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7/31/2019 Acetylene Reacor Abb

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IndustrialIT for Acetylene/MAPD Hydrogenation

Creating value through integrated solutions

Improve acetylene/MAPD hydrogenation safety,environmental and economic performance


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Improve acetylene/MAPD hydrogenation safety,environmental and economic performance

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Overview

Petrochemical companies continuously strive to

enhance th e profitabilty of th eir ethylene p lantoperations as they face the ongoing challenges

of an increasingly competitive industry. Growing

competition from low-cost feedstock prod ucers,

tightening environm ental regulations, and

increasingly volatile feedstock and energy costs

all contribu te to the n ecessity of operating plants

at maximum efficiency and reliability.

T he selective hydrogenat ion o f acetylenes is a key

un it operation within the ethylene process and can

make a significant cont ribution to the efficiency

gains dem anded by t his competitive operating

environment. O ptim ization of th is critical processstep results in enhanced olefin yields, consistent

delivery of on-specification product, and lower

utility costs, resulting in significant improvements

in overall plant operating economics. In addition,

the ever present risk of reactor runaways and

produ ct flaring can be reduced, minim izing

operational impact on employees and local

comm un ities, wh ile com plying with emission

legislation.

ABB offers a unique IndustrialIT solution for

Acetylene/M APD H ydrogenation Un its to assist

operating comp anies in meeting th e significantchallenges of todays operating environment that

are of critical importance from financial and

reputation perspectives.

O ur leading t echnology for acetylenehydrogenation u nits is mu ltivariable, mod el-predictive control that exploits our capabilityfor real-time analysis of feed and intermediatestreams within m ulti-converter un its. T his uniqueapproach can help operators maximize olefingains and avoid the comm on p roblems leadingto plant u psets and perform ance deterioration.

O n-line measurement of conversion andselectivity available in real-time for all catalystbeds delivered by our leading analyticaltechnology.

Process analytical technology for hydrogen andolefin p roduct quality helps to improve reactoryields and ensure continuous availability of on-specification produ ct.

A complete service portfolio including fieldservices, on -line support, training and parts/repairin order to maintain the performance of your

IndustrialIT solution.


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IndustrialIT for Acetylene/MAPD Hydrogenation

Industrial IT for Acetylene/MAPD Hydrogenation

Emp loys our uniqu e capability for real-time, on -line measuremen t

of con version and selectivity. A low cost option to improve olefin selectivity and reduce product

flaring incidents.

Achievable benefits of $2-3M per plant.

You have the insurance that other leading operating comp anies

are already enjoying the benefits of our acetylene hydrogenation

unit technology which reduces your risk and assists in local

justificat ion of p roject expen se.

Allows for simple and synergistic upward migration to the

entire family of olefin plant solutions from ABB.

All elements can be seamlessly integrated into your existing unit.

O perators can ob tain a comb ined analytical and cont rol solution from

one vendor, delivering unique synergistic benefits to the operation

of acetylene converters. This leads to enhanced unit reliability and

selectivity while ensuring safe operation .

Acetylene Hydrogenation Unit Operations

O peration of acetylene hydrogenation un its (AH Us) is a difficult un dertaking

and subject to th e most testing of operating regimes. This is due to a nu mb er

of industry specific constraints and operating issues that stretch the processing

capability of the units.

Operating issues

AH Us m ust be able to d eal with feedstocks that rou tinely vary in bot h

acetylene cont ent and volum e due t o up stream operating complexities,

while maximizing olefin gains and availability of on-specification product.

T hey mu st operate in a safe man ner despite the ever-present and real

concerns of therm al runaways caused b y non -routine operations

or poor reactor control.

O peration m ust m eet run -time an d selectivity objectives for the catalyst

as the formation of heavier by-products adversely impacts olefin yields,operating cycle length and regeneration frequency.

T he dem ands on t he acetylene hydrogenation u nit are further increased

due to ongoing trends within t he ethylene indu stry.


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Industry issues

Case study 1 North American Ethylene Plant

A North American ethylene plant has recently installed ABB technology for improved control of acetyleneand M APD hydrogenation units. The variable nature of unit feeds had been causing significant disturbances

to the optimum operation of the converters. The problem was compounded by the slow response of existing

conventional analyzers and poor performance of inferential measurements. Fluctuations in raw C2 feed and

inter-bed acetylene content led to poor hydrogen ratio control which resulted in a number of flaring incidents.

As well as the obvious economic penalties associated with such events, the operating company was

extremely concerned about the environmental compliance and local community impact of such incidents.

To mitigate these events, our real-time analysis technology for feed and inter-bed streams has been

employed. The operator is targeting a reduction in flaring of at least two incidents per year coupled with

improved olefin yields.

Industry trends

Increased cracking feedstock flexibility.

Proliferation of plant revamps as existing producers preferentially gainadditional capacity at lower incremental costs compared to construction

of grass roots units.

A continuing trend towards higher severity cracking operations.

Ever increasing dem ands from consumer plants and polymerization

technology for improved availability and quality of olefin feedstock.

All of these scenarios result in on going demands on the AH U to be m ore

flexible in handling increased and varying acetylene contents, while enhancing

unit reliability and olefin quality.

Environmental issues

T he who le petrochemical indu stry is subject to ever-tightening environment al

legislation.

Regulations continue t o drive towards minimizing emissions and m uch

effort is made by operators to improve, mon itor and report environment al

performance.

Penalties for non-compliance are expensive from financial as well as

reputation perspectives.

Compliance agencies are reluctant to grant operating waivers for flaring

incidents that result in increased emissions over and above permitted levels.

O ff-specification operation of AH Us comm only results in a num ber of suchinciden ts on a yearly basis.

Indu stry trends, complex operating conditions and m ore stringent

environmental compliance all contribute to increasing difficulties of operating

acetylene h ydrogenation units. To m eet these challenges, it is more im portan t

now than ever, that these units improve olefin product yields, reliability and

operat ional flexibility.


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Meeting the challenges

What are the options for Acetylene/MAPD Hydrogenation

Unit operators?

Furth er technical development s and imp rovemen ts in acetylene/M APDhydrogenation m ust m eet these increasing op erational challenges. AH U

technology must be h ighly focused on economic, safety and environm ental

compliance issues while improving operability of current operations. In the last

few years, the first choice of many operators has been to install new technology

supplied by the catalyst industry. This approach has been successful in improving

man y of the operating prob lems and challenges experienced in AH U operations.

H owever, despite these improvements, a nu mber of historical challenges still exist

that significantly hinder the opt imum economic and safe operation of th ese

units. In this respect, improved process control of existing assets can further

enhance unit operability. Advanced process control is always one of the most

efficient, low cost actions that is undertaken by the operators of any process unit.

M any of th e ongoing operating p roblems affecting AHU s are a result of less than

optim um process control of key unit targets.

Depending on whether the acetylene/MAPD hydrogenation is carried out in

front-end or tail-end m ode, th ere are a nu mb er of different d isturb ance variables

that affect th e operation of the unit.

In addition, p rocess control is more comp licated in t he case of mu ltiple

converter-beds while iso-therm al or adiabatic operation add further individual

deman ds to the imp lemen ted control scheme. H owever, the prim ary disturban ce

variables in all configurations are feedrate, raw olefin stream composition

(especially acetylene/MAPD content) and in some cases, hydrogen purity.

T hese disturban ces are routine occurences within ethylene u nits and can

be caused by: Furnace shutdowns Severity changes Feed-type switches Fractionation p lant upsets

These variations significantly challenge the ability of the control

scheme to continuously achieve:

Safe unit operation O n-specification product availability Reduced flaring Improved selectivity O lefin yield gains across the un it Low by-produ ct formation Acceptable run-lengths and regeneration frequency

T hese and ot her comm on AH U operating challenges that h ave been experienced

for many years in the industry can now be managed by the application of ABBs

Acetylene/MAPD Hydrogenation IndustrialIT Solution. Operators that have

been limited in their ability to deal with day to day up sets due to these

un controllable disturban ces, can now maintain opt imum control of AH U

un it operations. T his leads to significant improvement in un it economic,

safety and environm ental performance.


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Industrial IT for Acetylene/MAPD Hydrogenation

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Hydrogen: Acetylene ratio control

Common Operating Problems The m ajority of p lants run with poor hydrogen:acetylene ratio control resulting in:

lower reaction selectivity lea ding to reduced o lefin gains (or net losses) ac etylene slippage c ausing off-spe cification product and flaring closer approa che s to runaway conditions higher green oil p roduction lea ding to increase d regenera tion frequency and shorter c ata lyst life produc t downgrades to ethane (or propa ne) w ith assoc iated recyc le costs.

The poor ratio control is further deteriorated by rapid feed compositional changes which are not adeq uately trackedby the slow ana lytical response of traditional analyzers. These include c hanges in acetylenic content a s well as heavyends from upstream fractionation upsets.

During plant upsets, operators tend to ramp up to excessive hydrogen addition rates in order to a bsolutely maintainon-spec ification product. This causes ex tremely high olefin losses due to greatly reduced selectivity and the reactoris usually held in this condition for far longer than the duration of the initial incident.

SolutionImplementation of ABB multivariable control technology driven by our unique capa bilty of real-time fee d and mid-be dstream characterization, allows these com mon operating problems to be solved.

Feeds to lead and gua rd beds are charac terized in real-time providing a true hydrogen demand p icture leading to optimumhydrogen ratio control. This unique ca pability is inherently more effective tha n traditional approaches to ratio control whichrely on slow feed back from gas chromatographs. As part of a wider multivariable control scheme, this app roach will lead toimprovements in olefin yields compared to conventional baseline APC performance. In a ddition, plant upsets are smoothlymanage d, eliminating operator initiated overhydrogenation for extended p eriods of time.

Conversion and selectivity optimization

Common Operating Problems Operators are c urrently limited in their capa bility to rapidly and accurately track bed conversion and selectivity performance.

Current methods include the use of reac tor temperature differentials or slow feedbac k from gas chromatographs. The sub-optimum performance of these approaches is further compounded when feed composition is subject to rapid changes. Thefollowing problems are evident in many units:

Operating campaigns are extended beyond the optimum regenera tion point in the cyc le as olefin yield losses are not rapidlyor accurately determined.

Conversion is conce ntrated too muc h on the lead reactor, which as well as reducing se lectivity, results in a ccelerate d foulingof the bed and shorter run-lengths.

Heavy end s from upstrea m fra ct ionation upsets can enter the reac tors undete cte d a nd cause selectivity losses, catalyst/exchanger fouling and closer approaches to runaway conditions.

Rap id a nd large ethylene losse s cannot be determ ined quickly enough to definitively indicate runaway conditions.

SolutionThe implementation of ABB PIR3502 photometer technology allows these common operating problems to be solved. Ethylene,ethane and acetylene content of lead and guard bed feeds can be determined in real-time. In addition, the ethylene and ethanecontent of guard be d effluent is measured. The ana lagous components for M APD hydrogenation units are also determined in real-time by the ABB technology. For the first time, an operator can track conversion and selectivity across the converter beds, in real-time. Furthermore, heavy-ends can be detected in lead bed feed by tracking propylene or butadiene in C2 and C3 hydrogenationunits respectively.

The ava ilability of real-time conversion and selectivity data is a key eleme nt of ABBs multivariable control approach and results inindustry leading safety, economic and environmental performance for acetylene and M APD hydrogenation units.


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5

3Hydrogen quality

Common Operating Problems CO spikes in hydrogen feed can oc cur due to ope rating problems in upstream methanation or pressure swing adsorption

(PSA) units.

For CO moderated ca talysts, poor control of methanation or PSA reactor bypass can lead to sub-optimum ca talyst operationand olefin losses.

SolutionABB offers our PGC 2 000 ga s chromatograph and Advanc e Optima tec hnology for hydrogen quality measurements. The traditionalapproach to hydrogen quality measurement in ethylene plants has been ga s chromatography and ABB has installed ma ny such unitsin this duty. Our Advance Optima U ras 14 has also be en used extensively for hydrogen quality measurements, providing continuousreal-time chracterization. Faster hydrogen quality measurements can rapidly detect p rocess upsets and so prevent cata lyst problemsand a ssociated operational penalties. The rapid a vailability of hydrogen quality is a key e lement of ABBs multivariable controlpacka ge for acetylene hydrogenation units.

4Hydrogenated C2/ C3 product quality

Common Operating Problems Unreliable a nalyzer feedback resulting in:

acetylene contamina tion of downstream fractiona tion tow er hydroge n slippage to product which reduc es reac tion selectivity and requires pasteurization of ole fin product in

downstream splitter poor se lectivity c ontrol due to slow feedback of ethylene and ethane c ontent (or propylene and propane in M APD units)

SolutionFor these key mea surements in the ethylene process, our approach includes our PGC 20 00 gas chromatograph for hydrogen andacetylene measurements, and our PIR3502 photometer technology for real-time indication of ethane and ethylene content of theguard bed e ffluent stream.

The reliability of our technologies for these ap plications has been rewa rded w ith the leading supply position within the ethyleneindustry. Operators c an rely on the p erformance of our analytical solutions to help them make operational decisions regarding olefinproduct quality which can have huge ec onomic implications for the ethylene unit and downstream consumers.

MAPD hydrogenation

Common Operating Problems In comm on with C2 hydrogenation units, these converters commonly operate w ith poor hydrogen:acetylene ratio control resulting in:

lower reaction selectivity lea ding to reduce d p ropylene gain M APD slippage c ausing off-specification product highe r green oil production

produc t downgrades to propane with associated re cycle c osts

The poor ratio control is further deteriorated by rapid fee d comp ositional changes which are not adequately tracked by the slowanalytical response of traditional analyzers. This includes changes in M APD content as w ell as heavy ends from upstreamfractionation upsets.

In addition, unique problems associated w ith MAPD hydrogenation units include:

The strongly exothermic hydrogenation of MAPD compone nts coupled with the presence of hea vy ends in the feed causeaccelerated by-p roduct formation leading to shorter catalyst run-lengths. Breakthrough of butadiene from upstream fractionationupsets also ca uses reduced selectivity. This is commonly solved by ope rator induced overhydrogenation which is usuallyimplemented for exce ssive periods.

Operating safety dem ands that the significant exotherms expe rienced in MAPD hydrogenation be tightly controlled. This iscommonly achieved by recycling lead be d product in liquid phase two-b ed systems in order to limit the MAPD content in freshfeed. P oor ratio control of this step is comm on with unnecessary large recycles lead ing to poor c onversion/selectivity control,higher energy costs and risk of over-evaporation of liquid in the reactors. This challenge is further compounded by rapid feedcomposition changes.

Less commonly, M APD hydrogenation is carried out in the vapor phase. These units are well known to exhibit low propylenegains or net losses throughout their operating cycle due to poor selectivity. High green oil production is also a common occurence.These intrinsically poor characte ristics of vapor phase C3 systems a re further exacerbated by poor c ontrol of disturbances in feedcomposition leading to unacc eptab le olefin losses and run-lengths.

SolutionImplementation of ABB multivariable control technology driven by our unique capa bilty of real-time feed and mid- bed streamcharacterization, allows these com mon ope rating problems to be solved.

Feeds to lead and guard be ds are characterized in real-time providing a true hydrogen dem and picture leading to optimum hydrogenratio control and efficient manage ment of hea vy end breakthroughs. This unique ca pability also allows liquid recycle ratio control to beprecisely controlled as feed and lead bed e ffluent M APD contents are de termined in real-time. Application to vapor phase systems canmitigate the intrinsically poorer performance o f these systems leading to olefin gains and ac cepta ble run-lengths.


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Benefits of Industrial IT for Acetylene/MAPD Hydrogenation

Case Study 2 North American Ethylene Plant

A North American ethylene plant has been using ABB analytical technology for real-time feed and

intermediate stream characterization for over 10 years. Like all operators of front-end hydrogenation

units, the company had a critical need for rapid CO and acetylene measurements in lead bed reactor

feed. The main drivers were prevention of runaway conditions and optimization of ethylene yield gains

across the converter. In addition, the capability for determining CO and acetylene in lead reactor effluent

was also implemented in order to optimize the guard reactor.

Both analyzers have operated successfully during this period resulting in huge payback for the

operating company.

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1 Hydrogen:Acetylene Ratio Control

Setting hydrogen addition rates based on the real-time characterization of lead and

guard bed feeds offers several advantages to the operator. This unique capability from

ABB is inherently more effective than traditional APC approaches which rely upon

slow analyzer feedback.

Average hydrogen:acetylene ratios are lowered even in those operations thathave already imp lemented t raditional advanced pro cess control in an att emptto im prove baseline un it performance.

Flaring incidents are reduced as the hydrogen ratio is maintained consistently,without dead-time effects, resulting in higher availability of on-specificationethylene product. Annualized savings associated with reduced flaring are in therange of $1 - 2M depending on current b aseline reactor p erformance. (basis: 1billion pound per annum ethylene unit).

Ethylene yields are increased due to improvements in olefin selectivity across theconverter beds. Implement ing traditional APC can im prove olefin yields (as apercentage of feed) by up t o 0.5% . Th e enhanced ABB approach can furth er

improve olefin yield gain by another 0 .2% . For a billion poun d p er year ethyleneplant th is results in average benefits of $1.5 - 2 .1M per ann um . In addition,ethane recycle is reduced resulting in lower utility costs.

Less frequent approaches to runaway conditions are experienced as precisehydrogen ratio control avoids overhydrogenation and r apid ethylene consum ption.

Plants can finally realize the expected gains of recent investments in state of the artcatalysts by truly exploiting their enhanced capability for lower hydrogen:acetyleneratio operation. Many plants still run hydrogen ratios on the safe side despitehaving implemented capable catalysts.

Reduce green oil formation an d t he n eed for large inlet tem perature increases tomaint ain un it conversion. Lowering by-product formation will improve olefinselectivity and reduce the need for bed regeneration which ultimately leads to

shorter catalyst life. In addition, as the catalyst proceeds through its normaloperating cycle, optim um hydrogen ratios can be m aintained by tracking un itperformance in real-time and so avoiding unecessary inlet temperature increases.

Maintain optimum ratio control during plant upsets when operators havehistorically ramped up to excessive hydrogen addition rates. This avoidsunnecessary overhydrogenation for periods exceeding the lifetime of theincident . Real-time determ ination of acetylene as well as heavies allows rapidintervention by th e advanced process control scheme.


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3

Conversion and Selectivity Optimization

Many of the benefits associated with optimization of converter selectivity and

conversion are coincident with those achieved by tighter hydrogen:acetylene

ratio control. H owever, th e operator can gain additional benefits from the real-

time tracking of these critical operating variables.

T he optim um balance of run-length m anagement and ethylene yield gains

can be achieved by real-time indication of conversion and selectivity

throu ghout an operating cycle. Plants can avoid th e all too comm on p roblem

of keeping a reactor on-line for too long due to delayed or unreliable

secondary correlation feedback on reactor performance. These events result

in un necessary olefin yield losses.

Catalyst p oisoning in cidents can be rapidly detected and man aged as th ey

instantly affect conversion and selectivity of the reactor.

Real-time conversion and selectivity data allows the operator to distribute

conversion more evenly between lead and guard (or multiple) beds which

can be beneficial during the course of a catalyst operating cycle. The real-time control reduces the risk of acetylene breakthrough wh ile obtaining

benefits in bed lifetime and selectivity.

Provides primary evidence of an approach to ru naway conditions in addition

to reactor temperature m easurement s. T he continu ous real-time

measurement of ethylene and ethane cont ent in reactor effluent streams

(all beds), helps avoid unnecessary process interventions or shutdowns due

to instrum ent reliability issues or operator dou bt. More imp ortant ly, this

capability allows operators to take definitive steps to mitigate potential

excursion s in t heir early stages.

Track heavy ends (p ropylene and butadiene) in C 2 and C 3 feeds respectively

and avoid reactor fouling, loss of selectivity and approaches to runaway

conditions.

Hydrogen Quality

Rapid, on-line determination o f H 2 quality allows the operator to:

Prevent off-specification slippage of acetylene to ethylene product due

to inadequate h ydrogen ratio cont rol.

Implement optimu m control of CO injection systems or methanator

bypass rates for C O -moderat ed catalysts and so increase olefin yields.

D etect up sets in upstream m ethanation or PSA systems causing C O spikes.

Hydrogenated C2/C3 Product Quality

For this key measuremen t in the ethylene process our appr oach includes our

PG C 2 000 gas chrom atograph for hydrogen and acetylene m easuremen ts and

our PIR 3502 phot ometer technology for real-time indication of ethane and

ethylene contents.

O perators can rely on t he performan ce of our analytical solutions to h elp t hem

make operational decisions regarding olefin product quality which can have huge

economic implications for th e ethylene unit and d ownstream consumers.

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5

Hydrogenated C2/C3 Product Quality (continued)

Reliably detect acetylene and prevent contamination of downstreamfractionation.

Reduce hydrogen slippage to product which impacts reaction selectivity

and p asteurization load of the d ownstream C 2 splitter.

O ptim ize selectivity control with real-time feedback of ethylene & ethane

content (or propylene and propane in M APD units).

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MAPD Hydrogenation

T he deman d for additional propylene as C3 derivative consump tion

rates increase, makes imp roved M APD hydrogenation an imp ortant

source to help meet predicted produ ct deman d. ABB can p rovide a

unique multivariable control approach for optimum control of MAPDhydrogenation units and so increase propylene yield gains across converter

beds. O ur techn ology is underpinn ed by real-time feed and m id-bed

stream characterization leading to optim um hydrogen ratio control and:

Improved reaction selectivity resulting in additional propylene in

tandem with lower propane recycle costs.

H igher availability of on-specification prop ylene prod uct.

Un ique benefits of our approach also include:

Rapid m anagemen t of C 4 breakthroughs caused by up stream

fractionator upsets which reduce selectivity and result in prolonged

periods of overhydrogenation due to excessive operator intervention. Safer operations by imp roved m anagement of M APD hydrogenation

exotherm s. Th is is achieved b y precise ratio cont rol of recycled

lead bed produ ct in liqu id phase two-bed systems. Fresh feed and

recycle stream M APD concentrations are determined in real-time

allowing precise attainment of target MAPD levels in reactor feed.

As well as the primary gain of improved safety, significant economic

benefits are attain ed by elimin ating u nn ecessarily large recycles. T his

leads to improvements in conversion/selectivity control, lower energy

costs and reduction in over-evaporation in the reactors.

O perating imp rovemen ts to vapor phase M APD h ydrogenation.

The characteristically low propylene gains (or net losses) and high

green oil production associated with this process can be significantly

improved by application o f our u nique m ultivariable control approach.

In tan dem with improved management o f feed disturbances, our

technology can turn olefin losses into gains and extend catalyst

run-lengths.


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Summary

ABB offers a unique IndustrialIT solution for

Acetylene/MAPD Hydrogenation to assist

operating companies in meeting thesignificant challenges of todays operating

environment that are of critical importance

from financial and reputation perspect ives.

Our leading technology for acetylene/

MAPD hydrogenation is multivariable,

model-predictive control that exploits

our capability for real-time analysis of

feed and intermediate streams within

multi-converter units. This unique

approach can help operators maximize

olefin gains and avoid the commonproblems leading to plant upsets and

performance deterioration.

On-line measurement of conversion and

selectivity available in real-time for all

catalyst beds delivered by our leading

PIR3502 photometer technology.

Process analytical technology for

hydrogen and olefin product quality

helps to improve reactor yields and

ensure continuous availability of on-

specification product.

A complete service portfolio including

field services, on-line support, t raining

and parts/repair in order to maintain the

performance of your IndustrialIT

solution.

For the first time, operators can obtain a

combined analytical & control solution for

acetylene/MAPD hydrogenation from one

vendor, delivering unique synergistic

benefits to the operation of these important

unit operations within ethylene plants. This

leads to enhanced safety, economic and

environmental performance.

For more information, please visit us at

www.abb.com/analytical

11

Front End Hydrogenation

Althou gh th e m ajority of ethylene plants employ tail-end hydrogenation

schemes, a significant n um ber of front-end hydrogenation un its are in

operation. These are particularly evident in gas fed crackers where the

hydrogenation un it feed can be C3

or lighter bu t is more comm only C2

an d

lighter. The front -end app roach is attractive for a n um ber of reasons including

long cycle lengths, improved energy efficiency and lower capital expenditures.

Common Operating Problems

Particularly in front-end de-ethanizer schemes, the operation is sensitive to

CO fluctuations.

Rapid in creases in C O can lead to off-specification prod uct for acetylene if

the cont rol scheme d oes not react quickly and man ipulate inlet t emperatures.

Rapid decreases in C O are far m ore serious and will result in temp erature

excursions (runaways) due to the hydrogenation of ethylene given the

abund ance of hydrogen in th e feed. T hese events n ot on ly result in off-

specification product but also limit catalyst cycle lengths and produce large

olefin product losses.

Un planned slippage of M APD into th e feed of front end de-ethanizer

converters naturally tempers catalyst activity. If its presence is not rapidly

detected, the cont rol scheme cann ot com pensate quickly enough t o avoid

significant activity decreases and p oten tial acetylene slippage to ethylene

product.

In front end d e-propanizer fed units, breakthrough of h eavy ends in the

reactor feed cause accelerated catalyst fouling, further compounding the

intrinsically higher rate of green oil formation due t o t he higher reactor

exotherms associated with simultaneous C 2 and C 3 hydrogenation.

Solution

Imp lemen tation o f ABB multivariable control technology driven b y rea l- ti m e

feed and lead-bed effluent characterization, results in significant improvements

in th e safety and econom ic perform ance of front-end hydrogenation un its.

Real-time determ ination of CO and acetylene in reactor feed and in termediate

streams leads to better con trol of inlet bed temp eratures. T his approach can

mitigate the product quality penalties associated with rapid increases in feed

CO content an d m ore importan tly, reduce the risks of temp erature excursions

leading to reactor runaways.

Acetylene Extraction Units

For those ethylene plants that operate acetylene extraction units, attractive

benefits can also be gained by the application of ABBs unique multivariable

control technology driven by real-time acetylene measurements.

Reduce utility and make-up solvent costs in recycle loops

Minimize ethylene slippage to acetylene product

Improve safety profile


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Copyright 2003 by ABB Inc. All rights to trademarks reside w ith their respective owners.

Specifications subject to change w ithout notice. Pictures, schematics and other graphics cont ained herein are published for illustration purposes only and donot represent produc t configurations or functionality. User doc umentation acco mpanying the product is the exclusive source for functionality descriptions.

IndustrialIT Solutions from ABB

Industrial IT solution s from ABB blend the

industrys broadest portfolio of compatible

know ledge com po nents with a p roven

architecture for real-time enterprise

automation and information .

Visit us at:

www.abb.com/analytical

Email: [email protected]

Analytical and Advanced Solutions

585, boul. Charest est, Suite 300Quebec (Quebec) G1K 9H4CanadaTel: 418 877 2944Fax: 418 877 2834

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