The potential for energy self-sufficiency in the United Kingdom rendering industry

摘要

Animal by-products (ABPs) are co-products of meat production system that include on-farm fallen stock and slaughterhouse co-products that are not fit for human consumption (different types of fat, offal and bone). Slaughterhouse co-products represent between 30 to 50% of the life weight of farm animals. In the UK, fat, offal and bone are normally handled by rendering. Rendering is a process where ABP are sized and then dried to produce rendered products: tallow and a protein meal. Depending on the category of the ABP, rendered products can be used in pet foods manufacturing, the oleochemical industry and as biofuels (with and without further processing). The UK rendering industry uses both tallow and natural gas as fuel for heat production during the drying process. A study of UK rendering plants was undertaken to determine the total tallow production and the relative proportions of tallow and natural gas used as fuels. Data on fuel and energy use was collected from five rendering plants, representing 50% of the ABP processed in the UK. The results indicate that tallow use by the UK rendering industry ranged from 15 - 100% of total heat production with the remainder being derived from natural gas. When scaled up, it can be calculated that between 2006 and 2008 the UK rendering industry required around 5.7 PJ of heat per annum. During the same period the energy potentially available from rendered tallow (usable as biofuel) was 6.7 PJ. It can be concluded that potentially the UK rendering industry could be self-sufficient in energy use. However, use of tallow as a biofuel depends on the relative cost of natural gas compared to alternative markets for tallow.