CN103605877A - Method for renewal screening of catalyst of selective catalytic reduction (SCR) denitration system and system thereof - Google Patents

Abstract

The invention provides a method for renewal screening of a catalyst of a selective catalytic reduction (SCR) denitration system and a system thereof. The method comprises the steps of calculating the inactivation speed of the catalyst of the SCR denitration system; performing activity prediction on the catalyst in the SCR denitration system according to the inactivation speed of the catalyst; calculating potentiality of the SCR denitration system and the service life of the catalyst according to activity prediction results; obtaining renewal costs of the catalyst under every catalyst renewal scheme according to the service life of the catalyst; selecting a catalyst renewal scheme according to the renewal costs of the catalyst; and renewing the catalyst of the SCR denitration system according to the renewal scheme. According to the method, accurate time for catalyst renewal can be determined, and the SCR denitration system can run normally.

Description

Catalyst updating screening technique and the system thereof of SCR denitrating system

Technical field

The present invention relates to the technical field of SCR denitrating system, particularly relate to a kind of catalyst updating screening technique of SCR denitrating system, and a kind of catalyst updating screening system of SCR denitrating system.

Background technology

The principle of SCR (Selective Catalytic Reduction, selective catalytic reduction) is under catalyst action, reductive agent NH ₃at 290-400 ℃ by NO and NO ₂be reduced into N ₂, and there is hardly NH ₃oxidation reaction, thereby improved N ₂selectivity, reduced NH ₃consumption.

Along with the widespread use of SCR denitrating system in power plants, the operational management problem of SCR catalyzer and denitrating system becomes increasingly conspicuous.SCR denitrating system catalyst activity be an important indicator of SCR denitrating system operation, be related to the operation conditions of SCR denitrating system.Therefore upgrading in time of catalyzer is a major issue of SCR denitrating system, is not only related to the normal operation of SCR denitrating system, is also related to the control of cost.

The catalyst updating method of conventional SCR denitrating system is that the catalyzer of SCR denitrating system is sampled, catalyst samples tested, and the activity of estimation catalyzer, thus according to the activity of catalyst samples, determine whether to carry out catalyst updating.

Yet such update method needs constantly catalyzer to be carried out to sampling and testing, and in actual operation process, only can sample catalyzer when shutting down maintenance.When therefore said method can only be shut down maintenance, can whether upgrade according to the sample activity judgment of catalyzer sampling; and cannot determine the correct time of catalyst updating; if catalyzer activity decreased between twice sample time needs to upgrade; according to said method, cannot process, in may causing during this period of time, the operation of SCR denitrating system is undesired.

Summary of the invention

For the catalyst updating method of the SCR denitrating system existing in above-mentioned background technology, cannot determine the problem of the correct time of catalyst updating, the object of the present invention is to provide a kind of catalyst updating screening technique of SCR denitrating system of the correct time that can determine catalyst updating.

A catalyst updating screening technique for SCR denitrating system, comprises the following steps:

Calculate the deactivation rate of the catalyzer of described SCR denitrating system;

According to the deactivation rate of described catalyzer, the catalyzer in described SCR denitrating system is carried out to Activity Prediction;

According to Activity Prediction result, calculate the life-span of potential and the catalyzer of described SCR denitrating system;

According to the life-span of described catalyzer, obtain the renewal cost of catalyzer under each catalyst updating scheme;

According to the renewal cost of described catalyzer, select described catalyst updating scheme;

According to described update scheme, the catalyzer of described SCR denitrating system is upgraded.

First the catalyst updating screening technique of SCR denitrating system of the present invention detects the deactivation rate of catalyzer.According to the deactivation rate of described catalyzer, the catalyzer in described SCR denitrating system is carried out to Activity Prediction; Then according to Activity Prediction result, calculate the life-span of potential and the catalyzer of described SCR denitrating system; Obtain the renewal cost of catalyzer under each catalyst updating scheme, select suitable catalyst updating scheme to carry out catalyst updating.Only need to be according to the deactivation rate prediction potential of reactor and the life-span of catalyzer of catalyzer, just can accurately determine the catalyst updating time before the performance deficiency of reactor, thereby determine suitable catalyst updating scheme, so that operation and the catalyst updating of rational management SCR denitrating system.

The present invention also aims to provide the catalyst updating screening system of the SCR denitrating system that the catalyst updating screening technique of a kind of and above-mentioned SCR denitrating system is corresponding.

A catalyst updating screening system for SCR denitrating system, comprising:

Inactivation computing module, for calculating the deactivation rate of the catalyzer of described SCR denitrating system;

Activity Prediction module, for according to the deactivation rate of described catalyzer, carries out Activity Prediction to the catalyzer in described SCR denitrating system;

Potential computing module, for according to Activity Prediction result, calculates the life-span of potential and the catalyzer of described SCR denitrating system;

Cost acquisition module, for obtaining the renewal cost of catalyzer under each catalyst updating scheme according to the life-span of described catalyzer;

Select module, for according to the renewal cost of described catalyzer, select described catalyst updating scheme;

Update module, for upgrading the catalyzer of described SCR denitrating system according to described update scheme.

In the catalyst updating screening system of SCR denitrating system of the present invention, described inactivation computing module detects the deactivation rate of catalyzer.Described Activity Prediction module, according to the deactivation rate of described catalyzer, is carried out Activity Prediction to the catalyzer in described SCR denitrating system; Described potential computing module, according to Activity Prediction result, calculates the life-span of potential and the catalyzer of described SCR denitrating system; Described cost acquisition module obtains the renewal cost of catalyzer under each catalyst updating scheme, and described selection module selects suitable catalyst updating scheme so that described update module is carried out catalyst updating.Only need to be according to the deactivation rate prediction potential of reactor and the life-span of catalyzer of catalyzer, just can accurately determine the catalyst updating time before the performance deficiency of reactor, thereby determine suitable catalyst updating scheme, so that operation and the catalyst updating of rational management SCR denitrating system.

Accompanying drawing explanation

Fig. 1 is the schematic flow sheet of the catalyst updating screening technique of SCR denitrating system of the present invention;

Fig. 2 is the catalyst arrangement schematic diagram of SCR Benitration reactor;

Fig. 3 to Fig. 5 is respectively SCR potential in three kinds of catalyst updating schemes, the escaping of ammonia change curve schematic diagram along with working time;

The structural representation of the catalyst updating screening system of Fig. 6 SCR denitrating system of the present invention.

Embodiment

Refer to Fig. 1, Fig. 1 is the schematic flow sheet of the catalyst updating screening technique of SCR denitrating system of the present invention.

The catalyst updating screening technique of described SCR denitrating system, comprises the following steps:

S101, calculates the deactivation rate of the catalyzer of described SCR denitrating system;

S102, according to the deactivation rate of described catalyzer, carries out Activity Prediction to the catalyzer in described SCR denitrating system;

S103, according to Activity Prediction result, calculates the life-span of potential and the catalyzer of described SCR denitrating system;

S104, obtains the renewal cost of catalyzer under each catalyst updating scheme according to the life-span of described catalyzer;

S105, according to the renewal cost of described catalyzer, selects described catalyst updating scheme;

S106, upgrades the catalyzer of described SCR denitrating system according to described update scheme.

First the catalyst updating screening technique of SCR denitrating system of the present invention detects the deactivation rate of catalyzer.According to the deactivation rate of described catalyzer, the catalyzer in described SCR denitrating system is carried out to Activity Prediction; Then according to Activity Prediction result, calculate the life-span of potential and the catalyzer of described SCR denitrating system; Obtain the renewal cost of catalyzer under each catalyst updating scheme, select suitable catalyst updating scheme to carry out catalyst updating.Only need to be according to the deactivation rate prediction potential of reactor and the life-span of catalyzer of catalyzer, just can accurately determine the catalyst updating time before the performance deficiency of reactor, thereby determine suitable catalyst updating scheme, so that operation and the catalyst updating of rational management SCR denitrating system.

For above-mentioned steps S101, can, to obtaining the activity of described catalyzer by detection with the rule of accumulation variation duration of contact of catalyzer and reactant, calculate the deactivation rate that obtains described catalyzer.For example can regularly to catalyzer, sample, and sample be carried out to activity and calculate, then according to sample time and the active time dependent rule of activity of determining catalyzer of sample.Comprise the following steps:

Catalyzer to every layer in the process of using at catalyzer regularly samples;

Under simulated flue gas condition, measure the activity of catalyst samples, then according to the data of measuring, solve the inactivation equation of catalyzer:

r _k＝-d _k/d _tc

In formula, r _kdeactivation rate for catalyzer; t _cfor the accumulative total duration of contact of catalyzer and reactant, k is catalyst activity.

When the catalyzer of SCR denitrating system is sampled, preferably when compressor emergency shutdown scheduled outage, carry out catalyzer sampling, then outside system, catalyst samples is carried out to activity and detect, obtain the activity of catalyzer.

When calculate obtaining catalyst activity, can to described catalyzer sample, carry out activity detection by various common activity test methods in the industry.In one embodiment, described catalyzer sample is carried out to activity and detect, the step that obtains catalyst activity comprises:

Obtain the simulated flue gas flow using when described catalyzer sample is carried out to active detection, and catalyzer schedule of samples area, by described simulated flue gas flow and the following formula of catalyzer schedule of samples area substitution, the face velocity that calculated activity detects:

${\mathrm{AV}}_{\mathrm{test}}=\left(\frac{{\stackrel{\·}{V}}_{\mathrm{test}}}{A_{\mathrm{test}}}\right),$

Wherein, AV _testfor the face velocity of activity detection,

for simulated flue gas flow, A _testfor catalyzer sample piece surface area;

Obtain the import NH of testing apparatus when described catalyzer sample is carried out to active detection ₃concentration and outlet NH ₃concentration, by described import NH ₃concentration and outlet NH ₃the following formula of concentration substitution, calculates NO _xremoval efficiency:

${\mathrm{\η}}_{\mathrm{NOx}}=\left(\frac{{\mathrm{NH}}_{3,\mathrm{inlet}}-{\mathrm{NH}}_{3,\mathrm{outlet}}}{{\mathrm{NH}}_{3,\mathrm{inlet}}}\right),$

Wherein, η _nOxfor NO _xremoval efficiency, NH _{3, inlet}for import NH ₃concentration, NH _{3, outlet}for outlet NH ₃concentration;

Face velocity and NO that the activity that above-mentioned calculating is obtained detects _xthe following formula of removal efficiency substitution, calculates described catalyst activity:

K _test＝-AV _test·ln(1-η _NOx)，

Wherein, K _testfor catalyst activity, AV _testfor the face velocity that activity detects, η _nOxfor NO _xremoval efficiency.

For above-mentioned steps S102, according to the deactivation rate of described catalyzer, the step of the catalyzer in described SCR denitrating system being carried out to Activity Prediction comprises:

According to following formula, calculate the activity of described catalyzer:

k＝k ₀exp(-At)

In formula, k is catalyst activity, k ₀for the initial activity of catalyzer, A is deactivation rate, and t is the accumulative total duration of contact of catalyzer and reactant.

The single SCR Benitration reactor of thermal power plant is generally provided with 2～3 layers of catalyzer, and the deactivation rate of the catalyzer of different layers is different.As a rule the 1st layer owing to approaching most reactor inlet, and flue gas condition is more severe, and its deactivation rate will be higher than 2 layers of catalyzer below.There is linear ratio relation in the deactivation rate of supposing 3 layers of catalyzer herein, and the 3rd layer of the 2nd layer of > of the 1st layer of >.

For above-mentioned steps S103, reactor is the core component of SCR denitrating system, is NO in flue gas _xwith NH ₃on catalyst surface, reaction generates N ₂and H ₂the place of O.SCR Benitration reactor has two most important performance index: denitration efficiency and the escaping of ammonia rate (outlet ammonia concentration).Power plant formulates catalyzer management plan according to these two performance index, determines when to install additional catalyzer or catalyst changeout more.By the activity of the measurable catalyzer of above-mentioned steps, from active angle, SCR Benitration reactor is carried out to performance calculating, and calculate denitration efficiency and the escaping of ammonia rate, for judging whether catalyzer upgrades, do basis.

The catalyzer of SCR Benitration reactor has adopted the arrangement form of " 2+1 " mostly.2 layers of catalyzer are installed while moving while just starting, are made preparation layers for reserved the 3rd layer, by the time moved when a period of time, rear catalyst performance can not meet service requirement and install additional, catalyst arrangement as shown in Figure 2.

Flue gas flows to from Reactor inlet, passes through successively from top to bottom each layer of catalyzer, and denitration reaction occurs, and finally from reactor outlet, flows out.While carrying out the calculating of SCR Benitration reactor performance, adopt the successively method of calculated, and do following some simplification processing:

(1) the outlet Gas Parameters of last layer catalyzer is as the inlet flue gas parameter of lower one deck catalyzer;

(2) Reactor inlet Gas Parameters is as the import Gas Parameters of ground floor catalyzer;

(3) the outlet Gas Parameters of last one deck catalyzer is as the outlet Gas Parameters of whole reactor;

Obtain reactor known conditions as after import Gas Parameters, catalyzer parameter, from ground floor catalyzer, start to calculate.

Calculating the potential of described SCR denitrating system and the life-span of catalyzer comprises:

Obtain each layer of catalyst inlet ammonia nitrogen ratio, each layer of catalyst inlet flue gas flow, and each layer of catalyst surface area, obtain the denitration efficiency of each layer of catalyzer according to following formula:

${\mathrm{\&eta;}}_i=\left\{\begin{array}{c}1-e^{-\frac{K_i}{{\mathrm{AV}}_i}},{\mathrm{\&gamma;}}_i\&GreaterEqual;1.0\\ {\mathrm{\&gamma;}}_i(1-e^{-\frac{K_i}{{\mathrm{AV}}_i}}),{\mathrm{\&gamma;}}_i<1.0\end{array}\right.$

Wherein, η i is the denitration efficiency of i layer catalyzer, and γ i is i layer catalyst inlet ammonia nitrogen ratio, and Ki is i layer catalyst activity, and AVi is the face velocity of i layer catalyzer, and, vi is i layer catalyst inlet flue gas flow, and Ai is i layer catalyst surface area;

According to following formula, obtain NOx concentration and the escaping of ammonia rate of SCR denitrating system reactor outlet:

$C_{\mathrm{NOx},\mathrm{out}}=C_{\mathrm{NOx},\mathrm{in}}\underset{i=1}{\overset{n}{\mathrm{\&Pi;}}}(1-{\mathrm{\&eta;}}_i)$

$C_{\mathrm{NH}3,\mathrm{out}}={\mathrm{\&gamma;C}}_{\mathrm{NOx},\mathrm{in}}\underset{i=1}{\overset{n}{\mathrm{\&Pi;}}}(1-{\mathrm{\&eta;}}_i)$

Wherein, CNOx, in is NOx inlet concentration, CNOx, out is NOx exit concentration, γ is Reactor inlet ammonia nitrogen ratio;

According to following formula, obtain the potential of catalyzer:

${\mathrm{RP}}_i=\frac{K_i}{{\mathrm{AV}}_i}$

Wherein, RPi is the potential of i layer catalyzer, and Ki is i layer catalyst activity, and AVi is the face velocity of i layer catalyzer;

According to NOx concentration and the escaping of ammonia rate of the potential of described catalyzer and described SCR denitrating system reactor outlet, judgement catalyst life.

For above-mentioned steps S104, according to the life-span of described catalyzer, obtain the renewal cost of catalyzer under each catalyst updating scheme;

Because relate to catalyst updating, so be mainly the renewal cost of considering catalyzer itself, in one embodiment directly according to the life-span of catalyzer under various catalyst updating schemes, obtain the cost of catalyst changeout more as the renewal cost of catalyzer under each catalyst updating scheme.

Therefore, respectively according to update time, the renewal frequency of catalyzer under various catalyst updating schemes, update mode, the cost producing while at every turn upgrading under various substitute modes etc. calculates the renewal cost of catalyzer under each catalyst updating scheme.

And as another kind of preferred implementation, the performance of catalyzer directly affects the operation conditions of reactor, when estimation catalyst change cost, can further add denitrating system day-to-day operation cost and environmental protection cost etc.The prime cost of denitrating system day-to-day operation not only comprises liquefied ammonia, also needs to consider power consumption etc., and for adopting liquefied ammonia to do the SCR denitrating system of reductive agent, the induced draft fan power consumption that its SR increase causes is main.

In this preferred implementation, in certain hour t, the cost of catalyst updating is F(t), so,

F(t)＝C(t)+P(t)+E(t)+…

Wherein, C (t) is that catalyzer relevant cost, P (t) are that denitrating system day-to-day operation cost, E (t) are environmental protection cost.

At t, in the time, the average cost hourly of catalyst updating is:

f＝F(t)/t

By catalyst deactivation function, predict the potential of SCR denitrating system and the life-span of catalyzer of various update scheme; use reactor performance computing formula to calculate the denitration performance desired value of various update scheme; comprise outlet NOx content and the escaping of ammonia; under the condition of security of guaranteeing SCR operation, in conjunction with power plant, shut down the update time of the various update scheme of plan; thereby estimate every cost of catalyst updating; but because on-the-spot SCR operation conditions is very complicated; relative expense is various, pretends following simplification and hypothesis:

1, SCR operating condition is custom operating mode;

2, SCR system entry NOx remains unchanged;

3, the initial activity of regenerated catalyst is active consistent with fresh catalyst, but the deactivation rate of regeneration rear catalyst accelerates 20%;

4, catalyst updating cost is mainly considered catalyzer relevant cost, denitrating system day-to-day operation cost and environmental protection cost.Wherein catalyzer relevant cost comprises again expense, the regenerated catalyst expense of raw catelyst of buying, the expense that catalyst costs, the discarded catalyzer of disposal are installed; Denitrating system day-to-day operation cost comprises the power consumption that liquefied ammonia expense, induced draft fan increase; Environmental protection cost is that NO reduces discharging cost.

Therefore,, in certain hour t, the cost of catalyst updating is:

F(t)＝C(t)+P(t)+E(t)，

In formula,

C(t)＝C ₁(t)+C ₂(t)+C ₃(t)+C ₄(t)，

P(t)＝P ₁(t)+P ₂(t)，

E(t)＝E ₁(t)；

Wherein, C ₁(t) for buying expense, the C of raw catelyst ₂(t) be regenerated catalyst expense, C ₃(t) catalyst costs, C are installed ₄(t) dispose the expense of discarded catalyzer; P ₁(t) be liquefied ammonia expense, P ₂(t) power consumption increasing for induced draft fan; E ₁(t) for NO reduces discharging cost.

S105, according to the renewal cost of described catalyzer, selects described catalyst updating scheme;

In this step, the common lower-cost catalyst updating scheme of renewal of selecting catalyst, has reached the object of the operation cost that reduces described SCR denitrating system.

S106, upgrades the catalyzer of described SCR denitrating system according to described update scheme.

In this step, catalyst updating time, the renewal frequency according to the update scheme of selecting, set, update mode, upgrades the catalyzer of described SCR denitrating system.Catalyst updating mode comprises changes brand-new catalyzer, or upgrades wherein a kind of or two kinds of combinations of these two kinds of modes of regenerated catalyst.

Of the present invention with a specific embodiment explanation below

Utilize reactor performance computing formula and catalyst deactivation function can obtain SCR potential, the escaping of ammonia change curve along with working time; the NO emission limit of combined catalyst bimetry and activity, pollutant emission laws and regulations regulation and power plant have shut down plan three kinds of schemes catalyst updating time in 100000h; as show as shown in following table, SCR potential, the escaping of ammonia along with the change curve of whole service time as in Figure 3-5.

Each scheme catalyst change time

Fig. 3-5th, the escaping of ammonia and potential are with the change curve of working time, and upper part is reactor potential curve over time, and potential warning line is 4.31, and, in SCR operational process, minimum potential can not be lower than 4.31; Lower part is the escaping of ammonia temporal evolution curve, and the escaping of ammonia warning line is 3ppm, and in SCR operational process, the highest the escaping of ammonia can not surpass 3ppm.In working time 64, in 800h, the update scheme of three kinds of schemes is all consistent, is all first to move two-layer raw catelyst, then adds the 3rd layer of catalyzer.As can be seen from the figure SCR potential constantly reduces along with the passing of working time, this is because the activity of every layer of catalyzer reduces because of obstruction, sintering, the factor passing in time such as poisoning, thereby cause the potential of every layer of catalyzer to reduce, the whole potential of SCR reduces; The escaping of ammonia constantly increases along with the passing of working time, and this is because active decline declines denitration ability, needs to drop into more ammonia and is no more than 100mg/Nm3 to guarantee SCR outlet NO concentration.

Shown in Fig. 3-4, the expected life of the two-layer catalyzer that puts into operation can reach 22,984h, but need to add the 3rd layer when 21, the 600h because of the plan of shutting down; While adding the 3rd layer, SCR potential is 7.6726, and the two-layer potential that newly puts into operation has improved 17.69%, and be 43,200h its working time, before adding, has increased by one times, but flue gas resistance also can improve 200Pa left and right, and the power consumption of induced draft fan also will increase; Traditional scheme is moving 64; after 800h because of the ground floor catalyzer of having shut down programmed replacement; after changing, SCR catalyzer expected life can reach 32; 259h; but because shutdown plan must be changed the second layer in advance; make to change the whole potential of front SCR and still have 5.0175, changing SCR potential after the second layer is 7.3131, while changing ground floor large 5.1%.

As shown in Fig. 4 and following table, the update time of prioritization scheme 1 is the same with the update time of traditional scheme, but in 100,000h, the catalyst life after traditional scheme is changed is for the first time 32,259h, and prioritization scheme 1 for the first time regeneration after catalyst life be 28,946h, prioritization scheme 1 has reduced 3 compared with traditional scheme, 313h, the life-span has shortened 10.27%.

As shown in Fig. 5 and following table, it is 6.9758 that prioritization scheme 2 is changed rear potential for the first time, compared with traditional scheme and prioritization scheme 1, has increased by 0.0207, illustrates that reasonably transposing catalyzer can make the whole potential of catalyzer increase; The time of operation is 32,400h, and compared with 21 of traditional scheme, 600h has increased by 50% working time, and its life-span is 40,856h, and compared with the life-span of traditional scheme 32,259h has increased by 21.04%.

Potential and working time when each scheme is upgraded

Cost benefit judgement to various schemes:

Three kinds of schemes are for the third time (64,800h), before upgrading, its all costs are all the same, for the cost of three kinds of schemes of assessment and analysis, to each scheme for the third time the cost of reproducting periods estimate, calculate the cost of update scheme per hour during this.

According to the catalyst updating result of three kinds of schemes, do not consider other factors such as equipment amortization, interest rate, can estimate the every cost that upgrades for the third time run duration, as shown in the table.For the third time, upgrade run duration, the renewal cost minimization per hour of prioritization scheme 1 expection, is 1,912.23 yuan; Prioritization scheme 2 takes second place, and is 1,998.89 yuan; Traditional scheme is maximum, is 2,227.89 yuan; Prioritization scheme 1 is expected 315.66 yuan of saving per hour compared with the traditional scheme of update scheme, compared with 86.66 yuan of prioritization scheme 2 expection saving per hour.The main cause that prioritization scheme 1 cost is low is that catalyzer relevant cost is minimum, wherein the cost of regenerated catalyst be raw catelyst cost 60%, so the economy advantage of catalyst regeneration scheme in catalyst updating scheme is the most obvious.And the prioritization scheme 2 costs reason low compared with traditional scheme is to have extended the bulk life time of SCR system by rational transposing catalyzer, after upgrading for the third time, traditional scheme and 1 working time of prioritization scheme are 21,600h, and be 32 the working time of prioritization scheme 2,400h, thus make prioritization scheme 2 renewal cost hourly lower than traditional scheme.

Each scheme prime cost

Refer to Fig. 6, the structural representation of the catalyst updating screening system of Fig. 6 SCR denitrating system of the present invention.

The catalyst updating screening system of described SCR denitrating system, comprising:

Inactivation computing module 11, for calculating the deactivation rate of the catalyzer of described SCR denitrating system;

Activity Prediction module 12, for according to the deactivation rate of described catalyzer, carries out Activity Prediction to the catalyzer in described SCR denitrating system;

Potential computing module 13, for according to Activity Prediction result, calculates the life-span of potential and the catalyzer of described SCR denitrating system;

Cost acquisition module 14, for obtaining the renewal cost of catalyzer under each catalyst updating scheme according to the life-span of described catalyzer;

Select module 15, for according to the renewal cost of described catalyzer, select described catalyst updating scheme;

Update module 16, for upgrading the catalyzer of described SCR denitrating system according to described update scheme.

The catalyst updating screening system of SCR denitrating system of the present invention detects the deactivation rate of catalyzer.According to the deactivation rate of described catalyzer, the catalyzer in described SCR denitrating system is carried out to Activity Prediction; Then according to Activity Prediction result, calculate the life-span of potential and the catalyzer of described SCR denitrating system; Obtain the renewal cost of catalyzer under each catalyst updating scheme, select suitable catalyst updating scheme to carry out catalyst updating.Only need to be according to the deactivation rate prediction potential of reactor and the life-span of catalyzer of catalyzer, just can accurately determine the catalyst updating time before the performance deficiency of reactor, thereby determine suitable catalyst updating scheme, so that operation and the catalyst updating of rational management SCR denitrating system.

Described inactivation computing module 11 can, to obtaining the activity of described catalyzer by detection with the rule of accumulation variation duration of contact of catalyzer and reactant, calculate the deactivation rate that obtains described catalyzer.For example can regularly to catalyzer, sample, and sample be carried out to activity and calculate, then according to sample time and the active time dependent rule of activity of determining catalyzer of sample.

Particularly, the catalyzer to every layer in the process that described inactivation computing module 11 is used at catalyzer regularly samples, and under simulated flue gas condition, measures the activity of catalyst samples, then according to the data of measuring, solves the inactivation equation of catalyzer:

r _k＝-d _k/d _tc

In formula, r _kdeactivation rate for catalyzer; t _cfor the accumulative total duration of contact of catalyzer and reactant, k is catalyst activity.

When the catalyzer of 11 pairs of SCR denitrating systems of described inactivation computing module samples, preferably when compressor emergency shutdown scheduled outage, carry out catalyzer sampling, then outside system, catalyst samples is carried out to activity and detect, obtain the activity of catalyzer.

Described inactivation computing module 11, when calculate obtaining catalyst activity, can carry out activity detection to described catalyzer sample by various common activity test methods in the industry.

In one embodiment, described inactivation computing module 11 obtains the simulated flue gas flow using when described catalyzer sample is carried out to active detection, and catalyzer schedule of samples area, by described simulated flue gas flow and the following formula of catalyzer schedule of samples area substitution, the face velocity that calculated activity detects:

${\mathrm{AV}}_{\mathrm{test}}=\left(\frac{{\stackrel{\&CenterDot;}{V}}_{\mathrm{test}}}{A_{\mathrm{test}}}\right),$

Wherein, AV _testfor the face velocity of activity detection,

for simulated flue gas flow, A _testfor catalyzer sample piece surface area;

Obtain the import NH of testing apparatus when described catalyzer sample is carried out to active detection ₃concentration and outlet NH ₃concentration, by described import NH ₃concentration and outlet NH ₃the following formula of concentration substitution, calculates NO _xremoval efficiency:

${\mathrm{\&eta;}}_{\mathrm{NOx}}=\left(\frac{{\mathrm{NH}}_{3,\mathrm{inlet}}-{\mathrm{NH}}_{3,\mathrm{outlet}}}{{\mathrm{NH}}_{3,\mathrm{inlet}}}\right),$

Wherein, η _nOxfor NO _xremoval efficiency, NH _{3, inlet}for import NH ₃concentration, NH _{3, outlet}for outlet NH ₃concentration;

Face velocity and NO that the activity that above-mentioned calculating is obtained detects _xthe following formula of removal efficiency substitution, calculates described catalyst activity:

K _test＝-AV _test·ln(1-η _NOx)，

Wherein, K _testfor catalyst activity, AV _testfor the face velocity that activity detects, η _nOxfor NO _xremoval efficiency.

Described Activity Prediction module 12 is calculated the activity of described catalyzer according to following formula:

k＝k ₀exp(-At)

In formula, k is catalyst activity, k ₀for the initial activity of catalyzer, A is deactivation rate, and t is the accumulative total duration of contact of catalyzer and reactant.

The single SCR Benitration reactor of thermal power plant is generally provided with 2～3 layers of catalyzer, and the deactivation rate of the catalyzer of different layers is different.As a rule the 1st layer owing to approaching most reactor inlet, and flue gas condition is more severe, and its deactivation rate will be higher than 2 layers of catalyzer below.There is linear ratio relation in the deactivation rate of supposing 3 layers of catalyzer herein, and the 3rd layer of the 2nd layer of > of the 1st layer of >.

Described potential computing module 13, for according to Activity Prediction result, calculates the life-span of potential and the catalyzer of described SCR denitrating system;

Reactor is the core component of SCR denitrating system, is NO in flue gas _xwith NH ₃on catalyst surface, reaction generates N ₂and H ₂the place of O.SCR Benitration reactor has two most important performance index: denitration efficiency and the escaping of ammonia rate (outlet ammonia concentration).Power plant formulates catalyzer management plan according to these two performance index, determines when to install additional catalyzer or catalyst changeout more.By the activity of the measurable catalyzer of above-mentioned steps, from active angle, SCR Benitration reactor is carried out to performance calculating, and calculate denitration efficiency and the escaping of ammonia rate, for judging whether catalyzer upgrades, do basis.

The catalyzer of SCR Benitration reactor has adopted the arrangement form of " 2+1 " mostly.2 layers of catalyzer are installed while moving while just starting, are made preparation layers, by the time moved when a period of time, rear catalyst performance can not meet service requirement and install additional again for reserved the 3rd layer.

Flue gas flows to from Reactor inlet, passes through successively from top to bottom each layer of catalyzer, and denitration reaction occurs, and finally from reactor outlet, flows out.While carrying out the calculating of SCR Benitration reactor performance, adopt the successively method of calculated, and do following some simplification processing:

(1) the outlet Gas Parameters of last layer catalyzer is as the inlet flue gas parameter of lower one deck catalyzer;

(2) Reactor inlet Gas Parameters is as the import Gas Parameters of ground floor catalyzer;

(3) the outlet Gas Parameters of last one deck catalyzer is as the outlet Gas Parameters of whole reactor;

Obtain reactor known conditions as after import Gas Parameters, catalyzer parameter, from ground floor catalyzer, start to calculate.

Described potential computing module 13 obtains each layer of catalyst inlet ammonia nitrogen ratio, and each layer of catalyst inlet flue gas flow, and each layer of catalyst surface area obtain the denitration efficiency of each layer of catalyzer according to following formula:

${\mathrm{\&eta;}}_i=\left\{\begin{array}{c}1-e^{-\frac{K_i}{{\mathrm{AV}}_i}},{\mathrm{\&gamma;}}_i\&GreaterEqual;1.0\\ {\mathrm{\&gamma;}}_i(1-e^{-\frac{K_i}{{\mathrm{AV}}_i}}),{\mathrm{\&gamma;}}_i<1.0\end{array}\right.$

Wherein, η i is the denitration efficiency of i layer catalyzer, and γ i is i layer catalyst inlet ammonia nitrogen ratio, and Ki is i layer catalyst activity, and AVi is the face velocity of i layer catalyzer, and,

vi is i layer catalyst inlet flue gas flow, and Ai is i layer catalyst surface area;

According to following formula, obtain NOx concentration and the escaping of ammonia rate of SCR denitrating system reactor outlet:

$C_{\mathrm{NOx},\mathrm{out}}=C_{\mathrm{NOx},\mathrm{in}}\underset{i=1}{\overset{n}{\mathrm{\&Pi;}}}(1-{\mathrm{\&eta;}}_i)$

$C_{\mathrm{NH}3,\mathrm{out}}={\mathrm{\&gamma;C}}_{\mathrm{NOx},\mathrm{in}}\underset{i=1}{\overset{n}{\mathrm{\&Pi;}}}(1-{\mathrm{\&eta;}}_i)$

Wherein, CNOx, in is NOx inlet concentration, CNOx, out is NOx exit concentration, γ is Reactor inlet ammonia nitrogen ratio;

According to following formula, obtain the potential of catalyzer:

${\mathrm{RP}}_i=\frac{K_i}{{\mathrm{AV}}_i}$

Wherein, RPi is the potential of i layer catalyzer, and Ki is i layer catalyst activity, and AVi is the face velocity of i layer catalyzer;

According to NOx concentration and the escaping of ammonia rate of the potential of described catalyzer and described SCR denitrating system reactor outlet, judgement catalyst life.

Described cost acquisition module 14 obtains the renewal cost of catalyzer under each catalyst updating scheme according to the life-span of described catalyzer;

Because relate to catalyst updating, so be mainly the renewal cost of considering catalyzer itself, in one embodiment directly according to the life-span of catalyzer under various catalyst updating schemes, obtain the cost of catalyst changeout more as the renewal cost of catalyzer under each catalyst updating scheme.

Therefore, respectively according to update time, the renewal frequency of catalyzer under various catalyst updating schemes, update mode, the cost producing while at every turn upgrading under various substitute modes etc. calculates the renewal cost of catalyzer under each catalyst updating scheme.

And as another kind of preferred implementation, the performance of catalyzer directly affects the operation conditions of reactor, when estimation catalyst change cost, can further add denitrating system day-to-day operation cost and environmental protection cost etc.The prime cost of denitrating system day-to-day operation not only comprises liquefied ammonia, also needs to consider power consumption etc., and for adopting liquefied ammonia to do the SCR denitrating system of reductive agent, the induced draft fan power consumption that its SR increase causes is main.

In this preferred implementation, in certain hour t, the cost of catalyst updating is F(t), so,

F(t)＝C(t)+P(t)+E(t)+…

Wherein, C (t) is that catalyzer relevant cost, P (t) are that denitrating system day-to-day operation cost, E (t) are environmental protection cost.

At t, in the time, the average cost hourly of catalyst updating is:

f＝F(t)/t

By catalyst deactivation function, predict the potential of SCR denitrating system and the life-span of catalyzer of various update scheme; use reactor performance computing formula to calculate the denitration performance desired value of various update scheme; comprise outlet NOx content and the escaping of ammonia; under the condition of security of guaranteeing SCR operation, in conjunction with power plant, shut down the update time of the various update scheme of plan; thereby estimate every cost of catalyst updating; but because on-the-spot SCR operation conditions is very complicated; relative expense is various, pretends following simplification and hypothesis:

1, SCR operating condition is custom operating mode;

2, SCR system entry NOx remains unchanged;

3, the initial activity of regenerated catalyst is active consistent with fresh catalyst, but the deactivation rate of regeneration rear catalyst accelerates 20%;

4, catalyst updating cost is mainly considered catalyzer relevant cost, denitrating system day-to-day operation cost and environmental protection cost.Wherein catalyzer relevant cost comprises again expense, the regenerated catalyst expense of raw catelyst of buying, the expense that catalyst costs, the discarded catalyzer of disposal are installed; Denitrating system day-to-day operation cost comprises the power consumption that liquefied ammonia expense, induced draft fan increase; Environmental protection cost is that NO reduces discharging cost.

Therefore,, in certain hour t, the cost of catalyst updating is:

F(t)＝C(t)+P(t)+E(t)，

In formula,

C(t)＝C ₁(t)+C ₂(t)+C ₃(t)+C ₄(t)，

P(t)＝P ₁(t)+P ₂(t)，

E(t)＝E ₁(t)；

Wherein, C ₁(t) for buying expense, the C of raw catelyst ₂(t) be regenerated catalyst expense, C ₃(t) catalyst costs, C are installed ₄(t) dispose the expense of discarded catalyzer; P ₁(t) be liquefied ammonia expense, P ₂(t) power consumption increasing for induced draft fan; E ₁(t) for NO reduces discharging cost.

Described selection module 15, according to the renewal cost of described catalyzer, is selected described catalyst updating scheme; Conventionally the lower-cost catalyst updating scheme of renewal of selecting catalyst, has reached the object of the operation cost that reduces described SCR denitrating system.

Described update module 16 is upgraded the catalyzer of described SCR denitrating system according to described update scheme.Catalyst updating time, the renewal frequency that can set according to the update scheme of selecting, update mode, upgrades the catalyzer of described SCR denitrating system.Catalyst updating mode comprises changes brand-new catalyzer, or upgrades wherein a kind of or two kinds of combinations of these two kinds of modes of regenerated catalyst.

One of ordinary skill in the art will appreciate that all or part of flow process and the corresponding system that realize in above-mentioned embodiment, to come the hardware that instruction is relevant to complete by computer program, described program can be stored in a computer read/write memory medium, this program, when carrying out, can comprise the flow process as the respective embodiments described above.Wherein, described storage medium can be magnetic disc, CD, read-only store-memory body (Read-Only Memory, ROM) or random store-memory body (Random Access Memory, RAM) etc.

The above embodiment has only expressed several embodiment of the present invention, and it describes comparatively concrete and detailed, but can not therefore be interpreted as the restriction to the scope of the claims of the present invention.It should be pointed out that for the person of ordinary skill of the art, without departing from the inventive concept of the premise, can also make some distortion and improvement, these all belong to protection scope of the present invention.Therefore, the protection domain of patent of the present invention should be as the criterion with claims.

Claims (10)

1. a catalyst updating screening technique for SCR denitrating system, is characterized in that, comprises the following steps:

Calculate the deactivation rate of the catalyzer of described SCR denitrating system;

According to the deactivation rate of described catalyzer, the catalyzer in described SCR denitrating system is carried out to Activity Prediction;

According to Activity Prediction result, calculate the life-span of potential and the catalyzer of described SCR denitrating system;

According to the life-span of described catalyzer, obtain the renewal cost of catalyzer under each catalyst updating scheme;

According to the renewal cost of described catalyzer, select described catalyst updating scheme;

According to described update scheme, the catalyzer of described SCR denitrating system is upgraded.

2. the catalyst updating screening technique of SCR denitrating system as claimed in claim 1, is characterized in that, the step of deactivation rate of calculating the catalyzer of described SCR denitrating system comprises:

Catalyzer to every layer regularly samples;

Under simulated flue gas condition, measure the activity of catalyst samples, then according to following formula, solve the deactivation rate of catalyzer:

r _k＝-d _k/d _tc

In formula, the deactivation rate that rk is catalyzer; Tc is the accumulative total duration of contact of catalyzer and reactant, and k is catalyst activity.

3. the catalyst updating screening technique of SCR denitrating system as claimed in claim 1, is characterized in that, according to the deactivation rate of described catalyzer, the step of the catalyzer in described SCR denitrating system being carried out to Activity Prediction comprises:

According to following formula, calculate the activity of described catalyzer:

k＝k ₀exp(-At)

In formula, k is catalyst activity, the initial activity that k0 is catalyzer, and A is deactivation rate, t is the accumulative total duration of contact of catalyzer and reactant.

4. the catalyst updating screening technique of SCR denitrating system as claimed in claim 1, is characterized in that, according to Activity Prediction result, calculates the potential of described SCR denitrating system and the step in the life-span of catalyzer comprises:

Obtain each layer of catalyst inlet ammonia nitrogen ratio, each layer of catalyst inlet flue gas flow, and each layer of catalyst surface area, obtain the denitration efficiency of each layer of catalyzer according to following formula:

Wherein, η i is the denitration efficiency of i layer catalyzer, and γ i is i layer catalyst inlet ammonia nitrogen ratio, and Ki is i layer catalyst activity, and AVi is the face velocity of i layer catalyzer, and,

vi is i layer catalyst inlet flue gas flow, and Ai is i layer catalyst surface area;

According to following formula, obtain NOx concentration and the escaping of ammonia rate of SCR denitrating system reactor outlet:

Wherein, CNOx, in is NOx inlet concentration, CNOx, out is NOx exit concentration, γ is Reactor inlet ammonia nitrogen ratio;

According to following formula, obtain the potential of catalyzer:

Wherein, RPi is the potential of i layer catalyzer, and Ki is i layer catalyst activity, and AVi is the face velocity of i layer catalyzer;

According to NOx concentration and the escaping of ammonia rate of the potential of described catalyzer and described SCR denitrating system reactor outlet, judgement catalyst life.

5. the catalyst updating screening technique of SCR denitrating system as claimed in claim 1, is characterized in that, according to the renewal cost of described catalyzer, selects the step of described catalyst updating scheme to comprise:

According to following formula, calculate the operating cost F(t of SCR denitrating system under described catalyst updating scheme):

F(t)＝C(t)+P(t)+E(t)

Wherein, C (t)=C ₁(t)+C ₂(t)+C ₃(t)+C ₄(t); P (t)=P ₁(t)+P ₂(t); E (t)=E ₁(t); C ₁(t) for buying expense, the C of raw catelyst ₂(t) be regenerated catalyst expense, C ₃(t) catalyst costs, C are installed ₄(t) dispose the expense of discarded catalyzer; P ₁(t) be liquefied ammonia expense, P ₂(t) power consumption increasing for induced draft fan; E ₁(t) for NO reduces discharging cost;

According to result of calculation, select the lower catalyst updating scheme of operating cost of SCR denitrating system.

6. a catalyst updating screening system for SCR denitrating system, is characterized in that, comprising:

Inactivation computing module, for calculating the deactivation rate of the catalyzer of described SCR denitrating system;

Activity Prediction module, for according to the deactivation rate of described catalyzer, carries out Activity Prediction to the catalyzer in described SCR denitrating system;

Potential computing module, for according to Activity Prediction result, calculates the life-span of potential and the catalyzer of described SCR denitrating system;

Cost acquisition module, for obtaining the renewal cost of catalyzer under each catalyst updating scheme according to the life-span of described catalyzer;

Select module, for according to the renewal cost of described catalyzer, select described catalyst updating scheme;

Update module, for upgrading the catalyzer of described SCR denitrating system according to described update scheme.

7. the catalyst updating screening system of SCR denitrating system as claimed in claim 6, it is characterized in that, described inactivation computing module regularly samples the catalyzer of every layer, and under simulated flue gas condition, measures the activity of catalyst samples, then according to following formula, solves the deactivation rate of catalyzer:

r _k＝-d _k/d _tc

In formula, the deactivation rate that rk is catalyzer; Tc is the accumulative total duration of contact of catalyzer and reactant, and k is catalyst activity.

8. the catalyst updating screening system of SCR denitrating system as claimed in claim 6, is characterized in that, described Activity Prediction module is calculated the activity of described catalyzer according to following formula:

k＝k ₀exp(-At)

In formula, k is catalyst activity, the initial activity that k0 is catalyzer, and A is deactivation rate, t is the accumulative total duration of contact of catalyzer and reactant.

9. the catalyst updating screening system of SCR denitrating system as claimed in claim 6, it is characterized in that, described potential computing module obtains each layer of catalyst inlet ammonia nitrogen ratio, each layer of catalyst inlet flue gas flow, and each layer of catalyst surface area, according to following formula, obtain the denitration efficiency of each layer of catalyzer:

Wherein, η i is the denitration efficiency of i layer catalyzer, and γ i is i layer catalyst inlet ammonia nitrogen ratio, and Ki is i layer catalyst activity, and AVi is the face velocity of i layer catalyzer, and,

vi is i layer catalyst inlet flue gas flow, and Ai is i layer catalyst surface area;

According to following formula, obtain NOx concentration and the escaping of ammonia rate of SCR denitrating system reactor outlet:

Wherein, CNOx, in is NOx inlet concentration, CNOx, out is NOx exit concentration, γ is Reactor inlet ammonia nitrogen ratio;

According to following formula, obtain the potential of catalyzer:

Wherein, RPi is the potential of i layer catalyzer, and Ki is i layer catalyst activity, and AVi is the face velocity of i layer catalyzer;

According to NOx concentration and the escaping of ammonia rate of the potential of described catalyzer and described SCR denitrating system reactor outlet, judgement catalyst life.

10. the catalyst updating screening system of SCR denitrating system as claimed in claim 6, is characterized in that, described selection module is calculated the operating cost F(t of SCR denitrating system under described catalyst updating scheme according to following formula):

F(t)＝C(t)+P(t)+E(t)

Wherein, C (t)=C ₁(t)+C ₂(t)+C ₃(t)+C ₄(t); P (t)=P ₁(t)+P ₂(t); E (t)=E ₁(t); C ₁(t) for buying expense, the C of raw catelyst ₂(t) be regenerated catalyst expense, C ₃(t) catalyst costs, C are installed ₄(t) dispose the expense of discarded catalyzer; P ₁(t) be liquefied ammonia expense, P ₂(t) power consumption increasing for induced draft fan; E ₁(t) for NO reduces discharging cost;

According to result of calculation, select the lower catalyst updating scheme of operating cost of SCR denitrating system.

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