SU1604146A3 - Composition for removing sulfur dioxide from hot gases - Google Patents

Abstract

A process is described for the removal of SO2 from hot flue gases (produced from the combustion of carbon-containing fuels) by means of scrubbing using a solvent having a physical action. After uptake of the SO2, the solvent is regenerated and returned to the scrubbing stage. In order to overcome disadvantages of known solvents, such as hydrolysis and high energy consumption, for example as is the case with dimethylformamide, it is proposed to use a solvent comprising over 50% tetraethylene glycol dimethyl ether for the scrubbing.

Description

This invention relates to compositions for removing 50 from hot gases, such as flue gases, caused by the combustion of natural fuels — coal or fuel oil at power plants, or waste from 1 Kpausa process gases.

The purpose of the invention is to increase the absorption capacity.

The composition contains, in wt%: tetraethylene glycol dimethyl ether 60-80, triethylene glycol dimethyl ether 15-25; pentaethylene glycol dimethyl ether 2.5-7.5 and methyl triethylene glycol 2.5-7.5.

The composition is prepared, for example, by introducing a mixture of tri-, tetra- and pentaethylene glycol monomethyl ethers with water into a stainless steel reactor.

heating the mixture before stirring and introducing at a sufficient rate into the reactor a stoichiometric amount of molten metallic sodium at a temperature C. The temperature of the reaction mixture is maintained in the range 105-115 ° C, if necessary by cooling. The formation of 1YS during the reaction of hydrogen is released. After the addition of metallic sodium is completed, methyl chloride is introduced into the reactor in an amount equal to 115% of the stoichiometric amount. The resulting sodium chloride is removed by centrifugation and a desalted solvent mixture is obtained.

The composition may contain up to 10% water, preferably 2-8%. It is advisable for flue gases that are

O5

about

four

about:

 cm

 sixteen

also contain dust or halogen hydrogen. Water reduces the loss of vapor wash composition due to the fact that it is again washed out with water with the help of water in the head of the absorption column.

The composition was tested at a temperature of 25 ° C and a pressure of 760 mm Hg. It was in contact with the gas phase with a concentration of 30 in which during the entire measurement period it was 500-1000 ppm. After 70, 570 and 1100 hours of operation, the composition was analyzed. Results by definition

- - ± ± 1 k. J i 1 Lf С D С

To determine the specific solubility of SO, at 25 C and 760 mm Hg, the following:

SO solubility. 3 /

nm / m mm Hg 20

0.93

0.94

1.0

1,325

The composition is resistant to the gas to be purified, therefore, it does not need to be replaced even after 1100 hours of operation.

The pressure of the vapor of the vapor over the solution corresponding to the composition described is 1 mm Hg. at 20 C and 5 mm Hg at 50 s.

The table shows comparative with the prototype data on the absorption capacity, measured at 30 ° C and a partial pressure of SO. Equal to 2.5 mbar.

The composition was used in the purification of gases.

Example 1. The cleaning was subjected to 1.6-10 nm / h of flue gas of a thermal power plant with a power of 500 MW, operating on coal, the sulfur content in which was 3.5%. The flue gas had the following 1} 1st composition, about,%: N

76.6, - 0 2.1; C02 12.2; so + so /

0.24 (3840 nm% 11 t / h), 8.86. The flue gas was washed with the absorbent of the proposed composition in the amount of 1600 t / h. The residual content of SOj in the purified gas was equal to 100 h, per mn (le leOHMVM 480 kg / h). The degree of purification from SO was 95.6%. The steam consumption for regenerating the high absorbent is about 30 t / h at a pressure of 2 Char.

604

- five

ten

15

20

25

35

40

five

1464

Example 2. The Claus process was treated in an amount of 2000 kmol / h. The composition of the gas mol.%: H 0,62; K 58.52, CO 0.04-CO 1.06; No, 0.10; 0.87-, 80 O, -33; residual sulfur 0.16 H O 38.30.

The gases leaving the sulfur condenser were installed in a Claus furnace, heated in a furnace to 280 ° C. All combustible components in the catalytic reactor turned into 00, and SO, After peaKTdpoM, the gas had a temperature of about. He rrSj ln., S,

Then the hot gas was cooled to 90 ° C. This gas was irrigated in the wash column with an absorbent to remove SO ,. The cleaned gas (1.637.8 mol / h) left the column through the head, was heated to 250 ° C and was led off to the chimney. This gas had a cobalt composition, mol% CO2, 2.28 /, 82 ,. B, V5, SO ,, less than 10 parts per million. A saturated absorbent was removed from the washing column and regenerated by heating. The fraction with which it was isolated (41 kmol / h) had the following composition, mol%: N2 1.42; COg 1 ,,. 2. 96.87, - all pair. The fraction was again diverted to the Klaus plant.

As follows from the examples, the proposed composition is applicable in DP of cleaning waste gases from SO. Its absorptive capacity according to the table is 370-450 bar, which exceeds the absorptive capacity of the known absorber, equal to 80 Nm7 t. Bar. /

Claims (1)

Invention Formula A composition for removing sulfur dioxide from hot gases based on organic esters, characterized - in that, for the purpose povsh1eni absorbency as it contains esters tetraztilengli- to ldimetilovy ether tryetilenglikol- Dimetilovyi ether, dimethyl ether and pentaetilenglikol- metiltrietilengli- stake with the following content of ingredients, wt.%: