HCFC-244bb Feed Purification for Low-Impurity HFO-1234yf
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Solution Overview
Problem
Existing methods for producing 2,3,3-tetrafluoropropene (HFO-1234yf) suffer from impurity formation, particularly 3,3,3-trifluoropropene (HFO-1243zf) and vinyl chloride (1140), which lead to yield loss and reactor coking due to the presence of impurities like 3-chloro-1,1,1-trifluoropropane (HCFC-253fb) and high boilers during dehydrochlorination.
Innovation Solution
A manufacturing process that involves removing impurities such as HCFC-253fb and high boilers from the feed before dehydrochlorination, using azeotropic distillation, scrubbing, and distillation to control the formation of 1243zf and 1140 below predetermined thresholds, thereby improving yield and reactor uptime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dehydrochlorination is performed without removing impurities first, then the process is simpler and faster, but impurity formation increases leading to yield loss and reactor coking
Solution Approach 1:
The patent applies preliminary action by removing impurities (HCFC-253fb and high boilers) from the feed stream before the dehydrochlorination reaction occurs. This is achieved through distillation columns that separate and remove impurities prior to reaction, preventing their conversion into unwanted byproducts during dehydrochlorination, thereby improving yield and reducing reactor coking while maintaining production efficiency
2Reliability
If impurities are removed to less than 200 ppm levels, then yield and reactor uptime improve, but process complexity and cost increase
Solution Approach 1:
The patent applies the extraction principle by specifically removing harmful impurities (HCFC-253fb and high boilers) from the feed stream through distillation columns before dehydrochlorination. This targeted removal of specific impurities to less than 200 ppm levels prevents their conversion into unwanted byproducts, improving reactor uptime and yield while managing process complexity through focused separation rather than comprehensive purification
3Manufacturing precision
If multiple distillation columns are used for impurity removal, then impurity levels decrease, but capital investment and operating costs increase
Solution Approach 1:
The patent applies segmentation by using multiple distillation columns arranged in sequence, where each column targets specific impurity ranges. The first column removes light impurities and the second column removes heavy impurities, achieving comprehensive purification through divided stages. This segmented approach enables effective impurity removal to less than 200 ppm levels while managing capital investment and operating costs through modular, staged separation rather than requiring a single complex system
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 reduced impurity levels, enhancing the yield and efficiency of HFO-1234yf production by minimizing the formation of undesirable byproducts and preventing reactor degradation.
Implementation Method 1
removing the at least one impurity from the feed until the feed contains less than 200 ppm of the at least one impurity
Implementation Method 2
dehydrochlorinating the HCFC-244bb in the feed to form a product stream containing HFO-1234yf
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
The present disclosure provides various manufacturing processes for the production of 2,3,3,3-tetrafluoropropene (HFO-1234yf or 1234yf). Such methods may allow for the improved yields, more economical processes, and waste reduction in the production of 1234yf and subsequent processes.