HydrorefiningcatalyzerIt is composed of active ingredients, adjuvants, and carriers. Its function is to remove sulfur, nitrogen, oxygen, and heavy metals through hydrogenation, as well as to saturate polycyclic aromatic hydrocarbons through hydrogenation. The molecular structure of the raw materials in this process does not undergo significant changes, and may be accompanied by hydrocracking reactions according to various needs. However, the conversion depth is not deep, and the conversion rate is generally around 10%. Hydrorefining catalysts require dual functions of hydrogenation and hydrogenolysis, and the acidity required for hydrogenolysis is not high.

working principle

The mechanism of catalytic hydrogenation (changing the reaction pathway and reducing activation energy): Hydrogen molecules adsorbed on the catalyst generate active hydrogen atoms, which react with alkenes and alkynes whose bonds are weakened by the catalyst.

(1) The more alkyl groups on the double bond carbon atom, the lower the hydrogenation heat, and the more stable the olefin: R2C=CR2 > R2C=CHR > R2C=CH2 > RCH=CH2 > CH2=CH2

(2) Trans isomer is more stable than cis isomer

(3) The hydrogenation heat of acetylene is -313.8 kJ · mol-1, which is twice as high as that of ethylene (-274.4 kJ · mol-1), so the stability of acetylene is lower than that of ethylene.

application

In the presence of catalysts such as Pt, Pd, Ni, etc., alkenes and alkynes undergo addition reactions with hydrogen to produce corresponding alkanes and release heat, which is called the heat of hydrogenation (heat released when 1 mol of unsaturated hydrocarbon is hydrogenated). The mechanism of catalytic hydrogenation (changing the reaction pathway and reducing activation energy): Hydrogen molecules adsorbed on the catalyst generate active hydrogen atoms, which react with alkenes and alkynes whose bonds are weakened by the catalyst.

classification

1. Hydrocracking catalyst

Hydrocracking catalyst is a catalyst used in the hydrocracking process of petroleum refining, where heavy oil undergoes hydrocracking reaction at high temperature of 360-450 ℃ and high pressure of 15-18MPa, and is converted into gas, gasoline, jet fuel, diesel and other products. The hydrocracking process belongs to the secondary processing in petroleum refining, and the processing raw materials are heavy distillate oil, which can also be atmospheric residue oil and vacuum residue oil. The main feature of the hydrocracking process is its high production flexibility, and the distribution of products can be controlled by operating conditions. It can produce gasoline, low freezing point jet fuel and diesel, and can also produce a large amount of tail oil as cracking raw material or lubricating oil. The obtained product has good stability, but the octane rating of gasoline is not high,. Due to harsh operating conditions, high equipment investment and operating costs, the application is not as widespread as catalytic cracking. But the hydrocracking process can process raw materials with high sulfur and aromatic content, and the raw materials undergo strict refinement in the hydrogenation refining reactor before entering the cracking reactor. The feed to the cracking reactor can be recycled oil or not, depending on the target product. The range of circulating oil is very wide, which can be all fractions below gasoline or below diesel（>350 ℃) heavy distillate oil. Most raw materials can be processed using a fixed bed reactor, but residual oil hydrocracking must use a fluidized bed reactor, and the hydrocracking catalyst must adapt to the corresponding raw materials, reaction conditions, and equipment.

2. Hydrorefining catalyst

Hydrorefining catalyst is a catalyst used to remove sulfur and nitrogen compounds from oil products and convert aromatic hydrocarbons into cycloalkanes. The active components are composite oxides or sulfides of metals such as key, diamond, tungsten, phosphorus, etc.

Selection Guide The following factors need to be considered:

(1) Activity

(2) Selective

(3) Stability

(4) Mechanical strength

(5) Regeneration performance

(6) Security

(7) Cost effectiveness ratio

In addition, it is necessary to consider the type and composition properties of the active pharmaceutical ingredient, the quality and distribution requirements of the target product, the hydrogenation process, pressure rating, hydrogen oil volume ratio, and volumetric air velocity.

Determine suitable catalysts and optimal process conditions, while meeting product quality and distribution requirements, to minimize and control side reactions, reduce hydrogen consumption, and improve economic efficiency.

matters needing attention

Do not roll the catalyst on the ground during transportation to prevent it from crushing.

Open the catalyst barrel and leave 10ml of sample in each barrel. Mix and analyze the catalyst.

After opening the barrel, decide whether to sieve based on the condition of the catalyst.

The catalyst must be loaded according to the design height.

The catalyst must be poured into the loading hopper and loaded into the reactor using canvas bags. When handling the catalyst, it should be handled gently and iron drums should not be rolled.

Personnel participating in the loading process must strictly guard against bringing other items into the reactor, such as keys, knives, iron wires, and lead wires.

Personnel entering the reactor must obtain a certificate and wear dust masks.

Before entering the reactor, sample and analyze the gas inside the reactor. If it is qualified, it is allowed to enter the reactor. The reactor must be isolated from the system with blind plates.