ZSM-22 Zeolite Catalyst for Hydroisomerization Selectivity
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Solution Overview
Problem
Current hydroisomerization catalysts face challenges in achieving high isomerization selectivity, leading to inefficient production of lubricant base oils with desired properties such as high viscosity index and low pour point, due to cracking activity and limited applicability of feedstocks.
Innovation Solution
A hydroisomerization catalyst is produced using a ZSM-22 zeolite with a specific method involving ion-exchange and calcination steps, incorporating platinum or palladium, and a binder like silica or alumina, to moderate the elimination of organic templates and inhibit aluminum denaturation, thereby enhancing isomerization selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional bifunctional catalysts are used for catalytic dewaxing to improve fluidity, then normal paraffins are converted to isoparaffins, but hydrocarbon cracking occurs leading to lightening of the hydrocarbon oil and reduced yield of desired fractions
Solution Approach 1:
The catalyst design applies local quality by creating specific acid sites within the zeolite structure that favor isomerization over cracking. The ZSM-22 zeolite with its specific pore structure and aluminum distribution provides localized catalytic properties that selectively promote normal paraffin isomerization while minimizing cracking reactions.
Solution Approach 2:
The invention changes key parameters of the catalyst including the type of zeolite (ZSM-22), the metal component (group 8-10 or group 6), and the preparation method (ion-exchange followed by controlled calcination). These parameter changes optimize the catalyst to achieve high isomerization activity with suppressed cracking, thereby improving both fluidity and yield.
2Temperature
If the degree of conversion of normal paraffins is increased to produce high-quality lubricant base oil with low pour point, then fluidity improves, but lightening of hydrocarbon oil develops making efficient production difficult
Solution Approach 1:
The catalyst is prepared in advance through ion-exchange and controlled calcination to establish the optimal structure before use. This preliminary preparation ensures that the catalyst has the right properties to achieve high conversion of normal paraffins to isoparaffins without excessive cracking, enabling efficient production of low pour point lubricant base oil.
Solution Approach 2:
The invention uses composite materials combining zeolite (ZSM-22) with metal components (group 8-10 or group 6 metals). This composite structure provides both the acid catalysis needed for isomerization and the metal sites that suppress cracking, allowing high conversion to isoparaffins while maintaining productivity.
3Stability of the object's composition
If conventional catalyst preparation methods are used with high calcination temperatures to eliminate organic templates, then template elimination is complete, but aluminum denaturation occurs reducing isomerization selectivity
Solution Approach 1:
The invention changes the calcination temperature parameter from conventional high temperatures to a controlled range of 350-450°C. This parameter change is sufficient to eliminate organic templates while preventing aluminum denaturation in the zeolite structure, thereby maintaining high isomerization selectivity.
Solution Approach 2:
Ion-exchange is performed as a preliminary action before calcination to replace organic templates with ammonium ions. This preliminary step facilitates subsequent low-temperature calcination that can remove templates without requiring high temperatures that would cause aluminum denaturation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method results in a catalyst with improved isomerization selectivity, allowing for efficient conversion of normal paraffins to isoparaffins, thereby producing lubricant base oils with enhanced fluidity and stability at low temperatures with high yield.
Implementation Method 1
ion-exchanging an organic template-containing zeolite which contains an organic template and has a one-dimensional pore structure including a 10-membered ring in a solution containing ammonium ions and/or protons
Implementation Method 2
calcining a catalyst precursor, the catalyst precursor being prepared based on the support precursor including a platinum salt and/or a palladium salt, at a temperature of 350 to 400° C. in an atmosphere containing molecular oxygen
Implementation Method 3
the hydroisomerization catalyst containing a support which includes a zeolite and carries platinum and/or palladium
Implementation Method 4
catalytic dewaxing has been known, for example, in which hydrocarbon oil is contacted with a catalyst known as a bifunctional catalyst, which has a hydrogenation-dehydrogenation function and an isomerization function, in the presence of hydrogen to isomerize normal paraffin contained in hydrocarbon into isoparaffin
Data Source
AI summary
A method for producing a hydroisomerization catalyst includes a first step of preparing a support precursor by heating a mixture containing an ion-exchanged zeolite and a binder, the ion-exchanged zeolite being prepared by ion-exchanging an organic template-containing zeolite which contains an organic template and has a one-dimensional pore structure including a 10-membered ring in a solution containing ammonium ions and/or protons, at a temperature of 250 to 350° C. under N2 atmosphere, and a second step of preparing a hydroisomerization catalyst, which is prepared by calcining a catalyst precursor, the catalyst precursor being prepared based on the support precursor containing a platinum salt and/or a palladium salt, at a temperature of 350 to 400° C. in an atmosphere containing molecular oxygen, the hydroisomerization catalyst containing a support which includes a zeolite and carries platinum and/or palladium.