CN101493353B

CN101493353B - Strong corrosivity medium phase interface measurement method

Info

Publication number: CN101493353B
Application number: CN200910078574XA
Authority: CN
Inventors: 谭梅芳; 曾本忠; 许鸿禧; 张金刚; 余道腾; 柏荣
Original assignee: Zhonghao Chenguang Research Institute of Chemical Industry Co Ltd
Current assignee: Zhonghao Chenguang Research Institute of Chemical Industry Co Ltd
Priority date: 2009-02-26
Filing date: 2009-02-26
Publication date: 2010-09-01
Anticipated expiration: 2029-02-26
Also published as: CN101493353A

Abstract

The invention relates to a phase interface measuring method. The method comprises the following steps: pressure liquid is pressed into a phase to be measured from an upper pressure opening and a lower pressure opening at the same flow, pressure of the pressure openings is measured, and phase interface height h (h=(deltaP-rho1*g*H)/(rho2-rho1)/g) is computed according to pressure difference deltaP between the upper pressure opening and the lower pressure opening, the height H of the upper pressure opening as well as upper phase density rho1 and lower phase density rho2 of two phases in the phase to be measured. In the measuring method, a common instrument can measure the phase interface height of highly corrosive media, which has the advantages of low cost, simple measuring method and wide application; and the measuring method can be used for measuring liquid level, the phase interface height between media with similar density and each phase interface height of a multi-phase mixture besides being especially suitable for measuring the phase interface height of the highly corrosive media.

Description

The measuring method of strong corrosivity medium phase interface

Technical field

The present invention relates to a kind of phase interface measuring method, particularly relate to a kind of phase interface measuring method of strong corrosive media.

Background technology

In chemical reaction, inevitably exist the detachment process of two-phase or multiphase medium in the system, realize continuous, long-term, the normal operation of chemical process, can judge the height of phase interface in the equipment directly, accurately, particularly just seeming at the phase interface height that has strong corrosive media to exist is even more important.

But, in the strong corrosive media environment, in media environments such as hydrofluorite, hydrochloric acid, as instrument using such as magnetic levitation type liquid level meter, differential pressure type level gauges etc. are measured the phase interface position, will soon be corroded, and are difficult to guarantee effectively to use for a long time; If adopt indirect type liquid level gauge measurements such as radar, the cost of instrument is very high again; In addition, need separate multiphase mixture simultaneously, also need to measure the instrument or the method for multi phase interface as production run, therefore, the purpose of this invention is to provide a kind of with low costly, can measure a plurality of phase interfacies simultaneously, and be specially adapted to the method for strong corrosivity medium phase interface.

Summary of the invention

The purpose of this invention is to provide a kind of method of measuring the phase interface of strong corrosive media.

Principle of the present invention is: according to the density of two-phase in impulse mouth (the distributing up and down) pressure differential that records, the distance between the impulse mouth and the testing liquid of testing liquid, calculate the height of phase interface, that is:

Suppose that the relative height of impulse mouth is H up and down, the pressure reduction of two impulse mouths is Δ P, and the density of phase interface upper strata phase is ρ 1, and the density of lower floor's phase is ρ 2,

Δ P=ρ 1 * g * (H-h)+ρ 2 * g * h then

Phase interface height h=(Δ P-ρ 1 * g * H)/(ρ 2-ρ 1)/g

Promptly calculate phase interface height h by above formula.

Phase interface height described in the present invention is the relative height of phase interface, promptly from following impulse mouth to the height of phase interface, as need the absolute altitude of phase interface, only the height addition of relative height of the present invention with following impulse mouth can need be obtained.

Specifically, the present invention selects a kind of liquid as impulse liquid earlier, for avoiding introducing impurity, generally can select for use medium in certain phase, medium or the non-contaminated equipment in the equipment, with a liquid that separates mutually to be measured as impulse liquid; At the equipment side wall opening, draw two impulse mouths up and down, the impulse mouth always is positioned at the both sides of phase interface to be measured about guaranteeing, and upward the impulse mouth is connected with lower floor with the upper strata of phase interface to be measured respectively mutually with following impulse mouth; With forcing pump impulse liquid is pumped into certain flow from the impulse mouth; Measure the pressure of impulse mouth up and down with tensimeter, and calculate the pressure differential of impulse mouth, utilize above-mentioned formula to calculate the height of phase interface.

Method of the present invention can easily be generalized to the measurement of heterogeneous phase interface, as in the measurement of three-phase phase interface, the relative height of supposing last impulse mouth and middle impulse mouth is H1, pressure reduction is Δ P1, and the relative height of middle impulse mouth and following impulse mouth is H2, and pressure reduction is Δ P, the density of three-phase is respectively ρ 1 from top to bottom, ρ 2 and ρ 3, the relative phase interface height h1 of the middle level phase height of impulse mouth (relatively in) then, the relative phase interface height h2 (descending the height of impulse mouth relatively) of lower floor's phase is respectively:

h1＝(ΔP-ρ1×g×H1)/(ρ2-ρ1)/g

h2＝(ΔP-ρ2×g×H2)/(ρ3-ρ2)/g

And the like, can calculate the relative height of heterogeneous phase interface easily, also can calculate the absolute altitude of required phase interface thus easily.

The present invention also can directly utilize differential pressure transmitter to measure the pressure differential of each impulse mouth, and pressure differential is converted into digital signal, be sent to data processing equipment by data line, and according to predefined impulse mouth distance H in the data processing equipment, phase interface upper strata density is ρ 1, lower floor's density is ρ 2, calculates phase interface height h by data processing equipment according to above-mentioned formula.

Owing to as long as guarantee that impulse mouth place is a pressure-fired, just can prevent that the severe corrosive material refluence in the equipment from causing corrosion to instrument, therefore select for use common instrument just can reach the purpose of measurement.

For accurately measuring the height of phase interface, flow with flowmeter control impulse liquid, the flow of impulse mouth is identical about making, as long as guarantee that impulse mouth place is that pressure-fired (comparing with the equipment internal pressure) just can be pressed into impulse liquid in the equipment from the impulse mouth with very little flow.

If need to measure each phase interface height of a plurality of phases in the same equipment, then need to be provided with a plurality of impulse mouths, guarantee each impulse mouth and being connected of needing to measure, and impulse liquid of the same race is pressed in the equipment with identical flow with forcing pump, measure the pressure of each impulse mouth, height and each density mutually by each known impulse mouth utilize above-mentioned formula to calculate the height of each required phase interface.

Technical scheme of the present invention has following advantage:

1. the present invention adopts general instrument just can measure the phase interface height of strong corrosive media, and with low cost, measuring method is simple.

Impulse liquid select for use do not bring into impurity and segregative other liquid or with equipment in the identical liquid of a kind of material, utilize this measuring method can be in separating mutually introducing impurity.

3. method of the present invention is widely used, and except being specially adapted to measure the phase interface height of strong corrosive media, also can be used for measuring liquid level, the phase interface height between the close medium of density measurement and measure each phase interface height of multiphase mixture.

Description of drawings

The synoptic diagram of Fig. 1 phase interface measuring method, wherein, FV is the control gear of pneumatic valve; FC is a pneumatic valve; Pd is a differential pressure transmitter; LICA is the relative phase interface height that calculates; FI is that flow shows; FT and FE are the associating topworks of Control Flow; FICQ is flow control; H is the relative height of two impulse mouths; H is the phase interface height.

Embodiment

Following examples are used to illustrate the present invention, but are not used for limiting the scope of the invention.

The mensuration of embodiment 1 two-phase phase interface

Method of the present invention is used to measure upper strata phase aqueous hydrofluoric acid, and lower floor is the phase interface of freon mutually.

Utilize water as impulse liquid, open the impulse mouth at the equipment sidewall, last impulse mouth and upper strata inorganic mixture strong acid connection mutually, following impulse mouth is communicated with organic mixture, and the relative height of impulse mouth is H up and down; Guarantee that impulse liquid is with certain flow (just needing to give the pressurization of impulse liquid with force (forcing) pump if the pressure of impulse liquid is lower than the equipment internal pressure) (guarantee impulse mouth pressure-fired just can) from impulse mouth inflow equipment up and down, for guaranteeing and can measuring the impulse flow quantity, flowmeter is installed, the pressure transducer of differential pressure transmitter is separately positioned on impulse mouth and following impulse mouth, and the differential pressure that records Δ P as a result is sent to computing machine by data line.

As shown in Figure 1, the mixture A of aqueous hydrofluoric acid and freon is with in certain flow feeding equipment, with water as material B also with in the certain flow inflow equipment, simultaneously material B also as impulse liquid by in the impulse mouth access arrangement, make the flow of impulse mouth up and down identical with valve control; Two pressure probes of differential pressure transmitter are separately positioned on impulse mouth up and down, and the pressure difference data Δ P that obtains is delivered to computing machine, are gone out the height h of phase interface by COMPUTER CALCULATION.

The relative height H of default upper and lower impulse mouth in the computing machine, the value of the density p 1 of upper strata phase and the phase density ρ of lower floor 2, according to following formula:

h＝(ΔP-ρ1×g×H)/(ρ2-ρ1)。

Calculate the height h of phase interface.

As shown in Figure 1, can also make phase interface keep stable, be convenient to separation of material 1 and 2, realize that promptly aqueous hydrofluoric acid and the stable of freon separate by the mensuration of phase interface.Be the inflow equipment that guarantees that material can continous-stable, pneumatic valve control (as figure FV) is installed on material conveying pipe, and it is chain with the differential pressure transmitter of impulse liquid, can control the addition of material like this according to the phase interface height that calculates by the detected pressure reduction of differential pressure transmitter (as figure h), realization is to the control of the continous-stable of phase interface, and then the operation of realization chemical process continous-stable.

The mensuration of embodiment 2 three-phase phase interfacies

It is hydrogen cyanide that method of the present invention is used to measure the upper strata, and the middle level is a difluorochloromethane, and lower floor is CCl ₄Phase interface, utilize with easily with the media of the interior various feed separation of equipment: water is opened the impulse mouth as impulse liquid at the equipment sidewall, and last impulse mouth is connected with hydrogen cyanide, and middle impulse mouth is communicated with difluorochloromethane, following impulse mouth and CCl ₄Be communicated with, go up, the relative height between the middle impulse mouth is H1, in, the relative height of impulse mouth is H2 down; Guarantee that impulse liquid flows into equipment with identical flow from upper, middle and lower impulse mouth, the pressure transducer of differential pressure transmitter 2 is separately positioned on middle impulse mouth and following impulse mouth, the pressure transducer of differential pressure transmitter 1 is separately positioned on impulse mouth and following impulse mouth, and the differential pressure that records Δ P2 and Δ P1 as a result is sent to computing machine by data line.

The default relative height H1 that goes up impulse mouth and middle impulse mouth in the computing machine, the relative height H2 of middle impulse mouth and following impulse mouth, the density p 1 of upper strata phase, the concrete value of middle level phase density ρ 2 and the phase density ρ of lower floor 3, according to following formula:

h1＝(ΔP-ρ1×g×H1)/(ρ2-ρ1)/g；

h2＝(ΔP-ρ2×g×H2)/(ρ3-ρ2)/g；

Calculate the relative height h2 (descending the impulse mouth relatively) and middle level phase interface relative height h1 (impulse mouth in relative) of lower floor's phase interface.

Claims

1. method of measuring phase interface, be that impulse liquid is pressed into phase to be measured with same traffic from each impulse mouth, and the pressure of mensuration impulse mouth, according to the relative height H of the pressure differential Δ P of impulse mouth, impulse mouth and the phase to be measured density p 1 and the phase density ρ of lower floor 2 of phase at the middle and upper levels, calculate the height h of phase interface:

h＝(ΔP-ρ1×g×H)/(ρ2-ρ1)

Wherein, described impulse liquid being pressed into phase to be measured with same traffic from the impulse mouth, is that impulse liquid is pressurizeed by forcing pump, by the flowmeter Control Flow, enters and to be measuredly realizes mutually.

2. the method for claim 1 is characterized in that, described impulse liquid is one or more in phase to be measured or the phase medium to be measured, or with mutually segregative liquid to be measured.

3. the method for claim 1 is characterized in that, described impulse mouth is positioned at the both sides of phase interface to be measured, and with respectively being connected of phase interface to be measured.

4. the method for claim 1 is characterized in that, the pressure of described impulse mouth is measured by tensimeter.

5. the method for claim 1, it is characterized in that, be to utilize differential pressure transmitter to measure the pressure differential of each impulse mouth, and pressure differential is converted into digital signal, be sent to data processing equipment by data line, and according to predefined impulse mouth distance H in the data processing equipment, phase interface upper strata phase density ρ 1, the phase density ρ of lower floor 2 calculates phase interface height h by data processing equipment formula according to claim 1.