PROCESS PLANT ENGINEERING
Adiabatic: a thermodynamic process that takes place without heat transfer to or from an external source. When a fluid is compressed adiabatically, there is an increase in temperature of the fluid. Likewise, adiabatic cooling occurs when the pressure of the fluid is reduced without any heat exchange to the surrounding. Adiabatic expansion of a fluid occurs without any heat transfer with the surroundings. Adiabatic compression is the compression of a gas without any transfer of heat to the surroundings. It results in an increase in the temperature of the gas undergoing compression.
Adsorption: a process in which components in gases, liquids, or dissolved substances are selectively held on the surface of a solid. It is used to remove components that may otherwise be harmful if released into the environment or may cause process difficulties further downstream such causing the poisoning of a catalyst. Adsorption usually takes places in fixed beds.
Algorithm: a mathematical method or operation that follows a scheme of calculations or steps designed to be repeated such that the result from one calculation forms the basis of the next. The stage-by-stage computation of the liquid and vapour flows and compositions in a distillation process is based on a defined algorithm.
Aspect Ratio: the ratio of the height to width or diameter of an item of process plant equipment such as a column or storage tank.
Back Pressure: the resistance to a moving fluid to its direction of flow caused by an obstruction, bend, or friction in a pipe or vessel. It is often used to describe the discharge pressure from a pump or compressor. The term often refers to a pressure greater than atmospheric.
Basic Process Control System (BPCS): A BPCS is a system employed in a process plant that receives inputs from field sensors and process instrumentations, process these information followed by executing a group of actions based on a set of algorithm.
Battery Limits: the geographical perimeter that surrounds a processing area and includes process equipment, piping, and associated buildings and structures of a process plant.
Blast Wave: a pressure pulse moving outwards from the site of an explosion. It can be formed by a detonation, a rapid deflagration, or the sudden failure of a piece of process equipment containing a potential energy source that is released at a high rate. The blast pressure is the side-on overpressure and can have destructive effect on buildings and structures.
Block Flow Diagram: a schematic representation of an entire process or major part of a process in which unit operations are symbolically represented as blocks in which process material collectively enters for processing and products leave the process plant. Unlike a process flow diagram, a block diagram has limited information. No information is provided such a flow compositions or details of process conditions within each unit operation. They are useful at the design stage to present how a complex process fits together.
Boundary Condition: used in solving differential equations that are used to describe natural phenomena such as the movement of mass or flow of heat or fluids; they are used to define the boundary of the region under consideration. The boundary condition or value is required to be specified for a solution to be reached. The boundary condition may be a physical entity, such as the velocity of a fluid at a surface, or the concentration of components at a fluid interface.
Boundary Layer: the region between a surface or wall and a point in a flowing fluid over it where the velocity is at a maximum. Within the region, the movement of the fluid flow is governed by frictional resistance. By convention the edge of this region assumed to lie at a point in the flow that has a velocity equal to 99% of the local mainstream velocity. Within the boundary layer, which is laminar in flow, the transfer of heat and mass across it occurs only by molecular diffusion.
Chartered Engineer: a person who is both academically and professionally qualified in engineering. A chartered engineer has a proven ability to work at a high level without supervision to solve complex engineering problems, develop new or existing technologies through innovation, creativity, and change. He or she may be involved in pioneering or promoting advanced designs and design methods, work on new and more efficient products techniques, marketing and construction concepts, engineering services and management methods. A chartered engineer is also engaged in technical and commercial leadership. The person is entitled to use the post-nominal letters CPEng or CEng after his or her name and will also be member of the institution of engineers.
Chemical Engineering: a branch of engineering that deals with the design, construction, and operation of processes and plant that involve physical, chemical, and biological change for the conversion of raw materials into useful products on an industrial scale. The principal operations include mixing, reaction and separation.
Clean-in-Place (CIP): a fully or partly automated technique used to clean and sanitize closed process equipment after use and before reuse. Used throughout the food and biochemical industries, it avoids the time-consuming process of dismantling equipment and manual cleaning or where cleaning by other means is too difficult due to restricted access. The equipment to be cleaned is equipped with nozzles with supply and return pipes to and from a CIP kitchen. This involves the preparation of the necessary chemicals and wash water and heat exchangers. The cleaning solution is pumped through the equipment often as a spray through the nozzles. A CIP programme typically involves a pre-rinse with water, circulation with a cleaning solution, an intermediate rinse, disinfection and a final rinse with water.
Commissioning: a final and thorough check of an installed process plant or item of equipment to ensure that it is fully operable as intended. All aspects of the process plant or equipment are tested individually and collectively. Prior to commissioning, a site acceptance test is carried out. At the end of the working life of a process, the process plant and its equipment are decommissioned and taken out of service.
Conceptual Process Design: a work activity performed by engineers at an early stage to evaluate in broad terms the technical feasibility of new and existing processes, as well as process redesigns based on existing feed materials. The work activity examines the thermodynamic feasibility of process routes and the process variables required and assess the broad issues of chemical and process production, which includes information on process costs and material selection. The use of heuristics and process simulation using computers are useful tools to provide rapid information before committing resources to a more detailed design using tools such as computer-aided-design (CAD).
Design Basis: a document that is prepared prior to the design and development of a process plant. It includes the rationale for the design, and includes assumptions and decisions on the options identified for the design as well as the codes, standards, and regulations required in the design. The document is used as the basis for the design, development and construction of the process.
Distributed Control System (DCS): a general name for control systems that are used to control processes characterised by multiple controllers distributed throughout the process and connected by networks for the purpose of communication and monitoring data. They are connected to sensors and valve actuators and can use proportional, integral and derivative control, as well as perform neural network and fuzzy-logic control and be connected to a human machine interface (HMI).
Duty: the power requirement for a machine or item of process plant such as a heat exchanger. The duty of a heat exchanger is dependent on the amount of liquid to be heated, cooled, vaporised or condensed. The duty of a centrifugal pump is dependent on the flow delivered and pressure generated. The SI units for duty are watts or more usually kW or MW.
Emergency shutdown (ESD): the rapid and safe shutdown of a process plant or item of equipment due to a serious deviation in plant operation. Critical valves shut to isolate sections of the process. Other valves may be opened to depressurise vessels or rapidly discharge contents of reactors to quench tanks. Emergency shutdowns may occur due to changes in process plant conditions causing unstable or unsafe operating conditions, a failure in the control system, operator intervention causing unsafe conditions, process plant and pipe failure or some other external event such as electrical storm.
EPC(M): engineering, procurement and construction (construction management)
Feedback Control: a closed-loop method of controlling a plant process in which information about the controlled variable is fed back to the input and compared against a desired value. The difference between the two signals is called the error or deviation. The feedback can be accomplished by a human operator as in manual control or by the use of instruments as in automatic control.
Feedforward Control: a method of process control in which a disturbance is detected before it enters the system for which the controller calculates the required counter-acting disturbance. Process disturbances are measured and compensated for without waiting for a change in the controlled variable to indicate that a disturbance has occurred. Feedforward control is useful where the final controlled variable is not able to be measured. The necessary equations are solved by the controller relating all the process variables, such as steam flow, liquid output temperature etc which are usually designated as the process model. Perfect models and controllers are rare so a combination of feedback and feedforward control is more desirable.
Front End Engineering Design (FEED): is a basic engineering which comes after the Conceptual design or Feasibility study. The FEED design focuses on the technical requirements as well as rough investment cost for the project. It can be divided into separate packages covering various components of the project, can be used as the basis for bidding the Execution Phase Contracts (EPC, EPCM, etc) and is used as the design basis.
HAZOP: an abbreviation for hazard and operability, it is a systematic and structured hazard evaluation technique used to identify the potential failures of process plant or equipment which may otherwise become hazards and present potential operating problems. The aim is to eliminate or minimise the probability of an incident from occurring and the severity of consequence arising from that incident. It uses a multidisciplinary team-based approach to consider what can go wrong, the causes, consequences, frequency of occurrence, measures for prevention and justification of the associated costs of prevention.
HYSYS: An abbreviation for Hyprotech Systems, is a process-modelling software, capable of steady-state and dynamic simulations. It was developed by AspenTech and usually used by chemical engineers to mathematically model chemical processes, from unit operations to full chemical plants and refineries. HYSYS is able to perform many of the core calculations of chemical engineering, including those concerned with mass balance, energy balance, VLE, heat transfer, mass transfer, chemical kinetics, fractionation and pressure drop.
Inherently Safe: a plant process or plant system that is able to operate safely without the need for external or auxiliary support. For example, a cooling water system to a plant process that uses heat exchangers of a sufficient duty and that are fed under gravity to ensure removal of heat is inherently safe.
Law of Conservation: states that the total quantity of something or energy remains unchanged within a system although there may be changes occurring within the system such as chemical reactions, changes of states, and other physical, chemical and biochemical changes. This law states that the total amount of material or energy within the system boundary neither increases nor decreases. This law forms the basis of material and energy balance for a process.
PID Control: the modes of control employed to control plant processes or part of a plant process. The three basic modes of control are proportional control, integral control and derivative control.
Piping & Instrumentation Diagram (P&ID): a schematic representation of the interconnecting pipelines and control systems for a plant process or part of a plant process. Using a standard set of symbols for plant process equipment and controllers, it includes the layout of branches, reducers, valves, equipment, instrumentation and control interlocks. They also include process equipment names and numbers; process piping including sizes and identification’ valves and their identification’ flow directions, instrumentation and designations; vents, drains, sampling lines and flush lines. P&IDs are used to operate the process system as well as being used in plant maintenance and process modifications. At the design stage, they are useful in carrying out safety and operations investigation such HAZOP. Our engineering consultants is one of the very few chemical plant design firms that incorporate performance-based engineering with prescriptive engineering principles.
Plant: major equipment and machinery used in industrial processes. A process plant is the entire industrial process or factory in which raw materials are converted to products through chemical, physical or biochemical transformation.
Plant Layout Study: an analysis of the different possible physical configurations for an industrial process plant. Due to the complexity of modern plants and manufacturing facilities that involve complex operations, the study typically involves the physical space and proximity of vessels and equipment, materials handling, piping and auxiliary equipment, utilities and services, communications systems, emergency systems, structural and architectural considerations and general site work.
Safety Instrumented System (SIS): An SIS is system where if the basic process control system (BPCS) fails and the operator fails to respond in a timely manner or the action taken does not mitigate the issue, the SIS is automatically activated and execute direct drastic actions such as shutting down the plant.
Upstream: a stream of material for processing that has not yet entered the process for chemical transformation in reactors etc. The stream of material that has already been transformed is called Downstream.
Yield: the amount of a product that is recovered from a process or chemical reaction. It is usually expressed as a fraction or a percentage based on the raw materials used or as a ratio of the final product to the starting materials without considering any side reactions.
PROCESS PLANT SAFETY
Our plant safety consultants provide plant safety review by adopting good engineering practices, using various engineering techniques and simulation technologies. Despite the complexity of safety reviews, in general our safety reviews can be broken down into five major steps, namely:
This step involves reviewing the plant designs. Information required to commence this step includes a detailed process descriptions accompanied by process flow diagram (PFD) that contains major equipment, pipes, critical control and mass & energy balance. We also require piping and instrumentation diagrams (P&IDs) that contains all of the equipment, pipes, valves, instrumentation & controls. These P&IDs should be accompanied by functional specifications, safety interlock tables and should exhibit the layers of protection, eg HAZOP, LOPA included in the design. We will also review engineering calculations, datasheets & specifications to ensure these are adequate and appropriate for the intended operations. Finally, we will need to review the plant layout to determine how the equipment will be clustered, the relevant distant employed, the height of equipment and locations of safety equipment. With these information, we will review and benchmark against industry standard, our in-house design checklist and audit the design against relevant standards, regulations and/or government requirements.
Chemical Exposure Index
The chemical exposure index (CEI) was developed by The Dow Chemical Company, used to identify and rank the relative acute health hazards associated with potential chemical releases and its impact to the people in neighbouring plants or communities. This CEI system will provide a method of ranking one hazard relative to another and it is not intended to define a particular design as safe or unsafe. This CEI method is employed for conducting an initial process hazard analysis (PHA), in the distribution ranking index (DRI) calculations, to provide opportunity to make recommendations for eliminating, reducing or mitigating releases and in emergency response planning. The CEI is calculated from five factors: a measure of toxicity; the quantity of volatile material available for a release; the distance to each area of concern; the molecular weight of the material being evaluated; and process variables that can affect the conditions of a release such as temperature, pressure, and reactivity. Hence, we will require chemical and physical properties of all chemicals used in the plant of interest.
Standard Operating Procedures
In this step, we review the standard operating procedures (SOPs), including startup, shutdown, normal, and emergency procedures. The operating procedures should be clear, specific and highlight the limitations of the process, such as temperature, pressure and give the consequences when such limitations are exceeded. In this review, we look for areas such as vague instructions that may result in human errors. We will also select random operators and assess the operator’s ability in executing SOPs. Training records that show operators being equipped with the knowledge to perform risky tasks will also be reviewed. Lastly, we also look at those tasks that should have been incorporated in the design or automated from the outset instead of relying on human actions.
For plant already in operation, we will review accident investigations of previous and relevant incidents that are shared throughout the company and between companies. The purpose is to characterise and understand the weakness of the plant. Apart from review the data stored in either SCADA/PLC or DCS systems, we will also perform statistical process control (SPC) analysis on the plants past performances. Too often, plants simply rely on control system informing when the process variables hit a limit which then triggers actions. Unfortunately, most of such a method devoted far too little attention to variability reduction. A plant in which the process is not stable or has low process capability index is unpredictable and may be unsafe. If the process is centred and has low standard deviation, it will operates within upper and lower limits all the time until a disturbance occurs. And when this occurs, SPC will detect so much earlier before any of the limits are breached giving the control system and/or operators more time to address to the disturbance.
Hazard Identification & Mitigation
In some cases if warranted, in addition to employing the steps outlined above, we may employ computational fluid dynamics (CFD), finite element analysis (FEA) or fluid structural interactions (FSI) simulation technologies. The use of such simulation technologies help to pin-point where the issues are and may further reveal hidden issues. Once we have identified the hazards present in the plant of interest we will develop appropriate recommendations to improve the design and operating procedures to eliminate hazards and prevent accidents. As a plant safety consultant, we will also develop and review the management system to ensure that all of the safety review recommendations are implemented and documented before startup or modifications. Finally, whilst there are several firms offering plant safety consulting services, we differentiate ourselves from other plant safety consultants in the way we approach a problem. Our standard approach involves safety analysis that goes beyond simply adopting rule-of-thumb guidelines. Whilst rule-of-thumb provides a starting point for most plant safety reviews, in some cases, it may lead to overcompensation. In a nutshell, our conventional plant safety review services are supported by in-house advanced engineering technologies to ensure effective & efficient solutions.
Blast Wave: When an explosive charge is detonated in air, the detonation shock front travels away from the charge faster than the expanding gaseous products. The air surrounding the charge is first heated by the passage of the shock wave and is then immediately pushed outwards by the expanding hot gases. After a short distance of travel a new shock front is formed in the air, which has a lower peak pressure and initial velocity than the shock wave but a longer profile. It has a zone of rarefied air immediately behind the high-pressure area. This wave is called the blast wave.
Critical infrastructure: physical facilities, supply chains, information technologies and communication networks which, if destroyed, rendered unavailable for an extended period, will affect the social or economic well-being of a nation or affect a government's ability to conduct national defence and ensure national security.
Crowded Places: crowded places are locations or environments which are easily accessible by large numbers of people on a predictable basis. These include, but are not limited to, sports stadium, transport hubs, shopping centres, pubs, clubs, places of worship, tourist attractions, movie theatres, and civic spaces. Crowded places do not have to be buildings and can include open spaces such as parks and pedestrian malls. A crowded place will not necessarily be crowded at all times: crowd densities may vary between day and night, by season, and may be temporary, as in the case of sporting events or open air festivals
Emergency management: the plans, structures and arrangements that are established to bring together government agencies, voluntary groups and private organisations in a coordinated way to deal with emergency needs, including prevention, response and recovery.
Evacuation: the process of relocating people from dangerous or potentially dangerous areas to safer areas. The purpose of an evacuation is to use distance to separate people from the danger created by the emergency.
Home Made Explosives (HMEs): non-standard explosive mixtures/compounds that have been made or synthesised from readily available ingredients. Explosives remain a favoured terrorist weapon globally. Terrorists favour explosives because of their proven ability to inflict mass casualties, destroy property, cause fear and disruption, and attract media attention. Explosives are generally within the financial and technical capabilities of terrorists
Improvised Explosive Device (IED): a device made or placed in an improvised way that incorporates destructive, lethal, noxious, pyrotechnic or incendiary chemicals and is designed to destroy, incapacitate, harass or distract. IEDs can be assembled with relative ease and used remotely.
Mitigation: measures taken before, during, or after an event to decrease or eliminate its impact on people, property or a location.
Mixed-mode attack: an attack that uses a combination of different weapons, such as a fire and an IED, at single or multiple locations.
Person Borne Improvised Explosive Device (PBIED): an improvised explosive device worn, carried or housed by a person, either willingly or unwillingly.
Preventing Progressive Collapse: preventing progressive collapse is an important part of minimising the structural effects of a blast. A building undergoes progressive collapse when a primary structural element fails, resulting in the failure of adjoining structural elements, which in turn causes further structural failure.
Stand-Off Distant: a proven approach to reducing the threat and impact of an explosive blast is to create a ‘stand-off distance’ between the asset being protected and the area where an IED could be placed. Every metre of stand-off counts in mitigating the effects of a blast.
Situational awareness: the ability to quickly recognise and interpret an event, make sound decisions based on those interpretations, and establish early, effective and continuous lines of communication between the incident site and the controlling agency in order to provide ongoing accurate information to the responders.
Terrorist act: an act or threat committed with the intention of advancing a political, ideological or religious cause, and which is intended to coerce or intimidate a government, or sections of the public, which causes serious physical harm or death to a person, endangers a person’s life, causes serious damage to property, creates a serious risk to the health and safety of the public, or seriously interferes with, disrupts, or destroys, an electronic system.
Terrorist propaganda continues to encourage individuals, particularly those based in Western countries, to conduct attacks at home. Terrorist propaganda can provide practical, easy-to- follow advice on how to prepare for an IED attack – including how homemade explosives can be manufactured from readily available materials. These instructional guides have been linked to a number of terrorist attacks and disrupted plots globally.
Vehicle Borne Improvised Explosive Device (VBIED): an improvised explosive device delivered by or concealed in a vehicle.
AUSTRALIA SINGAPORE ASIA PACIFIC REGION
DEFENCE SYSTEMS DESIGN
We provide defence systems design services for air, naval and land systems. Our defence systems engineering consultants experience includes:
- Independent third-party engineeering evaluation for air, land and naval defence systems
- Aerostructures conceptual design and analysis
- Aircraft performance modelling and simulation analysis
- Naval ship hull form design and minimisation of its drag coefficient to increase its efficiency
- Naval systems hydrodynamics modelling and simulation
- Naval propulsion systems performance review
- Submarine propellar noise signature and degree of cavitation assessment
- Design of an armoured vehicle and assessment of its resilience against blast attacks
- Determination of missiles drag coefficient
- Independent review of the effectiveness of weapons against structures
- Assessment of advanced composite materials suitability for service
- Design and optimisation of munition plants
We provide professional engineering services to industries such as the building & environment, chemical & petrochemical, critical infrastructure, food & beverage, renewable energy and water & wastewater. We differentiate ourselves in the way we approach a problem. Our standard approach involves in-depth analysis that goes beyond simply adopting rule-of-thumb guidelines. Whilst rule-of-thumb provides a starting point for most design works, it has the tendency to overdesign which eventually leads to higher overall fabrication and project costs. In a nutshell, our engineering consultants are supported by in-house simulation technologies to ensure effective & efficient deliverables. We provide services to clients based in Australia, Singapore, Indonesia, Malaysia and our scope of engineering services are:
- Plant Engineering Design
- Infrastructure Protection Design
- Building Services Design
- Defence Systems Design
INFRASTRUCTURE PROTECTION DESIGN
The protection of crowds, public spaces, sensitive buildings and critical infrastructure is a key concern worldwide, with the threat of terrorism ever present. We provide infrastructure protection design services to defend critical infrastructure and most importantly human lives from being attack by extreme loading. The scope of work in which our security & blast consultants operate include:
- Threat, consequence, vulnerability assessment
- Quantitative risk assessment which considers site, architectural and structural resilience of assets
- Blast and fragment effects analysis supported by in-house blast effects analysis
- Structural resilience study including an in-depth analysis of material and structural behaviour
- Predictions on how building structures respond to extreme loading
- Providing customised mitigation measures and recommendations to mitigate risks
- Development of a comprehensive security and blast protection plan
- Cost and benefit study of each option presented by our engineering consultants
- Design based on US Department of Homeland Security (FEMA) and Australia/NZ Counter-Terrorism
Committee (ANZCTC) guidelines
BUILDING SERVICES DESIGN
Our building services engineering consultants provide performance-based engineering design services and indepedent assessment of building designs to attain optimal integrated building systems incorporating environmental control and safety provisions for the comfort and wellbeing of the occupants. The scope of work in which our chartered professional engineers operate include:
- Mechanical services: air condition, mechanical cooling, heating, humidity & ventilation AS 1668.2
- Hydraulic services: sanitary plumbing & drainage, potable hot & cold water, recycled water, water
- Environmental sustainable design: energy modelling, thermal comfort analysis, natural ventilation
study, solar & glare analysis
- Environmental impact: removing particulates & contaminants, diluting gaseous contaminants,
pollutants emission study
- Air movement: circulating and mixing air for proper ventilation and thermal energy transfer
- Fire Engineering: smoke and hazard management, emergency egress study
- Wind effects and wind loads on buiding structures
PLANT ENGINEERING DESIGN
As a process plant design firm, we provide performance-based multidisciplinary plant design services across many industries particularly in the functional areas of:
- Front-end engineering design (FEED) and detailed engineering design for construction
- Capability includes designing plants that process materials in solid, liquid and/or gas phases
- Design of integrated control and safety system (ICSS) that consists of BPCS + alarms + SIS
- Experienced in designing plants as per regulatory requirements, standards and design codes
- Distributed control system (DCS) or modular programmable logic controller (PLC) system
- Process dynamic system modelling and simulation using ASPEN PLUS or ASPEN HYSYS
- Hydraulic calculations, sizing of PRVs and studies of complex piping network
- Process flow diagrams (PFDs) and piping & instrumentation diagrams (P&IDs)
- Mechanical engineering design supported by 2D drafting and 3D geometrical modelling
- Procurement, inspection and receiving of equipment on behalf of clients
- Plant construction management to ensure the plant is constructed as per design intention
- Commissioning support and process plant or chemical plant performance optimisation