CN103446870A - Desulfurization additive as well as applications and using method of same - Google Patents

Abstract

The invention relates to the field of chemical industry, and particularly relates to a desulfurization additive as well as applications and a using method of the same. The desulfurization additive contains the following raw materials in parts by weight: 30-40 parts of accelerant, 50-60 parts of activator and 5-15 parts of catalyst. The desulfurization additive can be used in a wet-process flue gas desulfurization technology of limestone or limestone gypsum. The using method of the desulfurization additive comprises the steps of: adding the desulfurization additive in a circulation loop of a limestone wet-process desulfurization circulation system; stirring; and adding the desulfurization additive by a set frequency. The desulfurization additive is capable of enhancing the reaction rate of desulfurization.

Description

Sulfur-removing additives, purposes and using method

Technical field

The present invention relates to chemical field, in particular to sulfur-removing additives, purposes and using method.

Background technology

In numerous flue gas desulfurization techniques, wet process of FGD is always in occupation of leading position, at present in the world in built desulfurizer, wet desulphurization device accounts for 80%, although the technical maturity of Wet Flue Gas Desulfurization Technique, desulfuration efficiency is high, but it also exists that initial investment is large, operating cost is high and the deficiency such as the easy fouling of equipment, obstruction, so people usually adopt and optimize desulfurization operations than the measure of the limestone particle of small particle diameter, improve the utilization rate of desulfurizing agent, and then reduce running cost.But still there is the poor problem of desulfurized effect in this mode.

Summary of the invention

The object of the present invention is to provide method and apparatus, to solve the above problems.

The embodiment of the present invention provides a kind of sulfur-removing additives, and its raw material comprises: according to the mass fraction, and 30-40 part promoter, 50-60 part activator, 5-15 part catalyst.

The embodiment of the present invention also provides a kind of purposes of above-mentioned sulfur-removing additives, for lime stone or lime stone-gypsum wet fuel gas desulfurizing technology.

The embodiment of the present invention also provides a kind of using method of above-mentioned sulfur-removing additives, comprising:

Sulfur-removing additives is added in the closed circuit of the Wet Limestone Desulfurization circulatory system;

Stir;

Add described sulfur-removing additives with setpoint frequency.

The sulfur-removing additives that the embodiment of the present invention provides, purposes and using method can reach following beneficial effect:

The principle of sulfur-removing additives in Wet Limestone Desulfurization is:

SO ₂+ H ₂o → H ₂sO ₃→ H ⁺+ HSO ₃absorption reaction

2HSO ₃+ O ₂→ 2SO ₄ ^2-+ 2H ^-oxidation reaction

CaCO ₃+2H ⁺→Ca ²⁺+H ₂O+CO ₂

Ca ²⁺+ SO ₄ ^2-+ 2H ₂o → CaSO ₄2H ₂the O crystallization

Catalyst in sulfur-removing additives changes the ionic equilibrium of slurries in desulfurizing tower, the reinforcing desulfuration process, and the metal ion in sulfur-removing additives has catalytic action to desulphurization reaction simultaneously, and the pH value that can cushion slurries descends, and promotes SO ₂dissolving, accelerate SO ₂absorption, improve chemical reaction and mass transport process, promote CaCO ₃dissolving; Activating agent can improve the reactivity of slurries, improves the reaction rate of desulfurization, effective.

The accompanying drawing explanation

Fig. 1 shows in an embodiment and adds absorption tower, sulfur-removing additives front and back desulfuration efficiency comparison diagram;

Fig. 2 shows in an embodiment and adds sulfur-removing additives front and back absorption tower entrance SO ₂the concentration comparison diagram;

Fig. 3 shows and adds the conversion ratio of agstone after sulfur-removing additives and be worth over time;

Fig. 4 shows and adds the conversion ratio of agstone after sulfur-removing additives and be worth over time.

The specific embodiment

Below by specific embodiment, also by reference to the accompanying drawings the present invention is described in further detail.

The embodiment of the present invention provides a kind of sulfur-removing additives, and its raw material comprises: according to the mass fraction, and 30-40 part promoter, 50-60 part activator, 5-15 part catalyst.

The embodiment of the present invention also provides a kind of purposes of above-mentioned sulfur-removing additives, for lime stone or lime stone-gypsum wet fuel gas desulfurizing technology.

The embodiment of the present invention also provides a kind of using method of above-mentioned sulfur-removing additives, comprising:

Sulfur-removing additives is added in the closed circuit of the Wet Limestone Desulfurization circulatory system;

Stir;

Add described sulfur-removing additives with setpoint frequency.

The principle of sulfur-removing additives in Wet Limestone Desulfurization is:

SO ₂+ H ₂o → H ₂sO ₃→ H ⁺+ HSO ₃absorption reaction

2HSO ₃+ O ₂→ 2SO ₄ ^2-+ 2H ^-oxidation reaction

CaCO ₃+2H ⁺→Ca ²⁺+H ₂O+CO ₂

Ca ²⁺+ SO ₄ ^2-+ 2H ₂o → CaSO ₄2H ₂the O crystallization

Catalyst in sulfur-removing additives changes the ionic equilibrium of slurries in desulfurizing tower, the reinforcing desulfuration process, and in sulfur-removing additives, the metal ion of promoter has catalytic action to desulphurization reaction simultaneously, and the pH value that can cushion slurries descends, and promotes SO ₂dissolving, accelerate SO ₂absorption, improve chemical reaction and mass transport process, promote CaCO ₃dissolving; Activating agent can improve the reactivity of slurries, improves the reaction rate of desulfurization, effective.

Next, the present invention will describe this sulfur-removing additives in detail by some specific embodiments:

In certain embodiments, the raw material of this sulfur-removing additives comprises: according to the mass fraction, and 30 parts of promoter, 50 parts of activators, 5 parts of catalyst.

In one embodiment, the raw material of this sulfur-removing additives comprises: according to the mass fraction, and 35 parts of promoter, 55 parts of activators, 10 parts of catalyst.

In certain embodiments, the raw material of this sulfur-removing additives comprises: according to the mass fraction, and 40 parts of promoter, 60 parts of activators, 15 parts of catalyst.

Wherein promoter comprise following one or more: NaCl, CaCl ₂, MgSO ₄, MgO, AlSO ₄, the metal ion of promoter has catalytic action to desulphurization reaction, and the pH value that can cushion slurries descends, and promotes SO ₂dissolving, accelerate SO ₂absorption, improve chemical reaction and mass transport process, promote CaCO ₃dissolving; Activator comprise following one or more: adipic acid, glutaric acid, succinic acid, acrylic acid, acetic acid, M-phthalic acid, activating agent can improve the reactivity of slurries, improves the reaction rate of desulfurization; Catalyst comprises: sulfosuccinic acid di-isooctyl sodium, catalyst changes the ionic equilibrium of slurries in desulfurizing tower, reinforcing desulfuration process.This sulfur-removing additives is mainly used in lime stone or lime stone-gypsum sulfur removal technology.

The sulfur-removing additives of take is example for limestone desulfurization technique: in when limestone desulfurization technique is added sulfur-removing additives, adding sulfur-removing additives the closed circuit of the Wet Limestone Desulfurization circulatory system to, in certain embodiments, melt pit in this closed circuit is reasonable point of addition, sulfur-removing additives can enter in absorption tower with slurries, add in sulfur-removing additives and will be held open agitator, guarantee that the dissolving of sulfur-removing additives and diffusion are even.Then supplemented and add once according to every 12 to 24 hours.And, detect at any time the SO of Wet Limestone Desulfurization circulatory system gas discharge outlet ₂content or clean flue gas in SO ₂content; SO when Wet Limestone Desulfurization circulatory system gas discharge outlet ₂content ascending amount while surpassing the first preset value, add described sulfur-removing additives; SO in clean flue gas ₂content while surpassing the second preset value, add described sulfur-removing additives.While adding sulfur-removing additives for the first time, because dosage is larger, prevent that absorption tower melt pit serum density is excessive, degree of adding be controlled at 400-1000ppm(such as, adopt 600ppm in some embodiment, or 850ppm), prevent agitator and sump pump overcurrent trip.

Operating personnel, in adding procedure, pay close attention to thionizer liquid level, density, pH value, especially liquid level, and after preventing that sulfur-removing additives from adding, slurries bubble, and form false liquid level, cause desulfurizing tower completely to starch, and the desulfurizing tower liquid level of slurry can not surpass setting;

3, add in the sulfur-removing additives operating process, take care, prevent the generation of personal safety accident.

The concrete using method of sulfur-removing additives:

1. stable operation of unit, used sulfur-removing additives according to testing program, and desulphurization system is carried out the operation monitoring adjustment according to the operating standard regulation, records the desulphurization system service data.

2. coal-fired sulfur is determined by upper coal situation, slightly fluctuation, and the entrance sulfur dioxide concentration can be higher than the former design upper limit of desulphurization system 20% left and right, oepration at full load, can embody test requirements document, in process of the test, keep load constant as far as possible, guarantee to add sulfur-removing additives front and back systematic parameter and there is comparativity.

3., before adding, absorption tower melt pit liquid level is reduced to 0.5m.

4. calculate according to the interpolation concentration of 400ppm-1000ppm, add first sulfur-removing additives in melt pit, and stir and squeeze in absorption tower by sump pump in 10-15 minute.

5. absorption tower keeps normal for slurry, and pH value is controlled in the 5.3-6.2 scope.

6. observe each parameter and change, when pH value remains stable, desulfuration efficiency improves, and illustrates that sulfur-removing additives plays a role.(time of sulfur-removing additives reaction is generally and adds rear half an hour).

7. strengthen the oxidation fan air quantity.(sulfur-removing additives has improved the absorption tower desulphurizing ability after adding, the calcium sulfite simultaneously generated increases)

8. stable the reaching of test dropped into sulfur-removing additives once every day in later stage.

(1) at desulfurizing tower entrance SO ₂concentration is the former design of desulphurization system when following, adds 100-150 kilogram sulfur-removing additives every day.

(2) at desulfurizing tower entrance SO ₂concentration when being greater than the former design of desulphurization system, adds 150-200 kilogram sulfur-removing additives every day.

It should be noted that: ppm is the abbreviation of English parts permillion, translating meaning and be every hundred parts in very much, means 1,000,000/(several), or claims PPM.As 1ppm contains 1 kilogram of solute in the solution of 100 kilograms.The ppm content represented with percentage (%) is the same, and just its proportional numbers is larger than percentage.

In process of the test, the Power Generation Section personnel are put into central station of floating dock to the detection data after sampling and perform an analysis to the laboratory technician every days.

Points for attention in process of the test

1. should slowly add during to absorption tower melt pit dosing, guarantee that medicine stirs.To beat to minimum liquid level when each absorption tower sump pump moves, guarantee that liquid all enters absorption tower.

2. test and within first 1 hour, should arrange desulfurization operation branch company to reduce by 0.5 meter of absorbing tower liquid-level, in order to receive the slurries in the melt pit of absorption tower.

3. after adding additive, desulfuration efficiency may obviously rise, and gypsum slurries pH value slight situation about reducing in absorption tower easily occurs, and requires desulfurization operation branch company to maintain higher operation pH value (5.3-6.2) before additive adds.

4. duration of test, keep at least 3 days de-water of gypsum to get back in pilot system.If, when in lime stone slurry, chlorion surpasses 20000mg/L, can suitably efflux.While adding pharmaceutical quantities, this part be counted.

5. start to record the desulfurization operation data the previous day in experiment, in first two hours, every 10 minutes record data once, after 2 hours, each hour record data once.

6. for reaching optimal running effect, administration timing of drug can be taked every 12 hours once, and the chemical feeding quantities of 24 hours are separately got final product.

7. in concrete sulfur-removing additives use amount test implementation process, can adjust accordingly according to actual condition.

Sulfur-removing additives in above-described embodiment is applied in limestone desulfurization technique:

One: calculate the desulfuration efficiency improvement value

Get import and outlet (flue gas automatic monitored control system, CEMS) SO after the measurement conversion of tail gas desulfurization (FGD) device in wet desulphurization ₂concentration (the coal-burning boiler excess air coefficient gets 1.4).

The percentage of amount of sulfur dioxide calculates by formula (1).

In formula, SO ₂for 6%O is arrived in conversion ₂under concentration, SO _{2 actual measurements}, O _{2 actual measurements}be respectively actual measurement SO ₂concentration, O ₂concentration.As shown in Figure 2.

Desulfuration efficiency calculates by formula (2).

$\mathrm{\η}=\frac{{\mathrm{SO}}_{2\mathrm{FGDIN}}-{\mathrm{SO}}_{2\mathrm{FGDOUT}}}{{\mathrm{SO}}_{2\mathrm{FGDIN}}}\×100\%---\left(2\right)$

In formula, SO _2FGDIN, SO _2FGDOUTbe respectively the SO of desulfurization facility import and export ₂conversion concentration.

Calculate respectively the desulfuration efficiency η that uses the sulfur-removing additives front and back _before, η _after, by the difference of desulfuration efficiency before and after calculating, obtain the improvement value of desulfuration efficiency, as shown in Figure 1.

Two, the lime stone molten time shorten rate that partly disappears

Measure the CaCl of 250mL0.1mol/L with graduated cylinder ₂solution, inject beaker, and it is placed in water-bath, after controlling temperature 50 C and making its constant temperature, with electronic balance, takes the 0.15g agstone, adds in the beaker of constant temperature, and insert the paddle of agitator, and speed is 800r/min, continuous stirring 5min.The pH meter electrode is inserted in lime stone suspension, and the attention electrode is not encountered paddle.It is 5.5 that autotitrator is set the pH value, with the 0.1mol/L hydrochloric acid solution, starts titration, and stopwatch starts timing simultaneously, records not the hydrochloric acid solution consumption of t in the same time.

The conversion ratio of agstone calculates by formula (3).

$X\left(t\right)=\frac{\frac{1}{2}{c}_{\mathrm{HCl}}{V}_{\mathrm{HCl}}}{\frac{{\mathrm{W\ω}}_{{\mathrm{CaCO}}_3}}{M_r\left({\mathrm{CaCO}}_3\right)}+\frac{{\mathrm{W\ω}}_{{\mathrm{MgCO}}_3}}{M_r\left({\mathrm{MgCO}}_3\right)}}\×100\%...............\left(3\right)$

In formula: X(t)---t is the conversion ratio of agstone constantly;

C _hCl---the concentration of hydrochloric acid, mol/L;

V _hCl(t)---the hydrochloric acid volume that t titration constantly consumes, mL;

The quality of W---agstone, g;

ω _caCO3---the quality percentage of calcium carbonate in agstone is measured value;

ω _mgCO3---the quality percentage of magnesium carbonate in agstone is measured value;

M _r(CaCO ₃)---the molecular weight of calcium carbonate is 100;

M _r(MgCO ₃)---the molecular weight of magnesium carbonate is 40.

According to above formula result of calculation, take the time as permanent coordinate, conversion ratio is the ordinate curve plotting, as shown in Figure 3.

By identical analytical procedure and computational methods to using the lime stone after sulfur-removing additives to carry out analytical calculation, by identical method curve plotting, as shown in Figure 4.

Calculate the lime stone molten time shorten rate that partly disappears, can obtain using before and after sulfur-removing additives corresponding time when lime stone sample conversion ratio is 50% from Fig. 3 curve 1 and Fig. 4 curve 2, be respectively t ₁and t ₂, the lime stone molten time shorten rate that partly disappears is calculated by formula (4).

${\mathrm{\&eta;}}_0=\frac{t_1-t_2}{{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="HDA0000377860510000011.png,HDA0000377860510000012.png"\; state="\{\{state\}\}">t</figure-callout>}}_1}\&times;100\%---\left(4\right)$

Add this sulfur-removing additives, can obviously improve chemical reaction and mass transport process, can promote CaCO ₃dissolving, the pH value of buffering slurries descends, promotion SO ₂dissolving, accelerate SO ₂chemical absorbing.Can improve its desulfuration efficiency, can improve again the utilization rate of desulfurizing agent, and then reduce operating cost, can also slow down fouling and the obstruction of equipment simultaneously.

The foregoing is only preferred case study on implementation of the present invention, be not limited to the present invention, for a person skilled in the art, the present invention can have various modifications and variations.Within the spirit and principles in the present invention all, any modification of doing, be equal to replacement, improvement etc., within all should being included in protection scope of the present invention.

Claims (10)

1. a sulfur-removing additives, is characterized in that, its raw material comprises: according to the mass fraction, and 30-40 part promoter, 50-60 part activator, 5-15 part catalyst.

2. sulfur-removing additives according to claim 1, is characterized in that, its raw material comprises: according to the mass fraction, and 35 parts of promoter, 55 parts of activators, 10 parts of catalyst.

3. sulfur-removing additives according to claim 1 and 2, is characterized in that,

Described promoter comprise following one or more: NaCl, CaCl ₂, MgSO ₄, MgO, AlSO ₄.

4. sulfur-removing additives according to claim 1 and 2, is characterized in that,

Described activator comprise following one or more: adipic acid, glutaric acid, succinic acid, acrylic acid, acetic acid, M-phthalic acid.

5. sulfur-removing additives according to claim 1 and 2, is characterized in that,

Described catalyst comprises: sulfosuccinic acid di-isooctyl sodium.

6. the purposes of the described sulfur-removing additives of claim 1-5, is characterized in that, for lime stone or lime stone-gypsum wet fuel gas desulfurizing technology.

7. the using method of the described sulfur-removing additives of claim 1-5, is characterized in that, comprising:

Sulfur-removing additives is added in the closed circuit of the Wet Limestone Desulfurization circulatory system;

Stir;

Add described sulfur-removing additives with setpoint frequency.

8. using method according to claim 7, is characterized in that, when adding described sulfur-removing additives for the first time, addition is 400-1000ppm.

9. using method according to claim 7, is characterized in that,

Described setpoint frequency is 12-24 hour/time.

10. according to the described using method of claim 7-9 any one, it is characterized in that,

After in the described closed circuit that sulfur-removing additives is added to the Wet Limestone Desulfurization circulatory system, described using method also comprises: the SO that detects Wet Limestone Desulfurization circulatory system gas discharge outlet ₂content or clean flue gas in SO ₂content;

SO when Wet Limestone Desulfurization circulatory system gas discharge outlet ₂content ascending amount while surpassing the first preset value, add described sulfur-removing additives;

SO in clean flue gas ₂content while surpassing the second preset value, add described sulfur-removing additives.

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