Natural Gas to Liquid Fuels via VPSA and Partial Oxidation
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Solution Overview
Problem
There is a need for a safe and efficient method to convert natural gas into liquid fuels and chemicals at a relatively small scale, as existing processes are either hazardous or not adaptable for smaller scale operations due to limitations in oxygen production and transportation challenges of natural gas from smaller fields.
Innovation Solution
The process employs Vacuum Pressure Swing Adsorption (VPSA) to produce a high-purity oxygen stream, which is compressed and reacted with natural gas in a partial oxidation reactor to produce synthesis gas, subsequently converted into liquid fuels and chemicals using Fischer-Tropsch synthesis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If steam methane reforming is used to produce synthesis gas, then the process can operate at large scale with established technology, but the process requires large capital investment and is not suitable for small scale operations
Solution Approach 1:
The invention changes the operating parameters by using partial oxidation instead of steam reforming, operating at lower pressures (1-10 atm) and temperatures (800-1200°C) compared to traditional steam methane reforming, enabling small-scale operation with reduced capital investment while maintaining synthesis gas production
Solution Approach 2:
The invention extracts and removes the steam reforming step entirely, replacing it with direct partial oxidation of natural gas using oxygen from air separation, thereby simplifying the process flow and eliminating the need for complex steam generation and catalyst systems required in traditional reforming
2Manufacturing precision
If partial oxidation with pure oxygen is used, then synthesis gas is produced at ideal H2/CO ratio, but the process requires complex oxygen production infrastructure
Solution Approach 1:
The invention uses partial oxidation with controlled oxygen deficiency (sub-stoichiometric oxygen-to-fuel ratio) to produce synthesis gas at the ideal 2:1 H2/CO ratio, avoiding the need for pure oxygen by deliberately operating in a fuel-rich regime where complete combustion does not occur
Solution Approach 2:
The invention introduces an intermediate air separation unit that produces oxygen-enriched air (30-50% O2) rather than requiring pure oxygen, serving as a mediator between atmospheric air and the partial oxidation reactor to achieve the desired H2/CO ratio without complex oxygen production infrastructure
3Adaptability or versatility
If natural gas from small fields is transported to market, then the gas can be utilized, but transportation infrastructure is lacking and costs are high
Solution Approach 1:
The invention converts the harmful or wasted stranded natural gas into beneficial liquid fuels and chemical feedstocks through on-site partial oxidation and Fischer-Tropsch synthesis, transforming an environmental and economic problem into a valuable resource
Solution Approach 2:
The invention introduces liquid hydrocarbon products as an intermediary form that bridges the gap between stranded natural gas and market requirements, enabling easy transportation via existing liquid fuel infrastructure rather than requiring natural gas pipeline development
4Productivity
If oxygen-sorbent material is used to add oxygen to natural gas, then syngas can be produced, but the process is hazardous and the combustible mixture retention time is very short
Solution Approach 1:
The invention performs preliminary oxygen separation from air before mixing with natural gas, allowing controlled introduction of oxygen to the fuel stream and enabling safe preheating and reaction conditions without the hazards of direct oxygen-sorbent contact methods
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 method effectively produces high-purity oxygen for synthesis gas generation, enabling the efficient conversion of natural gas into marketable liquid fuels and chemicals, such as synthetic crude oil, diesel, and other hydrocarbon products, while being safer and more scalable than previous methods.
Implementation Method 1
The present invention is directed to a process for converting natural gas into liquid fuels and/or liquid chemicals. The process uses an adsorption method to separate oxygen from atmospheric air known as Vacuum Pressure Swing Adsorption (VPSA).
Implementation Method 2
The oxygen rich stream of 80% plus, and preferably 90% plus, oxygen then is compressed to a pressure necessary to make synthesis gas for the process, at preferably between 20-40 Bar.
Implementation Method 3
Partial oxidation uses substantially pure oxygen and optionally a small amount of steam to produce synthesis gas by incomplete combustion of light hydrocarbon gases such as natural gas or ethane.
Implementation Method 4
The Fischer-Tropsch ('FT') Synthesis has been used to convert synthesis gas (carbon monoxide and hydrogen) into hydrocarbon products.
Data Source
AI summary
A process to convert light hydrocarbons such as natural gas to a liquid or liquids. Vacuum pressure swing adsorption (VPSA) is used to produce a stream of relatively high purity oxygen. The relatively high purity oxygen is reacted with light hydrocarbons and steam in a partial oxidation reactor in order to produce synthesis gas. The synthesis gas is thereafter converted to a hydrocarbon liquid or liquids via a Fischer Tropsch or related reaction.