Benefits

	Total energy savings of 57,300 Giga Joules/annum from the new furnace and 2,800 Giga Joules/annum from improvements in two annealing lehrs
	Savings in fuel oil cost of more than 33 percent from heat recovery system for the glass furnace
	Reduction in water consumption by 25 cubic metres per day through recycling
	Total investment of RM7.5 million and annual savings of RM 1.8 million

Summary

Investing more than RM7 million, JG Containers (M) Sdn Bhd (JGC) is one of the leading factories to have implemented energy efficiency (EE) projects. This glass container manufacturer undertook a series of low-cost and high-cost EE improvement measures in an immediate response to the recommendations from the energy audit carried out by the Malaysian Industrial Energy Efficiency Improvement Project (MIEEIP) team at its facility.

Two years since the audits in August 2001, the factory has rebuilt its furnace with a better control and heat recovery system, resulting in a reduction of fuel consumption by 33 percent, or 57,300 Giga Joules (GJ) per annum, and a significant improvement in the quality of glass.

The modification of the operation of the annealing lehrs, a process unique to the glass industry, brought about further annual savings of RM120,000. One lehr, powered by electricity was modified while another similar one was replaced with a natural gas powered lehr.

Measures were also introduced to recycle water, which brought about further savings of RM17,500 per annum.


PLANT OVERVIEW

JG Containers (M) Sdn Bhd, a medium-sized glass container manufacturing company with a workforce of 300 employees, is one of the 48 factories audited by the MIEEIP. JGC commenced its operations in Malaysia 31 years ago and its manufacturing capacity of glass containers is about 120 tonnes per day. The annual turnover for the year 2000 was RM 24 million with different forms of energy costs representing 20 percent of the total turnover.

PROJECT OVERVIEW

Furnace

The glass furnace at JGC experienced high losses because of poor heat recovery from the exhaust and losses from the side walls of the furnace.

The fuel consumption of a furnace depends on three factors:
1. Design and construction;
2. control of the furnace operation (percentage of cullets, excess air etc.); and
3. ageing (adequacy of maintenance as it ages).

The main design criteria are the insulation of the outside walls, and preheating temperature of the combustion air using heat recovery from the exhaust gases. In addition, the loss of heat to exhaust must be kept at a minimum by excess air control. The old furnace at JGC lacked the control systems resulting in higher losses. Besides, the surface heat losses were also high due to the poor technology available back in 1992 to improve the insulation of the surfaces.

The MIEEIP audit report was an eye opener to JGC as the audit compared the Specific Energy Consumption (SEC) in JGC against that for the US, UK, Thailand and Germany. These figures were used as the benchmark to meet, while the JGC management negotiated with suppliers for the furnace rebuilding and renovation in the year 2002. At that time, the SEC of melted glass at JGC was 7.08 GJ / tonne for the old furnace. JGC then adopted the latest advanced crown system for the furnace crown to reduce the heat losses.

Lehr

The annealing of glass, which is the slow cooling to minimise the appearance of stress defects, is an important step in the production of all glass. It is one of the more energy-intensive processes, and the energy audits conducted at JGC revealed high levels of losses whereby the SEC was as high as 0.13 GJ/ tonne of heat consumption at the annealing lehrs.

Recycling of water

The factory consumes about 100 cubic metres of water daily as drinking water; service water for cooling purposes; and to clean the cullets. About 25 cubic metres are used daily for washing the cullets alone and discharged into the drain. The construction of a new filtration system enabled the factory to recycle the water, thus saving 25 cubic metres daily.

Project Implementation and Results

The glass furnace was rebuilt with a better control and heat recovery system from M/S Asahi Glass Japan in October 2002, resulting in an increase in output from 90 tonnes per day (TPD) to 120 TPD of melted glass. The total investment for the whole project was RM7 million with a simple payback period of about four years. For this process, the SEC reduced to 4.94 GJ / tonne of melted glass from the initial 7.08 GJ / tonne.

Following the audit recommendations, JGC immediately reconditioned one of the annealing lehrs at a cost of RM50,000, which resulted in energy savings of 750 kWH per day. The annual costs savings is approximately RM57,000, making the project attractive with a simple payback period of less than one year. The production too increased substantially by reconditioning the annealing lehr. The SEC before and after the reconditioning project are 0.13 GJ / tonne and 0.075 GJ / tonne of glass, which is equivalent to energy efficiency improvement of about 42 percent.


One of the old annealing lehrs was replaced with a new energy efficient LPG / NG-fired lehr at a cost of RM 400,000 in November 2002. This resulted in net savings of RM62,000 per annum in energy cost, giving a simple payback period of 6.5 years. Production increased by about 50 percent. The SEC reduced to 0.042 GJ / tonne from the previous figure of 0.13 GJ / tonne. The new lehr shows a more dramatic energy efficiency improvement of about 67 percent.

These measures have also substantially reduced the CO2 emissions.

In order to recycle the water, a simple tank (size: 6m x 2m x 2m) was installed with a filter to remove the sediment and grit before water is recycled for cullet washing. The cost of the installation was RM18,000, and the savings achieved is RM 17,000 per annum.

Energy Saving Measure	Investment (RM)	Energy Savings (%)	Simple Payback Period (yr)
Rebuilding furnace with control systems	7,000,000	33	4
Modification of oneannealing lehr	50,000	42	<1
Natural gas-poweredlehr	400,000	67	6.5
Water recycling (cost saving measure)	18,000	25	1

Table 1: Summary of energy saving measures

Specific energy consumption

The total fuel and energy consumption of JGC was analysed for the year 2000, the first six months of 2001 and for the first two months of 2003 according to “good glassware and melted glass”. “Good glassware” refers to the net products or packaged goods while melted glass refers to the gross glass pull drawn from the furnace. With the energy saving measures, the SEC for both the good glassware and melted glass reduced from 13.4 GJ/t and 7.08 GJ/t at the start of the energy audit exercise to 9.96 GJ/t and 4.94 GJ/t respectively.

	SEC (GJ/tonnes)
Energy Saving Measure	Before	After
Annealing Lehr (modification)	0.13	0.075
Annealing Lehr (Replaced with natural gas fired Lehr)	0.13	0.042
Glass furnace (Rebuilt with effective controls)	7.08	4.94

Energy Conservation Projects Under Consideration

JGC is fully committed to energy conservation and is considering other EE improvement projects for implementation. The proposed projects mainly involve fuel switching to optimise on the economic, technical and environmental benefits of natural gas. This will include the LPG fired equipment for the remaining electrical annealing lehr and glass melting furnace. The use of natural gas will result in energy cost savings, improve the processes, increase productivity and improve emission norms.

In addition, JGC is keen on the segregation of compressed air supply systems to meet actual requirements, and to replace one low pressure compressor with a high efficiency compressor. The plant requires low pressure and high pressure air for forming the bottles. The factory’s air compressors are now operating at a higher pressure, which is then throttled using pressure regulatorsto reduce the air pressure.The saving expected from the segregation of compressed air requirement and by installing a low pressure air compressor is about RM50,000 per annum with an investment of RM120,000.