# US 10,369,517 B2 · Method for controlling aerosol production during absorption in ammonia desulfurization

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- Number: US 10,369,517 B2
- Document ID: US10369517B2
- Status: Granted
- Kind: B2
- Application number: 16/232,320
- Filed: 2018-12-26
- Published: 2019-05-02
- Granted: 2019-08-06
- Earliest claimed: 2017-09-07
- Assignees: Jiangnan Environmental Protection Group Inc.
- Applicants: Jiangnan Environmental Protection Group Inc.
- Inventors: Jing Luo; Lifang Qi; Jinyong Wang
- Web page: https://patentgrep.com/patent/US10369517B2

## CPC

- B01D 53/505: {in a spray drying process}
- B01D 53/501: {by treating the gases with a solution or a suspension of an alkali or earth-alkali or ammonium compound}
- B01D 53/502: {characterised by a specific solution or suspension}
- B01D 53/504: {characterised by a specific device}
- B01D 53/75: Multi-step processes
- B01D 53/78: with gas-liquid contact
- B01D 53/96: Regeneration, reactivation or recycling of reactants
- F23J 15/04: using washing fluids {(scrubbers for removing solids only F23J15/022)}
- B01D 2251/206: Ammonium compounds
- B01D 2251/608: Sulfates
- B01D 2252/102: Ammonia
- B01D 2257/302: Sulfur oxides
- B01D 2258/0283: Flue gases
- F23J 2215/20: Sulfur; Compounds thereof
- F23J 2217/50: by cleaning fluids (washers or scrubbers)
- 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

Apparatus and methods for controlling aerosol production during absorption in ammonia desulfurization, by removing sulfur dioxide in flue gas with an absorption circulation liquid containing ammonium sulfite, so as to control the aerosol production during absorption in ammonia desulfurization. Efficient desulfurization and dust removal may be achieved by staged solution composition control and reaction condition control. At the same time ammonia escape and aerosol production during absorption may be controlled. The flue gas may be subjected to preliminary temperature lowering and purification, and may be allowed to contact with an absorption circulation liquid and a fine particle washing circulation liquid sequentially. Levels of solution compositions and reaction temperatures may be controlled.

## Claims

### Claim 1

A method for controlling aerosol production during absorption of sulfur dioxide from a flue gas, the method comprising applying an ammonium salt gradient to the flue gas;
wherein the applying an ammonium salt gradient comprises applying:
a first ammonium salt concentration at a first stage; and
a second ammonium salt concentration at a second stage.

### Claim 2 (depends on 1)

The method of claim 1 wherein the salt includes ammonium sulfite.

### Claim 3 (depends on 1)

The method of claim 1 wherein the salt includes ammonium bisulfite.

### Claim 4 (depends on 1)

The method of claim 1 wherein the salt includes ammonium sulfate.

### Claim 5 (depends on 1)

The method of claim 1 wherein the first concentration is greater than the second concentration.

### Claim 6 (depends on 5)

The method of claim 5 wherein the applying a first ammonium salt concentration at a first stage comprises spraying absorption circulation liquid on the flue gas in a sulfur dioxide absorption process.

### Claim 7 (depends on 6)

The method of claim 6 wherein the applying a second ammonium salt concentration at a second stage comprises spraying absorption circulation liquid on the flue gas in the sulfur dioxide absorption process.

### Claim 8 (depends on 5)

The method of claim 5 wherein the applying a first ammonium salt concentration at a first stage comprises spraying fine particle washing circulation liquid on the flue gas in a fine particle washing process.

### Claim 9 (depends on 8)

The method of claim 8 wherein the applying a second ammonium salt concentration at a second stage comprises spraying fine particle washing circulation liquid on the flue gas in the fine particle washing process.

### Claim 10

A method for controlling aerosol production during absorption of sulfur dioxide from a flue gas, the method comprising:
applying an ammonium salt gradient to the flue gas; and
applying a reaction condition gradient to the flue gas.

### Claim 11 (depends on 10)

The method of claim 10 wherein the applying a reaction condition gradient comprises providing:
a first temperature at a first stage; and
a second temperature at a second stage.

### Claim 12 (depends on 11)

The method of claim 11 wherein the first temperature is greater than the second temperature.

### Claim 13 (depends on 11)

The method of claim 11 wherein the providing a first temperature at a first stage comprises setting a first temperature in a sulfur dioxide absorption process.

### Claim 14 (depends on 11)

The method of claim 11 wherein the providing a second temperature at a second stage comprises setting a second temperature in a fine particle washing process.

### Claim 15 (depends on 10)

The method of claim 10 wherein the applying a reaction condition gradient comprises providing:
a first pH at a first stage; and
a second pH at a second stage.

### Claim 16 (depends on 15)

The method of claim 15 wherein the first pH is greater than the second pH.

### Claim 17 (depends on 15)

The method of claim 15 wherein the providing a first pH at a first stage comprises spraying absorption circulation liquid on the flue gas in a sulfur dioxide absorption process.

### Claim 18 (depends on 15)

The method of claim 15 wherein the providing a second pH at a second stage comprises spraying absorption circulation liquid on the flue gas in the sulfur dioxide absorption process.

### Claim 19 (depends on 15)

The method of claim 15 wherein the providing a first pH at a first stage comprises spraying fine particle washing circulation liquid on the flue gas in a fine particle washing process.

### Claim 20 (depends on 15)

The method of claim 15 wherein the providing a second pH at a second stage comprises spraying fine particle washing circulation liquid on the flue gas in the fine particle washing process.

### Claim 21 (depends on 10)

The method of claim 10 wherein:
the reaction condition is a temperature gradient defined by an absorption temperature and a washing temperature; and
the applying a reaction condition gradient includes:
controlling the absorption temperature and the washing temperature to reduce an energy consumption;
maintaining an absorption efficiency;
maintaining a limit on ammonia escape; and
maintaining a limit on aerosol escape.

### Claim 22 (depends on 21)

The method of claim 21 wherein the absorption temperature is in the range 30° C. to 70° C.

### Claim 23 (depends on 22)

The method of claim 22 wherein the absorption temperature is in the range 35° C. to 60° C.

### Claim 24 (depends on 23)

The method of claim 23 wherein the absorption temperature is in the range 45° C. to 55° C.

### Claim 25 (depends on 21)

The method of claim 21 wherein the washing temperature is in the range 28° C. to 68° C.

### Claim 26 (depends on 25)

The method of claim 25 wherein the washing temperature is in the range 30° C. to 55° C.

### Claim 27 (depends on 26)

The method of claim 26 wherein the washing temperature is in the range 40° C. to 50° C.

### Claim 28

A method for controlling aerosol production during absorption of sulfur dioxide from a flue gas, the method comprising:
applying an ammonium salt gradient to the flue gas;
cooling and purifying the flue gas;
after the cooling and purifying, absorbing sulfur dioxide; and,
after the absorbing, removing the flue gas with a fine particle washing circulation liquid;
wherein:
the applying an ammonium salt gradient is performed after the purifying and cooling; and
the absorbing and the removing both include:
spraying ammonium sulfite; and
spraying ammonium sulfate.

### Claim 29 (depends on 28)

The method of claim 28 wherein:
the absorbing includes spraying absorption circulation liquid on the flue gas; and
the fine particle washing circulation liquid has:
a pH that is lower than a pH of the absorption circulation liquid; and
an ammonium sulfite concentration less than an ammonium sulfite concentration of the absorption circulation liquid.

### Claim 30 (depends on 28)

The method of claim 28 wherein:
the absorbing includes:
spraying an absorption circulation liquid at a lower stage;
spraying an absorption circulation liquid at an upper stage that is downstream, relative to the flue gas, from the lower stage; and
the absorption circulation liquid at one or both of the lower and upper stages:
comprises:
0.15%-4.95% ammonium sulfite; and
5%-38% ammonium sulfate; and
has a pH value in the range 4-6.6;
wherein the ammonium sulfite concentration of the upper stage absorption circulation liquid is lower than the ammonium sulfite concentration of the lower stage of the absorption circulation liquid.