Piston Valve Discharge Control for Polymerization Reactors

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Solution Overview

Problem

Current batchwise discharge systems for polymerization reactors are complex, costly, and prone to clogging, leading to fluctuations in polymer bed levels and monomer concentrations, which affect polymer quality and require frequent maintenance, while continuously operated reactors need stable discharge control to maintain production rates.

Innovation Solution

A piston valve with a modulating actuator is used to directly control the discharge rate of polymer particles from the reactor, minimizing the risk of plugging and allowing for precise flow rate adjustment by modulating the piston stroke within the valve, eliminating the need for multiple valves and reducing polymerization in the discharge line.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If batchwise discharge with on/off valves is used, then polymer can be discharged from the reactor, but the system becomes complex and costly with frequent maintenance requirements

Engineering Contradiction:

Improvepolymer discharge capabilityVSAvoiddischarge system complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent combines multiple valve functions into a single continuously operating control valve at the reactor outlet. This single valve integrates the discharge control function that previously required multiple intermittent valves, thereby reducing system complexity while maintaining polymer discharge capability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent implements continuous operation of the discharge valve instead of intermittent on/off cycling. This continuous operation eliminates the need for complex batchwise discharge systems with multiple valves, reducing both device complexity and maintenance requirements while sustaining productive polymer discharge.

Inventive Principle:

Principle #20Continuity of useful action

2Productivity

If batchwise discharge with multiple on/off valves is used, then polymer discharge is achieved, but maintenance costs increase and system reliability decreases

Engineering Contradiction:

Improvepolymer discharge rateVSAvoidsystem reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent merges multiple valve functions into a single continuously operating control valve, eliminating the reliability issues associated with multiple intermittent valves. This single valve system reduces failure points and maintenance requirements while maintaining effective polymer discharge control.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

By implementing continuous valve operation rather than intermittent on/off cycling, the system achieves more reliable polymer discharge control. The continuous operation eliminates the repeated stress cycles and potential clogging issues associated with frequent valve opening and closing, thereby improving overall system reliability.

Inventive Principle:

Principle #20Continuity of useful action

3Productivity

If intermittent valve operation is used, then polymer discharge is achieved, but pressure oscillations occur requiring large downstream volumes

Engineering Contradiction:

Improvepolymer discharge capabilityVSAvoidpressure stability

Core Design Contradiction:

ProductivityVSStress or pressure

Solution Approach 1:

The patent implements continuous operation of the discharge valve to eliminate the pressure oscillations caused by intermittent valve cycling. This continuous control maintains stable pressure conditions at the reactor outlet without requiring large downstream volumes for pressure dampening, while still achieving effective polymer discharge.

Inventive Principle:

Principle #20Continuity of useful action

4Productivity

If batchwise discharge with on/off valves is used, then polymer can be withdrawn, but fluctuations in polymer bed level and monomer concentration affect polymer quality

Engineering Contradiction:

Improvepolymer withdrawal capabilityVSAvoidpolymer bed stability

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The patent implements continuous operation of the discharge valve to maintain stable polymer bed levels and monomer concentrations within the reactor. This continuous control prevents the fluctuations that occur with batchwise discharge, thereby maintaining consistent polymer product quality while enabling effective polymer withdrawal.

Inventive Principle:

Principle #20Continuity of useful action

Data Source

PatentUS7763685B2Method of discharging a polymer from a polymerization reactor

Publication Date: 2010.07.27 BASELL POLIOLEFINE ITALIA SRL

AI summary

A method of discharging polymer from a continuously operated polymerization reactor, wherein at least a monomer is polymerized to form polymer particles, the method comprising adjusting the discharge rate of the polymer particles by means of a piston valve having a piston element connected to an actuator, said actuator being able to modulate the piston stroke inside said piston valve.