diff --git a/src/main/java/neqsim/processSimulation/processEquipment/separator/Separator.java b/src/main/java/neqsim/processSimulation/processEquipment/separator/Separator.java
index a7c0ee96f8..4c60841528 100644
--- a/src/main/java/neqsim/processSimulation/processEquipment/separator/Separator.java
+++ b/src/main/java/neqsim/processSimulation/processEquipment/separator/Separator.java
@@ -312,17 +312,23 @@ public void runTransient(double dt, UUID id) {
     if (getCalculateSteadyState()) {
       run(id);
       increaseTime(dt);
+      setCalculationIdentifier(id);
       return;
     } else {
       inletStreamMixer.run(id);
       thermoSystem.init(3);
       thermoSystem.initPhysicalProperties("density");
-      gasOutStream.getThermoSystem().init(3);
-      liquidOutStream.getThermoSystem().init(3);
+      try {
+        gasOutStream.getThermoSystem().init(3);
+        liquidOutStream.getThermoSystem().init(3);
+      } catch (Exception e) {
+        logger.error(e.getMessage());
+      }
       double deltaEnergy = inletStreamMixer.getOutletStream().getThermoSystem().getEnthalpy()
           - gasOutStream.getThermoSystem().getEnthalpy()
           - liquidOutStream.getThermoSystem().getEnthalpy();
       double newEnergy = thermoSystem.getInternalEnergy() + dt * deltaEnergy;
+      thermoSystem.init(0);
       for (int i = 0; i < thermoSystem.getPhase(0).getNumberOfComponents(); i++) {
         double dncomp = 0.0;
         for (int j = 0; j < inletStreamMixer.getOutletStream().getFluid()
@@ -336,8 +342,19 @@ public void runTransient(double dt, UUID id) {
       }
       ThermodynamicOperations thermoOps = new ThermodynamicOperations(thermoSystem);
       thermoOps.VUflash(gasVolume + liquidVolume, newEnergy, "m3", "J");
-      setTempPres(thermoSystem.getTemperature(), thermoSystem.getPressure());
       thermoSystem.initPhysicalProperties("density");
+
+      if (thermoSystem.hasPhaseType("gas")) {
+        gasOutStream.getFluid().setMolarComposition(thermoSystem.getPhase(0).getMolarComposition());
+      }
+      if (thermoSystem.hasPhaseType("oil") || thermoSystem.hasPhaseType("aqueous")) {
+        if (thermoSystem.getNumberOfPhases() > 1) {
+          liquidOutStream.getFluid()
+              .setMolarComposition(thermoSystem.getPhase(1).getMolarComposition());
+        }
+      }
+      setTempPres(thermoSystem.getTemperature(), thermoSystem.getPressure());
+
       liquidLevel = 0.0;
       if (thermoSystem.hasPhaseType("oil") || thermoSystem.hasPhaseType("aqueous")) {
         double volumeLoc = 0.0;
@@ -353,18 +370,8 @@ public void runTransient(double dt, UUID id) {
           * getSeparatorLength();
       gasVolume = (1.0 - getLiquidLevel()) * 3.14 / 4.0 * getInternalDiameter()
           * getInternalDiameter() * getSeparatorLength();
+      // System.out.println("gas volume " + gasVolume + " liq volime " + liquidVolume);
       setCalculationIdentifier(id);
-
-      if (thermoSystem.hasPhaseType("gas")) {
-        gasOutStream.setPressure(thermoSystem.getPressure("bara"), "bara");
-        gasOutStream.setTemperature(thermoSystem.getTemperature("C"), "C");
-      }
-      if (thermoSystem.hasPhaseType("oil") || thermoSystem.hasPhaseType("aqueous")) {
-        liquidOutStream.setPressure(thermoSystem.getPressure("bara"), "bara");
-        liquidOutStream.setTemperature(thermoSystem.getTemperature("C"), "C");
-      }
-      gasOutStream.run();
-      liquidOutStream.run();
       return;
     }
   }
diff --git a/src/main/java/neqsim/processSimulation/processEquipment/valve/ThrottlingValve.java b/src/main/java/neqsim/processSimulation/processEquipment/valve/ThrottlingValve.java
index 6fd0fae3bc..2e2374edee 100644
--- a/src/main/java/neqsim/processSimulation/processEquipment/valve/ThrottlingValve.java
+++ b/src/main/java/neqsim/processSimulation/processEquipment/valve/ThrottlingValve.java
@@ -1,6 +1,8 @@
 package neqsim.processSimulation.processEquipment.valve;
 
 import java.util.UUID;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import neqsim.processSimulation.mechanicalDesign.valve.ValveMechanicalDesign;
 import neqsim.processSimulation.processEquipment.TwoPortEquipment;
 import neqsim.processSimulation.processEquipment.stream.StreamInterface;
@@ -17,7 +19,7 @@
  */
 public class ThrottlingValve extends TwoPortEquipment implements ValveInterface {
   private static final long serialVersionUID = 1000;
-
+  static Logger logger = LogManager.getLogger(ThrottlingValve.class);
   SystemInterface thermoSystem;
 
   private boolean valveCvSet = false;
@@ -274,7 +276,7 @@ public void runTransient(double dt, UUID id) {
     double enthalpy = thermoSystem.getEnthalpy();
     thermoSystem.setPressure(getOutletStream().getThermoSystem().getPressure());
     // System.out.println("enthalpy inn.." + enthalpy);
-    if (isIsoThermal()) {
+    if (isIsoThermal() || thermoSystem.getTotalNumberOfMoles() < 0.0001) {
       thermoOps.TPflash();
     } else {
       thermoOps.PHflash(enthalpy, 0);
@@ -294,14 +296,19 @@ public void runTransient(double dt, UUID id) {
     // molarFlow=inletStream.getThermoSystem().getTotalNumberOfMoles();
     // }
 
-    inStream.getThermoSystem().setTotalNumberOfMoles(molarFlow);
-    inStream.getThermoSystem().init(1);
-    inStream.run(id);
-
-    outStream.getThermoSystem().setTotalNumberOfMoles(molarFlow);
-    outStream.getThermoSystem().init(1);
-    outStream.run(id);
-
+    if (molarFlow > 1e-4) {
+      try {
+        inStream.getThermoSystem().setTotalNumberOfMoles(molarFlow);
+        inStream.getThermoSystem().init(1);
+        inStream.run(id);
+
+        outStream.getThermoSystem().setTotalNumberOfMoles(molarFlow);
+        outStream.getThermoSystem().init(1);
+        outStream.run(id);
+      } catch (Exception e) {
+        logger.error(e.getMessage());
+      }
+    }
     // System.out.println("delta p valve " +
     // (inletStream.getThermoSystem().getPressure() -
     // outStream.getThermoSystem().getPressure()));
diff --git a/src/test/java/neqsim/processSimulation/processSystem/ProcessSystemRunTransientTest.java b/src/test/java/neqsim/processSimulation/processSystem/ProcessSystemRunTransientTest.java
index 304bd0557b..4d04363088 100644
--- a/src/test/java/neqsim/processSimulation/processSystem/ProcessSystemRunTransientTest.java
+++ b/src/test/java/neqsim/processSimulation/processSystem/ProcessSystemRunTransientTest.java
@@ -61,6 +61,9 @@ public void testDynamicCalculation() {
 
     Separator separator1 = new Separator("sep 1");
     separator1.addStream(valve1.getOutletStream());
+    separator1.setInternalDiameter(1.0);
+    separator1.setSeparatorLength(2.5);
+    separator1.setLiquidLevel(0.5);
 
     ThrottlingValve valve2 = new ThrottlingValve("valve_2", separator1.getLiquidOutStream());
     valve2.setOutletPressure(1.0);
@@ -79,7 +82,7 @@ public void testDynamicCalculation() {
     flowController.setTransmitter(flowTransmitter);
     flowController.setReverseActing(true);
     flowController.setControllerSetPoint(63.5);
-    flowController.setControllerParameters(1.2, 100.0, 0.0);
+    flowController.setControllerParameters(0.4, 10.0, 0.0);
 
     p.add(stream1);
     p.add(valve1);
@@ -120,7 +123,7 @@ public void testDynamicCalculation2() {
     testSystem3.setMixingRule(2);
 
     Stream stream1 = new Stream("Stream1", testSystem2);
-    stream1.setFlowRate(1000.0, "kg/hr");
+    stream1.setFlowRate(100.0, "kg/hr");
     stream1.setPressure(10.0, "bara");
     stream1.setTemperature(25.0, "C");
 
@@ -149,7 +152,7 @@ public void testDynamicCalculation2() {
 
     ThrottlingValve valve2 = new ThrottlingValve("valve_2", separator1.getLiquidOutStream());
     valve2.setOutletPressure(1.0);
-    valve2.setPercentValveOpening(50);
+    valve2.setPercentValveOpening(25);
     valve2.setCalculateSteadyState(false);
 
     ThrottlingValve valve3 = new ThrottlingValve("valve_3", separator1.getGasOutStream());
@@ -166,7 +169,7 @@ public void testDynamicCalculation2() {
     separatorLevelController.setReverseActing(false);
     separatorLevelController.setTransmitter(separatorLevelTransmitter);
     separatorLevelController.setControllerSetPoint(0.45);
-    separatorLevelController.setControllerParameters(0.0510, 200.0, 0.0);
+    separatorLevelController.setControllerParameters(1.0, 0.0, 0.0);
 
     PressureTransmitter separatorPressureTransmitter =
         new PressureTransmitter(separator1.getGasOutStream());
@@ -178,7 +181,7 @@ public void testDynamicCalculation2() {
     separatorPressureController.setTransmitter(separatorPressureTransmitter);
     separatorPressureController.setReverseActing(false);
     separatorPressureController.setControllerSetPoint(7.0);
-    separatorPressureController.setControllerParameters(0.05, 0.0, 0.0);
+    separatorPressureController.setControllerParameters(0.1, 50.0, 0.0);
 
     p.add(stream1);
     p.add(streamPurge);
@@ -202,7 +205,7 @@ public void testDynamicCalculation2() {
 
     // p.displayResult();
     p.setTimeStep(1.0);
-    for (int i = 0; i < 900; i++) {
+    for (int i = 0; i < 100; i++) {
       System.out.println("pressure " + separator1.getGasOutStream().getPressure() + " flow "
           + separator1.getGasOutStream().getFlowRate("kg/hr") + " sepr height "
           + separatorLevelTransmitter.getMeasuredValue() + "valve2 opening "