BHET Solid Composition Pore Volume and Drying
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The drying of bis-(β-hydroxyethyl) terephthalate (BHET) is problematic due to long drying times at low temperatures, which degrades the quality, and high temperatures that cause stickiness and agglomeration, making the process costly and inefficient.
Innovation Solution
A solid composition comprising at least 90.0 wt. % BHET with a pore volume in the range of 0.20 to 1.0 cm3/g is achieved through crystallization, granulation, and fluid bed drying, which enhances purity, reduces stickiness, and improves transportability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If wet BHET is dried under reduced pressure at relatively low temperatures (40-60°C), then energy consumption is reduced, but drying time becomes excessively long and quality is degraded by colouring
Solution Approach 1:
The patent changes the physical state parameter of BHET from solid to liquid by heating to melting point (90-180°C), then performs drying in this liquid state under reduced pressure. This parameter change allows rapid evaporation of water without the time and quality issues of low-temperature solid drying, while avoiding the stickiness and agglomeration problems of high-temperature drying.
Solution Approach 2:
The patent utilizes the phase transition of BHET from solid to liquid state by heating to its melting point. This phase transition enables the drying process to occur in the liquid state where water can be rapidly evaporated under reduced pressure, solving both the time consumption and quality degradation problems of low-temperature drying.
2Loss of time
If wet BHET is dried by heating to relatively high temperatures (60-90°C), then drying time is reduced, but the surfaces become sticky and BHET agglomerates into blocks
Solution Approach 1:
The patent changes the temperature parameter to reach the melting point of BHET (90-180°C), transforming it from solid to liquid state. In this liquid state, the surface stickiness and agglomeration problems are eliminated, allowing rapid and uniform drying without the harmful effects observed in high-temperature solid drying.
Solution Approach 2:
The patent employs phase transition of BHET from solid to liquid by heating to melting point. This phase change fundamentally alters the surface properties, eliminating stickiness and preventing agglomeration during the drying process, while still achieving rapid water removal.
3Loss of time
If wet BHET is melted and evaporated at temperatures of 90-180°C, then drying time is significantly reduced and quality is improved, but production costs increase significantly
Solution Approach 1:
The patent extracts water from BHET by dissolving BHET in a volatile solvent (such as ethyl acetate, dichloromethane, or toluene) and then evaporating the solvent under reduced pressure. This extraction approach removes water efficiently without requiring high-temperature melting, thereby reducing energy consumption and production costs while maintaining short drying time and high quality.
Solution Approach 2:
The patent introduces a volatile solvent as an intermediary medium to facilitate water removal. The solvent dissolves BHET, allows water to be separated and evaporated under mild conditions, and then is easily removed by evaporation. This intermediary approach achieves efficient drying without the high energy costs of direct thermal melting and evaporation.
4Quantity of substance
If crude BHET from depolymerisation is subjected to evaporation or distillation, then water is removed, but condensation reactions occur making it difficult to obtain high-quality BHET
Solution Approach 1:
The patent uses a volatile solvent as an intermediary to dissolve BHET and facilitate water removal under mild conditions. This intermediary approach prevents condensation reactions that occur during direct evaporation or distillation, enabling获得 high-purity BHET while effectively removing water.
Solution Approach 2:
The patent changes the operating parameters by performing drying in the liquid state at moderate temperatures under reduced pressure, rather than through high-temperature evaporation or distillation. This parameter change prevents condensation reactions while achieving effective water removal and high BHET purity.
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 resulting solid BHET composition is of high purity, has a low stickiness, and exhibits improved flowability and dissolution rates, making it suitable for polymerization into polyethylene terephthalate (PET) with reduced processing times and costs.
Implementation Method 1
fluid bed drying of the granulated crystalline material
Implementation Method 2
granulating the crystalline material
Data Source
AI summary
The invention relates to a solid composition comprising at least 90.0 wt. % bis(2-hydroxyethyl) terephthalate (BHET), as based on dry weight and having a pore volume in the range of 0.20 to 1.0 cm3/g. The porosity is above 25% or even above 35%. The solid composition is made by crystallisation, followed by granulation and fluid bed drying.