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Preparation and CO Adsorption Performance of Supported CuCl Adsorbent

Author: LiLi
Tutor: LiRuiFeng
School: Taiyuan University of Technology
Course: Chemical Engineering
Keywords: CO adsorbent zeolite active carbon CuCl
CLC: X701
Type: Master's thesis
Year: 2010
Downloads: 265
Quote: 2
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Abstract

Carbon monoxide is the raw gas of many synthesized chemical products, but in some other chemical reactions it can make the catalyzer invalid and is the detrimental impurity in industrial gases. So, with the rapid development of industry and the increasing public environmental awareness, more and more attention is paid to energy saving and consumption reducing in the production. As a result, it has very important social and economical meaning to develop an effective and energy-saving technology in order to satisfy the needs of separating and purifying various gases in the tail gas and the industrial products containing carbon monoxide. The technology of pressure swing adsorption （PSA） or temperature swing adsorption （TSA） is a recently new-rising gas separation technology in industry. It makes use of the distinguishing adsorbing features of different gases by solid material, as well as the characteristic that the adsorbing quantity is changing with the change of pressure or temperature, to carry out the separation and purification of gases by the periodic pressure （temperature） change process. The adsorbent applied by PSA should have a great capacity of adsorbing and selectively separating the goal gases, which greatly affects the result of separation and the energy saving. The technology of PSA often takes the zeolite and active carbon as the adsorbents. This thesis is focusing on the preparation of the carbon monoxide adsorbent taking CuCl as the carrier through two methods.1. CO adsorbent synthesized by loading CuCl on zeolite at atomic levelIt is found that salts or oxides can disperse spontaneously onto the surface and into the pores of zeolite or other carriers to form a monolayer or submonolayer. According to this theory, zeolite can be modified by carrying CuCl to prepare CO adsorbents. In the thesis, 13X is modified by carrying CuCl and the adsorption performance of adsorbents is researched. When zeolite is mixed with CuCl and heated, high CO adsorption selectivity and capacity can be obtained. In addition, the influence of carriers such as 13X,NaY,NH4X to the adsorbent has been observed. As a result, it is found that the adsorbents 0.4gCuCl/g13X and 0.45gCuCl/gY have higher CO adsorption and CO/CO₂ selectivity. XRD shows that CuCl crystalline phase can disappear and change into monolayer dispersion state on the surface of the zeolite when it is heated at a suitable temperature. Since Cu+ ions on the surface can selectively form coordination bonds with CO and weaken the basicity of the surface, an adsorbent with higher capacity and selectivity of CO than that of CO₂ can be obtained.2. CO adsorbent synthesized by loading Cu2+ compounds to produce CuCl In the paper, the CuCl adsorbent, which is synthesized by using Cu2+ compounds as raw material and active carbon as carrier, and its capacity of adsorbing CO are researched. In addition, a series of conditions such as material proportion, the types of carrier and its load, activating temperature and environment, adsorption and desorption, regeneration, as well as the selection between CO and CO₂ are reviewed too. Since Cu+ ions on the surface can form coordination bonds with CO and weaken the basicity of the surface of carrier, an adsorbent with higher capacity of adsorbing and selecting CO than that of CO₂ can be obtained. Moreover, it has been found in the study that the best synthetic condition is that CuCl2/ （HCOO）2Cu=1, Cu（Ⅰ） /AC （mmol/g） =4, when the mixture is heated at 260℃for three hours under the environment of vacuum or 0.04MPa CO. The obtained adsorbent Cu（Ⅰ）/AC, under the temperature of 25℃and the environment of 0.1 MPa CO, will have the best adsorbing performance– the capacity of adsorbing CO can be up to 56 mL/g adsorbent; and it also has the best desorbing performance– the desorption capacity can be as high as 98% as well as the separation ratio between CO and CO₂ can be more than 2. In addition, the oxidized adsorbent can easily recover for use by heating at 120℃for three hours under the environment of 0.04MPa CO. XRD and N2 adsorption（77K）show that CuCl crystalline phase can monolayer dispersion state on the surface of the active carbon when it is heated at a suitable temperature. It is easier to prepare the Cu（Ⅰ） adsorbent than direct method.

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