Guide · Layer 2

Build Out the Rest of the Process

Written for: seed / Series A scientist-founder

In 2.1 you built the core reaction in cells. The rest of the process is more of the same: walk your Layer-1 process flow diagram box by box and put each one into Excel at the same level of detail — inputs, what the box does to the stream, outputs. A separator splits one feed into two streams; a heat exchanger changes a temperature, not a composition; a pump or compressor moves a stream and draws power. Keep going until every unit in the diagram has its inputs and outputs in the sheet.

Roll up the flows

With every box in the sheet, total the flows up across the whole system — material and energy alike.

• Connect the material streams end to end — wire each box’s output into the next box’s input by cell reference, so the whole flow moves when you change an upstream number and the totals in still equal the totals out
• Turn each box’s parameters into energy duties — heat of reaction, heating and cooling loads, compression power — and roll them up the same way you roll up the material streams
• Express the energy side per unit of product — energy intensity (MWh/t, GJ/t) is the one physical number Layer 3 turns into both an energy cost and a carbon intensity
• A handful of flows dominate — on the material side the main feed and product, on the energy side usually the reaction heat and the biggest compression or separation load. Size those carefully; proxy the rest

🧭 Coach’s Read

Keep unlike energy carriers on separate lines — a MWh of electricity isn’t a GJ of fuel: different price, different carbon. And a duty in MW says nothing about whether the heat is usable — temperature level decides what can drive what. If one big exotherm can obviously raise steam for a heating step, net it off your energy intensity — then stop. Chasing the last few percent of heat integration is a later-stage job.

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Next: 2.3 — Close the balance →