diff --git a/src/main/java/neqsim/thermo/mixingrule/EosMixingRuleType.java b/src/main/java/neqsim/thermo/mixingrule/EosMixingRuleType.java
new file mode 100644
index 000000000..2dca6514e
--- /dev/null
+++ b/src/main/java/neqsim/thermo/mixingrule/EosMixingRuleType.java
@@ -0,0 +1,84 @@
+package neqsim.thermo.mixingrule;
+
+import neqsim.util.exception.InvalidInputException;
+
+/**
+ * Types of EosMixingRule, relating to different kind of mixing rules relevant for EOS type phases.
+ * Available types are:
+ * <ul>
+ * <li>NO - 1 - classic mixing rule with all kij set to zero</li>
+ * <li>CLASSIC - 2 - classic mixing rule with kij from NeqSim database</li>
+ * <li>HV - 4 - Huron Vidal mixing rule with parameters from NeqSim database</li>
+ * <li>WS - 5 -</li>
+ * <li>CPA_MIX - 7 - classic mixing rule with kij of CPA from NeqSim Database</li>
+ * <li>CLASSIC_T - 8 - classic mixing rule with temperature dependent kij</li>
+ * <li>CLASSIC_T_CPA - 9 - classic mixing rule with temperature dependent kij of CPA from NeqSim
+ * database</li>
+ * <li>CLASSIC_TX_CPA - 10 - classic mixing rule with temperature and composition dependent kij of
+ * CPA from NeqSim database</li>
+ * </ul>
+ *
+ * @author ASMF
+ */
+public enum EosMixingRuleType {
+  NO(1), CLASSIC(2), HV(4), WS(5), CPA_MIX(7), CLASSIC_T(8), CLASSIC_T_CPA(9), CLASSIC_TX_CPA(10);
+
+  /** Holder for old style integer pt. */
+  private final int value;
+  /** Holder for old style string physical property description. */
+
+  // We know we'll never mutate this, so we can keep
+  // a local copy for fast lookup in forName
+  private static final EosMixingRuleType[] copyOfValues = values();
+
+  /**
+   * Constructor for EosMixingRuleType enum.
+   *
+   * @param value Numeric value index for mixing rule
+   */
+  private EosMixingRuleType(int value) {
+    this.value = value;
+  }
+
+  /**
+   * Getter for property value.
+   *
+   * @return Numeric index of phase type
+   */
+  @Deprecated
+  public int getValue() {
+    return this.value;
+  }
+
+  /**
+   * Get EosMixingRuleType by name.
+   *
+   * @param name Name to get EosMixingRuleType for.
+   * @return EosMixingRuleType object
+   */
+  public static EosMixingRuleType byName(String name) {
+    for (EosMixingRuleType mr : copyOfValues) {
+      if (mr.name().equals(name.toUpperCase())) {
+        return mr;
+      }
+    }
+    throw new RuntimeException(
+        new InvalidInputException("EosMixingRuleType", "byName", "name", "is not valid."));
+  }
+
+  /**
+   * Get EosMixingRuleTypes by value.
+   *
+   * @param value Value to get EosMixingRuleTypes for.
+   * @return EosMixingRuleTypes object
+   */
+  public static EosMixingRuleType byValue(int value) {
+    for (EosMixingRuleType mr : copyOfValues) {
+      if (mr.getValue() == (value)) {
+        return mr;
+      }
+    }
+    throw new RuntimeException(
+        new InvalidInputException("EosMixingRuleType", "byValue", "value", "is not valid."));
+  }
+}
diff --git a/src/main/java/neqsim/thermo/system/SystemInterface.java b/src/main/java/neqsim/thermo/system/SystemInterface.java
index 68e73e8c0..a5a728e08 100644
--- a/src/main/java/neqsim/thermo/system/SystemInterface.java
+++ b/src/main/java/neqsim/thermo/system/SystemInterface.java
@@ -7,6 +7,7 @@
 import neqsim.thermo.ThermodynamicConstantsInterface;
 import neqsim.thermo.characterization.WaxModelInterface;
 import neqsim.thermo.component.ComponentInterface;
+import neqsim.thermo.mixingrule.EosMixingRuleType;
 import neqsim.thermo.phase.PhaseInterface;
 import neqsim.thermo.phase.PhaseType;
 import neqsim.util.ExcludeFromJacocoGeneratedReport;
@@ -1596,7 +1597,7 @@ public default int getPhaseNumberOfPhase(String phaseTypeName) {
   public double getZ();
 
   /**
-   * method to return Z volume corrected gas compressibility
+   * method to return Z volume corrected gas compressibility.
    *
    * @return double Z volume corrected
    */
@@ -2258,6 +2259,16 @@ public void setImplementedTemperatureDeriativesofFugacity(
    */
   public void setMaxNumberOfPhases(int maxNumberOfPhases);
 
+
+  /**
+   * method to set mixing rule used for the fluid.
+   *
+   * @param mr EosMixingRuleTypes enum
+   */
+  public default void setMixingRule(EosMixingRuleType mr) {
+    setMixingRule(mr.getValue());
+  }
+
   /**
    * method to set mixing rule used for the fluid.
    *
@@ -2616,7 +2627,7 @@ public default void setPhysicalPropertyModel(int type) {
   /**
    * <p>
    * setForceSinglePhase - force the fluid to be single phase of type as spesified by phasetype
-   * input
+   * input.
    * </p>
    *
    * @param phasetype a {@link neqsim.thermo.phase.PhaseType} object
diff --git a/src/main/java/neqsim/thermo/system/SystemThermo.java b/src/main/java/neqsim/thermo/system/SystemThermo.java
index a4384c7e8..44b49dde6 100644
--- a/src/main/java/neqsim/thermo/system/SystemThermo.java
+++ b/src/main/java/neqsim/thermo/system/SystemThermo.java
@@ -4434,21 +4434,23 @@ public final void setMixingRule(int type) {
   @Override
   public void setMixingRule(String typename) {
     int var = 0;
-    if (typename.equals("no")) {
+    if (typename.equalsIgnoreCase("no")) {
       var = 1;
-    } else if (typename.equals("classic")) {
+    } else if (typename.equalsIgnoreCase("classic")) {
       var = 2;
-    } else if (typename.equals("HV")) {
+    } else if (typename.equalsIgnoreCase("HV")) {
       var = 4;
-    } else if (typename.equals("WS")) {
+    } else if (typename.equalsIgnoreCase("WS")) {
       var = 5;
-    } else if (typename.equals("CPA-Mix")) {
+    } else if (typename.equalsIgnoreCase("CPA-Mix") || typename.equalsIgnoreCase("CPA_Mix")) {
       var = 7;
-    } else if (typename.equals("classic-T")) {
+    } else if (typename.equalsIgnoreCase("classic-T") || typename.equalsIgnoreCase("classic_T")) {
       var = 8;
-    } else if (typename.equals("classic-T-cpa")) {
+    } else if (typename.equalsIgnoreCase("classic-T-cpa")
+        || typename.equalsIgnoreCase("classic_t_cpa")) {
       var = 9;
-    } else if (typename.equals("classic-Tx-cpa")) {
+    } else if (typename.equalsIgnoreCase("classic-Tx-cpa")
+        || typename.equalsIgnoreCase("classic_tx_cpa")) {
       var = 10;
     } else {
       var = 1;
diff --git a/src/test/java/neqsim/thermo/system/SystemThermoTest.java b/src/test/java/neqsim/thermo/system/SystemThermoTest.java
index 905fdd96e..bdc06ab4d 100644
--- a/src/test/java/neqsim/thermo/system/SystemThermoTest.java
+++ b/src/test/java/neqsim/thermo/system/SystemThermoTest.java
@@ -6,6 +6,7 @@
 import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
 import neqsim.thermo.ThermodynamicConstantsInterface;
+import neqsim.thermo.mixingrule.EosMixingRuleType;
 import neqsim.thermo.phase.PhaseType;
 import neqsim.thermodynamicoperations.ThermodynamicOperations;
 
@@ -36,8 +37,7 @@ public static void setUp() {
    */
   @Test
   public void testCp() {
-    neqsim.thermo.system.SystemPrEos testSystem =
-        new neqsim.thermo.system.SystemPrEos(273.15 + 40.0, 1.0);
+    neqsim.thermo.system.SystemPrEos testSystem = new neqsim.thermo.system.SystemPrEos(273.15 + 40.0, 1.0);
     testSystem.addComponent("methane", 10.01);
     testSystem.addTBPfraction("C20", 10.68, 0.3, 0.85);
     testSystem.setMixingRule("classic");
@@ -144,4 +144,23 @@ void TESTsetForceSinglePhase() {
 
     assertEquals(density, testSystem.getDensity("kg/m3"), 1e-4);
   }
+
+  @Test
+  void TestMixingRuleTypes() {
+    EosMixingRuleType[] mrNum = EosMixingRuleType.values();
+    for (EosMixingRuleType mixingRule : mrNum) {
+      testSystem.setMixingRule(mixingRule.getValue());
+      assertEquals(mixingRule.getValue(), testSystem.getMixingRule());
+    }
+
+    for (EosMixingRuleType mixingRule : mrNum) {
+      testSystem.setMixingRule(mixingRule);
+      assertEquals(mixingRule.getValue(), testSystem.getMixingRule());
+    }
+
+    for (EosMixingRuleType mixingRule : mrNum) {
+      testSystem.setMixingRule(mixingRule.name());
+      assertEquals(mixingRule.getValue(), testSystem.getMixingRule());
+    }
+  }
 }