Daniel Salerno

Techno-Economic Analysis for the Synthesis of Downstream Processes from the Oxidative Coupling of Methane Reaction

Due to the huge methane deposits worldwide and the great need for the chemical process industry to have new alternatives for olefins production, especially ethylene as starting raw material for numerous products, the direct conversion of methane to ethylene has attracted considerable interest. The main reason that motivates the realization of this new approach is to exploit the availability of un-reacted methane, coming from the exit flue gas products of the OCM reactor, and thus, design an alternative process for methanol and formaldehyde production via OCM and the co-generation of electricity that can make the process economically attractive and designed so as to be industrially implemented. The total project investment, based on total equipment cost, as well as variable and fixed operating costs, was developed based on mass and energy balance information taken from Aspen® Process Economic Analyzer simulation results. The feasibility was evaluated in terms of energy savings, CO2- emission reductions and costs, in comparison to the separate production of methanol with conventional technology alone. Before starting the economic study of the OCM process a preliminary analysis of possible plant locations has been developed. Natural gas is a commodity which price varies strongly from one region to another. Moreover, not only the price of raw materials is affected by the location of the plant but also the costs associated with the production, namely: steam, refrigeration, electricity, fuel, wages, etc., affecting strongly the profitability of a petrochemical project. Due to low natural gas prices in Venezuela, which has the highest production potential in South America, and the highest ethylene sales for the European market, this geographical location has been chosen for economic analysis of this project. Kinetic data of the OCM reaction were taken from the experimental fluidized bed reactor values that has been build in our facilities at TU-Berlin, which reflect promising conversion, selectivity and yield values, testing different catalysts developed at the Institute of Chemistry inside the scope of the UNICAT project. This analysis suggests areas for research focus that might improve the profitability of natural gas conversion, and the results have also been used for the design of the pilot plant which is now being operational at our department.

Ethylene Separation by Feed-Splitting from Light Gases

Separation of ethylene from light gas mixture is one of the most energy intensive separations in petrochemical processes, which uses distillation columns up to 100 m tall and containing over 100 trays due the very small differences in the relative volatilities and very large reflux ratios and also due to the need for sub-ambient temperatures. In recognition of these costs, several attempts have been made in the past to develop processes with less energy and equipment costs. In distillation columns with condenser temperatures significantly below room temperature, such as in ethylene separation towers, it is essential to minimize the expensive energy requirements of the refrigeration cycle that produces the tower reflux. In this work, a solution has been found by expanding the gaseous distillate to decrease its temperature. Moreover, additional solutions applied to conventional ethylene fractionation columns have been implemented here in order to study this behavior. In this contribution, an outlet stream of an Oxidative Coupling of Methane (OCM) reactor, which has been previously stripped of its CO2 content, is also introduced in a demethanizer tower to remove almost all of its CH4 content before entering the ethylene fractionating column. Then, it is cooled exchanging its heat with the distillate stream of the ethylene tower, warming the distillate. The main goal is to reduce the condenser heat duty. This objective is achieved reducing a significant amount of heat required by the condenser, maintaining the mandatory product purity. Due to this improvement, it was also possible to reduce the reboiler heat in almost the same percentage amount that is achieved with the condenser. In addition, the reflux of ethylene column decreases. The sensitivity analysis and the corresponding simulations results will be discussed in order to show the efficiency of the presented approach. These results have also been used for the design of the pilot plant which is now being built at our department. The final design for the OCM process will also be presented.

The systematic design of CO2 capture rocesses applied to the oxidative coupling of methane

The Systematic Design of CO2 Capture Rocesses Applied to the Oxidative Coupling of Methane

Modeling, Simulation, and Economic Evaluation of a Hybrid CO2 Capture Process for Oxidative Coupling of Methane

Abstract The Oxidative Coupling of Methane (OCM) is a direct path for the conversion of methane into ethene. Carbon dioxide is generated as an undesired reaction by-product and must be removed in the downstream separation section. This is commonly achieved by amine scrubbing, which is an energy-intensive process. An alternative hybrid process employing gas separation membranes and absorption is investigated in this contribution. Membrane and absorption processes are modeled and simulated. Several flowsheet configurations and gas compositions, reflecting different OCM reactor concepts, are considered. Preliminary economic analysis is carried out to assess the feasibility of applying this process industrially.