Production and utilization of biochar: A review

Biomass gasification has yet to consolidate its position compared to other techniques for exploiting biomass energy. Neither the research conducted nor the plants built in recent decades, nor even government support for this technology, have provided a sufficient boost to increase the level of implementation of gasification despite its advantages in aspects such as greater efficiency and the reduction in CO2 emissions, as there are numerous other methods of biomass energy conversion that provide stiff competition. In this paper, gasification techniques have been reviewed in depth and the main factors to be considered in the design of a gasification plant have been outlined. It is observed that there are a great number of factors involved in design and operation of a gasification plant, and many of them are critical. Moreover, having designed a plant according to certain specifications, there is a high probability that these initial conditions can vary, causing a malfunction of the plant.

Biomass gasification for electricity generation: Review of current technology barriers

Coal gasification in CO2 atmosphere and its kinetics since 1948: A brief review

Tar is unavoidable by-product during biomass gasification process. Catalytic steam reforming of tar to syngas is a promising way for the removal of tar from the gas products. However, the key issue for this way is catalyst development. To date, the developed catalysts always have advantages and disadvantages: nickel-based catalysts have high activity, but they are easily deactivated by coking; noble metal based catalysts have high catalytic activity, long-term stability and high carbon deposition resistance, but they are expensive; other transition metal catalysts such as Fe, Co and Cu exhibit a good performance, but they are also deactivated easily by carbon deposition in the case of high heavy-tar content in the tar; alkali metal catalysts also have high catalytic activity for tar reforming, but they are easy to be evaporated with the generated gases; natural catalysts have been widely applied for the steam reforming of tar due to its inexpensive, abundant and disposable, but their catalytic activities are lower than those man-made ones, and especially have low mechanical strength, making them not suitable to be used in fluidized bed reactor; zeolite is suggested to be a good catalyst support due to its high thermal/hydrothermal stability, high resistance to sulfur compounds, and easy to be regenerated; biomass char has been used as the catalyst or catalyst support in the steam reforming of tar due to its low cost and its natural production inside the biomass gasifier; even biomass ash now is considered to be a good catalyst for tar removal. In this review, to get better understanding of the mechanism of catalytic steam reforming of tar derived from biomass, tar formation, tar properties and catalytic reaction mechanism are also introduced, and prospects and challenges are summarized.

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Catalytic steam reforming of biomass tar: Prospects and challenges

Gasification is one of the promising technologies to convert biomass to gaseous fuels for distributed power generation. However, the commercial exploitation of biomass energy suffers from a number of logistics and technological challenges. In this review, the barriers in each of the steps from the collection of biomass to electricity generation are highlighted. The effects of parameters in supply chain management, pretreatment and conversion of biomass to gas, and cleaning and utilization of gas for power generation are discussed. Based on the studies, until recently, the gasification of biomass and gas cleaning are the most challenging part. For electricity generation, either using engine or gas turbine requires a stringent specification of gas composition and tar concentration in the product gas. Different types of updraft and downdraft gasifiers have been developed for gasification and a number of physical and catalytic tar separation methods have been investigated. However, the most efficient and popular one is yet to be developed for commercial purpose. In fact, the efficient gasification and gas cleaning methods can produce highly burnable gas with less tar content, so as to reduce the total consumption of biomass for a desired quantity of electricity generation. According to the recent report, an advanced gasification method with efficient tar cleaning can significantly reduce the biomass consumption, and thus the logistics and biomass pretreatment problems can be ultimately reduced.

Barriers of commercial power generation using biomass gasification gas: A review

Numerous reviews have been found related to individual studies on coal gasification (CG) and biomass gasification (BG). However, this review deals mainly with the CO-gasification (COG) of numerous types of coal and biomass and then compares their results with those obtained using coal and biomass gasification in detail. There are several process parameters which have a direct effect on the gasification process and among them temperature is the most significant one. In this paper, the production of H2, CO2, CO, CH4, and other hydrocarbons in CG, BG and COG with the variation of temperature is reviewed in detail. As it mainly influences the gaseous products and their characteristic behaviour, this review takes into account the effect of temperature on various other parameters such as carbon conversion, gas yield, calorific value, cold gas efficiency as well as tar and char contents in various kinds of coals, biomasses and their mixtures under catalytic or non-catalytic conditions.

The effect of temperature on various parameters in coal, biomass and CO-gasification: A review

The use of polymeric adsorbent for decontamination of various sources of water was critically reviewed. This arises from the alarming increase in water scarcity in many parts of the world due to increase in population, which exerts immense pressure on the available water resources. Treatment of wastewater, stormwater and seawater via series of technological pathways like adsorption, desalination, advanced oxidation and solid-phase microextraction constitute new strategies for removal of toxins, antibiotics, complex matrix samples, and heavy metals for sustainable production of potable drinking water. This study reviewed the use of polymeric adsorbents such as nano-magnetic polymers (NMPs), polysaccharides, extracellular polymeric substances (EPS), and covalent organic polymers (COPs) for effective decontamination of water. These materials were critically analyzed with emphasis on their characteristics, strengths, drawbacks, as well as the enhancement techniques. Furthermore, the mechanisms of adsorption involved were also discussed. This review shows that polymeric adsorbents have demonstrated remarkable removal efficiency for several contaminants.

Wan Mohd Wan Daud

Papers

The effect of temperature on various parameters in coal, biomass and CO-gasification: A review

Insight into wastewater decontamination using polymeric adsorbents

Insight into catalytic reduction of CO2: Catalysis and reactor design

Investigating the electrocatalytic oxidation of glycerol on simultaneous nitrogen- and fluorine-doped on activated carbon black composite