CN205323522U - Flue gas desulfurization denitration integration equipment of multivariable control - Google Patents

Abstract

The utility model provides a flue gas desulfurization denitration integration equipment of multivariable control, includes process parameter detection device, process parameter adjusting device and computer control system, computer control system connects above -mentioned each parameter detecting device and parameter adjustment device, receives each detection device's process parameter signal, moves SOx/NOx control process multivariable control algorithm and exports control signal to each adjusting device. Through the utility model discloses an equipment can improve SOx/NOx control control accuracy, reduces the running cost, and the SOx/NOx control index of the emission flue gas that big skewing, large inertia and the various inside disturbance of overcoming the SOx/NOx control process caused is undulant, realizes environmental protection index card edge domination.

Description

The flue gas desulfurization and denitrification integration apparatus of multivariable Control

Technical field

This utility model relates to combustion product gases desulphurization denitration field, relates more specifically to the flue gas desulfurization and denitrification integration apparatus of a kind of multivariable Control。

Background technology

Combustion process is to provide the Main Means of heat energy, is widely present in the industrial production。But the produced flue gas of burning often contains SO₂With nitrogen oxides NO_x, these compositions are important atmosphere pollutions, can cause acid rain, haze, chemical fumes, and the mankind, animal, plant and building, facility are had long-term infringement。

Desulphurization denitration is that combustion product gases processes, reduces SO₂With nitrogen oxides NO_xThe important technical of discharge。The technique of desulphurization denitration is a lot, and wet-type ammonia forced turbulent desulfurization, pressure oxidation carbamide denitrification integral process are one of which (as shown in Figure 1)。The equipment that the method comprises includes: air-introduced machine, heat recovery boiler, booster fan, desulfurizing tower, denitrating tower, ammonium sulfate circulating slot, solid-liquid separator, dehydrogenation drying equipment, urea liquid storage tank and the auxiliary equipment such as pipeline and circulating pump。The externally input medium that the method relates to includes: (1) flue gas；(2) ammonia；(3) ozone；(4) deaerated water；(5) fresh water (FW)；(6) sulfite oxidation compression air。The output medium that this method relates to includes: (1) meets the qualified discharge flue gas of environmental requirement；(2) ammonium sulfate solids；(3) low-pressure steam。

Flue gas sends into heat recovery boiler through air-introduced machine, and flue-gas temperature is down to about 160 DEG C, Mist heat recovering output steam；Flue gas after waste heat recovery is through booster fan, through flue gas input channel, converges with ozone input channel before entering desulfurizing tower, the NO (part) in flue gas and ozone fast reaction, generates NO₂, flue gas sends into desulfurizing tower enriching section after mixing with ozone。

In enriching section, the solution of the liquid containing ammonium sulfate sent here through circulating pump from ammonium sulfate circulating slot is from enriching section top spray, heat smoke counter current contacting with about 160 DEG C evaporates the moisture in spray liquid, it is achieved the concentration of ammonium sulfate, and enriching section bottom liquid delivers to ammonium sulfate circulating slot。Through spray-evaporation-concentration repeatedly, the ammonium sulfate solid content in ammonium sulfate storage tank being brought up to more than 5%, discharging is to solid-liquid separation, and through drying and dehydrating, output ammonium sulfate solids, packaging is transported outward。The mother solution obtained after solid-liquid separation, is back to desulfurizing tower reservoir。After completing discharging, from desulfurizing tower reservoir, liquid storage delivered to ammonium sulfate circulating slot every time。Flue-gas temperature through enriching section is down to about 65 DEG C from 160 DEG C, enters into the absorber portion of desulfurizing tower through gas piping (such as gas cap), and the desulfurization with top spray absorbs liquid, and (effective ingredient is (NH₄)₂SO₃) counter current contacting, under the great turbulence level state that booster fan is formed, complete mass transfer desulfurization, the reaction equation of desulfurization: (NH₄)₂SO₃+SO₂+H₂O=2 (NH₄)HSO₃, the NO in flue gas simultaneously₂With NO with from the bottom of denitrating tower tower containing carbamide residual liquid counter current contacting, it is achieved pre-denitration, denitration reaction equation: CO (NH₂)₂+NO₂+ NO=CO₂+3N₂+2H₂O。Liquid bath liquid bottom absorber portion is back to the reservoir bottom desulfurizing tower。In order to recover to absorb the absorbability of liquid, add and supplement ammonia (content about 10%), reaction equation: (NH₄)HSO₃+(NH₄) OH=(NH₄)₂SO₃+H₂O。The pH value absorbing liquid controls about 5.5。Desulfurizing tower top can spray process water, keep reservoir liquid level in the reasonable scope。Air is blasted, by the part (NH in reservoir bottom reservoir₄)₂SO₃It is oxidized to (NH₄)₂SO₄, reaction equation: 2 (NH₄)₂SO₃+O₂=2 (NH₄)SO₄。The enriching section directed the air into by air line between reservoir and enriching section, regulates air capacity and air pressure, changes the degree of oxidation。

Flue after desulfurization tower top desulfurization is connected with ozone input channel, ozone mixed in the flue gas of about 60 DEG C after desulfurization, the NO (part) in flue gas and ozone fast reaction, generates NO₂, control NO₂It is 1: 1 with the ratio of NO。Flue gas enters denitrating tower bottom, and the urea liquid counter current contacting of denitrating tower top spray, completes denitration。Denitration reaction equation: CO (NH₂)₂+NO₂+ NO=CO₂+3N₂+2H₂O。Bottom denitrating tower, residual liquid is pumped to top repeatedly by circulating pump, suitably replenishes new urea liquid to keep the urea concentration of denitration absorbing liquor more than 10%。Part residual liquid bottom denitrating tower delivers to desulfurizing tower top spray, it is achieved the excessive moisture that denitration produces also is supplemented to desulfurizing tower by pre-denitration。Through desulphurization and denitration, the flue gas reaching environmental emission standard enters air at denitrating tower top, completes whole processing procedures of flue gas。

The control target of this desulphurization denitration process is the SO in the flue gas after making process₂With nitrogen oxides NO_xContent meet the discharge index that national environmental standard requires, and can adapt to the change of exhaust gas volumn load, smoke components fluctuation and the internal various operating characteristics (resistance, mass-transfer efficiency, valve performance etc.) of desulfuring and denitrifying apparatus。

But adopt this device to carry out the process of emission, often due to smoke components and flow change or built-in system exists various disturbance, corresponding procedure parameter still keeps original setting value, cause that the reactant added too much increases cost or very few and inabundant desulphurization denitration, make the SO in the flue gas after process₂With nitrogen oxides NO_xContent can not meet the discharge index that national environmental standard requires。

Utility model content

In view of this, the purpose of this utility model is in that to design the flue gas desulfurization and denitrification integration apparatus of a kind of multivariable Control, as preferably, this integration apparatus can improve desulphurization denitration control accuracy, reduce operating cost, overcome the desulphurization denitration index fluctuation discharging flue gas that the large dead time of desulphurization denitration process, big inertia and various internal disturbance cause, it is achieved environmental protection index bounder control。

For achieving the above object, the utility model proposes the flue gas desulfurization and denitrification integration apparatus of a kind of multivariable Control, described flue gas desulfurization and denitrification integration apparatus includes booster fan, desulfurizing tower, denitrating tower, and Detection of Process Parameters device, procedure parameter regulate device and computer control system, wherein

Described Detection of Process Parameters device contains desulfurizing tower inlet flue gas component detection apparatus and denitrating tower exiting flue gas component detection apparatus, and containing more than one devices in booster fan outlet pressure detecting device, desulfurizing tower entrance flow of ozone amount detecting device, denitrating tower entrance flow of ozone amount detecting device；

Described procedure parameter regulates that device comprises that booster fan outlet pressure regulates device, desulfurizing tower entrance flow of ozone quantity regulating device, denitrating tower entrance flow of ozone quantity regulating device, doctor solution circular flow regulate device, denitration liquid circular flow regulates device and denitrating tower column bottoms pump and delivers to the two or more devices in the denitration liquid flow regulator of desulfurizing tower tower top；

Described computer control system connects described each Detection of Process Parameters device and procedure parameter regulates device, receive the process parameter signals of described each Detection of Process Parameters device output, run desulphurization denitration process multivariable Control algorithm and regulate device output control signal to each described procedure parameter。

According to a kind of detailed description of the invention of the present utility model, Detection of Process Parameters device farther includes disturbance feedforward detecting device, and described disturbance feedforward detecting device includes desulfurizing tower reservoir pH value measurement apparatus and/or denitration liquid urea content detecting device。

According to a kind of detailed description of the invention of the present utility model, flue gas desulfurization and denitrification integration apparatus is wet-type ammonia forced turbulent desulfurization, forces oxidation carbamide denitrification integral equipment。

According to a kind of detailed description of the invention of the present utility model, Detection of Process Parameters device farther includes at least one device in liquid level detection device, ammonium sulfate circulating slot liquid level detection device, desulfurizing tower reservoir gravity detecting device, ammonium sulfate circulating slot at the bottom of desulfurizing tower reservoir oxidation air entrance wind pressure detection device, denitration tower bottoms amount detecting device, desulfurizing tower reservoir liquid level detection device, denitrating tower tower in liquid specific gravity detecting device and doctor solution pH value detecting device。

According to a kind of detailed description of the invention of the present utility model, procedure parameter adjustment device farther includes ammonium sulfate and follows ammonium concentration cycles pump adjustment device and/or ammonia aqua stream quantity regulating device。

Based on technique scheme it can be seen that flue gas desulfurization and denitrification integration apparatus of the present utility model has the advantages that

(1) by the control mode containing computer system, it is achieved automatically controlling of desulfuring and denitrifying apparatus, the SO in the flue gas after desulfurizing and denitrifying process flow processing is made₂With nitrogen oxides NO_xContent meet the discharge index restriction that national environmental standard requires, overcome exhaust gas volumn, smoke components to fluctuate, and various internal disturbance；

(2) by parameter being sampled in the sampling period, detect disturbance parameter, timely process parameters, it is achieved the running optimizatin of desulfuring and denitrifying apparatus, reduce ozone usage and booster fan power consumption, reduce plant running cost；

(3) by setting the rational sampling period, overcome the impact of the big inertia large time delay of desulphurization denitration process better, improve control accuracy；

(4) by arranging survey disturbance feedforward feedback device, each parameter can be controlled more accurately and control the SO of final flue gas₂Content and nitrogen oxides NO_xContent。

Accompanying drawing explanation

Fig. 1 is the schematic diagram of a kind of desulfurizing and denitrifying process in prior art；

Fig. 2 is the control flow chart of the flue gas desulfurization and denitrification integration apparatus of multivariable Control。

Detailed description of the invention

For making the purpose of this utility model, technical scheme and advantage clearly understand, below in conjunction with specific embodiment, and with reference to accompanying drawing, the utility model is described in further detail。

Embodiment

As in figure 2 it is shown, in desulfurization and denitrification integral equipment of the present utility model, relate to the relevant of control mode and be provided that

First, Detection of Process Parameters instrument: desulfurizing tower entrance flow of ozone amount detecting device I1；The flow of ozone amount detecting device I2 of denitrating tower entrance；Doctor solution circulating load detecting device I3；Denitration liquid circulating load detecting device I4；Denitration liquid urea content detecting device I5；Booster fan outlet pressure detecting device I6；Desulfurizing tower inlet flue gas component detection apparatus I7 (includes NO, NO₂And SO₂Composition)；Desulfurizing tower reservoir oxidation air entrance wind pressure detection device I8；The denitration tower bottoms amount detecting device I9 at pumping value desulfurizing tower top；Component detection apparatus I10 (the NO of denitrating tower top discharge flue gas_xAnd SO₂)；Desulfurizing tower reservoir liquid level detection device I11；Liquid level detection device I12 at the bottom of denitrating tower tower；Ammonium sulfate circulating slot liquid level detection device I13；Desulfurizing tower reservoir gravity detecting device I14；Liquid specific gravity detecting device I15 in ammonium sulfate circulating slot；Doctor solution pH value detecting device I16。

It addition, integrated apparatus is arranged regulates device as follows: booster fan rotating speed frequency conversion adjustment device for high C1；Desulfurizing tower entrance flow of ozone adjustable valve C2；Denitrating tower entrance flow of ozone adjustable valve C3；Doctor solution circulating pump variable frequency adjustment or adjustment valve C4；Denitration liquid circulating pump variable frequency adjustment or adjustment valve C5；Desulfurizing tower reservoir oxidation air fan frequency conversion regulates device C6；Tail pump at the bottom of denitrating tower is delivered to desulfurizing tower top circulating pump variable frequency adjustment or regulates valve C7；Ammonium sulfate follows ammonium concentration cycles pump frequency conversion and regulates or regulate valve C8；Ammonia aqua stream adjustable valve C9。

Integrated apparatus arranges computer control system, controller (such as PID controller) accesses set Detection of Process Parameters signal and regulates signal, run desulphurization denitration process multivariable Control algorithm, carry out the Real-time Collection of process parameter signals and control to calculate, and sending control signal regulates the operation of device。Multivariable Control is with multiple single loop closed loop controls for generalized object, with basis loop settings value for controlling input, with the SO of denitrating tower top discharge flue gas₂Content and nitrogen oxides NO_xContent, for controlling output, feedovers with measurable disturbance。

Above-mentioned base control loop includes shown in table 1:

Table 1

The above-mentioned feedforward includes shown in table 2:

Table 2

Using the setting value in each base control loop as the input of generalized object, with the NO in denitrating tower top discharge flue gas_xContent and SO₂Content is generalized object output, for this multivariable process, implements multivariable Control, with the impact of the big inertia of large dead time of the coupling and desulphurization denitration process that eliminate process internal。

Multivariable Control algorithm adopts the kinetic model of desulphurization denitration process, model can adopt parametric form (transmission function, difference equation etc.) or nonparametric form (step response, impulse response etc.) or model of mind (neutral net, fuzzy model etc.), and the purpose of model is in that to realize the prediction of process output in future。Model prediction structure is as follows:

$\left[\begin{array}{c}CV1\\ CV2\end{array}\right]=\left[\begin{array}{cccccc}{M}_{11}& M_{12}& M_{13}& M_{14}& M_{15}& M_{16}\\ M_{21}& M_{22}& M_{23}& M_{24}& M_{25}& M_{26}\end{array}\right]\·\left[\begin{array}{c}MV1\\ MV2\\ MV3\\ MV4\\ MV5\\ MV6\end{array}\right];$

For step response test, only changing a Generalized Control input, it is constant that other input is maintained at present operating point, the output of record generalized object, i.e. NO in denitrating tower top discharge flue gas every time_xContent and SO₂Content, using input and output and the difference of steady operation point as step response model。By repeatedly testing, eliminate the impact of data noise and disturbance。For MV1 to MV6, the step response model of desulfuring and denitrifying apparatus just can be set up in this way。

Multivariable Control algorithm adopts PREDICTIVE CONTROL, to overcome the large time delay of desulphurization and denitration process, meets and runs constraints, and realize bounder control。Sampling (control) cycle meets the sampling thheorem requirement of the most fast process variable of desulphurization denitration, it was predicted that time domain is more than the process transitions time of the most slow process of desulphurization denitration。Described the fastest and most slow process can be determined according to desulphurization denitration process kinetics model, it was predicted that the control time domain of control with predict that time domain is identical。

The object function of the PREDICTIVE CONTROL involved by multivariable Control comprises three factors: (1) discharge flue gas NO_xContent and SO₂The actual value of content and the deviation of desired value；(2) desulfurizing tower entrance ozone dosage；(3) denitrating tower entrance ozone dosage；(4) booster fan pressure。

The mathematical description of umlti-variable finite elements is as follows:

$\begin{array}{c}\min J=W_{cv1}\underset{i=1}{\overset{P}{\Σ}}{\[CV{1}_{sp}-CV1\left(i\right)\]}^2+W_{cv2}\underset{i=1}{\overset{P}{\Σ}}{\[CV{2}_{sp}-CV2\left(i\right)\]}^2\\ +W_{I1}\underset{i=1}{\overset{P}{\Σ}}Ii{\left(i\right)}^2+W_{I2}\underset{i=1}{\overset{P}{\Σ}}I2{\left(i\right)}^2+W_{I6}\underset{i=1}{\overset{P}{\Σ}}I6{\left(i\right)}^2\end{array}$

$\left[\begin{array}{c}CV1\\ CV2\end{array}\right]=\left[\begin{array}{cccccc}{M}_{11}& M_{12}& M_{13}& M_{14}& M_{15}& M_{16}\\ M_{21}& M_{22}& M_{23}& M_{24}& M_{25}& M_{26}\end{array}\right]\·\left[\begin{array}{c}MV1\\ MV2\\ MV3\\ MV4\\ MV5\\ MV6\end{array}\right]$

MV1_min≤MV1≤MV1_max

MV2_min≤MV2≤MV2_max

MV3_min≤MV3≤MV3_max

MV4_min≤MV4≤MV4_max

MV5_min≤MV5≤MV5_max

MV6_min≤MV6≤MV6_max

CV1 (0)=B1

CV2 (0)=B2

Wherein P represents control time domain, for natural number；J represents multivariate weighted target value；I is the integer between 1 to P；W_cv1, W_cv2, W_I1, W_I6Being weight coefficient, B1, B2 is the initial value of the output of process。

$\left[\begin{array}{c}CV1\\ CV2\end{array}\right]=\left[\begin{array}{cccccc}{M}_{11}& M_{12}& M_{13}& M_{14}& M_{15}& M_{16}\\ M_{21}& M_{22}& M_{23}& M_{24}& M_{25}& M_{26}\end{array}\right]\·\left[\begin{array}{c}MV1\\ MV2\\ MV3\\ MV4\\ MV5\\ MV6\end{array}\right]$ Represent the kinetic model between desulphurization denitration process input and output, this model can adopt parametric form (transmission function, difference equation etc.) or nonparametric form (step response, impulse response etc.) or model of mind (neutral net, fuzzy model etc.), and the purpose of model is in that to realize the prediction of process output in future。

Need the control sequence solved for (wherein P is for controlling time domain):

MV1=[MV1 (1) ... MV1 (P)],

MV2=[MV2 (1) ... MV2 (P)],

…

MV6=[MV6 (1) ... MV6 (P)],

In sampling instant, for described PREDICTIVE CONTROL problem, utilize nonlinear optimization method to calculate optimum control sequence, obtain:

MV1(1)^*MV1(2)^*…MV1(P)^*

MV2(1)^*MV2(2)^*…MV2(P)^*

MV6(1)^*MV6(2)^*…MV6(P)^*

By first controlling increment sequence, i.e. MV1 (1)^*, MV2 (1)^*, MV3 (1)^*, MV4 (1)^*, MV5 (1)^*With MV6 (1)^*Export the setting value as each base control loop。Repeat above-mentioned optimization and calculate process, it is achieved desulphurization denitration process Multi-variables optimum design controls。

Particular embodiments described above; the purpose of this utility model, technical scheme and beneficial effect have been further described; it it should be understood that; the foregoing is only specific embodiment of the utility model; it is not limited to this utility model; all within spirit of the present utility model and principle, any amendment of making, equivalent replacement, improvement etc., should be included within protection domain of the present utility model。

Claims (5)

1. the flue gas desulfurization and denitrification integration apparatus of a multivariable Control, described flue gas desulfurization and denitrification integration apparatus includes booster fan, desulfurizing tower, denitrating tower, and Detection of Process Parameters device, procedure parameter regulate device and computer control system, it is characterised in that:

Described Detection of Process Parameters device contains desulfurizing tower inlet flue gas component detection apparatus and denitrating tower exiting flue gas component detection apparatus, and containing more than one devices in booster fan outlet pressure detecting device, desulfurizing tower entrance flow of ozone amount detecting device, denitrating tower entrance flow of ozone amount detecting device；

Described procedure parameter regulates that device comprises that booster fan outlet pressure regulates device, desulfurizing tower entrance flow of ozone quantity regulating device, denitrating tower entrance flow of ozone quantity regulating device, doctor solution circular flow regulate device, denitration liquid circular flow regulates device and denitrating tower column bottoms pump and delivers to the two or more devices in the denitration liquid flow regulator of desulfurizing tower tower top；

Described computer control system connects described each Detection of Process Parameters device and procedure parameter regulates device, receive the process parameter signals of described each Detection of Process Parameters device output, run desulphurization denitration process multivariable Control algorithm and regulate device output control signal to each described procedure parameter。

2. the flue gas desulfurization and denitrification integration apparatus of multivariable Control according to claim 1, it is characterized in that, described Detection of Process Parameters device farther includes disturbance feedforward detecting device, and described disturbance feedforward detecting device includes desulfurizing tower reservoir pH value measurement apparatus and/or denitration liquid urea content detecting device。

3. the flue gas desulfurization and denitrification integration apparatus of multivariable Control according to claim 1 and 2, it is characterised in that described flue gas desulfurization and denitrification integration apparatus is wet-type ammonia forced turbulent desulfurization, forces oxidation carbamide denitrification integral equipment。

4. the flue gas desulfurization and denitrification integration apparatus of multivariable Control according to claim 3, it is characterized in that, described Detection of Process Parameters device farther includes at least one device in liquid level detection device, ammonium sulfate circulating slot liquid level detection device, desulfurizing tower reservoir gravity detecting device, ammonium sulfate circulating slot at the bottom of desulfurizing tower reservoir oxidation air entrance wind pressure detection device, denitration tower bottoms amount detecting device, desulfurizing tower reservoir liquid level detection device, denitrating tower tower in liquid specific gravity detecting device and doctor solution pH value detecting device。

5. the flue gas desulfurization and denitrification integration apparatus of multivariable Control according to claim 3, it is characterised in that described procedure parameter adjustment device farther includes ammonium sulfate and follows ammonium concentration cycles pump adjustment device and/or ammonia aqua stream quantity regulating device。