Securing our Transportation Future by Using Off-peak Wind to Recycle CO2 into Standard Liquid Fuels

摘要

Doty Energy is developing novel processes that will allow the synthesis of fully carbon-neutral ethanol, gasoline, jet fuel, diesel, and plastics from effluent CO2 and wind-hydrogen at prices that should be competitive with fossil-derived products. Converting CO2 into fuels can eliminate the need for CO2 sequestration and reduce global CO2 emissions by 40%. When the input energy is from off-peak wind and reasonable consideration is included for climate benefit, these Wind-Fuels should compete when petroleum is above $45 to $95/bbl, depending mostly on the price of the off-peak wind energy, which has dropped sharply over the past 18 months in many areas. Prior proposals for synthesizing standard liquid fuels from CO2 and water have previously had projected conversion efficiencies of only 25% to 35%. That is, the chemical energy in the liquid fuels produced (gasoline, ethanol, etc.) would be about 30% of the input renewable energy required. The combination of eight major technical advances we have simulated over the past two years should permit this conversion to be done (ultimately) at about 60% efficiency. A technical overview of the WindFuels production system is presented. It is based largely on the commercially proven technologies of wind energy, water electrolysis, and Fischer Tropsch Synthesis (FTS). Wind energy is used to electrolyze water into hydrogen and oxygen. Some of the hydrogen is used in a process, the so-called reverse water gas shift (RWGS) reaction, that reduces CO2 to carbon monoxide (CO) and water. The CO and the balance of the hydrogen are fed into an FT reactor similar to that commonly used to produce fuels and chemicals from coal or natural gas. The improved processes have been simulated in detail, and key experiments will soon be carried out to help optimize process conditions. It is in our nation’s economic and security interests to produce carbon-neutral transportation fuels domestically at the scale of hundreds of billions of gallons while at the same time to dramatically reduce CO2 emissions. A better alternative for current transportation fuels is needed than those that have previously been advocated – biofuels and hydrogen. The U.S. domestic wind resource and the available effluent CO2 are more than sufficient to produce all the liquid fuels we need plus a similar amount for export. Switching 70% of global transportation fuels from petroleum to WindFuels should be possible over the next 40 years.