CN103150676A - Energy consumption estimation method for industrial circulating water supply pump station - Google Patents

Abstract

The invention discloses an energy consumption estimation method for an industrial circulating water supply pump station. The method comprises the following steps of: firstly, fitting from an external characteristic curve of a pump to obtain a flow-power equation and a flow-lift equation of the pump; and secondly, obtaining a device demand equation by a system engineering drawing and obtaining minimum water outlet pressure, i.e., water outlet pressure of the pump after frequency conversion, of the pump required by the system in combination with recording of working condition points (pump outlet pressure and input current and voltage of a matched motor). The water outlet pressure of the pump before frequency conversion is obtained through the flow-lift equation and a similar parabolic equation of the pump. The similarity ratio of each working condition point is calculated in combination with water outlet pressure of the pump before and after the frequency conversion, and further, the flow-power equation after variable frequency speed control is obtained. The space is saved through comparison of flow-power curves before and after the variable frequency speed control.

Description

A kind of industrial circulating water water supply pumping plant energy consumption evaluation method

Affiliated technical field

The present invention relates to the pump energy consumption evaluation areas, especially can need not flowmeter, need not pipeline is done the method for in the situation of any transformation, water pump being carried out energy consumption assessment.

Background technology

Circulation is the lifeline of explained hereafter, is widely used in the industries such as oil, chemical industry, iron and steel, metallurgy, electric power.In actual use,, supply channel improper due to the pump type selecting designs the factors such as unreasonable, and running efficiency of system is lower, the energy dissipation phenomenon is serious.

And the survey instrument that at present needs specialty for the energy consumption evaluation method of circulating water system water supply pumping plant as flowmeter, pressure instrumentation and relevant measurement of power instrument more.This can satisfy for large enterprise substantially, but for the vast middle-size and small-size industrial enterprise of China, lacks equipment and the personnel of specialty, can't carry out energy consumption assessment to circulation, and then rectify and improve.

Summary of the invention

The invention provides a kind of recirculated water water supply pumping plant energy consumption evaluation method that need not professional surveying instrument, present domestic medium and small sized enterprises ubiquitous circulation energy audit program lacks to solve, the present situation of energy consumption assessment difficulty.

Technical scheme of the present invention is:

Pump discharge and pipe network representative point (being generally the water supply peak) are equipped with tensimeter, and the relative dimensions of supply water height and circulation all can measure or recognize information accurately from manufacturer.The dynamic characteristic of the basic parameter of make-up pump, external characteristic curve and necessary electromotor all has in instructions when producer buys this equipment.

Summary according to actual conditions, do not adopt the surveying instrument of specialty, but can obtain following measuring amount: pump necessary electromotor input voltage, electric current, pump discharge, pipe network representative point tensimeter registration, the circulation interrelated geometrical parameters, the pump external characteristic curve, pump necessary electromotor dynamic characteristic, pump basic parameter.

Based on above-mentioned data information, as shown in Figure 1, process according to the following steps:

Step 1: the P-Q equation, the H-Q equation that are obtained pump by the pump external characteristic curve

Step 2: obtain each operating point flow in conjunction with each operating point pump discharge measuring point tensimeter registration and H-Q equation

Step 3: by each operating point flow and device demand equation, obtain the required minimum pressure of system under each operating mode

Step 4: the ratio of similitude that obtains the pump under each operating mode in conjunction with the similar parabolic equation of pump

Step 5: obtain flow powertrace after frequency conversion by the ratio of similitude under each operating mode

Step 6: before and after the contrast frequency conversion, the flow powertrace can be found out the energy saving space

The invention has the beneficial effects as follows: need not the survey instrument of specialty, need not pipeline is done any change, can carry out energy consumption assessment to a circulating water system water supply pumping plant.Evaluation process is simple and convenient, reliable results.

Description of drawings

The present invention is further described below in conjunction with drawings and Examples

Fig. 1 is the energy consumption assessment process flow diagram

Fig. 2 is * * factory circulation sketch

Fig. 3 is the external characteristic curve of make-up pump

Fig. 4 is the necessary electromotor dynamic characteristic

Fig. 5 is flow powertrace before and after frequency control

Embodiment

Table 1 is the basic parameter of make-up pump in pilot plant's circulation:

Table 1 make-up pump basic parameter

Step 1: can be obtained by the match of Fig. 3 pump external characteristic curve

The H-Q curvilinear equation:

H＝-7×10 ^-7Q ³+7×10 ^-5Q ²-0.0105Q+36.078 (1)

The H-P curvilinear equation:

P＝-1.278×10 ^-6Q ³+0.0005Q ²+0.0111Q+10.413 (2)

Step 2: obtain 13 operating point flows in conjunction with each operating point pump discharge measuring point tensimeter registration and H-Q equation

Fig. 2 is * * factory circulation sketch, can be got to measuring point place row Bernoulli equation by pump discharge:

$H={679.7Q}^2+\frac{P_s}{9800}+2.2---\left(3\right)$

P in formula _sBe delivery side of pump measuring point pressure.

Get P by formula (1), (3) _sWith the pass of Q be:

P _S＝-7×10 ^-7Q ³+1.7554×10 ^-5Q ²-0.0105Q+33.878 (4)

In the circulation one-period, on average choose monitoring point P _sLocate 13 force value, as shown in table 2, obtain corresponding operating point flow according to formula (4).

The data of table 2 collection in worksite

Step 3: by each operating point flow and device demand equation, obtain the required minimum pressure of system under each operating mode

In Fig. 2, the water supply peak is 15m, delivery side of pump pressure tap height is 2m, process requirements pressure is minimum is 20kPa, considers the inertia of control system, for guaranteeing production safety and stable, process requirements pressure is improved 5kPa, make it constant in 25kPa, to getting the relation of circulation ductwork pressure and flow to water supply peak place row Bernoulli equation, namely install party in request's journey by the water cooling pond water surface:

H′＝20.55+1230(Q/3600) ² (5)

Can be got under 13 operating points the minimum pressure that the circulation pipe network is required, i.e. pump lift after frequency conversion by formula (5).

Step 4: the ratio of similitude that obtains the pump under each operating mode in conjunction with the similar parabolic equation of pump

The similar parabolic equation of pump is:

H＝λQ ² (6)

According to formula (5), (6), make H=H ', substitution Q ₁, Q ₂Q ₁₃Obtain the equation coefficient lambda under 13 operating modes of surveying ₁, λ ₂λ ₁₃, in the system of equations with this coefficient substitution formula (1), (6) composition:

$\left\{\begin{array}{c}H=-7\×{10}^{-7}{Q}^3+7\×{10}^{-5}{Q}^2-0.0105Q+36.0078\\ H=\mathrm{\λ}{Q}^2,\mathrm{\λ}={\mathrm{\λ}}_1{\mathrm{\λ}}_2......{\mathrm{\λ}}_{13}\end{array}\right.---\left(7\right)$

Simultaneous formula (2), (7) obtain the front consumed power of 13 operating point frequency conversions and flow lift, based on lift of pump H ' after frequency conversion, obtain the ratio of similitude k of pump ₁, k ₂... k ₁₃

Step 5: obtain flow powertrace after frequency conversion by the ratio of similitude under each operating mode

Obtain the power consumption P ' under the actual demand operating mode after speed governing according to the scaling law of pump:

$P_x^{\′}=k_x^{3}P---\left(9\right)$

Draw pump discharge power relation under converting operation by formula (2), (9):

P＝8.285×10 ^-8Q ³+1.768×10 ^-4Q ²+0.02719Q+3.893 (10)

Step 6: before and after the contrast frequency conversion, the flow powertrace can be found out the energy saving space

By Fig. 5, the H-Q curve under contrast pump power frequency and frequency conversion can be found out: flow is less than 220m ³During/h, the energy saving space higher than the annual flow of 20% this pump less than 210m ³/ h is therefore its energy saving space is higher than 20%.In fact, power demand whole year of this pump is below 25kW, and is as shown in table 3, supporting 37kW motor, the serious waste energy.

Table 3 pump year service data

Claims (3)

1. a novel industrial circulating water system water supply pumping plant energy consumption evaluation method, is characterized in that: based on chemical engineering process key point data, pump hydraulic performance curve and motor load performance curve, take frequency control as power-economizing method.

2. a kind of industrial circulating water system energy consumption evaluation method as described in right 1 is characterized in that: the flow that need not to measure make-up pump can be put down and be measured the energy saving space.

3. a kind of industrial circulating water system energy consumption evaluation method as described in right 1, is characterized in that: need not circulation is done any change, need not the valuable measurement basis of specialty, can complete assessment.

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