Use of SCR in a Hydrogen Plant Integrated with a Stationary Gas Turbine - Case Study: The Port Arthur Steam-Methane Reformer

An “across-the-fence” steam-methane reforming (SMR) hydrogen plant integrated with gas-turbine technology was started up within the past three years at the Premcor refinery in Port Arthur, Texas. This plant, owned and operated by Air Products and Chemicals, Inc., is one of only a handful of SMRs containing an integrated gas turbine. The facility design typifies a growing trend among refiners to outsource their utility needs (i.e., hydrogen, steam, power). It is also one of a very few large industrial combustion sources in the U.S. outside California operating with selective catalytic reduction (SCR) for abatement of nitrogen oxides (NOx). This paper presents a case study of the cooperative effort to apply Best Available Control Technology (BACT) to satisfy increasingly stringent environmental controls in this part of Texas, along with confirming test results. The following issues are addressed: (1) The hydrogen from this plant enables Premcor to process sour crudes into a slate of environmentally friendly refined products. (2) Integration results in more efficient energy utilization and reduced NOx and carbon monoxide (CO) emissions, even without post-combustion controls. (3) Stack testing and the continuous emissions monitoring system (CEMS) confirm that the flue gas from the SMR/gas-turbine combination is successfully being treated using SCR, with provision for continued compliance when either unit is out of service. (4) SCR design incorporates experience from previous SMR cases, where chromium-oxide species deposit on the catalyst to cause activity loss, a phenomenon also affecting SCRs in ethylene plants.