Transcript KEY CHARACTERISTICS OF A COGEN INVESTMENT
Introduction
Cogeneration is the use of single input of fuel to simultaneously produce useful electricity and heat from the same source . In the production of electricity , heat is normally wasted as exhaust
IF NOT IN USE
.
.
The energy requirements in factory can be obtained through an evaluation of the data recorded in terms of the pattern in electrical and thermal loads . The electrical and thermal loads can vary depending of many changing range .This depends on various factors such as
process changes , or seasonal changes
.The study case is a Cogenplant supplying Steam and Power to a Sugar Milling & Process Factory and Power export to the National grid .In this case the changes depend on the load use of
EXTRACTION LOW PRESSURE STEAM and QUALITY of Fuel
( Bagasse Fibre and % Moisture content)
BAGASSE: Heating Value 7 to 8 mj/kg-Mineral Content 3to4 % Dry basis Moisture Content 45 to 50 % Wet Basis
As the investment was at company level, an evaluation of the company’s requirements was already identified (Case study FUEL steam & power generation co. ltd POWER PLANT No.2) Some of the issues that were considered when developing this particular cogeneration project::
- Macro economic condition and stability of currency in the country.
- Policies of various levels of government and utilities related to industry.
- Types of projects implemented & financial implication.
- Success and failure stories of other developers and company developer(Power Plant No.1
)
- Feasability studies - Investment/Tendering/Contracting
- Construction - Operating
Pre-Investment/ Feasability studies
A step-by-step approach on how to conduct project pre feasibility and feasibility studies were presented .
This part also discussed the environmental impact assessment in relation to the technologies ,environmental issues such as social & community impacts
.
Feasibility study is the crucial stage, which will determine whether cogeneration is viable and which is the best system for the particular application:
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Collection of data and drawing of load profiles for the various energy forms needed: electricity,heat,Steam at various pressure and temperature levels, heat in the form of hot water at various temperatures, cooling requirements, etc. Load profiles vary for typical Days and Nights of the week compared to the weekends,for various months and seasons.
*Collection of information about electricity and fuel tariffs.
* Selection of the number of units and of the capacity of each unit.From the point of view of energy efficiency, the Max cogenerated heat is used, avoiding rejection to the environment.
* Selection of the operational mode and calculation of the energy and economic measures of performance.(
Same as PS 1
)
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A multi-criteria approach was considered.
* Besides the financial evaluations, it was important to assess the effects of projects on the different areas of the concerned environment and population.Priority to obtain EIA Certificate from the required Authority.
Selecting an energy efficient cogeneration system to meet industrial process needs is very important,very often the question is “
Does cogeneration really offer an effective way to keep energy requirements on both power and heat while reducing the energy costs per unit of production?”
In fact,the answer is not simple.The matching process is critical when developing cogeneration to satisfy both heat and power requirements. Optimisation of design is an issue that has to be taken into consideration, on how to meet the needs of the industrial process and should be economically viable within a certain limit.That’s why Evaluation of energy requirements is the first step of the design.
Accurately tracking the system demands was the best result to a better cogeneration implementation rather than other cases.
*Electricity Tracking :
The electricity consumption in kWh was recorded over a 24 hour period on hourly, daily and monthly basics.
Cooling Tracking:
The heat demands in kg of steam or m3 of hot air at different temperature levels were recorded on hourly,daily and monthly bases.
The cooling water Temperature and the ambient Air Temperature or cooled air at different temp,points & levels were recorded on hourly, daily and monthly bases.
The existing load patterns, electrical and thermal, were used to estimate the heat-to power ratio on every period of each day.The maximum and minimum values of heat to-power were recorded.
The heat-to-power ratio and vice versa depends of many factors and must be determined on a case-by-case basis.In Sugar cane industries, for Ex., seasonal effects (such as high electricity demand, low heat utilisation in summer and the reverse in winter) play a major role.
Our cogeneration vary with these two options:
- Operate as an island, and meet both heat and power demands (CROP SEASON ) - Meet the Power demand at all times (INTER CROP)
* Discussions on the issues and options during the investment phase ,Contractual issues , risk mitigation and allocation were emphasised . * Setting up of a simple procedure in tendering for EPC (Engineering/Procurement/Construction) & equipment supply. * Listing and evaluation of the different types of financing alternatives and sources of finance available according to the need of the project was presented. * A brief description of financial packaging and financial clause was also discussed.
The project entered the construction stage when it met all of the necessary financial requirements . On the other hand a technical team also dealed with detailed design, engineering and construction of the cogeneration project.
One of the major concerns related to the investment of energy-related equipment is the choice of technology. The design criteria vary from one fuel to another or can be design to
TO BE RUN ON A COMBINED Fuel
considerations.
basis too. By selecting the appropriate technology, issues related to costs, technical reliability and manufacturer’s capability , and environmental protection was taken into Considerations also included the long-term availability and cost of fuel, the cost of electricity purchased including charges associated with the provision of a back-up supply,and the credit earned for any exported electricity. In addition, service and technical support available from the equipment suppliers, and the proven reliability of particular machines, may have a significant impact on the profitability.
By experience the undermentioned criterias were considered in the selection of the cogeneration technology:
- Quality and completeness of technology information .
All detailed information of technology were considered.Heat-to power ratio, plant efficiency and fuel supply, is of MOST importa nt .
-Heat utilisation .
Heat/steam utilisation is the amount of heat/steam energy used for useful purpose compared to the total energy input into the cogeneration system. Thus, quality and quantity of heat/steam requirement was considered . Normally in terms of heat/steam balance diagram, it was the most efficiency system selection for our process and existed set up.
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- Technology reliability .
The reliability of equipment suppliers & equipment reliability, consultants, operation and maintenance training contractors or institutions, major stakeholders ,etc. required was considered and proved before selection.
(
Site visits/Survey on existing installations/users and survey is VERY IMPORTANT before choice)
-Fuel supply security.
Fuel characteristics, sources, logistics, preparation, handling and short term/long term
Steam generators/boilers are designed to produce steam for process requirements, for process needs with electric power generation, and OR as a matter of sole technology for electric power generation. In this case, the first priority was to ORDER the best design/ the most efficient and reliable boiler at a reasonable cost taking into consideration the characteristics of PS 1.
Boiler design involves the interaction of many variables:
transfe
r.
water-steam circulation, fuel characteristics, firing systems and heat input, and heat
The furnace room is one of the most critical components of a steam generator and must be designed to assure high boiler availability. The furnace configuration and its size are determined by
combustion requirements, fuel characteristics, gas emission standards
temperatures.
and the need to provide a uniform gas flow and temperature entering the convection heat-absorbing surfaces so as to minimize ash deposits and excessive superheating metal
Some factors that were considered when selecting the boiler
: - Fuels, including projected costs and availability - Steam requirements: temperature, rate of delivery, and pressure - Load profile: turndown - Boiler feed water: source and treatment - Space requirements, including fuel storage - Air pollution emissions and regulations - Energy to drive auxiliaries - Required Operating Man power
Steam turbine was the appropriate choice for our installations because :
- Of Existing Power Plant No.1
- The Electrical base load is over 250 kWe.
- There was a high process steam requirement and heat-to-power demand ratio greater than 3:1 - Of the availability of Cheap/low-premium fuel(Bagasse) - The Existing smaller boiler plants were in need of replacement(Elimination of 2 old 22bars boilers)
Sources of cogeneration information, technologies and references were listed.
Details of operations and maintenance of the cogeneration plant. An effective operations and maintenance organization and management significantly influence the profitability of the cogeneration plant,mainly when we produce towards the National grid.Training of Man Power is very important.
Sources of cogeneration information, technologies and references completed as follows:
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Opportunity Study (The company was already the 1 st Mauritius since 1983) IPP in
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Pre-feasibility Study(Students from UNIVERSITY of MAURITIUS)
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Feasibility Study(Done)
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Support study(Done)
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Project) Appraisal(Company Board of Directors)
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Negotiation and contracting( Company Administration)
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Engineering Design Construction (FUEL Staff & Private Company from Mauritius)
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Commissioning and Start-up (Supplier Engineers & Local Staff)
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Efficiency and Reliability Control(Supplier Engineers & Local Staff)
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Operations & Maintenance Management(Training Programme)