Industrial Solvent Recovery Systems Frequently Used in O&G
May 28, 2019 Welcome
Oilfield operators looking to thrive in this competitive industry must continuously seek ways to optimize their processes in an environmentally-conscious and economic manner. This article will introduce some effective techniques for improving solvent recovery at your facility.
What Is Solvent Recovery?
Industrial solvent recovery is the process of extracting useful solvents from a process waste stream. In the oil and gas industry, industrial-scale distillation is the major technique for recovering solvents, useful chemical components, and petrochemical feedstock from hydrocarbon mixtures. For example, extracting hydrocarbon oils from petroleum sludge in a solvent recovery unit.
By recycling useful process inputs for reuse, solvent recovery helps operators shave off costs for procuring new solvents/raw materials and waste disposal. Additionally, operators can improve their operational safety and efficiency and ensure compliance with provisions from environmental regulatory authorities such as the EPA.
Types of Solvent Recovery Systems
A solvent recovery system is a technological solution for extracting useful solvents and raw materials from industrial effluents via various techniques. When used efficiently, solvent recovery techniques can recover up to 80% of useful solvents and raw materials in high-purity from process waste. Many operators utilize modular process skids with semi-continuous operation for the solvent recovery process.
Applications of Industrial Solvent Recovery Systems
Industrial solvent recovery systems are used in a host of industrial applications including:
- Crude oil refining
- Purification of petrochemicals
- Pharmaceuticals manufacturing
- Hazardous/Non-hazardous chemicals manufacturing
Below are the major solvent recovery systems employed in the oil and gas industry:
Membrane separation utilizes a low-permeability and high-sensitivity membrane to separate reusable solvents from petrochemical process waste materials. Some common applications are for removing methane, CO2, and water vapor from natural gas and in desalination of produced water (Brine). Membrane filtration systems come in a variety of pore sizes which impact their efficiency. Typical ranges are from 1000 to 0.0001 microns.
Recovery Using Coalescers
Coalescer systems are used to separate the components of fluid mixtures via coalescence. Coalescence is the coming together (agglomeration) of molecules to form a larger whole. Coalescers are applicable in onshore/offshore oil and gas facilities and chemical plants where they are used for fuel-gas, water-gas, and gas-oil separation.
The mode of operation is either electrical (where small AC/DC charges are used to induce droplet coalescence in the fluid mixture) or mechanical (using a series of baffle walls or screens and microfiber filters to separate the individual components based on specific properties such as molecular weight and density).
Recovery via Adsorption
In fluid absorption, the recovery medium is an adsorbent material which inhibits one substance while based on a specific physical property. The principle of operation is that some components of a mixture exhibit a strong affinity for certain adsorbent materials.
Adsorbent recovery is useful for separating the components of feed gas mixtures, in the dehumidification of ‘wet gas,’ and for oil spill cleanup, etc. Applications in the Oil and Gas Industry include the use of Silica gel or Alumina to remove inorganic solutes from natural gas streams and molecular sieves for denitrification. In industrial facilities, Granular Activated Carbon (GAC) is used to remove organic compounds such as lignite and coal particles from industrial wastewater.
The distillation process is carried out in a solvent recovery unit consisting of large distillation vessels and jacketed tanks which separate the various components of a feed mixture in batches, or on a continuous basis. The working principle is that each component will be distilled from the unit at various points based on its unique boiling point or chemical composition.
Solvent Distillation Process
The distillation recovery process typically involves the following steps:
- The liquid mixture is introduced into the distillation vessel and heat is applied.
- As the mixture warms, the component fractions with lower boiling points vaporize and rise to the top of the vessel.
- As the lighter fractions rise to the top of the unit, the heavier particles condense and fall back to the bottom. Efficient solvent recovery plant design allows for solute components to be collected at distinct levels or ‘stages’ within the distillation unit.
- The vapors collected at the top of the unit and condensed in industrial chillers.
- The products of the distillation process are recirculated in the system until the required degree of purity is obtained.
In crude oil distillation, the short-chain gaseous hydrocarbons with lower boiling points (e.g., Ethanol at 78.37 °C) rise to the top of the unit, while the heavier fractions (such as heavy oils at 175°C–600 °C) are tapped off at the bottom.
See How IFS Can Support Your Solvent Recovery Needs
Integrated Flow Solutions specializes in the design and fabrication of modular process systems. Our experienced professionals can help design the ideal solvent recovery system and provide cost-effective recovery equipment and maintenance services tailored to your needs.