Improving Efficiency of Sealing Water Systems

8/6/2019 Improving Efficiency of Sealing Water Systems

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Seal Water Control SystemProposal

1

TECHNICAL PROPOSAL

Seal Water Control Systems

PT TJIWI KIMIA - Mojokerto

A 13.08.08 First Issue First Issue

ISSUE REV. DATE: DD/MM/YYSTATUS DESCRIPTION

This Document is confidential. The copyright is vested in John Crane SingaporePte Ltd. All rights reserved. Neither the whole nor only part of this document maybe disclosed to any third party or reproduced, stored in any retrieval system ortransmitted in any form or by any means (electronic, reprographic, recording orotherwise) without the prior written consent of the copyright owner.

TITLE:

Improving efficiency of Sealing Water System

DOCUMENT NO.:

PT. John Crane IndonesiaCilandak Commercial Estate #401A

Jakarta 12560

ISSUED BY: Rudy Wijaya, PT. John Crane Indonesia tel: +62 21 789 0068 fax: +62 21 789 0848E-mail: [email protected]


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1. CONTENTS

1. Contents

2. Operating Conditions Overview

3. Objective

4. Smart Flow Feature

5. Cost Saving Analysis

6. Comments


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2. Operating conditions Overview

Equipment Mfr : Goulds 3196MTPump material : Titanium

Service : Brine PumpTemperature : + 50 CDisch. Press : 61 PsiG

Suct. Pres : 10-15 PsiG

Mech. Seal : John Crane DoubleSeal size 1.3/4 T8-1-DBLBarrier Liquid : Demin Water

Brine Pump at Chemical Plant

The process liquid being pumped is Brine, a chemical liquid which is very corrosive and should beavoided for contacting directly to human or environment. There are 2 units pumps that some timerunning together but most of the time only 1 unit pump running and the other is stand by. To avoid theprocess liquid leak to the atmospheric side a double back to back mechanical seal design is installed.

The operation of this seal design is required external liquid (other than process liquid) that will beused as barrier liquid at pressure 1 bar higher than stuffing box pressure.

The stuffing box pressure (seal pressure) is calculated as follows :

S/box pressure : suction pressure + (0.3 x differential pressure)(in PsiG) : 15 + (0.3 x (61 15))

: 15 + (0.3 x 46): 28

*) we assume the suction pressure is 15-20 PsiG

Base on the above calculation the ideal pressure of barrier fluid should be around 35 45 PsiG at all

the time, note : higher pressure is allowed to ensure the positive pressure in the stuffing box.

Double Back to Back Seal


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Demin Water

IN

Demin Water

Out

CURRENT

OPERATION

50 PsiG

2 ltrs/9 sec

Demin Water

IN

Demin Water

Out

CURRENT

OPERATION

50 PsiG

2 ltrs/9 sec

In the operation of double back to back seal, small amount of barrier seal will leak to process sidewhen the inboard seal is damage and they leak to atmospheric side when the outboard seal is

damage, this is because of the pressure of the barrier seal is higher than s/box pressure (pressurebehind the impeller). Any barrier fluid pressure drop below s/box pressure (28 psiG) will lead theprocess liquid (brine) entering the seal cavity and easily damaging the mechanical seal.

Base on site inspection that taken place on 6 August we discovered that Demin Water is injected tomechanical seal through the inlet port at pressure of 50 Psig there is a P.I (Pressure Indicator) tomeasure the pressure of Demin Water. The function of Demin Water is to isolate the process liquid tonot entering the seal cavity, and also to cooling/lubricating the seal faces of mechanical seal.

We discovered that Demin Water was pipelined out from the mechanical seal to the water drainagenear by the pump. The flow rate of Demin water was measured at 2 litres per 9 seconds per pump(pressure at 50 PsiG). The flow and pressure of the Demin water prior to mechanical seal were

controlled manually using valve regulator, P.I. is available but there is no F.I (Flow Indicator) tomeasure the flow rate.

The actual flow rate of Demin Water in these pumps is 1liter per 4.5 second or equivalent to 19.2M/day. The pressure is maintained at 50PsiG, it should be 10-15 Psi higher than stuffing boxpressure.

3. OBJECTIVE

John Crane customer, PT. Tjiwi Kimia is looking for solution to reduce Demin Water Consumptionwhich is currently very high i.e. 19.2 M/day (7008 M/year). Base on empiric cost of Demin Waterthat usually used in European country which is estimated at Eu 0.5/ M, then the cost of DeminWater for this pump is around Eu 3504/pump/year.

John Crane Safematic Finland is one of the leading company who supply technology to Pulp andPaper in the world. We are producing mechanical seal and sealing water device and help customerenhancing the plant reliability and reduce unnecessary operating cost.

One of the John Crane technology in Sealing Water equipment is SmartFlow that designated toreduce sealing water consumption at very minimum level without interrupting the reliability of the


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equipment/pump. Field experience shows average water savings of over 95% achieved comparedwith flow meter systems

4. SMART FLOW FEATURE

SmartFlow is an Intelligent Seal Water Control System which considerably reduces water usage andhence operating costs.

The SmartFlow is available in two forms

a Universal design suitable for all pumps

an Integrated version designed for use with JC Safematic JCS2 seals

The Universal SmartFlow has water circulation to transfer heat to the operating valve while theSmartFlow IG is integrated to (and operates inside) the seal so does not need circulation.

Memory shape alloy springThe spring is manufactured from a Nickel Titanium alloy. NiTi is a temperature-activated material, whencool it is pliable and can be easily deformed to any shape. If the material is heated to its activationtemperature it "remembers" its original programmed shape and returns to it - applying force againstanything it its way. i.e. it changes from a pliable piece of material to a spring.

Note, in the Universal SmartFlow seal water circulation is necessary for memory metal activation

FilterThe Universal SmartFlow includes a filter to ensure failure-less equipment operation, note this is for valveprotection only and is not suitable for line filtration. The filter has to be checked and cleaned on regularbasis in order to prevent clogging. Cleaning frequency is dependant on the quality of seal water used.

Safety valveA safety valve based on seal water temperature is incorporated in the equipment. This is not shown on theabove diagram (Universal SmartFlow) but is normally located at the outlet from the gland plate (inlet to theSmartFlow). The safety valve will open should such operational failure occur on the equipment causingthe seal water temperature to exceed 90 C (195 F). In the Integrated SmartFlow a safety valve is builtinto the unit.


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SmartFlow operation is based on a heat-activated, shape memory, alloy spring that mechanicallyopens and closes the flow channel. The system automatically adjusts to new operating conditions, i.e.alternating pressure and temperature.

The Universal and Integrated SmartFlow operate in very similar ways, the main differences being

during cool operation, the Universal SmartFlow circulates seal water in a closed loop whilethe Integrated SmartFlow prevents seal water flow

the Integrated SmartFlow has a safety valve built in to its construction, the Universal

SmartFlow uses a separate safety valve

When the barrier/ buffer fluid is cold the spring is in its pliable state and the flow valve in theSmartFlow remains closed. This causes the fluid to be recirculated through the stuffing box. (Note, inthe case of the integrated SmartFlow there is no flow).

When the temperature increases to 60 C (140 F) the alloy changes and transmits axial force like anormal spring. This force opens the flow valve allowing hot seal water to flow to drain (or collectionpoint) and the system is topped-up by cold water. This cools the circulation flow and returns thespring to its pliable state, the flow valve then closes and the cycle repeats.

The equipment causes a pressure loss when it opens, the extent of the loss depends on the sealwater pressure. At maximum pressure the loss is approx. 1.5 bar (21 psi). It is thus recommendedthat seal water pressure is set 2 bar (30 psi) above sealed liquid pressure. A separate safety valve,based on seal water temperature, is normally located at the outlet from the gland plate (inlet to theSmartFlow).


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The safety valve is normally held closed by a retaining ring made from memory shape alloy. Shouldan operational upset occur, causing seal water temperature to reach 90 C (195 F) the ring materialwill activate causing it to expand out of its groove. This allows the spring to open the valve andrelease hot water.

Note, once the SmartFlow safety valve has operated it can be re-set and does not requirereplacement.

5. COST SAVING ANALYSIS

The primary use of SmartFlow is for controlling seal water flow in double-balanced mechanical seals.Customers are demanding reduced seal water consumption which can give them very significantsavings in

water supply (incl. lower filtration costs)

waste water disposal

compliance with environmental aspects / standards

SmartFlow delivers those savings with reduction in seal water usage of typically 95% compared toflow meter regulated flow-through systems (see table below). The average payback period forSmartFlow is less than 15 months.

Note. Water consumption is affected by product temperature, rotation speed, seal water temperature(from line), surrounding temperature and seal water pressure.

Estimate cost of current operation (per pump) :Water Usage : 7008 M/Year

Cost of Water : 7008 M x 0.5 = 3504


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Expected Water Saving by 95% (base on field experience)Saving : 7008 M x 0.95 = 6.657 M

In Euro : 6.657 M x 0.5 = 3328/pump

Pay Back Analysis :

Cost of Smart Flow : 1066 per unitCost of Water : 3504 per pump/year

Pay Back (month) : )12

3504(1066Eu

Eu

: 3.65 months

6. COMMENTS

Return of investment can be achieved in 3.65 months, most of management will continue theBusiness Plan if the R.O.I. less than 24 months.


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Cost Saving Analysis :

Case Study Tjiwi Kimia P & Paper


FACT FINDINGS) :

Demin Water Press : 50 PsiG (PI)

No Flow Indicator

Actual Flow : 2ltr/9 sec (13.3 ltr/mnt)

(Note : using glass measurement)

ACTUAL COST OF OPERATIONS :

Demin Water : 13.3 ltr/mnt X 60 X 24 X365 days

6.990.480 ltr/yror 6.990M/Yr

Cost/Price : Rp. 6.000/M

Total Cost : Rp. 41.940.000,- perpump


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One of the John Crane technology in Sealing Water equipment is SmartFlow that designatedto reduce sealing water consumption at very minimum level without interrupting the reliability of

the equipment/pump.

Field experience shows average water savings of over 95% achieved compared withflow meter systems


The Universal and Integrated SmartFlow operate in very similar ways, the main differences being : during cool operation, the Universal SmartFlow circulates seal water in a closed loop while the

Integrated SmartFlow prevents seal water flow. the Integrated SmartFlow has a safety valve built in to its construction, the Universal SmartFlow

uses a separate safety valve


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COST SAVING ANALYSIS :

The use of Safe Unit will reduce Demin water consumption from13.3 ltr/mnt to 4 ltr/mnt (or 6.990 M/year to 2.102 M/year)

Cost of Demin Water reduce from : Rp. 41.940.000,- per year to Rp.12.614.000 (cost saving Rp. 29.325.600 per year)

The use of Smart Flow will reduce 90% of Demin WaterConsumption by 90% from Rp.12.614.000,- to becomeRp.1.261.400,- (Cost Saving Rp. 11.352.600,- per year)

PAY BACK ANALYSIS :

Cost of Safe Unit + Cost of Smart Flow : Rp. 6.000.000,- + Rp.16.000.000,- = Rp. 22.000.000,-

Cost saving due to the use of Safe Unit + Smart Flow : Rp. 29.325.600,- +Rp. 11.352.600 = Rp. 40.678.200,- per year

Pay Back : Rp. 22.000.000/(Rp. 40.678.200,-/12) = 6.48 mths


Return of investment can be achieved in 6.48 months,most of management will continue the Business Plan

if the R.O.I. less than 24 months.


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Improving Efficiency of Sealing Water Systems