How To Use Natural Gas In Petrochemical Plant.
Natural gas is an important source of energy in our world. Natural gas is a colorless and odorless gas. Natural gas is one of the most important sources of energy for the development of human civilization. Natural gas is essentially a fossil fuel. We get it from the depths of the soil or the empty cells inside the earth’s surface or mixed with various elements.
Natural Gas is the essential raw materials for Petrochemical Plant, Ammonia Plant, Power Plant, etc. If Natural Gas supplied by a Gas Distribution Company, they are responsible for supply the required quantity with desired pressure at the battery limit. Supply of Feed Stock must be ensured before the initial start-up of all Petrochemical Plant.
Such as an ammonia plant, Feed Stock is Natural Gas.
The component of the natural gas are as follows as:
– CH4 = 97.2 Volume Of Percentage,
– C2H6 = 1.8 Volume Of Percentage,
– C3H8 = 0.5 Volume Of Percentage,
– C4H10 = 0.2 Volume Of Percentage, and
– Sulfur = 5 PPM ( Parts Per Million).
Natural gas extracted from mines is a mixture of different substances. It cannot be used directly. In that case, natural gas has to be made usable. Let’s take a look at what substances are mixed in natural gas.
Impurities are as follows:
Solid Particles, Liquid Droplets, Heavy Hydrocarbon, Sulfur Compounds, CO2, etc.
So natural gas should be treated first to remove those impurities before it is reformed.
The function of Filter and Knock Out drum in battery limit.
At first knock-out, the drum catches the liquid droplets and after the filter separates, the solid particles from the gas before the gas is feed into the Desulfurization Gas Reactor.
If the gas does not treat the solid particles and liquid droplets might plug the pores of the catalysts, in the desulfurization gas reactor.
This unit contains replaceable filters and wire mesh mist extractors.
Gas Hydrate formations in pipelines:
Gas Hydrate formation in Pipelines is the most dangerous thing to interrupt or decrease production efficiency in the process plants. Removing gas hydrate from the pipeline is an expensive process. Therefore, it is very important to prevent gas hydrate formation. In that case, of course, by removing the aqueous material and impurities present in the gas from the battery limit, future unwanted production can be prevented from being disrupted.
Let us now see, what happens to the effect on the catalyst, if the sulfur compound is not removed from the process gas.
=> The sulfur compounds especially H2S and RSH (Mercaptans) have the capacity to reduce the inhibitor present in the Banfield System or CO2 Removal Unit. Besides that, they might be absorbed, by The CO2 Removal Unit or Banfield System. So that the CO2 gas liberated in the Desorber might contain them.
Since the Co2 gas is sent to and used in the Ammonia Plant or Urea Plant. There the corrosion might occur in the Co2 Compressor and Urea Reactor if Co2 contains such Sulfur Compounds.
=> Another important point is that, if sulfur cannot be removed from the feed gas or process gas by the desulfurization vessel, then a layer of sulfur in the catalysts in the subsequent catalyst reactors, reduces or decreases the activity of the catalyst.
Now we see what are the effect of Heavy Hydrocarbon present in Natural Gas or Process Gas.
Heavy Hydrocarbon might be cracked in The Primary Reformer producing carbon deposits. Which would coat the surface of the catalyst, so that the catalyst becomes inactive.
Besides that Heavy Hydrocarbon might cause foaming in absorber and desorber, on The CO2 Removal Unit or Banfield Solution System. So that flooding and carry over might occur in Absorber and Desorber, on The CO2 Removal Unit or Banfield Solution System.
So, to prevent CO2 slip from The Absorber, Heavy Hydrocarbon should be removed from the feed gas prior to entering The CO2 Removable Unit or Banfield Solution System.