PL152793B1 - Method for purifying industrial waste gases by removing acidic gaseous pollutants - Google Patents

Description

REPUBLIC POLAND PATENT DESCRIPTION 152793 Additional patent to patent no - 1 Reported: 87 04 06 (P. 265028) Int. Cl. ⁵ B01D 53/14 B01D 53/34 Priority SZYTELBIA OFFICE j 5 LH £ PATENT Application announced: 88 10 27 RP Patent description published: 1991 06 28

Inventor: Jerzy Warych

Authorized by the patent: Warsaw University of Technology, Warsaw (Poland)

METHOD OF CLEANING INDUSTRIAL OFF GASES FROM ACID GAS POLLUTANTS

The present invention relates to a method of purifying industrial waste gases from acid gas pollutants. ,

The methods of removing acidic pollutants from industrial waste gases, known from the American patents No. 4,246,242 and 4,273,750 and from the Polish patent description No. 128 130, consist in the absorption of these pollutants in a stream of an alkaline liquid sprayed into droplets combined with simultaneous drying of these drops. This leads to dry purification products in the form of a powder, which is a mixture of reaction products of gaseous pollutants with alkali droplets, a solid residue of unreacted alkali and possible other solid gas pollutants separated together with said products. However, gas cleaning products separated in the form of a dusty powder pose many operational difficulties and are a source of secondary pollution of the natural environment. '. The aim of the invention was to develop a method of purifying industrial flue gases from acid gaseous pollutants ensuring obtaining dry, non-dusting granules and enabling the purification process to be carried out in one process line.

The method according to the invention consists in introducing the stream of polluted gases into the upper part of the process apparatus constituting the spray apparatus co-current with the stream of alkaline absorbent, which is sprayed into droplets smaller than 200 µm.

^Gle spread ^dust Łu alosortenta alkaline ^{g s} head carries at least ¹⁰⁰ ° and of applying them ^g Molar ^yards by the gas contained in the acidic impurities is 1.0-1.6. Subsequently, the acidic pollutants separated from the gas in the form of dust with a moisture content of up to 5% by mass are granulated in the lower part of the process apparatus constituting the fluid bed granulator by feeding an inert gas in countercurrent to the polluted gas stream and an alkaline absorbent. The granulation liquid is optionally fed to the resulting fluidized bed

152 793

152 793 in an amount that maintains the temperature of the treated gases above the dew point temperature. Advantageous results are obtained by using an alkaline sorbent solution as granulating liquid.

The method according to the invention is technologically simple and enables the removal of acidic pollutants from waste gases from industrial processes in one apparatus »! simultaneous granulation of gas cleaning products. The method according to the invention is used to remove acid pollutants from emission sources such as power and heating boilers, metallurgical and industrial furnaces, sintering machines, cement, lime and glass furnaces or aluminum electrolysers.

The course of the process of removing acid gaseous pollutants from industrial waste gases by the method according to the invention is illustrated in the drawing, which shows the diagram of the device.

Contaminated gases 1 through the gas separation chamber 2 are directed to the upper part of the process apparatus 3, which is the spray apparatus. By means of the spraying device 4, a stream of absorption liquid 5 is sprayed onto fine droplets, which may be a suspension of calcium carbonate, hydrated lime or a soda solution depending on the required reactivity. Acid pollutants are absorbed in the absorption liquid stream and the gases to be treated along with the reaction products flow to the lower part of the apparatus, where the cleaning solids are released in the fluidized bed granulator 6 and are granulated during drying in a fluidized bed, to which a stream of inert gas is fed from below, or part of the stream of treated gas in the amount necessary for fluidization The granulation liquid may be supplied to the fluidized bed in the form of a part of the absorption liquid stream 5. The obtained granulate of gas purification products, unreacted sorbent and possibly part of the dust contained in the gas is discharged from the fluidized bed in a stream 8 through a closed hopper or a transfer pipe. On the other hand, the treated gases, together with the dust carried off, flow through the exhaust conduit 7 to the final dust collector 9, from where they are directed to the chimney 11, and the dust separated in the dust collector may constitute a separate product 10 or may be returned to the fluidized bed.

The method according to the invention is explained in more detail in an exemplary embodiment which, however, does not limit its scope of application.

example. A stream was introduced into the process apparatus tangentially to its inlet chamber^ande^ñ gas at tenure¹⁶⁰° C incl^anderupting^{y 2600 pp}m^S.^ and^{20g / N}m ^^dustu volatile.^WITHand^pabout a stream of the aqueous suspension of the Ca / OH / 2 commercial was sprayed at the outlet of the inlet chamber by the power of a pneumatic nozzle, in which the air pressure was 0.4 MPa. The spray angle was 110 degrees. The calcium hydroxide was introduced in an amount to ensure the molar ratio of Ca / OH / 2 / SO2 = IT2.

From the bottom of the process apparatus, an air stream was supplied to fluidize the bed of the CaSO powder produced in the upper part of the apparatus. with a moisture content of 5% by mass. During the gas residence time in the slurry spray zone, the degree of desulphurization of 65% was obtained, and in the lower part of the apparatus, 35% of the mass of solids introduced into the apparatus with the gas and the slurry separated in the form of granules with a size of <0.5 mm. After sprinkling the fluidized bed with the calcium hydroxide suspension, the degree of gas desulfurization increased to 90% and the obtained granules were up to 2.0 mm in size, being a mixture of fly dust, desulfurization products and unreacted Ca / OH / 2.

Claims (2)

Patent claims 1. A method of purifying industrial waste gases from acid gaseous pollutants consisting in supplying the stream of purified gas with an alkaline absorbent stream, and then removing the purified gas and granulated product, characterized by the fact that the stream of contaminated gases is introduced into the upper part of the process apparatus constituting a co-current spray apparatus. with a stream of alkaline absorbent sprayed onto droplets smaller than 200 µm. rozpyłu wherein the angle is at least ¹⁰⁰ ° C as ^t Osuna ^{k l} can absortenta head aRalkznego ^D contained ^you CH azie ^{g k} wa ^s ch ^Sn Impurity szczeń ^y is 1.0-1.6, and then separated from the acid gas pollutants in the form of · dust with a moisture content of up to 5% by mass are granulated in the lower part of the Fluidizing granulator by supplying an inert gas countercurrently to the stream of polluted gases and an alkaline absorbent and optionally supplying the resulting fluidized bed with a granulating liquid, the granulating liquid being introduced in an amount that maintains the temperature of the gases to be cleaned above the dew point temperature. 2. The method according to p. The method of claim 1, characterized by that an alkaline absorbent solution is used as the granulation liquid.