Volume 25: Accelerated Energy Innovations and Emerging Technologies

Application of Pnictogen Oxides in Methane Gas Hydrate Formation: Experimental and Modelling Approach Bhavikkumar Mahant, Omkar Singh Kushwaha, Rajnish Kumar

Abstract

The world is shifting towards cleaner energy resources from the high emission energy resources. Natural gas was proved to be one of the better fuels in overall comparison to conventional fuels with higher energy efficiency and lower emission. Natural gas has many challenges in order to store and transport it on a large and small scale. Liquefied natural gas (LNG) is an appropriate option available for large scale transportation of natural gas, while compressed natural gas (CNG) is used for small scale transportation. However, CNG has some disadvantages over the other available alternative way to store natural gas. Past research shows that CNG is not much economical for medium scale transportation. CNG also has inherent safety concerns due to transporting the highly pressurized gas on board. Natural gas hydrate (NGH) can be an optimistic source to store and transport natural gas.
Major studies available in the present world included the use of chemical additives to enhance gas hydrate growth. The chemical additives are divided into two groups: kinetic hydrate promotors (KHPs) and thermodynamic hydrate promotors (THPs). KHPs are chemical additives that can reduce the interface mass transfer limitation by their inherent properties for reducing surface tension using micellization or other physical properties. While THPs are the chemical additives that can shift the phase equilibria requirement of gas hydrate formation by taking part in the process. This study represents alternate chemical additives that can work better than conventional surfactant-based KHPs. Sodium dodecyl sulfate (SDS) is a well-known KHP that has been used to study gas hydrate formation. SDS and other surfactants have the inherent disadvantage of very high foam generation, which can create trouble in the scale-up of the methane gas hydrate technology. Therefore, the need for an hour is to find an inexpensive, biodegradable, efficient, and reliable chemical additive with the added advantage of no foam generation.
The current study demonstrates the use of sodium salts of pnictogen oxides (SPO) to explore methane gas hydrate formation. The performance of the SPO is up to the mark of SDS in order to enhance the gas hydrate formation. There was no foam generation while using the SPO in pure water, and due to their inorganic nature, they can easily dissolve in pure water. The current research shows the result of using 0.01 mole % SPO to form methane gas hydrate, which can open the opportunity for the scale-up by lower utilization of the additives. The morphology of gas hydrate can also be understood with the help of photos taken at a fixed, consecutive interval of time. Artificial intelligence based deep learning approach was utilized to validate the experimental results obtained from this research. An artificial neural network (ANN) was used to develop the model in Matlab R21. The model predicted results were perfectly aligned with the experimental results, which shows the application of this model in future chemical additive selection. The linear regression of the experimental and model predicted results have an R2 value of greater than 0.9, which can explain the reliability of the model. Overall, SPO was proved to be a better alternative to conventional KHPs by using experimental and modeling study.

Keywords Gas hydrate, kinetic hydrate promotors, Artificial intelligence, Artificial Neural Network (ANN)