Q1: Which of the following gasifiers can be attached to coal based fertiliser plants ?

ANS:B - Kopper-Totzek gasifier.

The Koppers-Totzek gasifier is a type of entrained-flow gasifier used to convert solid carbonaceous materials, such as coal, biomass, or petroleum coke, into synthesis gas (syngas). It operates at high temperatures and pressures and is widely used in industries such as chemicals, refining, and fertilizer production. Here are the key features and principles of the Koppers-Totzek gasifier:

1. Entrained-Flow Design: The Koppers-Totzek gasifier utilizes an entrained-flow design, where the feedstock material is finely ground and suspended in a stream of high-velocity oxidizing gas, typically oxygen or air. This creates a turbulent environment within the gasifier, promoting rapid mixing and efficient conversion of the feedstock into syngas.
2. High Temperatures: The gasification process in the Koppers-Totzek gasifier occurs at high temperatures, typically ranging from 1300°C to 1600°C (2372°F to 2912°F). These high temperatures facilitate the thermal decomposition of the solid carbonaceous material, breaking down complex organic compounds into simpler gases such as hydrogen (H2), carbon monoxide (CO), and methane (CH4).
3. High Pressure: The gasification process in the Koppers-Totzek gasifier often operates at elevated pressures, typically ranging from a few atmospheres to several tens of atmospheres. Operating at high pressure helps increase the efficiency of gasification and allows for the production of syngas with higher energy content and lower impurity levels.
4. Slag Formation: As the solid feedstock material undergoes decomposition in the gasifier, inorganic impurities and ash components are melted and form a molten slag. The slag is removed from the bottom of the gasifier, separating it from the syngas stream and preventing it from contaminating the final product.
5. Versatility: The Koppers-Totzek gasifier is versatile and can process a wide range of solid carbonaceous materials, including coal, biomass, and petroleum coke. This flexibility allows industries to use locally available feedstock materials and adapt to changes in resource availability and market conditions.