Natural Gas Liquids (NGL) Recovery & Hydrocarbon Dew Pointing Technology Selection: Mechanical Chilling, Cryogenic Turboexpanders, Joule-Thomson (JT) & Lean Oil Absorption Guide

Executive Summary & Engineering Scope

Raw natural gas extracted from reservoir formations is classified as either dry (lean methane with minimal heavier hydrocarbons) or rich / wet (containing substantial fractions of ethane $\text{C}2\text{H}_6$, propane $\text{C}_3\text{H}_8$, butanes $\text{C}_4\text{H}_5+$ pentanes-plus). }$, and natural gasoline $\text{C

Liquid extraction serves two distinct, non-interchangeable engineering objectives: 1. Hydrocarbon Dew Point (HCDP) Control: Conditioning gas to satisfy pipeline transmission specifications. Pipelines mandate that the cricondentherm of the natural gas phase envelope must remain below maximum operating ground or seabed temperatures (typically $\le -2^\circ\text{C}\text{ to }0^\circ\text{C}$ at $30\text{--}70\text{ barg}$) to prevent retrograde hydrocarbon condensation inside pipelines. 2. NGL Extraction for Economic Value Maximization: Upgrading valuable heavier hydrocarbons into liquid petrochemical feedstocks (Ethane for ethylene crackers; Propane/Butane for LPG heating and transport fuels; Pentanes-plus for refinery blending and diluent for heavy crude transport).

                      NGL PROCESSING PATHWAYS & RECOVERY TARGETS

                              ┌────────────────────────┐
                              │ Raw Conditioned Gas In │
                              └───────────┬────────────┘
                                          │
                  ┌───────────────────────┴───────────────────────┐
                  │ Target Extraction Objective & Gas Richness?    │
                  └───────────────────────┬───────────────────────┘
                                          │
            ┌─────────────────────────────┼─────────────────────────────┐
            │                             │                             │
    [ Dew Point Control ]        [ Propane Recovery (LPG) ]      [ Deep Ethane Recovery ]
     Cricondentherm < 0°C         C3 Recovery > 90-95%            C2 Recovery > 90-95%
     C5+ Knockout Only            C2 Rejection Mode               Ethane Extraction Mode
            │                             │                             │
            v                             v                             v
   Joule-Thomson (JT)             Mechanical Chilling            Cryogenic Turboexpander
     Letdown Plant                (Propane Cycle, -40°C)         (GSP / RSV / ISS, -100°C)

Selecting the appropriate processing scheme requires balancing gas richness (Gallons per Thousand Cubic Feet, GPM), available feed-to-sales pressure drop, sales gas recompression power, product price differentials (the "spark spread" between gas heating value and liquid barrel price), and plant capital expenditure.

This guide provides an engineering evaluation framework comparing: 1. Joule-Thomson (JT) Isenthalpic Expansion Plants 2. Propane Mechanical Refrigeration (Chilling) Plants 3. Cryogenic Turboexpander Plants (GSP, RSV, and ISS Processes) 4. Lean Oil Absorption Plants (Ambient and Refrigerated)

1. Executive Screening Matrix & Rapid Selection Flowchart

The screening choice between JT expansion, mechanical chilling, and cryogenic turboexpanders is governed by Target Hydrocarbon Recovery Level, Feed Gas Richness ($GPM$), Available Pressure Ratio ($P_{\text{in}} / P_{\text{sales}}$), and Plant Gas Capacity.

$$GPM = \sum_{i} \frac{y_i \cdot M_{w,i}}{\rho_{L,i}} \times \frac{1000}{379.482}$$

where $y_i$ is the vapor mole fraction of component $i$, $M_{w,i}$ is molecular weight, and $\rho_{L,i}$ is pure liquid density ($\text{lb/gal}$) per GPA 2145.

The 8-Dimension Technology Decision Matrix

                              RAPID NGL EXTRACTION SELECTION FLOWCHART
                                                 │
                                     What is the target recovery?
                                                 │
                        ┌────────────────────────┴────────────────────────┐
                        │                                                 │
             Ethane Recovery (> 85% C2)?                         Propane or Dew Point Only?
                        │                                                 │
             CRYOGENIC TURBOEXPANDER                                     Is free pressure drop (dP > 35 bar)
                 (GSP / RSV / ISS)                                       available without recompression?
                        │                                                 │
             Requires Mol Sieve (< 0.1 ppmv)                     ┌────────┴────────┐
             Cold Separator: -90°C to -105°C                    YES                NO
                                                                 │                 │
                                                            Joule-Thomson      Mechanical
                                                             (JT) Plant         Chilling
                                                           (MEG Injection)   (Propane Cycle)

2. Feed Contaminant & Operating Boundary Envelopes

Cryogenic and chilled processing envelopes are strictly governed by phase equilibria and physical freeze-out boundaries:

1. Carbon Dioxide Freeze-Out Envelope ($\text{CO}_2$ Solidification)

In cryogenic demethanizer towers and turboexpander cold separators operating below $-60^\circ\text{C}$, carbon dioxide ($\text{CO}_2$) forms solid dry ice: $$\text{CO}_2\text{(vapor)} \rightleftharpoons \text{CO}_2\text{(solid)}$$ Solid $\text{CO}_2$ crystallizes on fractionation trays, packing, and reboiler return lines, causing massive pressure surges and plugging: * In Mechanical Chilling Plants (chilling down to $-35^\circ\text{C}\text{ to }-40^\circ\text{C}$), the liquid hydrocarbon mixture remains safely above the $\text{CO}_2$ freezing threshold. Plants can easily process gas with up to $2.0\text{--}3.0\text{ mol}\% \text{ CO}_2$ without upstream sweetening. * In Cryogenic Turboexpander Plants (temperatures down to $-95^\circ\text{C}$ at $25\text{ barg}$ in the demethanizer overhead), solubility plummets. Inlet $\text{CO}_2$ must be restricted to $\le 0.5\text{--}1.0\text{ mol}\%$ for full ethane rejection mode, or $< 0.2\text{--}0.5\text{ mol}\%$ for deep ethane recovery mode. Higher levels mandate an upstream Amine Acid Gas Removal Unit (AGRU).

2. Moisture and Hydrate Freeze Limits

Water solubility in hydrocarbon vapor drops exponentially with temperature: * At $-40^\circ\text{C}$ (Mechanical Chilling), water solubility is approximately $0.05\text{ lb/MMSCF}$. To prevent hydrate formation inside the gas/gas exchanger and chiller, Monoethylene Glycol (MEG, 70-80 wt%) is sprayed directly onto the tube sheets. Rich MEG and condensed hydrocarbon liquids are separated in a 3-phase cold separator, and the glycol is regenerated and recycled. * At $-100^\circ\text{C}$ (Cryogenic Turboexpander), MEG injection is physically impossible: liquid MEG freezes into a solid glass-like paste at $-15^\circ\text{C}\text{ to }-25^\circ\text{C}$. Therefore, turboexpander plants mandate Molecular Sieve TSA Dehydration Units upstream of the cold section, reducing water to $< 0.1\text{ ppmv}$.

3. Aromatics (BTX) and Heavy Hydrocarbon Freezing

Heavy aromatic compounds—specifically Benzene (freezing point $+5.5^\circ\text{C}$) and p-Xylene—exhibit low solubility in liquid ethane and propane at cryogenic temperatures. In turboexpander plants recovering high ethane, benzene precipitates as solid needles inside the demethanizer column, fouling trays. If feed gas contains more than $100\text{--}250\text{ ppmv}$ benzene, pre-treating with a heavy-hydrocarbon knockout separator or specialized silica gel bed is required.

3. Deep-Dive Process Technology Descriptions & Working Principles

Technology 1: Joule-Thomson (JT) Expansion Plants

The Joule-Thomson process uses simple isenthalpic expansion ($h_1 = h_2$) through a throttling valve to achieve chilling:

                          JOULE-THOMSON (JT) PROCESS FLOW

   High-P Wet Gas ──> [ Gas/Gas Exchanger ] ──> [ JT Valve ] ──> [ Low-T 3-Phase ] ──> Residue Gas (Cold)
                       (Pre-cools feed)         (Throttles dP)     [  Separator  ]
                                                     ^                   │
                                                     │                   v
                                               MEG Injection       NGL to Stabilizer

• Working Principle: High-pressure dry gas ($70\text{--}100\text{ barg}$) is pre-cooled in a shell-and-tube gas/gas exchanger by cross-exchanging with cold residue gas. It then expands through a hardened Joule-Thomson control valve (or throttling orifice) down to sales or gathering pressure ($25\text{--}40\text{ barg}$). The isenthalpic temperature drop is governed by the Joule-Thomson coefficient ($\mu_{JT}$): $$\Delta T = \int_{P_2}^{P_1} \mu_{JT} dP \quad \text{where} \quad \mu_{JT} = \left(\frac{\partial T}{\partial P}\right)_h = \frac{1}{C_p} \left[ T \left(\frac{\partial V}{\partial T}\right)_p - V \right]$$ For typical sweet natural gas, $\mu_{JT} \approx 2.5\text{ to }4.0^\circ\text{C per }10\text{ bar}$ of pressure drop.
• Separation & Hydrate Inhibition: Expanding $80\text{ barg}$ gas to $30\text{ barg}$ produces an expansion cooling drop of $15\text{--}22^\circ\text{C}$, yielding a separator temperature of $-15^\circ\text{C}\text{ to }-25^\circ\text{C}$. Condensed heavy hydrocarbons ($\text{C}_5+$ and some $\text{C}_3/\text{C}_4$) drop out in the cold separator. Hydrates are suppressed by continuously atomizing an 80 wt% MEG solution onto the exchanger tube sheet upstream of the JT valve.
• Limitations: The process is entirely dependent on having free wellhead pressure that must be dissipated. If the sales pipeline operates at high pressure, compressing residue gas consumes immense recompression horsepower, destroying process economics.

Technology 2: Propane Mechanical Refrigeration (Chilling) Plants

When wellhead pressure cannot be wasted, an external closed-loop mechanical refrigeration cycle provides heat extraction:

                   PROPANE MECHANICAL REFRIGERATION FLOW

    High-P Feed ──> [ Gas/Gas Exchanger ] ──> [ Gas Chiller (Evaporator) ] ──> [ Cold Separator ] ──> Sales Gas
                                                     │                               │
                                                     │ Heat Exchange                 v
                                                     v (C3 Boils at -40°C)       NGL Liquids
                                            ┌──────────────────┐
                                            │ Refrigeration    │ ──> [ Aerial Condenser ]
                                            │ Compressor Skid  │ <── [ Liquid Receiver  ]
                                            └──────────────────┘

• Working Principle: Process gas is chilled in a shell-and-tube kettle evaporator (gas chiller) where liquid propane refrigerant boils at $-35^\circ\text{C}\text{ to }-40^\circ\text{C}$ on the shell side under low pressure ($1.05\text{--}1.30\text{ bara}$). Evaporated propane vapor is drawn into a centrifugal or reciprocating refrigeration compressor, compressed to $12\text{--}16\text{ bara}$, condensed against ambient air in fin-fan coolers, and expanded across a thermostatic expansion valve back into the chiller.
• Recovery Envelope: Operating the cold separator at $-35^\circ\text{C}$ to $-38^\circ\text{C}$ condenses virtually all pentanes-plus ($\text{C}_5+ > 98\%$), the majority of butanes ($\text{C}_4 \approx 85\text{--}92\%$), and a significant fraction of propane ($\text{C}_3 \approx 70\text{--}85\%$). Ethane recovery is minimal ($< 5\text{--}10\%$), making mechanical chilling the optimal choice for LPG (Propane + Butane) recovery while avoiding the extreme complexity of cryogenic metallurgy.
• Dehydration Architecture: Upstream gas is either dehydrated via an inlet TEG contactor designed for low water dew points (with stripping gas), or inhibited via MEG injection directly into the chiller tubes.

Technology 3: Cryogenic Turboexpander Plants (GSP / RSV Schemes)

When project economics dictate deep ethane extraction ($> 90\%\text{ C}_2$ recovery) or high propane extraction from lean gas, Cryogenic Turboexpander plants represent the industry pinnacle:

                CRYOGENIC TURBOEXPANDER FLOW SCHEME (GSP)

   Dry Feed ──> [ Cold Box Heat ] ──> [ Cold Separator ] ──> Vapor ──> [ Turboexpander ] ──> Demethanizer Top
   (<0.1 ppm)   [   Exchangers  ]     (Flash @ -60°C)         │        (Spins 30,000 RPM,     (-95°C, 25 bar)
                                                              │         Drops T to -100°C)          │
                                                              v Liquid                              v
                                                      [ Side Reboilers ]                    Demethanizer Bottoms
                                                      (Exchanges Cold)                      (NGL Ethane + Heavy)

• Working Principle (Isentropic Expansion): Unlike isenthalpic throttling across a JT valve, a turboexpander extracts mechanical work from expanding gas through an aerodynamic turbine wheel: $$W_{\text{shaft}} = \dot{m} \cdot \left( h_1 - h_2 \right) = \dot{m} \cdot C_p T_1 \left[ 1 - \left(\frac{P_2}{P_1}\right)^{\frac{\gamma - 1}{\gamma}} \right] \cdot \eta_{\text{isen}}$$ Because enthalpy is converted into shaft work, isentropic temperature drops are $3\times\text{ to }5\times$ greater than JT letdown ($\Delta T = 40^\circ\text{C}\text{ to }70^\circ\text{C}$). Cold separator temperatures reach $-90^\circ\text{C}\text{ to }-105^\circ\text{C}$.
• Shaft Power Recovery: The high-speed turbine shaft is rigidly coupled to a direct-driven centrifugal booster compressor. The recovered shaft power compresses the warm residue gas, recovering $40\%\text{--}60\%$ of the initial pressure drop and significantly reducing downstream electric/gas turbine recompression duty.
• Advanced Cryogenic Schematics:
• Gas Subcooled Process (GSP): A slipstream of high-pressure vapor from the cold separator is subcooled and condensed against demethanizer overhead vapor and flashed into the top of the demethanizer as an ultra-pure liquid methane reflux stream. This cold reflux scrubs out stripped ethane molecules, boosting $\text{C}_2$ recovery from $75\%$ to $90\text{--}95\%$.
• Recycle Split-Vapor (RSV): Compresses a portion of the residue gas, chills it, and injects it as high-purity methane reflux into the column top, achieving $> 98\%$ ethane recovery even on lean feeds.

Technology 4: Lean Oil Absorption Plants

The historical standard prior to the invention of the turboexpander in the 1960s, lean oil absorption uses high-boiling hydrocarbon solvents: * Working Principle: Raw gas is scrubbed counter-currently in a high-pressure absorber column ($40\text{--}70\text{ barg}$) against a circulating stream of lean absorption oil (typically kerosene or naphtha with molecular weights of $100\text{--}140\text{ g/mol}$). Liquid hydrocarbons dissolve into the oil per Henry's Law. Rich oil is flashed, heated, and stripped in a distillation train to separate recovered NGLs and regenerate lean oil. * Modern Status: Refrigerating lean oil to $-20^\circ\text{C}$ to $-35^\circ\text{C}$ improves propane recovery ($85\%\text{ C}_3$). However, lean oil plants have been largely displaced in greenfield developments by turboexpanders due to high oil circulation pumping energy, heavy oil vaporization losses into sales gas, and complex multi-column fractionation trains.

4. Utility, Consumables & Parasitic Power Intensities

NGL recovery processes demand vast amounts of mechanical compression power and fractionation reboiler duty. Evaluating parasitic power intensity is the primary economic selection criterion:

Mechanical Compression Power Formulation

Residue gas leaving a cryogenic or JT plant must be recompressed to pipeline transmission pressure ($70\text{--}100\text{ barg}$):

$$P_{\text{recomp}} = \frac{1}{\eta_{\text{comp}}} \cdot \frac{k}{k-1} \cdot \frac{Z_{\text{avg}} R T_{\text{suct}}}{M_w} \cdot \dot{m} \cdot \left[ \left(\frac{P_{\text{sales}}}{P_{\text{exp}}}\right)^{\frac{k-1}{k}} - 1 \right]$$

For turboexpander units, the net compressor drive power is discounted by the shaft work generated by the expander wheel:

$$P_{\text{motor/turbine,net}} = P_{\text{recomp,total}} - \left( W_{\text{expander}} \cdot \eta_{\text{mech}} \right)$$

Utility Comparison Benchmark Table (100 MMSCFD Plant)

5. CAPEX vs. OPEX Economic Trade-Offs (Lifecycle Cost Modeling)

The financial decision between simple chilling and deep cryogenic extraction is dictated by the NGL Spark Spread:

$$\text{Spark Spread} = \text{Market Value of Recovered Liquids (\$/bbl)} - \text{Equivalent Heating Value of Shrinkage Gas (\$/MMBTU)}$$

                   NGL RECOVERY LIFECYCLE TRADE-OFF (100 MMSCFD)

      CAPEX ────────────────────────────────────────────────────────┐
      Joule-Thomson / Chilling: Carbon steel + Shell/Tube Exchangers│ Chilling Wins on Initial CAPEX
      Cryogenic Expander: Cold box (BAHX) + Stainless + Demethanizer│ ($18M vs $52M)
                                                                    │
      REVENUE ──────────────────────────────────────────────────────┤
      Joule-Thomson / Chilling: C3+ recovery only (~1,800 BPD)      │ Expander Wins Massive Revenue
      Cryogenic Expander: Deep C2+ recovery (~4,200 BPD)            │ (+$25M to $45M / year)

Capital Expenditure (CAPEX) Drivers

1. Metallurgy & Brazed Aluminum Heat Exchangers (BAHX): Mechanical chilling units operate at $-40^\circ\text{C}$, permitting standard impact-tested low-temperature carbon steel (LTCS, ASTM A333 Grade 6) and conventional shell-and-tube exchangers. Turboexpander plants drop to $-105^\circ\text{C}$, mandating austenitic stainless steel (SS304/SS316) piping and core brazed aluminum plate-fin heat exchangers (BAHX / cold boxes) fabricated in specialized vacuum braze furnaces.
2. Dehydration Pre-Treatment: Chilling units utilize low-cost MEG injection or standard TEG dehydration. Turboexpanders require multi-bed molecular sieve dehydration systems ($3\times$ CAPEX of TEG) and heavy dust filtration units to protect high-speed expander impellers.

Operating Revenue & Volumetric Shrinkage

• Extracting ethane shrinks the gas volume and reduces the gross heating value (GHV) of sales gas. When ethane petrochemical prices are high, recovering ethane yields massive revenue premiums ($+\$30\text{M/year}$ on a $100\text{ MMSCFD}$ plant).
• However, when ethane prices drop to parity with natural gas on an energy basis, plants must operate in Ethane Rejection Mode: rejecting ethane back into the sales gas while maintaining high propane recovery ($> 95\%\text{ C}_3$). Cryogenic turboexpander plants (GSP/RSV) can switch seamlessly between ethane recovery and rejection via column pressure and reboiler control; mechanical chilling plants can never recover ethane.

6. Operational Constraints, Turn-Down Ratios & Reliability Profiles

1. High-Speed Rotating Machinery (Turboexpander vs. Chilling)

• Turboexpanders: Expanders operate on magnetic bearings or pressurized oil bearings at speeds between $20,000\text{ and }50,000\text{ RPM}$. They are sensitive to liquid droplet carryover (which causes supersonic blade erosion) and sudden pressure surges. Mean time between maintenance overhauls is typically $25,000\text{ to }35,000\text{ hours}$.
• Mechanical Refrigeration: Propane compressors use proven industrial screw or centrifugal designs operating at standard speeds ($1,500\text{--}3,600\text{ RPM}$) with mechanical availabilities exceeding $98.5\%$.

2. Turndown Capability

• Turboexpander Plants: Turndown is achieved using variable inlet guide vanes (IGVs) on the expander nozzle. Modern IGVs allow efficient operation down to $50\%\text{--}60\%$ of design throughput. Operating below $45\%$ causes expander efficiency to drop sharply, requiring bypass through a Joule-Thomson valve with severe loss in liquid recovery.
• Mechanical Chilling Plants: Highly flexible turndown ($20\%\text{ to }110\%$) using compressor slide valves (for screw compressors) or speed control / suction throttling (for centrifugal units).

7. Environmental Footprint, Methane Slippage & Carbon / ESG Compliance

                           CARBON & EMISSIONS PROFILE

   [ Cryogenic Turboexpander Plant ]            [ Propane Mechanical Chilling Plant ]
   - High recompression driver power (MW)       - Propane refrigeration fugitive leakage
   - High demethanizer reboiler thermal duty    - Refrigeration compressor engine exhaust
   - Zero routine flaring in steady state       - Fugitive MEG flash gas venting
   Carbon Intensity: 22-38 kg CO2e/BOE          Carbon Intensity: 15-28 kg CO2e/BOE

1. Refrigerant Fugitive Losses: Propane chilling systems contain thousands of kilograms of flammable volatile hydrocarbon refrigerant. Fugitive emissions from compressor shaft seals, valve packings, and pressure relief valves represent continuous VOC losses that must be monitored under EPA Method 21 leak detection and repair (LDAR) regulations.
2. Compressor Driver Decarbonization: Residue gas recompression drives represent the single largest carbon emission source in gas processing plants. Transitioning from gas-fired turbines to high-efficiency electric motor drives powered by grid or renewable power reduces Scope 1 emissions by over $65\%$.

8. Real-World Selection Case Study with Sensitivity Analysis

Field Development Scenario: 200 MMSCFD Rich Shale Gas Processing

An operator is designing a central gas processing facility for a newly developed liquids-rich shale play: * Gas Flow Rate: $200.0\text{ MMSCFD}$ ($5.66 \times 10^6\text{ Sm}^3/\text{d}$) * Inlet Pressure at Plant Boundary: $72.0\text{ barg}$ ($1,044\text{ psia}$) * Inlet Temperature: $32.0^\circ\text{C}$ * Sales Gas Delivery Pressure: $65.0\text{ barg}$ ($942\text{ psia}$) * Feed Gas Composition (Rich Gas, $GPM = 4.45$): * $\text{Methane (C}_1)$: $78.5\text{ mol}\%$ * $\text{Ethane (C}_2)$: $11.2\text{ mol}\%$ ($GPM = 2.99$) * $\text{Propane (C}_3)$: $5.4\text{ mol}\%$ ($GPM = 1.48$) * $\text{Butanes (iC}_4 + \text{nC}_4)$: $2.6\text{ mol}\%$ ($GPM = 0.83$) * $\text{Pentanes-Plus (C}_5+)$: $1.1\text{ mol}\%$ ($GPM = 0.40$) * $\text{Carbon Dioxide (CO}_2)$: $0.8\text{ mol}\%$ * $\text{Nitrogen (N}_2)$: $0.4\text{ mol}\%$

Candidate Processing Schemes Evaluated

Option A: Joule-Thomson (JT) Expansion Plant
          - Flashes feed from 72 bar to 35 bar; recompresses sales gas to 65 bar
          - Cold separator @ -20°C with MEG injection

Option B: Mechanical Propane Refrigeration Chilling Plant
          - Closed-loop propane cycle chilling gas to -38°C; separator @ -35°C
          - Minimal feed pressure drop; zero residue recompression

Option C: Cryogenic Turboexpander Plant (GSP Process)
          - Molecular Sieve TSA pre-treatment (< 0.1 ppmv H2O)
          - Expands gas across turboexpander to 28 bar; cold separator @ -95°C
          - Recompresses residue gas to 65 bar using expander brake + 14 MW sales booster

Quantitative Comparative Evaluation Matrix

Engineering Decision Rationale & Sensitivity Outcome

1. The Selection Winner: Option C (Cryogenic Turboexpander Plant).
2. Although Option C requires the highest initial capital investment ($\$88.5\text{M}$ vs $\$46.2\text{M}$ for mechanical chilling), it delivers an additional $7,550\text{ BPD}$ of high-value natural gas liquids, primarily through $92.5\%$ recovery of ethane.
3. At standard midstream NGL basket pricing ($\$42/\text{bbl}$ NGL composite vs $\$3.20/\text{MMBTU}$ residue gas value), the incremental annual cash flow is $\$47.6\text{M/year}$, paying out the incremental $\$42.3\text{M}$ CAPEX in just $10.6\text{ months}$.
4. Why Option A (JT Plant) Lost: Because sales gas must be delivered at $65.0\text{ barg}$, expanding gas down to $35\text{ barg}$ across a JT valve destroys pressure that must immediately be re-supplied by an expensive $9.5\text{ MW}$ reciprocating recompressor. The process yields poor liquid recovery ($2,150\text{ BPD}$) while incurring high compression costs.
5. Ethane Rejection Flexibility: During market downturns when ethane price drops below fuel value, the GSP turboexpander plant can be switched to Ethane Rejection Mode in less than 2 hours by warming the demethanizer bottom and reducing column reflux, rejecting $95\%$ of ethane into sales gas while maintaining $> 96\%$ propane recovery.

9. Integration with ChemProCal Engineering Tools

To rigorously model NGL extraction, hydrocarbon dew points, and refrigeration cycles, utilize these integrated ChemProCal calculators:

• NGL Recovery, Gas Shrinkage & Condensate Stabilizer Sizer: Calculate component liquid recovery rates (GPM), plant gas volumetric and thermal shrinkage, and size condensate stabilizer columns to meet RVP vapor pressure limits.
• Natural Gas Mixture Phase Envelope Explorer (PR-EOS): Plot full Peng-Robinson multicomponent phase envelopes, evaluate cricondentherm and cricondenbar coordinates, and verify pipeline hydrocarbon dew point margins.
• Gas Condensate Multi-Stage Flash Pressure Optimizer: Optimize intermediate flash separator pressures, maximize stock-tank liquid yields, and minimize stabilization recompression horsepower.
• Centrifugal Compressor Performance Map: Model residue gas recompression stages and refrigeration loop compressors per API 617.