CN104048714A - Method for calculating and forecasting gas consumption of positive-displacement compressor group - Google Patents

Abstract

The invention belongs to the field of energy saving of a pneumatic system and implements a method for calculating and forecasting gas consumption of an industrial compressor group. The system consists of compressors, a gas storage tank and a gas appliance. After the system stably operates, firstly, variation delta p1 of a pressure in the gas storage tank in time delta t1 is measured; a gas production rate of the compressors is changed, and a variation quantity is a set value delta Gin; then variation delta p2 of the pressure in the gas storage tank in time delta t2 is measured, variation rates of the pressures in the gas storage tank before and after the gas production rate of the compressors is changed are compared; the volume of the integral system is estimated; then according to the gas production rate Gin of the compressors before variation and the set value delta Gin of the variation quantity, the gas consumption of the system can be estimated.

Description

A kind of calculating and Forecasting Methodology of positive displacement compressor group gas consumption

The invention belongs to energy-saving field of pneumatic, relate to a kind of evaluation method of compressed air system gas consumption.

Background technology

Generally in pressurized gas system, the total gas consumption of system slowly changes in time, for guaranteeing enough instantaneous gas consumptions, when system constructing, the total gas production of compressor has certain having more than needed, when instantaneous gas consumption reaches peak value, gas production rate and gas consumption maintain an equal level, and now system pressure is in minimum, and the operational efficiency of compressor is high; But when the gas consumption of system diminishes, the gas production rate of system is higher than gas consumption, and now system pressure increases, and the operational efficiency of compressor reduces greatly, and whole system is operated under higher power consumption.

For making energy saving of system operation, meeting under the prerequisite that remains on system minimum essential requirement pressure under system works pressure condition, the gas production rate of compressor should maintain an equal level with the gas consumption in system as far as possible, just can make system pressure maintain a lower value, and the gas consumption of system is to change along with the variation of operating mode, for the gas production rate of compressor is mated with the gas consumption of system, first to know the gas consumption of system, as can be seen here, flowmeter be not installed and cannot flowmeter be installed and cannot tests in the system of gas consumption, the gas consumption of estimating system is necessary.

Summary of the invention

The object of the invention is: calculating and Forecasting Methodology that a kind of compressor group gas consumption is provided.

Technical scheme of the present invention is:

When system run to reach stable after, now total gas consumption of system is G _out, it is G that compressor a opens gas production rate _in, differential is done in the Ideal-Gas Equation both sides, ignore temperature variation and obtain:

$G_{\mathrm{out}}=G_{\mathrm{in}}-\frac{V}{\mathrm{RT}}\frac{\mathrm{\Δ}{p}_1}{\mathrm{\Δ}{t}_1}---\left(1\right)$

Wherein: V is the volume of whole system, R is air constant, T air themperature.

Then open valve 3, it is Δ G that compressor b opens gas production rate _in, total gas consumption of supposing the system changes slowly, at Δ t ₂inside ignore it and change, obtain:

$G_{\mathrm{out}}=\mathrm{\Δ}{G}_{\mathrm{in}}+G_{\mathrm{in}}-\frac{V}{\mathrm{RT}}\frac{\mathrm{\Δ}{p}_2}{\mathrm{\Δ}{t}_2}---\left(2\right)$

Simultaneous (1) (2), the volume V that disappears, obtains:

$G_{\mathrm{out}}=G_{\mathrm{in}}-\frac{\mathrm{\Δ}{G}_{\mathrm{in}}}{\frac{\mathrm{\Δ}{p}_2/\mathrm{\Δ}{t}_2}{\mathrm{\Δ}{p}_1/\mathrm{\Δ}{t}_1}-1}$

Advantage of the present invention is: in the compressed air system of flowmeter not being installed or flowmeter cannot be installed, and total gas consumption of estimating system.

Accompanying drawing explanation

Fig. 1 is the inventive method typical case application schematic diagram.

Wherein: 1, compressor a, 2, compressor b, 3, valve, 4, pressure transducer

Embodiment

Below the present invention is further illustrated.

Measuring process is as follows:

(a) open compressor a, and use gas unit, waiting system is stable, Measuring Time Δ t ₁the changes delta p of pressure in interior gas-holder ₁;

(b) open valve 3, open compressor b, the variable quantity of gas production rate is setting value Δ G _in, Measuring Time Δ t then ₂the changes delta p of pressure in interior gas-holder ₂.

Claims (1)

1. the calculating of positive displacement compressor group gas consumption and a Forecasting Methodology, is characterized in that: Measuring Time Δ t first ₁the changes delta p of pressure in interior gas-holder ₁, the gas production rate of change compressor, variable quantity is setting value Δ G _in, Measuring Time Δ t then ₂the changes delta p of pressure in interior gas-holder ₂, the volume of system equals: , wherein, T is gas-holder compressed air temperature; The gas consumption of system equals: $G_{\mathrm{out}}=G_{\mathrm{in}}-\frac{\mathrm{\Δ}{G}_{\mathrm{in}}}{\frac{\mathrm{\Δ}{p}_2/\mathrm{\Δ}{t}_2}{\mathrm{\Δ}{p}_1/\mathrm{\Δ}{t}_1}-1}.$