Published December 2018
Ethylene is the lightest olefinic hydrocarbon. It is also the organic hydrocarbon consumed in the greatest quantity worldwide. As a major chemical intermediate, ethylene is further reacted to produce a wide spectrum of products. The largest single use for ethylene is the manufacturing of polyethylene, with the other major uses being the production of ethylene oxide, ethylene dichloride, and ethylbenzene. Ethylene consumption underpins several different value chains (polyethylene, vinyls, and styrenics) and various economic sectors (construction, packaging, appliances, etc.). The demand for ethylene is therefore broadly tied to GDP. The cost-competitiveness of ethylene production is tied to access to cheap sources of feedstock and proximity to fast-growing markets. Ethylene is generated commercially primarily by the pyrolysis (cracking) of paraffinic hydrocarbon feedstocks, including ethane, propane, butane, and the virgin crude oil fractions of naphtha and atmospheric gasoil. With current record low prices for natural gas, there is growing interest in assessing the pathways for producing ethylene starting from natural gas.
In this report, we present a review and technoeconomic analysis of three conceptual processes to produce ethylene via acetylene derived from the natural gas. Acetylene is industrially produced from natural gas by electric arc or partial combustion processes. We integrate these processes with recently developed liquid-phase selective hydrogenation process for hydrogenating acetylene to produce ethylene. One electric arc–based acetylene production process is considered along with two variants of partial combustion processes—one with full recycle of methanated syngas and another with coproduction of methanol. The processing capacity for all three processes is 235 million lbs/yr (~107,000 MT/yr) of ethylene production.
The production economics assessment in this report is based on a US Gulf Coast location. However, an iPEP Navigator module (an excel-based computer costing model developed by IHS Markit) is attached with this report to allow a quick calculation of the process economics for three other major regions also—Germany, Japan, and China. For every process, the module also allows production economics to be reported in English or metric units in each region.
The technological and economic assessment of the processes is PEP’s independent interpretation of the companies’ commercial processes based on information presented in open literature, such as patents or technical articles, and may not reflect in whole or in part the actual plant configuration. We do believe that they are sufficiently representative of the processes and process economics within the range of accuracy necessary for economic evaluations of the conceptual process designs.