What are the purification techniques of sulfur dioxide

1, fuel desulfurization

Direct desulfurization is the choice of better anti-poisoning performance of the catalyst, the heavy oil is directly introduced into the catalyst-equipped reactor tower hydrodesulfurization. This method is effective, can make desulfurization of heavy oil sulfur content down to 1%;

Indirect desulfurization, is the first heavy oil distillation at reduced pressure, divided into distillate and residual oil. The distillate oil alone is subjected to high-pressure hydrodesulfurization, and then mixed with the residual oil; or liquefied propane (or butane) as a solvent, the residual oil is processed, and the asphalt is separated out, and then mixed with the distillate oil for hydrotreating.

2, combustion desulfurization:

The concentration of SO2 in the flue gas is generally less than 0.5%, to the desulfurization technology has brought a lot of difficulties, a reasonable choice of flue gas desulfurization process must take into account a variety of factors such as the environment, the economy, society. Flue gas desulfurization methods can be generally divided into two categories: wet and dry.

Spray drying absorption method of flue gas desulfurization: when SO2 is atomized Ca (OH) 2 slurry or Na2CO3 solution absorption, at the same time, the higher temperature of the flue gas to make the droplets dry dehydration, the formation of dry solid waste.

The dry waste (consisting of sulphite, sulphate, unreacted absorbent and fly ash) is captured by a baghouse or an electrostatic precipitator, which is currently the only industrially available dry flue gas desulphurization (FGD) technology and is gradually replacing the traditional wet scrubber.

3, fluidized bed combustion desulfurization:

Fluidized bed combustion is essentially a low-temperature combustion process, there is a localized reducing atmosphere within the furnace, thus reducing the amount of NOx, commonly used desulfurization agent is limestone or dolomite.

They will be crushed into the same particle size with the coal, that is, the particle size of 2mm or so, and coal at the same time to join the furnace, in the 1073-1173K combustion, limestone thermal decomposition precipitation of CO2, the formation of porous calcium oxide and then with the role of SO2, generating sulfates, in order to achieve the purpose of sulfur fixation. Currently fluidized bed combustion desulfurization technology is only applicable to small and medium capacity industrial boilers and kilns.

4, low concentration of SO2 adsorption purification

Activated carbon is generally used as an adsorbent. When the flue gas contains a sufficient amount of water vapor and oxygen, SO2 accompanied by chemical adsorption, chemical reaction on the surface of the activated carbon, SO2 oxidation into SO3, and react with H2O to generate dilute sulfuric acid. Impregnation of the adsorbent with metal salts can increase the rate of adsorption of SO2. The desulfurization rate of this method can reach 90%.

Expanded Information:

Sulfur dioxide is extremely chemical. p>Sulfur dioxide chemical properties are extremely complex, different temperatures can be used as a non-protonic solvent, Louie's acid, reducing agent, oxidizing agent, redox reagent and other various roles.

Liquid sulfur dioxide can also be used as a free radical acceptor. Such as in the presence of azobisisobutyronitrile free radical initiator reacts with vinyl compounds to obtain polysulfone. Liquid sulfur dioxide in the light,

Can be chlorosulfonated with chlorine and alkanes, in the presence of oxygen to produce sulfonic acid. Liquid sulfur dioxide exhibits reduction at low temperatures but oxidation above 300°C

References:

Baidu Encyclopedia - Sulfur Dioxide