Diesel Hydrocracking Pressure Optimization
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Solution Overview
Problem
The increasing demand for heavy naphtha, used as a petrochemical feedstock, is not met by domestic production, leading to reliance on imports, and existing diesel hydrocracking processes require high pressures, posing economic constraints.
Innovation Solution
A process that separates a hydrocarbon feed stream into light and heavy diesel streams, allowing them to be hydrocracked at different pressures in separate reactors, with the light diesel stream processed at lower pressures (3450 kPa to 6205 kPa) and the heavy diesel stream at higher pressures (13790 kPa to 17237 kPa), optimizing yield and reducing capital and operating expenditures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If diesel hydrocracking is performed using existing processes, then heavy naphtha can be produced, but high pressure requirements increase capital and operating expenditures
Solution Approach 1:
The diesel feed stream is separated into light diesel and heavy diesel fractions using a distillation column. The light diesel fraction is hydrocracked at lower pressure (500-900 psig) while the heavy diesel fraction is hydrocracked at higher pressure (2000-2500 psig), allowing each fraction to be processed under optimized conditions that reduce overall capital and operating expenditures
Solution Approach 2:
Different pressure conditions are applied to different fractions of the diesel stream based on their specific properties. The light diesel fraction receives lower pressure treatment while the heavy diesel fraction receives higher pressure treatment, matching the local quality requirements of each fraction for optimal heavy naphtha production
2Productivity
If a single hydrocracking reactor is used for the entire diesel stream, then the process is simpler, but pressure optimization for maximum heavy naphtha yield is limited
Solution Approach 1:
The single hydrocracking reactor is divided into two separate reactors, each dedicated to processing a specific diesel fraction at optimized pressure conditions. This segmentation enables maximum heavy naphtha yield from each fraction while maintaining manageable process complexity through clear functional separation
Solution Approach 2:
The pressure parameter is changed and optimized for each reactor based on the specific fraction being processed. The first reactor operates at 500-900 psig for light diesel while the second reactor operates at 2000-2500 psig for heavy diesel, allowing parameter optimization that maximizes heavy naphtha productivity
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 maximizes heavy naphtha production while reducing capital and operating expenses by integrating with existing hydroprocessing complexes and lowering the pressure requirements for hydrocracking, thus enhancing economic viability and production efficiency.
Implementation Method 1
hydrocracked in the presence of a hydrogen stream and a hydrocracking catalyst
Implementation Method 2
providing a hydrocarbon feed stream comprising diesel to a separation column to provide a light diesel stream and a heavy diesel stream
Data Source
AI summary
A process for maximizing production of heavy naphtha from a hydrocarbon stream is disclosed. The process comprises providing a hydrocarbon feed stream comprising diesel to a separation column to provide a light diesel stream and a heavy diesel stream. The heavy diesel stream is hydrocracked in the presence of a hydrogen stream and a first hydrocracking catalyst in a first hydrocracking reactor at a first hydrocracking pressure of 13790 kPa to 17237 kPa to provide a first hydrocracked effluent stream. The light diesel stream is hydrocracked in the presence of a hydrogen stream and a second hydrocracking catalyst in a second hydrocracking reactor at a second hydrocracking pressure of 3450 kPa to 6205 kPa to provide a second hydrocracked effluent stream. At least a portion of the first hydrocracked effluent stream and at least a portion of the second hydrocracked effluent stream are fractioned to produce heavy naphtha.