Integrated Fischer-Tropsch Hydroprocessing for Lubricating Base Oils
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Solution Overview
Problem
Current processing schemes for Fischer-Tropsch wax and condensate fractions require high capital and operating costs, leading to the conversion of wax into lower-value liquid fuels rather than high-value lubricating base oils, as they fail to optimize synergies between separate processing trains.
Innovation Solution
An integrated process that separately recovers Fischer-Tropsch wax and condensate, then hydroprocesses the wax and hydrotreats the condensate under optimal conditions, followed by dewaxing and hydrofinishing to produce high-quality lubricating base oils and liquid fuels, with a hydrogen-rich gas recycle loop minimizing equipment needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If Fischer-Tropsch wax is processed into lubricating base oils using conventional processing schemes, then high commercial value products are produced, but high capital investment and operating expenses are required
Solution Approach 1:
The patent divides the Fischer-Tropsch synthesis product into separate fractions (wax and condensate) and processes each through dedicated processing trains. The wax fraction is processed through a wax hydroprocessing unit and dewaxing unit, while the condensate fraction is processed through a condensate hydroprocessing unit. This segmentation allows each train to be optimized for its specific feedstock, reducing overall capital investment and operating costs while maintaining high productivity for both lubricating base oils and liquid fuels.
2Ease of manufacture
If Fischer-Tropsch wax is cracked to yield lower molecular weight material for liquid fuels, then processing costs are reduced, but the commercial value of the product decreases
Solution Approach 1:
The patent employs dynamic processing conditions in the wax hydroprocessing unit, where temperature, pressure, and catalyst selection are optimized based on desired product distribution. The unit can operate under conditions that favor either lubricating base oil production (milder conditions) or liquid fuel production (more severe cracking conditions), allowing flexible adaptation to market demands and optimizing both cost and value outcomes.
3Productivity
If separate processing trains are used for Fischer-Tropsch condensate and wax fraction, then optimal processing conditions can be achieved for each, but processing scheme complexity increases
Solution Approach 1:
The patent merges the separate processing trains through a unified hydrogen recycle system. The hydrogen-rich gas from the dewaxing unit is recycled to the wax hydroprocessing unit, and hydrogen-rich gas from the condensate hydroprocessing unit is also recycled to the wax hydroprocessing unit. This integration reduces overall hydrogen consumption and simplifies the processing scheme while maintaining optimal processing conditions for each fraction.
4Device complexity
If hydrogen-rich gas is recycled from hydrofinishing to dewaxing zone, then equipment needs are minimized, but pressure management becomes more challenging
Solution Approach 1:
The patent utilizes parameter changes in the hydrogen recycle system, where hydrogen-rich gas is recycled at different pressures to different processing zones. The hydrogen-rich gas from hydrofinishing is recycled to the dewaxing zone at a pressure at least as high as the dewaxing zone pressure, eliminating the need for additional compression equipment. This pressure management strategy minimizes equipment needs while maintaining efficient operation.
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 reduces capital and operating costs while maximizing the production of high-value lubricating base oils and liquid fuels by optimizing processing conditions in separate but integrated trains, achieving lower pressure dewaxing and higher pressure hydroprocessing and hydrofinishing, thus enhancing overall yield and product quality.
Implementation Method 1
hydroprocessing the Fischer-Tropsch wax in a wax hydroprocessing zone by contacting the Fischer-Tropsch wax with a hydroprocessing catalyst in the presence of hydrogen under hydroprocessing conditions
Implementation Method 2
hydrotreating the Fischer-Tropsch condensate mixture in a condensate hydrotreating zone by contacting the Fischer-Tropsch condensate mixture with a hydrotreating catalyst in the presence of hydrogen under hydrotreating conditions
Implementation Method 3
dewaxing the waxy intermediate from step (b) in a catalytic dewaxing zone by contacting the waxy intermediate with a dewaxing catalyst in the presence hydrogen under dewaxing conditions
Implementation Method 4
hydrofinishing the base oil from step (f) in a hydrofinishing zone by contacting the base oil with a hydrofinishing catalyst in the presence of hydrogen under hydrofinishing conditions
Data Source
AI summary
An integrated process for producing liquid fuel and lubricating base oil from Fischer-Tropsch derived products which comprises (a) recovering separately from a Fischer-Tropsch synthesis reactor a Fischer-Tropsch wax and condensate; (b) hydroprocessing the wax and recovering a waxy intermediate and a hydrogen-rich normally, liquid fraction; (c) mixing the condensate and at least part of the hydrogen-rich normally liquid fraction to form a Fischer-Tropsch condensate mixture; (d) hydrotreating the condensate mixture and recovering a Fischer-Tropsch condensate product; (e) recovering from the condensate product a liquid fuel; (f) separately dewaxing the waxy intermediate and recovering a base oil; (g) hydrofinishing the base oil; (h) recovering from the hydrofinishing zone a stabilized base oil and a hydrogen-rich gas; and (i) recycling the hydrogen-rich gas to the wax hydroprocessing zone wherein the total pressure in the hydrofinishing zone is at least as high as the total pressure in the wax hydroprocessing zone.