Oy Tampella Ab

Oy Iampella Ab

Timo Kenakkala

Kari Kokkonen

Sirpa L Hamala

Seppo Tuominiemi

Tuomo Ruohola

Pentti Janka

Heikki Ahonen

Jouko Laine

Hannu Alppi

Pertti Kokkonen

Matti Heikkila

Martti Lehtimaki

The invention relates to a process for the removal of sulfur dioxide from hot flue gases (8) which have been obtained by burning a sulfur-containing substance (4) in a boiler (1). In the process, a substance (6), such as lime or limestone, which reacts with sulfur dioxide to form a solid product is fed into the boiler or into the reaction zone (2) subsequent to the boiler, the hot flue gases (8) are cooled in the reaction zone (2) by feeding into it at maximum such an amount of water as the hot flue gases are capable of evaporating, and the substantially dry solid products are separated (3) in the form of dust (10) from the cooled flue gases. According to the invention, the flue gases (11) thus obtained are scrubbed (13) with an alkaline aqueous solution (15) in order to remove the remaining sulfor dioxide and dust from the flue gases, and part (9') of the cycled scrubbing solution (9) is fed into the boiler (1) or the reaction zone (2) in order to evaporate the water from this solution.

Process for the removal of sulfur dioxide from hot flue gases

A method of producing cement or concrete, comprising the step of adding fly ash to the cement or concrete at the production stage, the fly ash containing lime and reaction products from the reaction occurring between lime and sulphur oxides in connection with the desulphuration of flue gases. To avoid the disadvantageous effects of calcium sulphite and entringite reactions and to increase the used amount of fly ash containing desulphuration waste, the calcium sulphite is oxidized by hydrogen peroxide either before the production of cement or concrete or during the production.

Method of producing cement or concrete

A process for causing gaseous trace element particles to pass from a flowing hot gas into a fine particulate material by means of water. A mixture of the hot gas and water drops is caused to flow substantially upwards at such a velocity that the water drops remain in the gas flow and for a period long enough for most of the mass of the water drops to evaporate in order to cool the gas and to increase its relative humidity. After the gases have reached their wet temperature, they are brought into a turbulent state in order to cause the dust particles and the water drops which have decreased through evaporation to impinge against each other in order to produce in the aqueous film which covers the dust particles an exothermal ion reaction between the gaseous water-soluble trace element particles and the fine particles. Thereafter, the mixture is caused to flow further in order to evaporate the remaining water by means of the heat of reaction so that a dry end product is obtained.

Process for removing a constituent from a hot gas stream by exothermic

The invention relates to a process and apparatus for causing the sulfur dioxide of flue gases to react to form solid sulfates and sulfites which can be separated from the flue gases. Sulfur dioxide containing flue gases (16) are directed according to the invention into one end of an oblong reaction zone (4), in addition to which pulverous calcium compounds and water are directed separately into the reaction zone at several points, and finally from the opposite end a flue gas suspension is withdrawn and directed to dust separation (5). By feeding the pulverous reagent and the water separately into the reactor 4, the problems involved in the preparing, handling and spraying of an aqueous slurry are avoided, in addition to which the retention time and the reaction conditions can be regulated easily in the oblong reactor 4.

Process for causing the gaseous sulfur compounds of flue gases to react

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Tampere, Finland

Timo Kenakkala