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STEP 2- ANALYSIS AND EVALUATION OF RENOVATING THE EXISTING CHILLER General There are several options for renovating or replacing the existing shell and tube rype chiller. The options include: • Re-tube the existing chiller. • Replace the existing chiller and surge ds�um wit1� satne type. • Replace the existing chiller, surge clru�n and high pressure receiver with plate and frame rype chiller system — See Step 5. The advantage of a shell and tube type chiller system is that it is naorc forgiving and easier to operate than a plate and frame rype system. There are fewer parts to maintain in a shell and tube type system and there are no gaskets to replace like in a plate and frame type system. The main disadvantage of this rype of systein is the large refrigerant charge that is required to operate the systcm, approximately twice that of a plate and frame system. Condition of the Vessel Ultra sound thickness tests were conducted on the vessel's shcf� to determine if the corrosion had affected the shell's integriry. Four locations were selected for the Apri127, 2005 tests. The chiller is divided into four sections by the tube supports. One test was taken on each side of the middle tube support in case calcium chloride was trapped on either side in concentrated levels. The remaining two tests were taken approximately 100" on each side oft�le vessel's centerjust on the outside of the end tube supports. Again, this being a logical place for concentrated levels of calcium chloride to be trapped if they exist in the section of'ii�= chiller. All tests were taken on the bottom side of the vessel. The results o�Ethe testing showed that the thickness of the vessel has not been affected by corrosion. The original wall thickness was specified at 0.4375 inches. American Engineering Testing states that a mir�i�nusn deterioration of lll6" indicates possible corrosion problems. Specification for Chiller Minimum thickness (l ll6") Test 1& 2: 6' back from flange on each end Test 2: 20" south of center Test 3: 100" south of center Test 4: 20" north of center Test 5: 100" north ofcenter 0.4375 inch 0.3750 0.4075 0.4680 0.4590 0.4450 0.4400 End bells (heads) on the chiller were also tested Test 1: North End 0.5040 Test 2: North End 0.5130 Test 3: South End 0.4190 Test 4: South End 0.4540 Test 5: South End 0.4220 The condition of the steel tubes inside the chiller has been well documented recently and therefore discussions on their condition are not included in this report.