Refinery Sludge Thermal Treatment via Plasma Vitrification

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Solution Overview

Problem

Current methods for disposing of refinery sludge, such as dumping, biological treatment, solvent extraction, and thermal treatment systems, face challenges including high costs, long process times, incompatibility with increasing material volumes, and safety issues due to the physico-chemical characteristics of the sludge, which require a more efficient and economical solution.

Innovation Solution

A continuous thermal treatment process comprising four phases: drying, gasification, combustion, and inertization, using a gasification system with incremental oxygen and water vapor injection, and vitrification with plasma torches, which reduces solid volumes by over 80% and produces self-sustaining syngas, eliminating the need for external heating sources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If dumping is used for sludge disposal, then disposal is simple and economical, but it is no longer allowed due to legislation changes and dump saturation

Engineering Contradiction:
Improvedisposal simplicityVSAvoidlegality and capacity availability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the physical-chemical parameters of sludge through thermal treatment (heating to 700-950°C), transforming it from a hazardous waste with high calorific power into an inert solid product with low calorific power, thereby meeting legislative requirements for dump disposal

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces biological treatment mechanisms with thermal treatment mechanisms (combustion and gasification), achieving faster processing times and producing inert products that can be safely disposed of, while also generating energy through syngas production

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Object-affected harmful factors

If biological treatment is used for sludge disposal, then treatment is environmentally friendly, but process times are long (order of days) and plants are complex

Engineering Contradiction:
Improveenvironmental friendlinessVSAvoidprocess time
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The patent replaces biological decomposition mechanisms with thermal combustion and gasification mechanisms, reducing processing time from days to minutes while maintaining environmental benefits through complete oxidation of organic matter and energy recovery

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the treatment temperature parameter from ambient (biological) to high temperature (700-950°C thermal treatment), dramatically accelerating the treatment process and producing inert products faster than biological methods

Inventive Principle:
Principle #35Parameter changes

3Quantity of substance

If solvent extraction is used for oil recovery, then oil can be recovered, but the process is complex and not compatible with increasing material volumes

Engineering Contradiction:
Improveoil recoveryVSAvoidprocess complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent replaces solvent extraction mechanisms with thermal gasification mechanisms, directly converting organic matter to gas and inert residue without requiring complex extraction solvents, thereby simplifying the process and handling larger volumes more efficiently

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts the oil fraction through thermal decomposition and gasification, separating it from the solid residue, and recovers it as syngas which can be used for energy production, achieving both simplification and scalability

Inventive Principle:
Principle #2Taking out (Extraction)

4Productivity

If fixed bed or bubbling ovens are used for thermal treatment, then treatment can be performed, but safety issues arise from dangerous emissions and rheological characteristics of solid product

Engineering Contradiction:
Improvetreatment capabilityVSAvoidsafety from dangerous emissions
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent optimizes temperature parameters (700-950°C for gasification, 850-1200°C for combustion) and residence time parameters to ensure complete oxidation of organic matter, minimizing dangerous emissions while maintaining high productivity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent incorporates feedback mechanisms through syngas recycling to the gasification zone and combustion product recycling to drying and gasification phases, maintaining safe operating conditions and optimizing treatment efficiency continuously

Inventive Principle:
Principle #23Feedback

5Volume of stationary object

If thermal treatment is used for sludge, then volume reduction is achieved, but external heating sources are required

Engineering Contradiction:
Improvesolid volume reductionVSAvoidexternal heating energy
Core Design Contradiction:
Volume of stationary objectVSUse of energy by moving object

Solution Approach 1:

The patent implements self-service heating by recycling syngas produced during gasification to the combustion zone and combustion products to the drying and gasification phases, allowing the system to sustain itself thermally without external heating sources while achieving significant volume reduction

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent establishes continuous recycling of thermal energy through syngas and combustion products throughout the treatment process, ensuring uninterrupted thermal treatment and maximizing volume reduction efficiency without requiring external energy inputs

Inventive Principle:
Principle #20Continuity of useful 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

The process achieves significant volume reduction and produces inert products, with syngas thermally sustaining the volume reduction process, ensuring efficient and economical treatment of refinery sludge without external heating contributions.

Implementation Method 1

gasification of the dried sludge, at a temperature ranging from 750 to 950°C, for a time of 30 to 60 minutes, in the presence of a gas containing oxygen and water vapour, fed with the incremental differentiated modality, with the associated production of synthesis gas (CO + H2)

Methodology Applied
Scientific EffectGasification: Pyrolysis

Implementation Method 2

inertization of the solid residue, at a temperature ranging from 1,300 to 1,500°C, by vitrification with plasma torches

Methodology Applied
Scientific EffectVitrification: Vitrification

Implementation Method 3

inertization of the solid residue, at a temperature ranging from 1,300 to 1,500°C, by vitrification with plasma torches

Methodology Applied
Scientific EffectPlasma heating: Plasma

Implementation Method 4

combustion of the synthesis gas at a temperature ranging from 850 to 1,200 °C and recycling of the combustion products for the drying and gasification phases

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 5

drying of the refinery sludge, possibly mixed with pet-coke (petroleum coke), at a temperature ranging from 110 to 120°C

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP2454349B1Process and apparatus for the thermal treatment of refinery sludge
Publication Date: 2018.09.12 ENI SPA
  • EP2454349B1 patent drawingFigure 1
  • EP2454349B1 patent drawingFigure 2

AI summary

A continuous process for the thermal treatment of a refinery sludge, comprising the following operations: a. drying of the refinery sludge, possibly mixed with pet-coke, at a temperature ranging from 110 to 120°C; b. gasification of the dried sludge, at a temperature ranging from 750 to 950°C, for a time of 30 to 60 minutes, in the presence of a gas containing oxygen and water vapour, with the associated production of synthesis gas (CO + H2) and a solid residue; c. combustion of the synthesis gas at a temperature ranging from 850 to 1,200°C and recycling of the combustion products for the drying and gasification phases; and d. inertization of the solid residue, at a temperature ranging from 1,300 to 1,500°C, by vitrification with plasma torches.