• Extensive research in a team of four on how to reduce CO2 emissions from a cement factory • Focused on reducing CO2 emissions from the calciner reactor by using substitute reactant materials and running a simulation on Aspen HYSYS to determine the least CO2 produced

1. Pg. 1
Project 2 Memorandum
TO: J.R.Boss, President, Chair and CEO, EPA Corp
FROM: Alfonso Figueroa, NaHCO3
DATE: 4/6/2016
SUBJECT: Substitution of Reactant Materials in Reducing CO2 Emissions
The newly proposed worldwide climate contract is put in effect where The Worried Earth
Environment Protectors LLC (WEEP LLC) is looking into reducing CO2 emissions. WEEP LLC
hired the Enforce Paris Accord Corp (EPA Corp) to reduce CO2 emissions from a processing
plant. A cement plant was chosen and one of the subsections of the cement plant to be worked on
was the Calciner reactor. The alternative materials fly ash and slag were looked into as
substitutes for pure limestone. A HYSYS model was created to determine which reagent would
most reduce CO2 emissions and minimize cost. Slag ends up being the reactant of choice due to a
reduction of 443,782 tonnes of CO2 emissions and savings of $24,126,639.58 per year.
With the agreement of The Paris Climate Conference in December 2015, companies have
started looking into how to reduce CO2 emissions [1]. The Worried Earth Environment Protectors
LLC (WEEP LLC) is already looking into reducing CO2 emissions from a processing plant. In
reducing CO2 emissions from a manufacturing plant, WEEP LLC has contracted with the Enforce
Paris Accord Corp (EPA Corp) to maximize incremental ROI from processing plants while
maintaining the present production rate. EPA Corp has decided to reduce CO2 emissions from a
concrete processing plant [2]. To reduce carbon emissions from the cement facility, different
subsections of the plant were viewed and one of the subsections of focus was the Calciner [3].
Cement is used in nearly all types of construction projects including dams, bridges,
sidewalks, and parking garages. The cement business has accounted for up to 5% of CO2

2. Pg. 2
emissions internationally due to the resultant high demand. The demand is projected to increase
from 2.55 billion tons to around 3.7 – 4.4 billion tons by 2050. With the cement industry
contributing a large amount of CO2 emissions to the atmosphere, designing a greener plant is
vital to society [4].
Before EPA Corp can start looking into alternatives for the Calciner process unit, some
safety guidelines from the American Institute of Chemical Engineers (AIChE) Code of Ethics
must first be followed. By following the AIChE Code of Ethics, EPA Corp has made sure to be
cognizant of the safety and health of the public and environment [5]. In implementing the AIChE
Code of Ethics, a HAZOP analysis is performed on the Calciner reactor [6].
Table 1: HAZOP Analysis
In order to reduce CO2 emissions, the Calciner reactor must be checked for all possible
consequences and applications of the recommended actions were applied to the reactor.
The Calciner section of the cement facility involves the decomposition of limestone
where the CaCO3 in the mineral decomposes to CO2 and CaO via a calcination reaction [3].
Since a CO2 molecule is released for every one decomposition of CaCO3, a general rule followed
is one ton of cement produced is equivalent to one ton of CO2 produced. The main focus is to
then find a way to reduce the use of CaCO3 by substituting the feed with alternative materials.

3. Pg. 3
Out of the possible alternative materials to use, slag and fly ash are ideal to be used as a
substitute because of their pozzolanic properties [7].
Fly ash is composed of necessary salts required for the kiln process which mainly include
SiO2, CaO, and trace minerals [8]. With these identical salts necessary for the kiln process, fly
ash can combine with limestone in a 50/50 weight composition. Slag is composed of mainly
CaSiO3 and a few trace minerals where the chemical is similar to the final cement product [9].
Slag is able to form an admixture with limestone in an 80/20 weight composition. To find out
which substitute can most reduce CO2 emissions, a HYSYS model is created [3][7].
Figure 1: HYSYS Model of Calciner Reactor
After generating the final CO2 emissions for each reactant as well as the price of the process, with
added carbon credit taking into account for CO2 savings, the results are as follow in table 2 [10].
Table 2: HYSYS Results
Reactant Reactant Flow Rate
(tonne/yr)
CO2 Flow Rate
(tonne/yr)
Total Flow Rate Cost
($/yr)
Milled Limestone 1,576,800 554,683 34,689,600.00
Slag/Limestone (80/20) 1,576,800 110,902 10,562,960.42
Fly Ash/Limestone (50/50) 1,576,800 277,342 35,528,522.42
In gathering the final results from HYSYS, table 2 shows the reactant slag contributed the most
reduction in CO2 and savings in money. The amount of CO2 saved per year with the choice of
slag is 443,782 tonnes and the amount of carbon credit received is $5,596,085.98. Compared to
using purely limestone, the slag mix ends up saving $24,126,639.58 per year resulting in only
needing to pay $10,562,960.42 per year.

4. Pg. 4
References
[1] “Paris Agreement,” europa. http://ec.europa.eu/clima/policies/international/negotiations/
paris/index_en.htm (accessed February 28, 2016)
[2] Beckman, James. EPA Corp. word (accessed February 21, 2016)
[3] “Overview of Process Modeling Software: Utilizing Alternative Fuels in Cement Plant
for Air Pollution Reduction,” cscanada. www.cscanada.net/index.php/est/article/down
load/j.est...356/pdf (accessed March 30, 2016)
[4] “Emissions from the Cement Industry,” columbia. http://blogs.ei.columbia.edu/2012/
05/09/emissions-from-the-cement-industry/ (accessed February 28, 2016)
[5] “Code of Ethics,” aiche. http://www.aiche.org/about/code-ethics (accessed April 3, 2016)
[6] Plant design and economics for chemical engineers. 5th ed., McGraw-Hill, New York, NY,
Print.
[7] “Low CO2 Concrete,” us-concrete. http://us-concrete.com/sustainability/ef-technology/
(accessed February 28, 2016)
[8] “Fly Ash Facts for Highway Engineers,” fhwa. http://www.fhwa.dot.gov/pavement/recy
cling/fach01.cfm (accessed April 1, 2016)
[9] “Extraction of Metals,” gcsescience. http://www.gcsescience.com/ex20.htm
(accessed April 1, 2016)
[10] “California Carbon Dashboard,” calcarbondash. http://calcarbondash.org/
(accessed April 3, 2016)
[11] “Heat of Formation Table for Common Compounds,” chemistry.about.
http://chemistry.about.com/od/thermodynamics/a/Heats-Of-Formation.htm
(accessed April 1, 2016)

5. Pg. 5
[12] “Calcium Oxide MSDS,” sciencelab. http://www.sciencelab.com/msds.php?msdsId
=9927480 (accessed April 1, 2016)
[13] “Wollastonite-1A Mineral Data,” webmineral. http://webmineral.com/data/Wollastonite-
1A.shtml#.VwTsCk8rKUk (accessed April 1, 2016)
[14] “Enthalpy of formation of wollastonite (CaSiO.) and anorthite (CaAlrSirOr) by
experimental phase equilibrium measurements and high-temperature solution
calorimetry,” minsocam. http://www.minsocam.org/ammin/am79/am79_134.pdf
(accessed April 1, 2016)
[15] “Selling Prices For Iron And Steel Slag In The United States,” indexmundi.
http://www.indexmundi.com/en/commodities/minerals/iron_and_steel_slag/iron_and_stee
l_slag_t2.html (April 2, 2016)
[16] “Fly Ash,” concreteconstruction. http://www.concreteconstruction.net/images/Fly
%20Ash_tcm45-346438.pdf (April 2, 2016)
[17] “Young’s Sand & Gravel,” youngssandandgravel. http://www.youngssandandgravel.com/
pricelist.htm (April 2, 2016)

6. Pg. 6
Appendix A: HAZOP Analysis
A detailed HAZOP analysis grid in helping to identify any hazards that can occur throughout the
calciner reactor [3][6].
Table 1: HAZOP Analysis

7. Pg. 7
Appendix B: Reactant Material Properties
Physical properties of reactant materials that are required to be inputted into HYSYS
[3][11][12][13][14].
Table 3: Reactant Material Properties
Reactant Material Molecular Weight Density
(kg/m3)
Heat of Formation
(kJ/kgmol)
CaO 56.08 3350 −6.3550 × 102
SiO2 60.06 2320 −8.4517 × 105
CaSiO3 116.16 2910 −8.9610 × 104
CaCO3 100.09 2930 −1.2113 × 106

8. Pg. 8
Appendix C: HYSYS Calculations
To create the simulation of a calciner reaction, the desired components must be added.
Since the reactant materials are solids, HYSYS does not have the relevant data stored in the data
bank. To add the solids into HYSYS, the Hypotheticals tab must be selected and then solids can
be added. When inserting new solids, the reactant material properties based off Table 3 are
applied so that the materials can be used in the simulation. Once the hypothetical solids are
created, they are added to the component list as well as CO2. The fluid package of choice to be
used in the model is the Sour SRK equation.
The next step is to view the reactions tab to create the calcination reaction for the calciner
reactor. The reaction involves the thermal decomposition of calcium carbonate into CO2 and CaO
as follows in the stoichiometric equation [3]:
𝐶𝑎𝐶𝑂3 → 𝐶𝑂2 + 𝐶𝑎𝑂
Once the equation is put into the stoichiometry tab, the basis tab is then selected. Calcium
Carbonate is selected as the base component, the reaction phase is set at overall, and the initial
concentration is set at 100%. After the reaction set is made, the fluid packages tab is selected, and
then the reactions tab is chosen, the available reaction set can then be added to the current
reaction set.
Entering into the simulation environment, the calciner reactor can be created. Three
calciner reactors are created so that each reactant material is able to produce their CO2 outlet
flows. Before specifying each reactor’s feed composition, the general design for each reactor
must be specified. Each feed stream is set at an inlet flow of 180,000 kg/hr at a temperature of
700 C°, a pressure of one atmosphere, and at a vapor phase of zero. Now the conversion reactor is
selected from the case menu where the inlet flow is attached to the unit.

9. Pg. 9
The next step is to drag out an outlet flow for CO2 emissions, an outlet flow for products,
and an inlet flow for energy. By selecting the reactor and then clicking the reactions tab, the
created reaction is applied to the reaction set. The outlet flow for CO2 emissions is set at a
temperature of 950 C°, a pressure of one atmosphere, and at a vapor phase of one. With all the
initial conditions set, the solver can then be set to active for the reactor to solve the process
model [3].
The first calciner reactor is fed 100% pure limestone which consists of a mixture of 80%
SiO2 and 20% CaCO3 via weight percent [3]. The second calciner reactor is fed an 80/20 slag and
limestone mix consisting of 16% CaCO3, 4% SiO2, and 80% CaSiO3 via weight percent [9]. The
third calciner reactor is fed a 50/50 fly ash and limestone mix consisting of 40% CaCO3, 18%
CaO, and 42% SiO2 via weight percent [8]. Having everything set up for on HYSYS, the
following data is gathered for the flow rates of each reactant’s calciner reactor[7].
Table 4: HYSYS Stream Flow Results
Reactant Reactant Flow Rate
(kg/hr)
CO2 Flow Rate
(kg/hr)
Product Flow Rate
(kg/hr)
Milled Limestone 180,000 63,320 116,700
Slag/Limestone (80/20) 180,000 12,660 167,300
Fly Ash/Limestone (50/50) 180,000 31,660 148,300
Figure 1: HYSYS Model of Calciner Reactor

10. Pg. 10
Appendix D: CO2 and Cost Reduction
A table of prices per tonne of each reactant material and for the savings of CO2 is created
as follows [10][15][16][17]:
Table 5: Price per Tonne for reactants and CO2 savings
Reactants and CO2 Savings Price ($/tonne)
CO2 12.61
Limestone 22.00
Slag 7.31
Fly Ash 27.50
Before any further calculations can be taken place, the kg/hr given by HYSYS for the feed and
CO2 flow rate are converted to tonnes/yr. A sample calculation is given for the reactant flow rate
as follows:
𝑅𝑒𝑎𝑐𝑡𝑎𝑛𝑡 𝐹𝑙𝑜𝑤 𝑅𝑎𝑡𝑒 =
180,000 𝑘𝑔
ℎ𝑟
×
1 𝑡𝑜𝑛𝑛𝑒
1000 𝑘𝑔
×
8760 ℎ𝑟𝑠
𝑦𝑟
𝑹𝒆𝒂𝒄𝒕𝒂𝒏𝒕 𝑭𝒍𝒐𝒘 𝑹𝒂𝒕𝒆 = 𝟏, 𝟓𝟕𝟔, 𝟖𝟎𝟎
𝒕𝒐𝒏𝒏𝒆
𝒚𝒓
A table is created to summarize all the reactant flow rates and CO2 emissions flow rates in units
of tonnes per year for each reactant.
Table 6: Reactant and CO2 Flow Rates for tonnes per year
Reactant Reactant Flow Rate
(tonnes/yr)
CO2 Flow Rate
(tonnes/yr)
Milled Limestone 1,576,800 554,683
Slag/Limestone (80/20) 1,576,800 110,902
Fly Ash/Limestone (50/50) 1,576,800 277,342
Having the flow rates in their proper units, the next step is to convert the tonnes per year
into dollars per year. Using the prices given in Table 5, the conversions can be completed for
each flow rate. Calculation of the slag reactant flow rate has a composition of an 80/20 admixture

11. Pg. 11
with limestone, so both prices have to be considered. The slag reactant flow rate can be solved
for as follows:
𝑆𝑙𝑎𝑔 𝑟𝑒𝑎𝑐𝑡𝑎𝑛𝑡 𝑓𝑙𝑜𝑤 𝑟𝑎𝑡𝑒 𝑝𝑟𝑖𝑐𝑒 = (20% ×
1,576,800 𝑡𝑜𝑛𝑛𝑒
𝑦𝑟
×
$22.00
1 𝑡𝑜𝑛𝑛𝑒
) +
(80% ×
1,576,800 𝑡𝑜𝑛𝑛𝑒
𝑦𝑟
×
$7.31
1 𝑡𝑜𝑛𝑛𝑒
)
𝑺𝒍𝒂𝒈 𝒓𝒆𝒂𝒄𝒕𝒂𝒏𝒕 𝒇𝒍𝒐𝒘 𝒓𝒂𝒕𝒆 𝒑𝒓𝒊𝒄𝒆 =
$ 𝟏𝟔, 𝟏𝟓𝟗, 𝟎𝟒𝟔. 𝟒𝟎
𝒚𝒓
Calculating the slag’s CO2 savings is done by taking the difference between limestone’s CO2
flow rate and slag’s CO2 flow rate. This step is done because it determines how many tonnes of
CO2 is saved per year. The next step is then to calculate how much money is gained from the
CO2 savings as follows:
𝑆𝑙𝑎𝑔 𝐶𝑂2 𝑓𝑙𝑜𝑤 𝑟𝑎𝑡𝑒 𝑝𝑟𝑖𝑐𝑒 = (
554,683 𝑡𝑜𝑛𝑛𝑒
𝑦𝑟
−
110,902 𝑡𝑜𝑛𝑛𝑒
𝑦𝑟
) ×
$12.61
1 𝑡𝑜𝑛𝑛𝑒
𝑺𝒍𝒂𝒈 𝑪𝑶 𝟐 𝒇𝒍𝒐𝒘 𝒓𝒂𝒕𝒆 𝒑𝒓𝒊𝒄𝒆 =
$ 𝟓, 𝟓𝟗𝟔, 𝟎𝟖𝟓. 𝟗𝟖
𝒚𝒓
A table is created to organize the price per year for each of the reactants as follows:
Table 7: Reactant and CO2 Flow Rates for dollars per year
Reactant Reactant Flow Rate
($/yr)
CO2 Flow Rate
($/yr)
Milled Limestone 34,689,600.00 0
Slag/Limestone (80/20) 16,159,046.40 5,596,085.98
Fly Ash/Limestone (50/50) 39,025,800.00 3,497,277.58
The milled limestone has a CO2 flow rate of zero dollars per year because no CO2 is saved in the
process.
The final step is determining which reactant reduces the most CO2 and saves the most
money per year. From Table 6, it is clear that the slag limestone mixture produces the least

12. Pg. 12
amount of CO2 in the calciner reactor. Determining the reactant that costs the least amount per
year can be calculated by taking the difference of the carbon credit received from the CO2 flow
rate and the cost of the reactant flow rate. A sample calculation is done for fly ash as follows:
𝐹𝑙𝑦 𝐴𝑠ℎ 𝑇𝑜𝑡𝑎𝑙 𝐹𝑙𝑜𝑤 𝑅𝑎𝑡𝑒 𝐶𝑜𝑠𝑡 =
$39,025,800.00
𝑦𝑟
−
$3,497,277.58
𝑦𝑟
𝑭𝒍𝒚 𝑨𝒔𝒉 𝑻𝒐𝒕𝒂𝒍 𝑭𝒍𝒐𝒘 𝑹𝒂𝒕𝒆 𝑪𝒐𝒔𝒕 =
$𝟑𝟓, 𝟓𝟐𝟖, 𝟓𝟐𝟐. 𝟒𝟐
𝒚𝒓
A table is created to sum up each reactant’s total flow rate cost.
Table 8: Price per Tonne for reactants and CO2 savings
Reactant Total Flow Rate Cost
($/yr)
Milled Limestone 34,689,600.00
Slag/Limestone (80/20) 10,562,960.42
Fly Ash/Limestone (50/50) 35,528,522.42
The reason for milled limestone’s total flow rate cost being the same as the reactant flow rate
cost is because limestone does not receive any carbon credit since no CO2 is reduced.
Based off Table 8, it is clear to see that slag ends up costing the least amount per year to
be kept in operation. Comparing the slag mixture to pure limestone, the savings is calculated as
follows:
𝑆𝑎𝑣𝑖𝑛𝑔𝑠 𝑖𝑛 𝑑𝑜𝑙𝑙𝑎𝑟𝑠 𝑝𝑒𝑟 𝑦𝑒𝑎𝑟 𝑢𝑠𝑖𝑛𝑔 𝑠𝑙𝑎𝑔 = $34,689,600.00 − $10,562,960.42
𝑺𝒂𝒗𝒊𝒏𝒈𝒔 𝒊𝒏 𝒅𝒐𝒍𝒍𝒂𝒓𝒔 𝒑𝒆𝒓 𝒚𝒆𝒂𝒓 𝒖𝒔𝒊𝒏𝒈 𝒔𝒍𝒂𝒈 = $𝟐𝟒, 𝟏𝟐𝟔, 𝟔𝟑𝟗. 𝟓𝟖
The slag mixture also reduces the most CO2 emissions as follows:
𝐶𝑂2 𝑟𝑒𝑑𝑢𝑐𝑡𝑖𝑜𝑛 𝑖𝑛 𝑡𝑜𝑛𝑛𝑒𝑠 𝑝𝑒𝑟 𝑦𝑒𝑎𝑟 𝑢𝑠𝑖𝑛𝑔 𝑠𝑙𝑎𝑔 𝑚𝑖𝑥 =
554,683 𝑡𝑜𝑛𝑛𝑒
𝑦𝑟
−
110,902 𝑡𝑜𝑛𝑛𝑒
𝑦𝑟
𝑪𝑶 𝟐 𝒓𝒆𝒅𝒖𝒄𝒕𝒊𝒐𝒏 𝒊𝒏 𝒕𝒐𝒏𝒏𝒆𝒔 𝒑𝒆𝒓 𝒚𝒆𝒂𝒓 𝒖𝒔𝒊𝒏𝒈 𝒔𝒍𝒂𝒈 𝒎𝒊𝒙 =
𝟒𝟒𝟑, 𝟕𝟖𝟐 𝒕𝒐𝒏𝒏𝒆
𝒚𝒓
Based offthe two calculations, the slag mix is the reactant ofchoice in reducing CO2 emissions.