CN102323304B - Ceramic dielectric sensor and preparation method thereof used for detecting relative volume concentration of methanol gasoline - Google Patents

Abstract

The invention discloses a ceramic dielectric sensor and a preparation method thereof used for detecting the relative volume concentration of methanol gasoline. The ceramic dielectric sensor comprises a tubular casing, ceramic dielectric tubular outer-ring electrodes arranged on two end covers inside the casing, and an inner-core electrode with holes in the rod-shaped center, wherein a ceramic dielectric material is composed of rutile-structured TiO2 and Mg2TiO4 according to a mass ratio. The preparation method of the ceramic dielectric sensor comprises the steps of: preparing the rutile-structured TiO2 and the Mg2TiO4; mixing the TiO2 and the Mg2TiO4, pressure-forming, static-pressure blank-forming and sintering into ceramic dielectric; coating an electrode paste on the ceramic dielectric, and sintering into a tubular or rod-shaped ceramic dielectric electrode; and arranging the ceramic dielectric electrode in the tubular casing to constitute the ceramic dielectric sensor. The ceramic dielectric sensor and the preparation method, disclosed by the invention, have the advantages of high sensitiveness, quick response and recovery time, good stability, reliable use and low preparation cost.

Description

Detect ceramic dielectric sensor and the preparation method of methanol gasoline relative volume concentration

Technical field

The present invention relates to a kind of ceramic dielectric sensor and preparation method who detects methanol gasoline relative volume concentration, belong to sensor technical field.

Background technology

Along with the development of society, on the one hand China's present stage automobile pollution continues to increase, and on the other hand, world petroleum resource also is faced with increasingly severe situation, like this with regard to so that the imbalance between supply and demand of China's fuel oil increasingly sharpen.2010, China's external oil dependency degree was near 55%.Seek a kind of effectively resource of petroleum replacing, satisfy energy demand and the strategic demand of China's economic construction, become one of China's difficult problem in the urgent need to address.For the special national conditions of the oil-poor weak breath of the many coals of China and the current situation of correlation technique, implement energy diversification strategy, can become practicable a kind of effective way of China's present stage.

Methyl alcohol is as one of substitute of gasoline, be that raw material is made by coal or rock gas, have that discharging is low, octane value is high, anti-knock properties good, resource is relatively abundant, the advantages such as cost is low, convenient transportation, because of a little, increasingly extensive by the formulated use of methanol gasoline in automobile of cosolvent with a certain proportion of methyl alcohol and gasoline.But the quality of methyl alcohol is low, and calorific value is also low than gasoline, and is also not identical with the demand to oxygen in the combustion process that do not coexist of methanol content, how methanol content in this fuel blend carried out real-time monitoring, and mate different air-fuel ratios, becomes a new problem.In differentiating the content and the method for ratio of methyl alcohol in gasoline, mainly contain specific inductive capacity, spectrophotometer method, SAW (Surface Acoustic Wave) device (SAW) method, anaclasis method and component analyzing method etc., but these methods exist detection means complicated, are not suitable for the problems such as online detection.

In recent years, along with going deep into of research, people use new material, new technology has been researched and developed many new sensors.At present, the various kinds of sensors of ceramic based material becomes the focus that people pay close attention to just gradually, and the extremely people's favor of the dielectric properties that it is excellent and reliable and stable physicochemical property is widely used in a lot of fields.

Summary of the invention

The object of the invention is to provide a kind of ceramic dielectric sensor and preparation method who detects methanol gasoline relative volume concentration, and this sensor can accurately detect methanol gasoline relative volume concentration, and its preparation method is simple.

The present invention is realized by the following technical programs, a kind of ceramic dielectric sensor that detects methanol gasoline relative volume concentration, this sensor comprises tubular shell, it is characterized in that, in tubular shell, in two end cap the porose interior core electrode of ceramic dielectric tubulose outer ring electrode and the bar-shaped center of ceramic dielectric is set, the methanol gasoline runner also is set on the end cap at tubular shell two ends, the cross section that forms between runner on the two end cap and two electrodes is the runner UNICOM of annular, and described ceramic medium material is the TiO by rutile structure ₂And Mg ₂TiO ₄In mass ratio (0.8～0.2): (0.2～0.8) forms.

The ceramic dielectric sensor preparation method of above-mentioned detection methanol gasoline relative volume concentration is characterized in that comprising following process:

1) with the TiO that purchases ₂Powder is by adding bowl mill, and abundant wet-milling 20～22h take water as abrasive media 100～120 ℃ of temperature fully after the oven dry, inserts in the sintering furnace routinely sintering schedule in temperature 1000-1200 ℃ of calcining 2h, the TiO of titania structure ₂TiO with synthetic rutile structure ₂After magnesium carbonate is 1: 2 mixing by the mol ratio of titanium and magnesium, take water as medium behind abundant wet-milling 10～12h, at 100～120 ℃ of bone dries of temperature, insert in the sintering furnace routinely sintering schedule in 1150-1250 ℃ of calcining 2h, with synthetic Mg ₂TiO ₄Material;

2) with step 1) system TiO ₂And Mg ₂TiO ₄In mass ratio (0.8～0.2): mix (0.2～0.8), after mixing rear powder ball milling 10～12h, at 100～120 ℃ of bone dries of temperature, dry-pressing take pressure as 10MPa becomes tubulose and bar-shaped, again to wait static pressure 200MPa to be pressed into tubulose and bar-shaped ceramic blank, ceramic blank is pressed the electronic ceramics common process in 1200 ℃ of-1380 ℃ of sintering of temperature in sintering furnace, form ceramic dielectric;

3) with step 2) electrode slurry of the ceramic medium material working surface metallizing silver that sinters, in sintering furnace, in 850 ℃ of lower burning infiltrations of temperature, form tubulose and bar-shaped ceramic dielectric electrode;

4) with step 3) system tubulose and bar-shaped ceramic dielectric electrode, respectively as outer ring electrode and interior core electrode, they are packed in the housing of tubulose, and wire is drawn in connection, the methanol gasoline runner is set on the end cap at tubular shell two ends, the cross section that forms between runner on the two end cap and two electrodes is the runner UNICOM of annular, thereby makes the ceramic dielectric sensor that detects methanol gasoline relative volume concentration.

With ceramic dielectric sensor above-mentioned or the said method preparation, the theoretical foundation that detects methanol gasoline relative volume concentration is:

According to coaxial columnar capacitor calculation of capacity formula, establish the ceramic dielectric electric capacity electric capacity corresponding with tested methanol gasoline, be respectively C ₁, C ₂, then have:

$C_1=\frac{2\mathrm{\π}{\mathrm{\ϵ}}_c{\mathrm{\ϵ}}_{0}l}{\ln \frac{r_2}{r_1}}$

${\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="HSA00000517245300011.png"\; state="\{\{state\}\}">C</figure-callout>}}_2=\frac{2\mathrm{\&pi;}{\mathrm{\&epsiv;}}_b{\mathrm{\&epsiv;}}_{0}l}{\ln \frac{r_3}{{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="HSA00000517245300011.png"\; state="\{\{state\}\}">r</figure-callout>}}_2}}$

In the formula: r1 is the radius of inner core electrode ceramic medium endoporus; R2 is the radius of inner core electrode ceramic medium; R3 is the radius of outer ring electrode inside surface; L is the total length of sensor; ε c is the relative dielectric constant of ceramic medium material, and ε b is the relative dielectric constant of fluid to be measured, and ε o is permittivity of vacuum.

Sensor total capacitance C can be considered C ₁With C ₂Series connection, its expression formula is:

$C=\frac{C_1{C}_2}{C_1+{\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="HSA00000517245300011.png"\; state="\{\{state\}\}">C</figure-callout>}}_2}=\frac{2\mathrm{\&pi;}{\mathrm{\&epsiv;}}_b{\mathrm{\&epsiv;}}_c{\mathrm{\&epsiv;}}_{0}l}{{\mathrm{\&epsiv;}}_b\ln \frac{r_3}{{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="HSA00000517245300011.png"\; state="\{\{state\}\}">r</figure-callout>}}_2}+{\mathrm{\&epsiv;}}_c\ln \frac{r_2}{r_1}}$

Relevant because containing quantity of methyl alcohol in total capacitance and the methanol gasoline, therefore by formula as can be known, can converse gasoline according to the capacitance that records and contain methyl alcohol relative volume amount.

Adopt ceramic dielectric sensor of the present invention to have fast, good stability of highly sensitive, response-recovery time, the characteristics such as safe and reliable, solved the key technical problem of detection of fuel in the current carbinol gasoline fuel automobile, and detect the propellant composition difference according to sensor, different signals can be provided, thereby different data are complementary with it in the corresponding engine electronic control unit, realize engine washing, efficiently burning, reach the purpose of energy-saving and emission-reduction.Ceramic dielectric sensor of the present invention can use in all kinds of locomotives of methanol gasoline or ethanol petrol, also can be applicable on the doping composition detection of methanol gasoline or ethanol petrol.In addition, this ceramic dielectric sensor also has energy consumption and preparation cost is low, volume is little and characteristics simple to operate.

Description of drawings

Fig. 1 is ceramic dielectric sensor structural representation of the present invention.

Fig. 2 is the left view of Figure 1A-A.

Among the figure: 1 for drawing wire, and 2 is outlet end cap, and 3 is tubular shell, and 4 is the ceramic dielectric outer ring electrode, and 5 is core electrode in the ceramic dielectric, and 6 is the ceramic electrode silver coating, and 7 is inlet end cap, and 8 is the methanol gasoline runner.

Embodiment

Embodiment 1:

1) take by weighing titania 100 gram, add bowl mill, take water behind abrasive media wet-milling 20h, at 100～120 ℃ of bone dries of temperature, cross 200 purposes sieves, afterwards in the air calcination stove routinely sintering schedule in 1000 ℃ of calcining 2h, with the TiO of titania structure ₂Take by weighing titania 80 grams, take by weighing magnesium carbonate 168 grams, add bowl mill, behind abrasive media wet-milling 10h, at 100～120 ℃ of bone dries of temperature, cross 200 purposes sieve take water.Afterwards in the air calcination stove routinely sintering schedule in 1150 ℃ of calcining 2h, with synthetic Mg ₂TiO ₄Material.

2) press 0.8TiO ₂-0.2Mg ₂TiO ₄Material takes by weighing the TiO of rutile synthetic in the front (1) ₂Material 80 grams, Mg ₂TiO ₄Material 20 grams mix forming composite granule, add bowl mill, take water as abrasive media wet-milling 10h, at 120～125 ℃ of bone dries of temperature.Then through dry-pressing formed tubulose and the bar-shaped ceramic blank of being pressed into take pressure as 10MPa, again to wait static pressure 200MPa to be pressed into tubulose and bar-shaped pottery, prepare internal diameter 50mm, wall thickness 4mm, the cylindric ceramic dielectric of long 50mm is the external electrode matrix, and prepare external diameter 15mm, center bore 4mm, long 50mm cylindrical ceramic medium is interior electrode matrix.The ceramic body of forming behind binder removal, is pressed the electronic ceramics common process in 1200 ℃ of sintering under air conditions, form ceramic dielectric.

3) the ceramic medium material working surface that sinters is coated with the electrode slurry that is covered with argent, in 850 ℃ of lower burning infiltrations, forms the ceramic dielectric sensor material.

Two ceramic electrodes that 4) will prepare are fixed on by polyurethane material and form on the outlet end cap of tubular shell, and use the sealant sealing interface, and the tubular shell inlet end cap is connected upper rear enclosed, and simultaneously, two ceramic electrode inside surfaces are drawn respectively wire.Form the sensor of ceramic dielectric.

5) be full of the methanol gasoline liquid that volume content is respectively 90%, 50%, 10% methanol concentration by two mouths of pipe at tubular shell, with LCR multifunctional instrument survey sensor electric capacity, the result of methanol gasoline liquid electric capacity who obtains different methanol concentrations is as shown in table 1.

Embodiment 2:

Step of preparation process is identical with embodiment 1, and difference is: in step 1) in the air calcination stove sintering temperature be 1150 ℃ the calcining 2h, with the TiO of titania structure ₂Sintering temperature is 1200 ℃ of calcining 2h in the air calcination stove, with synthetic Mg ₂TiO ₄Material; In step 2) in get the TiO of rutile structure ₂Material 50g gets Mg ₂TiO ₄Material 50 grams mix forming composite granule; With forming, the identical ceramic body of size and embodiment 1 is behind binder removal, and sintering temperature is 1280 ℃ of sintering under air conditions, form ceramic dielectric; In step 5) in, the test result of variable concentrations methanol gasoline liquid electric capacity is as shown in table 1.

Embodiment 3:

Step of preparation process is identical with embodiment 1, and difference is: in step 1) in the air calcination stove sintering temperature be 1200 ℃ the calcining 2h, with the TiO of titania structure ₂Sintering temperature is 1250 ℃ of calcining 2h in the air calcination stove, with synthetic Mg ₂TiO ₄Material; In step 2) in get the TiO of rutile structure ₂Material 50g gets Mg ₂TiO ₄Material 80 grams mix forming composite granule; With forming, the identical ceramic body of size and embodiment 1 is behind binder removal, and sintering temperature is 1380 ℃ of sintering under air conditions, form ceramic dielectric; In step 5) in, the test result of variable concentrations methanol gasoline liquid electric capacity is as shown in table 1.

Table 1 has been listed and has been adopted the result of ceramic dielectric sensor test different volumes concentration carbinol gasoline fuel of the present invention as follows:

Claims (1)

1. ceramic dielectric sensor preparation method who detects methanol gasoline relative volume concentration, this ceramic dielectric sensor comprises tubular shell, in tubular shell, in two end cap the porose interior core electrode of ceramic dielectric tubulose outer ring electrode and the bar-shaped center of ceramic dielectric is set, the methanol gasoline runner also is set on the end cap at tubular shell two ends, the cross section that forms between runner on the two end cap and two electrodes is the runner UNICOM of annular, and described ceramic medium material is the TiO by rutile structure ₂And Mg ₂TiO ₄In mass ratio (0.8～0.2): (0.2～0.8) forms, and it is characterized in that comprising following process:

1) with the TiO that purchases ₂Powder adds bowl mill, and abundant wet-milling 20～22h take water as abrasive media 100～120 ℃ of temperature fully after the oven dry, inserts in the sintering furnace routinely sintering schedule in temperature 1000-1200 ℃ of calcining 2h, the TiO of titania structure ₂TiO with synthetic rutile structure ₂After magnesium carbonate is 1: 2 mixing by the mol ratio of titanium and magnesium, take water as medium behind abundant wet-milling 10～12h, at 100～120 ℃ of bone dries of temperature, insert in the sintering furnace routinely sintering schedule in 1150-1250 ℃ of calcining 2h, with synthetic Mg ₂TiO ₄Material;

2) with step 1) system TiO ₂And Mg ₂Ti O ₄In mass ratio (0.8～0.2): mix (0.2～0.8), after mixing rear powder ball milling 10～12h, at 100～120 ℃ of bone dries of temperature, dry-pressing take pressure as 10MPa becomes tubulose and bar-shaped, again to wait static pressure 200MPa to be pressed into tubulose and bar-shaped ceramic blank, ceramic blank is pressed the electronic ceramics common process in 1200 ℃ of-1380 ℃ of sintering of temperature in sintering furnace, form ceramic dielectric;

3) with step 2) electrode slurry of the ceramic medium material working surface metallizing silver that sinters, in sintering furnace, in 850 ℃ of lower burning infiltrations of temperature, form tubulose and bar-shaped ceramic dielectric electrode;

4) with step 3) system tubulose and bar-shaped ceramic dielectric electrode, respectively as outer ring electrode and interior core electrode, they are packed in the housing of tubulose, and wire is drawn in connection, the methanol gasoline runner is set on the end cap at tubular shell two ends, the cross section that forms between runner on the two end cap and two electrodes is the runner UNICOM of annular, thereby makes the ceramic dielectric sensor that detects methanol gasoline relative volume concentration.

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