Compact Fischer-Tropsch Reactor Pool Boiling Heat Removal
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Solution Overview
Problem
Current compact Fischer-Tropsch reactors face inefficiencies in heat removal and isothermal operation due to inefficient cooling methods, leading to reduced productivity and stability, especially with the use of flow boiling which is less effective than pool boiling, and require complex designs with additional metal and equipment for effective heat transfer.
Innovation Solution
A compact reactor design with roughened reaction channels and a housing structure optimized for pool boiling, combined with in situ activation of a cobalt catalyst using hydrogen at controlled temperatures and pressures, ensuring efficient heat removal and maintaining isothermal conditions through precise control of synthesis gas flow and pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If flow boiling is used for heat removal in the cooling jacket, then the reactor can operate at high productivity rates, but the heat transfer efficiency decreases due to vapor bubbles moving through narrow channels and reducing the heat transfer factor
Solution Approach 1:
The patent changes the operating parameters of the cooling system by switching from flow boiling to pool boiling mode. This parameter change allows vapor bubbles to detach and rise to the top of the cooling jacket rather than being constrained to move through narrow channels, thereby maintaining high heat transfer efficiency while supporting high productivity rates in the Fischer-Tropsch reactor
2Length of moving object
If compact reactor dimensions are used for transportation, then the plant can be deployed to distant fields, but the heat removal efficiency decreases due to reduced cooling surface area
Solution Approach 1:
The patent utilizes phase transition of water from liquid to vapor in pool boiling mode within the cooling jacket. This phase transition absorbs large amounts of heat (latent heat of vaporization), enabling highly efficient heat removal from the compact reactor channels despite the limited cooling surface area, thus maintaining isothermal operation in the small-scale reactor
Solution Approach 2:
The patent segments the cooling function by separating the reaction zones from the cooling zones with distinct channel structures. The cooling jacket is designed with specific geometry that promotes pool boiling throughout the cooling surface, maximizing heat transfer efficiency in the compact reactor design
3Productivity
If the reactor operates at high productivity rates with intensive heat removal, then the isothermal mode is maintained, but additional cooling equipment and complexity are required
Solution Approach 1:
The patent implements self-service cooling where the reactor's own thermal energy drives the pool boiling process in the cooling jacket. The heat generated by the Fischer-Tropsch reaction automatically generates vapor bubbles that enhance heat transfer, eliminating the need for external cooling equipment or complex control systems while maintaining high productivity rates and isothermal 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
The reactor achieves a high output of synthetic hydrocarbons with a productivity of at least 1160 g C5+/kgr/day and CO conversion of 69%, maintaining isothermal operation and increasing catalyst efficiency by utilizing pool boiling for effective heat transfer and optimizing catalyst activation conditions.
Implementation Method 1
the most effective heat removal required for keeping the Fischer-Tropsch synthesis reactor in the isothermal mode can be ensured under conditions of pool boiling of water in the cooling jacket
Implementation Method 2
The outer surface of the wall of the reaction channels with the catalyst has a roughness of 1.6 to 25 μm
Implementation Method 3
A cobalt Fischer-Tropsch catalyst is activated by passing hydrogen through the reaction channels filled with the catalyst with a space velocity of 1000-30000 h−1 at a temperature of 200-280° C. and a pressure of 0.1-3.0 MPa
Implementation Method 4
The Fischer-Tropsch process for the production of synthetic hydrocarbons is conducted in a compact reactor by feeding synthesis gas to the reaction channels filled with the activated cobalt catalyst
Data Source
AI summary
The invention relates to Fischer-Tropsch synthesis in a compact version. A compact reactor comprises a housing, rectangular reaction channels inside the housing, which are filled with a cobalt catalyst, synthesis gas injection nozzles in the number determined by the ratio of the number of channels to the number of synthesis gas injection nozzles, an input and output nozzle for heat transfer medium on which a pressure controller installed, and an assembly for withdrawing synthetic hydrocarbons. The cobalt catalyst is activated by passing hydrogen through it. Synthetic hydrocarbons are produced by passing synthesis gas through the reaction channels filled with the activated cobalt catalyst. The space velocity of synthesis gas is increased every 300-500 h, followed by returning to the initial process conditions. This provides a high-molecular-weight hydrocarbon output per unit mass of the reactor.