Heat Transfer Within A Jacketed Reactor System

Heat Transfer Within A Jacketed Reactor System Modeling of heat transfer within a jacketed reactor requires basic knowledge on process heat transfer; reactor design etc. literature review sum up the fundamental on energy balance, method of overall heat transfer coefficient determination and basic understanding of crystallization. These are the basic methods which allow engineers to predict more accurate capabilities during chemical process as well as timing on the process. Introduction Heat transfer is important in agitated vessels due to fluid temperature is the most significant factor for controlling the outcome of chemical, biochemical and pharmaceutical processes. [6] Jacketed agitated vessels for heating and cooling are commonly used in vary types of process applications. Engineers should have working knowledge of how heat transfer and temperature control principles applied to such vessels. Cooling or heating agitated liquid in vessels is a basic technological operation on the chemical, biochemical, pharmaceutical, food and processing industries. The cooling or heating rate depends on how the heat is supplied or removed, the mixing intensity and many other parameters. [5] The temperature needs to be controlled precisely at its desired to meet the requirement of downstream operations. Hence a mathematical model is essential which can predict temperatures accurately. The rate of heat transfer to or from an agitated liquid mass in a vessel is a function of the physical properties of that liquid and of the heating or cooling medium, the vessel geometry, and the degree of agitation. [8] Other factors which may affect the rate of heat transfer include type and size of the agitator and agitator location in the vessel. Most of the jacketed agitated vessels are used as reactor, thus chemical reactions with exothermic or endothermic effects must be taken into account as well. In a vessel containing an agitated liquid, heat transfer takes place mainly through conduction and forced convection, as it does in heat exchangers. [8] Crystallization is a unit operation for separation and production of pure solid materials with desired properties. To develop a batch cooling crystallization process, various operation strategies need to be investigated in relation to seeding, cooling, mixing, fines dissolution, and so forth. [18] In commercial scale process, the reactor size grows larger. In this situation, various problems like ancillary nucleation, attrition, breakage, agglomeration, and dead zone may become severer in relation to the increasing inhomogeneities in the solution temperature and hydrodynamics. Literature Review Modeling of reactors is useful for analyzing data, estimating performance, reactor scale-up, simulating start-up and shut down behavior, and control. [12] Uncertainties such as scale-up options, explosion hazards, runaway reactions, environmental emissions, reactor internals etc, may be explored through modeling. [12] A key aspect of modeling is to derive the appropriate momentum, mass or energy conservation equations for the reactor. One typical application in heat transfer with batch operation is heating the process fluid in reactor, maintaining temperature during the reaction period and cooling the product after reaction complete. [11] Energy Balance The overall thermal energy balance includes the heat entering the system, heat leaving the system, heat accumulation and heat loss. The equation can be written as: In batch process, there is no liquid or fluid entering or leaving the system. If the system is assumed to be perfectly insulated, the energy balance equation can be simplified in: [7] By integration of both sides: For a batch manufacturing process, heat transfer in an agitated vessel is used to design a suitable process or reaction. It is necessary to calculate the time to heat or cool a batch or the cooling capacity required to hold an exothermic or endothermic reaction at constant temperature. [1] The technique is to develop an expression which is relating time for heating or cooling agitated batches to coil or jacket area, heat-transfer coefficient, and the heat capacity of the vessel contents. [11] By rearranging the energy balancing equation, the relevant equation to calculate time is as follow: This equation only can be used in where the utility fluid temperature remains constant or the fluid temperature difference between inlet and outlet is not greater than 10% of the log mean temperature difference between the average temperature of the jacket and the temperature of the vessels content. [8] Precisely, for heating and cooling condition, this equation must be represented in separately: For heating: For cooling If the situation is greater than 10% of the log mean temperature difference, the apply equation will be: W = the mass flow rate through the jacket, C = the specific heat of the fluid in the jacket K = Assumptions are made for solving energy balance equation [11] [17] U is constant for the process and over the entire surface Liquid flow rates are constant Specific heats are constant for the process The heating or cooling medium has a constant inlet temperature Agitation produces a uniform batch fluid temperature No partial phase changes occurs Heat losses are negligible Agitated vessel heat transfer coefficient Process side heat transfer coefficient can be determined by speed and agitator type. For low viscosity fluids, high-speed turbine type agitators will provide good performance. For high viscosity fluids and non-newtonian fluids, larger diameter agitators will be more suitable. [1] Various types of agitators are used for mixing and blending as well as to promote heat transfer in vessels. The correlations used to estimate the heat transfer coefficient to the vessel wall. [2] For agitated vessels: Where hv = heat transfer coefficient to vessel wall or coil, Wm-2à ¢Ã¢â‚¬Å¾Ã†â€™-1 D = agitator diameter, m N = agitator, speed, rps (revolutions per second) Ï  = liquid density, kg/m3 kf = liquid thermal conductivity, Wm-1à ¢Ã¢â‚¬Å¾Ã†â€™-1 Cp = liquid specific heat capacity, J Kg-1à ¢Ã¢â‚¬Å¾Ã†â€™-1 ÃŽ ¼ = liquid viscosity, Nm-2s. The values of constant C and the indices a, b and c depend on the type of agitator the use of baffles, and whether the transfer is to the vessel wall or to coils. Some typical correlations are given below: [2] Flat blade disc turbine, baffled or unbaffled vessel, transfer to vessel wall, Re < 400: Flat blade disc turbine, baffled vessel, transfer to vessel wall, Re> 400: Overall heat transfer coefficient Most utility and process fluid will foul the heat transfer surfaces in an exchanger to a greater or lesser extent. The deposited material will normally have a relatively low thermal conductivity and will reduce the overall coefficient. Fouling factors usually are considered in determining the Overall heat transfer coefficient U. The overall heat transfer coefficient is calculated in this way: Where ÃŽ ± and ÃŽ ±s are the heat transfer coefficients for the process and utility side respectively. On the utility side, fouling resistance 1/ÃŽ ±f can be found from local experience or from Kern (1950). [1] Heat transfer utility fluid Syltherm 800 is a silicone heat transfer fluid. It is a highly stable, long-lasting silicone fluid designed for high temperature liquid phase operation. It exhibits low potential for fouling and can often remain in service for 10 years or more. The recommended using temperature range is. [15] Crystallization Crystallization occurs with generating a sufficient level of supersaturation. The method of generation of supersaturation is to provide heat transfer, which is used in cooling and evaporative crystallization processes. There are two essential steps for crystallization: nucleation and crystal growth. The problems of scale-up in crystallization process can be classified into induced, hydrodynamically induced, and mixes. For example, attrition, breakage, and agglomeration are related to solution mixing and are investigated from the hydrodynamic point of view. On the other hand, ancillary nucleation is caused by increased temperature gradient within the solution together with seed particles generated by attrition or fluid shear and can be considered as an example where the thermal and hydrodynamic effects are mixed. To improve the hydrodynamics deterioration during the scale-up, impeller type, agitation power, and baffle or draft tube design2,8,9 can be modified or newly designed as required. The thermal aspect improvement is performed by the heat transfer enhancement, but the remedies are limited because the heat transfer area to volume ratio decreases inevitably during the scale-up unless other techniques such as vacuum or evaporative crystallization is introduced. Methodology Calculation of time to heat or cool a fixed amount of liquid inside a batch reactor usually assume the process and utility heat capacity and the overall heat transfer coefficient to be constant throughout the calculations. Equations (liquid in jacket) heat input to reactor at T = heat loss by utility liquid with inlet temperature T1 and outlet temperature T2 Rearrange the equation to solve unknown jacket outlet temperature T2 The rate of temperature change of the liquid inside the vessel is given by Solving the above two equations to get process temperature as a function of time Finally, solving for time t where T = Tf Conclusion

Commerce Study Notes Year 9

Commerce Law and Society Laws: * A rule that governs the way you live, with minimal standards. * Protects people and keeps peace. * Have freedoms, resolve disputes, protection. Anarchy: Without order. Mediation: a third person that ultimately decides, outside of court * * Registered person. * Two parties and mediator. * A compromise is made. * Mediations cheaper and voluntary. Matrimonial: property of marriage, everything is shared * * Matrimonial assets. * Court considers contributions of parties. * Child is child of marriage Government in Australia Governments make laws to control us. They set up systems to enforce laws. * Governments set up courts to decide upon breaches of laws. Jury decides whether the person is guilty or not, the judge decides the punishment Democracy: Demo=People, Cracy=State * People elected by the people under a free voting system. All have equal rights. * Provides laws and order, controls economic problems, and protects people / environment. Types of Govern ments * Communism: No private ownership. Government owns everything and provides the needs/ wants of the people. E. G. China, North Korea. Monarchy: The Monarch (king, queen, emperor, empress, sultan) E. G. Kuwait, Saudi Arabia. * Constitutional Monarchy: Powers of the monarch reduced by laws. Governor General represents the Monarch. E. G. Australia operates as a democracy. * Anarchy: Government has broken down. No laws or authority. * Socialism: Ownership of all production (farms and factories) controlled by the people. Government puts responsibility on people. E. G. Sweden * Federation: Involves Federal, State and local governments. Federal Government Issues * Customs * Currency * Defence Immigration/ emigration. * Aboriginal affairs. * Foreign affairs * Social security (makes people feel more secure) * Marriage/ divorce. The Australian Federal government is based on a bicameral system. * * Upper house – Senate76 people * Lower house – house of Reps 150 people State Government * * Each state divided into electorates * 93 electorates in NSW for lower house (legislative assembly- green room). * 43 electorates for upper house. * Voters elect a representative. * Each electorate contains 40,000 to 50,000 people.Jurisdiction * Each state in USA and Aus have legal jurisdiction. (authority in law) * Unity and centrality- POWER * Freedom of speech, same rights (equality), justice. 3 Areas of Power Legislation – parliamentary law – voting politician Executive – carries out law – police Judiciary – courts and judges – statue and case law Judiciary 1st level: Local Court (judge and magistrate) minor matters e. g. shop lifting 2nd District Court (judge)fairly serious matters e. g. armed robbery 3rd level: Supreme Court (Judge/ justices) serious criminal matters e. g. ife in-jailment 4th High Court (Judge) looks at paperwork, no evidence Federal Courts – deal with federal law * Federal magistrates court of Aus tralia * Federal court of Australia e. g. Family Courts Facts * Australian constitution sets out Federal powers. * Federal law prevails over state law. * Trade practices act: Federal * Bankruptcy Hierarchy of Courts in Australia – state courts * High court of Australia (up to 7 judges) * Federal court * Supreme court of appeal * Supreme court * District court * Local court Court Administration 1. Registry: Handles the paperwork of the court.Charges fees. 2. Registrar: Boss of the registry. What impact do fees have on justice? Fees restrict people’s access to the courts causing injustice and can be seen as discrimination. It also reduces the demand on the court system. It also deters frivolous or silly cases. Contracts * A contract is a legally enforceable agreement between parties, outlining the obligations. * Oral/ verbal contract: mouth (spoken). * Signed contract: written (signed by parties). * Most contracts are oral but are signed when involving large sums of mone y. Elements of a contract . Offer: A proposal where the person making an offer must clearly communicate. 2. Acceptance: Occurs when the person making an offer agrees to the proposal. 3. Consideration: Required to form a valid contract. Requires each party to give up something of value. * Implied term: nothing in writing but a code of conduct is established. Cases * PS of Great Britain v BBC Ltd (1953): Customers offer can be refused. (the check out accepts offers) * C v CSB Co. (1893): Misleading advertising can be a contract. (offer at large) * Chappel & Co. V Nestle Co.Ltd (1960): Even with no value something can be passed from one party to another forming a contract. (caveat emptor – buyer beware) The difference between Private law and Public law Private law (civil): laws that regulate people’s behaviour with other individuals. (non-criminal matters e. g. suing for civil wrongs) Public law (criminal): People’s behaviour within society. (criminal law, protects people from other people – e. g. robbery, homicide , drug offences) Courts * Juries are normally involved in serious matters. * For minor matters you only have a local court magistrate.The adversail system: two sides go against each other in an argument or a fight to argue their case. List the main courtroom officials * The judge (your worship) * The judge assistant * The lawyers * The transcript reporter * The jury (6-12 in criminal case) * The barrister * The magistrate (your honour) Robbery: taking property that belongs to someone else using threats/ violence. Civil law Civil law deals with no criminal matters. It allows an individual to sue other people Negligence Trespassing Defamation Nuisance Where a civil law is successfully proven in court, the wronged party will seek damages.The award of legal costs normally goes to the successful party that is either the plaintiff or defendant (but can be refused as these costs are discretionary – up to judge) Civil Law Tes t To prove their test they must win â€Å"the balance of probability† more likely/ no certainty of truth. Criminal Law Test â€Å"Beyond a reasonable doubt† approx. Equal to certainty (protects people from others who do the wrong thing). â€Å"Ignorance of the law is no excuse†. In criminal law you have a Prosecutor: In local courts usually police whereas in the higher courts prosecute is known as the Crown prosecutor. the Crown (R= Regina which means loyalty) v.Defendant In criminal matters the injured party is the State or the Crown. The offence is not against the person that has suffered at the hands of the alleged perpetrator but rather against the State (Crown). In criminal matters the victim cannot decide to punish the offender. This is for the Crown to make. Courtroom acts and definitions Indictable offences: Serious crimes that are determined or tried by a judge or jury. Summary offences: Less serious crimes which are relatively quickly dealt with by a m agistrate in a local court. Manresa: To have a guilty mind. If you are insane you cannot have mensrea.Quasi: Semi criminal. In between civil and criminal. Injunction: Order of the court to stop doing something. E. g. Stop playing loud music. Contempt of Court: Disregarding or breathing an injunction or court order. Statute Law: Law made by parliament. Restitution: paying for damage caused by contempt of court Case/ common law: Law made by judges. How laws are made Statute Law: made by parliament through the passing of a bill or a referendum. Common/ case law: Law is made by the courts of previous cases. 2 houses of parliament (legislative) 1st Lower house (house of reps) 2nd Upper house (senate)If a bill is continuously rejected than a double dissolution can be called meaning the public go to the polls to re-elect senators and representatives in the lower house. A courts primary role is to interpret and apply the laws of the parliament. Common law: A judge can alter common law as it has arisen through the judges in England and then Australia. Alters law when necessary to allow justice. What binds the Common Law Precedent in law means those principles that have been decided in the past that a court can rely on today. Higher courts make a precedent. How a bill becomes law The cabinet draft bills with senior ministers. cabinet is the prime minister) Bill is given to each member of parliament, then it gets read out loud for debate and voted in House of Reps. If majority in favour bill is passed to senate. If passed in senate it goes to executive (governor general) for Royal assent (Is now an ACT of Parliament). If senate rejects bill they send it back as is or with amendments. If rejected for a second time a double dissolution can be called. Common law Develops over time case by case. Each case represents a precedent. Precedent A strong example, defies what has happened before through principles of law. Judges RoleInterpret statute, common law, delegated legislati on (ministerial law), and to enforce laws. Equality: Enforcement of the law should be fair and should result in equal punishments or penalties. A judge cannot lean on the scale (meant to be impartial). Our system is adversarial system (each party represented by a lawyer). Justice: All people are equal before the law. Symbols of justice The blindfold: Justice is impartial (not influenced by wealth, race, sex, ect†¦ ). The scales: Represent the legal system (weighing up both sides of argument). The sword: The punishment to be imposed on any guilty party.

Similarities Between Christianity And Islam - 1427 Words

Christianity and Islam share much common ground. They trace their origins to Abraham; believe in prophecy, apostles, revelation, scripture, resurrection, and life after death. Christianity and Islam have related theological traditions; believe in one omnipotent God who is concerned with human salvation. Both religions are somewhat similar in how they embrace their beliefs; what the church is to Christianity, the umma is to Islam. Notwithstanding these important similarities, however, these two worldviews have a number of significant differences as well. This paper will explore, compare and contrast some of the similarities and the difference of both religions. Word Count: 97 The†¦show more content†¦Muslims do not support the theory that human beings advanced from apes, but that that the life of human beings began with the creation of Adam and Hawwa (Eve) and that God did not create them from dust and breathe life into Adam to become the first man but that he reached where he is now after transitioning through many stages. The Qur’an revealed that man’s first stage was a condition of non-existence. Prior to the creation of the universe, there was a stage period when nothing existed. (Qur’an, Surah19) Another stage in the creation process was a state of existence when the human body was created but the brain or its active abilities were not yet developed. Man was a human body, which was not yet a human being. There was the physical human body minus the evolved and perfected human brain or mind. He was in the form of a being without consciousness and intelligence, not aware of himself or of other things (Qur’an Surah 19). The third stage in the evolution of man was reached when he entered a state of being and began to form through the seed of the male, planted in the body of the female through sexual intercourse. The fourth stage developed the human brain to perfection and presented a highly developed form of awareness and intelligence. After completing the creation, the Qur’an states that Allah settled Himself upon the Throne to oversee His work (Quran, Surah 50:38).