Skip to main content
European Commission logo print header

ZEOLITE BASED CATALYSTS FOR THE PRODUCTION OF HIGHER HYDROCARBONS FROM METHANE

Objetivo

THE AIM OF THIS PROJECT IS TO DEVELOP A NEW ACTIVE AND SELECTIVE CATALYST, BASED MAINLY ON ZEOLITE MOLECULAR SIEVES, FOR THE OXIDATIVE COUPLING OF METHANE TO PRODUCE HIGHER HYDROCARBONS.
This project explored the potential of zeolite-based catalysts in the oxidative coupling of methane to higher hydrocarbons. From the results of a first screening with zeolites varying in pore structure, dimensionality of the pore system and composition, it could be concluded that the acidity of the catalyst has to be as low as possible in order to achieve good selectivities for the information of coupling products.

3 catalytic systems weredeveloped with no or considerably reduced acidity, sodium oxide-calcium oxide mixtures supported on aluminium (V) phosphate, zeolites loaded with sodium oxide by treatment with sodium azide and crystalline metal aluminophosphates with manganese or cobalt in lattice positions. A careful optimisation of the composition of these 3 systems and the reaction conditions resulted in very active and selective catalysts with maximum yields for coupling products around 13% and very good time on stream stabilities.

The research project explored in more detail the potential of zeolite based catalysts in the oxidative coupling of methane to higher hydrocarbons. Zeolites possess essentially 3 properties which make them particulary useful as catalysts and catalyst supports: they can be synthesized in a large variety of structures and compositions, as a result of their cation exchange capability, nearly every desired cation can be introduced and immobilized in the zeolite cages and/or pores for tailoring their catalytic properties and, zeolites possess a very high porosity which enables the deposition of active components with high dispersion and hence high surface area in the zeolite pores. Theexperiments were initially planned to be done at both atmospheric pressure and pressures up to 10 MPa. During the investigation, however, it was recognized that elevated pressures strongly favour the noncatalytic homogeneous gas phase reaction of methane and oxygen. Hence, the results are restricted to atmospheric pressure.

Zeolites and zeolite like materials were tested in the oxidative coupling of methane to higher hydrocarbons. From the results of these investigations it follows that the acidity of the catalyst has to be as low as possible in order to achieve good selectives for the formation of coupling products. Starting from this basic conclusion 3 catalytic systems were developed with none or considerably reduced acidity, involving sodium oxide and calcium oxide mixtures supported on alumophosphate zeolites loaded with sodium oxide treatment with sodium azide and crystalline metalalumophosphates with cobalt or manganese in lattice positions. A careful optimization of the composition of these 3 systems resulted in very active and selective catalysts with maximum yields for coupling products around 13% and high time on stream stabilities.
THERE ARE INDICATIONS THAT ZEOLITES CAN CATALYZE THE OXIDATIVE COUPLING OF METHANE TO HIGHER HYDROCARBONS TWO CLOSELY COOPERATING CONTRACTORS - THE UNIVERSITIES OF LEUVEN (L GROUPE) AND OLDENBURG (O GROUP) - ARE INVOLVED IN THE PROJECT AIMED AT DEVELOPING A ZEOLITE-BASED NEW CATALYST. THE PREPARATION OF A NUMBER OF CATALYSTS TO UNDERGO SUBSEQUENT SCREENING WILL BE SHARED BETWEEN THE TWO GROUPS ACCORDING TO THEIR SPECIFIC EXPERIENCE. THE FOLLOWING MATERIALS WILL BE SYNTHESIZED: - ZEOLITES OF DIFFERENT CHEMICAL COMPOSITION (SIO2, AL2O3; AL2O3, P2O5; SIO2, AL2O3, P2O5; TIO2, AL2O3, P2O5), I.E. OF DIFFERENT ACID/BASE PROPERTIES, AND OF DIFFERENT PORE SIZE, SHAPE AND DISTRIBUTION.
SUBSEQUENT MODIFICATIONS OF THESE ZEOLITES BY TECHNIQUES SUCH AS ION EXCHANGE, DEALUMINIZATION, IMPREGNATION OR A COMBINATION THEREOF LEADING TO THE INTRODUCTION OF MO, BI, SB, PB IONS WILL BE CARRIED OUT BY O GROUP. AMOURPHOUS POLYOXIDES VIA PRECIPITATION, CO-PRECIPITATION, ETC.
MIXED AMORPHOUS POLYOXIDES AND ZEOLITES, NEAT OR MIDIFIED AS INDICATED. SCREENING OF THE ABOVE MENTIONED CATALYSTS WILL THEN BE CARRIED OUT AT ATMOSPHERIC PRESSURE (L GROUP) IN A PURPOSE-BUILT, CONTINUOUS-FLOW, FULLY AUTOMATED APPARATUS CONNECTED ON-LINE TO A GAS CHROMATOGRAPH AND PROCESS COMPUTER. METHANE IN EXCESS OF THE OXYGEN AND TEMPERATURES IN THE RANGE 650 TO 850 DEGREES WILL BE USED. ON SELECTED CATALYSTS, HIGH PRESSURE TESTS (UP TO 10 MPA) WILL BE PERFORMED (O GROUP) IN AN ANALOGOUS SYSTEM. THE BEST-PERFORMING CATALYSTS WILL UNDERGO OPTIMIZATION WITH RESPECT BOTH TO THEIR COMPOSITION AND TO REACTION CONDITIONS. A THOROUGH STUDY, WITH LABELLED REACTANTS, WILL FINALLY BE PERFORMED BY L GROUP ON A SELECTIVE CATALYST TO ELUCIDATE THE REACTION MECHANISM. AN EXTENSIVE KINETIC STUDY ON A SELECTED CATALYST WILL BE PERFORMED BY O GROUP IN THE HIGH-PRESSURE REACTOR WITH A VIEW TO MAKING A SELECTION FROM AMONG SEVERAL MATHEMATICAL MODELS. A RELIABLE MODEL TO SERVE AS A BASIS FOR THE PROCESS DESIGN WILL THEN BE MADE AVAILABLE.

Tema(s)

Data not available

Convocatoria de propuestas

Data not available

Régimen de financiación

CSC - Cost-sharing contracts

Coordinador

UNIVERSITY OF OLDENBURG
Aportación de la UE
Sin datos
Dirección
Ammerlaender Heerstrasse 114/118
26129 OLDENBURG
Alemania

Ver en el mapa

Coste total
Sin datos