Andrussow Reactor Mixing Element for HCN Yield
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Solution Overview
Problem
Current reactors for producing hydrogen cyanide (HCN) using the Andrussow process face challenges in achieving high yield, long catalyst service life, and low energy requirements for HCN isolation, while maintaining cost-effectiveness.
Innovation Solution
A reactor design featuring a reactor vessel with a mixing element and a gas-permeable intermediate layer between the gas supply area and the catalyst, which enhances gas mixing and flow uniformity, reducing energy consumption and extending catalyst life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional reactor design without mixing element is used, then device complexity is low, but HCN yield and production output are insufficient
Solution Approach 1:
A mixing element is introduced as an intermediary component between the gas supply area and the catalyst. This mixing element consists of a porous support structure with platinum group metal particles deposited on it, serving as both a mixing device and a catalytic support. The mixing element promotes uniform distribution of reactant gases before they reach the catalyst, thereby increasing HCN yield and production output while adding only a single modular component to the reactor system.
2Use of energy by moving object
If conventional reactor design is used, then energy requirements for HCN isolation are high, but HCN concentration in reaction gas is low
Solution Approach 1:
The mixing element changes the flow parameters of the reactant gases by forcing them through a porous structure, creating uniform velocity distribution and enhanced mixing. This parameter change in gas flow leads to more complete and uniform reactions, increasing HCN concentration in the reaction gas from conventional levels to above 90% by volume, thereby reducing energy requirements for subsequent HCN isolation and purification processes.
3Duration of action of stationary object
If conventional reactor design without protective layer is used, then device complexity is low, but catalyst service life is short
Solution Approach 1:
The mixing element provides localized protection to the catalyst by creating a uniform flow distribution that prevents localized overheating and mechanical erosion. The porous structure of the mixing element acts as a flow distributor that ensures even gas distribution across the catalyst surface, preventing hot spots and extending catalyst service life without requiring an additional protective layer between the gas supply and catalyst.
4Stability of the object's composition
If conventional reactor design is used, then gas mixing and flow uniformity are insufficient, but device complexity is low
Solution Approach 1:
The mixing element serves as an intermediary flow distribution device between the gas supply area and the catalyst. Gas enters the mixing element through a distributed pattern of holes in its support structure, forcing the gas to mix and redistribute before exiting uniformly toward the catalyst. This intermediary mixing element creates stable and uniform gas flow composition, ensuring consistent reaction conditions across the entire catalyst surface.
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 reactor design significantly increases HCN yield and production output while reducing energy requirements for HCN isolation and extending catalyst service life, achieving high HCN concentration in the reaction gas.
Implementation Method 1
at least one mixing element and at least one gas-permeable intermediate layer are provided between the gas supply area and the catalyst
Implementation Method 2
at least one gas-permeable intermediate layer are provided between the gas supply area and the catalyst, and the mixing element is arranged between the gas supply area and the gas-permeable intermediate layer
Implementation Method 3
The reactant gas mixture, which generally comprises methane or a methane-containing natural gas stream, ammonia and oxygen, is passed over catalyst networks in a reactor and reacted at temperatures of approximately 1000 °C
Implementation Method 4
CH 4 + NH 3 + 3/2 O 2 → HCN + 3 H 2 O dHr=-473.9 kJ
Implementation Method 5
The reaction gas is quickly cooled to approx. 150 - 200 °C in a waste heat boiler
Implementation Method 6
passes through a washing column in which the unreacted NH 3 is washed out with dilute sulfuric acid
Implementation Method 7
In a subsequent absorption column, HCN is absorbed in cold water
Data Source
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AI summary
The present invention relates to a reactor (1) for preparing hydrogen cyanide by the Andrussow process, comprising a reactor vessel (2), at least one gas inlet (3) which opens into a gas inlet region (4), an outlet for the reaction products (5) and a catalyst (6), wherein at least one mixing element (7) and at least one gas-permeable intermediate layer (8) are provided within the reactor vessel (2) between the gas inlet region (4) and the catalyst (6), said mixing element (7) being arranged between the gas inlet region (4) and the gas-permeable intermediate layer (8). The present invention additionally describes a process for preparing HCN, in which an inventive reactor is used.