CN103446870B - Sulfur-removing additives, purposes and using method - Google Patents

Abstract

The present invention relates to chemical field, in particular to sulfur-removing additives, purposes and using method.This sulfur-removing additives, its raw material comprises: according to the mass fraction, 30-40 part promoter, 50-60 part activator, 5-15 part catalyst.The purposes of this sulfur-removing additives, in lime stone or lime stone-gypsum wet fuel gas desulfurizing technology.The using method of this sulfur-removing additives, it comprises: added to by sulfur-removing additives in the closed circuit of the Wet Limestone Desulfurization circulatory system; Stir; Described sulfur-removing additives is added with setpoint frequency.The present invention can improve 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, in desulfurizer built in the world at present, wet desulphurization device accounts for 80%, although the technical maturity of Wet Flue Gas Desulfurization Technique, desulfuration efficiency is high, but it also also exists, and initial investment is large, operating cost is high and the deficiency such as the easy fouling of equipment, blocking, so people adopt measure compared with the limestone particle of small particle diameter to optimize desulfurization operations usually, improve the utilization rate of desulfurizing agent, and then reduce running cost.But still there is the problem of desulfurized effect difference in this mode.

Summary of the invention

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

Embodiments provide a kind of sulfur-removing additives, its raw material comprises: according to the mass fraction, 30-40 part promoter, 50-60 part activator, 5-15 part catalyst.

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

The embodiment of the present invention additionally 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;

Described sulfur-removing additives is added 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 ₂o crystallization

Catalyst in sulfur-removing additives changes the ionic equilibrium of slurries in desulfurizing tower, reinforcing desulfuration process, and the metal ion simultaneously in sulfur-removing additives has catalytic action to desulphurization reaction, and the pH value that can cushion slurries declines, 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.

Accompanying drawing explanation

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

Fig. 2 shows in an embodiment and adds entrance SO in absorption tower before and after sulfur-removing additives ₂concentrations versus figure;

After Fig. 3 shows and adds sulfur-removing additives, the conversion ratio of agstone is worth over time;

After Fig. 4 shows and adds sulfur-removing additives, the conversion ratio of agstone is worth over time.

Detailed description of the invention

Also by reference to the accompanying drawings the present invention is described in further detail below by specific embodiment.

Embodiments provide a kind of sulfur-removing additives, its raw material comprises: according to the mass fraction, 30-40 part promoter, 50-60 part activator, 5-15 part catalyst.

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

The embodiment of the present invention additionally 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;

Described sulfur-removing additives is added 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 ₂o crystallization

Catalyst in sulfur-removing additives changes the ionic equilibrium of slurries in desulfurizing tower, 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 declines, 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, 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, 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, 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 declines, 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, and 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.

Limestone desulfurization technique is used for: add in the closed circuit of the Wet Limestone Desulfurization circulatory system when adding sulfur-removing additives in limestone desulfurization technique by sulfur-removing additives for sulfur-removing additives, 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 the dissolving of sulfur-removing additives and spread evenly.Then supplemented according to every ten two to two ten four hours and add once.And, the SO of Wet Limestone Desulfurization circulatory system gas discharge outlet will be detected at any time ₂content or neat stress in SO ₂content; As the SO of Wet Limestone Desulfurization circulatory system gas discharge outlet ₂content ascending amount more than the first preset value time, add described sulfur-removing additives; As SO in neat stress ₂content more than the second preset value time, add described sulfur-removing additives.First time, when adding sulfur-removing additives, because dosage is comparatively large, prevents absorption tower melt pit serum density excessive, degree of adding controls at 400-1000ppm(such as, 600ppm is adopted in some embodiments, 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 sulfur-removing additives from adding, slurries bubble, and form false liquid level, cause desulfurizing tower completely to starch, Desulfurization tower slurry liquid level can not exceed setting;

3, add in 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, uses sulfur-removing additives according to testing program, and desulphurization system carries out operation monitoring adjustment according to operating standard regulation, record desulphurization system service data.

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

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

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

5. absorption tower keeps normal for slurry, and pH value controls within the scope of 5.3-6.2.

6. observe each Parameters variation, 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 oxidation fan air quantity.(sulfur-removing additives improves absorption tower desulphurizing ability after adding, and the calcium sulfite simultaneously generated increases)

8. test is stablized and is dropped into sulfur-removing additives once every day in later stage.

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

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

It should be noted that: ppm is the abbreviation of English partspermillion, translating meaning be every hundred very much in a part, namely represent 1,000,000/(several), or claim PPM.As contained 1 kilogram of solute in the 1ppm i.e. solution of 100 kilograms.Ppm is the same with the content represented by percentage (%), and just its proportional numbers is larger than percentage.

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

Points for attention in process of the test

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

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

3. after adding additive, desulfuration efficiency may obviously rise, and the situation that absorption tower gypsum slurries pH value slightly reduces easily occurs, requires the operation pH value (5.3-6.2) that desulfurization operation branch company remains higher before additive adds.

4. duration of test, keeps the de-water of at least 3 days gypsum to get back in pilot system.If when in lime stone slurry, chlorion is more than 20000mg/L, can arrange suitably outward.When adding pharmaceutical quantities, this part be counted.

5. daystart record desulfurization operation data on pretreatment, 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 take every 12 hours once, by the chemical feeding quantity of 24 hours separately.

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

Be applied in limestone desulfurization technique to the sulfur-removing additives in above-described embodiment:

One: calculate desulfuration efficiency improvement value

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

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

In formula, SO ₂for conversion is to 6%O 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 equipment import and export ₂conversion concentration.

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

Two, lime stone partly disappears molten time shorten rate

The CaCl of 250mL0.1mol/L is measured with graduated cylinder ₂solution, injects beaker, and it is placed in a water bath, and control temperature 50 DEG C also, after making its constant temperature, takes 0.15g agstone with electronic balance, adds in the beaker of constant temperature, and inserts the paddle of agitator, and speed is 800r/min, stirs 5min continuously.PH meter electrode is inserted in lime stone suspension, notices that electrode does not encounter paddle.Autotitrator setting pH value is 5.5, and start titration with 0.1mol/L hydrochloric acid solution, 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)---the conversion ratio of t agstone;

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

V _hCl(t)---the hydrochloric acid volume that t titration 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, with the time for permanent coordinate, conversion ratio is ordinate curve plotting, as shown in Figure 3.

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

Calculate lime stone partly to disappear molten time shorten rate, can obtain using the time corresponding when lime stone sample conversion ratio is 50% before and after sulfur-removing additives 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 calculates by formula (4).

${\mathrm{\η}}_0=\frac{t_1-t_2}{t_1}\×100\%---\left(4\right)$

Add this sulfur-removing additives, can obviously improve chemical reaction and mass transport process, can CaCO be promoted ₃dissolving, buffering slurries pH value decline, promote SO ₂dissolving, accelerate SO ₂chemical absorbing.Its desulfuration efficiency can be improved, the utilization rate of desulfurizing agent can be improved again, and then reduce operating cost, fouling and the blocking of equipment can also be slowed down 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 amendment done, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (3)

1. a using method for sulfur-removing additives, is characterized in that, comprising:

Absorption tower melt pit liquid level is reduced 0.5m;

Sulfur-removing additives is added in the melt pit of absorption tower, stir in adition process;

Absorption tower keeps normal for slurry, and pH value controls 5.3 ~ 6.2;

Strengthen oxidation fan amount;

Supplement according to the interpolation frequencies of 12 ~ 24 hours/time and add sulfur-removing additives;

According to the mass fraction, described sulfur-removing additives comprises: 30-40 part promoter, 50-60 part activator, 5-15 part catalyst;

Described promoter comprise following one or more: CaCl ₂, MgO, AlSO ₄;

Described activator comprise following one or more: acrylic acid, acetic acid;

Described catalyst comprises: sulfosuccinic acid di-isooctyl sodium.

2. using method according to claim 1, is characterized in that, when first time adds described sulfur-removing additives, addition is 400-1000ppm.

3. the using method according to any one of claim 1-2, is characterized in that,

Described sulfur-removing additives is added in the closed circuit of the Wet Limestone Desulfurization circulatory system after, described using method also comprises: the SO detecting Wet Limestone Desulfurization circulatory system gas discharge outlet ₂content or neat stress in SO ₂content;

As the SO of Wet Limestone Desulfurization circulatory system gas discharge outlet ₂content ascending amount more than the first preset value time, add described sulfur-removing additives;

As SO in neat stress ₂content more than the second preset value time, add described sulfur-removing additives.