(384f) The Shown Stirring Effect Observed in the (FAU structure) X Zeolite Synthesis with Carbon Nanoparticles Occluded

The shown stirring effect
observed in the (FAU structure) X zeolite synthesis with carbon nanoparticles
occluded.

Zeolites have found wide application as
heterogeneous catalysts, particularly in refineries and petrochemicals.
However, in many applications, a problem encountered is that the zeolites has
only micropores, which imposes diffusion limitations on the molecules of
reactants and products. One of the most widely employed zeolites in refineries
and mainly in fluid catalytic cracking process is the Y zeolite. Some great
depths oil fields has shown an increase in the size of its molecules, making
difficult its processing with existing zeolitic industrial catalysts. Oil
refiners have been spent research efforts of other zeolites with bigger microporous
and mesoporous material. An example is the Beta zeolite, which has larger pores
than the traditional zeolite Y, but it's hard to be synthetized. Thus, the
synthesis of mesoporous zeolites aims to increase accessibility to active sites
by reducing the restrictions of molecules of reactants and products in the bulk
of the catalyst.

In order to determine the variables that had the
more influence on the FAU X zeolite synthesis with low SiO2/Al2O3, the
Plackett-Burman statistical method was used. The selected variables were
impeller type and speed, mixing time, order of reagent addition , stirring
time, ageing time in low temperature, crystallization time and presence of
crystal seeds.

We opted for conducting 12 experiments,
including 3 fictitious variables. These fictitious variables should present low
influence in the procedure. The levels for each variable were delimited
adopting the higher levels for the lower and higher values for minors see Table
1.

Table 1: Ramdomly selected variables for Plackett-Burman
method

Following the implementation of the method,
Table 2, presents the order distribution of the variables and the respective
levels to be used in the numbered experiments.

 Table 2: Distribution of levels depending on the
variables for each experiment.

After the elaboration of the planning, the
twelve experiments variables were carried out using a common methodology. The
adsorption of toluene of the twelve samples were determined in a dissector
where the silica gel has been replaced with a solution of vaseline and toluene.
The samples were weighted during 20 days up to constant weight (Figure 1).
According to the adsorption measurements (Table 3) samples 1, 2, 3, 6, 9 and 11
presented better adsorption of toluene.

Figure 1 - Toluene adsorption for Sample 9

Table 3
- Toluene adsorption measurement

Based on a hypothesis test we concluded that the
variables that shown more influence on adsorption capacity were stirring time
(higher is better), mixing time (lower is better), crystallization time
(largest effect), impeller type (toothed disperser is better) and the presence
of seeds. One dummy variable presented a large effect, which means that
possibly it has confused with other studied variables.

According to this study, the samples that
presented high toluene adsorption capacity were crystallized with 24 h, with a
mixing time lower than one minute, with a stirring time of 5 minutes using the
toothed disperser and seeds of FAU X zeolite.

Powder diffraction X-ray has shown pure
crystalline FAU X zeolite for all samples that presented high toluene adsorption
capacity, which means validate the utilized methodology.

In the next step of this study treated carbon
nanoparticle will be included in the synthesis batches to verify if they
get occluded in crystal zeolites, making possible to obtain mesoporous
materials useful for heavy oil cracking.

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