Advanced Assignment: From Grams to Tons - Scale-Up and Optimization of an Aspirin Process

You are a process engineer at a chemical company. The R&D department has successfully synthesized high-purity Aspirin (Acetylsalicylic Acid) on a gram scale. The classic synthesis route is:

Salicylic Acid (C₇H₆O₃) + Acetic Anhydride (C₄H₆O₃) → Aspirin (C₉H₈O₄) + Acetic Acid (C₂H₄O₂)

The lab report indicates that under optimal conditions, they used 5.00 grams of Salicylic Acid with an excess of Acetic Anhydride and obtained 5.82 grams of Aspirin product.

The company now plans to build a continuous production plant with an annual capacity of 500 tons of Aspirin. Your task is to complete the "scale-up" from the lab to industrial production and conduct a comprehensive engineering and economic analysis of the process.

Task 1: Lab-Scale Benchmark Analysis

Write and balance the chemical equation for the aspirin synthesis described above.

Based on the lab data (5.00g Salicylic Acid yielding 5.82g Aspirin), calculate the theoretical yield, actual yield, and percentage yield for this experiment.

Identify which reactant was in excess in the lab experiment and explain why it is common practice to use an excess of one reactant in syntheses.

Task 2: Industrial-Scale Material Balance

Assuming the industrial process can achieve the same yield as the lab, calculate the annual requirement (in tons) of Salicylic Acid and Acetic Anhydride for a 500-ton annual production of Aspirin. Assume a 20% excess of Acetic Anhydride.

Besides the main reactants, industrial production must account for solvents, catalysts, etc. Briefly list and estimate (you may assume) the amount of waste water and solvent generated from washing and purification processes.

Task 3: Energy and Economic Integration

This reaction is exothermic. On a gram scale, heat can be easily dissipated. However, on a ton scale, an uncontrolled exotherm can lead to serious accidents. Propose an industrial reactor design strategy to safely remove the heat of reaction.

Perform a simple cost analysis. Look up (or use provided data) the current market prices for Salicylic Acid and Acetic Anhydride. Based on your calculated annual requirement from Task 2, estimate the annual raw material cost. If the yield is increased by 1%, how much cost would be saved per year?

Task 4: Environmental Impact & Green Chemistry

Does the by-product, Acetic Acid, have any value? Propose a strategy for the recovery and utilization of the Acetic Acid produced in the process to increase the process's economic benefit and reduce its environmental burden.

Based on the 12 Principles of Green Chemistry, evaluate the existing process and suggest potential improvements (e.g., atom economy, use of safer solvents, etc.).

 Deliverables:

一份详细的技术报告，包含所有计算过程、分析结果和设计方案。

A detailed technical report, including all calculation procedures, analysis results, and design proposals.

一页纸的执行摘要，向项目经理汇报你的关键发现、主要成本和推荐方案。

A one-page executive summary, presenting your key findings, major costs, and recommendations to a project manager.

(可选）一个简单的工艺流程框图，展示物料流入、反应器、分离单元和产品流出。

(Optional) A simple Process Flow Diagram (PFD) showing material inflows, the reactor, separation units, and product outflow.