P&ID and Process EvaluationMelissa Rosdiana Dewi

1.0 INTRODUCTIONTetrahydrothiophene is another word for thiophane. The molecular formula of thiophane is SCH2CH2CH2CH2 with density of 0.999g/mL at 20oC. Thiophane has flash point at 21oC and its evaporation residue is less than 0.2 weight percent. Looking at its safety data, it is clearly indicated that thiophane is a highly flammable material. Any faulty when handling this material will result in explosion with explosion rate ranging from 1.1% to 12.3%. Hence, it is very important to use suitable materials and appropriate process to avoid any unwanted events. (http://msds.chem.ox.ac.uk/TE/tetrahydrothiophene.html)

2.0 OBJECTIVESThe objective of this report is to select suitable materials for equipments used in the production of thiophane. Besides that, this report also tests the ability to convert a specified process of thiophane into a simplified block diagram. In addition, this report provides an opportunity to understand and to know more about the materials used to make the equipments in a process plant.

NoUnit OperationComponentsRequirementsSuitable MaterialJustification

1EvaporatorTetrahydrofuran

2MixerH2S & THF (vapor)

3Reactor H2S & THF with alumina catalyst, water Can withstand heat Has to be corrosion resistant as H2S is corrosive304 stainless steel Excellent corrosion and oxidation resistant Able to withstand heat Ease of cleaning and fabrication Has approximately the same characteristics with 304L stainless steel but is chosen due to its cheaper price

4Cooling TowerThiophane, unreacted H2S & THF, water

5Separator Thiophane, unreacted H2S & THF, water

6FurnaceUnreacted H2S

7Caustic Wash TowerNaOH, thiophane, THF, water

8Distillation Column NaOH, thiophane, THF

9

Storage Tank

Thiophane

- No pressure exist- Do not use container containing residue- Sealable container is preferable- Do not consist of heat - Non corrosive

Carbon steel-Carbon steel can withstand corrosion without the presence of acidic and alkaline conditions.-No heat appear here, hence carbon steel can be used. Since it is only used for storage purpose, low cost material such as carbon steel is suitable.

3.0 MATERIAL SELECTION

Thiophane Storage Tank Specification Sheet

Item : Thiophane Storage TankDate : 29/03/09

Item number : 9

Total item : 1System : Batch

Function : To storage Thiophane ready stock

Operation : Batch

Material : Carbon Steel

Composition : C = 1% ; Fe = 99 %

Pressure : -

Temperature : ???

Data Specification

Major characteristics : Carbon steel not suitable for highly acidic and alkaline compound. High pressure and temperature conditionare not recommended. Less corrosive component is preferableProperties : High availability Low cost Ease of fabrication Limited corrosion resistance (-ve)Applications : General purposes

MaterialsCharacteristics

Carbon steel High availability Low cost Ease of fabrication Limited corrosion resistance (-ve)

304 Stainless Steel Excellent forming and welding characteristics Excellent corrosion and oxidation resistance due to the chromium content Heat resistance Excellent toughness Ease of cleaning Ease of fabrication Beauty of appearance

304L stainless steel High level of corrosion resistance Resistance to oxidation Excellent toughness Prevention of product contamination Ease of fabrication Excellent formability Ease of cleaning High strength with low weight

316 stainless steel Better corrosion resistance than type 304 Oxidation resistance Non-hardenable by heat treatment Can be readily formed and drawn

Aluminum bronze High corrosion resistance Has superior machineability and is longer wearing High strength High tarnish resistance Resistance to oxidation

Aluminum Very light Ease of fabrication Resistance to acids Corrosion resistance Very sensitive to trace contamination

442 stainless steel Oxidation resistance Corrosion resistance Ideal for high-heat applications Difficult to fabricate A high-chromium, heat-resistant steel

4.0 CONCLUSION5.0 REFERENCES

http://msds.chem.ox.ac.uk/TE/tetrahydrothiophene.htmlhttp://www.inchem.org/documents/icsc/icsc/eics0677.htmhttp://www.steelmedia.com/steel-composition.htm[Curtin University of Technology] |