Oil Palm Ash/Ca(OH)₂/CaSO₄ Absorbent for Flue Gas Desulfurization

Abstract

The preparation, optimization and activity of active absorbent prepared from oil palm ash for the removal of SO 2 in flue gas from combustion systems were investigated. The absorbent was prepared from oil palm ash, calcium hydroxide and calcium sulfate using a water hydration process. A Central Composite Design (CCD) was used to study the influence of various absorbent preparation variables ± hydration period, amount of oil palm ash, and amount of CaSO 4 ± on the BET (Brunauer-Emmett-Teller) specific surface area of the resulting absorbent. The surface areas of the absorbents obtained were in the range of 18.7±147.2 m 2 /g. It was found that all three absorbent preparation variables studied have a significant positive influence on the BET surface area of the resulting absorbent. An empirical model was then developed to correlate the three absorbent preparation variables to the BET surface area of the resulting absorbent. The model showed significance at a confidence level of 95 % using Analysis of Variance (ANOVA). Based on the empirical model, a maximum specific surface area of 128.6 m 2 /g exists within the range of the experimental variables investigated. The hydration conditions that result in the maximum surface area are a hydration period of 10 h, amount of oil palm ash 15.0 g, and amount of CaSO 4 2.7 g. Experimental validations of these predicted optimum hydration conditions gave surface areas in the range of 125.9±129.5 m 2 /g. These results are in excellent agreement with the predicted value. In addition, desulfurization activity tests showed that the absorbent derived from oil palm ash/Ca(OH) 2 /CaSO 4 exhibited a higher desulfurization capacity compared to its starting materials.

Review on Various Types of Geopolymer Materials with the Environmental Impact Assessment

“…POFA is by-product from power plant that generate electricity which used palm fiber, shell and empty fruit bunches as fuel and burnt at 800 -1000 o C [11]. The production of boiler ash and POFA was estimated more than 4 million tonnes/year in Malaysia only [12]. In order to reduce environmental problems, palm oil ash has been utilized in many applications such as raw material for geopolymer composite, cement replacement in production of concrete, wastewater treatment and air purifier in cleaning atmospheric contaminants [9].…”

Mechanical properties of oil palm shell lightweight aggregate concrete containing palm oil fuel ash as partial cement replacement

“…About 4 million tonnes of Palm Oil Fuel Ash (POFA) is produced annually (Mohamed et al, 2005). POFA is an endproduct produced from the burning of pressed oil palm shell and fibre to generate power supply for the mill.…”

Value-added utilization of oil palm ash: A superior recycling of the industrial agricultural waste

“…In the perspective, gas sulfur dioxide has been identified as a major air pollutant, mainly hinges of its accumulative and detrimental effect to the survival of aquatic life, ecology and food chains, by imposing a significant influence on the mobilization and attenuation towards the formation of acid rain and urban smog, resulting in visibility impairment, buildings damages, silicosis syndrome, fatigue, bronchitis, shortness of breath, smell sense alteration, loss of appetite (respiratory failure) and even death [7,27]. A substantial amount of adsorption studies have been abounded, reporting a 100% gas removal, equivalent to a 5.06 mg/g adsorption capacity [9,27,29,35]. Under the co-treatment process, pozzolanic phenomenon begins with the elution of silica and alumina from ash particles by alkaline water (rate-limiting step), succeeding by the reaction with calcium oxide and hydroxide in the formation of calcium aluminium silicate hydrate compounds.…”

“…In Malaysia alone, the potential oil palm ash production is designated at 4 million tonnes/year [9], which striving towards huge criticisms and complaints, mainly attributed to its persistent, carcinogenic and bio-accumulative effects [10]. Increasingly, with the price of the ash disposal cost (either in landfills or ash ponds) hitting as high as $5/tonnes in developing countries and $50/tonnes in developed countries, the urgency of transforming the residue into a more valuable end product has been promulgated [11].…”