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Increasing distillate production
Meeting RVP with Revised Operating Targets
Refinery RVP Reduction
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Increasing distillate production at zero capital cost



Significantly increasing distillate production can at the earliest stages require no more than process tweaks before significant capital revamps are required.

This is the first of two articles which discuss changes to the crude unit to help produce a higher percentage of distillate products from each barrel of crude processed. The discussion begins with a review of operational tweaks and changes that require zero capital investment. A second article for PTQ will discuss additional opportunities that exist for increased distillate yield, considering options that require minimal capital investment as well as major capital projects that can increase distillate yield

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Many plants maximize their profitability by running up to unit limits or bottlenecks. These constraints may affect the unit charge rate, product rate, or product quality. No matter what the bottleneck, there are often minor changes that can alleviate the restrictions.

Incremental debottlenecking can significantly improve an existing facility's capacity and profitability. Debottlenecking issues should be considered during the following stages of a plant's life:

Debottlenecking Design Points

Debottlenecking Operating Opportunities

Debottlenecking Revamps

There are also many debottlenecking options specific to common refinery units.


Debottlenecking can maximize an existing plant's profitability. However, debottlenecking considerations should be taken into account during the design stage of a new facility to allow for future debottlenecking. Also, sometimes a fresh view of an operating facility can lead to debottlenecking ideas. Specific "tricks" should be considered for specific refinery units. All of these debottlenecking factors can help keep your plant one step ahead of the competition.

Please feel free to contact us if you would like more information, or if we can offer assistance in debottlenecking your plant.


Deep Cut Vacuum Tower Incentives for Various Crudes


Deep cut vacuum tower operations can offer significant incentives over existing operations. Defining the exact incentives, capital costs, and payouts requires an engineering study. However, initial project feasibility studies can benefit from simplified analysis. This paper compares deep cut incentives for typical light and heavy crudes, Brent and Arabian Heavy. The resultant yields structures and incentives are compared for the two crudes, and economic calculations presented for various charge rates. Depending on charge rate and degree of improvement, incentives range from 1 to $10 MM/year.

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Meeting RVP - Different Situations, Different Answers

Lower gasoline RVP specifications have created new operating situations for many refiners. Removal of butanes from gasoline blendstocks has become more critical to meet product RVP requirements. Some refiners have made major unit modifications such as adding Alkylation capacity for butane conversion. Others have debottlenecked existing fractionation equipment increasing butane removal. This article presents three RVP reduction case studies ranging from changing unit operating targets, to maintaining existing equipment, to minor equipment debottlenecking.

Revised Operating Targets

Equipment Fouling

Minor Equipment Debottlenecking


All of these case studies had the common element of reducing the amount of butane and hence RVP of the gasoline blending pool. This is a common requirement of today’s refineries. Sometimes the refinery goals can be met by judicious application of the proper stream specifications. Other times, equipment maintenance or new equipment may be required. Operations and engineering review can provide options and solutions when new requirements or operating problems arise. There is no one right answer for all cases.

Please feel free to contact Ascent if we can answer any questions regarding this study or provide any assistance in meeting your RVP problems. 

The material presented in this section on RVP was the basis for the article entitled, "Refiners Match RVP Reduction Measures to Operating Problems" published in the February 3, 1997, issue of the Oil and Gas Journal. 

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Analysis of alky unit DIB exposes design, operating considerations

As refiners strive to increase unit production or accommodate feed composition changes with minimal capital investment, existing equipment design and operations should be evaluated for opportunities to improve efficiency.

In many cases, throughput limitations can be resolved through review and modification of existing equipment design.

A recent examination of an alkylation plant deisobutanizer (DIB) illustrates design and operating considerations that should be addressed when capacity increases and efficiency improvements are desired.

This sulfuric acid alkylation plant had excess feed and reaction zone capacity. The DIB was the limiting factor; specifically, the DIB reboiler duty was at its maximum and the reboiler steam-supply valves were wide open. A new alkylate Rvp specification of 5.0 psia also was constraining operation.

An engineering review suggested minor design modifications and maintenance items which, when implemented, increased alkylate production capacity by more than 25%.


Full Article


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