UKCCSRC Call 2 Project: Novel Materials and Reforming Processing Route for the Production of Ready-Separated CO2/N2/H2 from Natural Gas Feedstocks

The world's population is predicted to grow from the current 7 billions to a plateau of approximately 9.2 billions to be reached within the next 60 years, representing roughly a 30 % increase in a not so distant future. The need for more energy efficient methods of producing synthetic fertilisers to meet the resulting increases in food demand and in crude (and bio) oils refining operations -on crudes of ever poorer quality- motivates the scientific community to reconsider the limitations of the mature technologies of synthetic fertilisers production and hydro-refining processes (HDS, HDN, HDM, HDO, hydrocracking) which both rely on the supply of hydrogen. Synthetic fertilisers necessitate hydrogen and nitrogen as feedstocks to make ammonia, which represents the building block for other fertilisers such as urea or ammonium nitrate. The current cheapest and most common means of producing hydrogen is natural gas steam reforming. With an abundance of natural gas reserves becoming exploitable worldwide in recent years via the hydraulic fracturing of shale gas, and given the ever more severe regulations on atmospheric pollution caused by flaring of associated gas from refineries and oil extraction operations, the production of hydrogen is very likely to remain dominated in the years to come by the process of steam reforming using natural gas as its feedstock (aka 'steam methane reforming' or 'SMR'). Conventional SMR technology usually features many unit operations (desulphurisation, pre-reforming, primary reforming, furnace, high and low temperature water gas shift (HT-WGS, LT-WGS), and final separation, with as many heat integration steps in between the units in order to reach an energy efficiency of roughly 80%. This efficiency is only attainable thanks to economies of scale, and SMR plants are consequently enormous. To avoid storage and transport costs of H2, the ammonia/ammonium nitrate/urea plants, or refinery operations are usually conducted near the site of SMR, therefore the production of the final products of fertilisers or clean fuels is very centralised, and thus vulnerable, as well as incurring large distribution costs. With sources of natural gas becoming more remote, widely distributed, shorter lived and quickly relocated, the process of converting natural gas to the final products fertiliser/clean fuel should become more mobile, down-scaleable, as fracking gas wells see their production decay with time and move to different sites. This proposal seeks to reduce significantly the energy and materials demand for the conversion of natural gas feedstocks into ready separated streams of the H2, N2 and CO2 products of steam reforming (the building blocks of urea production) by coupling the in-situ high temperature CO2 capture during the reforming reactions on a solid sorbent (a process called 'sorption enhancement') with the process of chemical looping steam reforming. A process is proposed with only two reactors, a reformer and a pressure/temperature swing separator, appropriate for the new, mobile, small scale industrial utilisation of natural gas, through realising the multiple synergies that are unique to the coupled process, and through the avoidance of expensive materials and awkward reformer geometries. Grant number: UKCCSRC-C2-181.

Tags: Carbon capture and storage, NERC_DDC
Organization: British Geological Survey (BGS)