Hydroprocessing Renewable Diesel with Zeolitic Catalyst
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Solution Overview
Problem
Current processes for converting renewable sources into gas oil fuels face challenges such as high hydrogen consumption, reduced diesel yields, and environmental concerns like CO2 emissions, with existing methods either increasing NOx emissions or requiring costly hydrogen for hydrodeoxygenation.
Innovation Solution
A continuous process involving hydrotreatment followed by hydroisomerization, using specific catalysts and operating conditions to maximize diesel yields while minimizing hydrogen consumption, and incorporating a thioresistant catalyst to handle sulfur impurities without intermediate gas-liquid separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If transesterification is used to convert vegetable oils, then the chemical structure is transformed into esters, but NOx emissions increase and boiling temperature becomes too high
Solution Approach 1:
The patent changes the chemical transformation pathway from transesterification to hydroprocessing (hydrogenation followed by hydroisomerization), fundamentally altering the reaction parameters and conditions to avoid ester formation and instead produce saturated hydrocarbons with diesel-compatible properties
Solution Approach 2:
The patent converts the harmful oxygen content in vegetable oils (which causes NOx emissions) into a benefit by complete hydrodeoxygenation, transforming the oxygenated triglycerides into pure hydrocarbons that burn cleaner with reduced NOx emissions
2Manufacturing precision
If hydrodeoxygenation is used to remove oxygen from triglycerides, then oxygen is decomposed, but hydrogen consumption increases
Solution Approach 1:
The patent segments the hydroprocessing into two distinct stages: first hydrogenation of unsaturated bonds, then hydroisomerization with controlled hydrodeoxygenation. This segmentation allows optimization of hydrogen consumption at each stage rather than aggressive hydrodeoxygenation from the start
Solution Approach 2:
The patent performs preliminary hydrogenation of unsaturated fatty acids before hydrodeoxygenation, saturating the double bonds first. This preliminary action reduces the complexity of subsequent oxygen removal and minimizes hydrogen consumption during the hydrodeoxygenation step
3Manufacturing precision
If hydrotreatment followed by hydroisomerization is implemented, then cold properties are improved, but intermediate gas-liquid separation is required increasing process complexity
Solution Approach 1:
The patent merges the hydrotreatment and hydroisomerization steps into a single integrated hydroprocessing operation using a bifunctional catalyst that performs both hydrogenation and isomerization simultaneously, eliminating the need for separate intermediate separation units
Solution Approach 2:
The patent employs a universal bifunctional catalyst system (metallic phase on molecular sieve support) that performs multiple functions: hydrogenation of unsaturated bonds, hydroisomerization of linear paraffins, and controlled hydrodeoxygenation, replacing the need for multiple specialized catalysts and process steps
4Device complexity
If sulfur impurities are not eliminated before hydroisomerization, then process simplification is achieved, but catalyst performance deteriorates
Solution Approach 1:
The patent employs a sulfur-tolerant catalyst formulation that can withstand sulfur impurities without deactivation, effectively treating the catalyst as a robust, disposable component that maintains performance despite sulfur exposure, eliminating the need for costly sulfur removal pretreatment
Solution Approach 2:
The patent modifies the catalyst parameters by selecting specific metallic phases (such as nickel or cobalt sulfides) and molecular sieve compositions that are inherently tolerant to sulfur, changing the catalyst's chemical resistance properties to allow direct processing of sulfur-containing feedstocks
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 process achieves high yields of high-quality diesel with low sulfur, nitrogen, and aromatic content, excellent cetane index, and improved cold resistance properties, reducing environmental impact and operational costs.
Implementation Method 1
implementing a zeolitic catalyst with no intermediate gas-liquid separation
Implementation Method 2
The oxygen contained in triglycerides is generally decomposed by hydrodeoxygenation in the presence of hydroprocessing catalyst
Data Source
Figure 1
AI summary
Treating a charge obtained from a renewable source, comprises: (a) hydrotreating the charge in the presence of a fixed bed catalyst comprising hydro-dehydrogenating function and an amorphous support at 200-450[deg] C and at a pressure of 1-10 MPa; (b) separating from the obtained effluent, at least a portion of water and a hydrocarbon base; (c) eliminating nitrogen compounds from the hydrocarbon base; (d) hydroisomerizing the hydrocarbon base in the presence of selective hydroisomerization fixed bed catalyst; and (e) separating from the obtained effluent, hydrogen gas and diesel base. Process of treating a charge obtained from a renewable source, comprises: (a) hydrotreating the charge in the presence of a fixed bed catalyst at a temperature of 200-450[deg] C, at a pressure of 1-10 MPa, and an hourly space velocity of 0.1-10 per hour, and in the presence of a total quantity of hydrogen mixed with the charge at a ratio of hydrogen to charge of 50-1500 Nm 3>of hydrogen/m 3>charge, where the catalyst comprises a hydro-dehydrogenating function and an amorphous support; (b) separating from the effluent obtained from step (a), at least a portion of water and at least one hydrocarbon base; (c) eliminating nitrogen compounds from the hydrocarbon base obtained from step (b); (d) hydroisomerizing of at least a part of the hydrocarbon base obtained from step (c) in the presence of a selective hydroisomerization fixed bed catalyst comprising a hydro-dehydrogenating function and at least one mono-dimensional 10 MR zeolite molecular sieve, where the step (c) is carried out at 150-500[deg] C, at a pressure of 1-10 MPa, at a hourly space velocity of 0.1-10 per hour and in the presence of a total quantity of hydrogen mixed with the charge at a ratio of hydrogen/charge of 70-1000 Nm 3>/m 3>; and (e) separating from the effluent obtained from step (d), the hydrogen gas and at least one diesel base.