Catalyst Solution Heating and Filtration for Spray Drying
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Solution Overview
Problem
Existing methods for producing oxide catalysts containing Mo, V, and Nb compounds face challenges with solution stability and clogging issues during spray-drying, leading to uneven composition and reduced catalytic performance.
Innovation Solution
A method involving a heating unit in the mixed solution tank and filtration unit in the pipe to prevent clogging, ensuring smooth supply of the aqueous mixed solution to the spray dryer, with a catalyst composition represented by the formula MoVaNbbXcTdZeOn, where X, T, and Z represent specific elements, and a, b, c, d, and e are within defined ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an aqueous mixed solution containing Mo, V, and Nb compounds is prepared and stored for spray-drying, then the catalyst can be produced through catalytic oxidation or ammoxidation, but the solution becomes gelatinous and precipitates due to different pH stable ranges of individual metal ions
Solution Approach 1:
A complexing agent (such as citric acid, ethylenediaminetetraacetic acid, or hydroxyethyliminodiacetic acid) is introduced as an intermediary substance to coordinate with metal ions (Mo, V, Nb) and prevent direct precipitation reactions. The complexing agent forms stable soluble complexes with the metal ions, maintaining solution homogeneity and preventing gelatinization during storage and spray-drying processes.
Solution Approach 2:
The pH value of the aqueous mixed solution is controlled and adjusted to a specific range where all metal ions (Mo, V, Nb) remain stable and soluble. By changing the pH parameter to an optimal value, the solution maintains its homogeneity and prevents precipitation, enabling reliable storage and transport before spray-drying.
2Productivity
If the aqueous mixed solution is supplied through pipes to the spray dryer, then continuous production can be achieved, but clogging occurs in the pipes and spray dryer due to gelatinization
Solution Approach 1:
The complexing agent acts as a protective intermediary throughout the entire supply chain from preparation to spray-drying. It prevents gelatinization in pipes and spray dryer nozzles, ensuring continuous flow without clogging and maintaining reliable supply for continuous production operations.
Solution Approach 2:
The complexing agent is added during the initial solution preparation stage, before the solution enters the supply pipes. This preliminary action of forming stable complexes prevents subsequent gelatinization and clogging issues during transport and spray-drying, ensuring continuous operation without interruptions.
3Ease of operation
If the aqueous mixed solution is heated to return to fluidized state after gelling, then the solution can be supplied to spray dryer, but this is difficult to implement in continuous production steps
Solution Approach 1:
Instead of heating after gelatinization occurs, the complexing agent is added preliminarily during solution preparation to prevent gelatinization from occurring in the first place. This preventive approach eliminates the need for subsequent heating operations and maintains continuous production feasibility.
Solution Approach 2:
The potential harm of gelatinization is converted into a benefit by using the complexing agent to control the gelation process. The complexing agent modifies the gelation behavior to produce a stable, pumpable gel structure that maintains fluidity without requiring heating, enabling continuous operation.
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 prevents clogging and ensures stable supply of the catalyst solution, maintaining catalytic performance and enabling continuous spray-drying, resulting in a high-quality oxide catalyst for producing unsaturated acids or nitriles.
Implementation Method 1
a heating unit in the mixed solution tank and filtration unit in the pipe to prevent clogging
Implementation Method 2
filtration unit in the pipe to remove a solid and/or a gelled product
Data Source
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AI summary
An apparatus for producing a catalyst comprising a tank configured to prepare an aqueous mixed solution containing a Mo compound, a V compound and a Nb compound, a dryer configured to spray-dry the aqueous mixed solution, and a pipe for connecting the tank with the dryer so that the aqueous mixed solution can be supplied from the tank to the dryer, wherein a heater configured to heat the aqueous mixed solution is provided in the tank and/or the pipe, and a filter configured to filtrate the aqueous mixed solution is provided in the pipe.