A chemical engineer is optimizing a reaction that produces 80 liters of biofuel per batch at 75% efficiency. If the engineer improves the process to 90% efficiency and increases input volume by 20%, how many liters of biofuel are produced per batch now? - Redraw

Understanding the Context

Today, chemical engineers are at the forefront of efforts to scale sustainable fuels efficiently. The original setup produces 80 liters at 75% efficiency—a conversion rate where 75% of input energy becomes usable output. Improving to 90% efficiency means twice as much usable biofuel per reaction cycle. Paired with a 20% increase in input volume, the result is a marked gain in throughput. This shift captures growing interest in energy density and cost-effectiveness, key drivers behind modern biofuel innovation.

What Happens When Efficiency and Input Scale Up?

Let’s break it down:
At 75% efficiency with 80 liters per batch, the usable output is truly 80 liters (since 75% of input becomes useful).
But now, efficiency jumps to 90%, and input rises by 20%. Assuming linear scaling, the usable biofuel increases proportionally.

First, calculate the original input volume:
80 liters = 75% efficiency → Input = 80 ÷ 0.75 = 106.67 liters of raw feed.

Key Insights

A 20% increase in input means new input = 106.67 × 1.20 = 128 liters.

At improved 90% efficiency, usable output = 128 × 0.90 = 115.2 liters.

So, the new biofuel output per batch is approximately 115 liters—a 43.75% improvement from the original batch size.

Common Questions About Optimization

How does efficiency affect actual production?
Efficiency represents the ratio of usable output to total input energy or material. Higher efficiency means less waste and more usable product per cycle.

Final Thoughts

Why not just increase input endlessly?
Process limits—equipment capacity, safety thresholds, and material availability—define practical input bounds. Smart optimization works within these, not beyond.

Is this realistic for real-world refineries?
Yes. Modern chemical plants continuously refine reaction conditions, feedstock quality, and process heat integration to approach theoretical maxima safely and sustainably.

Opportunities and Realistic Expectations

This kind of optimization supports scalable, cost-competitive biofuels—critical for displacing fossil fuels. However, full-scale deployment depends on infrastructure, feedstock supply, and policy incentives. Engineers balance technical limits with economic feasibility, ensuring breakthroughs translate into tangible progress.

Understanding Common Misconceptions

Some may assume a 90% efficiency crystalizes every molecule—implying perfect extraction. In reality, losses due to side reactions, heat dissipation, and equipment inertia remain unavoidable. Optimization maximizes potential, not eliminates all inefficiencies.