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The acidity of low and high free fatty acid containing feedstock varieties and biodiesel production intermediary products were tested using a variety of standard methods by the use of manual and automatic titration apparatus. The objective was to select the optimal test method for intermediary products in biodiesel processing and to optimize the selected technique by reducing the extent of bias. We found that there are two major reasons for variations in electrode potential readings. Colloid chemistry has an impact on the initial phase of titration by breakage and reformulation of the partially disperse system. Electric and magnetic fields in the titration beaker were the main reasons for sensitive fluctuations in electrode potentials in the potential range of interest for acid number readings. Refluxing the analyte with the diluting solvent proved to be an efficient technique to offset the influence of colloid processes. Addition of a filter electrolyte to the titration solvent allowed the filter fluctuations to be related to changes in uniformity of electric and magnetic fields in the titration beaker. Addition of filter electrolyte improved signal reliability than shading the external noises by wrapping the titration beaker in aluminium foil. Mathematical interpretation of potential readings revealed the extent of improvement in electrode potential fluctuation by the techniques employed. Both the aqueous and non-aqueous titration are suitable for accurate testing the acid number of biodiesel feedstock and intermediary products.

Summary This article applies principles of industrial ecology to small‐ and medium‐sized biodiesel production facilities. A large potential for gains in efficiency and profit are realized through technology retrofits and the novel application and reuse of process materials. Our basic criteria for sustainability of farm‐scale biodiesel production systems are measured by the following questions: Are all of the resources, mass, and energy flows in the system rational and harmonized? Is the feedstock produced without adverse effects on natural resources or the food chain? We answer these questions by presenting and applying the latest chemical engineering and technology research to support the harmonized and rationalized use of resources and energy within the system boundaries of a farm economy. The feedstock must include refuse and secondary oil sources with low impact on the food chain. Emissions must be reduced to a minimum for a smaller carbon footprint and positive emissions balance from seed to exhaust. Discharges should be avoided; wastes must be turned into primary and intermediary products or energy resources. Proper techniques and routines should serve environmental and human health and safety targets. Reuse of existing assets is considered for improving unit capacity and efficiency, thus lowering costs of conversion. Significant benefits in profitability and production capacity, combined with improved environmental performance, are the main outcomes of the recommended restructuring of production at farm‐scale.

Abstract. The aim of this paper is to investigate the effects of agricultural utilization of biodiesel byproducts. The hydrophilous by-products of transesterification, such as proteins, carbohydrates, minerals, vitamins, potassium hydroxide used as catalyser and methanol are concentrated in the phase of glycerol during biodiesel production. Agriculture can utilize these components but some effects of glycerol in soil do not serve the needs of plants. Several studies have investigated the different effects of glycerol in soil. The specific focus of our research is to analyse the relationship between seed germination and glycerol content of soil. During this research the inhibitor effect of glycerol, biodiesel by-product, and methanol on seed germination of ryegrass (Lolium perenne L.) and oilseed rape (Brassica napus) were investigated. In the case of some treatments, a different percentage of glycerol and methanol was applied, in order to establish the methanol content of soil that can balance the inhibitor effect of glycerol. Based on the obtained information, pot experiment was established with ryegrass to examine the effects on plant growth. Our research has not only studied the impact of biomass production, but variations in the rate of plant growth as an effect of different treatments were observed as well.

IntroductionThe spent Merox caustic waste (SMC) in question is a byproduct of desulfurization of light hydrocarbon fractions and products in petroleum refinery operations. Removal of sulfur is necessary because of environmentally driven product specifications for protecting life and safety of living organisms. The term of industrial ecology is used by answering simple questions, like a) are all of the resources, mass and energy flows in the system rational and harmonized? b) was the production planned and operated without adverse effect on our environment, resources and cannot interfere with food chains [1]. Light hydrocarbon fractions and products can be desulfurized by extraction or by chemical conversion. In extractive treatment a solvent that can be regenerated transfers sulfur compounds into polar phase. This phase does not mix with the apolar hydrocarbon phase and can easily be separated by settling. NaOH is a convenient agent for this. Low molecular weight acids are also separated into the water phase. The action of converting the sulfur compound reveals that the mechanism is a reactive extraction: