Insert kits for multi-stage compressors and associated systems, processes and methods

An insert kit for converting an internal combustion engine to a multi-stage compressor, the insert kit comprising:

• a first insert having a first inside diameter and configured to be positioned at least partially within a first compression cylinder of the engine to reduce the volume of the first compression cylinder by a first amount, wherein the first insert comprises a thermally conductive inner annular cylinder made of a first material and a thermally insulative outer annular cylinder made of a second material different from the first material and at least partially encircling the inner annular cylinder;
• a directing fin coupled to the first insert, wherein the directing fin is configured to induce a swirl to a gas injected into the first compression cylinder;
• a coolant channel within the first insert, wherein the coolant channel is configured to cool the gas, and wherein the directing fin and the coolant channel operate to stratify the gas such that a first portion of the gas positioned toward the center of the first insert is at a first temperature, and a second portion of the gas positioned radially outward from the first portion is at a second temperature, higher than the first temperature;
• a second insert having a second inside diameter, smaller than the first inside diameter, and configured to be positioned at least partially within a second compression cylinder of the engine to reduce the volume of the second compression cylinder by a second amount, greater than the first amount;
• a first compression piston configured to be positioned within the first insert to compress the gas to a first gas volume;
• a second compression piston configured to be positioned within the second insert to compress the gas to a second gas volume, smaller than the first gas volume;
• and
• a production line for producing compressed gas, the production line including one or more conduits positioned to transport compressed gas between the first insert and the second insert.