Paul T. Barger

The characteristics of SAPO-34 which influence the conversion of methanol to light olefins

The evaluation of small-pore molecular sieves as catalysts for the conversion of methanol to light olefins (MTO) has shown that SAPO-34 exhibits the best performance based on catalyst life, selectivity to C2–C4 olefins, minimum paraffinic and aromatic byproducts and catalyst stability and regenerability. This paper focuses on the catalyst characteristics which have been shown to influence performance, i.e. shape selectivity, acid site strength, acid site density, particle size and Si content. Of the process conditions, the temperature and feed dilution influence performance by affecting the selectivity.

Economic route for natural gas conversion to ethylene and propylene

Publisher Summary The major component of natural gas is methane, which can be converted into methanol. Methanol is an important industrial intermediate in the manufacture of a number of products such as formaldehyde, acetic acid, and methyl tertiary butyl ether (MTBE). Methanol can also be used as a transportation fuel, but its use has been limited because of its other properties, such as its high water solubility and its blending vapor pressure. Natural gas can be converted to olefins with the help of GTO process. The first step in the process is the conversion of natural gas to methanol followed by the UOP/Hydro methanol to olefins (MTO) process using UOPs unique silicoaluminophosphate (SAPO)-34 catalyst. The primary products are ethylene and propylene. The processes most widely used in the conversion of natural gas to methanol include (1) ICI low-pressure methanol process, (2) Lurgi two-step reforming, and (3) Haldor Topsoe two-step reforming process.

16 Converting natural gas to ethylene and propylene using the UOP/HYDRO MTO process

Abstract The development of new ways to convert natural gas, especially methane, to higher valued products is one of the keys to increasing the utilization of this abundant natural resource. The combination of methanol production using state-of-the-art mega methanol technology with the new methanol-to-olefins (MTO) process developed by UOP and Norsk Hydro provides an economically attractive route from natural gas to ethylene and propylene. These light olefins are feedstocks for a wide variety of high-value petrochemicals and polymers. The UOP/HYDRO MTO process utilizes a SAPO-34-containing catalyst, which provides up to 80% yield of ethylene and propylene at near-complete methanol conversion. The process has great flexibility to produce a product with a range of ethylene/propylene ratios, depending on the operating conditions used. A major end use for both ethylene and propylene is the production of polyolefins. Since polymerization catalysts are very sensitive to a wide variety of poisons, trace by-products in the MTO light oflefin effluent have been identified. Conventional treating methods have been shown to be effective for removing these by-products to the specification levels required for olefin polymerization processes. This work has shown that the ethylene and propylene produced by the MTO process is a suitable feedstock for olefin polymerization.