined time intervals and burned alternately, and combustion air is supplied to the burner through a regenerator during combustion, and combustion exhaust gas is passed through the regenerator from the burner during non-combustion. In the heat storage burner system to be discharged, the exhaust gas is heated to a high temperature, and the sensible heat sucked through the heat storage body of the exhaust gas is converted into steam in two stages in series and collected, and is burned by the steam heat collected in the high temperature stage The dehumidifier regenerator is driven by the steam heat recovered in the low-temperature stage, and the dehumidifier regenerated by the dehumidifier regenerator is used to dehumidify the fuel gas and / or combustion air. A method for improving the overall thermal efficiency by increasing the temperature of exhaust gas in a heat storage burner system. 2. A pair of two burners are switched at predetermined time intervals and burned alternately. During combustion, combustion air is supplied to the burner through a regenerator, and during non-combustion, combustion exhaust gas is passed from the burner through a regenerator. In the heat storage burner system to be discharged, the exhaust gas is heated to a high temperature, and the sensible heat sucked through the heat storage body of the exhaust gas is converted into steam in two stages in series and collected, and is burned by the steam heat collected in the high temperature stage Drives the air blower and preheats the fuel gas and / or combustion air, drives the dehumidifier regenerator with the steam heat recovered at the low temperature stage, and regenerates the dehumidifier with this dehumidifier regenerator. A method for improving the overall thermal efficiency of a heat storage burner system by increasing the temperature of exhaust gas, wherein dehumidification of fuel gas and / or combustion air is performed using the gas.