The reactor for catalytic gas purification
(57) Abstract:The invention relates to chemical apparatus and can be used for cleaning of gases from nitrogen oxides, neutralization of exhaust gases from organic impurities. Contains the bottom and cover with inlet and outlet fittings. The internal volume of the reactor divided by horizontal blank wall into two chambers, each of which iron gratings posted by layers of inert nozzles with catalyst on them that have established heaters. The partition is located between the upper and lower chambers connected by a vertical pipe-mixer located at the axis of the upper chamber. At the top of each camera installed horizontal mixers, in which there are electric heaters. Process for selective reduction of nitrogen oxides in the Central part of the pipe-mixer installed collector-spray of reductant supplied in the form of liquid or vapor phase. This device allows to reduce the intensity and cost of the reactor, to simplify it, while also improving reliability. 3 C.p. f-crystals, 2 Il. The invention relates to chemical devices which, Brazauskas during the manufacture of nitric acid, the separation of sulfuric and nitric acids, etc. in Addition, the reactor can be used for catalytic neutralization of gas emissions from organic impurities.Known contact apparatus for neutralization of exhaust gases from organic substances and nitrogen oxides in the so-called non-stationary mode [RF Patent 1829173, B 01 D 53/34, 1997; RF patent 2058186, 10.09.99, ed. mon. The USSR 1011950, B 01 D 53/34, 15.04.1983, ed. St. USSR 1535619, 15.01.90, pat. PL 154894, B 01 D 53/36, 28.02.1992; RF patent 2064331, B 01 J 8/04, 16.03.1994].A characteristic feature of such devices is the need for heat in the chemical reaction zone for carrying out the process in autothermal mode. Typically, the exhaust gases have a low concentration of components to be cleared, their adiabatic heating is relatively low, and the process of neutralization in a stationary mode could not be implemented. Introduced into the reaction zone additional heat increases the adiabatic warming up to the value required to maintain the process of neutralization in autothermal mode.The closest is the contact device described in [Pat. PL 154894, B 01 D 53/36, 28.02.1992]. The apparatus (Fig.1) consists of verticalheader. The casing is divided by a vertical partition into two chambers, in which a grid-iron lattice posted two of the same volume of the layer of inert packing, which poured on top of the same volume of the catalyst layers. At the bottom under the grate bars are fittings supply - gas outlet.When the contact apparatus, the catalyst is heated to the temperature of the beginning of a chemical reaction, the cleaned gas is fed first to one chamber and exits from the apparatus through another camera. After a certain time, called politicla, the gas supply cameras change on the other, thereby making the non-stationary mode of neutralization. The heat of the chemical reaction is always in the catalyst layers. At low concentrations of the gases to be cleared when the heat of the chemical reaction for its holding in autothermal mode is not enough, additional heat introduced by the inclusion of heaters.The construction of the contact apparatus of the prototype does not allow to do the cleaning gas in a more economical mode because of the relatively large heat loss to the environment - especially in the area of high temperatures (~400o
the casing is divided into two chambers by a horizontal partition;
cameras are placed in the housing one above the other;
the chambers are connected with each other by a vertical pipe-mixer, placed along the axis of the upper chambers;
removable heaters placed in a horizontal mixers with holes for the passage of gas through them;
process for selective reduction of nitrogen oxides in the Central part of the pipe-mixer installed collector-spray, which sum up the reducing agent in the form of liquid or vapor phase.Example 1.In Fig.1 shows the construction of the rector, designed for selective catalytic purification of gases from nitrogen oxides.Gas efficiency of 5-10 thousand m33
The temperature of the nitrous gases 20-30oWITH,
The temperature of the gas in the system:
- the maximum in the reaction zone, 450oWITH,
- working in the catalyst bed, 320-350oWITH,
- input-output gas in the device variable for politicla 20-200oWITH,
- start chemical reactions 180-200oC.The calculated hydraulic resistance of 400 mm of water. Art.Total design capacity of the electric heater 56 kW.For carrying out the process under specified conditions - gas volume, concentration, amount of catalyst and inert nozzles, hydraulic resistance and other requirements, the diameter of the reactor amounted to 2.8 m with a total height of 7.4 mEstimated heat loss from the apparatus into the environment up to 10500 kcal/h (at ambient air temperature - 40oC), which is ~21% of the installed capacity of electric heaters.Example 2 (prototype). Same as in example 1.The calculated heat loss to the environment 32% more than in the apparatus in example 1, and constitute ~13860 kcal/hThus, the proposed design of the reactor more komro have the same thermal stresses. 1. The reactor for catalytic gas purification from nitrogen oxides, neutralization of exhaust gases from organic and other impurities bottom and cover with inlet and outlet fittings, divided by a partition into two chambers, each of which iron gratings posted by layers of inert nozzles with catalyst on them that have established heaters, characterized in that the partition separating the internal volume of the reactor, made of horizontal deaf and is located between the upper and lower chambers connected by a vertical pipe-mixer located at the axis of the upper chamber.2. The reactor under item 1, characterized in that the upper part of each camera installed horizontal mixers.3. The reactor under item 1 or 2, characterized in that the heaters are arranged in a horizontal mixers.4. The reactor according to any one of paragraphs. 1-3, characterized in that the process for selective reduction of nitrogen oxides in the Central part of the pipe-mixer additionally installed collector-spray of reductant supplied in the form of liquid or vapor phase.
FIELD: production of aluminum in cells with self-fired anodes, possibly processes for cleaning anode gases.
SUBSTANCE: method comprises steps of accumulating anode gases, preliminarily combusting them together with air in burner devices mounted in cells; supplying gas-air mixture after preliminary combustion of anode gases along gas duct to stage of dust and gas trapping and blowing out to atmosphere. Before supplying gas-air mixture from burner devices to stage of dust and gas trapping, it is fed to process for oxidizing roasting; heated up to temperature 800-1100°C and then it is cooled until 230-290°C and heat is used for production needs.
EFFECT: lowered content of carbon, resin and CO in exhaust gases.