CN104483450B - Tandem synthesis ammonia plant conversion section each change furnace entrance vapor-air ratio measures system - Google Patents

Abstract

The present invention relates to a kind of tandem synthesis ammonia plant conversion section each change furnace entrance vapor-air ratio and measure system, it intelligent secondary meter group unit including band communication function and gas composition analysis unit, it is provided with temperature-adjusting device between two adjacent change furnace sections, temperature control method is divided into interpolation steam, water spray cold shock and heat exchange；Sensor group cells in each change furnace section that mensuration system includes being installed on some series connection and pipeline, sensor group cells reacts gas temperature and the sensor combinations of pressure in main pipeline in main pipeline before including being arranged on change furnace section to be measured before measuring interpolation water vapour or cold shocking water, reacts in main pipeline gas temperature and the sensor combinations of pressure and be arranged in measuring interpolation water vapour or cold shocking water pipeline for measuring the sensor combinations of cold shocking water or steam temperature and pressure after measuring interpolation water vapour or cold shocking water.The present invention can static, online, the vapor-air ratio of the Automatic continuous each change furnace section of measurement.

Description

Tandem synthesis ammonia plant conversion section each change furnace entrance vapor-air ratio measures system

Technical field

The present invention relates to the measuring technology of a kind of synthesis ammonia plant, particularly to a kind of tandem synthesis ammonia plant conversion Workshop section's each change furnace entrance vapor-air ratio measures system.

Background technology

Synthesis ammonia plant carbon monoxide (CO) conversion section operation is a step crucial in Ammonia Production, and it is main Wanting task is that the CO in conversion gas is converted to CO₂And H₂.Owing to CO change procedure being strongly exothermic process, Segmentation must carry out being beneficial to reclaiming reaction heat, and control conversion section change furnace section middle outlet remnants CO and contain Amount.Additionally, for convenience of the temperature of control CO conversion section each change furnace section, simultaneously for convenience of to each conversion Stove section is added reactant feed.At present, conversion of carbon monoxide in synthetic ammonia plant workshop section is frequently with multi-segment structure, typically It is three sections or four segment structures.Water vapour is the CO main reactant of change workshop section and thermal medium, generally the The entrance of one section of change furnace section adds water vapour.Water spray cold shock is the intersegmental conventional temperature adjustment of change furnace and increases water The means of steam, it is common that Quench of spraying water between first paragraph and second segment change furnace section.Second segment and the 3rd Without water vapour or do not spray water between section or the 3rd section and the 4th section of change furnace section.CO conversion section work In the water vapour related in sequence and gas to be measured, the ratio (hereinafter referred to as vapor-air ratio) of remaining dry gas is shadow Ring one of important technological parameter of energy consumption and operational stability.

The assay method of traditional vapor-air ratio has condensation method, discharge method.Wherein, condensation method can only be discontinuously Measure vapor-air ratio.Vapour gas when discharge method can not meet vapor-air ratio wide variation and not add water vapour The needs that ratio is measured.In addition to above-mentioned traditional vapor-air ratio assay method, prior art also disclose many Plant vapor-air ratio and measure control instrument or assay method.Such as, prior art discloses a kind of carbon monoxide to become Steam ratio determination controller technology during changing, this technology can only measure the vapor-air ratio under special process, Special process refers to the shift process having saturator in CO conversion section operation, owing to saturator is to heat Recovery limited, and early stage equipment investment is big, therefore, under the form of current rapid industrial development, Replaced by new technology.Prior art also discloses steam and dry gas ratio measurement in a kind of interpolation steam course Instrument, this analyzer can be only used to measure steam-to-gas ratio in first paragraph change furnace section inlet water steam adding procedure The measurement of value, and for first paragraph change furnace section outside the vapor-air ratio of other change furnace section entrance can not survey Amount, i.e. for the vapor-air ratio related in chilling process of spraying water between change furnace section between first paragraph and second segment Can not measure.Prior art further relates to a kind of humidity method measuring water vapour and dry gas ratio, and the method can With measure multiple under the conditions of steam and dry gas ratio, but due to sensor performance limit for high temperature, high pressure Gas to be measured can only be drawn and be measured by situation, adds under measurement cost and existence conditions higher than 250 DEG C gas cannot measure.

Summary of the invention

For above-mentioned technical problem, the present invention provides the one can static and on-line determination and be capable of automatically connecting The continuous tandem synthesis ammonia plant conversion section each change furnace entrance vapor-air ratio measured measures system.

For solving above-mentioned technical problem, the technical solution used in the present invention is: a kind of tandem synthesis ammonia plant Conversion section each change furnace entrance vapor-air ratio measures system, and it includes the intelligent secondary meter of band communication function Group unit and gas composition analysis unit, be provided with temperature-adjusting device, temperature between two adjacent change furnace sections Control method is divided into interpolation steam, water spray cold shock and heat exchange；It is characterized in that: described mensuration system includes It is installed on the sensor group cells on each change furnace section of some series connection and pipeline, described sensor group cells bag Include before being arranged on described change furnace section to be measured anti-before measuring interpolation water vapour or cold shocking water in main pipeline Answer gas temperature and the sensor combinations of pressure in main pipeline, anti-after being used for measuring interpolation water vapour or cold shocking water Answer in main pipeline gas temperature and the sensor combinations of pressure and be arranged on for measure interpolation water vapour or For measuring the sensor combinations of cold shocking water or steam temperature and pressure in cold shocking water pipeline.

Described mensuration system also includes being arranged in described change furnace section to be measured or described conversion to be measured The hot(test)-spot temperature detection of the reaction hot(test)-spot temperature being made up of general purpose transducer in stove section previous change furnace section passes Sensor group.

Described gas composition analysis unit includes being arranged on synthesis ammonia plant transformation system entrance semiwater gas supervisor Semiwater gas analytical instrument on road, and it is arranged on described change furnace section change furnace the last period section to be measured The CO concentration analyzer of outlet.

Described intelligence secondary meter group unit includes for receiving the temperature that described sensor group cells collects A/D modular converter and CPU, CPU is included with the signal conditioning circuit of pressure signal, described signal conditioning circuit Output be respectively communicated with D/A modular converter, loop current output module, communication module, display module and Keyboard.Except be installed on transformation system entrance other described change furnace sections vapor-air ratio determinator can and Must be with the vapor-air ratio analyzer communication of change furnace section described in the last period to obtain change furnace described in the last period Section entrance vapor-air ratio thus draw the described change furnace section vapor-air ratio of to be measured section.

Semiwater gas analytical instrument in described gas composition analysis unit or CO concentration analyzer disappearance Time, use manual analysis and be manually entered in described intelligence secondary meter group unit by described keyboard So that measurement result is corrected.

Owing to taking above technical scheme, what it reached has the technical effect that owing to the present invention can be used for first paragraph Change furnace section, or it is simultaneously used in first paragraph change furnace section and second segment change furnace section, or it is simultaneously used for first paragraph Change furnace section, second segment change furnace section and the 3rd section of change furnace section, and so on, it is mountable to transformation series Whole change furnace sections of system, therefore, whether add steam at synthesis ammonia plant each change furnace section entrance and still spray Water or all can be obtained the vapor-air ratio of porch without any reaction mass by the present invention.

Accompanying drawing explanation

The invention will be further described below in conjunction with the accompanying drawings:

Fig. 1 is the overall structure schematic diagram of sensor of the invention group unit and gas composition analysis unit；

Fig. 2 is the overall structure schematic diagram of the intelligent secondary meter group unit of the present invention.

Detailed description of the invention

As shown in Figure 1 and Figure 2, a kind of tandem each change furnace of synthesis ammonia plant conversion section that the present invention provides Section entrance vapor-air ratio measures system and includes gas composition analysis unit, sensor group cells and intelligence secondary instrument Table group unit.Wherein, gas composition analysis unit includes being arranged on first paragraph change furnace section 1 entrance leading portion Semiwater gas analytical instrument 20, and it is arranged on the CO concentration analyzer of first paragraph change furnace section 1 outlet 21.Sensor group cells includes being arranged on first paragraph change furnace section 1 entrance leading portion main pipeline for measuring spray The temperature and pressure transmitter combination 3-0 of water or the gas temperature before adding steam and pressure, is arranged on for master On the pipeline of pipe water steam and for measuring the temperature pressure of the temperature and pressure of water vapour to be added Force snesor combination 3-1, is arranged on the main pipeline of pipeline rear mixed with water vapour for measuring dry gas The temperature and pressure transmitter combination 3-2 of the temperature and pressure of mixed gas, is arranged on first paragraph change furnace section 1 Temperature sensor 3-3 on the main pipeline of entrance, is arranged on the focus temperature on first paragraph change furnace section 1 outer wall Degree detection sensor group 3-4, the quantity of the sensor in hot(test)-spot temperature detection sensor group 3-4 is at least 3 Individual.

The mixed gas processed through first paragraph change furnace section 1 is delivered to second segment conversion through cold shock evaporimeter 4 In stove section 5, mixed gas is entering before cold shock evaporimeter 4 generally water spray Quench or add steam and process.This In a kind of tandem synthesis ammonia plant conversion section each change furnace entrance vapor-air ratio mensuration system that invention provides The sensor group cells related to also includes being arranged on to be responsible between first paragraph change furnace section 1 and cold shock evaporimeter 4 On road for measure enter cold shock evaporimeter 4 before without water spray cold haze or add the gas that steam processes Temperature and pressure temperature and pressure transmitter combination 3-5, be arranged on connection cold shock evaporimeter 4 pipeline on for Measure the temperature and pressure transmitter combination 3-6 of the temperature and pressure preparing cold shocking water or the water vapour added.Warp Cold shock evaporimeter 4 process after mixed gas by Pipeline transport to second segment change furnace section 5, cold shock evaporimeter It is provided for measuring mixed gas temperature and pressure on pipeline between 4 and second segment change furnace section 5 Temperature and pressure transmitter combination 3-7.Hot(test)-spot temperature detection is set on the furnace wall of second segment change furnace section 5 equally Sensor group 3-4, the quantity of the middle sensor of hot(test)-spot temperature detection sensor group 3-4 is at least 3.

As in figure 2 it is shown, intelligence secondary meter group unit is the computer system connecting sensor group cells, its Including the signal condition for receiving temperature, pressure signal and other signals that sensor group cells collects Circuit 6-0, signal conditioning circuit 6-0 include A/D modular converter 6-1 and CPU6-2, and CPU6-2's is defeated Go out end to be respectively communicated with D/A modular converter 6-3, loop current output module 6-4, communication module 6-5, show Show module 6-6 and keyboard 6-7.

When gas composition analysis unit lacks one or all instrument, use manual analysis and pass through keyboard 6-7 is manually entered in intelligence secondary meter group unit.Communication module 6-5 is used for obtaining change furnace section to be measured The vapor-air ratio of previous change furnace section entrance, provides basis for obtaining change furnace section entrance vapor-air ratio to be measured Data.

By the temperature of above-mentioned each temperature and pressure transmitter combination acquisition, pressure data and by gas composition analysis The gas-composition data that unit obtains, carries out following process final to obtain in intelligence secondary meter group unit Vapor-air ratio:

In water vapour and gas to be measured, the ratio calculation formula of remaining dry gas is:

$R=\frac{v_{H_{2}O}}{v-v_{H_{2}O}}=\frac{p_{H_{2}O}}{p-p_{H_{2}O}}---\left(1\right)$

In formula, v is volume of gas；For water vapour volume components；P is gas pressure；For water Vapor partial pressure.

If it is R that first paragraph change furnace section 1 enters stove vapor-air ratio₀, occur following anti-in first paragraph change furnace section 1 Should:

Above-mentioned reaction is equimolar exothermic reaction, its reaction equilibrium constant K_pFunction for temperature:

$\mathrm{Kp}=\exp (\frac{50250.163}{T}-0.0936\×\ln T+1.4555\×{10}^{-3}-2.4887\×{10}^{-7}{T}^2-6.2894)---\left(3\right)$

In formula, T=hot(test)-spot temperature+balanced loss functions, hot(test)-spot temperature is by being arranged on first paragraph change furnace section 1 furnace wall On hot(test)-spot temperature detection sensor group 3-4 in sensor measurement obtain, take the highest temperature of sensor measurement Degree is hot(test)-spot temperature；Balanced loss functions be chosen for method known to those skilled in the art, do not repeat them here.

And:

$\mathrm{Kp}=\frac{p_{c{o}_2}\·p_{H_2}}{p_{\mathrm{co}}\·p_{H_{2}O}}=\frac{(C+\mathrm{AXp})(D+\mathrm{AXp})}{(A-\mathrm{AXp})(B-\mathrm{AXp})}---\left(4\right)$

In formula,For the dividing potential drop of carbon dioxide in dry gas；p_coFor the dividing potential drop of carbon monoxide in dry gas；For The dividing potential drop of hydrogen in dry gas；X_pFor carbon monoxide balanced transformation rate, can ignore when oxygen content is the lowest.

If A, B, C, D are respectively the initial concentration of carbon monoxide, water, carbon dioxide and hydrogen, by gas Body composition analysis unit records, and also can be manually entered into intelligence secondary instrument by keyboard 6-7 when changing little Table group unit.

To X_pSolve equation (3) and (4) and set:

U=Kp (A+B) (C+D) (5)

W=Kp-1 (6)

V=KpAB-CD (7)

$q=\sqrt{U^2-4\mathrm{WV}}---\left(8\right)$

$\mathrm{Xp}=\frac{U-q}{2\mathrm{AW}}---\left(9\right)$

Mainly determined by Gas-making Process owing to entering furnace gases composition and be held essentially constant.So X_pMain by temperature Degree determines.

For judging hot(test)-spot temperature, insert in a change furnace section no less than three hot(test)-spot temperature detection sensings Device, one of them is change furnace section entrance, being evenly distributed in conversion catalyst layer of other.Work as hot(test)-spot temperature When the catalyst layer temperature that detection sensor detects is not higher than change furnace section inlet temperature, it is believed that be that first paragraph becomes Change the entrance of stove section 1；Otherwise, it is the entrance of subsequent conversion stove section.

If it is R that first paragraph change furnace section 1 exports vapor-air ratio₁:

$R_1=\frac{(1-\mathrm{Xp})}{(1+\mathrm{Xp})}{R}_0---\left(10\right)$

Between the outlet and the import of second segment change furnace section 5 of first paragraph change furnace section 1, for regulation temperature Reacting, with supplementary first paragraph change furnace section 1, the steam consumed, general employing cold shock is sprayed water or adds steam, root According to thermodynamics theorem and set:

In every 1 mole above-mentioned is worked off one's feeling vent one's spleen, it is mixed into X mole of water or steam, has had:

$\underset{P_{1i}{T}_i}{\overset{P_{m^i}{T}_m}{\∫}}C(p,t)\mathrm{dt}=18\·X({\mathrm{\ΔH}}_W-\mathrm{\Δ}{H}_m)---\left(11\right)$

In formula, P_miIt it is the dividing potential drop of i-th section of mixed each component gas of change furnace section；P_1iIt is i-th section of change furnace Section water spray or add the dividing potential drop of each component before steam；T₁For water spray or the temperature that adds the gas before steam；For water spray or the specific heat capacity that adds the mixed gas before steam, wherein Y_iSpray water or add steam The mole fraction of front each component；I=CO, CO2, H20, H2, C4H4, Ar, N2；(micro content component is to result shadow Ring little not considering).

ΔH_w=φ (P_w, T_w) it is the water or the enthalpy of steam added, wherein, P_wFor preparing the water of interpolation or the exhausted of steam To pressure, T_wFor preparing water or the temperature of steam added；ΔH_m=φ (P_m, T_m) it is the part water or steaming added Vapour enthalpy upon mixing, wherein, P_mFor the absolute pressure after interpolation part water or steam, T_mIt is mixed Gas temperature after conjunction.

WillΔH_w=φ (P_w, T_w)、ΔH_m=φ (P_m, T_m) substitute into equation 11, use repeatedly Solve X for method, add that the contribution of original steam has:

R=(1+R₁)·X+R₁ (12)

In formula, R is second segment change furnace section 5 entrance vapor-air ratio.

Embodiment: below with the first change furnace section 1 entrance in certain conversion of carbon monoxide in synthetic ammonia plant workshop section operation, This is described in detail as a example by the mensuration of two change furnace section 5 entrances and latter end change furnace section entrance vapor-air ratio Bright.

Embodiment 1:

First paragraph change furnace section 1 entrance vapor-air ratio measures: owing to first paragraph change furnace section 1 does not has leading portion yet Just there is no the transformationreation of formula (2), at this moment obtained first paragraph change furnace section by temperature sensor 3-3 measurement Temperature T0 of 1 entrance, hot(test)-spot temperature detection sensor group 3-4 be connected to entrance cooled coal gas pipeline a little at.This Invention becomes a kind of disclosed in prior art and adds steam and dry gas ratio measurer used mensuration in steam course Method, can record vapor-air ratio is R₀, and by this of fieldbus and second segment change furnace section 5 entrance Bright device communication.

Embodiment 2:

The vapor-air ratio of second segment change furnace section 5 entrance measures: by porch semiwater gas analytical instrument 20 obtain component Yi into furnace gases；Embodiment 1 obtains the vapor-air ratio of first paragraph change furnace section entrance R₀；Following reaction is there occurs in first paragraph change furnace section 1:

At this moment by inserting hot(test)-spot temperature detection sensor group 3-4 of catalyst layer；Temperature is chosen by comparing The temperature of high point is hot(test)-spot temperature T, substitutes into formula (3) with " T+ balanced loss functions " and is calculated K_p, then add Above formula (4)～(10) draw the vapor-air ratio that first paragraph change furnace section 1 exports.In first paragraph change furnace section Generally with regulation temperature and water vapour is increased by water spray cold shock between 1 and second segment change furnace section 5, this Bright by temperature and pressure transmitter combination 3-6 measurement cold shocking water or temperature Tw of water vapour and pressure Pw, logical Excess temperature pressure sensor combination 3-5 measures to swash without water spray and processes or add the gas temperature T1 that steam processes With pressure P1, measured temperature Tm and the P2 of the gaseous mixture after water spray by temperature and pressure transmitter combination 3-7, During generally P1 and P2 approximation, desirable P1=P2.It is calculated second segment by formula (11) and formula (12) to become Change the vapor-air ratio of stove section 5 entrance.

Measured into stove by the semiwater gas analytical instrument 20 being arranged on first paragraph change furnace section 1 entrance leading portion Each component of gas is: CO, 30.28%；CO₂, 8.35%；H₂, 38.47%；N₂, 21.3%；CH₄+ Ar, 1.2%；O₂, 0.4%；The mensuration system using the present invention to provide measures first paragraph change furnace section 1 with existing method Vapor-air ratio R₀=0.5, by hot(test)-spot temperature detection sensor group 3-4 measure each point temperature and pass through than Relatively taking temperature soprano is hot(test)-spot temperature T=420 DEG C, is transformed into moisture: A=20.19%；B=33.33%； C=5.57%；D=25.66%；N₂=14.20%；CH₄+ Ar=0.8%；O₂=0.27%.T+ balanced loss functions =420+30=450 DEG C.Obtained by formula (4)～(10): K_p=7.455；U=430.22；W=6.455；V=4873.79； Q=243.41；X_p=71.67%；R₁=0.1648.

Owing to evaporation of water latent heat is bigger, a small amount of water i.e. can reach the purpose of cooling, and major part is closed at present The cooling of ammonification factory change furnace section intersegmental gas all uses the mode of cold shock water spray.Below in the way of cold shock water spray Describe the vapor-air ratio of second segment change furnace section 5 entrance of the present invention in detail: obtained by sensor measurement T1=390 DEG C, P1=2.5MPa；Tw=30 DEG C, Pw=2.8MPa；Tm=250 DEG C.By formula (11) and (12) Obtain X=0.110；Finally obtain second segment and enter stove vapor-air ratio and be: R=0.2929.And by data by scene Bus passes to the 3rd change furnace section (not shown).

Embodiment 3:

Second segment change furnace section 5 entrance steam-to-gas ratio is obtained, due in second segment change furnace section 5 from embodiment 2 Do not spray water between outlet and the 3rd change furnace section entrance and add steam, so by formula (11) and (12) Obtain X=0；R only need to be obtained by above-mentioned algorithm₁, i.e. R=R₁Be the 3rd section enter stove vapor-air ratio.

It can be that professional and technical personnel in the field realize or use that above-mentioned embodiment is intended to illustrate the present invention, Above-mentioned embodiment is modified and will be apparent from for those skilled in the art, therefore this Invention includes but not limited to above-mentioned embodiment, any meets the claims or specification describes, and meets With principles disclosed herein and novelty, the method for inventive features, technique, product, each fall within this Within bright protection domain.

Claims (5)

1. tandem synthesis ammonia plant conversion section each change furnace entrance vapor-air ratio measures a system, and it includes Intelligent secondary meter group unit with communication function and gas composition analysis unit, between two adjacent change furnace sections Being provided with temperature-adjusting device, temperature control method is divided into interpolation steam, water spray cold shock and heat exchange；It is special Levy and be: described mensuration system includes being installed on the sensor group on each change furnace section of some series connection and pipeline Unit, before described sensor group cells includes being arranged on described change furnace section to be measured, main pipeline is interior for measuring React gas temperature and the sensor combinations of pressure in main pipeline before adding water vapour or cold shocking water, be used for measuring React in main pipeline gas temperature and the sensor combinations of pressure after adding water vapour or cold shocking water and be arranged on For measuring the biography of cold shocking water or steam temperature and pressure in measuring interpolation water vapour or cold shocking water pipeline Sensor combines；Can except the vapor-air ratio determinator of other the described change furnace sections being installed on transformation system entrance With and must and the last period described in the vapor-air ratio analyzer communication of change furnace section convert described in the last period to obtain Stove section entrance vapor-air ratio thus draw the described change furnace section vapor-air ratio of to be measured section.

2. tandem synthesis ammonia plant conversion section each change furnace entrance vapor-air ratio as claimed in claim 1 is surveyed Determine system, it is characterised in that: described mensuration system also include being arranged in described change furnace section to be measured or The heat of the reaction hot(test)-spot temperature being made up of general purpose transducer in described change furnace section previous change furnace section to be measured Point temperature detection sensor group, described general purpose transducer is that hot(test)-spot temperature detects sensor.

3. tandem synthesis ammonia plant conversion section each change furnace entrance vapor-air ratio as claimed in claim 1 is surveyed Determine system, it is characterised in that: described gas composition analysis unit includes that being arranged on synthesis ammonia plant transformation system enters Semiwater gas analytical instrument on mouth semiwater gas main pipeline, and it is arranged on described change furnace section to be measured The CO concentration analyzer of change furnace section outlet the last period.

4. tandem synthesis ammonia plant conversion section each change furnace entrance vapor-air ratio as claimed in claim 1 is surveyed Determine system, it is characterised in that: described intelligence secondary meter group unit includes for receiving described sensor group list The signal conditioning circuit of the temperature and pressure signal that unit collects, described signal conditioning circuit include that A/D changes Module and CPU, the output of CPU is respectively communicated with D/A modular converter, loop current output module, communication mould Block, display module and keyboard；Vapor-air ratio except other the described change furnace sections being installed on transformation system entrance Determinator can and must be previous to obtain with the vapor-air ratio analyzer communication of change furnace section described in the last period Duan Suoshu change furnace section entrance vapor-air ratio thus draw the described change furnace section vapor-air ratio of to be measured section.

5. tandem synthesis ammonia plant conversion section each change furnace entrance vapor-air ratio as claimed in claim 3 is surveyed Determine system, it is characterised in that: the semiwater gas analytical instrument in described gas composition analysis unit or CO During concentration analyzer disappearance, use manual analysis and by manual with the keyboard that intelligence secondary meter CPU is connected So that measurement result is corrected in input the most described intelligence secondary meter group unit.