Petroleum Boiler: Flaking Boiler vs Normal Boiler

[Zarquan]

TLDR: With my identical exchangers, a flaking boiler uses 12.3% less heat energy than a standard boiler.

As far as I know, most people who build petroleum boilers achieve the actual conversion of crude oil in to petroleum by heating the crude oil to 403 C. However, there is a better way!

As anyone who has dug too close to the magma biome in an oil biome knows, when you have hot abyssalite and your oil comes in contact with it, it instantly turns in to petroleum (and then probably sour gas). This is known as "flaking" or "partial melting/evaporation" and is usually the source of much annoyance as you find random puddles or random gas explosions in the oil biome.

But flaking is a powerful tool that allows you to overcome the temperature loss that comes from phase changes. Normally, when you heat crude oil to 403 C, it loses temperature when it boils and becomes 401.5 C petroleum.

Boiling crude oil is exothermic. When 5 kg of crude oil boils using normal boiling at 403 C, it creates 0.22 MDTUs of energy, flaking crude oil creates 1.04 MDTUs (measurements from debug mode, which measures thermal energy based on SHC, mass, and absolute zero). Some of the 0.82 MDTUs of heat can be easily used to heat the crude oil to a higher temperature, allowing you to save heat energy from your heat source. Additionally, with flaking, you don't need to heat the crude all the way to 403 C, allowing you to have the petroleum exit the boiler at a lower temperature.

To demonstrate the benefits, I built two petroleum boilers, one with a flaking boiler and one with a normal boiler. Both have identical counterflow heat exchangers.

The heat source for each of these boilers is a bar of 6 tiles of 1273.1 C steam and the only difference between these. Now for some stats:

1. Crude oil enters each exchanger at 76.9 C.

2. Crude oil enters the top boiler at 378.3 C and the bottom boiler at 375.3 C.

3. Petroleum leaves the top boiler at 403.6 C and the bottom boiler between 379.2 C and 382.8 C

4. Petroleum leaves the top exchanger at 108.2 C and leaves the top exchanger at 106 C.

5. The heat source on the top boiler lost 2708.49 MDTUs and the bottom boiler 2375.24 MDTUs, a 12.3% heat savings.

6. After 10 cycles, each system had about 60000 kg of petroleum.

An interesting thing to note is that the difference in temperature does not account for the difference in heat energy lost. The difference in thermal energy in the petroleum output is only 232 MDTUs, whereas the difference in heat used is 588.2 MDTU. This means that the remaining heat difference is from the heat energy saved from the conversion of 60000 kg of crude oil to petroleum through flaking.

Let's take a closer look at the flaker itself.

This flaker works by heating a tile of ceramic over the boiling point of crude oil.

The crude oil flows in through the liquid vent. It builds up until the tile under the ceramic tile reaches over 5 kg, at which point, it flashes in to petroleum and gets pushed to the left by the remaining crude oil. The petroleum then falls down the escher waterfall.  I use a ceramic tile due to its low thermal conductivity and its accessibility in the mid-game.

I treat the boiler as a contact point for the counterflow heat exchanger, so I maximize heat transfer with bridges.

One thing that is important is that the tile below the flaking liquid should be an airflow tile, as if it is not, the flaked petroleum will sometimes teleport upward and overwrite the steam.

The ceramic block gets its heat from a 1000 kg steam tile, which operates as a heat battery that is maintained (in this case) at 407 C, though it can be kept hotter. To aid in to the transfer of heat to the ceramic tile, there is a vertical conductive conduction panel, conductive wire bridge, conductive automation bridge, and steel shipping rail, all made of aluminum except the conveyor, which is made of steel. The heat is injected through the two doors connected to the heat source.

The liquid shutoff exists to gracefully shut down the crude oil flow if the heat source gets too cold.

The one downside to flaking boilers is that there are hard limits as to how much they can boil at a time.  This design can handle up to 25 kg/s.  Since this boiler runs at 10 kg/s, it is fine that the boiler can't run at full capacity.