PetroChina Hydroformylation Plant, Sichuan Province, China


The Chinese economy is growing by the day; however with the growth in manufacturing comes the problem of the supply of basic raw materials and the chemical industry in China is central to this. China is one of the largest importers of petrochemicals in Asia, sourcing around 60% of its requirements abroad. The Chinese government is anxious to boost the country's ethylene production to over 10 million tons per year by 2010.

The PetroChina Sichuan Petrochemical Co Ltd, or PetroChina for short, is one of the largest petrochemical companies in one of the industrial centres of China, namely Sichuan province. Currently PetroChina is planning the construction of a new petrochemical facility in Chengdu, Sichuan Province, which will be one of the largest in the southwest of the country.

The new plant, which started its front-end engineering and design phase in December 2007, will produce over 800,000t of ethylene per year and will be open by September 2010.

HYDROFORMYLATION PROCESS

A major part of the new plant will be a new hydroformylation plant to produce aldehydes and alcohols. The hydroformylation section of the petrochemical works will use specialist low-pressure (LP) Oxo Selector 10 technology supplied by the Dow Chemical Co and Davy Process Technology Limited, from technology developed by Union Carbide prior to its acquisition by Dow.

The contract for the technology covers the license, process design, procurement of equipment, technical services and proprietary equipment and materials for the process. The new hydroformylation plant will be the largest custom-constructed single-line low-pressure unit in the world.

The plant will be designed to produce 338,000t of n-butyraldehyde and iso-butyraldehyde per year. There will also be two alcohol production units that will produce 81,800t of 2-ethyhexanol per year and 211,900t of n-butanol per year and 30,800t of iso-butanol.

"The plant will be designed to produce 338,000t of n-butyraldehyde and iso-butyraldehyde per year."

TECHNOLOGY

The low-pressure (LP) Oxo Technology supplied by Dow Chemical is a process that makes use of a mixture of propylene and synthesis gas (a mixture of hydrogen and carbon monoxide) to produce n-butyraldehyde and iso-butyraldehyde (feedstocks can be changed if required). These can then be converted by hydrogen reduction into various alcohols such as 2-ethylhexanol and various butanols.

LP Oxo Technology uses NORMAX catalyst (soluble metal catalyst using cobalt, iridium or rhodium in conjunction with triphenylphosphine ligands) in combination with the LP Oxo SELECTOR Technology. The process can be adjusted to change the butyraldehyde isomer selectivity if different products are required.

The technology can also be used with little modification to convert butene to produce 2-propylheptanol, a new alternative plasticiser alcohol. The Oxo process can produce aldehydes in the range from C3 to C15, other valuable products include C12 to C15 alcohols from Fischer-Tropsch olefins (for detergent production).