Sunday 30 June 2013

NDMA pegs death toll at 10,000, NORTH INDIA TSUNAMI

Dehradun/New Delhi: The National Disaster Management Authority on Sunday said that the death toll in Uttarakhand floods might cross 10,000. "Like the Speaker said, it could be more than 10,000. The exact number, however, cannot be known immediately," NDMA Vice Chairman Shashidhar Reddy said. He added that as many 1500 people are still stranded in the hill state.
Uttarakhand Assembly Speaker Govind Singh Kunjwal had said on Saturday that he fears that more than 10,000 people could have been killed in the calamity. "When I returned from Garhwal, I said the death toll could be between 5000 and 10,000. But now I think the death toll could be more than 10,000," he said.
While there has been no clarity yet on how many people lost their lives in Uttarakhand floods, conflicting figures are emerging about the number of missing people also. Uttarakhand Chief Minister Vijay Bahuguna on Sunday claimed that as many as 3000 people could be missing in the floods but the NDMA pegged the figure at 1800.

"After compiling the data, I've been informed that around 3000 people are missing. If a person is not found in 30 days, the state government will give compensation to the family. About 1335 villages still have no connectivity or aid," Bahuguna said.
The Chief Minister also said a team of 200 people has been formed, including doctors, which will take DNA samples of the dead bodies found. Bahuguna added that out of 4200 villages, connectivity has been restored in 2865 villages. Relief material is being provided through choppers to rest of the 1335 villages, he said. He further clarified that there are no report of an epidemic anywhere.
The NDMA Vice Chairman said that among the 1500 people who are stranded at various parts of Uttarakhand, there are many locals also. "According to the figures 1,07,670 people have been rescued so far. The road between Badrinath and Rambada has been repaired while a stretch in Lambagad is being repaired," he added. The road from Joshimath to Govindghat has now been restored and pilgrims are being evacuated on foot. But there is confusion over the number of pilgrims on ground.
The rescue operations in Uttarakhand are set to wind by Monday and the focus of the security forces has shifted on saving 2000 people, who are still stuck in the higher reaches. However, evacuated pilgrims claim that far greater number of pilgrims are stranded than what the officials have been stating.
According to the Indian Air Force, 842 people were rescued from Badrinath on Saturday even as air sorties were stalled briefly due to bad weather and many pilgrims in Badrinath were evacuated on foot through a newly constructed foot track in Govindghat valley. Harsil was fully evacuated on Saturday.
Meanwhile, the India Meteorological Department (IMD) has claimed it issued several advisories to the Uttarakhand government, warning it about the massive landslides and rains that have ravaged the state, killed hundreds of people and swept away houses.
"We had issued warnings on June 14 and since then we have been regularly issuing advisories. The warnings were even published in newspapers and a press release was also issued," Uttarakhand MeT department Director Anand Sharma said.
A Congress leader on Sunday claimed there was "poor coordination" among the rescue teams in Uttarakhand. "There was poor coordination in the rescue operations. Authorities in one area did not know the progress of operations in other areas. I kept asking the state authorities including the Chief Minister for immediate air support. Speedy action by the state government would have been effective," Pradeep Tamta said.

Ammonia

Documentation for Immediately Dangerous To Life or Health Concentrations (IDLHs)


Ammonia

CAS number: 7664-41-7
NIOSH REL: 25 ppm (18 mg/m3) TWA, 35 ppm (27 mg/m3) STEL
Current OSHA PEL: 50 ppm (35 mg/m3) TWA
1989 OSHA PEL: 35 ppm (27 mg/m3) STEL
1993-1994 ACGIH TLV: 25 ppm (17 mg/m3) TWA, 35 ppm (24 mg/m3) STEL
Description of substance: Colorless gas with a pungent, suffocating odor.
LEL: 15% (10% LEL, 15,000 ppm)
Original (SCP) IDLH: 500 ppm
Basis for original (SCP) IDLH: The chosen IDLH is based on the statement by AIHA [1971] that 300 to 500 ppm for 30 to 60 minutes have been reported as a maximum short exposure tolerance [Henderson and Haggard 1943]. AIHA [1971] also reported that 5,000 to 10,000 ppm are reported to be fatal [Mulder and Van der Zahm 1967] and exposures for 30 minutes to 2,500 to 6,000 ppm are considered dangerous to life [Smyth 1956].
Existing short-term exposure:
1988 American Industrial Hygiene Association (AIHA) Emergency Response Planning Guidelines (ERPGs)
  • ERPG-1: 25 ppm
  • ERPG-2: 200 ppm
  • ERPG-3: 1,000 ppm
National Research Council [NRC 1987] Emergency Exposure Guidance Levels (EEGLs)
  • 1-hour EEGL: 100 ppm
  • 24-hour EEGL: 100 ppm
U.S. Navy Standards [U.S. Bureau of Ships 1962] Maximum allowable concentrations (MACs):
  • Continuous exposure (60 days): 25 ppm
  • 1 hour: 400 ppm
ACUTE TOXICITY DATA
Lethal concentration data:
SpeciesReferenceLC50(ppm)LCLo(ppm)TimeAdjusted 0.5-hr LC (CF)Derived Value
RatAlarie 198140,300-----10 min23,374 ppm (0.58)2,337 ppm
RatAlarie 198128,595-----20 min23,448 ppm (0.82)2,335 ppm
RatAlarie 198120,300-----40 min23,345 ppm (1.15)2,335 ppm
RatAlarie 198111,590-----1 hr16,342 ppm (1.41)1,634 ppm
RatBack et al. 19727,338-----1 hr10,347 ppm (1.41)1,035 ppm
MouseBack et al. 19724,837-----1 hr6,820 ppm (1.41)682 ppm
RabbitBoyd et al. 19449,859----- 1 hr13,901 ppm (1.41)1,309 ppm
CatBoyd et al. 19449,859----- 1 hr13,901 ppm (1.41)1,309 ppm
RatDeichmann and Gerarde 19692,000-----4 hr5,660 ppm (2.83) 566 ppm
MammalFlury 1928-----5,0005 min2,050 ppm (0.41)205 ppm
MouseKapeghian et al. 19824,230-----1 hr5,964 ppm (1.41)596 ppm
HumanTab Biol Per 1933-----5,0005 min 2,050 ppm (0.41)205 ppm
*Note: Conversion factor (CF) was determined with "n" = 2.0 [ten Berge et al. 1986]. Other animal data:RD50 (mouse), 303 ppm [Appelman et al. 1982].
Other human data: The maximum short exposure tolerance has been reported as being 300 to 500 ppm for 0.5 to 1 hour [Henderson and Haggard 1943]. A change in respiration rate and moderate to severe irritation has been reported in 7 subjects exposed to 500 ppm for 30 minutes [Silverman et al. 1946].
Revised IDLH: 300 ppm
Basis for revised IDLH: The revised IDLH for ammonia is 300 ppm based on acute inhalation toxicity data in humans [Henderson and Haggard 1943; Silverman et al. 1946].
REFERENCES:
  1. AIHA [1971]. Anhydrous ammonia. In: Hygienic guide series. Am Ind Hyg Assoc J 32:139-142.
  2. Alarie Y [1981]. Dose-response analysis in animal studies: prediction of human responses. Environ Health Perspect 42:9-13.
  3. Appelman LM, ten Barge WF, Reuzel PGJ [1982]. Acute inhalation toxicity study of ammonia in rats with variable exposure periods. Am Ind Hyg Assoc J 43:662-665.
  4. Back KC, Thomas AA, MacEwen JD [1972]. Reclassification of materials listed as transportation health hazards. Wright-Patterson Air Force Base, OH: 6570th Aerospace Medical Research Laboratory, Report No. TSA-20-72-3, pp. A-172 to A-173.
  5. Boyd EM, MacLachlan ML, Perry WF [1944]. Experimental ammonia gas poisoning in rabbits and cats. J Ind Hyg Toxicol 26:29-34.
  6. Deichmann WB, Gerarde HW [1969]. Trifluoroacetic acid (3FA). In: Toxicology of drugs and chemicals. New York, NY: Academic Press, Inc., p. 607.
  7. Flury F [1928]. Moderne gewerbliche vergiftungen in pharmakologisch-toxikologischer hinsicht (Pharmacological-toxicological aspects of intoxicants in modern industry). Arch Exp Pathol Pharmakol 138:65-82 (translated).
  8. Henderson Y, Haggard HW [1943]. Noxious gases. 2nd ed. New York, NY: Reinhold Publishing Corporation, p. 126.
  9. Kapeghian JC, Jones AB, Mincer HH, Verlangieri AJ, Waters IW [1982]. The toxicity of ammonia gas in the mouse. Fed Proc 41:1568 [Abstract #7586].
  10. Mulder JS, Van der Zahm HO [1967]. Fatal case of ammonium poisoning. Tydschrift Voor Sociale Geneeskunde (Amsterdam) 45:458-460 (translated).
  11. NRC [1987]. Emergency and continuous exposure guidance levels for selected airborne contaminants. Vol. 7. Ammonia, hydrogen chloride, lithium bromide, and toluene. Washington, DC: National Academy Press, Committee on Toxicology, Board on Toxicology and Environmental Health Hazards, Commission on Life Sciences, National Research Council, pp. 7-15.
  12. Silverman L, Whittenberger JL, Muller J [1946]. Physiological response of man to ammonia in low concentrations. J Ind Hyg Toxicol 31:74-78.
  13. Smyth HF Jr [1956]. Improved communication: hygienic standards for daily inhalation. Am Ind Hyg Assoc Q 17(2):129-185.
  14. Tab Biol Per [1933]; 3:231-296 (in German).
  15. ten Berge WF, Zwart A, Appelman LM [1986]. Concentration-time mortality response relationship of irritant and systematically acting vapours and gases. J Haz Mat 13:301-309.
  16. U.S. Bureau of Ships [1962]. Submarine atmosphere habitability data book. AVSHIPS 250-649-1. Rev. 1. Washington, DC: U.S. Department of the Navy, U.S. Bureau of Ships, p. 629.

Measuring Air Humidity


Measuring relative air humidity with dry and wet bulb temperatures

Air humidity can be estimated by measuring
  • the dry bulb temperature
  • the wet bulb temperature
humidity measurement dry wet bulbe temperature
Dry Bulb Temperature - Tdb - can be measured with a simple thermometer as shown above.
Wet Bulb Temperature - Twb - can be measured with a standard thermometer with some wet clothing, cotton or similar, around the bulb. Note that a continuously air flow is important to evaporate water from the wet clothing and achieve a correct wet bulb temperature.
Sufficient air movement can be achieved with a sling thermometer or similar.
Relative humidity can be estimated from the tables below or alternatively from a psyhrometric or Mollier diagram.

Temperature in Fahrenheit

Relative Humidity - RH (%)
Difference Between Dry Bulb
and Wet Bulb Temperatures
 Tdb - Twb
(oF)
Dry Bulb Temperature - Tdb (oF)
60 64 68 72 76 80 84 88
1 94 95 95 95 96 96 96 96
2 90 90 90 91 91 92 92 92
3 84 85 85 86 87 88 88 89
4 78 80 81 82 83 84 84 85
5 73 75 76 78 79 80 80 81
6 68 70 72 73 75 76 77 78
7 63 66 67 69 71 72 73 74
8 58 61 63 65 67 68 70 71
9 54 57 59 61 63 65 66 68
10 49 52 55 57 59 61 63 64
dry and wet bulb temperature - relative moisture diagram degrees fahrenheit

Temperature in Celsius

Relative Humidity - RH (%)
Difference Between Dry Bulb
and Wet Bulb Temperatures
 Tdb - Twb
(oC)
Dry Bulb Temperature - Tdb (oC)
15 18 20 22 25 27 30 33
1 90 91 91 92 92 92 93 93
2 80 82 83 84 85 85 86 87
3 71 73 75 76 77 78 79 80
4 62 65 67 68 70 71 73 74
5 53 57 59 61 64 65 67 69
6 44 49 52 54 57 59 61 63
7 36 42 45 47 51 53 55 58
8 28 34 38 41 45 47 50 53
9 21 27 31 34 39 41 45 48
10 13 20 25 28 33 36 40 43
dry and wet bulb temperature - relative moisture diagram degrees celsius

Refrigerants - Environment Properties

Refrigerants - Ozone Depletion (ODP) and Global Warming Potential (GWP)

Common refrigerants and Ozone Depletion Potential (ODP) and Global Warming Potential (GWP) are indicated below.
  • Ozone Depletion Potential (ODP) of a chemical compound is the relative amount of degradation  it can cause to the ozone layer
  • Global Warming Potential (GWP) is a measure of how much a given mass of a gas contributes to global warming. GWP is a relative scale which compares the amount of heat trapped by greenhouse gas to the amount of heat trapped in the same mass of Carbon Dioxide. The GWP of Carbon Dioxide is by definition 1. Be aware that GWPs are highly controversial.
Refrigerant Ozone Depletion Potential
(ODP)
Global Warming Potential
(GWP)
R-11 Trichlorofluoromethane 1.0 4000
R-12 Dichlorodifluoromethane 1.0 2400
R-13 B1 Bromotrifluoromethane 10
R-22 Chlorodifluoromethane 0.05 1700
R-32 Difluoromethane 0 650
R-113 Trichlorotrifluoroethane 0.8 4800
R-114 Dichlorotetrafluoroethane 1.0 3.9
R-123 Dichlorotrifluoroethane 0.02 0.02
R-124 Chlorotetrafluoroethane 0.02 620
R-125 Pentafluoroethane 0 3400
R-134a Tetrafluoroethane 0 1300
R-143a Trifluoroethane 0 4300
R-152a Difluoroethane 0 120
R-245a Pentafluoropropane 0
R-401A (53% R-22, 34% R-124, 13% R-152a) 0.37 1100
R-401B (61% R-22, 28% R-124, 11% R-152a) 0.04 1200
R-402A (38% R-22, 60% R-125, 2% R-290) 0.02 2600
R-404A (44% R-125, 52% R-143a,  R-134a) 0 3300
R-407A (20% R-32, 40% R-125, 40% R-134a) 0 2000
R-407C (23% R-32, 25% R-125, 52% R-134a) 0 1600
R-502 (48.8% R-22, 51.2% R-115) 0.283 4.1
R-507 (45% R-125, 55% R-143) 0 3300
R-717 Ammonia - NH3 0 0
R-718 Water - H20 0
R-729 Air 0
R-744 Carbon Dioxide - CO2 1*
*  CO2 is the GWP reference

Water Delivery Flow Velocities

Water Delivery Flow Velocities

 Required flow velocities in water transport systems - on the delivery side of the pump

As a rule of thumb the following velocities can be used in design of piping and pumping systems for water:
Pipe Dimension Water
inches mm m/s ft/s
1 25 1 3.5
2 50 1.1 3.6
3 75 1.15 3.8
4 100 1.25 4
6 150 1.5 4.7
8 200 1.75 5.5
10 250 2 6.5
12 300 2.65 8.5

Pipes and Tubes - Recommended Insulation Thickness

To avoid heat loss and reduced efficiency pipe work in heating systems should always be insulated. Very hot systems, like hot water and steam systems should also be insulated to avoid potential personal injuries.
The table below indicates recommended insulation thickness.
Recommended minimum Thickness of Insulation (inches)*
Nominal Pipe Size
NPS
(inches)
Temperature Range (oC)
50 - 90 90 - 120 120 - 150 150 - 230
Temperature Range (oF)
120 - 200 201 - 250 251 - 305 306 - 450
Hot Water Low Pressure Steam Medium Pressure Steam High Pressure Steam
< 1" 1.0 1.5 2.0 2.5
1 1/4" - 2" 1.0 1.5 2.5 2.5
2 1/2" - 4" 1.5 2.0 2.5 3.0
5" - 6" 1.5 2.0 3.0 3.5
> 8" 1.5 2.0 3.0 3.5
* based on insulation with thermal resistivity in the range 4 - 4.6 ft2 hr oF/ Btu in

Ideal Gas Law

Ideal Gas Law

In perfect or ideal gas the change in density is directly related to the change of temperature and pressure as expressed by the Ideal Gas Law


In perfect or ideal gas the change in density is directly related to the change of temperature and pressure as expressed by the Ideal Gas Law.

The Ideal Gas Law and the Individual Gas Constant - R

The Ideal Gas Law relates pressure, temperature, and volume of an ideal or perfect gas. The Ideal Gas Law can be expressed with the Individual Gas Constant:
p · V = m · R · T         (1)
where
p = absolute pressure (N/m2, lb/ft2)
V = volume (m3, ft3)
m = mass (kg, slugs)
R = individual gas constant (J/kg.oK, ft.lb/slugs.oR)
T = absolute temperature (oK, oR)
This equation (1) can be modified to:
p = ρ · R · T         (2)
where the density
ρ = m / V         (3)
The Individual Gas Constant - R - depends on the particular gas and is related to the molecular weight of the gas.
Equation (1) can also be modified to
p1 V1 / T1 = p2 · V2 / T2         (4)
expressing the relationship between different states for a given mass of gas.

The Ideal Gas Law and the Universal Gas Constant - Ru

The Universal Gas Constant is independent of the particular gas and is the same for all "perfect" gases. The Ideal Gas Law can be expressed with the Universal Gas Constant:
p · V = n · Ru · T         (5)
where
p = absolute pressure (N/m2, lb/ft2)
V = volume (m3, ft3)
n = is the number of moles of gas present
Ru = universal gas constant (J/mol.oK, lbf.ft/(lbmol.oR))
T = absolute temperature (oK, oR)

Example - The Ideal Gas Law

A tank with volume of 1 ft3 is filled with air compressed to a gauge pressure of 50 psi. The temperature in tank is 70 oF.
The air density can be calculated with a transformation of the ideal gas law (2) to:
ρ = p / (R · T)         (6)
ρ= [(50 (lb/in2) + 14.7 (lb/in2)) · 144 (in2/ft2)] / [1716 (ft.lb/slug.oR) · (70 + 460) (oR)]
    = 0.0102 (slugs/ft3)
The weight of the air is the product of specific weight and the air volume. It can be calculated as:
w = ρ · g · V         (7)
w = 0.0102 (slugs/ft3) · 32.2 (ft/s2) · 1 (ft3)
    = 0.32844 (slugs.ft/s2)
    = 0.32844 (lb)

Note!

The Ideal Gas Law is accurate only at relatively low pressures and high temperatures. To account for the deviation from the ideal situation, another factor is included. It is called the Gas Compressibility Factor, or Z-factor. This correction factor is dependent on pressure and temperature for each gas considered.
The True Gas Law, or the Non-Ideal Gas Law, becomes:
P · V = Z · n · R · T  (7)
where
Z = Gas Compressibility Factor
n = number of moles of gas present

Vapor and Steam Introduction to vapor and steam

 Vapor and Steam

Introduction to vapor and steam

Vapor is a gas -
there is no significant physical or chemical difference between a vapor and a gas.
  • a vapor is a substance in a gaseous state - at a condition where it is ordinarily liquid or solid
Our most common example of a vapor is steam - water vaporized during boiling or evaporation. The water vapor surrounding us in the atmosphere is invisible and is often called moist. Knowledge about moist in air is important in air-condition applications like HVAC systems and dryers. Moist air technology is called air psychrometrics.
Evaporation from fluids takes place when the liquid molecules at the liquid surface have enough momentum to overcome the intermolecular cohesive forces and escape to the atmosphere. When heat is added to the liquid the molecular momentum and the evaporation increases. A reduction of the pressure above a liquid will reduce the momentum needed for molecules to escape the liquid and increase the evaporation.
  • increasing the pressure above the liquid reduces the evaporation
This can be observed as lower boiling temperature for water at higher altitudes.
Common terms used in connection with vapor and steam:

Boiling

  • Boiling is formation of vapor bubbles within a fluid. Boiling is initiated when the absolute pressure in the fluid reaches the vapor pressure.

Saturated Vapor

  • Vapor at the temperature of the boiling point which corresponds to its pressure.

Wet Saturated Vapor

  • A wet saturated vapor carries liquid globules in suspension. A wet saturated vapor is a substance in the gaseous state which does not follow the general gas law.

Dry Saturated Vapor

  • A dry saturated vapor is free from liquid particles. All particles are vaporized - any decrease in the vapor temperature or increase in the vapor pressure, will condensate liquid particles in the vapor. A dry saturated vapor is a substance in the gaseous state which does not follow the general gas law.

Superheated Vapor

  • In superheated vapor the temperature is higher than the boiling point temperature corresponding to the pressure. The vapor can not exist in contact with the fluid, nor contain fluid particles. An increase in pressure or decrease in temperature will not - within limits - condensate out liquid particles in the vapor. Highly superheated vapors are gases that approximately follow the general gas law.

High Pressure Steam

  • Steam where the pressure greatly exceeds the atmosphere pressure.

Low Pressure Steam

  • Steam of which the pressure is less than, equal to, or not greatly above, that of the atmosphere.

The overall heat-transfer coefficient of a heat exchanger under operating conditions is reduced by fouling

Fouling and Heat Transfer

The overall heat-transfer coefficient of a heat exchanger under operating conditions is reduced by fouling 

During operation with most liquids and some gases a dirt film gradually builds up on the heat-transfer surface. The deposit is referred to as fouling.
The increased thermal resistance of the deposit can generally be obtained only from actual tests or experience. The fouling factor can be determined from the relation
Rd = 1 / Ud - 1 / U   (1)
where 
Rd = fouling factor - or unit thermal resistance of the deposit (m2K/W)
Ud = thermal conductance of heat exchanger after fouling (W/m2K)
U = thermal conductance of clean heat exchanger (W/m2K)
(1) can also be expressed as:
Ud  = 1 / (Rd + 1 / U)

Typical Fouling Factors

  • Alcohol vapors : Rd = 0.00009 (m2K/W)
  • Boiler feed water, treated above 325 K : Rd = 0.0002 (m2K/W)
  • Fuel oil : Rd = 0.0009 (m2K/W)
  • Industrial air : Rd = 0.0004 (m2K/W)
  • Quenching oil : Rd = 0.0007 (m2K/W)
  • Refrigerating liquid : Rd = 0.0002 (m2K/W)
  • Seawater below 325 K : Rd = 0.00009 (m2K/W)
  • Seawater above 325 K : Rd = 0.0002 (m2K/W)
  • Steam : Rd = 0.00009 (m2K/W)

Monitor™ economic calculations answer common questions about the cost of fouling,

Economic Calculations

Monitor economic calculations answer common questions about the cost of fouling, the benefits to be gained from cleaning and help to develop an optimum cleaning strategy.

Cleaning Economics Reports

Monitor Cleaning Economics calculations determine the effects of cleaning exchangers in the Network.  These are shown in tabular form  and include:
  • the cost of removing exchangers for cleaning
  • the savings that could be made by cleaning selected exchangers
  • the optimum cleaning cycles for each exchanger and for user-defined groups of exchangers.
In addition, one of the standard spreadsheet reports is the Fouling Cost Summary which shows the additional costs that have been incurred over a range of cases for the furnace to make up the duty lost. 

Economic Data Required

The Cleaning Economic calculations require the following data:

Globally:

  • The Fuel Cost and the Furnace Efficiency are used when generating all economic reports. 
  • The Length of Plant Run is only used in the optimum cleaning cycle report. 
  • Fuel Cost expressed in $ per unit of duty.  The default value is the Solomon value for fuel oil.
  • Furnace Efficiency. The fuel cost is divided by this value to obtain the total cost of the fuel.
  • Length of Plant Run expressed as number of days between plant shutdowns.  This is used in the optimum cleaning cycle calculation.

For each exchanger:

  • Date Last Cleaned. This is used in the optimum cleaning cycle report.
  • Days to Clean. The number of days that an exchanger will be out of service when it is removed for cleaning.  This is used in the optimum cleaning cycle report.
  • Cleaning Cost. The fixed costs (man time, cleaning materials, etc.) associated with removing and cleaning an exchanger.  This does not include additional costs incurred by the reduced Network duty.  This cost is used in the optimum cleaning cycle report.
  • Clean Fouling Factor for the exchanger when returned to service after cleaning.  This is used in the Cleaning Economics calculation and the optimum cleaning cycle report.

How Cleaning Economics are Calculated

Fouling factors are first calculated for a selected Case.  These are used to calculate temperatures for all exchangers and at the furnace inlet.

Cost of removing exchangers for cleaning

The Network is solved and the furnace run-up temperature calculated with each exchanger in turn bypassed.  This determines the effect of removing the exchangers for cleaning in terms of lost enthalpy at the furnace inlet, also expressed as $/day. The program also calculates the amount by which the throughput would have to be reduced in order to maintain the furnace inlet temperature at its previous level.

Savings from cleaning

The fouling factor of each exchanger in turn is then set to its clean value and the Network is solved to obtain the increase in duty that this would produce at the furnace inlet.  This is shown as extra throughput which could be achieved and $/day.

Optimum cleaning cycles

The above results are then used, along with fixed costs, to calculate the optimum cleaning cycles for each exchanger.  The optimum cycle is that which minimises the annualised cost of fouling. By default, each exchanger is cleaned in turn.  Combinations of exchangers to be cleaned in addition to individual exchangers are defined in the User Defined Cleaning Economics Combinations Window.


Flexible Output

MONITOR's output capabilities are extensive.  
  • You can export the PFD drawing to PowerPoint so that you can use it in a presentation. 
  • You can get results tables displayed directly on the screen.
  • You can have a summary of Reconciliation, Fouling and NFIT runs for a range of cases.
  • You can plot results from a range of cases to view trends.
Output can be produced in any combination of Units of Measurement.
Tables:   
  


Summary:
Calculation History

 


Plots:   

User-Defined Plots

Tabular Output

You can get the results of the current case displayed as a table directly on the screen.  
You can export these results to Word or to a Text file. 



Input Data Reprint

To enable you to check all your data, Monitor prints it all out at the start of the main results output.
The network data include:
  • connectivity 
  • mechanical data 
Case data include:
  • stream temperatures, pressures, flowrates and properties
  • exchanger temperatures
  • mixer temperatures
  • splitter ratios


Reconciliation

Monitor uses measured plant temperatures and flowrates to calculate heat exchanger fouling factors. The Data Reconciliation calculation identifies inconsistencies in the input data and enables you to obtain a more consistent set of data for the fouling calculation.
Reconciliation output shows the duties calculated from the supplied flowrates and temperatures for each side of target exchanger and the differences between them. It also shows the differences between the target and calculated temperatures of the  products of target mixers.
The same data are then shown after the reconciliation has been completed. The table shows by how much feed stream temperatures and flowrates and splitter ratios have been changed to achieve a reconciled data set.


Fouling

After a reprint of the input data, the fouling report shows tabular results for each type of heat exchanger in turn, followed by results for all other types of unit operation in turn. Finally, the temperatures, pressures, flows and properties are presented for all the streams in the Network. 
Heat exchanger results include:
  • Exchanger duties, clean and dirty coefficients
  • Tube and shell velocities and Reynold's Numbers
  • Mixer temperatures and duties
  • Stream temperatures, rates and properties.


Normalised Output

Normalisation is the technique Monitor uses to remove the effect of the changes in external parameters, such as crude and product variations, to determine a true picture of the degradation of network performance due to fouling alone.
The calculated fouling factors from each case are superimposed onto the feeds from a selected base case and the resultant temperatures reported.
Normalisation output includes:
  • fouling resistances used
  • exchanger exit temperatures
  • run-up stream temperature


Cleaning Economics

Cleaning Economics calculations determine the effect of cleaning exchangers in the Network and an optimum cleaning cycle for each exchanger.
Cleaning output includes:
  • The cost of removing each  exchanger as the additional fuel cost/day to make up the duty and as the loss in throughput if the duty was not made up by the furnace.
  • The increase in duty of the complete Network after each exchanger has been cleaned expressed as a reduced furnace cost to maintain current operation and an increased throughput which could be achieved if furnace duty was not reduced.
  • The Optimum Cleaning Cycle period which provides the lowest annualised cost of fouling. The savings shown are compared with the cost of cleaning once at the end of the plant run.


Splitter Optimisation

Splitter Optimisation determines splitter product ratios which maximise the heat recovery of the Network. This minimises the required furnace duty for the Network.
Optimisation output includes:
  • Initial and final enthalpy and temperature of the chosen run-up stream.
  • all exchanger inlet and outlet temperatures and flowrates at the optimum splitter setting.

Calculation Histories

This report summarises the Reconciliation and/or Fouling and/or NFIT results for all cases within a range you select. It is particularly useful for troubleshooting data errors.  
The report here shows a range of Data Reconciliation results, including some failed cases.
You can choose to display all cases or just failed cases.
 

Plotted Output


For monitoring over a time period, by far the most meaningful form of output is that presented in graphical format.
There are a number of standard, predefined reports. You may also define your own reports to include the parameters, units and/or streams that you require.
The data for the selected report are written to a text file which is then opened automatically in Excel. A plot is created for each set of data in the spreadsheet. You may then modify and save the workbook or copy plots or data into other applications.
The standard reports are:


Reconciliation

This report compares results for data reconciliation over the range of Cases. It shows:
  • the initial duty imbalance for target exchangers and the initial and final duties on the shell and tube sides for each exchanger.
  • changes in flowrate and temperature of feed streams.
        

Heat Transfer

This report contains heat transfer data for all the exchangers in the Network and any normalised furnace inlet temperatures.
For each exchanger there are plots for:
  • duty
  • fouling
  • U-values .. clean, actual and normalised
  • tube velocity
  • shell velocity
  • effectiveness


Fouling Cost

This report shows the additional costs incurred when a furnace makes up the duty lost because of fouling. 
The spreadsheet plots the following on separate worksheets:
  • The normalised furnace inlet temperature.
  • The Cost/day of the additional furnace duty required to make up for the network duty loss caused by the current level of fouling.
  • The cumulative additional furnace duty required since the start of the specified period. 
  • The cumulative fuel cost of the exchanger fouling since the start of the specified period.


Stream Temperatures

This report shows the temperatures of all streams in the Network. 
Feed streams, product streams and internal streams are presented separately and are plotted on separate worksheets.
Compare this plot of the actual furnace inlet stream temperatures with the normalised plot abov.  This shows the benefit of normalisation to give a more meaningful presentation of the true effect of fouling. 

Weight and Volume Flow Rates

These two reports show the weight and volume flowrates of all streams in the Network. Feed streams, product streams and internal streams are presented separately and are plotted on separate worksheets.
Weight Flowrates
Volume Flowrates

Pressures

The pressure at the inlet and outlet of each exchanger is listed on this report along with pressure drops. The plots for each exchanger are on separate worksheets and show:
  • Shell side inlet and outlet pressures
  • Shell side pressure drops
  • Tube side inlet and outlet pressures
  • Tube side pressure drops


User Defined Spreadsheet Outputs

If none of the standard spreadsheet reports meets your requirements, you may define your own reports.
You may specify a
  • Exchanger duty, U (actual and clean), fouling factor, velocities, Re, temperatures, MTD, LMTD and Ft.
  • Pump duty, heater and cooler temperatures and splitter ratios.
  • Stream temperatures, pressures, flowrate and liquid fraction.