JPH07265660A - Apparatus for vaporizing aqueous ammonia solution - Google Patents

Abstract

PURPOSE:To unnecessitate a waste gas fan and an ammonia soln. vaporizer and to simplify an apparatus by installing a tube for vaporizing an ammonia soln. in a waste heat recovering boiler on the upper stream side of a denitration reactor. CONSTITUTION:Many heat exchangers 11 are arranged in a waste heat recovering boiler 12 using waste gas from a gas turbine, etc., a denitration reactor 1 contg. a catalyst is interposed between the heat exchangers 11 and NOx in waste gas is reduced to harmless nitrogen and water. At this time, a meandering tube 4 for vaporizing an ammonia soln. is disposed on the upper stream side of most of the heat exchangers 11 and the reactor 1, and many ammonia injecting nozzles 5 are fixed in the rear end part of the tube 4. An ammonia soln. allowed to flow in the tube 4 is gradually heated by heat exchange with waste gas on the outside of the tube 4, the concn. rises and the ammonia soln. is converted into gaseous ammonia and steam by vaporization. The gaseous ammonia and steam spout out of the nozzles 5 and are introduced into the reactor 1 after mixing with the waste gas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ammonia water vaporizer for denitration of exhaust gas.

[0002]

2. Description of the Related Art A conventional ammonia water vaporizer for exhaust gas denitration will be described with reference to FIG. In order to vaporize the ammonia water, a separately installed ammonia water vaporizer 6 is installed, and a medium for atomizing the ammonia water and the ammonia water are mixed and sprayed from the atomizing nozzle 8 into the ammonia water vaporizer 6; Ammonia injection nozzle 5 is vaporized by vaporizing in a part of the exhaust gas branched from the exhaust gas guided to the denitration reactor 1.
Since it is injected from above, an exhaust gas fan 7, a separate ammonia water vaporizer 6 and the like are required. In addition, in FIG. 5, 9 shows an ammonia water tank, and 10 shows an ammonia water pump.

[0003]

As described above, in the conventional method, in order to vaporize the ammonia water, it is first mixed with the atomizing medium so as to be easily vaporized and then sprayed as small ammonia water droplets. The ammonia droplets thus formed are heated to be vaporized. In that case, as a heat source, it is necessary to install an exhaust gas fan for extracting exhaust gas from an exhaust gas system and a separate ammonia water vaporizer equipped with an atomizing nozzle, which causes a problem that the system is complicated. In view of the above technical level, the present invention aims to provide a denitration ammonia water vaporizer capable of solving the problems of the prior art.

[0004]

According to the present invention, an ammonia water vaporization tube is installed inside the exhaust heat recovery boiler located upstream of the denitration reactor, inside the exhaust gas duct, or inside the flue of the heat transfer section at the rear of the boiler. Is an ammonia water vaporizer for exhaust gas denitration equipment.

[0005]

The operation of the present invention will be described with reference to FIG. As shown in FIG. 4, the ammonia water flowing in the ammonia water vaporizing tube 4 exchanges heat with the exhaust gas flowing outside the tube 4, is gradually heated, and the concentration is increased to vaporize into ammonia gas and water vapor, It is ejected from the ammonia injection nozzle 5 and mixed with the exhaust gas to be introduced into the denitration reactor 1 (not shown).

[0006]

EXAMPLES The effects of the present invention will be clarified below with reference to specific examples of the present invention. (Embodiment 1) A first embodiment of the present invention will be described with reference to FIG. This embodiment is applied to an exhaust heat recovery boiler 12 using exhaust gas from a gas turbine, a diesel engine or the like (not shown), and a large number of heat exchangers (heat transfer tubes) are provided in the exhaust heat recovery boiler 12. ) 11 are arranged, and a denitration reactor 1 using a catalyst is provided between them, and nitrogen oxide in exhaust gas is injected into the ammonia gas to reduce harmless nitrogen and water. . A meandering ammonia water vaporization tube 4 is provided upstream of the heat exchanger 11 and the denitration reactor 1, and a large number of ammonia injection nozzles 5 are provided at the final end. To the vaporizing tube 4, the ammonia water tank 9 that stores ammonia water (or urea water) at room temperature raises the pressure with the ammonia water pump 10 and adjusts the flow rate with the adjusting valve 13, while introducing the introducing pipe 14 into the vaporizing tube 4. Introduce through. Ammonia water is pressurized from the ammonia water tank 9 at room temperature by the ammonia water pump 10, and
Exhaust heat recovery boiler 1 while adjusting the flow rate with the flow rate adjusting valve 13.
Flow to the ammonia water vaporization tube 4 installed in 2
After vaporization, it is injected through the ammonia injection nozzle 5.

(Second Embodiment) FIG. 2 shows a second embodiment of the present invention.
This will be described with reference to (a) and (b). This embodiment is provided in the exhaust gas duct 2 of the boiler (Fig. 2 (a)) or in the exhaust gas duct 2 of the gas turbine (Fig. 2 (b)). A denitration reactor 1 using a catalyst is provided, and nitrogen oxide in exhaust gas is reduced to harmless nitrogen and water by injecting ammonia gas. The meandering ammonia water vaporization tube 4 is provided upstream of the denitration reactor 1, and a large number of ammonia injection nozzles 5 for ejecting ammonia gas are provided at the final end of the exhaust gas duct. Note that the introduction system of the ammonia water is the same as that of the first embodiment, and therefore the description thereof is omitted.

(Embodiment 3) Next, a third embodiment of the present invention will be described with reference to FIG. In this example, the rear flue 3 of the boiler is used.
A tube 4 for vaporizing ammonia water is installed inside. Since a large number of heat transfer tubes 11 are provided in the rear flue 3 of the boiler, the ammonia water vaporization tube 4 is provided in the middle of the heat transfer tube 11, and the exhaust gas duct 2 connected to the tube 4 is provided. A denitration reactor 1 is provided. Note that the introduction system of the ammonia water is the same as that of the first embodiment, and therefore the description thereof is omitted.

[0009]

According to the present invention, the ammonia water vaporization tube can be easily installed in the exhaust heat recovery boiler in which the exhaust gas guided to the denitration reactor flows, or in the exhaust gas duct or in the heat transfer section flue at the rear of the boiler. Yes, the system is simple, no exhaust gas fan or separate ammonia water vaporizer is required, and the complexity of the device as in the conventional method is improved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an application example of the present invention to an exhaust heat recovery boiler.

FIG. 2 is an explanatory diagram of an application example of the present invention to a gas duct.

FIG. 3 is an explanatory diagram of an application example of the present invention to a boiler.

FIG. 4 is an explanatory view of the action of the ammonia water vaporizer of the present invention.

FIG. 5 is an explanatory view of one mode of a conventional ammonia water vaporizer.

Claims (1)

[Claims] 1. An exhaust gas denitration apparatus comprising an ammonia water vaporization tube installed inside an exhaust heat recovery boiler located upstream of a denitration reactor, inside an exhaust gas duct, or inside a flue of a heat transfer section at a rear portion of the boiler. Ammonia water vaporizer.