Caterpillar Inc.: From Waste to energy: a more effective and emission-reducing way

Company Profile
Over the nine decades, Caterpillar Inc. has made strenuous efforts to promote sustainable development and practice it across all the continents. Caterpillar helps its clients to build infrastructure and explore natural resources. Caterpillar is also the international leading company in construction engineering, mining equipment, diesel and natural gas engines, industrial gas turbines and diesel-electric locomotives. It has three business sectors including engineering machinery, power systems and resources. It is also a financial services provider through Caterpillar Financial Services.  
Solar Turbines, a subsidiary of Caterpillar Inc., is one of the pillars of industrial gas turbines producers and the world’s leading manufacturer in decentralized energy resources (DE) and combined heat and power (CHP). Its industrial gas turbines and a set of solutions have been widely used in such places as airports, hospitals, convention centers, and some industrial sectors including iron and steel, coking and petrochemicals.
Challenges
Coke is an important industrial material in China. Coke oven gas is one of the main by-products in coking industry. Usually, half of the coke oven gas is used to reheat and the other half is used to light sky lanterns or released into the air directly. Coke oven gas is a kind of toxic and explosive medium-btu gas. If not properly dealt with, it may do serious damage to the environment. Meanwhile, coke oven gas can also be used as energy such as electric energy and steam power. To help its clients effectively reuse the waste and create more value is what Solar Turbines wants to do.
Solutions
Solar Turbines believes the application of CHP for gas turbines is an efficient way to utilize coke oven gas. The thermal efficiency of this way is 78%, while that of traditional power plants and gas-fired boiler is only 50%. Its energy-saving function works effectively, which greatly reduces the carbon dioxide emission. Solar Turbines has different specifications of gas turbines ranging from 1MW to 20 MW. Taurus 60 can reduce 30,000 tons of CO2 emission annually. Titan 130, small and durable, can reduce 75,000 tons of CO2 emission annually.
Take the Shanxi Liheng Steel Works Co.,Ltd as an example. This company produces 2 million tons of coke every year. Solar Turbines pays much attention to the coke gas in Liheng’s by-products and communicates with this company to formulate a suitable plan. Solar Turbines suggests Liheng to use four gas turbines of Titan 130. Burning coke oven gas can generate power. In this process, the high temperature gas can be led into a waste heat boiler to produce electricity by propelling the steam turbine. The cooling water can be recycled to convert toxic coke over gas into power and thermal energy. All these steps not only protect the environment, but recycle the waste. By doing this, resources are fully utilized and the cost is effectively reduced.
Achievements
The application of gas-turbine CHP can reduce the environmental pollution and provide necessary electricity of Liheng. Since August 15^th, 2012, Liheng has ranked among the top companies in China in terms of the electric energy production, efficiency of equipment and safety index. So far, it has obtained a profit of over 600 million yuan and has also achieved a lot in recycling, energy conservation and emission reduction. According to an estimation of US Environmental Protection Agency（USEPA）, Liheng’s CHP gas turbines can reduce 301,000 tons of CO2 emission, equivalent to an annual emission of 55,000 cars. Given what Liheng has contributed to environmental protection, USEPA granted a certification to show Liheng’s achievement in this field. This is the second time for USEPA to grant such a certification to a company overseas.
Because of Solar Turbines’ effective plans, a dozen of clients have adopted CHP projects since 2005. Solar Turbines has 45 CHP units which are widely used in the coking industry and will be used in chemical industry, oil refinery and others in the near future.
Prospect
China, with the largest iron, steel and coking industry, is challenged by serious problems of resource consumption, environmental pollution and ecological damage. To address these problems, China is upgrading its distribution of natural gas and coal-gas boilers. The application of gas-turbine CHP will be the most effective way.
With more and more people knowing the environmental benefits of coke oven gas, Solar Turbines is committed to helping its clients around the world to succeed in this field. Solar Turbines will strengthen the research of this kind of technology, one of the advanced ones of Caterpillar. To promote sustainable development, Solar Turbines will improve gas turbines’ work in comprehensively utilizing industrial waste gas and converting waste gas into clean energy.