1. Pre-treatment: hazards and control of feedstock impurities
In the gas treatment process, the impurities contained in the raw gas, such as liquid free water, solid particles, H₂O, acid gas (CO₂, H₂S), etc., not only accelerate the corrosion of the equipment and clogging of the pipeline, but also may affect the stability of the subsequent process and the quality of the product, so it is necessary to strictly control the impurity indicators. Pre-treatment adopts a step-by-step purification strategy, firstly, the use of alcohol and amine method to efficiently remove the acidic gas, and then with the help of molecular sieve adsorption technology, to further remove water, heavy hydrocarbons, mercury and other impurities, in order to lay the foundation for the subsequent treatment.
2. Acid gas removal: multiple technologies and customised solutions
There are many different technologies for acid gas removal, including molecular sieve adsorption method, alcohol-amine method, modified hot potassium method, sulfone-amine method and so on. The selection of solvents and process design for different technologies requires comprehensive consideration of the composition of the raw gas, pressure conditions, product quality standards, and overall costs and operating expenses. With rich experience in the industry, the deacidification plant is customised based on the ethanolamine method to ensure efficient acid gas removal according to the characteristics of the gas components and the working conditions at the site.
3. Dewatering: Efficient solutions to fit the scenario
Natural gas dehydration mainly adopts absorption and adsorption methods. For small-scale projects, the molecular sieve adsorption method has the advantage of efficient dewatering even under low partial pressure of water vapour due to its strong adsorption performance, while further removing residual acid gas. In addition, the device is easy to operate, compact and occupies a small space, which is highly suitable for small-scale projects. It is worth mentioning that the regas of the molecular sieve system comes from the BOG after recovering the cooling capacity of the re-liquefaction unit, so as to achieve the recycling of energy.
4. Removal of trace mercury and aromatic hydrocarbons: a guarantee of precision purification
In order to ensure that the gas quality meets the stringent standards, the purification equipment adopts targeted technology to deal with trace pollutants. Specialised sulphur-impregnated coal-based activated carbon is used to effectively adsorb and remove possible trace amounts of mercury, while special adsorbents are used for in-depth purification of aromatic hydrocarbons. Through these precise treatment measures, trace impurities in the gas are efficiently removed, and the gas purification effect is guaranteed in all aspects.
Frequently Asked Questions (FAQ)
Q1: What are the main hazards of feedstock impurities in gas treatment?
A1: Impurities like liquid free water, solid particles, H₂O, and acid gases (CO₂, H₂S) accelerate equipment corrosion, cause pipeline clogging, and can negatively affect the stability of subsequent processes as well as final product quality.
Q2: How does the pre-treatment purification strategy work?
A2: Pre-treatment uses a step-by-step purification strategy. First, it uses the alcohol and amine method to efficiently remove acid gases. Second, it utilizes molecular sieve adsorption technology to remove water, heavy hydrocarbons, mercury, and other trace impurities.
Q3: Which technologies can be selected for acid gas removal?
A3: The main options include molecular sieve adsorption, alcohol-amine methods, modified hot potassium methods, and sulfone-amine methods. The design choice depends on raw gas composition, pressure, product standards, and cost requirements.
Q4: Why is molecular sieve adsorption ideal for small-scale dehydration?
A4: It provides highly efficient water removal even under low partial pressure of water vapor, removes residual acid gas, requires less space, is easy to operate, and allows energy recycling from BOG.
Q5: How are trace mercury and aromatic hydrocarbons removed from gas?
A5: Trace mercury is removed using specialized sulfur-impregnated coal-based activated carbon, while aromatic hydrocarbons are deeply purified using targeted adsorbents to ensure overall precision purification.
Hongke Qingneng
