CN1185353A

CN1185353A - Catalyst for purifying nitrogen-contained gas to remove carbon monoxide and course thereof

Info

Publication number: CN1185353A
Application number: CN96117226A
Authority: CN
Inventors: 姚虎卿; 凌泽荣; 李承涛; 刘晓勤; 马正飞
Original assignee: NANJING CHEMICAL UNIV
Current assignee: NANJING CHEMICAL UNIV
Priority date: 1996-12-20
Filing date: 1996-12-20
Publication date: 1998-06-24
Anticipated expiration: 2016-12-20
Also published as: CN1085114C

Abstract

The invention relates to a chemical separation technology, which is designed to solve volume and stability of catalytic adsorbent for cleaning micro-quantity of carbon monoxide from nitrogen-containing gas. It is characterized by that it uses cupric chloride, active carbon, natural high-quality concave-convex rod earth and mixed rare earth chloride through the processes of soaking or/and mixing and forming to obtain granular purification catalyst. Under the condition of temp. of 0-55 deg.C and pressure of 0.5-2.5 MPa, it can implement the temp.-changing adsorption and pressure-changing adsorption for cleaning micro carbon monoxide from nitrogen-containing gas, so that it can be extensively used in the ammoia preparation, organic chemical and metallurgy industries.

Description

Contain carbon monoxide cleaning catalyst and process in the nitrogen

The present invention belongs to the chemical separating field for a kind of transformation absorption implementation procedure that purifies the catalyst of micro CO in the nitrogenous gas and adopt this catalyst.

In industrial production such as system ammonia, organic chemical industry, metallurgy, all to run into from H ₂-N ₂Remove the micro CO problem in gaseous mixture and other nitrogenous gas.Generally in purifying nitrogenous gas, during micro CO, mainly contain two kinds of chemical method and physics methods.Representative having is following several: (1) removes H with the cuprammonia chemical absorption method ₂-N ₂Micro CO in the gaseous mixture.This method major defect is that energy consumption is big, complicated operation, cost height; (2) with Raney nickel catalyzing carbon monoxide is converted into methane.This method is better than chemical absorption method, but needs to handle the methane that generates, and the process energy consumption is increased; (3) the pressure swing adsorption method removal of carbon monoxide of employing physical absorption.This method only is suitable for unazotized gas, because of the physical absorption ability of nitrogen and carbon monoxide is close, this method is used for the situation of nitrogenous gas, does not reach the purpose that removes micro CO; (4) adopt the carbon monoxide cleaning catalyst, mainly contain with the palladium metal and be the catalyst of active component and be active component, load on the catalyst (US P4019879 petrochemical industry (19) 1990.443) on Y zeolite or the active carbon with the copper metal.Palladium metal catalyst costs an arm and a leg, and only is used for the very little occasion of gas treatment amount; The reacting dose of carbon monoxide on copper-loaded Y zeolite or active carbon is less, be about 2～3% (wt), and copper-loaded Y zeolite catalyst stability is relatively poor.

The present invention purifies for satisfying micro CO in the nitrogenous gas, overcomes the shortcoming of process and method in the past and a kind of efficient, stable carbon monoxide cleaning catalyst that proposes and the transformation absorption implementation procedure that adopts this cleaning catalyst thereof.

The preparation of micro CO cleaning catalyst realizes through the following steps: (1) preparation copper chloride and the mixed chlorinated aqueous solution or copper chloride and mixed chlorinated rare earth powder on rare: (2) with powdered activated carbon put into above-mentioned aqueous solution dipping or with above-mentioned powder; (3) for the situation that adopts immersion process for preparing, the solid mixture of parting liquid solid mixture, dry gained; (4) solid mixture of gained and high-quality attapulgite mixing aftershaping; (5) forming mixture 1-5 hour of heating, dry gained, suitable temperature was 100 ℃ and 400 ℃; (6) in reducing atmosphere the forming mixture of gained is reduced processing, suitable reducing atmosphere is a hydrogen or/and the gas of carbon monoxide, and temperature is 120～380 ℃, the micro CO cleaning catalyst.

The active carbon that is used for the cleaning catalyst preparation is advisable with powdery, and general commercial powdered activated carbon can satisfy granularity requirements.Active carbon is further characterized, and the specific surface that shows active carbon is 400～1400m ²/ g, that suitable is 700～1100m ²/ g.

When the aqueous solution of step (1) preparation copper chloride and mixed chlorinated rare earth, add a spot of acid and promote dissolving and improve temperature to be necessary.Suitable acid can be hydrochloric acid, sulfuric acid, oxalic acid and phosphoric acid, and suitable acid concentration is 0.1～1 equivalent, and temperature is 50～95 ℃.In step (6), between recovery time and reduction tolerance approximate linear is arranged, the suitable time is 3～5 hours, air speed is 60～120/ hours.

In catalyst, mixed chlorinated rare earth is generally 0.01～0.5: 1 with the ratio of the weight of active carbon, and situation is 0.02～0.3: 1 preferably; Copper chloride is generally 0.01～0.5: 1 with the ratio of the weight of active carbon, and suitable situation is 0.02～0.25: 1.

Reducing gas can be the admixture of gas of hydrogen or hydrogen, and the reducing gas hydrogen content is high more, and then reduction temperature is relatively low.For the situation of reducing with hydrogen, suitable reduction temperature is 140～300 ℃.

Prepare about 1kg micro CO cleaning catalyst example: the mixed chlorinated rare earth of 0.1kg copper chloride and 50g is put in the aqueous hydrochloric acid solution of 5 liters of 0.1N, be warming up to 90 ℃ and make the solid dissolving, the 0.8kg powdered activated carbon is added in the solution flooded about 2 two hours.Subsequently with activated carbon filtration, about 3 hours of 100 ℃ of dryings; The attapulgite mixed-forming of dried active carbon and 0.1kg.In temperature is that 350 ℃, air speed are 120hr ^-1Nitrogen atmosphere in, handled active carbon about 4 hours; Be that 220 ℃, air speed are 120hr in temperature subsequently ^-1Reducing atmosphere (N ₂: H ₂=1: about 3) in, handles active carbon about 5 hours, promptly get the micro CO cleaning catalyst.

In being filled with the fixed bed of this cleaning catalyst, the hydrogen nitrogen mixed gas that contains micro CO is by this bed, and condition and the result who obtains are as shown in the table:

Condition example 1 example 2

Temperature, ℃ 40 10

Pressure, Mpa 1.6 0.6

Break once the time, min 32 416

Gas composition, V%

H ₂ 72.7 74.5

N ₂ 24.1 25.2

CO 3.2 0.3

(CO＜5ppm), ml/g 20.5 16.8 for adsorbance when breaking once

The result shows in the table: for different carbon monoxide gas concentrations, use this cleaning catalyst, exit gas can both reach the purpose of high purification micro CO, and cleaning catalyst has suitable capacity.

The realization system that uses this catalyst to purify micro CO in the nitrogenous gas can be the alternating temperature absorption or the pressure-swing absorption process of filling bed, but suitable mode is to adopt the transformation absorption mode.Have two catalyst beds in the system at least, select to adsorb micro CO, and the serialization of implementation procedure.During with the pressure swing adsorption purge carbon monoxide, the adsorptive pressure of absorption process will be more than atmospheric pressure, as 0.5～2.5MPa, and the regeneration used atmosphere is depressed or the vacuum outgas operation, as adopting the vacuum outgas operation, its vacuum then will be below atmospheric pressure, as 10～80kPa.

Be suitable for gaseous mixture of the present invention, remove N ₂Outside trace amounts of CO, also contain the CH of trace ₄, H ₂O, H ₂S and NH ₃Deng impurity.Before entering purification carbon monoxide operation, need establish preposition operation, remove these micro-impurity, but remove CO ₂Operation then needn't be provided with.

During with alternating temperature adsorption method for purifying carbon monoxide, the adsorption temp of absorption process is good with 0～40 ℃, and the degassing temperature of degassing process then is advisable with about 110～190 ℃.

With the operation of pressure swing adsorption method purification micro CO, be to adopt several adsorbent beds that are filled with above-mentioned cleaning catalyst to carry out.For the following situation of regeneration of atmospheric pressure, each adsorbent bed all through absorption, all pressure drops, contraryly put, clean, equal operations such as voltage rise and final rise pressure, each operation is carried out in each adsorbent bed in order repeatedly.

1. unstripped gas is sent into adsorbent bed and is carried out the CO absorption operation, and when the after-stage of absorption process, with the portioned product pneumatic transmission to another confession boost (II) operation and other matting of usefulness;

After 2 absorption process are finished, this adsorbent bed and another are connected through the adsorbent bed that cleans, two realizations are all pressed, finish equal pressure drop for such one, another bed is finished equal voltage rise simultaneously;

3. the adsorbent bed through equal pressure drop carries out the reverse pressure operation of putting, and pressure is reduced to about atmospheric pressure;

4. feed portioned product gas to the adsorbent bed that subtracts overvoltage, remove remaining impurities gas in the bed, promptly carry out matting;

5. utilize the equal pressure drop gas of other adsorbent bed, realize the operation of equal voltage rise;

6. utilize the product gas of other adsorbent bed to finish absorption process final rise pressure operation before.

By in each adsorbent bed, carrying out aforesaid operations successively repeatedly, promptly remove the carbon monoxide of trace in the nitrogenous gas serially like this.

Claims

1 one kinds of catalyst that purify micro CO in the nitrogenous gas, it is characterized by: by copper chloride, active carbon, natural high-quality attapulgite and four kinds of raw materials of mixed rare earth chlorides, through dipping or/and mix, the catalyst granules of reprocessing moulding, in 0～55 ℃ temperature, be used for purifying the carbon monoxide of nitrogenous gas trace.

2 one kinds of pressure-swing absorption processes that adopt aforesaid catalyst to purify micro CO in the nitrogenous gas is characterized by: a plurality of fixed beds that catalyst is housed realize removing continuously micro CO in the nitrogenous gas by changing bed layer pressure in order.