Ammonia Slide Blok Diagram cv nghjyujkm bnmc ndfhg nvbnbmgh

7/22/2019 Ammonia Slide Blok Diagram cv nghjyujkm bnmc ndfhg nvbnbmgh

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Ammonia

Basic Flowsheet Elements


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Chemistry of the Ammonia Process


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Simplified Block Diagram of a Typical

1000 t/d Ammonia Plant


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Simplified Block Diagram of a 2000

MTPD Methanol Flowsheet

Methanol

Purification

Reforming

Compression Distillation

Synthesis

Steam Raising

Feedstock

(CH )4

Water

VHT-S103

20 m

VSG-EZ200

VSG-Z101

40 m

VSG-Z101

40 m

VSG-A101

200 m


5/22

Simplified Block Diagram of a

Hydrogen Flowsheet

Desulfurization

Primary Reforming

High Temperature

CO Shift

VHT-S101

VSG-

Cl101

VSG-

EZ200

VSG-

Z101

VSG-

F101

PSA

etc

SteamNatural Gas Feed

Hydrogen


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Simplified Flowsheet for a Typical

Ammonia Plant

NaturalGas

Steam

superheater

Air

Steam

30bar

Steam

Steam

raising

350 C200 C

HeatRecovery

Steam

raising

Cooling

Cooling

Reboiler

CO

Cooling

Preheater

Heat

Recovery

Steam

Boiler

ProcessCondensate

Quench

Quench

Liquid Ammonia

H

Hydrodesulphuriser PrimaryReformer

SecondaryReformer

HighTemperature

Shift

LowTemperature

Shift

Ammonia Syn thes isMethanator

Carbon Dioxide

Purge Gas

Cooling

400 Co

390 Co

2

790 Co

550 Co

1000 Co

o

420 Co

150 Co

400 Co

470 Co

o

220 Co

290 Co

330 Co

2

CO Removal2

220 bar

Refrigeration

CondensateCooling

Ammonia

Catchpot


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Modern Conventional Flowsheets

Main process steps are the same for all plants

Main differences in equipment design

Uhde

Top fired reformer

Proprietary exit header design

Secondary reformer has a riser

HP loop with radial flow converter


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Modern Conventional Flowsheets

HKBR

Primary reformer with manifold/riser

Haldor Topse

Side fired reformer

Radial flow converter

S-200

S-250


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Other Flowsheet Options

Braun Purifier

ICI AMV

ICI LCA

Dual Pressure Uhde Process

HKBR KAAP (with/without purifier)

Linde LAC H2 Recovery is used on most

modern plants


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Braun Purifier Process

Primary reformer exit temperature is 700C

Excess air is added to the secondary reformer

Methane slip typically around 2-2.5 mol %

Excess nitrogen (and methane) cryogenicallyremoved downstream of methanator

Also removes water - ammonia synthesis catalystpoison

Improved synthesis lives Can reduce SC ratio to 2.7-3.0

Small primary


11/22

Braun Purifier Process

Cold Box

Purified Syn Gas

Waste Gas

Raw Syn Gas

Feed Effluent Exchangers


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ICI AMV Process

As with Braun - utilizes excess air to secondary

Excess nitrogen is passed to the loop

Loop runs at low pressure (80-110 bara)

Use ICI LP Catalyst (74- Series) Uses a saturator to saturate feed gas

This raises around 50% of the required steam

Can use SC ratio of 2.8

H2Recovery in loop at loop pressure


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ICI LCA Process

Aim at small plant capacities (500 mtpd)

Uses the GHR-Secondary concept

Excess air is utilized to close heat balance

Utilizes an ITS rather than HTS and LTS A saturator for steam raising

A PSA system to remove the CO2 and excess N2

A low pressure loop (80 bara)

A tube cooled converter or Casale converter

No longer actively marketing


14/22


PGR Unit

Make up gas

from frontend

H2O

Ammonia from once through conversion

HP-

steam

C.W.NH

3NH3

C.W.

C.W.

C.W.

HP-

steam

NH3 NH3

Off-Gas

Ammonia

fromHP loop

HP

casing

LPcasing

Firstammonia

converter

Secondammonia

converter

Once

through

ammonia

converter

HP-

steam

Note: Molecular

Sieves not shown


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Benefits of such a scheme realised at 3,000

mtpd +

Although this is large capacity - all equipment is

proven Note the low pressure converter between stages

of synthesis gas machine

Makes machine smaller Makes loop pipework 24

Uses Comp. J catalyst


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HKBR Purifier and KAAP

Primary

Reformer

Secondary

Reformer

Shift &

CO2Removal

Purifier

CompressionKAAP

Methn

Dryers

Recycle Purge

To Fuel

Feed


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Linde LAC

Key features are

No secondary reformer

Nitrogen is generated cryogenically and

added after a PSA unit

No HTS/LTS - only Isothermal (ITS) shift

No methanation


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Linde LAC

Desulfurization

Primary Reformer

Isothermal Shift

PSA

Nitrogen Unit

Ammonia Synthesis


19/22


Use Gas Turbine to drive process aircompressor

Can use effluent as combustion air

Has 16-17% O2and is at 500C

Braun plants

Install pre reformer

HT Retrofit Many other reasons

Remove heat from duct

Uprate plant


20/22


Synthesis Gas driers

Reduces H2O in syn gas

H2O is a poison

Activity increases

Ammonia Wash

As per Syn Gas driers

Booster converters Drop load on loop and allow overall output

increase

Quenches in Shifts


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Ammonia Flowsheet Data Analysis

Tool - VULCAN CERES Looks at all catalytic unit operations

Highlights potential issues/in-correct data

items

Functionality to address flowsheet options Kellogg risers

Differential flowsheet conditions (Braun)

Use as a basis for

Predictions of future performance

Predictions of new catalyst options

Uprates


22/22

Ammonia Slide Blok Diagram cv nghjyujkm bnmc ndfhg nvbnbmgh

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