Published December 2010
Lummus/CB&I has demonstrated, at the continuous semi-commercial plant scale (2 kty with Tianjin Petrochemical Company of China), an integrated process for producing hexene-1 from refinery and chemical plant by-product mixed C4 feedstocks. An intermediate product in the process is commercial grade butene-1, which is the predominant comonomer for producing LLDPE. The Lummus technology uses metathesis chemistry to produce a mixture of 1 mol each of ethylene and hexene-3 from 2 mols of butene-1, separates the intermediate products, then isomerizes the hexene-3 to hexene-1 product. Hexene-1 is used primarily as comonomer for producing LLDPE using low temperature, low pressure technology such as the Unipol® process.
Using a combination of Lummus-provided technical information, plus patent literature, SRIC has developed Class-3 process information, and the corresponding capital and manufacturing costs for a fully continuous, grassroots plant to produce 100 kty of hexene-1. We then used this information to prepare factored estimates for a plant with 50 kty hexene-1 capacity and 200 kty hexene-1 capacity. The hexene-1 capital and manufacturing cost estimates are provided below.
50 kty | 100 kty | 200 kty | |
Total Fixed Capital Cost (US$-MM) | 99.2 | 151.7 | 233.0 |
Total Manufacturing Cost (US$/mt) | 1,003.2 | 908.5 | 843.9 |
Cash Manufacturing Cost (US$/mt) | 804.9 | 756.7 | 727.4 |
Based upon these results, we believe that the Lummus process is commercially viable for a customer that has access to C4 feedstocks priced at naphtha parity, and wishes to produce a combination of hexene-1 (price = US$1,475/mt) and/or butene-1 as LLDPE comonomer without being burdened by the responsibility for managing a wider business selling the other carbon number linear alpha-olefin (LAO) cuts produced by a conventional wide range LAO process. The one caveat for this conclusion is that the customer has access to a steam cracker for purifying and disposing of the other process by-products at reasonable prices.
