High-Pressure Reduction Unit Gas Recycle Pressure Control
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Solution Overview
Problem
Current methods for reducing iron oxide-containing starting materials in high-pressure reduction units suffer from an unfavorable energy balance, leading to inefficiencies and reduced output rates due to energy loss in pressure adjustments and fluctuations in feed gas volumes.
Innovation Solution
A method where a reducing gas is introduced into a high-pressure reduction unit, with top gas recycled and reintroduced as part of the feed gas, and compressed in stages to minimize energy loss, using multiple recycle gas partial streams with varying pressures to optimize energy usage and adapt to operational fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the feed gas is compressed to a minimum pressure level before being introduced into the PSA device for CO2 separation, then the CO2 separation can work effectively, but large amounts of energy are consumed
Solution Approach 1:
The invention performs preliminary compression of the feed gas to a minimum pressure level (e.g., 2 bar) before CO2 separation, but then maintains this pressure throughout the reduction unit operation. This preliminary action ensures PSA effectiveness while avoiding continuous high-energy compression during operation, as the reduction unit itself operates at this pressure level.
Solution Approach 2:
The invention changes the operating pressure parameter of the reduction unit to match the compressed feed gas pressure (2-20 bar). This parameter change allows the system to utilize the compressed gas directly without additional compression steps, converting a high-energy consumption scenario into an efficient operating condition.
2Power
If the reducing gas pressure level is too high for the reduction unit, then the reduction potential is high, but the mechanical energy in the form of pressure energy must be dissipated via valves
Solution Approach 1:
The invention changes the operating pressure parameter of the reduction unit to match the compressed feed gas pressure (2-20 bar). This parameter change allows the system to utilize the compressed gas directly without additional compression steps, converting a high-energy consumption scenario into an efficient operating condition.
Solution Approach 2:
The invention creates equipotential conditions by matching the pressure level of the compressed feed gas with the operating pressure of the reduction unit. This eliminates pressure differentials that would otherwise require energy-dissipating valves, allowing the reducing gas to enter the reduction unit without mechanical energy loss.
3Ease of manufacture
If the feed gas pressure is reduced to a relatively low pressure during cooling and cleaning processes, then the gas can be processed safely, but the pressure energy is withdrawn and the gas is at low pressure for reduction
Solution Approach 1:
The invention performs preliminary compression of the feed gas to a minimum pressure level (e.g., 2 bar) before CO2 separation, but then maintains this pressure throughout the reduction unit operation. This preliminary action ensures PSA effectiveness while avoiding continuous high-energy compression during operation, as the reduction unit itself operates at this pressure level.
4Productivity
If the top gas is drawn off at a lower pressure than the reducing gas supplied, then the reduction process can proceed, but the top gas must be compressed to high pressure for CO2 separation
Solution Approach 1:
The invention changes the operating pressure parameter of the reduction unit to match the compressed feed gas pressure (2-20 bar). This parameter change allows the system to utilize the compressed gas directly without additional compression steps, converting a high-energy consumption scenario into an efficient operating condition.
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 enhances the energy balance, increases output rates, reduces plant component dimensions, and improves responsiveness to operational changes by efficiently managing pressure energy and maintaining a favorable energy balance.
Implementation Method 1
with compression devices arranged in the feed gas line, with the feed gas receiving the recycle gas
Implementation Method 2
This separation is carried out using known devices for separating CO 2 , such as PSA devices (pressure swing adsorption)
Implementation Method 3
feed materials containing iron oxide, such as iron ore, materials containing iron ore, partially reduced materials containing iron oxide, are reduced in a high-pressure reduction unit by introducing a reducing gas into the high-pressure reduction unit
Data Source
AI summary
The method comprises introducing a reducing gas into a high-pressure reducing unit (1), withdrawing the reducing gas as top gas from the high-pressure reducing unit, adding a portion of the top gas to a feed gas as a recycle gas, where the reducing gas is generated by separating carbon dioxide from a gas mixture obtained from the addition of the recycle gas to the feed gas after compression process, and adding the recycle gas to the feed gas or the gas mixture. A direct reduction-export gas line pressure control device (10) is arranged to adjust a pressure of reducing gas and/or top gas. The method comprises introducing a reducing gas into a high-pressure reducing unit (1), withdrawing the reducing gas as top gas from the high-pressure reducing unit, adding a portion of the top gas to a feed gas as a recycle gas, where the reducing gas is generated by separating carbon dioxide from a gas mixture obtained from the addition of the recycle gas to the feed gas after compression process, and adding the recycle gas to the feed gas or the gas mixture. A direct reduction-export gas line pressure control device (10) is arranged to adjust a pressure of the reducing gas and/or a pressure of the top gas. The top gas withdrawn from the reduction unit is purified and/or subjected to a heat exchanger. The feed gas comprises an export gas from a plant for production of iron, a blast furnace gas, a crucible gas, a synthesis gas from a charcoal gasifier, a charcoal gas, and a coke-oven gas. The top gas comprises export gas obtained from a blast furnace or a reduction shaft or an off gas obtained from fluidized bed reduction aggregate for iron production, and has a pressure of 3-7 bars. An independent claim is included for a device for reducing iron-oxide-containing feedstocks.