Hydroprocessing Catalyst Preparation pH Control

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Solution Overview

Problem

The rapid acid-catalyzed decomposition of ammonium nitrate during the calcination of hydroprocessing catalysts poses hazards and destroys catalyst extrudates, and existing methods for removing ammonium nitrate are costly and inefficient, particularly when using nitrate-containing compositions for metal deposition.

Innovation Solution

A method involving the use of an impregnation solution with a pH between 1 and 5.5, which includes a metal nitrate and optionally a modifying agent, to inhibit the rapid decomposition of ammonium nitrate, ensuring the catalyst's stability during calcination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If ammonium-containing component is used in metal deposition, then metal deposition is achieved, but ammonium nitrate forms and causes rapid acid-catalyzed decomposition during calcination

Engineering Contradiction:

Improvemetal depositionVSAvoidrapid decomposition

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful rapid decomposition of ammonium nitrate into a beneficial controlled decomposition by adjusting the pH to 1-5.5. The acidic environment suppresses the formation of ammonium nitrate and promotes controlled decomposition, transforming a hazardous process into a safe and effective metal deposition method.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the pH parameter of the deposition solution to between 1 and 5.5. This parameter change fundamentally alters the chemical behavior of ammonium nitrate, preventing rapid acid-catalyzed decomposition while still allowing effective metal deposition onto the catalyst support.

Inventive Principle:

Principle #35Parameter changes

2Object-generated harmful factors

If washing step is used to remove ammonium nitrate, then ammonium nitrate removal is achieved, but additional waste stream is produced and metal loss occurs

Engineering Contradiction:

Improveammonium nitrate removalVSAvoidmetal loss

Core Design Contradiction:

Object-generated harmful factorsVSLoss of substance

Solution Approach 1:

The patent extracts ammonium nitrate through controlled decomposition at adjusted pH without requiring a separate washing step. By controlling the pH to 1-5.5, ammonium nitrate decomposes in a controlled manner, allowing its removal as gases during calcination while retaining the deposited metals on the catalyst.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent integrates the removal of ammonium nitrate into the calcination process itself. The pH adjustment ensures that ammonium nitrate decomposes continuously and controllably during calcination, eliminating the need for separate washing steps and preventing metal loss that would occur during washing.

Inventive Principle:

Principle #20Continuity of useful action

3Reliability

If pH is adjusted to 1-5.5, then rapid decomposition is inhibited, but additional process step is required

Engineering Contradiction:

Improvecalcination safetyVSAvoidprocess steps

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the pH adjustment step with the metal deposition step into a single integrated process. By adjusting the pH of the deposition solution to 1-5.5 before metal deposition, the safety improvement is achieved without adding a separate process step, as the pH adjustment is performed as part of the deposition preparation.

Inventive Principle:

Principle #5Merging (Combining)

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 effectively prevents the rapid decomposition of ammonium nitrate, maintaining catalyst integrity and reducing waste streams, while ensuring the removal of nitric acid without washing, thus enhancing the hydroprocessing catalyst's performance and safety.

Implementation Method 1

ammonium nitrate will undergo an acid catalyzed rapid exothermic decomposition

Methodology Applied

Scientific EffectAcid catalysis:

Implementation Method 2

The impregnation solution contains at least one metal nitrate and has a pH between 1 and 5.5, inclusive (1≦pH≦5.5)

Methodology Applied

Scientific EffectpH control:

Implementation Method 3

metal deposition is achieved by contacting the catalyst support with an impregnation solution. The impregnation solution contains at least one metal nitrate

Methodology Applied

Scientific EffectMetal deposition: Deposition (physical)

Implementation Method 4

drying the impregnated extrudate at a temperature sufficient to remove the impregnation solution solvent

Methodology Applied

Scientific EffectEvaporation: Evaporation

Implementation Method 5

calcining the dried impregnated extrudate to remove the modifying agent and sufficient to convert at least one metal into oxide

Methodology Applied

Scientific EffectThermal decomposition: Decomposition (biological)

Data Source

PatentUS9512372B2Method for making a hydroprocessing catalyst

Publication Date: 2016.12.06 CHEVRON USA INC

AI summary

The present invention is directed to a method for making a catalyst for hydroprocessing a carbonaceous feedstock under hydroprocessing conditions, and the use of that catalyst. More particularly, the present invention is directed to methods for inhibiting rapid decomposition of ammonium nitrate during calcination of the catalyst following metal impregnation, wherein ammonium nitrate is formed when a nitrate-containing composition and an ammonium-containing component is used in the deposition of metal onto the catalyst.