CN102359959A - Method for determining sulfur dioxide oxidation rate of selective catalytic reduction denitration catalyst - Google Patents

Abstract

The invention relates to a method for determining a sulfur dioxide oxidation rate of a selective catalytic reduction denitration catalyst. The method is characterized by comprising the following steps of 1, controlling a temperature of a gas trap in a range of 85 to 95 DEG C, and connecting the gas trap to a boiler for flue gas trapping, wherein a gas absorption bottle is connected to the gas trap and a H2O2 solution for absorption of SO2 gas is placed in the gas absorption bottle, 2, starting a suction pump and sucking out flue gas in the boiler, 3, after sampling, flushing the flue gas trapped by the gas trap by a sulfuric acid solution having a pH value of 5 to 6, and collecting the solution obtained by flushing, wherein the H2O2 solution absorbs SO2 gas to form absorption liquid, 4, through a sodium borate solution, titrating the solution obtained by flushing until a pH value of the solution obtained by flushing reaches 5.5, and calculating the concentration SO3(ppm) of SO3, 5, analyzing the concentration of SO2 in the absorption liquid by a precipitation titration method, and 6, calculating an oxidation rate of SO2. The method can guarantee that water vapor in flue gas does not condense; SO2 does not react with oxygen and water vapor; and a measuring result is accurate.

Description

Measure the method for denitrifying catalyst with selective catalytic reduction oxidizing sulfur dioxide rate

Technical field

The present invention relates to a kind of method of measuring the oxidizing sulfur dioxide rate, especially a kind of method of measuring denitrifying catalyst with selective catalytic reduction oxidizing sulfur dioxide rate.

Background technology

Along with country during " 12 " is more and more stricter to the control of discharged nitrous oxides; Simple low nitrogen burning technology can't satisfy the requirement of existing emission standard, and the coal-burning power plant uses SCR (SCR) technology because of its high-efficiency reliable denitration performance has begun at home.The cardinal principle of SCR is with NH ₃Be reductive agent, under the effect of catalyzer, optionally with NO _xBe reduced into N ₂At present most widely used is honeycomb fashion vanadium tungsten titanium catalyst.

Owing to also have SO in the boiler smoke ₂Deng gas, and the active component vanadium in the catalyzer also can be with the SO in the flue gas in the process of catalytic degradation NOx ₂Oxidation generates SO ₃, SO ₃Generate ammonium hydrogen sulfate with unreacted reductive agent ammonia react in the SCR denitrification process.Ammonium hydrogen sulfate has viscosity, can work the mischief to air preheater and beds.Ammonium hydrogen sulfate has hydroscopicity at low temperatures, after suction from flue gas, can cause corrosion on Equipment to stop up.Behind flue gas process SCR reactor and the air preheater hot arc; Exhaust gas temperature reduces; The gaseous sulfuric acid hydrogen ammonium that when temperature is reduced to below 185 ℃, has generated in the flue gas can solidify on the heat transfer element of cold section of air preheater down, causes cold section salification of air preheater and fouling, and then influences the normal operation of air preheater.If stick to catalyst surface, can cause catalyst member to stop up, increase catalyst pressure drop or cause catalyst failure.

Therefore, SO in monitoring and the analysis flue gas ₃And H ₂SO ₄Concentration, become regulation and control boiler operatiopn condition, check and accept and estimate the indispensable means of SCR catalyzer.SO ₂Oxygenation efficiency becomes an important indicator estimating SCR catalyst performance and SCR system acceptance.

Summary of the invention

The objective of the invention is to overcome the deficiency that exists in the prior art; A kind of method of measuring denitrifying catalyst with selective catalytic reduction oxidizing sulfur dioxide rate is provided; Realized testing, the data support of control decision is provided for the content of sulfuric anhydride and ammonium sulfate in the performance of estimating denitrating catalyst, the control flue gas and the normal operation that ensures the coal-burning power plant denitrating catalyst oxidizing sulfur dioxide rate.

According to technical scheme provided by the invention, the method for said mensuration denitrifying catalyst with selective catalytic reduction oxidizing sulfur dioxide rate, characteristic is to comprise following processing step:

(1) temperature constant of pilot-gas drip catcher is at 85～95 ℃, and gas trap is connected on the boiler to capture flue gas, on gas trap, is connected with the gas absorption bottle, is contained with in the gas absorption bottle to be used to absorb SO ₂The H of gas ₂O ₂Solution, said H ₂O ₂The mass percentage concentration of solution is 1%～3%;

(2) open aspiration pump, extract the flue gas in the boiler, the control speed of exhaust is 3～5L/min, and the gas sample volume is V, and the pressure of gas meter is Pm, and the temperature of gas meter is t;

(3) after sampling finished, using pH value was the flue gas on 5～6 the sulfuric acid solution flushing gas drip catcher, collection washing fluid, SO ₂Gas is by H ₂O ₂The solution absorption liquid that is absorbed;

(4) using the dobell's solution titration washing fluid of 0.02mol/L is 5.5 up to pH, calculates SO through following formula ₃Concentration SO ₃(ppm):

${\mathrm{SO}}_3\left(\mathrm{ppm}\right)=\frac{0.224\×a\×f}{V\×\frac{273}{273+t}\×\frac{\mathrm{Pa}+\mathrm{Pm}-\mathrm{Pv}}{760}}\×1000\left(\mathrm{ppm}\right),$

Wherein, the volume of the 0.02mol/L dobell's solution that a=consumes, unit is ml;

F=2, promptly concentration is the factor of the sodium borate of 0.02mol/L;

V=gas sample volume, unit are L;

T=gas meter temperature, unit is ℃;

Pa=atmospheric pressure, unit are mmHg;

Pm=gas meter pressure, unit are mmHg;

Water saturation vapour pressure under the Pv=gas meter temperature, unit is mmHg;

(5) adopt precipitation titration to analyze the SO in the absorption liquid ₂Concentration, draw SO ₂Concentration SO ₂(ppm): the absorption liquid of getting 5～25ml is put into conical flask; Add 35～50ml isopropyl alcohol, 0.5～2ml acetate adds 3～5 indicator arsenazo III solution; Present blueness with the barium acetate solution titration absorption liquid of 0.05mol/L again and do not decorporate, calculate SO through following formula again ₂Concentration,

${\mathrm{SO}}_2\left(\mathrm{ppm}\right)=\frac{{\mathrm{afV}}_l/V_s}{V_g\frac{273}{273+t}\frac{\mathrm{Pa}+\mathrm{Pm}-\mathrm{Pv}}{760}}\·1000,$

Wherein, the volume of the 0.05mol/L barium acetate that a=consumes, unit is ml;

F=1.12 is the factor of 0.05mol/L barium acetate;

V ₁The cumulative volume of=absorption liquid, unit are ml;

V _sThe absorption liquid volume that=titration is used, unit is ml;

V _g=gas sample volume, unit are 1;

T=gas meter temperature, unit is ℃;

Pa=atmospheric pressure, unit are mmHg;

Pm=gas meter pressure, unit are mmHg;

Water saturation vapour pressure under the Pv=gas meter temperature, unit is mmHg;

(6) SO ₂The mensuration of oxygenation efficiency: adopt following formula to calculate SO ₂Oxygenation efficiency η SO ₂,

${\mathrm{\η}}_{{\mathrm{SO}}_2}(\%)=\frac{{\mathrm{SO}}_3\left(\mathrm{ppm}\right)}{{\mathrm{SO}}_2\left(\mathrm{ppm}\right)+{\mathrm{SO}}_3\left(\mathrm{ppm}\right)}\×100.$

The present invention has the following advantages:

(1) SO in the flue gas ₃/ H ₂SO ₄All exist, guarantee that nicotinic acid steam all gets in the spiral condensation and collection pipe in downstream with gaseous form;

(2) get into the SO of spiral pipe with gaseous form ₃And H ₂SO ₄Condensation immediately forms the acid mist droplet, and when utilizing the isokinetic sampling, the centrifugal force that in spiral pipe, produces in the flue gas aspiration procedure is with the H of droplet shape ₂SO ₄Be thrown to the wall of spiral pipe, and utilize the strong adsorbability of acid mist droplet, stick on the collection tube wall, be convenient to collect fully;

(3) collection tube places the water-bath more than 85～95 ℃, and this temperature is higher than the dewpoint temperature of water, and the water vapour in the flue gas can condensation, SO ₂Can not react in this temperature, can not produce interference, measure accurately with oxygen, steam.

Embodiment

Below in conjunction with specific embodiment the present invention is described further.

Embodiment one: a kind of method of measuring denitrifying catalyst with selective catalytic reduction oxidizing sulfur dioxide rate comprises following processing step:

(1) temperature constant of pilot-gas drip catcher is at 93 ℃, and gas trap is connected on the boiler to capture flue gas, on gas trap, is connected with the gas absorption bottle, is contained with in the gas absorption bottle to be used to absorb SO ₂The H of gas ₂O ₂Solution, said H ₂O ₂The mass percentage concentration of solution is 2.1%;

(2) open aspiration pump, extract the flue gas in the boiler, the control speed of exhaust is 4L/min, and the gas sample volume is V=120L, and the pressure of gas meter is Pm=43mmHg, and the temperature of gas meter is t=35 ℃;

(3) after sampling finished, using pH value was the flue gas on 5.5 the sulfuric acid solution flushing gas drip catcher, collection washing fluid, SO ₂Gas is by H ₂O ₂The solution absorption liquid that is absorbed;

(4) using the dobell's solution titration washing fluid of 0.02mol/L is 5.5 up to pH, calculates SO through following formula ₃Concentration SO ₃(ppm)=5.0ppm:

${\mathrm{SO}}_3\left(\mathrm{ppm}\right)=\frac{0.224\×a\×f}{V\×\frac{273}{273+t}\×\frac{\mathrm{Pa}+\mathrm{Pm}-\mathrm{Pv}}{760}}\×1000\left(\mathrm{ppm}\right),$

Wherein, a=1.20ml, the volume of the 0.02mol/L dobell's solution of consumption;

F=2, promptly concentration is the factor of the sodium borate of 0.02mol/L;

V＝120L；

t＝35；

Pa＝760mmHg；

Pm＝43mmHg；

Pv＝42.1mmHg；

(5) adopt precipitation titration to analyze the SO in the absorption liquid ₂Concentration, draw SO ₂Concentration SO ₂(ppm): the absorption liquid of getting 20ml is put into conical flask; Add the 40ml isopropyl alcohol, 1ml acetate adds 4 indicator arsenazo III solution; Present blueness with the barium acetate solution titration absorption liquid of 0.05mol/L again and do not decorporate, calculate SO through following formula again ₂Concentration SO ₂(ppm)=489.6ppm,

${\mathrm{SO}}_2\left(\mathrm{ppm}\right)=\frac{{\mathrm{afV}}_l/V_s}{V_g\frac{273}{273+t}\frac{\mathrm{Pa}+\mathrm{Pm}-\mathrm{Pv}}{760}}\·1000,$

Wherein, a=9.31ml;

F=1.12 is the factor of 0.05mol/L barium acetate;

V ₁＝100ml；

V _s＝20ml；

V _g＝1201；

t＝35℃；

Pa＝760mmHg；

Pm＝43mmHg；

Pv＝42.1mmHg；

(6) SO ₂The mensuration of oxygenation efficiency: adopt following formula to calculate SO ₂Oxygenation efficiency η SO ₂=1.01%,

${\mathrm{\η}}_{{\mathrm{SO}}_2}(\%)=\frac{{\mathrm{SO}}_3\left(\mathrm{ppm}\right)}{{\mathrm{SO}}_2\left(\mathrm{ppm}\right)+{\mathrm{SO}}_3\left(\mathrm{ppm}\right)}\×100.$

Embodiment two: a kind of method of measuring denitrifying catalyst with selective catalytic reduction oxidizing sulfur dioxide rate comprises following processing step:

(1) temperature constant of pilot-gas drip catcher is at 95 ℃, and gas trap is connected on the boiler to capture flue gas, on gas trap, is connected with the gas absorption bottle, is contained with in the gas absorption bottle to be used to absorb SO ₂The H of gas ₂O ₂Solution, said H ₂O ₂The mass percentage concentration of solution is 2.5%;

(2) open aspiration pump, extract the flue gas in the boiler, the control speed of exhaust is 4.2L/min, and the gas sample volume is V=126L, and the pressure of gas meter is Pm=46mmHg, and the temperature of gas meter is t=36 ℃;

(3) after sampling finished, using pH value was the flue gas on 5.5 the sulfuric acid solution flushing gas drip catcher, collection washing fluid, SO ₂Gas is by H ₂O ₂The solution absorption liquid that is absorbed;

(4) using the dobell's solution titration washing fluid of 0.02mol/L is 5.5 up to pH, calculates SO through following formula ₃Concentration SO ₃(ppm)=4.0ppm,

${\mathrm{SO}}_3\left(\mathrm{ppm}\right)=\frac{0.224\×a\×f}{V\×\frac{273}{273+t}\×\frac{\mathrm{Pa}+\mathrm{Pm}-\mathrm{Pv}}{760}}\×1000\left(\mathrm{ppm}\right),$

Wherein, a=1.00ml, the volume of the 0.02mol/L dobell's solution of consumption;

F=2, promptly concentration is the factor of the sodium borate of 0.02mol/L;

V＝126L；

t＝36℃；

Pa＝760mmHg；

Pm＝46mmHg；

Pv＝44.6mmHg；

(5) adopt precipitation titration to analyze the SO in the absorption liquid ₂Concentration, draw SO ₂Concentration SO ₂(ppm): the absorption liquid of getting 15ml is put into conical flask; Add the 35ml isopropyl alcohol, 1ml acetate adds 4 indicator arsenazo III solution; Present blueness with the barium acetate solution titration absorption liquid of 0.05mol/L again and do not decorporate, calculate SO through following formula again ₂Concentration SO ₂(ppm)=508.8ppm,

${\mathrm{SO}}_2\left(\mathrm{ppm}\right)=\frac{{\mathrm{afV}}_l/V_s}{V_g\frac{273}{273+t}\frac{\mathrm{Pa}+\mathrm{Pm}-\mathrm{Pv}}{760}}\·1000,$

Wherein, a=7.60ml, the volume of the 0.05mol/L barium acetate of consumption;

F=1.12 is the factor of 0.05mol/L barium acetate;

V ₁＝100ml；

V _s＝15ml；

V＝126L；

t＝36℃；

Pa＝760mmHg；

Pm＝46mmHg；

Pv＝44.6mmHg；

(6) SO ₂The mensuration of oxygenation efficiency: adopt following formula to calculate SO ₂Oxygenation efficiency η SO ₂=0.78%,

${\mathrm{\η}}_{{\mathrm{SO}}_2}(\%)=\frac{{\mathrm{SO}}_3\left(\mathrm{ppm}\right)}{{\mathrm{SO}}_2\left(\mathrm{ppm}\right)+{\mathrm{SO}}_3\left(\mathrm{ppm}\right)}\×100.$

Embodiment three: a kind of method of measuring denitrifying catalyst with selective catalytic reduction oxidizing sulfur dioxide rate comprises following processing step:

(1) temperature constant of pilot-gas drip catcher is at 90 ℃, and gas trap is connected on the boiler to capture flue gas, on gas trap, is connected with the gas absorption bottle, is contained with in the gas absorption bottle to be used to absorb SO ₂The H of gas ₂O ₂Solution, said H ₂O ₂The mass percentage concentration of solution is 2.2%;

(2) open aspiration pump, extract the flue gas in the boiler, the control speed of exhaust is 3.9L/min, and the gas sample volume is V=118L, and the pressure of gas meter is Pm=32mmHg, and the temperature of gas meter is t=30 ℃;

(3) after sampling finished, using pH value was the flue gas on 5.5 the sulfuric acid solution flushing gas drip catcher, collection washing fluid, SO ₂Gas is by H ₂O ₂The solution absorption liquid that is absorbed;

(4) using the dobell's solution titration washing fluid of 0.02mol/L is 5.5 up to pH, calculates SO through following formula ₃Concentration SO ₃(ppm)=3.5ppm,

${\mathrm{SO}}_3\left(\mathrm{ppm}\right)=\frac{0.224\×a\×f}{V\×\frac{273}{273+t}\×\frac{\mathrm{Pa}+\mathrm{Pm}-\mathrm{Pv}}{760}}\×1000\left(\mathrm{ppm}\right),$

Wherein, a=0.83ml, the volume of the 0.02mol/L dobell's solution of consumption;

F=2, promptly concentration is the factor of the sodium borate of 0.02mol/L;

V＝118L；

t＝30℃；

Pa＝760mmHg；

Pm＝32mmHg；

Pv＝31.8mmHg；

(5) adopt precipitation titration to analyze the SO in the absorption liquid ₂Concentration, draw SO ₂Concentration SO ₂(ppm): the absorption liquid of getting 15ml is put into conical flask; Add the 35ml isopropyl alcohol, 1ml acetate adds 4 indicator arsenazo III solution; Present blueness with the barium acetate solution titration absorption liquid of 0.05mol/L again and do not decorporate, calculate SO through following formula again ₂Concentration SO ₂(ppm)=502.7ppm,

${\mathrm{SO}}_2\left(\mathrm{ppm}\right)=\frac{{\mathrm{afV}}_l/V_s}{V_g\frac{273}{273+t}\frac{\mathrm{Pa}+\mathrm{Pm}-\mathrm{Pv}}{760}}\·1000,$

Wherein, a=7.16ml, the volume of the 0.05mol/L barium acetate of consumption;

F=1.12 is the factor of 0.05mol/L barium acetate;

V ₁＝100ml；

V _s＝15ml；

V＝118L；

t＝30℃；

Pa＝760mmHg；

Pm＝32mmHg；

Pv＝31.8mmHg；

(6) SO ₂The mensuration of oxygenation efficiency: adopt following formula to calculate SO ₂Oxygenation efficiency η SO ₂=0.69%,

${\mathrm{\η}}_{{\mathrm{SO}}_2}(\%)=\frac{{\mathrm{SO}}_3\left(\mathrm{ppm}\right)}{{\mathrm{SO}}_2\left(\mathrm{ppm}\right)+{\mathrm{SO}}_3\left(\mathrm{ppm}\right)}\×100.$

Claims (1)

1. a method of measuring denitrifying catalyst with selective catalytic reduction oxidizing sulfur dioxide rate is characterized in that, comprises following processing step:

(1) temperature constant of pilot-gas drip catcher is at 85～95 ℃, and gas trap is connected on the boiler to capture flue gas, on gas trap, is connected with the gas absorption bottle, is contained with in the gas absorption bottle to be used to absorb SO ₂The H of gas ₂O ₂Solution, said H ₂O ₂The mass percentage concentration of solution is 1%～3%;

(2) open aspiration pump, extract the flue gas in the boiler, the control speed of exhaust is 3～5L/min, and the gas sample volume is V, and the pressure of gas meter is Pm, and the temperature of gas meter is t;

(3) after sampling finished, using pH value was the flue gas on 5～6 the sulfuric acid solution flushing gas drip catcher, collection washing fluid, SO ₂Gas is by H ₂O ₂The solution absorption liquid that is absorbed;

(4) using the dobell's solution titration washing fluid of 0.02mol/L is 5.5 up to pH, calculates SO through following formula ₃Concentration SO ₃(ppm):

${\mathrm{SO}}_3\left(\mathrm{ppm}\right)=\frac{0.224\×a\×f}{V\×\frac{273}{273+t}\×\frac{\mathrm{Pa}+\mathrm{Pm}-\mathrm{Pv}}{760}}\×1000\left(\mathrm{ppm}\right),$

Wherein, the volume of the 0.02mol/L dobell's solution that a=consumes, unit is ml;

F=2, promptly concentration is the factor of the sodium borate of 0.02mol/L;

V=gas sample volume, unit are L;

T=gas meter temperature, unit is ℃;

Pa=atmospheric pressure, unit are mmHg;

Pm=gas meter pressure, unit are mmHg;

Water saturation vapour pressure under the Pv=gas meter temperature, unit is mmHg;

(5) adopt precipitation titration to analyze the SO in the absorption liquid ₂Concentration, draw SO ₂Concentration SO ₂(ppm): the absorption liquid of getting 5～25ml is put into conical flask; Add 35～50ml isopropyl alcohol, 0.5～2ml acetate adds 3～5 indicator arsenazo III solution; Present blueness with the barium acetate solution titration absorption liquid of 0.05mol/L again and do not decorporate, calculate SO through following formula again ₂Concentration,

${\mathrm{SO}}_2\left(\mathrm{ppm}\right)=\frac{{\mathrm{afV}}_l/V_s}{V_g\frac{273}{273+t}\frac{\mathrm{Pa}+\mathrm{Pm}-\mathrm{Pv}}{760}}\·1000,$

Wherein, the volume of the 0.05mol/L barium acetate that a=consumes, unit is ml;

F=1.12 is the factor of 0.05mol/L barium acetate;

V ₁The cumulative volume of=absorption liquid, unit are ml;

V _sThe absorption liquid volume that=titration is used, unit is ml;

V _g=gas sample volume, unit are 1;

T=gas meter temperature, unit is ℃;

Pa=atmospheric pressure, unit are mmHg;

Pm=gas meter pressure, unit are mmHg;

Water saturation vapour pressure under the Pv=gas meter temperature, unit is mmHg;

(6) SO ₂The mensuration of oxygenation efficiency: adopt following formula to calculate SO ₂Oxygenation efficiency η SO ₂,

${\mathrm{\η}}_{{\mathrm{SO}}_2}(\%)=\frac{{\mathrm{SO}}_3\left(\mathrm{ppm}\right)}{{\mathrm{SO}}_2\left(\mathrm{ppm}\right)+{\mathrm{SO}}_3\left(\mathrm{ppm}\right)}\×100.$