The origins of coal gasification trace back to the late 18th century, when the need for efficient lighting solutions spurred experimentation with gaseous fuels. The earliest practical application emerged in 1792, when Scottish engineer William Murdoch demonstrated the use of coal gas for lighting by heating coal in an iron retort. This process yielded a flammable gas mixture, later termed "town gas," which consisted primarily of hydrogen, methane, and carbon monoxide. By 1807, the first public street lighting using coal gas was installed in London, marking the beginning of the gasification era.

The 19th century saw rapid advancements in gasification technology as demand for urban lighting grew. Improved retort designs and the development of vertical retorts increased gas yield and efficiency. The introduction of water-gas shift reactions in the mid-1800s further enhanced hydrogen production by reacting steam with carbon monoxide to produce additional hydrogen and carbon dioxide. This period also saw the establishment of centralized gasworks, which distributed town gas through pipelines to homes and businesses.

A major milestone arrived in the early 20th century with the development of the Lurgi process in Germany. Patented in 1927, this method utilized pressurized gasification to improve reaction kinetics and increase hydrogen output. The Lurgi reactor operated at pressures up to 3 MPa and temperatures around 900°C, enabling more efficient conversion of coal into syngas (a mixture of hydrogen and carbon monoxide). This technology became foundational for large-scale coal gasification, particularly in regions with abundant coal reserves.

World War II accelerated interest in coal-derived fuels, including hydrogen for industrial applications. Germany’s Fischer-Tropsch process, which converted syngas into liquid hydrocarbons, relied heavily on coal gasification. Post-war, the focus shifted to optimizing gasification for chemical production and energy. The 1950s and 1960s saw the commercialization of the Koppers-Totzek process, which operated at atmospheric pressure but achieved high temperatures (up to 1600°C) to gasify pulverized coal. This method improved flexibility in feedstock selection and reduced tar formation.

The oil crises of the 1970s renewed interest in coal as a feedstock for hydrogen and synthetic fuels. The U.S. Department of Energy initiated research into advanced gasification technologies, leading to the development of entrained-flow gasifiers. These systems, such as the GE Energy and Shell designs, utilized finely ground coal particles and oxygen at high pressures (2–8 MPa) and temperatures (1300–1600°C) to achieve near-complete carbon conversion. Entrained-flow gasifiers became the dominant technology for modern coal-to-hydrogen projects due to their high efficiency and scalability.

Environmental concerns in the late 20th century drove innovations in gasification cleanup processes. Sulfur and particulate removal technologies, such as acid gas scrubbing and ceramic filters, were integrated into gasification plants to reduce emissions. The introduction of combined cycle systems, where syngas fueled turbines and waste heat generated steam for additional power, improved overall efficiency. By the 1990s, integrated gasification combined cycle (IGCC) plants demonstrated the potential for cleaner coal-based power and hydrogen co-production.

The 21st century has seen further refinements in gasification technology, particularly in carbon capture and storage (CCS). Advanced gasifiers now incorporate pre-combustion carbon capture, where CO2 is separated from syngas before hydrogen combustion. Pilot projects, such as the U.S. FutureGen initiative, tested the feasibility of near-zero-emission hydrogen production from coal. Meanwhile, developments in catalytic gasification and chemical looping have explored alternative pathways to reduce energy penalties associated with traditional methods.

Modern coal gasification for hydrogen production leverages decades of incremental improvements. Current systems achieve thermal efficiencies exceeding 60% and can process a variety of coal grades, including low-rank coals. The syngas produced is purified through pressure swing adsorption or membrane separation to yield high-purity hydrogen (>99.9%). These advancements have positioned coal gasification as a transitional technology in regions where renewable hydrogen production remains limited by infrastructure or resource availability.

Key technological milestones in coal gasification development:

- 1792: William Murdoch demonstrates coal gas lighting.
- 1807: First public gas lighting in London.
- Mid-1800s: Water-gas shift reaction enhances hydrogen yield.
- 1927: Lurgi pressurized gasification process patented.
- 1950s: Koppers-Totzek process commercialized.
- 1970s: Entrained-flow gasifiers developed for high efficiency.
- 1990s: IGCC plants integrate gasification with power generation.
- 2000s: CCS integration reduces carbon emissions.

The evolution of coal gasification reflects a continuous drive to improve efficiency, scalability, and environmental performance. From its humble beginnings as a source of town gas to its current role in hydrogen production, the technology has adapted to meet changing energy demands while laying the groundwork for future innovations in clean energy systems.