Electricité company with an industrial and commercial
Electricité du Liban (EDL) is a recognized company with an industrial and commercial career. It was founded on July 10, 1964, and it is executed for the generation, transmission, and distribution of electrical energy in Lebanon. Power generation plants in Lebanon are divided into hydraulic and thermal. The electrical power generation and distribution industry has developed during almost exactly one century into its present form. This progress has been driven by economics and technological improvement.
These varied forces have presented generation and distribution systems that are reliable, safe, and environmentally acceptable, suitable for service over the world. Due to the need of extensive electricity in our society, there is an interest in the technology of electric power production and distribution. Every day, the generation of electric power lands more pollution than any other single industry. This pollution is modifying the planet’s climate and ecosystems in ways that will damage generations to come.
Costumers had little choice about their electricity provider, but recently, more states are presenting an opportunity to support cleaner, healthier power supplies. New power plants depending upon state-of-the-art technology generate lower levels of toxic emissions than older plants, even when burning coal or oil, fossil fuels typically counted “dirty.” Moreover, the conventional process of power generation and supply to the customer is lavage in the sense that only about a third of the primary energy fed into the power plant is actually made available to the servant in the form of electricity. A range of technologies can be used to cogenerate electricity and heat such as steam turbines, gas turbines, combined cycle (steam and gas turbines) and Diesel and Otto engines. Three other technologies have recently come into the market, or are likely to be advertised within the next few years: Fuel cells, micro turbines and Stirling engines. In general, for industrial applications, steam turbines are of simpler single casing design and less complex for reliability and cost reasons. A steam turbine is an apparatus that separates thermal energy from pressurized steam and uses it to do mechanical work on a rotating output shaft. The steam turbine turns a generator, to transform the mechanical energy into electrical energy.
Waste heat recovery power systems used for cement kilns work on the Rankine Cycle. This cycle, known as thermodynamic cycle, is essential for traditional thermal power generating stations and holds a heat section (boiler) that turns a liquid working fluid to high-pressure vapor (steam) that is then elongated through a turbogenerator producing power. Exhausted from the turbogenerator, low-pressure vapor is condensed back to a liquid condition, with condensate from the condenser going back to the boiler feed water pump to carry on the process. WHR systems formed of heat exchangers or heat recovery steam generators HRSGs that send heat from the pooped gases to the working fluid inside, turbines, electric generators, condensers, and a working fluid cooling system.Through the efficient implementation of the environmental management system, Holcim seek to diminish the environmental impacts of their operations through managing resources, reducing emission levels and measuring performance. The past three years testified significant reductions in the levels of atmospheric emissions such as dust at stack, fugitive dust and ?CO?_2 as well as improvements in other environmental signals. Environmental investments went beyond compliance with legal demands to rich ambitious internal targets. The energy intensive cement industry meets high and rising energy costs and must encounter requirements for reducing ?CO?_2 emissions.
One remedy for these challenges is to increase energy efficiency by recovering waste heat and converting it to electricity.A waste heat recovery project for electricity generation, a modern solution to the rising costs of fuels was launched in 2011 to boost energy efficiency and reduce emissions. This project will save on the use of fuels, resulting in an improvement in environmental footprint, offering significant potential for “?CO?_2free” power generation and reduction in energy costs. WHR does not require any primary fuel to generate power. The project, with a total investment of 11 M. USD, is expected to be achieved in 2012. The purpose is to generate the same amount of electricity from the power plant, using three generators instead of four. Once completed, it will produce 3 MWh of electricity, reducing overall fuel consumption of the power plant from 225 g/kWh to 198 g/kWh; Thereby, saving 5000 tons of fuel annually.
Therefore, to reduce heat loss, pollution and impact of fuel cost on the electricity and cement production, Holcim wishes that part of the facility needs could be covered by a new Combined Cycle Power Plant (CCPP). The CCPP uses the waste heat released by the existing Diesel Power Plant to generate steam in a heat recovery steam generator (HSRG). The principle behind the installation is the recovery of exhaust gas from three generators, whereby hot steam is used to turn turbines, hence generating electricity and improve cycle efficiency.Established in 1929, Holcim Lebanon is one of the leading cement companies in Lebanon.
The plant and head office are situated on the shore of Chekka bay, and products are distributed to customers all over the country. Holcim Lebanon also operates a white cement plant through its subsidiary in Chekka, Société Libanaise des Ciments Blancs (SLCB), the only producer of white cement in Lebanon. Hence, a full range of cement products is produced to meet the needs of the market as well as special products designed for use in a variety of applications. Moreover, six ready-mix concrete plants in Nahr El Mott, Beirut Harbor, Kfarchima, Chekka, Halba and Tyre are operated under Holcim Béton, along with a grinding station located in Northern Cyprus (BEM). Over the years, Holcim Lebanon has undergone continuous modernizations and operates the largest kiln in the country.
The annual cement production capacity evolved to reach 2.5 million tons currently. The cement plant is certified ISO 9001 for quality management system and ISO 14001 for the environmental management system. Their cement is in compliance with the Lebanese Standard, NL 53:1999. Holcim Lebanon is registered in the Beirut Stock Exchange.
In 2015, LafargeHolcim were created after a global merger completed by Holcim and Lafarge. The new Group creates a combined experience of over 180 years in the cement, concrete and aggregates sectors and includes over 115,000 employees operating in 90 countries all over the world.The required electrical energy for the cement plant at Holcim, connected to the local grid, is today generated by 2 power plants: A Diesel Power Plant providing most of the energy and a Hydro Power Plant.Power generation cost is strongly increasing due to cost of fuel: diesel power plant is generating 90-95 % of the total energy, and production price is mainly due to fuel cost.The captive power plant is composed of 8 diesel-engine generators with nominal capacities varying from 6.
5 to 18.4 MW.In 1948 the power plant was structured with 4 generators of 700 kW each, a gas turbine of 3750 kW and a hydroelectric plant next to the river Joz with 3 turbines of 5500 kW. Kiln number 3 was built-up with a capacity of 300 tons per day in 1949. Kiln number 4 was equipped with a capacity of 480 tons per day in 1951. In 1956 & 1957, capacity of kilns was ameliorated to 900 tons per day.
In 1960s, fundamental facilities were placed like conveyor belts to transport raw materials from the quarry site to the plant, four mills and underground tunnel to transfer materials. In 1968, kiln number 5 capacity was improved to 2000 tons per day. Creation of new facilities raised the capacity of the plant to half a million tons per year.Between 1974 – 1978, the production capacity reached 1.35 million tons per year.
An additional kiln number 6 was picked with a capacity of 2,000 tons per day, in 1978.In 1990s was the modernization of the plant. In 1995, for reducing water used in the plant, the production process changed from wet to dry process, significantly. In 1997, Kiln number 7 was equipped with an annual capacity of 2.5 million tons of cement. All other kilns were locked after 1997.The CCPP considers the use of the waste heat from exhaust gases of engines 6, 7 & 8 (because they are new) to be converted into electricity through steam turbine.
The load on engines 6, 7 & 8 will vary between 70 to 90% according to the plant consumption. The CCPP shall utilize the available waste heat which depends on Diesel power plant operation modes and corresponding operation times. The quantity of waste gas available depends on the utilized fuel and the operating conditions (power output). A steam Rankine Cycle (SRC) is the thermodynamic cycle which is applicable to the WHR power plant on engines 6,7 and 8.The Combined Cycle Power Plant to be installed downstream the existing engines 6, 7 &8 will consist of the following main components and systems:- 3 (one for each engine) waste heat recovery boilers (HRSG) or heat exchangers.
– 1 power generation package (turbine, gear box, generator and auxiliary systems).- 1 water cooled condenser.- Main cooling system for condenser (circulation pumps, piping…)- Condensate system made of condensate pumps, de-aerator and feed water tank, main feed pumps, steam bypass, steam piping, condensate piping and feeding system. – Balance of Plant systems such as: a) Compressed air station b) Water demineralization system for steam cycle c) Chemical dosing system – Control and protection system including instrumentation. – The civil works for foundations, structures and buildings. – Interconnecting ducting, piping and cabling.
The exhaust gases from Diesel engines 6, 7 &8 are the available heat sources for the CCPP. The engine exhaust gas WH exchangers (one for each engine) are installed downstream the silencers. Bypass dampers are installed to cut off the exhaust gas flow to the WH exchanger in case of maintenance. For the limitations in WH exchangers, the Diesel power plant burns heavy fuel oil so that we will ensure to avoid condensation and corrosion in the WH exchangers and in the exhaust ducts and stacks. For this reason, the following SO2 quantities have been measured by Holcim.
A single casing condensing multistage steam turbine will be installed, with bleeding to be used in the de-aerator for the preheating of water entering the exchanger. And considering the availability of water, the CCPP will use the existing salty cooling water sources from the basin.While some waste heat losses from industrial processes are inevitable, facilities can reduce these losses by improving equipment efficiency or installing waste heat recovery technologies.
Waste heat recovery entails capturing and reusing the waste heat in industrial processes for heating or for generating mechanical or electrical work. Heat recovery steam generators HRSGs can run in either the cogeneration mode or the combined-cycle mode. If cogeneration procedure is practiced, steam produced from the HRSG is mainly utilized for process applications, whilst in the combined-cycle mode, power is generated via a steam turbine generator, which it is our case.
The HRSGs consist of four major components: the economizer, evaporator, super heater and water pre-heater (de-aerator).Based on the flow of exhaust gases, HRSGs are categorized into vertical and horizontal types. In horizontal type HRSGs, exhaust gas flows horizontally over vertical tubes whereas in vertical type HRSGs exhaust gas flow vertically over horizontal tubes.- Economizers can be provided to utilize the flue gas heat for pre-heating the boiler feed water before it enters the steam drum or furnace surfaces. Economizer performs a key function in providing high overall boiler thermal efficiency by recovering the low level energy from the flue gas before it is exhausted to the atmosphere. It increases water temperature close to the saturation temperature, known as Approach Temperature. Approach temperature ensures operational flexibility and maximum heat energy absorption efficiency.
– In the evaporation circuit the water is heated to as close to saturation temperature as is possible. This method modificates the water from liquid to vapor or steam. – The major function of super heater is to increase the pressurized water temperature above the steam saturation temperature for use in the steam turbine. Saturated steam is considered as “dry” steam. The Super heater absorbs heat energy from the Diesel engines exhaust gas and transfers this energy to the steam. – An open feed water heater (pre-heater, De-aerator) is a FWH in which a small amount of extraction steam mixes directly with the feed water to raise its temperature. The function of feed water heaters is to use the energy of extraction steam to reduce the addition of external heat by raising the temperature of the feed water before it arrives at the steam generator.
A steam turbine is a mechanical device that converts thermal energy in pressurized steam into useful mechanical work in a process in a closed system known as the Rankine cycle.The condenser is a shell and tube heat exchanger that utilizes copper tubes in which low pressure vapor is cooled and condensed into a saturated liquid. The boiling process or steam generation occurs in evaporator parts. The water temperature rises as heat energy is absorbed by water from the gas stream.
When water attains the boiling point or saturation temperature, some of the water evaporates to steam.In this last section, importance of WHR is stated, and the advantages of the economizer and feed water processes are presented. – Benefits of ‘waste heat recovery’ can be broadly classified in two categories: ? Direct Benefits: Recovery of waste heat has a direct effect on the efficiency of the process. This is reflected by reduction in the utility consumption & costs, and process cost. ? Indirect Benefits: – Reduction in pollution, in equipment sizes and in auxiliary energy consumption.- Economizer reduces operating costs or economizes on fuel by recovering extra energy from the flue gas.
– The feed water reduces the solubility of all dissolved gases and removes it from the feed water. The liberated gases are then vented from the de-aerator.