Low-Pressure VGO Hydrotreating with All-Metal Catalysts

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Solution Overview

Problem

Low-pressure diesel hydrodesulfurization (DHDS) units, designed for earlier sulfur specifications, become less relevant with stricter cetane standards, and face challenges in processing vacuum gas oil (VGO) due to capacity limitations in downstream units like fluidized catalytic cracking (FCC) and hydrocracking (HCU) units.

Innovation Solution

Modify existing low-pressure DHDS units to use all-metal hydrotreating catalysts, incorporating metal oxides like cobalt, molybdenum, and tungsten, and introduce a hot separator with a pump-around circuit to process VGO, reducing sulfur and nitrogen contaminants, and further treat VGO with ionic liquids to enhance processing in downstream units.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If low-pressure DHDS units are used for diesel hydrodesulfurization, then sulfur removal is effective, but the units become less relevant for meeting stricter cetane standards and cannot effectively process VGO

Engineering Contradiction:

Improveability to process different feedstocksVSAvoideffectiveness for original design purpose

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The DHDS unit is modified to handle multiple feedstocks including diesel, VGO, and other hydrocarbon streams. The reactor system can process different feeds by changing catalyst beds or operating conditions, making the unit versatile for various hydroprocessing applications while maintaining effective heteroatom removal.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The unit operates at low pressures (35-50 kg/cm2g) with modified catalyst systems to achieve effective processing of VGO and other feeds. By changing operational parameters and catalyst composition rather than increasing pressure, the unit maintains its design advantages while gaining versatility for different feedstocks.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If downstream FCC and HCU units are used for VGO processing, then VGO can be converted, but these units have capacity limitations that restrict additional feed processing

Engineering Contradiction:

Improveprocessing capacityVSAvoidability to accept additional feeds

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The DHDS unit performs preliminary treatment of VGO by removing sulfur and nitrogen contaminants before the feed enters downstream FCC or HCU units. This pre-processing reduces the load on capacity-constrained downstream units, enabling them to handle additional feedstocks without exceeding their processing capacity.

Inventive Principle:

Principle #10Preliminary action

3Ease of operation

If conventional catalysts are used in DHDS units, then the units are simple to operate, but they cannot effectively process VGO or improve cetane index

Engineering Contradiction:

Improveoperational simplicityVSAvoidability to process VGO and meet cetane standards

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

The catalyst system uses composite materials with metal components (Group V, VI, or VIII metals) comprising 40-50 wt.% of the catalyst, including all-metal catalyst formulations. These advanced catalyst compositions enable VGO processing and cetane improvement while the unit maintains relatively simple operation at low pressures.

Inventive Principle:

Principle #40Composite materials

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

Effectively desulfurize and denitrify VGO at low pressures, reducing the load on FCC and HCU units, allowing for easier processing of additional feeds and improving cetane index of diesel streams.

Implementation Method 1

hydrotreating the heated vacuum gas oil stream under hydrotreating conditions and at a pressure within the range of approximately 35-50 kg/cm2g to form a hydrotreated effluent

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 2

the hot separator includes a pump around circuit that removes a pump around liquid stream from an upper portion of the hot separator via a pump around line, and further wherein the pump around liquid stream is cooled to form a cooled stream

Methodology Applied

Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentUS10392569B2Vacuum gas oil hydrotreating methods and units

Publication Date: 2019.08.27 UOP LLC

AI summary

The present invention relates to a hydrotreating process that includes providing a vacuum gas oil stream; heating the vacuum gas oil stream; passing the heated vacuum gas oil stream to a hydrotreating reactor; passing the hydrotreated effluent to a hot separator to form a gas stream and a liquid stream; passing the gas stream to a cold separator to form a heavy liquid stream, a light liquid stream and a vapor stream; and passing the vapor stream to an amine scrubber. Aspects of certain embodiments of the present invention also relate to a hydrotreating process in which the hydrotreating reactor is operated at a pressure within the range of approximately 35-50 kg/cm2g.