High Nitrogen Renewable Feedstock Deoxygenation
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Solution Overview
Problem
Renewable biological feedstocks high in nitrogen are challenging to process due to competing nitrogen conversion reactions during deoxygenation, making them more expensive and less commercially viable for producing diesel and jet fuel.
Innovation Solution
Increasing the hydrogen recycle gas rate in the deoxygenation zone, typically between 6000 to 9000 SCF/BBL, to effectively convert high nitrogen feedstocks into linear hydrocarbons, with subsequent isomerization to improve cold flow properties of the effluent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional deoxygenation processes are used on high nitrogen feedstocks, then nitrogen conversion to ammonia competes with deoxygenation reaction, but processing cost increases and commercial value decreases
Solution Approach 1:
The patent changes key process parameters including increasing hydrogen partial pressure, optimizing temperature ranges (300-450°C), adjusting space velocity, and modifying catalyst composition (adding nitrogen-tolerant metals like Ru, Rh, or Ir to conventional catalysts). These parameter changes enable effective deoxygenation of high-nitrogen feedstocks without the competing ammonia formation that plagues conventional processes, thereby maintaining processing efficiency while reducing costs by enabling use of cheaper high-nitrogen feedstocks
2Quantity of substance
If high nitrogen feedstocks are processed using conventional methods, then nitrogen conversion competes with deoxygenation, but commercial viability is reduced
Solution Approach 1:
The patent converts the harmful effect of nitrogen (which normally competes with deoxygenation and reduces efficiency) into a manageable parameter by using nitrogen-tolerant catalysts and optimized conditions. This allows the process to effectively handle high-nitrogen feedstocks like packer tallows, transforming what was previously a disadvantage into an opportunity to utilize abundant, cheaper feedstock sources that were previously unusable, thereby improving both feedstock availability and commercial value
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 allows for efficient conversion of high nitrogen feedstocks into hydrocarbons with reduced nitrogen content, improving processing efficiency and reducing costs, while enhancing fuel properties.
Implementation Method 1
deoxygenating a renewable feedstock in the presence of hydrogen in a deoxygenation zone comprising a catalyst
Implementation Method 2
Organic nitrogen conversion to ammonia is a competing reaction to the necessary deoxygenation reaction
Implementation Method 3
isomerizing the deoxygenated effluent in an isomerization zone comprising a catalyst and being operated under conditions to improve at least one cold flow property
Data Source
AI summary
Processes for producing a fuel from a renewable feedstock which may have more than 60 ppm nitrogen. The renewable feedstock is passed to a deoxygenation zone. A hydrogen stream, preferably formed from a recycled gas, is introduced into the deoxygenation zone at a relatively high rate. The hydrogen introduction may be between 3 to 5 times the rate of hydrogen consumption in the deoxygenation zone. The hydrogen introduction may also be between 6000 to 9000 SCF/BBL. A deoxygenated effluent, comprising less than 1 wppm nitrogen, may be isomerized and separated into one or more product hydrocarbon streams such as a diesel fuel or aviation fuel.