FPSerrata04_05.pdf

7/27/2019 FPSerrata04_05.pdf

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GPSA ENGINEERING DATABOOK ERRATA

(2004 FPS Edition)

PAGE DESCRIPTION

18 Fig. 12 Change units for Energy conversion factor

33 Fig. 32 Change to referenced figures

1016 Fig. 1019 Reference change

1017 Eq. 104 Change equation and following example

201 Fig. 201 Add i = any component in a mixture

2032 Figs. 2063, 2064 Reference change

215 Fig. 213 Change heats of reaction


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vapor recoveryEquipment or process for the recovery of desired componentsfrom stock tan k va pors or va pors from some other source.

volatile sulfurAn obsolete term r eferring to sulfur compounds tha t w ill va-porize read ily (See sulfur).

weatheringThe evaporation of liquid caused by exposing it to the condi-tions of at mospheric temperat ure an d pressure. Pa rtia l evapo-ra tion of liquid by use of heat ma y also be called weat hering.

weathering testA GPA test for LP -gas for the determina tion of heavy compo-nents in a sam ple by evaporation under specified conditions.

weight in airWeight compared to a sta nda rd w ith no correction for air buoy-ancy.

wellheadThe assembly of fit t ings, valves, and controls located at the

surface a nd connected t o the flow lines, tubing, and casing of

the w ell so as to control the flow from th e reservoir.

wet gas(1) A gas conta ining wa ter, or a ga s wh ich has not been dehy-

dra ted. (2) A term synonym ous with rich gas. Refer to defini-

tion of "rich gas" .

Wobbe numberA number proportional to the heat input to a burner at con-

sta nt pressure. In Brit ish practice, it is the gross heating va lue

of a ga s divided by t he squa re root of its gra vity. Widely used

in Europe, together with a measured or calculated flame

speed, to determine int erchangeability of fuel ga ses.

Conversion Factors

In t hese ta bles, fa ctors for conversion, includin g conversions

to the Int erna tional S ystem of Un its (SI ), are based on ASTM

Standard for Metric Practice, E380-91. The latest edition ofthis publication should be studied for more detail on the SI

system, including definitions a nd sy mbols.

In calculat ing derived factors in th e ta bles that follow, exact

conversions w ere used, when ava ilable, ra ther t ha n th e 7-digit

round-offs listed in ASTM E380 conversion t a bles. Derived fa c-

tors given below a re rounded to the sam e number of significan t

digits a s the source factors.

In a ny conversion of fundam enta l measurement un its, some

confusion may result due t o redefinition of units used in earlier

ta bles. For exam ple, in 1959 a sma ll refinement wa s ma de in

the definition of the yard, which changed its length from

3600/3937 met er (or 1 inch = 25.4000508 mm) t o 0.9144 m

exactly (or 1 inch = 25.4 mm exa ctly). The ta bles below a rebased on the new definition, but one should be aware that

wh ere U.S. land m easurement s ar e concerned, the old relat ion-ship a pplies. Refer to ASTM E 380-91, note 13, for more det a il.

Energy Units Conversion

Confusion may arise in the definition of units for heat orenergy. In the tables below, the Btu (IT) and calorie (IT) areused. These are the hea t units r ecommended by the Int erna-tional C onference on t he P roperties of Stea m, as defined:

1 B tu (IT) = 1055.055 852 62 joule (exa ctly )1 Ca lorie (IT) = 4.186 800 joule (exact ly)

For information only, other definitions tha t ma y be usedelsewhere:

1 Bt u (Mean) = 1055.87 joule1 B tu (39F ) = 1059.67 joule1 B tu (60F ) = 1054.68 joule

1 B tu (Ther mochem ica l) = 1054.350 joule1 calorie (Mea n) = 4.190 02 joule

Velocity(Lengt h/unit of time)

ft /sec ft/min Miles/hr (U .S . S t a t ut e) m/sec m/min km/hr

1 60 0.6818182 0.3048 18.288 1.09728

0.01666667 1 0.01136364 5.08 x 103

0.3048 0.018288

1.466667 88 1 0.44704 26.8224 1.609344

3.280840 196.8504 2.236936 1 60 3.6

0.05468066 3.280840 0.03728227 0.016667 1 0.06

0.9113444 54.68066 0.6213712 0.2777778 16.66667 1

Energy

Ft -lbf Kgf-met er B tu (IT) Kilo-ca lorie (IT) H p-hr Kilow a t t -hr joule (J )

1 0.1382550 1.285068 x 103

3.238316 x 104

5.050505 x 107

3.766161 x 107

1.355818

7.233014 1 9.294911 x 103

2.342278 x 103

3.653037 x 106

2.724070 x 106

9.806650

778.1692 107.5858 1 0.2519958 3.930148 x 104

2.930711 x 104

1055.056

3088.025 426.9348 3.968321 1 1.559609 x 103

1.163 x 103

4186.8

1980000 273744.8 2544.434 641.1865 1 0.7456999 2684520.

2655224 367097.8 3412.142 859.8452 1.341022 1 3600000.

0.7375621 0.1019716 9.478171 x 104

2.388459 x 104

3.725061 x 107

2.777778 x 107

1

FIG. 1-2

Conversion Factor Tables

1-8


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Fa ctors U nit s

Ma ss Vol Ma ss Vol Ma ss Vol Ma ss Vol Ma ss Fig.#

U nits of Mea surement lb/hr scf/hr lb/hr scf/hr lb/hr gph lb/hr gph lb/hr

Squa re Root of Differential hw

Squa re Root of Sta t ic Pressure P f

Orifice Fa ct or (KE Y) Fn (Fc+ F sl)

3-13

P ressure B a se Fa ct or Fpb 3-4

Flow ing Tempera t ure Fa ctor F tf 3-4

Tempera t ure Fa ct or F tm 3-1

Temp Correct ion Fa ctor (Liquids) C tl 3-1

P r essu re C or rect ion Fa ct or (L iq uid s) C pl 3-4

P ressure Fa ctor Fpm 3-1

S upercompressibilit y Fa ct or Fpv 23-4

S qua re of S upercompressibility Fa ct or S 3-1

Density 3-1

Squa re Root of Density

S pecific G ra vit y Fa ct or G a s Fg 3-4

G r a vi ty -Tem per a t ur e Fa ct or L iq uid Fgt 3-4

Met er Fa ct or MF 3-1

Count (Volume) C NT 3-1

Consta nt 1.0618 1.0618

S tea m Fa ctor F s 3-27/28

E xpa nsion Fa ct or Y 3-1

Tempera t ure B a se Fa ct or F tb 3-4

Orifice Therma l E xpa nsion Fa ct or F a 3-4

Notes:

1. This guide is intended for use in obtaining a pproximate flows w hen used in conjunction with dat a contained in this section asreferenced in th e far r ight ha nd column.

2. To obta in flow, substitute areas conta ining dots with known numbers and mult iply top to bottom.

3. The number of factors used ma y vary depending on method of calculat ion in specific applicat ion, content of f lowing strea m, andindividual contra ctual a greements.

4. Factors appearing in shaded areas a re not genera l ly necessary for ca lcula t ing approximate f lows .

5. Th e fa ct or s Fpv , S, C tl , C pl , Y, an d F a must be obta ined for the specific substa nce being mea sured.

Turbine orDisplacement

Orifice

G a s

Turbine orDisplacement

Orifice

Liquid

Orifice

Steam

FIG. 3-2

Flow Calculation Guide

3-3


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Check the inside of tube section for accumulation ofgrea se, dirt, bugs, leav es, etc., a nd schedule cleaning be-fore tubes become packed with such debris.

NOISE CONSIDERATIONS

Fan noise can be elusive requiring sophisticated equipment

to measure accurately. Fan noise control must begin at theair-cooled heat exchanger design stage. Noise control, as anaft er thought, can result in a very costly fa n a nd drive compo-nent retrofit , and possible addit ion of heat tra nsfer surface oracoustic barriers. Acoustic bar riers ma y increase t he pressuredrop the fan must overcome; hence, bigger fans and morehorsepower will be required.

Sin ce noise (Sound P ressure Level) is a funct ion of tip speed,slowing fan rotat ion can reduce noise.

Unfortunately, a fans pressure capability decreases withth e squa re of the speed. Therefore, th e fans pressure capa bil-ity must increase to ma inta in the required airflow.

To increase the pressure capa bility of a fa n, the fan s solidityratio must be increased, by adding more blades, or usingblades w ith a wider chord, such a s a low-noise blade design.

Un fortunat ely, increasing t he number of blades can reduce fanefficiency.

Noise requirements are often more restrictive at night. Ifthis is a consideration, slowing the fan as ambient tempera-tur e drops using a va ria ble-speed drive can be one solution toreducing n oise. As t he nightt ime a mbient temperat ure drops,required a irflow is reduced, therefore fan speed ma y be slowedto lower noise levels.

Noise-Related Nomenclature

Decibel:

A number representing relat ive sound intensity expressedw ith respect to a r eference pressure or power level. The usua lreference for sound pressure level is of 20 micro newt ons per

squa re meter (20 /m2). A decibel is a logarit hm (bas e 10) of ara tio of the power values abbreviat ed "dB ".

Frequency:

Sound v ibra tion ra te per second in H ertz (cycles per second).

Low-Noise Fans:

A fan a ble to operate a t low speed due to its high-pressurecapability. Fan pressure capa bility is a function of its solidityratio. Therefore, a low-noise fan will generally have more orwider blades than would be required if the fan operated atnorma l tip speeds.

Octave Bands:

Noise is cat egorized by dividing it into separa te frequencyba nds of octa ves or 1/3 octa ves. G enera lly, 63, 125, 250, 500,1K, 2K, 4K a nd 8K center freq uencies are used to define noise

ba nds in H ert z (cycles/sec).Sound Power Level:

Acoustical power (energy) can be expressed logarit hmica llyin decibels with respect to a reference power, usually 10-12

wa tts. The relationship is given as: Sound P ower Level.

P WL = 10 lo g

W

1012watts

Eq 10-3

Sound power level cannot be mea sured directly but must becalculated from sound pressure levels (SPL) dB. In metricterms, this is known as L w.

Sound pressure level, known a s SP L, or Lp in metric termi-nology, is the audible noise given in decibels that relates tointensity at a point some dista nce from t he noise source. It can

be related to octave bands or as an overall weighted leveldB (A).

Weighted sound levels rela te t he decibel (loudness) to a fr e-quency. Ears can easily pick up high-frequency noises (bothintensity an d direction) but ar e relatively insensitive to low-frequ ency noise. For a stereo system h igh-frequency speakersmust be very carefully locat ed in a room for best results, butlow-frequ ency bass speakers ca n be placed an yw here, even outof sight.

There are three basic weighting systems: A, B and C. The"A" system, dB (A), most closely relates t o our ea r, the "B " sys-

FIG. 10-18

Air Static-Pressure Drop

Correction factor

w h e n =

w

0.14

(See F ig. 10-13)

Correction

Factor, 1. Hydroca rbon va por ; st ea m; wa ter 1.0

2. Hy drocarbon liquids (18 to 48 API), MEA/DE Asolutions

0.96

3. Wa ter/glycol solut ions; hea t t ra nsfer fluids 0.92

4. L ube oils ; h ea vy pet r oleu m fr a ct ion s (10 to 18 AP I ) 0. 85

When N r


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tem, dB(B), has some specific uses a nd t he "C " system, dB (C),is considered unweighted.

The dB(A) is the most common weighting system. It ex-presses sound levels wit h a single number instead of ha vingto specify th e noise of ea ch octa ve band .

Note tha t t he sound ran ge of ACH Es (at close range) is typi-cally betw een 80 and 105 dB (A).

ACHE Noise

Whether the concern is for overall plant noise or the noiseexposure of plant workers in t he vicinity of the fan s, a differentty pe of noise specificat ion must be used.

Overall, noise limitations from an ACHE are typically asound power level (P WL) specificat ion for each u nit. This lim -its the contribution of each unit (typically two fans) to theplant noise as a whole. This is usua lly needed w here noise atthe plan t boundar y is considered. Contr ibutions of each partof the plant must be carefully controlled if overall plant noiseis limit ed. PWLs can be expressed a s w eighted level dB (A) orsometimes even by limita tions on each octa ve band.

If worker protection is the main concern, a limitation ofsound pressure level at 3 ft or 1 m below the bund le will SUREDEO\ be imposed as " SP L dB (A) at 3 ft " . The OSH A limita tionis 90 dB (A) for eight -hour exposure, but 85 dB (A) dow n t o 80dB (A) is not uncommon.

Predicting Fan Noise

Each fan manufacturer has proprietary equations for pre-dicting fan noise. AP I G uidelines use the general formula:

P WL = 56 + 30 log

FP M

1000

+ 10 log HP Eq 10-4

This calculates PWL as dB(A)

Proprietary noise equations are based on actual tests various speeds and operating conditions considering the folowing effects:

Fan diam eter

Fan tip speed

B lade Type

Bla de pitch angle

Inlet conditions

Horsepower

Note: Logs a re common logs (base 10).

For example:

14 ft fa n

237 RP M (10,424 FP M tip s peed)

25.1 HP

Find sound power level

P WL= 56 + 30 log 10.4 + 10 log 25.1

= 100.5 dB (A)

When considering mult iple noise sources (fans) use trelation:

P WLN = PWL + 10 log N Eq 10

The sound power level for 2 adja cent fa ns is th e PWLone fan plus 10 log 2 or P WL2 = P WL + 3.

A doubling of th e noise source ad ds 3 dB.

Noise attenua tes with dista nce by the equa tion:

SP L (at dista nce R) = P WL - 20 log R Eq 10

Where R is in feet from t he cent er of the source. MeasuR as a " line of sight" dista nce.

Altitude above Sea Level Barometer Atmospheric Pressure

meters feet mm Hg abs. in Hg abs. kPa (abs) psia

0 0 760.0 29.92 101.325 14.696

153 500 746.3 29.38 99.49 14.43

305 1000 733.0 28.86 97.63 14.16

458 1500 719.6 28.33 95.91 13.91

610 2000 706.6 27.82 94.18 13.66

763 2500 693.9 27.32 92.46 13.41

915 3000 681.2 26.82 90.80 13.17

1068 3500 668.8 26.33 89.15 12.93

1220 4000 656.3 25.84 87.49 12.69

1373 4500 644.4 25.37 85.91 12.46

1526 5000 632.5 24.90 84.32 12.23

1831 6000 609.3 23.99 81.22 11.78

2136 7000 586.7 23.10 78.19 11.34

2441 8000 564.6 22.23 75.22 10.91

2746 9000 543.3 21.39 72.39 10.503050 10 000 522.7 20.58 69.64 10.10

Reprinted with permission of J ohn M. Cam pbell and Company.

FIG. 10-20

Altitude and Atmospheric Pressures8

10-17


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20-1

SECTION 20

Dehydration

Natural gas and associated condensate are often producedfrom the reservoir saturated (in equilibrium) with water. Inaddition, the gas and condensate often contain CO2 and H2Swhich might require removal. This is frequently accomplishedwith aqueous solutions such as amines, potassium carbonate,etc. which saturate the gas or condensate with water. Liquidhydrocarbons may also contain water downstream of producttreaters or upon removal from underground storage.

Dehydration is the process used to remove water from naral gas and natural gas liquids (NGLs), and is required to:

prevent formation of hydrates and condensation of fwater in processing and transportation facilities,

meet a water content specification, and

prevent corrosion

A = area, ft

2

B = constant in Equation 20-11

C = constant in Equation 20-11

Cp = heat capacity, Btu/(lb F)

Cg = gravity correction factor for water content

Cs = salinity correction factor for water content

Css = saturation correction factor for sieve

CT = temperature correction factor

D = diameter, ft

d = depression of the water dewpoint or the gas hy-drate freezing point, F

EOS = Equation of State

Fs = sizing parameter for packed towers,

lb/(ft sec)G = mass velocity, lb/(ft2 hr)

H = enthalpy, BTU/lb H = latent heat of vaporization, Btu/lb

Kvs = vapor/solid equilibrium K-value

L = length of packed bed, ft

Lg = glycol flow rate, U.S. gal./hr

LMTZ = length of packed bed mass transfer zone, ft

Ls = length of packed bed saturation zone, ft

m = mass flow rate, lb/hr

MTZ = mass transfer zone

MW = molecular weight

MWI = molecular weight of inhibitor

N = number of theoretical stages

P = pressure, psia

P = pressure drop, psi

q = actual gas flow rate, ft3/minQ = heat duty, Btu/hr

Qc = reflux condensing heat duty, Btu/gal.

Qhl = regeneration heat loss duty, Btu

Qr = total regeneration heat duty, Btu/gal.

Qs = sensible heat, Btu/gal.

Qsi = duty required to heat mole sieve to regenerationtemperature, Btu

Qst = duty required to heat vessel and piping toregeneration temperature, Btu

Qtr = total regeneration heat duty, Btu

Qv = vaporization of water heat duty, Btu/gal.Qw = desorption of water heat duty, Btu

Ss = amount molecular sieve reqd in saturation zone,

t = thickness of the vessel wall, in.

T = temperature, F

Trg = regeneration temperature, F

v = vapor velocity, ft/sec

V = superficial vapor velocity, ft/min

w = water rate, lb/hr

W = water content of gas, lb/MMscf

Wbbl = water content of gas, bbl/MMSCF

Wr = water removed per cycle, lb

x = mole fraction in the liquid phase

X = mass fraction in the liquid phase

y = mole fraction in the gas phasez = compressibility factor

= specific gravity

= viscosity, cp

= density, lb/ft3

Subscripts

i = inlet

o = outlet

l = liquid

v = vapor

t = total

CO2 = carbon dioxide

H2S = hydrogen sulfide

HC = hydrocarbons = solid phase

L = lean inhibitor

R = rich inhibitor

I = inhibitor

H2O = water

H = hydrate

rg = regeneration

f = feed

p = permeate

i = any component in a mixture

FIG. 20-1

Nomenclature


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Example 20-1130 MMscf/d of a 0.65 sp gr na tur a l ga s enter sa TEG conta ctor a t 600 psia a nd 100 F. Outlet wa ter contentspecifica tion is 7 lb H 2O/MMscf and t he TEG circulat ion rat eis 3 g a l TE G /lb H 2O. Est imate the contactor diameter andnumber of bubble cap trays or height of structured packingrequired to meet t his requirement. Assume z = 0.92.

Solutions Steps:

1. Est imat e required TEG concentrat ion from Fig. 20-68

H 2O Dewpoint = 24F, w hich from Fig. 20-4 is equiva -lent to a w at er content of 7 lb H 2O/MMs cf @ 600 psia )

Assume a 10 F a pproach t o equilibrium

@ T = 100 F, lean TEG concentr a tion 98.8 w t%

2. Est imat e number of theoret ica l s tages .

Ca lculat e wat er removal efficiency

Win Wout

Win =

90 7

90 = 0.922

Fr om Fig. 20-70 (N = 1.5) a t 3 ga llon TEG /lb H 2O and99.0 w t%TEG

(Win Wout )/Win = 0.885

Fr om Fig. 20-71 (N = 2.0) a t 3 ga llon TEG /lb H 2O and99.0 w t%TEG

(Win Wout )/Win = 0.925use N = 2.0

2 theoretical stages 8 bubble cap t ray s @ 24 inch t rayspacing

FIG. 20-61

Hydrate Inhibition with Methanol:

Hammerschmidt vs. Experimental Data28

FIG. 20-62


Nielsen & Bucklin vs. Experimental Data28

FIG. 20-63


Nielsen & Bucklin26

vs. Experimental Data29

FIG. 20-64


Maddox et al.27

vs. Experimental Data29

20-32


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Chemistry The overall equilibrium r eactions a pplica-ble for H 2S a n d C O2 and primary a nd secondary amines areshown below w ith a primary amine 9. A qua litat ive estima tionof the velocity of the reaction is given.

For hydrogen sulfide removal

RN H 2 + H 2S RNH 3+

+ H S

Fas t Eq. 21-1

RNH 2 + H S

RNH 3+

+ S

Fas t Eq. 21-2

The overall rea ctions betw een H 2S a nd a mines are s impsince H 2S rea cts direct ly and ra pidly w ith a ll amines to forth e bisulfide by E q. 21-1 and th e sulfide by E q. 21-2.

For carbon dioxide removal

2 RNH 2 + C O2 RN H 3+

+ R NH C OO

Fas t Eq. 21

RNH 2 + C O2 + H 2O RNH 3+

+ H C O3

Slow Eq. 21

RNH 2 + H C O3 RN H 3

+ + C O3 Slow Eq. 21

MEA DEA(9)

DGA

Sulfinol MDEA(9)

Acid ga s picku p, scf/ga l @ 100 F,normal range

(2)3.14.3 6.7 7.5 4.77.3 417 37.5

Acid gas pickup, mols/mol a min e,normal range

(3)0.330.40 0.200.80 0.250.38 NA 0.200.80

Lean solut ion residual acid gas,mol/mol am ine, normal ra nge

(4)0.12 0.01 0.06 NA 0.0050.01

Rich solution acid gas loading,mol/mol am ine, normal ra nge

(3)0.450.52 0.210.81 0.350.44 NA 0.200.81

Solution concentr at ion, wt%, normalra nge 1525 3040 5060

3 comps.,va r ies 4050

Approximat e reboiler hea t dut y,B tu/gal lean solution

(5)1,0001,200 8401,000 1,1001,300 350750 800900

Steam heated reboiler tube bundle,approx. average heat f lux,

Q/A = B tu /hr -ft2 (6)

9, 00010,000 6,3007,400 9, 00010,000 9,00010,000 6,3007,400

Direct fired r eboiler fire tube, aver-age heat f lux,

Q/A = B tu /hr -ft2 (6)

8, 00010,000 6,3007,400 8, 00010,000 8,00010,000 6,3007,400

Reclaimer, steam bund le or fire tube,average heat f lux,

Q/A = B t u/hr -ft2 (6) 69 NA(7) 68 NA NA(7)

Reboiler temperature, normal operat-ing range, F

(8)225260 230260 250270 230280 230270

Heats of react ion;(10)

approximate:B tu /lb H 2S 610 555 674 NA 530

B tu /lb C O2 825 730 850 NA 610

NA not a pplicable or not a vaila ble

NOTES:

1. These data alone should not be used for specific design purposes. Ma ny design factors must be considered for actua l plant design.

2. Dependent upon acid gas partia l pressures and solution concentra tions.

3. Dependent upon acid gas part ial pressures and corrosiveness of solution. Might be only 60%or less of value shown for corrosive systems.

4. Var ies with stripper overhea d reflux ra tio. Low residual acid gas contents require more stripper trays a nd/or higher reflux ra tios yielding largerreboiler dut ies.

5. Varies w ith st ripper overhead reflux ratios, rich solution feed temperature t o stripper a nd reboiler temperature.

6. Maximum point h eat flux can rea ch 20,00025,000 Btu/hr-ft2

at highest flame temperature at the inlet of a direct fired fire tube. The most sat isfactorydesign of firetube heating elements employs a zone by zone calculation based on thermal efficiency desired and limiting the maximum tube walltempera ture a s required by the solution to prevent therm al degra dat ion. The avera ge heat flux, Q/A, is a result of these calculations.

7. Reclaimers are not used in DEA and MDEA systems.

8. Reboiler tempera tures a re dependent on solution conc. flar e/vent line back pressure a nd/or residual C O2 content required. It is good practice to opera tethe reboiler at as low a temperature as possible.

9. According t o Total.

10. B.L. Cry nes an d R.N. Maddox, Oil Ga s J., p. 65-67, Dec. 15 (1969). The heat s of reaction var y w ith a cid gas loading a nd solution concentra tion. Thevalues shown ar e average

10.

FIG. 21-3

Approximate Guidelines for Amine Processes1

21-5

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