The method of processing exhaust gases by exposure to electron beams and a device for its implementation

 

(57) Abstract:

The invention can be used for cleaning of gases from sulfur oxides and/or oxides of nitrogen. Method of treatment of exhaust gases, comprising adding ammonia to the waste gas containing sulfur oxides (SOx) and/or oxides of nitrogen (NOx), and then the impact on gas electron beams in order to remove the oxides of sulfur and/or nitrogen oxides, characterized in that the first uniformly mixed gaseous ammonia with air, then form a homogeneous gas-liquid mixture from the gas mixture and water and sbryzgivayut mentioned mixture in the reactor. Effective desulfurization can be implemented, even if the temperature of the treated exhaust gas at the reactor outlet is quite high, this can be reduced concentration of ammonium sulfate in the by-product ammonium sulfate. 2 S. and 2 C.p. f-crystals, 4 Il.

The present invention relates to a method of treatment of exhaust gases by exposure to electron beams and involves adding ammonia to the flue bastards containing sulfur oxides (SOx) and/or oxides of nitrogen (NOxand then the impact on gas electron beam in order to remove the hydroxy is when the exhaust gas containing oxides of sulfur and/or nitrogen, is treated first by adding ammonia to a gas and then the impact on gas electron beam in order to remove sulfur oxides and/or oxides of nitrogen, the removal efficiency of sulfur oxides (hereinafter referred to when the case is referred to simply as "the percentage of desulfurization") tends to increase under conditions of lower temperature. This problem is normally solved by lowering the temperature of exhaust gas in the cooling tower with a water spray before it is sent to the reactor, and adding ammonia inlet in said reactor, after which the gas is exposed to the electron beam. Sometimes the water spray not only in the tower, located upstream, i.e. before the reactor, but also at the entrance of the reactor, and in this case, water is supplied separately from the ammonia gas.

Another problem of the known method is that the percentage of desulfurization is highly sensitive to the temperature of the flue gas to be treated, and to ensure effective desulfurization, the temperature of the flue gas at the outlet of the reactor should be lowered to a temperature close to its dew point, but in this case not all spray or pipeline, going further down stream from the reactor.

In some cases, when the exhaust gas containing oxides of sulfur, is first processed by adding ammonia to a gas and then exposed to an electron beam in order to remove the oxides of sulfur, forming sulphate of ammonia as a by-product; in a known process of this treatment, together with ammonium sulfate is formed in an amount which is by no means insignificant, ammonium sulfate, adversely affecting the service life of the installation, and to use the by-product ammonium sulfate as a fertilizer, sulpham you want to delete.

Closest to the invention is a method of processing exhaust gas containing oxides of sulfur and/or nitrogen comprising adding ammonia to the flue gas with the subsequent influence of the electron beam, and a device containing a reactor for processing exhaust gas feeder for feeding ammonia to the flue gases in the reactor and accelerator electron beam irradiating electron beam to the flue gases in the reactor (EP N326686, M. class. B 01 D 53/35, 09.08.89).

Brief description of the invention.

The present invention is carried out in this desulfurization, even if the temperature of the flue gas treatment process is quite high at the exit of the reactor, and which is able to reduce the concentration of sulpham ammonium byproduct.

Other objectives and advantages of the present invention may become apparent from the following description and the attached drawings.

A brief description of the drawings.

Fig.1 is a flow chart of the method of the present invention for processing exhaust gases by exposure to an electron beam, which involves the formation of a homogeneous gas-liquid mixture of water and a mixture of gaseous ammonia and air and then vbrasyvanie homogeneous mixture in the reactor.

Fig.2 is a flow diagram of a known method of processing exhaust gases by exposure to an electron beam, which involves adding only gaseous ammonia in the reactor.

Fig.3 A depicts an example of a nozzle at two fluids which may be used in the present invention.

Fig. 3, B shows an example of the reducer for use with the nozzle of the two fluids.

Fig. 4 is a graph showing the relationship between temperature is 1.

Detailed description of the invention.

The purpose of the invention can be removed first by homogeneous mixing of gaseous ammonia with air, then the formation of homogeneous gas-liquid mixture from the gas mixture and water and vbrasyvanija mentioned homogeneous mixture in the reactor.

The ratio of water to gas mixture of gaseous ammonia and air depends on various factors, such as the design used nozzles on two current environment, the pressure of the added gas and the pressure of the sprayed water;

Typically, an acceptable range is the range from 0.1 to 20 l/m3. If the ratio of water to gas mixture of gaseous ammonia and air is less, there is a risk of failure in achieving effective desulphurization, and there are also interference from reducing the efficiency of suppressing the formation of sulpham ammonium. On the other hand, if the ratio exceeds 20 l/m3then not all vbrasyvaemye water evaporates, which leads to the formation of waste water or dew formation on the surface of the pipe or tubing downstream after the reactor.

Ammonia should be used in an amount which is determined mainly on ammonium nitrate, accordingly, but to determine the exact amount of ammonia used should also take into account other factors such as the required percentage of desulphurization, the required percentage denitration and concentration of the resulting ammonia, as expressed by the following equation:

< / BR>
where Q is the quantity of exhaust gas in m3N/h;

SOxthe concentration of SOxin ppm (parts per million);

NOxthe concentration of NOxin ppm (parts per million);

CNH2the concentration of the resulting ammonia in ppm (parts per million);

- the required percentage of desulfurization;

- the required percentage denitration.

Water should be used in an amount which, ultimately, is required for regulation of the temperature of exhaust gas at the outlet of the rector in the range of dew point temperature to no more than 100oC. processing method embodied in the invention, the exhaust gas to which is added, the ammonia is exposed to the electron beam, in order SOxwas converted to ammonium sulfate and NOxin the ammonium nitrate, with heat to increase the temperature of the treated exhaust gas is generated in the reactions expressed by the following scheme is + 2NH3+ H2O ---> (NH4)2SO4+ 107,5 kcal/mol

NO + NH3+ 1/2H2O + 3/4O2---> NH4NO3+ 68.9 kcal/mol

Dose exposure to electron beams is selected considering the concentrations of SOxand NOxin the exhaust gas and the required degree of their removal.

The amount of heat generated by the electron beam in calories, as well

the mass of flue gas in kg absorbed dose in kGy/4,1855,

where 4,1855 is the mechanical equivalent of heat in kJ/kcal.

When processing a flue gas obtained from the combustion of fuels, such as coal, oil, or obtained from sintering of iron and steel, water is required in all cases, should be used in quantities for which taken into account the above conditions.

The amount of air that should be used depends on various factors, such as the quantity of the sprayed water, the required size of the water droplets and pressure of water and air, but, ultimately, is in the above range, the relationship between water and gas mixture, i.e., 0.1 to 20 l/m3.

When processing a flue gas containing sulfur oxides, first by adding Ammi is I, the reaction with ammonia is carried out in one of two ways: SO2and SO3contained in the exhaust gas react directly with ammonia according to schemes (1) and (2) below, or, alternatively, SO2oxidized to SO3radicals, such as Ooand HEoformed under the influence of the electron beam, thus obtained SO3then reacts with ammonia according to the scheme (2). As you can see from the fact that both reactions (1) and (2) include NH3and H2O in the left side of the equation, any reaction will be to develop quietly and smoothly with increasing concentrations of ammonia and water, but with the lowering of temperature of the treated exhaust gas:

SO2+ 2NH3+ H2O + 1/2O2---> (NH4)2SO4(1)

SO3+ 2NH3+ H2O ---> (NH4)2SO4(2)

Ammonium sulfate, on the other hand, as expected, it turns out, when SO2reacts according to the reaction scheme (3) below, with ammonia and OH radicalowhich is formed under the influence of the electron beam. The right side of equation (3) includes H2O, so you can see what your reaction is slowed down by increasing the concentration in theO (3)

In the present invention water vpisyvaetsa after mixing it with ready-made gas a gaseous mixture of ammonia and air, so the temperature at the surfaces obtained the smallest drops of an aqueous solution of ammonia is much lower than the temperature of the surrounding gas due to evaporation of water, and the humidity is close to the saturated state. Moreover, aqueous ammonia evaporates simultaneously with water on the surfaces of drops of ammonia, accelerating the reaction scheme (1) or (2) to occur with great speed. On the other hand, the reaction scheme (3) will be slower due to the high concentration of water.

As a result of effective desulfurization can be achieved, even if the processing of the exhaust gas has a relatively high temperature and, moreover, can be suppressed formation of sulpham ammonium.

When spraying a mixture of water with a gas mixture of ammonia and air can sbryzgivat prepared liquid mixture of ammonia, air and water, but in this case it is difficult to change the quantity of the injected water and ammonia independently from each other in accordance with the temperature to be processed exhaust gas and to the fact for storing ammonia in water solution requires large-scale equipment.

Such problems do not occur if ammonia is first mixed with air so that the resulting gas mixture is then mixed with water in the compartment (12) for mixing gas with liquid nozzles on the two fluids before the final wpisywaniem in the reactor.

When mixing ammonia gas with air, carbon dioxide and water in the air react with ammonia to form ammonium bicarbonate or ammonium carbonate, which can potentially clog the pipeline, which passes the mixture of ammonia and air. These connections will either harden or absorb moisture from the transformation into a high-viscosity liquid that will accumulate in the pipeline and, ultimately, becomes a cause of clogging. As a result of various tests conducted by the authors of the present invention using conventional air, found that the problem of clogging of the pipeline can be eliminated by heating the pipeline through which passes a mixture of ammonia and air at a temperature of 60oC and above during the period of time from the mixing of ammonia with air before mixing the obtained gas mixture with water with the formation of the gas-liquid mixture. For this purpose, can be used to nd a mixture of air and ammonia gas) in the nozzle at the two fluids are usually established order of 1-10 CSE/cm2preferably 3-5 CSE/cm2. Before mixing gaseous ammonia with air pipe for supplying ammonia preferably be heated by a suitable means, such as steam or electric heater, to ensure that the ammonia, the current through it will not be liquefied at low temperature ambient air, namely to maintain the ammonia in the gaseous state.

Heat pipe for supplying ammonia should be changed, as described below, because at higher pressures the ammonia tends to liquefaction, even if the temperature is high:

Pressure, CSE/cm2- Temperature,oC

1 - of about -35

3 - about -10

5 - about 3

10 - approximately 23

To further illustrate the invention the following examples are in no way limiting the invention.

Example 1.

The experiment on the processing of the exhaust gas by exposure to the electron beam were carried out in accordance with the flow chart of the method of the invention, shown in Fig. 1, which includes first preparing a gas mixture of ammonia gas and air, then mixing it with water with the formation of gazozhidkostnoi 800 ppm (parts per million) of sulfur and 200 ppm of oxides of nitrogen was cooled to 110oC through the air preheater 2 and the gas heater 3, further cooled to 60oC in a cooling tower with a water spray 4 and directed to the reactor 5. Phase separation of gaseous ammonia (20 m3/h) supplied from the feeder ammonia 6, was mixed with air (1000 m3/hour) in the main mixer 7, and the resulting gaseous mixture, which was passed through the inner tube enclosed in a casing, mixed with water in a gas-liquid mixing compartment of the nozzle 8 into two fluids and the resulting gas-liquid mixture sbrasyvali at the entrance to the reactor 5 from the tip of the nozzle 10 through the core 11, while it was affected by the flow of electron beams (12 KGy) from the accelerator electron beams 9. In the experiment, water was supplied in different quantities from 50 to 200 kg/h to change the temperature at the outlet of the reactor 5, which, as installed, is in correlation with the efficiency of desulphurization, as shown by the solid line in Fig.4. The concentration of sulpham ammonium in side-product ammonium sulfate was 0.05%, which is not the only problem when using a by-product as fertilizer.

Comparative example 1.

Gasoils the major ammonia and conducted an experiment on the processing of the exhaust gas by exposure to an electron beam in accordance with the technological scheme known way, it is shown in Fig.2.

Flue gas from the boiler 1, was passed through the air heater and a gas heater to ensure the same conditions of temperature and concentrations as in Example 1. The thus treated exhaust gas cooled in the tower refrigerator with water spray 4. The amount of water to the spray tower 4, changed to regulate the water temperature at the outlet of the reactor 5. Ammonia (20 m3/h) supplied from the feeder ammonia 6, injectively in the form of gas in the reactor 5. The exhaust gas introduced into the reactor 5 was subjected to the flow of electron beams (12 kGy) from the accelerator electron beam 7. The relationship between the temperature at the reactor outlet and the efficiency of desulphurization shown in Fig.4 by the dashed line. The concentration of ammonium sulphate by-product ammonium sulfate was 2.0% and was too high to allow direct use by-product as fertilizer.

Example 2.

The procedure of Example 1 was repeated except that the temperature of the pipe from the mixing of gaseous ammonia with air before mixing the gas mixture with water to education gazoz the temperature for several weeks without any problems of clogging of the pipeline.

Comparative example 2.

The procedure of Example 2 was repeated except that the temperature of the pipe from the mixing of gaseous ammonia from the air before mixing the gas mixture with water for the formation of a gas-liquid mixture maintained at a temperature of 40oC or normal temperature (about 20oC). The pipe was clogged after a few days of work.

According to the invention effective desulfurization can be carried out even if the temperature of the treated exhaust gas at the reactor outlet was quite high, and it is possible to reduce the concentration of sulpham ammonium byproduct ammonium sulfate.

1. The method of processing exhaust gas, comprising adding ammonia to the waste gas containing sulfur oxides (SOx) and/or oxides of nitrogen (NOx), and then the impact on gas electron beam in order to remove the oxides of sulfur and/or nitrogen from it, characterized in that the first uniformly mixed gaseous ammonia with air, then form a homogeneous gas-liquid mixture from the gas mixture and water and sbryzgivayut homogeneous mixture in the reactor.

2. The method according to p. 1, characterized in that otoso ammonia in the gas mixture is at a level needed to convert sulfur oxides and/or oxides of nitrogen in the gas mixture in the ammonium sulfate and/or ammonium nitrate, respectively, and the amount of water is necessary to regulate the temperature of exhaust gas at the outlet of the reactor in the temperature range from the growth point of water to not more than 100oC.

3. The method according to p. 1 or 2, characterized in that the temperature of the pipeline through which passes a mixture of ammonia and air support at 60oC or higher during the period of time from the mixing of gaseous ammonia with air before mixing the resulting mixture with water for the formation of a gas-liquid mixture.

4. A device for processing waste gas containing sulfur oxides (SOx) and/or oxides of nitrogen (NOx) includes a reactor for processing exhaust gas feeder for feeding ammonia to the flue gases in the reactor and accelerator electron beam irradiating electron beam to the flue gases in the reactor, wherein the reactor comprises a nozzle into two fluid environment containing the tip and the Department for mixing gas with liquid, and gas mixer, which is first uniformly mixed gaseous ammonia with air education is MES mentioned gas mixture and water and inject the specified gas-liquid mixture in the exhaust gas in the reactor from the nozzle tip.

 

Same patents:

Pulsation reactor // 2150994

The invention relates to a method of slowing biochemical, chemical and other processes due to the electromagnetic interaction

The invention relates to a plasma chemical engineering and is intended for chemical thermal decomposition of liquid reagents

The invention relates to methods for petroleum products and can be used in refining and petrochemical industries

The invention relates to the production of intermediate products for the synthesis of peptides, symmetrically substituted derivatives diaminocarbenes acid of the formula I

< / BR>
in which a and b independently of each other means a radical-OR where R represents one or multiply halogenated linear, branched or cyclic alkyl radical WITH1-C5or the radical - CH2- X, where X represents the radicals phenyl-, -och3, -CCI3, -CH2-Y, where Y is a halogen, p-tosilos, if necessary, one or multiply substituted with halogen, NO2or alkoxygroup, a radical of phenyl, 2-pyridyl or radical SiR1R2R3where the residues R1, R2, R3each independently from each other mean a linear or branched alkyl radical WITH1-C4Ali phenyl; E, F each means the residue formula

< / BR>
where W - S-N - benzyl residue, n is an integer from 2 to 10, and the centers of chirality in the compound of the formula I vary according to which source connections

The invention relates to the field of technology and engineering of materials processing reasoning radiation
The invention relates to the field of adsorption technology

The invention relates to a method for cleaning exhaust gases from harmful gaseous emissions and can be used for purification of exhaust gases of power plants and other industrial enterprises
The invention relates to the field of power engineering, in particular to the burning of coal, oil, and other fuels in the furnaces of the boilers of thermal power plants, heating plants, etc

The invention relates to methods for removal of acid pollutants such as SO2and NOxfrom flue gases by radiation exposure, particularly from industrial flue gases emitted heating plants and power plants, as well as to a device for the removal of SO2and NOxfrom industrial flue gases

The invention relates to a method of purification of smoke, soot or exhaust gases from sulfur and nitrogen oxides (SO2and NOx), and is intended mainly for purification of exhaust gases from engines operating mode ground tests

The invention relates to a method of cleaning gases and can be used in energy from fuel combustion, coke, coal and chemical industry
Up!