diff --git a/src/main/java/neqsim/processSimulation/processEquipment/separator/Separator.java b/src/main/java/neqsim/processSimulation/processEquipment/separator/Separator.java
index e1a9448031..5d785b0241 100644
--- a/src/main/java/neqsim/processSimulation/processEquipment/separator/Separator.java
+++ b/src/main/java/neqsim/processSimulation/processEquipment/separator/Separator.java
@@ -302,7 +302,10 @@ public void runTransient(double dt, UUID id) {
     // double liqoutMoles = liquidOutStream.getThermoSystem().getNumberOfMoles();
     thermoSystem.init(3);
     gasOutStream.getThermoSystem().init(3);
-    liquidOutStream.getThermoSystem().init(3);
+    if (liquidOutStream.getThermoSystem().hasPhaseType("oil")) {
+      liquidOutStream.getThermoSystem().init(3);
+    }
+
     double volume1 = thermoSystem.getVolume();
     // System.out.println("volume1 " + volume1);
     double deltaEnergy = inletStreamMixer.getOutletStream().getThermoSystem().getEnthalpy()
diff --git a/src/test/java/neqsim/processSimulation/processSystem/ProcessSystemRunTransientTest.java b/src/test/java/neqsim/processSimulation/processSystem/ProcessSystemRunTransientTest.java
index 61636c3bcb..8e4893484a 100644
--- a/src/test/java/neqsim/processSimulation/processSystem/ProcessSystemRunTransientTest.java
+++ b/src/test/java/neqsim/processSimulation/processSystem/ProcessSystemRunTransientTest.java
@@ -85,6 +85,7 @@ public void testDynamicCalculation() {
     flowController.setControllerSetPoint(63.5);
     flowController.setControllerParameters(0.1, 0.10, 0.0);
 
+    p = new ProcessSystem();
     p.add(stream1);
     p.add(valve1);
     p.add(separator1);
@@ -170,6 +171,7 @@ public void testDynamicCalculation2() {
     separatorPressureController.setControllerSetPoint(7.0);
     separatorPressureController.setControllerParameters(0.5, 10.0, 0.0);
 
+    p = new ProcessSystem();
     p.add(stream1);
     p.add(valve1);
 
@@ -214,4 +216,51 @@ public void testDynamicCalculation2() {
       }
     }
   }
+
+  @Test
+  public void testDynamicCalculation3() {
+    neqsim.thermo.system.SystemInterface testSystem2 =
+        new neqsim.thermo.system.SystemSrkEos((273.15 + 25.0), 100.00);
+    testSystem2.addComponent("methane", 1.1);
+    testSystem2.addComponent("n-heptane", 1.1);
+    testSystem2.setMixingRule(2);
+
+
+    Stream feedStreeam = new Stream("Purge Stream", testSystem2);
+
+    Separator separator1 = new Separator("separator_1");
+    separator1.addStream(feedStreeam);
+    separator1.setCalculateSteadyState(false);
+    separator1.setInternalDiameter(1.0);
+    separator1.setSeparatorLength(3.0);
+
+    ThrottlingValve gasValve = new ThrottlingValve("valve_gas", separator1.getGasOutStream());
+    gasValve.setOutletPressure(7.0);
+    gasValve.setPercentValveOpening(50);
+
+    ThrottlingValve liquidValve = new ThrottlingValve("valve_gas", separator1.getLiquidOutStream());
+    liquidValve.setOutletPressure(7.0);
+    liquidValve.setPercentValveOpening(50);
+
+    p = new ProcessSystem();
+    p.add(feedStreeam);
+    p.add(separator1);
+    p.add(gasValve);
+    p.add(liquidValve);
+
+    p.run();
+
+    feedStreeam.setFlowRate(1e-10, "kg/sec");
+    liquidValve.setPercentValveOpening(1e-10);
+    System.out.println("pressure " + separator1.getPressure());
+    p.runTransient(0.01);
+    System.out.println("pressure " + separator1.getPressure());
+    p.runTransient(0.01);
+    System.out.println("pressure " + separator1.getPressure());
+    p.runTransient(0.01);
+    System.out.println("pressure " + separator1.getPressure());
+    p.runTransient(0.01);
+    System.out.println("pressure " + separator1.getPressure());
+
+  }
 }