Development of an Integrated Process Plant for the Conversion of Shale Gas to 1,3 Butadiene

1,3 butadiene is an important feedstock in the production of rubbers and plastics, such as styrene butadiene rubber, polybutadiene rubber, and styrene butadiene latex. As the cracker feedstock around the globe is trending towards lighter feedstock from shale gas, the sustained production of 1,3-butadiene in olefin plants, which is traditionally made via naphtha cracking, is facing big challenges. In this research, a novel integrated plant is developed for the production of 1,3 butadiene from shale gas. The manufacturing process consists of the following steps: (1) conversion of shale gas to methanol, (2) conversion of methanol to ethylene and (3) conversion of ethylene to 1,3 butadiene. In the first step, shale gas is used to produce syngas via steam reforming, which is subsequently transformed to methanol. In the second step, methanol is catalytically converted to ethylene via the MTO process. In the third step, ethylene undergoes a dimerization reaction to produce 1,3 butadiene. The conversion of ethylene is significantly impacted by temperature and the 1,3 butadiene mole fraction in the product stream can vary from about 21% to 31% in the temperature range 1273K – 3273K. Currently, each of these steps are conducted in independent process plants and so there are opportunities to utilize process intensification tools in the integrated process plant. The overall plant is simulated in the ASPENPlus environment and the predictive capabilities of this model is tested by comparing the results from experimental data from individual plants. Then, a variety of process conditions are tested at steady state to optimize the production of 1,3 butadiene. Heat-integration tools are utilized for energy-saving and capital cost reduction opportunities. A comparative economic assessment based on existing plant information indicates that the use of process integration techniques has the potential to reduce costs significantly.