Compression is a mechanism by which work is put into a fluid to cause an increase in pressure. Heat is also generated as a by-product of compression, which serves to make the process less efficient by turning some of the input work into heat instead of pressure. As the gas being compressed heats up further and further, the compression process gets less and less efficient. Hicor’s technology achieves a more efficient compression process by minimizing the temperature rise associated with compression, improving efficiencies over conventional compressors by 30% or more.

Hicor’s proprietary compression technology provides a myriad of additional benefits as well, including fewer moving parts, less vibration and noise, a variable pressure ratio, and high suction efficiency. It also enables multi-phase compression, which reduces complexity at the wellhead, leads to lower infrastructure costs, and reduces fugitive emissions. Finally, Hicor’s near-isothermal compression technology allows for compression ratios of 30 to 1 or higher, reducing system level complexity and resulting in lower capital and operating costs for producers.

The mathematical basis of a positive displacement compressor is that the work required to compress a gas is equal to pressure times the change in volume. This equation can be integrated to find the work required for a given compression process:

Using this basic equation for work, we can derive the following equation to describe the compression process:

Or more simply:

P = Pressure | V = Volume | γ = Polytropic Constant | 1 = Before Compressing | 2 = After Compressing

The compression process can also be displayed graphically, as in the pressure-volume (PV) plot shown below. The curves in a PV plot show how the pressure increases as volume decreases. For different compression processes, the curves will vary. The work of compression can be visualized as the area under the curve corresponding to a given compression curve.

All compression processes fall between two extremes: adiabatic, where no heat is exchanged with the outside environment and the energy put into the system remains internal; and isothermal, where energy is removed from the system in the form of heat and the temperature of the gas remains constant. In practice, all compression processes fall somewhere between adiabatic and isothermal and are known as polytropic processes. To achieve a more highly efficient compression process, it is ideal to reduce the polytropic constant to as close to the isothermal process as possible, where the polytropic constant is 1.

The Hicor proprietary compressor design is capable of achieving polytropic constants as low as 1.06, improving efficiencies over conventional, near-adiabatic compressors by as much as forty percent.