阅读说明：本技术 一种磷酸化的钙钛矿型催化剂及其制备方法和应用 (Phosphorylated perovskite catalyst and preparation method and application thereof ) 是由 翁小乐 曹可锌 孟庆洁 吴忠标 于 2020-12-16 设计创作，主要内容包括：本发明公开了一种磷酸化的钙钛矿型催化剂及其制备方法和应用,制备方法包括以下步骤：(1)将镧锰钙钛矿置于磷酸溶液中进行浸渍,浸渍完成后洗涤、干燥,获得磷酸化的镧锰钙钛矿；(2)将磷酸化的镧锰钙钛矿置于活性成分金属盐的溶液中进行浸渍,浸渍完成后干燥、煅烧、研磨筛分,获得磷酸化的钙钛矿型催化剂。本发明的催化剂制备方法简单,催化剂的催化活性及稳定性较好,在催化降解含氯挥发性有机物的整个反应体系避免了高毒性副产物二噁英的生成温度区间,减少了多氯高毒性副产物如二噁英等的生成,对环境更友好。(The invention discloses a phosphorylated perovskite catalyst and a preparation method and application thereof, wherein the preparation method comprises the following steps: (1) dipping the lanthanum-manganese perovskite in a phosphoric acid solution, and washing and drying after the dipping to obtain phosphorylated lanthanum-manganese perovskite; (2) and (3) placing the phosphorylated lanthanum-manganese perovskite into a solution of an active component metal salt for dipping, and drying, calcining, grinding and screening after dipping to obtain the phosphorylated perovskite catalyst. The catalyst disclosed by the invention is simple in preparation method, good in catalytic activity and stability, capable of avoiding the generation temperature range of a high-toxicity byproduct dioxin in the whole reaction system for catalytically degrading the chlorine-containing volatile organic compound, reducing the generation of polychlorinated high-toxicity byproducts such as dioxin and the like, and more environment-friendly.)

1. A method of preparing a phosphorylated perovskite catalyst, comprising the steps of:

(1) dipping the lanthanum-manganese perovskite in a phosphoric acid solution, and washing and drying after the dipping to obtain phosphorylated lanthanum-manganese perovskite;

(2) and (3) placing the phosphorylated lanthanum-manganese perovskite into a solution of an active component metal salt for dipping, and drying, calcining, grinding and screening after dipping to obtain the phosphorylated perovskite catalyst.

2. The method of preparing a phosphorylated perovskite catalyst of claim 1, wherein the lanthanum manganese perovskite is a layered lanthanum manganese perovskite.

3. The method of preparing a phosphorylated perovskite catalyst according to claim 2, wherein the method of preparing a layered lanthanum manganese perovskite comprises:

(a) mixing a salt solution containing lanthanum and manganese elements with an acid solution to form a sol, drying the sol, and calcining at the temperature of 650-750 ℃ in an air atmosphere for 4-6h to obtain intermediate powder;

(b) and (3) keeping the intermediate powder at the constant temperature of 100-150 ℃ for 10-15h, washing, drying, and calcining at the temperature of 650-750 ℃ in an air atmosphere for 4-6h to obtain the layered lanthanum-manganese perovskite.

4. The method according to claim 1, wherein the amount of phosphorus supported is 0.1 to 5% by mass of the phosphorus element.

5. The method of preparing a phosphorylated perovskite catalyst according to claim 1, wherein the active component metal salt is at least one of soluble salts of gold, platinum, ruthenium and palladium.

6. The method according to claim 1 or 5, wherein the amount of the active component metal supported is 0.3 to 3% by mass of the active component metal element.

7. The method for preparing a phosphorylated perovskite catalyst according to claim 1, wherein in the step (2), the mixture of the phosphorylated lanthanum manganese perovskite and the active ingredient metal salt solution is heated to 30 to 80 ℃ and the pH thereof is adjusted to 7 to 12.

8. A phosphorylated perovskite catalyst produced by the production method according to any one of claims 1 to 7.

9. Use of a phosphorylated perovskite catalyst according to claim 8 for the pyro-hydrolytic degradation of chlorine containing volatile organic compounds, comprising:

reacting flue gas containing chlorine-containing volatile organic compounds and water vapor under the action of the perovskite catalyst;

in the flue gas, the content of water vapor is 1-10 vol%;

the reaction temperature is 150-600 ℃.

10. The use according to claim 9, wherein the flue gas contains 2-6 vol% of water vapor; the reaction temperature is 450-550 ℃.

Technical Field

The invention relates to the technical field of waste gas treatment, in particular to a phosphorylated perovskite catalyst, a preparation method thereof and application thereof in catalytic oxidation of chlorine-containing volatile organic compounds.

Background

chlorine-Containing Volatile Organic Compounds (CVOCs) are mainly derived from industrial waste gases and are increasingly receiving a great deal of attention due to their persistent environmental hazard.

CVOCs are generally derived from the production and use of vinyl chloride, herbicides, plastics, and the like. CVOCs have high biotoxicity and high durability, and some CVOCs (such as dichloromethane and tetrachloroethylene) can destroy the ozone layer and increase global warming, causing serious harm to human health. Industrial emissions of CVOCs have been banned by legislative directives in many countries and therefore need to be dealt with more properly.

The existing CVOCs treatment technology is mainly divided into recovery technology and destruction technology, wherein the former comprises an adsorption method, an absorption method, a condensation method, a membrane separation method and the like, and the latter comprises a biodegradation method, a photocatalysis method, a plasma method, a direct combustion method, a catalytic hydrodeoxygenation method, a catalytic combustion method and the like. The catalytic combustion method is considered to be the most promising treatment method at present by comprehensively considering the multiple factors such as the application range, the cost, the treatment thoroughness and the like of various methods.

The core of the catalytic combustion technology is the development of catalysts, and currently, research mainly focuses on noble metal catalysts, molecular sieve catalysts and transition metal oxide catalysts. The inactivation of the catalyst in the catalytic oxidation process of CVOCs is mainly embodied in two aspects, namely that Cl is easy to react with active components in the catalytic combustion process to generate metal chlorides and oxychlorides with lower boiling points, so that the loss of the active components is caused, and Cl is strongly adsorbed on the catalyst, so that active sites are occupied.

Chinese patent publication No. CN110787797A discloses a catalytic combustion catalyst for chlorine-containing organic waste gas and a preparation method thereof, wherein the catalyst takes composite oxide dodecacalcium heptaluminate as a carrier and PtO₂As noble metalsCenter of sex, PtO₂Accounting for 0.1 to 0.3 percent of the total mass of the catalyst. Wherein, PtO₂The composite oxide dodecacalcium heptaluminate has a unique cage cavity structure, contains a large number of active oxygen ion groups and has good thermal stability, so that the catalyst has extremely high Cl poisoning resistance and good heat stability, and the reaction temperature is 300 ℃.

Chinese patent publication No. CN108295852A discloses a Ce-Zr catalyst for the oxidation reaction of chlorine-containing volatile organic compounds, in which Ru is loaded on Ce-Zr. The catalyst shows better stability in the degradation of p-chlorobenzene, and has better stability in the conversion rate of trichloroethylene reaching 90% at relatively low temperature (250 ℃).

The catalytic combustion method can achieve ideal treatment effect on specific organic chloride, but polychlorinated dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) by-products are easily generated when the temperature is 400 ℃ in the incineration process, and the polychlorinated dibenzodioxins and the polychlorinated dibenzofurans are chloric organic pollutants with high toxicity, high carcinogenicity and high durability.

Disclosure of Invention

The invention provides a phosphorylated perovskite type catalyst and a preparation method thereof, the preparation method is simple, and the prepared phosphorylated perovskite type catalyst can be applied to catalytic oxidation of chlorine-containing volatile organic compounds and has the advantages of high removal efficiency, fewer high-toxicity byproducts and the like.

The specific technical scheme of the invention is as follows:

a method of preparing a phosphorylated perovskite catalyst comprising the steps of:

(1) dipping the lanthanum-manganese perovskite in a phosphoric acid solution, and washing and drying after the dipping to obtain phosphorylated lanthanum-manganese perovskite;

(2) and (3) placing the phosphorylated lanthanum-manganese perovskite into a solution of an active component metal salt for dipping, and drying, calcining, grinding and screening after dipping to obtain the phosphorylated perovskite catalyst.

In the preparation method, firstly, lanthanum-manganese perovskite is soaked in phosphoric acid solution, characteristic phosphate radical groups are introduced on the surface of the lanthanum-manganese perovskite, then noble metal is introduced on the surface of the lanthanum-manganese perovskite in a loading manner, and the noble metal is converted into noble metal oxide after calcination. The lanthanum phosphate structure formed after phosphorylation has special zeolite-like pore channels, can allow water molecules or corresponding ions to freely move, and can store a large amount of zeolite-like water. The final prepared catalyst is thus able to tolerate high concentrations of water in the catalytic oxidation of dichloromethane.

Preferably, the lanthanum-manganese perovskite is a layered lanthanum-manganese perovskite.

The structural composition of the layered lanthanum-manganese perovskite ensures that the layered lanthanum-manganese perovskite has similar physicochemical properties with the perovskite, and has a stable and adjustable structure and abundant oxygen species. In addition, the presence of the layered structure also provides a more varied environment for oxygen atoms. The surface can form rich oxygen vacancies, which is beneficial to the adsorption of surface oxygen species and the oxidation of chlorine-containing volatile organic compounds.

Preferably, the preparation method of the layered lanthanum-manganese perovskite comprises the following steps:

(a) mixing a salt solution containing lanthanum and manganese elements with an acid solution to form a sol, drying the sol, and calcining at the temperature of 650-750 ℃ in an air atmosphere for 4-6h to obtain intermediate powder;

(b) and (3) keeping the intermediate powder at the constant temperature of 100-150 ℃ for 10-15h, washing, drying, and calcining at the temperature of 650-750 ℃ in an air atmosphere for 4-6h to obtain the layered lanthanum-manganese perovskite.

Salts containing lanthanum elements include lanthanum nitrate; the manganese element-containing salt comprises manganese nitrate and/or manganese chloride; the acid solution is citric acid and/or ammonium bicarbonate solution.

Too high or too low a phosphorus loading can reduce the catalytic activity of the catalyst. Preferably, the phosphorus loading is calculated by the mass percent of phosphorus element, and in the phosphorylated perovskite catalyst, the phosphorus loading is 0.1-5%; further preferably, the phosphorus loading amount is 0.3-1%; most preferably, the phosphorus loading is 0.5%.

Preferably, the active ingredient metal salt is at least one of soluble salts of gold, platinum, ruthenium and palladium.

Too high or too high loading of the active component metal can reduce the catalytic activity of the catalyst. Preferably, the loading amount of the active component metal is calculated by the mass percent of the active component metal element, and in the phosphorylated perovskite catalyst, the loading amount of the active component metal is 0.3-3%; further preferably 0.3-1%; most preferably 0.45%.

When the active component metal is loaded on the surface of the oxide, the temperature and the pH value of the solution influence the loading amount and the loading state of the active component metal, so that the temperature and the pH value of the solution in the reaction process need to be optimized.

Preferably, in the step (2), the mixture of the phosphorylated lanthanum-manganese perovskite and the active ingredient metal salt solution is heated to 30-80 ℃; and adjusting the pH value to 7-12; further preferably, the mixture of the phosphorylated lanthanum-manganese perovskite and the active ingredient metal salt solution is heated to 30-60 ℃; and adjusting the pH value to 8-10.

Preferably, in the step (2), the time for dipping the phosphorylated lanthanum-manganese perovskite in the active ingredient metal salt solution is 0.5-3 h.

Preferably, in the step (2), the calcination temperature is 500-600 ℃; the calcination time is 1-5 h.

The invention also provides an application of the phosphorylated perovskite catalyst in high-temperature hydrolysis degradation of chlorine-containing volatile organic compounds, which comprises the following steps:

reacting flue gas containing chlorine-containing volatile organic compounds and water vapor under the action of the perovskite catalyst;

in the flue gas, the content of water vapor is 1-10 vol%;

the reaction temperature is 150-600 ℃.

Preferably, the content of the water vapor in the flue gas is 2-6 vol%.

The catalytic oxidation performance of the phosphorylated perovskite on dichloromethane can be improved by properly increasing the content of water vapor in the flue gas, when the water passing amount is 5 vol%, the activation temperature is reduced by about 85 ℃ compared with the anhydrous condition, the complete conversion temperature is reduced by 50 ℃, the catalyst shows the optimal dichloromethane removal efficiency, and when the content of the water vapor is increased to 10 vol%, the catalyst still shows better catalytic activity.

Most preferably, the flue gas has a water vapour content of 5 vol%.

Preferably, the reaction temperature is 450 ℃ to 550 ℃.

The oxidation catalyst has better oxidation efficiency on chlorine-containing volatile organic compounds in a middle-high temperature region of 400-550 ℃, and particularly has the best catalytic efficiency in a temperature region of 450-550 ℃.

Compared with the prior art, the invention has the beneficial effects that:

(1) the preparation method is simple and convenient for industrial application, and the prepared catalyst has better catalytic activity and stability. For example, a catalytic reaction of dichloromethane at 500 ℃ with a Ru-doped catalyst can achieve 90% conversion. After the catalyst is continuously operated for 90 hours at the temperature, the conversion rate is not obviously reduced, and the stability of the catalyst is good.

(2) The whole reaction system for catalyzing and degrading the chlorine-containing volatile organic compounds avoids the generation temperature range (250-400 ℃) of high-toxicity byproducts dioxin, reduces the generation of polychlorinated high-toxicity byproducts such as dioxin and the like, and is more environment-friendly.

Drawings

FIG. 1 is a schematic structural view of an experimental apparatus used in application examples 1 to 5;

FIG. 2 is a graph showing the activation temperatures of catalysts prepared in example 1 and comparative example 1 for catalyzing methylene chloride;

FIG. 3 is a graph of water resistance test of the catalyst prepared in example 1 to catalyze methylene chloride;

FIG. 4 is a graph of stability test of the catalyst prepared in example 1 for catalyzing dichloromethane.

Detailed Description

Comparative example 1

Preparing a catalyst:

(1) salt solution a (lanthanum nitrate: manganese chloride dissolved in a molar ratio of 3:1.5: 0.5) and solution B (citric acid: ammonium bicarbonate dissolved in a molar ratio of 6: 5.7) 1: 1 (volume ratio), performing rotary evaporation at 70 ℃ to form sol, drying at 120 ℃, and roasting at 700 ℃ for 5 hours in an air atmosphere.

(2) Putting the powder obtained in the step (1) into a high-pressure reaction kettle, and keeping the temperature at 120 ℃ for 12 hours; then the sample is washed, dried and roasted again in the air at 700 ℃ for 2 hours, and the obtained sample is La₃Mn₂O₇。

(3) 1.0g of La₃Mn₂O₇Placing in 10ml of 0.5g/L metal salt ruthenium chloride solution, performing ultrasonic treatment, drying at 80 ℃ for 12h, calcining at 550 ℃ for 4h, and grinding and sieving into particles with the size of 40-60 meshes to obtain Ru/La₃Mn₂O₇Catalyst, ruthenium loading of the resulting catalyst was 0.45%.

Example 1

Preparing a catalyst:

(1) salt solution a (lanthanum nitrate: manganese chloride dissolved in a molar ratio of 3:1.5: 0.5) and solution B (citric acid: ammonium bicarbonate dissolved in a molar ratio of 6: 5.7) were mixed 1: 1 (volume ratio), performing rotary evaporation at 70 ℃ to form sol, drying at 120 ℃, and roasting at 700 ℃ for 5 hours in an air atmosphere.

(2) Putting the obtained powder into a high-pressure reaction kettle, and keeping the temperature at 120 ℃ for 12 hours; then the sample is washed, dried and roasted again in the air at 700 ℃ for 2 hours, and the obtained sample is La₃Mn₂O₇。

(3) 1g of La₃Mn₂O₇Placing the mixture into 30mL of 0.1mol/L phosphoric acid solution, uniformly stirring, performing ultrasonic treatment and washing at room temperature, and drying for 24 hours to obtain a phosphorylated sample, which is marked as La₃Mn₂O₇-P。

La₃Mn₂O₇The loading of phosphorus in P was 0.5%.

(4) 1.0g of La₃Mn₂O₇Putting P in 10ml of 0.5g/L ruthenium chloride solution to adjust the pH value to 8, carrying out ultrasonic treatment at 50 ℃ for 2h, drying at 80 ℃ for 12h, calcining at 550 ℃ for 4h, and grindingSieving to obtain 40-60 mesh particles to obtain Ru/La₃Mn₂O₇-P catalyst powder with ruthenium loading of 0.45%.

Example 2

Preparing a catalyst:

(1) salt solution a (lanthanum nitrate: manganese chloride dissolved in a molar ratio of 3:1.5: 0.5) and solution B (citric acid: ammonium bicarbonate dissolved in a molar ratio of 6: 5.7) 1: 1 (volume ratio), performing rotary evaporation at 70 ℃ to form sol, drying at 120 ℃, and roasting at 700 ℃ for 5 hours in an air atmosphere.

(2) Putting the powder obtained in the step (1) into a high-pressure reaction kettle, and keeping the temperature at 120 ℃ for 12 hours; then the sample is washed, dried and roasted again in the air at 700 ℃ for 2 hours, and the obtained sample is La₃Mn₂O₇。

(3) 1g of La₃Mn₂O₇Placing the mixture into 30mL of 0.06mol/L phosphoric acid solution, uniformly stirring, performing ultrasonic treatment and washing at room temperature, and drying for 24 hours to obtain a phosphorylated sample, which is marked as La₃Mn₂O₇P, phosphorus loading 0.3%.

(4) 1.0g of La₃Mn₂O₇Putting the-P into 10ml of 0.5g/L ruthenium chloride solution to adjust the pH value to 8, carrying out ultrasonic treatment at 50 ℃ for 2h, drying at 80 ℃ for 12h, calcining at 550 ℃ for 4h, and grinding and sieving into particles with the size of 40-60 meshes to obtain Ru/La₃Mn₂O₇-P catalyst powder with ruthenium loading of 0.45%.

Example 3

Preparing a catalyst:

(1) salt solution a (lanthanum nitrate: manganese chloride dissolved in a molar ratio of 3:1.5: 0.5) and solution B (citric acid: ammonium bicarbonate dissolved in a molar ratio of 6: 5.7) 1: 1 (volume ratio), performing rotary evaporation at 70 ℃ to form sol, drying at 120 ℃, and roasting at 700 ℃ for 5 hours in an air atmosphere.

(2) Putting the powder obtained in the step (1) into a high-pressure reaction kettle, and keeping the temperature at 120 ℃ for 12 hours; then the sample is washed, dried and roasted again in the air at 700 ℃ for 2 hours, and the obtained sample is La₃Mn₂O₇。

(3) 1g of La₃Mn₂O₇Placing the mixture into 30mL of 0.2mol/L phosphoric acid solution, uniformly stirring, performing ultrasonic treatment and washing at room temperature, and drying for 24 hours to obtain a phosphorylated sample, which is marked as La₃Mn₂O₇P, phosphorus loading 0.9%.

(4) 1.0g of La₃Mn₂O₇Putting the-P into 10ml of 0.5g/L ruthenium chloride solution to adjust the pH value to 8, carrying out ultrasonic treatment at 50 ℃ for 2h, drying at 80 ℃ for 12h, calcining at 550 ℃ for 4h, and grinding and sieving into particles with the size of 40-60 meshes to obtain Ru/La₃Mn₂O₇-P catalyst powder with ruthenium loading of 0.45%.

Example 4

Preparing a catalyst:

(1) 1.0g of La₃Mn₂O₇Putting the-P into 10ml of 0.35g/L ruthenium chloride solution to adjust the pH value to 8, carrying out ultrasonic treatment at 50 ℃ for 2h, drying at 80 ℃ for 12h, calcining at 550 ℃ for 4h, and grinding and sieving into particles with the size of 40-60 meshes to obtain Ru/La₃Mn₂O₇-P catalyst powder with ruthenium loading of 0.3%.

Example 5

Preparing a catalyst:

(1) 1.0g of La₃Mn₂O₇Putting the-P into 10ml of 1g/L ruthenium chloride solution to adjust the pH value to 8, carrying out ultrasonic treatment at 50 ℃ for 2h, drying at 80 ℃ for 12h, calcining at 550 ℃ for 4h, and grinding and sieving into particles with the size of 40-60 meshes to obtain Ru/La₃Mn₂O₇-P catalyst powder with ruthenium loading of 0.9%.

The experimental setup used in the following application examples is shown in fig. 1.

Application example 1

Testing the performance of the catalyst for catalytic oxidation of dichloromethane:

the activity test was carried out in a fixed bed reactor, and the catalysts prepared in comparative example 1 and example 1 were selected, respectively, with a loading of 1.0g and a particle size of 40-60 mesh. The initial gas concentration is 1000ppm of methylene chloride and [ O ]₂]＝10％,[H₂O]＝5％,N₂As carrier gas, GHSV (gas space velocity) ═ 12000h^-1. TestingThe reaction temperature is 200 deg.C, 250 deg.C, 300 deg.C, 350 deg.C, 400 deg.C, 450 deg.C, 500 deg.C, 550 deg.C, and the test result is shown in FIG. 2. As can be seen from fig. 2: the activity of the phosphorylated sample is obviously better than that of the non-phosphorylated sample, and the phosphorylation enhances the water resistance of the catalyst.

Application example 2

Testing the performance of the catalyst for catalytic oxidation of dichloromethane:

the activity experiments were carried out in a fixed bed reactor, with the catalysts prepared in examples 1 to 3 each being selected, the loading being 1.0g and the particle size being 40 to 60 mesh. The initial gas concentration is 1000ppm of methylene chloride and [ O ]₂]＝10％,[H₂O]＝5％,N₂As carrier gas, GHSV (gas space velocity) ═ 12000h^-1. The reaction temperature was measured at 200 deg.C, 300 deg.C, 400 deg.C, 500 deg.C, and the test results are shown in Table 1. As can be seen from Table 1: the optimum noble metal loading was 0.45%.

TABLE 1 catalytic Oxidation efficiency of catalyst for methylene chloride%

Application example 3

Testing the performance of the catalyst for catalytic oxidation of dichloromethane:

the activity test was carried out in a fixed bed reactor, and the catalysts prepared in example 1, example 4 and example 5 were selected, respectively, with a loading of 1.0g and a particle size of 40-60 mesh. The initial gas concentration is 1000ppm of methylene chloride and [ O ]₂]＝10％,[H₂O]＝5％,N₂As carrier gas, GHSV (gas space velocity) ═ 12000h^-1. The reaction temperature was measured at 200 deg.C, 300 deg.C, 400 deg.C, 500 deg.C, and the test results are shown in Table 2. As can be seen from Table 2: the optimum noble metal loading was 0.45%.

TABLE 2 catalytic Oxidation efficiency of catalyst on methylene chloride%

Application example 4

Testing the water resistance of dichloromethane catalyzed and oxidized by the catalyst:

the activity test is carried out on a fixed bed reactor, and the Ru/La prepared in example 1 is selected₃Mn₂O₇-P catalyst, loading 1.0g, particle size 40-60 mesh. The specific test procedure is as follows: firstly, in the reaction system (1000ppm DCM, 10 vol% O)₂) Introducing 5 vol% of water, and Ru/La at 340 DEG C₃Mn₂O₇The conversion rate of the-P catalyst to dichloromethane is about 70%, and after 120min of stabilization, the water amount is increased to 10 vol% for stability test under constant temperature condition. The test results are shown in FIG. 3. As can be seen from fig. 3: Ru/La₃Mn₂O₇The P catalyst has better resistance to high-concentration water vapor. The lanthanum phosphate with the pore structure has obvious hydrophilicity and water storage capacity, preferentially conducts and stores a large amount of water input from the outside, and prevents water molecules from gathering near active sites or competing with substrates for adsorption.

Application example 5

Metal modified phosphorylated perovskite catalyst stability testing:

the activity test is carried out on a fixed bed reactor, and the Ru/La prepared in example 1 is selected₃Mn₂O₇-P catalyst, loading 1.0g, particle size 40-60 mesh. The initial gas concentration is 1000ppm of methylene chloride and [ O ]₂]＝10％,[H₂O]＝5％,N₂As carrier gas, GHSV (gas space velocity) ═ 12000h^-1. The test reaction temperature was 500 ℃ and the test results are shown in FIG. 4. As can be seen from fig. 4: Ru/La₃Mn₂O₇the-P catalyst can maintain 95% of activity in the reaction of catalyzing and oxidizing the dichloromethane, has no deactivation phenomenon, and can stably run for a long time.

The above-mentioned embodiments are intended to illustrate the technical solutions and advantages of the present invention, and it should be understood that the above-mentioned embodiments are only specific embodiments of the present invention, and are not intended to limit the present invention, and any modifications, additions, equivalents, etc. made within the scope of the principles of the present invention should be included in the scope of the present invention.