CN116493023A

CN116493023A - Tail gas catalyst for gasoline generating set and preparation method thereof

Info

Publication number: CN116493023A
Application number: CN202310466141.1A
Authority: CN
Inventors: 浦琦伟; 孙亮; 王卫东; 岳军; 张云; 刘杰; 贾莉伟; 王燕; 马承艺
Original assignee: Wuxi Weifu Environmental Protection Catalyst Co Ltd
Current assignee: Wuxi Weifu Environmental Protection Catalyst Co Ltd
Priority date: 2023-04-27
Filing date: 2023-04-27
Publication date: 2023-07-28

Abstract

The invention relates to a gasoline generator set tail gas catalyst and a preparation method thereof. The preparation method comprises the following steps: weighing cerium nitrate hydrate capable of theoretically generating 50-70 g of cerium oxide, adding the cerium nitrate hydrate into deionized water, and regulating pH by using carboxylic acid to obtain a mixed solution; weighing ferric nitrate hydrate capable of theoretically generating 5-20 g of ferric oxide, adding the ferric nitrate hydrate into deionized water, and dripping a platinum nitrate solution capable of theoretically generating 0.1-2 g of platinum oxide to obtain a mixed solution; mixing the two mixed solutions, regulating the pH with ammonia water, and adding alcohol compounds; drying and roasting the mixed slurry, and then crushing and ball-milling to obtain finished slurry; and (3) coating the slurry on a carrier, and drying and roasting to obtain the catalyst. The catalyst disclosed by the invention has the advantages of simple preparation process, high CO conversion rate, good high-temperature resistance and long service life, and is prepared by only adopting noble metal Pt as a catalytic active component, so that the preparation cost is low.

Description

Tail gas catalyst for gasoline generating set and preparation method thereof

Technical Field

The invention belongs to the technical field of catalytic materials for air purification, and particularly relates to a tail gas catalyst of a gasoline generating set and a preparation method thereof.

Background

The gasoline generator set is a device for converting the heat energy of fuel (gasoline) into mechanical energy and driving a generator to convert the mechanical energy into electric energy. When the engine works, air and fuel are mixed into mixed gas by the air inlet mechanism and then enter the combustion chamber to do combustion work and then are discharged. The tail gas discharged by the generator set using gasoline as fuel is basically composed of CO, HC and NO _x The composition is mostly a partial concentrated atmosphere (lambda<1). The U.S. safety regulations for gasoline generating sets in the export united states, beginning at month 4 of 2023, have increased the emission requirement of CO (UL 2201), which must be less than 150g/h and require 500 hours of endurance testing. According to the current condition of the gasoline generating set, the carburetor is basically adopted, the emission amount of CO is 1500-3000 g/h, and if the safety regulation of the gasoline generating set in the United states is required to be achieved, the conversion rate of CO is at least more than 95%.

The Chinese patent No. 2007101602554 provides a method for treating tail gas of a gasoline generating set, but only provides noble metal content, contains three noble metals of Pt, pd and Rh, and does not provide a specific preparation method of a catalyst. The Chinese patent No. 2020102961920 provides a method and a device for treating the tail gas of a gasoline generating set, which have the advantages of higher cleaning degree, convenient disassembly, cleaning, monitoring and observation, and capability of judging whether the tail gas reaches the standard after being treated. But also does not relate to specific catalyst preparation techniques.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide a gasoline generator set tail gas catalyst with high CO conversion rate, good high temperature resistance and long service life and a preparation method thereof.

According to the technical scheme provided by the invention, the tail gas catalyst of the gasoline generating set comprises a metal honeycomb carrier and a catalyst positioned on the metal honeycomb carrier, wherein in the catalyst, the content of cerium oxide is 50-70 g/L, the content of ferric oxide is 5-20 g/L, and the content of platinum oxide is 0.5-2 g/L.

The preparation method of the tail gas catalyst of the gasoline generating set comprises the following steps:

(1) Weighing cerium nitrate hydrate capable of theoretically generating 50-70 g of cerium oxide, adding the cerium nitrate hydrate into deionized water, stirring for 0.5-2 h, regulating pH value to be 2-4 by using carboxylic acid, and stirring for 2-10 h to obtain a mixed solution for later use;

(2) Weighing ferric nitrate hydrate capable of theoretically generating 5-20 g of ferric oxide, adding the ferric nitrate hydrate into deionized water, stirring for 0.5-2 h, slowly dripping a platinum nitrate solution capable of theoretically generating 0.1-2 g of platinum oxide, and continuously stirring for 0.5-2 h to obtain a mixed solution;

(3) Slowly dripping the mixed solution obtained in the step (2) into the mixed solution obtained in the step (1), stirring for 0.5-2 h, adjusting the pH value to be 7-7.5 by ammonia water, stirring for 2-10 h, then adding an alcohol compound, and continuously stirring for 2-10 h to obtain mixed slurry;

(4) Drying the mixed slurry in the step (3) at 60-80 ℃ for 4-10 h, drying at 120-150 ℃ for 4-10 h, roasting at 400-600 ℃ for 2-10 h to obtain Pt-containing catalyst powder, crushing, adding deionized water, and ball milling to obtain Pt-containing finished slurry;

(5) And (3) coating the finished slurry obtained in the step (4) on a metal honeycomb carrier, drying the metal honeycomb carrier for 0.5 to 20 hours at the temperature of 80 to 200 ℃, and roasting the dried carrier for 0.5 to 20 hours at the temperature of 400 to 600 ℃ to obtain the tail gas catalyst of the gasoline generating set.

Preferably, in the step (1), the carboxylic acid is one or more of formic acid, acetic acid, oxalic acid, propionic acid and malonic acid.

Preferably, in the step (3), the alcohol compound is one or more of methanol, ethanol, ethylene glycol, propanol, propylene glycol and glycerol.

The catalyst disclosed by the invention has the advantages of simple preparation process, high CO conversion rate, good high-temperature resistance and long service life, and is prepared by only adopting noble metal Pt as a catalytic active component, so that the preparation cost is low. The cerium oxide is used as a carrier for loading noble metal Pt and base metal Fe, so that the oxygen concentration in the oxidation reaction can be increased, the catalytic oxidation capacity of Pt can be improved, and the high-temperature aging resistance of Pt can be increased; the addition of Fe can further improve the conversion efficiency of CO.

Detailed Description

The invention will be further illustrated with reference to specific examples.

Example 1

(1) Weighing cerium nitrate hydrate capable of theoretically generating 70g of cerium oxide, adding 0.2L of deionized water, stirring for 1h, dropwise adding acetic acid into a cerium nitrate aqueous solution, adjusting the pH value of the solution to be 3, and stirring for 2h to obtain a mixed solution for later use;

(2) Weighing ferric nitrate hydrate capable of theoretically generating 5g of ferric oxide, adding 0.1L of deionized water, stirring for 1h, slowly dripping a platinum nitrate solution capable of theoretically generating 0.5g of platinum oxide, and stirring for 1h to obtain a mixed solution;

(3) Slowly adding the mixed solution prepared in the step (2) into the mixed solution prepared in the step (1), and stirring for 1h; dropwise adding ammonia water, adjusting the pH to be 7.2, and stirring for 2h; weighing 10g of ethylene glycol, slowly adding into the mixed slurry, and continuously stirring for 2 hours to obtain the mixed slurry;

(4) Drying the mixed slurry obtained in the step (3) at 70 ℃ for 10 hours, drying the mixed slurry at 150 ℃ for 10 hours, roasting the mixed slurry at 500 ℃ for 2 hours, crushing the mixed slurry after roasting, and adding 100g of deionized water for ball milling to obtain finished slurry;

(5) And (3) coating the finished slurry obtained after ball milling in the step (4) on a metal carrier with the specification of phi 80 x 60 x 50/300cpsi according to the coating amount of 75.5g/L, drying at 150 ℃ for 4 hours, and roasting at 450 ℃ for 2 hours to obtain the tail gas catalyst of the generator set.

The catalyst obtained in example 1 had a cerium oxide content of 70g/L, an iron oxide content of 5g/L and a platinum oxide content of 0.5g/L.

Example 2

(1) Weighing cerium nitrate hydrate capable of theoretically generating 60g of cerium oxide, adding 0.2L of deionized water, stirring for 0.5h, dropwise adding oxalic acid into a cerium nitrate aqueous solution, adjusting the pH value of the solution to be=3, and stirring for 2h to obtain a mixed solution for later use;

(2) Weighing ferric nitrate hydrate capable of theoretically generating 10g of ferric oxide, adding 0.1L of deionized water, stirring for 1h, slowly dripping a platinum nitrate solution capable of theoretically generating 0.5g of platinum oxide, and stirring for 1h to obtain a mixed solution;

(3) Slowly adding the mixed solution prepared in the step (2) into the mixed solution prepared in the step (1), and stirring for 1h; dropwise adding ammonia water, adjusting the pH to be 7.5, and stirring for 5 hours; weighing 10g of propylene glycol, slowly adding the propylene glycol into the mixed slurry, and continuously stirring for 5 hours to obtain the mixed slurry;

(4) Drying the mixed slurry obtained in the step (3) at 60 ℃ for 10 hours, drying the mixed slurry at 120 ℃ for 10 hours, roasting the mixed slurry at 400 ℃ for 10 hours, crushing the mixed slurry after roasting, and adding 100g of deionized water for ball milling to obtain finished slurry;

(5) And (3) coating the finished slurry obtained after ball milling in the step (4) on a metal carrier with the specification of phi 80 x 60 x 50/300cpsi according to the coating amount of 70.5g/L, drying at 150 ℃ for 4 hours, and roasting at 450 ℃ for 2 hours to obtain the tail gas catalyst of the generator set.

The catalyst obtained in example 2 had a cerium oxide content of 60g/L, an iron oxide content of 10g/L and a platinum oxide content of 0.5g/L.

Example 3

(1) Weighing cerium nitrate hydrate capable of theoretically generating 50g of cerium oxide, adding 0.2L of deionized water, stirring for 2 hours, dropwise adding formic acid into a cerium nitrate aqueous solution, adjusting the pH value of the solution to be 2, and stirring for 6 hours to obtain a mixed solution for later use;

(2) Weighing ferric nitrate hydrate capable of theoretically generating 20g of ferric oxide, adding 0.1L of deionized water, stirring for 2 hours, slowly dripping a platinum nitrate solution capable of theoretically generating 0.5g of platinum oxide, and stirring for 2 hours to obtain a mixed solution;

(3) Slowly adding the mixed solution prepared in the step (2) into the mixed solution prepared in the step (1), and stirring for 0.5h; dropwise adding ammonia water, adjusting the pH to be 7, and stirring for 8 hours; weighing 10g of methanol, slowly adding the methanol into the mixed slurry, and continuously stirring for 8 hours to obtain the mixed slurry;

(4) Drying the mixed slurry obtained in the step (3) at 80 ℃ for 4 hours, drying the mixed slurry at 150 ℃ for 4 hours, roasting the mixed slurry at 600 ℃ for 2 hours, crushing the mixed slurry after roasting, and adding 100g of deionized water for ball milling to obtain finished slurry;

(5) And (3) coating the finished slurry obtained after ball milling in the step (4) on a metal carrier with the specification of phi 80 x 60 x 50/300cpsi according to the coating amount of 70.5g/L, drying at 80 ℃ for 20h, and roasting at 400 ℃ for 20h to obtain the tail gas catalyst of the generator set.

The catalyst obtained in example 3 had a cerium oxide content of 50g/L, an iron oxide content of 20g/L and a platinum oxide content of 0.5g/L.

Example 4

(1) Weighing cerium nitrate hydrate capable of theoretically generating 70g of cerium oxide, adding 0.2L of deionized water, stirring for 1h, dropwise adding propionic acid into cerium nitrate aqueous solution, adjusting the pH value of the solution to be 4, and stirring for 10h to obtain a mixed solution for later use;

(2) Weighing ferric nitrate hydrate capable of theoretically generating 5g of ferric oxide, adding 0.1L of deionized water, stirring for 0.5h, slowly dripping a platinum nitrate solution capable of theoretically generating 1.0g of platinum oxide, and stirring for 0.5h to obtain a mixed solution;

(3) Slowly adding the mixed solution prepared in the step (2) into the mixed solution prepared in the step (1), and stirring for 2 hours; dropwise adding ammonia water, adjusting the pH to be 7, and stirring for 10 hours; weighing 10g of propanol, slowly adding the propanol into the mixed slurry, and continuously stirring for 10 hours to obtain the mixed slurry;

(5) And (3) coating the finished slurry obtained after ball milling in the step (4) on a metal carrier with the specification of phi 80 x 60 x 50/300cpsi according to the coating amount of 76.0g/L, drying at 200 ℃ for 0.5h, and roasting at 600 ℃ for 0.5h to obtain the generator set tail gas catalyst.

The catalyst obtained in example 4 had a cerium oxide content of 70g/L, an iron oxide content of 5g/L and a platinum oxide content of 1.0g/L.

Comparative example 1

(1) Weighing 70g of cerium oxide powder, adding 150g of deionized water, stirring for 2 hours, and performing ball milling;

(2) And (3) coating the slurry subjected to ball milling in the step (1) on a metal carrier with the specification of phi 80 x 60 x 50/300cpsi according to the coating amount of 71g/L, drying at 150 ℃ for 4h, and roasting at 450 ℃ for 2h to obtain the generator set tail gas catalyst.

Comparative example 2

(1) Weighing 70g of gamma-alumina powder, adding 150g of deionized water, stirring for 2 hours, and performing ball milling;

The generator set exhaust catalysts obtained in example 1, example 2, example 3, example 4 and comparative example 1 and comparative example 2 were subjected to a 0h exhaust emission test on a gasoline generator set with a discharge capacity of 420cc and a power of 8.8kw, the test cycle was performed by a six-condition method, and the exhaust tests after 500h of endurance were respectively performed, and the test results are shown in table 1.

TABLE 1

	Emission value of 0h-CO (g/h)	Durable 500h-CO emission value (g/h)
			Example 1	80.8	125.7
Example 2	75.3	120.4
			Example 3	66.4	121.5
Example 4	50.4	71.3
			Comparative example 1	90.7	175.4
Comparative example 2	99.6	153.3

From the test data in Table 1, it can be seen that the noble metal Pt content is the same in examples 1-3, the increase in the amount of ferric oxide improves CO emissions for 0h, and the emission value after 500h durability is substantially similar, but still meets the emission standard of UL 2201; the catalyst of example 4 exhibited good catalytic oxidation performance due to the increased noble metal Pt content, both 0h and 500h durability. The noble metal Pt content in comparative example 1 and comparative example 2 was the same as in example 4, but CO emissions of 0h have exhibited relative disadvantages, and the CO emission value after 500h durability has exceeded the limit of UL2201 regulations.

Claims

1. A kind of petrol generator set tail gas catalyst, characterized by: the catalyst comprises a metal honeycomb carrier and a catalyst positioned on the metal honeycomb carrier, wherein in the catalyst, the content of cerium oxide is 50-70 g/L, the content of ferric oxide is 5-20 g/L, and the content of platinum oxide is 0.5-2 g/L.

2. The method for preparing the tail gas catalyst of the gasoline generating set, which is characterized by comprising the following steps:

(1) Weighing cerium nitrate hydrate capable of theoretically generating 50-70 g of cerium oxide, adding the cerium nitrate hydrate into deionized water, stirring for 0.5-2 hours, adjusting pH=2-4 by using carboxylic acid, and stirring for 2-10 hours to obtain a mixed solution for later use;

(4) Drying the mixed slurry obtained in the step (3) at 60-80 ℃ for 4-10 hours, drying the mixed slurry at 120-150 ℃ for 4-10 hours, roasting the mixed slurry at 400-600 ℃ for 2-10 hours to obtain catalyst powder containing Pt, crushing the catalyst powder, adding deionized water, and ball milling the crushed catalyst powder to obtain finished slurry containing Pt;

(5) And (3) coating the finished slurry obtained in the step (4) on a metal honeycomb carrier, drying the metal honeycomb carrier at 80-200 ℃ for 0.5-20 h, and roasting the dried carrier at 400-600 ℃ for 0.5-20 h to obtain the tail gas catalyst of the gasoline generator set.

3. The method for preparing the tail gas catalyst of the gasoline generating set, according to claim 2, is characterized in that: in the step (1), the carboxylic acid is one or more of formic acid, acetic acid, oxalic acid, propionic acid and malonic acid.

4. The method for preparing the tail gas catalyst of the gasoline generating set, according to claim 2, is characterized in that: in the step (3), the alcohol compound is one or more of methanol, ethanol, glycol, propanol, propylene glycol and glycerol.