This report describes a two-step process that creates 1,550 lb/hr 1,3-butadiene from a feed of effluent steel mill gas. The goal for this plant was 100,000 gallons of 1,3- butadiene per year, but preliminary economic analysis suggested a 20x scale up was necessary for economic viability. The first step of this process uses fermenters inoculated with cl. autoethanogenum to convert carbon monoxide-rich effluent gas to 2,3- butanediol. This intermediate is fed to a thermo-catalytic converter to produce 1,3- butanediene. Ethanol and MEK are both byproducts of this process that were initially isolated and sold for greater profit. In the pages to follow, a detailed design and economic analysis for this process is presented for a plant in China. Process flow sheets, energy and utility requirements, and equipment summaries are provided and analyzed. Process profitability is highly sensitive to the pricing of butadiene and ethanol. It is shown that the plant is likely will be unprofitable at prevailing commodities prices. The investment has an internal rate of return of 0.7%, and net present value of $-74.4MM using a discount rate of 15%. This project has a capital investment of $126.2MM. The return on investment (ROI) is 2.0%, with a payback period of 10.3 years. Alternatives can be explored for different process configurations and varying product goals. A few possibilities are presented within this paper.