Multi-Stage Alkylating Process for Alkyl Benzenes

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Solution Overview

Problem

Existing alkylating processes for alkyl benzenes, such as those using methanol, face inefficiencies due to the decomposition of the alkylating agent, leading to suboptimal utilization and increased energy consumption.

Innovation Solution

A multi-stage alkylating process involving specific reaction zones with varying temperatures and catalysts, including alkali metal ion-exchanged molecular sieves, to inhibit decomposition and enhance the utilization efficiency of alkylating agents like methanol.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If methanol is used as alkylating agent in the presence of alkaline catalyst, then alkyl benzenes can be produced, but methanol decomposes into CO and H2 leading to low utilization efficiency

Engineering Contradiction:

Improveutilization efficiency of alkylating agentVSAvoiddecomposition of methanol

Core Design Contradiction:

ProductivityVSLoss of substance

Solution Approach 1:

The reaction process is divided into multiple reaction zones with different catalysts arranged in sequence. The first zone uses a catalyst with weak alkalinity to minimize methanol decomposition, while subsequent zones use catalysts with progressively stronger alkalinity to enhance alkylating activity. This segmentation allows the system to balance between preventing decomposition and achieving high conversion efficiency.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the key parameter of catalyst alkalinity across different reaction zones. By arranging catalysts with increasing alkalinity (from weak to strong) in sequential zones, the system optimizes the balance between suppressing methanol decomposition in early stages and promoting alkylating reactions in later stages, thereby improving overall utilization efficiency.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If conventional single-stage alkylating process is used, then process is simple, but alkylating agent decomposition occurs reducing efficiency

Engineering Contradiction:

Improveutilization efficiency of alkylating agentVSAvoidnumber of reaction zones

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The reaction system is segmented into multiple zones, each containing catalysts with different alkalinity characteristics. This segmentation enables precise control over the reaction environment in each zone, allowing suppression of decomposition in early zones while maximizing alkylating efficiency in later zones, thereby resolving the contradiction between efficiency improvement and system complexity.

Inventive Principle:

Principle #1Segmentation

3Productivity

If strong alkaline catalyst is used to enhance alkylating activity, then reaction efficiency improves, but alkylating agent decomposition increases

Engineering Contradiction:

Improvealkylating reaction efficiencyVSAvoiddecomposition of alkylating agent

Core Design Contradiction:

ProductivityVSLoss of substance

Solution Approach 1:

The invention segments the catalytic function across multiple zones with progressively stronger alkalinity. This allows the system to use mild catalyst conditions initially to protect against decomposition, then gradually introduce stronger catalytic activity in subsequent zones to enhance reaction efficiency, thereby decoupling the trade-off between activity and decomposition.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The weak alkaline catalyst in the first reaction zone performs a preliminary function of suppressing methanol decomposition before the substrate enters zones with stronger catalysts. This preliminary protective action prevents excessive decomposition that would otherwise occur if strong catalysts were used from the beginning, allowing subsequent zones to operate at high efficiency.

Inventive Principle:

Principle #10Preliminary action

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

Significantly improves the utilization efficiency of alkylating agents by minimizing decomposition, resulting in higher yields of desired products like ethyl benzene and styrene while reducing energy consumption.

Implementation Method 1

an alkyl benzene and a first stream of alkylating agent being fed into a first reaction zone, contacting with a catalyst A, to produce a process stream I

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 2

including alkali metal ion-exchanged molecular sieves

Methodology Applied

Scientific EffectIon Exchange: Ion Exchange

Implementation Method 3

contacting with a catalyst A, to produce a process stream I

Methodology Applied

Scientific EffectCatalysis: Catalysis

Data Source

PatentUS9802876B2Alkylating process for alkyl benzenes

Publication Date: 2017.10.31 CHINA PETROLEUM & CHEMICAL CORP

AI summary

This invention relates to an alkylating process for alkyl benzenes, including the steps of: a) an alkyl benzene and a first stream of alkylating agent being fed into a first reaction zone, contacting with a catalyst A, to produce a process stream I; b) the process stream I and a second stream of alkylating agent being fed into at least one second reaction zone, contacting with a catalyst B, to produce a process stream II; and c) the process stream II being fed into at least one third reaction zone, contacting with a catalyst C, to produce a process stream III containing an alkylate. The present alkylating process can improve the utilization efficiency of the alkylating agent.