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Variable frequency speed control technology in the application of heating peak load boiler and discussion

Release time:2016-01-05 23:53:59
Author: Song Jingfa (19,681) male, University degree, senior engineer, Mudanjiang city, Heilongjiang province, West side heating company working since 1991 to participate in its work, has been engaged in the design, installation, commissioning and operation of heating boilers research.
Peak regulation of variable frequency speed control technology in heating boilers inthe application and discussion of Song Jingfa, Hanyu (heating company in the West, Mudanjiang, Mudanjiang 157003) applied in heating peak load boiler and explore, achieve the goal of high efficiency and energy saving.
Boiler drums, ~6 190kW,7 9 boiler induced draft fan motor capacity drum, fan motor capacity of 340kW. equipped with 4 boiler feed pumps, motor capacity to 260kW,630kW, (2), 800kW, together with other auxiliary pumps, boiler water pump, fan motor 3905kW 90% per cent of total consumption of boiler room. Each visit 1 cut off the statement in today's development and design of new type boiler, high efficiency, coal boiler Designer, energy-saving, environmental protection has become the inevitable target. Which, in solution boiler original design in the exists boiler with wind machine, and pump of design thought old, and selection improper, and rich volume had big, and actual work points away from best work points, and run efficiency low problem Shi, has energy-saving rate high, and recovered investment fast, variety advantages of frequency adjustable speed technology has application to boiler design in the, although has received has obviously of economic, but its brings energy-saving effect is by no means just Yu this.
I have 2 variable frequency speed adjusting energy saving instances heating peak load boiler 9, in which the 1~6 furnace fan power consumption of 11 million cost of nearly 7 million Yuan, energy consumption can be seen.
In order to make energy efficiency, promote the development of enterprise, our company's various energy-saving measures have been carried out, and at the end of 2002 to * SHW4fr1* * DHL2 plants sprouting 1*6/150/90A11 type furnace (that is 2 West hotel boilers) fan frequency conversion speed regulating device is installed andput into use. To validation 9 boiler received of effect, we take another a Taiwan while installation, and using of with type boiler (that West 8 boiler) for has rough test compared, as table 1. table 1 frequency, and workers frequency run situation table (November 11, 2002 16 equipment name rated power kW average current a, average hot power MW hours power kWh output heat GJ electric single consumption kWi/GJ relative saving rate 9 furnace introduction wind motor (frequency) blast motor 8 furnace introduction wind motor (workers frequency) blast motor and 8 furnace compared, 9 furnace in output hot power same of situation Xia each hours saving: volume has cannot completely separate Dang pot boiler of load change Shi Le requirements sent *lishil should regulation Taiwan pump cannot meet flow or when needed opened or stopped open bookmark3 56019.6=2.9 (months/Taiwan) with similar of method also on 2 boiler for has rough test, in output hot power same of situation Xia, saving rate also reached 29.4% can see, saving rate with motor capacity of increased and increased.
3 energy saving analysis and discussion 3.1 frequency converter energy saving analysis of fans can be seen from the above examples, energy saving effect of variable frequency fan ideal.
Energy-saving principle of frequency conversion fans: characteristic of the fan is a fan at a certain speed and under certain conditions of medium density, its full pressure h, consumed power n and n efficiency relationships with air flow rate Q. The characteristics of smoke, the air is smoke, wind resistance and the relationship between the air flow. Smoke, wind resistance rapidly increases with the increase of air, and is available under said curve with smoke, air duct fan total pressure characteristic curveof intersection, is a work of fan points. Work points should meet following conditions: design work points of air should is equal to boiler highest load Xia of smoke, and air, this is boiler on ventilation machine of basic requirements; second, work points should in wind machine of highest efficiency district, to guarantee wind machine work of economic sex; work points of wind pressure up with overcome smoke, and duct resistance, guarantee flow of role, wind pressure and wind and introduction air for corresponding of change. But as the pressure generated by the wind turbine with theair volume changes gradually, smoke, air duct resistance changes quite dramatically,and their change trend is contrary to the Basic. So as soon as the winds native workof point deviation from the design, air flow imbalance between supply and demandis growing, balance adjustment measures must therefore be taken to. At this time, compared with constant speed fan throttle, the advantages of variable-frequency adjustable-speed fans immediately displayed, such as.
When constant fan design 1 transfer to the new point 2 o'clock, fan pressure depends on the throttle until the bezel to equilibrium with the smoke, wind resistance, ventilation from Q, change to the desired air flow rate Q2 loss. If using frequency conversion speed from *1 to reduce the 2 o'clock, from 1 to the corresponding volume also decreased from Qi to Q2% pressure loss could be saved, saving a total pressure loss AH1+AH2. greatly reduced power output can be drawn, and fan work in high efficiency, achieve the purpose of saving.
3.2 variable speed pumps in parallel operation of heating during the winter becauseof seasonal changes in day and night, heat load changeable, increase one by one bythe beginning of the heating boiler to the boiler by reducing peak. Boiler flow required by the sleek curves of phase 1 is the required heat load curves, but the heat loadcurve is the actual output as 2 diagonal stepped curve in some of the energy is wasted. Also, different types, different speed constant-speed pumps operating in parallelproblem is exposed, when one of the pumps in the best working point, while the second pump must deviate from work, decreased productivity, increased output shaft,power consumption is increased, it is not economic, such as.
From can see, CE for pipeline curve, it and pump parallel run total performance curve of intersection a,, is parallel run of work points, its flow for Qa, pressure head for Ha, it representative joint run of eventually effect; had a, points for level dashed and the pump performance curve make Yu Di and D2, they representative participate in joint run Shi each Taiwan pump by "contribution" workers condition, their by provides of flow is Qi and Q2 their by for pressure head are for Ha. but this species way whether economic reasonable efficient, to through research the pump of efficiency and set. For example, when CE is pipeline performance curves, both the working pointof the pump the pump Di efficiency for Ei with corresponding to D2 52. Bi then pump is the most efficient work under Ei, and B2 does not run under the maximum efficiency of a pump. At which the pipeline to CE', corresponding to the working point ofthe pump Bi di EI efficiency is lower than its maximum efficiency, and B2 are the most efficient work under *2. Obviously, two pumps at the same time achieve high efficiency energy-saving is not possible.
Two parallel operation condition of variable-frequency adjustable-speed pump in contrast, when operating in parallel after the required pressure or the flow rate is given, two pumps can be changed by changing the speed of the respective pump pressure or flow, making each move closer to the target value of performance parameters, and you can also adjust to their efficient work area. This situation is similar to thesame type and speed pump in parallel operation when operating conditions are high efficiency and energy saving.
3.3 application to the microcomputer automatic control system from the foregoing,frequency conversion technology applied in artificial control of peak shaving boiler,has achieved remarkable energy saving effect. However, their energy level contain artificial subjective factor, after all, the manual changing frequency is limited. When you apply it to the micro-computer control system, more value, such as.
Outdoor temperature t of the collection and heat supply area of the input data intocomputer data processing software system, heating curve is plotted, calculate the instantaneous heating. Based on the calculated value (you can also set) as the independent variable transmitted to the selection of pumps and flow control system, frequency converter to perform operations, numerical condition of pump required flow function; on the boiler can be set according to each boiler parameters prompt option, the furnace load distribution. After a restart the furnace to a stable state, automatically cut to the load control system of the boiler. Introduction based on thickness of coal-fired boiler load feedforward, burning coal layer thickness for the air flow based on feedforward, real-time monitoring based on the boiler flue gas oxygen excessair ratio of feed, boiler controller on drums, induced draft fan motor Inverter control, realization of the boiler load, automatic adjustment of air flow.
To note is that data must meet conditions set: design parameters within mature andreliable empirical data; alarm and interlock control function.
4 closing frequency adjustable speed technology application to similar I company of this load changes big of adjustable peak boiler in the, not only will save large of power, and can greatly reduce Stokers of intensity; can timely adjustment burning workers condition, real do boiler burning of "fine-tuning", makes burning always in best workers condition; improve has boiler efficiency; helps solution environmental problem; can adapted boiler other aspects of energy-saving transformation, as layered cloth coal, and heated surface blow gray transformation,; helps found and excluded boiler fault, as wind, and smoke road leak And the area of heating coking or serious fouling, high exhaust gas temperature; boiler subject to geographical restrictions and other problems, improving management level of heating boilers. Frequency conversion speed adjustment technology is difficult to implement, but its prospects are very positive.