CO2 Recovery via SURE Process for Sour Gas
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Solution Overview
Problem
Current methods for processing sour gas containing hydrogen sulfide and carbon dioxide are inefficient and costly, particularly when dealing with low-strength acid gas or gases containing contaminants like BTX, leading to operational issues and high capital costs due to the need for large plants and significant fuel loss.
Innovation Solution
A method involving the oxidation of sour gas using high purity oxygen to produce a high concentration carbon dioxide stream, which is then compressed and injected into an oil well for enhanced oil recovery, while optimizing the conversion of hydrogen sulfide to elementary sulfur using a Claus process with SURE Double Combustion for high-strength acid gases and a single reaction furnace for lower strength gases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high purity oxygen is used for oxidation of sour gas, then combustion temperature becomes too high causing safety issues and equipment damage, but using air or oxygen-enriched air reduces oxidation efficiency and increases nitrogen content in the process
Solution Approach 1:
The oxidation process is divided into two separate stages: first, partial oxidation of hydrogen sulfide to sulfur dioxide in a reaction furnace at controlled temperature; second, reaction of sulfur dioxide with residual hydrogen sulfide in a catalytic converter at lower temperature. This segmentation allows efficient oxidation without excessive combustion temperature.
Solution Approach 2:
Sulfur dioxide acts as an intermediary substance. Instead of directly oxidizing all hydrogen sulfide to elemental sulfur at high temperature, the process first converts hydrogen sulfide to sulfur dioxide, which then reacts with remaining hydrogen sulfide to form elemental sulfur. This intermediary step enables controlled reaction at lower temperatures.
2Reliability
If high temperatures are used in the reaction furnace to ensure complete destruction of contaminants like BTX, then fuel consumption increases significantly and plant size must be larger, but lower temperatures result in insufficient destruction and operational issues with solid build-up
Solution Approach 1:
The process separates contaminant destruction from the main oxidation reaction. The reaction furnace operates at moderate temperatures for controlled oxidation, while a dedicated hydrogenation reactor at higher temperatures handles complete destruction of contaminants like BTX, converting them to CO2 and H2O without excessive fuel consumption.
Solution Approach 2:
The process changes temperature parameters at different stages: moderate temperature (800-1200°C) in the reaction furnace for controlled oxidation, then higher temperature in the hydrogenation reactor for complete contaminant destruction. This parameter optimization reduces fuel consumption while ensuring reliable contaminant destruction.
3Productivity
If acid gas enrichment is performed to achieve minimum 40% vol H2S concentration for sulphur recovery unit operation, then additional processing equipment and capital investment are required, but without enrichment the sulphur recovery unit cannot operate efficiently
Solution Approach 1:
The process changes the operational parameter range by successfully operating with acid gas concentrations as low as 20-30% vol H2S, eliminating the need for enrichment to 40% vol. The optimized reaction conditions and catalytic converter design enable efficient sulfur recovery at lower H2S concentrations.
Solution Approach 2:
The process extracts and removes nitrogen from the oxidation air, using high-purity oxygen or oxygen-enriched air instead. This extraction of the inert nitrogen component allows the system to operate efficiently at lower H2S concentrations without requiring additional enrichment equipment.
4Object-affected harmful factors
If carbon dioxide is vented to atmosphere after sulphur recovery, then environmental impact increases, but capturing and compressing CO2 requires additional equipment and operational complexity
Solution Approach 1:
The process converts the harmful CO2 emission into a beneficial product for enhanced oil recovery. The CO2 captured from the sulphur recovery process is compressed and injected into oil reservoirs, where it serves as a solvent to extract additional oil, thereby converting an environmental hazard into an economic and environmental benefit.
Solution Approach 2:
The CO2 handling system serves multiple functions: it captures CO2 from the sulphur recovery process to prevent atmospheric emission, compresses the CO2 for transport, and injects it into oil reservoirs for enhanced oil recovery. This multi-functionality justifies the additional equipment investment.
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 reduces operational costs, minimizes nitrogen in the process, allows for smaller plant designs, and effectively recovers sulfur and carbon dioxide, enhancing oil recovery by utilizing the carbon dioxide in a supercritical state for deeper reservoirs, thus increasing oil output and reducing environmental impact.
Implementation Method 1
oxidation of the sour gas, wherein a part of the hydrogen sulphide is oxidized to sulphur dioxide and water
Implementation Method 2
a catalytic converter connected to the furnace for formation of elementary sulphur from sulphur dioxide and hydrogen sulphide
Implementation Method 3
carbon dioxide and/or carbon dioxide generated by the oxidation of the sour gas is compressed
Implementation Method 4
a hydrogenation reactor connected to the catalytic converter for hydrogenation of the sour gas
Data Source
AI summary
The invention relates to a method for recovering sulphur from a sour gas containing hydrogen sulphide and carbon dioxide, comprising: oxidation of the sour gas, wherein a part of the hydrogen sulphide is oxidized to sulphur dioxide and water, reaction of the resulting sulphur dioxide with the residual hydrogen sulphide to elementary sulphur, and removal of elementary sulphur. According to the invention carbon dioxide and/or carbon dioxide generated by oxidation of the sour gas is compressed, and at least a part of the carbon dioxide is injected into an oil well. Furthermore, the invention relates to a plant suitable for performing the above method.