Energy saving opportunities at Twiga chemical industries Limited
This study was to identify the energy usage at Twiga Chemical Industries Limited (TCIL) and analyze the pattern of consumption with respect to production. The other objective was to identify and recommend energy conservation opportunities that can be instituted by TCIL. The sources of energy are electricity, heavy fuel oil (HFO) and diesel in the ratio in percentage of76:15:9 respectively. The annual energy consumption was 1.87 TJ - for 2008, 1.7 TJ - for 2009, 1.71 TJ - for 2010 and 1.75 TJ - for 2011. The average was 1.76 TJ annually. The average production was 262,222 kg for 2008,245,902 kg for 2009,271,920 kg for 2010 and 313,359 kg for 2011. The energy intensities achieved were; 643 KJ/kg for 2008, 589 KJ/kg for 2009, 532 KJ/kg for 2010 and 472 KJ/kg for 2011. The analysis indicates the energy intensity was reducing in the subsequent years. This reflects improved efficiency by TCIL and indicates a higher production demand gives lower energy intensity. This shows it is more costly for low demands of products. However, it was noted that the energy consumption for auxiliary supplies, lighting and security was 109 GJ, composed of89.7 GJ -electrical, 460.7litres ofHFO and 90.6litres of diesel used on monthly basis, which is not directly related to the production. Reduction of this consumption will result in energy saving by the company. The cost of the energy due to the three sources is Kshs.573,702.00 monthly. Observations and measurements were made of production processes and related energy distribution. The following opportunities were identified and analyzed for energy savings: • TCIL should consider migration of tariff from Cl1 to Cl2 which could realize a cost saving ofKshs.61,600.00, monthly, due to reduced kVA demand and kWh costs. • The pf should be above the required level of 0.9, below which the company is surcharged. TCIL was surcharged Kshs.730,622.00 in November 2009 - March 2010 and this was extra cost on energy. The pfwas corrected at a cost of Kshs.345,000.00 with expected payback period of 2 months. • The peak demand to be reduced by improving starting methods for all motors and improving the efficiencies. Change of operation for the Mineral section to operate at night will reduce the peak demand to approximately 121 kVA, from 260 KVA peak, monthly. • The light fittings should utilize electronic ballast for starting of fluorescent tubes; this will further improve on energy saving, at approximately 266 kWh, monthly. • The steam distribution system requires improved maintenance in order to achieve energy saving from exposed steam distribution pipes. Energy due to exposed pipes is approximately equivalent to 3.1 litres ofHFO daily or monthly cost ofKshs.6,985.00. The potential energy saving for the identified opportunities is Kshs.1,127,663.00 and the capital investment to achieve this is Kshs.6,083,400.00, a simple payback period of 5.4 years.