Pump & Compressor Applications that Reduce CO2 Emissions
Flue emissions in most power plants or refineries are approximately 67% nitrogen (N2), 20% water (H2O), 10% carbon di-oxide (CO2) and the remaining 2-3% is soot or particulate matter containing sulfur oxides. Removing CO2 from Flue gas is a CCUS (Carbon Capture, Utilization and Storage) application that can be accomplished in many ways – one of which is via Amine Scrubbing. While advanced technologies are still being developed to capture & remove CO2 emissions, Amine scrubbing has been around since the 1930s. It’s a proven process for removing CO2 that is energy-efficient and simple to implement.

How does Amine Scrubbing Work?

Amines are aqueous chemical solvents, such as Monoethanolamine (MEA), Methyldiethanolamine (MDEA) or Diethanolamine (DEA). Amines bond with H2S and CO2 in a way that absorbs & removes them from gas streams. The “scrubbing” process works as follows:
  1. Multi-Stage Gas Compressors move gas into a vapor-liquid separator (called a KO, or knockout drum), which removes water and liquid hydrocarbons from the gas stream.
  2. The untreated “sour” gas moves into the amine absorber. Here, API-610 circulation pumps inject aqueous amine solutions with specific molecules that bind onto CO2 and H2S.
  3. The “rich amine” (now containing the CO2 and H2S) settles at the bottom of the absorber, where it goes to a multi-phase separator. At this point, light hydrocarbons are flashed out of the amine; heavy hydrocarbons are separated from the amine and the rich amine is heated in the lean/rich exchanger, where it is fed to a regenerator column via sealless booster pumps. The pumps used in this process must be capable of supporting extremely high temperatures.
  4. Steam, generated in the reboiler, heats the amine and removes the hydrogen sulfide (H2S) and carbon dioxide (CO2) from the amine.
  5. The lean amine from the regenerator is cooled in an exchanger, where it is returned to the absorber. The H2S is removed from the amine and cooled in an overhead condenser. From there it is sent to sulfur recovery units for processing into sulfur. Similarly, the removed CO2 can be processed into catalysts/polymers that are used to make plastics, adhesives, pharmaceuticals and many other products.
Pump Requirements for Amine Scrubbing Applications
 
Circulation Pumps (Number 2):
Circulation pumps for Amine Scrubbing must comply with API 610 standard. A key requirement is the ability to handle high suction pressures. Reliability is also critical, because amines are corrosive, toxic and dangerous to plant personnel. Simple, streamlined maintenance is a priority, because there are many components on an amine scrubber skid, and access to pumps can be difficult. Price and quick delivery are additional criteria.

Sundyne pumps with a proven track record deployed as Amine Circulation Pumps include:

Marelli KSMK BB2 radially split, centerline mounted centrifugal process pumps (available in one or two stage configurations).

Marelli DVMX, BB3, multi-stage horizontal split case side suction, side discharge process pumps (available in 4-14 stage configurations).

Smaller facilities may prefer Sundyne’s line of LMV Series integrally geared pumps (several models to choose from, depending on flow & pressure requirements). Each member in the LMV family offers superior Low Flow, High Head hydraulics in a compact design with low installed CAPEX.
Booster Pumps (Number 3):

The requirements are similar to those for circulation pumps (API 610 standard, high suction pressure, reliability, etc.). An added requirement is high temperature service. In many instances, sealless pumps are required to ensure leak-free performance. Sealless pumps also save space and reduce maintenance requirements by eliminating seal support systems.

A commonly-deployed Amine Booster Pump is:


HMD Kontro GSP – the General Service Petroleum API 685 (API 610) OH2 Sealless Magnetic Drive Pump offers a range of customized torque ring drives and prime mover specifications to support high temperature operation. Eliminating seals and seal support systems provides leak-free and reliable service, while also lowering installation, maintenance and overall costs.


Regenerator Reflux Pumps (Number 4):

In this stage of the process, liquid hydrocarbons are being pumped at-or-close to bubble points (the phase at which gas bubbles emerge from liquid at a specific temperature). Sealless pumps, made of ETFE or metallic construction are the preferred choices for this application – and two pumps with proven track records for this service include:

ANSIMAG Sealless Magnetic Drive, ETFE Lined Pumps - All of the pump’s wetted parts are made from extremely corrosion resistant materials that safely handle amines without corrosion. A patented, fully encapsulated Mag Drive hermetically seals the inner magnets to isolate them from process fluid and maintain magnet integrity for the life of the unit. Also, an Aramid fiber reinforced containment shell delivers superior burst pressure resistance against water hammer events.

HMD Kontro GS (General Service) sealless magnetic drive pumps are specifically designed for toxic, aggressive, hot or crystallizing processes. The pump’s liquid end can be constructed from several different metallic options, including duplex Stainless Steel, Alloy 20 and Alloy C276.
Compressor Requirements for Amine Scrubbing Applications
 

Feed Gas Compressors (Number 1):

Feed gas compressors move gas through the Amine Scrubber skid and they maintain the operational pressure required for each step in the process. With Amine scrubbing, CO2 and other “sour” impurities in the gas require Stainless Steel or NACE-compliant corrosion-resistant materials. Flash conditions due to numerous heating and cooling processes require high inlet pressures – and high inlet flows require a larger compressor.
Sundyne’s base mounted, multi-stage LF-2000, commonly referred to as a Pinnacle, offers one to six stages of centrifugal compression on a single gearbox. High-head is often required for feed gas applications, and the Pinnacle’s high work impellers help to deliver flows to 10,000 ACFM (17,000 AM³/hr) and maximum working pressures of 5,000 psi (350 bar), making them ideal for this heavy-duty service.

Designed to save space and reduce energy costs, each Pinnacle machine is approximately 25-percent the size of reciprocating, barrel or rotary screw compressors. NACE compliant LF-2000 compressors feature a limited amount of metal that comes in contact with the gas, so they do not rust or corrode. Pinnacle compressors meet API and ISO standards, and they can also be built as non-API, fit for purpose machines, to address different customer needs.
 

Acid Gas Service (Number 5):

Many of the requirements for a feed gas compressor at the beginning of the process also remain for compressors used at the end of the process, to remove acid gas. The primary difference is pressure, and for this service, which requires pressures in the range of 600-1,000 psi (< 70 bar), a single-stage compressor will do.

Sundyne’s BMC Integrally Geared Centrifugal Process Gas Compressors deliver single stage flows up to 3,550 acfm (6,000 AM³/hr), and maximum working pressures up to 1,450 psi (100 bar). Built with NACE-compliant corrosion-resistant materials, BMC compressors can handle acid gas service continuously for up to 5 years without interruption.

Practical and Readily-Available Solutions for Reducing Carbon Footprints Today.

Everyone, in every industry is aware of the need to lower carbon footprints. While new approaches and soon-to-be-developed technologies may one day deliver on the promise of lowering CO2 emissions – existing technologies such as Amine Scrubbing (which has been around for almost 100 years) can be deployed today to eliminate 5-10 percent of the CO2 that comes out of every smokestack, at every power plant, refinery, chemical manufacturer and petrochemical plant.

Amine scrubbing is a proven process. The pumps & compressors used in this service have a long and successful track record. To learn more about additional Sundyne pumps & compressors that can be used in Amine Scrubbing, and other Hydrocarbon processing applications, please visit:

sundyne.com/industries/hydrocarbon-processing-refining
sundyne.com/industries/petrochemical
sundyne.com/industries/power-generation.


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