Train Lecture (Indrama,Indonesia)(2xCNDQ-10)(Rev1.0)2014!11!07

8/9/2019 Train Lecture (Indrama,Indonesia)(2xCNDQ-10)(Rev1.0)2014!11!07

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Technical Trainin

for Hydrogen generation by Water Electrolysis-CNDQ Series

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Copyright Announcement

This document is the property of the PURIFICATION EQUIPMENT

RESEARCH INSTITUTE OF CSIC, it must not be used, reproduced,

transmitted or disclosed to any other third-party without the prior

wr tten perm ss on oINSTITUTE OF CSIC.


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ContentPage 3

.

Chapter 2. auxiliary unitChapter 3. rectifying unit

.

Chapter 5. troubleshooting

Chapter 6. relative knowledge


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Chapter 1. Flow chat and component of H2 generation unit

Working principle

2H2O 2H

2 O

2

The purpose of H2 generation unit is to decompose H 2O into H2 and O2 by

electrolysis.So we need H2 generation unit, power , water, cooling water unit, instrument air ,

and so on.

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Rectifier

PDB/MCC PanelChapter 2. Flow chat and component of H2 generation unit

H2 generation unitCNDQ-10/1.5

H2 purification unitQCY-10/1.5

Automatic control panel

Close-loopcooling water PLC control panel

HMI DM water tankLye tank

Automatic control panel

Rectifier

Skidded type H2 generator I (Frame I)H2 generation unit

CNDQ-10/1.5H2 purification unit

QCY-10/1.5

Power supply415VAC, Triphase IA source0.5~0.7MPa N2 source0.6~2.0MPa DM water supply0.02m3/h CW supply0.35~0.45MPa ChemicalsKOH, V2O5


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DM water is exceedingly weak electrolyte, h + and Oh-ions concentration is low, when temperature

reaches 25 c, [H+]=1x10-7M;[OH-]=1x10-7M.

So the water almost is not conductive. So in water electrolysis, other strong electrolyte must be added

to enhance the conductivity.

Choosing electrolytes is very important, comprehensive factors including electrical conductivity, stability,

corrosion and econom should taken into consideration, Generall re uirements:

1) Conductivity is good

2) No decomposition under electrolyzing voltage

3) Under operating conditions ,electrolyte not escape with hydrogen and oxygen for venting,

4) No severely corrosion to electrolyzer,

, .

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Strong acid (H2SO4), alkali (such as NaOH, KOH) can meet the above requirements. Most salt often broken

down during electrolysis and can not be used. Among them, solution of sulfuric acid with high conductivity,

good stability, low price, gas separated easily, but the sulfuric acid products sulfuric acid and ozone in anode ,

, . ,

corrosion for nickel plated electrodes, generally used as the electrolyte in H2 generation unit by water

electrolysis.

KOHs electric conductivity is better than NaOH, but the price is higher, when the temperature is high, KOH

is more corrosive than NaOH to electrolyzer. In the past choose NaOH as electrolyte, but now the

electrolyzer structure and the material upgraded and it can prevent KOHs corrosion. In order to reduce

power consumption, we generally choose KOH.

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Water consumption

In normal condition, theoretically, water electrolysis produce 1m3 hydrogen and 0.5 m3 oxydrogen which

=. .

Hydrogen and oxygen take away some of the water vapor and mist, so the actual water consumption is more.

Quantity of moisture taken away by hydrogen and oxygen changes in the range of about 25 to 50 g / m 3 as

temperature and pressure varies.Moisture taken away by 1m3 hydrogen and 0.5m3 oxygen is 40~75 g/m3 in average , actual water

consumption is 845 ~880g,Generally, similar to that generated 1 m3 of hydrogen, water consumption of

1,000 g (1 liter)

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1. The operation temperature is about 90 , so do not touch electrolyzer when H2 unit is running

2. Do not put anything on electrolyzer, especially the metal

3. Every time operate H2 unit, you should take a record of cell voltage . Because if a cell is broken, the

cell voltage shall be higher. Normally, cell voltage is 2V if cell voltage is higher than 2.2V this

electrolyzer.

4. If the purity of O2 or H2 is getting lower, this means the membrane inside electrolyze is getting worse,

then you should consider the maintenace of electrolyzer.

5. The life of electrolyzer is about 10 years (asbestos) / 5 years (non- asbestos), at the condition of that the

quality of DM water is good.

6. As electrolyzer expand with heat and contact with cold, so only one side of electrolyzer need to be fixed,

.

7. Leakage problem.

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8. DM water. Guarantee the quality of DM water, or the performance of electrolyzer shall getting

worse.

9. If H2 unit stopped for long time, how to take care of electrolyzer Purge N2 into H2 unit, and

.

return lye back to lye tank, to prevent the reaction with CO2.

10. Replacement of electrolyzer. Confirm the positive and negative of electrolyzer, and confirm

the H2 pipe and O2 pipe, any mistake may lead to seriously accident.11. When H2 generated, you need to re-confirm the gas. You can read the date from gas analyzer,

and also you can check the gas by soap bubble.

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Page 12

Gas-lye treater

, ,

and drying, to meet requirements of product gas. CNDQ series hydrogen generation system by water

electrolysis adopts integrated design, which gathers electrolyzer, gas-lye processor and H2 dryers into one

frame, called frame one. Gas-lye processor composed of lye circulation system, H2 system, O2 system, H2

drying system, water(lye) supplementary system and cooling water system.


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Page 13

Flow Chat


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Page 14

Photos


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Page 15

Lye circulation systemH2 mixed with lye flows out from the outlet at H2 side of electrolyzer enters into H2 separator, O2 mixed

with lye flows out from the outlet at O2 side of electrolyzer enters into O2 separator, and is separated from

lye in separator, lye flows together in pipeline at lower part of separator and flows into lye filter, and

, .

H2&LYE O 2&LYE

DC POWER SUPPLYLYE OUTLET

LYE INLET


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Lye preparation loop

From the loo as seen here this loo alon with l e tank in

frame ) forms a circulation loop, when preparing lye,

open the circulation could realize heat dispatching, as well as

preventing lye from crystallizing to cause block at tank

bottom and in pipeline.

Lye back loop

tank, adjust the loop as seen at left side,

open circulation pump and start to backlye.


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Attentions

Startup and shutdown of lye circulation pump should be strictly accord with its operational manual. Before

startup of pump, operate the vent valve at one end of pump and vent valve of lye filter till liquid flows out, to

prevent cavitation damage to circulation pump.During Lye circulation pump works, check the indicating on time that green light on shows status is normal,

while red light on shows spare parts needs to be replaced.

, ,

injury, protective measures should be take, such as protective suit, goggles, rubber gloves, etc.

When preparing lye, make sure the filter mesh is set at the bottom of lye tank, to prevent foreign matter

entering to cause circulation pump damages.

During process 2.2.4.1, circulation rate could be adjusted by valve before flow switch (or flowmeter) as per

regulated range strictly, flow rate beyond or below the range will effect H2 quality.

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Page 18

Chapter 2.

Element replacement and maintenance in lye circulation system must be conducted in shutdown states,

lye back should be done if required.

There should be boric acid on site, if anybody contact lye, can washed by 10% boric acid solution.

Normally, lye flow is 0.4m3/h ~ 0.6m3/h.

, , .

If lye flow is low, the heat generated by electrolyzer can not be taken away, this will lead to the out

control of cell temperature.

If the signal of level is different with the real level, may be theres liquid get into level transmitter, andyou need to release liquid inside level transmitter, please note, it is very dangerous to operate H2 unit if the

pressure is kept. So please stop H2 unit and release the pressure before you do this operation.

If lye flow getting lower, this is caused by block inside lye filter, the lye filter need to be washed. When

, .

outlet need to be closed, then you can disassemble the filter.


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hydrogen systemAs seen at right, there are 3 loops after H2 separated

H2 VENTH2 VENT

from H2 separator flows into H2 washer for washing

and drop catching: first loop: H2 is vented or enters

diaphragm regulation valve; second loop is for H2

venting via manually-control vent valve, arrestor; third

H2 TO DRYER SAMPLEING

loop is for entering into sampling system to monitorH2 purity online via magnetic solenoid valve, lye

accumulator and pressure-reducing valve


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Attentions: before first operation of analysis meter, gas should be vent via by-pass line firstly, then adjust

- ,

than 0.1MPa) to prevent analysis detector from injured by over-pressure.

After pneumatic diaphragm regulation valves, two straight-through pneumatic ball valve or one

pneumatic three-way ball valve could be set according to its design requirements.

Fire arrester is application by hot conductor, due to the small pore of the heat loss and out of the principle

design and manufacture.

Pressure release valve, when you operate this valve, the direction of the valve is opposite with normal

.

There is a pressure maintaining valve on the out port of dry system, the pressure set to about 1 Mpa.

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Chapter 2.

H2 systemAs seen at right, there are three loops after O2 separated

O2 VENT O 2 VENT

from separator:

The first loop is for gas venting via pneumatic diaphragm

,

gas venting via manually-controlled vent valve; the third

loop is for entering into sampling system via magnetic valve,

accumulator tank and pressure-reducing valve for O2 puritymonitoring online.


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Attention matters:

before first operation of analysis meter, gas vents via by-pass line, adjust pressure-reducing valve to make

pressure in suitable range(slightly higher than ambient pressure, not higher than 0.1MPa). Then analysis

meter could be put into operation for preventing analysis detector injured by over-pressure.After pneumatic diaphragm regulation valves, two straight-through pneumatic ball valve or one pneumatic

three-way ball valve could be set according to its design requirements.

,

air get back into h2 unit. If H2 unit be stopped for long time, when you start H2 unit, you need to purging N2

to replace air inside H2 unit and also you need to regulate the manual ball valve to make the O2 level and H2

level same.

If we keep the pressure to 2.0Mpa or higher when H2 unit stopped, is this accepted?

The H2 regulating valve and O2 regulate valve are force open valve, why?

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hydrogen drying systemIts mainly composed of hydrogen dryers,

H2 VENT

hydrogen coolers, filter, gas-liquid separator

and water accumulator. Desiccant filled inINLET

which could continuously works for 24h,

and regenerates by means of electric heating;OUTLET

hydrogen cooler exchanges heat withregenerated gas, and separates out moisture;

filter could remove impurities in product H2;

gas-liquid separator is used to get rid of free

realizes function of second-stage water

draining; flow chart as seen at right side.2


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Power Supply

380VAC ElectricalEx lanation on the structure:heater (1) There are two cylinders combined

together; the small cylinder is in themiddle of bi c linder

Regene service

Under port(2) Inside of the small cylinder, electricalheater is installed and its power isde ended on the as ca acit .

Service flows

Regene service

(3) At the bottom of small cylinder, there istemperature sensor to detect the gastem erature Pt100

Service flows

(4) At the outlet of big cylinder, there isanother temperature sensor to detect the

as tem erature;

resistor

(5) The desiccant is filled fully in the space between small cylinder and big cylinder;

Pt100

(6) When the dryer in service, gas enters via under port and flowout from upper port;

2014-11-11 24Molecularsieve

,flows out from under port.


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Attentions:

, ,

What is water seal, what is it used for?

If you running electric heater, you have to let H2 get through dryer.

If dew point is not qualified, why?

On regeneration state, which temperature is higher Top temperature or bottom temperature?

How to know the regeneration of dryer is finished?

How the regeneration state running

The life of molecular sieve is about 3 years. How to replace molecular sieve?

When electric heater is running, H2 need to go through the dryer, or electric heater may be burnout.

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Page 26

Chapter 2.

working states :four working states, including A works, A regenerates B works, B works, B regenerates A works, cycles in

.


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Moistureseparator

Raw H2 Flamearrestor

Dryer A Dryer B

Gas cooler

Draincollector

Flamearrestor

Water sealer


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Moistureseparator


Dryer A Dryer B

Gas cooler

Draincollector

Flame arrestor Z1 state of hydrogen purificationsystem

Dryer A in regeneration, Dryer B in

service


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Moistureseparator


Dryer A Dryer B

Gas cooler

Draincollector

Flamearrestor Z2 state of hydrogen purification

system

Water sealer Dryer A in Standby, Dryer B in service


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Moistureseparator


Dryer A Dryer B

Gas cooler

Draincollector

Flamearrestor Z4 state of hydrogen purification

system

Water sealer Dryer A in Service, Dryer B in s tandby

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working sequence

The circle period is 48 hours.The regeneration state is 4 hours at most, if regeneration not finished, the state shall changed

automatically.

its forbidden to operate electric heater in dryer without gas flow which causes overheating to burn.

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Water (lye) supplementary systemWater supplementary system: deionized water from water supplementary an lye preparation unit (frame )

is pumped to H2 washer via check valve, then ball valve drive by feed-water pump, and flows into H2

separator via over-flow pipe, for diluting the liquid in H2 washer, and supplement the consumed water

.

Lye supplementary system: if electrolyte concentration decreases, add lye through pipeline connecting to

O2 separator, and pump prepared lye into O2 separator via check valve and ball valve by feed-water pump.

Form SKID


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Attentions

its forbidden to conduct water supplement and lye supplement at the same time, for it has risk of H2 and

O2 mixing.

The water supplement valve and lye supplement valve can only opened one at the same time.

Check vale leakage, if check valve leaked, there are some impurities inside valve, you should disassemble

the valve and clean the valve. And check the water tank if there are impurities on bottom and check water

.

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g

Cooling systemThe cooling water in gas-liquid processor (frame ) flows into two loops: the first loop flows into

hydrogen cooler via ball valve to cool H2 till ambient temperature; the other one loop flows into H2

separator and O2 separator via pneumatic diaphragm regulation valve to cool lye, further more to cool

, .

Attention matters:

n or er to prevent corros on an crust ng n coo ng water p pes,

deionized water is normally adopted. For customers who provides the

coolin water below re uirements closed-loo DM coolin water deviceCW Supply CW Return

is recommended to be set for providing circulation water for cooling.

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H2 storage and H2 distribution (frame )Its used to store H2 in reasonable way and distribute H2 for use according to actual pressure and flow rate.

See the photos displayed here.

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Process

As icture shown this rocess realizes

automatic control of H2 storage and H2

distribution, as well as specific requirementssuch as the successively charging, sequence

charging, ordered H2 supplement, gas charge

2 upp y

To Tank

separa es w gas re eases an manua

supplement for large amount H2, etc.

Sampling

1.2Mpa~2.80Mpa.

To User To User

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Water supplement and lye preparation unit (frame )Its mainly composed of water tank, lye tank and feed-water pump. There is a DM water supplement port

at top of water tank and at top of lye tank, a drainage port at lower part, water supplement port at lower

part of water tank and lye supplement port at lower part of lye tank are connected with inlet of feed-water

, - ,

and lye supplement. In addition, lye inlet and outlet is set on lye tank connected with frame , to

complete operation of lye preparation, lye supplement and lye release operation.DM Water Supply

To Skid

DrainTo Skid


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Lye is corrosion, and it is difficult to washed by water, dangerous! you should prepare some boric acid

(2%~3%) to wash the lye.

When lye be prepared, the solution is very hot, please take glass, rubber gloves, and do not add the KOH

fast to prevent the crystallization. If crystallization occurred inside the pipes, you can heat pipe with

boiling water to make the crystallization soft. Add V2O5 carefully!

Do not prepare more lye, or the content of KOH can not reach to 30%. Normally, add half tank water and

, , , , .

Solenoid valve leaked, because impurities inside valve, disassemble the valve and remove the impurities.Theres filters in water tank and lye tank, these filters are important, do not remove the filter.

When lye be returned back to lye tank, H2 units pressure should be released, or it is very dangerous!

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H2 storage tank

N2 replacement of H2 storage tank.Water replacement.

Pressure test. When water be used as pressure test,

t e qua ty s ou e goo , or mpur t es get nto

valves, this will lead to valve leakage.

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h f


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Chapter 3. Rectifier

componentAll rectifying parts and components installed in rectifier includes :

Thyristor, often in module with water Fast Fuserans ormer ac et toget er

Trigger Card

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Ch t 4


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Chapter 4.

rectifier structure:its front view and back view of the inside cabinet as seen here

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working principle:4.3.1 main loop:The picture at right shows the main circuit employs three-phase

.Main power supply connects to primary side of rectifier via ACcontactor, bridge rectifying is conducted under sencondary side of

recitifier )

If a thyristor is breakover, how to cut it off?

What is the condition to make thyristor running normally?

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Chapter 4


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Chapter 4.

Control loopOnce main power on, the fan at top of cabinet starts, limit switches on cabinet door could control the lights

inside; Manually-controlled and automatic-controlled startup could be chosen for start trigger board power;

there are 4 loops of interlock signals causing system ceases that outside turnoff, trigger failure, cooling

.

reset after interlock signal is eliminated.

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Chapter 4


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Chapter 4.

Trigger card

trigger board and its wiring: complete 6 items of trigger impulse control and rectifying mode switch

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pera on:working mode: constant-current running, constant-voltage running, constant-current running means

we set volta e to a certain oint then no matter what external condition chan es the volta e ke t at the

set point, the current changes as per external condition changes . constant-current running means we set

current to a certain point, then no matter what external condition changes the current kept at the set point,the voltage changes as per external condition changes .

When rectifier operated on manual mode, push button trigger start to start to provide power to

e ec ro yzer, en a us manua g ve regu a or o a us e ou pu power. en rec er runn ng

on automatic mode, rectifier started, stopped and adjusted according to control cabinets control

si nal.

Manual mode to operate rectifier, choose constant-current running mode or constant-voltage

running mode, adjust manual give regulator to lowest, then press trigger start button, increase

manual give regulator slowly to provide the power to H2 unit.

When rectifier worked on auto mode, choose constant-current running mode.

n y e s ar s gna e g ven o rec er, rec er can e opera e .

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Chapter 4.


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Chapter 4.

4.5

DC200mV

5 30


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If the current output of rectifier cannot reach electrolyzers rate value, how to check?

How to know if each thristor is working normally

If there is a problem that the electrolyzers voltage or current is abnormal, how to confirm the rectifier is

no problem?

at s t e mean ng o constant-current runn ng an constant-vo tage runn ng

How to start rectifier manual, how to stop rectifier manual, and how to stop rectifier emergency.

How to re lace th ristor?

Disassemble the broken thyristor, assemble the new thyristor, please not the positive and native ofthyristor, and connect the trigger connector with electric solding iron, heat electric solding iron

to high temperature, then cut off the power, then solder the wire, or thyristor may be broken.

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Attention

1 Rectifier cabinet com osed of man electrical elements ado ts three- hase four-wire ower su l

after it powered on, safety protection measures should be take to avoid personnel injuries;

2, For many of electrical elements are bare(mainly are rectiformer, SCR, fast fuse and bus-bar), its better not contact all electrical elements in rectifier cabinet under operation to avoid electric shock

accident;

, ec er ca ne mus opera e an run w s oor c ose , o avo acc en a con ac o e ec r ca

elements inside.

4, durin rectifier cabinet testin , checkin and re airin , at least two ersons should be at site, once

electric shock happens, the companions must cut off main power supply of rectifier instantly and

implement first aid in time.

5, once short-circuit or fire and smokes happens, operator and maintenance personnel

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Chapter 3. Control system


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Chapter 3. Control system

general descriptionAdopts control mode of PC plus PLC, PLC is core element for control system with functions of :

1, adjusting: pressure regulation system, temperature regulation system and liquid level regulation

system which is used for automatic control working pressure, working temperature and liquid level

2, displaying: to concentrate display working pressure, temperature, H2 liquid level, O2 liquid level,

H2 purity, O2 purity, dryer temperature and dew point, etc.

3, audible and visual alarms: system will set out audile and visual alarms once system pressure,

temperature, air source pressure, liquid level of H2 side and O2 side, H2/O2 purity, dew point exceeds

their limit values;

4, interlock shutdown: once system pressure, temperature, liquid level of H2 side and O2 side, lye

,Sequence control: for completing working status switching of hydrogen drying system and second-

stage water drainage control .

Regenerate control: to control regeneration heating process according to dryers upper temperature and

lower temperature .

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Page 54

Chapter 5.


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5.2.1 Pressure control system

1 Control loop for operating pressure


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1. Control loop for operating pressureP (kPa)

Operating pressure

SPRegulating valve

PV-1

O2 washer

P

O2-lyeseparator

t (s)PID regulating Curve of operating pressureSP: Set-poin t value of operating pressure

PressureTransmitter

SafetyBarrier

PIDalogrithm

E/Pconverter

PneumaticRegulating valve

+

OP

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PLCSPControl loop for operating pressure

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Chapter 5.


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Functions:

Pressure transmitter sents pressure signal at site to PLC via safety barrier, PLC compares this signal

w se va ue o pressure, an a er ca cu a on, regu a on s gna ~ m s ou pu , an en

converted to pneumatic signal 0.02~0.10MPa via electro-pneumatic convertor (or valve positioner).

O2 side ressure re ulation valve at site is driven to re ulate s stem ressure.When system pressure exceeds alarms value, visual and audible alarm signal will be sent out, while it

exceeds interlock value, system will be interlock to ceased.

Pressure-switch signal at downstream of hydrogen diaphragm regulation valve is piped into DI module

in PLC via safety barrier, visual and audible alarm signal send out once system pressure exceeds set value,

.

pressure switch signal at O2 side is connected to rectifier cabinet directly, once system pressure

exceeds set value, rectifier output will be cut which serves as hard-interlock.


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Safety barrier Isolation, Explosive-proof

Trouble shooting

Pressure transmitter calibration

Pressure transmitter draining

,

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level control system


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SP2

Regulatingvalve LV-1

- ye

levelH2-lyelevel

was er

H2-lyeseparator

O2-lyeseparator

DPT1 T2

T

t (s)

PID regulating Curve of balance of levelsT1: eriod of H2 enerator o eratin

T2: period of DM water supplementary;

T: One period ; T = T1 + T2 ;

SP1: low limit of DM water supplementary;

SP2: high l imit of DM water supplementary;

O2-lye levelTransmitter

SafetyBarrier

PIDalo rithm

E/P Pneumatic+

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-

PLCH2-level

-leve

lControl loop for balance

of H2-lye level and O2-lye level

H2-lye levelTransmitter SafetyBarrier

Page 60

Chapter 5.


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Functions:

1, liquid level transmitters at O2 side and H2 side send level signal (4~20mA) at site via safety barrier

o , compares eve as se va ue w eve , an a er ca cu a on, regu a on s gna

(4~20mA) is output, and after it being converted to pneumatic signal 0.02~0.10MPa via electro-

neumatic convertor or valve ositioner , H2 side li uid level re ulation valve at site is driven toregulate level balance by its open degree.

When liquid level at O2 side and H2 side exceeds alarms value, visual and audible alarm signal will be

sent out, while it exceeds interlock value, system will be interlock to ceased.

Feed water pump starts when H2 side liquid level is lower than HMI water feeding set value; it stops

.

Level control valve is on H2 side, is this valve can be placed on O2 side

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Chapter 5.


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Temperature control system


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H2

OT (C)

Operating temperature

O2separa or

CWS

CWR

SPseparator

electrolyzer

T

t (s)PID regulating Curve of operating temperature

SP: Set-poin t value of operating temperature

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Transmitter a e y

Barrier PIDalogrithm

E/Pconverter

PneumaticRegulating valve

+

-SP

OT

Control loop for operatingtemperature

Page 63

Chapter 5.


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Functions :

Platinum resistance set at O2 outlet of electrolyzer sends temperature signal 4~20mA to PLC via temperature transmitter, PLCcompares this signal with set value of HMI temperature, after PID calculation regulation signal 4~20mA) is output, and then converted to

. ~ . - ,

regulation valve) is driven to regulate system temperature by means of its open degree.

Lye flow shall be 0.4m3/h~0.6m3/h, why


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Page 65

Chapter 5.


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Functions:

1, Electrolysis voltage signal and electrolysis current signal of rectifier cabinet is converted into

~ m v a vo age ransm er an curren ransm er an sen o , a er s curren s gna

compared with HMI current set value by PLC, calculation could be processed under that electrolysis

volta e below the set value, and the out ut re ulation si nal 4~20mA is converted into volta ereference signal 0~15Vdc via voltage transmitter and electrolysis current could be controlled by

controlling trigger board output .

2, Visual and audible alarms will send out once electrolysis current signal and electrolysis voltage

signal exceeds alarm value.

, , .


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If no voltage/current output, how to check the reason?

If the voltage getting lower to a certain point, then suddenly the voltage and current getting to a very high

point, why?

I t eres rect er a arm ee ac , t s means t eres pro em on rect er, may e ac o coo ng water

system pressure is high/ fast fuse is broken and so on, you should check the rectifier.

Wh theres no safet barrier on this circuit?

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Chapter 5.


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5.2.5

Page 68

Chapter 5.


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4~20mA PLC PLC HMIMCC

13X 170 220~250

170

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Chapter 5.

5 2 6


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5.2.6

Page 70

Chapter 5.


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Functions:

Any measured value for analysis meters exceeds limit, audible and visual alarms will send out.

er n ana ys s me er sen s ou a arms s gna , e pneuma c a va ve or en er ng ry ng

system will be switched to vent state.

After dew oint meter sends out alarms si nal, the neumatic ball valve for dr in s stem outlet will beswitched to vent state.

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Chapter 5.

H2 storage and distribution control system


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H2 storage and distribution control system

Page 72

Chapter 5.

other subsystems


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other subsystems

Page 73

Chapter 5.

Alarm&Interlock details


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Alarm&Interlock details

System alarms include the following control points but not limited to:

system interlocks include the following control points but not limited to:

system temperature H limitH2 liquid level L limit

O2 li uid level H limit

system pressure HH m tsystem temperature HH limitH2 liquid level HH limit

O2 liquid level L limitinstrument air pressure L limitH2 purity L limit

O2 liquid level HH limitO2 liquid level LL limitflow rate L limit

O2 purity L limitdew point L limitwater tank liquid level L limit

instrument air pressure LL limit

resultant fault of rectifier cabinetOnce any point of interlock signals happen, system

regulation valve L limitOnce any point of alarm signals happen, visualand audible alarms will send out, states will be

w e cease .

switched automatically if necessary.

Page 74

Chapter 5.

functions:


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functions:

Adjustion mode: in pressure control system and liquid level control system, pressure signal and

qu eve s gna s ransm e n rea - me an on ne o w ere ac ua or ac s on ou pu po n s

directly, and PI regulation way is adopted to realize controlling; in temperature control system,

tem erature si nal measurin oint set at electrol zer outlet, actuator acts on coolin water i eline,lye is cooled by means of controlling cooling water flows in coiling pipe of H2, O2 separator, and is

circulated into electroloyzer for further control system temperature, thus, temperature controlling

system adopts PID regulation for controlling.

Circulation pump working mode: during production of hydrogen generation process, circulation

, ,

for electrolyzer; after system shutdown, after pressure releasing and temperature drop completes,

circulation pump could be stop.


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Page 76


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Attention

Firstly the gas tightness should be guaranteed. Analyzers, especially high accuracy instrument, gets

influenced easily from outside impurities, measuring date accuracy is easily affected by any tiny leaks.

ver-pressure s no a owe : ana yzer e ec or s norma y o ow pressure res s ance, over-pressure

operation for short-time makes unrecoverable injuries to analyzer detector.

Verification on time: anal zers should be verified ever 6 to 12 mouths to maintain dates accurate.

Seal maintain: under untapped status, the analyzer detector must be well sealed, nitrogen could only be

applied for sealing in necessary to avoid waste.

Page 77

Chapter 9.

FailureCause handling


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descriptionCause handling

power supply system cut; overhaul power supply system to recover

rectifier power failure;

cooling water cut or

power supply.

after eliminating following failures, reset

underpressure;

over-current interlock causes

rectifier cabinet;

check the cooling water loop, raise pressure;

Emergency

shutdown

.

fast acting fuse breaks; pressure hard interlock

replace fast acting fuse;check set value of pressure, to make outlet

control cabinet interlock causes

system shutdown(interlock point

pipeline flows smoothly;

find problems according to interlock signals

displayed on HMI;

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FailureCause Handling


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descriptionCause Handling

lye circulation rate is over-high or adjust circulation rate in suitable range;

over-low;

operation temperature is over-low;

adjust set value of temperature to 85 5

sampling test lye concentration, and dilute lye

lye concentration over-high or

over-low;

or supplement lye according to actual condition;

change lye if this problem cannot be handled;

Electrolyzer

Over-voltage limits;measured dates are not correct;

installed and verified correctly;


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Page 80

Chapter 9.



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describedCause a d g

measuring signal mistakes; check the sampling pipe, liquid section not

PID parameters setting is not

reasonable;

allowed to mix with gas, and gas section is not

allowed to mix with liquid, recalibrate it or

pressure or

Inside leaks happens in regulation

valve;

replace it if necessary;

reset PID parameters;

qu uctuates

or out of

pipeline blocks or leaks;

gas output is over-low;

clear regulation valve after system shutdown,

regulate valve rod route, check instrument air

pressure, reca rate or rep ace t necessary;

find blocks or leaks along process flow to

regulate gas output in range of 50~100%;

Page 81

Chapter 9.



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describedg

analyzer is inaccurate; check the air tight and flow rate of sampling

lye circulation rate is over-high or

over-low;

pipeline, recalibrate and replace detector if

necessary;

lye concentration is low;

water quality of raw water is

adjust circulation rate in reasonable range;

recover lye concentration by lye supplement or

gas purity drops

pressure difference between H2separator and O2 separator is over-

.

improve water quality and wash electrolyzer;reduce pressure difference by regulate

high.

liquid level of H2 separator and

control system ;

reset working liquid level to half of the

O2 separator is over-low;

diaphragm in electrolyzer breaks.

separator;

overhaul the electrolyzer;


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Page 83

Chapter 9.

described

Cause Handling


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lye flow switch failure or flow Check flow meter or flow switch, recalibrate it or

meter failure;

lye flow stop valve opens

replace spare parts if necessary;

Adjust open degree of flow check valve, do

ess or oc appens;

lye filter blocks;

circulation um failure:

was ng, c ean ng or was ng a er sassem e on

it.

disassemble and wash the filter lye alarms and

interlock inimpurities in pump;

gas influxes into pump;

check states indicating lights for circulation pump

that green area shows normal, while red area shows

system bearing wears;

locknut on impeller become

fault.

stop pump and disassemble for overhaul, replace

oose; power supply with a phase

loses

spare par s necessary.vent gas completely via vent valve;

re lace bearin .

open pump head, fasten locknut on impeller;

check power supply loops, and eliminate failures;

Page 84

Chapter 9.



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describeddew point meter is inaccurate check gas tight, flow rate of sampling pipeline,

wor ng pressure over- ow;working period is over-long;regeneration of desiccant is not

reca ra e or rep ace e ec or neccessary;adjust pressure-stabilizing valve at outlet of

drying unit, raise working pressure;

Dew point of

temperature set value is over-low; regeneration gas flow isinadequate;

,working states in time.

check process system and control systemraise set value of upside temperature and

product gas isunqualified oralarms happens;

regeneration doesnt completes.

temperature measuring elementand control elements breaks;

downside temperature of dryers;

make regeneration gas flow adequate;regeneration process should be completed, .

leaks happened inside the valvecauses gas mixed.desiccant erformance reduces.

check valves, guarantee its tightness;replace desiccant;

Page 85

PERIC


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PERIC

PERIC

Train Lecture (Indrama,Indonesia)(2xCNDQ-10)(Rev1.0)2014!11!07

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