Neqsim Compressor Antisurge Recycle

What it does

When your agent uses it

• : a task must protect a compressor from surge
• Coordinate speed and recycle valve at minimum speed
• Stop uncoordinated recycle opening
• Value power/CO2 savings from control optimization

Example prompts

• “/neqsim-compressor-antisurge-recycle”

Requirements

• Python 3

Workflow steps

7 steps, taken from the first numbered list in SKILL.md.

1. 1Split-Range Output Transition: Pressure controller output is divided at a configurable transition (e.g., 75%).
2. 2Speed Command Range: Above transition (75% to 105%), recycle addition is zero and compressor speed increases linearly from minimum (75%)…
3. 3Inverse Recycle Addition: Below transition (0% to 75%), speed is held at minimum (75%) while an inverse recycle addition increases as…
4. 4Latch on Entry: On lower-range entry, the previously selected recycle command is latched and pressure-derived recycle is added to that…
5. 5High Selector Protection: Independent anti-surge and suction-pressure demands participate in a high selector ($R_{selected} =…
6. 6Unwind before Speed Increase: On rising pressure, pressure-derived recycle unwinds to the latched baseline before speed increases.
7. 7Dynamic Saturation Floor: Applies a lower output limit (latched * 74 / 100) to prevent integral windup.

What it can do on your machine

Read from SKILL.md and the folder at commit 69c5882. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  No scripts in the folder and no shell commands in SKILL.md (its code samples are java and python).

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  No URLs in SKILL.md.

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Neqsim Compressor Antisurge Recycle loads about 2k tokens when it runs. Until then it costs about 118 tokens; SKILL.md has 571 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~118

When it runs · the whole SKILL.md, loaded when a task matches

~2k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from equinor/neqsim at commit 69c5882, republished under its Apache-2.0 licence (© equinor). 571 words, ~2,031 tokens.

name

neqsim-compressor-antisurge-recycle

description

Anti-surge recycle and coordinated minimum-speed recycle control for centrifugal compressors in NeqSim: chart generation, anti-surge calculation, MinimumSpeedRecycleControllerStructure split-range control, fuel-gas, CO2 and cost savings. USE WHEN: a task must protect a compressor from surge, coordinate speed and recycle valve at minimum speed, stop uncoordinated recycle opening, or value power/CO2 savings from control optimization.

version

1.0.0

last_verified

2026-08-26

requires.java_packages

neqsim.process.equipment.compressor, neqsim.process.controllerdevice.structure, neqsim.process.controllerdevice

import neqsim.process.controllerdevice.ControllerDeviceInterface;
import neqsim.process.controllerdevice.ControllerDeviceBaseClass;
import neqsim.process.controllerdevice.structure.MinimumSpeedRecycleControllerStructure;

// Create controllers
ControllerDeviceInterface pressureController = new ControllerDeviceBaseClass("PIC-0205A");
ControllerDeviceInterface antiSurgeController = new ControllerDeviceBaseClass("UIC-0231");
ControllerDeviceInterface suctionController = new ControllerDeviceBaseClass("PIC-0131");

// Instantiate structure: (pressureCtrl, antiSurgeCtrl, suctionCtrl, transitionPct, maxOutputPct, minSpeedPct, maxSpeedPct)
MinimumSpeedRecycleControllerStructure coordStructure = new MinimumSpeedRecycleControllerStructure(
    pressureController, antiSurgeController, suctionController, 75.0, 105.0, 75.0, 100.0
);

// In transient loop or update step:
coordStructure.update(pressureControllerOutput, antiSurgeOutput, suctionPressureOutput);

double speedCommand = coordStructure.getSpeedOutput();             // % speed
double recycleAddition = coordStructure.getRecycleAddition();       // % recycle addition
double recycleCommand = coordStructure.getLatchedRecycleOutput();   // % latched baseline

from neqsim import jneqsim

# 1. Fluid Creation
fluid = jneqsim.thermo.system.SystemSrkEos(311.15, 12.5) # 38 °C, 12.5 bara
fluid.addComponent("methane", 0.78)
fluid.addComponent("ethane", 0.085)
fluid.addComponent("propane", 0.045)
fluid.addComponent("CO2", 0.040)
fluid.setMixingRule("classic")

# 2. Recompressor Model
stream = jneqsim.process.equipment.stream.Stream("Suction Gas", fluid)
stream.setFlowRate(150000.0, "kg/hr") # 150 t/h net flow
stream.run()

comp = jneqsim.process.equipment.compressor.Compressor("Recompressor", stream)
comp.setOutletPressure(45.0, "bara")
comp.setPolytropicEfficiency(0.78)
comp.setUsePolytropicCalc(True)
comp.run()

base_power_kw = comp.getPower() / 1000.0

# 3. Recycle Sweep
for r_frac in [0.0, 0.10, 0.20, 0.30]:
    total_flow = 150000.0 / (1.0 - r_frac)
    stream.setFlowRate(total_flow, "kg/hr")
    stream.run()
    comp.run()
    p_kw = comp.getPower() / 1000.0
    extra_kw = p_kw - base_power_kw
    extra_co2_t_hr = (extra_kw / (0.34 * 48000.0)) * 3600.0 * 2.75 / 1000.0
    print(f"Recycle {r_frac*100:.0f}%: Power = {p_kw:.1f} kW (+{extra_kw:.1f} kW), Extra CO2 = +{extra_co2_t_hr:.2f} t/h")

© equinor, Apache-2.0. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

Just SKILL.md in .github/skills/neqsim-compressor-antisurge-recycle of equinor/neqsim.

Open the folder on GitHubat commit 69c5882