CN1570802A - Adjusting device for heat value/caloric index and pressure of liquefied petroleum gas - Google Patents
Adjusting device for heat value/caloric index and pressure of liquefied petroleum gas Download PDFInfo
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- CN1570802A CN1570802A CNA2004100340565A CN200410034056A CN1570802A CN 1570802 A CN1570802 A CN 1570802A CN A2004100340565 A CNA2004100340565 A CN A2004100340565A CN 200410034056 A CN200410034056 A CN 200410034056A CN 1570802 A CN1570802 A CN 1570802A
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- gas
- air
- pressure
- liquefied petroleum
- lpg
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D21/00—Control of chemical or physico-chemical variables, e.g. pH value
- G05D21/02—Control of chemical or physico-chemical variables, e.g. pH value characterised by the use of electric means
Abstract
It is the liquefied petroleum gas heating value/Wobbe Index and pressure-adjusting apparatus. It belongs to measure equipment realm. It comprises measuring and pressure-adjusting apparatus of liquefied petroleum gas; measuring and pressure-adjusting apparatus of compressed air. They are connected to the volume controlling apparatus respectively, then combined and entered to the gas mixture apparatus, heating value control and regulating apparatus. The measuring and pressure-adjusting apparatus of liquefied petroleum gas installs on the one liquefied petroleum gas pipeline. The measuring and pressure-adjusting apparatus of compressed air installs on the other pipeline. These two pipelines are combined and entered the pressure control valve and pipeline mixer, after which is the mixed gas heating value meter and mixed gas manual butterfly valve. Then leading them to the sampling control system to adjust and control heating value. This apparatus mixes certain amount air's heating value/ Wobbe Index in the liquefied petroleum gas, so can control and adjust stably. And it can measure the error of various adjusting apparatus accurately.
Description
Technical field
The invention belongs to the measuring equipment field, particularly a kind of pressurized air that adds in liquefied petroleum gas (LPG) is with to liquefied petroleum gas (LPG) calorific value/China device of adjusting of index and pressure in vain.
Background technology
Liquefied petroleum gas (LPG) is as a kind of gaseous fuel, and the white index of its calorific value/China is greater than rock gas and coal gas, and saturated vapor pressure is lower at normal temperatures, is compressed into liquid state easily and grows the distance conveying, so that use in extensive area.
The pure liquefied petroleum gas (LPG) of gaseous state is with after air mixes according to certain ratio, its saturated vapor pressure can reduce greatly on the one hand, the easier liquid state that is compressed into, and be applicable to long distance conveying, can exchange with other combustion gas simultaneously, as peak regulation, bailout gas, transition source of the gas.
At present, in the prior art, liquefied gas mixes air and has three major types type one low-pressure injection formula, mechanical proportional valve formula and servo-actuated flow mixed-gas type.
The low-pressure injection formula: its principle of work is that combustion gas is penetrated with the nozzle of certain pressure from injector, makes the collapsible tube of injector produce negative pressure on every side, thereby air is sucked.Two kinds of gases mix at trunnion, enter the anemostat of injector then.Combination gas speed in anemostat reduces, and pressure increases.Its adopts be atmosphere as mixed diluting gas, utilize liquefied gas after the vaporization by venturi, injection air in certain amount.Send into the low pressure gas holder then, mixed gas is supplied with the user after the pressurization of pressurized equipment roots blower.This low pressure process exists following problem: (1) has increased floor area owing to gas holder is arranged as buffering.(2) roots blower operation noise is big, and the failure rate height is unfavorable for continuous operation, and top hole pressure can't improve, capacity can't dilatation.(3) manual adjustments blending ratio normally, it is low that calorific value is adjusted precision.(4) the injector technology Calculation is comparatively complicated, and efficient is low, the operating mode instability, and it is not very good mixing the gas effect.
Mechanical proportional valve formula: its principle of work is, a variable orifice T-valve generally fluctuates to change flow, and left-right rotation is to change mixing ratio.Promptly use earlier master and slave two pressure regulators, the pressure of two kinds of gases is adjusted to equal, make by the flow of T-valve proportional with the area in corresponding aperture.There is following point on this device busy principle:
(1), will cause control overshoot and to cause system oscillation to cause that the calorific value fluctuation is difficult to stable because the reaction type control device is adopted in the existence that calorific value detect to lag behind merely.
(2) when changing with gas load, be subjected to will lagging behind main voltage regulator from pressure regulator and moving of main voltage regulator control, make two kinds of gaseous tensions produce the inconsistent fluctuation of phase place, destroyed mixing ratio.Caused mixer calorific value when load variations to have than great fluctuation process.
(3) configuration of mixing valve inlet pressure regulator has increased the system pressure loss, in order to improve the top hole pressure of combination gas, will improve pressure for vaporization, and cause two ill effects: the heat interchanging area of 1 carburetor increases; 2 make the easier polymerization of unsaturated hydrocarbon in the liquefied petroleum gas (LPG), make easier being stuck of mixing valve movable part and influence mixture ratio.
(4) mixing valve is a special product, needs very accurate and complicated processing, has error just to have a strong impact on its performance slightly.Need repetition test in production and debug process, production quantity is few again, so delivery cycle is grown, cost an arm and a leg.And after the mixing valve moulding, its mixed ratio can not arbitrarily change.When the process conditions change needs to change the ratio of mixing, the mixed valve of necessary replacing, system suitability is very poor.
Servo-actuated flow mixed-gas type: in its work, though overcome the shortcoming of low-pressure injection formula, mechanical proportional valve formula, do not eliminated the fluctuation of the hysteresis of calorific value feedback, pure liquefied petroleum gas (LPG) calorific value, flow rate fluctuation three kinds of disturbance factors that the compressed air pressure temperature variation is brought to calorific value/China adverse effect of bringing of index in vain.
Prior art to sum up, several main type that liquefied gas mixes air all exists many deficiencies, therefore needs innovation ground develop a kind of novel device device, in order to index and pressure are effectively adjusted and controlled in vain to liquefied petroleum gas (LPG) calorific value/China.
Summary of the invention
The technical issues that need to address of the present invention are, in prior art, when liquefied gas mixes air, ratio is adjusted and calorific value is adjusted low precision, the process complexity, efficient is low, and if adopt mechanical proportional valve formula, not only mixing valve costs an arm and a leg, and blending ratio is difficult for careless the replacing, system flexibility is poor, simultaneously, what calorific value adjustment control was adopted is continuous control system, has caused the hysteresis and the instability of calorific value, in order to overcome above-mentioned many deficiencies, and redesign a kind of measuring equipment device, and to calorific value adjustment control selected for use sampled-data control system, this control system be with measurements and control action by sampling switch and zero-order holder, once sample and once adjusting every a sampling period, in order to realizing that liquefied petroleum gas (LPG) mixes the perfect condition of air, and with its calorific value/China index and pressure control effectively and adjust in vain.
Before describing concrete scheme, narrate the ultimate principle of this programme institute foundation earlier.The principle of work of apparatus of the present invention is, according to principle of energy balance, sneaks into air in certain amount in liquefied gas, with its energy dilution, makes and transfers the white index of back calorific value/China to stablize within the specific limits.
Its theoretical foundation is:
Q
lpg×F
lpg＝?Q
s0×(F
lpg+F
a)
In the formula:
Q
Lpg---liquefied gas calorific value, MJ/Nm
3
F
Lpg---flow of lpg, Nm
3/ Hr
Q
S0--the calorific value stationary value (desired value) of-combination gas, MJ/Nm
3
F
a---dilution necessary air mass flow, Nm
3/ Hr
According to above-mentioned principle, adopt isobaric mixing to add the static mixer mode, control air, combustion gas valve opening separately automatically, adjust its mixing ratio, after two kinds of gases mix, change direction through cone stator special in the line mixer.This cone stator is to form with the sword limit blade of band angle, make gas produce centrifugal motion, move, then at the gas outlet process eddy current destroyer second time along barrel, gas is exported by delivery channel, and gas becomes turbulent flow by original laminar flow and is able to even mixing.
By heat is transferred principle and systematic analysis, can see clearly that component, the flow of liquefied gas, the variation of air mass flow all can change the calorific value of mixer, and traditional reaction type regulator must be waited for that the heat vale of mixture process values departs from and just changes output behind the set-point, and the calorific value detection exists hysteresis, make its corrective action start late, and it can not provide an accurate output immediately the interference of corresponding certain amplitude, just on correct direction, sound out, consistent in the hope of the measured value of calorific value with set-point.This trial method has just caused the vibration of calorific value, if the frequency of disturbing is high slightly, this trial method is owing to sound out repeatedly back and forth, and it is stable that system is difficult to.The particularly existence of Zhi Houing makes the variation of calorific value not deliver to regulator in time, faithfully, make regulator still the delay signal when having crossed operate, cause lengthening transit time, overshoot increases.
For this reason, the eliminate the effects of the act various interference of calorific value of following improvement on control strategy, have been done respectively.
1. the pure hysteresis of adopting " controlling of sampling " to come the countermeasure calorific value to detect.
It is a continuous control system that traditional calorific value is adjusted control strategy, is characterized in receiving measuring-signal continuously at time domain adjusted device, and provides correction signal continuously.Controlling of sampling then is that it is measured and control action is once sampled and once adjusting every a sampling period by sampling switch and zero-order holder.
Detect for calorific value, be t the pure retardation time of supposing it, so any corrective action wants elapsed time t just can reflect later at least, conventional ratio, integration, differential regulator are controlled according to deviation, if t is very big, the signal no change that then feeds back for a long time, thereby regulator is inevitable excessive because of can not get feedback information to the correction for drift effect, integral action will make process produce serious hyperharmonic vibration; When not seeing effect when its output of regulator change in addition, continue its output of change just without any meaning.Therefore adopt " controlling of sampling " to understand to be exactly from control strategy " transfer, or the like see " thought and way.
2. adopt the spontaneous disturbance of " tandem control " countermeasure air mass flow
Cascade control system has two regulators: one is master selector, and one is secondary controller.The output of master selector is given as secondary controller.In the calorific value Adjustment System, adopt heat vale of mixture and air mass flow to form cascade control system, heat vale of mixture is as main controlled variable, and air mass flow is as secondary controlled variable.
It is very stable to suppose that heat vale of mixture maintains near the set-point, when spontaneous disturbance takes place in air mass flow, if do not change the air flow control valve opening, heat vale of mixture is certain to correspondingly change, because the hysteresis that calorific value detects adopts traditional control strategy then can not in time make correction.But after the subloop of tandem control is regulated, can play regulating action in time, make and disturb influence to weaken calorific value; If disturb very greatly when having influence on calorific value, the output of master selector begins to change, and to secondary controller, it will accept the variation of set-point and measured value two aspects, thereby input deviation is increased, and corrective action is strengthened, and has quickened adjustment process.
3. adopt the variation of " feedforward control " countermeasure liquefied gas component and flow
In the above-mentioned all kinds of control strategies of mentioning, regulator all is poor by set-point and measured value, promptly carries out work by deviation, and Here it is according to the control system of feedback principle work.But flow of lpg changes greatly when occurring, during the big interference of component variation, the quality of FEEDBACK CONTROL often can not be satisfactory.The method of a solution is introduced feedforward control exactly.Detect liquefied gas calorific value Q with a caloric value instrument
Lpg, detect flow of lpg F with flowmeter
LpgCan calculate out necessary air mass flow F according to following formula
a, go to make the air flow control valve to reach as the preset value of air flow control valve and preset aperture; When liquefied gas calorific value and/or flow of lpg change, the variation of necessary air mass flow can be reflected, thereby the aperture of air flow control valve can be changed, heat vale of mixture is played corrective action timely.
F
aBeing the feedforward amount, be the quantity of mixing air in former combustion gas owing to what adjust calorific value dependence, so controlled device is an air in the system.Control system is adjusted link by inside and outside two closed loops and is formed.The inner link of adjusting is a feedback quantity with the adjustment air mass flow of actual measurement and the difference of feedforward air mass flow, is finished adjusting the control of air capacity by controller PID2; Outside link is a feedback quantity with the calorific value of adjusted mixed gas and the difference of target fuel gases calorific value then, finishes online adjustment to the air capacity that feedovers by controller PID1.Inside and outside two links cooperate the error that can compensate various regulating devices.Add rational feedforward link, make system have good stable state and transient control precision.
Specifically, the objective of the invention is to rely on following technical scheme to realize, white index of a kind of liquefied petroleum gas (LPG) calorific value/China and pressure regulation device, comprise liquefied petroleum gas (LPG) metering and regulator, pressurized air metering and regulator, and be connected respectively to volume control device, remerge and enter gas mixer, calorific value control adjusting gear, it is characterized in that, this liquefied petroleum gas (LPG) metering and adjusting gear are arranged on one road liquefied petroleum gas (LPG) pipeline, and it includes the liquefied gas Hand-operated butterfly valve, valve, flow of lpg meter are sent in the gas pressure change; Follow the liquid gas flow amount control device that liquefied gas temperature thermal resistance and liquefied gas retaining valve are constituted thereafter; Being arranged on another road pipeline is compressed air require and regulator, and it includes air Hand-operated butterfly valve, air pressure transmitter, air flowmeter; Follow air themperature thermal resistance and air-flow control device that air check valve constituted thereafter; The merging of two-way pipeline enters pressure control valve and line mixer, is connecting heat vale of mixture instrument and combination gas Hand-operated butterfly valve thereafter; Again it is connected to sampled-data control system and carries out calorific value adjustment control.
The invention has the beneficial effects as follows, this device obtains stable control and adjustment, and can accurately measure its flow, pressure for the white index of calorific value/China of sneaking into a certain amount of air in the liquefied gas, compensate the error of each regulating device, make system that the good stable state and the control accuracy of transient state be arranged.
Description of drawings
Fig. 1 is formation and each process portion annexation figure of apparatus of the present invention
Fig. 2 is the schematic diagram of controlling of sampling
Fig. 3 is the calorific value regulating and controlling system principle diagram of apparatus of the present invention
Among the figure: liquefied gas Hand-operated butterfly valve 1.1, air Hand-operated butterfly valve 2.1, gas pressure transmitter 1.2, air pressure transmitter 2.2, flow of lpg meter 1.3, air flowmeter 2.3, liquefied gas temperature thermal resistance 3.1, air themperature thermal resistance 4.1 liquefied gas retaining valves 3.2, air check valve 4.3, pressure control valve 5 flowrate control valves 4.2 liquefied gas caloric value instruments 7 heat vale of mixture instrument 8 combination gas Hand-operated butterfly valves 9 line mixers 6.
Embodiment
With reference to Fig. 1, formation and each process portion annexation synoptic diagram of expression apparatus of the present invention, liquefier caloric value instrument 7 among the figure, measure the liquefied petroleum gas (LPG) calorific value after the vaporization, with flow of lpg meter 1.3, gas pressure transmitter 1.2, the flow that liquefied gas temperature thermal resistance 3.1 is measured under the liquefied gas status of criterion, signal is sent in the process controller by liquefied gas retaining valve 3.2 and is by formula performed calculations, calculate necessary air capacity signal removes to control air flow control valve 4.2 as the preset value of flowrate control valve 4.2 aperture, with air flowmeter 2.3, air pressure transmitter 2.2, air themperature thermal resistance 4.1 is measured the flow under the standard air situation, send in the process controller pressure control valve 5 by flowrate control valve 4.2 and air check valve 4.3, make actual air flow conform to necessary air capacity, thereby liquefied gas is mixed with certain ratio with air, obtain the combination gas of certain calorific value by line mixer 6.
Measure the calorific value of combination gas with heat vale of mixture instrument 8, by 9 outputs of combination gas Hand-operated butterfly valve, after deviation appears in heat vale of mixture and target setting value, PID by process controller regulates, combine with necessary air capacity, export the aperture that a control signal changes flowrate control valve 4.2, strengthen or the minimizing air capacity, make calorific value maintain the target setting value.
The load of this device (pressure) is regulated, and realizes by process controller controlled pressure operation valve 5.
Claims (4)
1. white index of liquefied petroleum gas (LPG) calorific value/China and pressure regulation device, comprise liquefied petroleum gas (LPG) metering and regulator, pressurized air metering and regulator, and be connected respectively to volume control device, remerge and enter gas mixer, calorific value control adjusting gear, it is characterized in that, this liquefied petroleum gas (LPG) metering and adjusting gear are arranged on one road liquefied petroleum gas (LPG) pipeline, and it includes liquefied gas Hand-operated butterfly valve, gas pressure transmitter, flow of lpg meter; Follow the liquid gas flow amount control device that liquefied gas temperature thermal resistance and liquefied gas retaining valve are constituted thereafter; Being arranged on another road pipeline is compressed air require and regulator, and it includes air Hand-operated butterfly valve, air pressure transmitter, air flowmeter; Follow air themperature thermal resistance and air-flow control device that air check valve constituted thereafter; The merging of two-way pipeline enters mixture pressure operation valve and line mixer, is connecting heat vale of mixture instrument and combination gas Hand-operated butterfly valve thereafter; Again it is connected to sampled-data control system and carries out calorific value adjustment control.
2. white index of liquefied petroleum gas (LPG) calorific value according to claim 1/China and pressure regulation device, it is characterized in that, described sampled-data control system, form by sampling switch and zeroth order retainer, adjust link work by inside and outside two closed loops, inner PID2 finishes the control of adjusting air capacity, and outside PID2 finishes the online adjustment to the feedforward air capacity, and inside and outside link cooperates the various regulating device errors of compensation.
3. white index of liquefied petroleum gas (LPG) calorific value according to claim 1/China and pressure regulation device is characterized in that described mixing arrangement adopts the duct type static mixer.
4. according to white index of claim 1 and 3 described liquefied petroleum gas (LPG) calorific value/China and pressure regulation device, it is characterized in that having the sword limit blade of band angle in the described duct type static mixer, gas is produced along the tube wall centrifugal motion.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2004100340565A CN100480939C (en) | 2004-04-23 | 2004-04-23 | Adjusting device for heat value/caloric index and pressure of liquefied petroleum gas |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2004100340565A CN100480939C (en) | 2004-04-23 | 2004-04-23 | Adjusting device for heat value/caloric index and pressure of liquefied petroleum gas |
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| Publication Number | Publication Date |
|---|---|
| CN1570802A true CN1570802A (en) | 2005-01-26 |
| CN100480939C CN100480939C (en) | 2009-04-22 |
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|---|---|---|---|
| CNB2004100340565A Expired - Fee Related CN100480939C (en) | 2004-04-23 | 2004-04-23 | Adjusting device for heat value/caloric index and pressure of liquefied petroleum gas |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102937240A (en) * | 2012-10-26 | 2013-02-20 | 西安东风机电有限公司 | Back pressure control method and application system for liquefied gas loading |
| CN106287804A (en) * | 2015-05-29 | 2017-01-04 | 西门子（中国）有限公司 | Combustion control system |
| CN107237981A (en) * | 2017-06-23 | 2017-10-10 | 成都深冷液化设备股份有限公司 | The calorific value and Wobbe index adjusting means and method of gas engine fuel gas |
| CN111288297A (en) * | 2020-02-12 | 2020-06-16 | 首钢集团有限公司 | Coal gas hybrid system |
-
2004
- 2004-04-23 CN CNB2004100340565A patent/CN100480939C/en not_active Expired - Fee Related
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102937240A (en) * | 2012-10-26 | 2013-02-20 | 西安东风机电有限公司 | Back pressure control method and application system for liquefied gas loading |
| CN106287804A (en) * | 2015-05-29 | 2017-01-04 | 西门子（中国）有限公司 | Combustion control system |
| CN106287804B (en) * | 2015-05-29 | 2019-01-04 | 西门子（中国）有限公司 | combustion control system |
| CN107237981A (en) * | 2017-06-23 | 2017-10-10 | 成都深冷液化设备股份有限公司 | The calorific value and Wobbe index adjusting means and method of gas engine fuel gas |
| CN107237981B (en) * | 2017-06-23 | 2023-12-05 | 四川蜀道装备科技股份有限公司 | Device and method for adjusting calorific value and white index of fuel gas of gas engine |
| CN111288297A (en) * | 2020-02-12 | 2020-06-16 | 首钢集团有限公司 | Coal gas hybrid system |
| CN111288297B (en) * | 2020-02-12 | 2021-12-21 | 首钢集团有限公司 | Coal gas hybrid system |
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| Publication number | Publication date |
|---|---|
| CN100480939C (en) | 2009-04-22 |
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Granted publication date: 20090422 Termination date: 20100423 |