efficiency of 1,1-dichloroethane for various processes

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CHEG231 Chemical Engineering Thermodynamics I Semester Project Ciaran Bowen, Sean Daniels, Tyler Walters, Dipan Vaidya

1,1-dichloroethane December 11, 2015



Abstract

Power generation and refrigeration are two concepts of thermodynamics thatalways have room for improvement in efficiency and cost effectiveness. In this report welook at the compound 1,1-dichloroethane to analyze its suitability for the aboveprocesses as an alternative to other possible compounds. To do so our team will use a

combination of both real data and our own calculated values, in collaboration withMATLAB and Mathematica codes to turn the information into visible plots and graphs.Upon interpreting the data from our plots, graphs, and calculations, we were able todetermine that, compared to steam, 1,1-dichloroethane has a lower power generationefficiency, 55.7% compared to 65%-90% for steam, and performs more poorly in theRankine refrigeration cycle (coefficient of performance of .169 versus 5.016 for steam).The results of this compound are not sufficient enough to make it a highly viablecompound for industrial use, due to its lack of cost effectiveness. After reviewing ourresults, we were able to conclude that 1,1-dichloroethane is far from a miraclecompound when it comes to efficiency and power generation.



Figure 1. Structure of 1,1Dichloroethane

Introduction 1,1-dichloroethane is a colorless, oily organic compound consisting of two

chlorines attached to the first carbon in an ethane chain1. 1,1-dichloroethane has anormal boiling point of 330.5 ± 0.5 K and a normal melting point of 176.7 K. The criticalpoint at 50.61 bar occurs at a temperature of 523.4 K. 1,1-dichloroethane is present in all

three states at once at a temperature of 176.18 K 2. 1,1-dichloroethane evaporateseasily at room temperature and burns even more easily. However, this compound doesnot appear in the environment naturally1.

1,1-dichloroethane is created mainly through the reaction of hydrogen chlorideand vinyl chloride (a major component of PVC polymers) at temperatures rangingbetween 20-55˚C in the presence of aluminum, ferric, or zinc chloride3. Other, lessfrequent production methods include the direct chlorination of ethane, addition ofhydrogen to chloride to acetylene, the reaction of ethylene and chlorine in the presenceof calcium chloride, and the reaction of phosphorouschloride and acetaldehyde. 1,1-dichloroethane is also abyproduct during the creation of chloral, vinyl chloride viaethylene oxychlorination, and as an intermediate in the

production of 1,1,1-trichloroethane through thermal orphotochemical chlorination of vinyl chloride. It is also anunwanted byproduct in the oxychlorination processes of C2hydrocarbons4. There is no reported data in the SRIDirectory of Chemical Producers for the production volumeof 1,1-dichloroethane, however national production volume isestimated to be in the range of 1,000,000 to 10,000,000pounds per year. Three companies are reported to haveproduced 1,1-dichloroethane in the United States of America: Dow Chemical Company,Shin Etsu Company, and Oxy Vinyls. Dow Chemical Company reported 0 pounds peryear for imported data, exported data, manufactured data, and volume used on site asthey claim it to be confidential business information. The substance is, however,

reported to be used as an intermediate, a substance used to form another compound.Shin Etsu also has withheld imported data and manufactured data, however they export1,844,512 pounds per year. They use a volume of 2,629,704 pounds per year on sitecurrently and an estimated 2,959,696 pounds per year on site in past production4.

Besides being an intermediate for other chemical processes, mainly the creationof 1,1,1-trichloroethane, 1,1-dichloroethane can also be used as a solvent for plastics,oils, and fats, and therefore can be used as a cleaning agent and a degreaser. 1,1-dichloroethane used to be used as an anesthetic. Today, 1,1-dichloroethane is usedcommercially in fabric spreading, varnish and finish removers, organic synthesis, oreflotation, and fumigant and insecticide spray, and is a component in the creation ofplastic wrap, adhesives, and synthetic fiber

4.

" ToxGuide for 1,1-dichloroethane. ATSDR, http://www.atsdr.cdc.gov/toxguides/toxguide-133.pdf (accessed Dec 2015).

# Ethane, 1,1-dichloro-. Ethane, 1,1-dichloro-. NIST,

http://webbook.nist.gov/cgi/cbook.cgi?id=c75343&units=si&mask=4 (accessed Dec 2015). $ PRODUCTION, IMPORT/EXPORT, USE, AND DISPOSAL . ATSDR,

http://www.atsdr.cdc.gov/toxprofiles/tp133-c5.pdf (accessed Dec 2015). % ToxProfile for 1,1-dichloroethane. ATSDR,

http://www.atsdr.cdc.gov/toxprofiles/tp133-c5.pdf (accessed Dec 2015).



1,1-dichloroethane breaks down rather slowly in air and therefore has the abilityto withstand long-range transport4. This substance also does not dissolve easily in waterbut it can evaporate from the water into the air. Unless soil has a high organic content,this substance will not bind strongly to it. The 1,1-dichloroethane that does bind to soilcan evaporate into the air or move into groundwater. Because of its frequency in the air,water, and certain types of soil, one can be exposed to 1,1-dichloroethane by breathing

in air from industrial releases or hazardous waste sites, drinking contaminated water, ortouching contaminated soil. Only a very small concentration will enter the body,however, due to 1,1-dichloroethane’s high volatility4.

Even though the ways in which humans can come into contact with 1,1-dichloroethane are conceivable, not much information on humans and the effectsassociated with environmental exposure are available. The substance used to be usedas an anesthetic, but it was found that high concentrations of the substance causeanesthesia and irregular heartbeats. Even though it has not been tested, the EPArecognizes 1,1-dichloroethane as a possible carcinogen. For an 8-hour workday, OSHAhas set a legal limit of 100 ppm of 1,1-dichloroethane4.

In terms of cost, 1,1-dichloroethane is relatively cheap. All elements in the

compound (hydrogen, chlorine, carbon) have a high earth abundance. In production,

extra hydrochloric acid is added to vinyl chloride, already one of the top twenty largest

petrochemicals in production, in presence of inexpensive catalysts such as aluminum

chloride5. Furthermore, the reaction can be performed at room temperature, attributing to

the production costs being fairly low.

5 Vinyl Chloride Monomer (VCM). Chemical Economics Handbook (CEH),

https://www.ihs.com/products/vinyl-chloride-monomer-chemical-economics-handbook.html (accessedDec 2015).



Methodology

The equation of state used for analysis is a modified version of the Peng-Robinson equation. The reason for using this equation of state is that the (modified)Peng-Robinson equation, which incorporates a new attractive coefficient for polarmolecules, takes into account polarity of organic molecules, unlike the original Peng-

Robinson equation of state and other equations of state. 1,1-dichloroethane has twochlorine molecules on one carbon molecule and therefore is an unsymmetrical molecule. An unsymmetrical molecule is polar.

The modified Peng-Robinson equation of state is as follows:6

where

Table 1. The key parameters and critical properties used in the above E.O.S., the Antoine equation, and other useful parameters 7 Tc Critical temperature 523.4 K* Pc Critical pressure 50.61 bar* Ttrip Triple point temperature 176.18 K** V Molar Volume Assumed: 1.000 L/mol for

sake of P-T diagram ac constant 17.1097374 L2/mol2 b constant 0.0668946212 L/mol m constant .85748

n constant -0.71522 ! constant 0.48536 A (T range: 212.5- 330.6K) Antoine coefficient 4.22153 B (T range: 212.5- 330.6K) Antoine coefficient 1229.158 C (T range: 212.5- 330.6K) Antoine coefficient -39.204 Tboil Normal boiling point 330.5K** Tmelt Normal melting point 176.7K** !subH sublimation enthalpy 38.87 kJ/mol*** !fusH fusion enthalpy 7.870 kJ/mol @ 176.18K** *No real data for critical volume was found **No real data for pressure or volume was found ***No real data for pressure or temperature was found

& Aznar, M.; Telles, A. A DATA BANK OF PARAMETERS FOR THE ATTRACTIVE COEFFICIENT OF THE

PENG-ROBINSON EQUATION OF STATE. Scientific Electronic Library Online,http://www.scielo.br/scielo.php?pid=s0104-66321997000100003&script=sci_arttext (accessed Dec 2015).

' Ethane, 1,1-dichloro-. Ethane, 1,1-dichloro-. NIST,

http://webbook.nist.gov/cgi/cbook.cgi?id=c75343&units=si&mask=4 (accessed Dec 2015).



In order to retrieve the pressure- temperature diagram, constants were pluggedinto the equation of state and then a volume of 1.000 L/mol was assumed. After that, theequation was coded into MATLAB twice- once for a temperature range for the solid-vapor line (0.00K to triple point) and once again for the liquid vapor line (triple point tocritical point). From there, a rough estimate was used for the solid liquid line, as it isknown that a roughly vertical, linear, positive- sloping line represents that region for

mostly all compounds except for water. For charts of density vs. pressure for different isotherms, constants were defined

in Wolfram Mathematica and the equation of state was coded so pressures could easilybe changed. The equation was solved for different volumes at a constant temperatureover a range of pressures. The real values were input into a table in Excel in which theywere converted to density values of g/cm3 and graphed vs. respective pressures in bar.This process was repeated for each isotherm. In a similar fashion, to plot density vs.temperature for different isobars, the same code as above was used and the equationwas solved for volumes at a constant pressure over a range of temperatures. Thesevalues were converted to density, graphed vs. respective temperatures, and repeated foreach isobar.

To find the power generation and efficiency of 1,1-dichloroethane in an adiabatic

turbine, mass, energy, and entropy balances were used. The departure functions forenthalpy and entropy were used. The power generation of the turbine is equivalent toshaft work, or the mass flow times the change in enthalpy. For enthalpy, the departurefunction is the sum of the difference between each enthalpy at a temperature andpressure with its ideal gas state, and the difference in ideal gas enthalpies for the twostates. The difference in ideal gas enthalpies for the two states is the integral of the Cp*term, the molar heat capacities of gases in the ideal gas state, from one temperature tothe other. For the efficiency, the change in entropy is needed, found using the entropydeparture function, similar to the enthalpy departure function. The efficiency is thechange in enthalpy over the change in enthalpy minus change in entropy. Given the conditions provided in the problem statement, saturated temperatures of theliquid and vapor phases were solved. From there, using the steps of the Rankine

refrigeration cycle, temperature and pressure at each point in the cycle were filled in.Using an adapted version of the Peng Robinson equation of state solver from thetextbook CD, enthalpy, entropy, and volume at each point in the cycle were calculated8.From there, the points were graphed on Excel and coefficient of performance was solvedusing the formula for COP.

( Sandler, S. Chemical Engineering Thermodynamics; Fourth.; John Wiley & Sons: US, 2015.



Results

Figure 2. Pressure-Temperature phase diagram using modified Peng RobinsonEquation of State. Refer to Table 1 and preceding equations for key parameters used to

reach this solution. See Appendix A1 for relevant MATLAB code.



Figure 3-1. Graph of Density versus Pressure for 1,1-dichloroethane at five differenttemperatures including room temperature, the boiling and melting temperatures, and atemperature slightly below the critical temperature.

Figure 3-2. Screenshot of excel workbook with values of pressure, molar volume, andcalculated densities (from left to right respectively) for 1,1-dichloroethane at five differenttemperatures. See Appendix B1 for Mathematica code used to calculate molar volumeand density values.



Figure 4-1. Graph of Density versus Temperature for 1,1-dichloroethane at five differentpressures including atmospheric pressure and the critical pressure.

Figure 4-2. Screenshot of excel workbook with values of temperature, molar volume,and calculated densities (from left to right respectively) for 1,1-dichloroethane at fivedifferent pressures. See Appendix B2 for Mathematica code used to calculate molarvolume and density values.



Figure 5-1. (top left) Mass,energy, and entropy balancesfor problem 5. Equation of Statewith coefficients. Figure 5-2. (above) Usingenthalpy departure function tosolve for power generation ofthe turbine for problem 5. Figure 5-3. (left) Using anentropy departure function tosolve for efficiency for problem

5.



Figure 6-1. Methodology usedfor solving Coefficient ofPerformance for 1,1Dichloroethane in the Rankine

Refrigeration Cycle.

Figure 6-3. Data used for the Cycles

Figure 6-2. Plot of Temperature vs. Entropy for 1,1 Dichloroethane in aRankine Refrigeration Cycle

Figure 6-4. Plot of Pressure vs. Specific Volume for 1,1Dichloroethane in a Rankine Refrigeration Cycle



Using 1,1-dichloroethane as a means of power generation, although feasible isnot very economical. A common industrial steam turbine’s efficiency ranges from 65 to90 percent, whereas 1,1-dichloroethane is about 55.7 percent10. Steam is both moreefficient and more abundant, making it a more desirable option for power generation.

Similar to power generation, 1,1-dichloroethane can be used as a refrigerant, butit is very inefficient with a coefficient of performance of about 0.169. Water at similar

conditions has a C.O.P. of about 5.016 when solved in a similar fashion to the 1,1-dichloroethane. So, although feasible to use as a refrigerant, it is not advisable becauseof its economical disadvantage. The Figures 6-2 and 6-4 demonstrate the cycle’s pointswith respect to Temperature vs. Molar Entropy and Pressure vs. Molar Volume,respectively for 1,1-dichloroethane. In these graphs, it can be observed that two stepsrepresent isentropic compression and expansion, and the other two steps representisobaric (and isothermal in one case) evaporation and condensation.

"* Turbine Info. All About Turbines, http://www.turbinesinfo.com/steam-turbine-efficiency/ (accessed Dec 2015).



Conclusion

Overall, 1,1-dichloroethane has a bleak outlook on its implementations in powerand refrigeration cycles, matching its current limited industrial and commercial uses. Asof today, the only semi-popular industrial use for 1,1-dichloroethane as just an

intermediate to create 1,1,1-trichloroethane, a more widely used compound. Its highvolatility makes it useless for most other applications. In transportation, problems ariseas temperature must be lowered and pressure must be raised to keep it in liquid formbecause 1,1-dichloroethane evaporates easily.

In the Rankine power generation cycle, the compound came out to be 55.7%efficient. Most steam turbines are anywhere from 65-90% efficiency in this same cycle.In the refrigeration cycle, the coefficient of performance was calculated as .169, while forsteam under the same ideal conditions was calculated to have a COP of 5.016.Therefore, 1,1-dichloroethane simply cannot compete with a cheap, readily available,industrially practical and thermodynamically useful compound like water in any aspect.



References

1,1-Dichloroethane. Toxic Substances Portal, http://www.atsdr.cdc.gov/toxfaqs/tf.asp?id=717&tid=129 (accessed Nov 2015).

Aznar, M.; Telles, A. A DATA BANK OF PARAMETERS FOR THE ATTRACTIVE COEFFICIENT OF THE PENG-ROBINSON EQUATION OF STATE. ScientificElectronic Library Online, http://www.scielo.br/scielo.php?pid=s0104-66321997000100003&script=sci_arttext (accessed Dec 2015).

Ethane, 1,1-dichloro-. Ethane, 1,1-dichloro-. NIST, http://webbook.nist.gov/cgi/cbook.cgi?id=c75343&units=si&mask=4 (accessedDec 2015).

Kumagai, A.; Takahashi, S. (Pressure, volume, temperature) behaviour of liquid 1,1-dichloroethane and 1,2-dichloroethane. (Pressure, volume, temperature)behaviour of liquid 1,1-dichloroethane and 1,2-dichloroethane,http://www.sciencedirect.com/science/article/pii/0021961485900114 (accessed Dec2015).

PRODUCTION, IMPORT/EXPORT, USE, AND DISPOSAL . ATSDR,http://www.atsdr.cdc.gov/toxprofiles/tp133-c5.pdf (accessed Dec 2015).

ToxGuide for 1,1-dichloroethane. ATSDR, http://www.atsdr.cdc.gov/toxguides/toxguide-133.pdf (accessed Dec 2015).

ToxProfile for 1,1-dichloroethane. ATSDR, http://www.atsdr.cdc.gov/toxprofiles/tp133-c5.pdf (accessed Dec 2015).

Turbine Info. All About Turbines, http://www.turbinesinfo.com/steam-turbine-efficiency/ (accessed Dec 2015).

Sandler, S. Chemical Engineering Thermodynamics; Fourth.; John Wiley & Sons: US, 2015.

Shanbhag, S. Cpdata.m. Cpdata.m, https://people.sc.fsu.edu/~sshanbhag/thermo/cpdata.m (accessed Dec 2015).

Urieli, I. Exergy - Adiabatic Control Volumes. Exergy - Section b) Adiabatic Control Volumes (updated 3/22/12),

https://www.ohio.edu/mechanical/thermo/applied/chapt.7_11/chapter7b.html(accessed Dec 2015).

Vinyl Chloride Monomer (VCM). Chemical Economics Handbook (CEH), https://www.ihs.com/products/vinyl-chloride-monomer-chemical-economics-handbook.html (accessed Dec 2015).



Acknowledgments Dipan wrote part of the introduction, methodology, results, and discussion and generatedthe P-T phase diagram Ciaran wrote part of the introduction, results, and generated results for power generationand refrigeration coefficient of performance, as well as the graphs for the exact path ofthe cycle on specific volume-pressure and specific entropy-temperature graphs.

Tyler wrote part of the methodology, results, discussion, and conclusion and helpedgenerate the density plots Sean wrote part of the methodology, results, discussion, and conclusion and helpedgenerate the density plots and the P/V and T/S graphs and values.

All members contributed to the data analysis, appendices, and resources

Ciaran Bowen x______________________________________________

Sean Daniels x______________________________________________

Dipan Vaidya x______________________________________________

Tyler Walters x______________________________________________



Appendix

A- Matlab Codes

A1- Pressure Temperature Phase Diagram Code



A2 - Matlab code for departure function enthalpy and entropy changes calculated

in Problem 5.



B- Mathematica Codes

B1 - Mathematica code for finding molar volume as a function of pressure and

temperature for five different temperatures. The code is shown for a temperatureof 425 K and a pressure of 20 bar.

Conversion from the molar volume to density in grams per cubic centimeter

Density = (1/V)*(98.92/1000)



B2- Mathematica code for finding molar volume as a function of pressure and

temperature for five different pressures, and the code for converting the molarvolume to density in grams per cubic centimeter. Shown for a temperature of 450

K and a pressure of 20 bar.

Conversion from the molar volume to density in grams per cubic centimeter

Density = (1/V)*(98.92/1000)

efficiency of 1,1-dichloroethane for various processes

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