World-wide coal reserves can supply the global demand for primary energy for several centuries.
However, low thickness and structural complexity may constrain the economic exploitation of
many coal deposits. Taking into account these circumstances, underground coal gasification
(UCG) can offer an economical and sustainable approach for coal exploitation and subsequent
feedstock generation from the syngas. The UCG process produces a high-calorific synthesis gas
mainly consisting of methane, hydrogen and carbon dioxide, which can be used for electricity
generation or feedstock production at the surface. Considering the latter, the Urea process can be
applied to establish the nitrogen based fertilizer carbamide (CH4N2O). The required feedstock for
carbamide production in the Urea process can be supplied by UCG syngas. The aim of the
present study was the development of an integrated carbon utilisation concept based on the
coupled UCG-Urea process. A significant amount of carbon dioxide from the UCG synthesis gas
is required for carbamide production in the Urea process, while the excessive carbon dioxide can
be re-injected into the cavities resulting in the coal seams and surrounding strata after the
gasification process. Thus, a new approach for utilisation of carbon dioxide resulting from coal
combustion was developed to provide a coupled technology also comprising geological storage
of excessive carbon dioxide. A theoretical feasibility study considering UCG-Urea process
economics and potentials of UCG and carbon dioxide storage in the gasified strata was conducted for a selected study area in northern Bangladesh revealing the high competitiveness of
the combined technology on the international feedstock markets.