CN103484170A - Cerium lanthanum-based desulfurizing agent and preparation method thereof - Google Patents

Abstract

The invention discloses a cerium-lanthanum-based desulfurizer and a preparation method thereof. The cerium-lanthanum-based desulfurizer first adopts a dry mixing method to mix cerium oxide, lanthanum oxide, a pore-forming agent and a binder to obtain a powder mixture Then, the obtained powder mixture is mixed with a planetary ball mill, and the obtained ball mill powder is dried in a vacuum drying oven at a temperature of 150°C for 2 hours and extruded into strips, and then placed in a muffle furnace at a temperature of 10°C/ Raise the temperature at a rate of 600-1000°C for 4 hours at a constant temperature and sinter for 4 hours. After natural cooling, the cerium-lanthanum-based desulfurizer is obtained. The amounts of cerium oxide, lanthanum oxide, pore-forming agent and binder are calculated by mass ratio. That is, cerium oxide: lanthanum oxide: pore former: binder is 15:4.5-6.5:1-1.5:1. The cerium-lanthanum-based desulfurizer of the invention has high desulfurization efficiency, simple preparation scheme, wide application prospect and high social and economic value.

Description

A kind of cerium-lanthanum-based desulfurizer and preparation method thereof

technical field

The invention relates to a cerium-lanthanum-based desulfurizer and a preparation method thereof.

Background technique

Usually, in addition to CO, H, CH and other gaseous hydrocarbons, there are impurities such as COS, H ₂ S, dust, halides, alkali metals and tar vapor in the gas, which will cause corrosion and damage to subsequent systems, especially gas turbines. Wear and tear can also be harmful to the environment.

The integrated gasification combined cycle (IGCC) power generation system is a new clean power generation technology with high efficiency and low pollution. In the IGCC power generation system, the purification of crude gas is a key link, which mainly includes dust removal and desulfurization. At present, there are two common desulfurization methods: low-temperature desulfurization and high-temperature desulfurization. Both methods have been applied in related occasions. Among them, high-temperature desulfurization has obvious advantages because it can improve efficiency, simplify the process and reduce costs. However, high-temperature desulfurization has obvious advantages. The key lies in the development of desulfurizers. Desulfurizers based on cerium oxide have attracted extensive attention from many researchers in recent years. Cerium oxide-based desulfurizers are also known as the second-generation high-temperature gas desulfurizers. For pollutants in coal gas, the development of desulfurizers with more obvious effects and higher desulfurization efficiency is the key to high-temperature desulfurization, and the mixed use of high-efficiency oxide desulfurizers will be a good research direction.

In order to make the IGCC unit operate normally and achieve high reliability, the gas must be desulfurized and purified before it enters the gas turbine. In the high-temperature desulfurization method adopted for desulfurization of IGCC power generation system, the desulfurizer is the key. The currently published patents include:

1. Yu Jianglong, Xie Wei, Chang Liping, Xie Kechang, Wang Dehai, etc. from Shenyang Institute of Aviation Industry invented the high-temperature gas desulfurizer and its desulfurization device with fly ash as the carrier, patent number: 200710158238.7;

2. Zheng Xianrong, Chang Liping, Wang Jiancheng, Bao Weiren, Xie Kechang, Jin Qingmai, etc. from Taiyuan University of Technology invented the zinc oxide medium-high temperature gas fine desulfurizer and its preparation method, patent number: 200910175382.0;

3. Manganese-lanthanum high-temperature gas desulfurizer and preparation method invented by Guo Shuqiang, Li Deqi, Ding Weizhong, Pan Jinbo, Li Yulong, etc. of Shanghai University, patent number: 201010616929.9;

4. The cerium-iron oxide high-temperature gas desulfurizer and its preparation invented by Guo Bo, Chang Liping, Miao Maoqian and Zhang Zhilan of Taiyuan University of Technology, patent number: 200710139672.0;

5. An improved high-temperature desulfurizer and its preparation method invented by Liu Yuzhen and Li Jingbin of Beijing Sanju Environmental Protection New Materials Co., Ltd., patent number: 200810113632.3.

The above desulfurization agent patents focus on zinc oxide, cerium oxide, etc., and their desulfurization efficiency is generally around 80%-90%, which fails to take advantage of the advantages of mixing various metals to improve desulfurization efficiency. The invention mixes cerium oxide and lanthanum oxide according to a certain ratio to prepare a desulfurizing agent, which has the advantages of easy synthesis, low cost and high efficiency, and proposes a new preparation method and application of a high-temperature desulfurizing agent.

Contents of the invention

One of the objects of the present invention is to provide a cerium-lanthanum-based desulfurizer, which has the advantages of easy synthesis, low production cost, and high desulfurization efficiency.

The object of the present invention is to provide a method for preparing the above-mentioned cerium-lanthanum-based desulfurizer.

Technical scheme of the present invention

A cerium-lanthanum-based desulfurizer prepared by a method comprising the steps of:

That is, firstly, the dry mixing method is used to mix cerium oxide, lanthanum oxide, pore-forming agent and binder to obtain a powder mixture;

Then, the obtained powder mixture is mixed with a planetary ball mill, and the obtained ball-milled powder is dried in a vacuum drying oven at a temperature of 150°C for 2 hours and extruded into strips, and then placed in a muffle furnace at a temperature of 10°C/min. The temperature is raised to 600-1000°C at a rate of 600-1000°C, preferably sintering at a constant temperature of 800°C for 4 hours, and the cerium-lanthanum-based desulfurizer is obtained after natural cooling, which is taken out and sealed and dried for storage;

The pore-forming agent is analytically pure amylose with a molecular weight of 1×10 ⁵ -2×10 ⁵ ;

Described bonding agent is chemically pure kaolin, and preferred molecular weight is 258.09 ;

The amount of cerium oxide, lanthanum oxide, pore-forming agent and binder is calculated by mass ratio, that is, cerium oxide: lanthanum oxide: pore-forming agent: binder is 15:4.5-6.5:1-1.5:1 .

The above-mentioned cerium-lanthanum-based desulfurizer can be widely used in IGCC gas desulfurization and purification, and can also be applied to many industrial occasions. It will show a good effect on the emission control of environmental pollutants, and has high promotion value and application prospect.

Beneficial effects of the present invention

A cerium-lanthanum-based desulfurizer of the present invention contains lanthanum oxide and cerium oxide, and lanthanum oxide is a good structural aid, so that the final prepared cerium-lanthanum-based desulfurizer has good thermal stability and can meet more requirements. High calcination temperature requirements. At the same time, cerium oxide and lanthanum oxide form a CeO ₂ -La ₂ O ₃ complex, which promotes the crystal transformation from block to sphere, and the crystal volume increases, so that the final prepared cerium-lanthanum-based desulfurizer has higher desulfurization efficiency.

The final prepared cerium-lanthanum-based desulfurizer of the present invention can be widely used in IGCC coal gas desulfurization and purification because it has good thermal stability and high desulfurization efficiency, and can also be applied to many industrial occasions. The emission control has shown very good effect and has high promotion value and application prospect.

In summary, the cerium-lanthanum-based desulfurizer of the present invention is a new type of composite metal oxide desulfurizer, and its main component, cerium oxide, is known as the second-generation high-temperature desulfurizer, which is improved by adding a certain amount of lanthanum oxide The prepared cerium-lanthanum-based desulfurizer has high desulfurization efficiency. With the continuous improvement of people's requirements for environmental quality, the standards for pollutant discharge are also improving. The cerium-lanthanum-based desulfurizer of the present invention can be well served in high-temperature desulfurization systems, and has great advantages for flue gas desulfurization in power plants and related gas industries. Good effect, high social and economic value, broad market prospect.

Description of drawings

Figure 1. Schematic diagram of the evaluation system for cerium-lanthanum-based desulfurizers;

Fig. 2, the A1-700 sample SEM figure of embodiment 1 gained;

Fig. 3, the A1-800 sample SEM figure of embodiment 2 gained;

Fig. 4, the influence of the A1-700 sample and the A1-800 sample obtained in Examples 1 and 2 on the desulfurization efficiency at different reaction temperatures;

Fig. 5, the B1 sample SEM figure of embodiment 3 gained;

Fig. 6, the B2 sample SEM figure of embodiment 4 gained;

Fig. 7, the influence of B1 and B2 samples obtained in Examples 3 and 4 on the desulfurization efficiency at different reaction temperatures.

Detailed ways

The present invention will be further described below through specific embodiments in conjunction with the accompanying drawings, but the present invention is not limited.

The schematic diagram of the cerium-lanthanum-based desulfurizer evaluation system used in the present invention is shown in Figure 1, including a mixed gas bottle 1, a valve 2, a three-way valve 3, a fixed bed reactor 4, a heating furnace 5, a cooling device 6, and a hydrogen sulfide gas detection Instrument 7 and tail gas treatment tank 8, wherein the fixed bed reactor has an internal diameter D=14mm and a length l=450mm, and a thermocouple is used to control the reaction temperature in the fixed bed;

Its working process is as follows:

First turn on the heating furnace 5, preheat it, and heat it to the required temperature. The simulated IGCC crude gas containing H ₂ S enters the fixed bed reactor 4 from bottom to top to react with the desulfurizer, and then flows into the cooling device 6 to reduce the gas temperature. , there is no reaction between the gas components, and the concentration of hydrogen sulfide in the outlet gas is detected online by a hydrogen sulfide gas detector 7, and the reacted mixed gas enters the tail gas treatment tank.

The desulfurization efficiency is calculated according to formula (1):

                 （1）

(1)

In the formula, η represents the desulfurization efficiency, C _in represents the hydrogen sulfide concentration in the fixed bed reactor inlet gas, and C _out represents the hydrogen sulfide concentration in the fixed bed reactor outlet gas.

When evaluating the cerium-lanthanum-based desulfurizer with the cerium-lanthanum-based desulfurizer evaluation system in each embodiment of the present invention, the gas components used are shown in Table 1.

Table 1 Composition of mixed gas

gas CO H ₂ H ₂ O CO ₂ H ₂ S N2 content 36.35% 27.38% 15.10% 12.48% 2000pm balance gas

Manufacturers and specifications of reagents used in each embodiment of the present invention are as follows:

Cerium oxide: produced by Shanghai Runjie Chemical Reagent Co., Ltd., with a specification of 3.5N and a molecular weight of 172.11;

Lanthanum oxide: produced by Shanghai Runjie Chemical Reagent Co., Ltd., with a specification of 4N and a molecular weight of 325.84;

Starch: produced by Shanghai Abby Chemical Reagent Co., Ltd., the specification is AR, straight chain, molecular weight 1×10 ⁵ -2×10 ⁵ ;

Kaolin: produced by Shanghai Zhanyun Chemical Co., Ltd., specification CP, molecular weight 258.09.

Example 1

A cerium-lanthanum-based desulfurizer, prepared by a method comprising the steps of:

That is, firstly, 30 g of cerium oxide, 12 g of lanthanum oxide, 3 g of pore forming agent, and 2 g of binder are mixed to obtain a powder mixture by dry mixing method;

Then, the obtained powder mixture is mixed with a planetary ball mill, and the obtained ball-milled powder is dried in a vacuum drying oven at a temperature of 150°C for 2 hours and extruded into strips, and then placed in a muffle furnace at a temperature of 10°C/min. Raise the temperature to 700°C for 4 hours at a constant temperature and sinter at a constant temperature. After natural cooling, the cerium-lanthanum-based desulfurizer A1-700 is obtained. Take it out and store it in an airtight and dry place;

The pore-forming agent is analytically pure amylose with a molecular weight of 1×10 ⁵ -2×10 ⁵ ;

The binder is chemically pure kaolin with a molecular weight of 258.09 ;

The amounts of cerium oxide, lanthanum oxide, pore-forming agent and binder are calculated by mass ratio, that is, cerium oxide: lanthanum oxide: pore-forming agent: binder is 15:6:1.5:1.

Example 2

A cerium-lanthanum-based desulfurizer, prepared by a method comprising the steps of:

That is, firstly, 30 g of cerium oxide, 12 g of lanthanum oxide, 3 g of pore forming agent, and 2 g of binder are mixed to obtain a powder mixture by dry mixing method;

Then, the obtained powder mixture is mixed with a planetary ball mill, and the obtained ball-milled powder is dried in a vacuum drying oven at a temperature of 150°C for 2 hours and extruded into strips, and then placed in a muffle furnace at a temperature of 10°C/min. Heat up to 800°C for 4 hours at a constant temperature and sinter at a constant temperature. After natural cooling, the cerium-lanthanum-based desulfurizer A1-800 is obtained. Take it out and store it in a sealed dry place;

The pore-forming agent is analytically pure amylose with a molecular weight of 1×10 ⁵ -2×10 ⁵ ;

The binder is chemically pure kaolin with a molecular weight of 258.09;

The amounts of cerium oxide, lanthanum oxide, pore-forming agent and binder are calculated by mass ratio, that is, cerium oxide: lanthanum oxide: pore-forming agent: binder is 15:6:1.5:1.

The cerium-lanthanum-based desulfurizer A1-700 and cerium-lanthanum-based desulfurizer A1-800 obtained in Examples 1 and 2 were scanned with a JSM-6390LV tungsten filament scanning electron microscope from JEOL Ltd. The resulting SEM images are shown in Figure 2 and Figure 3 As shown, it can be seen from Figure 2 that the A1-700 sample has more concave parts, and from Figure 3 it can be seen that the particle distribution range of the A1-800 sample is small and uniform, and the bright area is stronger than that of the A1-700 sample in Figure 2 It shows that the surface of the crystal protrudes more, so the specific surface area will increase, the pore volume will increase, and the crystal has a tendency to transform from block to granular, which shows that within a certain range, the increase of sintering temperature is beneficial to the cerium Lanthanum-based desulfurizer pore volume increase and crystal phase transformation.

Put the cerium-lanthanum-based desulfurizer A1-700 and cerium-lanthanum-based desulfurizer A1-800 obtained in Examples 1 and 2 in the cerium-lanthanum-based desulfurizer evaluation system, and control the reaction temperature of the fixed-bed reactor to 600°C, 700°C, The desulfurization reaction was carried out at 800°C, 900°C, and 1000°C, and the desulfurization effect was evaluated. The desulfurization effect is shown in Figure 4. It can be seen from Figure 4 that the cerium-lanthanum-based desulfurizer prepared at the sintering temperature of 800°C is relatively sintered at 700°C. The cerium-lanthanum-based desulfurization agent prepared at high temperature has better desulfurization effect, and with the increase of reaction temperature, the desulfurization effect gradually becomes better. The desulfurization effect is reduced instead.

This shows that in the preparation process of the cerium-lanthanum-based desulfurizer of the present invention, the sintering temperature of 800° C. is relatively good, and a higher reaction temperature is beneficial to the improvement of the desulfurization effect, but too high a reaction temperature may cause coking of the cerium-lanthanum-based desulfurizer. leading to a decrease in the desulfurization effect.

Example 3

A cerium-lanthanum-based desulfurizer, prepared by a method comprising the steps of:

That is, firstly, 30 g of cerium oxide, 13 g of lanthanum oxide, 2 g of pore forming agent, and 2 g of adhesive are mixed to obtain a powder mixture by dry mixing method;

Then, the obtained powder mixture is mixed with a planetary ball mill, and the obtained ball-milled powder is dried in a vacuum drying oven at a temperature of 150°C for 2 hours and extruded into strips, and then placed in a muffle furnace at a temperature of 10°C/min. Heat up to 800°C for 4 hours at a constant temperature and sinter at a constant temperature. After natural cooling, the cerium-lanthanum-based desulfurizer B1 is obtained. Take it out and store it in a sealed dry place;

The pore-forming agent is analytically pure amylose with a molecular weight of 1×10 ⁵ -2×10 ⁵ ;

The binder is chemically pure kaolin with a molecular weight of 258.09 ;

The amounts of cerium oxide, lanthanum oxide, pore-forming agent and binder are calculated by mass ratio, that is, cerium oxide: lanthanum oxide: pore-forming agent: binder is 15:6.5:1:1.

Example 4

A cerium-lanthanum-based desulfurizer, prepared by a method comprising the steps of:

That is, firstly, 30 g of cerium oxide, 9 g of lanthanum oxide, 2 g of pore forming agent, and 2 g of adhesive are mixed to obtain a powder mixture by dry mixing method;

Then, the obtained powder mixture is mixed with a planetary ball mill, and the obtained ball-milled powder is dried in a vacuum drying oven at a temperature of 150°C for 2 hours and extruded into strips, and then placed in a muffle furnace at a temperature of 10°C/min. Raise the temperature to 800°C for 4 hours at a constant temperature and sinter at a constant temperature. After natural cooling, the cerium-lanthanum-based desulfurizer B2 is obtained. Take it out and store it in a sealed dry place;

The pore-forming agent is analytically pure amylose with a molecular weight of 1×10 ⁵ -2×10 ⁵ ;

The binder is chemically pure kaolin with a molecular weight of 258.09 ;

The amounts of cerium oxide, lanthanum oxide, pore-forming agent and binder are calculated by mass ratio, that is, cerium oxide: lanthanum oxide: pore-forming agent: binder is 15:4.5:1:1.

The cerium-lanthanum-based desulfurizer B1 and the cerium-lanthanum-based desulfurizer B2 obtained in Examples 3 and 4 are scanned by a scanning electron microscope with a JEOL Ltd. JSM-6390LV tungsten filament, and the resulting SEM images are shown in Figures 5 and 6. From the comparison of Figure 5 and Figure 6, it can be seen that the cerium-lanthanum-based desulfurizer B1 has large spherical crystals, and the volume of the spherical crystals is larger than that of the cerium-lanthanum-based desulfurizer B2. Lanthanum-based desulfurizer B2 is more compact between crystals. This may be due to the formation of CeO ₂ -La ₂ O ₃ complexes between cerium oxide and lanthanum oxide to promote the crystal transformation from block to spherical crystal, and the crystal volume increases. This shows that the increase in the content of lanthanum oxide is conducive to the transformation of desulfurizer crystals into spherical crystals, and the crystal volume increases.

Use the cerium-lanthanum-based desulfurizer B1 and cerium-lanthanum-based desulfurizer B2 obtained in Examples 3 and 4 in the cerium-lanthanum-based desulfurizer evaluation system, and control the reaction temperature of the fixed-bed reactor to 600°C, 700°C, 800°C, and 900°C, respectively. ℃, 1000℃ for desulfurization reaction, and evaluate its desulfurization effect. The desulfurization effect is shown in Figure 7. From Figure 7, it can be seen that the prepared desulfurizer B1 has a higher desulfurization efficiency, and it is also in the reaction at 800 The highest desulfurization effect is achieved at high temperature, which indicates that appropriately increasing the amount of lanthanum oxide is beneficial to improve the desulfurization efficiency of the desulfurizer. Increase in size.

In summary, a cerium-lanthanum-based desulfurizer obtained at a sintering temperature of 800°C according to the present invention has high activity and reaction effect for desulfurization reaction at 800°C, and within a certain range, the lanthanum oxide The increase of the blending amount is beneficial to the improvement of the desulfurization effect of the desulfurizer.

The foregoing is only an example of the embodiment of the present invention. It should be pointed out that for those of ordinary skill in the art, some improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and All modifications should be regarded as the protection scope of the present invention.

Claims (6)

1. a cerium lanthanum base desulfurizer is characterized in that the method preparation as follows of described cerium lanthanum base desulfurizer and obtains:

At first adopt dry mix, cerium oxide, lanthanum trioxide and pore-forming material, caking agent are mixed to get to powder mixture;

Then, adopt planetary ball mill to be mixed the powder mixture of gained, it is dry 2h extruded moulding under 150 ℃ that the ball milling powder of gained is controlled temperature in vacuum drying oven, then it is positioned in retort furnace, the speed of controlling 10 ℃/min is warming up to 600-1000 ℃ of lower constant temperature sintering 4h, obtains cerium lanthanum base desulfurizer after naturally cooling;

Described pore-forming material is that molecular weight is 1 * 10 ⁵-2 * 10 ⁵the analytical pure amylose starch;

Described caking agent is chemical pure kaolin ;

The consumption of described cerium oxide, lanthanum trioxide, pore-forming material and caking agent, calculate in mass ratio, i.e. cerium oxide: lanthanum trioxide: pore-forming material: caking agent is 15:4.5-6.5:1-1.5:1.

2. a kind of cerium lanthanum base desulfurizer as claimed in claim 1, is characterized in that describedly in retort furnace, and the speed of controlling 10 ℃/min is warming up to 800 ℃ of lower constant temperature sintering 4h, obtains cerium lanthanum base desulfurizer after naturally cooling.

3. a kind of cerium lanthanum base desulfurizer as claimed in claim 2, is characterized in that the consumption of described cerium oxide, lanthanum trioxide, pore-forming material and caking agent, and calculate in mass ratio, i.e. cerium oxide: lanthanum trioxide: pore-forming material: caking agent is 15:4.5:1:1.

4. a kind of cerium lanthanum base desulfurizer as claimed in claim 2, is characterized in that the consumption of described cerium oxide, lanthanum trioxide, pore-forming material and caking agent, and calculate in mass ratio, i.e. cerium oxide: lanthanum trioxide: pore-forming material: caking agent is 15:6:1.5:1.

5. a kind of cerium lanthanum base desulfurizer as claimed in claim 2, is characterized in that the consumption of described cerium oxide, lanthanum trioxide, pore-forming material and caking agent, and calculate in mass ratio, i.e. cerium oxide: lanthanum trioxide: pore-forming material: caking agent is 15:6.5:1:1.

6. as claim 3,4 or 5 described a kind of cerium lanthanum base desulfurizers, it is characterized in that described caking agent is the chemical pure kaolin that molecular weight is 258.09.

Images