永丰棋牌

Ammonia process of desulfurization

A brief description of the technology

Ammonia-fertilizer desulfurization technology uses liquid ammonia (gas ammonia), (waste) ammonium hydroxide, ammonium bicarbonate, urea and other alkaline substances that can produce ammonia as desulfurization absorbent to reacts with the scrubbed flue gas to produce ammonium sulfite, and the generated ammonium sulfite solution is forcibly oxidized by the blown air to produce ammonium sulfate solution, thus completing the desulfurization reaction. The ammonium sulfate solution is concentrated and crystallized by the heat of the original flue gas to generate ammonium sulfate slurry (evaporation crystallization process can also be adopted). The ammonium sulfate slurry is conveyed to the ammonium sulfate post-treatment system through a crystallization pump and is subjected to hydrocyclone and centrifugal separation, drying and packaging to form bagged finished products.

 

Technical features

1. It does not have secondary pollution, waste water, waste residue, and carbon dioxide emission.

2. Wide sources of raw materials: liquid ammonia, ammonium hydroxide, waste ammonium hydroxide, and fertilizer grade ammonium bicarbonate can be used.

3. The byproduct of the desulfurization process is ammonium sulfate fertilizer, which has high utilization value.

4. The desulfurization system has a low liquid-gas ratio and a low energy consumption.

5. Simple processing system, compact flow, less resistance of the plant, and reliable system.

6. The desulfurization column has fast absorption reaction speed, high desulfurization efficiency and strong adaptability to sulfur content in the coal.

 

Applicable scope

Newly built desulfurization plant or desulfurization retrofitting

 

Applicable industries

Chemical industry, thermal power plant, metallurgy, sintering machine, sulfur recovery tail gas, etc.

 

The main chemical reactions of the process are as follows:

The first step is the absorption process based on the reaction of SO2 and NH3 in aqueous solution:

SO2+H2O+×NH3=(NH4)xH2-×SO3

SO2+H2O+×NH3=(NH4)xH2-×SO3

Ammonia is used to remove SO2 from flue gas to obtain intermediate product - ammonium sulfite.

The second step is direct and forcible oxidation of ammonium sulfite by air:

(NH)×H2-×SO3+1/2O2+(2-×)NH3=(NH4)2SO4

(NH)×H2-×SO3+1/2O2+(2-×)NH3=(NH4)2SO4

 

Process flow

The flue gas outside the battery limit enters the multi-functional desulfurization column through the inlet duct, and enters the dust removal device after scrubbing, cooling, SO2 absorption and demisting to complete the control and scrubbing of particles in the flue gas, ensuring that the flue gas index at the outlet of the desulfurization column reaches the ultra-low emission requirement. The desulfurized net flue gas is returned to the original stack or discharged through the direct-discharge stack on the top of the column.

Sulfur dioxide in the flue gas is absorbed, and the formed ammonium sulfite solution is subjected to forced oxidation, concentration and crystallization to obtain ammonium sulfate slurry with a certain solid content. The slurry is conveyed to the ammonium sulfate post-treatment system through a crystallization pump, and the solid ammonium sulfate product is produced through the processes of hydrocyclone and centrifugal separation, drying, packaging and the like.