CO2 elimination

This article will describe ways to get rid of carbon dioxide (hereafter CO2).

Dupes consume 100 g/s of oxygen and emit 2 g/s of CO2. A colony of 3 dupes emits 3.6 kg of CO2 in 1 cycle and if left unchecked, this can be a problem.

Almost all gases in the game are heavier than oxygen, and most tricks will help in getting rid of any other gases (chlorine, natural gas, etc.). Hydrogen is lighter than the others, and it usually doesn't get in the way as it accumulates at the very top of the base.

The order of the steps is from simple to complex. .

Pit



 * Simplicity and accessibility from the start


 * This method is enough for 15...30 cycles.

First, dig a passage down to the cavity with oxygen or vacuum. The CO2 will start to go down, which will solve the problem for a while.

The cavity shown in the screenshot has a volume of 50 cells, which at normal base oxygen pressure, gives a capacity of about 90 kg of CO2. Since 3 dupes exhale 3.6 kg/cycle, this method will work for 25 cycles.

Later on, in the same place, you can build one of the following schemes.

Algae Terrarium



 * Produces oxygen (18 farms are needed for 3 dupes) and polluted water, 3135 kg/cycle


 * Consumes water, 3240 kg/cycle and algae, 324 kg/cycle
 * Requires the work of dupes to empty terrariums

One terrarium destroys 0.33 g/s of CO2. It would take 18 terrariums for 3 dupes. At the same time, 8 terrariums are sufficient to provide oxygen for 3 dupes.

Each terrarium consumes 300 g/s of water, and its total consumption would be 3.2 tons/cycle, which is a lot, plus 324 kg/cycle of algae.

On the merits is the production of polluted water, which can be used to produce polluted oxygen. In the presence of lighting works by 10% more efficient (less farms will be needed). The scheme was discussed here.

Oxyfern

 * Produces oxygen


 * Consumes water, 19 kg/cycle and dirt, 4 kg/cycle
 * Requires the work of dupes (feeding) or delivery by auto-sweeper


 * Grows in a forest biome, which not all asteroids have

Oxyfern removes 0.625 g/s of CO2 and produces 31.25 g/s of oxygen, in the proportions just needed by dupes.For a colony of 3 doubles, you would need 10 farms. The automation option was considered here.

Pump



 * Does not require the participation of dupes
 * Lets you save the CO2 (e.g., for a slickster farm)
 * Suitable for other interfering gases


 * Consumes energy
 * Requires automation

The gas sensor detects oxygen, the NOT-gate inverts the signal, and the filter prevents accidental gases from triggering (a single cube of CO2 falling down).

The circuit is also suitable for other gases. All of them are not destroyed but only transported forward. Then they can be filtered out and used: CO2 to slickster, natural gas to generators, etc.

Destruction and storage



 * There are advantages and disadvantages

The gases pumped out can (from left to right):


 * 1) Dumped into space. If you're sure you don't need the gases, that's the easiest and most trouble-free option.
 * 2) Place in a Gas reservoir. For a colony of 3 dupes, there's only enough capacity for 24 cycles.
 * 3) Place in a compressor (infinite storage). There is a limit of no more than 2 types of gas. A pump is needed in case you decide to use this gas
 * 4) Manually empty the pipe into the canisters (requires a dupe with plumber's skill). Hand work and a way to dispose of it later will be needed. Temporary measure.
 * 5) Place in a very cold biome. At temperatures below -48.1°C (actually even lower), the CO2 will become liquid and can be stored compactly. I haven't come across biomes like this, but maybe there are

Door Destroyer



 * Doesn't consume anything
 * Doesn't require the participation of dupes


 * Requires automation

If there is a CO2 near the sensor, the doors will periodically open and close. Gas trapped by the upper door, will be destroyed when the lower door closes.

Settings:
 * Gas sensor: CO2.
 * Timer: 5 green, 5 red
 * Buffer: 1.5s (delays closing the bottom door)

The circuit can be slightly reconfigured to eliminate any gases as it is done in the pump circuit (add a NOT-gate).

Carbon Skimmer



 * Huge output -300 g/s CO2
 * Low circuit consumption (in terms of 3 dupes)


 * Produces polluted dirt
 * Requires the work of dupes or delivery by auto-sweeper


 * Together with a Water sieve, consumes 144 watts and 200 g/s sand or regolith

If the goal is to destroy CO2 in large volumes - this is the best solution. It can be used without water sieve (and without sand accordingly), obtaining polluted water, which can then be turned into oxygen.

Algae terrarium (exploit)



 * Infinite storage
 * Almost free


 * There is a risk of depressurization

In the scheme shown in the screenshot, the algae terrarium moves the CO2 into the airflow tile. There it will accumulate in huge quantities, which can be a problem if you want to rebuild the circuit or accidentally wipe the water over/under that tile.

If you want to disassemble this circuit, you'll have to complete the chamber, pump, and airlock and pump all the CO2 elsewhere (however, the same will be required with the compressor).

Door compressor



 * Let's keep the CO2


 * Some difficulty to build

The door compressor allows you to pump gases (and liquids) quickly and without energy expenditure. If you don't need these gases later on, you don't need to build the pump.

The left buffer serves to protect against false triggers from accidental gases. As with the destroyer version, you can modify the scheme for any gases. Gate settings (left to right): 30, 7, 6, 7, 8, 5, 2 s.

Cluster pump



 * Huge capacity (at high pressures)
 * Let's keep the CO2


 * Complicated to build, bulky

For very fast pumping of gases (not only CO2), this cluster pump can be used. For high gas pressures, it is faster and more economical than a conventional pump.

It does not make much sense to use it for CO2.

Valve 50 g, under vent 100 g of crude oil, petroleum, etc.

Soda Fountain
The way PigsAreBest reminded me of.

The Soda fountain consumes 1 kg of carbon per application, which is close to the carbon emission of a dupe per cycle. The requirements of the fountain are high: location in the rest room, a water pipe, and a consumption of 480 watts. Gives a +4 to morale.

Slickster



 * Provide crude oil from UG


 * Requires the participation of dupes

The Slickster farm allows you to feed them CO2 and get crude oil (50% of what's consumed). The screenshot shows a simple variant that allows you to maintain the farm without atmosuits.

The scheme should be placed at the very bottom, above the oil lakes. This will provide both a supply of CO2 (top and side) and an optimum temperature for slickster (50 ... 140°C).

You should take care to maintain this temperature (it is enough to add a Space heater with a sensor). If it will be lower than 50°C - chance of having useless longhair slickster, which consume oxygen and give decorations. If the temperature is much higher - it will be impossible to maintain the farm without atmosuits.

The farm is exactly 96 cages in size, which is enough to house 8 critter, each capable of consuming 20 kg/cycle of CO2 or 160 kg/cycle for the entire farm, who will give 80 kg/cycle of crude oil.

Excess critter or their eggs can be let into the kitchen, which will also give extra calories.

Molten Slickster



 * Perform petroleum from CO2


 * Requires the participation of dupes
 * Requires automatics and power

Same as the scheme above, but providing petroleum at the output, in much larger quantities. The Molten Slickster was discussed in detail here.