Saudi Arabia has been increasing its cement production capacity as it continues its infrastructure development. In many of these cement factories, it has called for increased generating capacity. One example of such an expansion is the Bisha power plant extension where Wärtsilä has installed a new diesel engine to the existing 40 MW plant.
Khalid Abuzahra, Wärtsilä Power Contracting Company, Jeddah, Saudi Arabia,
Pieter Mulder, Wärtsilä Italia S.p.A., Trieste, Italy.
As the government in Saudi Arabia continues to invest heavily into the country’s infrastructure development, the demand for cement is increasing progressively year by year. This infrastructure development comprises many significant construction projects including new roads, schools, hospitals and other public buildings.
Subsequently, Saudi Arabia’s cement industry is now continually increasing its cement producing capacity, to meet the growing need on the market. This has increased the need for power at the cement plants in the Kingdom. To help meet the need for power, the Finnish power company Wärtsilä has been awarded several power plant contracts from cement companies in Saudi Arabia during 2005.
One example of such a cement company is Southern Province Cement Co (SPCC), which owns two cement plants in Saudi Arabia. One plant is near the town of Ahad Al-Masarha, about 70 km from the city of Jazan and the other is about 60 km southwest of the city of Bisha. The Jazan plant has two production lines with a combined annual output of 2.3 million tonnes of cement clinker, while the Bisha plant has a single line producing 1.8 million tons of clinker a year. As the company’s two cement plants have grown considerably in recent years so has their demand for energy.
View of the employees’ residences and mosque
This rigorous growth has meant that SPCC has had to extend Bisha’s original power plant to meet the plant’s increased power needs. For the power plant extension, the Finnish company Wärtsilä was chosen to deliver a Wärtsilä 18V38B generating set. The complete power plant extension was supplied on a turnkey basis which included the civil works and ancillary systems for cooling, fuel handling, exhaust stacks, electrical switchgear and all related control systems. The turnkey project also included electrical and mechanical training at the plant.
Bisha’s power needs
The new generating unit at Bisha runs in parallel with the existing 40 MW power plant which was built in 1996-97. The power plant extension was designed to operate on crude oil and was assembled in Wärtsilä’s state-of-the-art assembly plant in Trieste, Italy. The power plant extension was commissioned and handed over in December 2004 and provides an additional power capacity of 9.6 MW to meet the plant’s growth in power demand. To date the new generating unit has clocked 5950 hours running on crude oil.
It was decided that the new power plant extension should run on crude oil as the existing power plant’s turbines operate on crude oil. In this way SPCC is able to utilize common fuel storage tanks for the existing turbines and the power plant extension. The existing 40 MW power plant at the Bisha cement works consists of four ABB Stahl gas turbines running on crude oil. The choice of a diesel engine was favoured over the gas turbine due to its higher efficiency which leads to lower cost for the produced kWh.
Burning crude oil
Using crude oil as a fuel in power plants does not differ that much from using HFO (heavy fuel oil) in terms of heat rate and emissions. However, the main difference and the ensuing dangers that are experienced with crude oil burning is that it contains flammable gases. These flammable gases can potentially escape from each connection in the fuel piping system. So when crude oil is used safety precautions must be taken regarding the containment of flammable gases and all sources for ignition sparking have to be identified and avoided.
For example, in the case where a diesel engine is driving a crude oil pump, the pump itself is considered as a potential source of hazards. Depending on the size of the perceived risk, the area is classified in different zones with each of the zones requiring special electrical equipment. In the case of the Bisha power plant the diesel engine drives an alternator, this combination is regarded as a low risk area. Nevertheless, several counter-measures are taken on the engine to avoid hazardous gases leaking from the fuel system.
An illustration of the counter measures taken is the closed space around the fuel pump compartment on the engine known as the “hot-box” which must be well ventilated at all times. Additionally, the flanges in the fuel piping outside the hot-box are covered and ventilated as well. From these parts an extraction pipe is connected to the outer wall of the power plant.
A ventilation fan is located at the end of this extraction piping, outside the engine room. The ventilation causes a vacuum in the hot-box and piping covers. The air flows from outside the engine (from the engine room) through normal clearances existing in the hot-box and covering system and transports possible flammable vapours away from the engine. A gas detector in the extraction pipe detects the possible presence of gases.
Furthermore the specification of the electrical motor of the turning gear and the switches in the fuel leakage detection system are upgraded to so-called “ex-proof” (explosion proof) level, devices that do not create any sparks to the open-air. Fuel oil auxiliaries were designed for crude oil motors, electrical heaters were Eexd II (explosion protection) classified. Special pumps were used with magnetic coupling for fuel oil system.
Other areas for special risk assessment include the transfer pump unit, the feeder unit, the booster unit, the HFO separator, the fuel oil unit and the ventilation unit. There were no changes from other standard power plant systems such as the cooling water system, lube oil system and the compressed air system.
Additionally, the separator unit that Wärtsilä supplied for the Bisha plant has a nitrogen generation system for blanketing the separator assembly. This nitrogen gas replaces atmospheric air inside the separator for safety protection. Also, the buildings where the fuel handling equipment is located must have effective ventilation systems in place to extract the flammable gases to the outside of the building.
Plant extension contracts
Another company that has reacted to the increased demand in cement, is Riyadh Cement Company (RCC). Wärtsilä was awarded a contract to deliver a 45 MW power plant to Riyadh Cement Company in June 2005, and the plant will be fully operational during the first half of 2007.
Riyadh Cement Company (RCC) is one of the first companies to make a decision to set up a cement plant of a capacity of 5000 tons per day. The cement plant will be located approximately 75 km southwest of Riyadh. The engineering, procurement and construction (EPC) contract features six Wärtsilä 20V32 generating sets which will burn heavy fuel oil.
The Bisha power plant extension adds 9.6 MW to the existing 40 MW plant
The 20-cylinder Wärtsilä 32 engines were chosen because they meet the customer’s requirements at the high ambient temperature of 50°C and the plant’s high altitude (835 m above sea level). Wärtsilä’s ability to operate reliably under such conditions is well established in the market.
Wärtsilä’s presence in the local market has played an important role in receiving these new orders for cement plants in Saudi Arabia. The company’s engines have gained a good reputation for reliability and are well known for their cost effective lifecycle operating costs.
Additionally, Wärtsilä’s local operations have become well renowned due to the effective after-sales support services provided by the company’s regional office based in Jeddah. In this region, a positive local reputation is a valuable commodity when tendering for new power plant contracts.
Growth in Saudi Arabia
The boom in Saudi Arabia’s cement industry is being created by many contributing factors, not just the rapid growth in its infrastructure.
For instance earlier in 2005, the government pumped some US$2.4 billion into the Real Estate Development Fund (REDF) and the Saudi Credit Bank (SCB). This high level of funding has enabled the REDF and the SCB to lend money to the public to allow them to build and buy their own homes.
The country has also witnessed a huge increase in the value of construction contract awards since the start of 2005 corresponding to the same period last year. In addition, the government has increased salaries of civil servants, including the military, by 15 per cent.
This inward investment into Saudi Arabia has created a high level of confidence among the population and businesses in their country’s economy. This factor has encouraged the private sector to invest in their country instead of looking to foreign markets.