Plantilla de excel para aplicar la metodología HazopDescripción completa
Sample of a HAZOPFull description
hazop silDescripción completa
hazopFull description
Study Node: Oxidation Reactor Process : Oxidation of p-xylene to Terephthalic Acid
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Plantilla de excel para aplicar la metodología HazopFull description
Hazard and Operability Analysis example.Full description
Hazop
HAZARD AND OPERABILITY STUDY OVERVIEW
A hazard hazard and operability operability study (HAZOP) (HAZOP) is the recomme recommended nded method method for identifying identifying hazards and problems that present safe and efficient operation. The technique is based on the principle that seeral e!perts "ith different bac#grounds can interact in a creatie$ systematic fashion and identify more problems "hen "or#ing together than "hen "or#ing separately and combining their results. The essence of the HAZOP Analysis approach is to reie" process dra"ings and%or proc proced edur ures es in a serie series s of meet meetin ings gs$$ durin during g "hic "hich h a mult multi&d i&dis iscip ciplin linary ary team team uses uses a prescr prescribed ibed protoc protocol ol to metho methodic dically ally ealua ealuate te the signific significanc ance e of deiati deiations ons from from the normal design intention. The primary adantage of group participation in a HAZOP Analysis is that it stimulates creatiity and generates ne" ideas. This creatiity results from the interaction of a team "ith "ith diers dierse e bac#gr bac#groun ounds. ds. 'onse 'onseque quently ntly$$ the success success of the study requires requires that that all participants freely e!press their ie"s$ but participants should refrain from criticizing each other to aoid stifling the creatie creatie process. process. This creatie creatie approach$ approach$ combined combined "ith the use of syste systemat matic ic protoc protocol ol for e!am e!amini ining ng hazard hazardous ous situatio situations$ ns$ helps helps impro improe e the thoroughness of the study. study. The HAZOP study is focussed on specific points of the process or operation called study nodes$ process sections$ or operating steps. One at a time$ the HAZOP HAZOP team team e!amines e!amines a study node using a set of established guide "ords to identify potentially hazardous proces process s deiations deiations.. One purpos purpose e of the guide guide "ords "ords is to ensure ensure that all relea releant nt deiations deiations of process paramete parameters rs are ealuated. ealuated. ometim ometimes$ es$ teams teams consider consider a fairly large number of deiations (i.e.$ up to *+ to ,+) for each section or step and identify their potential causes and consequences. consequences. -ormally$ -ormally$ all of the deiation for a gien section or step are analyzed by the team before proceeding further. Table * lists terms terms and definitions definitions that are comm commonly only used used in HAZOP HAZOP Analy Analysis. sis. The guide "ords sho"n in Table , are applied to process parameters such as those sho"n in Table .
*
TABLE 1 Common HAZOP Analysis Terminoloy Term
De!ini"ion
Pro#ess Se#"ions $or S"%&y No&es'
ection of equipment "ith definite boundaries (e.g.$ a line bet"een t"o essels) "ithin "hich process parameters are inestigated for deiation. The locations on P/01s at "hich the process parameters are inestigated for deiations (e.g.$ reactor)
O(era"in S"e(s
1iscrete actions in a batch process or a procedure analyzed by a HAZOP analysis team. 2ay be manual automatic or soft"are& implemented actions. The deiations applied to each step are some"hat different than the ones used for a continuous process
In"en"ion
1efinition of ho" the plant is e!pected to operate in the absence of deiations. Ta#es a number of forms and can be either descriptie or diagrammatic (e.g.$ process description$ flo"sheets$ line diagrams$ P/01s)
)%i&e Wor&s
imple "ords that are used to qualify or quantify the design intention and to guide and stimulate the brainstorming process for identify process hazards
Pro#ess Parame"er
Physical or chemical property associated "ith the process. 0ncludes general items such as reaction$ mi!ing$ concentration$ pH$ and specific items such as temperature$ pressure$ phase$ and flo"
De*ia"ions
1epartures from the design intention that are discoered by systematically applying the guide "ords to process parameters (flo"$ pressure$ etc.) for each process section. Teams often supplement their list of deiations "ith ad hoc items
Ca%ses
3easons "hy deiations might occur. Once a deiation has been sho"n to hae a credible cause$ it can be treated as a meaningful deiation. These causes can be hard"are failures$ human errors$ unanticipated process states (e.g$ change of composition)$ e!ternal disruptions (e.g.$ loss of po"er)$ etc.
Conse+%en#es
3esults of deiations (e.g.$ release of to!ic materials). -ormally$ the team assumes actie protection systems fail to "or#. 2inor consequences$ unrelated to the study ob4ectie$ are not considered
Sa!e%ar&s $Pro"e#"ion'
5ngineered systems or administratie controls designed to preent the causes or mitigate the consequences of deiations (e.g.$ process alarms$ interloc#s$ procedures)
A#"ions $or Re#ommen&a"ions'
uggestion for design changes$ procedural changes$ or areas for further study (e.g.$ adding a redundant pressure alarm or reersing the sequence of t"o operating steps)
TABLE . Common HAZOP Analysis Pro#ess Parame"ers 9lo"
Time
9requency
2i!ing
ampling
Pressure
'omposition
:iscosity
Addition
0nspection
Temperature
pH
:oltage
eparation
2aintenance
6eel
peed
0nformation
3eaction
'ontrol
5ach guide "ord is combined "ith releant process parameters and applied at each point (study node$ process section$ or operating step) in the process that is being e!amined. The follo"ing is an e!ample of creating deiations using guide "ords and process parameters; )%i&e Wor&s
Parame"er
De*ia"ion
-o
<
9lo"
=
-o 9lo"
2ore
<
Pressure
=
High Pressure
As 8ell As
<
One Phase
=
T"o Phase
Other Than
<
Operation
=
2aintenance
>uide "ords are applied to both general parameters (e.g.$ react$ mi!) and specific parameters (e.g.$ pressure$ temperature). 8ith the general parameters$ it is not unusual to hae more than one deiation from the application of one guide "ord. 9or e!ample$ more reaction could mean either that a reaction ta#es place at a faster rate$ or that a greater quantity of product results. On the other hand$ some combinations of guide "ords and parameter "ill yield no sensible deiation (e.g$ as "ell as "ith pressure). 8ith the specific parameters$ some modification of the guide "ords may be necessary. 0n addition$ analysts often find that some potential deiations are irreleant because of a physical limitation. 9or e!ample$ if temperature parameters are being considered$ the guide "ords more or less may be the only possibilities. The follo"ing are other useful alternatie interpretations of the original guide "ords; ?
Sooner or la"er for /o"0er "0an/ "hen considering time
?
W0ere else for /o"0er "0an/ "hen considering position$ sources$ or destination
?
Hi0er and loer for /more/ and temperature$ or pressure
/less/ "hen considering leels$
8hen dealing "ith a design intention inoling a comple! set of interrelated plant parameters (e.g.$ temperature$ reaction rate$ composition$ and pressure)$ it may be better to apply the "hole sequence of guide "ords to each parameter indiidually than to apply each guide "ord across all of the parameters as a group. Also$ "hen applying the guide "ords to an operating instruction (e.g.$ procedural step)$ it may be more useful to apply the sequence of guide "ords to each "ord or phrase separately$ starting "ith the #ey part that describes the actiity. These parts of the sentence usually are related to some impact on the process parameters. 9or e!ample$ in the procedural step The operator starts flo" A "hen pressure @
is reached$ the guide "ords "ould be applied to; ?
tarts flo" A (no$ more$ less$ etc.)
?
8hen pressure is reached (sooner$ later$ etc.)
The guide "ord%parameter combinations are selected by the HAZOP leader. HAZOP 'onsideration of Pipeline A pipeline for our purposes here is one that 4oins t"o main equipment itemsB for e!ample$ "e might start "ith the line leading from the feed tan# through the feed pump to be the first feed heater. A series of guide "ords are applied$ in turn$ to this line;
None$
? -one
? Part of
? 2ore of
? 2ore than
? 6ess of
? Other than
for e!ample$ means no for"ard flo"$ or reerse flo" "hen there should be for"ard
flo". We ask:
? 'ould there not be flo"C ? 0f so$ ho" could it happenC ? 8hat are the consequences of no flo"C ? Are the consequences hazardous or do they preent efficient operationC ?0f so$ can "e preent no flo" (or protect against the consequences) by changing the design or operating methodC ? 0f so$ does the size of the hazard or problem (that is$ the seerity of the consequence$ times the probability of occurrence) 4ustify the e!tra e!penseC The same questions are then applied to reerse flo" and "e then moe on to the ne!t guide "ords$ more of . 'ould there be more flo" than that designedC 0f so$ ho" could it ariseC And so on. The same questions are as#ed about more pressure and more temperature$ and if they are important$ about other parameters such as more radioactiity or more iscosity. Table , summarizes the meanings of the guide "ords$ "hile 9igure * summarizes the "hole process. In studying a batch plant, one must apply the guide words to the instructions (whether written or on a computer) as well as to the pipelines. For example, if an D
instruction states that metric tone of ! has to be charged to a reactor, the team should consider such de"iations as:
? 1onEt charge A. ? 'harge more A. ? 'harge less A. ? 'harge as "ell as A. ? 'harge part of A (if A is a mi!ture). ? 'harge other than A. ? 3eerse charge A (that is$ can flo" occur from the reactor to the A containerC).