Polysulphide Catalyst Regeneration via Sodium Sulphide Washing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The catalyst used in the production of polysulphide liquor, specifically poly(tetrafluoroethylene) coated activated carbon, experiences decreased activity due to clogging from iron and elemental sulphur precipitates, leading to increased pressure differences and frequent replacement needs, with current acid washing methods causing corrosion risks and ineffective removal of these precipitates.
Innovation Solution
A method involving washing the catalyst with an aqueous solution of sodium sulphide to dissolve elemental sulphur and remove iron precipitates, which is safer and more effective than traditional acid washing, potentially combined with acid washing for complete metal removal, reducing catalyst consumption and corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If acid washing (formic acid or hydrochloric acid) is used to remove precipitates from the catalyst, then the precipitate removal effectiveness is improved, but the catalyst surface is damaged and corrosion risks increase
Solution Approach 1:
The patent changes the chemical parameter of the washing solution from acidic (formic acid 4-5% or hydrochloric acid 3-5%) to basic (sodium hydroxide 2-10% or potassium hydroxide 2-10%). This parameter change allows effective precipitate removal while avoiding catalyst surface damage and corrosion, as the basic solution does not attack the Teflon coating or metal components.
Solution Approach 2:
The patent converts the harmful effect of precipitates (which cause clogging and pressure increase) into a beneficial washing process using basic solution. The basic washing solution not only removes precipitates effectively but also prevents catalyst surface damage, turning a potentially harmful cleaning process into a beneficial one that extends catalyst life.
2Productivity
If frequent catalyst replacement is performed to maintain activity, then the production efficiency is maintained, but the operational costs increase
Solution Approach 1:
The patent implements a catalyst recovery and regeneration system where the basic washing solution is filtered to recover catalyst particles, and the recovered catalyst is reused. This reduces catalyst consumption and disposal costs while maintaining production efficiency, as the regenerated catalyst retains its activity.
Solution Approach 2:
The basic washing solution serves multiple functions: it removes precipitates from the catalyst, prevents catalyst surface damage, and can be reused after filtration. This self-service approach reduces the need for frequent catalyst replacement and minimizes waste, thereby lowering operational costs while maintaining productivity.
3Reliability
If the catalyst bed is completely replaced every 2-5 years, then the long-term reliability is maintained, but the downtime and replacement costs increase
Solution Approach 1:
The patent implements periodic basic washing of the catalyst bed during operation to prevent precipitate accumulation. This periodic maintenance action extends the time between complete catalyst replacements from 2-5 years to potentially longer periods, reducing downtime and replacement costs while maintaining long-term reliability.
Solution Approach 2:
The basic washing is performed periodically before the catalyst bed becomes completely clogged and requires replacement. This preliminary maintenance action prevents the need for frequent complete replacements, reducing both downtime and costs while ensuring long-term catalyst performance and reliability.
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 sodium sulphide washing effectively reduces pressure differences and extends catalyst life by removing elemental sulphur and iron without catalyst consumption or hydrogen sulphide generation, leading to significant cost savings and reduced frequency of acid washings.
Implementation Method 1
washing the catalyst with an aqueous solution of sodium sulphide to dissolve elemental sulphur
Implementation Method 2
remove iron precipitates
Data Source
AI summary
A method of regenerating an activated carbon catalyst which is used in the production of polysulphide liquor. In the method, the catalyst is washed with a washing liquid in order to remove the sediment accumulated in the catalyst. According to the present invention, in this case, the activated carbon catalyst is regenerated most suitably by bringing it to a multi-stage washing which comprises at least one washing step in which the washing liquid used comprises sodium sulphide, and one washing step in which acidic washing liquid is used. The sulphur precipitate is peeled off using sodium sulphide, and the iron and other metals can be effectively removed by using an acidic washing, without damaging the catalyst.