ANS:C - 1000

The optimum size of an ammonia plant is typically in the range of thousands of tons per day. Therefore, the correct option is: 1000 The size of an ammonia plant is typically measured in terms of its daily production capacity, expressed in tons of ammonia produced per day. The optimum size of an ammonia plant is often around 1000 tons/day. Several factors contribute to determining the optimal size of an ammonia plant:

1. Economies of Scale: Larger plants often benefit from economies of scale, which can result in lower production costs per unit of ammonia. By producing ammonia in larger quantities, the plant can spread its fixed costs (such as infrastructure and equipment) over a greater volume of output, reducing the cost per ton of ammonia produced.
2. Market Demand: The size of the plant is influenced by the demand for ammonia in the market it serves. A larger plant may be economically viable if there is sufficient demand for ammonia products, allowing the plant to operate at high capacity and achieve economies of scale.
3. Feedstock Availability: The availability of raw materials, such as natural gas or hydrogen, can also influence the size of the plant. A plant located near abundant and cost-effective sources of feedstock may be able to operate at a larger scale more efficiently.
4. Technology and Efficiency: Advances in technology and process efficiency can allow larger plants to operate more effectively and competitively. Modern ammonia production technologies, such as steam reforming of natural gas, have improved energy efficiency and production rates, enabling larger plants to be economically viable.

Overall, a plant size of around 1000 tons/day is often considered optimal, striking a balance between economies of scale, market demand, feedstock availability, and technological considerations. However, plant sizes can vary depending on specific circumstances and factors unique to each project.