The oxidative coupling of methane has been the target of intense scientific and commercial interest for more than thirty years due to the tremendous potential of the technology to reduce costs, energy, and environmental emissions in the production of ethylene. In OCM, methane (CH4) and oxygen (O2) react over a catalyst exothermically to form ethylene (C2H4), water (H2O) and heat, according to the following reaction:
2 CH4 + O2 → C2H4 + 2 H2O + Heat
While the benefits of OCM have been known since the early 1980s, past efforts did not result in a viable catalyst with performance needed for commercialization. These catalysts, while at times achieving promising yield and selectivity, were hampered by very high operating temperatures, low activities, and short lifetimes on the order of hours to days.
Recognizing this, Siluria applied a combination of new innovations in catalyst development, a thorough definition and understanding of the problem, and a highly motivated, creative research and engineering team to develop a unique catalyst to enable OCM to be commercialized.
Siluria’s OCM Catalyst
Siluria combines several highly innovative technologies to create our growing family of commercially viable OCM catalysts. These technologies include: (1) the synthesis of nanowire catalysts allowing us to create vast numbers of unique, novel inorganic nanowire structures; (2) unique templating technologies; and (3) high throughput screening tools to rapidly evaluate hundreds of catalysts, unlike traditional methods that evaluate one catalyst at a time.
Siluria focused on all key process variables such as temperature, pressure, activity, and catalyst stability and lifetime, not solely conversion and selectivity. The result has been the development of OCM catalysts that operate at significantly lower temperature (several hundreds of degrees lower), practical operating pressures (5-10 atmospheres), high activities, and having standard lifetimes of years under said conditions.
Siluria's reaction process is flexible to the source of oxygen and methane feedstocks. For example, the oxygen source can be pure oxygen from a pipeline or an air separation unit (ASU), enriched air from a vapor pressure adsorption (VPSA) unit, or compressed air from a compressor. The catalyst is not impacted by the source of oxygen, although the specific downstream purification and separation processes vary depending upon the oxygen source.
Similarly, Siluria’s OCM catalyst can handle a wide variety of compositional inputs on the methane feedstock in addition to being co-fed ethane for conversion into ethylene. The OCM catalyst can readily accommodate components such as propane, nitrogen, CO2, and water content up to certain limits. This inherent flexibility allows for the use of methane sources ranging from pipeline natural gas, wellhead natural gas, landfill gas and bio-gas, as long as the majority component is methane.