CN1030375C - Modified molecular sieve adsorber for sulfur hexafluoride gas purification and its process - Google Patents

Abstract

The present invention relates to a modified A and X molecular sieve absorber for sulfur hexafluoride gas purification, which is modified by A molecular sieves or X molecular sieves of Ca ion pairs or Mg ion pairs and Li ion pairs or K ion pairs. In the process of preparing the absorber, sodium cellulose or sesbania powder is added as a structural adjusting agent of an adhesive and the absorber. Simultaneously, before calcination, silicate solution is used for immersion. The absorber is used for SF6 electrical equipment. The present invention effectively eliminates various poisonous gases produced in the operation of the equipment and in SF6 gases, prolongs the service life of the equipment, and avoids toxic hazard to maintainers. In addition, the absorber has the advantages of weak adsorption capability for the SF6 gases, strong adsorption capability for the poisonous gases and water, high speed, high anti-pressure strength, good abrasive resistance performance and long-term use.

Description

Modified molecular sieve adsorber for sulfur hexafluoride gas purification and its process

The present invention relates to a kind of adsorbent and preparation method thereof, specifically a kind ofly be used to remove SF ₆In the electric equipment, SF ₆By the hypertoxic low-fluorine sulfide impurities that produces after arcing or the spark discharge, the adsorbent of acidic materials and moisture content etc. and its preparation method.This adsorbent also is applicable to any system with above-mentioned gas, as industrial production SF ₆Gas cleaning etc.

The sulfur hexafluoride electric equipment be a kind of have nontoxic, insulating capacity is strong, arc extinguishing waits the electric equipment of excellent performance rapidly.Yet SF ₆The impurity of in manufacture process, leaving over and under the high temperature action of electric arc, the micro-low-fluorine sulfide impurities that decomposes by electrolysis and ionization, all belong to hypertoxic gas, the infringement human lung, the serious harm operator ' s health, and when minor amount of water existed, these low-fluorine sulfides decomposed generation HF, SO gradually ₂And H ₂SO ₃Deng strong corrosive material, not only harmful, and the heavy corrosion electric equipment, influence the electric equipment performance.All adopt both at home and abroad at present and in electric equipment, place adsorbent to remove the method for objectionable impurities gas.Normally used adsorbent has activated alumina and synthetic zeolite class.So far, relevant reported in literature biases toward the low-fluorine sulfide toxicity test more and measures SF both at home and abroad ₆Impurity content standard, and to adsorbent preparation, adsorption capability of different absorbate and to remove the research reports such as effect of above-mentioned impurity less.As at Elekfrotech, oh2 1979 68(4), 216-20 has reported when the power circuit switch disconnects, and uses Al ₂O ₃Absorption SF ₆The toxicity low-fluorine sulfide that decompose to generate is at Enorgetlle 1976(11), 13-14(Rnss) reported with Polysorob and adsorbed SF ₆The low-fluorine sulfide that decomposes.Inventor of the present invention once proposed to utilize the 5A of modification and LiX mixed molecules sieve adsorbant (CN85102711) to remove SF ₆In the electric equipment after arcing and spark discharge, SF ₆The hypertoxic low-fluorine sulfide gas that decomposition and ionization produce.The objective of the invention is on the basis of CN85102711 technology, provide a kind of and be adapted at a large amount of SF ₆Gas exists down, more can remove SOF effectively ₂, SO ₂, HF and S ₂F ₁₀The adsorbent of molecular sieve of toxic gases such as O.This adsorbent also can be used for industrial production SF simultaneously ₆Low-fluorine sulfide in the gas, impurity such as sour gas and moisture content.

Technology provided by the present invention once proposed to carry out on (CN85102711) technical foundation improved present inventors.Because at SF ₆Gas behind electric arc and electrion, divide vent one's spleen in key component be SOF ₂, SO ₂And HF ₆Exist.For adapting at a large amount of SF ₆Gas exists down, removes above-mentioned molecular size, the impurity that character is different, this adsorbent is to mix with the A of different pore sizes and X molecular sieve, in conjunction with using different ions (Ca, Mg, K, Li etc.) effect of modification, thus adsorbent is had concurrently select shape absorption and to big molecule such as S ₂F ₁₀The energy of adsorption of O.Adsorbent specifically provided by the present invention is that the A that mixes with certain proportion and X type molecular sieve are as Main Ingredients and Appearance, utilize Ca or Mg and Li or K ion to carry out A or X molecular sieve that modification must contain Ca or the Mg of Li or K, add the mixed molecules sieve adsorbant that binding agent clay and sodium cellulosate or sesbania powder obtain as the pore structure mediator agent of binding agent and adsorbent, it forms percentage by weight: mixed molecular sieve: 70～85%, the modification ion, Ca or Mg and K or Li ion: 0.2～1.5%; All the other are clay.And in the mixed molecular sieve ratio of A type molecular sieve and X type molecular sieve be 1: 1～3(Wt).In above-mentioned adsorbent, its preferable molecular sieve modified process is to adopt Ca, K ion and A type, and Mg, Li ion and X type molecular sieve, the A type molecular sieve that promptly obtains containing K, Ca ion with contain Li, the X type molecular sieve of Mg ion mixes by a certain percentage and is made into mixed molecular sieve.The various physical properties of the adsorbent that is provided are: surface area 380～480m ²/ g, adsorpting water quantity are 20～24%(wt), and heap is made a gesture of measuring 0.7～0.75 gram/ml, particle size diameter 2-3mm, intensity＞10kg/2.5mm and dry linting not.Be applicable to normal temperature, static state, dynamically absorption.Use this adsorbent can be with SF ₆SOF in the gas ₂, SO ₂, S ₂F ₁₀O, SO ₂F ₂, the content that is removed to that impurity such as acid gas, moisture content are high-speed is＜1ppm.

Preparation of adsorbent method provided by the present invention adopts following step:

1, gets 4A or NaX molecular sieve, in the soluble-salt solution that contains Ca or Mg and Li or K ion (chloride or nitrate), carry out ion-exchange respectively, make the Ca that contains Li or K or A type or the X type modified molecular screen of Mg.The ion-exchange ion exchange technique of molecular sieve is routinely carried out one or many under 80～95 ℃, after the ion-exchange, after filtration, be washed till no Cl or NO with deionized water ^- ₃Ion.

2, above-mentioned A type that contains Ca or Mg and Li or K or the X type molecular sieve that obtains mixed in 1: 1～3 ratios, add again by the clay of adsorbent weight 10～25% and in 0.2～1.5% ratio adding sodium cellulosate or the sesbania powder of molecular sieve and clay gross weight, mix moulding, drying.Drying can be carried out through air dry or oven dry in 20-150 ℃.

3, above-mentioned material after drying carries out drying through the process with 2 again with the silicate solutions dipping that contains 10-25%.

4, soak the dried material of silicate,, technology of the present invention is done explanation in further detail below by example after 400-650 ℃ of roasting more than 1 hour, can obtain adsorbent of the present invention.

Example 1: adsorbent preparation

(1) 10 gram LiNO ₃, 0.5 the gram Mg(NO ₃) ₂Be dissolved in the 500ml deionized water, treat dissolving fully after, add 100 gram NaX type molecular sieves, under 80-95 ℃ of condition, stir exchange 3 hours, cross Shanghai, be washed till no NO with deionized water ^- ₃Till, Shanghai is also following dry 3 hours at 130 ℃.

(2) 20 gram CaCl ₂, 2 gram KCl, soluble in water, add 100 gram 4A molecular sieves, in 80-95 ℃ of exchange 3 hours, cross Shanghai under stirring, be washed till no Cl ^-Till.Sample was in 130 ℃ of dryings 3 hours.

(3) get the sample that 60 gram (1) kind methods make, get the sample that 40 gram (2) kind methods make, add 20 gram clays and 0.2 gram sesbania powder or sodium cellulosate mixing aftershaping, use 15-25%(Wt after drying or the roasting) silicate handle, 130 ℃ dry down in 550 ℃ of roastings 3 hours, makes finished product.

(4) get (1) 40 gram and (2) 60 grams, add 25 gram clays, add 0.2 gram sesbania powder mixed-forming, dry back made finished product in 3 hours in 550 ℃ of roastings.

Example 2: the performance test 1 of adsorbent,

(1) use-case 1(3) gained adsorbent 2 grams charge into 2.3 liters SF are housed ₆Decomposition gas 5Kg/cm ²The absorption narrow-necked earthen jar in, carry out static state absorption, through the interval of certain hour, measure after absorption residual low-fluorine sulfide impurities content in the gas.

(2) for having adsorbed a period of time SF afterwards ₆Divide (the SO that vents one's spleen ₂, SOF ₂, S ₂H ₁₀The O residual content adopts chromatography to detect.Mainly adopt its acid number of measurement for various sulfur-bearing components, the method for hydrolyzable fluoride, the result who measures the acid number gained is an aggregate data, SF ₆Divide all kinds of catabolite major parts in venting one's spleen to be absorbed by alkali lye.Can comprehensively weigh adsorbent to various SF with this value ₆The adsorption effect of catabolite, thereby the performance of mensuration adsorbent.

(3) SF ₆Impurity content is SO among the raw material ₂2500PPm; SOF ₂Be 140PPm; S ₂F ₁₀O is 270ppm; Acid number is that 887ppm(is in HF); The hydrolyzable fluoride is 438ppm.SO ₂F ₂1080ppm。

Result of experiment is listed in table 1 and table 2.Table 1 is the adsorption capacity of adsorbent to acidic materials, finds out that with data in the table this adsorbent is very fast to the adsorption rate of acidic materials, only 887PPm can be reduced to＜5PPm with 48 hours.The hydrolyzable fluoride is reduced to＜2PPm by 438PPm.It is very short that adsorbate reaches equilibration time.

Table 1 adsorption experiment result

Absorption back residual impurity content PPm(V)

The adsorption time acid number is (with HF hydrolyzable fluoride

(hour) meter PPm) (SOF ₂, HF, SF ₄) ppm

0 887 438

6 26 7

12 9 2

24 6 2

Table 2 adsorption experiment result 2

Adsorption time (hour) absorption back residual impurity content PPm(V)

SO ₂SOF ₂S ₂F ₁₀O

0 2500 140 270

6 388 1 152

14 88 1 128

30 28 1 100

48 4 1 7

Claims (3)

1, a kind of sulfur hexafluoride gas purification adsorbent of molecular sieve, it is characterized in that molecular sieve is to contain the Ca of Li or K or A type and two kinds of molecular sieves mixing of the X type molecular sieve composition of Ma, the percentage by weight of its composition is: molecular sieve: 70～85%, Ca or Mg and Li or K ion are 0.2～1.5%, and all the other are clay; A type in its molecular sieve: the weight ratio of X type is 1: 1～3.

2,, it is characterized in that molecular sieve adopts the CaA type molecular sieve that contains K to mix by a certain percentage with the MgX type molecular sieve that contains Li according to the described adsorbent of claim 1.

3, a kind of being used for by the described preparation of adsorbent method of claim 1, it comprise adopt ion exchange technique with modification ion-exchange to molecular sieve, the adding additives moulding, the drying and roasting process is characterized in that:

(1) cellulose or the sesbania powder of adding mixed material total amount 0.2～1.5% before moulding;

(2) material floods with the silicate solutions that contains 10～25%, and then carries out drying and roasting behind shaping and drying.