CN105894762A - Dynamic early warning method for growing of dirt of reclaimed water heat exchanger - Google Patents

Abstract

The invention discloses a dynamic early warning method for the growing of the dirt of a reclaimed water heat exchanger, and the method comprises three parts: 1, carrying out the fitting of a heat transfer criterion equation of two sides of the heat exchanger in a clean state through data sampling; 2, carrying out the plotting of a dirt thermal resistance increase characteristic curve through the collection of the data of the reclaimed water heat exchanger in one operation period, and building a dirt thermal resistance increase mathematical model; 3, carrying out the dirt growing early warning of the next period through employing the dirt thermal resistance increase characteristic curve and the dirt thermal resistance increase mathematical model, which are obtained in a former period, and carrying out online updating. The method can achieve the early warning of the growing of dirt, can achieve the online updating, provides decision making basis for the operation and maintenance of the heat exchanger through the early warning of the growing of dirt in the next period, and can enable the reclaimed water heat exchanger to operate in an energy-saving and efficient manner.

Description

A kind of recycled water heat exchanger fouling growth dynamic early-warning method

Technical field

The invention belongs to HV&AC engineering field, particularly relate to a kind of recycled water heat exchanger fouling growth dynamic Method for early warning.

Background technology

Recycled water refers to that sewage, after suitably processing, reaches certain water quality index, can carry out useful use Water.At field of heating ventilation air conditioning, generally utilize heat exchanger to obtain heat from recycled water or cold meets people Use demand.But owing to recycled water water quality is poor, cause the easy dirt of recycled water heat exchanger so that it is heat transfer There is substantially deterioration in performance.In order to reduce the dirt impact for recycled water heat exchanger heat-transfer performance, need the palm Hold the fouling growth situation of recycled water heat exchanger, in order to be carried out scale removal in time.

Monitoring currently, with respect to recycled water heat exchanger dirtiness resistance is all to use detection, Threshold Alerts in real time Method, i.e. by real-time data acquisition, calculates real-time dirtiness resistance, then carries out with the threshold value set Contrast decides whether scale removal.Such as, and Chinese patent application (application number: 200510028159.5, entitled " dirtiness resistance real time on line monitoring control device and method ") disclose a kind of dirtiness resistance real time on-line monitoring Control device, gather data by signals collecting assembly, utilize Programmable Logic Controller to calculate real-time thermal resistance value also Control dosing assembly operating.Although this realtime on-line monitoring method can detect in real time dirtiness resistance value, Carry out scale removal warning, but it does not possess warning function, it is impossible to realize the decision-making in advance running, safeguarding, sending out When going out alarm signal, dirtiness resistance has reached high value, and scale removal process in addition has hysteresis quality, will make heat exchange The heat transfer property of device is substantially reduced, and is unfavorable for that the efficient energy-saving of heat exchanger runs.It addition, it is negative in actual motion Lotus rate and the isoparametric change of flow velocity will affect the heat transfer property of heat exchanger, and dirt be grown in each cycle Can there is certain diversity, and the method that real-time online detection calculates cannot realize computation model online the most more Newly, may cause detecting the fouling growth thermal resistance calculated and there is relatively large deviation with actual value, produce erroneous judgement.

Summary of the invention

For defect or deficiency present in prior art, it is an object of the invention to provide one and can realize dirt Predict and can carry out the recycled water heat exchanger fouling growth dynamic early-warning method of online updating.

In order to realize above-mentioned task, the present invention takes following technical solution:

A kind of recycled water heat exchanger fouling growth dynamic early-warning method, including following three partial contents:

Part I: simulate the formula for heat transfer of heat exchanger both sides under clean state by data sampling；

Part II: by the data acquisition to one cycle of operation of recycled water heat exchanger, draws dirtiness resistance Rising characteristic curve, set up dirtiness resistance increase mathematical model；

Part III: utilize the dirtiness resistance growth curve and mathematical model that the previous cycle obtained to next week Phase carries out fouling growth early warning, and carries out online updating；

Described Part I, follows these steps to carry out:

(1) in two side liquids of recycled water heat exchanger, arrange temperature, flow velocity harvester, gather required temperature Degree, flow parameters；

(2) heat transfer Correlation equations in recycled water side isWherein A_r、m_rIt is respectively as treating The criterion equation coefficient of matching and reynolds number Re_rIndex, according to surveyed data simulate recycled water side heat transfer Criteria equation；

(3) heat transfer Correlation equations in intermediary's water side isWherein A_c、m_cIt is respectively Treat criterion equation coefficient and the reynolds number Re of matching_cIndex, according to surveyed data simulate intermediary's water side pass Hot criteria equation.

Described Part II, follows these steps to carry out:

(1) by data acquisition unit, heat collecting exchanger recycled water side is into and out of temperature, in heat collecting exchanger Jie's water side is into and out of temperature, heat collecting exchanger recycled water effluent speed, heat collecting exchanger intermediary water effluent speed；

(2) Nu of recycled water side is calculated respectively by the temperature collected, flow speed data_rWith intermediary's water side Nu_c；

(3) by Nu_r=h_rd_e/ λ calculates recycled water side convection transfer rate h under clean state_r, by

Nu_c=h_cd_e/ λ calculates intermediary's water side convection transfer rate h under clean state_c；

(4) byCalculate dirtiness resistance R_f, wherein K is that recycled water heat exchanger always passes Hot coefficient, R_WFor recycled water heat exchanger wall thermal conduction resistance；

(5) dirtiness resistance value R corresponding to θ each time of running is recorded_f ^*=R_f；

(6) described recycled water heat exchanger dirtiness resistance R is drawn_f ^*Rising characteristic curve；

(7) set up described recycled water heat exchanger dirtiness resistance and increase mathematical model.

Described Part III, follows these steps to carry out:

(1) utilize the recycled water heat exchanger dirtiness resistance model of growth set up, calculate the heat exchanger in next cycle Dirtiness resistance early warning value R_f ^*；

(2) dirtiness resistance early warning value R is checked_f ^*With dirtiness resistance alarming value R_{fm a x}Relation, if:

R_f ^*≥R_fmax, carry out dirt warning or directly initiate apparatus for eliminating sludge；If:

R_f ^*＜ R_fmax, the most do not carry out dirt warning or stop scale removal；

(3) by data acquisition unit, heat collecting exchanger recycled water side is into and out of temperature, in heat collecting exchanger Jie's water side is into and out of temperature, heat collecting exchanger recycled water effluent speed, heat collecting exchanger intermediary water effluent speed；

(4) Nu of recycled water side is calculated respectively by the temperature collected, flow speed data_rWith intermediary's water side Nu_c；

(5) by Nu_r=h_rd_e/ λ calculates recycled water side convection transfer rate h under clean state_r, by Nu_c=h_cd_e/ λ calculates intermediary's water side convection transfer rate h under clean state_c；

(6) byCalculate dirtiness resistance R_f, wherein K is that recycled water heat exchanger is total Heat transfer coefficient, R_WFor recycled water heat exchanger wall thermal conduction resistance；

(7) dirtiness resistance value R corresponding to θ each time of running is recorded_f ^*=R_f；

(8) described recycled water heat exchanger dirtiness resistance R is drawn_f ^*Rising characteristic curve；

(9) described recycled water heat exchanger dirtiness resistance model of growth is revised, using revised model as next The Early-warning Model of cycle of operation.

The recycled water heat exchanger fouling growth dynamic early-warning method of the present invention, having the technical effect that of bringing is passed through Actual operating data collection to a cycle of operation, it is thus achieved that dirtiness resistance rising characteristic curve is simulated Dirtiness resistance model of growth, more conforms to actual operating mode；According to the data in previous cycle, simulate down The forecast model in one cycle, it is achieved that online updating, makes predictive value more accurate；By the dirt to next cycle Dirt growing state early warning, operation, maintenance for heat exchanger provide decision-making foundation, can shift to an earlier date the fortune of heat exchanger Row is intervened timely and effectively, can efficiently solve the recycled water heat exchanger heat-transfer performance that fouling growth causes Serious deterioration problem, can make recycled water heat exchanger keep efficient energy-saving to run.

Accompanying drawing explanation

Fig. 1 is that the data acquisition unit of the embodiment of the present invention 1 arranges schematic diagram；

Fig. 2 is the 1st the cycle of operation dirtiness resistance model of growth Establishing process figure of the present invention；

Fig. 3 is the 2nd of the present invention the, 3,4 ... cycle of operation working-flow figure.

Labelling in figure represents respectively: 1, recycled water broad passage plate heat exchanger, 2, recycled water inlet temperature Sensor, 3, recycled water outlet temperature sensor, 4, intermediary's water inlet temperature sensor, 5, intermediary's water goes out Mouthful temperature sensor, 6, recycled water outlet flow sensor, 7, intermediary's water out flow transducer.

Below in conjunction with drawings and Examples, the present invention is described in further detail.

Detailed description of the invention

In the following description, parameter Nu in the formula related to, Re, Pr, d_e, λ textbook " pass Calorifics " in be all defined, subscript r represents recycled water side parameter, and subscript c represents intermediary's water side parameter.

The present embodiment provides a kind of fouling growth dynamic early-warning method of regenerated water plate type heat exchanger, and as this Inventive embodiment 1.

Data acquisition unit is arranged as it is shown in figure 1, in Fig. 1, arrow represents the flow direction of fluid in pipeline, mark Biao Shi not score: 1, plate type heat exchanger, 2, recycled water inlet temperature sensor, 3, recycled water outlet temperature Sensor, 4, intermediary's water inlet temperature sensor, 5, intermediary's water outlet temperature sensor, 6, recycled water goes out Mouthful flow transducer, 7, intermediary's water out flow transducer.

The fouling growth dynamic early-warning method of regenerated water plate type heat exchanger that this embodiment describes, specifically include with Lower three partial contents:

Part I: simulate the formula for heat transfer of heat exchanger both sides under clean state by data sampling；

Part II: by the data acquisition to one cycle of operation of recycled water heat exchanger, draws dirtiness resistance Rising characteristic curve, set up dirtiness resistance increase mathematical model；Part III is, utilizes the previous cycle to be obtained The dirtiness resistance growth curve obtained and mathematical model carry out fouling growth early warning to next cycle, and carry out online Update, for the operation of heat exchanger in next cycle, safeguard offer decision-making foundation.

Described Part I is, is simulated the heat transfer criterion of heat exchanger both sides under clean state by data sampling Equation, comprises the following steps:

(1) the recycled water entrance at recycled water broad passage plate heat exchanger 1 arranges temperature sensor 2, regeneration Water out arranges that temperature sensor 3, intermediary's water inlet arrange that temperature sensor 4, intermediary's water out arrange temperature The outlet of sensor 5, recycled water arranges that flow transducer 6, intermediary's water out arrange flow transducer 7, gathers Temperature required, flow parameters；

(2) heat transfer Correlation equations in recycled water side isWherein A_r、m_rIt is respectively Treat criterion equation coefficient and the reynolds number Re of matching_rIndex, according to surveyed data simulate recycled water side pass Hot criteria equation

(3) heat transfer Correlation equations in intermediary's water side isWherein A_c、m_cIt is respectively Treat criterion equation coefficient and the reynolds number Re of matching_cIndex, according to surveyed data simulate intermediary's water side pass Hot criteria equation

Described Part II is, by the data acquisition to first cycle of operation of recycled water heat exchanger, draws Dirtiness resistance rising characteristic curve, set up dirtiness resistance increase mathematical model, its flow process as in figure 2 it is shown, tool Body follows these steps to:

(1) by data acquisition unit, heat collecting exchanger recycled water side is into and out of temperature, in heat collecting exchanger Jie's water side is into and out of temperature, heat collecting exchanger recycled water effluent speed, heat collecting exchanger intermediary water effluent speed；

(2) Nu of recycled water side is calculated respectively by the temperature collected, flow speed data_rWith intermediary's water side Nu_c；

(3) by Nu_r=h_rd_e/ λ calculates recycled water side convection transfer rate h under clean state_r, by Nu_c=h_cd_e/ λ calculates intermediary's water side convection transfer rate h under clean state_c；

(4) byCalculate dirtiness resistance R_f, wherein K is that recycled water heat exchanger is total Heat transfer coefficient, R_WFor recycled water heat exchanger wall thermal conduction resistance；

(5) dirtiness resistance value R corresponding to θ each time of running is recorded_f ^*=R_f；

(6) dirtiness resistance R measured by_f ^*Rising characteristic curve include initial phase, trophophase and progressive phase In three stages, meet asymptotic dirt model of growth,Wherein R '_fFor dirtiness resistance Stationary value, θ_cReach the time of stationary value for dirtiness resistance, θ is dirtiness resistance rise time；

(7) set up described recycled water broad passage plate heat exchanger dirtiness resistance increase mathematical model:

${R_f}^{*}=4.5\×{10}^{-4}\[1-\exp (-\frac{\mathrm{\θ}}{12.52})\].$

Described Part III is, utilizes dirtiness resistance growth curve that the previous cycle obtained and mathematical model to enter Row fouling growth early warning, and realize online updating, its workflow is as it is shown on figure 3, specifically follow these steps to:

(1) utilize the recycled water heat exchanger dirtiness resistance model of growth set up, calculate the heat exchanger in next cycle Dirtiness resistance early warning value R_f ^*；

(2) dirtiness resistance early warning value R is checked_f ^*With dirtiness resistance alarming value R_fmaxRelation, if:

R_f ^*≥R_fmaxCarry out dirt warning or directly initiate apparatus for eliminating sludge, if:

R_f ^*＜ R_fmaxThe most do not carry out dirt warning or stop scale removal；

(3) by data acquisition unit, heat collecting exchanger recycled water side is into and out of temperature, in heat collecting exchanger Jie's water side is into and out of temperature, heat collecting exchanger recycled water effluent speed, heat collecting exchanger intermediary water effluent speed；

(4) Nu of recycled water side is calculated respectively by the temperature collected, flow speed data_rWith intermediary's water side Nu_c；

(5) by Nu_r=h_rd_e/ λ calculates recycled water side convection transfer rate h under clean state_r, by Nu_c=h_cd_e/ λ calculates intermediary's water side convection transfer rate h under clean state_c；

(6) byCalculate dirtiness resistance R_f, wherein K is that recycled water heat exchanger is total Heat transfer coefficient, R_WFor recycled water heat exchanger wall thermal conduction resistance；

(7) dirtiness resistance value R corresponding to θ each time of running is recorded_f ^*=R_f；

(8) described regenerated water plate type heat exchanger dirtiness resistance R is drawn_f ^*Rising characteristic curve；

(9) revise described regenerated water plate type heat exchanger dirtiness resistance model of growth, using revised model as The Early-warning Model of next cycle of operation.

It should be noted that the embodiment of the fouling growth dynamic early-warning method of above-mentioned recycled water heat exchanger does not limits In regenerated water plate type heat exchanger, the most applicable for other type of heat exchanger and other working media, this The technical staff in field simply increasing and replacing, all in the present invention on the basis of technical scheme The row of protection domain.

Claims (1)

1. a recycled water heat exchanger fouling growth dynamic early-warning method, it is characterised in that include following three Partial content:

Part I: simulate the formula for heat transfer of heat exchanger both sides under clean state by data sampling；

Part II: by the data acquisition to one cycle of operation of recycled water heat exchanger, draws dirtiness resistance Rising characteristic curve, set up dirtiness resistance increase mathematical model；

Part III: utilize the dirtiness resistance growth curve and mathematical model that the previous cycle obtained to next week Phase carries out fouling growth early warning, and carries out online updating；

Wherein: described Part I, specifically follow these steps to carry out:

(1) in two side liquids of recycled water heat exchanger, arrange temperature, flow velocity harvester, gather required temperature Degree, flow parameters；

(2) heat transfer Correlation equations in recycled water side isWherein A_r、m_rIt is respectively Treat criterion equation coefficient and the reynolds number Re of matching_rIndex, according to surveyed data simulate recycled water side pass Hot criteria equation；

(3) heat transfer Correlation equations in intermediary's water side isWherein A_c、m_cIt is respectively Treat criterion equation coefficient and the reynolds number Re of matching_cIndex, according to surveyed data simulate intermediary's water side pass Hot criteria equation；

Described Part II, specifically follows these steps to carry out:

(1) by data acquisition unit, heat collecting exchanger recycled water side is into and out of temperature, in heat collecting exchanger Jie's water side is into and out of temperature, heat collecting exchanger recycled water effluent speed, heat collecting exchanger intermediary water effluent speed；

(2) Nu of recycled water side is calculated respectively by the temperature collected, flow speed data_rWith intermediary's water side Nu_c；

(3) by Nu_r=h_rd_e/ λ calculates recycled water side convection transfer rate h under clean state_r, by Nu_c=h_cd_e/ λ calculates intermediary's water side convection transfer rate h under clean state_c；

(4) byCalculate dirtiness resistance R_f, wherein K is that recycled water heat exchanger is total Heat transfer coefficient, R_WFor recycled water heat exchanger wall thermal conduction resistance；

(5) dirtiness resistance value R corresponding to θ each time of running is recorded_f ^*=R_f；

(6) described recycled water heat exchanger dirtiness resistance R is drawn_f ^*Rising characteristic curve；

(7) described recycled water heat exchanger dirtiness resistance model of growth is set up；

Described Part III, specifically follows these steps to carry out:

(1) utilize the recycled water heat exchanger dirtiness resistance model of growth set up, calculate the heat exchanger in next cycle Dirtiness resistance early warning value R_f ^*；

(2) dirtiness resistance early warning value R is checked_f ^*With dirtiness resistance alarming value R_fmaxRelation, if:

R_f ^*≥R_fmaxCarry out dirt warning or directly initiate apparatus for eliminating sludge；If:

R_f ^*＜ R_fmaxThe most do not carry out dirt warning or stop scale removal；

(3) by data acquisition unit, heat collecting exchanger recycled water side is into and out of temperature, in heat collecting exchanger Jie's water side is into and out of temperature, heat collecting exchanger recycled water effluent speed, heat collecting exchanger intermediary water effluent speed；

(4) Nu of recycled water side is calculated respectively by the temperature collected, flow speed data_rWith intermediary's water side Nu_c；

(5) by Nu_r=h_rd_e/ λ calculates recycled water side convection transfer rate h under clean state_r, by Nu_c=h_cd_e/ λ calculates intermediary's water side convection transfer rate h under clean state_c；

(6) byCalculate dirtiness resistance R_f, wherein K is that recycled water heat exchanger is total Heat transfer coefficient, R_WFor recycled water heat exchanger wall thermal conduction resistance；

(7) dirtiness resistance value R corresponding to θ each time of running is recorded_f ^*=R_f；

(8) described recycled water heat exchanger dirtiness resistance R is drawn_f ^*Rising characteristic curve；

(9) described recycled water heat exchanger dirtiness resistance model of growth is revised, using revised model as next The Early-warning Model of cycle of operation.