To design a process for the production of urea-based fertilizer, we will follow the steps below:1. Reaction:The production of urea involves the reaction of ammonia NH3 and carbon dioxide CO2 to form ammonium carbamate NH4COONH2 , which then decomposes to urea CO NH2 2 and water H2O . The overall reaction can be represented as:2 NH3 + CO2 CO NH2 2 + H2O2. Optimal Operating Conditions:Temperature: The optimal temperature for the urea synthesis reaction is in the range of 180-190C. Higher temperatures favor the formation of biuret, which is an undesirable byproduct. Lower temperatures result in lower reaction rates and conversion.Pressure: The reaction is carried out at high pressures, typically in the range of 150-200 bar. High pressure is necessary to achieve high conversion and yield of urea.3. Reactor Design Specifications:The most common reactor design for urea production is the Snamprogetti now Saipem Urea Process, which uses a pool condenser and a high-pressure synthesis section.a. High-Pressure Synthesis Section: The reactor is a vertical, cylindrical vessel with a high-pressure synthesis section at the top. Ammonia and carbon dioxide are fed into the reactor, where they react to form ammonium carbamate. The reaction is exothermic, and the heat generated is removed by boiling water in the pool condenser located at the bottom of the reactor.b. Pool Condenser: The pool condenser is a heat exchanger that cools the reaction mixture and condenses the unreacted ammonia and carbon dioxide. The condensed gases are separated from the liquid urea solution and recycled back to the reactor.c. Stripping Section: The urea solution is then sent to a stripping section, where it is heated to remove any remaining ammonia and carbon dioxide. The stripped gases are also recycled back to the reactor.d. Evaporation and Crystallization: The purified urea solution is then concentrated by evaporation and crystallization to produce solid urea granules or prills.4. Environmental Impacts:a. Greenhouse Gas Emissions: The production of ammonia, a key feedstock for urea synthesis, generates significant greenhouse gas emissions, primarily in the form of CO2. Efforts should be made to minimize these emissions through energy-efficient processes and the use of renewable energy sources.b. Water Consumption: The urea production process requires a significant amount of water for cooling and condensation. Water recycling and efficient water management practices should be implemented to minimize water consumption.c. Waste Management: The urea production process generates solid and liquid wastes, including ammonium salts and process residues. Proper waste management practices should be in place to minimize the environmental impact of these wastes.d. Ammonia Emissions: Ammonia emissions can occur during the production, storage, and transportation of urea-based fertilizers. Proper containment and handling procedures should be in place to minimize these emissions.In conclusion, the production of urea-based fertilizer from ammonia and carbon dioxide gas feedstocks can be achieved using a high-pressure synthesis reactor with a pool condenser. Optimal operating conditions include temperatures of 180-190C and pressures of 150-200 bar. Environmental impacts, such as greenhouse gas emissions, water consumption, waste management, and ammonia emissions, should be addressed through efficient process design and proper management practices.