redesign of well pad "x" geothermal separator with demister ...

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REDESIGN OF WELL PAD "X" GEOTHERMAL SEPARATOR WITH DEMISTER PAD TO

INCREASE SEPARATOR EFFICIENCY TO GET MAXIMUM STEAM AND BRINE

SEPARATION IN THE FIELD "Y"

Akhmad Sofyan1, Hari Sumantri Aka1, Muhammad Bobi Ermanda1

1Polytechnic of Energy and Minera Akamigas, Jalan Gajah Mada No. 38, Blora, Central Java, Indonesia

E-mail: [email protected] , [email protected] , [email protected]

Keywords: Re-design, Surface Facilities, Separator, Demister Pad, Hysys 8.8 Simulator, Separator Efficiency

ABSTRACT

The "Y" Geothermal Field has a geothermal power plant with a capacity of 60 MWe. This field produces two-phase fluid dominated by

water. One of the wells in this field, the Well Pad "X", has experienced an increase in production from 4 MWe to 9 MWe, making the

production equipment capacity less to cope with the increase in production. Therefore, a redesign for surface facilities at this well must be

carried out, so that the quality of the steam entering the turbine becomes better. The re-design will be done is a separator with a demister

pad added so that the separation results become more optimal. In planning the separator requires data in the field such as production rate,

pressure, temperature, enthalpy and previous design data. From the data obtained in the field, Well Pad "X" produces two-phase fluid at

84.5 tons / hour with a steam fraction of 93.6%, so that the steam produced is 79.1 tons / hour and brine at 5.4 tons /hour. The data is then

entered into the simulator in accordance with the length of the pipe in the field to simulate the flow from the well to the main steam using

the Hysys 8.8 simulator and a safety factor of 50%. Simulator Hysys 8.8 uses the ASME Steam as a property package for this simulation.

From the simulation results obtained energy balance which will be used to redesign surface facilities. The re-design of the separator

dimensions is 2.5 m (diameter) and 4.8 m (height) and the demister pad dimension is 1.6 m (diameter) and 200 mm (thickness). Geothermal

fluid entering the separator is 126.8 tons / hour, after being separated it is obtained a steam flow rate of 119.1 tons / hour and a brine flow

rate of 7.6 tons / hour or fraction. Whereas the result of separator efficiency using demister pad is 99.9997% and carry out is 0.0003%, so

that the efficiency of separator with demister pad is better than ordinary separator which has 99% efficiency.

1. INTRODUCTION

Geothermal Field "Y" is managed by PT. Geo Dipa Energi by generating electricity of 60 MWe from the number of wells that have been

available. The production wells in this field produce two-phase fluids in the form of steam and brine, each of the other has a different

capacity to generate electricity. In addition, there are several wells that have increased their power generation capacity. One of the wells

that experienced an increase in production was the Well Pad "X", whose initial production was 4 MWe to 9 MWe.

The increase in capacity at the Well Pad "X" means that the capacity of the surface equipment must be increased because the initial design

of this well equipment is for a 4 MWe well capacity. Therefore, it is necessary to re-design surface facilities for a larger capacity so that the

steam yield obtained is better and the equipment becomes safer. The surface facilities that were redesigned were the size of the separator

and the demister pad. This separator must be designed properly so that the steam produced will be more maximal. On the surface facility

design calculation requires data in the field such as production rate, pressure, temperature, enthalpy, and previous design data.

Therefore, the writer in this thesis will re-design the optimal separator so that the Well Pad "X" can generate electricity maximally.

2. BASIC THEORY

2.1. Geothermal Power Plant Type of Steam Cycle Result of Separation (Separated Cycle)

If the geothermal fluid comes out of the wellhead as a mixture of two-phase fluids (vapor phase and liquid phase), then the first separation

process is carried out in the fluid drain the fluid into the separator so that the vapor phase will be separated from the liquid phase. The

fraction of steam produced from this separator is then streamed to the turbine. Because the steam used is the result of separation, this energy

conversion system is called the separated steam cycle. Figure 1 shows the process of generating electricity from a geothermal field that

produces a two-phase fluid, namely a mixture of steam and brine. The fluid from the well is separated into a steam and brine phase in a

separator where steam has flowed into the turbine and brine is injected back under the surface (N. M. Saptadji, 2018).

Figure 1: Geothermal Power Plant Type of Steam Cycle Result of Separation (Separated Cycle)

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Sofyan, Aka, and Ermanda

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2.2. Geothermal Separator

If the well fluid is a vapor-water mixture (two-phase fluid), then steam and water are separated in a separator. The separator that is often

used is the curved "U" as shown in Figure 2. The vapor-water mixture when flowed through a pipe with a bend of 180oC is expected to get

a very high centrifugal force that throws the fluid towards the wall so that it will separate into a vapor phase and a liquid phase. The water

will be thrown against the wall while the steam will fill the center of the pipe. Separation in this way is not good, because the water content

in the steam coming out of the separator is still high where the dryness is only around 50-60%. Figure 2 shows the "U" Shaped Separator

and Webre Cyclone Separator. Various types of separators have been made, but the most frequently used today is the Webre cyclone

separator, because it is the cheapest and most efficient. The spiral inlet provides a higher separation efficiency. With this type of separator,

the steam coming out of the separator can have very high dryness, more than 99%. The efficiency of this separator decreases if the velocity

of the fluid entering the separator is more than 50 m / sec (N. M. Saptadji, 2018).

Figure 2: Separators used in geothermal fields (N. M. Saptadji, 2018)

2.3. Geothermal Separator Sizing

In general, the design criteria used as the basis for designing a Well Pad Separator are as follows.

2.3.1. Vapor Superficial Velocity Determination

Superficial Velocity Vapor is calculated by the following equation:

Uv max = Kv (( l – v )/ v )0,5 ............................................................................................................ (2-1)

Where:

Uv max : Superficial Velocity (ft/s)

Kv : Vapor Velocity factor

l : Brine density (lb/ft³)

v : Steam density (lb/ft³)

(ASME VIII, 2007)

2.3.2. Determination of K Factor

The determination of the K value depends on the type and length of the separator, here is Table 1 to determine the K factor value (12J,

1989):

Value of K factor based on the type and length of the separator

Table 1: Value of K factor based on the type and length of the separator

Types of Separator Separator Length (ft) K Factor

Vertical 5 0.12 – 0.24

10 0.18 – 0.35

Horizontal 10 0.4 – 0.5

Other lengths 0.4 – 0.5 x (L/10)0.36

Spherical All 0.2 – 0.35

2.3.3. Determination of the Type of Separator

The recommended separator for Well Pads in geothermal areas is the vertical steam-water separator using a demister pad.


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2.3.4. Geothermal Separator Sizing Procedure for Vapor-Liquid Separators

Vapor-liquid separator vessels usually serve two functions. Their primary job is to separate vapor and liquid, but they may also serve as

liquid surge drums. The basic design principle is to provide a sufficiently low velocity so that vapor and liquid will separate.

The designer must also design the surging volume properly. As a general rule, a vessel such as an atmospheric tower accumulator which

is to provide a large surge volume will be a horizontal drum. A vessel such as a compressor interstage knockout drum which provides only

a small surge volume will be a vertical vessel.

The vapor velocity factor chart is based on 5% of the liquid being entrained with the vapor. This is adequate for normal design. Where

entrainment must be less, a mist eliminator section is recommended. This will guarantee maximum entrainment of 1%. These devices are

used mainly in compressor suction drums and product gas separators. (Frank L. Evans, 1980)

Calculation Method-Vertical Drum

Step 1. Calculate the vapor-liquid separation factor

(𝑊𝑙/𝑊𝑙)√𝜌𝑣/ 𝜌𝑙 .............................................................................................................................................................. (2-2)

Where

Wl = Liquid flow rate, lb/sec

Wv = vapor flow rate, lb/sec and

𝜌𝑣/ 𝜌𝑙 = vapor and liquid densities, lb/cu.ft

Step 2. From Figure 3, find the design vapor velocity factor, Kv, and calculate the maximum design vapor velocity.

(𝑢𝑣)𝑚𝑎𝑧 = 𝐾𝑣√(𝜌𝑙 − 𝜌𝑣)/𝜌𝑣 , ft/sec .............................................................................................................................. (2-3)

Note that this is a design velocity and should not be derated

Step 3. Calculate the minimum vessel crossectional area.

𝐴𝑚𝑖𝑛 = 𝑄𝑣/(𝑢𝑣)𝑚𝑎𝑥 , sq.ft ............................................................................................................................................. (2-4)

Where Qv = vapor flow rate, cu.ft./sec.

Step 4. Set vessel diameter based on 6-in. increaments

𝐷𝑚𝑖𝑛 = √4(𝐴𝑚𝑖𝑛)/𝜋, ft .................................................................................................................................................. (2-5)

D = Dmin to next largest 6 in

Figure 3: Design vapor velocity factor for vertical vapor-liquid separators at 85% of flooding

Step 5. Estimate the vapor-liquid inlet nozzle based on the following velocity criteria:

(𝑢𝑚𝑎𝑥)𝑛𝑜𝑧𝑧𝑙𝑒 = 100√𝜌𝑚𝑖𝑥, ft/sec ................................................................................................................... (2-6)

(𝑢𝑚𝑖𝑛)𝑛𝑜𝑧𝑧𝑙𝑒 = 60√𝜌𝑚𝑖𝑥, ft/sec ...................................................................................................................... (2-7)

Step 6. Make preliminary vessel sizing as in Figure 4.

Step 7. Select the appropriate full surge volume in seconds. Calculate the required vessel volume:

𝑉 = 𝑄𝑙/(𝑑𝑒𝑠𝑖𝑔𝑛 𝑡𝑖𝑚𝑒 𝑡𝑜 𝑓𝑖𝑙𝑙), cubic feet ....................................................................................................... (2-8)

Where Ql = liquid flow rate, cubic feet per second.


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Then liquid height is

𝐻𝑙 = 𝑉(4/𝜋𝐷2) ............................................................................................................................................... (2-9)

Step 8. Check geometry. (Hl - Hv)/D must be between 3 and 5.

For small volumes of liquid, it may be necessary to provide a more liquid surge than is necessary to satisfy the L/D > 3. Otherwise,

these criteria should be

If the required liquid surge volume is greater than that possible in a vessel having L/D < 5, a horizontal drum must be provided.

(Frank L. Evans, 1980)

Figure 4: An example is given to show how to calculate the dimension of a vertical separator.

2.4. The Enginered Mist Eliminator

Mist elimination, or the removal of entrained liquid droplets from a vapor stream, is one of the most commonly encountered processes

regardless of unit operation. Unfortunately, mist eliminators are often considered commodity items and are specified without attention to

available technologies and design approaches. The engineered mist eliminator may reduce liquid carryover by a factor of one hundred or

more relative to a standard unit, drop head losses by 50% or more, or increase capacity by factors of three or four. This manual summarizes

cost-effective approaches to reducing solvent losses or emissions, extending equipment life and maintenance cycles using proven and cost-

effective technologies and techniques. Mistermesh pad with drainage rolls. (Industries, 2016)

Figure 5: Mistermesh pad with drainage rolls

2.4.1. Mechanisms of Droplet Removal

Droplets are removed from a vapor stream through a series of three stages: collision & adherence to a target, coalescence into larger

droplets, and drainage from the impingement element. Knowing the size distributions as explained above is important because empirical

evidence shows that the target size - important in the first step of removal - must be in the order of magnitude as the particles to be removed.

These steps are shown schematically in Figure 3 for mist elimination using a wire mesh mist elimination. (Industries, 2016)

Figure 6: Droplet capture in a mesh pad


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2.4.2. Design Equation

To determine mist eliminator cross-sectional area (and hence vessel size) and predict performance in terms of removal efficiency, the

optimum design gas velocity is determined first. The Souders-Brown equation is used to determine this velocity based on the physical

properties of the liquid droplets and carrying vapor:

𝑉𝑑 = 𝑘(𝜌𝐿 − 𝜌𝐺/𝜌𝐺)1/2 ................................................................................................................................................. (2-10)

Where:

Vd : design gas velocity (ft/sec)

k : Capacity Factor (ft/sec)

𝜌𝐿 : Liquid density

𝜌𝐺 : Vapor Density

3. METODOLOGI

The author collects data for thesis preparation materials using the following methods:

3.1. Data collection

The data taken are field data Well Pad "X". The following are data and data collection methods needed to carry out this research:

a. Pipe dimensions, data taken by direct measurement in the field using a field meter and a reference from the company, namely

piping dimension Well Pad "X"

b. Mass flow, data taken from company references in the form of a flow test result report (Tracer Flow Test) which consists of

average total flow, steam production separator, and production separator brine.

c. Pressure and fluid temperature, data taken from company references in the form of a flow test result report (Tracer Flow Test).

d. Steam fraction, data is taken from company references in the form of a flow test result report (Tracer Flow Test).

3.2. Data Analysis Process

The data analysis process uses the Hysys 8.8 software process in order to simulate the Well Pad "X" fluid flow. After simulating using

Hysys 8.8, the results of the hydraulic analysis are steam fraction, temperature, pressure, mass flow, molar flow, enthalpy, and steam

properties (density and viscosity). The results of the analysis hydraulics are then used to recalculate surface facilities well pad "X. The

surface facilities re-planning process will be displayed in the form of a flow chart which can be seen in Figure 7.

Start

Input data

Dimention of pipe, mass flow, pressure, temperature, and

steam fraction

Hysys 8.8

Output

Dteam fraction, temperature, pressure, mass flow, molar flow, enthalpy,

and steam properties (density and viscosity)

Re-design

Separator and Demister Pad

Result

Develoment to field

Finish

Figure 7: Flowchart for Determining Re-Designing Separator with Demister Pad use Hysys


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4. DISCUSSION

4.1. Hydraulic, Heat and Material Balance Analysis

4.1.1. Planning Data and Assumptions

The design data used for hydraulic analysis are as follows:

➢ Operational Well Pad “X” data (2019)

Table 2: Operational Well Pad “X” data

Variable WELL “X”

Temperature (°C) 213,7

Pressure (barg) 19,5

Enthalpy (kJ/kg) 1.325

Total Flow Rate (t/h) 86,24

Dryness (%) 93,6

The pipe lengths and fittings for hydraulic analysis are based on the Well Pad “X” Piping Layout Drawing document and direct field

measurements. The assumptions used are as follows.

• Fitting of multi-phase pipe = 1 S-Bend, 3 Elbow 90o, 2 Valve, and 1 Tee

• Multi-phase Pipe length = 87,104 m

• Fitting of steam pipe = 3 Elbow 45o, 1 Tee and 1 Valve

• Steam pipe length = 70,3 m

• Fitting of brine pipe = 3 Elbow 45o and 4 Valve

• Brine pipe length = 136,2 m

• Safety factor = 50 %

4.1.2. Simulation Analysis Results

a. Process Flow Diagram Hysys Simulation

After collecting data in the field as shown in Table 2, the next step is to simulate a process using Hysys 8.8 to obtain data in the form of

flow rate, temperature, pressure, density, viscosity, and enthalpy. The flow process in Well Pad "X" starts from the production well, two-

phase pipe, separator, single-phase (steam) pipe, single-phase brine pipe, Silencer, weirbox, and cooling pond. The results of the process

flow diagram Well Pad “X” simulated in Hysys 8.8 can be seen in Figure 8.

b. Heat and Material Balance

After the simulation using Hysys 8.8, the results of the hydraulic analysis are obtained in the form of steam fraction, temperature, pressure,

mass flow, molar flow, enthalpy, and other steam properties which can be seen in Table 3. From these data, the calculation of design

surfaces, facilities will be carried out.

Figure 8: Process Flow Diagram Well Pad "X" (Hysys 8.8 Simulator Result)


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Table 3: HMB Process Flow Diagram Well Pad “X”

4.2. Separator Sizing Well Pad “X”

4.2.1. Calculation Data

The design data needed for the calculation of separator sizing includes operating data, fluid types, fluid properties and design criteria.

Operating data and fluid properties were obtained from the simulation results of Hysys 8.8 in the results of the previous hydraulic analysis.

a. Operation Data

Operation data were obtained from Hysys 8.8 simulation of Well Pad “X” hydraulic analysis. The operational data can be seen in Table 4

below:

Table 4: Fluid conditions flowing into the production separator Well Pad "X"

Variabel Unit Separator

Separation Pressure Barg 13.38

Separation Temperature oC 196.3

Flowrate Fluida t/h 126.8

Vapour Fraction 0.9398

b. Fluid Properties Data

The data on the properties of the fluid entering the separator is obtained from the Hysys simulation in hydraulic analysis. The data on the

properties of these fluids are as follows.

Table 5: Well Pad "X" Fluid Properties Data

Variabel Unit Separator

Density Steam Lb/cuft 0.4555

Density Brine Lb/cuft 54.23

Density Mixture Lb/cuft 0.4844

Viscosity Steam cP 0.0155

Stream No. Unit 1 2 3 4 5 6

Description

Fluida 2 fase from

WELL PAD “X”

to P-100-

Multiphase

Fluida 2 fase

from P-100-

Multiphase to

throttle valve

Fluida 2 fase

from throttle

valve to P-

101-

Multiphase

Fluida 2 fase

from P-

101-

Multiphase to

Separator

Steam from

SEPARATOR

to P-102-

Steam

Steam

from P-

102-

Steam

Steam Fraction 0.9360 0.9357 0.9415 0.9398 1.00 1.00

Temperature C 213.7 213.4 198.9 196.3 195.8 194.1

Pressure barg 19.5 17.92 14.9 13.38 13.18 12.71

Mass Flow tonne/h 126.8 126.8 126.8 126.8 119.1 118.9

Molar Flow kgmole/h 7,036 7,036 7,036 7,036 6,612 6,598

Enthalpy kJ/kg 1,325 1,325 1,325 1,325 1,314 1,314

Stream No. Unit 7 8 9 10 11 12

Description

Brine from

SEPARATOR

to Throttle

Valve_2

Brine from

Throttle

Valve_2 toP-

103-Brine

Brine from P-

103-Brine to

SILENCER

The residual

steam heads for

the atmosphere

Brine from

SILENCER to

Weir Box

Cool Brine

to Cooling

Ponds

Steam Fraction 0.00 0.9672 1.00 1.00 0.00 0.00

Temperature C 196.3 181.6 177.9 100.00 100.00 40.00

Pressure barg 13.38 9.379 9.374 0.00 0.00 0.00

Mass Flow tonne/h 7.636 7.386 7.636 1.133 6.503 6.503

Molar Flow kgmole/h 423.9 410 423.9 62.90 361 361

Enthalpy kJ/kg 1,509 1,509 769.8 1,325 1,551 1,576


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4.2.2. Determination of the Type of Separator

The recommended separator for Well Pad "X" in the Dieng Geothermal area is a vertical steam-water separator using a demister pad.

a. Assumption

The assumptions used for the calculation of the Separator are as follows:

• Safety factor = 50%

• Max Pressure Drop = 0,2 Bar (20 kPa)

• Residence Time = 10 Minute

b. The calculation results

The sizing separator calculation process is shown in Appendix-1. While the calculation results of the separator from the P-101-Multiphase

Well Pad "X" pipe are shown in Table 6 below:

Table 6: Calculation Result for Well Pad "X"

Information Unit V-182-2

Height

Height from demister pad to top steam line vessel H4 m 0.44

Height from inlet nozzle to demister pad H3 m 1.22

The height from the liquid level limit to the inlet

nozzle feed H2 m 1.75

The height of the HLL liquid from the bottom

steam line vessel H1 m 0.97

Demister Pad

Thick demister pad Hdp m 0.75

Demister pad diameter Ddp m 2.2

Nozzle

Diameter nozzle inlet (feed) Dfeed inch 18

Diameter nozzle outlet (steam) Dsteam inch 16

Diameter nozzle outet (brine) Dbrine inch 6

Dimensions of Separator

Height (H4+Hdp+H3+H2+H1+Dfeed) H m 4.8

Diameter separator D m 2.5

Height - Diameter ratio H/D - 1.92


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Figure 9: Well Pad Separator Dimensions "X"

c. Explanation

Based on the results of separator calculations in Table 6, it is found that the separator dimensions that meet the design criteria based on the

limitations of API 12J are as follows:

Table 7: Selection of Well Pad Separator "X"

Separator Unit Well Pad

“X”

Diameter, D m 2,5

Hight, H m 4,8

Ratio H/D m 1,92

Based on the table. The 7 dimensions of the new separator are very different from the previous one. In the previous design the pipe diameter

was about 1.5 m while the result of the re-design was 2.5 m. This difference is due to the fact that before the re-design the 2-phase fluid that

entered the separator was less, namely around 40 tons / hour with a steam fraction of 60%, so that the steam to be produced was around 24

tons / hour and brine was 16 tons / hour. Meanwhile, currently the 2-phase fluid entering the separator is 84.5 tons / hour with a steam

fraction of 93.6%, so that the steam produced is 79.1 tons / hour and brine is 5.4 tons / hour. The amount of fluid flowed by the well to this

separator will affect the dimensions of the separator used. Large steam production will require a larger diameter of the separator for optimal

separation and less pressure loss. Meanwhile, the height of the separator is influenced by the brine which is separated. If the separated brine

has a large volume, a high separator dimension is required to accommodate the brine. Meanwhile, the redesigned separator is not very high,

this is because the brine is less separated than before.

4.2.3. Separator Efficiency Analysis

Geothermal fluid produced from Well Pad "X" is flowed using a two-phase flow pipe (steam and brine) of 126.8 tons / hour. The fluid will

flow to the separator to find out between steam and brine. From the results of the separation of steam production of 119.1 tons / hour and

steam production of 7.6 tons / hour. So as to get the vapor fraction value as follows:

𝑋 =𝑀𝑠𝑡𝑒𝑎𝑚

𝑀𝑠𝑡𝑒𝑎𝑚 + 𝑀𝑏𝑟𝑖𝑛𝑒


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=119.1

119.1 + 7.6

= 94.0016 %

From the results of the above calculations it is assumed that the separator has not used a demister pad so that the efficiency of the separator

is 94.0016%.

To separate steam and brine even better, a demister pad was installed. In this study, the demister pad used was Mesh Style with metal mesh

material. This efficiency is the percent of all incoming droplets of the given diameter which will be captured rather than passing through

the mist eliminator. The percentage will be higher for larger droplets and lower for smaller.

𝐸𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦 % = 100 − (100/𝐸𝑋𝑃(𝐸. 𝑆𝑂)

Dimana:

S0 = Corrected Pad Specific Surface Area

E = Impaction efficiency fraction

The following is the calculation of the efficiency of the Mesh style demister pad.

➢ Mesh style 4CA

The Impaction efficiency fraction (E) value is 0.15 (Figure 10) with a K value of 0.35 (Standard Souders-Brown Coefficients (k factors)

for mesh and Plate-Pak ™ Unit) is:

The Corrected Pad Specific Surface Area (SO) value is 85 ft2 / ft3 (The Engineered Mist Eliminator). So that the efficiency demister pad is

obtained:

𝐸𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦 % = 100 − (100/𝐸𝑋𝑃(0.35.85)

= 100 − 0.0003

= 99.9997%

From the results above, the separator using the 4CA Mesh Style demister pad will have an efficiency of 99.9997%, so that it can separate

steam and brine even better. The results of calculation of steam and brine production using 4CA Mesh Style demister pad compared to

using standards are shown in the table 8.

Table 8: Comparison of steam production between separator and

demister pad Mesh Style 4CA and Standard Separator

Efficiency, % Steam,

ton/hour

Carry Out Condensate, ton/hour

Separator with demister pad

Mesh Style 4CA

99.9997% 119.0996 0.000357

Standard Separator 99% 117.9090 1.191000

Table 8 shows that the steam production using 4CA Mesh Style demister pad is better than the standard separator, this can be seen from the

Carry Out Condensate demister pad Mesh Style 4CA value which is smaller than the standard, which is 1.191000 tons / hour. Carry Out

Condensate is the condensate which is still followed into the one-phase steam flow pipe after it is from the separator. The smaller the value

Figure 10:Determining Impaction Efficiency Fraction E Using Intertial Parameter K



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of the Carry Out Condensate, the drier and nicer the steam will be. From the results above, the separator using the 4CA Mesh Style demister

pad will have an efficiency of 99.9997%, so that it can separate steam and brine even better. The results of calculation of steam and brine

production using 4CA Mesh Style demister pad compared to using standards are shown in the table.

5. ACKNOWLEDGEMENT

The authors would like to sincerely acknowledge all people who have supported us in the writing of this paper

6. CONCLUTION

The following are the conclusions of the study as follows:

• Production of Well Pad "X" is 84.5 tons / hour with a steam fraction of 93.6% so that steam production is 79.1 tons / hour and brine is

5.4 tons / hour with a pressure of 19.5 bar and temperature. of 213.5 ºC.

• Hysis 8.8 simulator is very useful for knowing steam properties that are difficult to obtain directly in the field and makes it easier to

find out the important parameters in the pipeline on Well Pad "X"

• The results of the re-design of the separator dimensions are 2.5 m (diameter) and 4.8 m (height).

• Demister pad re-design results are 0.75 m (Thick demister pad) and 2.2 m (Demister pad diameter).

• Demister pad used for this separator is Demister Pad Mesh Style 4CA with an efficiency of 99.9997%, so that steam production is

119.0996 tons / hour and carry out condensate is 0.000357 tons / hour.

• From the comparison of steam production and carry out condensate Separator with Demister Pad Mesh Style 4CA is more efficient

than standard separator because the value of the carry out condensate is smaller.

7. REFERENCES

12J, A. (1989). Specification for Oil and Gas Separator 7th Edition. Washington DC.

Ashat, A. (2019). Numerical Simulation Udate of Dieng Geothermal Field, Central Java, Indonesia. Proceedings 41st New Zealand

Geothermal Workshop.

ASME VIII. (2007). Construction of Pressure Vessel. USA: ASME.

Code, A. B. (2013). ASME VIII Rules and Contruction of Pressure Vessel. New York: The American Society of Mechanical Engineers.

DiPippo, R. (2008). Geothermal Power Plants. Oxford, UK: Elsevier.

Frank L. Evans, J. (1980). Equipment Design Handbook for Refeneries and Chemical Plants Second Editon. Houston, Texas, United States:

Gulf Publishing Company.

Industries, A. (2016). The Engineered Mist Eliminator. Houston, Texas, USA: ACS.

Nazif, Havidh (2019). Desain Pipa dan Separator. Dirjen EBTKE. Jakarta

Purwono, A. N. (2010). Compa and Selection of A Steam Gethering System in Ulubelu Geothermal Project, Sumatera, Indonesia.

Reykjavik: Geothermal Training Program. Orkustofnun, Greensasvegur 9. Reports 2010. Number 26 is-108.

Saptadji, N. (2018). Teknik Geotermal. Bandung: ITB Press.


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APPENDIX-1: SEPARATOR SIZING CALCULATION

1. Calculating the K Factor

= 𝑓𝑙𝑜𝑤𝑟𝑎𝑡𝑒 𝑏𝑟𝑖𝑛𝑒

𝑓𝑙𝑜𝑤 𝑠𝑡𝑒𝑎𝑚 𝑥 √

𝜌 𝑠𝑡𝑒𝑎𝑚

𝜌 𝑏𝑟𝑖𝑛𝑒

= 4,68

73,09 𝑥 √

0,4555

54,2300

= 0,0059

Kv = 0,41

2. Calculating the Maximum Vapor Speed (Umax)

(𝑢𝑣)𝑚𝑎𝑥 = 𝐾𝑣 √(𝜌1 − 𝜌2)/𝜌𝑣

= 0,41 √(54,2300 − 0,4555)/0,4555

= 4,45 𝑓𝑡/𝑠

3. Calculating the Minimum Area

𝐴𝑚𝑖𝑛 = 𝑄𝑣

𝑈𝑚𝑎𝑥

= 160,4596

4,45

= 36,02 𝑓𝑡2

4. Calculating Minimum Diameter

𝐷 min = [𝐴 𝑀𝐼𝑁

𝜋 / 4]

0.5

= [36,02

3,14 / 4]

0.5

= 6,77 𝑓𝑡

= 2,06 𝑚

D min Chosen = 8,13 ft

= 2,5 m

5. Checking Value Dmin ----> Umax

𝐴𝑚𝑖𝑛 = 𝜋 𝐷𝑚𝑖𝑛2

4

= 3,14 𝑥 6,772

4

= 36,02 𝑓𝑡2

𝑈𝑚𝑎𝑥 = 𝑓𝑙𝑜𝑤 𝑟𝑎𝑡𝑒 𝑠𝑡𝑒𝑎𝑚

𝐴 𝑚𝑖𝑛

= 160,4596

36,02

= 4,45 𝑓𝑡/𝑠

6. Calculating the Vapor-Liquid Inlet Nozzle

(𝑢𝑚𝑎𝑥)𝑛𝑜𝑧𝑧𝑙𝑒 = 100 √𝜌𝑚𝑖𝑥

= 100 √0,4844



13

= 69,60 𝑓𝑡/𝑠

(𝑢𝑚𝑖𝑛)𝑛𝑜𝑧𝑧𝑙𝑒 = 60 √𝜌𝑚𝑖𝑥

= 60 √0,4844

= 41,76 𝑓𝑡/𝑠

𝐴𝑚𝑖𝑛 =𝑓𝑙𝑜𝑤 𝑟𝑎𝑡𝑒 𝑖𝑛𝑙𝑒𝑡 𝑡𝑜𝑡𝑎𝑙

(𝑢𝑚𝑎𝑥)𝑛𝑜𝑧𝑧𝑙𝑒

=160,55

69,60

= 2,31 𝑓𝑡2

𝐷𝑚𝑖𝑛 = √𝐴𝑚𝑖𝑛 𝑥 4

3,14

= √2,31 𝑥 4

3,14

= 1,71 𝑓𝑡

= 20,57 𝑖𝑛

= 24 𝑖𝑛 (based on Pipe-101)

7. Calculating Liquid Volume

Residence Time = 10 minute

= 600 second

V = 0,0862 x 600

= 51,74982 cuft

8. Calculating the Height of Liquid (HI) and Vapor (Hv)

𝐻𝑙 𝐿𝑖𝑞 𝑀𝑎𝑥 = 𝑉 (4/𝜋𝐷2)

=51,74982 𝑥 4

3,14 𝑥 (6,772)

= 1,44 𝑓𝑡

= 17,24 𝑓𝑡

= 0,44 𝑚𝑚

𝐻𝑣 = 36 + (0,5 𝑥 𝐷𝑚𝑖𝑛)

= 36 + (0,5 𝑥 24)

= 48,00 𝑖𝑛

= 4 𝑓𝑡

= 48,00 𝑖𝑛

= 4,00 𝑓𝑡

= 1,22 𝑚

𝐻𝑓𝑒𝑒𝑑 𝑛𝑜𝑧𝑧𝑙𝑒 𝑡𝑜 𝑚𝑎𝑥. 𝑙𝑒𝑣𝑒𝑙 = 12 + 0,5 𝑥 𝐷𝑚𝑖𝑛

= 12 + 0,5 𝑥 24

= 2 𝑓𝑡

𝐻𝐼 = 𝐻 𝐿𝑖𝑞 𝑀𝑎𝑥 + 𝐻𝑓𝑒𝑒𝑑 𝑛𝑜𝑧𝑧𝑙𝑒 𝑡𝑜 𝑚𝑎𝑥. 𝑙𝑒𝑣𝑒𝑙

= 1,44 + 2

= 3,44𝑓𝑡

= 1,05 𝑚

𝐻𝑡𝑜𝑡𝑎𝑙 = 𝐻𝐼 + 𝐻𝑣 + (𝑇2

12) + 𝐶𝑚 + 𝐷𝑚𝑖𝑛

= 3,44 + 4 + (6

12) + 5,37 + (

24

12)

= 15,31 𝑓𝑡

= 4,67 𝑚

9. Checking Geometry

𝐻𝑙 + 𝐻𝑣

𝐷=

15,31

8,13

= 1,88 (Received)


14

10. Determine the Demister Size

K = 0,35

Velocity = 3,31 fps

𝐴 = 𝑓𝑙𝑜𝑤𝑟𝑎𝑡𝑒 𝑠𝑡𝑒𝑎𝑚

𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦

= 160,4596

3,80

= 42,19 𝑓𝑡2

𝑉𝑖𝑠𝑐𝑜𝑐𝑖𝑡𝑦 = 0,015 𝑐𝑃

= 1,00792𝐸 − 05 𝑙𝑏/𝑓𝑡. 𝑠

𝑑 = 0,011 𝑖𝑛𝑐ℎ

= 0,000916667 𝑖𝑛𝑐ℎ

𝐷 𝑑𝑒𝑚𝑖𝑠𝑡𝑒𝑟 = √𝐴 𝑥 4

3,14

= √42,19 𝑥 4

3,14

= 7,3𝑓𝑡

= 2,2 𝑚

𝐾 = (( 𝜌 𝑏𝑟𝑖𝑛𝑒 − 𝜌 𝑠𝑡𝑒𝑎𝑚) 𝑥 𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦 𝑥 (𝑑2 ) / (9 𝑥 𝑣𝑖𝑠𝑐𝑜𝑐𝑖𝑡𝑦 𝑥 𝐷 𝑑𝑒𝑚𝑖𝑠𝑡𝑒𝑟) = (( 54,2300 − 0,4555) 𝑥 3,80 𝑥 (0,00091672 ) / (9 𝑥 1,00792𝐸 − 05 𝑥 7,3) = 0,26

S = 85 ft2/ft3

E = 0,15

T1 = 4 inch

= 1,2 m

T2 = 6 inch

= 0,2 m

gc = 32,27 lb/ft2.s

Mesh void fraction = 98,2

SO1 = S x 1/3,14 x (T1/12) x 0,67

= 85 x 1/3,14 x (4/12) x 0,67

= 6,0456

SO2 = S x 1/3,14 x (T1/12) x 0,67

= 85 x 1/3,14 x (6/12) x 0,67

= 9,06585

Eff 1 = 100-(100/EXP(SO1 x E)

= 100-(100/EXP(6,0456 x 0,15)

= 59,6205

Eff 2 = 100-(100/EXP(SO2 x E)

= 100-(100/EXP(9,0685x 0,15)

= 99,9997

Di Nozzle Out = 17,94 inch

= 1,49 ft (piping size)

R Nozzle Out = Di Nozzle Out / 2

= 17,49 / 2

= 0,75 inch

𝑋 = (

𝐷𝑚𝑖𝑛 𝐶ℎ𝑜𝑠𝑒𝑛2

− 𝑅 𝑁𝑜𝑧𝑧𝑙𝑒 𝑂𝑢𝑡)

𝐶𝑜𝑠 45°

= (

8,132

− 0,75)

𝐶𝑜𝑠 45°

= 6,31 𝐹𝑇

𝐶𝑚 = 𝑆𝑖𝑛 45° 𝑥 𝑋

= 𝑆𝑖𝑛 45° 𝑥 6,31

= 5,37 𝑓𝑡

∆𝑃𝑑𝑟𝑦 = 0,4 𝑉𝑑2 𝜌𝐺𝑆𝑇/𝑔𝑐 𝜀 𝜌𝑤

= 0,4 3,8 𝑥 (0,0009167)2 𝑥 0,4555 𝑥 85 𝑥 385,40/54,23 𝑥 98,2 𝑥 32,27

= 1,1145121 𝑖𝑛𝐻2𝑂

= 0,0402339 𝑝𝑠𝑖



15

11. Determine the Minimum Wall / Shell Thickness

Poperasi = 208,70 psig

Pdesain = Poperasi + 25

= 208,70 + 25

= 233,70 psig

Toperasi = 385,40 degF

Tdesain = Tdesain + 50

= 385,40 + 50

= 435,40 degF

E = 0,80

D(Dmin)= 6,77 ft

R = D/2

= 6,77 / 2

= 3,39 ft

S = 20.000 psi

C = 0,125 inch

𝑡𝑚𝑖𝑛 =

(𝑆 𝐸𝑡

𝑅𝑗 + 0,6 𝑡) 𝑅𝑖

𝑆𝐸 − 0,6 𝑃

𝑃 = 𝑆 𝐸𝑡

𝑅𝑗 + 0,6 𝑡

𝑡 = [(𝑃𝑑𝑒𝑠𝑎𝑖𝑛 𝑥 (𝑅 𝑥 12)

(𝑆 𝑥 𝐸) − (0,6 𝑥 𝑃𝑑𝑒𝑠𝑎𝑖𝑛)) + 𝐶]

= [(233,70 𝑥 (3,39 𝑥 12)

(20.000 𝑥 0,80) − (0,6 𝑥 233,70)) + 0,125]

= 0,7239 𝑖𝑛𝑐ℎ

= 0,75 𝑖𝑛𝑐ℎ

12. Determine the Minimum Heads Thickness

The head used is ellipsoidal

Poperasi = 208,70 psig

Pdesain = Poperasi + 25

= 208,70 + 25

= 233,70 psig

Toperasi = 385,40 degF

Tdesain = Tdesain + 50

= 385,40 + 50

= 435,40 degF

E = 0,80

D(Dmin)= 6,77 ft

S = 20.000 psi

C = 0125 inch

𝑡𝑚𝑖𝑛 =

(𝑆 𝐸𝑡

𝑅𝑗 + 0. ,6 𝑡) 𝑅𝑖

𝑆𝐸 − 0,6 𝑃

𝑃 = 𝑆 𝐸𝑡

𝑅𝑗 + 0,6 𝑡

𝑡 = [(𝑃𝑑𝑒𝑠𝑎𝑖𝑛 𝑥 (𝑅 𝑥 12)

(𝑆 𝑥 𝐸) − (0,6 𝑥 𝑃𝑑𝑒𝑠𝑎𝑖𝑛)) + 𝐶]

= [(233,70 𝑥 (3,39 𝑥 12)

(2 𝑥 20.000 𝑥 0,80) − (0,2 𝑥 233,70)) + 0,125]

= 0,7195 𝑖𝑛𝑐ℎ

= 0,75 𝑖𝑛

redesign of well pad "x" geothermal separator with demister ...

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