CN1043311C - Zeolite adsorbing agent for carbon monoxide with high selectivity - Google Patents

Abstract

The present invention relates to a preparation method of a zeolite adsorption agent for adsorbing CO with high selectivity, which comprises the steps that NaY zeolite, metahalloysite clay and a hole expanding agent are mixed and formed by extrusion, and are processed by an NaOH water solution containing SiO2 to prepare a compound carrier, then Cu(II)-Y zeolite is formed by Cu <++> ion exchange, and finally, a finished product, namely a Cu(I)-Y zeolite adsorption agent, is prepared through the reduction of CO or H2. The adsorption agent can adsorb CO (when the concentration of the CO is 30 mmHg, the adsorption quantity is 3.13 mmol/g at the temperature of 250 DEG C, and the adsorption quantity is 2.57 mmol/g at the temperature of 50 DEG C) with high selectivity in gases of CO, N2, etc., and more than 80% of CO can be desorbed below 100DEG C. Consequently, the adsorption agent can be used for separating, recovering and preparing CO with high purity from industrial tail gas containing CO.

Description

The preparation method of the zeolite adsorbents of high selectivity absorption carbon monoxide

The invention relates to and use the alternating temperature absorption method, contain N from certain ₂, CO, CO ₂Gaseous mixture in select absorption or reclaim the preparation method of a kind of zeolite adsorbents of CO.

Usually the gas that contains CO comprises: steel mill's converter gas, air blast furnace gas, the furnace gas of getting angry that electric furnace gas and gas coke obtain.This kind gas great majority are used to do fuel to be used.If the CO that contains in this gas can be separated and with the work that high-purity reclaims, can be used as reducing agent, will bring bigger economic benefit to chemical industry.Separate and reclaim the method for CO from contain the CO gaseous mixture, at present known have a lot of methods, as low temperature treatment technology; The cuprous toluene solution of tetrachloroization absorbs the CO method; Method of the solid absorbent separation of C O of useful cupric etc. also.More close to technology of the present invention EP224, be raw material with the NaY zeolite in 150 (1986) documents, the method that adopts ion-exchange and dipping to combine is developed Cu (the I)-y-type zeolite adsorbent of molecular sieve of CuCl.At normal temperatures and pressures, this adsorbent can reach 45Nml/g to the adsorbance of CO, and improves with temperature, and the CO adsorbance changes little, opposite CO ₂And N ₂Adsorbance descend a lot.Proposing only serviceability temperature is about 90 ℃.Also have at U.S.4, in 019,879 patent, adopt silica-rich zeolite ZSM-5 Cu (NO ₃) ₂And CuCl ₂Carry out ion-exchange and dipping, then Cu (II)-ZSm-5 zeolite is found time to dewater at 100 ℃, handled several hours at 300 ℃ with CO then, make Cu (I)-ZSm-5 zeolite adsorbents.This sample CO dividing potential drop in the time of 50 ℃ is respectively 10,20,40,60,100, and the percetage by weight of corresponding CO absorption is 1.7,2.0,2.0,2.0 during 20mmHg, 2.0,2.0 COwt%.The result who also measures 250 ℃ of CO absorption simultaneously is, the CO dividing potential drop is respectively 10,100, and corresponding CO absorption is 0.5,0.5,0.5 COwt% during 200mmHg.But in above-mentioned several method for preparing Cu (I)-zeolite adsorbents, the zeolite adsorbents of acquisition is to the absorption of CO, and the desorb capacity is not high.

The purpose of this invention is to provide a kind of can be efficiently CO absorption selectively, and to CO ₂Cu (the I)-y-type zeolite preparation of adsorbent method of the very low copper ions of absorption, utilize this method gained, adsorbent can be used for from containing CO ₂, N ₂CO gas is reclaimed in the absorption of high selectivity in the gas.

Preparation of adsorbent method of the present invention comprises that the NaY zeolite that makes NaY zeolite and clay class kaolin, expanding agent mixing extrusion modling, drying, roasting, alkali treatment make the binder free type is the composite zeolite carrier of main body.Make Zeolite support and copper nitrate and/or copper chloride carry out ion-exchange and dipping then, make Cu (II)-Y zeolite adsorbents, use pure CO or H again ₂Cu (II) is reduced into Cu (I), and makes Cu (I)-Y zeolite adsorbents.

In the invention described above preparation of adsorbent method, it is characterized in that: 1) the NaY zeolite is in following ratio (weight) with halloysite class clay and expanding agent mixing extrusion modling:

NaY: clay=(0.5～0.8): (0.2～0.5)

(NaY+ clay): expanding agent=100: 0.2; And, the SiO in the clay ₂/ Al ₂O ₃Should be 1.5～2.5, its burning decrement should be in 15～20% (wt) scope; So-called expanding agent is organic matters such as sodium cellulosate, sesbania powder, starch.2) alkali treatment is with containing SiO ₂Concentration be the NaOH solution (waterglass) of 0.5～2.0N, heat-treated 2～20 hours in 95～98 ℃.

3) ion-exchange be week 0.2～1.0N copper nitrate and/or copper chloride solution exchange and flood the Na after the ion-exchange in the carrier zeolite ₂O has 85% above equivalent by Cu ⁺⁺Exchange.

For making the Cu after ion-exchange ⁺⁺Ion can be reduced into Cu as far as possible ⁺Ion, it is with pure CO or H ₂Reduction is reflected at and carried out under 300～350 ℃ 1～20 hour.Under this reducing condition, the Cu in the carrier ⁺⁺Ion will be transformed into Cu more than 85% equivalent will be arranged ⁺Ion.

In addition, for improving the performance of adsorbent, zeolite is being carried out Cu ⁺⁺Can give processing to zeolite before the ion-exchange, it gives and handling is to carry out roasting 2～10 hours under 350～650 ℃ of temperature.Below by example preparation method of the present invention is given to illustrate further.

Example 1 is got 80 and is restrained the NaY zeolites, adds 20 gram clays, adds 0.2 gram cellulose again and receives in (or sesbania powder), and add water and mix, extrusion modling (1～2mm), dry under 110 ℃ then, 550 ℃ of following roastings 2 hours, contain 3 gram SiO with 0.8N at last ₂The waterglass of NaOH is dissolved in 95～89 ℃ to be handled 4 hours down, filtered, washs drying under 110 ℃, promptly made the composite zeolite carrier based on the Y type.

Example 2 is put into 100 ml waters to Zeolite support 40 grams that example 1 makes, with 18.5 gram CuCl in 500 milliliters of round-bottomed flasks ₂Copper nitrate is dissolved in 290 ml waters, then with after two kinds of mixing of materials, under agitation exchanges 4 hours down in 80 ℃, promptly obtains CuCl after filtration washing, the drying ₂Cu (II)-Y-2 adsorbent.

Example 3 preparation methods just soak CuCl with example 2 ₂Before under 650 ℃, carry out roasting 2 hours, carrier is given processing, make Cu (II)-Y-3 adsorbent.

Example 4 takes by weighing 80mg to the adsorbent of example 2 methods preparations, puts into the vacuum electronic balance, finds time 2 hours in 350 ℃, leads to into 50mmHg CO, and reductase 12 hour is extracted CO then out, cools to adsorption temp.With gravimetric detemination CO, CO under different temperatures pressure ₂Absorption, the desorption rate of the one pack system on Cu (I)-Y-2 zeolite the results are shown in table 1abcd:

Table 1a CO is at Cu (I)-last adsorpting data of Y-2

Table 1d CO ₂Desorption data on Cu (I)-Y-2

Desorption temperature (℃)	Same t (branch) during desorption	Desorption rate (mmol/g)	Desorption %
				25℃	10	0.35	53.8
100	10	0.63	96.9
				150	8	0.63	96.9
200	4	0.63	96.9

Table 1b CO ₂Adsorpting data on Cu (I)-Y-2

The desorption data of table 1C CO on Cu (I)-Y-2

Desorption temperature (℃)	Desorption time t (branch)	Desorption rate (mmol/g)	Desorption %
				25℃	8.0	0.57	25.2
80	8.0	1.40	61.9
				100	4.0	1.74	76.9
150	4.0	2.23	98.7
				200	2.0	2.25	99.6

Example 5: Cu (the I)-Y-3 adsorbent of above-mentioned example 3 preparations is got 80mg, and assay method is measured it to CO, CO with example 4 ₂The adsorption/desorption amount, the results list 2a, b, c, d:

The adsorpting data of table 2a CO on Cu (I)-Y-3

Table 2d CO ₂Desorption data on Cu (I)-Y-3

Desorption temperature (℃)	Desorption time t (branch)	Desorption rate (mmol/g)	Desorption %
				50℃	5	0.08	15.7
100	10	0.27	51.9
				150	10	0.38	67.9
200	8	0.44	72.1
				250	4	0.48	75.0

Table 2b CO ₂Adsorpting data on Cu (I)-Y-3

The desorption data of table 2C CO on Cu (I)-Y-3

Desorption temperature (℃)	Desorption time t (branch)	Desorption rate (mmol/g)	Desorption %
				50℃	8.0	0.97	37.7
100	8.0	2.06	80.7
				150	4.0	2.53	98.4
200	2.0	2.55	99.2
				250	2.0	2.56	99.6

By above-mentioned example, the capacity that the adsorbent that utilizes the inventive method to make has CO absorption is big, and when 50 ℃ of absorption, CO Cu (I)-Y zeolite adsorption CO under 30mmHg is 2.57mmol/g, and 25 ℃ of absorption are to being 3.13mmol/g.When 100 ℃ of following desorptions, the CO desorption more than 80% can be come out, during 150 ℃ of desorptions, can get 98% CO desorption and come out.When 50 ℃ of CO absorption ₂The time, CO ₂Adsorbance only is 0.64mmol/g during 30mmHg.

Because adsorbent of the present invention has the cnmplexation adsorbability with CO, and CO is being arranged ₂, N ₂Deng can high selectivity in the gas CO absorption, and can be, so this adsorbent has practicality widely at 100 ℃ of left and right sides desorptions greater than 80% CO.

Claims (2)

1. a preparation method who is used for the zeolite adsorbents of high selectivity CO absorption is that the composite zeolite carrier based on the NaY zeolite is made in drying, roasting, again through ion-exchange and dipping, with Cu with NaY zeolite and clay mixed-forming ⁺⁺Ion is supported on the carrier, and makes Cu (I)-Y type adsorbent through reduction, it is characterized in that:

1) the NaY zeolite is in following ratio (weight) with halloysite class clay and expanding agent mixing extrusion modling:

NaY: clay=(0.5～0.8): (0.2～0.5)

(NaY+ clay): expanding agent=100: 0.2; And, the SiO in the clay ₂/ Al ₂O ₃Should be 1.5～2.5, its burning decrement should be in 15～20% (wt) scope; So-called expanding agent is sodium cellulosate, sesbania powder, starch;

2) alkali treatment is with containing SiO ₂Concentration be the NaOH solution of 0.5～2.0N, heat-treated 2～20 hours in 95～98 ℃;

3) before ion-exchange zeolite is given processing, giving processing is to carry out roasting 2～10 hours under 350～650 ℃ of temperature.

2. in accordance with the method for claim 1, it is characterized in that reduction process uses pure CO or H ₂Make reducing gases, under 300～350 ℃, carry out 1～20 hour reduction reaction.