Gas-Solid Separator for Polyolefin Solids Recovery
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Solution Overview
Problem
Current methods for removing gaseous unreacted hydrocarbon monomer and solvent from polyolefin solids in polyolefin production are inefficient, often requiring inert purge gases and additional process steps, leading to loss of valuable materials and increased costs.
Innovation Solution
Increasing the residence time of polyolefin solids and gaseous components within a gas-solid separation vessel to effectively separate gaseous unreacted hydrocarbon monomer and solvent, thereby producing polyolefin solids substantially free of these components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If vaporized liquid medium is removed by exposing polyolefin solids to an inert purge gas, then gaseous unreacted hydrocarbon monomer and solvent can be stripped from the polyolefin solids, but inert gas needs to be removed via another separation step or vented to flare, and valuable hydrocarbon monomer and solvent are lost
Solution Approach 1:
The patent recovers valuable hydrocarbon monomer and solvent by condensing the vapor stream from the gas-solid separator and returning it to the process, rather than discarding it through flare or requiring additional separation steps for inert gas removal
Solution Approach 2:
The patent extracts the vaporized liquid medium removal function from the traditional inert gas stripping process by using a gas-solid separator that allows gaseous components to be removed through settling and separation without requiring inert purge gas
2Loss of substance
If vaporized liquid medium is removed by using a dryer with mechanical conveyance and heat addition, then gaseous unreacted hydrocarbon monomer and solvent can be desorbed from polyolefin solids, but additional operating and capital costs are incurred and process reliability is impacted
Solution Approach 1:
The patent replaces the mechanical dryer system with a gas-solid separator that uses gravitational settling and phase separation, eliminating the need for mechanical conveyance mechanisms and heat addition equipment
Solution Approach 2:
The patent utilizes phase transitions by allowing vaporized liquid medium to condense from gas phase to liquid phase in the gas-solid separator, enabling separation without requiring thermal energy input
3Loss of substance
If residence time of polyolefin solids and gaseous components is increased within a gas-solid separation vessel, then gaseous unreacted hydrocarbon monomer and solvent can be effectively separated from polyolefin solids, but larger vessel volume is required
Solution Approach 1:
The patent enhances separation efficiency by utilizing vertical settling and phase separation dimensions within the gas-solid separator, allowing adequate residence time without requiring excessive horizontal vessel volume
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 avoids the introduction of inert purge gases and minimizes the loss of valuable hydrocarbons, allowing for the recycling of unreacted monomers and solvents, thus enhancing process efficiency and reducing operational costs.
Implementation Method 1
vaporized liquid medium may be absorbed in and/or on the polyolefin solids and/or vaporized liquid medium may be present interstitially amongst the polyolefin solids
Implementation Method 2
the polymerization effluent may be withdrawn from the reactor and the polymer solids may be separated from the liquid medium. Typical polymer recovery and separation systems include subjecting the polymerization effluent to a reduction in pressure so that the liquid medium may vaporize
Data Source
AI summary
Methods for separating gaseous components, such as unreacted hydrocarbon monomer and/or solvent, from polyolefin solids are provided. The methods include flowing a first stream including polyolefin solids and gaseous unreacted hydrocarbon monomer and/or solvent through a portion of a gas-solid separation vessel having a volume sufficient so that polyolefin solids present in the first stream have an increased residence time within the gas-solid separation vessel to separate gaseous unreacted hydrocarbon monomer and/or solvent from the polyolefin solids to produce a second stream including polyolefin solids substantially free of gaseous unreacted hydrocarbon monomer and/or solvent and a third stream including the gaseous unreacted hydrocarbon monomer and/or solvent. Systems for carrying out such methods are also provided.