Page 1 of 8

European Journal of Applied Sciences – Vol. 12, No. 2

Publication Date: April 25, 2024

DOI:10.14738/aivp.122.16828

Emmanuel, E. E., Douglas, R. K., & Araka, P. P. (2024). An Investigation of The Temperature Profile and Drying Kinetics of a Catfish

in Biomass-Fired Kilns. European Journal of Applied Sciences, Vol - 12(2). 405-412.

Services for Science and Education – United Kingdom

An Investigation of The Temperature Profile and Drying Kinetics

of a Catfish in Biomass-Fired Kilns

Ebikabowei Enemugha Emmanuel

Department of Mechanical Engineering Niger Delta University,

Wilberforce Island, Nigeria

Reward Kokah Douglas

Department of Chemical Engineering Niger Delta University,

Wilberforce Island, Nigeria

Peremelade Perez Araka

Department of Agriculture and Environmental Engineering

Rivers State University, Port Harcourt, Nigeria

ABSTRACT

This study investigated and analyzed the temperature profile and drying kinetics of

biomass-fired kilns powered by gas, charcoal, and electricity. The study emphasized

the importance of understanding the efficiency of energy sources in drying

processes. The experimental data revealed that the drying rates varied across the

compartments (Deck 1, Deck 2, and Deck 3) of the kiln when drying catfish. Notably,

gas-powered kilns demonstrated faster drying times on Deck 3, while charcoal- powered kilns had different drying rates across all decks. Gas-powered kilns

showed faster temperatures reaching around 250-287°C across the decks in

approximately 35 minutes on average. Charcoal kilns displayed a maximum

temperature of 287-298°C, with a similar drying duration. Electricity-powered kilns

showcased variations in temperature profiles across the decks, with Deck 2 drying

faster compared to decks 1 and 3. The results from the experiments illustrated the

influence of energy sources on the drying kinetics of biomass-fired kilns. Gas,

charcoal, and electricity influenced the temperature profiles and drying rates of

catfish in the kiln's compartments, highlighting the need for optimizing energy

sources in biomass-fired kilns. These findings have implications for enhancing

drying efficiency and reducing energy consumption in industries and rural areas

reliant on biomass fuel.

Keywords: Biomass kiln, moisture ratio, temperature profile, drying kinetics, catfish.

INTRODUCTION

In Nigeria, drying is the main technique for preserving agricultural food goods. This can be

attributed to its ease of use, low energy requirements, and the seasonality of food production

compared to year-round consumption. The majority of Nigeria's geopolitical zones have

pleasant weather, particularly during the protracted dry season. While freezing and

refrigeration are much more difficult and expensive preservation methods, drying benefits

from high ambient temperatures and extremely low relative humidity. Due to excessive

Page 2 of 8

Services for Science and Education – United Kingdom 406

European Journal of Applied Sciences (EJAS) Vol. 12, Issue 2, April-2024

production without sufficient preservation plans for short periods, there is a lack of technical

and socioeconomic information about alternative food processing techniques, which results in

food being wasted in rural areas of Nigeria. This is achieved by transporting fish for an extended

period and reducing its water content between 18% and 20% on a wet basis through the

application of a charcoal charcoal-assisted dryer. Food goods should be dried to lower moisture

content, decrease weight, facilitate handling, extend shelf life, maintain food's nutritional value,

and lower the risk. The water content of food varies from 5 to 25 per cent after it is properly

dried, depending on the type of food. Therefore, to increase the amount of food available for

human consumption through processing techniques like canning, sun drying, dehydration,

smoking, curing, fermentation, freezing, refrigeration, and the use of chemical additives, it is

necessary to improve the yields of agricultural food products using appropriate food

preservation and storage methods. The majority of methods need expensive, highly specialized

equipment, continuous electricity, and/or fossil fuels like gas or oil to provide the energy

needed to run them. However, this energy is scarce or hard to get by in many regions of Nigeria,

and their cost is going up. Advanced techniques for food processing and preservation, such as

fermentation, smoking, curing, and solar drying, are becoming more and more popular.

Pyrolysis is the process of smoking fish through chemical decomposition by heat with the use

of firewood made of three components broken down in the burning process, as stated by [1].

The method of smoking is one of the oldest and best ways of preservation, which involves the

effects of salting, drying, heating, and smoking. Fish smoking can be either cold (280-320oC) or

hot (700 – 800oC). Cold smoking is not meant to cook the flesh, coagulate the proteins,

inactivate food spoilage enzymes, or eliminate food pathogens. Therefore, refrigerated storage

is important to preserve before consumption. Fishes like catfish (Tachysurus Spp.) and

Mackerel (Caranx Spp.) have a moisture content of 78.13% and 56% to 74% respectively, along

with 18.63% and 16% to 20% protein content, as reported in [2]. Fish have high moisture and

protein content, along with other constituents, with 8% to 14% fat depending on the species,

as mentioned in [3]. Freshly cut fish have a moisture content of 65% to 85% wet basis, drying

temperature of 550C to 650C, and safe dry moisture content of 25% wet basis depending on

the fish species, as stated in [4]. Fish are washed in a salt solution and dried/smoked slowly

over the fire for a 23% to 25% moisture content wet basis, as reported in [5].

Energy derived from biomass, such as wood, is used in various industries, households, and rural

areas. In some urban areas, wood and charcoal have become trade commodities. Biomass

serves as the primary source of energy for almost 40% of the world's population (about 2.4

billion people). Biomass is the fourth-largest energy source globally, according to Ayyappan &

Diwan [6]. It is used to meet the basic needs of cooking and heating in underdeveloped rural

areas. In developed countries, biomass energy is primarily utilized for power generation and

space heating. If biomass fuels were utilized more efficiently, they could offer a wider range of

energy services than they currently do. Additionally, by using biomass in the form of waste and

crop residue that is now disposed of by burning or dumping, a significant amount of energy

could be generated. Fish can be categorized as shellfish, whitefish, or oily fish. Fish is a cost- effective and nutrient-rich food that is available to more people than meat, making it a popular

choice in developing nations with high rates of malnutrition [7]. An oven is an appliance used

for baking or roasting. It uses dry heat to cook meals. In an oven, convection from circulating

air, infrared energy from the oven walls, and conduction through the tray on which the food is

placed all work concurrently to heat the food's surface [8]. The pots were often directly exposed

Page 3 of 8

407

Emmanuel, E. E., Douglas, R. K., & Araka, P. P. (2024). An Investigation of The Temperature Profile and Drying Kinetics of a Catfish in Biomass-Fired

Kilns. European Journal of Applied Sciences, Vol - 12(2). 405-412.

URL: http://dx.doi.org/10.14738/aivp.122.16828

to the flame during the pit fire, resulting in dark, black splotches. However, by managing the

fire carefully, a clean, smoke-free environment can be created, leading to well-oxidized pottery.

Some researchers [9, 10] have reported that a kiln may be considered as a chamber fed with

flames by one or more fireplaces, and from which a chimney absorbs heat and smoke. Another

approach to the concept of a kiln is a box filled with refractory materials that absorb and hold

heat directed towards it. Hot air is used during baking and roasting to obtain a suitable

outcome. However, baking and roasting are not typically used interchangeably. Roasting is used

for raw foods like meats, yams, fish, maize, etc., whereas baking is often used for flour-based

items like cakes, bread, and biscuits. These procedures alter the properties of the food items by

eliminating bacteria and reducing the food's moisture level, which can be used as a preservation

method. As noted by Ogunleye and Awogemi [11], fish provides approximately 6% of global

protein. Ovens are categorized based on how they heat, either directly or indirectly. Air,

combustion products, and indirectly heated ovens are all recirculated either naturally or with

the use of blowers. Indirectly heated ovens are often powered by natural gas, but they can also

run-on propane, butane, fuel oil, or solid fuels. Steam tubes in indirectly heated ovens are either

heated by direct fuel combustion or supplied with steam from a separate boiler. Rhodes [12]

opined that a kiln, as an oven, holds hot fires and maintains the heat necessary to drive nearly

all moisture out of biomaterial heated in its interior. The air in the baking chamber is heated by

the steam tubes, and this hot air is typically passed through the baking chamber and an

additional heat exchanger. Alternatively, fuel is burnt between two walls and the combustion

products are expelled from the upper part of the oven, or combustion gases are routed via

banks of radiator tubes in the baking chamber. Radiator plates utilizing induction heating are

used to heat electric ovens. Batch ovens heat the walls and base, whereas the heaters in

continuous ovens are located above, besides, and below a conveyor. Investigating the

temperature profile and drying kinetics of biomass-fired kilns is an important area of research,

especially for industries and rural areas that rely on biomass as a source of fuel. Understanding

the temperature profile and drying kinetics of biomass-fired kilns can help improve the

efficiency of the drying process and reduce energy waste. Thus, this study aims to explore the

temperature profile and drying kinetics of catfish in biomass-fired kilns.

MATERIALS AND METHODS

Sample Preparation and Experimentation

During the period of February-March 2019, studies were conducted to investigate temperature

profiles and drying kinetics of Catfish in biomass-fired kilns. Three (n=3) sources of energy

were used namely Gas, Mangrove fired wood and electricity was used for the study. The

experiments were carried out at the Department of Mechanical Engineering, Niger Delta

University, located at 4.970 North 6.11,0 East and 75m above sea level. The relative humidity

in the area is 85%, with a maximum temperature of about 30 degrees Celsius. Ten (n = 10)

pieces of catfish were purchased from Tombia Market in Yenagoa, which is about 25km from

the Niger Delta University. Before the investigation, the fish were prepared and washed with

clean water, then weighed using a 50 kg capacity Camry Emperor's weighing machine. The pre- weighed fishes were then spread over messes that were placed in the three partitions situated

at deck 1, deck 2, and deck 3 levels of the kiln. Each run started at 9:00 am and continued until

4:00 pm.