Isomerization Dewaxing Catalyst Life Extension
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Solution Overview
Problem
Isomerization dewaxing of hydrocarbon oils results in hydrocarbon cracking, leading to reduced catalyst life and increased costs due to the dual functionality of hydroisomerization catalysts, which complicates the production of lubricant base oils with improved cold flow properties.
Innovation Solution
A method involving two steps in isomerization dewaxing: the first step suppresses hydrocarbon cracking to extend catalyst life, and the second step temporarily increases cracking rates to eliminate drift and enhance catalyst longevity, using a hydroisomerization catalyst with a zeolite structure and platinum/palladium support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If isomerization dewaxing is carried out using a hydroisomerization catalyst, then cold flow property is improved, but catalyst life is reduced due to hydrocarbon cracking
Solution Approach 1:
The continuous isomerization dewaxing process is segmented into two distinct operational steps: a first step operating at lower cracking rates (10 mass % or less) to maintain catalyst life, and a second step operating at higher cracking rates (13 mass % or more) to eliminate drift and extend catalyst life. This segmentation allows each step to optimize for its specific function while working together to resolve the contradiction between improving cold flow properties and extending catalyst life.
Solution Approach 2:
The invention implements periodic switching between two operational modes: normally operating in the first step with controlled cracking to preserve catalyst life, and temporarily switching to the second step with higher cracking rates to eliminate drift. This periodic action between two distinct operational states allows the system to achieve both extended catalyst life and improved cold flow properties.
2Duration of action of stationary object
If cracking rate is increased to eliminate drift, then catalyst life is extended, but product yield is reduced
Solution Approach 1:
The invention applies partial excessive action by temporarily increasing the cracking rate to 13 mass % or more in the second step, which is higher than the normal operating level of 10 mass % or less. This temporary excessive cracking action is sufficient to eliminate drift and extend catalyst life, after which the system returns to normal operation, thus achieving the beneficial effect without permanently sacrificing product yield.
Solution Approach 2:
The system periodically switches between normal operation (first step with cracking rate ≤10 mass %) and drift elimination mode (second step with cracking rate ≥13 mass %). This periodic action allows temporary acceptance of reduced product yield during the second step in exchange for extended catalyst life, while maintaining overall productivity through return to normal operation.
3Quantity of substance
If cracking rate is suppressed to maintain product yield, then product yield is improved, but catalyst drift occurs reducing catalyst life
Solution Approach 1:
The invention implements preliminary action by periodically performing the second step with higher cracking rates before catalyst drift becomes severe. This preliminary drift elimination action prevents catalyst deactivation and extends catalyst life, allowing the system to maintain normal operation with suppressed cracking rates for extended periods while preserving both product yield and catalyst life.
Solution Approach 2:
The system employs periodic switching between normal operation mode (suppressing cracking to maintain product yield) and drift elimination mode (increasing cracking to extend catalyst life). This periodic action resolves the contradiction by accepting temporary reduction in product yield during the second step in exchange for significantly extended catalyst life between cycles.
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
This approach extends the life of hydroisomerization catalysts and stabilizes the production of lubricant base oils with improved cold flow properties by managing cracking rates and catalyst activity.
Implementation Method 1
hydroisomerization catalysts having bifunction capable of hydrogenation-dehydrogenation and isomerization
Implementation Method 2
isomerizing normal paraffins in the hydrocarbon oil to isoparaffins
Implementation Method 3
the hydrocarbon oil cracking (conversion to a lighter product) also proceeds at the time of isomerization dewaxing
Data Source
AI summary
A method for producing a lubricant base oil which comprises a first step of carrying out isomerization dewaxing by contacting, in the presence of hydrogen, a hydrocarbon oil containing normal paraffin having a boiling point of 360° C. or higher, with a hydroisomerization catalyst under conditions such that a cracking rate defined in the following formula (1) is 10 mass % or less, and a second step of carrying out the above isomerization dewaxing by temporarily switching the above conditions to conditions such that the cracking rate is 13 mass % or more.Cracking rate (mass %)=[(C1−C2)/C1]×100 (1)wherein C1 represents the mass ratio of a fraction having a boiling point of 360° C. or higher in the above hydrocarbon oil, and C2 represents the mass ratio of the fraction having a boiling point of 360° C. or higher in the above hydrocarbon oil after the isomerization dewaxing.