Ethyl benzene plant with transalkylation catalyst

Ethyl benzene plant with high activity trans alkylation catalyst
Modern commercial ethylbenzene (EB) plants use liquid phase alkylation processes with zeolite catalysts to achieve high crop yields.

The initial reaction is the alkylation of benzene with ethylene.

However, sequential adverse reactions also occur in the alkylator, producing polyalkyl compounds such as diethylbenzene (DEB) and triethylbenzene (TEB).

To maximize EB performance, these polyethylene benzenes (PEBs) are separated in the fractionation section and

A transkylation reactor is recycled in which ethyl groups are transferred to the benzene ring to produce excess ethyl benzene.

Trans-alkylation reactors are designed in a specific EB alkylation process to match the performance of the alkylation reactor.

Due to the high selectivity of the alkylation catalyst, the amount of PEB production in the alkylator is low.

Therefore, the size of a transformer in the EB alkylation process is small.

At a constant EB production rate, the amount of transalkylation catalyst activity required to maximize PEB conversion

, While minimizing heavy-duty residuals, is produced by the amount of PEB and determined in the alkylator.

Increasing the production rate of EB directly leads to the production of high PEB, which increases the hourly space velocity (WHSV) of the transformer.

The reactor temperature must be increased to maintain a constant conversion to reduce PEB recovery. However,

Other stages of reduction include increasing the B / E ratio in the alkylator performance.

Overview of the performance and limitations of EB alkylation of Tianjin Dago Shimi Co.

Tianjin Dagu Chemical Company has EB alkylated (TDCC) unit for the first time in January 2010 with production volume

500,000 tons per year of styrene monomer metric was launched.

This unit was originally used for the use of a dedicated catalyst b in the reactor substrate (RGB) and a six-board alkylator.

It is designed in conjunction with a special c-traction catalyst in trans alloyatar.

During the styrene boom, the TDCC’s main goal was to increase plant capacity.

TDCC and co-authors’ technical teams spend months evaluating specific EB alkylation performance and bottleneck identification

In the field of trans allation, they cooperated by increasing their capacity.

It was found that when a higher PEB is made in the alkylator, the unit is not able to change the converted PEB at the design temperature and WHSV.

Therefore, the operation required to increase the reactor temperature, which inevitably led to heavy production and aging of the catalyst.

Finally, there were two options left:

1. Invest in a new larger reactor to load more catalyst.
2. Use a higher activity transalkylation catalyst.

Option 1was not in terms of capital and economic program.

To support the TDCC’s goal of increasing EB production, and the possibility of increasing plant capacity and relieving the transclusion bottleneck,

Technical teams began an accelerated catalyst development program to identify transcation catalysts with higher activity for potential deployment in the TDCC.

Development of high activity transclusion catalysts:

Experimental plant experience
With an extensive catalog of active ingredients, the technical teams quickly identified 10 catalysts with different types of zeolites, compounds, and treatments to overcome TDCC limitations.

These materials are displayed in a laboratory-scale batch reactor with commercial feed specifications and specifications.

The normalized catalyst activity graphs from this experiment show that six of the 10 catalysts tested showed twice the activity against specific c-specific transcalution catalysts.

In addition to being twice as active as the specific transalkylation catalyst, it was selected for further testing and qualification because it had the shortest production time for commercial production, allowing for faster deployment in the TDCC.

Establishment of high activity trans alylation catalyst: Business experience

Impact of drops in, next-generation catalyst upgrades on proprietary EB alkylation process unit performance evaluation and related hazards. Based on laboratory and experimental laboratory information, risk matrices and mitigation steps were created.

The new catalyst was fully compatible with existing EB alkylation facilities.

No problems were identified due to performance limitations or feed specifications. Finally, it was obtained as the first acceptor of high activity transalkylation catalyst.

Carry

The rapid deployment of next-generation, high-performance catalystshas provided a convenient solution for the purpose of technology for its plant.

The site was able to reach 109% of its design capacity to provide a market value of $ 5.5 million per year.

The new transalkylation catalyst offers higher activity than its predecessor.

With the same load size, higher single-pass PEB conversion was obtained at lower reactor temperatures. The next-generation transalkylation catalyst has been operating in the facility since May 2017 – with slight aging.

In general, high-performance transalkylation catalysts provide operational flexibility to achieve the following benefits:

1. Debottleneck a PE / PEB loop to achieve the highest total unit capacity.
2. Recycle low PEB to save energy on PEB loop.
3. Low start-up temperatures reduce the aging speed of the catalyst, create a larger operating temperature window, and increase the cycle time.
4. Low temperature operation reduces heavy production to minimize fuel depletion.
5. Low initial catalyst filling cost, with reduced load size for fixed unit capacity.