Catalyst Feed Control During Transition Periods

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

During catalyst transitions in chemical reactors, it is challenging to determine the instantaneous reaction rate in real-time due to changing process variables, leading to potential deviations from desired reaction rates, which can result in off-spec products, reactor fouling, and increased catalyst waste.

Innovation Solution

Implementing a method that uses real-time measured process variables and material balances to calculate the overall instantaneous reaction rate within the reactor, allowing for immediate adjustments to the catalyst feed rate, employing a continuous ideal stirred tank reactor model to determine the fractions of each catalyst and adjust the feed accordingly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If laboratory tests are used to determine reaction rate, then measurement accuracy is improved, but response time deteriorates due to lag time

Engineering Contradiction:

Improvereaction rate determination accuracyVSAvoidresponse time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces manual laboratory testing (mechanical/chemical analysis) with an automated computational system that calculates reaction rates in real-time using measured process variables and pre-stored kinetic data, eliminating the time-consuming laboratory test step while maintaining accuracy

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates a virtual model of the reactor system that replicates actual reaction conditions, allowing reaction rate determination through computational calculation rather than physical laboratory testing, thus providing real-time data without time delay

Inventive Principle:

Principle #26Copying

2Manufacturing precision

If catalyst feed rate is adjusted frequently during transition, then reaction rate control is improved, but system complexity increases

Engineering Contradiction:

Improvereaction rate controlVSAvoidcontrol system complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent implements a closed-loop feedback control system where the calculated reaction rate is continuously compared against target values, and catalyst feed rate adjustments are automatically made based on the deviation, enabling precise control through a systematic approach

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent employs dynamic control strategies that adapt the catalyst feed rate in real-time based on changing reactor conditions during transition, using calculated reaction rates to modulate feed rate dynamically rather than using fixed schedules

Inventive Principle:

Principle #15Dynamics

3Productivity

If real-time reaction rate monitoring is implemented, then productivity is improved through faster transitions, but measurement and calculation complexity increases

Engineering Contradiction:

Improvecatalyst transition speedVSAvoidmonitoring system complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent creates a multi-functional control system that simultaneously performs data acquisition from multiple sensors, real-time calculation of reaction rates using kinetic models, prediction of future rates, and automatic control adjustments, consolidating multiple functions into an integrated system that improves productivity without proportionally increasing complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 enables responsive control of the instantaneous reaction rate, minimizing off-spec products, speeding up catalyst transitions, and reducing waste by maintaining the reaction rate within desired limits during transitions.

Implementation Method 1

determining an overall instantaneous reaction rate based on measured process variables and a material balance

Methodology Applied

Scientific EffectMaterial balance:

Implementation Method 2

Catalysts can be employed to facilitate the formation of products through chemical reactions

Methodology Applied

Scientific EffectCatalysis: Catalysis

Data Source

PatentUS8940239B2Catalyst feed control during catalyst transition periods

Publication Date: 2015.01.27 CHEVRON PHILLIPS CHEMICAL COMPANY LP

AI summary

Techniques are provided for operating a reactor during a catalyst transition period. The instantaneous reaction rate during a catalyst transition period can be determined using real-time measured process variables, and material balance calculations to provide an instantaneous reaction rate in approximately real time. According to certain embodiments, a material balance can be performed on the reactor system using a continuous ideal stirred tank reactor to determine the fractions of each type of catalyst that are present in the reactor, as well as the overall weight percent of catalyst in the reactor. A controller can then calculate the overall instantaneous reaction rate based on the respective catalyst fractions and the overall weight percent of catalyst in the reactor. The catalyst feed rate can then be adjusted based on the determined instantaneous reaction rate to maintain the instantaneous reaction rate within desired limits during a catalyst transition period.