Autoclave Feed Preheating Control for Precise Reactor Temperature
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Solution Overview
Problem
Precise temperature control of aqueous slurries in metallurgical processes is challenging, particularly in preheating vessels, leading to suboptimal conditions within autoclaves, necessitating auxiliary heating or cooling to maintain desired process conditions.
Innovation Solution
A method and apparatus that involve preheating a feed material using a first heating medium, sensing the temperature within the reactor vessel, and adjusting the preheating level by bypassing the heating section or supplying additional heating or cooling media to maintain optimal temperature, utilizing a controller to determine the necessary adjustments based on temperature signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If flash steam pressure is controlled by venting in the preheating vessel, then the slurry can be preheated, but precise control of the slurry temperature is difficult to achieve
Solution Approach 1:
The patent implements a feedback control system where the temperature of the slurry is continuously monitored and the flash steam pressure is adjusted based on the temperature measurement to maintain precise control. The system uses the temperature feedback signal to modulate the venting rate or heating rate, ensuring the slurry reaches and maintains the desired temperature setpoint.
Solution Approach 2:
The patent changes the operating parameters of the preheating vessel by adjusting flash steam pressure, heating rate, and slurry flow rate to optimize temperature control. By dynamically modifying these parameters based on process conditions, the system achieves precise temperature control that overcomes the limitations of simple venting-based pressure control.
2Productivity
If the slurry is preheated to a high temperature to maximize leaching efficiency, then the leaching process efficiency improves, but the slurry may become too hot for optimal autoclave operation
Solution Approach 1:
The patent performs preliminary heating of the slurry in a preheating vessel before the autoclave, using flash steam from the autoclave discharge. This preliminary action recovers heat that would otherwise be wasted and pre-heats the slurry to an optimal temperature, improving autoclave efficiency while preventing excessive temperature buildup that would require auxiliary cooling.
Solution Approach 2:
The patent converts the harmful waste heat from autoclave discharge into a beneficial heating resource by using it to preheat the incoming slurry. This heat recovery approach improves overall process efficiency and eliminates the need for auxiliary heating while preventing the slurry from being too cold for optimal autoclave operation.
3Temperature
If auxiliary heating or cooling is provided to maintain desired process conditions in the autoclave, then optimal process conditions are achieved, but energy consumption and system complexity increase
Solution Approach 1:
The patent converts the waste heat from autoclave discharge into a useful heating resource for preheating the incoming slurry. This heat recovery eliminates the need for auxiliary heating in most cases and reduces or eliminates the need for auxiliary cooling by optimizing the preheating temperature, thereby reducing overall energy consumption.
Solution Approach 2:
The patent merges the heating function into the preheating vessel by using flash steam from the autoclave, combining the waste heat recovery and slurry preheating operations into a single integrated system. This eliminates the need for separate auxiliary heating systems and reduces overall system complexity.
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 ensures precise temperature control within the reactor vessel, reducing the need for auxiliary heating or cooling and optimizing process conditions, thereby enhancing efficiency and energy savings.
Implementation Method 1
preheating at least a portion of the feed material with a first heating medium in a heating section of a preheating vessel
Implementation Method 2
sensing the temperature within the reactor vessel
Implementation Method 3
an amount of a second heating medium is supplied to the reactor vessel sufficient to increase the temperature within the reactor vessel
Implementation Method 4
the second heating medium is steam and/or a reagent which reacts exothermically with the minerals or metal-containing compounds of the slurry
Implementation Method 5
an amount of a cooling medium is supplied to the reactor vessel sufficient to decrease the temperature within the reactor vessel
Data Source
AI summary
A method and apparatus for controlling a temperature within a reactor vessel such as an autoclave operating at elevated temperature and pressure. The apparatus includes a preheating vessel for preheating a feed material such as an aqueous slurry. The preheating vessel forms part of a preheating control system providing the primary means of temperature control within the reactor vessel. The apparatus also comprises secondary means for heating and cooling the reactor. Feed material temperature is increased or decreased by the preheating control system, based on the reactor temperature. Where the preheating control system is at or near its capacity for heating or cooling, the secondary heating or cooling means is activated to bring the reactor temperature within an optimum range.