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Research And Development Of Diesel Deep Hydrodesulfurization Catalyst.
Apr 03, 2018

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Catalytic cracking is one of the major process of refinery in China, the catalytic cracking diesel oil with high sulfur, nitrogen and aromatic content, density and poor stability of low cetane number, characteristic, need a high severity depth hydrogenation request [1 ~ 2], is the most difficult machining refinery diesel fraction.

Product upgrade strategy according to the country, on January 1, 2017, the national comprehensive supplier V standard automotive gasoline and diesel, the VI emission standard solicit opinion draft has been released, is expected to reach the 2020 national petrol and diesel Ⅵ emission standards.

With the increase of the quality of crude oil and the deterioration of the quality of crude oil in the world, the characteristics of direct distillation diesel and catalytic cracking diesel are more and more severe, and the requirement of hydrotreating catalyst is higher and higher.

Beijing Ann Nike energy engineering Co., LTD., according to current situation of the market, successfully developed two kinds of hydrofining catalyst: Co - Mo as the main active component of hydrofining catalyst AHT - 33 high desulfurization activity, suitable for high sulfur straight run diesel;

Aht-28, a hydrogenation catalyst with ni-mo as the main active component, has high desulfurization and denitrification activity and aromatics saturation capacity, which is suitable for the treatment of poor catalytic cracking diesel oil.

In this paper, the experimental results of two refining catalysts on hydrogenation of small fixed bed are introduced.

Experiment 1

1) raw material oil

There are two kinds of raw materials used in the experiment: one is the high sulfur straight run diesel oil of a branch of China petroleum chemical co., LTD.

The other is the catalytic cracking diesel of a local refinery in shandong province.

The properties of raw materials are shown in table 1 and table 2.

Test rig

The test device is a small fixed bed hydrogenation device, which is used in a single pass through the process and hydrogen is not recycled.

The schematic diagram of the process is shown in figure 1.


The raw material oil is pumped through the feed oil pump, and then enters the isothermal reactor after mixing with hydrogen at the reactor inlet. The reaction product enters the high pressure separator for oil and gas separation.

The bottom discharge of the high pressure separator enters the sampling bottle under the control of the liquid level of the high pressure separator;

The top gas phase of the high pressure separator enters the water wash tank. After washing, it enters the alkaline cleaning tank under pressure control of the high pressure separator, and the gas is discharged into the vent line after the alkaline cleaning.

Reaction pressure control precision of + / - 0.01 MPa, the reaction temperature control precision of + / - 1 ℃, the hydrogen flow control accuracy + / - 1%, raw material feed rate control accuracy + / - 1 g.

2 results and discussion

The results of hydrofining of direct distillation diesel oil.

The use of co-mo hydrofining catalyst AHT-33 was used for direct distillation of diesel hydrogenation.

The conditions and properties of direct distillation diesel and its hydro-refining process are shown in table 1.

Among them, the cetane index is calculated by astmd44737, and the increase of cetane index is defined as the difference between the product cetane index and the raw material oil cetane index.

As can be seen from table 1, the direct distillation diesel used in this experiment is a typical high sulfur straight run diesel, which is more representative.

During the experiment, the reaction pressure was maintained at 6.0MPa, the hydrogen oil was over 800, and the volume airspeed was 1.5h-1, and the influence of the reaction temperature on HDS and HDN was investigated [3].


According to table 1, the curve of reaction temperature - desulfurization and denitrification rate is shown in figure 2.

The figure 2 shows that in the temperature range, sulfur, nitrogen removal rate increases with reaction temperature, the reaction temperature of 320 ℃ before sulfur, nitrogen removal rate increase fast, when the temperature exceeds 320 ℃ after sulfur, nitrogen removal rate is increasing slowly, the reason for the catalyst good low temperature activity, sulfur and nitrogen removal at low temperature have to a lower level.

Under the condition of the reaction temperature of 340 ℃, product sulfur content reduced to 6.9 mu g/g, the desulfurization rate of 99.94%, diesel density reduces 20 kg/m3, aromatic content by 12%, cetane index is 61.5, and 5.1 units, product quality to meet the V diesel standards.


The results of the catalytic cracking of diesel oil with catalytic cracking.

The aht-28 activity group of catalytic cracking diesel hydrogenation catalyst was divided into Ni-Mo and compared with foreign reference catalyst.

The conditions and properties of catalytic cracking diesel and its hydrogenation are shown in table 2.

The raw material oil of this experiment is a catalytic cracking diesel oil in shandong province, which has high density, nitrogen content and high aromatic content. It is a typical low-quality catalytic cracking diesel oil.

According to table 2, the comparison curves of desulfurization rate and denitrification rate are shown in figure 3 and figure 4.

It can be seen from FIG. 3 and FIG. 4 that the desulfurization activity and denitrification activity of aht-28 are higher than that of foreign reference agents.

Calculate according to the reaction rate equation of two relative desulfurization and denitrification activity of catalysts, can be relatively desulfurization activity of AHT - 28, relatively denitrification activity were higher than reference foreign agent, and under a lower reaction temperature desulfurization and denitrification activity is far higher than reference agent abroad.

At 340 ℃, AHT - 28 desulfurization activity is relatively in foreign reference agent 184%, relative activity of nitrogen is 151% of the foreign reference agent.

As can be seen from table 2, the content of aromatic hydrocarbons in aht-28 is lower than that of foreign reference.

Analysis of product properties in table 2, AHT under 350 ℃ - 28 products 28.4 mu g/g, the desulfurization rate 98.83% sulfur content, nitrogen content of 6.6 mu g/g, the denitrification rate was 99.30%, 50% aromatic content, was reduced by 18%, cetane index of 33.4, 5.4 units.

Because of the low reaction pressure, difficult to removal push wood is a small amount of the most difficult removal of diphenyl and thiophene sulfide, sulfur content is difficult to achieve the five standards, but the overall performance has reached the international leading level.

To sum up, aht-28 is higher than foreign reference agent for desulfurization, denitrification and aromatic saturation of catalytic cracking diesel.

AHT - 28 is a kind of high desulfurization, denitrogenation and aromatics saturation capacity of hydrofining catalyst, is suitable for the depth of the catalytic cracking diesel oil hydrotreating, hydrocracking modification/hydrofining of hydrocracking catalyst.



3 conclusion

(1) to a Co - Mo as active component of hydrofining catalyst AHT - 33 of high hydrogenation desulfurization activity, can deal with 1.09 w % of high sulfur content in straight run diesel, the desulfurization rate was 99.94%, and the product sulfur content of 6.9 mu g/g, can satisfy the V standard, cetane index increased 5.1 units at the same time.

(2) with Ni - Mo as active component of hydrofining catalyst AHT - 28 has the very high hydrogenation desulfurization, denitrogenation and aromatics saturation activity, desulfurization activity is 126% of the foreign reference agent, denitrification activity is 125% of the foreign reference agent, product 5.4 unit higher cetane index, can be used in the depth of the catalytic cracking diesel oil hydrotreating, hydrocracking modification and hydrofining hydrocracking unit of raw materials (reference).

Original title: research and development of diesel deep hydrodesulfurization catalyst.