General Information:
There are blaues und rotes Netz for the electrical supply in the industry. The voltage will be reduced through the item. The voltage loss through the cable is negligible.
- The blue one has 5 sections. 3 for cables and 1 for zero and the other for earthing. These three cables have a voltage of 240 and current of 16 A: 240*16=11kW
- The red one has 5 sections. 3 for cables and 1 for zero and the other for earthing. These three cables have a voltage of 240 and current of 32 A. The power would be 32*24*3=22kW
Every plant has two electrical nets, blue and red one. In case of the failure of one nets, the other one will be used.
Mach Number:
Mach number is a measure of compressibility of fluids. Why do we relate compressibility with the speed of sound? Because sound achieves maximum speed when fluid becomes compressible. Thus, the speed of sound becomes a good indicator of the compressibility of fluids
Electron excitation:
The process by which a molecule is excited from a low-lying electronic state to a higher energy electronic state; this can occur by absorption of a photon, by the action of an electric discharge, or as a result of a chemical reaction.
Electrostatic charge:
All atoms are made up of atoms consisting electrons, protons and neutrons. Normally, protons and electrons balance out in an atom. Hence, most objects are neutral. But, electrons are tiny. Rubbing or friction can lose electron bounds, which causes a spark by touching a positively-charged object.
Load cell (Wägezelle): It converts a force such as tension, compression, pressure, or torque into an electrical signal that can be measured and standardized. As the force applied to the load cell increases, the electrical signal changes proportionally. The most common types of load cell used are strain gauges, pneumatic, and hydraulic.
- Pneumatic load cell: elastic diaphragm which is attached to a platform surface where the weight will be balanced. The pressure gauge will transfer the air pressure to the electrical signal.
- Hydraulic load cell: It is like pneumatic one. Instead of air, fluid like oil will be used.
- Strain gauge: the most popular one
- Capacitance load cell: the capacitance of a capacitor changes as the load presses the two plates of a capacitor closer together. The current between two plates is proportional to the weight.
Brauchwasser(industrial water) ist frisches Wasser unter der Erde, was aber keine Trinkwasserqualität hat. Wenn der Erdschieber geschlossen wird, wird das Netz abgesperrt.
A joint venture (JV) is a business entity created by two or more parties, generally characterized by shared ownership, shared returns and risks, and shared governance. Companies typically pursue joint ventures for one of four reasons: to access a new market, particularly emerging markets; to gain scale efficiencies by combining assets and operations; to share risk for major investments or projects; or to access skills and capabilitie
Standard deviation: is a measure of the amount of variation or dispersion of a set of values. SD=((data-mean of data)2/number of data)(0.5)
Superficial velocity: in engineering of multiphase flows and flows in porous media, is a hypothetical (artificial) flow velocity calculated as if the given phase or fluid were the only one flowing or present in a given cross sectional area.
The residence time (RT) in minutes is the time it takes to entirely exchange the volume of the reactor and is expressed as shown above, where V = the volume of the reactor and Q is the flow rate of the effluent leaving the system.
It is like a car in autobahn, which has a velocity driving along a 12-meter street. Based on the velocity, the residence time can be calculated.
The residence time distribution (RTD): If molecules or elements of a fluid are taking different routes through the volume of a continuous operated reactor, they will spend different times within such a reactor. The distribution of these holding times is called the residence time distribution (RTD) of the fluid.
It is like cars in an autobahn. If they all have the same velocity, the residence of time of each car would be the same. Otherwise, the residence time distribution would be different.
The minimum fluidization velocity (Umf), defined as the superficial gas velocity at which the drag force of the upward moving gas becomes equal to the weight of the particles in the bed, is one of the most important parameters associated with a fluidized bed system.
Schüttdichte (bulk density)= volume fraction of air * density of air + volume fraction of particle * dichte of solid
The bulk density will be lower than the “true” density of the material, since the bulk density averages in void spaces
Laval nozzle (Lavaldüse): used to accelerate a compressible fluid ti supersonic speeds.
The Melt Flow Index (MFI) is a measure of the ease of flow of the melt of a thermoplastic polymer.
Dew point is the temperature to which air must be cooled to become saturated with water vapor. Increasing the barometric pressure increases the dew point. This means that, if the pressure increases, the mass of water vapor per volume unit of air must be reduced in order to maintain the same dew point.
Humidity is defined as the amount of water vapor (gaseous phase of water) in the air. The maximum water vapor can hold by air is affected by temperature; the higher the temperature, the greater the amount of water vapor it can hold before reach saturation.
Surface tension: a phenomenon in which the surface of a liquid, where the liquid is in contact with a gas, acts as a thin elastic sheet.
γ=0,7 N/m for water at 20C
Weep Hole Calculation: through a calculation of pressure by surface tension force ( surface tension * 2*PI*R) divided by (PI*R2)/Water drop with radius of R (50 mikrometer)
Sedimentation velocity:
Pressure: 10 bar = 1 MPa
Heat capacity: is a measure of the ability of substance to absorb heat
- Heat capacity of gas:
The specific heat capacity of ideal gases is a measure of the energy storage capacity of a molecule
Isobaric heat capacity only depends on the temperature and increases monotonically with it. It consists of two parts: a temperature-dependent, which describes the kinetic energy of the molecules and their rotational energy, and a vibration component that is only excited at higher temperatures and accounts for the temperature dependence of the size [4, 5].
When a “molecule” consists of only one atom (He, Ne, Ar, Kr, and the other noble gases), both the vibrational and rotational parts are absent, and the isobaric specific heat capacity is a constant.
Acceptable results can also be obtained using the simpler equation achieve, although the ability to extrapolate to low temperatures is weak.
The specific isobaric heat capacity of ideal gases can be estimated using Joback’s group contribution method.
Real gas corrections: With increasing pressure, intermolecular forces also play a role in the calculation of the specific enthalpy of gases.
The enthalpy difference between the state of the ideal gas at p = 0 and a state in the gas phase at any pressure can be determined for non-associating substances for a given temperature using the cubic state equations.
- Heat capacity of liquid:
Pure components:
The specific heat capacity of the liquid is a function of the temperature, the dependency on the pressure can usually be neglected.
To estimate Cp-liquid, the Rowlinson-Bondi method can be used, which is based on the spec. heat capacity of the ideal gas and the extended correspondence principle:
Mixtures:
For mixtures, the specific heat capacity of liquids can be calculated linearly, neglecting the influence of the excess enthalpy:
Some examples:
For liquid: T higher- Cp lower/ Cp water is very high due to hydrogen bonds
For gas: T higher- Cp higher
For monoatomic (Ar,…): 3/2 KB J/mol.K
For diatomic (N2,H2, O2,…): 5/2 KB J/mol.K
For polyatomic: 4 KB J/mol.K
Boltzman constant (KB): 1,38*10(-23) J/K. molecule,
1 mol= 6,023*10(+23) molecule/mol
PV=NKBT/PV=nRT: R=8,314 J/mol.K
Cp H2: 14 J/gr.K
Cp Water: 4.2 kJ/kg.K
Cp Steam: 2 kJ/kg.K
Cp ice: 2.1 kJ/kg.K
Cp propylene is like oil= 2 kJ/kg.K
Thermal Conductivity:
Kinetic theory of gas: P=2/3 (N/V)(1/2mV2): T higher: K higher
P is proportional to the number of molecules per unit volume (N/V)or to the average transitional kinetic energy
Molecular Weight:
I. Count how many atoms of each element
II. Find the relative atomic mass of each element : (mass of each isotope * the abundance)
1 amu (atomic mass unit)= 1/12 (mass of carbon)
MW of propane (C3H8): 44 kg/kmol
MW of ethylene (C2H2): 28 kg/kmol
MW of hexane (C6H14): 86 kg/kmol
Free Radical: unpaired/unstable, looking for an electron
Density:
The density is used to compare the heaviness of different components. For the gases, the MW can be used instead of density, since 1 mole gas has a volume of 22.4 lit.
Gas: At moderate pressures of up to about 5 bar, the ideal gas law can be used to calculate the density of the gas phase of non-associating substances:
P=(density)RT (steam at STP, 0 and 1 bar: 0,5 kg/m3/ air: 1 kg/m3 H2: 0,08 kg/m3)
To calculate the density of gases non-associating substances at higher pressures are suitable for cubic state equations such as those of Peng-Robinson (PR): In order to determine molar volumes of gases using the PR or SRK equation, the critical data and the acentric factor are required.
Liquid: Thermodynamic tables, only dependent on the temperature, The PPDS equation is currently considered to be the best correlation:
Density of a mixture (liquid and solid) : sum of mass fraction of each component*density of component
Liquid and solids have very small changes in volume with changes T or P. They can be considered as incompressible. The exception is to have solid dissolved in the liquid.
Normdichte:
That is the density at 0C and 101,32 Kpa, in which on mole gas has a volume of 22.4 lit.
Kg/h= Nm3/h * Normdichte (it does not depend on the temperature and pressure, since the calculation is based on the mole mass
kg/h at a T1 and P1 can be calculated based on the Normdichte and m3/h at T1 and P1: Density 1: P1/(Z1RT1) Density (STP): PN/(ZNRNTN)
Viscosity:
Viscosity is highly dependent on temperature.
Dynamic viscosity of gas increases by increasing the temperature due to more molecular interactions and more collisions. The viscosity of gas is caused by inter-molecular collision. According to the kinetic theory of gases, the viscosity of an ideal gas is independent of the density. This can be explained by the fact that at low gas densities, on the one hand, fewer particles are available for momentum exchange, but, on the other hand, more momentum can be transferred per collision due to the longer mean free path. Both effects cancel each other out in the ideal gas; in the real gas, on the other hand, the viscosity increases with the density. On the other hand, there is a pronounced dependency on the temperature, because the average kinetic energy of the particles increases with increasing temperature and thus more momentum can be transferred.
Dynamic viscosity of liquid reduces by increasing the temperature. Above the melting point, it falls steeply with temperature. The viscosity of liquid is caused by inter-molecular cohesive forces. One of the simplest ways of estimating the dynamic viscosity of liquids is the group contribution method according to Orrick/Erbar. The viscosity can then be calculated using
For T > 0,7 Tc, Sastri recommends:
With increasing pressure, the viscosity of the liquid increases
on. According to Lucas , the effect can be estimated via
Water: 1 centipoise at 20C and 0.5 at 50C
Viscosity causes pressure drop along the pipe. Without viscosity, there would be no shear stress.
Flow of high viscosity fluids is more likely laminar because any small turbulent disturbances are easily damped by larger shear stresses.
Dynamic Viscosity of Liquid:
Mole percent:
Mole percent of gas is equal to volume percent as long as temp. and pressure are constant (PV=nRT)
Mole percent of liquid can be calculated using molecular weight and density
Critical point:
Critical temperature, critical pressure and critical volume can be estimated quite well using group contribution methods. The method according to Joback is recommended.
Structure group contributions:
Air: -140 C/40 bar
Water: 373C/220 bar
For a pure substance, the critical pressure is defined as the pressure above which liquid and gas cannot coexist at any temperature. The critical temperature for a pure substance is the temperature above which the gas cannot become liquid, regardless of the applied pressure.
Critical point: the point in temperature and pressure on a phase diagram where the liquid and gaseous phases of a substance merge together into a single phase.
Vapor phase: refers to a gas phase at a temp. where the same substance can also exit in the liquid or solid below the critical temp.
Viscosity:
Dynamic: 1 posie: 0.1 Pa.S (Water :1 mPa.s/ Honey: 20 Pa.s)
Kinetic: 1 St: 10(-4) m2/s
Density:
Oil: 950 kg/m3 at 15C (Change of density with temperature: 6.1 * 10^(-4)/K)
Iron: 7870 kg/m3
Silver: 10000 kg/m3
Gold: 20000 kg/m3
Propylene: 500 kg/m3
Wax. 870 kg/m3
Melting point of wax: 70–120 C
Boiling temperature of propylene at 1 bar: -47C /at 25 bar: 60 C
Stock Point:
a liquid turns into a solid
10% ethanol causes -10C for a freezing point
Flash Point:
Benzin < 20C
Normal Condition: 0C and 101,325 KPa
Standard Condition: 0C and 100 KPa, One mole of gas at S.T.P. has a volume of 22,4 liter
The difference between Nm3/h and m3/h:
If you have m3/h, you can calculate the Nm3/h as follows:
- Density at T and P
- Density at normal conditions
m3/h * (Density at T and P)/(Density at normal conditions)
- T and P
m3/h *(P/normal pressure)*(normal temperature/T)*(Real gas factor at T and P/Real gas factor at normal condition)
If you have kg/h, Nm3/h will be calculated as the following:
kg/h*kmol/kg*22,4lit/mol
Softening point vs melting point:
The melting point is the temperature where all the crystallinity in the bags and film is destroyed. When this happens, the bag will completely disperse into the rubber. The softening point describes a temperature where the bag will begin to experience noticeable changes in physical properties.
Melting Point and Enthalpy of Melting:
Its estimation is a complex task since the melting point is determined by the enthalpy of melting, which is influenced by intermolecular interactions, and by the entropy of melting, which is a function of the molecular symmetry.
Polyethylene softens when heated (at 80–120°C)
Units:
1 ft=30 cm
I in=0,03 m
100 m * 100 m=1 Hektar
10 m * 10 m=1 Da
1 Ib = 0,45 kg
1 Ibf=4.4 N
Sound velocity of water: 1450 m/s
Superheated Steam
It can be achieved by only increasing the temperature. If the pressure is reduced, it will be still the saturated steam in some regions.(see hs diagram)
Vapor pressure of pure components can be calculated through using Clausius-Clapeyron Equation/Antoin/Wagner, whereas Reid vapor pressure (RVP)is a common measure of the volatility of gasoline and other petroleum product.
With increasing the tempearture, the vapor pressure and the liquid enthalpy increases, while the vaporation enthalpy and steam enthalpy reduces. By incrasing the temperature, steam and liquid would be more similar together until the critical point. Hence, the latent heat would be smaller. At the critical point, vapor and liquid become identical and the enthalpy of vaporization becomes 0.
Vapor Pressure:
- Pure Substance:
The Antoine equation derived from the Clausius–Clapeyron relation is notorious for its poor extrapolation ability. The Antoine equation cannot reproduce the value range from the triple point to the critical point with sufficient accuracy.
A low-pressure parameter set is used to describe the vapour pressure curve up to the normal boiling point and the second set of parameters is used for the range from the normal boiling point to the critical point.
The Wagner equation can describe the entire range from the triple point to the critical point and should be used in sufficient quantity to fit good data precisely. A weakness of the equation is extrapolation to low temperatures.
- Mixtures
The estimation of vapor pressures for mixtures does not make sense from a physical point of view, since the concentrations of vapor and liquid differ when a mixture boils. The boiling point and dew point of a mixture with a specified concentration are not identical.
Azeotropic mixtures are often treated as a pure substance; but even this only makes sense within a certain temperature range.
Evaporation enthalpy:
- Pure Components:
The estimation of the vaporization enthalpy has a special feature compared to the other quantities with the Clausius-Clapeyron equation:
Care must be taken to ensure that only the temperature range in which the vapor pressure curve is backed up by measured values is taken into account. However, the usual vapor pressure equations such as Wagner or Antoine extrapolate poorly to low temperatures.
As a rule of thumb, it is recommended not to use the Clausius-Clapeyron equation for vapor pressures ps < 1 mbar.
If v′′ is determined using the equation of state of the ideal gas, the error in the range of low pressures is tolerable, but the result is a curve with a concave instead of convex curvature, which becomes less and less acceptable towards higher pressures. v′′ is therefore mostly determined with cubic state equations
In the area just below the critical point, however, the inaccuracy is much greater here too. Considering that both v′′ and v′ are much less precise in the critical region and that v′ also plays a role here, so that (v′′– v′) as a difference of large numbers is particularly error-prone , the application of the Clausius-Clapeyron equation in this range must be ruled out. The rule of thumb here is that T < Tc — 30 K should be.
- Mixtures:
As an approximation, it can be stated that in the case of isothermal evaporation, which is very rare in technology, the evaporation enthalpy can simply be linearly averaged over the components:
The influences of the excess enthalpies and the expansion of the evaporated gas are neglected. In the case of isobaric evaporation, the situation is considerably more complicated. The vaporization enthalpies of the individual components must then be determined at their respective boiling point. In addition to the excess enthalpy, the temperature change of the liquid is not taken into account.
Normal Boiling Point:
In the event that no information is available, the normal boiling point (abbreviated: NBP for normal boiling point) can be calculated according to Joback can be approximately determined analogously to the estimation of the critical temperature:
Latent Heat:
Latent heat of oil: 400–500 kJ/kg
Latent heat of steam at 1 bar: 2200 kJ/kg
Types of bonds:
to share or attract electrons based on electronegativity
Nonpolar covalent bonds: share electrons between two similar atoms (electronegativity difference <0,5): H2/O2
Diatomic oxygen is made up of the same two elements, and they equally share the 4 electrons that make up the double bond between them. They’re equally electromagnetic, which means that there are not any partial charges for each element.
Polar covalent bonds: share electrons between two different atoms (electronegativity difference >0,5): H2O
Ionic bonds: share electrons between two different atoms with enough electronegativity difference : NaCl
Hydrogen bonds: hold different hydrogens together, H with N, O and F,
- makes water cohesive
- water has two permanent dipoles (separation of charges/ electron density is shared unequally between atoms)
Van der Waals bonds:
- briefly attracted
- shouldn’t have two permanent dipoles
Valence electrons:
The number of valence electrons that it may have depends on the electron configuration in a simple way. For example, the electronic configuration of phosphorus (P) is 1s2 2s2 2p6 3s2 3p3 so that there are 5 valence electrons (3s2 3p3)
Propane
- a melting point -187C
- a boiling point -42C
- using as a cold medium (95% Propane and 5% Butane is cheaper than 100%propane)
- Van-der-Waals bonds
Hydrogen to Helium Fusion:
- Fusion: two or more coming together or merging one single entity
- Nuclear: process which includes nucleus
- Energy of Sun due to reducing proton, E=MC2, C:300000000 m/s
Gas analysis:
- Several components:
Chromatography: is used for the separation of a mixture, which is dissolved in a fluid (gas or solvent): mobile phase (Trägergas) carries the sample through a system ( a column, capillary tube,…), on which a material called stationary phase. The different stay time (different distribution coefficients, Fick’s Law) results in different velocities in mobile phase. The chromatograh will be calibrated once a year.
For getting the sample from the plant, there is alway a recyle stream from high pressure to the low pressure. Sample from the plant: magentic valve (on/off): rotameter(to see whether the flow is there): bypass (to get a fresh sample): nozzle valve (+ mobile phase (Nitrogen + Hydrogen) und Air for the instruments and flushing): capillary pipe: separation column: detector. At the end, the sample will be sent to the flare system.
Concentration:
we use 4 samples with different volumes to get the calibration diagram. The calibration diagram will be drawn by the volume and area of the peak. Then, we can get y=ax+b (y: volume, x: area of the peak). Then, we can inject the sample and read the peak. Then, we may find the volume of our sample.
For the curves, the time is important. According to the calibration curve and the time of unknown sample, the concentration can be determined.
Retention time:
Boiling point : If a component has a low boiling point, then it is likely to spend more time in the gas phase. Therefore its retention time will be lower than a compound with a higher boiling point. A compound’s boiling point can be related to its polarity.
Column temperature: A high column temperature will give shorter retention times, as more components stay in the gas phase but this can result in poor separation. For better separation, the components have to interact with the stationary phase.
Carrier gas flow-rate: A high flow rate lowers retention times but also yields a poor separation.
Column length: A longer column will produce longer retention times but better separation. Unfortunately, if a component has too long a transit time in the column, there can be a diffusive effect that causes the peak width to broaden.
2. Single component
