# US 10,478,774 B2 · Denitrator

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- Number: US 10,478,774 B2
- Document ID: US10478774B2
- Status: Granted
- Kind: B2
- Application number: 16/065,697
- Filed: 2016-11-11
- Published: 2018-12-27
- Granted: 2019-11-19
- Earliest claimed: 2015-12-25
- Assignees: Mitsubishi Heavy Industries, Ltd.
- Applicants: Mitsubishi Heavy Industries, Ltd.
- Inventors: Keiichi Nakagawa; Mikiya Sakurai; Kiyoto Itakura; Hitoshi Tokunaga; Naoya Okuzumi; Hirokazu Tsutsumi
- Web page: https://patentgrep.com/patent/US10478774B2

## CPC

- B01D 53/56: Nitrogen oxides (B01D53/60 takes precedence)
- B01D 53/76: Gas phase processes, e.g. by using aerosols
- F23J 15/00: Arrangements of devices for treating smoke or fumes
- F23J 15/003: {for supplying chemicals to fumes, e.g. using injection devices}
- F23J 15/006: {Layout of treatment plant}
- B01D 2251/2062: Ammonia
- B01D 2257/404: Nitrogen oxides other than dinitrogen oxide
- B01D 2258/0283: Flue gases
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- F23J: REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES (combustion apparatus for consuming smoke or fumes, e.g. exhaust gases, F23G7/06)

## Abstract

A denitrator removes nitrogen oxide in a flue gas generated from a combustion furnace by injecting a reducing agent into the flue gas. The denitrator includes a housing disposed above the combustion furnace. The housing includes a discharge port for the flue gas at one end of the housing. A cross-sectional area of flow of the flue gas gradually increases toward the discharge port. The housing gathers and guides the flue gas to the discharge port. The denitrator injects the reducing agent in another end of the housing.

## Claims

### Claim 1

A denitrator for removing nitrogen oxide in flue gas generated from a combustion furnace by injecting a reducing agent into the flue gas, the denitrator comprising:
a housing disposed above the combustion furnace,
wherein the housing comprises a discharge port for the flue gas at one end of the housing,
wherein a cross-sectional area of flow of the flue gas gradually increases toward the discharge port,
wherein the housing gathers and guides the flue gas to the discharge port,
wherein the denitrator injects the reducing agent into another end of the housing, and
wherein the housing comprises a ceiling that is inclined downward from the one end toward the another end.

### Claim 2 (depends on 1)

The denitrator according to claim 1,
wherein the reducing agent comprises ammonia gas, and
wherein the denitrator injects the ammonia gas into the flue gas, and
wherein, when the flue gas has a temperature of at least 1000° C., the ammonia gas relative to a flow rate of the flue gas is not more than 0.1 vol %, or in a range of 0.01 to 0.06 vol %.

### Claim 3 (depends on 2)

The denitrator according to claim 2, wherein
the denitrator injects the ammonia gas into the flue gas in a first region on the another end that accounts for at most 50% of the flue gas in the housing, and
at least 50% of the ammonia gas is injected in a second region on the another end that accounts for at most 30% of the flue gas in the housing.

### Claim 4 (depends on 3)

The denitrator according to claim 3, wherein a flow velocity of injecting the ammonia gas is in a range from 100 to 2000 Nm/s.

### Claim 5 (depends on 4)

The denitrator according to claim 4, wherein the denitrator injects nitrogen simultaneously with and from the same position as the ammonia gas.

### Claim 6 (depends on 5)

The denitrator according to claim 5, wherein an amount of supply of the nitrogen is 0.1 to 5 times as large as an amount of supply of the ammonia gas.