hydrodewaxing catalyst LH-3881

hydrodewaxing catalyst is a new technology of petroleum refining growing up in the 1970’s. 

hydrodewaxing catalyst is a new technology of petroleum refining growing up in the 1970’s. The basic principle of this technology is by the using of the catalyst which adopts ZSM-5 molecular sieve with special pore path as carrier to split the straight chain or the chain similar to straight chain hydrocarbons into gasoline fraction and a small amount of C3、C4，thus the melting point of the fractions in the rest part can be reduced remarkably. This process can be completed without or with very small amount of hydrogen consumption. So that it can be widely used for reducing the freezing point of kerosene and melting point of diesel, it can also be used in the dewaxing process for lube oil.
FRIPP began to research catalyst 3881 in 1982. In 1988，the enlarged industrial production of this catalyst was carried out successfully by the Catalyst Plant FPC CNPC and then put into regular industrial production. It has received the national patent，the medal of superior item of patent，and the second grade medal of scientific and technology progress from SINOPEC.

The feature of this achievement is that the ZSM-5 molecular sieve is synthesized by a non-amine synthesis technique directly. Therefore this catalyst is of low cost，low initial reaction temperature，and the running period of it is longer than the same kind of imported catalyst. This catalyst also possesses good hydrogen activation and oxygen regeneration property. It can be hydrogen activated and oxygen regenerated repeatedly for several times. It can meet the requirements of dewaxing technology for treating waxy heavy diesel.
(I)、Characteristics of the catalyst

(II)、Activity index

technology condition	pressure MPa	temperature ℃	volume space velocity h-1	hydrogen oil volume ratio
	4.0	*	1.0	420
Feedstock	the blending oil of AGO and light VGO of Shengli crude
activity evaluation	when reaching the initial equilibrium period, reaction temperature keeping steadily for 72 hours continuously, standard reaction temperature ≤380℃ considered as up to standard

* Reaction temperature takes the pour point to control the product diesel fraction at -10℃ as standard.

(III)、Results of industrial running
The dewaxing device of Shengli Refinery of Qilu Petrochemical Corporation was put into producing in 1982, the first batch of catalyst used is the imported ZSM-5 catalyst, after that, in Oct.1986, it began to use the first generation amine type molecular sieve catalyst—catalyst 3862. From Oct. 1988, it adopted catalyst 3881 regularly. The effect of running was fairly good.
From the results of using the first batch of catalyst HT-3881 in the industrial dewaxing device, we can see that in case of the other technology parameters (such as space velocity etc.) are in the same condition the average reaction temperature of both the reactor inlet and bed layer are about 10℃ lower than using imported catalyst, and 15℃ lower than the standard reaction temperature. hydrodewaxing catalyst shows that the activity of catalyst 3881 is rather high. From the yield point of view, we can see that in the initial running period, the total liquid yield of using domestic catalyst or the imported catalyst is about the same. But after hydrogen activated the yield of using the domestic catalyst has the tendency to increase gradually and the main product, diesel, yield is higher than the imported catalyst all along. This shows that the selectivity and stability of this catalyst is also rather high.
A comparison of the results of industrial runs between catalyst HT-3881 and the same kind of the imported catalyst are as following.

stage of production	initial period of operation	before regeneration	initial period scaling of imported catalyst
scaling time	88.10.25	89.9.14
feed	blending oil of AGO and light VGO of Shengli crude