At the 2023 4C Health, Safety & Environmental Conference, Emerson’s Lara Rabbath presented Decarbonization with Steam Methane Reforming for Blue Hydrogen Production. Here is her presentation abstract:
The primary method for blue hydrogen production is mainly from natural gas (methane), using steam methane reforming (SMR) and carbon capture for decarbonization. The hydrogen recovered from the SMR process is commonly used as a feedstock for oil refining, fertilizer, or chemical production. Learn more about the challenges and offered solutions associated with SMR.
Lara opened by sharing how Emerson has technologies & solutions across the hydrogen value chain from production through distribution and dispensing. These technologies and solutions help support the need for expanded production and lower-cost distribution.
She noted that global hydrogen demand is expected to reach almost $12 trillion by 2050. This demand will create opportunities for countries with large natural gas reserves to export clean hydrogen. Feedstock such as natural gas has been widely explored to produce grey hydrogen (hydrogen produced without capturing and sequestering the CO2 emitted during operation).
Natural gas has a high percentage volume of methane, which is a reliable source of hydrogen. Its availability poses little or no challenges to hydrogen production in jurisdictions around the world where it is abundant, including the USA and Canada. The production of natural gas in these countries significantly impacts global use.
Refineries consume most of the hydrogen supply of all industrial sectors, at 57%. Of this percentage, 65% of hydrogen demand in refining is met by hydrogen supplied as a byproduct of the heavy naphtha reforming process. The balance of hydrogen required for hydrotreating, hydrocracking, and isomerization comes from the steam methane reforming (SMR) process. Outside of refining, hydrogen is consumed in processes to produce ammonia, methanol, and direct-reduced iron in the steel industry.
Given that the SMR process and other hydrogen production processes, such as autothermal reforming (ATR) and partial oxidation (POX), produce CO2 as a byproduct, coupling it with carbon capture utilization and storage (CCUS) improves the decarbonization profile. SMR and ATR differ in how heat activates the endothermic steam reforming reaction. In SMR, the catalyst is contained in tubes heated by an external burner. In ATR, a portion of the natural gas is burned to raise the temperature of the process gas before it contacts the catalyst.
From an energy use standpoint, the switch from fossil fuels to hydrogen creates many challenges, such as metal embrittlement from hydrogen, combustion invisibility, and increased NOx emissions. Some ways to address these challenges include increased sensors, flame detectors, and instrumentation. For example, gold-coated diaphragms in pressure measurement devices can avoid hydrogen diffusion into the diaphragm affecting the accuracy and stability of the measurement.
Technologies such as the Rosemount 975HR hydrogen flame detector detect hydrocarbon and hydrogen flames at long distances with high immunity levels to avoid false alarms.
Lara described the instrumentation requirements and best practices for SMR and CCUS. I’ll cover CCUS in a follow-up post.
Some threats to optimum SMR process production include temperature variability, improper steam-to-carbon ratio, flame instability, high tube wall temperature, high excess air in the flue gas, and deficient combustion air. These measurements are essential for optimal production:
Regarding the carbon-to-steam ratio, it’s important to note that natural gas is composed of methane and may include ethane, butane, and propane. A Micro Motion Coriolis mass flow meter can more closely track the molar ratio of the natural gas compared with a volumetric flow meter.
Continuous gas analysis using a Rosemount 700XA gas chromatograph helps monitor the feed gas, intermediate streams, and final product, identify process inefficiencies, and enable further process optimization. It performs highly accurate continuous gas composition analysis that allows monitoring of the reforming and shift converter efficiency.
Different flow measurement technologies are used to measure hydrogen flow across the supply chain. Vortex meters are commonly used since they have fewer leak points than other technologies. Coriolis and Ultrasonic flow measurements are often used for custody transfer between parties. Understanding the process conditions they will operate will determine the best-fit technology.
For water flow measurements, the Rosemount 8800 MultiVariable vortex flow meter is a reliable measurement solution that provides accurate flow rate information to help efficiently produce steam.
Airflow is often difficult to accurately and reliably measure for the reforming furnace due to large line sizes, duct geometry and internals, limited straight runs, and variable flow profiles. The Rosemount Annubar Flow Meter with 485/585 averaging pitot tube and pitot traverse provides accurate (1–2%) airflow measurement. This accuracy supports improved airflow control that optimizes the air-to-fuel ratio, increasing energy efficiency and reducing NOx emissions.
Download the Advanced Measurement Solutions Enhance Blue Hydrogen Production eBook for more on ways to optimize hydrogen production from steam methane reforming processes.
